US20240011661A1 - Air conditioning system and method for constructing the same - Google Patents
Air conditioning system and method for constructing the same Download PDFInfo
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- US20240011661A1 US20240011661A1 US18/021,324 US202118021324A US2024011661A1 US 20240011661 A1 US20240011661 A1 US 20240011661A1 US 202118021324 A US202118021324 A US 202118021324A US 2024011661 A1 US2024011661 A1 US 2024011661A1
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Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/0007—Indoor units, e.g. fan coil units
- F24F1/0068—Indoor units, e.g. fan coil units characterised by the arrangement of refrigerant piping outside the heat exchanger within the unit casing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/0001—Control or safety arrangements for ventilation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/32—Responding to malfunctions or emergencies
- F24F11/36—Responding to malfunctions or emergencies to leakage of heat-exchange fluid
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/89—Arrangement or mounting of control or safety devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/08—Air-flow control members, e.g. louvres, grilles, flaps or guide plates
- F24F13/10—Air-flow control members, e.g. louvres, grilles, flaps or guide plates movable, e.g. dampers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/20—Casings or covers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
- F24F3/065—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units with a plurality of evaporators or condensers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2140/00—Control inputs relating to system states
- F24F2140/40—Damper positions, e.g. open or closed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/02—System or Device comprising a heat pump as a subsystem, e.g. combined with humidification/dehumidification, heating, natural energy or with hybrid system
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/003—Indoor unit with water as a heat sink or heat source
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/006—Compression machines, plants or systems with reversible cycle not otherwise provided for two pipes connecting the outdoor side to the indoor side with multiple indoor units
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/007—Compression machines, plants or systems with reversible cycle not otherwise provided for three pipes connecting the outdoor side to the indoor side with multiple indoor units
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/22—Preventing, detecting or repairing leaks of refrigeration fluids
- F25B2500/222—Detecting refrigerant leaks
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/005—Arrangement or mounting of control or safety devices of safety devices
Definitions
- the present invention relates to an air conditioning system and a method for constructing the air conditioning system.
- each of a liquid refrigerant pipe and a gas refrigerant pipe of a heat pump circuit is branched into a plurality of sub piping systems.
- the branched sub pipes in the sub piping systems are often provided with valves to zone the sub piping systems.
- each valve used in the heat pump system tends to become a leakage point of refrigerant, and thus needs to be regularly checked and repaired as necessary.
- a piping of a heat pump system so as to arrange a plurality of valves in one place.
- EP 3 091 314 A1 proposes to integrate a plurality of valves of the refrigerant sub pipes within a single casing to form a valve unit.
- a heatsource-side unit of the air conditioning system which includes a compressor and an outdoor heat exchanger, also includes potential leakage points of refrigerant.
- the configuration proposed by the EP 3 091 314 A1 is not sufficient to improve safety of an air conditioning system regarding refrigerant leakage.
- the object of the present invention is to provide an air conditioning system and a method for constructing an air conditioning system that can further improve safety regarding refrigerant leakage.
- a first aspect of the present invention provides an air conditioning system comprising: a compressor unit that has a compressor configured to compress first refrigerant; a heat exchanger unit that has an outdoor heat exchanger configured to exchange heat between air and the first refrigerant or between air and heat medium, the heat medium being subjected to a heat exchange with the first refrigerant; at least one indoor unit that has an indoor heat exchanger configured to exchange heat between the first refrigerant and air in a target space to be air-conditioned or between second refrigerant and air in the target space, the second refrigerant being subjected to a heat exchange with the first refrigerant; and at least one valve unit that has at least one liquid refrigerant pipe portion and at least one gas refrigerant pipe portion configured to allow the first refrigerant or the second refrigerant to flow therein between the compressor unit and the indoor unit, at least one liquid control valve disposed in the liquid refrigerant pipe portion, and at least one gas control valve disposed in the gas refrigerant pipe portion, where
- the second space being different from any of the target space and the first space means that the state of air in the second space has no direct relationship with the state of air in any of the target space and the first space.
- the first space may be an outdoor space or a space through which outdoor air is allowed to pass.
- the outdoor heat exchanger in the first space can be freely supplied with drafts of outdoor air, while the ventilation state of the second space in which the compressor unit and the valve unit are disposed can be restricted.
- the second space can be substantially closed in normal times.
- the second space can prevent or restrain the leaked refrigerant from spreading to the surrounding area. Moreover, concentration of the leaked refrigerant in the second space can be decreased by discharging the air from the second space to an external space of the second space. Furthermore, the second space can be substantially closed during a normal operation of the heat pump system, and a refrigerant leakage detection can be made based on concentration of refrigerant in this substantially closed space.
- the ventilation control structure is used in common for the compressor unit and the valve unit.
- the safety of the air conditioning system can be improved while preventing an increase in the installation cost of the system. Accordingly, with the air conditioning system according to the first aspect, it is possible to improve safety regarding refrigerant leakage at low cost, even in a case where the compressor should be arranged inside a building.
- the external space to which the air is discharged by the ventilation control structure is preferably not an outer space directly surrounding the second space or an indoor space where a human or animal could come or reside.
- the external space is preferably an outdoor space.
- the ventilation control structure includes a passage control structure that is configured to, when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, switch a state of at least one airflow passage between the second space and an outer space outside of the second space from a first passage state to a second passage state, in the second passage state air being allowed to pass through the passage more easily than in the first passage state.
- the discharge structure includes a ventilator that is configured to draw air from the second space towards an external space which is different from any of the target space and the second space, a controller that is configured to control the ventilator to operate when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, and a check air damper that is configured to keep closed an airflow passage between the second space and an outer space outside of the second space, and open the airflow passage when the ventilator is in operation.
- the second space is defined by a building structure; and the ventilator and the check air damper are disposed to the building structure.
- the second space can be obtained by utilizing a building structure of the building to which the air conditioning system is installed, and the ventilator and the check air damper can be arranged by utilizing openings formed in the building structure.
- the second space may be one of the rooms of the building, or two rooms of the building which are connected to each other to form a single continuous space.
- the building structure is configured such that the second space is substantially isolated from the outer space thereof when the ventilator is not in operation and the check air damper is closed.
- the casing and other elements of the unit may be manufactured together. Thereby, it becomes easier to design the unit so as to enhance their performances such as airtightness of its casing. It also becomes easier to optimize the dimension of the unit, and a position of a maintenance door of the casing. Hence, it is possible to improve not only safety but also maintainability and functionality of the air conditioning system.
- the casing may be a retrofitted casing which is to be assembled around elements of an existing compressor unit or valve unit.
- the air conditioning system further comprises: first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space; a first intake duct connecting the outer space of the second space and the internal space of the first casing; a second intake duct connecting the outer space of the second space and the internal space of the second casing; a connection structure connecting the internal spaces of the first and second casings; a discharge duct connecting the connection structure and the external space, wherein the first leakage detector is disposed in the first or second casing that accommodates the compressor, the check air damper is disposed to each of the first and second intake ducts, and the ventilator is disposed to the discharge duct.
- the air conditioning system further comprises: a casing accommodating the compressor unit and the valve unit as part of the second space; an intake duct connecting the outer space of the second space and the internal space of the casing; a discharge duct connecting the internal space of the casing and the external space, wherein the first leakage detector is disposed in the casing, the check air damper is disposed to the intake duct, and the ventilator is disposed to the discharge duct.
- the indoor heat exchanger is configured to exchange heat between the second refrigerant and air in the target space;
- the liquid refrigerant pipe portion and the gas refrigerant pipe portion of the valve unit are configured to allow the second refrigerant to flow therein;
- the air conditioning system further comprises a second leakage detector that is disposed in the second space and configured to detect at least a concentration of the second refrigerant in air;
- the controller is further configured to control the ventilator to start operating when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold.
- the controller in any case of when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold, and when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold, the controller is configured to control the ventilator to start operating.
- the air conditioning system is of a cascade-type which uses different types of refrigerants in the compressor unit and the valve unit, it is possible to improve the safety regarding leakage of any of the refrigerants.
- the compressor unit further has a refrigerant heat exchanger configured to exchange heat between the first refrigerant and the second refrigerant; the first leakage detector is disposed in the first casing; and the second leakage detector is disposed in the second casing or a space which is part of the second space and not part of the internal spaces of the first and second casings.
- the air conditioning system further comprise: first connection pipes connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween; and second connection pipes connecting the compressor unit, the valve unit, and the indoor unit such that the first refrigerant or the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit.
- a heat pump circuit is formed between the outdoor heat exchanger and the indoor heat exchanger.
- the air conditioning system comprises a plurality of the indoor units; and the valve unit further has at least one liquid refrigerant branch pipe branching the liquid refrigerant pipe portion towards the indoor units and at least one gas refrigerant branch pipe branching the gas refrigerant pipe portion towards the indoor units.
- the branching points of the refrigerant pipes are also potential refrigerant leakage points. Hence, since such potential leakage points are also accommodated in the second space, the safety of the air conditioning system regarding refrigerant leakage can be further improved.
- the second space is a space which is any one of a machine room, a computer room, and a warehouse in a building.
- the second space is a space where a human is unlikely to reside in normal times.
- the safety of the air conditioning system regarding refrigerant leakage can be further improved.
- a second aspect of the present invention provides a method for constructing any one of the air conditioning systems mentioned above, comprising: installing the compressor unit and the valve unit in the second space which is defined by a building structure of a building; disposing the first leakage detector in the second space; installing the heat exchanger unit in the first space; installing the indoor unit in a space which is within the building and different from the first space and the second space; connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween; connecting the compressor unit, the valve unit, and the indoor unit such that the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit; and installing the ventilation control structure to the building.
- the building structure includes a floor, a ceiling facing the floor, at least one wall which connects the floor and the ceiling and surrounds a space between the floor and a ceiling, and a door arranged in the floor, the ceiling, or the wall.
- a reference example of a safety system comprises: a plurality of valve units used for a heat pump system, each of the valve units having at least one liquid refrigerant pipe portion, at least one gas refrigerant pipe portion, at least one liquid control valve disposed in the liquid refrigerant pipe portion, at least one gas control valve disposed in the gas refrigerant pipe portion, a casing accommodating at least the liquid control valve and the gas control valve and formed with at least two openings, and a refrigerant leakage detector configured to detect an occurrence of a refrigerant leakage in an internal space of the casing; a connection structure connecting the internal spaces of the casings via the openings; and a discharge structure connected to the connection structure or one of the casings, and configured to discharge air from the internal space of the casing in which a refrigerant leakage has occurred.
- the casing accommodating the valve can prevent or restrain the leaked refrigerant from spreading to the surrounding area.
- concentration of the leaked refrigerant in the internal space of the casing can be decreased by discharging the air from the internal space to an external space of the casings.
- each casing can be substantially closed during a normal operation of the heat pump system, and a refrigerant leakage detection can be made based on concentration of refrigerant in this substantially closed space.
- the external space to which the air is discharged by the discharge structure is preferably not an outer space directly surrounding any casing or an indoor space where a human or animal could come or reside.
- the external space is preferably an outdoor space.
- the heat pump system to which a plurality of the valve units belong may include a plurality of separate heat pump circuits.
- the pipings of the valve units need not necessary be connected to each other.
- the pipe portions, the valves, and the casing may be manufactured together. Thereby, it becomes easier to design the valve unit so as to enhance its performance such as airtightness of the casing. It also becomes easier to optimize the dimension of the valve unit, and a position of a maintenance door of the casing. Hence, it is possible to improve not only safety but also maintainability and functionality of the valve unit.
- the casing may be a retrofitted casing which is to be assembled around existing valves.
- the discharge structure includes a shared duct connected to the connection structure or one of the casings, and a ventilator disposed to the shared duct.
- the ventilator may be configured to blow air to push the air within the casing out, or suck air to draw the air in the casing out.
- the shared duct may be extended to the outdoor space, and the ventilator may be disposed in or attached to the shared duct.
- the ventilator may be configured to further discharge air surrounding at least one of the casings, e.g. air in a ceiling or a pipe shaft.
- the shared duct has a first end and a second end; the ventilator is disposed to the shared duct at or close to the second end, and configured to draw air in the shared duct towards the second end; and the shared duct is connected to the connection structure or one of the casings on a side of the first end with respect to the ventilator.
- the second end of the shared duct is open to an outdoor space.
- the air containing refrigerant can be discharged to the outdoor space.
- the safety of the heat pump system can be further improved.
- the safety system further includes: a controller configured to control the ventilator to start operating when a refrigerant leakage in any one of the valve units has occurred.
- each of the refrigerant leakage detectors are configured to output detection result information; and the controller is configured to receive the detection result information outputted from any one of the refrigerant leakage detectors, and identify in which of the valve units a refrigerant leakage has occurred based on the received detection result information.
- the at least two openings of each of the casings include a first opening and a second opening: and the connection structure includes a plurality of individual ducts connected to the second openings of the casings, respectively, and further connected to the shared duct in common.
- the controller includes a plurality of unit controllers disposed in the valve units, respectively, and a central controller configured to communicate with the unit controllers; each of the refrigerant leakage detectors is configured to transmit detection result information to the central controller via the corresponding unit controller; and the central controller is configured to determine whether a refrigerant leakage in any one of the valve units has occurred based on the detection result information received from the valve unit, and, when the refrigerant leakage has occurred in any one of the valve units, transmit a damper open command to the damper of the valve unit in which the refrigerant leakage has occurred via the corresponding unit controller and control the ventilator to start operating.
- the detection result information indicates whether or not a refrigerant leakage in the valve unit has occurred, and may indicate an identification of the valve unit of refrigerant leakage.
- the damper open command instructs the damper to open, and may designate an identification of the valve unit of which the damper should open.
- the at least two openings of each of the casings include a first opening and a second opening;
- the connection structure includes at least one connecting duct connected on one side to the second opening of one of the casings and connected on another side to the first opening of another one of the casings;
- the shared duct of the discharge structure is connected to the second opening of one of the casings to which there is no connecting duct connected.
- the controller includes a plurality of unit controllers disposed in the valve units, respectively, and a central controller configured to communicate with the unit controllers; each of the refrigerant leakage detectors is configured to transmit detection result information to the central controller via the corresponding unit controller; and the central controller is configured to determine whether a refrigerant leakage in any one of the valve units has occurred based on the detection result information received from the valve unit, and, when the refrigerant leakage has occurred, transmit a damper open command to the dampers of all the valve units via the unit controllers and control the ventilator to start operating.
- the detection result information indicates whether or not a refrigerant leakage in the valve unit has occurred, and may indicate an identification of the valve unit of refrigerant leakage.
- the damper open command instructs the damper to open, and may designate an identification of the valve unit of which the damper should open.
- a reference example of a method for assembling any one of the safety systems mentioned above, wherein the casing is formed from a plurality of casing parts comprises: arranging, for each of the valve units, the corresponding casing parts around at least the liquid control valve and the gas control valve of the valve unit; fixing, for each of the valve units, the corresponding casing parts to each other; disposing, for each of the valve units, the refrigerant leakage detector, arranging the connection structure so as to connect the internal spaces of the casings; and connecting the discharge structure to the connection structure or one of the casings.
- a reference example of an air conditioning system comprises: any one of the safety systems mentioned above, a heatsource-side unit including a compressor and a heatsource-side heat exchanger; a plurality of utilization-side units each including a utilization-side heat exchanger; a liquid refrigerant piping extending between the heatsource-side unit and the utilization-side units, and including the liquid refrigerant pipe portions; a gas refrigerant piping extending between the heatsource-side unit and the utilization-side units, and including the gas refrigerant pipe portions; and an expansion mechanism disposed in the liquid refrigerant piping.
- the air conditioning system further comprises: a system controller configured to control an air conditioning operation of the air conditioning system, wherein at least part of the controller of the safety system is a part of the system controller.
- the air conditioning system further comprises: a plurality of sections each including the plurality of valve units, the connection structure, and the discharge structure, wherein the controller is configured to control the ventilator of only the section in which a refrigerant leakage has occurred to start operating.
- FIG. 1 is a schematic configuration diagram of an air conditioning system with valve units according to a first embodiment of the present invention.
- FIG. 3 is a schematic configuration diagram of a safety system according to the first embodiment.
- FIG. 4 is a flow chart indicating an operation performed by a unit controller shown in FIG. 3 .
- FIG. 5 is a flow chart indicating an operation performed by a central controller shown in FIG. 3 .
- FIG. 6 is a schematic configuration diagram of the safety system according to a second embodiment of the present invention.
- FIG. 7 is a flow chart indicating an operation performed by a central controller shown in FIG. 6 .
- FIG. 8 is a schematic configuration diagram of the safety system according to a third embodiment of the present invention.
- FIG. 9 is a grouping table used by a central controller shown in FIG. 9 .
- FIG. 11 is a grouping table used by the central controller according to a fourth embodiment of the present invention.
- FIG. 13 is a schematic configuration diagram of an air conditioning system according to a fifth embodiment of the present invention.
- FIG. 14 is a schematic configuration diagram of a safety system of the air conditioning system shown in FIG. 13 .
- FIG. 15 is a flow chart indicating an operation performed by a central controller shown in FIG. 14 .
- FIG. 16 is a schematic configuration diagram of a safety system according to a first variation of the fifth embodiment.
- FIG. 17 is a schematic configuration diagram of a safety system according to a second variation of the fifth embodiment.
- FIG. 18 is a schematic configuration diagram of a safety system according to a third variation of the fifth embodiment.
- FIG. 20 is a schematic configuration diagram of an example of a safety system of the air conditioning system shown in FIG. 19 .
- FIG. 21 is a flow chart indicating an operation performed by a central controller shown in FIG. 20 .
- FIG. 22 is a schematic configuration diagram of an air conditioning system according to a seventh embodiment of the present invention.
- FIG. 23 is a schematic configuration diagram of a variation of the safety system according to any one of the fifth to seventh embodiments.
- the air conditioning systems according to a first embodiment of the present embodiment is a multi air conditioning system with a so-called three-pipe configuration, which includes a heatsource-side unit and a plurality of utilization-side units.
- FIG. 1 is a schematic configuration diagram of the air conditioning system according to the first embodiment.
- the air conditioning system 100 comprises a heatsource-side unit 110 , and a plurality of utilization-side units 120 connected to the heatsource-side unit 110 via refrigerant pipes.
- the utilization-side units 120 are divided into a plurality of unit families 121 , e.g. first to third unit families 121 _ 1 , 121 _ 2 , 121 _ 3 .
- the number of the unit families 121 is not limited to three, and may be two, four, or more.
- the number of the utilization-side unit 120 belonging to each of the unit families 121 is also not limited.
- the heatsource-side unit 110 includes a compressor, and a condenser and an evaporator (heatsource-side heat exchangers) (not shown).
- the heatsource-side unit 110 also extends out a liquid refrigerant pipe 131 , a low-pressure gas refrigerant pipe 132 , and a high-pressure gas refrigerant pipe 133 .
- the liquid refrigerant pipe 131 communicates with each of the condenser and the evaporator.
- the low-pressure gas refrigerant pipe 132 communicates with a suction port of the compressor.
- the high-pressure gas refrigerant pipe 133 communicates with a discharge port of the compressor.
- the liquid refrigerant pipe 131 branches into a plurality of heatsource-side liquid pipes 141 towards the first to third unit families 121 _ 1 , 121 _ 2 , 121 _ 3 .
- the low-pressure gas refrigerant pipe 132 branches into a plurality of heatsource-side low-pressure gas pipes 142 towards the first to third unit families 121 _ 1 , 121 _ 2 , 121 _ 3 .
- the high-pressure gas refrigerant pipe 133 branches into a plurality of heatsource-side high-pressure gas pipes 143 towards the first to third unit families 1211 , 1212 , 121 _ 3 .
- the heatsource-side liquid pipe 141 branches into a plurality of utilization-side liquid refrigerant pipes 151 towards the utilization-side units 120 which belong to the unit family 121 .
- the heatsource-side low-pressure gas pipe 142 branches into a plurality of utilization-side gas refrigerant pipes 152 towards the utilization-side units 120 which belong to the unit family 121 .
- the heatsource-side high-pressure gas pipe 143 branches towards the utilization-side units 120 which belong to the unit family 121 , and each of the branched pipes merges with the corresponding utilization-side gas refrigerant pipe 152 .
- Each of the utilization-side units 120 includes a utilization-side heat exchanger (not shown). For each of the utilization-side units 120 , the utilization-side heat exchanger communicates with the corresponding utilization-side liquid refrigerant pipe 151 and utilization-side gas refrigerant pipe 152 .
- a liquid refrigerant piping and a gas refrigerant piping extends between the heatsource-side unit 110 and the utilization-side units 120 , while branching towards the unit families 121 and then towards the utilization-side units 120 in each of the unit families 121 , to form a heat pump circuit.
- a liquid refrigerant piping and a gas refrigerant piping extends between the heatsource-side unit 110 and the utilization-side units 120 , while branching towards the unit families 121 and then towards the utilization-side units 120 in each of the unit families 121 , to form a heat pump circuit.
- the air conditioning system 100 further includes first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 for the first to third unit families 121 _ 1 , 121 _ 2 , 120 _ 3 , respectively.
- the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 have a substantially same configuration.
- the term “the valve unit 200 ” means any one of the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 .
- the details of the valve unit 200 are explained hereinafter.
- the air conditioning system 100 includes a safety system for improving safety of the air conditioning system 100 (a heat pump system) regarding refrigerant leakage.
- the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 are part of the safety system. The details of the safety system will be explained later.
- FIG. 2 is a schematic configuration diagram of the valve unit 200 .
- the valve unit 200 comprises a multi branch selector 300 , a casing 400 , a damper 440 , a refrigerant leakage detector 500 , and a unit controller 600 .
- the casing 400 accommodates the multi branch selector 300 therein.
- the refrigerant leakage detector 500 and the unit controller 600 are disposed in an internal space 401 of the casing 400 .
- the unit controller 600 may be disposed on or outside the casing 400 .
- the multi branch selector 300 includes a heatsource-side liquid pipe portion 310 , a plurality of utilization-side liquid pipe portions 311 , a low-pressure gas pipe portion 320 , a plurality of low-pressure gas sub pipes 321 , a plurality of utilization-side gas pipe portions 330 , a high-pressure gas pipe portion 340 , a plurality of high-pressure gas sub pipes 341 , a plurality of bypass pipes 351 , and a plurality of refrigerant heat exchangers 352 .
- the multi branch selector 300 further includes a plurality of low-pressure gas control valves 361 , a plurality of high-pressure gas control valves 362 , a plurality of expansion mechanisms 363 , a plurality of liquid shut-off valves 364 , and a plurality of gas shut-off valves 365 .
- the numbers of the utilization-side liquid pipe portions 311 , the low-pressure gas sub pipes 321 , the utilization-side gas pipe portions 330 , the high-pressure gas sub pipes 341 , the bypass pipes 351 , the refrigerant heat exchangers 352 , the low-pressure gas control valves 361 , the high-pressure gas control valves 362 , the expansion mechanisms 363 , the liquid shut-off valves 364 , and the gas shut-off valves 365 may be the same as the number of the utilization-side units 120 which belong to the corresponding unit family 121 (see FIG. 1 ).
- the heatsource-side liquid pipe portion 310 , the low-pressure gas pipe portion 320 , the high-pressure gas pipe portion 340 are parts of the corresponding heatsource-side liquid pipe 141 , heatsource-side low-pressure gas pipe 142 , and heatsource-side high-pressure gas pipe 143 (see FIG. 1 ).
- the utilization-side liquid pipe portions 311 are parts of the corresponding utilization-side liquid refrigerant pipes 151 (see FIG. 1 ).
- the low-pressure gas sub pipes 321 , the high-pressure gas sub pipes 341 , and the utilization-side gas pipe portions 330 are parts of the corresponding utilization-side gas refrigerant pipes 152 (see FIG. 1 ).
- One of the utilization-side liquid pipe portions 311 and one of the utilization-side gas pipe portions 330 communicate with the same utilization-side heat exchanger of one of the utilization-side units 120 .
- each of the utilization-side gas pipe portions 330 branches into the low-pressure gas pipe portion 320 and the high-pressure gas pipe portion 340 via one of the low-pressure gas sub pipes 321 and one of the high-pressure gas sub pipes 341 .
- the bypass pipes 351 are connected to the utilization-side liquid pipe portions 311 , respectively, and each connected to the low-pressure gas pipe portion 320 .
- one of the bypass pipes 351 branches from one of the utilization-side liquid pipe portions 311 and merges with the low-pressure gas pipe portion 320 .
- the expansion mechanisms 363 are disposed in the bypass pipes 351 , respectively. Each of the expansion mechanisms 363 is configured to decompress and expand refrigerant flowing from the corresponding utilization-side liquid pipe portion 311 in the bypass pipe 351 . Each of the expansion mechanisms 363 may be an electric expansion valve.
- the refrigerant heat exchangers 352 are provided to the bypass pipes 351 , respectively.
- Each of the refrigerant heat exchangers 352 is configured to cause a heat-exchange between refrigerant flowing in one of the utilization-side liquid pipe portions 311 and refrigerant flowing in the corresponding bypass pipe 351 that has been decompressed and expanded by the corresponding expansion mechanism 363 .
- each of the refrigerant heat exchangers 352 forms a subcooling system in combination with the corresponding utilization-side liquid pipe portion 311 , bypass pipe 351 , and expansion mechanism 363 .
- Each of the refrigerant heat exchangers 352 may have two flow channels which form a part of the utilization-side liquid pipe portion 311 and a part of the bypass pipe 351 , respectively, and have thermal conductance therebetween.
- the low-pressure gas control valves 361 are disposed in the low-pressure gas sub pipes 321 , respectively. Each of the low-pressure gas control valves 361 is configured to switch between an open state and a closed state, i.e. whether or not to allow refrigerant to flow between the low-pressure gas pipe portion 320 and the corresponding utilization-side gas pipe portion 330 . The state of each of the low-pressure gas control valves 361 is controlled by the unit controller 600 in accordance with an operation mode desired for the corresponding utilization-side unit 120 . Each of the low-pressure gas control valves 361 may be an electric valve.
- the high-pressure gas control valves 362 are disposed in the high-pressure gas sub pipes 341 , respectively. Each of the high-pressure gas control valves 362 is configured to switch between an open state and a closed state, i.e. whether or not to allow refrigerant to flow between the high-pressure gas pipe portion 340 and the corresponding utilization-side gas pipe portion 330 . The state of each of the high-pressure gas control valves 362 is controlled by the unit controller 600 in accordance with an operation mode desired for the corresponding utilization-side unit 120 . Each of the high-pressure gas control valves 362 may be an electric valve, and preferably formed with a minute channel.
- the liquid shut-off valves 364 are disposed in the utilization-side liquid pipe portions 311 , respectively.
- the gas shut-off valves 365 are disposed in the utilization-side gas pipe portions 330 , respectively.
- the liquid shut-off valve 364 and the gas shut-off valve 365 disposed in the utilization-side liquid pipe portion 311 and the utilization-side gas pipe portion 330 which communicate with the same utilization-side heat exchanger define a utilization-side piping section which extends therebetween and includes at least the utilization-side heat exchanger.
- Each of the liquid shut-off valves 364 and the gas shut-off valves 365 may be an electric valve.
- the casing 400 may have a substantially box shape, and is large enough to accommodate at least the multi branch selector 300 and the refrigerant leakage detector 500 therein.
- the casing 400 may be made of metal plates, carbon fibre plates, fire-retardant resin plates, or the like.
- the casing 400 is formed with a plurality of pipe apertures 410 .
- the plurality of pipe apertures 410 are configured to allow the pipes extending from the multi branch selector 300 (hereinafter referred to as “the extending pipes”) to pass therethrough, respectively.
- the plurality of pipe apertures 410 are formed at positions corresponding to the positions of the extending pipes, and each have diameter greater than the diameter of the corresponding extending pipe.
- such extending pipes include the heatsource-side liquid pipe portion 310 , the low-pressure gas pipe portion 320 , the high-pressure gas pipe portion 340 , the utilization-side liquid pipe portions 311 , and the utilization-side gas pipe portions 330 .
- Each of the extending pipes may have a pipe connection part 370 for being connected to the corresponding outer pipes, i.e. the other part of the corresponding heatsource-side liquid pipe 141 , heatsource-side low-pressure gas pipe 142 , heatsource-side high-pressure gas pipe 143 , utilization-side liquid refrigerant pipe 151 , or utilization-side gas refrigerant pipe 152 (see FIG. 1 ). It is preferable that the pipe connection parts 370 are arranged outside of the casing 400 .
- the casing 400 is further formed with a first opening 420 , and a second opening 430 . It is preferable that the first opening 420 and the second opening 430 are arranged on opposite sides of the casing 400 with respect to the center part of the internal space 401 .
- both the first opening 420 and the second opening 430 are arranged closer to the top part of the casing 400 .
- the arrangement of the first opening 420 and the second opening 430 is not limited to the above.
- the damper 440 is directly attached to the first opening 420 .
- the damper 440 may be arranged away from the first opening 420 inside or outside the casing 400 , and connected to the first opening 420 via a duct.
- the damper 440 is configured to block air to pass through the first opening 420 when the damper 440 is closed and allow air to pass through the first opening 420 when the damper 440 is open.
- the damper 440 includes a flap 441 , and an electric motor (not shown) for moving the flap to switch between a closed position in which the flap closes off the first opening 420 and an open position in which the flap does not close off the first opening 420 .
- the motor is controlled by the unit controller 600 as explained later.
- the damper 440 may be a normally closed damper which is closed during a normal operation of the air conditioning system 100 , i.e. when no refrigerant leakage has occurred.
- the second opening 430 is configured to allow air to pass therethrough between the internal space 401 and an external space outside the casing 400 .
- a duct is connected to second opening 430 on the outside of the casing 400 .
- the second opening 430 may be provided with a damper which is controlled to move synchronously with the damper 440 of the first opening 420 .
- the casing 400 has a maintenance door configured to allow a monitoring/maintenance person to check the states of the multi branch selector 300 , the refrigerant leakage detector 500 , and the unit controller 600 , and/or repair them through the opened door, as necessary.
- Insulators 450 are applied to the casing 400 such that the internal space 401 of the casing 400 is substantially isolated from the external space outside the casing 400 at the parts other than the first opening 420 and the second opening 430 .
- the insulators 450 may include tubular insulators fitted into the gaps between outer surfaces of the extending pipes of the multi branch selector 300 and inner edges of the pipe apertures 410 , respectively.
- Each insulator 450 may be a foam tube, a foam wrap, a foam filler, a caulk, a tape, or the like. The foam tube with a cut line extending in its axis direction is easy to fit into the gap.
- the thickness of the foam tube is preferably equal to or slightly greater than the clearance between the outer surface of the corresponding extending pipe and the inner surface of the corresponding pipe aperture 410 .
- the insulators 450 may be attached to the extending pipes before assembling the casing 400 .
- the insulators 450 may also be applied to other gaps in the casing 400 , such as the gap between the flap 441 in the closed position and a housing of the damper 440 , the gap between the housing of the damper 440 and edges of first opening 420 , and the gap between the maintenance door and a door frame of the casing 400 .
- the refrigerant leakage detector 500 is configured to detect an occurrence of a refrigerant leakage in the internal space 401 of the corresponding casing 400 .
- the refrigerant leakage detector 500 is configured to detect a concentration of the refrigerant in an air surrounding the refrigerant leakage detector 500 , and continuously or regularly output a detector signal indicating a detection value Vs which corresponds to the detected concentration to the unit controller 600 .
- the refrigerant leakage detector 500 may be a semi-conductor gas sensor reactive to the refrigerant used in the air conditioning system 100 . In a case where refrigerant which is heavier than atmospheric air, such as R32 refrigerant, the refrigerant leakage detector 500 is preferably disposed in the internal space 401 at or close to an inner bottom surface of the casing 400 .
- the unit controller 600 determines whether a refrigerant leakage in the corresponding casing 400 (hereinafter referred to as “the refrigerant leakage”) has occurred based on the detection value Vs of the refrigerant leakage detector 500 .
- the detection value Vs is detection result information indicating whether the refrigerant leakage in the corresponding valve unit 200 has occurred.
- the unit controller 600 is configured to control operation of the valve unit 200 via wired communication paths and/or wireless communication paths (partially not shown) between the unit controller 600 and the machineries in the valve unit 200 .
- the unit controller 600 is configured to receive the detector signal from the refrigerant leakage detector 500 and determine whether the refrigerant leakage has occurred based on the detector signal.
- the unit controller 600 is configured to output a leakage signal to a later-mentioned central controller.
- a leakage signal indicates a unit ID (identification) of the valve unit 200 in which the leakage detector 500 is disposed, and indicates that the refrigerant leakage has occurred in the valve unit 200 of the unit ID indicated by the leakage signal.
- a leakage signal is detection result information indicating whether the refrigerant leakage in the corresponding valve unit 200 has occurred.
- the corresponding low-pressure gas control valve 361 is opened and the corresponding high-pressure gas control valve 362 and expansion mechanism 363 are closed.
- the corresponding high-pressure gas control valve 362 and expansion mechanism 363 are opened and the corresponding low-pressure gas control valve 361 is closed.
- the unit controller 600 may perform such an operation based on signals which indicate the desired operation modes of the corresponding utilization-side units 120 . Such signals may be sent from the heatsource-side unit 110 , the corresponding utilization-side units 120 , and/or an information output device (not shown) used by the monitoring/maintenance person.
- the unit controller 600 includes an arithmetic circuit such as a CPU (Central Processing Unit), a work memory used by the CPU such as a RAM (Random Access Memory), and a recording medium storing control programs and information used by the CPU such as a ROM (Read Only Memory), although they are not shown.
- the unit controller 600 is configured to perform information processing and signal processing by the CPU executing the control programs to control the operation of the valve unit 200 .
- the casing 400 , the first opening 420 , the second opening 430 , the damper 440 , the insulators 450 , the refrigerant leakage detector 500 , and the unit controller 600 are part of the safety system of the air conditioning system 100 .
- the safety system 700 of the air conditioning system 100 comprises the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 , first to third individual ducts 710 _ 1 to 710 _ 3 , a shared duct 720 , a ventilator 730 , and a central controller 800 .
- the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 have the first to third internal spaces 401 _ 1 , 401 _ 2 , 401 _ 3 of the first to third casings 400 _ 1 , 400 _ 2 , 400 _ 3 , respectively.
- the multi branch selectors 300 of the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 are omitted.
- the first to third individual ducts 710 _ 1 to 710 _ 3 correspond to the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 , respectively.
- the first to third individual ducts 710 _ 1 to 710 _ 3 have a substantially same configuration with respect to the corresponding individual duct 710 .
- the term “the individual duct 710 ” means any one of the first to third individual ducts 710 _ 1 to 710 _ 3 .
- the individual duct 710 is connected to the second opening 430 of the casing 400 of the corresponding valve unit 200 at one end of the individual duct 710 .
- the individual duct 710 is further connected to the shared duct 720 at another end of the individual duct 710 .
- the first to third individual ducts 710 _ 1 to 710 _ 3 are connected to the shared duct 720 in common.
- the ventilator 730 is disposed to the shared duct 720 at or close to one end (hereinafter referred to as “the second end”) of the shared duct 720 , and configured to draw air in the shared duct 720 towards the second end. It is preferable that the second end of the shared duct 720 is open to an outdoor space. It is also preferable that the ventilator 730 is disposed at the second end as shown in FIG. 3 .
- the operation of the ventilator 730 is controlled by the central controller 800 . For instance, the ventilator 730 starts operating when the ventilator 730 has received a ventilator start command from the central controller 800 .
- the ventilator 730 may be a fan.
- the ventilator 730 may be provided with a check air damper which is configured to prevent an air from passing through the ventilator 730 when the ventilator 730 is not in operation.
- the shared duct 720 is connected to the first to third individual ducts 710 _ 1 to 710 _ 3 on a side of another end (hereinafter referred to “the first end”) of the shared duct 720 with respect to the ventilator 730 .
- the whole structure of the first to third individual ducts 710 _ 1 to 710 _ 3 and the shared duct 720 forms a branching duct. Any one of the branching parts of this structure may be deemed as the first end of the shared duct 720 .
- the part between the point branching towards the first valve unit 200 _ 1 and the point branching towards the second valve unit 200 _ 2 may be deemed as any one of a part of the shared duct 720 , a part of second individual duct 710 _ 2 , and a part of third individual duct 710 _ 3 .
- the first to third individual ducts 710 _ 1 to 710 _ 3 form a connection structure which connects the first to third internal spaces 4011 , 401 _ 2 , 401 _ 3 via the first to third second openings 430 _ 1 , 4302 , 4303 , respectively.
- an extension duct may be connected to each of all or part of the first openings 420 on the outer side of the corresponding casing 400 .
- an air path AP can be formed that extends from an external space outside the corresponding casing 400 to the ventilator 730 .
- This air path AP passes through the first opening 420 with the damper 440 open, the corresponding internal space 401 , second opening 430 and individual duct 710 , and the shared duct 720 . If the ventilator 730 operates in this state, the air in the internal space 401 of the casing 400 with the damper 440 open is discharged by the suction force of the ventilator 730 . Meanwhile, as for the casing 400 with the damper 440 closed, the above air path AP is not formed.
- FIG. 3 depicts a situation where only the first damper 440 _ 1 is open.
- the shared duct 720 and the ventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from the internal space 401 of the casing 400 with the damper 440 open.
- the central controller 800 is configured to control the ventilator 730 to start operating (turn ON). Moreover, the central controller 800 is configured to, in cooperation with the first to third unit controllers 600 _ 1 , 600 _ 2 , 600 _ 3 , identify in which of the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 the refrigerant leakage has occurred, and control the first to third dampers 440 _ 1 , 440 _ 2 , 440 _ 3 .
- the central controller 800 is configured to control the first to third dampers 440 _ 1 , 440 _ 2 , 440 _ 3 such that, when the ventilator 730 operates due to the occurrence of the refrigerant leakage, the damper 440 of the valve unit 200 of refrigerant leakage is open while the other dampers 440 are closed.
- the discharge structure mentioned above can discharge air from the internal space 401 of the casing 400 with refrigerant leakage.
- the central controller 800 includes an arithmetic circuit such as a CPU, a work memory used by the CPU such as a RAM, and a recording medium storing control programs and information used by the CPU such as a ROM, although they are not shown.
- the central controller 800 is configured to perform information processing and signal processing by the CPU executing the control programs to control at least the operation of the safety system of the air conditioning system 100 .
- the unit controller 600 is configured to detect an occurrence of a refrigerant leakage in the corresponding casing 400 .
- the unit controller 600 is further configured to, when the refrigerant leakage has occurred, inform of the detection result to the central controller 800 and control the corresponding damper 440 to open which is normally closed under control of the central controller 800 . More specifically, the unit controller 600 is configured to perform the following operation.
- FIG. 4 is a flow chart indicating an operation performed by the unit controller 600 .
- step S 1010 the unit controller 600 acquires the detection value Vs from the detector signal outputted from the refrigerant leakage detector 500 .
- the unit controller 600 may passively receive the detector signal which is continuously or regularly outputted from the refrigerant leakage detector 500 , or actively request the refrigerant leakage detector 500 to output the detector signal regularly.
- the obtained detection value Vs basically reflects the variation in the concentration of the refrigerant in the casing 400 .
- step S 1020 the unit controller 600 compares the detection value Vs acquired and a detection value threshold Vth, and determines whether the detection value Vs is less than the detection value threshold Vth.
- the unit controller 600 may obtain a moving average value of the detection values Vs in a certain time length to use the moving average value as the detection value Vs which is compared with the detection value threshold Vth.
- the detection value threshold Vth is stored in the unit controller 600 in advance.
- the detection value threshold Vth may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the detection value threshold Vth is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the refrigerant used.
- LFL Lower Flammability Limit
- the unit controller 600 proceeds to later-mentioned step S 1030 . If the detection value Vs is less than the detection value threshold Vth (S 1020 : Yes), the unit controller 600 proceeds to later-mentioned step S 1040 . It can be said that the refrigerant leakage detectors 500 transmits detection result information to the central controller 800 via the corresponding unit controller 600 by steps from S 1010 to S 1030 .
- step S 1030 the unit controller 600 transmits to the central controller 800 a leakage signal indicating the unit ID of the valve unit 200 to which the unit controller 600 belongs (hereinafter referred to as “the own unit ID”).
- the unit controller 600 may directly send a leakage signal to the central controller 800 or indirectly send a leakage signal to the central controller 800 via one or more of other unit controllers 600 .
- the unit controllers 600 sends the leakage signal to the other unit controller 600 , and the leakage signal is relayed in series by the unit controllers 600 . For instance, when the communication path 801 is arranged as shown in FIG.
- the unit controller 600 _ 3 of the third valve unit 200 _ 3 directly sends a leakage signal to the central controller 800
- the unit controller 600 _ 2 of the second valve unit 200 _ 2 sends a leakage signal to the central controller 800 via the unit controller 600 _ 3 of the third valve unit 200 _ 3 .
- the unit controller 600 may determine the controller to which the leakage signal should be sent based on network information regarding the communication path between the unit control 600 and the central controller 800 .
- the network information may be stored in the unit controller 600 in advance, or acquired by making an inquiry to the other unit controller or controllers 600 and/or the central controller 800 .
- step S 1040 the unit controller 600 determines whether a leakage signal has been received at the unit controller 600 that was transmitted from the other unit controller 600 . If a leakage signal has been received (S 1040 : Yes), the unit controller 600 proceeds to step S 1050 . If a leakage signal has not been received (S 1040 : No), the unit controller 600 proceeds to later-mentioned step S 1060 .
- step S 1050 the unit controller 600 forwards the received leakage signal towards the central controller 800 .
- the unit controller 600 may directly send the received leakage signal to the central controller 800 or indirectly send the received leakage signal to the central controller 800 via one or more of other unit controllers 600 .
- the unit controller 600 may determine the controller to which the received leakage signal should be sent based on the network information mentioned above.
- step S 1060 the unit controller 600 determines whether a ventilator start command has been received at the unit controller 600 .
- a ventilator start command is a command transmitted from the central controller 800 . If a ventilator start command has been received (S 1060 : Yes), the unit controller 600 proceeds to step S 1070 . If a ventilator start command has not been received (S 1060 : No), the unit controller 600 proceeds to later-mentioned step S 1080 .
- step S 1070 the unit controller 600 forwards the received ventilator start command towards the ventilator 730 .
- the unit controller 600 may directly send the received ventilator start command to the ventilator 730 or indirectly send the received ventilator start command to the ventilator 730 via one or more of other unit controllers 600 .
- the unit controller 600 may determine the unit controller 600 to which the ventilator start command should be sent based on the network information mentioned above.
- step S 1080 the unit controller 600 determines whether a damper open command has been received at the unit controller 600 that was transmitted from the central controller 800 . If a damper open command has been received (S 1080 : Yes), the unit controller 600 proceeds to step S 1090 . If a damper open command has not been received (S 1080 : No), the unit controller 600 proceeds to later-mentioned step S 1110 .
- step S 1090 the unit controller 600 further determines whether the received damper open command designates the valve unit 200 to which the unit controller 600 belongs (hereinafter referred to as “the own valve unit”) as the valve unit 200 which should open its damper 440 .
- the unit controller 600 may make this determination based on whether the received damper open command designates the own unit ID. If the damper open command does not designate the own valve unit (S 1090 : No), the unit controller 600 proceeds to step S 1100 . If the damper open command designates the own valve unit (S 1090 : Yes), the unit controller 600 proceeds to later-mentioned step S 1120 .
- step S 1100 the unit controller 600 forwards the received damper open command towards the other unit controller 600 which has not received the damper open command.
- the unit controller 600 may determine the unit controller 600 to which the received damper open command should be sent based on the network information mentioned above.
- step S 1110 the unit controller 600 determines whether termination of operation has been designated. The designation may be made by a user operation, another device, or the unit controller 600 itself. If termination of the operation has not been designated (S 1110 : No), the unit controller 600 goes back to step S 1010 to repeat the above acquisition and determination steps. If termination of the operation has been designated (S 1110 : Yes), the unit controller 600 terminates its operation.
- step S 1120 the unit controller 600 controls the damper 440 of the own valve unit 200 to open, and then terminates its operation.
- the unit controller 600 controls the state of the damper 440 by controlling a supply of electricity thereto.
- the unit controller 600 may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to the unit controller 600 .
- Steps S 1040 and S 1050 may be performed before steps S 1010 to S 1030 .
- Steps S 1080 to S 1100 may also be performed before steps S 1040 and S 1050 .
- each of the unit controllers 600 can report to the central controller 800 the occurrence of the refrigerant leakage, and control the damper 440 of the own valve unit 200 to open when it has been instructed by the central controller 800 .
- the central controller 800 is configured to control the ventilator 730 to start operating when an occurrence of the refrigerant leakage in any one of the valve units 200 has been reported.
- the central controller 800 is further configured to control the damper 440 in the valve unit 200 of refrigerant leakage to open by instructing that to the corresponding unit controller 600 . More specifically, the central controller 800 is configured to perform the following operation.
- FIG. 5 is a flow chart indicating an operation performed by the central controller 800 .
- step S 2010 the central controller 800 determines whether a leakage signal has been received at the central controller 800 that was transmitted from one of the unit controllers 600 .
- This leakage signal is a signal originated from the unit controller 600 in the step S 1030 of FIG. 4 . If a leakage signal has been received (S 2010 : Yes), the central controller 800 proceeds to later-mentioned step S 2030 . If a leakage signal has not been received (S 2010 : No), the central controller 800 proceeds to later-mentioned step S 2020 .
- step S 2020 the central controller 800 determines whether termination of operation has been designated. The designation may be made by a user operation, another device, or the central controller 800 itself. If termination of the operation has not been designated (S 2020 : No), the central controller 800 goes back to step S 2010 to repeat the above determination step. If termination of the operation has been designated (S 2020 : Yes), the central controller 800 terminates its operation.
- step S 2030 the central controller 800 obtains the unit ID indicated by the received leakage signal from the leakage signal.
- This unit ID indicates the originator of the leakage signal, i.e. the valve unit 200 of refrigerant leakage. Thereby, the central controller 800 can identify the valve unit 200 of refrigerant leakage.
- step S 2050 the central controller 800 transmits, to at least the originator of the received leakage signal, a damper open command designating the originator as the valve unit 200 which should open its damper 440 .
- the central controller 800 may make this designation by using the unit ID of the originator.
- the damper open command may be directly sent to the unit controller 600 of the valve unit 200 of refrigerant leakage or relayed to it in series by the unit controller or controllers 600 .
- the central controller 800 terminates its operation. It can be said that the central controller 800 transmits the damper open command to the damper 440 of the valve unit 200 of refrigerant leakage via the corresponding unit controllers 600 by step S 2050 and step S 1120 of FIG. 4 .
- the central controller 800 may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to the central controller 800 .
- the alarm information indicates the valve unit 200 of refrigerant leakage by outputting the unit ID of the valve unit 200 of refrigerant leakage or other information from which the valve unit 200 of refrigerant leakage can be identified, e.g. information indicating the location of the valve unit 200 .
- Step S 2040 may be performed before step S 2030 , and step S 2050 may also be performed before step S 2040 . Yet, it is preferable to start operation of the ventilator 730 before opening the corresponding damper 440 .
- the central controller 800 may control the timing of transmission of the damper open command such that the corresponding damper 440 opens only when the performance of the ventilator 730 has reached a level high enough to prevent the internal air in the corresponding casing 400 from outflowing through the first opening 420 even if the damper 440 is opened.
- the central controller 800 can control the ventilator 730 to start operating and control the damper 440 in the valve unit 200 of refrigerant leakage to open in cooperation with the unit controllers 600 .
- the air conditioning system 100 includes a plurality of the multi branch selectors 300 and has the safety system 700 .
- the safety system 700 includes a plurality of the casings 400 accommodating the multi branch selectors 300 , respectively, and each provided with the refrigerant leakage detector 500 .
- the safety system 700 also includes a plurality of individual ducts 710 which function as the connection structure connecting the internal spaces 401 of the casings 400 via the second openings 430 thereof.
- the safety system 700 further includes the shared duct 720 and the ventilator 730 as the discharge structure connected to the connection structure.
- the discharge structure is configured to, when an occurrence of the refrigerant leakage has been detected, configured to discharge air from the internal space 401 of the casing 400 in which the refrigerant leakage has occurred.
- the safety system 700 can properly and promptly detect this refrigerant leakage, and discharge the air in the casing 400 covering the multi branch selector to the external space to decrease the concentration of the leaked refrigerant in the internal space 401 of the casing 400 .
- the air in the other casing or casings 400 are not discharged.
- the air volume capacity required of the ventilator 730 can be decreased, and thereby the dimension of the ventilator 730 and/or the number of the ventilator 730 can be reduced.
- the unit controllers 600 are serially connected to the central controller 800 .
- all or part of the unit controllers 600 may be individually connected to the central controller 800 via individual communication paths.
- the central controller 800 can distinguish the unit controller 600 from the other unit controller or controllers 600 by the individual communication path, and transmit the damper open command appropriately just by simply responding to the sender of the leakage signal.
- a leakage signal indicates the unit ID of the valve unit 200 in which a refrigerant leakage has occurred. Yet, if the unit controller 600 is configured to record transmission of a leakage signal and identify a damper open command as a response to the transmitted leakage signal only when the damper open command has been received within a predetermined time of the transmission, a leakage signal need not necessarily indicate any unit ID. If the central controller 800 and the unit controllers 600 communicate with each other by using different timeslots allocated to the unit controllers 600 , a leakage signal need not necessarily indicate any unit ID, either.
- the unit controller 600 may control the damper 440 of the own valve unit 200 to open when the unit controller 600 has received detection result information indicating a refrigerant leakage in the own valve unit 200 has occurred.
- the central controller 800 need not transmit a damper open command to the unit controller 600 .
- the unit controller 600 may control the damper 440 to open when a predetermined time has lapsed after transmitting the leakage signal, such that the damper 440 opens after the ventilator 730 started operating.
- connection route of the communication path 801 is not limited to the route shown FIG. 3 .
- all or part of the unit controllers 600 and the ventilator 730 may be directly connected to the central controller 800 via individual wired/wireless communication paths.
- the internal spaces 401 of the casings 400 are connected to each other in parallel.
- the internal spaces 401 of the casings 400 are connected to each other in series.
- a safety system according to the second embodiment may also be applied to an air conditioning system having the same configuration as the air conditioning system of the first embodiment.
- the configuration of each of the valve units of the safety system according to the second embodiment may be the same as that of the first embodiment.
- the same reference signs as the first embodiment are appended to elements and steps which are substantially the same as those of the first embodiment, and the explanations thereof are omitted.
- FIG. 6 is a schematic configuration diagram of a safety system according to the second embodiment.
- the safety system 700 a of the air conditioning system 100 (see FIG. 1 ) according to the second embodiment comprises the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 , first and second connecting ducts 740 a _ 1 , 740 a _ 2 , a shared duct 720 a , the ventilator 730 , and a central controller 800 a .
- the safety system 700 a does not have the individual ducts 710 of the first embodiment.
- first and second connecting ducts 740 a _ 1 , 740 a _ 2 form a connection structure which connects the first to third internal spaces 401 _ 1 , 401 _ 2 , 401 _ 3 via the first openings 4201 , 4202 and the second openings 4302 , 4303 .
- the shared duct 720 a is connected to the second opening 430 _ 1 of the casing 400 _ 1 of the first valve unit 200 _ 1 .
- the ventilator 730 is disposed to the shared duct 720 a at or close to one end (hereinafter referred to as “the second end”) of the shared duct 720 , and configured to draw air in the shared duct 720 a towards the second end. It is preferable that the second end of the shared duct 720 a is open to an outdoor space. It is also preferable that the ventilator 730 is disposed at the second end as shown in FIG. 6 .
- the static pressure capacity of the ventilator 730 of the second embodiment may be different from the ventilator 730 of the first embodiment.
- the shared duct 720 a and the ventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from the internal spaces 401 of the casings 400 when all the dampers 440 are open.
- the central controller 800 a is configured to control the ventilator 730 to start operating similarly to the first embodiment. Meanwhile, the central controller 800 a is configured to control the dampers 440 of all the valve units 200 to open.
- FIG. 7 is a flow chart indicating an operation performed by the central controller 800 a.
- step S 2050 a the central controller 800 a transmits a damper open command to all the valve units 200 . More specifically, the central controller 800 a transmits a damper open command designating all the valve units 200 including the originator of the leakage signal and serially connected to this originator. The central controller 800 a may make this designation by using the unit IDs of the valve units 200 . Then, the central controller 800 terminates its operation. The central controller 800 a may output alarm information and/or control the timing of transmission of the damper open command as mentioned in the first embodiment.
- an air path AP can be formed that extends from an external space outside the casing 400 _ 3 of the third valve unit 200 _ 3 to the ventilator 730 .
- This air path AP passes through the first opening 420 _ 3 , the internal space 401 _ 3 , and the second opening 430 _ 3 of the third valve unit 2003 , the second connecting duct 740 a _ 2 , the first opening 420 _ 2 , the internal space 401 _ 2 , and the second opening 430 _ 2 of the second valve unit 200 _ 2 , the first connecting duct 740 a _ 1 , the first opening 420 _ 1 , the internal space 401 _ 1 , and the second opening 430 _ 1 of the first valve unit 200 _ 1 , and the shared duct 720 a .
- the ventilator 730 If the ventilator 730 operates in this state, the air in the internal spaces 401 of the casings 400 of the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 are discharged by the suction force of the ventilator 730 .
- the air conditioning system 100 includes a plurality of the multi branch selectors 300 and has the safety system 700 a .
- the safety system 700 a includes a plurality of the casings 400 accommodating the multi branch selectors 300 , respectively, and each provided with the refrigerant leakage detector 500 .
- the safety system 700 a also includes a plurality of connecting ducts 740 a which function as the connection structure connecting the internal spaces 401 of the casings 400 via the first openings 420 and second openings 430 thereof.
- the safety system 700 a further includes the shared duct 720 a and the ventilator 730 as the discharge structure connected to the connection structure.
- the discharge structure is configured to, when an occurrence of the refrigerant leakage has been detected, discharge air from the internal spaces 401 of all the casings 400 including the casing 400 in which the refrigerant leakage has occurred.
- the safety system 700 a can properly and promptly detect this refrigerant leakage, and discharge the air in the casing 400 covering the multi branch selector 300 to the external space to decrease the concentration of the leaked refrigerant in the internal space 401 of the casing 400 .
- the ventilator 730 is connected to one of the casings 400 via the shared duct 720 a .
- the shared duct 720 a with short length and the ventilator 730 may be integrated as a single element. If one of the casings has a part exposed to the outdoor space, such a single element may be disposed in this part.
- a leakage signal indicates the originator of leakage signal by the unit ID of the valve unit 200 in which a refrigerant leakage has occurred, and the central controller 800 a identifies the valve unit 200 of refrigerant leakage.
- a leakage signal need not necessarily indicate the originator of leakage signal much less the unit ID, and the central controller 800 a need not necessarily identify the valve unit 200 of refrigerant leakage.
- connection route of the communication path 801 is not limited to the route shown FIG. 6 .
- all or part of the unit controllers 600 and the ventilator 730 may be directly connected to the central controller 800 a via individual wired/wireless communication paths.
- a safety system according to the third embodiment may be applied to an air conditioning system having the same configuration as the air conditioning systems of the first and second embodiments.
- the configuration of each of valve units of the safety system according to the third embodiment may be the same as that of the first and second embodiments.
- the same reference signs as the first and second embodiments are used to elements and steps which are substantially the same as those of the first and second embodiments, and the explanations thereof are omitted.
- FIG. 8 is a schematic configuration diagram of the safety system according to the third embodiment.
- the safety system 700 b of the air conditioning system 100 (see FIG. 1 ) according to the third embodiment comprises the first to third valve units 200 _ 1 , 200 _ 2 , 200 _ 3 , the first and second individual ducts 7101 , 7102 , the second connecting duct 740 a _ 2 , a shared duct 720 b , the ventilator 730 , and a central controller 800 b .
- the safety system 700 b does not have the third individual duct 710 _ 3 of the first embodiment and the first connecting duct 740 a _ 1 of the second embodiment.
- the first individual duct 710 _ 1 connects the second opening 430 _ 1 of the casing 400 _ 1 of the first valve unit 200 _ 1 to the shared duct 720 b .
- the second individual duct 710 _ 2 connects the second opening 430 _ 2 of the casing 400 _ 2 of the second valve unit 200 _ 2 to the shared duct 720 b .
- the second connecting duct 740 a _ 2 connects the second opening 430 _ 3 of the casing 400 _ 3 of the third valve unit 200 _ 3 to the first opening 4202 of the casing 400 _ 2 of the second valve unit 200 _ 2 .
- first and second individual ducts 7101 , 710 _ 2 and the second connecting duct 740 a _ 2 form a connection structure which connects the first to third internal spaces 401 _ 1 , 401 _ 2 , 401 _ 3 via the first opening 4202 and the second openings 430 _ 1 , 430 _ 2 , 430 _ 3 .
- the ventilator 730 is disposed to the shared duct 720 b at or close to one end (hereinafter referred to as “the second end”) of the shared duct 720 b , and configured to draw air in the shared duct 720 b towards the second end. It is preferable that the ventilator 730 is disposed at the second end as shown in FIG. 8 .
- the static pressure capacity of the ventilator 730 may be different from the ventilators 730 according to the first and second embodiments.
- the shared duct 720 b and the ventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from the internal space 401 _ 1 of the casing 400 _ 1 of the first valve unit 200 _ 1 when the damper 440 _ 1 of the first valve unit 200 _ 1 is open, and discharge air from the internal spaces 4012 , 401 _ 3 of the casings 400 _ 2 , 400 _ 3 of the second and third valve units 200 _ 2 , 200 _ 3 when both the dampers 440 _ 2 , 440 _ 3 of the second and third valve units 200 _ 2 , 200 _ 3 are open.
- the position, the connection to the other elements, and the physical configuration of the central controller 800 b may be the same as those of the central controller 800 according to the first embodiment.
- the central controller 800 b is also configured to perform basically the same operation as the central controller 800 according to the first embodiment.
- the central controller 800 b controls the damper or dampers 440 of all or part of the valve units 200 to be open when the ventilator 730 operates due to an occurrence of the refrigerant leakage.
- the central controller 800 b has a grouping table which defines the relationship between each of the valve units 200 and dampers 440 to be opened when a refrigerant leakage has occurred in the valve unit 200 .
- the central controller 800 b is configured to determine the valve unit 200 which should open its damper 440 based on the grouping table.
- FIG. 9 is the grouping table used by the central controller 800 b.
- the grouping table 910 b associates a destination 912 b of a damper open command with each of the valve units 200 as an originator 911 b of a leakage signal with the valve unit or units 200 .
- the destination 912 b is the valve unit or units 200 in which the damper or dampers 440 should be opened when a refrigerant leakage has occurred in the valve unit 200 as the originator 911 b.
- the grouping table 910 b indicates groups of the valve units 200 .
- the internal spaces 401 of the casings 400 are connected to the ventilator 730 in series. Between the different groups, the internal spaces 401 of the casings 400 are connected to the ventilator 730 in parallel.
- the valve units 200 may be defined in the grouping table 910 b by their unit IDs.
- the grouping table 910 b is stored in the central controller 800 b in advance.
- the central controller 800 b may accept a manually setting of the grouping table 910 b.
- the central controller 800 b performs substantially the same steps as steps S 2010 to S 2050 of FIG. 5 . Yet, in step S 2030 or S 2050 , the central controller 800 b determines the valve unit 200 which should open its damper 440 based on the originator 911 b of the received leakage signal and the grouping table 910 b . Thus, when the refrigerant leakage has occurred in the first valve unit 200 _ 1 for instance, the central controller 800 b transmits a damper open command designating the first valve unit 200 _ 1 .
- the ventilator 730 draws air from the internal space 401 _ 1 of the first valve unit 200 _ 1 , but not air from the internal spaces 401 _ 2 , 4013 of the second and third valve units 200 _ 2 , 200 _ 3 .
- the air conditioning system 100 includes the safety system 700 b in which the casings 400 serially connected to each other are further connected to the other casing 400 in parallel. Even with such a connection structure with a complicated configuration, it is possible to discharge air from the internal space 401 of the casing 400 in which the refrigerant leakage has occurred, while reducing static pressure capacity required of the ventilator 730 .
- the modifications mentioned in the first and second embodiments may be applied to a safety system 700 b according to the third embodiment. It should be noted that the grouping table 910 b and the determination of the valve unit 200 to open its damper 440 based on the grouping table 910 b mentioned above may also be applied to the first and second embodiments.
- connection route of the communication path 801 is not limited to the route shown FIG. 8 .
- all or part of the unit controllers 600 and the ventilator 730 may be directly connected to the central controller 800 b via individual wired/wireless communication paths.
- the second openings 430 _ 2 , 430 _ 3 of the second and third valve units 200 _ 2 , 200 _ 3 may be connected in parallel by a branched duct.
- the branched duct functions as both the individual ducts 7102 , 710 _ 3 of the first embodiment and the connecting ducts 740 a _ 1 , 740 a _ 2 of the second embodiment.
- the central controller 800 b is configured to open all the damper or dampers 440 existing on a line which extends from the ventilator 730 , passes through the internal space 401 of the casing 400 with refrigerant leakage, and reaches the external space of the casing 400 . It is preferable that the central controller 800 b keeps the other damper or dampers closed.
- a safety system according to the fourth embodiment may be applied to an air conditioning system having the same configuration as the air conditioning systems of the first to third embodiments.
- the configuration of each of valve units of the safety system according to the fourth embodiment may be the same as that of the first to third embodiments.
- the same reference signs as the first to third embodiments are used to elements and steps which are substantially the same as those of the first to third embodiments, and the explanations thereof are omitted.
- FIG. 10 is a schematic configuration diagram of the safety system according to the fourth embodiment.
- the safety system 700 c of the air conditioning system 100 (see FIG. 1 ) according to the fourth embodiment comprises a first section 701 c _ 1 , a second section 701 c _ 2 , and a central controller 800 c.
- the first section 701 c _ 1 includes the first and second valve units 200 _ 1 , 200 _ 2 , the first and second individual duct 710 _ 1 , 7102 , the first shared duct 720 _ 1 , and the first ventilator 730 _ 1 .
- the number of the valve units 200 in each section 701 c is not limited to two, and may be one, three, or more.
- the first and second valve units 200 _ 1 , 200 _ 2 are connected to each other in parallel and commonly connected to the first shared duct 720 _ 1 via the first and second individual duct 710 _ 1 , 710 _ 2 .
- the unit controllers (not shown in FIG. 10 , see FIG. 3 ) of the first and second valve units 200 _ 1 , 200 _ 2 and the first ventilator 730 _ 1 are connected to the central controller 800 c by the communication path 801 .
- the second section 701 c _ 2 includes the third and fourth valve units 200 _ 3 , 200 _ 4 , the connecting duct 740 a , the second shared duct 7202 , and the second ventilator 730 _ 2 .
- the third and fourth valve units 200 _ 3 , 200 _ 4 are connected to each other via the connecting duct 740 a and connected to the second shared duct 720 _ 2 in series.
- the unit controllers (not shown in FIG. 10 , see FIG. 6 ) of the third and fourth valve units 200 _ 3 , 200 _ 4 and the second ventilator 730 _ 2 are connected to the central controller 800 c by the communication path 801 .
- the position, the connection to the other elements, and the physical configuration of the central controller 800 c may be the same as those of the central controller 800 b according to the third embodiment.
- the central controller 800 c is also configured to perform basically the same operation as the central controller 800 b according to the third embodiment.
- the central controller 800 c controls the damper or dampers 440 (not shown in FIG. 10 , see FIGS. 3 and 6 ) of all or part of the valve units 200 to be open when the ventilator 730 operates due to an occurrence of the refrigerant leakage.
- the central controller 800 c determines the valve unit 200 which should open its damper 440 based on the grouping table similarly to the central controller 800 b of the third embodiment.
- the central controller 800 c uses a different type of a grouping table to further determine the ventilator which should start operating. More specifically, the central controller 800 c is configured to control the ventilator of only the section in which a refrigerant leakage has occurred to start operating.
- FIG. 11 is a grouping table used by the central controller 800 c.
- the grouping table 910 c associates, in addition to the destination or destinations 912 b of a damper open command, a ventilator 913 c which should operate with each of the valve units 200 as an originator 911 b of a leakage signal.
- the grouping table 910 c indicates the sections 701 c .
- the internal spaces 401 of the valve units 200 (not shown in FIG. 10 , see FIG. 2 ) are connected to the same ventilator, but not connected to the ventilator of the other section.
- the ventilators may be defined in the grouping table 910 c by their ventilator IDs.
- the unit ID “U1” of the first valve unit 200 _ 1 as the originator 911 b the unit ID “U1” of the first valve unit 200 _ 1 as the destination 912 b and a ventilator ID “F1” of the first ventilator 730 _ 1 as the ventilator 913 c to operate are associated.
- the unit ID “U2” of the second valve unit 200 _ 2 as the originator 911 b the unit ID “U2” of the second valve unit 200 _ 2 as the destination 912 b and a ventilator ID “F1” of the first ventilator 730 _ 1 as the ventilator 913 c to operate are associated.
- the grouping table 910 c is stored in the central controller 800 c in advance.
- the central controller 800 c may accept a manually setting of the grouping table 910 c.
- the structure of the grouping table 910 c is not limited to that shown in FIG. 11 .
- the grouping table 910 c may simply define groups of the valve units 200 such that the valve units 200 connected to the same ventilator 730 in series by the connection structure form a group, and associates the group with the corresponding ventilator 730 .
- the single valve unit 200 to which no other valve unit 200 is connected in series with respect to the ventilator 730 by the connection structure may also form a group.
- Each group may be defined by using identifications of the unit controllers 600 .
- the central controller 800 c performs substantially the same steps as steps S 2010 to S 2050 of FIG. 5 . Yet, the central controller 800 c determines in step S 2030 or S 2040 the ventilator which should start operating based on the originator of the received leakage signal and the grouping table 910 c , and determines in step S 2030 or S 2050 the valve unit or units 200 each of which should open its damper 440 based on the originator of the received leakage signal and the grouping table 910 c.
- the central controller 800 c transmits a ventilator start command to the first ventilator 730 _ 1 for starting its operation, and transmits a damper open command designating the first valve unit 200 _ 1 .
- the ventilator start command may designate the ventilator ID of the ventilator which should start operating.
- the air conditioning system 100 includes the safety system 700 c which is sectioned into a plurality of sections 701 c controlled by the common central controller 800 c .
- the central controller 800 c is configured to, when a refrigerant leakage in any one of the valve units 200 has occurred, control the ventilator of only the section 701 c in which the refrigerant leakage has occurred to start operating, and control only the damper or dampers 440 which should be opened in order to discharge air from the valve unit 200 of refrigerant leakage.
- the air discharge can be performed appropriately while reducing electricity consumption.
- connection route of the communication path 801 is not limited to the route shown FIG. 10 .
- the third and fourth valve units 200 _ 3 , 2004 and the second ventilator 730 _ 2 of the second section 701 c _ 2 may be connected to the central controller 800 c by another communication path 801 independently from the first section 701 c _ 1 , or indirectly connected to the central controller 800 c via the unit controller or controllers 600 of the first section 701 c _ 1 . All or part of the unit controllers 600 and the ventilators 730 may be directly connected to the central controller 800 c via individual wired/wireless communication paths.
- the connection routes of the casings 400 of the valve units 200 by ducts are also not limited to the routes shown in FIG. 10 .
- the valve unit 200 may have a configuration including the heatsource-side liquid pipe portion 310 , the utilization-side liquid pipe portions 311 , the low-pressure gas pipe portion 320 , the low-pressure gas sub pipes 321 , the high-pressure gas pipe portion 340 , the high-pressure gas sub pipes 341 , the utilization-side gas pipe portions 330 , the low-pressure gas control valves 361 , and the high-pressure gas control valves 362 , but not including all or part of the sets of the bypass pipe 351 , the refrigerant heat exchanger 352 , and the expansion mechanism 363 . All or part of the gas shut-off valves 365 may be further omitted.
- the air conditioning system 100 may have a heat pump system with a so-called two-pipe configuration.
- the piping accommodated in the casing 400 would not be the multi branch selector 300 .
- the valve unit 200 has at least a liquid refrigerant pipe portion, a gas refrigerant pipe portion, a liquid control valve disposed in the liquid refrigerant pipe portion, and a gas control valve disposed in the gas refrigerant pipe portion.
- Each of the liquid control valve and the gas control valve may be any type of valve for controlling flow of refrigerant in the corresponding pipe portion.
- any one of the safety systems 700 , 700 a , 700 b , 700 c may include the valve unit 200 d as shown in FIG. 12 instead of the valve unit 200 of FIG. 2 .
- the valve unit 200 d as a modification of the present embodiment does not necessarily have the high-pressure gas pipe portion 340 , the low-pressure gas sub pipes 321 , the high-pressure gas sub pipes 341 , the bypass pipes 351 , the refrigerant heat exchangers 352 , the low-pressure gas control valves 361 , the high-pressure gas control valves 362 , and the expansion mechanisms 363 .
- any one of the above-mentioned valve units may have a configuration in which the heatsource-side liquid pipe portion 310 and the gas pipe portion or portions 320 , 340 are not branched towards two or more of the utilization-side units 120 of the air conditioning system 100 but directed towards only one among the utilization-side units 120 .
- each valve disposed in the refrigerant pipe portions within the casing 400 would be a leakage point of refrigerant, and thus the safety regarding refrigerant leakage should be improved.
- the casing 400 of any one of the above embodiments and modifications may comprise a plurality of casing parts which are attachable to and detachable from each other.
- the casing parts may be structured such that each of the pipe apertures 410 is formed between two or more of the adjoining casing parts. Thereby, each extending pipe can easily be fitted into the corresponding pipe aperture 410 when the casing parts are assembled.
- the method for assembling the safety system 700 / 700 a / 700 b / 700 c may include steps of: arranging, for each of the valve units 200 / 200 d , the corresponding casing parts around at least the liquid control valve and the gas control valve of the valve units 200 / 200 d ; fixing, for each of the valve units 200 / 200 d , the corresponding casing parts to each other; disposing, for each of the valve units 200 / 200 d , the refrigerant leakage detector 500 ; arranging the connection structure so as to connect the internal spaces 401 of the casings 400 ; and connecting the discharge structure to the connection structure or one of the casings 400 .
- the casing 400 can be retrofitted to existing valves of a heat pump system.
- the insulators 450 may also be applied to the gap between the adjoining casing parts.
- the unit controller 600 of each valve unit 200 may have further functions.
- the unit controller 600 may be further configured to, when a refrigerant leakage in any of the utilization-side piping sections has occurred, control the liquid shut-off valve 364 and the gas shut-off valve 365 (see FIG. 2 ) defining the utilization-side piping section to close.
- the utilization-side piping section can be zoned from other parts of the heat pump circuit.
- the unit controller 600 may shut-down the air conditioning system 100 by, for instance, stopping the operation of the compressor in the heatsource-side unit and the operations of the utilization-side units 120 . Thereby, it is possible to prevent as much as possible the refrigerant from leaking out further.
- the position, the orientation, and the number of the ventilator 730 are not limited to those according to the first to fourth embodiments.
- the ventilator 730 may be arranged so as to blow air towards the internal space 401 of the casing 400 in which a refrigerant leakage has occurred. Thereby, it is also possible to discharge the air containing refrigerant from the corresponding first opening 420 with the damper 440 open.
- an additional ventilator may be provided to the individual duct 710 , the connecting duct 740 a , and/or the shared duct 720 , 720 a between the ventilator 730 and any one of the internal spaces 401 to boost the suction force.
- the damper 440 for the first opening 420 is not necessarily required. If the isolation of the internal space 401 of the casing 400 is sufficient without any specific insulators 450 , such insulators 450 may be omitted.
- All or part of the unit controllers 600 may be integrated to the central controller 800 / 800 a / 800 b / 800 c .
- the central controller 800 / 800 a / 800 b / 800 c may compare the detection values Vs with the detection value threshold Vth.
- all or part of the central controller 800 / 800 a / 800 b / 800 c may be integrated to the unit controllers 600 .
- each of the unit controller 600 may determine whether to open the damper 440 of the own valve unit 200 .
- the refrigerant leakage detector 500 is not required. In this case, the operations shown in FIGS. 4 , 5 , and 7 are not necessarily required. Moreover, if ventilation of the internal air via the connection structure is induced by natural convection or an air flow caused by an external mechanism, the ventilator 730 is not necessarily required.
- the piping accommodated in the casing 400 is not limited to the multi branch selector 300 .
- other elements which are potential refrigerant leakage points such as the compressor of the heatsource-side unit 110 , may be accommodated in the casing 400 .
- the casing 400 of the compressor may also be connected to the other casing or casings 400 by the connection structure and provided with the discharge structure in the same manner as the casings 400 of a plurality of the multi branch selectors 300 as explained above.
- an air conditioning system is explained which can further improve safety regarding a refrigerant leakage from the compressor and its surrounding elements.
- a space surrounding a compressor unit is further subjected to the detection of refrigerant leakage and the discharge of air.
- the air conditioning system according to the fifth embodiment is similar to the air conditioning system 100 according to the first embodiment.
- the configuration of the safety system is different from that of the first embodiment.
- the piping configuration may also be different from that of the first embodiment.
- FIG. 13 is a schematic configuration diagram of an air conditioning system according to the fifth embodiment.
- the air conditioning system 100 h has the heatsource-side unit 110 h , the valve unit 200 h , and the utilization-side units 120 which are connected by refrigerant pipes as with the first embodiment.
- the heat pump system of the air conditioning system 100 h may have the three-pipe configuration like the configuration shown in FIG. 1 .
- the air conditioning system 100 h may have two or more valve units 200 h like the configuration shown in FIG. 1 .
- the heatsource-side unit 110 h of the present embodiment is separated into two separate units of a HEX unit (a heat exchanger unit) 101 h and a compressor unit 111 h.
- the compressor unit 111 h has a compressor 112 h configured to compress first refrigerant.
- the compressor unit 111 h may further have a switching mechanism 113 h configured to switch the state of the heat pump system between a cooling operation mode and a heating operation mode.
- a discharge port of the compressor 112 h is connected to a piping leading to a later-mentioned outdoor heat exchanger, and a suction port of the compressor 112 h is connected to a piping leading to later-mentioned indoor heat exchangers.
- the HEX unit 101 h has an outdoor heat exchanger 102 h which is configured to allow air to pass therethrough and allow the first refrigerant to flow therein to exchange heat between the air and the first refrigerant.
- the outdoor heat exchanger 102 h is connected to one of the discharge port and the suction port of the compressor 112 h via part of the gas refrigerant pipe 132 .
- the outdoor heat exchanger 102 h is also connected to the later-mentioned indoor heat exchangers via the liquid refrigerant pipe 131 , the heatsource-side liquid pipe portion 310 and the utilization-side liquid pipe portions 311 of the valve unit 200 h , and the utilization-side liquid refrigerant pipe 151 .
- the outdoor heat exchanger 102 h may be provided with a fan to facilitate flow of the air.
- Each of the utilization-side unit 120 has an indoor heat exchanger 122 h which corresponds to the utilization-side heat exchanger mentioned in the first embodiment.
- Each of the indoor heat exchangers 122 h is connected to the outdoor heat exchanger 102 h via the above-mentioned piping, and configured to allow air to pass therethrough and allow the first refrigerant to flow therein to exchange heat between the air and the first refrigerant.
- Each of the indoor heat exchangers 122 h is further connected to the other one the discharge port and the suction port of the compressor 112 h via the utilization-side gas refrigerant pipe 152 , the utilization-side gas pipe portion 330 and the low-pressure gas pipe portion 320 of the valve unit 200 h , and another part of the gas refrigerant pipe 132 .
- Each of the indoor heat exchangers 122 h may be provided with a fan to facilitate flow of the air.
- the air conditioning system 100 h has first connection pipes connecting the HEX unit 101 h and the compressor unit 111 h such that the first refrigerant circulates therebetween, and second connection pipes connecting the compressor unit 111 h , the valve unit 200 h , and the utilization-side units 120 such that the first refrigerant circulates between the compressor unit 111 h and the utilization-side units 120 via the valve unit 200 h .
- the HEX unit 101 h , the compressor unit 111 h , the valve unit 200 h , and each of the utilization-side units 120 are connected via refrigerant pipes so as to form a heat pump circuit using the first refrigerant.
- first refrigerant may be CO2 refrigerant (carbon oxide refrigerant), R290 refrigerant (propane), HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf, but is not limited to these refrigerants.
- the HEX unit 101 h is installed in a first space 931 h which is an outdoor space or a space through which outdoor air is allowed to pass.
- the outdoor heat exchanger 102 h can be continuously supplied with drafts of outdoor air to effectively release heat from or absorb heat into the first refrigerant.
- the utilization-side units 120 are installed in a target space 933 h which is to be air conditioned.
- the indoor heat exchangers 122 h can perform a heat exchange between the first refrigerant and air in the target space 933 h to cool or warm it.
- the utilization-side units 120 need not necessarily be installed in the target space 933 h . If an outlet port of each of the utilization-side units 120 for supplying air-conditioned air leads to the target space 933 h via a duct or the like, the utilization-side units 120 may be disposed outside the target space 933 h.
- the compressor unit 111 h and the valve unit 200 h are installed in a second space 932 h which is different from any of the first space 931 h and the target space 933 .
- the second space 932 h is substantially isolated in normal times from at least the first space 931 h and the target space 933 h , and ventilation of the second space 932 h is controlled independently from that of the first space 931 h and the target space 933 h.
- the target space 933 is a room of a building to which the air conditioning system 100 h is installed such as an office room.
- the utilization-side units 120 are so-called indoor units.
- the first space 931 h is a room of the same building which has an air passage or passages freely leading to the outdoor space, or an outdoor space outside the building such as a space of a roof floor of the building.
- the second space 932 h is another room of the same building such as a machine room, a computer room, or a warehouse.
- the safety system of the present embodiment includes a ventilation control structure for controlling the ventilation environment of the second space 932 h .
- a configuration is explained in which the ventilation control structure causes a forced ventilation of the second space 932 h when a refrigerant leakage has occurred in the second space 932 h .
- the ventilation control structure includes a discharge structure that operates to discharge air from the second space 932 h when concentration of the first refrigerant in the second space 932 h has increased.
- FIG. 14 is a schematic configuration diagram of the safety system of the air conditioning system 100 h.
- the second space 932 h is defined as a room by a building structure 934 h .
- the internal space of the building structure 934 h is the second space 932 h .
- This building structure 934 h may also be regarded as part of the ventilation control structure.
- the building structure 934 h includes a floor, a ceiling facing the floor, and at least one wall which connects the floor and the ceiling and surrounds a space between the floor and a ceiling.
- the building structure 934 h may further include a door arranged in the floor, the ceiling, or the wall.
- the building structure 934 h is formed with a first airflow passage 935 h and a second airflow passage 936 h between the second space 932 h and an outer space outside of the second space 932 h . This outer space is preferably the outdoor space.
- the safety system 700 h includes a refrigerant leakage detector (a first leakage detector) 500 disposed in the second space 932 h , and a discharge structure.
- the discharge structure includes a damper 440 disposed to the first airflow passage 935 h , a ventilator 730 disposed to the second airflow passage 936 h , and a central controller 800 h .
- any of the refrigerant leakage detector 500 and the central controller 800 h may be part of the compressor unit 111 h or the valve unit 200 h .
- the configurations of the ventilator 730 , the damper 440 , and the refrigerant leakage detector 500 may be the same as those of the first to fourth embodiments.
- the ventilator 730 , the damper 440 , and the refrigerant leakage detector 500 are connected to the central controller 800 h via a communication path 801 by means of a wired and/or wireless communication.
- the refrigerant leakage detector 500 is configured to detect at least a concentration of the first refrigerant in air.
- the ventilator 730 is configured to draw air from the second space 932 h towards an external space which is different from any of the target space 933 h and the second space 932 h via the second airflow passage 936 h .
- the damper 440 may be a check air damper, and configured to keep the first airflow passage 935 h closed in normal times. Yet, under the control of the central controller 800 h as mentioned later, the damper 440 is configured to open the first airflow passage 935 h when the ventilator 730 is in operation.
- the first airflow passage 935 h works as an intake port of an external air for promoting the ventilation of the second space 932 h.
- each of the first airflow passage 935 h and the second airflow passage 936 h is formed in an exterior wall of the building which also defines the second space 932 h .
- the building structure 934 h is configured such that its internal space (i.e. second space 932 h ) is substantially closed in the normal times.
- the central controller 800 h is configured to, when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold (e.g. when the detected concentration has reached to the first detection value threshold), control the ventilator 730 to operate, and also control the damper 440 to open.
- a first detection value threshold e.g. when the detected concentration has reached to the first detection value threshold
- the central controller 800 h corresponds to the central controller 800 of the first embodiment and may have the same hardware configuration as the central controller 800 .
- the central controller 800 h performs an operation similar to the operations by the unit controller 600 and the central controller 800 of the first embodiment. Yet, in the present embodiment, the operation is made simpler.
- FIG. 15 is a flow chart indicating the operation performed by the central controller 800 h .
- steps S 3010 h , S 3020 h , S 3030 h , S 3040 h , and S 3050 h correspond to steps S 1010 , S 1020 , S 2040 , S 1120 , S 1110 explained in the first embodiment, respectively.
- step S 3020 h the central controller 800 h compares the first detection value Vs 1 acquired and the first detection value threshold Vth 1 , and determines whether the first detection value Vs 1 is less than the first detection value threshold Vth 1 .
- the central controller 800 h may obtain a moving average value of the detection values Vs 1 in a certain time length to use the moving average value as the first detection value Vs 1 which is compared with the first detection value threshold Vth 1 .
- the first detection value threshold Vth 1 is stored in the central controller 800 h in advance.
- the first detection value threshold Vth 1 may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the first detection value threshold Vth 1 is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the refrigerant used.
- LFL Lower Flammability Limit
- step S 3030 h the central controller 800 h transmits a ventilator start command to the ventilator 730 to control the ventilator 730 to start operating.
- the central controller 800 h may control the operation of the ventilator 730 by controlling a supply of electricity thereto.
- the central controller 800 h controls the damper 440 to open.
- the central controller 800 h controls the state of the damper 440 by controlling a supply of electricity thereto.
- the central controller 800 h may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to the central controller 800 h.
- step S 3030 h and step S 3040 h may be reversed.
- the damper 440 and the ventilator 730 need not necessarily be controlled directly by the central controller 800 h .
- the damper 440 may be controlled via the ventilator 730 , or the ventilator 730 may be controlled via the damper 440 .
- the state of the second space 932 h can be switched from a normal state (a first state) to an emergency state (a second state) in which a ventilation of the second space 932 h is promoted more than in the normal state.
- the ventilation of the second space 932 h can be restricted in normal times.
- the refrigerant leakage detector 500 when the occurrence of refrigerant leakage has been detected, the ventilation of the second space 932 h is started.
- the air containing the leaked refrigerant can be discharged from the second space 932 h at an early stage. Accordingly, it is possible to improve safety regarding refrigerant leakage at low cost, even in a case where the compressor 112 h should be arranged inside the building.
- the compressor unit 111 h and the valve unit 200 h may be covered by two casings which are connected in series by the connection structure and provided with the discharge structure.
- FIG. 16 is a schematic configuration diagram of a safety system according to a first variation of the fifth embodiment.
- a safety system 700 i comprises a compressor unit casing 400 _ c (a first casing) and a valve unit casing 400 _ v (a second casing) which are arranged within the second space 932 h as part of the second space 932 h .
- the compressor unit casing 400 _ c accommodates at least part of the compressor unit 111 h .
- This accommodated part includes at least the compressor 112 h .
- the valve unit casing 400 _ v accommodates at least part of the valve unit 200 h .
- This accommodated part includes at least the liquid shut-off valves 364 and the gas shut-off valves 365 .
- the compressor unit casing 400 _ c may be regarded as part of the compressor unit 111 h
- the valve unit casing 400 _ v may be regarded as part of the valve unit 200 h.
- the compressor unit casing 400 _ c and the valve unit casing 400 _ v correspond to the casings 400 according to the second embodiment, and may have the same configurations thereof.
- the compressor unit casing 400 _ c is formed with a first opening 420 _ c and a second opening 430 _ c
- the valve unit casing 400 _ v is formed with a first opening 420 _ v and a second opening 430 _ v.
- the safety system 700 i has a serial structure similar to the second embodiment.
- the safety system 700 i has a connecting duct 740 which is connected on one side to the second opening 430 _ c of compressor unit casing 400 _ c , and connected on another side to the first opening 420 _ v of the valve unit casing 400 _ v .
- the connecting duct 740 is a connection structure connecting an internal space 401 _ c of the compressor unit casing 400 _ c and an internal space 401 _ v of the valve unit casing 400 v.
- the safety system 700 i further has an intake duct 750 i which is connected on one side to the first airflow passage 935 h , and connected on another side to the first opening 420 _ c of the compressor unit casing 400 _ c .
- the intake duct 750 i connects the outer space of the second space 932 h and the internal space 401 _ c of the compressor unit casing 400 _ c .
- the first airflow passage 935 h may be regarded as part of the intake duct 750 i
- the intake duct 750 i may be regarded as part of the first airflow passage 935 h.
- the safety system 700 i also has a ventilator 730 disposed to the shared duct 720 a .
- the configurations of these may be the same as those of the shared duct 720 a and the ventilator 730 according to the second embodiment.
- any of the first airflow passage 935 h and the second airflow passage 936 h may be an opening of the building structure 934 h or a duct connected to such an opening.
- the ventilator 730 and/or the damper 440 may be mounted to the building structure 934 h , arranged inside the second space 932 h , or arranged outside the second space 932 h.
- the compressor unit casing 400 _ c and the valve unit casing 400 _ v are connected by the connecting duct 740 in series with respect to the shared duct 720 .
- the damper 440 disposed between the compressor unit casing 400 _ c and the valve unit casing 400 _ v is omitted. It is noted that the positions of the casing 400 _ c , 400 _ v with respect to the intake duct 750 i and the shared duct 720 a may be reversed.
- the safety system 700 i further has a compressor unit leakage detector 500 _ c which corresponds to the refrigerant leakage detector 500 according to the second embodiment.
- the compressor unit leakage detector 500 _ c is disposed in the internal space 401 _ c of the compressor unit casing 400 _ c , and may be part of the compressor unit 111 h .
- the compressor unit leakage detector 500 _ c is configured to detect at least a concentration of the first refrigerant in air.
- the safety system 700 i further has a central controller 800 i which corresponds to the unit controller 600 and the central controller 800 a according to the second embodiment, and may have the same hardware configuration as the unit controller 600 and/or the central controller 800 a .
- the central controller 800 i may be part of the compressor unit 111 h .
- the central controller 800 i may perform the operation as shown in FIG. 15 based on the detector signal outputted from the compressor unit leakage detector 500 _ c.
- the safety system 700 i may further have a valve unit leakage detector 500 _ v disposed in the internal space 401 _ c of the valve unit casing 400 _ v , which may have the same configuration as the compressor unit leakage detector 500 _ c .
- the central controller 800 i further performs the determination of step S 3020 h based on the detector signal outputted from the valve unit leakage detector 500 _ v .
- the central controller 800 i starts the ventilator 730 and open the damper 440 when a refrigerant leakage has occurred in any of the compressor unit casing 400 _ c and the valve unit casing 400 _ v .
- the detector signal of the valve unit leakage detector 500 _ v may be relayed to the central controller 800 i by the unit controller 600 of the valve unit 200 h via the communication path 801 , or directly transmitted to the central controller 800 i via the communication path 801 .
- the total volume of the internal spaces 401 _ c , 401 _ v of the casings 400 _ c , 400 _ v and internal spaces of the ducts 750 i , 740 a , 720 a between the damper 440 and the ventilator 730 can be made much smaller than the volume of the whole second space 932 h .
- both the detection of the refrigerant leakage and the discharge of the air containing the leaked refrigerant can be performed more swiftly compared with the configuration shown in FIG. 14 .
- the casings 400 _ c , 400 _ v and ducts 750 i , 740 a , 720 a can prevent or restrain refrigerant leaked from the compressor unit 111 h or the valve unit 200 h from spreading in the second space 932 h . Hence, the safety regarding refrigerant leakage can be further improved.
- the internal space 401 _ c of the compressor unit casing 400 _ c and the internal space 401 _ v of the valve unit casing 400 _ v are part of the second space 932 h but can also be regarded as a second space in which the compressor unit 111 h , the valve unit 200 h , and the compressor unit leakage detector 500 _ c are installed and which is different from any of the target space 933 h and the first space 931 h .
- the building structure 934 h need not necessarily be configured to close its internal space (i.e. second space 932 h ).
- the casings 400 _ c , 400 _ v may be connected in parallel with respect to the shared duct.
- FIG. 17 is a schematic configuration diagram of a safety system of an air conditioning system according to a second variation of the fifth embodiment.
- the safety system 700 j according to the second variation has the same configuration as the safety system 700 i of the first variation except for the structure for connecting the internal spaces 401 _ c , 401 _ v of the casings 400 _ c , 400 _ v to the external space or spaces of the second space 932 h .
- the casings 400 _ c , 400 _ v of the compressor unit 111 h and the valve unit 200 h are connected in the same manner as the casings 400 of the valve units 200 according to the first embodiment as shown in FIG. 3 .
- the safety system 700 j has a first intake duct 750 i _c which corresponds to the intake duct 750 i according to the first variation. Yet, instead of the connecting duct 740 a and the shared duct 720 a of the first variation, the safety system 700 j has a second intake duct 750 i _v, a first individual duct 710 _ 1 , a second individual duct 710 _ 2 , and a shared duct 720 b.
- the building structure 934 h is further formed with a third airflow passage 937 j between the second space 932 h and an outer space outside of the second space 932 h .
- the second intake duct 750 i _v is connected on one side to this third airflow passage 937 j , and connected on another side to the first opening 420 _ v of the valve unit casing 400 _ v .
- the second intake duct 750 i _v connects the outer space of the second space 932 h and the internal space 401 _ v of the valve unit casing 400 _ v .
- the third airflow passage 937 j may be regarded as part of the second intake duct 750 i _v
- the second intake duct 750 i _v may be regarded as part of the third airflow passage 937 j.
- the configurations and/or arrangements of the third airflow passage 937 j and the second intake duct 750 i _v may be the same as or similar to those of the first airflow passage 935 h and the first intake duct 750 i _c.
- a damper 440 is also disposed to the third airflow passage 937 j as with the first airflow passage 935 h .
- the third airflow passage 937 j may be an opening of the building structure 934 h or a duct connected to such an opening as with the first airflow passage 935 h and the second airflow passage 936 h .
- the dampers 440 disposed to the third airflow passage 937 j may also be mounted to the building structure 934 h , arranged inside the second space 932 h , or arranged outside the second space 932 h.
- the first individual duct 710 _ 1 connects the second opening 430 _ v of the valve unit casing 400 _ v to the shared duct 720 b .
- the second individual duct 710 _ 2 connects the second opening 430 _ c of the compressor unit casing 400 _ c to the shared duct 720 b .
- the first and second individual ducts 710 _ 1 , 710 _ 2 form a connection structure connecting the internal spaces 401 _ c , 401 _ v of the casings 400 _ c , 400 _ v
- the shared duct 720 b connects this connection structure and the external space of the second space 932 h .
- the ventilator 730 is disposed to the shared duct 720 b at or close to one end of the shared duct 720 b , and configured to draw air in the shared duct 720 b towards the second end.
- the configurations of these elements may be the same as those of the individual ducts 710 , the shared duct 720 b , and the ventilator 730 according to the first embodiment.
- the central 800 i may perform the operation as shown in FIG. 15 , while controlling both the dampers 440 to open in step S 3040 h upon controlling the ventilator 730 to start operating.
- each of the internal spaces 401 _ c , 401 _ v communicates with the discharge structure without being interposed by any other casing.
- the first airflow passage 935 h and the third airflow passage 937 j may be integrated to a single airflow passage.
- the dampers 440 for them may also be integrated a single damper.
- the compressor unit 111 h and the valve unit 200 h may be covered by a single casing.
- FIG. 18 is a schematic configuration diagram of a safety system of an air conditioning system according to a third variation of a fifth embodiment.
- the safety system 700 k according to the third variation has the same configuration as the safety system 700 i of the first variation except for the structure for covering compressor unit 111 h and the valve unit 200 h .
- the safety system 700 k has a casing 400 arranged within the second space 932 h , instead of the casings 400 _ c , 400 _ v and the connecting duct 740 a of the first variation, as part of the second space 932 h .
- the casing 400 accommodates at least part of the compressor unit 111 h and at least part of the valve unit 200 h . These accommodated parts include at least the compressor 112 h , the liquid shut-off valves 364 , and the gas shut-off valves 365 .
- the casing 400 corresponds to each casing 400 according to the second embodiment, and may have the same configuration thereof.
- the safety system 700 k also has a refrigerant leakage detector 500 and a central controller 800 i which correspond to the compressor unit leakage detector 500 _ c and the central controller 800 i according to the first variation, respectively.
- the refrigerant leakage detector 500 is disposed in an internal space 401 of the casing 400 .
- the central controller 800 i may perform the operation as shown in FIG. 15 based on the detector signal outputted from the refrigerant leakage detector 500 .
- the internal space 401 of the casing 400 is part of the second space 932 h but can also be regarded as a second space in which the compressor unit 111 h , the valve unit 200 h , and the refrigerant leakage detector 500 are installed and which is different from any of the target space 933 h and the first space 931 h .
- the building structure 934 h need not necessarily be configured to close its internal space (i.e. second space 932 h ).
- This third variation is suitable for the case where the compressor unit 111 h and the valve unit 200 h are arranged close to each other. With this variation, since the number of the casing 400 is decreased and the connecting duct 740 a is not required, it is possible to further reduce the installation cost of the air conditioning system.
- the air conditioning system is configured such that the same refrigerant flows through the HEX unit, the compressor unit, the valve unit, and the utilization units.
- the configurations of the safety systems (the ventilation control structures) according to the fifth embodiment and its variations may also be applied to other types of piping.
- the safety system can be applied to an air conditioning system of a cascade-type in which two or more circuits of the same or different heat mediums are formed and a heat exchange therebetween is performed.
- an air conditioning system of a cascade-type is explained.
- the air conditioning system according to the sixth embodiment is similar to the air conditioning system 100 h according to the fifth embodiment. Yet, the configuration of the piping is different from that of the fifth embodiment. This difference is explained hereinafter, and the other configurations not referred to are the same as the fifth embodiment unless otherwise indicated.
- the same reference signs as the fifth embodiment are appended to elements which are substantially the same as those of the fifth embodiment, and the explanations thereof are omitted.
- FIG. 19 is a schematic configuration diagram of the air conditioning system according to the sixth embodiment.
- the piping of the air conditioning system 100 m according to the sixth embodiment is separated into a first circuit 105 m for first refrigerant and a second circuit 106 m for second refrigerant.
- the air conditioning system 100 m has a HEX unit 101 m , a compressor unit 111 m , a valve unit 200 m , and utilization-side units 120 m which correspond to the HEX unit 101 h , the compressor unit 111 h , the valve unit 200 h , and the utilization-side units 120 according to the fifth embodiment, respectively.
- the HEX unit 101 m includes an outdoor heat exchanger 102 m corresponding to the outdoor heat exchanger 102 h of the fifth embodiment, and the compressor unit 111 m includes a compressor 112 m and a switching mechanism 113 m corresponding to the compressor 112 h and the switching mechanism 113 h of the fifth embodiment. Yet, the compressor unit 111 m according to the present embodiment further has a refrigerant heat exchanger 114 m .
- the HEX unit 101 m and the compressor unit 111 m are connected by a unit liquid refrigerant pipe 103 m and a unit gas refrigerant pipe 104 m (first connection pipes) such that the first refrigerant circulates therebetween.
- the refrigerant heat exchanger 114 m is configured to allow each of the first refrigerant and the second refrigerant to flow therein so as to exchange heat between the first refrigerant and the second refrigerant.
- the compressor 112 m , the switching mechanism 113 , the outdoor heat exchanger 102 h , the refrigerant heat exchanger 114 m , and the pipes connecting them form the first circuit 105 m which circulates the first refrigerant.
- the valve unit 200 m includes a heatsource-side liquid pipe portion 310 m , a low-pressure gas pipe portion 320 m , utilization-side liquid pipe portions 311 m , utilization-side gas pipe portions 330 m , liquid shut-off valves 364 m , and gas shut-off valves 365 m which correspond to the heatsource-side liquid pipe portion 310 , the low-pressure gas pipe portion 320 , the utilization-side liquid pipe portions 311 , the utilization-side gas pipe portions 330 , the liquid shut-off valves 364 , and the gas shut-off valves 365 according to the fifth embodiment, respectively.
- Each of the utilization-side units 120 m includes an indoor heat exchanger 122 m corresponding to the indoor heat exchanger 122 according to the fifth embodiment.
- the compressor unit 111 m , the valve unit 200 m , and the utilization-side units 120 m are connected to each other via a liquid refrigerant pipe 131 m , a gas refrigerant pipe 132 m , utilization-side liquid refrigerant pipes 151 m , and utilization-side gas refrigerant pipes 152 m corresponding to the liquid refrigerant pipe 131 , the gas refrigerant pipe 132 , the utilization-side liquid refrigerant pipes 151 , and the utilization-side gas refrigerant pipes 152 according to the fifth embodiment.
- valve unit 200 m and the utilization-side units 120 m and the refrigerant pipes 131 m , 132 m are configured to allow the second refrigerant to flow therein instead of the first refrigerant.
- the liquid refrigerant pipe 131 m and the gas refrigerant pipe 132 m are connected to the refrigerant heat exchanger 114 m of the compressor unit 111 m such that the second refrigerant circulates between the compressor unit 111 m and the utilization-side units 120 m via the valve unit 200 m .
- the air conditioning system 100 m further has a pump 116 m disposed to the liquid refrigerant pipe 131 m or the gas refrigerant pipe 132 m , preferably as part of the compressor unit 111 m .
- the pump 116 m is configured to induce a flow of the second refrigerant.
- the pump 116 m may be a compressor for compressing the second refrigerant.
- elements required for forming a heat pump circuit such as an expansion mechanism and an accumulator may also be provided to the second circuit 106 m.
- the refrigerant type of the second refrigerant is the same as or different from that of the first refrigerant.
- the “second refrigerant” may be CO2 refrigerant (carbon oxide refrigerant), R290 refrigerant (propane), HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf, but is not limited to these refrigerants.
- HFC or HFC refrigerant is used as the first refrigerant
- CO2 refrigerant is used as the second refrigerant.
- the HEX unit 101 m is installed in the first space 931 h
- the compressor unit 111 m and the valve unit 200 m are installed in the second space 932 h
- the utilization-side units 120 are installed in the target space 933 h .
- Any of the safety systems 700 h 700 i , 700 j , 700 k according to the first embodiment and its variations may be applied to the air conditioning system 100 m .
- FIG. 20 is a schematic configuration diagram of an example of a safety system of the air conditioning system 100 m.
- a safety system 700 m of the air conditioning system 100 m may have substantially the same configuration as the safety system 700 h of the fifth embodiment. Yet, instead of the refrigerant leakage detector 500 and the central controller 800 h of the fifth embodiment, the safety system 700 m has a first leakage detector 501 m , a second leakage detector 502 m , and a central controller 800 m .
- the first leakage detector 501 m may be the same as the refrigerant leakage detectors 500 _ c according to the first variation of the fifth embodiment.
- the compressor unit 111 m and the valve unit 200 m may be covered by respective casings or a single casing. If the compressor unit 111 m has a casing accommodating at least the compressor 112 m , the first leakage detector 501 m may be disposed in the casing like the first variation of the fifth embodiment.
- the second leakage detector 502 m is disposed in the second space 932 h but outside any casings of the compressor unit 111 m and the valve unit 200 m for instance.
- the second leakage detector 502 m is configured to detect at least a concentration of the second refrigerant in an air surrounding the second leakage detector 502 m , and continuously or regularly output a detector signal indicating a detection value Vs 2 to the central controller 800 m via the communication path 801 .
- the second leakage detector 502 m may be a semi-conductor gas sensor reactive to the second refrigerant.
- the second leakage detector 502 m is preferably disposed in the second space 932 h at or close to an inner bottom surface of the second space 932 h.
- the central controller 800 m corresponds to the central controller 800 i of the first variation of the fifth embodiment, and may have the same hardware configuration as the central controller 800 i . Yet, the central controller 800 m according to the present embodiment further controls the ventilator 730 to start operating when the detected concentration of the second refrigerant has been increased.
- the central controller 800 m performs all steps S 3010 h , S 3020 h , S 3030 h , S 3040 h , and S 3050 h according to the fifth embodiment shown in FIG. 15 as with the central controller 800 i of the first variation of the fifth embodiment.
- the central controller 800 m further performs operations of steps S 3021 m , S 3022 m before step S 3010 h or between step S 3020 h and step S 3050 h.
- step S 3021 m the central controller 800 m acquires the detection value as a second detection value Vs 2 from the detector signal outputted from the second leakage detector 502 m .
- the central controller 800 m may passively receive the detector signal which is continuously or regularly outputted from the second leakage detector 502 m , or actively request the second leakage detector 502 m to output the detector signal regularly.
- the obtained first detection value Vs 2 basically reflects the variation in the concentration of the second refrigerant in the second space 932 h.
- step S 3022 m the central controller 800 m compares the second detection value Vs 2 acquired and a second detection value threshold Vth 2 , and determines whether the second detection value Vs 2 is less than the second detection value threshold Vth 2 .
- the central controller 800 m may obtain a moving average value of the detection values Vs 2 in a certain time length to use the moving average value as the second detection value Vs 2 which is compared with the second detection value threshold Vth 2 .
- the second detection value threshold Vth 2 is stored in the central controller 800 m in advance.
- the second detection value threshold Vth 2 may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the second detection value threshold Vth 2 is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the second refrigerant. Also, in case of using a toxic refrigerant such as CO2 refrigerant, as the second refrigerant, it is preferable that the second detection value threshold Vth 2 is set to a value less than a value corresponding to the toxicity limit. In case of CO2 refrigerant, the value of the toxicity limit is 0.1 kg/m 3 .
- the second detection value threshold Vth 2 may be the same as or different from the first detection value threshold Vth 1 .
- step S 3022 m If the second detection value Vs 2 is equal to or greater than the second detection value threshold Vth 2 (S 3022 m : No), the central controller 800 m proceeds to step S 3030 h . If the second detection value Vs 2 is less than the second detection value threshold Vth 2 ( 3022 m : Yes), the central controller 800 m proceeds to step S 3050 h.
- the second leakage detector 502 m is disposed outside any casings of the compressor unit 111 m and the valve unit 200 m .
- a refrigerant leakage from pipe portions outside the casing or casings covering the compressor unit 111 m and/or the valve unit 200 m such as the utilization-side liquid refrigerant pipes 151 m or utilization-side gas refrigerant pipes 152 m (in particular the connection parts of the pipes), can be detected.
- the utilization-side liquid refrigerant pipes 151 m or utilization-side gas refrigerant pipes 152 m in particular the connection parts of the pipes
- the positions of the first and second leakage detectors 501 m , 502 m are not limited to those explained above.
- the second leakage detector 502 m may be disposed in a casing of the valve unit 200 m.
- the safety system 700 m explained above is preferred for the cascade-type system where HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf is used as the first refrigerant, and C02 refrigerant (carbon oxide refrigerant) as the second refrigerant, for instance.
- HFC refrigerant such as R32 and R410A
- HFO refrigerant such as R-1234ze and R-1234yf
- C02 refrigerant carbon oxide refrigerant
- the air conditioning systems are of an air-cooling type in which the first refrigerant is subjected to heat exchange with outdoor air.
- the safety systems explained in the fifth and sixth embodiments can also be applied to any other types including a water-cooling type in which the first refrigerant is subjected to heat exchange with coolant water or brine.
- a seventh embodiment of the present invention an air conditioning system of a water-cooling type is explained.
- the air conditioning system according to the seventh embodiment is similar to the air conditioning system 100 according to the fifth embodiment.
- the configuration of the piping is different from that of the fifth embodiment. This difference is explained hereinafter, and the other configurations not referred to are the same as the fifth embodiment unless otherwise indicated.
- the same reference signs as the fifth embodiment are appended to elements which are substantially the same as those of the fifth embodiment, and the explanations thereof are omitted.
- FIG. 22 is a schematic configuration diagram of the air conditioning system according to the seventh embodiment.
- the piping of the air conditioning system 100 n according to the seventh embodiment is separated into a first circuit 105 n for heat medium and a second circuit 106 n for first refrigerant.
- the heat medium may be coolant water or brine.
- the air conditioning system 100 n has a HEX unit 101 n , a compressor unit 111 n , a valve unit 200 h , and utilization-side units 120 which correspond to the HEX unit 101 h , the compressor unit 111 h , the valve unit 200 h , and the utilization-side units 120 according to the fifth embodiment, respectively.
- the HEX unit 101 n includes an outdoor heat exchanger 102 n corresponding to the outdoor heat exchanger 102 h of the fifth embodiment, and the compressor unit 111 n includes a compressor 112 n corresponding to the compressor 112 h of the fifth embodiment. Yet, the compressor unit 111 n does not include the switching mechanism 113 h , but includes a heat medium-refrigerant heat exchanger 117 n .
- the HEX unit 101 n and the compressor unit 111 n are connected by a supply pipe 107 n and a return pipe 108 n (first connection pipes) such that the heat medium circulates therebetween.
- the HEX unit 101 n may be a closed type cooling tower which cools the heat medium flowing in the outdoor heat exchanger 102 n by supplying air while sprinkling water, but is not limited to this.
- the heat medium-refrigerant heat exchanger 117 n is configured to allow each of the heat medium and the first refrigerant to flow therein so as to exchange heat between the heat medium and the first refrigerant.
- the heat medium-refrigerant heat exchanger 117 n is connected to the outdoor heat exchanger 102 n via the supply pipe 107 n and the return pipe 108 n .
- the air conditioning system 100 n further has a pump 118 n disposed to the supply pipe 107 n or the return pipe 108 n , preferably as part of the compressor unit 111 n .
- the pump 118 n is configured to induce a flow of the heat medium.
- the outdoor heat exchanger 102 n , the pump 118 n , the heat medium-refrigerant heat exchanger 117 n , and the pipes connecting them form the first circuit 105 n which circulates the heat medium.
- the heat medium-refrigerant heat exchanger 117 n is also connected to the discharge port of the compressor 112 m and the liquid refrigerant pipe 131 extending to the heatsource-side liquid pipe portion 310 of the valve unit 200 h .
- the suction port of the compressor 112 m is connected to the gas refrigerant pipe 132 extending to the low-pressure gas pipe portion 320 .
- the compressor 112 m the heat medium-refrigerant heat exchanger 117 n , the indoor heat exchangers 122 m , and the pipes connecting them form the second circuit 106 n which circulates the first refrigerant.
- the HEX unit 101 n is installed in the first space 931 h
- the compressor unit 111 n and the valve unit 200 h are installed in the second space 932 h
- the utilization-side units 120 are installed in the target space 933 h .
- Any of the safety systems 700 h 700 i , 700 j , 700 k according to the first embodiment and its variations may be applied to the air conditioning system 100 n.
- the compressor unit 111 n further has the refrigerant heat exchanger 114 m and part of the refrigerant pipes 131 m , 132 m for the second refrigerant (and preferably the pump 116 m ), and include a refrigerant circuit for circulating the first refrigerant between the compressor 112 h and the refrigerant heat exchanger 114 m.
- FIG. 23 is a schematic configuration diagram of another variation of the safety system according to any one of the fifth to seventh embodiments.
- a safety system 700 p as a variation may have the same configuration as the first embodiment except that the ventilator 730 is replaced with a damper 440 . Both the dampers 440 disposed to the first and second airflow passages 935 h , 936 h are closed in normal times.
- the central controller 800 p corresponding to the central controller 800 h of the fifth embodiment and may have the same hardware configuration as the central controller 800 h .
- the central controller 800 p is configured to perform basically the same operation as the central controller 800 h . However, the central controller 800 p does not perform the operation of step S 3030 h , and instead, control both the dampers 440 to open in step 3040 h.
- the safety system 700 p has a passage control structure that is configured to, when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, switch a state of the first and second airflow passages 935 h , 936 h from a normal state (a first passage state) to an emergency state (a second passage state) in which air is allowed to pass through the passages 935 h , 936 h more easily than in the normal state.
- the safety system 700 p can also switch the state of the second space from a first state to a second state in which a ventilation of the second space 932 h is promoted more than in the first state when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold.
- the ventilation achieved would be weaker than when a forced ventilation is performed, it is possible to reduce the cost of the safety system since a ventilator can be omitted.
- any other mechanism which can switch the state of the first and/or second airflow passage 935 h , 936 h to the second state mentioned above may be used.
- a shutter, a window plate, or a door plate may be used.
- the switch from the first state to the second state must be controllable from the central controller 800 m by means of an electric motor or the like.
- the compressor unit and the valve unit may be integrated to a single unit.
- the safety systems as shown in FIGS. 14 , 18 , 20 , and 23 may be suitable.
- the air conditioning system may have the three-pipe configuration.
- the air conditioning system may include a plurality of the valve units as with the first to fourth embodiments, and, between the valve unit and the utilization-side units 120 , one or more of the other valve units may be disposed.
- the casings of all of them may be connected by the connection structure.
- the heatsource-side liquid pipe portion 310 and the gas pipe portion or portions 320 , 340 need not necessarily be branched towards two or more of the utilization-side units 120 but directed towards only one among the utilization-side units 120 . Yet, when the valve unit has at least a liquid refrigerant pipe portion, a gas refrigerant pipe portion, a liquid control valve disposed in the liquid refrigerant pipe portion, and a gas control valve disposed in the gas refrigerant pipe portion within the casing, the safety system can improve the safety regarding refrigerant leakage of the air conditioning system.
- the first space, the second space, and the target space need not necessarily belong to the same building.
- the HEX unit may be installed on a ground outside a building, and/or the first space and the second space may be formed in different buildings.
- the term “building” includes a house, a hut, a ship, or the like.
- the damper 440 may also be disposed to the first opening 420 to which the connecting duct 740 a is connected, as with the second embodiment as shown in FIG. 6 .
- the number of the air passage, the number of the HEX unit connected to each compressor unit, the number of the compressor unit connected to each HEX unit, the number of the utilization-side unit connected to each compressor unit, the number of the utilization-side unit belonging to each unit family, and the number of the each of the first space, the second space, and the target space are not limited to those explained above.
- the utilization-side units belonging to the same valve unit may be installed different target spaces.
Abstract
An air conditioning system includes a compressor unit including a compressor, a heat exchanger unit including an outdoor heat exchanger, an indoor unit, and a valve unit including a liquid control valve and a gas control valve. The heat exchanger unit is installed in a first space, while the compressor unit and the valve unit are installed in a second space. The system further includes a first leakage detector disposed in the second space, and a ventilation control structure that is configured to switch the state of the second space from a first state to a second state when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold, in the second state a ventilation of the second space being promoted more than in the first state.
Description
- The present invention relates to an air conditioning system and a method for constructing the air conditioning system.
- In an air conditioning system for a plurality of target spaces, each of a liquid refrigerant pipe and a gas refrigerant pipe of a heat pump circuit is branched into a plurality of sub piping systems. The branched sub pipes in the sub piping systems are often provided with valves to zone the sub piping systems.
- Meanwhile, each valve used in the heat pump system tends to become a leakage point of refrigerant, and thus needs to be regularly checked and repaired as necessary. Hence, for the convenience of monitoring and maintenance, it is common to design a piping of a heat pump system so as to arrange a plurality of valves in one place. For example,
EP 3 091 314 A1 proposes to integrate a plurality of valves of the refrigerant sub pipes within a single casing to form a valve unit. Thereby, it is possible to not only ease the burden of monitoring/maintenance but also prevent refrigerant leaked at any valve from spreading to the surrounding area. - However, a heatsource-side unit of the air conditioning system, which includes a compressor and an outdoor heat exchanger, also includes potential leakage points of refrigerant. Hence, the configuration proposed by the
EP 3 091 314 A1 is not sufficient to improve safety of an air conditioning system regarding refrigerant leakage. - The object of the present invention is to provide an air conditioning system and a method for constructing an air conditioning system that can further improve safety regarding refrigerant leakage.
- A first aspect of the present invention provides an air conditioning system comprising: a compressor unit that has a compressor configured to compress first refrigerant; a heat exchanger unit that has an outdoor heat exchanger configured to exchange heat between air and the first refrigerant or between air and heat medium, the heat medium being subjected to a heat exchange with the first refrigerant; at least one indoor unit that has an indoor heat exchanger configured to exchange heat between the first refrigerant and air in a target space to be air-conditioned or between second refrigerant and air in the target space, the second refrigerant being subjected to a heat exchange with the first refrigerant; and at least one valve unit that has at least one liquid refrigerant pipe portion and at least one gas refrigerant pipe portion configured to allow the first refrigerant or the second refrigerant to flow therein between the compressor unit and the indoor unit, at least one liquid control valve disposed in the liquid refrigerant pipe portion, and at least one gas control valve disposed in the gas refrigerant pipe portion, wherein: the heat exchanger unit is installed in a first space; the compressor unit and the valve unit are installed in a second space which is different from any of the target space and the first space; and the air conditioning system further comprises a first leakage detector that is disposed in the second space and configured to detect at least a concentration of the first refrigerant in air, and a ventilation control structure that is configured to switch the state of the second space from a first state to a second state when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold, in the second state a ventilation of the second space being promoted more than in the first state.
- Since the heat exchange unit and the compressor unit are separated into different spaces, it is possible to make their ventilation environments different from each other. The second space being different from any of the target space and the first space means that the state of air in the second space has no direct relationship with the state of air in any of the target space and the first space. The first space may be an outdoor space or a space through which outdoor air is allowed to pass. Thus, the outdoor heat exchanger in the first space can be freely supplied with drafts of outdoor air, while the ventilation state of the second space in which the compressor unit and the valve unit are disposed can be restricted. For instance, the second space can be substantially closed in normal times. Thereby, when a refrigerant leakage has occurred at any of the compressor unit and the valve unit, the second space can prevent or restrain the leaked refrigerant from spreading to the surrounding area. Moreover, concentration of the leaked refrigerant in the second space can be decreased by discharging the air from the second space to an external space of the second space. Furthermore, the second space can be substantially closed during a normal operation of the heat pump system, and a refrigerant leakage detection can be made based on concentration of refrigerant in this substantially closed space.
- Thus, it is possible to swiftly detect an occurrence of a refrigerant leakage in any of the compressor unit and the valve unit and promote the ventilation of the second space by the ventilation control structure at an early stage. Thereby, it is possible to prevent concentration of the leaked refrigerant in both the second space and the surrounding area of the second space from becoming high in a more secure manner. This allows the monitoring/maintenance person to safely monitor, maintain, or repair the compressor unit and/or the valve unit. Accordingly, it is possible to improve safety of the air conditioning system regarding refrigerant leakage. It should also be noted that the above effects regarding refrigerant leakage in the compressor unit or the valve unit can be achieved without affecting the ventilation environment of the outdoor heat exchanger.
- In addition, the ventilation control structure is used in common for the compressor unit and the valve unit. Hence, the safety of the air conditioning system can be improved while preventing an increase in the installation cost of the system. Accordingly, with the air conditioning system according to the first aspect, it is possible to improve safety regarding refrigerant leakage at low cost, even in a case where the compressor should be arranged inside a building.
- Here, the external space to which the air is discharged by the ventilation control structure is preferably not an outer space directly surrounding the second space or an indoor space where a human or animal could come or reside. The external space is preferably an outdoor space.
- According to a preferred embodiment of the air conditioning system mentioned above, the ventilation control structure includes a passage control structure that is configured to, when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, switch a state of at least one airflow passage between the second space and an outer space outside of the second space from a first passage state to a second passage state, in the second passage state air being allowed to pass through the passage more easily than in the first passage state.
- The airflow passage may be an opening formed in a building structure defining the second space therein, a duct penetrating the building structure, a window frame or door frame embedded to the building structure, or the like. The passage control structure may include a check air damper, a shutter, a window plate, a door plate, or the like. The passage control structure may be configured to close the passage to achieve the first passage state in normal times, and open the passage to achieve the second state. Thus, the passage control structure need not necessarily cause a forced ventilation of the second space, but may simply induce a natural ventilation of the second space. Since a device for causing a forced ventilation such as a ventilator is not necessarily required, it is possible to avoid an increase in installation cost of the air conditioning system. It is preferable that two or more airflow passages are formed in the building structure to effectively induce the natural ventilation.
- According to another preferred embodiment of the air conditioning system mentioned above, the ventilation control structure includes a discharge structure that is configured to operate to discharge air from the second space when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold.
- With this configuration, since a forced ventilation is caused, it is possible to discharge the air containing refrigerant from the second space in a more secure way.
- According to further another preferred embodiment of the air conditioning system mentioned above which has the discharge structure, the discharge structure includes a ventilator that is configured to draw air from the second space towards an external space which is different from any of the target space and the second space, a controller that is configured to control the ventilator to operate when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, and a check air damper that is configured to keep closed an airflow passage between the second space and an outer space outside of the second space, and open the airflow passage when the ventilator is in operation.
- With the above configuration, it is possible to effectively discharge the air from the second space when a refrigerant leakage has occurred in the second space. Here, the ventilator may be configured to blow air to push the air within the second space out, or suck air to draw the air in the second space out.
- According to further another preferred embodiment of any one of the air conditioning system mentioned above which has the ventilator, the controller, and the check air damper, the second space is defined by a building structure; and the ventilator and the check air damper are disposed to the building structure.
- With the above configuration, the second space can be obtained by utilizing a building structure of the building to which the air conditioning system is installed, and the ventilator and the check air damper can be arranged by utilizing openings formed in the building structure. The second space may be one of the rooms of the building, or two rooms of the building which are connected to each other to form a single continuous space. Hence, it is possible to easily achieve the ventilation control structure. It is preferable that the building structure is configured such that the second space is substantially isolated from the outer space thereof when the ventilator is not in operation and the check air damper is closed.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above which has the ventilator, the controller, and the check air damper, the air conditioning system further comprises: first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space; a connection structure connecting the internal spaces of the first and second casings; an intake duct connecting the outer space of the second space and the internal space of the first casing; and a discharge duct connecting the internal space of the second casing and the external space, wherein the first leakage detector is disposed in the first or second casing that accommodates the compressor, the check air damper is disposed to the intake duct, and the ventilator is disposed to the discharge duct.
- With the above configuration, it is possible to make smaller the space in which a refrigerant leakage is to be detected and from which air is to be discharged, even in a case where the compressor unit and the valve unit are distanced from each other. Thus, it is possible to swiftly detect a refrigerant leakage occurred in any of the compressor unit and the valve unit, and thus swiftly discharge air containing leaked refrigerant. Moreover, even in a case where it is difficult to achieve a substantial isolation of the second space, it is possible to perform the swift detection of refrigerant leakage and the swift discharge of air without a large-scale modification of the building structure. Furthermore, the capability of the ventilator can also be made smaller when the space to be ventilated is smaller. Hence, it is also possible to reduce the installation cost of the air conditioning system.
- The intake duct and/or the discharge duct shared duct may be extended to the outdoor space. The ventilator may be configured to further discharge air surrounding the first and second casings. The ventilator may be disposed outside the second space.
- Here, for each of the compressor unit and the valve unit, the casing and other elements of the unit may be manufactured together. Thereby, it becomes easier to design the unit so as to enhance their performances such as airtightness of its casing. It also becomes easier to optimize the dimension of the unit, and a position of a maintenance door of the casing. Hence, it is possible to improve not only safety but also maintainability and functionality of the air conditioning system. Alternatively, the casing may be a retrofitted casing which is to be assembled around elements of an existing compressor unit or valve unit.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above which has the ventilator, the controller, and the check air damper, the air conditioning system further comprises: first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space; a first intake duct connecting the outer space of the second space and the internal space of the first casing; a second intake duct connecting the outer space of the second space and the internal space of the second casing; a connection structure connecting the internal spaces of the first and second casings; a discharge duct connecting the connection structure and the external space, wherein the first leakage detector is disposed in the first or second casing that accommodates the compressor, the check air damper is disposed to each of the first and second intake ducts, and the ventilator is disposed to the discharge duct.
- With the above configuration, the internal spaces of the casings are connected to each other in parallel. In other words, each of the internal spaces communicates with the discharge structure without being interposed by any other casing. Hence, it is possible to reduce static pressure capacity required of the ventilator.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above which has the ventilator, the controller, and the check air damper, the air conditioning system further comprises: a casing accommodating the compressor unit and the valve unit as part of the second space; an intake duct connecting the outer space of the second space and the internal space of the casing; a discharge duct connecting the internal space of the casing and the external space, wherein the first leakage detector is disposed in the casing, the check air damper is disposed to the intake duct, and the ventilator is disposed to the discharge duct.
- With the above configuration, it is possible to make smaller the space in which a refrigerant leakage is to be detected and from which air is to be discharged. Thus, it is possible to swiftly detect a refrigerant leakage occurred in any of the compressor unit and the valve unit, and swiftly discharge air containing leaked refrigerant. Moreover, even in a case where it is difficult to achieve a substantial isolation of the second space, it is possible to perform the swift detection of refrigerant leakage and the swift discharge of air without a large-scale modification of the building structure. Furthermore, compared with the configuration in which two casings are arranged, the cost for forming the space to be ventilated can be reduced. The capability of the ventilator can also be made smaller when the space to be ventilated is smaller. Hence, it is also possible to reduce the installation cost of the air conditioning system.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above which has the ventilator, the controller, and the check air damper, the indoor heat exchanger is configured to exchange heat between the second refrigerant and air in the target space; the liquid refrigerant pipe portion and the gas refrigerant pipe portion of the valve unit are configured to allow the second refrigerant to flow therein; the air conditioning system further comprises a second leakage detector that is disposed in the second space and configured to detect at least a concentration of the second refrigerant in air; and the controller is further configured to control the ventilator to start operating when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold.
- With the above configuration, in any case of when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold, and when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold, the controller is configured to control the ventilator to start operating. Thus, even in a case where the air conditioning system is of a cascade-type which uses different types of refrigerants in the compressor unit and the valve unit, it is possible to improve the safety regarding leakage of any of the refrigerants.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above which has the first and second casings and the second leakage detector, the compressor unit further has a refrigerant heat exchanger configured to exchange heat between the first refrigerant and the second refrigerant; the first leakage detector is disposed in the first casing; and the second leakage detector is disposed in the second casing or a space which is part of the second space and not part of the internal spaces of the first and second casings.
- With the above configuration, it is possible to detect a leakage of the second refrigerant from piping outside of the casings. Thus, the safety of the air conditioning system can be further improved.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above, the air conditioning system further comprise: first connection pipes connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween; and second connection pipes connecting the compressor unit, the valve unit, and the indoor unit such that the first refrigerant or the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit.
- With the above configuration, a heat pump circuit is formed between the outdoor heat exchanger and the indoor heat exchanger.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above, the air conditioning system comprises a plurality of the indoor units; and the valve unit further has at least one liquid refrigerant branch pipe branching the liquid refrigerant pipe portion towards the indoor units and at least one gas refrigerant branch pipe branching the gas refrigerant pipe portion towards the indoor units.
- The branching points of the refrigerant pipes are also potential refrigerant leakage points. Hence, since such potential leakage points are also accommodated in the second space, the safety of the air conditioning system regarding refrigerant leakage can be further improved.
- According to further another preferred embodiment of any one of the air conditioning systems mentioned above, the second space is a space which is any one of a machine room, a computer room, and a warehouse in a building.
- With the above configuration, the second space is a space where a human is unlikely to reside in normal times. Thus, the safety of the air conditioning system regarding refrigerant leakage can be further improved.
- A second aspect of the present invention provides a method for constructing any one of the air conditioning systems mentioned above, comprising: installing the compressor unit and the valve unit in the second space which is defined by a building structure of a building; disposing the first leakage detector in the second space; installing the heat exchanger unit in the first space; installing the indoor unit in a space which is within the building and different from the first space and the second space; connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween; connecting the compressor unit, the valve unit, and the indoor unit such that the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit; and installing the ventilation control structure to the building.
- By the above method, it is possible to obtain any one of the air conditioning systems mentioned above, and the building installed with the air conditioning system.
- According to a preferred embodiment of the method for constructing the air conditioning system mentioned above, the building structure includes a floor, a ceiling facing the floor, at least one wall which connects the floor and the ceiling and surrounds a space between the floor and a ceiling, and a door arranged in the floor, the ceiling, or the wall.
- With the above configuration, a room of the building can be used as the second space. Thus, it is possible to improve safety regarding refrigerant leakage of the air conditioning system at low cost.
- A reference example of a safety system comprises: a plurality of valve units used for a heat pump system, each of the valve units having at least one liquid refrigerant pipe portion, at least one gas refrigerant pipe portion, at least one liquid control valve disposed in the liquid refrigerant pipe portion, at least one gas control valve disposed in the gas refrigerant pipe portion, a casing accommodating at least the liquid control valve and the gas control valve and formed with at least two openings, and a refrigerant leakage detector configured to detect an occurrence of a refrigerant leakage in an internal space of the casing; a connection structure connecting the internal spaces of the casings via the openings; and a discharge structure connected to the connection structure or one of the casings, and configured to discharge air from the internal space of the casing in which a refrigerant leakage has occurred.
- If separated casings are arranged for a plurality of valve units, it is burdensome and takes time to open each of the casings to check whether a refrigerant leakage has occurred in any casing. Furthermore, if a refrigerant leakage has occurred in any casing, the internal space of the casing would have already been permeated with a significant amount of leaked refrigerant when the monitoring/maintenance person arrives to open the casing. For instance, some refrigerants used are flammable or slightly flammable. Thus, opening such a casing is undesirable from safety perspective. In this regard, with the above configuration, even if a refrigerant leakage has occurred at a valve in any one of the valve units, the casing accommodating the valve can prevent or restrain the leaked refrigerant from spreading to the surrounding area. Moreover, concentration of the leaked refrigerant in the internal space of the casing can be decreased by discharging the air from the internal space to an external space of the casings. Furthermore, each casing can be substantially closed during a normal operation of the heat pump system, and a refrigerant leakage detection can be made based on concentration of refrigerant in this substantially closed space.
- Thus, it is possible to swiftly detect an occurrence of a refrigerant leakage in the valve unit and start operation of the discharge structure at an early stage. Thereby, it is possible to prevent concentration of the leaked refrigerant in both the casing in which the refrigerant leakage has occurred and the surrounding area of the casing from becoming high in a more secure manner. This allows the monitoring/maintenance person to safely monitor, maintain, or repair the valves. Accordingly, it is possible to improve safety of the heat pump system regarding refrigerant leakage.
- In addition, the discharge structure is used in common for the plurality of valve units. Hence, the safety of the heat pump system can be improved while preventing an increase in the installation cost of the system even in a case where the valves are arranged in separate locations.
- Here, the external space to which the air is discharged by the discharge structure is preferably not an outer space directly surrounding any casing or an indoor space where a human or animal could come or reside. The external space is preferably an outdoor space. The heat pump system to which a plurality of the valve units belong may include a plurality of separate heat pump circuits. In other words, the pipings of the valve units need not necessary be connected to each other. In each of the valve units, the pipe portions, the valves, and the casing may be manufactured together. Thereby, it becomes easier to design the valve unit so as to enhance its performance such as airtightness of the casing. It also becomes easier to optimize the dimension of the valve unit, and a position of a maintenance door of the casing. Hence, it is possible to improve not only safety but also maintainability and functionality of the valve unit. Alternatively, the casing may be a retrofitted casing which is to be assembled around existing valves.
- According to a preferred modification of the safety system mentioned above, the discharge structure includes a shared duct connected to the connection structure or one of the casings, and a ventilator disposed to the shared duct.
- With the above configuration, it is possible to effectively discharge the air from the internal space of the casing when a refrigerant leakage in the casing has occurred. Here, the ventilator may be configured to blow air to push the air within the casing out, or suck air to draw the air in the casing out. The shared duct may be extended to the outdoor space, and the ventilator may be disposed in or attached to the shared duct. The ventilator may be configured to further discharge air surrounding at least one of the casings, e.g. air in a ceiling or a pipe shaft.
- According to another preferred modification of the safety system mentioned above with the shared duct and the ventilator, the shared duct has a first end and a second end; the ventilator is disposed to the shared duct at or close to the second end, and configured to draw air in the shared duct towards the second end; and the shared duct is connected to the connection structure or one of the casings on a side of the first end with respect to the ventilator.
- With the above configuration, the internal spaces of the casings, the connection structure, and the most part of the shared duct are kept in under pressure when the air is discharged. Thus, it is possible to prevent the air containing refrigerant from leaking to the surrounding area.
- According to further another preferred modification of the safety system mentioned above with the second end of the shared duct, the second end of the shared duct is open to an outdoor space.
- With the above configuration, the air containing refrigerant can be discharged to the outdoor space. Thus, the safety of the heat pump system can be further improved.
- According to further another preferred modification of any one of the safety systems mentioned above with the shared duct and the ventilator, the safety system further includes: a controller configured to control the ventilator to start operating when a refrigerant leakage in any one of the valve units has occurred.
- With the above configuration, it is possible to discharge the air containing refrigerant in a more secure manner when the refrigerant leakage has occurred.
- According to further another preferred modification of any one of the safety systems mentioned above with a controller, each of the refrigerant leakage detectors are configured to output detection result information; and the controller is configured to receive the detection result information outputted from any one of the refrigerant leakage detectors, and identify in which of the valve units a refrigerant leakage has occurred based on the received detection result information.
- With the above configuration, it is possible to identify the valve unit in which a refrigerant leakage has occurred, and perform a control of the ventilator based on the determination result. Here, the detection result information indicates whether or not a refrigerant leakage in the corresponding valve unit has occurred, and may indicate an identification of the valve unit in which the refrigerant leakage has occurred (hereinafter referred to as “the valve unit of refrigerant leakage”).
- According to further another preferred modification of any one of the safety systems mentioned above with the shared duct and the ventilator, the at least two openings of each of the casings include a first opening and a second opening: and the connection structure includes a plurality of individual ducts connected to the second openings of the casings, respectively, and further connected to the shared duct in common.
- With the above configuration, the internal spaces of the casings are connected to each other in parallel. In other words, each of the internal spaces communicates with the discharge structure without being interposed by any other casing. Hence, it is possible to reduce static pressure capacity required of the ventilator.
- According to further another preferred modification of any one of the safety systems mentioned above with the individual ducts, each of the valve units further has a damper configured to block air to pass through the first opening when the damper is closed, and allow air to pass through the first opening when the damper is open; and the controller is configured to control the dampers such that, when the ventilator operates due to the occurrence of the refrigerant leakage, the damper of the valve unit in which the refrigerant leakage has occurred is open while the damper of the valve unit in which no refrigerant leakage has occurred is closed.
- It is preferable that all the dampers are closed during a normal operation of the heat pump system to swiftly detect a refrigerant leakage and prevent the leaked refrigerant from spreading out towards the surrounding area. Meanwhile, if the damper is closed, the first opening cannot work as an intake port of an external air or an exhaust port of the internal air, and it is difficult to replace air in the internal space of the casing even if the ventilator operates. In this regard, the above configuration opens the damper of the valve unit of refrigerant leakage to effectively discharge air while achieving a swift detection of a refrigerant leakage. Moreover, the other damper or dampers are kept closed, and thereby the valve unit subject to the air discharge can be limited to the valve unit of refrigerant leakage. In general, it is rare that refrigerant leakages occur in different valve units at a time. Hence, it is possible to reduce air volume capacity required of the ventilator. Each of the dampers may be directly attached to the first opening or arranged away from the first opening and connected to the first opening via a duct.
- According to further another preferred modification of any one of the safety systems mentioned above with the individual ducts and the dampers, the controller includes a plurality of unit controllers disposed in the valve units, respectively, and a central controller configured to communicate with the unit controllers; each of the refrigerant leakage detectors is configured to transmit detection result information to the central controller via the corresponding unit controller; and the central controller is configured to determine whether a refrigerant leakage in any one of the valve units has occurred based on the detection result information received from the valve unit, and, when the refrigerant leakage has occurred in any one of the valve units, transmit a damper open command to the damper of the valve unit in which the refrigerant leakage has occurred via the corresponding unit controller and control the ventilator to start operating.
- With the above configuration, it is possible to identify the valve unit of refrigerant leakage, and perform a centralized control of the ventilator and the dampers based on the determination result in a more secure manner. Here, the detection result information indicates whether or not a refrigerant leakage in the valve unit has occurred, and may indicate an identification of the valve unit of refrigerant leakage. The damper open command instructs the damper to open, and may designate an identification of the valve unit of which the damper should open.
- According to further another preferred modification of any one of the safety systems with the shared duct and the ventilator, the at least two openings of each of the casings include a first opening and a second opening; the connection structure includes at least one connecting duct connected on one side to the second opening of one of the casings and connected on another side to the first opening of another one of the casings; and the shared duct of the discharge structure is connected to the second opening of one of the casings to which there is no connecting duct connected.
- With the above configuration, the internal spaces of the casings are connected to the discharge structure in series. In other words, at least one of the internal spaces communicates with the discharge structure via one or more of the other casings. Thereby, it is possible to reduce the total length of ducts for connecting the casings to the discharge structure, and thus reduce the installation cost of the system. The shared duct and the ventilator may be integrated as a single element. If one of the casings has a part exposed to the outdoor space, such a single element may be disposed in this part.
- According to further another preferred modification of any one of the safety systems mentioned above with the connecting duct, each of the valve units further has a damper configured to block air to pass through the first opening when the damper is closed, and allow air to pass through the first opening when the damper is open; and the controller is configured to control the dampers of all the valve units to be open when the ventilator operates due to the occurrence of the refrigerant leakage.
- It is preferable that all the dampers are closed during a normal operation of the heat pump system to swiftly detect a refrigerant leakage and prevent the leaked refrigerant from spreading out towards the surrounding area. Meanwhile, if the damper of any one of the casings is closed, the first openings of the casings continuing in series cannot work as an intake port of an external air or an exhaust port of the internal air, and it is difficult to replace air in their internal space even if the ventilator operates. In this regard, the above configuration opens the dampers of all the valve units continuing in series to effectively discharge air while achieving a swift detection of a refrigerant leakage. Each of the dampers may be directly attached to the first opening or arranged away from the first opening and connected to the first opening via a duct.
- According to further another preferred modification of any one of the safety systems mentioned above with the connecting duct and the dampers, the controller includes a plurality of unit controllers disposed in the valve units, respectively, and a central controller configured to communicate with the unit controllers; each of the refrigerant leakage detectors is configured to transmit detection result information to the central controller via the corresponding unit controller; and the central controller is configured to determine whether a refrigerant leakage in any one of the valve units has occurred based on the detection result information received from the valve unit, and, when the refrigerant leakage has occurred, transmit a damper open command to the dampers of all the valve units via the unit controllers and control the ventilator to start operating.
- With the above configuration, it is possible to detect an occurrence of refrigerant leakage in any valve unit to perform a centralized control of the ventilator and the dampers in a more secure manner. Here, the detection result information indicates whether or not a refrigerant leakage in the valve unit has occurred, and may indicate an identification of the valve unit of refrigerant leakage. The damper open command instructs the damper to open, and may designate an identification of the valve unit of which the damper should open.
- A reference example of a method for assembling any one of the safety systems mentioned above, wherein the casing is formed from a plurality of casing parts, comprises: arranging, for each of the valve units, the corresponding casing parts around at least the liquid control valve and the gas control valve of the valve unit; fixing, for each of the valve units, the corresponding casing parts to each other; disposing, for each of the valve units, the refrigerant leakage detector, arranging the connection structure so as to connect the internal spaces of the casings; and connecting the discharge structure to the connection structure or one of the casings.
- By the above method, it is possible to obtain the safety system mentioned above even with an existing heat pump system.
- A reference example of an air conditioning system comprises: any one of the safety systems mentioned above, a heatsource-side unit including a compressor and a heatsource-side heat exchanger; a plurality of utilization-side units each including a utilization-side heat exchanger; a liquid refrigerant piping extending between the heatsource-side unit and the utilization-side units, and including the liquid refrigerant pipe portions; a gas refrigerant piping extending between the heatsource-side unit and the utilization-side units, and including the gas refrigerant pipe portions; and an expansion mechanism disposed in the liquid refrigerant piping.
- With the above configuration, it is possible to obtain air conditioning system with high safety regarding refrigerant leakage at valves.
- According to a preferred modification of the air conditioning system mentioned above which includes the controller, the air conditioning system further comprises: a system controller configured to control an air conditioning operation of the air conditioning system, wherein at least part of the controller of the safety system is a part of the system controller.
- With the above configuration, it is possible to integrate at least a part of the controller for air conditioning and at least a part of the system controller for the operation of the safety system. Thereby, the total installation cost can be reduced. The integrated part of the system controller may be separated away from the other part of the system controller.
- According to another preferred modification of any one of the air conditioning systems mentioned above which includes the ventilator, the air conditioning system further comprises: a plurality of sections each including the plurality of valve units, the connection structure, and the discharge structure, wherein the controller is configured to control the ventilator of only the section in which a refrigerant leakage has occurred to start operating.
- With the above configuration, it is possible to integrate the controllers for a plurality of the safety systems each having the connection structure and the discharge structure. Thereby, the total installation cost can be reduced.
-
FIG. 1 is a schematic configuration diagram of an air conditioning system with valve units according to a first embodiment of the present invention. -
FIG. 2 is a schematic configuration diagram of a valve unit shown inFIG. 1 . -
FIG. 3 is a schematic configuration diagram of a safety system according to the first embodiment. -
FIG. 4 is a flow chart indicating an operation performed by a unit controller shown inFIG. 3 . -
FIG. 5 is a flow chart indicating an operation performed by a central controller shown inFIG. 3 . -
FIG. 6 is a schematic configuration diagram of the safety system according to a second embodiment of the present invention. -
FIG. 7 is a flow chart indicating an operation performed by a central controller shown inFIG. 6 . -
FIG. 8 is a schematic configuration diagram of the safety system according to a third embodiment of the present invention. -
FIG. 9 is a grouping table used by a central controller shown inFIG. 9 . -
FIG. 10 is a schematic configuration diagram of the safety system according to a fourth embodiment of the present invention. -
FIG. 11 is a grouping table used by the central controller according to a fourth embodiment of the present invention. -
FIG. 12 is a schematic configuration diagram of a valve unit according to a modification of the present embodiment. -
FIG. 13 is a schematic configuration diagram of an air conditioning system according to a fifth embodiment of the present invention. -
FIG. 14 is a schematic configuration diagram of a safety system of the air conditioning system shown inFIG. 13 . -
FIG. 15 is a flow chart indicating an operation performed by a central controller shown inFIG. 14 . -
FIG. 16 is a schematic configuration diagram of a safety system according to a first variation of the fifth embodiment. -
FIG. 17 is a schematic configuration diagram of a safety system according to a second variation of the fifth embodiment. -
FIG. 18 is a schematic configuration diagram of a safety system according to a third variation of the fifth embodiment. -
FIG. 19 is a schematic configuration diagram of an air conditioning system according to a sixth embodiment of the present invention. -
FIG. 20 is a schematic configuration diagram of an example of a safety system of the air conditioning system shown inFIG. 19 . -
FIG. 21 is a flow chart indicating an operation performed by a central controller shown inFIG. 20 . -
FIG. 22 is a schematic configuration diagram of an air conditioning system according to a seventh embodiment of the present invention. -
FIG. 23 is a schematic configuration diagram of a variation of the safety system according to any one of the fifth to seventh embodiments. - Preferred embodiments of an air conditioning system and a safety system according to the present invention will be described with reference to the drawings.
- (Configuration of Air Conditioning System)
- The air conditioning systems according to a first embodiment of the present embodiment is a multi air conditioning system with a so-called three-pipe configuration, which includes a heatsource-side unit and a plurality of utilization-side units.
-
FIG. 1 is a schematic configuration diagram of the air conditioning system according to the first embodiment. - As shown in
FIG. 1 , theair conditioning system 100 comprises a heatsource-side unit 110, and a plurality of utilization-side units 120 connected to the heatsource-side unit 110 via refrigerant pipes. The utilization-side units 120 are divided into a plurality ofunit families 121, e.g. first to third unit families 121_1, 121_2, 121_3. Yet, the number of theunit families 121 is not limited to three, and may be two, four, or more. The number of the utilization-side unit 120 belonging to each of theunit families 121 is also not limited. - The heatsource-
side unit 110 includes a compressor, and a condenser and an evaporator (heatsource-side heat exchangers) (not shown). The heatsource-side unit 110 also extends out a liquidrefrigerant pipe 131, a low-pressuregas refrigerant pipe 132, and a high-pressuregas refrigerant pipe 133. The liquidrefrigerant pipe 131 communicates with each of the condenser and the evaporator. The low-pressuregas refrigerant pipe 132 communicates with a suction port of the compressor. The high-pressuregas refrigerant pipe 133 communicates with a discharge port of the compressor. - The liquid
refrigerant pipe 131 branches into a plurality of heatsource-side liquid pipes 141 towards the first to third unit families 121_1, 121_2, 121_3. The low-pressuregas refrigerant pipe 132 branches into a plurality of heatsource-side low-pressure gas pipes 142 towards the first to third unit families 121_1, 121_2, 121_3. The high-pressuregas refrigerant pipe 133 branches into a plurality of heatsource-side high-pressure gas pipes 143 towards the first to third unit families 1211, 1212, 121_3. - For each of the
unit families 121, the heatsource-side liquid pipe 141 branches into a plurality of utilization-side liquidrefrigerant pipes 151 towards the utilization-side units 120 which belong to theunit family 121. For each of theunit families 121, the heatsource-side low-pressure gas pipe 142 branches into a plurality of utilization-sidegas refrigerant pipes 152 towards the utilization-side units 120 which belong to theunit family 121. For each of theunit families 121, the heatsource-side high-pressure gas pipe 143 branches towards the utilization-side units 120 which belong to theunit family 121, and each of the branched pipes merges with the corresponding utilization-sidegas refrigerant pipe 152. - Each of the utilization-
side units 120 includes a utilization-side heat exchanger (not shown). For each of the utilization-side units 120, the utilization-side heat exchanger communicates with the corresponding utilization-side liquidrefrigerant pipe 151 and utilization-sidegas refrigerant pipe 152. - In other words, in the
air conditioning system 100, a liquid refrigerant piping and a gas refrigerant piping extends between the heatsource-side unit 110 and the utilization-side units 120, while branching towards theunit families 121 and then towards the utilization-side units 120 in each of theunit families 121, to form a heat pump circuit. Thereby, it is possible to supply hot/cold heat from the heatsource-side unit 110 to each of the utilization-side units 120 by circulating refrigerant. - The
air conditioning system 100 further includes first to third valve units 200_1, 200_2, 200_3 for the first to third unit families 121_1, 121_2, 120_3, respectively. For each of theunit families 121, the branching points towards the corresponding utilization-side units 120 are disposed in thecorresponding valve unit 200. The first to third valve units 200_1, 200_2, 200_3 have a substantially same configuration. Thus, in the following descriptions, the term “thevalve unit 200” means any one of the first to third valve units 200_1, 200_2, 200_3. The details of thevalve unit 200 are explained hereinafter. - The
air conditioning system 100 includes a safety system for improving safety of the air conditioning system 100 (a heat pump system) regarding refrigerant leakage. The first to third valve units 200_1, 200_2, 200_3 are part of the safety system. The details of the safety system will be explained later. - (Configuration of Valve Unit)
-
FIG. 2 is a schematic configuration diagram of thevalve unit 200. - As shown in
FIG. 2 , thevalve unit 200 comprises amulti branch selector 300, acasing 400, adamper 440, arefrigerant leakage detector 500, and aunit controller 600. Thecasing 400 accommodates themulti branch selector 300 therein. Therefrigerant leakage detector 500 and theunit controller 600 are disposed in aninternal space 401 of thecasing 400. Yet, theunit controller 600 may be disposed on or outside thecasing 400. - The
multi branch selector 300 includes a heatsource-sideliquid pipe portion 310, a plurality of utilization-sideliquid pipe portions 311, a low-pressuregas pipe portion 320, a plurality of low-pressuregas sub pipes 321, a plurality of utilization-sidegas pipe portions 330, a high-pressuregas pipe portion 340, a plurality of high-pressuregas sub pipes 341, a plurality ofbypass pipes 351, and a plurality ofrefrigerant heat exchangers 352. Themulti branch selector 300 further includes a plurality of low-pressuregas control valves 361, a plurality of high-pressuregas control valves 362, a plurality ofexpansion mechanisms 363, a plurality of liquid shut-offvalves 364, and a plurality of gas shut-offvalves 365. - The numbers of the utilization-side
liquid pipe portions 311, the low-pressuregas sub pipes 321, the utilization-sidegas pipe portions 330, the high-pressuregas sub pipes 341, thebypass pipes 351, therefrigerant heat exchangers 352, the low-pressuregas control valves 361, the high-pressuregas control valves 362, theexpansion mechanisms 363, the liquid shut-offvalves 364, and the gas shut-offvalves 365 may be the same as the number of the utilization-side units 120 which belong to the corresponding unit family 121 (seeFIG. 1 ). - The heatsource-side
liquid pipe portion 310, the low-pressuregas pipe portion 320, the high-pressuregas pipe portion 340 are parts of the corresponding heatsource-side liquid pipe 141, heatsource-side low-pressure gas pipe 142, and heatsource-side high-pressure gas pipe 143 (seeFIG. 1 ). The utilization-sideliquid pipe portions 311 are parts of the corresponding utilization-side liquid refrigerant pipes 151 (seeFIG. 1 ). The low-pressuregas sub pipes 321, the high-pressuregas sub pipes 341, and the utilization-sidegas pipe portions 330 are parts of the corresponding utilization-side gas refrigerant pipes 152 (seeFIG. 1 ). One of the utilization-sideliquid pipe portions 311 and one of the utilization-sidegas pipe portions 330 communicate with the same utilization-side heat exchanger of one of the utilization-side units 120. - In the
multi branch selector 300, the heatsource-sideliquid pipe portion 310 branches into the utilization-sideliquid pipe portions 311, the low-pressuregas pipe portion 320 branches into the low-pressuregas sub pipes 321, and the high-pressuregas pipe portion 340 branches into the high-pressuregas sub pipes 341. One of the low-pressuregas sub pipes 321 and one of the high-pressuregas sub pipes 341 are connected to one of the utilization-sidegas pipe portions 330. It can also be said that each of the low-pressuregas pipe portion 320 branches into the utilization-sidegas pipe portions 330 via the low-pressuregas sub pipes 321, and that the high-pressuregas pipe portion 340 branches into the utilization-sidegas pipe portions 330 via the high-pressuregas sub pipes 341. It can also be said that each of the utilization-sidegas pipe portions 330 branches into the low-pressuregas pipe portion 320 and the high-pressuregas pipe portion 340 via one of the low-pressuregas sub pipes 321 and one of the high-pressuregas sub pipes 341. - The
bypass pipes 351 are connected to the utilization-sideliquid pipe portions 311, respectively, and each connected to the low-pressuregas pipe portion 320. In other words, one of thebypass pipes 351 branches from one of the utilization-sideliquid pipe portions 311 and merges with the low-pressuregas pipe portion 320. - The
expansion mechanisms 363 are disposed in thebypass pipes 351, respectively. Each of theexpansion mechanisms 363 is configured to decompress and expand refrigerant flowing from the corresponding utilization-sideliquid pipe portion 311 in thebypass pipe 351. Each of theexpansion mechanisms 363 may be an electric expansion valve. - The
refrigerant heat exchangers 352 are provided to thebypass pipes 351, respectively. Each of therefrigerant heat exchangers 352 is configured to cause a heat-exchange between refrigerant flowing in one of the utilization-sideliquid pipe portions 311 and refrigerant flowing in thecorresponding bypass pipe 351 that has been decompressed and expanded by thecorresponding expansion mechanism 363. In other words, each of therefrigerant heat exchangers 352 forms a subcooling system in combination with the corresponding utilization-sideliquid pipe portion 311,bypass pipe 351, andexpansion mechanism 363. Each of therefrigerant heat exchangers 352 may have two flow channels which form a part of the utilization-sideliquid pipe portion 311 and a part of thebypass pipe 351, respectively, and have thermal conductance therebetween. - The low-pressure
gas control valves 361 are disposed in the low-pressuregas sub pipes 321, respectively. Each of the low-pressuregas control valves 361 is configured to switch between an open state and a closed state, i.e. whether or not to allow refrigerant to flow between the low-pressuregas pipe portion 320 and the corresponding utilization-sidegas pipe portion 330. The state of each of the low-pressuregas control valves 361 is controlled by theunit controller 600 in accordance with an operation mode desired for the corresponding utilization-side unit 120. Each of the low-pressuregas control valves 361 may be an electric valve. - The high-pressure
gas control valves 362 are disposed in the high-pressuregas sub pipes 341, respectively. Each of the high-pressuregas control valves 362 is configured to switch between an open state and a closed state, i.e. whether or not to allow refrigerant to flow between the high-pressuregas pipe portion 340 and the corresponding utilization-sidegas pipe portion 330. The state of each of the high-pressuregas control valves 362 is controlled by theunit controller 600 in accordance with an operation mode desired for the corresponding utilization-side unit 120. Each of the high-pressuregas control valves 362 may be an electric valve, and preferably formed with a minute channel. - The liquid shut-off
valves 364 are disposed in the utilization-sideliquid pipe portions 311, respectively. The gas shut-offvalves 365 are disposed in the utilization-sidegas pipe portions 330, respectively. The liquid shut-offvalve 364 and the gas shut-offvalve 365 disposed in the utilization-sideliquid pipe portion 311 and the utilization-sidegas pipe portion 330 which communicate with the same utilization-side heat exchanger define a utilization-side piping section which extends therebetween and includes at least the utilization-side heat exchanger. Each of the liquid shut-offvalves 364 and the gas shut-offvalves 365 may be an electric valve. - The
casing 400 may have a substantially box shape, and is large enough to accommodate at least themulti branch selector 300 and therefrigerant leakage detector 500 therein. Thecasing 400 may be made of metal plates, carbon fibre plates, fire-retardant resin plates, or the like. Thecasing 400 is formed with a plurality ofpipe apertures 410. - The plurality of
pipe apertures 410 are configured to allow the pipes extending from the multi branch selector 300 (hereinafter referred to as “the extending pipes”) to pass therethrough, respectively. In other words, the plurality ofpipe apertures 410 are formed at positions corresponding to the positions of the extending pipes, and each have diameter greater than the diameter of the corresponding extending pipe. Here, such extending pipes include the heatsource-sideliquid pipe portion 310, the low-pressuregas pipe portion 320, the high-pressuregas pipe portion 340, the utilization-sideliquid pipe portions 311, and the utilization-sidegas pipe portions 330. - Each of the extending pipes may have a
pipe connection part 370 for being connected to the corresponding outer pipes, i.e. the other part of the corresponding heatsource-side liquid pipe 141, heatsource-side low-pressure gas pipe 142, heatsource-side high-pressure gas pipe 143, utilization-side liquidrefrigerant pipe 151, or utilization-side gas refrigerant pipe 152 (seeFIG. 1 ). It is preferable that thepipe connection parts 370 are arranged outside of thecasing 400. - The
casing 400 is further formed with afirst opening 420, and asecond opening 430. It is preferable that thefirst opening 420 and thesecond opening 430 are arranged on opposite sides of thecasing 400 with respect to the center part of theinternal space 401. - Especially when refrigerant heavier than atmospheric air such as R32 refrigerant is used, it is preferable that both the
first opening 420 and thesecond opening 430 are arranged closer to the top part of thecasing 400. Thereby, it is possible to prevent leaked refrigerant from spreading out to the surrounding area of thecasing 400 in a more secure manner, and thereby swiftly detect an occurrence of a refrigerant leakage in thecasing 400. Yet, it might also be an option to arrange thefirst opening 420 closer to the bottom part of thecasing 400 while arranging thesecond opening 430 closer to the top part of thecasing 400 such that refrigerant accumulated at the bottom can be effectively discharged. In any cases, the arrangement of thefirst opening 420 and thesecond opening 430 is not limited to the above. - The
damper 440 is directly attached to thefirst opening 420. Alternatively, thedamper 440 may be arranged away from thefirst opening 420 inside or outside thecasing 400, and connected to thefirst opening 420 via a duct. Thedamper 440 is configured to block air to pass through thefirst opening 420 when thedamper 440 is closed and allow air to pass through thefirst opening 420 when thedamper 440 is open. More specifically, thedamper 440 includes aflap 441, and an electric motor (not shown) for moving the flap to switch between a closed position in which the flap closes off thefirst opening 420 and an open position in which the flap does not close off thefirst opening 420. The motor is controlled by theunit controller 600 as explained later. As shown inFIG. 2 . thedamper 440 may be a normally closed damper which is closed during a normal operation of theair conditioning system 100, i.e. when no refrigerant leakage has occurred. - The
second opening 430 is configured to allow air to pass therethrough between theinternal space 401 and an external space outside thecasing 400. As explained later, a duct is connected tosecond opening 430 on the outside of thecasing 400. Thesecond opening 430 may be provided with a damper which is controlled to move synchronously with thedamper 440 of thefirst opening 420. - It is also preferable that the
casing 400 has a maintenance door configured to allow a monitoring/maintenance person to check the states of themulti branch selector 300, therefrigerant leakage detector 500, and theunit controller 600, and/or repair them through the opened door, as necessary. -
Insulators 450 are applied to thecasing 400 such that theinternal space 401 of thecasing 400 is substantially isolated from the external space outside thecasing 400 at the parts other than thefirst opening 420 and thesecond opening 430. Theinsulators 450 may include tubular insulators fitted into the gaps between outer surfaces of the extending pipes of themulti branch selector 300 and inner edges of thepipe apertures 410, respectively. Eachinsulator 450 may be a foam tube, a foam wrap, a foam filler, a caulk, a tape, or the like. The foam tube with a cut line extending in its axis direction is easy to fit into the gap. The thickness of the foam tube is preferably equal to or slightly greater than the clearance between the outer surface of the corresponding extending pipe and the inner surface of thecorresponding pipe aperture 410. Theinsulators 450 may be attached to the extending pipes before assembling thecasing 400. - The
insulators 450 may also be applied to other gaps in thecasing 400, such as the gap between theflap 441 in the closed position and a housing of thedamper 440, the gap between the housing of thedamper 440 and edges offirst opening 420, and the gap between the maintenance door and a door frame of thecasing 400. - The
refrigerant leakage detector 500 is configured to detect an occurrence of a refrigerant leakage in theinternal space 401 of thecorresponding casing 400. Therefrigerant leakage detector 500 is configured to detect a concentration of the refrigerant in an air surrounding therefrigerant leakage detector 500, and continuously or regularly output a detector signal indicating a detection value Vs which corresponds to the detected concentration to theunit controller 600. Therefrigerant leakage detector 500 may be a semi-conductor gas sensor reactive to the refrigerant used in theair conditioning system 100. In a case where refrigerant which is heavier than atmospheric air, such as R32 refrigerant, therefrigerant leakage detector 500 is preferably disposed in theinternal space 401 at or close to an inner bottom surface of thecasing 400. - As mentioned later, it is determined by the
unit controller 600 whether a refrigerant leakage in the corresponding casing 400 (hereinafter referred to as “the refrigerant leakage”) has occurred based on the detection value Vs of therefrigerant leakage detector 500. Thus, the detection value Vs is detection result information indicating whether the refrigerant leakage in thecorresponding valve unit 200 has occurred. - The
unit controller 600 is configured to control operation of thevalve unit 200 via wired communication paths and/or wireless communication paths (partially not shown) between theunit controller 600 and the machineries in thevalve unit 200. In particular, theunit controller 600 is configured to receive the detector signal from therefrigerant leakage detector 500 and determine whether the refrigerant leakage has occurred based on the detector signal. When it is determined that the refrigerant leakage has occurred, theunit controller 600 is configured to output a leakage signal to a later-mentioned central controller. A leakage signal indicates a unit ID (identification) of thevalve unit 200 in which theleakage detector 500 is disposed, and indicates that the refrigerant leakage has occurred in thevalve unit 200 of the unit ID indicated by the leakage signal. In other words, a leakage signal is detection result information indicating whether the refrigerant leakage in thecorresponding valve unit 200 has occurred. - The
unit controller 600 is also configured to receive a later mentioned damper open command from the central controller. When theunit controller 600 has received the damper open command designating the unit ID of thevalve unit 200 to which theunit controller 600 belongs to, control thedamper 440 to open. - The
unit controller 600 may be further configured to switch the open/closed state of each of the low-pressuregas control valves 361 and high-pressuregas control valves 362, and/or control the opening degree of each of the expansion mechanisms 363 (seeFIG. 2 ) such that desired cooling/heating operation can be performed in each of the utilization-side units 120 (seeFIG. 1 ). - For instance, for the utilization-
side unit 120 which should perform cooling operation, the corresponding low-pressuregas control valve 361 is opened and the corresponding high-pressuregas control valve 362 andexpansion mechanism 363 are closed. For the utilization-side unit 120 which should perform heating operation, the corresponding high-pressuregas control valve 362 andexpansion mechanism 363 are opened and the corresponding low-pressuregas control valve 361 is closed. Theunit controller 600 may perform such an operation based on signals which indicate the desired operation modes of the corresponding utilization-side units 120. Such signals may be sent from the heatsource-side unit 110, the corresponding utilization-side units 120, and/or an information output device (not shown) used by the monitoring/maintenance person. - The
unit controller 600 may be separated into a first controller having the functions for controlling themulti branch selector 300 and a second controller having the functions for determining the refrigerant leakage, controlling thedamper 440. In this case, it is also preferable that the first and second controllers have different electricity sources. - The
unit controller 600 includes an arithmetic circuit such as a CPU (Central Processing Unit), a work memory used by the CPU such as a RAM (Random Access Memory), and a recording medium storing control programs and information used by the CPU such as a ROM (Read Only Memory), although they are not shown. Theunit controller 600 is configured to perform information processing and signal processing by the CPU executing the control programs to control the operation of thevalve unit 200. - The
casing 400, thefirst opening 420, thesecond opening 430, thedamper 440, theinsulators 450, therefrigerant leakage detector 500, and theunit controller 600 are part of the safety system of theair conditioning system 100. - (Configuration of Safety System)
-
FIG. 3 is a schematic configuration diagram of the safety system according to the first embodiment. - As shown in
FIG. 3 , thesafety system 700 of theair conditioning system 100 according to the first embodiment comprises the first to third valve units 200_1, 200_2, 200_3, first to third individual ducts 710_1 to 710_3, a sharedduct 720, aventilator 730, and acentral controller 800. The first to third valve units 200_1, 200_2, 200_3 have the first to third internal spaces 401_1, 401_2, 401_3 of the first to third casings 400_1, 400_2, 400_3, respectively. Here, themulti branch selectors 300 of the first to third valve units 200_1, 200_2, 200_3 (seeFIG. 2 ) are omitted. - The first to third individual ducts 710_1 to 710_3 correspond to the first to third valve units 200_1, 200_2, 200_3, respectively. The first to third individual ducts 710_1 to 710_3 have a substantially same configuration with respect to the corresponding
individual duct 710. Thus, in the following descriptions, the term “theindividual duct 710” means any one of the first to third individual ducts 710_1 to 710_3. Theindividual duct 710 is connected to thesecond opening 430 of thecasing 400 of thecorresponding valve unit 200 at one end of theindividual duct 710. Theindividual duct 710 is further connected to the sharedduct 720 at another end of theindividual duct 710. In other words, the first to third individual ducts 710_1 to 710_3 are connected to the sharedduct 720 in common. - The
ventilator 730 is disposed to the sharedduct 720 at or close to one end (hereinafter referred to as “the second end”) of the sharedduct 720, and configured to draw air in the sharedduct 720 towards the second end. It is preferable that the second end of the sharedduct 720 is open to an outdoor space. It is also preferable that theventilator 730 is disposed at the second end as shown inFIG. 3 . The operation of theventilator 730 is controlled by thecentral controller 800. For instance, theventilator 730 starts operating when theventilator 730 has received a ventilator start command from thecentral controller 800. Theventilator 730 may be a fan. Theventilator 730 may be provided with a check air damper which is configured to prevent an air from passing through theventilator 730 when theventilator 730 is not in operation. - The shared
duct 720 is connected to the first to third individual ducts 710_1 to 710_3 on a side of another end (hereinafter referred to “the first end”) of the sharedduct 720 with respect to theventilator 730. Thus, the whole structure of the first to third individual ducts 710_1 to 710_3 and the sharedduct 720 forms a branching duct. Any one of the branching parts of this structure may be deemed as the first end of the sharedduct 720. For instance, the part between the point branching towards the first valve unit 200_1 and the point branching towards the second valve unit 200_2 may be deemed as any one of a part of the sharedduct 720, a part of second individual duct 710_2, and a part of third individual duct 710_3. - Hence, the first to third individual ducts 710_1 to 710_3 form a connection structure which connects the first to third internal spaces 4011, 401_2, 401_3 via the first to third second openings 430_1, 4302, 4303, respectively. As for the
first openings 420, an extension duct may be connected to each of all or part of thefirst openings 420 on the outer side of thecorresponding casing 400. - When any one of the first to third dampers 440_1, 440_2, 440_3 is open, an air path AP can be formed that extends from an external space outside the corresponding
casing 400 to theventilator 730. This air path AP passes through thefirst opening 420 with thedamper 440 open, the correspondinginternal space 401,second opening 430 andindividual duct 710, and the sharedduct 720. If theventilator 730 operates in this state, the air in theinternal space 401 of thecasing 400 with thedamper 440 open is discharged by the suction force of theventilator 730. Meanwhile, as for thecasing 400 with thedamper 440 closed, the above air path AP is not formed. Thus, even if theventilator 730 operates, the air in theinternal space 401 of thecasing 400 with thedamper 440 closed is not discharged by the suction force of theventilator 730.FIG. 3 depicts a situation where only the first damper 440_1 is open. - Hence, the shared
duct 720 and theventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from theinternal space 401 of thecasing 400 with thedamper 440 open. - The
central controller 800 is disposed in the heatsource-side unit 110 (seeFIG. 1 ), for instance. Thecentral controller 800 may be a part of a system controller (not shown) for controlling an air conditioning operation of theair conditioning system 100. - The
central controller 800 is connected to the first to third unit controllers 6001, 600_2, 600_3 and theventilator 730 via acommunication path 801. Thecommunication path 801 may serially connect the first to third unit controllers 600_1, 600_2, 600_3 and theventilator 730 to thecentral controller 800 as shown inFIG. 3 by means of a wired and/or wireless communication. - When a refrigerant leakage has occurred in any one of the first to third valve units 200_1, 200_2, 200_3, the
central controller 800 is configured to control theventilator 730 to start operating (turn ON). Moreover, thecentral controller 800 is configured to, in cooperation with the first to third unit controllers 600_1, 600_2, 600_3, identify in which of the first to third valve units 200_1, 200_2, 200_3 the refrigerant leakage has occurred, and control the first to third dampers 440_1, 440_2, 440_3. More specifically, thecentral controller 800 is configured to control the first to third dampers 440_1, 440_2, 440_3 such that, when theventilator 730 operates due to the occurrence of the refrigerant leakage, thedamper 440 of thevalve unit 200 of refrigerant leakage is open while theother dampers 440 are closed. Thereby, the discharge structure mentioned above can discharge air from theinternal space 401 of thecasing 400 with refrigerant leakage. - The
central controller 800 includes an arithmetic circuit such as a CPU, a work memory used by the CPU such as a RAM, and a recording medium storing control programs and information used by the CPU such as a ROM, although they are not shown. Thecentral controller 800 is configured to perform information processing and signal processing by the CPU executing the control programs to control at least the operation of the safety system of theair conditioning system 100. - (Operation of Unit Controller)
- The
unit controller 600 is configured to detect an occurrence of a refrigerant leakage in thecorresponding casing 400. Theunit controller 600 is further configured to, when the refrigerant leakage has occurred, inform of the detection result to thecentral controller 800 and control thecorresponding damper 440 to open which is normally closed under control of thecentral controller 800. More specifically, theunit controller 600 is configured to perform the following operation. -
FIG. 4 is a flow chart indicating an operation performed by theunit controller 600. - In step S1010, the
unit controller 600 acquires the detection value Vs from the detector signal outputted from therefrigerant leakage detector 500. Theunit controller 600 may passively receive the detector signal which is continuously or regularly outputted from therefrigerant leakage detector 500, or actively request therefrigerant leakage detector 500 to output the detector signal regularly. The obtained detection value Vs basically reflects the variation in the concentration of the refrigerant in thecasing 400. - In step S1020, the
unit controller 600 compares the detection value Vs acquired and a detection value threshold Vth, and determines whether the detection value Vs is less than the detection value threshold Vth. Theunit controller 600 may obtain a moving average value of the detection values Vs in a certain time length to use the moving average value as the detection value Vs which is compared with the detection value threshold Vth. - The detection value threshold Vth is stored in the
unit controller 600 in advance. The detection value threshold Vth may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the detection value threshold Vth is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the refrigerant used. - If the detection value Vs is equal to or greater than the detection value threshold Vth (S1020: No), the
unit controller 600 proceeds to later-mentioned step S1030. If the detection value Vs is less than the detection value threshold Vth (S1020: Yes), theunit controller 600 proceeds to later-mentioned step S1040. It can be said that therefrigerant leakage detectors 500 transmits detection result information to thecentral controller 800 via the correspondingunit controller 600 by steps from S1010 to S1030. - In step S1030, the
unit controller 600 transmits to thecentral controller 800 a leakage signal indicating the unit ID of thevalve unit 200 to which theunit controller 600 belongs (hereinafter referred to as “the own unit ID”). Theunit controller 600 may directly send a leakage signal to thecentral controller 800 or indirectly send a leakage signal to thecentral controller 800 via one or more ofother unit controllers 600. In the latter case, theunit controllers 600 sends the leakage signal to theother unit controller 600, and the leakage signal is relayed in series by theunit controllers 600. For instance, when thecommunication path 801 is arranged as shown inFIG. 3 , the unit controller 600_3 of the third valve unit 200_3 directly sends a leakage signal to thecentral controller 800, and the unit controller 600_2 of the second valve unit 200_2 sends a leakage signal to thecentral controller 800 via the unit controller 600_3 of the third valve unit 200_3. - The
unit controller 600 may determine the controller to which the leakage signal should be sent based on network information regarding the communication path between theunit control 600 and thecentral controller 800. The network information may be stored in theunit controller 600 in advance, or acquired by making an inquiry to the other unit controller orcontrollers 600 and/or thecentral controller 800. - In step S1040, the
unit controller 600 determines whether a leakage signal has been received at theunit controller 600 that was transmitted from theother unit controller 600. If a leakage signal has been received (S1040: Yes), theunit controller 600 proceeds to step S1050. If a leakage signal has not been received (S1040: No), theunit controller 600 proceeds to later-mentioned step S1060. - In step S1050, the
unit controller 600 forwards the received leakage signal towards thecentral controller 800. Theunit controller 600 may directly send the received leakage signal to thecentral controller 800 or indirectly send the received leakage signal to thecentral controller 800 via one or more ofother unit controllers 600. Theunit controller 600 may determine the controller to which the received leakage signal should be sent based on the network information mentioned above. - In step S1060, the
unit controller 600 determines whether a ventilator start command has been received at theunit controller 600. As mentioned later, a ventilator start command is a command transmitted from thecentral controller 800. If a ventilator start command has been received (S1060: Yes), theunit controller 600 proceeds to step S1070. If a ventilator start command has not been received (S1060: No), theunit controller 600 proceeds to later-mentioned step S1080. - In step S1070, the
unit controller 600 forwards the received ventilator start command towards theventilator 730. Theunit controller 600 may directly send the received ventilator start command to theventilator 730 or indirectly send the received ventilator start command to theventilator 730 via one or more ofother unit controllers 600. Theunit controller 600 may determine theunit controller 600 to which the ventilator start command should be sent based on the network information mentioned above. - In step S1080, the
unit controller 600 determines whether a damper open command has been received at theunit controller 600 that was transmitted from thecentral controller 800. If a damper open command has been received (S1080: Yes), theunit controller 600 proceeds to step S1090. If a damper open command has not been received (S1080: No), theunit controller 600 proceeds to later-mentioned step S1110. - In step S1090, the
unit controller 600 further determines whether the received damper open command designates thevalve unit 200 to which theunit controller 600 belongs (hereinafter referred to as “the own valve unit”) as thevalve unit 200 which should open itsdamper 440. Theunit controller 600 may make this determination based on whether the received damper open command designates the own unit ID. If the damper open command does not designate the own valve unit (S1090: No), theunit controller 600 proceeds to step S1100. If the damper open command designates the own valve unit (S1090: Yes), theunit controller 600 proceeds to later-mentioned step S1120. - In step S1100, the
unit controller 600 forwards the received damper open command towards theother unit controller 600 which has not received the damper open command. Theunit controller 600 may determine theunit controller 600 to which the received damper open command should be sent based on the network information mentioned above. - In step S1110, the
unit controller 600 determines whether termination of operation has been designated. The designation may be made by a user operation, another device, or theunit controller 600 itself. If termination of the operation has not been designated (S1110: No), theunit controller 600 goes back to step S1010 to repeat the above acquisition and determination steps. If termination of the operation has been designated (S1110: Yes), theunit controller 600 terminates its operation. - In step S1120, the
unit controller 600 controls thedamper 440 of theown valve unit 200 to open, and then terminates its operation. For instance, theunit controller 600 controls the state of thedamper 440 by controlling a supply of electricity thereto. Theunit controller 600 may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to theunit controller 600. - Steps S1040 and S1050 may be performed before steps S1010 to S1030. Steps S1080 to S1100 may also be performed before steps S1040 and S1050.
- By the above operation, when a refrigerant leakage has occurred in the
own valve unit 200, each of theunit controllers 600 can report to thecentral controller 800 the occurrence of the refrigerant leakage, and control thedamper 440 of theown valve unit 200 to open when it has been instructed by thecentral controller 800. - (Operation of Central Controller)
- The
central controller 800 is configured to control theventilator 730 to start operating when an occurrence of the refrigerant leakage in any one of thevalve units 200 has been reported. Thecentral controller 800 is further configured to control thedamper 440 in thevalve unit 200 of refrigerant leakage to open by instructing that to thecorresponding unit controller 600. More specifically, thecentral controller 800 is configured to perform the following operation. -
FIG. 5 is a flow chart indicating an operation performed by thecentral controller 800. - In step S2010, the
central controller 800 determines whether a leakage signal has been received at thecentral controller 800 that was transmitted from one of theunit controllers 600. This leakage signal is a signal originated from theunit controller 600 in the step S1030 ofFIG. 4 . If a leakage signal has been received (S2010: Yes), thecentral controller 800 proceeds to later-mentioned step S2030. If a leakage signal has not been received (S2010: No), thecentral controller 800 proceeds to later-mentioned step S2020. - In step S2020, the
central controller 800 determines whether termination of operation has been designated. The designation may be made by a user operation, another device, or thecentral controller 800 itself. If termination of the operation has not been designated (S2020: No), thecentral controller 800 goes back to step S2010 to repeat the above determination step. If termination of the operation has been designated (S2020: Yes), thecentral controller 800 terminates its operation. - In step S2030, the
central controller 800 obtains the unit ID indicated by the received leakage signal from the leakage signal. This unit ID indicates the originator of the leakage signal, i.e. thevalve unit 200 of refrigerant leakage. Thereby, thecentral controller 800 can identify thevalve unit 200 of refrigerant leakage. - In step S2040, the
central controller 800 transmits a ventilator start command to theventilator 730 to control theventilator 730 to start operating. The ventilator start command may be directly sent to theventilator 730 or relayed to it by the unit controller orcontrollers 600. For instance, thecentral controller 800 controls the operation of theventilator 730 by controlling a supply of electricity thereto. - In step S2050, the
central controller 800 transmits, to at least the originator of the received leakage signal, a damper open command designating the originator as thevalve unit 200 which should open itsdamper 440. Thecentral controller 800 may make this designation by using the unit ID of the originator. The damper open command may be directly sent to theunit controller 600 of thevalve unit 200 of refrigerant leakage or relayed to it in series by the unit controller orcontrollers 600. Then, thecentral controller 800 terminates its operation. It can be said that thecentral controller 800 transmits the damper open command to thedamper 440 of thevalve unit 200 of refrigerant leakage via the correspondingunit controllers 600 by step S2050 and step S1120 ofFIG. 4 . - The
central controller 800 may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to thecentral controller 800. In this case, it is preferable that the alarm information indicates thevalve unit 200 of refrigerant leakage by outputting the unit ID of thevalve unit 200 of refrigerant leakage or other information from which thevalve unit 200 of refrigerant leakage can be identified, e.g. information indicating the location of thevalve unit 200. - Step S2040 may be performed before step S2030, and step S2050 may also be performed before step S2040. Yet, it is preferable to start operation of the
ventilator 730 before opening thecorresponding damper 440. Thecentral controller 800 may control the timing of transmission of the damper open command such that thecorresponding damper 440 opens only when the performance of theventilator 730 has reached a level high enough to prevent the internal air in thecorresponding casing 400 from outflowing through thefirst opening 420 even if thedamper 440 is opened. - By the above operation, when a refrigerant leakage in any one of the
valve units 200 has occurred, thecentral controller 800 can control theventilator 730 to start operating and control thedamper 440 in thevalve unit 200 of refrigerant leakage to open in cooperation with theunit controllers 600. - (Advantageous Effect of First Embodiment)
- As described above, the
air conditioning system 100 according to the first embodiment includes a plurality of themulti branch selectors 300 and has thesafety system 700. Thesafety system 700 includes a plurality of thecasings 400 accommodating themulti branch selectors 300, respectively, and each provided with therefrigerant leakage detector 500. Thesafety system 700 also includes a plurality ofindividual ducts 710 which function as the connection structure connecting theinternal spaces 401 of thecasings 400 via thesecond openings 430 thereof. Thesafety system 700 further includes the sharedduct 720 and theventilator 730 as the discharge structure connected to the connection structure. The discharge structure is configured to, when an occurrence of the refrigerant leakage has been detected, configured to discharge air from theinternal space 401 of thecasing 400 in which the refrigerant leakage has occurred. - Thereby, when a refrigerant leakage has occurred in any one of the
multi branch selectors 300, thesafety system 700 can properly and promptly detect this refrigerant leakage, and discharge the air in thecasing 400 covering the multi branch selector to the external space to decrease the concentration of the leaked refrigerant in theinternal space 401 of thecasing 400. Thus, it is possible to improve safety of theair conditioning system 100 regarding refrigerant leakage in themulti branch selectors 300 which are arranged in separate locations. Moreover, the air in the other casing orcasings 400 are not discharged. Hence, the air volume capacity required of theventilator 730 can be decreased, and thereby the dimension of theventilator 730 and/or the number of theventilator 730 can be reduced. - (Modifications of First Embodiment)
- In the first embodiment explained above, the
unit controllers 600 are serially connected to thecentral controller 800. However, all or part of theunit controllers 600 may be individually connected to thecentral controller 800 via individual communication paths. Regarding the individually connectedunit controller 600, thecentral controller 800 can distinguish theunit controller 600 from the other unit controller orcontrollers 600 by the individual communication path, and transmit the damper open command appropriately just by simply responding to the sender of the leakage signal. - In the first embodiment, a leakage signal indicates the unit ID of the
valve unit 200 in which a refrigerant leakage has occurred. Yet, if theunit controller 600 is configured to record transmission of a leakage signal and identify a damper open command as a response to the transmitted leakage signal only when the damper open command has been received within a predetermined time of the transmission, a leakage signal need not necessarily indicate any unit ID. If thecentral controller 800 and theunit controllers 600 communicate with each other by using different timeslots allocated to theunit controllers 600, a leakage signal need not necessarily indicate any unit ID, either. - Alternatively, the
unit controller 600 may control thedamper 440 of theown valve unit 200 to open when theunit controller 600 has received detection result information indicating a refrigerant leakage in theown valve unit 200 has occurred. In this case, thecentral controller 800 need not transmit a damper open command to theunit controller 600. Theunit controller 600 may control thedamper 440 to open when a predetermined time has lapsed after transmitting the leakage signal, such that thedamper 440 opens after theventilator 730 started operating. - The connection route of the
communication path 801 is not limited to the route shownFIG. 3 . For instance, all or part of theunit controllers 600 and theventilator 730 may be directly connected to thecentral controller 800 via individual wired/wireless communication paths. - (Configuration of Safety System)
- In the first embodiment of the present invention mentioned above, the
internal spaces 401 of thecasings 400 are connected to each other in parallel. On the other hand, in a second embodiment of the present invention explained hereinafter, theinternal spaces 401 of thecasings 400 are connected to each other in series. - A safety system according to the second embodiment may also be applied to an air conditioning system having the same configuration as the air conditioning system of the first embodiment. The configuration of each of the valve units of the safety system according to the second embodiment may be the same as that of the first embodiment. The same reference signs as the first embodiment are appended to elements and steps which are substantially the same as those of the first embodiment, and the explanations thereof are omitted.
-
FIG. 6 is a schematic configuration diagram of a safety system according to the second embodiment. - As shown in
FIG. 6 , thesafety system 700 a of the air conditioning system 100 (seeFIG. 1 ) according to the second embodiment comprises the first to third valve units 200_1, 200_2, 200_3, first and second connecting ducts 740 a_1, 740 a_2, a sharedduct 720 a, theventilator 730, and acentral controller 800 a. Thesafety system 700 a does not have theindividual ducts 710 of the first embodiment. - The first connecting duct 740 a_1 is connected on one side to the second opening 430_2 of the casing 400_2 of the second valve unit 200_2, and connected on another side to the first opening 420_1 of the casing 400_1 of the first valve unit 200_1. The second connecting duct 740 a_2 is connected on one side to the second opening 430_3 of the casing 400_3 of the third valve unit 2003, and connected on another side to the first opening 420_2 of the casing 400_2 of the second valve unit 200_2.
- Hence, the first and second connecting ducts 740 a_1, 740 a_2 form a connection structure which connects the first to third internal spaces 401_1, 401_2, 401_3 via the first openings 4201, 4202 and the second openings 4302, 4303.
- To the second opening 430_1 of the casing 400_1 of the first valve unit 200_1, the shared
duct 720 a is connected. Theventilator 730 is disposed to the sharedduct 720 a at or close to one end (hereinafter referred to as “the second end”) of the sharedduct 720, and configured to draw air in the sharedduct 720 a towards the second end. It is preferable that the second end of the sharedduct 720 a is open to an outdoor space. It is also preferable that theventilator 730 is disposed at the second end as shown inFIG. 6 . The static pressure capacity of theventilator 730 of the second embodiment may be different from theventilator 730 of the first embodiment. To the first opening 420_3 of the third valve unit 200_3, which is thefirst opening 420 farthest from theventilator 730 along the air path AP extending over thecasings 400 and leading to theventilator 730, an extension duct may be connected on the outer side of the corresponding casing 400_3. - Hence, the shared
duct 720 a and theventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from theinternal spaces 401 of thecasings 400 when all thedampers 440 are open. - The position, the connection to the other elements, and the physical configuration of the
central controller 800 a may be the same as those of thecentral controller 800 according to the first embodiment. Yet, the operation of thecentral controller 800 a is slightly different from that of thecentral controller 800 of the first embodiment. Thecentral controller 800 a is configured to control thedampers 440 of all thevalve units 200 to be open when theventilator 730 operates due to an occurrence of the refrigerant leakage. - (Operation of Central Controller)
- When an occurrence of the refrigerant leakage in any one of the
valve units 200 has been reported, thecentral controller 800 a is configured to control theventilator 730 to start operating similarly to the first embodiment. Meanwhile, thecentral controller 800 a is configured to control thedampers 440 of all thevalve units 200 to open. -
FIG. 7 is a flow chart indicating an operation performed by thecentral controller 800 a. - As shown in
FIG. 7 , thecentral controller 800 a performs the same steps as steps S2010 to S2040 ofFIG. 5 . Yet, thecentral controller 800 a perform step S2050 a instead of step S2050 ofFIG. 5 . - In step S2050 a, the
central controller 800 a transmits a damper open command to all thevalve units 200. More specifically, thecentral controller 800 a transmits a damper open command designating all thevalve units 200 including the originator of the leakage signal and serially connected to this originator. Thecentral controller 800 a may make this designation by using the unit IDs of thevalve units 200. Then, thecentral controller 800 terminates its operation. Thecentral controller 800 a may output alarm information and/or control the timing of transmission of the damper open command as mentioned in the first embodiment. - When all the first to third dampers 440_1, 440_2, 440_3 (see
FIG. 6 ) are open, an air path AP can be formed that extends from an external space outside the casing 400_3 of the third valve unit 200_3 to theventilator 730. This air path AP passes through the first opening 420_3, the internal space 401_3, and the second opening 430_3 of the third valve unit 2003, the second connecting duct 740 a_2, the first opening 420_2, the internal space 401_2, and the second opening 430_2 of the second valve unit 200_2, the first connecting duct 740 a_1, the first opening 420_1, the internal space 401_1, and the second opening 430_1 of the first valve unit 200_1, and the sharedduct 720 a. If theventilator 730 operates in this state, the air in theinternal spaces 401 of thecasings 400 of the first to third valve units 200_1, 200_2, 200_3 are discharged by the suction force of theventilator 730. - (Advantageous Effect of Second Embodiment)
- Accordingly, the
air conditioning system 100 according to the second embodiment includes a plurality of themulti branch selectors 300 and has thesafety system 700 a. Thesafety system 700 a includes a plurality of thecasings 400 accommodating themulti branch selectors 300, respectively, and each provided with therefrigerant leakage detector 500. Thesafety system 700 a also includes a plurality of connectingducts 740 a which function as the connection structure connecting theinternal spaces 401 of thecasings 400 via thefirst openings 420 andsecond openings 430 thereof. Thesafety system 700 a further includes the sharedduct 720 a and theventilator 730 as the discharge structure connected to the connection structure. The discharge structure is configured to, when an occurrence of the refrigerant leakage has been detected, discharge air from theinternal spaces 401 of all thecasings 400 including thecasing 400 in which the refrigerant leakage has occurred. - Thereby, when a refrigerant leakage has occurred in any one of the
multi branch selectors 300, thesafety system 700 a can properly and promptly detect this refrigerant leakage, and discharge the air in thecasing 400 covering themulti branch selector 300 to the external space to decrease the concentration of the leaked refrigerant in theinternal space 401 of thecasing 400. Thus, it is possible to improve safety of the air conditioning system regarding refrigerant leakage from valves in themulti branch selectors 300 which are arranged in separate locations. Moreover, it is possible to reduce the total length of ducts for connecting thecasings 400 to theventilator 730 compared with the configuration of the first embodiment, and thereby reduce the installation cost of the system. - (Modifications of Second Embodiment)
- In the second embodiment explained above, the
ventilator 730 is connected to one of thecasings 400 via the sharedduct 720 a. Yet, the sharedduct 720 a with short length and theventilator 730 may be integrated as a single element. If one of the casings has a part exposed to the outdoor space, such a single element may be disposed in this part. - In the second embodiment, a leakage signal indicates the originator of leakage signal by the unit ID of the
valve unit 200 in which a refrigerant leakage has occurred, and thecentral controller 800 a identifies thevalve unit 200 of refrigerant leakage. Yet, a leakage signal need not necessarily indicate the originator of leakage signal much less the unit ID, and thecentral controller 800 a need not necessarily identify thevalve unit 200 of refrigerant leakage. - The connection route of the
communication path 801 is not limited to the route shownFIG. 6 . For instance, all or part of theunit controllers 600 and theventilator 730 may be directly connected to thecentral controller 800 a via individual wired/wireless communication paths. - As a third embodiment of the present invention, a configuration is explained in which the configurations according to the first and second embodiments are combined. A safety system according to the third embodiment may be applied to an air conditioning system having the same configuration as the air conditioning systems of the first and second embodiments. The configuration of each of valve units of the safety system according to the third embodiment may be the same as that of the first and second embodiments. The same reference signs as the first and second embodiments are used to elements and steps which are substantially the same as those of the first and second embodiments, and the explanations thereof are omitted.
-
FIG. 8 is a schematic configuration diagram of the safety system according to the third embodiment. - As shown in
FIG. 8 , thesafety system 700 b of the air conditioning system 100 (seeFIG. 1 ) according to the third embodiment comprises the first to third valve units 200_1, 200_2, 200_3, the first and second individual ducts 7101, 7102, the second connecting duct 740 a_2, a sharedduct 720 b, theventilator 730, and acentral controller 800 b. Thesafety system 700 b does not have the third individual duct 710_3 of the first embodiment and the first connecting duct 740 a_1 of the second embodiment. - The first individual duct 710_1 connects the second opening 430_1 of the casing 400_1 of the first valve unit 200_1 to the shared
duct 720 b. The second individual duct 710_2 connects the second opening 430_2 of the casing 400_2 of the second valve unit 200_2 to the sharedduct 720 b. The second connecting duct 740 a_2 connects the second opening 430_3 of the casing 400_3 of the third valve unit 200_3 to the first opening 4202 of the casing 400_2 of the second valve unit 200_2. - Hence, the first and second individual ducts 7101, 710_2 and the second connecting duct 740 a_2 form a connection structure which connects the first to third internal spaces 401_1, 401_2, 401_3 via the first opening 4202 and the second openings 430_1, 430_2, 430_3.
- The
ventilator 730 is disposed to the sharedduct 720 b at or close to one end (hereinafter referred to as “the second end”) of the sharedduct 720 b, and configured to draw air in the sharedduct 720 b towards the second end. It is preferable that theventilator 730 is disposed at the second end as shown inFIG. 8 . The static pressure capacity of theventilator 730 may be different from theventilators 730 according to the first and second embodiments. - Hence, the shared
duct 720 b and theventilator 730 form a discharge structure which is connected to the connection structure mentioned above and configured to discharge air from the internal space 401_1 of the casing 400_1 of the first valve unit 200_1 when the damper 440_1 of the first valve unit 200_1 is open, and discharge air from the internal spaces 4012, 401_3 of the casings 400_2, 400_3 of the second and third valve units 200_2, 200_3 when both the dampers 440_2, 440_3 of the second and third valve units 200_2, 200_3 are open. - The position, the connection to the other elements, and the physical configuration of the
central controller 800 b may be the same as those of thecentral controller 800 according to the first embodiment. Thecentral controller 800 b is also configured to perform basically the same operation as thecentral controller 800 according to the first embodiment. Thecentral controller 800 b controls the damper ordampers 440 of all or part of thevalve units 200 to be open when theventilator 730 operates due to an occurrence of the refrigerant leakage. - Yet, the operation of the
central controller 800 b is slightly different from that of thecentral controllers central controller 800 b has a grouping table which defines the relationship between each of thevalve units 200 anddampers 440 to be opened when a refrigerant leakage has occurred in thevalve unit 200. Thecentral controller 800 b is configured to determine thevalve unit 200 which should open itsdamper 440 based on the grouping table. -
FIG. 9 is the grouping table used by thecentral controller 800 b. - As shown in
FIG. 9 , the grouping table 910 b associates adestination 912 b of a damper open command with each of thevalve units 200 as anoriginator 911 b of a leakage signal with the valve unit orunits 200. Thedestination 912 b is the valve unit orunits 200 in which the damper ordampers 440 should be opened when a refrigerant leakage has occurred in thevalve unit 200 as theoriginator 911 b. - In other words, the grouping table 910 b indicates groups of the
valve units 200. In the group including a plurality of thevalve units 200, theinternal spaces 401 of thecasings 400 are connected to theventilator 730 in series. Between the different groups, theinternal spaces 401 of thecasings 400 are connected to theventilator 730 in parallel. Thevalve units 200 may be defined in the grouping table 910 b by their unit IDs. - For instance, with the unit ID “U1” of the first valve unit 200_1 as the
originator 911 b, only the unit ID “U1” of the first valve unit 200_1 as thedestination 912 b is associated. With each of the unit IDs “U2” and “U3” of the second and third valve units 200_2, 200_3 as theoriginator 911 b, the unit IDs “U2” and “U3” of the second and third valve units 200_2, 200_3 as thedestination 912 b are associated. The grouping table 910 b is stored in thecentral controller 800 b in advance. Thecentral controller 800 b may accept a manually setting of the grouping table 910 b. - Yet, the structure of the grouping table 910 b is not limited to that shown in
FIG. 9 . For instance, the grouping table 910 b may simply define groups of thevalve units 200 such that thevalve units 200 connected to theventilator 730 in series by the connection structure form a group. Thesingle valve unit 200 to which noother valve unit 200 is connected in series with respect to theventilator 730 by the connection structure may also form a group. Each group may be defined by using identifications of theunit controllers 600. - The
central controller 800 b performs substantially the same steps as steps S2010 to S2050 ofFIG. 5 . Yet, in step S2030 or S2050, thecentral controller 800 b determines thevalve unit 200 which should open itsdamper 440 based on theoriginator 911 b of the received leakage signal and the grouping table 910 b. Thus, when the refrigerant leakage has occurred in the first valve unit 200_1 for instance, thecentral controller 800 b transmits a damper open command designating the first valve unit 200_1. - Thereby, as depicted in
FIG. 8 , only the damper 4401 of the first valve unit 200_1 is opened to create an air path AP passing through the first opening 420_1, internal space 401_1, second opening 430_1 of the first valve unit 200_1, the first individual duct 710_1, and the sharedduct 720 b. The dampers 440_2, 440_3 of the second and third valve units 200_2, 200_3 are kept closed. Thus, theventilator 730 draws air from the internal space 401_1 of the first valve unit 200_1, but not air from the internal spaces 401_2, 4013 of the second and third valve units 200_2, 200_3. - Accordingly, the
air conditioning system 100 according to the third embodiment includes thesafety system 700 b in which thecasings 400 serially connected to each other are further connected to theother casing 400 in parallel. Even with such a connection structure with a complicated configuration, it is possible to discharge air from theinternal space 401 of thecasing 400 in which the refrigerant leakage has occurred, while reducing static pressure capacity required of theventilator 730. - The modifications mentioned in the first and second embodiments may be applied to a
safety system 700 b according to the third embodiment. It should be noted that the grouping table 910 b and the determination of thevalve unit 200 to open itsdamper 440 based on the grouping table 910 b mentioned above may also be applied to the first and second embodiments. - The connection route of the
communication path 801 is not limited to the route shownFIG. 8 . For instance, all or part of theunit controllers 600 and theventilator 730 may be directly connected to thecentral controller 800 b via individual wired/wireless communication paths. - Other patterns of combination of the configurations according to the first and second embodiments may also be considerable. For instance, to the
first opening 420 of thefirst valve unit 200, the second openings 430_2, 430_3 of the second and third valve units 200_2, 200_3 may be connected in parallel by a branched duct. In such a configuration, the branched duct functions as both the individual ducts 7102, 710_3 of the first embodiment and the connecting ducts 740 a_1, 740 a_2 of the second embodiment. - In any case, the
central controller 800 b is configured to open all the damper ordampers 440 existing on a line which extends from theventilator 730, passes through theinternal space 401 of thecasing 400 with refrigerant leakage, and reaches the external space of thecasing 400. It is preferable that thecentral controller 800 b keeps the other damper or dampers closed. - As a fourth embodiment of the present invention, a configuration is explained in which there are a plurality of sets of the connection structure and the discharge structure. A safety system according to the fourth embodiment may be applied to an air conditioning system having the same configuration as the air conditioning systems of the first to third embodiments. The configuration of each of valve units of the safety system according to the fourth embodiment may be the same as that of the first to third embodiments. The same reference signs as the first to third embodiments are used to elements and steps which are substantially the same as those of the first to third embodiments, and the explanations thereof are omitted.
-
FIG. 10 is a schematic configuration diagram of the safety system according to the fourth embodiment. - As shown in
FIG. 10 , thesafety system 700 c of the air conditioning system 100 (seeFIG. 1 ) according to the fourth embodiment comprises a first section 701 c_1, a second section 701 c_2, and acentral controller 800 c. - The first section 701 c_1 includes the first and second valve units 200_1, 200_2, the first and second individual duct 710_1, 7102, the first shared duct 720_1, and the first ventilator 730_1. Yet, the number of the
valve units 200 in each section 701 c is not limited to two, and may be one, three, or more. Similarly to the first embodiment, the first and second valve units 200_1, 200_2 are connected to each other in parallel and commonly connected to the first shared duct 720_1 via the first and second individual duct 710_1, 710_2. The unit controllers (not shown inFIG. 10 , seeFIG. 3 ) of the first and second valve units 200_1, 200_2 and the first ventilator 730_1 are connected to thecentral controller 800 c by thecommunication path 801. - The second section 701 c_2 includes the third and fourth valve units 200_3, 200_4, the connecting
duct 740 a, the second shared duct 7202, and the second ventilator 730_2. Similarly to the second embodiment, the third and fourth valve units 200_3, 200_4 are connected to each other via the connectingduct 740 a and connected to the second shared duct 720_2 in series. The unit controllers (not shown inFIG. 10 , seeFIG. 6 ) of the third and fourth valve units 200_3, 200_4 and the second ventilator 730_2 are connected to thecentral controller 800 c by thecommunication path 801. - The position, the connection to the other elements, and the physical configuration of the
central controller 800 c may be the same as those of thecentral controller 800 b according to the third embodiment. Thecentral controller 800 c is also configured to perform basically the same operation as thecentral controller 800 b according to the third embodiment. Thecentral controller 800 c controls the damper or dampers 440 (not shown inFIG. 10 , seeFIGS. 3 and 6 ) of all or part of thevalve units 200 to be open when theventilator 730 operates due to an occurrence of the refrigerant leakage. Thecentral controller 800 c determines thevalve unit 200 which should open itsdamper 440 based on the grouping table similarly to thecentral controller 800 b of the third embodiment. - Yet, the
central controller 800 c uses a different type of a grouping table to further determine the ventilator which should start operating. More specifically, thecentral controller 800 c is configured to control the ventilator of only the section in which a refrigerant leakage has occurred to start operating. -
FIG. 11 is a grouping table used by thecentral controller 800 c. - As shown in
FIG. 11 , the grouping table 910 c associates, in addition to the destination ordestinations 912 b of a damper open command, aventilator 913 c which should operate with each of thevalve units 200 as anoriginator 911 b of a leakage signal. In other words, the grouping table 910 c indicates the sections 701 c. In each of the sections, theinternal spaces 401 of the valve units 200 (not shown inFIG. 10 , seeFIG. 2 ) are connected to the same ventilator, but not connected to the ventilator of the other section. The ventilators may be defined in the grouping table 910 c by their ventilator IDs. - For instance, with the unit ID “U1” of the first valve unit 200_1 as the
originator 911 b, the unit ID “U1” of the first valve unit 200_1 as thedestination 912 b and a ventilator ID “F1” of the first ventilator 730_1 as theventilator 913 c to operate are associated. With the unit ID “U2” of the second valve unit 200_2 as theoriginator 911 b, the unit ID “U2” of the second valve unit 200_2 as thedestination 912 b and a ventilator ID “F1” of the first ventilator 730_1 as theventilator 913 c to operate are associated. With each of the unit ID “U3” of the third valve unit 200_3 and the unit ID “U4” of the fourth valve unit 200_4 as theoriginator 911 b, the unit IDs “U3” and “U4” of the third and fourth valve units 2003, 200_4 as thedestination 912 b and a ventilator ID “F2” of the second ventilator 730_2 as theventilator 913 c to operate are associated. The grouping table 910 c is stored in thecentral controller 800 c in advance. Thecentral controller 800 c may accept a manually setting of the grouping table 910 c. - Yet, the structure of the grouping table 910 c is not limited to that shown in
FIG. 11 . For instance, the grouping table 910 c may simply define groups of thevalve units 200 such that thevalve units 200 connected to thesame ventilator 730 in series by the connection structure form a group, and associates the group with thecorresponding ventilator 730. Thesingle valve unit 200 to which noother valve unit 200 is connected in series with respect to theventilator 730 by the connection structure may also form a group. Each group may be defined by using identifications of theunit controllers 600. - The
central controller 800 c performs substantially the same steps as steps S2010 to S2050 ofFIG. 5 . Yet, thecentral controller 800 c determines in step S2030 or S2040 the ventilator which should start operating based on the originator of the received leakage signal and the grouping table 910 c, and determines in step S2030 or S2050 the valve unit orunits 200 each of which should open itsdamper 440 based on the originator of the received leakage signal and the grouping table 910 c. - Thus, when the refrigerant leakage has occurred in the first valve unit 200_1 for instance, the
central controller 800 c transmits a ventilator start command to the first ventilator 730_1 for starting its operation, and transmits a damper open command designating the first valve unit 200_1. As a result, only the first ventilator 730_1 among the ventilators operates, and the damper of only the first valve unit 200_1 among thevalve units 200 opens. The ventilator start command may designate the ventilator ID of the ventilator which should start operating. - Accordingly, the
air conditioning system 100 according to the fourth embodiment includes thesafety system 700 c which is sectioned into a plurality of sections 701 c controlled by the commoncentral controller 800 c. Thecentral controller 800 c is configured to, when a refrigerant leakage in any one of thevalve units 200 has occurred, control the ventilator of only the section 701 c in which the refrigerant leakage has occurred to start operating, and control only the damper ordampers 440 which should be opened in order to discharge air from thevalve unit 200 of refrigerant leakage. Thereby, the air discharge can be performed appropriately while reducing electricity consumption. - When the valves of the
air conditioning system 100 are arranged in widely separated locations, extending ducts from all thevalve units 200 to the same common ventilator would result in an increase in the total length of the ducts and static pressure capacity required of the ventilator. Moreover, there might be cases where it is difficult to draw a continuous ducting to cover all thevalve units 200 due to limitations imposed by the installation place. In such a case, it is possible to dispose a plurality of the safety system. However, providing the central controller to each of the safety systems would be uneconomical. Hence, by thesafety system 700 c according to the fourth embodiment, it is possible to improve safety of theair conditioning system 100 regarding refrigerant leakage from valves at a low cost even if the valves are arranged in widely separated locations. - The connection route of the
communication path 801 is not limited to the route shownFIG. 10 . For instance, the third and fourth valve units 200_3, 2004 and the second ventilator 730_2 of the second section 701 c_2 may be connected to thecentral controller 800 c by anothercommunication path 801 independently from the first section 701 c_1, or indirectly connected to thecentral controller 800 c via the unit controller orcontrollers 600 of the first section 701 c_1. All or part of theunit controllers 600 and theventilators 730 may be directly connected to thecentral controller 800 c via individual wired/wireless communication paths. The connection routes of thecasings 400 of thevalve units 200 by ducts are also not limited to the routes shown inFIG. 10 . - (Other Modifications of First to Fourth Embodiments)
- The above-mentioned configurations and operations of the
safety systems - For instance, the
valve unit 200 may have a configuration including the heatsource-sideliquid pipe portion 310, the utilization-sideliquid pipe portions 311, the low-pressuregas pipe portion 320, the low-pressuregas sub pipes 321, the high-pressuregas pipe portion 340, the high-pressuregas sub pipes 341, the utilization-sidegas pipe portions 330, the low-pressuregas control valves 361, and the high-pressuregas control valves 362, but not including all or part of the sets of thebypass pipe 351, therefrigerant heat exchanger 352, and theexpansion mechanism 363. All or part of the gas shut-offvalves 365 may be further omitted. - Moreover, the
air conditioning system 100 may have a heat pump system with a so-called two-pipe configuration. In such a case, the piping accommodated in thecasing 400 would not be themulti branch selector 300. Yet, thevalve unit 200 has at least a liquid refrigerant pipe portion, a gas refrigerant pipe portion, a liquid control valve disposed in the liquid refrigerant pipe portion, and a gas control valve disposed in the gas refrigerant pipe portion. Each of the liquid control valve and the gas control valve may be any type of valve for controlling flow of refrigerant in the corresponding pipe portion. - For instance, any one of the
safety systems valve unit 200 d as shown inFIG. 12 instead of thevalve unit 200 ofFIG. 2 . Compared with the configuration ofFIG. 2 , thevalve unit 200 d as a modification of the present embodiment does not necessarily have the high-pressuregas pipe portion 340, the low-pressuregas sub pipes 321, the high-pressuregas sub pipes 341, thebypass pipes 351, therefrigerant heat exchangers 352, the low-pressuregas control valves 361, the high-pressuregas control valves 362, and theexpansion mechanisms 363. - Furthermore, any one of the above-mentioned valve units may have a configuration in which the heatsource-side
liquid pipe portion 310 and the gas pipe portion orportions side units 120 of theair conditioning system 100 but directed towards only one among the utilization-side units 120. Even in such configurations, each valve disposed in the refrigerant pipe portions within thecasing 400 would be a leakage point of refrigerant, and thus the safety regarding refrigerant leakage should be improved. - The
casing 400 of any one of the above embodiments and modifications may comprise a plurality of casing parts which are attachable to and detachable from each other. In this case, the casing parts may be structured such that each of thepipe apertures 410 is formed between two or more of the adjoining casing parts. Thereby, each extending pipe can easily be fitted into the correspondingpipe aperture 410 when the casing parts are assembled. - The method for assembling the
safety system 700/700 a/700 b/700 c may include steps of: arranging, for each of thevalve units 200/200 d, the corresponding casing parts around at least the liquid control valve and the gas control valve of thevalve units 200/200 d; fixing, for each of thevalve units 200/200 d, the corresponding casing parts to each other; disposing, for each of thevalve units 200/200 d, therefrigerant leakage detector 500; arranging the connection structure so as to connect theinternal spaces 401 of thecasings 400; and connecting the discharge structure to the connection structure or one of thecasings 400. Thereby, thecasing 400 can be retrofitted to existing valves of a heat pump system. Theinsulators 450 may also be applied to the gap between the adjoining casing parts. - The
unit controller 600 of eachvalve unit 200 may have further functions. For instance, theunit controller 600 may be further configured to, when a refrigerant leakage in any of the utilization-side piping sections has occurred, control the liquid shut-offvalve 364 and the gas shut-off valve 365 (seeFIG. 2 ) defining the utilization-side piping section to close. Thereby, the utilization-side piping section can be zoned from other parts of the heat pump circuit. Alternatively, or in addition to this, when a refrigerant leakage has been detected in any one of thevalve units 200, theunit controller 600 may shut-down theair conditioning system 100 by, for instance, stopping the operation of the compressor in the heatsource-side unit and the operations of the utilization-side units 120. Thereby, it is possible to prevent as much as possible the refrigerant from leaking out further. - The position, the orientation, and the number of the
ventilator 730 are not limited to those according to the first to fourth embodiments. For instance, theventilator 730 may be arranged so as to blow air towards theinternal space 401 of thecasing 400 in which a refrigerant leakage has occurred. Thereby, it is also possible to discharge the air containing refrigerant from the correspondingfirst opening 420 with thedamper 440 open. In addition, an additional ventilator may be provided to theindividual duct 710, the connectingduct 740 a, and/or the sharedduct ventilator 730 and any one of theinternal spaces 401 to boost the suction force. - If refrigerant used is heavier than air and thus it is permissible to form the
first opening 420 in the upper part of thecasing 400, thedamper 440 for thefirst opening 420 is not necessarily required. If the isolation of theinternal space 401 of thecasing 400 is sufficient without anyspecific insulators 450,such insulators 450 may be omitted. - All or part of the
unit controller 600 may be separated from the correspondingvalve unit 200. In this case, thevalve unit 200 should have a communication interface such that theunit controller 600 can acquire the detection value Vs of therefrigerant leakage detector 500 and control the operation of the machineries of thevalve unit 200 including thedamper 440. - All or part of the
unit controllers 600 may be integrated to thecentral controller 800/800 a/800 b/800 c. For instance, thecentral controller 800/800 a/800 b/800 c may compare the detection values Vs with the detection value threshold Vth. Conversely, all or part of thecentral controller 800/800 a/800 b/800 c may be integrated to theunit controllers 600. For instance, each of theunit controller 600 may determine whether to open thedamper 440 of theown valve unit 200. - If the discharge of the internal air is performed continuously or regularly, under the control of the
unit controller 600 for instance, detection of the refrigerant leakage does not necessarily need to be performed, and thus therefrigerant leakage detector 500 is not required. In this case, the operations shown inFIGS. 4, 5, and 7 are not necessarily required. Moreover, if ventilation of the internal air via the connection structure is induced by natural convection or an air flow caused by an external mechanism, theventilator 730 is not necessarily required. - (Other Variations of Piping in Casing)
- As mentioned above, the piping accommodated in the
casing 400 is not limited to themulti branch selector 300. For instance, other elements which are potential refrigerant leakage points, such as the compressor of the heatsource-side unit 110, may be accommodated in thecasing 400. Thecasing 400 of the compressor may also be connected to the other casing orcasings 400 by the connection structure and provided with the discharge structure in the same manner as thecasings 400 of a plurality of themulti branch selectors 300 as explained above. - (Configuration of Air Conditioning System)
- As a fifth embodiment of the present invention, an air conditioning system is explained which can further improve safety regarding a refrigerant leakage from the compressor and its surrounding elements. In the fifth embodiment, a space surrounding a compressor unit is further subjected to the detection of refrigerant leakage and the discharge of air.
- The air conditioning system according to the fifth embodiment is similar to the
air conditioning system 100 according to the first embodiment. However, the configuration of the safety system is different from that of the first embodiment. The piping configuration may also be different from that of the first embodiment. These differences are explained hereinafter, and the other configurations not referred to are the same as the first embodiment unless otherwise indicated. The same reference signs as the first embodiment are appended to elements which are substantially the same as those of the first embodiment, and the explanations thereof are omitted. -
FIG. 13 is a schematic configuration diagram of an air conditioning system according to the fifth embodiment. - As shown in
FIG. 13 , theair conditioning system 100 h according to the fifth embodiment has the heatsource-side unit 110 h, thevalve unit 200 h, and the utilization-side units 120 which are connected by refrigerant pipes as with the first embodiment. Although being in the two-pipe configuration like the configuration shown inFIG. 12 , the heat pump system of theair conditioning system 100 h may have the three-pipe configuration like the configuration shown inFIG. 1 . In addition, although having thesingle valve unit 200 h, theair conditioning system 100 h may have two ormore valve units 200 h like the configuration shown inFIG. 1 . Meanwhile, as shown inFIG. 13 , the heatsource-side unit 110 h of the present embodiment is separated into two separate units of a HEX unit (a heat exchanger unit) 101 h and acompressor unit 111 h. - The
compressor unit 111 h has acompressor 112 h configured to compress first refrigerant. Thecompressor unit 111 h may further have aswitching mechanism 113 h configured to switch the state of the heat pump system between a cooling operation mode and a heating operation mode. In the cooling operation mode, a discharge port of thecompressor 112 h is connected to a piping leading to a later-mentioned outdoor heat exchanger, and a suction port of thecompressor 112 h is connected to a piping leading to later-mentioned indoor heat exchangers. In the heating operation mode, the discharge port of thecompressor 112 h is connected to the piping leading to the later-mentioned indoor heat exchangers, and the suction port of thecompressor 112 h is connected to the piping leading to the later-mentioned outdoor heat exchanger. Theswitching mechanism 113 h is a four-way valve for instance. Yet, theswitching mechanism 113 h may be omitted if only either one of the cooling operation mode and the heating operation mode needs to be performed. - The
HEX unit 101 h has an outdoor heat exchanger 102 h which is configured to allow air to pass therethrough and allow the first refrigerant to flow therein to exchange heat between the air and the first refrigerant. The outdoor heat exchanger 102 h is connected to one of the discharge port and the suction port of thecompressor 112 h via part of thegas refrigerant pipe 132. The outdoor heat exchanger 102 h is also connected to the later-mentioned indoor heat exchangers via the liquidrefrigerant pipe 131, the heatsource-sideliquid pipe portion 310 and the utilization-sideliquid pipe portions 311 of thevalve unit 200 h, and the utilization-side liquidrefrigerant pipe 151. The outdoor heat exchanger 102 h may be provided with a fan to facilitate flow of the air. - Each of the utilization-
side unit 120 has anindoor heat exchanger 122 h which corresponds to the utilization-side heat exchanger mentioned in the first embodiment. Each of theindoor heat exchangers 122 h is connected to the outdoor heat exchanger 102 h via the above-mentioned piping, and configured to allow air to pass therethrough and allow the first refrigerant to flow therein to exchange heat between the air and the first refrigerant. Each of theindoor heat exchangers 122 h is further connected to the other one the discharge port and the suction port of thecompressor 112 h via the utilization-sidegas refrigerant pipe 152, the utilization-sidegas pipe portion 330 and the low-pressuregas pipe portion 320 of thevalve unit 200 h, and another part of thegas refrigerant pipe 132. Each of theindoor heat exchangers 122 h may be provided with a fan to facilitate flow of the air. - The
air conditioning system 100 h further has expansion mechanisms (not shown), such as electric expansion valves, for decompressing and expanding the first refrigerant flowing between the outdoor heat exchanger 102 h and theindoor heat exchangers 122 h. Theair conditioning system 100 h may further has an accumulator (not shown) disposed in thegas refrigerant pipe 132 at a point close to the suction port of thecompressor 112 h for accumulating excess refrigerant and separating gas refrigerant from the first refrigerant. Theair conditioning system 100 h may further has sensors (not shown) for detecting temperature and/or pressure of refrigerant which are necessary for controlling the operation of theair conditioning system 100 h. - Thus, the
air conditioning system 100 h has first connection pipes connecting theHEX unit 101 h and thecompressor unit 111 h such that the first refrigerant circulates therebetween, and second connection pipes connecting thecompressor unit 111 h, thevalve unit 200 h, and the utilization-side units 120 such that the first refrigerant circulates between thecompressor unit 111 h and the utilization-side units 120 via thevalve unit 200 h. In other words, theHEX unit 101 h, thecompressor unit 111 h, thevalve unit 200 h, and each of the utilization-side units 120 are connected via refrigerant pipes so as to form a heat pump circuit using the first refrigerant. - Here, the “first refrigerant” may be CO2 refrigerant (carbon oxide refrigerant), R290 refrigerant (propane), HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf, but is not limited to these refrigerants.
- In this embodiment, the
HEX unit 101 h is installed in afirst space 931 h which is an outdoor space or a space through which outdoor air is allowed to pass. Thereby, the outdoor heat exchanger 102 h can be continuously supplied with drafts of outdoor air to effectively release heat from or absorb heat into the first refrigerant. The utilization-side units 120 are installed in atarget space 933 h which is to be air conditioned. Thereby, theindoor heat exchangers 122 h can perform a heat exchange between the first refrigerant and air in thetarget space 933 h to cool or warm it. Yet, the utilization-side units 120 need not necessarily be installed in thetarget space 933 h. If an outlet port of each of the utilization-side units 120 for supplying air-conditioned air leads to thetarget space 933 h via a duct or the like, the utilization-side units 120 may be disposed outside thetarget space 933 h. - Meanwhile, the
compressor unit 111 h and thevalve unit 200 h are installed in asecond space 932 h which is different from any of thefirst space 931 h and the target space 933. As detailed later, it is preferable that thesecond space 932 h is substantially isolated in normal times from at least thefirst space 931 h and thetarget space 933 h, and ventilation of thesecond space 932 h is controlled independently from that of thefirst space 931 h and thetarget space 933 h. - For instance, the target space 933 is a room of a building to which the
air conditioning system 100 h is installed such as an office room. Thus, the utilization-side units 120 are so-called indoor units. Thefirst space 931 h is a room of the same building which has an air passage or passages freely leading to the outdoor space, or an outdoor space outside the building such as a space of a roof floor of the building. Thesecond space 932 h is another room of the same building such as a machine room, a computer room, or a warehouse. - (Configuration of Safety System)
- The safety system of the present embodiment includes a ventilation control structure for controlling the ventilation environment of the
second space 932 h. In this embodiment, a configuration is explained in which the ventilation control structure causes a forced ventilation of thesecond space 932 h when a refrigerant leakage has occurred in thesecond space 932 h. More specifically, the ventilation control structure includes a discharge structure that operates to discharge air from thesecond space 932 h when concentration of the first refrigerant in thesecond space 932 h has increased. -
FIG. 14 is a schematic configuration diagram of the safety system of theair conditioning system 100 h. - As shown in
FIG. 14 , thesecond space 932 h is defined as a room by abuilding structure 934 h. In other words, the internal space of thebuilding structure 934 h is thesecond space 932 h. Thisbuilding structure 934 h may also be regarded as part of the ventilation control structure. - For instance, the
building structure 934 h includes a floor, a ceiling facing the floor, and at least one wall which connects the floor and the ceiling and surrounds a space between the floor and a ceiling. Thebuilding structure 934 h may further include a door arranged in the floor, the ceiling, or the wall. Thebuilding structure 934 h is formed with afirst airflow passage 935 h and asecond airflow passage 936 h between thesecond space 932 h and an outer space outside of thesecond space 932 h. This outer space is preferably the outdoor space. - The
safety system 700 h includes a refrigerant leakage detector (a first leakage detector) 500 disposed in thesecond space 932 h, and a discharge structure. The discharge structure includes adamper 440 disposed to thefirst airflow passage 935 h, aventilator 730 disposed to thesecond airflow passage 936 h, and acentral controller 800 h. Here, any of therefrigerant leakage detector 500 and thecentral controller 800 h may be part of thecompressor unit 111 h or thevalve unit 200 h. The configurations of theventilator 730, thedamper 440, and therefrigerant leakage detector 500 may be the same as those of the first to fourth embodiments. As with these embodiments, theventilator 730, thedamper 440, and therefrigerant leakage detector 500 are connected to thecentral controller 800 h via acommunication path 801 by means of a wired and/or wireless communication. - The
refrigerant leakage detector 500 is configured to detect at least a concentration of the first refrigerant in air. Theventilator 730 is configured to draw air from thesecond space 932 h towards an external space which is different from any of thetarget space 933 h and thesecond space 932 h via thesecond airflow passage 936 h. Thedamper 440 may be a check air damper, and configured to keep thefirst airflow passage 935 h closed in normal times. Yet, under the control of thecentral controller 800 h as mentioned later, thedamper 440 is configured to open thefirst airflow passage 935 h when theventilator 730 is in operation. Thus, thefirst airflow passage 935 h works as an intake port of an external air for promoting the ventilation of thesecond space 932 h. - It is noted that any of the
first airflow passage 935 h and thesecond airflow passage 936 h may be an opening formed in thebuilding structure 934 h, or a duct, a pipe, or the like which is connected to such an opening. Thus, theventilator 730 and/or thedamper 440 may be disposed to thebuilding structure 934 h, inside thesecond space 932 h, or outside thesecond space 932 h. Such an opening may be formed in any part of thebuilding structure 934 h, such as the wall, the ceiling, the floor, the door, and the window. For instance, each of thefirst airflow passage 935 h and thesecond airflow passage 936 h is formed in an exterior wall of the building which also defines thesecond space 932 h. In any cases, it is preferable that thebuilding structure 934 h is configured such that its internal space (i.e.second space 932 h) is substantially closed in the normal times. - The
central controller 800 h is configured to, when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold (e.g. when the detected concentration has reached to the first detection value threshold), control theventilator 730 to operate, and also control thedamper 440 to open. - (Operation of Central Controller)
- The
central controller 800 h corresponds to thecentral controller 800 of the first embodiment and may have the same hardware configuration as thecentral controller 800. Thecentral controller 800 h performs an operation similar to the operations by theunit controller 600 and thecentral controller 800 of the first embodiment. Yet, in the present embodiment, the operation is made simpler. -
FIG. 15 is a flow chart indicating the operation performed by thecentral controller 800 h. In the flow chart, steps S3010 h, S3020 h, S3030 h, S3040 h, and S3050 h correspond to steps S1010, S1020, S2040, S1120, S1110 explained in the first embodiment, respectively. - In step S3010 h, the
central controller 800 h acquires the detection value as a first detection value Vs1 from the detector signal outputted from therefrigerant leakage detector 500. Thecentral controller 800 h may passively receive the detector signal which is continuously or regularly outputted from therefrigerant leakage detector 500, or actively request therefrigerant leakage detector 500 to output the detector signal regularly. - In step S3020 h, the
central controller 800 h compares the first detection value Vs1 acquired and the first detection value threshold Vth1, and determines whether the first detection value Vs1 is less than the first detection value threshold Vth1. Thecentral controller 800 h may obtain a moving average value of the detection values Vs1 in a certain time length to use the moving average value as the first detection value Vs1 which is compared with the first detection value threshold Vth1. - The first detection value threshold Vth1 is stored in the
central controller 800 h in advance. The first detection value threshold Vth1 may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the first detection value threshold Vth1 is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the refrigerant used. - If the first detection value Vs1 is equal to or greater than the first detection value threshold Vth1 (S3020 h: No), the
central controller 800 h proceeds to later-mentioned step S3030 h. If the first detection value Vs1 is less than the first detection value threshold Vth1 (S3020 h: Yes), thecentral controller 800 h proceeds to later-mentioned step S3050 h. - In step S3030 h, the
central controller 800 h transmits a ventilator start command to theventilator 730 to control theventilator 730 to start operating. Thecentral controller 800 h may control the operation of theventilator 730 by controlling a supply of electricity thereto. - In step S3040 h, the
central controller 800 h controls thedamper 440 to open. For instance, thecentral controller 800 h controls the state of thedamper 440 by controlling a supply of electricity thereto. Thecentral controller 800 h may output alarm information by means of a sound, a light, a visual image, and/or a communication signal from a loudspeaker, an electric light, a display device, and/or a communication interface provided to thecentral controller 800 h. - The execution order of step S3030 h and step S3040 h may be reversed. Moreover, the
damper 440 and theventilator 730 need not necessarily be controlled directly by thecentral controller 800 h. Thedamper 440 may be controlled via theventilator 730, or theventilator 730 may be controlled via thedamper 440. - In step S3050 h, the
central controller 800 h determines whether termination of operation has been designated. The designation may be made by a user operation, another device, or thecentral controller 800 h itself. If termination of the operation has not been designated (S3050 h: No), thecentral controller 800 h goes back to step S3010 h to repeat the above acquisition and determination steps. If termination of the operation has been designated (S3050 h: Yes), thecentral controller 800 h terminates its operation regarding the safety system. - By this operation, when the refrigerant leakage has occurred in any of the
compressor unit 111 h and thevalve unit 200 h, the state of thesecond space 932 h can be switched from a normal state (a first state) to an emergency state (a second state) in which a ventilation of thesecond space 932 h is promoted more than in the normal state. - (Advantageous Effect of Fifth Embodiment)
- According to the fifth embodiment mentioned above, differently from the
first space 931 h which requires a continuous supply of outdoor air, the ventilation of thesecond space 932 h can be restricted in normal times. Thereby, when a refrigerant leakage in any of thecompressor unit 111 h and thevalve unit 200 h has occurred, it is possible to swiftly detect it by therefrigerant leakage detector 500. Then, when the occurrence of refrigerant leakage has been detected, the ventilation of thesecond space 932 h is started. Hence, the air containing the leaked refrigerant can be discharged from thesecond space 932 h at an early stage. Accordingly, it is possible to improve safety regarding refrigerant leakage at low cost, even in a case where thecompressor 112 h should be arranged inside the building. - Any of the
compressor unit 111 h and thevalve unit 200 h need not necessarily have a casing like thecasings 400 according to the first to fourth embodiments. Yet, it is also possible to apply the safety systems including thecasings 400 of any of the first to fourth embodiments to thecompressor unit 111 h and thevalve unit 200 h of the present embodiment. As variations of the first embodiment, the cases are explained below where thecompressor unit 111 h and thevalve unit 200 h are covered by one or more casings. - (First Variation of Fifth Embodiment)
- In the same manner as the second embodiment (see
FIG. 16 ) for twovalve units 200, thecompressor unit 111 h and thevalve unit 200 h may be covered by two casings which are connected in series by the connection structure and provided with the discharge structure. -
FIG. 16 is a schematic configuration diagram of a safety system according to a first variation of the fifth embodiment. - As shown in
FIG. 16 , asafety system 700 i according to the first variation comprises a compressor unit casing 400_c (a first casing) and a valve unit casing 400_v (a second casing) which are arranged within thesecond space 932 h as part of thesecond space 932 h. The compressor unit casing 400_c accommodates at least part of thecompressor unit 111 h. This accommodated part includes at least thecompressor 112 h. The valve unit casing 400_v accommodates at least part of thevalve unit 200 h. This accommodated part includes at least the liquid shut-offvalves 364 and the gas shut-offvalves 365. The compressor unit casing 400_c may be regarded as part of thecompressor unit 111 h, and the valve unit casing 400_v may be regarded as part of thevalve unit 200 h. - The compressor unit casing 400_c and the valve unit casing 400_v correspond to the
casings 400 according to the second embodiment, and may have the same configurations thereof. The compressor unit casing 400_c is formed with a first opening 420_c and a second opening 430_c, and the valve unit casing 400_v is formed with a first opening 420_v and a second opening 430_v. - The
safety system 700 i has a serial structure similar to the second embodiment. Thesafety system 700 i has a connecting duct 740 which is connected on one side to the second opening 430_c of compressor unit casing 400_c, and connected on another side to the first opening 420_v of the valve unit casing 400_v. Thus, the connecting duct 740 is a connection structure connecting an internal space 401_c of the compressor unit casing 400_c and an internal space 401_v of the valve unit casing 400 v. - The
safety system 700 i further has anintake duct 750 i which is connected on one side to thefirst airflow passage 935 h, and connected on another side to the first opening 420_c of the compressor unit casing 400_c. Thus, theintake duct 750 i connects the outer space of thesecond space 932 h and the internal space 401_c of the compressor unit casing 400_c. Here, thefirst airflow passage 935 h may be regarded as part of theintake duct 750 i, or theintake duct 750 i may be regarded as part of thefirst airflow passage 935 h. - The
safety system 700 i further has a sharedduct 720 a which is connected on one side to the second opening 430_v of the valve unit casing 400_v, and connected on another side to thesecond airflow passage 936 h. Thus, the sharedduct 720 a is a discharge duct connecting the outer space of thesecond space 932 h and the internal space 401_v of the valve unit casing 400_v. Here, thesecond airflow passage 936 h may be regarded as part of the sharedduct 720 a, and the sharedduct 720 a may be regarded as part of thesecond airflow passage 936 h. - The
safety system 700 i also has aventilator 730 disposed to the sharedduct 720 a. The configurations of these may be the same as those of the sharedduct 720 a and theventilator 730 according to the second embodiment. As already mentioned, any of thefirst airflow passage 935 h and thesecond airflow passage 936 h may be an opening of thebuilding structure 934 h or a duct connected to such an opening. Thus, theventilator 730 and/or thedamper 440 may be mounted to thebuilding structure 934 h, arranged inside thesecond space 932 h, or arranged outside thesecond space 932 h. - Hence, as with the second embodiment, the compressor unit casing 400_c and the valve unit casing 400_v are connected by the connecting duct 740 in series with respect to the shared
duct 720. Yet, differently from the second embodiment, thedamper 440 disposed between the compressor unit casing 400_c and the valve unit casing 400_v is omitted. It is noted that the positions of the casing 400_c, 400_v with respect to theintake duct 750 i and the sharedduct 720 a may be reversed. - The
safety system 700 i further has a compressor unit leakage detector 500_c which corresponds to therefrigerant leakage detector 500 according to the second embodiment. The compressor unit leakage detector 500_c is disposed in the internal space 401_c of the compressor unit casing 400_c, and may be part of thecompressor unit 111 h. The compressor unit leakage detector 500_c is configured to detect at least a concentration of the first refrigerant in air. - The
safety system 700 i further has acentral controller 800 i which corresponds to theunit controller 600 and thecentral controller 800 a according to the second embodiment, and may have the same hardware configuration as theunit controller 600 and/or thecentral controller 800 a. Thecentral controller 800 i may be part of thecompressor unit 111 h. Thecentral controller 800 i may perform the operation as shown inFIG. 15 based on the detector signal outputted from the compressor unit leakage detector 500_c. - Additionally, as shown in
FIG. 16 , thesafety system 700 i may further have a valve unit leakage detector 500_v disposed in the internal space 401_c of the valve unit casing 400_v, which may have the same configuration as the compressor unit leakage detector 500_c. In this case, it is preferable that thecentral controller 800 i further performs the determination of step S3020 h based on the detector signal outputted from the valve unit leakage detector 500_v. In other words, thecentral controller 800 i starts theventilator 730 and open thedamper 440 when a refrigerant leakage has occurred in any of the compressor unit casing 400_c and the valve unit casing 400_v. The detector signal of the valve unit leakage detector 500_v may be relayed to thecentral controller 800 i by theunit controller 600 of thevalve unit 200 h via thecommunication path 801, or directly transmitted to thecentral controller 800 i via thecommunication path 801. - The total volume of the internal spaces 401_c, 401_v of the casings 400_c, 400_v and internal spaces of the
ducts damper 440 and theventilator 730 can be made much smaller than the volume of the wholesecond space 932 h. Thus, both the detection of the refrigerant leakage and the discharge of the air containing the leaked refrigerant can be performed more swiftly compared with the configuration shown inFIG. 14 . Moreover, the casings 400_c, 400_v andducts compressor unit 111 h or thevalve unit 200 h from spreading in thesecond space 932 h. Hence, the safety regarding refrigerant leakage can be further improved. - It is noted that the internal space 401_c of the compressor unit casing 400_c and the internal space 401_v of the valve unit casing 400_v are part of the
second space 932 h but can also be regarded as a second space in which thecompressor unit 111 h, thevalve unit 200 h, and the compressor unit leakage detector 500_c are installed and which is different from any of thetarget space 933 h and thefirst space 931 h. In this case, since the internal spaces 401_c, 401_v are substantially closed in normal times, thebuilding structure 934 h need not necessarily be configured to close its internal space (i.e.second space 932 h). - (Second Variation of Fifth Embodiment)
- Instead of being connected in series, the casings 400_c, 400_v may be connected in parallel with respect to the shared duct.
-
FIG. 17 is a schematic configuration diagram of a safety system of an air conditioning system according to a second variation of the fifth embodiment. - The
safety system 700 j according to the second variation has the same configuration as thesafety system 700 i of the first variation except for the structure for connecting the internal spaces 401_c, 401_v of the casings 400_c, 400_v to the external space or spaces of thesecond space 932 h. In other words, the casings 400_c, 400_v of thecompressor unit 111 h and thevalve unit 200 h are connected in the same manner as thecasings 400 of thevalve units 200 according to the first embodiment as shown inFIG. 3 . - As shown
FIG. 17 , thesafety system 700 j has a first intake duct 750 i_c which corresponds to theintake duct 750 i according to the first variation. Yet, instead of the connectingduct 740 a and the sharedduct 720 a of the first variation, thesafety system 700 j has a second intake duct 750 i_v, a first individual duct 710_1, a second individual duct 710_2, and a sharedduct 720 b. - The
building structure 934 h is further formed with athird airflow passage 937 j between thesecond space 932 h and an outer space outside of thesecond space 932 h. The second intake duct 750 i_v is connected on one side to thisthird airflow passage 937 j, and connected on another side to the first opening 420_v of the valve unit casing 400_v. In other words, the second intake duct 750 i_v connects the outer space of thesecond space 932 h and the internal space 401_v of the valve unit casing 400_v. Here, thethird airflow passage 937 j may be regarded as part of the second intake duct 750 i_v, and the second intake duct 750 i_v may be regarded as part of thethird airflow passage 937 j. - The configurations and/or arrangements of the
third airflow passage 937 j and the second intake duct 750 i_v may be the same as or similar to those of thefirst airflow passage 935 h and the first intake duct 750 i_c. Adamper 440 is also disposed to thethird airflow passage 937 j as with thefirst airflow passage 935 h. Thethird airflow passage 937 j may be an opening of thebuilding structure 934 h or a duct connected to such an opening as with thefirst airflow passage 935 h and thesecond airflow passage 936 h. Thus, thedampers 440 disposed to thethird airflow passage 937 j may also be mounted to thebuilding structure 934 h, arranged inside thesecond space 932 h, or arranged outside thesecond space 932 h. - The first individual duct 710_1 connects the second opening 430_v of the valve unit casing 400_v to the shared
duct 720 b. The second individual duct 710_2 connects the second opening 430_c of the compressor unit casing 400_c to the sharedduct 720 b. Thus, the first and second individual ducts 710_1, 710_2 form a connection structure connecting the internal spaces 401_c, 401_v of the casings 400_c, 400_v, and the sharedduct 720 b connects this connection structure and the external space of thesecond space 932 h. Theventilator 730 is disposed to the sharedduct 720 b at or close to one end of the sharedduct 720 b, and configured to draw air in the sharedduct 720 b towards the second end. The configurations of these elements may be the same as those of theindividual ducts 710, the sharedduct 720 b, and theventilator 730 according to the first embodiment. - The central 800 i may perform the operation as shown in
FIG. 15 , while controlling both thedampers 440 to open in step S3040 h upon controlling theventilator 730 to start operating. - With the second variation as explained above, each of the internal spaces 401_c, 401_v communicates with the discharge structure without being interposed by any other casing. Hence, it is possible to reduce static pressure capacity required of the
ventilator 730. This would further reduce the installation cost of the air conditioning system. It is noted that thefirst airflow passage 935 h and thethird airflow passage 937 j may be integrated to a single airflow passage. In this case, thedampers 440 for them may also be integrated a single damper. - (Third Variation of Fifth Embodiment)
- Instead of being covered by respective casings, the
compressor unit 111 h and thevalve unit 200 h may be covered by a single casing. -
FIG. 18 is a schematic configuration diagram of a safety system of an air conditioning system according to a third variation of a fifth embodiment. - The
safety system 700 k according to the third variation has the same configuration as thesafety system 700 i of the first variation except for the structure for coveringcompressor unit 111 h and thevalve unit 200 h. As shown inFIG. 18 , thesafety system 700 k has acasing 400 arranged within thesecond space 932 h, instead of the casings 400_c, 400_v and the connectingduct 740 a of the first variation, as part of thesecond space 932 h. Thecasing 400 accommodates at least part of thecompressor unit 111 h and at least part of thevalve unit 200 h. These accommodated parts include at least thecompressor 112 h, the liquid shut-offvalves 364, and the gas shut-offvalves 365. Thecasing 400 corresponds to eachcasing 400 according to the second embodiment, and may have the same configuration thereof. - The
safety system 700 k also has arefrigerant leakage detector 500 and acentral controller 800 i which correspond to the compressor unit leakage detector 500_c and thecentral controller 800 i according to the first variation, respectively. Therefrigerant leakage detector 500 is disposed in aninternal space 401 of thecasing 400. Thecentral controller 800 i may perform the operation as shown inFIG. 15 based on the detector signal outputted from therefrigerant leakage detector 500. - It is noted that the
internal space 401 of thecasing 400 is part of thesecond space 932 h but can also be regarded as a second space in which thecompressor unit 111 h, thevalve unit 200 h, and therefrigerant leakage detector 500 are installed and which is different from any of thetarget space 933 h and thefirst space 931 h. In this case, since theinternal space 401 is substantially closed in normal times, thebuilding structure 934 h need not necessarily be configured to close its internal space (i.e.second space 932 h). - This third variation is suitable for the case where the
compressor unit 111 h and thevalve unit 200 h are arranged close to each other. With this variation, since the number of thecasing 400 is decreased and the connectingduct 740 a is not required, it is possible to further reduce the installation cost of the air conditioning system. - (Configuration of Air Conditioning System)
- In the above fifth embodiment, the air conditioning system is configured such that the same refrigerant flows through the HEX unit, the compressor unit, the valve unit, and the utilization units. Yet, the configurations of the safety systems (the ventilation control structures) according to the fifth embodiment and its variations may also be applied to other types of piping. For instance, the safety system can be applied to an air conditioning system of a cascade-type in which two or more circuits of the same or different heat mediums are formed and a heat exchange therebetween is performed. As a sixth embodiment of the present invention, an air conditioning system of a cascade-type is explained.
- The air conditioning system according to the sixth embodiment is similar to the
air conditioning system 100 h according to the fifth embodiment. Yet, the configuration of the piping is different from that of the fifth embodiment. This difference is explained hereinafter, and the other configurations not referred to are the same as the fifth embodiment unless otherwise indicated. The same reference signs as the fifth embodiment are appended to elements which are substantially the same as those of the fifth embodiment, and the explanations thereof are omitted. -
FIG. 19 is a schematic configuration diagram of the air conditioning system according to the sixth embodiment. - As shown in
FIG. 19 , the piping of theair conditioning system 100 m according to the sixth embodiment is separated into afirst circuit 105 m for first refrigerant and asecond circuit 106 m for second refrigerant. Theair conditioning system 100 m has aHEX unit 101 m, acompressor unit 111 m, avalve unit 200 m, and utilization-side units 120 m which correspond to theHEX unit 101 h, thecompressor unit 111 h, thevalve unit 200 h, and the utilization-side units 120 according to the fifth embodiment, respectively. - The
HEX unit 101 m includes anoutdoor heat exchanger 102 m corresponding to the outdoor heat exchanger 102 h of the fifth embodiment, and thecompressor unit 111 m includes acompressor 112 m and aswitching mechanism 113 m corresponding to thecompressor 112 h and theswitching mechanism 113 h of the fifth embodiment. Yet, thecompressor unit 111 m according to the present embodiment further has arefrigerant heat exchanger 114 m. TheHEX unit 101 m and thecompressor unit 111 m are connected by a unit liquidrefrigerant pipe 103 m and a unitgas refrigerant pipe 104 m (first connection pipes) such that the first refrigerant circulates therebetween. - The
refrigerant heat exchanger 114 m is configured to allow each of the first refrigerant and the second refrigerant to flow therein so as to exchange heat between the first refrigerant and the second refrigerant. - Hence, the
compressor 112 m, the switching mechanism 113, the outdoor heat exchanger 102 h, therefrigerant heat exchanger 114 m, and the pipes connecting them form thefirst circuit 105 m which circulates the first refrigerant. - The
valve unit 200 m includes a heatsource-sideliquid pipe portion 310 m, a low-pressuregas pipe portion 320 m, utilization-sideliquid pipe portions 311 m, utilization-sidegas pipe portions 330 m, liquid shut-offvalves 364 m, and gas shut-offvalves 365 m which correspond to the heatsource-sideliquid pipe portion 310, the low-pressuregas pipe portion 320, the utilization-sideliquid pipe portions 311, the utilization-sidegas pipe portions 330, the liquid shut-offvalves 364, and the gas shut-offvalves 365 according to the fifth embodiment, respectively. Each of the utilization-side units 120 m includes anindoor heat exchanger 122 m corresponding to the indoor heat exchanger 122 according to the fifth embodiment. Thecompressor unit 111 m, thevalve unit 200 m, and the utilization-side units 120 m are connected to each other via a liquidrefrigerant pipe 131 m, agas refrigerant pipe 132 m, utilization-side liquidrefrigerant pipes 151 m, and utilization-sidegas refrigerant pipes 152 m corresponding to the liquidrefrigerant pipe 131, thegas refrigerant pipe 132, the utilization-side liquidrefrigerant pipes 151, and the utilization-sidegas refrigerant pipes 152 according to the fifth embodiment. - Yet, differently from the fifth embodiment, these elements of the
valve unit 200 m and the utilization-side units 120 m and therefrigerant pipes - The liquid
refrigerant pipe 131 m and thegas refrigerant pipe 132 m (second connection pipes) are connected to therefrigerant heat exchanger 114 m of thecompressor unit 111 m such that the second refrigerant circulates between thecompressor unit 111 m and the utilization-side units 120 m via thevalve unit 200 m. Theair conditioning system 100 m further has apump 116 m disposed to the liquidrefrigerant pipe 131 m or thegas refrigerant pipe 132 m, preferably as part of thecompressor unit 111 m. Thepump 116 m is configured to induce a flow of the second refrigerant. Hence, thepump 116 m, theindoor heat exchangers 122 m, therefrigerant heat exchanger 114 m, and the pipes connecting them form thesecond circuit 106 m which circulates the second refrigerant. Thepump 116 m may be a compressor for compressing the second refrigerant. In this case, elements required for forming a heat pump circuit such as an expansion mechanism and an accumulator may also be provided to thesecond circuit 106 m. - Here, the refrigerant type of the second refrigerant is the same as or different from that of the first refrigerant. The “second refrigerant” may be CO2 refrigerant (carbon oxide refrigerant), R290 refrigerant (propane), HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf, but is not limited to these refrigerants. For instance, HFC or HFC refrigerant is used as the first refrigerant, and CO2 refrigerant is used as the second refrigerant.
- The
HEX unit 101 m is installed in thefirst space 931 h, thecompressor unit 111 m and thevalve unit 200 m are installed in thesecond space 932 h, and the utilization-side units 120 are installed in thetarget space 933 h. Any of thesafety systems 700h air conditioning system 100 m. Nevertheless, in a case where the refrigerant type of the second refrigerant is different from that of the first refrigerant, it is preferable to use a refrigerant leakage detector for the second refrigerant in addition to therefrigerant leakage detector 500 for the first refrigerant. -
FIG. 20 is a schematic configuration diagram of an example of a safety system of theair conditioning system 100 m. - As shown in
FIG. 20 , asafety system 700 m of theair conditioning system 100 m may have substantially the same configuration as thesafety system 700 h of the fifth embodiment. Yet, instead of therefrigerant leakage detector 500 and thecentral controller 800 h of the fifth embodiment, thesafety system 700 m has afirst leakage detector 501 m, asecond leakage detector 502 m, and acentral controller 800 m. Thefirst leakage detector 501 m may be the same as the refrigerant leakage detectors 500_c according to the first variation of the fifth embodiment. Thecompressor unit 111 m and thevalve unit 200 m may be covered by respective casings or a single casing. If thecompressor unit 111 m has a casing accommodating at least thecompressor 112 m, thefirst leakage detector 501 m may be disposed in the casing like the first variation of the fifth embodiment. - Meanwhile, the
second leakage detector 502 m is disposed in thesecond space 932 h but outside any casings of thecompressor unit 111 m and thevalve unit 200 m for instance. Thesecond leakage detector 502 m is configured to detect at least a concentration of the second refrigerant in an air surrounding thesecond leakage detector 502 m, and continuously or regularly output a detector signal indicating a detection value Vs2 to thecentral controller 800 m via thecommunication path 801. Thesecond leakage detector 502 m may be a semi-conductor gas sensor reactive to the second refrigerant. In a case where the second refrigerant is heavier than atmospheric air, such as CO2 refrigerant, thesecond leakage detector 502 m is preferably disposed in thesecond space 932 h at or close to an inner bottom surface of thesecond space 932 h. - The
central controller 800 m corresponds to thecentral controller 800 i of the first variation of the fifth embodiment, and may have the same hardware configuration as thecentral controller 800 i. Yet, thecentral controller 800 m according to the present embodiment further controls theventilator 730 to start operating when the detected concentration of the second refrigerant has been increased. -
FIG. 21 is a flow chart indicating an operation performed by thecentral controller 800 m. - As shown in
FIG. 21 , thecentral controller 800 m performs all steps S3010 h, S3020 h, S3030 h, S3040 h, and S3050 h according to the fifth embodiment shown inFIG. 15 as with thecentral controller 800 i of the first variation of the fifth embodiment. Thecentral controller 800 m further performs operations of steps S3021 m, S3022 m before step S3010 h or between step S3020 h and step S3050 h. - In step S3021 m, the
central controller 800 m acquires the detection value as a second detection value Vs2 from the detector signal outputted from thesecond leakage detector 502 m. Thecentral controller 800 m may passively receive the detector signal which is continuously or regularly outputted from thesecond leakage detector 502 m, or actively request thesecond leakage detector 502 m to output the detector signal regularly. The obtained first detection value Vs2 basically reflects the variation in the concentration of the second refrigerant in thesecond space 932 h. - In step S3022 m, the
central controller 800 m compares the second detection value Vs2 acquired and a second detection value threshold Vth2, and determines whether the second detection value Vs2 is less than the second detection value threshold Vth2. Thecentral controller 800 m may obtain a moving average value of the detection values Vs2 in a certain time length to use the moving average value as the second detection value Vs2 which is compared with the second detection value threshold Vth2. - The second detection value threshold Vth2 is stored in the
central controller 800 m in advance. The second detection value threshold Vth2 may be a value determined by experiments or the like such that false detections and detection omissions of refrigerant leakages are avoided as much as possible. It is preferable that the second detection value threshold Vth2 is set to a value less than a value corresponding to 25% of the Lower Flammability Limit (LFL) of the second refrigerant. Also, in case of using a toxic refrigerant such as CO2 refrigerant, as the second refrigerant, it is preferable that the second detection value threshold Vth2 is set to a value less than a value corresponding to the toxicity limit. In case of CO2 refrigerant, the value of the toxicity limit is 0.1 kg/m3. The second detection value threshold Vth2 may be the same as or different from the first detection value threshold Vth1. - If the second detection value Vs2 is equal to or greater than the second detection value threshold Vth2 (S3022 m: No), the
central controller 800 m proceeds to step S3030 h. If the second detection value Vs2 is less than the second detection value threshold Vth2 (3022 m: Yes), thecentral controller 800 m proceeds to step S3050 h. - With the above configuration, when the refrigerant leakage has occurred in any of the
compressor unit 111 m and thevalve unit 200 m, the ventilation of thesecond space 932 h can be swiftly performed. Moreover, thesecond leakage detector 502 m is disposed outside any casings of thecompressor unit 111 m and thevalve unit 200 m. Thus, even a refrigerant leakage from pipe portions outside the casing or casings covering thecompressor unit 111 m and/or thevalve unit 200 m, such as the utilization-side liquidrefrigerant pipes 151 m or utilization-sidegas refrigerant pipes 152 m (in particular the connection parts of the pipes), can be detected. Hence, it is possible to effectively improve the safety of the air conditioning system of a cascade-type regarding refrigerant leakage. - However, the positions of the first and
second leakage detectors second leakage detector 502 m may be disposed in a casing of thevalve unit 200 m. - The
safety system 700 m explained above is preferred for the cascade-type system where HFC refrigerant such as R32 and R410A, or HFO refrigerant such as R-1234ze and R-1234yf is used as the first refrigerant, and C02 refrigerant (carbon oxide refrigerant) as the second refrigerant, for instance. - (Configuration of Air Conditioning System)
- In the above fifth and sixth embodiments, the air conditioning systems are of an air-cooling type in which the first refrigerant is subjected to heat exchange with outdoor air. Yet, the safety systems explained in the fifth and sixth embodiments can also be applied to any other types including a water-cooling type in which the first refrigerant is subjected to heat exchange with coolant water or brine. As a seventh embodiment of the present invention, an air conditioning system of a water-cooling type is explained.
- The air conditioning system according to the seventh embodiment is similar to the
air conditioning system 100 according to the fifth embodiment. However, the configuration of the piping is different from that of the fifth embodiment. This difference is explained hereinafter, and the other configurations not referred to are the same as the fifth embodiment unless otherwise indicated. The same reference signs as the fifth embodiment are appended to elements which are substantially the same as those of the fifth embodiment, and the explanations thereof are omitted. -
FIG. 22 is a schematic configuration diagram of the air conditioning system according to the seventh embodiment. - As shown in
FIG. 22 , the piping of theair conditioning system 100 n according to the seventh embodiment is separated into afirst circuit 105 n for heat medium and asecond circuit 106 n for first refrigerant. The heat medium may be coolant water or brine. Theair conditioning system 100 n has aHEX unit 101 n, acompressor unit 111 n, avalve unit 200 h, and utilization-side units 120 which correspond to theHEX unit 101 h, thecompressor unit 111 h, thevalve unit 200 h, and the utilization-side units 120 according to the fifth embodiment, respectively. - The
HEX unit 101 n includes anoutdoor heat exchanger 102 n corresponding to the outdoor heat exchanger 102 h of the fifth embodiment, and thecompressor unit 111 n includes a compressor 112 n corresponding to thecompressor 112 h of the fifth embodiment. Yet, thecompressor unit 111 n does not include theswitching mechanism 113 h, but includes a heat medium-refrigerant heat exchanger 117 n. TheHEX unit 101 n and thecompressor unit 111 n are connected by asupply pipe 107 n and areturn pipe 108 n (first connection pipes) such that the heat medium circulates therebetween. TheHEX unit 101 n may be a closed type cooling tower which cools the heat medium flowing in theoutdoor heat exchanger 102 n by supplying air while sprinkling water, but is not limited to this. - The heat medium-
refrigerant heat exchanger 117 n is configured to allow each of the heat medium and the first refrigerant to flow therein so as to exchange heat between the heat medium and the first refrigerant. The heat medium-refrigerant heat exchanger 117 n is connected to theoutdoor heat exchanger 102 n via thesupply pipe 107 n and thereturn pipe 108 n. Theair conditioning system 100 n further has apump 118 n disposed to thesupply pipe 107 n or thereturn pipe 108 n, preferably as part of thecompressor unit 111 n. Thepump 118 n is configured to induce a flow of the heat medium. - Hence, the
outdoor heat exchanger 102 n, thepump 118 n, the heat medium-refrigerant heat exchanger 117 n, and the pipes connecting them form thefirst circuit 105 n which circulates the heat medium. - The heat medium-
refrigerant heat exchanger 117 n is also connected to the discharge port of thecompressor 112 m and the liquidrefrigerant pipe 131 extending to the heatsource-sideliquid pipe portion 310 of thevalve unit 200 h. The suction port of thecompressor 112 m is connected to thegas refrigerant pipe 132 extending to the low-pressuregas pipe portion 320. - Hence, the
compressor 112 m, the heat medium-refrigerant heat exchanger 117 n, theindoor heat exchangers 122 m, and the pipes connecting them form thesecond circuit 106 n which circulates the first refrigerant. - The
HEX unit 101 n is installed in thefirst space 931 h, thecompressor unit 111 n and thevalve unit 200 h are installed in thesecond space 932 h, and the utilization-side units 120 are installed in thetarget space 933 h. Any of thesafety systems 700h air conditioning system 100 n. - With the above configuration, it is possible to improve the safety of the air conditioning system of a water-cooling type regarding refrigerant leakage. The configuration of the sixth embodiment may be combined with the configuration of the fifth embodiment. In this case, the
compressor unit 111 n further has therefrigerant heat exchanger 114 m and part of therefrigerant pipes pump 116 m), and include a refrigerant circuit for circulating the first refrigerant between thecompressor 112 h and therefrigerant heat exchanger 114 m. - (Other Modifications of Fifth to Seventh Embodiments)
- In the above-mentioned fifth to seventh embodiments, the configurations are explained in which a forced ventilation of the
second space 932 h is performed when a refrigerant leakage has been detected. Yet, a natural ventilation may be utilized instead of performing the forced ventilation. -
FIG. 23 is a schematic configuration diagram of another variation of the safety system according to any one of the fifth to seventh embodiments. - As shown in
FIG. 23 , asafety system 700 p as a variation may have the same configuration as the first embodiment except that theventilator 730 is replaced with adamper 440. Both thedampers 440 disposed to the first andsecond airflow passages central controller 800 p corresponding to thecentral controller 800 h of the fifth embodiment and may have the same hardware configuration as thecentral controller 800 h. Thecentral controller 800 p is configured to perform basically the same operation as thecentral controller 800 h. However, thecentral controller 800 p does not perform the operation of step S3030 h, and instead, control both thedampers 440 to open in step 3040 h. - In other words, the
safety system 700 p has a passage control structure that is configured to, when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, switch a state of the first andsecond airflow passages passages - Thus, as with the safety systems already explained, the
safety system 700 p can also switch the state of the second space from a first state to a second state in which a ventilation of thesecond space 932 h is promoted more than in the first state when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold. Although the ventilation achieved would be weaker than when a forced ventilation is performed, it is possible to reduce the cost of the safety system since a ventilator can be omitted. - Instead of the damper or
dampers 440, any other mechanism which can switch the state of the first and/orsecond airflow passage central controller 800 m by means of an electric motor or the like. - In addition, other various modifications of the air conditioning systems explained above may also be conceivable. For instance, the compressor unit and the valve unit may be integrated to a single unit. In this case, the safety systems as shown in
FIGS. 14, 18, 20, and 23 may be suitable. - As already mentioned above, the air conditioning system according to any of fifth to seventh embodiments may have the three-pipe configuration. The air conditioning system may include a plurality of the valve units as with the first to fourth embodiments, and, between the valve unit and the utilization-
side units 120, one or more of the other valve units may be disposed. In particular when two or more of the valve units are installed in the second space together with the compressor unit, the casings of all of them may be connected by the connection structure. - The heatsource-side
liquid pipe portion 310 and the gas pipe portion orportions side units 120 but directed towards only one among the utilization-side units 120. Yet, when the valve unit has at least a liquid refrigerant pipe portion, a gas refrigerant pipe portion, a liquid control valve disposed in the liquid refrigerant pipe portion, and a gas control valve disposed in the gas refrigerant pipe portion within the casing, the safety system can improve the safety regarding refrigerant leakage of the air conditioning system. - The first space, the second space, and the target space need not necessarily belong to the same building. Thus, for instance, the HEX unit may be installed on a ground outside a building, and/or the first space and the second space may be formed in different buildings. The term “building” includes a house, a hut, a ship, or the like.
- The
damper 440 may also be disposed to thefirst opening 420 to which the connectingduct 740 a is connected, as with the second embodiment as shown inFIG. 6 . - The number of the air passage, the number of the HEX unit connected to each compressor unit, the number of the compressor unit connected to each HEX unit, the number of the utilization-side unit connected to each compressor unit, the number of the utilization-side unit belonging to each unit family, and the number of the each of the first space, the second space, and the target space are not limited to those explained above. The utilization-side units belonging to the same valve unit may be installed different target spaces.
- While only selected embodiments and modifications have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, unless specifically stated otherwise, the size, shape, location, or orientation of the various components can be changed as needed and/or desired so long as the changes do not substantially affect their intended function. Unless specifically stated otherwise, components that are shown directly connected or contacting each other can have intermediate structures disposed between them so long as the changes do not substantially affect their intended function. The functions of one element can be performed by two, and vice versa unless specifically stated otherwise. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Thus, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only.
-
-
- 100, 100 h, 100 m, 100 n: Air Conditioning System
- 101 h, 101 m, 101 n: HEX Unit (Heat Exchanger Unit)
- 102 h, 102 m, 102 n: Outdoor Heat Exchanger
- 103 m: Unit Liquid Refrigerant Pipe (First Connection Pipe)
- 104 m: Unit Gas Refrigerant Pipe (First Connection Pipe)
- 105 m, 105 n: First Circuit
- 106 m, 106 m: Second Circuit
- 107 n: Supply Pipe (First Connection Pipe)
- 108 n: Return Pipe (First Connection Pipe)
- 110, 110 h, 110 m: Heatsource-Side Unit
- 111 h, 111 m, 111 n: Compressor Unit
- 112 h, 112 m: Compressor
- 113 h, 113 m: Switching Mechanism
- 114 m: Refrigerant Heat Exchanger
- 116 m, 118 n: Pump
- 117 n: Heat Medium-Refrigerant Heat Exchanger
- 120, 120 m: Utilization-Side Unit (Indoor Unit)
- 121, 121 m: Unit Family
- 122 h, 122 m: Indoor Heat Exchanger
- 131, 131 m: Liquid Refrigerant Pipe (Second Connection Pipe)
- 132, 132 m: Low-Pressure Gas Refrigerant Pipe (Second Connection Pipe)
- 133: High-Pressure Gas Refrigerant Pipe
- 141: Heatsource-Side Liquid Pipe
- 142: Heatsource-Side Low-Pressure Gas Pipe
- 143: Heatsource-Side High-Pressure Gas Pipe
- 151, 151 m: Utilization-Side Liquid Refrigerant Pipe (Second Connection Pipe)
- 152, 152 m: Utilization-Side Gas Refrigerant Pipe (Second Connection Pipe)
- 200, 200 d, 200 h, 200 m: Valve Unit
- 300: Multi Branch Selector
- 310, 310 m: Heatsource-Side Liquid Pipe Portion
- 311, 311 m: Utilization-Side Liquid Pipe Portion (Liquid Refrigerant Pipe Portion)
- 320, 320 m: Low-Pressure Gas Pipe Portion (Gas Refrigerant Pipe Portion)
- 321: Low-Pressure Gas Sub Pipe (Gas Refrigerant Pipe Portion)
- 330, 330 m: Utilization-Side Gas Pipe Portion (Gas Refrigerant Pipe Portion)
- 340: High-Pressure Gas Pipe Portion (Gas Refrigerant Pipe Portion)
- 341: High-Pressure Gas Sub Pipe (Gas Refrigerant Pipe Portion)
- 351: Bypass Pipe
- 352: Refrigerant Heat Exchanger
- 361: Low-Pressure Gas Control Valve (Gas Control Valve)
- 362: High-Pressure Gas Control Valve (Gas Control Valve)
- 363: Expansion Mechanism
- 364, 364 m: Liquid Shut-Off Valve (Liquid Control Valve)
- 365, 365 m: Gas Shut-Off Valve (Gas Control Valve)
- 370: Pipe Connection Part
- 400: Casing
- 401: Internal Space
- 410: Pipe Aperture
- 420: First Opening
- 430: Second Opening
- 440: Damper (Check Air Damper, Ventilation Control Structure, Passage Control Structure, Discharge Structure)
- 450: Insulator
- 500: Refrigerant Leakage Detector (First Leakage detector)
- 501 m: First Leakage Detector
- 502 m: Second Leakage Detector
- 600, 600 m: Unit Controller (Controller, Ventilation Control Structure, Discharge Structure)
- 700, 700 a, 700 b, 700 c, 700 h, 700 i, 700 j, 700 k, 700 m, 700 p: Safety System
- 701 c: Section
- 710: Individual Ducts (Connection Structure)
- 720, 720 a, 720 b: Shared Duct (Discharge Structure, Ventilation Control Structure)
- 730: Ventilator (Discharge Structure, Ventilation Control Structure)
- 740 a: Connecting Duct (Connection Structure)
- 750 i: Intake Duct (Ventilation Control Structure)
- 800, 800 a, 800 b, 800 c, 800 h, 800 i, 800 m: Central Controller (Controller, Ventilation Control Structure, Discharge Structure)
- 801: Communication Path
- 910 b, 910 c: Grouping Table
- 931 h: First Space
- 932 h: Second Space
- 933 h: Target Space
- 934 h: Building Structure
- 935 h: First Airflow Passage
- 936 h: Second Airflow Passage
- 937 j: Third Airflow Passage
-
- [PTL 1]
EP 3 091 314 A
Claims (20)
1. An air conditioning system comprising:
a compressor unit that has a compressor configured to compress first refrigerant;
a heat exchanger unit that has an outdoor heat exchanger configured to exchange heat between air and the first refrigerant or between air and heat medium, the heat medium being subjected to a heat exchange with the first refrigerant;
at least one indoor unit that has an indoor heat exchanger configured to exchange heat between the first refrigerant and air in a target space to be air-conditioned or between second refrigerant and air in the target space, the second refrigerant being subjected to a heat exchange with the first refrigerant; and
at least one valve unit that has at least one liquid refrigerant pipe portion and at least one gas refrigerant pipe portion configured to allow the first refrigerant or the second refrigerant to flow therein between the compressor unit and the indoor unit, at least one liquid control valve disposed in the liquid refrigerant pipe portion, and at least one gas control valve disposed in the gas refrigerant pipe portion,
wherein:
the heat exchanger unit is installed in a first space;
the compressor unit and the valve unit are installed in a second space which is different from any of the target space and the first space; and
the air conditioning system further comprises
a first leakage detector that is disposed in the second space and configured to detect at least a concentration of the first refrigerant in air, and
a ventilation control structure that is configured to switch the state of the second space from a first state to a second state when the detected concentration of the first refrigerant is equal to or greater than a first detection value threshold, in the second state a ventilation of the second space being promoted more than in the first state.
2. The air conditioning system according to claim 1 , wherein
the ventilation control structure includes
a passage control structure that is configured to, when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, switch a state of at least one airflow passage between the second space and an outer space outside of the second space from a first passage state to a second passage state, in the second passage state air being allowed to pass through the passage more easily than in the first passage state.
3. The air conditioning system according to claim 1 , wherein
the ventilation control structure includes
a discharge structure that is configured to operate to discharge air from the second space when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold.
4. The air conditioning system according to claim 3 , wherein
the discharge structure includes
a ventilator that is configured to draw air from the second space towards an external space which is different from any of the target space and the second space,
a controller that is configured to control the ventilator to operate when the detected concentration of the first refrigerant is equal to or greater than the first detection value threshold, and
a check air damper that is configured to keep closed an airflow passage between the second space and an outer space outside of the second space, and open the airflow passage when the ventilator is in operation.
5. The air conditioning system according to claim 4 , wherein:
the second space is defined by a building structure; and
the ventilator and the check air damper are disposed to the building structure.
6. The air conditioning system according to claim 4 , further comprising:
first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space;
a connection structure connecting the internal spaces of the first and second casings;
an intake duct connecting the outer space of the second space and the internal space of the first casing; and
a discharge duct connecting the internal space of the second casing and the external space,
wherein
the first leakage detector is disposed in the first or second casing that accommodates the compressor,
the check air damper is disposed to the intake duct, and
the ventilator is disposed to the discharge duct.
7. The air conditioning system according to claim 4 , further comprising:
first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space;
a first intake duct connecting the outer space of the second space and the internal space of the first casing;
a second intake duct connecting the outer space of the second space and the internal space of the second casing;
a connection structure connecting the internal spaces of the first and second casings;
a discharge duct connecting the connection structure and the external space,
wherein
the first leakage detector is disposed in the first or second casing that accommodates the compressor,
the check air damper is disposed to each of the first and second intake ducts, and
the ventilator is disposed to the discharge duct.
8. The air conditioning system according to claim 4 , further comprising:
a casing accommodating the compressor unit and the valve unit as part of the second space;
an intake duct connecting the outer space of the second space and the internal space of the casing;
a discharge duct connecting the internal space of the casing and the external space,
wherein
the first leakage detector is disposed in the casing,
the check air damper is disposed to the intake duct, and
the ventilator is disposed to the discharge duct.
9. The air conditioning system according claim 4 , wherein:
the indoor heat exchanger is configured to exchange heat between the second refrigerant and air in the target space;
the liquid refrigerant pipe portion and the gas refrigerant pipe portion of the valve unit are configured to allow the second refrigerant to flow therein;
the air conditioning system further comprises
a second leakage detector that is disposed in the second space and configured to detect at least a concentration of the second refrigerant in air; and
the controller is further configured to control the ventilator to start operating when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold.
10. The air conditioning system according to claim 9 which includes the first and second casings, wherein:
the compressor unit further has a refrigerant heat exchanger configured to exchange heat between the first refrigerant and the second refrigerant;
the first leakage detector is disposed in the first casing; and
the second leakage detector is disposed in the second casing or a space which is part of the second space and not part of the internal spaces of the first and second casings.
11. The air conditioning system according to claim 1 , further comprising:
first connection pipes connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween; and
second connection pipes connecting the compressor unit, the valve unit, and the indoor unit such that the first refrigerant or the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit.
12. The air conditioning system according to claim 1 , wherein:
the air conditioning system comprises a plurality of the indoor units; and
the valve unit further has at least one liquid refrigerant branch pipe branching the liquid refrigerant pipe portion towards the indoor units and at least one gas refrigerant branch pipe branching the gas refrigerant pipe portion towards the indoor units.
13. The air conditioning system according to claim 1 , wherein
the second space is a space which is any one of a machine room, a computer room, and a warehouse in a building.
14. A method for constructing the air conditioning system according to claim 1 , comprising:
installing the compressor unit and the valve unit in the second space which is defined by a building structure of a building;
disposing the first leakage detector in the second space;
installing the heat exchanger unit in the first space;
installing the indoor unit in a space which is within the building and different from the first space and the second space;
connecting the outdoor heat exchanger unit and the compressor unit such that the first refrigerant or the heat medium circulates therebetween;
connecting the compressor unit, the valve unit, and the indoor unit such that the second refrigerant circulates between the compressor unit and the indoor unit via the valve unit; and
installing the ventilation control structure to the building.
15. The method for constructing the air conditioning system according to claim 14 , wherein
the building structure includes a floor, a ceiling facing the floor, at least one wall which connects the floor and the ceiling and surrounds a space between the floor and a ceiling, and a door arranged in the floor, the ceiling, or the wall.
16. The air conditioning system according to claim 5 , further comprising:
first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space;
a connection structure connecting the internal spaces of the first and second casings;
an intake duct connecting the outer space of the second space and the internal space of the first casing; and
a discharge duct connecting the internal space of the second casing and the external space,
wherein
the first leakage detector is disposed in the first or second casing that accommodates the compressor,
the check air damper is disposed to the intake duct, and
the ventilator is disposed to the discharge duct.
17. The air conditioning system according to claim 5 , further comprising:
first and second casings one of which accommodates the compressor unit and another one of which accommodates the valve unit as part of the second space;
a first intake duct connecting the outer space of the second space and the internal space of the first casing;
a second intake duct connecting the outer space of the second space and the internal space of the second casing;
a connection structure connecting the internal spaces of the first and second casings;
a discharge duct connecting the connection structure and the external space,
wherein
the first leakage detector is disposed in the first or second casing that accommodates the compressor,
the check air damper is disposed to each of the first and second intake ducts, and
the ventilator is disposed to the discharge duct.
18. The air conditioning system according to claim 5 , further comprising:
a casing accommodating the compressor unit and the valve unit as part of the second space;
an intake duct connecting the outer space of the second space and the internal space of the casing;
a discharge duct connecting the internal space of the casing and the external space,
wherein
the first leakage detector is disposed in the casing,
the check air damper is disposed to the intake duct, and
the ventilator is disposed to the discharge duct.
19. The air conditioning system according to claim 5 , wherein:
the indoor heat exchanger is configured to exchange heat between the second refrigerant and air in the target space;
the liquid refrigerant pipe portion and the gas refrigerant pipe portion of the valve unit are configured to allow the second refrigerant to flow therein;
the air conditioning system further comprises
a second leakage detector that is disposed in the second space and configured to detect at least a concentration of the second refrigerant in air; and
the controller is further configured to control the ventilator to start operating when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold.
20. The air conditioning system according to claim 6 , wherein:
the indoor heat exchanger is configured to exchange heat between the second refrigerant and air in the target space;
the liquid refrigerant pipe portion and the gas refrigerant pipe portion of the valve unit are configured to allow the second refrigerant to flow therein;
the air conditioning system further comprises
a second leakage detector that is disposed in the second space and configured to detect at least a concentration of the second refrigerant in air; and
the controller is further configured to control the ventilator to start operating when the detected concentration of the second refrigerant is equal to or greater than a second detection value threshold.
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
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EP20196177.8A EP3967938B1 (en) | 2020-09-15 | 2020-09-15 | Safety system and air conditioning system |
EP20196177.8 | 2020-09-15 | ||
EP21196536.3A EP3967939B1 (en) | 2020-09-15 | 2021-09-14 | Air conditioning system and method for constructing the same |
EP21196536.3 | 2021-09-14 | ||
PCT/JP2021/034003 WO2022059722A1 (en) | 2020-09-15 | 2021-09-15 | Air conditioning system and method for constructing the same |
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US18/021,324 Pending US20240011661A1 (en) | 2020-09-15 | 2021-09-15 | Air conditioning system and method for constructing the same |
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US18/021,305 Pending US20230221024A1 (en) | 2020-09-15 | 2021-09-15 | Safety system and method for constructing air conditioning system |
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JP3214051B2 (en) * | 1992-04-13 | 2001-10-02 | 株式会社日立製作所 | Air conditioner |
AU2010364873B2 (en) * | 2010-12-03 | 2014-10-02 | Mitsubishi Electric Corporation | Air-conditioning apparatus |
WO2013038599A1 (en) * | 2011-09-14 | 2013-03-21 | パナソニック株式会社 | Air conditioner |
US9933192B2 (en) * | 2012-12-20 | 2018-04-03 | Mitsubishi Electric Corporation | Air-conditioning apparatus |
JP5812084B2 (en) | 2013-12-11 | 2015-11-11 | ダイキン工業株式会社 | Channel switching collective unit and method for manufacturing channel switching collective unit |
JP6135705B2 (en) * | 2015-04-06 | 2017-05-31 | ダイキン工業株式会社 | User side air conditioner |
EP3153784B1 (en) * | 2015-10-06 | 2017-08-23 | Daikin Europe N.V. | Air conditioner |
JP6827279B2 (en) * | 2016-07-15 | 2021-02-10 | 日立ジョンソンコントロールズ空調株式会社 | Cooling / heating switching unit and air conditioner equipped with it |
CN109791009B (en) * | 2016-09-30 | 2020-07-07 | 大金工业株式会社 | Refrigerating device |
JP7030489B2 (en) * | 2017-11-27 | 2022-03-07 | 三菱重工サーマルシステムズ株式会社 | air conditioner |
US11879650B2 (en) * | 2018-08-06 | 2024-01-23 | Daikin Industries, Ltd. | Air conditioning system |
CN209084999U (en) * | 2018-08-21 | 2019-07-09 | 珠海格力电器股份有限公司 | A kind of unit and isolating device |
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CN116097043A (en) | 2023-05-09 |
EP4105566A1 (en) | 2022-12-21 |
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