US20230096732A1 - Air-conditioning system - Google Patents
Air-conditioning system Download PDFInfo
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- US20230096732A1 US20230096732A1 US17/780,690 US202017780690A US2023096732A1 US 20230096732 A1 US20230096732 A1 US 20230096732A1 US 202017780690 A US202017780690 A US 202017780690A US 2023096732 A1 US2023096732 A1 US 2023096732A1
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- refrigerant
- control valves
- pipe
- indoor
- controller
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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
- 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
- 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
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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
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/49—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring ensuring correct operation, e.g. by trial operation or configuration checks
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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
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
- F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
-
- 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
-
- 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
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
-
- 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
- F24F2140/10—Pressure
- F24F2140/12—Heat-exchange fluid pressure
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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
- 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
- F25B2313/031—Sensor arrangements
- F25B2313/0312—Pressure sensors near the indoor heat exchanger
-
- 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
Definitions
- the present disclosure relates to an air-conditioning system including a plurality of indoor units and an outdoor unit.
- Patent Literature 1 discloses an air-conditioning system including a plurality of indoor units and a plurality of refrigerant leakage detection sensors installed in a room, in which the indoor units are further provided with respective pressure sensors.
- the air-conditioning system when the refrigerant leakage detection sensor detects refrigerant leaking in a room, the air-conditioning system controls the supply of refrigerant to prevent the refrigerant from being supplied to each of the indoor units. Then, the respective pressure sensors detect whether the pressure of refrigerant in their corresponding indoor units has decreased to an atmospheric pressure or to a pressure close to the atmospheric pressure. In Patent Literature 1, due to this operation, the air-conditioning system identifies an indoor unit in which refrigerant leakage has occurred, and continues running of the indoor units other than the identified indoor unit.
- Patent Literature 1 Japanese Patent No. 6428717
- the pressure sensors are provided in the corresponding indoor units. Due to this configuration, in the air-conditioning system in Patent Literature 1, the pressure sensors cannot locate a place where refrigerant leaks in a refrigerant pipe that connects the indoor units and an outdoor unit.
- the present disclosure has been made to solve the above-mentioned problem, and an object of the present disclosure is to provide an air-conditioning system that locates a place where refrigerant leaks in a refrigerant pipe.
- An air-conditioning system includes: a plurality of indoor units configured to condition air in a room; an outdoor unit configured to supply refrigerant to each of the indoor units; a refrigerant pipe including a branch portion from which the refrigerant pipe branches off in parallel for each of the indoor units, the refrigerant pipe connecting each of the indoor units and the outdoor unit through the branch portion, the refrigerant pipe being divided into a plurality of flow sections, the refrigerant pipe being a pipe through which refrigerant flows; a plurality of control valves provided in the refrigerant pipe such that the plurality of control valves are positioned at opposite ends of each of the flow sections, the plurality of control valves being configured to control a flow of refrigerant in the flow sections; a plurality of pressure sensors provided on the refrigerant pipe, and configured to measure a pressure of refrigerant flowing through the refrigerant pipe; and a controller connected to a plurality of the control valves, and configured to control
- the controller compares the pressure of refrigerant measured by each of the indoor-side pressure sensors to a predetermined threshold in the flow section in which the indoor-unit control valve and the indoor-side pipe control valve are positioned at opposite ends.
- the controller compares the pressure of refrigerant measured by the indoor-side pressure sensor to the predetermined threshold. Due to this operation, the controller detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system can locate where refrigerant leaks in the refrigerant pipe.
- FIG. 1 is a circuit diagram illustrating an air-conditioning system 1 according to Embodiment 1.
- FIG. 2 is a circuit diagram illustrating a control box 5 a according to Embodiment 1.
- FIG. 3 is a functional block diagram illustrating a controller 9 according to Embodiment 1.
- FIG. 4 is a flowchart illustrating the operation of the controller 9 according to Embodiment 1.
- FIG. 5 is a circuit diagram illustrating an air-conditioning system 101 according to Embodiment 2.
- FIG. 6 is a functional block diagram illustrating a controller 109 according to Embodiment 2.
- FIG. 7 is a circuit diagram illustrating an air-conditioning system 201 according to Embodiment 3.
- FIG. 1 is a circuit diagram illustrating the air-conditioning system 1 according to Embodiment 1.
- the air-conditioning system 1 will be described below.
- suffixes “a,” “b,” and “c” are used.
- the suffixes are used to distinguish a plurality of identical components from each other.
- the identical components which are denoted by the same reference numeral with different suffixes, are equivalent to each other.
- a component denoted by a reference numeral, but without a suffix, is represented as a collective term for a plurality of identical components. As illustrated in FIG.
- the air-conditioning system 1 includes indoor units 2 , an outdoor unit 3 , a refrigerant pipe 4 , control boxes 5 , control valves 6 , refrigerant leakage detection sensors 7 , pressure sensors 8 , and controllers 9 .
- the air-conditioning system 1 includes two indoor units 2 a, two indoor units 2 b , and two indoor units 2 c. Note that while FIG. 1 illustrates six indoor units 2 , the air-conditioning system 1 may include two to five indoor units 2 , or may include seven or more indoor units 2 .
- the indoor units 2 are configured to condition air in a room.
- Each of the indoor units 2 includes an indoor heat exchanger and an indoor fan (both of which are not illustrated).
- the indoor heat exchanger is configured to cause heat exchange to be performed between room air and refrigerant.
- the indoor heat exchanger functions as an evaporator during cooling operation, and functions as a condenser during heating operation.
- the indoor fan is a device to deliver room air to the indoor heat exchanger.
- the outdoor unit 3 is configured to supply refrigerant to each of the indoor units 2 .
- FIG. 1 illustrates one outdoor unit 3
- the outdoor unit 3 includes a compressor, a flow switching device, an outdoor heat exchanger, an outdoor fan, and an expansion unit (all of which are not illustrated).
- the compressor is configured to suck refrigerant in a low-temperature and low-pressure state, compress the sucked refrigerant into a high-temperature and high-pressure state, and discharge the compressed refrigerant.
- the flow switching device is configured to change the flow direction of refrigerant, and is, for example, a four-way valve.
- the outdoor heat exchanger is configured to cause heat exchange to be performed between refrigerant and outside air, and is, for example, a fin-and-tube heat exchanger.
- the outdoor heat exchanger functions as a condenser during cooling operation, and functions as an evaporator during heating operation.
- the outdoor fan is a device configured to deliver outside air to the outdoor heat exchanger.
- the expansion unit is a pressure reducing valve or an expansion valve to reduce the pressure of refrigerant and expand the refrigerant.
- the refrigerant pipe 4 is a pipe through which refrigerant flows.
- the refrigerant pipe 4 includes branch portions 11 from which the refrigerant pipe 4 branches off in parallel for each of the indoor units 2 .
- the refrigerant pipe 4 connects each of the indoor units 2 and the outdoor unit 3 through the branch portions 11 .
- the refrigerant pipe 4 branches off from the branch portions 11 to individual indoor units 2 .
- a branch portion 11 a is connected in series to a branch portion 11 b and a branch portion 11 c.
- the refrigerant pipe 4 is divided into a plurality of flow sections.
- a flow section is a minimum unit for which a flow of refrigerant is controlled.
- the refrigerant pipe 4 may branch off from the branch portions 11 to individual groups of plural indoor units 2 such as on each floor of the building, Among the branch portions 11 , the branch portion “b” and the branch portion “c” may be connected in parallel to the branch portion “a.” Further, a smaller number of branches may extend from the branch portions 11 toward the indoor units 2 than the number of branches extending from the branch portions 11 toward the outdoor unit 3 . There may be one branch portion 11 .
- FIG. 2 is a circuit diagram illustrating a control box 5 a according to Embodiment 1.
- the air-conditioning system 1 includes the control box 5 a, a control box 5 b, and a control box 5 c.
- the control box 5 a is a container in which the branch portion 11 a, a pipe control valve 13 a, and a controller 9 a are accommodated.
- the pipe control valve 13 a is included in the control valves 6 that will be described later.
- the control box 5 a is connected to a refrigerant leakage detection sensor 7 a and indoor-side pressure sensors 21 a by a communication line 31 .
- the indoor-side pressure sensors 21 a are included in the pressure sensors 8 that will be described later.
- the control box 5 a is further connected to the indoor units 2 a by the communication line 31 .
- the indoor units 2 a are connected to the branch portion 11 a, Note that the control box 5 a may have the indoor-side pressure sensors 21 a accommodated therein. Further, the air-conditioning system 1 may not necessarily include the control boxes 5 .
- the air-conditioning system 1 includes a plurality of control valves 6 .
- the control valves 6 are configured to control a flow of refrigerant.
- the control valves 6 may be a solenoid valve that can linearly adjust the flow amount of refrigerant, or may be an opening-closing valve capable of solely being fully closed or fully opened.
- the control valves 6 are provided in the refrigerant pipe 4 such that the control valves 6 are positioned at opposite ends of each of the flow sections.
- the control valves 6 include indoor-unit control valves 12 a, indoor-unit control valves 12 b, and indoor-unit control valves 12 c, and also include the pipe control valve 13 a, a pipe control valve 13 b, and a pipe control valve 13 c.
- Pipe control valves 13 are provided in the refrigerant pipe 4 .
- the pipe control valve 13 a is accommodated in the control box 5 a, and connected to the controller 9 a by a communication line (not illustrated).
- the pipe control valve 13 a includes indoor-side pipe control valves 41 a and an outdoor-side pipe control valve 42 a.
- a pipe control valve 13 b includes indoor-side pipe control valves 41 b and an outdoor-side pipe control valve 42 b.
- a pipe control valve 13 c includes indoor-side pipe control valves 41 c and an outdoor-side pipe control valve 42 c,
- the indoor-side pipe control valves 41 a are provided between the branch portion 11 a and the indoor units 2 a.
- the indoor-side pipe control valve 41 a is provided between the branch portion 11 a and the indoor unit 2 b.
- the indoor-side pipe control valves 41 a may only be provided between the branch portion 11 a and either of the indoor units 2 a, and between the branch portion 11 a and the indoor unit 2 b.
- the outdoor-side pipe control valve 42 a is provided between the branch portion 11 a and the outdoor unit 3 .
- the pipe control valves 13 may not necessarily include indoor-side pipe control valves 41 or outdoor-side pipe control valves 42 . In this case, one pipe control valve 13 is provided at each branch point of the branch portions 11 , and consequently the number of the pipe control valves 13 decreases.
- the air-conditioning system 1 includes a refrigerant leakage detection sensor 7 a, a refrigerant leakage detection sensor 7 b, and a refrigerant leakage detection sensor 7 c.
- the refrigerant leakage detection sensors 7 are configured to detect refrigerant leakage from the refrigerant pipe 4 .
- the refrigerant leakage detection sensor 7 a detects refrigerant leakage by targeting the refrigerant pipe 4 connected to the indoor units 2 a through the branch portion 11 a.
- the refrigerant leakage detection sensors 7 are installed indoors where a detection-target refrigerant pipe 4 is installed. Note that the air-conditioning system 1 may not necessarily include the refrigerant leakage detection sensors 7 .
- the air-conditioning system 1 includes a pressure sensor 8 a, a pressure sensor 8 b, and a pressure sensor 8 c.
- the pressure sensors 8 are provided on the refrigerant pipe 4 to measure the pressure of refrigerant flowing through the refrigerant pipe 4 .
- the pressure sensor 8 a includes a plurality of indoor-side pressure sensors 21 a.
- the pressure sensor 8 b includes a plurality of indoor-side pressure sensors 21 b.
- the pressure sensor 8 c includes a plurality of indoor-side pressure sensors 21 c.
- Each of the indoor-side pressure sensors 21 a is assigned with a sensor count. The sensor count refers to the number used for the controller 9 a to identify each of the indoor-side pressure sensors 21 a in turn.
- the indoor-side pressure sensors 21 a are provided between the indoor-unit control valves 12 a and the indoor-side pipe control valves 41 a.
- the indoor-side pressure sensor 21 a is provided between the indoor-unit control valve 12 b and the indoor-side pipe control valve 41 a.
- the air-conditioning system 1 includes the controller 9 a, a controller 9 b, and a controller 9 c.
- the controller 9 a is connected to the pipe control valve 13 a by a communication line (not illustrated) to control the pipe control valve 13 a.
- the communication line 31 connected to the control box 5 a is connected to the controller 9 a. That is, the controller 9 a is connected to the refrigerant leakage detection sensor 7 a, the pressure sensor 8 a, and the indoor units 2 a through the communication line 31 to communicate with them.
- the controller 9 a communicates with the indoor units 2 a to control the indoor-unit control valves 12 a.
- the controller 9 a may control the indoor-unit control valves 12 a through the respective controllers included in the indoor units 2 a.
- the controller 9 a is connected to the controller 9 b by the communication line 31 .
- the controller 9 b or the controller 9 c may be omitted.
- the controller 9 a may control the indoor-unit control valves 12 b and the pipe control valve 13 b instead of the controller 9 b controlling them, or the controller 9 a may control the indoor-unit control valves 12 c and the pipe control valve 13 c instead of the controller 9 c controlling them.
- the controller 9 a may be accommodated in the indoor unit 2 , the outdoor unit 3 , or other device, or may be provided separately as an external unit.
- Each of the controllers 9 includes dedicated hardware or a central processor (CPU, also referred to as “processor,” “computer,” “microprocessor,” “microcomputer,” or “processor”) configured to execute programs stored in a memory.
- CPU central processor
- the controller 9 a is dedicated hardware, the controller 9 a is equivalent to, for example, a single circuit, a combined circuit, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof.
- the functional units of the controller 9 may be individually implemented by separate units of hardware, or the functional units of the controller 9 may be implemented together by a single unit of hardware.
- the functions to be executed by the controller 9 are implemented by software, firmware, or a combination of the software and the firmware.
- the software and firmware are described as programs and stored in a memory (not illustrated).
- the CPU reads and executes the programs stored in the memory, thereby implementing the functions of the controller 9 .
- the memory is a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM.
- the functions of the controller 9 may be partially implemented by dedicated hardware, while being partially implemented by software or firmware.
- FIG. 3 is a functional block diagram illustrating the controller 9 according to Embodiment 1. As illustrated in FIG. 3 , the controller 9 includes an opening-closing unit 32 , a first comparison unit 33 , and a first detection unit 34 .
- the opening-closing unit 32 , the first comparison unit 33 , and the first detection unit 34 are made up of algorithms.
- the opening-closing unit 32 doses the control valves 6 connected to the controller 9 .
- the opening-dosing unit 32 may be configured to be started by a worker providing an instruction to start.
- the opening-closing unit 32 may be automatically started at the designated date and time according to the schedule set by a worker.
- the opening-closing unit 32 opens the control valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected by the first detection unit 34 . Note that the opening-closing unit 32 does not open the control valve 6 positioned between the flow section where refrigerant leakage is not detected and the flow section where refrigerant leakage is detected.
- the first comparison unit 33 compares a pressure of refrigerant to a predetermined threshold.
- the pressure of refrigerant is measured by the indoor-side pressure sensor 21 , assigned with a sensor count equal to the target count, in the flow section in which the control valves 6 closed by the opening-closing unit 32 are positioned at opposite ends.
- the target count is a serial number representing a target indoor-side pressure sensor 21 on which the controller 9 performs processing.
- the first detection unit 34 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor 21 is determined to be lower than the predetermined threshold by the first comparison unit 33 .
- the controllers 9 accommodated in the respective control boxes 5 cooperate with each other by communicating with each other to identify the flow section where refrigerant leaks. Further, the controllers 9 accommodated in the respective control boxes 5 cooperate with each other by communicating with each other in such a manner as to maintain the control valves 6 in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected, and as to open the control valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected, Note that the controllers 9 may display the location where refrigerant leaks or display information that the indoor units 2 stop operating on a remote control (not illustrated) included in the indoor units 2 , a centralized controller (not illustrated) connected to the outdoor unit 3 , or other controller.
- FIG. 4 is a flowchart illustrating the operation of the controller 9 according to Embodiment 1.
- the procedure for detecting the location of refrigerant leakage by the controller 9 a is now described.
- the opening-closing unit 32 in the controller 9 a doses the indoor-side pipe control valves 41 a and the outdoor-side pipe control valve 42 a (step S 1 ).
- the opening-closing unit 32 in the controller 9 a closes the indoor-unit control valves 12 a (step S 2 ).
- the opening-closing unit 32 communicates with the controller 9 b to instruct the controller 9 b to close the outdoor-side pipe control valve 42 b accommodated in the control box 5 b (step S 3 ).
- the first comparison unit 33 determines whether the target count exceeds the last sensor count assigned to the indoor-side pressure sensor 21 a (step S 4 ). When the target count does not exceed the last sensor count (NO in step S 4 ), the first comparison unit 33 determines whether the pressure, detected by the indoor-side pressure sensor 21 a assigned with a sensor count equal to the target count, is lower than the threshold (step S 5 ). The pressure of refrigerant measured by the indoor-side pressure sensor 21 a is higher than the threshold (NO in step S 5 ), the opening-closing unit 32 opens the indoor-unit control valve 12 a and the indoor-side pipe control valve 41 a that are positioned at opposite ends of the flow section in which the indoor-side pressure sensor 21 a is provided (step S 6 ).
- the controller 9 a communicates with the controller 9 b to inform that there is no influence of refrigerant (step S 7 ). Upon receiving the communication, the controller 9 b performs operation to detect the location of refrigerant leakage. As described above, in a case where a plurality of controllers 9 are provided, all the controllers 9 detect the location of refrigerant leakage.
- the pressure of refrigerant measured by the indoor-side pressure sensor 21 a is lower than the threshold (YES in step S 5 ), the first detection unit 34 detects refrigerant leakage in the flow section where the indoor-side pressure sensor 21 a is provided (step S 8 ). Further, the controller 9 a maintains the indoor-unit control valve 12 a and the indoor-side pipe control valve 41 a in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected (step S 9 ). Then, the controller 9 a increments the target count (step S 10 ).
- the controller 9 a determines whether any of the indoor-side pipe control valves 41 a is opened (step S 11 ). When at least one of the indoor-side pipe control valves 41 a is opened (YES in step S 11 ), the opening-closing unit 32 opens the outdoor-side pipe control valve 42 a (step S 12 ). When any of the indoor-side pipe control valves 41 a is not opened (NO in step S 11 ), the controller 9 a does not change the current opened or closed state of the indoor-side pipe control valves 41 a or the outdoor-side pipe control valve 42 a. Thereafter, the controller 9 a communicates with the outdoor unit 3 and the control box 5 b to inform that detection of the location of refrigerant leakage has ended (step S 13 ).
- the controller 9 compares the pressure of refrigerant measured by each of the indoor-side pressure sensors 21 to a predetermined threshold in the flow section in which the indoor-unit control valve 12 and the indoor-side pipe control valve 41 are positioned at opposite ends.
- the controller 9 compares the pressure of refrigerant measured by the indoor-side pressure sensor 21 to the predetermined threshold. Due to this operation, the controller 9 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor 21 is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system 1 can locate where refrigerant leaks in the refrigerant pipe 4 .
- the controller 9 opens the control valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected.
- refrigerant flows through the flow section of the refrigerant pipe 4 where refrigerant does not leak. Therefore, the air-conditioning system 1 can continue running by using the refrigerant pipe 4 excluding the flow section where refrigerant leaks.
- the air-conditioning system 1 includes the control boxes 5 .
- the branch portions 11 , the pipe control valves 13 , and the controllers 9 are accommodated.
- management of the pipe control valves 13 and the controllers 9 is complicated.
- the branch portions 11 the pipe control valves 13 , and the controllers 9 are accommodated in the corresponding control boxes 5 , so that the branch portions 11 the control valves 6 , and the controllers 9 are managed based on each control box 5 . Therefore, the air-conditioning system 1 improves the ease of maintenance, and can immediately deal with refrigerant leakage to thereby minimize the influence of refrigerant leakage.
- Embodiment 1 when the refrigerant leakage detection sensor 7 detects refrigerant leaking from the refrigerant pipe 4 , the pressure sensor 8 measures the pressure of refrigerant. Due to this operation, the air-conditioning system 1 can immediately locate where refrigerant leaks in the refrigerant pipe 4 . Therefore, the air-conditioning system 1 can immediately deal with the refrigerant leakage to thereby minimize the influence of refrigerant leakage.
- the controller 9 maintains the control valves 6 in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected. This prevents refrigerant from flowing to the flow section where refrigerant leakage is detected. Therefore, further refrigerant leakage can be prevented after the control valves 6 are closed.
- the one of the controllers 9 When one of the controllers 9 receives communication from the other of the controllers 9 , the one of the controllers 9 controls a plurality of the control valves 6 connected to the one of the controllers 9 .
- a plurality of controllers 9 cooperating with each other by communicating with each other make a comparison of the pressure of refrigerant in the flow sections to the threshold in turn. Therefore, the air-conditioning system 1 can efficiently locate where refrigerant leaks in the refrigerant pipe 4 in its entirety.
- the controller 9 may set a predetermined time interval at which the pressure sensor 8 measures the pressure of refrigerant. Due to this operation, the air-conditioning system 1 can automatically perform regular maintenance. Therefore, the air-conditioning system 1 can reduce the maintenance load. For example, in a case where the air-conditioning system 1 uses refrigerant with a high level of safety such as a flammable refrigerant, the air-conditioning system 1 can omit the refrigerant leakage detection sensor 7 . In this case, the air-conditioning system 1 can reduce the number of facilities needed, and can improve the design flexibility.
- a high level of safety such as a flammable refrigerant
- FIG. 5 is a circuit diagram illustrating an air-conditioning system 101 according to Embodiment 2.
- FIG. 6 is a functional block diagram illustrating a controller 109 according to Embodiment 2.
- the present Embodiment 2 is different from Embodiment 1 in that the outdoor unit 3 is provided with an outdoor-unit control valve 14 .
- the same components as those in Embodiment 1 are denoted by the same reference signs, and thus descriptions thereof are omitted.
- the differences from Embodiment 1 are mainly described below.
- the control valve 6 includes the outdoor-unit control valve 14 .
- the outdoor-unit control valve 14 is provided in the outdoor unit 3 to control a flow of refrigerant.
- An outdoor-side pressure sensor 22 is provided between the outdoor-unit control valve 14 and the outdoor-side pipe control valve 42 to measure the pressure of refrigerant flowing through the refrigerant pipe 4 .
- the controller 109 includes a second comparison unit 133 , and a second detection unit 134 .
- the second comparison unit 133 and the second detection unit 134 are made up of algorithms.
- the second comparison unit 133 compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to a predetermined threshold in a plurality of flow sections dosed by the opening-closing unit 32 .
- the second detection unit 134 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the outdoor-side pressure sensor 22 is determined to be lower than the predetermined threshold by the comparison unit.
- a controller 109 a compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to a predetermined threshold in the flow section in which the outdoor-unit control valve 14 and the outdoor-side pipe control valve 42 are positioned at opposite ends.
- the controller 109 compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to the predetermined threshold. Due to this operation, the controller 109 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the outdoor-side pressure sensor 22 is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system 101 can still detect refrigerant leaking even in the refrigerant pipe 4 connecting to the outdoor unit 3 and to the control box 5 .
- FIG. 7 is a circuit diagram illustrating an air-conditioning system 201 according to Embodiment 3.
- the present Embodiment 3 is different from Embodiment 1 in that the air-conditioning system 201 includes a backup pipe 204 .
- the same components as those in Embodiment 1 and Embodiment 2 are denoted by the same reference signs, and thus descriptions thereof are omitted.
- Embodiment 1 differs from Embodiment 1 and Embodiment 2 in that the differences from Embodiment 1 and Embodiment 2 are mainly described below.
- the outdoor unit 3 , the control boxes 5 , and the indoor unit 2 are connected by the refrigerant pipe 4 and the backup pipe 204 .
- the backup pipe 204 runs parallel to the refrigerant pipe 4 , and is used when refrigerant leakage has occurred in the refrigerant pipe 4 .
- the backup pipe 204 is provided at a location where, for example, breakage of or other damage to a pipe is more likely to occur due to the influence exerted on the pipe by the surrounding environment such as vibrations or chemical substances.
- the air-conditioning system 201 includes the backup pipe 204 .
- the air-conditioning system 201 controls the flow of the refrigerant such that the refrigerant flows through the backup pipe 204 running parallel to the refrigerant pipe 4 . Therefore, even when refrigerant leaks, the air-conditioning system 201 can still allow all the indoor units 2 to continue running. While the air-conditioning system 201 continues running, a worker can still repair the pipe.
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Abstract
An air-conditioning system includes a plurality of indoor units, an outdoor unit, a refrigerant pipe including a branch portion and being divided into a plurality of flow sections, a plurality of control valves, a plurality of pressure sensors, and a controller. The control valves include indoor-unit control valves, and a plurality of pipe control valves. The pipe control valves include a plurality of indoor-side pipe control valves provided between the branch portion and the indoor units. The pressure sensors include a plurality of indoor-side pressure sensors connected to the controller and provided between the indoor-unit control valves and the indoor-side pipe control valves. The controller opens or closes the control valves, compares a pressure of refrigerant to a predetermined threshold, and detects refrigerant leaking in the flow section where a pressure of refrigerant measured is determined to be lower than the predetermined threshold.
Description
- The present disclosure relates to an air-conditioning system including a plurality of indoor units and an outdoor unit.
- An air-conditioning system has hitherto been known which includes a plurality of indoor units installed on each floor of a budding or in a large room or other space. Such a related-art air-conditioning system as described above may be provided with a refrigerant leakage detection sensor that detects refrigerant leakage to ensure safety when refrigerant leakage occurs.
Patent Literature 1 discloses an air-conditioning system including a plurality of indoor units and a plurality of refrigerant leakage detection sensors installed in a room, in which the indoor units are further provided with respective pressure sensors. In the air-conditioning system disclosed inPatent Literature 1, when the refrigerant leakage detection sensor detects refrigerant leaking in a room, the air-conditioning system controls the supply of refrigerant to prevent the refrigerant from being supplied to each of the indoor units. Then, the respective pressure sensors detect whether the pressure of refrigerant in their corresponding indoor units has decreased to an atmospheric pressure or to a pressure close to the atmospheric pressure. InPatent Literature 1, due to this operation, the air-conditioning system identifies an indoor unit in which refrigerant leakage has occurred, and continues running of the indoor units other than the identified indoor unit. - Patent Literature 1: Japanese Patent No. 6428717
- However, in the air-conditioning system disclosed in
Patent Literature 1, the pressure sensors are provided in the corresponding indoor units. Due to this configuration, in the air-conditioning system inPatent Literature 1, the pressure sensors cannot locate a place where refrigerant leaks in a refrigerant pipe that connects the indoor units and an outdoor unit. - The present disclosure has been made to solve the above-mentioned problem, and an object of the present disclosure is to provide an air-conditioning system that locates a place where refrigerant leaks in a refrigerant pipe.
- An air-conditioning system according to an embodiment of the present disclosure includes: a plurality of indoor units configured to condition air in a room; an outdoor unit configured to supply refrigerant to each of the indoor units; a refrigerant pipe including a branch portion from which the refrigerant pipe branches off in parallel for each of the indoor units, the refrigerant pipe connecting each of the indoor units and the outdoor unit through the branch portion, the refrigerant pipe being divided into a plurality of flow sections, the refrigerant pipe being a pipe through which refrigerant flows; a plurality of control valves provided in the refrigerant pipe such that the plurality of control valves are positioned at opposite ends of each of the flow sections, the plurality of control valves being configured to control a flow of refrigerant in the flow sections; a plurality of pressure sensors provided on the refrigerant pipe, and configured to measure a pressure of refrigerant flowing through the refrigerant pipe; and a controller connected to a plurality of the control valves, and configured to control a plurality of the control valves, wherein the control valves include indoor-unit control valves provided in a plurality of the indoor units, and a plurality of pipe control valves provided in the refrigerant pipe, wherein the pipe control valves include a plurality of indoor-side pipe control valves provided between the branch portion and the indoor units, the pressure sensors include a plurality of indoor-side pressure sensors connected to the controller and provided between the indoor-unit control valves and the indoor-side pipe control valves, and the controller includes an opening-closing unit configured to open or close the control valves connected to the controller, a first comparison unit configured to compare a pressure of refrigerant to a predetermined threshold, the pressure of refrigerant being measured by each of the indoor-side pressure sensors, in a plurality of the flow sections where the control valves closed by the opening-closing unit are positioned at opposite ends, and a first detection unit configured to detect refrigerant leaking in the flow section where a pressure of refrigerant measured by each of the indoor-side pressure sensors is determined to be lower than the predetermined threshold by the first comparison unit.
- According to an embodiment of the present disclosure, the controller compares the pressure of refrigerant measured by each of the indoor-side pressure sensors to a predetermined threshold in the flow section in which the indoor-unit control valve and the indoor-side pipe control valve are positioned at opposite ends. In general, when refrigerant leaks from a refrigerant pipe, the pressure of refrigerant flowing through the refrigerant pipe decreases. As described above, the controller according to an embodiment of the present disclosure compares the pressure of refrigerant measured by the indoor-side pressure sensor to the predetermined threshold. Due to this operation, the controller detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system can locate where refrigerant leaks in the refrigerant pipe.
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FIG. 1 is a circuit diagram illustrating an air-conditioning system 1 according toEmbodiment 1. -
FIG. 2 is a circuit diagram illustrating acontrol box 5 a according toEmbodiment 1. -
FIG. 3 is a functional block diagram illustrating a controller 9 according toEmbodiment 1. -
FIG. 4 is a flowchart illustrating the operation of the controller 9 according toEmbodiment 1. -
FIG. 5 is a circuit diagram illustrating an air-conditioning system 101 according toEmbodiment 2. -
FIG. 6 is a functional block diagram illustrating acontroller 109 according toEmbodiment 2. -
FIG. 7 is a circuit diagram illustrating an air-conditioning system 201 according toEmbodiment 3. - Embodiments of an air-
conditioning system 1 will be described hereinafter with reference to the drawings.FIG. 1 is a circuit diagram illustrating the air-conditioning system 1 according toEmbodiment 1. With reference toFIG. 1 , the air-conditioning system 1 will be described below. Note that in the descriptions below, suffixes “a,” “b,” and “c” are used. The suffixes are used to distinguish a plurality of identical components from each other. The identical components, which are denoted by the same reference numeral with different suffixes, are equivalent to each other. A component denoted by a reference numeral, but without a suffix, is represented as a collective term for a plurality of identical components. As illustrated inFIG. 1 , the air-conditioning system 1 includesindoor units 2, anoutdoor unit 3, arefrigerant pipe 4,control boxes 5,control valves 6, refrigerant leakage detection sensors 7,pressure sensors 8, and controllers 9. - The air-
conditioning system 1 includes twoindoor units 2 a, twoindoor units 2 b, and twoindoor units 2 c. Note that whileFIG. 1 illustrates sixindoor units 2, the air-conditioning system 1 may include two to fiveindoor units 2, or may include seven or moreindoor units 2. Theindoor units 2 are configured to condition air in a room. Each of theindoor units 2 includes an indoor heat exchanger and an indoor fan (both of which are not illustrated). The indoor heat exchanger is configured to cause heat exchange to be performed between room air and refrigerant. The indoor heat exchanger functions as an evaporator during cooling operation, and functions as a condenser during heating operation. The indoor fan is a device to deliver room air to the indoor heat exchanger. - The
outdoor unit 3 is configured to supply refrigerant to each of theindoor units 2. Note that whileFIG. 1 illustrates oneoutdoor unit 3, two or moreoutdoor units 3 may be provided. Theoutdoor unit 3 includes a compressor, a flow switching device, an outdoor heat exchanger, an outdoor fan, and an expansion unit (all of which are not illustrated). The compressor is configured to suck refrigerant in a low-temperature and low-pressure state, compress the sucked refrigerant into a high-temperature and high-pressure state, and discharge the compressed refrigerant. The flow switching device is configured to change the flow direction of refrigerant, and is, for example, a four-way valve. The outdoor heat exchanger is configured to cause heat exchange to be performed between refrigerant and outside air, and is, for example, a fin-and-tube heat exchanger. The outdoor heat exchanger functions as a condenser during cooling operation, and functions as an evaporator during heating operation. The outdoor fan is a device configured to deliver outside air to the outdoor heat exchanger. The expansion unit is a pressure reducing valve or an expansion valve to reduce the pressure of refrigerant and expand the refrigerant. - The
refrigerant pipe 4 is a pipe through which refrigerant flows. Therefrigerant pipe 4 includesbranch portions 11 from which the refrigerant pipe 4 branches off in parallel for each of theindoor units 2. Therefrigerant pipe 4 connects each of theindoor units 2 and theoutdoor unit 3 through thebranch portions 11. The refrigerant pipe 4 branches off from thebranch portions 11 to individualindoor units 2. Abranch portion 11 a is connected in series to abranch portion 11 b and a branch portion 11 c. Therefrigerant pipe 4 is divided into a plurality of flow sections. A flow section is a minimum unit for which a flow of refrigerant is controlled. - Note that the
refrigerant pipe 4 may branch off from thebranch portions 11 to individual groups of pluralindoor units 2 such as on each floor of the building, Among thebranch portions 11, the branch portion “b” and the branch portion “c” may be connected in parallel to the branch portion “a.” Further, a smaller number of branches may extend from thebranch portions 11 toward theindoor units 2 than the number of branches extending from thebranch portions 11 toward theoutdoor unit 3. There may be onebranch portion 11. -
FIG. 2 is a circuit diagram illustrating acontrol box 5 a according toEmbodiment 1. The air-conditioning system 1 includes thecontrol box 5 a, acontrol box 5 b, and a control box 5 c. As illustrated inFIG. 2 , thecontrol box 5 a is a container in which thebranch portion 11 a, apipe control valve 13 a, and acontroller 9 a are accommodated. Thepipe control valve 13 a is included in thecontrol valves 6 that will be described later. As illustrated inFIG. 1 , thecontrol box 5 a is connected to a refrigerantleakage detection sensor 7 a and indoor-side pressure sensors 21 a by acommunication line 31. The indoor-side pressure sensors 21 a are included in thepressure sensors 8 that will be described later. Thecontrol box 5 a is further connected to theindoor units 2 a by thecommunication line 31. Theindoor units 2 a are connected to thebranch portion 11 a, Note that thecontrol box 5 a may have the indoor-side pressure sensors 21 a accommodated therein. Further, the air-conditioning system 1 may not necessarily include thecontrol boxes 5. - The air-
conditioning system 1 includes a plurality ofcontrol valves 6. Thecontrol valves 6 are configured to control a flow of refrigerant. Thecontrol valves 6 may be a solenoid valve that can linearly adjust the flow amount of refrigerant, or may be an opening-closing valve capable of solely being fully closed or fully opened. Thecontrol valves 6 are provided in therefrigerant pipe 4 such that thecontrol valves 6 are positioned at opposite ends of each of the flow sections. Thecontrol valves 6 include indoor-unit control valves 12 a, indoor-unit control valves 12 b, and indoor-unit control valves 12 c, and also include thepipe control valve 13 a, apipe control valve 13 b, and apipe control valve 13 c. -
Pipe control valves 13 are provided in therefrigerant pipe 4. As described above, thepipe control valve 13 a is accommodated in thecontrol box 5 a, and connected to thecontroller 9 a by a communication line (not illustrated). Thepipe control valve 13 a includes indoor-sidepipe control valves 41 a and an outdoor-sidepipe control valve 42 a. Note that apipe control valve 13 b includes indoor-sidepipe control valves 41 b and an outdoor-side pipe control valve 42 b. Further, apipe control valve 13 c includes indoor-sidepipe control valves 41 c and an outdoor-sidepipe control valve 42 c, The indoor-sidepipe control valves 41 a are provided between thebranch portion 11 a and theindoor units 2 a. In addition, the indoor-sidepipe control valve 41 a is provided between thebranch portion 11 a and theindoor unit 2 b. Note that the indoor-sidepipe control valves 41 a may only be provided between thebranch portion 11 a and either of theindoor units 2 a, and between thebranch portion 11 a and theindoor unit 2 b. The outdoor-sidepipe control valve 42 a is provided between thebranch portion 11 a and theoutdoor unit 3. Note that thepipe control valves 13 may not necessarily include indoor-sidepipe control valves 41 or outdoor-sidepipe control valves 42. In this case, onepipe control valve 13 is provided at each branch point of thebranch portions 11, and consequently the number of thepipe control valves 13 decreases. - The air-
conditioning system 1 includes a refrigerantleakage detection sensor 7 a, a refrigerant leakage detection sensor 7 b, and a refrigerant leakage detection sensor 7 c. The refrigerant leakage detection sensors 7 are configured to detect refrigerant leakage from therefrigerant pipe 4. The refrigerantleakage detection sensor 7 a detects refrigerant leakage by targeting therefrigerant pipe 4 connected to theindoor units 2 a through thebranch portion 11 a. The refrigerant leakage detection sensors 7 are installed indoors where a detection-targetrefrigerant pipe 4 is installed. Note that the air-conditioning system 1 may not necessarily include the refrigerant leakage detection sensors 7. - The air-
conditioning system 1 includes apressure sensor 8 a, apressure sensor 8 b, and apressure sensor 8 c. Thepressure sensors 8 are provided on therefrigerant pipe 4 to measure the pressure of refrigerant flowing through therefrigerant pipe 4. Thepressure sensor 8 a includes a plurality of indoor-side pressure sensors 21 a. Thepressure sensor 8 b includes a plurality of indoor-side pressure sensors 21 b. Thepressure sensor 8 c includes a plurality of indoor-side pressure sensors 21 c. Each of the indoor-side pressure sensors 21 a is assigned with a sensor count. The sensor count refers to the number used for thecontroller 9 a to identify each of the indoor-side pressure sensors 21 a in turn. The indoor-side pressure sensors 21 a are provided between the indoor-unit control valves 12 a and the indoor-sidepipe control valves 41 a. In addition, the indoor-side pressure sensor 21 a is provided between the indoor-unit control valve 12 b and the indoor-sidepipe control valve 41 a. - The air-
conditioning system 1 includes thecontroller 9 a, acontroller 9 b, and acontroller 9 c. As described above, thecontroller 9 a is connected to thepipe control valve 13 a by a communication line (not illustrated) to control thepipe control valve 13 a. Thecommunication line 31 connected to thecontrol box 5 a is connected to thecontroller 9 a. That is, thecontroller 9 a is connected to the refrigerantleakage detection sensor 7 a, thepressure sensor 8 a, and theindoor units 2 a through thecommunication line 31 to communicate with them. Thecontroller 9 a communicates with theindoor units 2 a to control the indoor-unit control valves 12 a. Note that in a case where theindoor units 2 a include respective controllers (not illustrated) configured to control the indoor-unit control valves 12 a, thecontroller 9 a may control the indoor-unit control valves 12 a through the respective controllers included in theindoor units 2 a. - The
controller 9 a is connected to thecontroller 9 b by thecommunication line 31. Note that thecontroller 9 b or thecontroller 9 c may be omitted. In this case, thecontroller 9 a may control the indoor-unit control valves 12 b and thepipe control valve 13 b instead of thecontroller 9 b controlling them, or thecontroller 9 a may control the indoor-unit control valves 12 c and thepipe control valve 13 c instead of thecontroller 9 c controlling them. Note that thecontroller 9 a may be accommodated in theindoor unit 2, theoutdoor unit 3, or other device, or may be provided separately as an external unit. - Each of the controllers 9 includes dedicated hardware or a central processor (CPU, also referred to as “processor,” “computer,” “microprocessor,” “microcomputer,” or “processor”) configured to execute programs stored in a memory. When the
controller 9 a is dedicated hardware, thecontroller 9 a is equivalent to, for example, a single circuit, a combined circuit, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof. The functional units of the controller 9 may be individually implemented by separate units of hardware, or the functional units of the controller 9 may be implemented together by a single unit of hardware. - When the controller 9 is the CPU, the functions to be executed by the controller 9 are implemented by software, firmware, or a combination of the software and the firmware. The software and firmware are described as programs and stored in a memory (not illustrated). The CPU reads and executes the programs stored in the memory, thereby implementing the functions of the controller 9. For example, the memory is a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM. Note that the functions of the controller 9 may be partially implemented by dedicated hardware, while being partially implemented by software or firmware.
-
FIG. 3 is a functional block diagram illustrating the controller 9 according toEmbodiment 1. As illustrated inFIG. 3 , the controller 9 includes an opening-closing unit 32, afirst comparison unit 33, and afirst detection unit 34. The opening-closing unit 32, thefirst comparison unit 33, and thefirst detection unit 34 are made up of algorithms. - When the refrigerant leakage detection sensor 7 detects refrigerant leakage, the opening-
closing unit 32 doses thecontrol valves 6 connected to the controller 9. Note that the opening-dosing unit 32 may be configured to be started by a worker providing an instruction to start. The opening-closing unit 32 may be automatically started at the designated date and time according to the schedule set by a worker. Further, the opening-closing unit 32 opens thecontrol valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected by thefirst detection unit 34. Note that the opening-closing unit 32 does not open thecontrol valve 6 positioned between the flow section where refrigerant leakage is not detected and the flow section where refrigerant leakage is detected. - The
first comparison unit 33 compares a pressure of refrigerant to a predetermined threshold. The pressure of refrigerant is measured by the indoor-side pressure sensor 21, assigned with a sensor count equal to the target count, in the flow section in which thecontrol valves 6 closed by the opening-closing unit 32 are positioned at opposite ends. The target count is a serial number representing a target indoor-side pressure sensor 21 on which the controller 9 performs processing. - The
first detection unit 34 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor 21 is determined to be lower than the predetermined threshold by thefirst comparison unit 33. - The controllers 9 accommodated in the
respective control boxes 5 cooperate with each other by communicating with each other to identify the flow section where refrigerant leaks. Further, the controllers 9 accommodated in therespective control boxes 5 cooperate with each other by communicating with each other in such a manner as to maintain thecontrol valves 6 in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected, and as to open thecontrol valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected, Note that the controllers 9 may display the location where refrigerant leaks or display information that theindoor units 2 stop operating on a remote control (not illustrated) included in theindoor units 2, a centralized controller (not illustrated) connected to theoutdoor unit 3, or other controller. -
FIG. 4 is a flowchart illustrating the operation of the controller 9 according toEmbodiment 1. With reference toFIG. 4 , the procedure for detecting the location of refrigerant leakage by thecontroller 9 a is now described. First, when the refrigerantleakage detection sensor 7 a detects refrigerant leakage, the opening-closing unit 32 in thecontroller 9 a doses the indoor-sidepipe control valves 41 a and the outdoor-sidepipe control valve 42 a (step S1). The opening-closing unit 32 in thecontroller 9 a closes the indoor-unit control valves 12 a (step S2). Further, the opening-closing unit 32 communicates with thecontroller 9 b to instruct thecontroller 9 b to close the outdoor-side pipe control valve 42 b accommodated in thecontrol box 5 b (step S3). - Next, the
first comparison unit 33 determines whether the target count exceeds the last sensor count assigned to the indoor-side pressure sensor 21 a (step S4). When the target count does not exceed the last sensor count (NO in step S4), thefirst comparison unit 33 determines whether the pressure, detected by the indoor-side pressure sensor 21 a assigned with a sensor count equal to the target count, is lower than the threshold (step S5). The pressure of refrigerant measured by the indoor-side pressure sensor 21 a is higher than the threshold (NO in step S5), the opening-closing unit 32 opens the indoor-unit control valve 12 a and the indoor-sidepipe control valve 41 a that are positioned at opposite ends of the flow section in which the indoor-side pressure sensor 21 a is provided (step S6). Thecontroller 9 a communicates with thecontroller 9 b to inform that there is no influence of refrigerant (step S7). Upon receiving the communication, thecontroller 9 b performs operation to detect the location of refrigerant leakage. As described above, in a case where a plurality of controllers 9 are provided, all the controllers 9 detect the location of refrigerant leakage. - The pressure of refrigerant measured by the indoor-
side pressure sensor 21 a is lower than the threshold (YES in step S5), thefirst detection unit 34 detects refrigerant leakage in the flow section where the indoor-side pressure sensor 21 a is provided (step S8). Further, thecontroller 9 a maintains the indoor-unit control valve 12 a and the indoor-sidepipe control valve 41 a in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected (step S9). Then, thecontroller 9 a increments the target count (step S10). - When the target count exceeds the last sensor count assigned to the indoor-
side pressure sensor 21 a (YES in step S4), thecontroller 9 a determines whether any of the indoor-sidepipe control valves 41 a is opened (step S11). When at least one of the indoor-sidepipe control valves 41 a is opened (YES in step S11), the opening-closing unit 32 opens the outdoor-sidepipe control valve 42 a (step S12). When any of the indoor-sidepipe control valves 41 a is not opened (NO in step S11), thecontroller 9 a does not change the current opened or closed state of the indoor-sidepipe control valves 41 a or the outdoor-sidepipe control valve 42 a. Thereafter, thecontroller 9 a communicates with theoutdoor unit 3 and thecontrol box 5 b to inform that detection of the location of refrigerant leakage has ended (step S13). - According to
Embodiment 1, the controller 9 compares the pressure of refrigerant measured by each of the indoor-side pressure sensors 21 to a predetermined threshold in the flow section in which the indoor-unit control valve 12 and the indoor-sidepipe control valve 41 are positioned at opposite ends. In general, when refrigerant leaks from a refrigerant pipe, the pressure of refrigerant flowing through the refrigerant pipe decreases. As described above, the controller 9 compares the pressure of refrigerant measured by the indoor-side pressure sensor 21 to the predetermined threshold. Due to this operation, the controller 9 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the indoor-side pressure sensor 21 is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system 1 can locate where refrigerant leaks in therefrigerant pipe 4. - According to
Embodiment 1, the controller 9 opens thecontrol valves 6 positioned at opposite ends of the flow section where refrigerant leakage is not detected. Thus, refrigerant flows through the flow section of therefrigerant pipe 4 where refrigerant does not leak. Therefore, the air-conditioning system 1 can continue running by using therefrigerant pipe 4 excluding the flow section where refrigerant leaks. - Further, according to
Embodiment 1, the air-conditioning system 1 includes thecontrol boxes 5. In thecontrol boxes 5, thebranch portions 11, thepipe control valves 13, and the controllers 9 are accommodated. In general, in a case where the air-conditioning system 1 is installed in a building or other space, management of thepipe control valves 13 and the controllers 9 is complicated. As described inEmbodiment 1, thebranch portions 11 thepipe control valves 13, and the controllers 9 are accommodated in thecorresponding control boxes 5, so that thebranch portions 11 thecontrol valves 6, and the controllers 9 are managed based on eachcontrol box 5. Therefore, the air-conditioning system 1 improves the ease of maintenance, and can immediately deal with refrigerant leakage to thereby minimize the influence of refrigerant leakage. - According to
Embodiment 1, when the refrigerant leakage detection sensor 7 detects refrigerant leaking from therefrigerant pipe 4, thepressure sensor 8 measures the pressure of refrigerant. Due to this operation, the air-conditioning system 1 can immediately locate where refrigerant leaks in therefrigerant pipe 4. Therefore, the air-conditioning system 1 can immediately deal with the refrigerant leakage to thereby minimize the influence of refrigerant leakage. - Further, according to
Embodiment 1, the controller 9 maintains thecontrol valves 6 in a closed state, which are positioned at opposite ends of the flow section where refrigerant leakage is detected. This prevents refrigerant from flowing to the flow section where refrigerant leakage is detected. Therefore, further refrigerant leakage can be prevented after thecontrol valves 6 are closed. - When one of the controllers 9 receives communication from the other of the controllers 9, the one of the controllers 9 controls a plurality of the
control valves 6 connected to the one of the controllers 9. Thus, a plurality of controllers 9 cooperating with each other by communicating with each other make a comparison of the pressure of refrigerant in the flow sections to the threshold in turn. Therefore, the air-conditioning system 1 can efficiently locate where refrigerant leaks in therefrigerant pipe 4 in its entirety. - According to
Embodiment 1, the controller 9 may set a predetermined time interval at which thepressure sensor 8 measures the pressure of refrigerant. Due to this operation, the air-conditioning system 1 can automatically perform regular maintenance. Therefore, the air-conditioning system 1 can reduce the maintenance load. For example, in a case where the air-conditioning system 1 uses refrigerant with a high level of safety such as a flammable refrigerant, the air-conditioning system 1 can omit the refrigerant leakage detection sensor 7. In this case, the air-conditioning system 1 can reduce the number of facilities needed, and can improve the design flexibility. -
FIG. 5 is a circuit diagram illustrating an air-conditioning system 101 according toEmbodiment 2.FIG. 6 is a functional block diagram illustrating acontroller 109 according toEmbodiment 2. Thepresent Embodiment 2 is different fromEmbodiment 1 in that theoutdoor unit 3 is provided with an outdoor-unit control valve 14. In thepresent Embodiment 2, the same components as those inEmbodiment 1 are denoted by the same reference signs, and thus descriptions thereof are omitted. The differences fromEmbodiment 1 are mainly described below. - As illustrated in
FIG. 5 , thecontrol valve 6 includes the outdoor-unit control valve 14. The outdoor-unit control valve 14 is provided in theoutdoor unit 3 to control a flow of refrigerant. An outdoor-side pressure sensor 22 is provided between the outdoor-unit control valve 14 and the outdoor-sidepipe control valve 42 to measure the pressure of refrigerant flowing through therefrigerant pipe 4. - As illustrated in
FIG. 6 , thecontroller 109 includes asecond comparison unit 133, and asecond detection unit 134. Thesecond comparison unit 133 and thesecond detection unit 134 are made up of algorithms. - The
second comparison unit 133 compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to a predetermined threshold in a plurality of flow sections dosed by the opening-closing unit 32. - The
second detection unit 134 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the outdoor-side pressure sensor 22 is determined to be lower than the predetermined threshold by the comparison unit. - According to
Embodiment 2, a controller 109 a compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to a predetermined threshold in the flow section in which the outdoor-unit control valve 14 and the outdoor-sidepipe control valve 42 are positioned at opposite ends. In general, when refrigerant leaks from therefrigerant pipe 4, the pressure of refrigerant flowing through therefrigerant pipe 4 decreases. As described above, thecontroller 109 compares the pressure of refrigerant measured by the outdoor-side pressure sensor 22 to the predetermined threshold. Due to this operation, thecontroller 109 detects refrigerant leaking in the flow section where the pressure of refrigerant measured by the outdoor-side pressure sensor 22 is determined to be lower than the predetermined threshold. Therefore, the air-conditioning system 101 can still detect refrigerant leaking even in therefrigerant pipe 4 connecting to theoutdoor unit 3 and to thecontrol box 5. -
FIG. 7 is a circuit diagram illustrating an air-conditioning system 201 according toEmbodiment 3. Thepresent Embodiment 3 is different fromEmbodiment 1 in that the air-conditioning system 201 includes a backup pipe 204. In thepresent Embodiment 3, the same components as those inEmbodiment 1 andEmbodiment 2 are denoted by the same reference signs, and thus descriptions thereof are omitted. - The differences from
Embodiment 1 andEmbodiment 2 are mainly described below. - As illustrated in
FIG. 6 , theoutdoor unit 3, thecontrol boxes 5, and theindoor unit 2 are connected by therefrigerant pipe 4 and the backup pipe 204. The backup pipe 204 runs parallel to therefrigerant pipe 4, and is used when refrigerant leakage has occurred in therefrigerant pipe 4. The backup pipe 204 is provided at a location where, for example, breakage of or other damage to a pipe is more likely to occur due to the influence exerted on the pipe by the surrounding environment such as vibrations or chemical substances. - According to
Embodiment 3, the air-conditioning system 201 includes the backup pipe 204. When refrigerant leakage has occurred in a portion of therefrigerant pipe 4, and thus a flow of the refrigerant is restricted, then the air-conditioning system 201 controls the flow of the refrigerant such that the refrigerant flows through the backup pipe 204 running parallel to therefrigerant pipe 4. Therefore, even when refrigerant leaks, the air-conditioning system 201 can still allow all theindoor units 2 to continue running. While the air-conditioning system 201 continues running, a worker can still repair the pipe. - 1: air-conditioning system, 2, 2 a, 2 b, 2 c: indoor unit, 3: outdoor unit, 4: refrigerant pipe, 5, 5 a, 5 b, 5 c: control box, 6: control valve, 7, 7 a, 7 b, 7 c: refrigerant leakage detection sensor, 8, 8 a, 8 b, 8 c: pressure sensor, 9, 9 a, 9 b, 9 c: controller, 11, 11 a, 11 b, 11 c: branch portion, 12, 12 a, 12 b, 12 c: indoor-unit control valve, 13, 13 a, 13 b, 13 c: pipe control valve, 14: outdoor-unit control valve, 21, 21 a, 21 b, 21 c: indoor-side pressure sensor, 22: outdoor-side pressure sensor, 31: communication line, 32: opening-closing unit, 33: first comparison unit, 34: first detection unit, 41, 41 a, 41 b, 41 c: indoor-side pipe control valve, 42, 42 a, 42 b, 42 c: outdoor-side pipe control valve, 101: air-conditioning system, 109: controller, 133: second comparison unit, 134: second detection unit, 204: backup pipe
Claims (10)
1. An air-conditioning system comprising:
a plurality of indoor units configured to condition air in a room;
an outdoor unit configured to supply refrigerant to each of the indoor units;
a refrigerant pipe including a branch portion from which the refrigerant pipe branches off in parallel for each of the indoor units, the refrigerant pipe connecting each of the indoor units and the outdoor unit through the branch portion, the refrigerant pipe being divided into a plurality of flow sections, the refrigerant pipe being a pipe through which refrigerant flows;
a plurality of control valves provided in the refrigerant pipe such that the plurality of control valves are positioned at opposite ends of each of the flow sections, the plurality of control valves being configured to control a flow of refrigerant in the flow sections;
a plurality of pressure sensors provided on the refrigerant pipe, and configured to measure a pressure of refrigerant flowing through the refrigerant pipe; and
a controller connected to a plurality of the control valves, and configured to control a plurality of the control valves, wherein
the control valves include
indoor-unit control valves provided in a plurality of the indoor units, and
a plurality of pipe control valves provided in the refrigerant pipe,
the pipe control valves include a plurality of indoor-side pipe control valves provided between the branch portion and the indoor units,
the pressure sensors include a plurality of indoor-side pressure sensors connected to the controller and provided between the indoor-unit control valves and the indoor-side pipe control valves, and wherein
the controller
opens or closes the control valves connected to the controller,
compares a pressure of refrigerant to a predetermined threshold, the pressure of refrigerant being measured by each of the indoor-side pressure sensors, in a plurality of the flow sections where the control valves closed are positioned at opposite ends,
detects refrigerant leaking in the flow section where a pressure of refrigerant measured by each of the indoor-side pressure sensors is determined to be lower than the predetermined threshold, and
causes the pressure sensor to measure the pressure of refrigerant at a predetermined time interval so as to allow the air-conditioning system to perform regular maintenance.
2. The air-conditioning system of claim 1 , wherein
the control valves further include an outdoor-unit control valve provided in the outdoor unit,
the pipe control valves further include an outdoor-side pipe control valve provided between the branch portion and the outdoor unit,
the pressure sensors further include an outdoor-side pressure sensor connected to the controller and provided between the outdoor-unit control valve and the outdoor-side pipe control valve, and wherein
the controller
compares a pressure of refrigerant to a predetermined threshold, the pressure of refrigerant being measured by the outdoor-side pressure sensor, in the flow sections where the control valves closed are positioned at opposite ends, and
detects refrigerant leaking in the flow section where a pressure of refrigerant measured by the outdoor-side pressure sensor is determined to be lower than the predetermined threshold.
3. The air-conditioning system of claim 1 , wherein the controller opens the control valves positioned at opposite ends of the flow sections where refrigerant leakage is not detected.
4. (canceled)
5. The air-conditioning system of claim 1 , further comprising a backup pipe that is a spare pipe running parallel to the refrigerant pipe, and configured to connect the indoor units and the outdoor unit.
6. (canceled)
7. The air-conditioning system of claim 1 , further comprising a refrigerant leakage detection sensor configured to detect refrigerant leaking from the refrigerant pipe, wherein
when the refrigerant leakage detection sensor detects refrigerant leaking from the refrigerant pipe, the pressure sensors measure a pressure of refrigerant.
8. The air-conditioning system of claim 1 , wherein the controller maintains the control valves in a closed state, the control valves being positioned at opposite ends of the flow section where refrigerant leakage is detected.
9. An air-conditioning system comprising:
a plurality of indoor units configured to condition air in a room;
an outdoor unit configured to supply refrigerant to each of the indoor units;
a refrigerant pipe including a branch portion from which the refrigerant pipe branches off in parallel for each of the indoor units, the refrigerant pipe connecting each of the indoor units and the outdoor unit through the branch portion, the refrigerant pipe being divided into a plurality of flow sections, the refrigerant pipe being a pipe through which refrigerant flows;
a plurality of control valves provided in the refrigerant pipe such that the plurality of control valves are positioned at opposite ends of each of the flow sections, the plurality of control valves being configured to control a flow of refrigerant in the flow sections;
a plurality of pressure sensors provided on the refrigerant pipe, and configured to measure a pressure of refrigerant flowing through the refrigerant pipe; and
a controller connected to a plurality of the control valves, and configured to control a plurality of the control valves, wherein
the control valves include
indoor-unit control valves provided in a plurality of the indoor units, and
a plurality of pipe control valves provided in the refrigerant pipe,
the pipe control valves include a plurality of indoor-side pipe control valves provided between the branch portion and the indoor units,
the pressure sensors include a plurality of indoor-side pressure sensors connected to the controller and provided between the indoor-unit control valves and the indoor-side pipe control valves, and wherein
the controller
opens or closes the control valves connected to the controller,
compares a pressure of refrigerant to a predetermined threshold, the pressure of refrigerant being measured by each of the indoor-side pressure sensors, in a plurality of the flow sections where the control valves are positioned at opposite ends,
detects refrigerant leaking in the flow section where a pressure of refrigerant measured by each of the indoor-side pressure sensors is determined to be lower than the predetermined threshold, wherein
the controller includes a plurality of controllers, and
when one of the controllers receives communication from an other of the controllers, the one of the controllers controls a plurality of the control valves connected to the one of the controllers.
10. An air-conditioning system comprising:
a plurality of indoor units configured to condition air in a room;
an outdoor unit configured to supply refrigerant to each of the indoor units;
a refrigerant pipe including a branch portion from which the refrigerant pipe branches off in parallel for each of the indoor units, the refrigerant pipe connecting each of the indoor units and the outdoor unit through the branch portion, the refrigerant pipe being divided into a plurality of flow sections, the refrigerant pipe being a pipe through which refrigerant flows;
a plurality of control valves provided in the refrigerant pipe such that the plurality of control valves are positioned at opposite ends of each of the flow sections, the plurality of control valves being configured to control a flow of refrigerant in the flow sections;
a plurality of pressure sensors provided on the refrigerant pipe, and configured to measure a pressure of refrigerant flowing through the refrigerant pipe;
a controller connected to a plurality of the control valves, and configured to control a plurality of the control valves; and
a control box, the control box being a container configured to accommodate therein the branch portion, the pipe control valves, and the controller, wherein
the control valves include
indoor-unit control valves provided in a plurality of the indoor units, and
a plurality of pipe control valves provided in the refrigerant pipe,
the pipe control valves include a plurality of indoor-side pipe control valves provided between the branch portion and the indoor units,
the pressure sensors include a plurality of indoor-side pressure sensors connected to the controller and provided between the indoor-unit control valves and the indoor-side pipe control valves, and wherein
the controller
opens or closes the control valves connected to the controller,
compares a pressure of refrigerant to a predetermined threshold, the pressure of refrigerant being measured by each of the indoor-side pressure sensors, in a plurality of the flow sections where the control valves are positioned at opposite ends, and
detects refrigerant leaking in the flow section where a pressure of refrigerant measured by each of the indoor-side pressure sensors is determined to be lower than the predetermined threshold,
Applications Claiming Priority (1)
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PCT/JP2020/005279 WO2021161407A1 (en) | 2020-02-12 | 2020-02-12 | Air conditioning system |
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US20230096732A1 true US20230096732A1 (en) | 2023-03-30 |
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US17/780,690 Pending US20230096732A1 (en) | 2020-02-12 | 2020-02-12 | Air-conditioning system |
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US (1) | US20230096732A1 (en) |
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JP2001241697A (en) * | 2000-02-28 | 2001-09-07 | Daikin Ind Ltd | Unit for relaying refrigerant in air conditioner |
KR100432224B1 (en) * | 2002-05-01 | 2004-05-20 | 삼성전자주식회사 | Refrigerant leakage detecting method for air conditioner |
JP2005241050A (en) * | 2004-02-24 | 2005-09-08 | Mitsubishi Electric Building Techno Service Co Ltd | Air conditioning system |
JP4274984B2 (en) * | 2004-03-22 | 2009-06-10 | 大阪瓦斯株式会社 | Branching device |
JP6116491B2 (en) * | 2014-01-16 | 2017-04-19 | 三菱電機株式会社 | Branching device |
AU2016398548B2 (en) * | 2016-03-10 | 2019-09-26 | Mitsubishi Electric Corporation | Refrigeration cycle apparatus |
JP6701337B2 (en) * | 2016-07-15 | 2020-05-27 | 三菱電機株式会社 | Air conditioner |
JP6428717B2 (en) * | 2016-07-15 | 2018-11-28 | ダイキン工業株式会社 | Refrigeration system |
WO2019130383A1 (en) * | 2017-12-25 | 2019-07-04 | 三菱電機株式会社 | Air conditioning device |
CN110671768B (en) * | 2019-10-23 | 2021-07-13 | 深圳市俊安环境科技有限公司 | Control system of cold accumulation central air conditioner |
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JPWO2021161407A1 (en) | 2021-08-19 |
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