US20210131706A1 - Air conditioner and indoor unit - Google Patents
Air conditioner and indoor unit Download PDFInfo
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- US20210131706A1 US20210131706A1 US16/477,239 US201716477239A US2021131706A1 US 20210131706 A1 US20210131706 A1 US 20210131706A1 US 201716477239 A US201716477239 A US 201716477239A US 2021131706 A1 US2021131706 A1 US 2021131706A1
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- refrigerant
- indoor
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- pipe
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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
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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
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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
- F24F11/46—Improving electric energy efficiency or saving
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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
- F24F11/62—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
- F24F11/70—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
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/88—Electrical aspects, e.g. circuits
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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
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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
- F25B40/00—Subcoolers, desuperheaters or superheaters
- F25B40/02—Subcoolers
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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
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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
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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
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
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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
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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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
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using 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
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0233—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in parallel arrangements
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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
- F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
- F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
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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
- F25B2313/029—Control issues
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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
- F25B2500/221—Preventing leaks from developing
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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
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2513—Expansion 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
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2519—On-off valves
Definitions
- the present invention relates to air conditioners and indoor units, and more particularly relates to an air conditioner configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, and an indoor unit used for the air conditioner.
- An existing air conditioner is configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe.
- An example of such an air conditioner as disclosed in PTL 1 (International Publication No. 2015/029160), performs two-phase refrigerant feed of decompressing a refrigerant to be brought into a gas-liquid two-phase state in an outdoor unit and then sending the refrigerant to an indoor unit via a liquid-refrigerant connection pipe.
- the air conditioner that performs the two-phase refrigerant feed can decrease the amount of refrigerant held by the entire air conditioner by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe turns into the gas-liquid two-phase state.
- the decrease in the amount of refrigerant can decrease the influence on environment in a case where the refrigerant leaks outside the air conditioner.
- the amount of refrigerant held by the entire air conditioner is decreased to a certain degree by the two-phase refrigerant feed as disclosed in PTL 1, the decrease in the amount of refrigerant is not occasionally sufficient for the countermeasure to leakage of the refrigerant. This is because, when the refrigerant leaks from the indoor unit, the concentration of the refrigerant increases in the air-conditioning target space where the indoor unit involving leakage of the refrigerant is arranged, and the concentration may exceed its permissible value.
- a shutoff valve may be added to each of both the liquid side and gas side of the indoor unit so as to isolate the indoor unit involving leakage of the refrigerant and to reduce leakage of the refrigerant into the air-conditioning target space.
- shutoff valves to both the liquid side and gas side of the indoor unit, however, increases the cost, and further increases the size of the indoor unit if both the shutoff valves on the liquid side and gas side are arranged in the indoor unit.
- An air conditioner is an air conditioner including an outdoor unit, a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, an indoor unit, a gas-side shutoff valve, refrigerant leakage detecting means, and a control unit.
- the indoor unit is connected to the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, is arranged in an air-conditioning target space, and includes an indoor heat exchanger, an indoor expansion valve, a heat-exchange-side indoor liquid-refrigerant pipe, and a connection-side indoor liquid-refrigerant pipe.
- the indoor heat exchanger performs heat exchange between a refrigerant, which is circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and an air, which is sent to the air-conditioning target space.
- the indoor expansion valve decompresses the refrigerant.
- the heat-exchange-side indoor liquid-refrigerant pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve.
- the connection-side indoor liquid-refrigerant pipe connects the indoor expansion valve to the liquid-refrigerant connection pipe.
- the gas-side shutoff valve is connected to a gas side of the indoor heat exchanger.
- the refrigerant leakage detecting means detects leakage of the refrigerant.
- the refrigerant leakage detecting means may be a refrigerant sensor that directly detects the leaked refrigerant, or may be one that estimates the presence or amount of leaked refrigerant on the basis of the relationship between the temperature of the refrigerant in the indoor heat exchanger and the atmospheric temperature of the indoor heat exchanger.
- the indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing. A brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is provided with a coating material.
- the control unit causes the indoor expansion valve and the gas-side shutoff valve to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- shutoff valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit.
- connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe is connected to the indoor expansion valve by brazing.
- the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion.
- the refrigerant leaks from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe, the refrigerant is continuously supplied from the liquid-refrigerant connection pipe to the brazing portion although the indoor expansion valve is closed to function as the shutoff valve on the liquid side of the indoor unit.
- the refrigerant may continuously leak from the indoor unit to the air-conditioning target space.
- the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit unless such leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced.
- the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit.
- the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- connection-side indoor liquid-refrigerant pipe includes a first connection-side indoor liquid-refrigerant pipe connected to the indoor expansion valve, a second connection-side indoor liquid-refrigerant pipe connected to the liquid-refrigerant connection pipe, and a filter that is connected between the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe.
- the filter is connected to the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe by brazing. Brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe each are provided with a coating material.
- a filter may be provided to reduce inflow of foreign substances and so forth into the connection-side indoor liquid-refrigerant pipe and the indoor expansion valve.
- the filter is also connected to the connection-side indoor liquid-refrigerant pipe (the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe) by brazing. Due to this, the brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portions.
- the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit, like the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe (the first connection-side indoor liquid-refrigerant pipe).
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- the outdoor unit includes an outdoor heat exchanger and a liquid-pressure adjustment expansion valve.
- the control unit controls the liquid-pressure adjustment expansion valve to decompress the refrigerant flowing through the liquid-refrigerant connection pipe to be brought into a gas-liquid two-phase state, and controls the indoor expansion valve to decompress the refrigerant decompressed by the liquid-pressure adjustment expansion valve.
- the outdoor unit includes the liquid-pressure adjustment expansion valve as described above, the two-phase refrigerant feed of decompressing the refrigerant to be brought into the gas-liquid two-phase state in the outdoor unit and then sending the refrigerant to the indoor unit via the liquid-refrigerant connection pipe can be performed.
- the amount of refrigerant held by the entire air conditioner can be decreased by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe turns into the gas-liquid two-phase state through the two-phase refrigerant feed.
- the amount of refrigerant held by the entire air conditioner can be decreased by a certain degree through the two-phase refrigerant feed, when the refrigerant leaks from the indoor unit, the concentration of the refrigerant increases in the air-conditioning target space where the indoor unit involving leakage of the refrigerant is arranged, and the concentration may exceed its permissible value. In such a case, the two-phase refrigerant feed is not occasionally sufficient for the countermeasure to leakage of the refrigerant.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- the addition of the refrigerant shutoff function makes the countermeasure to leakage of the refrigerant sufficient.
- the indoor unit includes a plurality of the indoor units, and the gas-side shutoff valve is provided to correspond to each of the indoor units.
- the plurality of indoor units and the plurality of gas-side shutoff valves are provided as described above. Even with this configuration, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units can be added while the increase in the cost and the sizes of the indoor units due to the provision of the shutoff valves on the liquid sides of the indoor units is reduced as much as possible.
- control unit causes only the indoor expansion valve and the gas-side shutoff valve corresponding to the indoor unit in which the refrigerant leaks among the plurality of indoor units to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- the indoor unit in which the refrigerant does not leak can continue the operation.
- the gas-refrigerant connection pipe is provided with an external shutoff valve unit including the gas-side shutoff valve.
- the gas-side shutoff valve is arranged outside the indoor unit as described above, the increase in the size of the indoor unit can be suppressed.
- the gas-side shutoff valve is connected, by brazing, to an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit, and an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit.
- a brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is also provided with a coating material.
- the gas-side shutoff valve is connected to the gas connection pipe connected to the gas-refrigerant connection pipe (the indoor-side gas connection pipe and the outdoor-side gas connection pipe) by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe may corrode and the refrigerant may leak from the corroding portion.
- the refrigerant when the external shutoff valve unit is arranged in the air-conditioning target space together with the indoor unit, if the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed, and the refrigerant may continuously leak from the external shutoff valve unit to the air-conditioning target space.
- it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe.
- the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is reduced, and the external shutoff valve unit can be arranged in the air-conditioning target space together with the indoor unit.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- the gas-refrigerant connection pipe is provided with a relay unit including a cooling/heating switching valve that individually switches corresponding one of the plurality of indoor heat exchangers to function as an evaporator or a radiator of the refrigerant.
- the control unit causes the indoor expansion valve and the cooling/heating switching valve serving as the gas-side shutoff valve to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- the cooling/heating switching valve of the relay unit used for individually switching the operating state of corresponding one of the indoor units (that is, the state in which the indoor heat exchanger functions as the evaporator of the refrigerant and the state in which the indoor heat exchanger functions as the radiator of the refrigerant) is used also as the gas-side shutoff valve.
- the cooling/heating switching valve can be used also as the shutoff valve on the gas side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the gas side of the indoor unit is reduced as much as possible.
- the cooling/heating switching valve is connected, by brazing, to an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit, and an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit.
- a brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is also provided with a coating material.
- the cooling/heating switching valve is connected to the gas connection pipe connected to the gas-refrigerant connection pipe (the indoor-side gas connection pipe and the outdoor-side gas connection pipe) by brazing. Due to this, when the relay unit is arranged in the air-conditioning target space together with the indoor unit, the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe may corrode and the refrigerant may leak from the corroding portion.
- the relay unit when the relay unit is arranged in the air-conditioning target space together with the indoor unit, if the refrigerant leaks from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the cooling/heating switching valve is closed, and the refrigerant may continuously leak from the relay unit to the air-conditioning target space.
- it is required to reduce leakage of the refrigerant from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe.
- the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is reduced, and the relay unit can be arranged in the air-conditioning target space together with the indoor unit.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- the gas-side shutoff valve is provided in the indoor unit.
- the indoor unit includes a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve, and a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe.
- the gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing.
- a brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is also provided with a coating material.
- the indoor expansion valve of the indoor unit may be used also as the liquid-side shutoff valve, and the gas-side shutoff valve may be provided at the indoor unit.
- the connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe is connected to the gas-side shutoff valve by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion.
- the refrigerant When the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed.
- the refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
- the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is reduced.
- the shutoff valve provided in the indoor unit is provided on only the gas side, and the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- An indoor unit is an indoor unit connected to an outdoor unit via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, arranged in an air-conditioning target space, and including an indoor heat exchanger, an indoor expansion valve, a heat-exchange-side indoor liquid-refrigerant pipe, and a connection-side indoor liquid-refrigerant pipe.
- the indoor heat exchanger performs heat exchange between a refrigerant, which is circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and an air, which is sent to the air-conditioning target space.
- the indoor expansion valve decompresses the refrigerant.
- the heat-exchange-side indoor liquid-refrigerant pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve.
- the connection-side indoor liquid-refrigerant pipe connects the indoor expansion valve to the liquid-refrigerant connection pipe.
- the indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing.
- a brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is provided with a coating material.
- shutoff valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit.
- connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe is connected to the indoor expansion valve by brazing.
- the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion.
- the refrigerant leaks from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe, the refrigerant is continuously supplied from the liquid-refrigerant connection pipe to the brazing portion although the indoor expansion valve is closed to function as the shutoff valve on the liquid side of the indoor unit.
- the refrigerant may continuously leak from the indoor unit to the air-conditioning target space.
- the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit unless such leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced.
- the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit.
- the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- An indoor unit further includes a gas-side shutoff valve that is connected to a gas side of the indoor heat exchanger; a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve; and a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe.
- the gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing.
- a brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is also provided with a coating material.
- the indoor expansion valve of the indoor unit may be used also as the liquid-side shutoff valve, and the gas-side shutoff valve may be provided at the indoor unit.
- the connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe is connected to the gas-side shutoff valve by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion.
- the refrigerant When the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed.
- the refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
- the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is reduced.
- the shutoff valve provided in the indoor unit is provided on only the gas side, and the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added.
- any material can be employed as long as the material can suppress corrosion of the brazing portion.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- FIG. 1 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention.
- FIG. 2 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting the air conditioner according to one or more embodiments of the present invention.
- FIG. 3 is a flowchart of an operation when a refrigerant leaks in the air conditioner according to one or more embodiments of the present invention.
- FIG. 4 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting an air conditioner according to one or more embodiments of the present invention.
- FIG. 5 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting an air conditioner according to one or more embodiments of the present invention.
- FIG. 6 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention.
- FIG. 7 illustrates a refrigerant system in the periphery of an indoor unit constituting the air conditioner according to one or more embodiments of the present invention.
- FIG. 8 is a flowchart of an operation when a refrigerant leaks in an air conditioner according to one or more embodiments of the present invention.
- FIG. 9 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention.
- FIG. 10 illustrates a refrigerant system in the periphery of an indoor unit and a relay unit constituting the air conditioner according to one or more embodiments of the present invention.
- FIG. 12 illustrates a refrigerant system in the periphery of an indoor unit and a relay unit constituting an air conditioner according to one or more embodiments of the present invention.
- FIG. 14 is a flowchart of an operation when a refrigerant leaks in an air conditioner according to one or more embodiments of the present invention.
- FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to one or more embodiments of the present invention.
- FIG. 2 illustrates a refrigerant system in the periphery of indoor units 3 a and 3 b and external shutoff valve units 4 a and 4 b constituting the air conditioner 1 according to one or more embodiments of the present invention.
- the air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air-conditioning target space in a building or the like through a vapor compression refrigeration cycle.
- the air conditioner 1 mainly includes an outdoor unit 2 ; a plurality of (in this case, two) indoor units 3 a and 3 b mutually connected in parallel; a liquid-refrigerant connection pipe 5 and a gas-refrigerant connection pipe 6 that connect the outdoor unit 2 to the indoor units 3 a and 3 b; a plurality of (in this case, two) external shutoff valve units 4 a and 4 b provided at the gas-refrigerant connection pipe 5 ; and a control unit 19 that controls components of the outdoor unit 2 , the indoor units 3 a and 3 b, and the external shutoff valve units 4 a and 4 b.
- a vapor compression refrigerant circuit 10 of the air conditioner 1 is constituted by connecting the outdoor unit 2 , the plurality of indoor units 3 a and 3 b, and the plurality of external shutoff valve units 4 a and 4 b to one another via the liquid-refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6 .
- the refrigerant circuit 10 is filled with a refrigerant such as R32.
- the liquid-refrigerant connection pipe 5 mainly includes a joint pipe portion extending from the outdoor unit 2 , and branch pipe portions 5 a and 5 b branched at a position before the indoor units 3 a and 3 b into a plurality of (in this case, two) pipe portions.
- the gas-refrigerant connection pipe 6 mainly includes a joint pipe portion extending from the outdoor unit 2 , first branch pipe portions 6 a and 6 b branched at a position before the indoor units 3 a and 3 b into a plurality of (in this case, two) pipe portions, and second branch pipe portions 6 aa and 6 bb that connect the external shutoff valve units 4 a and 4 b to the indoor units 3 a and 3 b.
- the indoor units 3 a and 3 b are arranged in air-conditioning target spaces in a building or the like. Being “arranged in air-conditioning target spaces” includes a situation in which the indoor units 3 a and 3 b are installed in the air-conditioning target spaces and a situation in which the indoor units 3 a and 3 b are not arranged in the air-conditioning target spaces but the indoor units 3 a and 3 b are connected to the air-conditioning target spaces via air ducts or the like.
- the indoor units 3 a and 3 b are connected to the outdoor unit 2 via the liquid-refrigerant connection pipe 5 , the gas-refrigerant connection pipe 6 , and the external shutoff valve units 4 a and 4 b, and constitute part of the refrigerant circuit 10 as described above.
- the indoor unit 3 a and the indoor unit 3 b have configurations similar to each other. Hence only the configuration of the indoor unit 3 a is described.
- the description of the components of the indoor unit 3 b is omitted while an index “b” is applied to each component instead of the index “a” indicating each component of the indoor unit 3 a.
- the indoor unit 3 a mainly includes an indoor expansion valve 51 a and an indoor heat exchanger 52 a.
- the indoor unit 3 a includes an indoor liquid-refrigerant pipe 53 a that connects the liquid side of the indoor heat exchanger 52 a to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ), and an indoor gas-refrigerant pipe 54 a that connects the gas side of the indoor heat exchanger 52 a to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ).
- the indoor expansion valve 51 a is an electric expansion valve that decompresses the refrigerant.
- the indoor expansion valve 51 a is provided in the indoor liquid-refrigerant pipe 53 a.
- the indoor heat exchanger 52 a is a heat exchanger that performs heat exchange between the refrigerant, which is circulated between the indoor unit 3 a and the outdoor unit 2 via the liquid-refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6 , and the indoor air, which is sent to the air-conditioning target space.
- the indoor unit 3 a includes an indoor fan 55 a that sucks the indoor air into the indoor unit 3 a, that causes the indoor air to exchange heat with the refrigerant in the indoor heat exchanger 52 a, and then that sends the indoor air into the air-conditioning target space.
- the indoor unit 3 a includes the indoor fan 55 a as a fan that sends the indoor air, which serves as a cooling source or a heating source of the refrigerant flowing through the indoor heat exchanger 52 a, to the indoor heat exchanger 52 a.
- the indoor fan 55 a is driven by an indoor fan motor 56 a.
- the indoor liquid-refrigerant pipe 53 a mainly includes a heat-exchange-side indoor liquid-refrigerant pipe 71 a that connects the liquid side of the indoor heat exchanger 52 a to the indoor expansion valve 51 a, and a connection-side indoor liquid-refrigerant pipe 72 a that connects the indoor expansion valve 51 a to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ).
- the liquid side of the indoor heat exchanger 52 a is connected to the heat-exchange-side indoor liquid-refrigerant pipe 71 a by brazing.
- the heat-exchange-side indoor liquid-refrigerant pipe 71 a is connected to the indoor expansion valve 51 a by brazing (the brazing portion is referred to as brazing portion 81 a ).
- the indoor expansion valve 51 a is connected to the connection-side indoor liquid-refrigerant pipe 72 a by brazing (the brazing portion is referred to as brazing portion 82 a ).
- the connection-side indoor liquid-refrigerant pipe 72 a is connected to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 83 a ).
- the pipe joint portion 83 a is connected to the connection-side indoor liquid-refrigerant pipe 72 a by brazing (the brazing portion is referred to as brazing portion 83 aa ).
- the connection-side indoor liquid-refrigerant pipe 72 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ) by brazing without the mechanical pipe joint such as the pipe joint portion 83 a.
- the brazing portion 82 a brazing the indoor expansion valve 51 a and the connection-side indoor liquid-refrigerant pipe 72 a is provided with a coating material 11 a .
- a coating material 11 a any material can be employed as long as the material can suppress corrosion of the brazing portion 82 a.
- a coating material made of resin can be employed.
- a water-repellent material and a heat-insulating material are suitable.
- urethane resin can be employed.
- the coating material 11 a may be provided at the brazing portion 82 a, or may be also provided at a portion other than the brazing portion 82 a. For example, as illustrated in FIG.
- the coating material 11 a may be provided in a range from the indoor expansion valve 51 a to the pipe joint portion 83 a of the connection-side indoor liquid-refrigerant pipe 72 a (that is, so as to include the brazing portion 82 a and the brazing portion 83 aa ).
- the coating material 11 a may be provided in a range from the indoor expansion valve 51 a to the brazing portion brazing the connection-side indoor liquid-refrigerant pipe 72 a and the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ).
- the gas side of the indoor heat exchanger 52 a is connected to the indoor gas-refrigerant pipe 54 a by brazing.
- the indoor gas-refrigerant pipe 54 a is connected to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 84 a ).
- the pipe joint portion 84 a is connected to the indoor gas-refrigerant pipe 54 a by brazing (the brazing portion is referred to as brazing portion 84 aa ).
- the indoor gas-refrigerant pipe 54 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ) by brazing.
- the indoor unit 3 a is provided with a refrigerant sensor 57 a serving as refrigerant leakage detecting means for detecting leakage of the refrigerant.
- the refrigerant sensor 57 a is provided in the indoor unit 3 a in this case; however, it is not limited thereto.
- the refrigerant sensor 57 a may be provided, for example, at a remote controller for operating the indoor unit 3 a, or in the air-conditioning target space where the indoor unit 3 a is arranged.
- the refrigerant leakage detecting means may be the refrigerant sensor 57 a that directly detects the leaked refrigerant as described above, or alternatively, although it is not employed in this case, the refrigerant leakage detecting means may be one that estimates the presence or amount of leaked refrigerant on the basis of the relationship between the temperature of the refrigerant in the indoor heat exchanger 52 a and the atmospheric temperature of the indoor heat exchanger 52 a.
- the outdoor unit 2 is arranged outside the air-conditioning target space or outside the building or the like.
- the outdoor unit 2 is connected to the indoor units 3 a and 3 b via the liquid-refrigerant connection pipe 5 , the gas-refrigerant connection pipe 6 , and the external shutoff valve units 4 a and 4 b, and constitutes part of the refrigerant circuit 10 as described above.
- the outdoor unit 2 mainly includes a compressor 21 and an outdoor heat exchanger 23 .
- the outdoor unit 2 includes a switching mechanism 22 that switches the operating state between a radiation operating state in which the outdoor heat exchanger 23 functions as a radiator of the refrigerant, and an evaporation operating state in which the outdoor heat exchanger 23 functions as an evaporator of the refrigerant.
- the switching mechanism 22 is connected to the suction side of the compressor 21 via a suction refrigerant pipe 31 .
- the discharge side of the compressor 21 is connected to the switching mechanism 22 via a discharge refrigerant pipe 32 .
- the switching mechanism 22 is connected to the gas side of the outdoor heat exchanger 23 via a first outdoor gas-refrigerant pipe 33 .
- the liquid side of the outdoor heat exchanger 23 is connected to the liquid-refrigerant connection pipe 5 via an outdoor liquid-refrigerant pipe 34 .
- the connection portion of the outdoor liquid-refrigerant pipe 34 with respect to the liquid-refrigerant connection pipe 5 is provided with a liquid-side shutoff valve 27 .
- the switching mechanism 22 is connected to the gas-refrigerant connection pipe 6 via a second outdoor gas-refrigerant pipe 35 .
- the connection portion of the second outdoor gas-refrigerant pipe 35 with respect to the gas-refrigerant connection pipe 6 is provided with a gas-side shutoff valve 28 .
- the liquid-side shutoff valve 27 and the gas-side shutoff valve 28 are valves that are manually opened and closed.
- the compressor 21 is a device for compressing the refrigerant.
- a closed-structure compressor in which a compression element (not illustrated) of positive-displacement type, such as rotary type or scroll type, is rotationally driven by a compressor motor 21 a is used.
- the switching mechanism 22 is a device that can switch the flow of the refrigerant in the refrigerant circuit 10 such that, when the outdoor heat exchanger 23 functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), the switching mechanism 22 connects the discharge side of the compressor 21 to the gas side of the outdoor heat exchanger 23 (see solid lines of the switching mechanism 22 in FIG. 1 ); and, when the outdoor heat exchanger 23 functions as the evaporator of the refrigerant (hereinafter, the situation is referred to as “outdoor evaporation state”), the switching mechanism 22 connects the suction side of the compressor 21 to the gas side of the outdoor heat exchanger 23 (see broken lines of the switching mechanism 22 in FIG. 1 ).
- the switching mechanism 22 is, for example, a four-way switching valve.
- the outdoor heat exchanger 23 is a heat exchanger that performs heat exchange between the outdoor air and the refrigerant, which is circulated between the outdoor unit 2 and the indoor units 3 a and 3 b via the liquid-refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6 .
- the outdoor unit 2 includes an outdoor fan 24 that sucks the outdoor air into the outdoor unit 2 that causes the outdoor air to exchange heat with the refrigerant in the outdoor heat exchanger 23 , and then that discharges the outdoor air to the outside. That is, the outdoor unit 2 includes the outdoor fan 24 as a fan that sends the outdoor air, which serves as a cooling source or a heating source of the refrigerant flowing through the outdoor heat exchanger 23 , to the outdoor heat exchanger 23 .
- the outdoor fan 24 is driven by an outdoor fan motor 24 a.
- the air conditioner 1 Focusing only on the compressor 21 , the outdoor heat exchanger 23 , the liquid-refrigerant connection pipe 5 , the indoor expansion valves 51 a and 51 b, the indoor heat exchangers 52 a and 52 b, and the gas-refrigerant connection pipe 6 , the air conditioner 1 performs an operation (cooling operation) of circulating the refrigerant in the order of the compressor 21 , the outdoor heat exchanger 23 , the liquid-refrigerant connection pipe 5 , the indoor expansion valves 51 a and 51 b, the indoor heat exchangers 52 a and 52 b, the gas-refrigerant connection pipe 6 , and the compressor 21 .
- the air conditioner 1 performs an operation (heating operation) of circulating the refrigerant in the order of the compressor 21 , the gas-refrigerant connection pipe 6 , the indoor heat exchangers 52 a and 52 b, the indoor expansion valves 51 a and 51 b, the liquid-refrigerant connection pipe 5 , the outdoor heat exchanger 23 , and the compressor 21 .
- the switching mechanism 22 is switched to the outdoor radiation state in cooling operation, and the switching mechanism 22 is switched to the outdoor evaporation state in heating operation.
- an outdoor expansion valve 25 and a liquid-pressure adjustment expansion valve 26 are provided in the outdoor liquid-refrigerant pipe 34 .
- the outdoor expansion valve 25 is an electric expansion valve that decompresses the refrigerant in heating operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid side of the outdoor heat exchanger 23 .
- the liquid-pressure adjustment expansion valve 26 is an electric expansion valve that decompresses the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into a gas-liquid two-phase state in cooling operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid-refrigerant connection pipe 5 . That is, the liquid-pressure adjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than the outdoor expansion valve 25 .
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a and 3 b in cooling operation.
- a refrigerant return pipe 41 is connected to the outdoor liquid-refrigerant pipe 34 , and a refrigerant cooler 45 is provided.
- the refrigerant return pipe 41 is a refrigerant pipe that branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 and sends the refrigerant to the compressor 21 .
- the refrigerant cooler 45 is a heat exchanger that cools the refrigerant flowing through a portion of the outdoor liquid-refrigerant pipe 34 nearer to the outdoor heat exchanger 23 than the liquid-pressure adjustment expansion valve 26 .
- the outdoor expansion valve 25 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the outdoor heat exchanger 23 than the refrigerant cooler 45 .
- the liquid-pressure adjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than the portion to which the refrigerant cooler 45 is connected (in this case, between the refrigerant cooler 45 and the liquid-side shutoff valve 27 ).
- the refrigerant return pipe 41 is a refrigerant pipe that sends the refrigerant branched from the outdoor liquid-refrigerant pipe 34 to the suction side of the compressor 21 .
- the refrigerant return pipe 41 mainly includes a refrigerant return inlet pipe 42 and a refrigerant return outlet pipe 43 .
- the refrigerant return inlet pipe 42 is a refrigerant pipe that branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 from a portion between the liquid side of the outdoor heat exchanger 23 and the liquid-pressure adjustment expansion valve 26 (in this case, a portion between the outdoor expansion valve 25 and the refrigerant cooler 45 ) and sends the refrigerant to the inlet of the refrigerant cooler 45 on the side of the refrigerant return pipe 41 .
- the refrigerant return inlet pipe 42 is provided with a refrigerant return expansion valve 44 that adjusts the flow rate of the refrigerant flowing through the refrigerant cooler 45 while decompressing the refrigerant flowing through the refrigerant return pipe 41 .
- the refrigerant return expansion valve 44 is an electric expansion valve.
- the refrigerant return outlet pipe 43 is a refrigerant pipe that sends the refrigerant from the outlet of the refrigerant cooler 45 on the side of the refrigerant return pipe 41 to the suction refrigerant pipe 31 .
- the refrigerant cooler 45 cools the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 by using the refrigerant flowing through the refrigerant return pipe 41 .
- the outdoor unit 2 is provided with various sensors. To be specific, the outdoor unit 2 is provided with a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21 . In addition, the outdoor unit 2 is provided with an outdoor heat-exchange liquid-side sensor 37 that detects a temperature Tol (outdoor heat-exchange outlet temperature Tol) of the refrigerant on the liquid side of the outdoor heat exchanger 23 , and is provided with a liquid-pipe temperature sensor 38 that detects a temperature (liquid-pipe temperature Tlp) of the refrigerant in a portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 .
- a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21 .
- the outdoor unit 2 is provided with an outdoor heat-exchange liquid-side sensor 37 that detects a temperature Tol (outdoor heat-exchange
- the external shutoff valve units 4 a and 4 b are arranged in the building or the like. In this case, the external shutoff valve units 4 a and 4 b are arranged outside the air-conditioning target spaces unlike the indoor units 3 a and 3 b.
- the external shutoff valve units 4 a and 4 b together with the gas-refrigerant connection pipe 6 , are provided between the indoor units 3 a and 3 b and the outdoor unit 2 , and constitute part of the refrigerant circuit 10 .
- the external shutoff valve unit 4 a and the external shutoff valve unit 4 b have configurations similar to each other. Hence only the configuration of the external shutoff valve unit 4 a is described.
- the description of the components of the external shutoff valve unit 4 b is omitted while an index “b” is applied to each component instead of the index “a” indicating each component of the external shutoff valve unit 4 a.
- the external shutoff valve unit 4 a is provided in the gas-refrigerant connection pipe 6 , and mainly includes a gas-side shutoff valve 58 a.
- the external shutoff valve unit 4 a includes a gas connection pipe 62 a that is connected to the first branch pipe portion 6 a , which is a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 , and that is connected to the second branch pipe portion 6 aa , which is a portion of the gas-refrigerant connection pipe 6 on the side of the indoor unit 3 a.
- the gas-side shutoff valve 58 a is an electric expansion valve that shuts off the flow of the refrigerant that is circulated between the indoor unit 3 a and the outdoor unit 2 via the gas-refrigerant connection pipe 6 .
- the gas-side shutoff valve 58 a is provided in the gas connection pipe 62 a. That is, the gas-side shutoff valve 58 a is connected to the gas side of the indoor heat exchanger 52 a via the indoor gas-refrigerant pipe 54 a of the indoor unit 3 a, the second branch pipe portion 6 aa of the gas-refrigerant connection pipe 6 , and the gas connection pipe 62 a of the external shutoff valve unit 4 a.
- the gas-side shutoff valve 58 a may not be an electric expansion valve and may be an electromagnetic valve.
- the gas connection pipe 62 a mainly includes an indoor-side gas connection pipe 66 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the indoor unit 3 a (in this case, the second branch pipe portion 6 aa ), and an outdoor-side gas connection pipe 67 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the first branch pipe portion 6 a ).
- the gas-side shutoff valve 58 a is connected to the indoor-side gas connection pipe 66 a by brazing (the brazing portion is referred to as brazing portion 91 a ).
- the gas-side shutoff valve 58 a is connected to the outdoor-side gas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 92 a ).
- the indoor-side gas connection pipe 66 a is connected to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 95 a ).
- the pipe joint portion 95 a is connected to the indoor-side gas connection pipe 66 a by brazing (the brazing portion is referred to as brazing portion 95 aa ).
- the indoor-side gas connection pipe 66 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ) by brazing.
- the outdoor-side gas connection pipe 67 a is connected to the gas-refrigerant connection pipe 6 (in this case, the first branch pipe portion 6 a ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 96 a ).
- the pipe joint portion 96 a is connected to the outdoor-side gas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 96 aa ).
- the outdoor-side gas connection pipe 67 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the first branch pipe portion 6 a ) by brazing.
- the control unit 19 is constituted by being connected to control boards or the like (not illustrated) provided in, for example, the outdoor unit 2 and the indoor units 3 a and 3 b to communicate therewith. In FIG. 1 , however, the control unit 19 is illustrated at a position separated from the outdoor unit 2 , the indoor units 3 a and 3 b, and the external shutoff valve units 4 a and 4 b for the convenience of illustration.
- the control unit 19 controls the components 21 , 22 , 24 , 25 , 26 , 44 , 51 a, 51 b, 55 a, 55 b, 58 a, and 58 b of the air conditioner 1 (in this case, the outdoor unit 2 , the indoor units 3 a and 3 b, and the external shutoff valve units 4 a and 4 b ), that is, controls the entire operation of the air conditioner 1 in accordance with the detection signals of the above-described various sensors 36 , 37 , 38 , 57 a, and 57 b.
- the operation of the air conditioner 1 when the refrigerant does not leak is described next with reference to FIG. 1 .
- the air conditioner 1 performs cooling operation and heating operation.
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 provided in the outdoor liquid-refrigerant pipe 34 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a and 3 b in cooling operation.
- the operation of the air conditioner 1 which is described below is performed by the control unit 19 that controls the components of the air conditioner 1 .
- cooling operation for example, when all the indoor units 3 a and 3 b perform cooling operation (that is, operation in which all the indoor heat exchangers 52 a and 52 b function as the evaporators of the refrigerant and the outdoor heat exchanger 23 functions as the radiator of the refrigerant), the switching mechanism 22 is switched to the outdoor radiation state (the state in which the switching mechanism 22 is indicated by solid lines in FIG. 1 ), and the compressor 21 , the outdoor fan 24 , and the indoor fans 55 a and 55 b are driven.
- the outdoor radiation state the state in which the switching mechanism 22 is indicated by solid lines in FIG. 1
- the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 via the switching mechanism 22 .
- the refrigerant sent to the outdoor heat exchanger 23 is condensed by being cooled through heat exchange with the outdoor air supplied by the outdoor fan 24 in the outdoor heat exchanger 23 that functions as the radiator of the refrigerant.
- the refrigerant flows out from the outdoor unit 2 via the outdoor expansion valve 25 , the refrigerant cooler 45 , the liquid-pressure adjustment expansion valve 26 , and the liquid-side shutoff valve 27 .
- the refrigerant flowing out from the outdoor unit 2 is branched and sent to the indoor units 3 a and 3 b via the liquid-refrigerant connection pipe 5 .
- the refrigerant sent to the indoor units 3 a and 3 b is decompressed by the indoor expansion valves 51 a and 51 b to be at low pressure.
- the refrigerant is sent to the indoor heat exchangers 52 a and 52 b.
- the refrigerant sent to the indoor heat exchangers 52 a and 52 b is evaporated by being heated through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 a and 55 b in the indoor heat exchangers 52 a and 52 b that function as the evaporators of the refrigerant.
- the refrigerant flows out from the indoor units 3 a and 3 b.
- the indoor air cooled by the indoor heat exchangers 52 a and 52 b is sent to the air-conditioning target spaces and the air-conditioning target spaces are cooled by using the cooled indoor air.
- the refrigerant flowing out from the indoor units 3 a and 3 b is sent to the external shutoff valve units 4 a and 4 b via the second branch pipe portions 6 aa and 6 bb of the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the external shutoff valve units 4 a and 4 b passes through the gas-side shutoff valves 58 a and 58 b and then flows out from the external shutoff valve units 4 a and 4 b.
- the refrigerant flowing out from the external shutoff valve units 4 a and 4 b is joined at the gas-refrigerant connection pipe 6 and sent to the outdoor unit 2 .
- the refrigerant sent to the outdoor unit 2 is sucked into the compressor 21 via the gas-side shutoff valve 28 and the switching mechanism 22 .
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a and 3 b.
- the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 , so that the two-phase refrigerant feed can be properly performed.
- the control unit 19 causes the liquid-pressure adjustment expansion valve 26 to decompress the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into the gas-liquid two-phase state.
- the refrigerant decompressed by the liquid-pressure adjustment expansion valve 26 is the refrigerant at medium pressure that is lower than the pressure of the high-pressure refrigerant and higher than the pressure of the low-pressure refrigerant.
- the control unit 19 controls the opening degree of the liquid-pressure adjustment expansion valve 26 so that a degree of subcooling SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 becomes a target degree of subcooling SCot.
- control unit 19 obtains the degree of subcooling SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 from the outdoor heat-exchange liquid-side temperature Tol.
- the control unit 19 obtains the degree of subcooling SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 by subtracting the outdoor heat-exchange outlet temperature Tol from a temperature Toc of the refrigerant, which is obtained by converting the discharge pressure Pd into a saturation temperature.
- the control unit 19 performs control to increase the opening degree of the liquid-pressure adjustment expansion valve 26 if the degree of subcooling SCo is larger than the target degree of subcooling SCot, and performs control to decrease the opening degree of the liquid-pressure adjustment expansion valve 26 if the degree of subcooling SCo is smaller than the target degree of subcooling SCot. At this time, the control unit 19 performs control to fix the opening degree of the outdoor expansion valve 25 to a fully opened state.
- the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into the gas-liquid two-phase state.
- the liquid-refrigerant connection pipe 5 is less likely filled with the refrigerant in the liquid state as compared with the case where the refrigerant flowing through the liquid-refrigerant connection pipe 5 is in the liquid state.
- the amount of refrigerant existing in the liquid-refrigerant connection pipe 5 can be decreased by that amount.
- the control unit 19 causes the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 to be constant by cooling the refrigerant flowing through the portion of the outdoor liquid-refrigerant pipe 34 nearer to the outdoor heat exchanger 23 than the liquid-pressure adjustment expansion valve 26 by the refrigerant cooler 45 by using the refrigerant flowing through the refrigerant return pipe 41 .
- the control unit 19 controls the opening degree of the refrigerant return expansion valve 44 so that the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 becomes a target liquid-pipe temperature Tlpt.
- the control unit 19 performs control to increase the opening degree of the refrigerant return expansion valve 44 if the liquid-pipe temperature Tlp is higher than the target liquid-pipe temperature Tlpt, and performs control to decrease the opening degree of the refrigerant return expansion valve 44 if the liquid-pipe temperature Tlp is lower than the target liquid-pipe temperature Tlpt.
- the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 can be maintained constant at the target liquid-pipe temperature Tlpt.
- the liquid-pipe temperature Tlp constant and reducing variation, the refrigerant flowing through the liquid-refrigerant connection pipe 5 after decompressed by the liquid-pressure adjustment expansion valve 26 can be reliably maintained in a desirable gas-liquid two-phase state.
- heating operation for example, when all the indoor units 3 a and 3 b perform heating operation (that is, operation in which all the indoor heat exchangers 52 a and 52 b function as the radiators of the refrigerant and the outdoor heat exchanger 23 functions as the evaporator of the refrigerant), the switching mechanism 22 is switched to the outdoor evaporation state (the state in which the switching mechanism 22 is indicated by broken lines in FIG. 1 ), and the compressor 21 , the outdoor fan 24 , and the indoor fans 55 a and 55 b are driven.
- heating operation that is, operation in which all the indoor heat exchangers 52 a and 52 b function as the radiators of the refrigerant and the outdoor heat exchanger 23 functions as the evaporator of the refrigerant
- the switching mechanism 22 is switched to the outdoor evaporation state (the state in which the switching mechanism 22 is indicated by broken lines in FIG. 1 ), and the compressor 21 , the outdoor fan 24 , and the indoor fans 55 a and 55 b are driven.
- the high-pressure refrigerant discharged from the compressor 21 flows out from the outdoor unit 2 via the switching mechanism 22 and the gas-side shutoff valve 28 .
- the refrigerant flowing out from the outdoor unit 2 is branched and sent to the external shutoff valve units 4 a and 4 b via the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the external shutoff valve units 4 a and 4 b passes through the gas-side shutoff valves 58 a and 58 b and then flows out from the external shutoff valve units 4 a and 4 b.
- the refrigerant flowing out from the external shutoff valve units 4 a and 4 b is sent to the indoor units 3 a and 3 b via the second branch pipe portions 6 aa and 6 bb of the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the indoor units 3 a and 3 b is sent to the indoor heat exchangers 52 a and 52 b.
- the high-pressure refrigerant sent to the indoor heat exchangers 52 a and 52 b is condensed by being cooled through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 a and 55 b in the indoor heat exchangers 52 a and 52 b that function as the radiators of the refrigerant.
- the refrigerant flows out from the indoor units 3 a and 3 b via the indoor expansion valves 51 a and 51 b .
- the indoor air heated by the indoor heat exchangers 52 a and 52 b is sent to the air-conditioning target spaces and the air-conditioning target spaces are heated by using the heated indoor air.
- the refrigerant flowing out from the indoor units 3 a and 3 b is joined at the liquid-refrigerant connection pipe 5 and sent to the outdoor unit 2 .
- the refrigerant sent to the outdoor unit 2 is sent to the outdoor expansion valve 25 via the liquid-side shutoff valve 27 , the liquid-pressure adjustment expansion valve 26 , and the refrigerant cooler 45 .
- the refrigerant sent to the outdoor expansion valve 25 is decompressed by the outdoor expansion valve 25 to be at low pressure and then is sent to the outdoor heat exchanger 23 .
- the refrigerant sent to the outdoor heat exchanger 23 is evaporated by being heated through heat exchange with the outdoor air supplied by the outdoor fan 24 .
- the refrigerant is sucked into the compressor 21 via the switching mechanism 22 .
- control unit 19 performs control to fix the opening degree of the liquid-pressure adjustment expansion valve 26 to a fully opened state.
- the opening degree of the refrigerant return expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to the refrigerant return pipe 41 .
- FIG. 3 is a flowchart of an operation when a refrigerant leaks in the air conditioner 1 according to one or more embodiments of the present invention.
- the operation of the air conditioner 1 when the refrigerant leaks which is described below is performed by the control unit 19 that controls the components of the air conditioner 1 (the outdoor unit 2 , the indoor units 3 a and 3 b, and the external shutoff valve units 4 a and 4 b ) like the operation when the refrigerant does not leak.
- the air conditioner 1 is provided with the refrigerant sensors 57 a and 57 b serving as the refrigerant leakage detecting means as described above.
- the refrigerant sensors 57 a and 57 b detect leakage of the refrigerant
- the indoor expansion valves 51 a and 51 b and the gas-side shutoff valves 58 a and 58 b are closed in accordance with the information of the refrigerant sensors 57 a and 57 b.
- the indoor units 3 a and 3 b can be isolated. Accordingly, the refrigerant can be inhibited from flowing from the refrigerant connection pipes 5 and 6 to the indoor units 3 a and 3 b.
- the indoor expansion valves 51 a and 51 b are used also as liquid-side shutoff valves and are closed together with the gas-side shutoff valves 58 a and 58 b, thereby providing a refrigerant shutoff function when the refrigerant leaks from the indoor units 3 a and 3 b.
- step ST 1 when the refrigerant sensors 57 a and 57 b detect leakage of the refrigerant (step ST 1 ), the control unit 19 closes the indoor expansion valves 51 a and 51 b and the gas-side shutoff valves 58 a and 58 b (step ST 4 ).
- step ST 2 when leakage of the refrigerant is detected in step ST 1 , an alarm may be given (step ST 2 ).
- step ST 3 the compressor 21 may be stopped (step ST 3 ) to suppress an excessive increase in the pressure of the refrigerant.
- the indoor expansion valves 51 a and 51 b and the gas-side shutoff valves 58 a and 58 b are closed in accordance with the information of the refrigerant sensors 57 a and 57 b serving as the refrigerant leakage detecting means when the refrigerant leaks.
- the refrigerant is inhibited from flowing from the refrigerant connection pipes 5 and 6 to the indoor units 3 a and 3 b, and increase in concentration of the refrigerant in the air-conditioning target spaces can be suppressed.
- the air conditioner 1 and the indoor units 3 a and 3 b have the following features.
- shutoff valves on both the liquid sides and the gas sides of the indoor units 3 a and 3 b may increase the cost and the sizes of the indoor units 3 a and 3 b.
- connection-side indoor liquid-refrigerant pipes 72 a and 72 b that connect the indoor expansion valves 51 a and 51 b to the liquid-refrigerant connection pipe 5 are connected to the indoor expansion valves 51 a and 51 b by brazing.
- the brazing portions 82 a and 82 b brazing the indoor expansion valves 51 a and 51 b and the connection-side indoor liquid-refrigerant pipes 72 a and 72 b may corrode and the refrigerant may leak from the corroding portions.
- the refrigerant When the refrigerant leaks from the brazing portions 82 a and 82 b, the refrigerant is continuously supplied from the liquid-refrigerant connection pipe 5 to the brazing portions 82 a and 82 b although the indoor expansion valves 51 a and 51 b are closed to function as the shutoff valves on the liquid sides of the indoor units 3 a and 3 b.
- the refrigerant may continuously leak from the indoor units 3 a and 3 b to the air-conditioning target spaces.
- the indoor expansion valves 51 a and 51 b can be used also as the shutoff valves on the liquid sides of the indoor units 3 a and 3 b.
- the indoor expansion valves 51 a and 51 b can be used also as the shutoff valves on the liquid sides of the indoor units 3 a and 3 b, the increase in the cost and the sizes of the indoor units 3 a and 3 b can be suppressed by that amount.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a and 3 b can be added while the increase in the cost and the sizes of the indoor units 3 a and 3 b due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a and 3 b is reduced as much as possible.
- the gas-side shutoff valves 58 a and 58 b are arranged in the external shutoff valve units 4 a and 4 b located outside the indoor units 3 a and 3 b as described above, the increase in the sizes of the indoor units 3 a and 3 b can be suppressed.
- the outdoor unit 2 includes the liquid-pressure adjustment expansion valve 26 as described above, the two-phase refrigerant feed of decompressing the refrigerant to be brought into the gas-liquid two-phase state in the outdoor unit 2 and then sending the refrigerant to the indoor units 3 a and 3 b via the liquid-refrigerant connection pipe 5 can be performed.
- the amount of refrigerant held by the entire air conditioner can be decreased by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe 5 turns into the gas-liquid two-phase state through the two-phase refrigerant feed.
- the amount of refrigerant held by the entire air conditioner can be decreased by a certain degree through the two-phase refrigerant feed, when the refrigerant leaks from the indoor units 3 a and 3 b, the concentration of the refrigerant increases in the air-conditioning target spaces where the indoor units 3 a and 3 b involving leakage of the refrigerant are arranged, and the concentration may exceed its permissible value. In such a case, the two-phase refrigerant feed is not occasionally sufficient for the countermeasure to leakage of the refrigerant.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a and 3 b can be added while the increase in the cost and the sizes of the indoor units 3 a and 3 b due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a and 3 b is reduced as much as possible.
- the addition of the refrigerant shutoff function makes the countermeasure to leakage of the refrigerant sufficient.
- only the indoor expansion valves 51 a and 51 b are provided in the indoor liquid-refrigerant pipes 53 a and 53 b as illustrated in FIG. 2 in the indoor units 3 a and 3 b arranged in the air-conditioning target spaces.
- filters 73 a and 73 b for reducing inflow of foreign substances and so forth to the indoor expansion valves 51 a and 51 b may be provided in the connection-side indoor liquid-refrigerant pipes 72 a and 72 b as illustrated in FIG. 4 in the indoor units 3 a and 3 b.
- the filters 73 a and 73 b are also connected to the connection-side indoor liquid-refrigerant pipes 72 a and 72 b by brazing.
- connection-side indoor liquid-refrigerant pipes 72 a and 72 b include first connection-side indoor liquid-refrigerant pipes 74 a and 74 b connected to the indoor expansion valves 51 a and 51 b, and second connection-side indoor liquid-refrigerant pipes 75 a and 75 b connected to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portions 5 a and 5 b ).
- the filters 73 a and 73 b are connected between the first connection-side indoor liquid-refrigerant pipes 74 a and 74 b and the second connection-side indoor liquid-refrigerant pipes 75 a and 75 b .
- the filters 73 a and 73 b are connected to the first connection-side indoor liquid-refrigerant pipes 74 a and 74 b and the second connection-side indoor liquid-refrigerant pipes 75 a and 75 b by brazing (the brazing portions are referred to as brazing portions 85 a, 85 b, 86 a, and 86 b ). Due to this, the brazing portions 85 a, 85 b, 86 a, and 86 b may corrode and the refrigerant may leak from the corroding portions.
- the brazing portions 85 a, 85 b, 86 a, and 86 b brazing the filters 73 a and 73 b with the first connection-side indoor liquid-refrigerant pipes 74 a and 74 b and the second connection-side indoor liquid-refrigerant pipes 75 a and 75 b are also provided with coating materials 11 a, 11 b, 12 a, and 12 b.
- the first connection-side indoor liquid-refrigerant pipes 74 a and 74 b including the brazing portions 82 a and 82 b and the brazing portions 85 a and 85 b are provided with the coating materials 11 a and 11 b.
- the second connection-side indoor liquid-refrigerant pipes 75 a and 75 b including the brazing portions 86 a and 86 b and the brazing portions 83 aa and 83 bb are provided with the coating materials 12 a and 12 b.
- the coating materials 12 a and 12 b may be provided to include the brazing portions brazing the second connection-side indoor liquid-refrigerant pipes 75 a and 75 b and the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ).
- a coating material may be provided at each of the brazing portions 82 a, 82 b, 85 a, 85 b, 86 a, 86 b, 83 aa , and 83 bb , or may be provided collectively at all the brazing portions 82 a, 82 b, 85 a, 85 b, 86 a, 86 b, 83 aa , and 83 bb including the filters 73 a and 73 b.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a and 3 b can be added while the increase in the cost and the sizes of the indoor units 3 a and 3 b due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a and 3 b is reduced as much as possible.
- the gas-side shutoff valves 58 a and 58 b are connected to the gas connection pipes 62 a and 62 b connected to the gas-refrigerant connection pipe 6 (the indoor-side gas connection pipes 66 a and 66 b and the outdoor-side gas connection pipes 67 a and 67 b ) by brazing. Due to this, the brazing portions 92 a and 92 b brazing the gas-side shutoff valves 58 a and 58 b and the outdoor-side gas connection pipes 67 a and 67 b may corrode and the refrigerant may leak from the corroding portions.
- the external shutoff valve units 4 a and 4 b are arranged outside the air-conditioning target spaces. Hence, even when the refrigerant leaks from the brazing portions 92 a and 92 b, the refrigerant hardly leaks to the air-conditioning target spaces.
- the brazing portions 92 a and 92 b brazing the gas-side shutoff valves 58 a and 58 b and the outdoor-side gas connection pipes 67 a and 67 b are also provided with coating materials 13 a and 13 b.
- the coating materials 13 a and 13 b may be provided at only the brazing portions 92 a and 92 b, or may be also provided at a portion other than the brazing portions 92 a and 92 b.
- FIG. 5 the brazing portions 92 a and 92 b brazing the gas-side shutoff valves 58 a and 58 b and the outdoor-side gas connection pipes 67 a and 67 b are also provided with coating materials 13 a and 13 b.
- the coating materials 13 a and 13 b may be provided at only the brazing portions 92 a and 92 b, or may be also provided at a portion other than the brazing portions 92 a and 92 b.
- the coating materials 13 a and 13 b may be provided in a range from the gas-side shutoff valves 58 a and 58 b to the pipe joint portions 96 a and 96 b of the outdoor-side gas connection pipes 67 a and 67 b (that is, so as to include the brazing portions 92 a and 92 b and the brazing portions 96 aa and 96 bb ).
- the coating materials 13 a and 13 b may be provided in a range from the gas-side shutoff valves 58 a and 58 b to the brazing portions brazing the outdoor-side gas connection pipes 67 a and 67 b and the gas-refrigerant connection pipe 6 (in this case, the first branch pipe portions 6 a and 6 b ).
- the brazing portions 92 a and 92 b brazing the gas-side shutoff valves 58 a and 58 b and the outdoor-side gas connection pipes 67 a and 67 b are provided with the coating materials 13 a and 13 b ; however, it is not limited to the above.
- the brazing portions 92 a and 92 b brazing the gas-side shutoff valves 58 a and 58 b and the outdoor-side gas connection pipes 67 a and 67 b may be provided with the coating materials 13 a and 13 b.
- the indoor expansion valves 51 a and 51 b of the indoor units 3 a and 3 b are used also as the liquid-side shutoff valves.
- the gas-side shutoff valves 58 a and 58 b are provided at the external shutoff valve units 4 a and 4 b.
- the gas-side shutoff valves 58 a and 58 b may be provided at the indoor units 3 a and 3 b as illustrated in FIG.
- the indoor gas-refrigerant pipes 54 a and 54 b mainly include heat-exchange-side indoor gas-refrigerant pipes 76 a and 76 b that connect the gas sides of the indoor heat exchangers 52 a and 52 b to the gas-side shutoff valves 58 a and 58 b, and connection-side indoor gas-refrigerant pipes 77 a and 77 b that connect the gas-side shutoff valves 58 a and 58 b to the gas-refrigerant connection pipe 6 (in this case, the branch pipe portions 6 a and 6 b ).
- the heat-exchange-side indoor gas-refrigerant pipes 76 a and 76 b are connected to the gas-side shutoff valves 58 a and 58 b by brazing (the brazing portions are referred to as brazing portions 87 a and 87 b ), and the gas-side shutoff valves 58 a and 58 b are connected to the connection-side indoor gas-refrigerant pipes 77 a and 77 b by brazing (the brazing portions are referred to as brazing portions 88 a and 88 b ).
- the brazing portions 88 a and 88 b brazing the gas-side shutoff valves 58 a and 58 b and the connection-side indoor gas-refrigerant pipes 77 a and 77 b may corrode and the refrigerant may leak from the corroding portions.
- the refrigerant leaks from the brazing portions 88 a and 88 b, the refrigerant is continuously supplied from the gas-refrigerant connection pipe 6 to the brazing portions 88 a and 88 b although the gas-side shutoff valves 58 a and 58 b are closed.
- the refrigerant may continuously leak from the indoor units 3 a and 3 b to the air-conditioning target spaces.
- the brazing portions 88 a and 88 b brazing the gas-side shutoff valves 58 a and 58 b and the connection-side indoor gas-refrigerant pipes 77 a and 77 b are provided with coating materials 15 a and 15 b.
- the coating materials 15 a and 15 b may be provided at only the brazing portions 88 a and 88 b, or may be also provided at a portion other than the brazing portions 88 a and 88 b. For example, as illustrated in FIG.
- the coating materials 15 a and 15 b may be provided in a range from the gas-side shutoff valves 58 a and 58 b to the pipe joint portions 84 a and 84 b of the connection-side indoor gas-refrigerant pipes 77 a and 77 b (that is, so as to include the brazing portions 88 a and 88 b and the brazing portions 84 aa and 84 bb ).
- the coating materials 15 a and 15 b may be provided in a range from the gas-side shutoff valves 58 a and 58 b to the brazing portions brazing the connection-side indoor gas-refrigerant pipes 77 a and 77 b and the gas-refrigerant connection pipe 6 (in this case, the branch pipe portions 6 a and 6 b ).
- the gas-side shutoff valves 58 a and 58 b are provided in the indoor units 3 a and 3 b, and the brazing portions 88 a and 88 b brazing the gas-side shutoff valves 58 a and 58 b and the connection-side indoor gas-refrigerant pipes 77 a and 77 b are provided with the coating materials 15 a and 15 b ; however, it is not limited to the above.
- the configuration of the above-described first modification see FIG.
- the gas-side shutoff valves 58 a and 58 b may be provided at the indoor unit 3 a and 3 b, and the brazing portions 88 a and 88 b brazing the gas-side shutoff valves 58 a and 58 b and the connection-side indoor gas-refrigerant pipes 77 a and 77 b may be provided with the coating materials 15 a and 15 b.
- shutoff valves provided at the indoor units 3 a and 3 b are provided on only the gas side, and the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a and 3 b can be added.
- step ST 1 when the refrigerant sensors 57 a and 57 b detect leakage of the refrigerant (step ST 1 ), the control unit 19 closes only the indoor expansion valve and the gas-side shutoff valve corresponding to the indoor unit in which the refrigerant leaks among a plurality of indoor units 3 a and 3 b (step ST 5 ). Then, by continuing the circulation of the refrigerant in the refrigerant circuit 10 without stopping the compressor 21 , the cooling operation or heating operation of the indoor unit in which the refrigerant does not leak is continued (step ST 6 ).
- the external shutoff valve units 4 a and 4 b corresponding to the indoor units 3 a and 3 b are provided.
- an external shutoff valve unit in which the external shutoff valve units 4 a and 4 b may be integrated that is, an external shutoff valve unit including both the gas-side shutoff valves 58 a and 58 b may be employed.
- FIG. 9 is a schematic configuration diagram of an air conditioner 1 according to one or more embodiments of the present invention.
- FIG. 10 illustrates a refrigerant system in the periphery of indoor units 3 a, 3 b, 3 c, and 3 d and relay units 4 a, 4 b, 4 c, and 4 d constituting the air conditioner 1 according to one or more embodiments of the present invention.
- the air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air-conditioning target space in a building or the like through a vapor compression refrigeration cycle.
- the air conditioner 1 mainly includes an outdoor unit 2 ; a plurality of (in this case, four) indoor units 3 a, 3 b, 3 c, and 3 d mutually connected in parallel; relay units 4 a, 4 b, 4 c, and 4 d respectively connected to the indoor units 3 a, 3 b, 3 c, and 3 d; a liquid-refrigerant connection pipe 5 and a gas-refrigerant connection pipe 6 that connect the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d via the relay units 4 a, 4 b, 4 c, and 4 d; and a control unit 19 that controls components of the outdoor unit 2 , the indoor units 3 a, 3 b, 3 c , and 3 d, and the relay units 4 a, 4 b
- a vapor compression refrigerant circuit 10 of the air conditioner 1 is constituted by connecting the outdoor unit 2 , the plurality of indoor units 3 a, 3 b, 3 c, and 3 d, the plurality of relay units 4 a, 4 b, 4 c, and 4 d, the liquid-refrigerant connection pipe 5 , and the gas-refrigerant connection pipe 6 .
- the refrigerant circuit 10 is filled with a refrigerant such as R32.
- the indoor units 3 a, 3 b, 3 c, and 3 d can individually perform cooling operation or heating operation by using the relay units 4 a , 4 b, 4 c, and 4 d.
- heat is recovered between the indoor units (in this case, cooling and heating mixed operation in which cooling operation and heating operation can be simultaneously performed).
- the liquid-refrigerant connection pipe 5 mainly includes a joint pipe portion extending from the outdoor unit 2 , first branch pipe portions 5 a, 5 b, 5 c, and 5 d branched at a position before the relay units 4 a, 4 b, 4 c, and 4 d into a plurality of (in this case, four) pipe portions, and second branch pipe portions 5 aa , 5 bb , 5 cc , and 5 dd that connect the relay units 4 a, 4 b, 4 c, and 4 d to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the gas-refrigerant connection pipe 6 mainly includes a high/low-pressure gas-refrigerant connection pipe 7 , a low-pressure gas-refrigerant connection pipe 8 , and branch pipe portions 6 a, 6 b, 6 c, and 6 d that connect the relay units 4 a, 4 b, 4 c, and 4 d to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the high/low-pressure gas-refrigerant connection pipe 7 is a gas-refrigerant connection pipe that can switch connection to the discharge side or the suction side of a compressor 21 (described later), and includes a joint pipe portion extending from the outdoor unit 2 , and a plurality of (in this case, four) branch pipe portions 7 a, 7 b, 7 c, and 7 d branched at a position before the relay units 4 a, 4 b, 4 c, and 4 d.
- the low-pressure gas-refrigerant connection pipe 8 is a gas-refrigerant connection pipe connected to the suction side of the compressor 21 (described later), and includes a joint pipe portion extending from the outdoor unit 2 , and branch pipe portions 8 a, 8 b, 8 c, and 8 d branched at a position before the relay units 4 a, 4 b, 4 c, and 4 d into a plurality of (in this case, four) pipe portions.
- the configuration includes three connection pipes including the liquid-refrigerant connection pipe 5 (that is, three-pipe configuration).
- the indoor units 3 a, 3 b, 3 c, and 3 d are arranged in air-conditioning target spaces in a building or the like. Being “arranged in air-conditioning target spaces” includes a situation in which the indoor units 3 a, 3 b, 3 c, and 3 d are installed in the air-conditioning target spaces and a situation in which the indoor units 3 a, 3 b, 3 c, and 3 d are not arranged in the air-conditioning target spaces but the indoor units 3 a, 3 b, 3 c, and 3 d are connected to the air-conditioning target spaces via air ducts or the like.
- the indoor units 3 a, 3 b, 3 c, and 3 d are connected to the outdoor unit 2 via the liquid-refrigerant connection pipe 5 , the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7 , the low-pressure gas-refrigerant connection pipe 8 , and the branch pipe portions 6 a, 6 b, 6 c, and 6 d ), and the relay units 4 a, 4 b , 4 c, and 4 d, and constitute part of the refrigerant circuit 10 as described above.
- the gas-refrigerant connection pipe 6 the high/low-pressure gas-refrigerant connection pipe 7 , the low-pressure gas-refrigerant connection pipe 8 , and the branch pipe portions 6 a, 6 b, 6 c, and 6 d
- the relay units 4 a, 4 b , 4 c, and 4 d constitute part of the refrigerant circuit 10 as described above.
- the indoor unit 3 a and the indoor units 3 b, 3 c, and 3 d have configurations similar to one another. Hence only the configuration of the indoor unit 3 a is described.
- the description of the components of the indoor units 3 b, 3 c, and 3 d is omitted while an index “b”, “c”, or “d” is applied to each component instead of the index “a” indicating each component of the indoor unit 3 a.
- the indoor unit 3 a mainly includes an indoor expansion valve 51 a and an indoor heat exchanger 52 a.
- the indoor unit 3 a includes an indoor liquid-refrigerant pipe 53 a that connects the liquid side of the indoor heat exchanger 52 a to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portion 5 a ), and an indoor gas-refrigerant pipe 54 a that connects the gas side of the indoor heat exchanger 52 a to the gas-refrigerant connection pipe 6 (in this case, the second branch pipe portion 6 aa ).
- the indoor expansion valve 51 a, the indoor heat exchanger 52 a, the indoor liquid-refrigerant pipe 53 a, and the indoor gas-refrigerant pipe 54 a are similar to the indoor expansion valve 51 a, the indoor heat exchanger 52 a, the indoor liquid-refrigerant pipe 53 a, and the indoor gas-refrigerant pipe 54 a of the indoor unit 3 a according to one or more embodiments. Thus, the description thereof is omitted.
- a brazing portion 82 a brazing the indoor expansion valve 51 a and a connection-side indoor liquid-refrigerant pipe 72 a is provided with a coating material 11 a, like the indoor unit 3 a according to one or more embodiments.
- the indoor unit 3 a is provided with a refrigerant sensor 57 a serving as refrigerant leakage detecting means for detecting leakage of the refrigerant, like the indoor unit 3 a according to one or more embodiments.
- the outdoor unit 2 is arranged outside the air-conditioning target spaces or outside the building or the like.
- the outdoor unit 2 is connected to the indoor units 3 a, 3 b, 3 c, and 3 d via the liquid-refrigerant connection pipe 5 , the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7 , the low-pressure gas-refrigerant connection pipe 8 , and the branch pipe portions 6 a, 6 b, 6 c, and 6 d ), and the relay units 4 a, 4 b, 4 c, and 4 d, and constitutes part of the refrigerant circuit 10 as described above.
- the gas-refrigerant connection pipe 6 the high/low-pressure gas-refrigerant connection pipe 7 , the low-pressure gas-refrigerant connection pipe 8 , and the branch pipe portions 6 a, 6 b, 6 c, and 6 d
- the outdoor unit 2 mainly includes a compressor 21 and at least one, in this case, two outdoor heat exchangers 23 a and 23 b.
- the compressor 21 is similar to the compressor 21 of the outdoor unit 2 according to one or more embodiments, and hence the description thereof is omitted.
- the outdoor unit 2 includes switching mechanisms 22 a and 22 b that switch the operating state between a radiation operating state in which the outdoor heat exchangers 23 a and 23 b function as radiators of the refrigerant, and an evaporation operating state in which the outdoor heat exchangers 23 a and 23 b function as evaporators of the refrigerant.
- the switching mechanisms 22 a and 22 b are connected to the suction side of the compressor 21 via a suction refrigerant pipe 31 .
- the discharge side of the compressor 21 is connected to the switching mechanisms 22 a and 2 b via a discharge refrigerant pipe 32 .
- the switching mechanism 22 a is connected to the gas-side ends of the outdoor heat exchangers 23 a and 23 b via first outdoor gas-refrigerant pipes 33 a and 33 b.
- the liquid sides of the outdoor heat exchangers 23 a and 23 b are connected to the liquid-refrigerant connection pipe 5 via an outdoor liquid-refrigerant pipe 34 .
- the connection portion of the outdoor liquid-refrigerant pipe 34 with respect to the liquid-refrigerant connection pipe 5 is provided with a liquid-side shutoff valve 27 .
- the outdoor unit 2 includes a third switching mechanism 22 c that switches the operating state between a refrigerant lead-out state in which the refrigerant discharged from the compressor 21 is sent to the high/low-pressure gas-refrigerant connection pipe 7 , and a refrigerant lead-in state in which the refrigerant flowing through the high/low-pressure gas-refrigerant connection pipe 7 is sent to the suction refrigerant pipe 31 .
- the third switching mechanism 22 c is connected to the high/low-pressure gas-refrigerant connection pipe 7 via a second outdoor gas-refrigerant pipe 35 .
- the third switching mechanism 22 c is connected to the suction side of the compressor 21 via the suction refrigerant pipe 31 .
- the discharge side of the compressor 21 is connected to the third switching mechanism 22 c via the discharge refrigerant pipe 32 .
- the connection portion of the second outdoor gas-refrigerant pipe 35 with respect to the high/low-pressure gas-refrigerant connection pipe 7 is provided with a high/low-pressure gas-side shutoff valve 28 a.
- the suction refrigerant pipe 31 is connected to the low-pressure gas-refrigerant connection pipe 8 .
- the connection portion of the suction refrigerant pipe 31 with respect to the low-pressure gas-refrigerant connection pipe 8 is provided with a low-pressure gas-side shutoff valve 28 b.
- the liquid-side shutoff valve 27 and the gas-side shutoff valves 28 a and 28 b are valves that are manually opened and closed.
- the first switching mechanism 22 a is a device that can switch the flow of the refrigerant in the refrigerant circuit 10 such that, when the first outdoor heat exchanger 23 a functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), the first switching mechanism 22 a connects the discharge side of the compressor 21 to the gas side of the first outdoor heat exchanger 23 a (see solid lines of the first switching mechanism 22 a in FIG.
- the first switching mechanism 22 a connects the suction side of the compressor 21 to the gas side of the first outdoor heat exchanger 23 a (see broken lines of the first switching mechanism 22 a in FIG. 9 ).
- the first switching mechanism 22 a is, for example, a four-way switching valve.
- the second switching mechanism 22 b is a device that can switch the flow of the refrigerant in the refrigerant circuit 10 such that, when the second outdoor heat exchanger 23 b functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), the second switching mechanism 22 b connects the discharge side of the compressor 21 to the gas side of the second outdoor heat exchanger 23 b (see solid lines of the second switching mechanism 22 b in FIG.
- the second switching mechanism 22 b connects the suction side of the compressor 21 to the gas side of the second outdoor heat exchanger 23 b (see broken lines of the switching mechanism 22 in FIG. 9 ).
- the second switching mechanism 22 b is, for example, a four-way switching valve.
- the first outdoor heat exchanger 23 a and the second outdoor heat exchanger 23 b are heat exchangers that exchange heat between the refrigerant, which is circulated among the outdoor unit 2 and the indoor units 3 a, 3 b, 3 c, and 3 d via the liquid-refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6 , and the outdoor air.
- the outdoor unit 2 includes an outdoor fan 24 that sucks the outdoor air into the outdoor unit 2 , that causes the outdoor air to exchange heat with the refrigerant in the outdoor heat exchangers 23 a and 23 b, and then that discharges the outdoor air to the outside.
- the outdoor unit 2 includes the outdoor fan 24 as a fan that sends the outdoor air, which serves as a cooling source or a heating source of the refrigerant flowing through the outdoor heat exchangers 23 a and 23 b, to the outdoor heat exchangers 23 a and 23 b.
- the outdoor fan 24 is driven by an outdoor fan motor 24 a.
- the third switching mechanism 22 c is a device that can switch the flow of the refrigerant in the refrigerant circuit 10 such that, when the refrigerant discharged from the compressor 21 is sent to the high/low-pressure gas-refrigerant connection pipe 7 (hereinafter, the situation is referred to as “refrigerant lead-out state”), the third switching mechanism 22 c connects the discharge side of the compressor 21 to the high/low-pressure gas-refrigerant connection pipe 7 (see broken lines of the third switching mechanism 22 c in FIG.
- the third switching mechanism 22 c connects the suction side of the compressor 21 to the high/low-pressure gas-refrigerant connection pipe 7 (see solid lines of the third switching mechanism 22 c in FIG. 9 ).
- the third switching mechanism 22 c is, for example, a four-way switching valve.
- the air conditioner 1 Focusing on the outdoor heat exchangers 23 a and 23 b, the liquid-refrigerant connection pipe 5 , the relay units 4 a, 4 b, 4 c, and 4 d, and the indoor heat exchangers 52 a, 52 b , 52 c, and 52 d, the air conditioner 1 performs an operation (cooling only operation and cooling main operation) of circulating the refrigerant from the outdoor heat exchangers 23 a and 23 b , via the liquid-refrigerant connection pipe 5 and the relay units 4 a, 4 b, 4 c, and 4 d, to the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d that function as the evaporators of the refrigerant.
- the cooling only operation is an operating state in which only the indoor heat exchangers that function as the evaporators of the refrigerant (that is, the indoor units that perform cooling operation) exist.
- the cooling main operation is an operating state in which both the indoor heat exchanger that functions as the evaporator of the refrigerant and the indoor heat exchanger that functions as the radiator of the refrigerant (that is, the indoor unit that performs heating operation) are mixed; however, the load on the evaporation side (that is, cooling load) is relatively large as a whole.
- the air conditioner 1 Focusing on the compressor 21 , the gas-refrigerant connection pipe 6 , the relay units 4 a, 4 b, 4 c, and 4 d, and the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d, the air conditioner 1 performs an operation (heating only operation and heating main operation) of circulating the refrigerant from the compressor 21 , via the gas-refrigerant connection pipe 6 and the relay units 4 a, 4 b, 4 c, and 4 d, to the indoor heat exchangers 52 a, 52 b , 52 c, and 52 d that function as the radiators of the refrigerant.
- the heating only operation is an operating state in which only the indoor heat exchangers that function as the radiators of the refrigerant (that is, the indoor units that perform heating operation) exist.
- the heating main operation is an operating state in which both the indoor heat exchanger that functions as the radiator of the refrigerant and the indoor heat exchanger that functions as the evaporator of the refrigerant are mixed; however, the load on the radiation side (that is, heating load) is relatively large as a whole.
- at least one of the switching mechanisms 22 a and 22 b is switched to the outdoor radiation state.
- the outdoor heat exchangers 23 a and 23 b function as the radiators of the refrigerant as a whole, and the refrigerant flows from the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d via the liquid-refrigerant connection pipe 5 and the relay units 4 a, 4 b, 4 c, and 4 d.
- at least one of the switching mechanisms 22 a and 22 b is switched to the outdoor evaporation state and the third switching mechanism 22 c is switched to the refrigerant lead-out state.
- the outdoor heat exchangers 23 a and 23 b function as the evaporators of the refrigerant as a whole, and the refrigerant flows from the indoor units 3 a, 3 b, 3 c, and 3 d to the outdoor unit 2 via the liquid-refrigerant connection pipe 5 and the relay units 4 a, 4 b, 4 c, and 4 d.
- outdoor expansion valves 25 a and 25 b and a liquid-pressure adjustment expansion valve 26 are provided in the outdoor liquid-refrigerant pipe 34 .
- the outdoor expansion valves 25 a and 25 b are electric expansion valves that decompress the refrigerant in heating only operation and heating main operation, and are provided in portions of the outdoor liquid-refrigerant pipe 34 near the liquid sides of the outdoor heat exchangers 23 a and 23 b .
- the liquid-pressure adjustment expansion valve 26 is an electric expansion valve that decompresses the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into a gas-liquid two-phase state in cooling only operation and cooling main operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid-refrigerant connection pipe 5 . That is, the liquid-pressure adjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than the outdoor expansion valves 25 a and 25 b.
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d in cooling only operation and cooling main operation.
- a refrigerant return pipe 41 is connected to the outdoor liquid-refrigerant pipe 34 , and a refrigerant cooler 45 is provided.
- the refrigerant return pipe 41 and the refrigerant cooler 45 are similar to the refrigerant return pipe 41 and the refrigerant cooler 45 of the outdoor unit 2 according to one or more embodiments, and hence the description thereof is omitted.
- the outdoor unit 2 is provided with various sensors. To be specific, the outdoor unit 2 is provided with a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21 . In addition, the outdoor unit 2 is provided with outdoor heat-exchange liquid-side sensors 37 a and 37 b that detect temperatures Tol (outdoor heat-exchange outlet temperatures Tol) of the refrigerant on the liquid sides of the outdoor heat exchangers 23 a and 23 b, and is provided with a liquid-pipe temperature sensor 38 that detects a temperature (liquid-pipe temperature Tlp) of the refrigerant in a portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 .
- a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21 .
- the outdoor unit 2 is provided with outdoor heat-exchange liquid-side sensors 37 a and 37 b that detect
- the relay units 4 a, 4 b, 4 c, and 4 d are arranged in the building or the like. In this case, the relay units 4 a, 4 b, 4 c, and 4 d are arranged outside the air-conditioning target spaces unlike the indoor units 3 a, 3 b, 3 c, and 3 d.
- the relay units 4 a, 4 b, 4 c, and 4 d are connected between the indoor units 3 a, 3 b, 3 c, and 3 d and the outdoor unit 2 , together with the liquid-refrigerant connection pipe 5 , the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7 , the low-pressure gas-refrigerant connection pipe 8 , and the branch pipe portions 6 a, 6 b, 6 c, and 6 d ), and constitute part of the refrigerant circuit 10 .
- Configurations of the relay units 4 a, 4 b, 4 c, and 4 d are described next.
- the relay unit 4 a and the relay units 4 b, 4 c, and 4 d have configurations similar to one another. Hence only the configuration of the relay unit 4 a is described.
- the description of the components of the relay units 4 b, 4 c, and 4 d is omitted while an index “b”, “c”, or “d” is applied to each component instead of the index “a” indicating each component of the relay unit 4 a.
- the relay unit 4 a mainly includes a liquid connection pipe 61 a and a gas connection pipe 62 a.
- One end of the liquid connection pipe 61 a is connected to the first branch pipe portion 5 a of the liquid-refrigerant connection pipe 5 .
- the other end of the liquid connection pipe 61 a is connected to the second branch pipe portion 5 aa of the liquid-refrigerant connection pipe 5 .
- the liquid connection pipe 61 a is connected to a portion of the liquid-refrigerant connection pipe 5 on the side of the indoor unit 3 a (in this case, the second branch pipe portion 5 aa ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 98 a ).
- the pipe joint portion 98 a is connected to the liquid connection pipe 61 a by brazing (the brazing portion is referred to as brazing portion 98 aa ).
- the liquid connection pipe 61 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, the second branch pipe portion 5 aa ) by brazing.
- the liquid connection pipe 61 a is connected to a portion of the liquid-refrigerant connection pipe 5 on the side of the outdoor unit 2 (in this case, the first branch pipe portion 5 a ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 99 a ).
- the pipe joint portion 99 a is connected to the liquid connection pipe 61 a by brazing (the brazing portion is referred to as brazing portion 99 aa ).
- the liquid connection pipe 61 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, the first branch pipe portion 5 a ) by brazing.
- the gas connection pipe 62 a includes a high-pressure gas connection pipe 63 a connected to the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 , a low-pressure gas connection pipe 64 a connected to the branch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 , and a joint gas connection pipe 65 a that joins the high-pressure gas connection pipe 63 a and the low-pressure gas connection pipe 64 a together.
- the joint gas connection pipe 65 a is connected to the branch pipe portion 6 a of the gas-refrigerant connection pipe 6 .
- the high-pressure gas connection pipe 63 a is provided with a first cooling/heating switching valve 58 a.
- the low-pressure gas connection pipe 64 a is provided with a second cooling/heating switching valve 59 a.
- the first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a are electric expansion valves.
- the first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a may not be electric expansion valves and may be electromagnetic valves.
- the relay unit 4 a can function such that, when the indoor unit 3 a performs cooling operation, the second cooling/heating switching valve 59 a is opened to allow the refrigerant to flow into the liquid connection pipe 61 a via the first branch pipe portion 5 a of the liquid-refrigerant connection pipe 5 , the refrigerant is sent to the indoor unit 3 a via the second branch pipe portion 5 aa of the liquid-refrigerant connection pipe 5 , then the refrigerant evaporated through heat exchange with the indoor air in the indoor heat exchanger 52 a is recovered to the branch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 via the branch pipe portion 6 a of the gas-refrigerant connection pipe 6 , the joint gas connection pipe 65 a, and the low-pressure gas connection pipe 64 a.
- the relay unit 4 a can function such that, when the indoor unit 3 a performs heating operation, the second cooling/heating switching valve 59 a is closed and the first cooling/heating switching valve 58 a is opened to allow the refrigerant to flow into the high-pressure gas connection pipe 63 a and the joint gas connection pipe 65 a via the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 , the refrigerant is sent to the indoor unit 3 a via the branch pipe portion 6 a of the gas-refrigerant connection pipe 6 , then the refrigerant radiated through heat exchange with the indoor air in the indoor heat exchanger 52 a is recovered to the first branch pipe portion 5 a of the liquid-refrigerant connection pipe 5 via the second branch pipe portion 5 aa of the liquid-refrigerant connection pipe 5 and the liquid connection pipe 61 a.
- the first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a are opened and closed through switching to cause the indoor heat exchanger 52 a to function as the evaporator of the refrigerant or the radiator of the refrigerant.
- the relay unit 4 a not only the relay unit 4 a but also the relay units 4 b, 4 c, and 4 d have such a function.
- the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d can be individually switched to function as the evaporators of the refrigerant or the radiators of the refrigerant.
- the high-pressure gas connection pipe 63 a mainly includes an indoor-side high-pressure gas connection pipe 66 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the indoor unit 3 a (in this case, the branch pipe portion 6 a ) via the joint gas connection pipe 65 a, and an outdoor-side high-pressure gas connection pipe 67 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 ).
- the first cooling/heating switching valve 58 a is connected to the indoor-side high-pressure gas connection pipe 66 a by brazing (the brazing portion is referred to as brazing portion 91 a ).
- the first cooling/heating switching valve 58 a is connected to the outdoor-side high-pressure gas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 92 a ).
- the low-pressure gas connection pipe 64 a mainly includes an indoor-side low-pressure gas connection pipe 68 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the indoor unit 3 a (in this case, the branch pipe portion 6 a ) via the joint gas connection pipe 65 a, and an outdoor-side low-pressure gas connection pipe 69 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the branch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 ).
- the second cooling/heating switching valve 59 a is connected to the indoor-side low-pressure gas connection pipe 68 a by brazing (the brazing portion is referred to as brazing portion 93 a ).
- the second cooling/heating switching valve 59 a is connected to the outdoor-side low-pressure gas connection pipe 69 a by brazing (the brazing portion is referred to as brazing portion 94 a ).
- the joint gas connection pipe 65 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the indoor unit 3 a (in this case, the branch pipe portion 6 a ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 95 a ).
- the pipe joint portion 95 a is connected to the joint gas connection pipe 65 a by brazing (the brazing portion is referred to as brazing portion 95 aa ).
- the joint gas connection pipe 65 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the branch pipe portion 6 a ) by brazing.
- the outdoor-side high-pressure gas connection pipe 67 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 96 a ).
- the pipe joint portion 96 a is connected to the outdoor-side high-pressure gas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 96 aa ).
- the brazing portion is referred to as brazing portion 96 aa .
- the outdoor-side high-pressure gas connection pipe 67 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 ) by brazing.
- the outdoor-side low-pressure gas connection pipe 69 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the branch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 ) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipe joint portion 97 a ).
- the pipe joint portion 97 a is connected to the outdoor-side low-pressure gas connection pipe 69 a by brazing (the brazing portion is referred to as brazing portion 97 aa ).
- the outdoor-side low-pressure gas connection pipe 69 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the branch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 ) by brazing.
- the control unit 19 is constituted by being connected to control boards or the like (not illustrated) provided in, for example, the outdoor unit 2 , the indoor units 3 a, 3 b, 3 c, and 3 d, and the relay units 4 a, 4 b, 4 c, and 4 d to communicate therewith. In FIG. 9 , however, the control unit 19 is illustrated at a position separated from the outdoor unit 2 , the indoor units 3 a, 3 b, 3 c , and 3 d, and the relay units 4 a, 4 b, 4 c, and 4 d for the convenience of illustration.
- the control unit 19 controls the components 21 , 22 , 24 , 25 a, 25 b, 26 , 44 , 51 a to 51 d, 55 a to 55 d, 58 a to 58 d, and 59 a to 59 d of the air conditioner 1 (in this case, the outdoor unit 2 , the indoor units 3 a, 3 b, 3 c, and 3 d, and the relay units 4 a, 4 b, 4 c, and 4 d ), that is, controls the entire operation of the air conditioner 1 in accordance with the detection signals of the above-described various sensors 36 , 37 a, 37 b, 38 , 57 a, 57 b, 57 c, and 57 d.
- the operation of the air conditioner 1 when the refrigerant does not leak is described next with reference to FIG. 9 .
- the air conditioner 1 performs cooling only operation, heating only operation, cooling main operation, and heating main operation.
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 provided in the outdoor liquid-refrigerant pipe 34 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d in cooling operation and cooling main operation.
- the operation of the air conditioner 1 which is described below is performed by the control unit 19 that controls the components of the air conditioner 1 .
- cooling only operation for example, when all the indoor units 3 a, 3 b, 3 c, and 3 d perform cooling operation (that is, operation in which all the indoor heat exchangers 52 a, 52 b , 52 c, and 52 d function as the evaporators of the refrigerant and the outdoor heat exchangers 23 a and 23 b function as the radiators of the refrigerant), the switching mechanisms 22 a and 22 b are switched to the outdoor radiation state (the state in which the switching mechanisms 22 a and 22 b are indicated by solid lines in FIG. 9 ), and the compressor 21 , the outdoor fan 24 , and the indoor fans 55 a, 55 b, 55 c, and 55 d are driven.
- the third switching mechanism 22 c is switched to the refrigerant lead-in state (the state in which the switching mechanism 22 c is indicated by solid lines in FIG. 9 ), and the first cooling/heating switching valves 58 a, 58 b , 58 c, and 58 d and the second cooling/heating switching valves 59 a, 59 b, 59 c, and 59 d of the relay units 4 a, 4 b, 4 c, and 4 d are opened.
- the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchangers 23 a and 23 b via the switching mechanisms 22 a and 22 b.
- the refrigerant sent to the outdoor heat exchangers 23 a and 23 b is condensed by being cooled through heat exchange with the outdoor air supplied by the outdoor fan 24 in the outdoor heat exchangers 23 a and 23 b that function as the radiators of the refrigerant.
- the refrigerant flows out from the outdoor unit 2 via the outdoor expansion valves 25 a and 25 b, the refrigerant cooler 45 , the liquid-pressure adjustment expansion valve 26 , and the liquid-side shutoff valve 27 .
- the refrigerant flowing out from the outdoor unit 2 is branched and sent to the relay units 4 a, 4 b, 4 c, and 4 d via the liquid-refrigerant connection pipe 5 (the joint pipe portion and the first branch pipe portions 5 a, 5 b, 5 c, and 5 d ).
- the refrigerant sent to the relay units 4 a , 4 b, 4 c, and 4 d is sent to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the refrigerant sent to the indoor units 3 a, 3 b, 3 c, and 3 d is decompressed by the indoor expansion valves 51 a, 51 b, 51 c, and 51 d and then sent to the indoor heat exchangers 52 a, 52 b, 52 a, and 52 b.
- the refrigerant sent to the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d is evaporated by being heated through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 a, 55 b, 55 c, and 55 d in the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d that function as the evaporators of the refrigerant.
- the refrigerant flows out from the indoor units 3 a, 3 b , 3 c, and 3 d.
- the indoor air cooled by the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d is sent to the air-conditioning target spaces and the air-conditioning target spaces are cooled by using the cooled indoor air.
- the refrigerant flowing out from the indoor units 3 a, 3 b, 3 c, and 3 d is sent to the relay units 4 a, 4 b, 4 c, and 4 d via the branch pipe portions 6 a, 6 b, 6 c, and 6 d of the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the relay units 4 a, 4 b, 4 c, and 4 d flows out from the relay units 4 a, 4 b, 4 c, and 4 d via the first cooling/heating switching valves 58 a, 58 b, 58 c , and 58 d and the second cooling/heating switching valves 59 a, 59 b, 59 c, and 59 d.
- the refrigerant flowing out from the relay units 4 a, 4 b, 4 c, and 4 d is joined and sent to the outdoor unit 2 via the high/low-pressure gas-refrigerant connection pipe 7 (the joint pipe portion and the branch pipe portions 7 a, 7 b, 7 c, and 7 d ) and the low-pressure gas-refrigerant connection pipe 8 (the joint pipe portion and the branch pipe portions 8 a, 8 b, 8 c, and 8 d ).
- the refrigerant sent to the outdoor unit 2 is sucked into the compressor 21 via the gas-side shutoff valves 28 a and 28 b and the third switching mechanism 22 c.
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 , so that the two-phase refrigerant feed can be properly performed.
- the control content relating to the two-phase refrigerant feed is similar to the control content relating to the two-phase refrigerant feed by the air conditioner 1 according to one or more embodiments, and hence the description thereof is omitted.
- the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into the gas-liquid two-phase state.
- the liquid-refrigerant connection pipe 5 is less likely filled with the refrigerant in the liquid state as compared with the case where the refrigerant flowing through the liquid-refrigerant connection pipe 5 is in the liquid state.
- the amount of refrigerant existing in the liquid-refrigerant connection pipe 5 can be decreased by that amount.
- heating only operation for example, when all the indoor units 3 a, 3 b, 3 c, and 3 d perform heating operation (that is, operation in which all the indoor heat exchangers 52 a, 52 b , 52 c, and 52 d function as the radiators of the refrigerant and the outdoor heat exchangers 23 a and 23 b function as the evaporators of the refrigerant), the switching mechanisms 22 a and 22 b are switched to the outdoor evaporation state (the state in which the switching mechanisms 22 a and 22 b are indicated by broken lines in FIG. 9 ), and the compressor 21 , the outdoor fan 24 , and the indoor fans 55 a, 55 b, 55 c, and 55 d are driven.
- heating operation that is, operation in which all the indoor heat exchangers 52 a, 52 b , 52 c, and 52 d function as the radiators of the refrigerant and the outdoor heat exchangers 23 a and 23 b function as the evaporators of the refrigerant
- the third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which the switching mechanism 22 c is indicated by broken lines in FIG. 9 ), and the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d and the second cooling/heating switching valves 59 a, 59 b, 59 c , and 59 d of the relay units 4 a, 4 b, 4 c, and 4 d are closed.
- the high-pressure refrigerant discharged from the compressor 21 flows out from the outdoor unit 2 via the third switching mechanism 22 c and the gas-side shutoff valve 28 a.
- the refrigerant flowing out from the outdoor unit 2 is branched and sent to the relay units 4 a, 4 b, 4 c, and 4 d via the gas-refrigerant connection pipe 6 (the joint pipe portion and the branch pipe portions 7 a, 7 b, 7 c, and 7 d of the high/low-pressure gas-refrigerant connection pipe 7 ).
- the refrigerant sent to the relay units 4 a, 4 b, 4 c, and 4 d flows out from the relay units 4 a, 4 b, 4 c, and 4 d via the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d.
- the refrigerant flowing out from the relay units 4 a, 4 b, 4 c, and 4 d is sent to the indoor units 3 a, 3 b, 3 c, and 3 d via the branch pipe portions 6 a, 6 b, 6 c, and 6 d (the portions of the gas-refrigerant connection pipe 6 connecting the relay units 4 a, 4 b, 4 c, and 4 d to the indoor units 3 a, 3 b, 3 c, and 3 d ).
- the refrigerant sent to the indoor units 3 a, 3 b, 3 c, and 3 d is sent to the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d.
- the high-pressure refrigerant sent to the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d is condensed by being cooled through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 a, 55 b, 55 c, and 55 d in the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d that function as the radiators of the refrigerant.
- the refrigerant is decompressed by the indoor expansion valves 51 a, 51 b, 51 c, and 51 d and then flows out from the indoor units 3 a, 3 b, 3 c, and 3 d.
- the indoor air heated by the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d is sent to the air-conditioning target spaces and the air-conditioning target spaces are heated by using the heated indoor air.
- the refrigerant flowing out from the indoor units 3 a, 3 b, 3 c, and 3 d is sent to the relay units 4 a, 4 b, 4 c, and 4 d via the second branch pipe portions 5 aa , 5 bb , 5 cc , and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting the relay units 4 a, 4 b, 4 c, and 4 d to the indoor units 3 a, 3 b, 3 c, and 3 d ).
- the refrigerant sent to the relay units 4 a, 4 b, 4 c, and 4 d flows out from the relay units 4 a, 4 b, 4 c, and 4 d.
- the refrigerant flowing out from the relay units 4 a, 4 b, 4 c, and 4 d is joined and sent to the outdoor unit 2 via the liquid-refrigerant connection pipe 5 (the joint pipe portion and the first branch pipe portions 5 a, 5 b, 5 c, and 5 d ).
- the refrigerant sent to the outdoor unit 2 is sent to the outdoor expansion valves 25 a and 25 b via the liquid-side shutoff valve 27 and the refrigerant cooler 45 .
- the refrigerant sent to the outdoor expansion valves 25 a and 25 b is decompressed by the outdoor expansion valves 25 a and 25 b and then is sent to the outdoor heat exchangers 23 a and 23 b.
- the refrigerant sent to the outdoor heat exchangers 23 a and 23 b is evaporated by being heated through heat exchange with the outdoor air supplied by the outdoor fan 24 .
- the refrigerant is sucked into the compressor 21 via the switching mechanisms 22 a and 22 b.
- control unit 19 performs control to fix the opening degree of the liquid-pressure adjustment expansion valve 26 in a fully opened state.
- the opening degree of the refrigerant return expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to the refrigerant return pipe 41 .
- cooling main operation for example, when the indoor units 3 b, 3 c, and 3 d perform cooling operation, the indoor unit 3 a performs heating operation (that is, operation in which the indoor heat exchangers 52 b, 52 c, and 52 d function as the evaporators of the refrigerant and the indoor heat exchanger 52 a functions as the radiator of the refrigerant), and the indoor heat exchangers 23 a and 23 b function as the radiators of the refrigerant, the switching mechanisms 22 a and 22 b are switched to the outdoor radiation state (the state in which the switching mechanisms 22 a and 22 b are indicated by solid lines in FIG.
- the third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which the switching mechanism 22 c is indicated by broken lines in FIG.
- the first cooling/heating switching valve 58 a of the relay unit 4 a and the second cooling/heating switching valves 59 b , 59 c, and 59 d of the relay units 4 b, 4 c, and 4 d are opened, and the second cooling/heating switching valve 59 a of the relay unit 4 a as well as the first cooling/heating switching valves 58 b 58 c, and 58 d of the relay units 4 b, 4 c, and 4 d are closed.
- part of the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchangers 23 a and 23 b via the switching mechanisms 22 a and 22 b, and the residual part of the high-pressure refrigerant flows out from the outdoor unit 2 via the third switching mechanism 22 c and the gas-side shutoff valve 28 a.
- the refrigerant sent to the outdoor heat exchangers 23 a and 23 b is condensed by being cooled through heat exchange with the outdoor air supplied by the outdoor fan 24 in the outdoor heat exchangers 23 a and 23 b that function as the radiators of the refrigerant.
- the refrigerant flows out from the outdoor unit 2 via the outdoor expansion valves 25 a and 25 b, the refrigerant cooler 45 , the liquid-pressure adjustment expansion valve 26 , and the liquid-side shutoff valve 27 .
- the refrigerant flowing out from the outdoor unit 2 via the third switching mechanism 22 c and so forth is sent to the relay unit 4 a via the gas-refrigerant connection pipe 6 (the joint pipe portion and the branch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7 ).
- the refrigerant sent to the relay unit 4 a flows out from the relay unit 4 a via the first cooling/heating switching valve 58 a.
- the refrigerant flowing out from the relay unit 4 a is sent to the indoor unit 3 a via the branch pipe portion 6 a (the portion of the gas-refrigerant connection pipe 6 connecting the relay unit 4 a to the indoor unit 3 a ).
- the refrigerant sent to the indoor unit 3 a is sent to the indoor heat exchanger 52 a.
- the high-pressure refrigerant sent to the indoor heat exchanger 52 a is condensed by being cooled through heat exchange with the indoor air supplied from the air-conditioning target space by the indoor fan 55 a in the indoor heat exchanger 52 a that functions as the radiator of the refrigerant.
- the refrigerant is decompressed by the indoor expansion valve 51 a and then flows out from the indoor unit 3 a.
- the indoor air heated by the indoor heat exchanger 52 a is sent to the air-conditioning target space and the air-conditioning target space is heated by using the heated indoor air.
- the refrigerant flowing out from the indoor unit 3 a is sent to the relay unit 4 a via the second branch pipe portion 5 aa (the portion of the liquid-refrigerant connection pipe 5 connecting the relay unit 4 a to the indoor unit 3 a ).
- the refrigerant sent to the relay unit 4 a flows out from the relay unit 4 a.
- the refrigerant flowing out from the relay unit 4 a is sent to the joint pipe portion of the liquid-refrigerant connection pipe 5 via the first branch pipe portion 5 a, and is joined to the refrigerant flowing out from the outdoor unit 2 via the outdoor heat exchangers 23 a and 23 b .
- the refrigerant is branched and sent to the relay units 4 b, 4 c, and 4 d via the first branch pipe portions 5 b, 5 c, and 5 d of the liquid-refrigerant connection pipe 5 .
- the refrigerant sent to the relay units 4 b, 4 c, and 4 d flows out from the relay units 4 b, 4 c, and 4 d.
- the refrigerant flowing out from the relay units 4 b, 4 c, and 4 d is sent to the indoor units 3 b, 3 c, and 3 d via the second branch pipe portions 5 bb , 5 cc , and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting the relay units 4 b, 4 c, and 4 d to the indoor units 3 b, 3 c, and 3 d ).
- the refrigerant sent to the indoor units 3 b, 3 c, and 3 d is decompressed by the indoor expansion valves 51 b, 51 c, and 51 d and then sent to the indoor heat exchangers 52 b , 52 a, and 52 b.
- the refrigerant sent to the indoor heat exchangers 52 b, 52 c, and 52 d is evaporated by being heated through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 b, 55 c, and 55 d in the indoor heat exchangers 52 b, 52 c, and 52 d that function as the evaporators of the refrigerant.
- the refrigerant flows out from the indoor units 3 b, 3 c, and 3 d.
- the indoor air cooled by the indoor heat exchangers 52 b, 52 c, and 52 d is sent to the air-conditioning target spaces and the air-conditioning target spaces are cooled by using the cooled indoor air.
- the refrigerant flowing out from the indoor units 3 b, 3 c, and 3 d is sent to the relay units 4 b, 4 c, and 4 d via the branch pipe portions 6 b, 6 c, and 6 d of the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the relay units 4 b, 4 c, and 4 d flows out from the relay units 4 b , 4 c, and 4 d via the second cooling/heating switching valves 59 b, 59 c, and 59 d.
- the refrigerant flowing out from the relay units 4 b, 4 c, and 4 d is joined and sent to the outdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 (the joint pipe portion and the branch pipe portions 8 b, 8 c, and 8 d ).
- the refrigerant sent to the outdoor unit 2 is sucked into the compressor 21 via the gas-side shutoff valves 28 a and 28 b and the third switching mechanism 22 c.
- the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressure adjustment expansion valve 26 and hence sending the refrigerant from the outdoor unit 2 to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between the refrigerant cooler 45 and the liquid-pressure adjustment expansion valve 26 , so that the two-phase refrigerant feed can be properly performed.
- heating main operation for example, when the indoor units 3 b, 3 c, and 3 d perform heating operation, the indoor unit 3 a performs cooling operation (that is, operation in which the indoor heat exchangers 52 b, 52 c, and 52 d function as the radiators of the refrigerant and the indoor heat exchanger 52 a functions as the evaporator of the refrigerant), and the indoor heat exchangers 23 a and 23 b function as the evaporators of the refrigerant, the switching mechanisms 22 a and 22 b are switched to the outdoor evaporation state (the state in which the switching mechanisms 22 a and 22 b are indicated by solid lines in FIG.
- cooling operation that is, operation in which the indoor heat exchangers 52 b, 52 c, and 52 d function as the radiators of the refrigerant and the indoor heat exchanger 52 a functions as the evaporator of the refrigerant
- the indoor heat exchangers 23 a and 23 b function as the evaporators of the refriger
- the third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which the switching mechanism 22 c is indicated by broken lines in FIG. 9 ), the second cooling/heating switching valves 59 b, 59 c, and 59 d of the relay units 4 b, 4 c, and 4 d are closed, and the second cooling/heating switching valve 59 a of the relay unit 4 a as well as the first cooling/heating switching valves 58 b 58 c, and 58 d of the relay units 4 b, 4 c, and 4 d are opened.
- the high-pressure refrigerant discharged from the compressor 21 flows out from the outdoor unit 2 via the third switching mechanism 22 c and the gas-side shutoff valve 28 a.
- the refrigerant flowing out from the outdoor unit 2 is branched and sent to the relay units 4 b, 4 c, and 4 d via the gas-refrigerant connection pipe 6 (the joint pipe portion and the branch pipe portions 7 b, 7 c, and 7 d of the high/low-pressure gas-refrigerant connection pipe 7 ).
- the refrigerant sent to the relay units 4 b, 4 c, and 4 d flows out from the relay units 4 b, 4 c , and 4 d via the first cooling/heating switching valves 58 b, 58 c, and 58 d.
- the refrigerant flowing out from the relay units 4 b, 4 c, and 4 d is sent to the indoor units 3 b, 3 c, and 3 d via the branch pipe portions 6 b, 6 c, and 6 d (the portions of the gas-refrigerant connection pipe 6 connecting the relay units 4 b, 4 c, and 4 d to the indoor units 3 b , 3 c, and 3 d ).
- the refrigerant sent to the indoor units 3 b, 3 c, and 3 d is sent to the indoor heat exchangers 52 b, 52 c, and 52 d.
- the high-pressure refrigerant sent to the indoor heat exchangers 52 b, 52 c, and 52 d is condensed by being cooled through heat exchange with the indoor air supplied from the air-conditioning target spaces by the indoor fans 55 b, 55 c, and 55 d in the indoor heat exchangers 52 b, 52 c, and 52 d that function as the radiators of the refrigerant.
- the refrigerant is decompressed by the indoor expansion valves 51 b, 51 c, and 51 d and then flows out from the indoor units 3 b, 3 c, and 3 d.
- the indoor air heated by the indoor heat exchangers 52 b, 52 c, and 52 d is sent to the air-conditioning target spaces and the air-conditioning target spaces are heated by using the heated indoor air.
- the refrigerant flowing out from the indoor units 3 b, 3 c, and 3 d is sent to the relay units 4 b, 4 c, and 4 d via the second branch pipe portions 5 bb , 5 cc , and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting the relay units 4 b, 4 c, and 4 d to the indoor units 3 b, 3 c, and 3 d ).
- the refrigerant sent to the relay units 4 b, 4 c, and 4 d flows out from the relay units 4 b, 4 c, and 4 d.
- the refrigerant flowing out from the relay units 4 a, 4 b, 4 c, and 4 d is joined to the joint pipe portion via the first branch pipe portions 5 a, 5 b, 5 c, and 5 d of the liquid-refrigerant connection pipe 5 , part of the refrigerant is branched to the first branch pipe portion 5 a and sent to the relay unit 4 a, and the residual part of the refrigerant is sent to the outdoor unit 2 via the joint pipe portion of the liquid-refrigerant connection pipe 5 .
- the refrigerant sent to the relay unit 4 a flows out from the relay unit 4 a.
- the refrigerant flowing out from the relay unit 4 a is sent to the indoor unit 3 a via the second branch pipe portion 5 aa (the portion of the liquid-refrigerant connection pipe 5 connecting the relay unit 4 a to the indoor unit 3 a ).
- the refrigerant sent to the indoor units 3 a is decompressed by the indoor expansion valve 51 a and then sent to the indoor heat exchanger 52 a.
- the refrigerant sent to the indoor heat exchanger 52 a is evaporated by being heated through heat exchange with the indoor air supplied from the air-conditioning target space by the indoor fan 55 a in the indoor heat exchanger 52 a that functions as the evaporator of the refrigerant.
- the refrigerant flows out from the indoor unit 3 a.
- the indoor air cooled by the indoor heat exchanger 52 a is sent to the air-conditioning target space and the air-conditioning target space is cooled by using the cooled indoor air.
- the refrigerant flowing out from the indoor unit 3 a is sent to the relay unit 4 a via the branch pipe portion 6 a of the gas-refrigerant connection pipe 6 .
- the refrigerant sent to the relay unit 4 a flows out from the relay unit 4 a via the second cooling/heating switching valve 59 a.
- the refrigerant flowing out from the relay unit 4 a is sent to the outdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 (the joint pipe portion and the branch pipe portion 8 a ).
- the refrigerant sent to the outdoor unit 2 via the joint pipe portion of the liquid-refrigerant connection pipe 5 is sent to the outdoor expansion valves 25 a and 25 b via the liquid-side shutoff valve 27 , the liquid-pressure adjustment expansion valve 26 , and the refrigerant cooler 45 .
- the refrigerant sent to the outdoor expansion valves 25 a and 25 b is decompressed by the outdoor expansion valves 25 a and 25 b and then is sent to the outdoor heat exchangers 23 a and 23 b.
- the refrigerant sent to the outdoor heat exchangers 23 a and 23 b is evaporated by being heated through heat exchange with the outdoor air supplied by the outdoor fan 24 .
- the refrigerant is joined to the refrigerant sent to the outdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 and is sucked into the compressor 21 , via the switching mechanisms 22 a and 22 b.
- control unit 19 performs control to fix the opening degree of the liquid-pressure adjustment expansion valve 26 in a fully opened state.
- the opening degree of the refrigerant return expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to the refrigerant return pipe 41 .
- FIG. 11 is a flowchart of an operation when a refrigerant leaks in the air conditioner 1 according to one or more embodiments of the present invention.
- the operation of the air conditioner 1 which is described below is performed by the control unit 19 that controls the components of the air conditioner 1 (the outdoor unit 2 , the indoor units 3 a , 3 b, 3 c, and 3 d, and the relay units 4 a, 4 b, 4 c, and 4 d ) like the operation when the refrigerant does not leak.
- the air conditioner 1 is provided with the refrigerant sensors 57 a, 57 b, 57 c, and 57 d serving as the refrigerant leakage detecting means as described above.
- the refrigerant sensors 57 a, 57 b, 57 c, and 57 d detect leakage of the refrigerant
- the indoor expansion valves 51 a, 51 b, 51 c, and 51 d and the cooling/heating switching valves 58 a, 58 b, 58 c, 58 d, 59 a, 59 b , 59 c, and 59 d are closed in accordance with the information of the refrigerant sensors 57 a, 57 b , 57 c, and 57 d.
- the indoor units 3 a, 3 b, 3 c, and 3 d can be isolated. Accordingly, the refrigerant can be inhibited from flowing from the refrigerant connection pipes 5 and 6 to the indoor units 3 a, 3 b, 3 c, and 3 d.
- the indoor expansion valves 51 a, 51 b, 51 c, and 51 d are used also as liquid-side shutoff valves
- the cooling/heating switching valves 58 a, 58 b, 58 c, 58 d, 59 a, 59 b, 59 c, and 59 d are used also as gas-side shutoff valves, and these valves are closed, thereby providing a refrigerant shutoff function when the refrigerant leaks from the indoor units 3 a, 3 b, 3 c, and 3 d.
- step ST 1 when the refrigerant sensors 57 a, 57 b, 57 c, and 57 d detect leakage of the refrigerant (step ST 1 ), the control unit 19 closes the indoor expansion valves 51 a, 51 b, 51 c , and 51 d and the cooling/heating switching valves 58 a, 58 b, 58 c, 58 d, 59 a, 59 b, 59 c, and 59 d (step ST 4 ).
- an alarm may be given (step ST 2 ).
- the compressor 21 may be stopped (step ST 3 ) to suppress an excessive increase in the pressure of the refrigerant.
- the indoor expansion valves 51 a, 51 b, 51 c, and 51 d and the cooling/heating switching valves 58 a, 58 b, 58 c, 58 d, 59 a, 59 b, 59 c, and 59 d are closed in accordance with the information of the refrigerant sensors 57 a, 57 b, 57 c, and 57 d serving as the refrigerant leakage detecting means when the refrigerant leaks.
- the refrigerant is inhibited from flowing from the refrigerant connection pipes 5 and 6 to the indoor units 3 a, 3 b , 3 c, and 3 d, and increase in concentration of the refrigerant in the air-conditioning target spaces can be suppressed.
- the air conditioner 1 and the indoor units 3 a, 3 b, 3 c, and 3 d used for the air conditioner 1 have the following features.
- the air conditioner 1 and the indoor units 3 a, 3 b, 3 c , and 3 d used for the air conditioner 1 according to one or more embodiments also have leakage of the refrigerant from the brazing portions 82 a, 82 b, 82 c, and 82 d brazing the indoor expansion valves 51 a, 51 b, 51 c, and 51 d and the connection-side indoor liquid-refrigerant pipes 72 a, 72 b , 72 c, and 72 d when the indoor expansion valves 51 a, 51 b, 51 c, and 51 d are used also as the shutoff valves on the liquid sides of the indoor units 3 a, 3 b, 3 c, and 3 d.
- leakage of the refrigerant from the brazing portions 82 a, 82 b, 82 c, and 82 d is reduced by providing coating materials 11 a, 11 b, 11 c, and 11 d at the brazing portions 82 a, 82 b, 82 c, and 82 d.
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a, 3 b, 3 c, and 3 d can be added while the increase in the cost and the sizes of the indoor units 3 a, 3 b, 3 c, and 3 d due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a, 3 b, 3 c, and 3 d is reduced as much as possible.
- the cooling/heating switching valves 58 a, 58 b, 58 c , 58 d, 59 a, 59 b, 59 c, and 59 d of the relay units 4 a, 4 b, 4 c, and 4 d used for individually switching the operating states of the indoor units 3 a, 3 b, 3 c, and 3 d that is, the states in which the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d function as the evaporators of the refrigerant and function as the radiators of the refrigerant
- the gas-side shutoff valves that is, the states in which the indoor heat exchangers 52 a, 52 b, 52 c, and 52 d function as the evaporators of the refrigerant and function as the radiators of the refrigerant
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a, 3 b, 3 c, and 3 d can be added while the increase in the cost and the sizes of the indoor units 3 a, 3 b, 3 c, and 3 d due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a, 3 b, 3 c, and 3 d is reduced as much as possible.
- the addition of the refrigerant shutoff function makes the countermeasure to leakage of the refrigerant sufficient.
- connection-side indoor liquid-refrigerant pipes 72 a, 72 b, 72 c, and 72 d include first connection-side indoor liquid-refrigerant pipes 74 a, 74 b, 74 c, and 74 d connected to the indoor expansion valves 51 a, 51 b, 51 c, and 51 d, and second connection-side indoor liquid-refrigerant pipes 75 a , 75 b, 75 c, and 75 d connected to the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portions 5 aa , 5 bb , 5 cc , and 5 dd ).
- the brazing portions 85 a, 85 b, 85 c, 85 d, 86 a , 86 b, 86 c, and 86 d brazing the filters 73 a, 73 b, 73 c, and 73 d with the first connection-side indoor liquid-refrigerant pipes 74 a, 74 b, 74 c, and 74 d and the second connection-side indoor liquid-refrigerant pipes 75 a, 75 b, 75 c, and 75 d are also provided with coating materials 11 a, 11 b, 11 c , 11 d, 12 a, 12 b, 12 c, and 12 d.
- the first connection-side indoor liquid-refrigerant pipes 74 a , 74 b, 74 c, and 74 d including the brazing portions 82 a, 82 b, 82 c, and 82 d and the brazing portions 85 a, 85 b, 85 c, and 85 d are provided with the coating materials 11 a, 11 b, 11 c, and 11 d .
- the second connection-side indoor liquid-refrigerant pipes 75 a, 75 b, 75 c, and 75 d including the brazing portions 86 a, 86 b, 86 c, and 86 d and the brazing portions 83 aa , 83 bb , 83 cc , and 83 dd are provided with coating materials 12 a, 12 b, 12 c, and 12 d.
- the coating materials 12 a, 12 b, 12 c, and 12 d may be provided to include the brazing portions brazing the second connection-side indoor liquid-refrigerant pipes 75 a , 75 b, 75 c, and 75 d and the liquid-refrigerant connection pipe 5 (in this case, the branch pipe portions 5 aa , 5 bb , 5 cc , and 5 dd ).
- the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units 3 a, 3 b, 3 c, and 3 d can be added while the increase in the cost and the sizes of the indoor units 3 a, 3 b, 3 c, and 3 d due to the provision of the shutoff valves on the liquid sides of the indoor units 3 a, 3 b, 3 c, and 3 d is reduced as much as possible.
- the cooling/heating switching valves 58 a, 58 b, 58 c, 58 d, 59 a, 59 b, 59 c, and 59 d serving as the gas-side shutoff valves are connected to the gas connection pipes 62 a, 62 b, 62 c, and 62 d connected to the gas-refrigerant connection pipe 6 (the indoor-side high-pressure gas connection pipes 66 a, 66 b, 66 c, and 66 d , the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d, the indoor-side low-pressure gas connection pipes 68 a, 68 b, 68 c, and 68 d, and the outdoor-side low-pressure gas connection pipes 69 a, 69 b, 69 c, and 69 d ) by brazing.
- brazing portions 92 a, 92 b, 92 c, and 92 d brazing the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d and the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d may corrode and the refrigerant may leak from the corroding portions.
- the brazing portions 92 a, 92 b, 92 c, and 92 d brazing the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d and the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d are also provided with coating materials 13 a, 13 b, 13 c, and 13 d.
- the coating materials 13 a, 13 b, 13 c, 13 d, 14 a, 14 b, 14 c , and 14 d may be also provided at only the brazing portions 92 a, 92 b, 92 c, 92 d, 94 a, 94 b, 94 c , and 94 d, or may be also provided at a portion other than the brazing portions 92 a, 92 b, 92 c , 92 d, 94 a, 94 b, 94 c, and 94 d.
- the coating materials 13 a , 13 b, 13 c, and 13 d may be provided in a range from the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d to the pipe joint portions 96 a, 96 b, 96 c, and 96 d of the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d (that is, so as to include the brazing portions 92 a, 92 b, 92 c, and 92 d and the brazing portions 96 aa , 96 bb , 96 cc , and 96 dd ).
- the coating materials 13 a, 13 b, 13 c, and 13 d may be provided in a range from the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d to the brazing portions brazing the outdoor-side gas connection pipes 67 a, 67 b, 67 c, and 67 d and the gas-refrigerant connection pipe 6 (in this case, the first branch pipe portions 7 a, 7 b, 7 c, and 7 d of the high/low-pressure gas-refrigerant connection pipe 7 ).
- the coating materials 14 a, 14 b, 14 c, and 14 d may be provided in a range from the second cooling/heating switching valves 59 a, 59 b, 59 c, and 59 d to the pipe joint portions 97 a, 97 b, 97 c, and 97 d of the outdoor-side low-pressure gas connection pipes 69 a, 69 b, 69 c, and 69 d (that is, so as to include the brazing portions 94 a, 94 b , 94 c, and 94 d and the brazing portions 97 aa , 97 bb , 97 cc , and 97 dd ).
- the coating materials 14 a, 14 b, 14 c , and 14 d may be provided in a range from the second cooling/heating switching valves 59 a, 59 b , 59 c, and 59 d to the brazing portions brazing the outdoor-side low-pressure gas connection pipes 69 a, 69 b, 69 c, and 69 d and the gas-refrigerant connection pipe 6 (in this case, the branch pipe portions 8 a, 8 b, 8 c, and 8 d of the low-pressure gas-refrigerant connection pipe 8 ).
- leakage of the refrigerant from the brazing portions 92 a, 92 b, 92 c, and 92 d brazing the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d and the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d is reduced, leakage of the refrigerant from the brazing portions 94 a, 94 b, 94 c, and 94 d brazing the second cooling/heating switching valves 59 a, 59 b, 59 c, and 59 d and the outdoor-side low-pressure gas connection pipes 69 a, 69 b , 69 c, and 69 d is reduced, and hence the relay units 4 a, 4 b, 4 c, and 4 d can be arranged in the air-conditioning target spaces together with the indoor units 3 a, 3 b, 3 c, and 3 d.
- the brazing portions 92 a, 92 b, 92 c, and 92 d brazing the first cooling/heating switching valves 58 a, 58 b, 58 c, and 58 d and the outdoor-side high-pressure gas connection pipes 67 a, 67 b, 67 c, and 67 d as well as the brazing portions 94 a, 94 b , 94 c, and 94 d brazing the second cooling/heating switching valves 59 a, 59 b, 59 c, and 59 d and the outdoor-side low-pressure gas connection pipes 69 a, 69 b, 69 c, and 69 d may be provided with the coating materials 13 a, 13 b, 13 c, 13 d, 14 a, 14 b, 14 c
- the degree of freedom is ensured for arrangement of the relay units 4 a , 4 b, 4 c, and 4 d.
- step ST 1 when the refrigerant sensors 57 a, 57 b, 57 c, and 57 d detect leakage of the refrigerant (step ST 1 ), the control unit 19 closes only the indoor expansion valve and the cooling/heating switching valve corresponding to the indoor unit in which the refrigerant leaks among the plurality of indoor units 3 a, 3 b, 3 c, and 3 d (step ST 5 ). Then, by continuing the circulation of the refrigerant in the refrigerant circuit 10 without stopping the compressor 21 , the cooling operation or heating operation of the indoor unit in which the refrigerant does not leak is continued (step ST 6 ).
- the relay units 4 a, 4 b, 4 c, and 4 d respectively corresponding to the indoor units 3 a, 3 b, 3 c, and 3 d are provided; however, it is not limited thereto.
- a relay unit may be collectively constituted of all the relay units 4 a, 4 b , 4 c, and 4 d, or some of the relay units 4 a, 4 b, 4 c, and 4 d.
- the present invention can be widely applied to an air conditioner configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, and an indoor unit used for the air conditioner.
- refrigerant sensor refrigerant leakage detecting means
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- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
An air conditioner includes: an outdoor unit; a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe; an indoor unit; a gas-side shutoff valve; a refrigerant sensor; and a controller. The indoor unit is connected to the outdoor unit via the liquid-refrigerant and gas-refrigerant connection pipes, is arranged in an air-conditioning target space, and includes: an indoor heat exchanger that performs heat exchange between a refrigerant circulated between the indoor unit and the outdoor unit via the liquid-refrigerant and gas-refrigerant connection pipes and air sent to the air-conditioning target space; an indoor expansion valve that decompresses the refrigerant; a heat-exchange-side indoor liquid-refrigerant pipe that connects a liquid side of the indoor heat exchanger to the indoor expansion valve; and a connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe.
Description
- The present invention relates to air conditioners and indoor units, and more particularly relates to an air conditioner configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, and an indoor unit used for the air conditioner.
- An existing air conditioner is configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe. An example of such an air conditioner, as disclosed in PTL 1 (International Publication No. 2015/029160), performs two-phase refrigerant feed of decompressing a refrigerant to be brought into a gas-liquid two-phase state in an outdoor unit and then sending the refrigerant to an indoor unit via a liquid-refrigerant connection pipe. The air conditioner that performs the two-phase refrigerant feed can decrease the amount of refrigerant held by the entire air conditioner by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe turns into the gas-liquid two-phase state. The decrease in the amount of refrigerant can decrease the influence on environment in a case where the refrigerant leaks outside the air conditioner.
- Although the amount of refrigerant held by the entire air conditioner is decreased to a certain degree by the two-phase refrigerant feed as disclosed in PTL 1, the decrease in the amount of refrigerant is not occasionally sufficient for the countermeasure to leakage of the refrigerant. This is because, when the refrigerant leaks from the indoor unit, the concentration of the refrigerant increases in the air-conditioning target space where the indoor unit involving leakage of the refrigerant is arranged, and the concentration may exceed its permissible value.
- To address this, a shutoff valve may be added to each of both the liquid side and gas side of the indoor unit so as to isolate the indoor unit involving leakage of the refrigerant and to reduce leakage of the refrigerant into the air-conditioning target space.
- Adding the shutoff valves to both the liquid side and gas side of the indoor unit, however, increases the cost, and further increases the size of the indoor unit if both the shutoff valves on the liquid side and gas side are arranged in the indoor unit.
- According to one or more embodiments of the present invention, in an air conditioner configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe as well as an indoor unit used for the air conditioner, increases in the cost and the size of the indoor unit are minimized and a refrigerant shutoff function when a refrigerant leaks from the indoor unit can be added.
- International Publication No. 2015/029160
- An air conditioner according to one or more embodiments is an air conditioner including an outdoor unit, a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, an indoor unit, a gas-side shutoff valve, refrigerant leakage detecting means, and a control unit. The indoor unit is connected to the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, is arranged in an air-conditioning target space, and includes an indoor heat exchanger, an indoor expansion valve, a heat-exchange-side indoor liquid-refrigerant pipe, and a connection-side indoor liquid-refrigerant pipe. The indoor heat exchanger performs heat exchange between a refrigerant, which is circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and an air, which is sent to the air-conditioning target space. The indoor expansion valve decompresses the refrigerant. The heat-exchange-side indoor liquid-refrigerant pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve. The connection-side indoor liquid-refrigerant pipe connects the indoor expansion valve to the liquid-refrigerant connection pipe. The gas-side shutoff valve is connected to a gas side of the indoor heat exchanger. The refrigerant leakage detecting means detects leakage of the refrigerant. The refrigerant leakage detecting means may be a refrigerant sensor that directly detects the leaked refrigerant, or may be one that estimates the presence or amount of leaked refrigerant on the basis of the relationship between the temperature of the refrigerant in the indoor heat exchanger and the atmospheric temperature of the indoor heat exchanger. The indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing. A brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is provided with a coating material. The control unit causes the indoor expansion valve and the gas-side shutoff valve to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- To add the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit, providing shutoff valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit. To minimize the increase in the cost and the size of the indoor unit, it is desirable to use the indoor expansion valve also as the shutoff valve on the liquid side for the situation in which the refrigerant leaks from the indoor unit.
- In the indoor unit arranged in the air-conditioning target space, however, the connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe is connected to the indoor expansion valve by brazing. The brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion. When the refrigerant leaks from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe, the refrigerant is continuously supplied from the liquid-refrigerant connection pipe to the brazing portion although the indoor expansion valve is closed to function as the shutoff valve on the liquid side of the indoor unit. The refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is difficult to use the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit unless such leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced.
- In this case, by providing the coating material at the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe as described above, leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced, and the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit. As long as the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- Accordingly, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- In an air conditioner according to one or more embodiments, the connection-side indoor liquid-refrigerant pipe includes a first connection-side indoor liquid-refrigerant pipe connected to the indoor expansion valve, a second connection-side indoor liquid-refrigerant pipe connected to the liquid-refrigerant connection pipe, and a filter that is connected between the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe. The filter is connected to the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe by brazing. Brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe each are provided with a coating material.
- In the indoor unit arranged in the air-conditioning target space, a filter may be provided to reduce inflow of foreign substances and so forth into the connection-side indoor liquid-refrigerant pipe and the indoor expansion valve. The filter is also connected to the connection-side indoor liquid-refrigerant pipe (the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe) by brazing. Due to this, the brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portions. This makes difficult to use the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit, like the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe (the first connection-side indoor liquid-refrigerant pipe).
- In this case, by providing the coating materials at the brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe as described above, leakage of the refrigerant from the brazing portions brazing the filter with the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe is reduced, and the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit.
- Even in the case where the filter is provided in the connection-side indoor liquid-refrigerant pipe, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- In an air conditioner according to one or more embodiments, the outdoor unit includes an outdoor heat exchanger and a liquid-pressure adjustment expansion valve. When the refrigerant is sent from the outdoor heat exchanger to the indoor unit via the liquid-refrigerant connection pipe, the control unit controls the liquid-pressure adjustment expansion valve to decompress the refrigerant flowing through the liquid-refrigerant connection pipe to be brought into a gas-liquid two-phase state, and controls the indoor expansion valve to decompress the refrigerant decompressed by the liquid-pressure adjustment expansion valve.
- Since the outdoor unit includes the liquid-pressure adjustment expansion valve as described above, the two-phase refrigerant feed of decompressing the refrigerant to be brought into the gas-liquid two-phase state in the outdoor unit and then sending the refrigerant to the indoor unit via the liquid-refrigerant connection pipe can be performed. Thus, the amount of refrigerant held by the entire air conditioner can be decreased by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe turns into the gas-liquid two-phase state through the two-phase refrigerant feed. However, although the amount of refrigerant held by the entire air conditioner can be decreased by a certain degree through the two-phase refrigerant feed, when the refrigerant leaks from the indoor unit, the concentration of the refrigerant increases in the air-conditioning target space where the indoor unit involving leakage of the refrigerant is arranged, and the concentration may exceed its permissible value. In such a case, the two-phase refrigerant feed is not occasionally sufficient for the countermeasure to leakage of the refrigerant.
- In this case, by providing the coating material at the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe as described above, leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced, and the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit.
- Accordingly, even in the case where the two-phase refrigerant feed is not sufficient for the countermeasure to leakage of the refrigerant, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible. The addition of the refrigerant shutoff function makes the countermeasure to leakage of the refrigerant sufficient.
- In an air conditioner according to one or more embodiments, the indoor unit includes a plurality of the indoor units, and the gas-side shutoff valve is provided to correspond to each of the indoor units.
- In this case, the plurality of indoor units and the plurality of gas-side shutoff valves are provided as described above. Even with this configuration, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor units can be added while the increase in the cost and the sizes of the indoor units due to the provision of the shutoff valves on the liquid sides of the indoor units is reduced as much as possible.
- In an air conditioner according to one or more embodiments, the control unit causes only the indoor expansion valve and the gas-side shutoff valve corresponding to the indoor unit in which the refrigerant leaks among the plurality of indoor units to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- In this case, when the refrigerant leaks from the indoor unit, only the indoor unit in which the refrigerant leaks can be isolated as described above.
- Accordingly, the indoor unit in which the refrigerant does not leak can continue the operation.
- In an air conditioner according to one or more embodiments, the gas-refrigerant connection pipe is provided with an external shutoff valve unit including the gas-side shutoff valve.
- In this case, since the gas-side shutoff valve is arranged outside the indoor unit as described above, the increase in the size of the indoor unit can be suppressed.
- In an air conditioner according to one or more embodiments, the gas-side shutoff valve is connected, by brazing, to an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit, and an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit. A brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is also provided with a coating material.
- In the external shutoff valve unit, the gas-side shutoff valve is connected to the gas connection pipe connected to the gas-refrigerant connection pipe (the indoor-side gas connection pipe and the outdoor-side gas connection pipe) by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe may corrode and the refrigerant may leak from the corroding portion. In contrast, when the external shutoff valve unit is arranged in the air-conditioning target space together with the indoor unit, if the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed, and the refrigerant may continuously leak from the external shutoff valve unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe.
- In this case, since the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the outdoor-side gas connection pipe is reduced, and the external shutoff valve unit can be arranged in the air-conditioning target space together with the indoor unit.
- Accordingly, the degree of freedom is ensured for arrangement of the external shutoff valve unit.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- In an air conditioner according to one or more embodiments, the gas-refrigerant connection pipe is provided with a relay unit including a cooling/heating switching valve that individually switches corresponding one of the plurality of indoor heat exchangers to function as an evaporator or a radiator of the refrigerant. The control unit causes the indoor expansion valve and the cooling/heating switching valve serving as the gas-side shutoff valve to be closed in accordance with information of the refrigerant leakage detecting means when the refrigerant leaks.
- In this case, as described above, the cooling/heating switching valve of the relay unit used for individually switching the operating state of corresponding one of the indoor units (that is, the state in which the indoor heat exchanger functions as the evaporator of the refrigerant and the state in which the indoor heat exchanger functions as the radiator of the refrigerant) is used also as the gas-side shutoff valve. As long as the cooling/heating switching valve can be used also as the shutoff valve on the gas side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- Accordingly, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the gas side of the indoor unit is reduced as much as possible.
- In an air conditioner according to one or more embodiments, the cooling/heating switching valve is connected, by brazing, to an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit, and an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit. A brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is also provided with a coating material.
- In the relay unit, the cooling/heating switching valve is connected to the gas connection pipe connected to the gas-refrigerant connection pipe (the indoor-side gas connection pipe and the outdoor-side gas connection pipe) by brazing. Due to this, when the relay unit is arranged in the air-conditioning target space together with the indoor unit, the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe may corrode and the refrigerant may leak from the corroding portion. In this case, when the relay unit is arranged in the air-conditioning target space together with the indoor unit, if the refrigerant leaks from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the cooling/heating switching valve is closed, and the refrigerant may continuously leak from the relay unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe.
- In this case, since the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the cooling/heating switching valve and the outdoor-side gas connection pipe is reduced, and the relay unit can be arranged in the air-conditioning target space together with the indoor unit.
- Accordingly, the degree of freedom is ensured for arrangement of the relay unit.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- In an air conditioner according to one or more embodiments, the gas-side shutoff valve is provided in the indoor unit. The indoor unit includes a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve, and a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe. The gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing. A brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is also provided with a coating material.
- To add the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit, the indoor expansion valve of the indoor unit may be used also as the liquid-side shutoff valve, and the gas-side shutoff valve may be provided at the indoor unit. In this case, the connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe is connected to the gas-side shutoff valve by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion. When the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed. The refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
- In this case, since the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is reduced.
- Accordingly, the shutoff valve provided in the indoor unit is provided on only the gas side, and the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- An indoor unit according to one or more embodiments is an indoor unit connected to an outdoor unit via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, arranged in an air-conditioning target space, and including an indoor heat exchanger, an indoor expansion valve, a heat-exchange-side indoor liquid-refrigerant pipe, and a connection-side indoor liquid-refrigerant pipe. The indoor heat exchanger performs heat exchange between a refrigerant, which is circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and an air, which is sent to the air-conditioning target space. The indoor expansion valve decompresses the refrigerant. The heat-exchange-side indoor liquid-refrigerant pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve. The connection-side indoor liquid-refrigerant pipe connects the indoor expansion valve to the liquid-refrigerant connection pipe. The indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing. A brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is provided with a coating material.
- To add the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit, providing shutoff valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit. To minimize the increase in the cost and the size of the indoor unit, it is desirable to use the indoor expansion valve also as a shutoff valve on the liquid side for the situation in which the refrigerant leaks from the indoor unit.
- In the indoor unit arranged in the air-conditioning target space, however, the connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe is connected to the indoor expansion valve by brazing. The brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion. When the refrigerant leaks from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe, the refrigerant is continuously supplied from the liquid-refrigerant connection pipe to the brazing portion although the indoor expansion valve is closed to function as the shutoff valve on the liquid side of the indoor unit. The refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is difficult to use the indoor expansion valve also as the shutoff valve on the liquid side of the indoor unit unless such leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced.
- In this case, by providing the coating material at the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe as described above, leakage of the refrigerant from the brazing portion brazing the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe is reduced, and the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit. As long as the indoor expansion valve can be used also as the shutoff valve on the liquid side of the indoor unit, the increase in the cost and the size of the indoor unit can be suppressed by that amount.
- Accordingly, the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added while the increase in the cost and the size of the indoor unit due to the provision of the shutoff valve on the liquid side of the indoor unit is reduced as much as possible.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
- An indoor unit according to one or more embodiments further includes a gas-side shutoff valve that is connected to a gas side of the indoor heat exchanger; a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve; and a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe. The gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing. A brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is also provided with a coating material.
- To add the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit, the indoor expansion valve of the indoor unit may be used also as the liquid-side shutoff valve, and the gas-side shutoff valve may be provided at the indoor unit. In this case, the connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe is connected to the gas-side shutoff valve by brazing. Due to this, the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe may corrode and the refrigerant may leak from the corroding portion. When the refrigerant leaks from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe, the refrigerant is continuously supplied from the gas-refrigerant connection pipe to the brazing portion although the gas-side shutoff valve is closed. The refrigerant may continuously leak from the indoor unit to the air-conditioning target space. Thus, it is required to reduce leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
- In this case, since the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is provided with the coating material as described above, leakage of the refrigerant from the brazing portion brazing the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe is reduced.
- Accordingly, the shutoff valve provided in the indoor unit is provided on only the gas side, and the refrigerant shutoff function for the situation in which the refrigerant leaks from the indoor unit can be added.
- For the coating material, any material can be employed as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed.
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FIG. 1 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention. -
FIG. 2 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting the air conditioner according to one or more embodiments of the present invention. -
FIG. 3 is a flowchart of an operation when a refrigerant leaks in the air conditioner according to one or more embodiments of the present invention. -
FIG. 4 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting an air conditioner according to one or more embodiments of the present invention. -
FIG. 5 illustrates a refrigerant system in the periphery of an indoor unit and an external shutoff valve unit constituting an air conditioner according to one or more embodiments of the present invention. -
FIG. 6 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention. -
FIG. 7 illustrates a refrigerant system in the periphery of an indoor unit constituting the air conditioner according to one or more embodiments of the present invention. -
FIG. 8 is a flowchart of an operation when a refrigerant leaks in an air conditioner according to one or more embodiments of the present invention. -
FIG. 9 is a schematic configuration diagram of an air conditioner according to one or more embodiments of the present invention. -
FIG. 10 illustrates a refrigerant system in the periphery of an indoor unit and a relay unit constituting the air conditioner according to one or more embodiments of the present invention. -
FIG. 11 is a flowchart of an operation when a refrigerant leaks in the air conditioner according to one or more embodiments of the present invention. -
FIG. 12 illustrates a refrigerant system in the periphery of an indoor unit and a relay unit constituting an air conditioner according to one or more embodiments of the present invention. -
FIG. 13 illustrates a refrigerant system in the periphery of an indoor unit and a relay unit constituting an air conditioner according to one or more embodiments of the present invention. -
FIG. 14 is a flowchart of an operation when a refrigerant leaks in an air conditioner according to one or more embodiments of the present invention. - An air conditioner and an indoor unit used for the air conditioner according to one or more embodiments of the present invention are described below with reference to the drawings. It is to be noted that specific configurations of an air conditioner and an indoor unit used for the air conditioner according to one or more embodiments of the present invention are not limited to those of the following embodiments and their modifications, and may be modified within the scope of the gist of the disclosure.
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FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to one or more embodiments of the present invention.FIG. 2 illustrates a refrigerant system in the periphery ofindoor units shutoff valve units - The air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air-conditioning target space in a building or the like through a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an
outdoor unit 2; a plurality of (in this case, two)indoor units refrigerant connection pipe 5 and a gas-refrigerant connection pipe 6 that connect theoutdoor unit 2 to theindoor units shutoff valve units refrigerant connection pipe 5; and acontrol unit 19 that controls components of theoutdoor unit 2, theindoor units shutoff valve units compression refrigerant circuit 10 of the air conditioner 1 is constituted by connecting theoutdoor unit 2, the plurality ofindoor units shutoff valve units refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6. Therefrigerant circuit 10 is filled with a refrigerant such as R32. - The liquid-
refrigerant connection pipe 5 mainly includes a joint pipe portion extending from theoutdoor unit 2, andbranch pipe portions indoor units refrigerant connection pipe 6 mainly includes a joint pipe portion extending from theoutdoor unit 2, firstbranch pipe portions indoor units branch pipe portions 6 aa and 6 bb that connect the externalshutoff valve units indoor units - The
indoor units indoor units indoor units indoor units indoor units outdoor unit 2 via the liquid-refrigerant connection pipe 5, the gas-refrigerant connection pipe 6, and the externalshutoff valve units refrigerant circuit 10 as described above. - Configurations of the
indoor units indoor unit 3 a and theindoor unit 3 b have configurations similar to each other. Hence only the configuration of theindoor unit 3 a is described. For the configuration of theindoor unit 3 b, the description of the components of theindoor unit 3 b is omitted while an index “b” is applied to each component instead of the index “a” indicating each component of theindoor unit 3 a. - The
indoor unit 3 a mainly includes anindoor expansion valve 51 a and anindoor heat exchanger 52 a. In addition, theindoor unit 3 a includes an indoor liquid-refrigerant pipe 53 a that connects the liquid side of theindoor heat exchanger 52 a to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a), and an indoor gas-refrigerant pipe 54 a that connects the gas side of theindoor heat exchanger 52 a to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa). - The
indoor expansion valve 51 a is an electric expansion valve that decompresses the refrigerant. Theindoor expansion valve 51 a is provided in the indoor liquid-refrigerant pipe 53 a. - The
indoor heat exchanger 52 a is a heat exchanger that performs heat exchange between the refrigerant, which is circulated between theindoor unit 3 a and theoutdoor unit 2 via the liquid-refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6, and the indoor air, which is sent to the air-conditioning target space. Theindoor unit 3 a includes anindoor fan 55 a that sucks the indoor air into theindoor unit 3 a, that causes the indoor air to exchange heat with the refrigerant in theindoor heat exchanger 52 a, and then that sends the indoor air into the air-conditioning target space. That is, theindoor unit 3 a includes theindoor fan 55 a as a fan that sends the indoor air, which serves as a cooling source or a heating source of the refrigerant flowing through theindoor heat exchanger 52 a, to theindoor heat exchanger 52 a. Theindoor fan 55 a is driven by anindoor fan motor 56 a. - The indoor liquid-
refrigerant pipe 53 a mainly includes a heat-exchange-side indoor liquid-refrigerant pipe 71 a that connects the liquid side of theindoor heat exchanger 52 a to theindoor expansion valve 51 a, and a connection-side indoor liquid-refrigerant pipe 72 a that connects theindoor expansion valve 51 a to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a). The liquid side of theindoor heat exchanger 52 a is connected to the heat-exchange-side indoor liquid-refrigerant pipe 71 a by brazing. The heat-exchange-side indoor liquid-refrigerant pipe 71 a is connected to theindoor expansion valve 51 a by brazing (the brazing portion is referred to as brazingportion 81 a). Theindoor expansion valve 51 a is connected to the connection-side indoor liquid-refrigerant pipe 72 a by brazing (the brazing portion is referred to as brazingportion 82 a). The connection-side indoor liquid-refrigerant pipe 72 a is connected to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 83 a). The pipejoint portion 83 a is connected to the connection-side indoor liquid-refrigerant pipe 72 a by brazing (the brazing portion is referred to as brazing portion 83 aa). Although not illustrated here, the connection-side indoor liquid-refrigerant pipe 72 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a) by brazing without the mechanical pipe joint such as the pipejoint portion 83 a. - The brazing
portion 82 a brazing theindoor expansion valve 51 a and the connection-side indoor liquid-refrigerant pipe 72 a is provided with acoating material 11 a. For thecoating material 11 a, any material can be employed as long as the material can suppress corrosion of thebrazing portion 82 a. For example, a coating material made of resin can be employed. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be employed. Thecoating material 11 a may be provided at thebrazing portion 82 a, or may be also provided at a portion other than the brazingportion 82 a. For example, as illustrated inFIG. 2 , thecoating material 11 a may be provided in a range from theindoor expansion valve 51 a to the pipejoint portion 83 a of the connection-side indoor liquid-refrigerant pipe 72 a (that is, so as to include thebrazing portion 82 a and the brazing portion 83 aa). When the connection-side indoor liquid-refrigerant pipe 72 a is directly connected to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a) by brazing, thecoating material 11 a may be provided in a range from theindoor expansion valve 51 a to the brazing portion brazing the connection-side indoor liquid-refrigerant pipe 72 a and the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a). - The gas side of the
indoor heat exchanger 52 a is connected to the indoor gas-refrigerant pipe 54 a by brazing. The indoor gas-refrigerant pipe 54 a is connected to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 84 a). The pipejoint portion 84 a is connected to the indoor gas-refrigerant pipe 54 a by brazing (the brazing portion is referred to as brazing portion 84 aa). Although not illustrated here, the indoor gas-refrigerant pipe 54 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa) by brazing. - The
indoor unit 3 a is provided with arefrigerant sensor 57 a serving as refrigerant leakage detecting means for detecting leakage of the refrigerant. Therefrigerant sensor 57 a is provided in theindoor unit 3 a in this case; however, it is not limited thereto. Therefrigerant sensor 57 a may be provided, for example, at a remote controller for operating theindoor unit 3 a, or in the air-conditioning target space where theindoor unit 3 a is arranged. The refrigerant leakage detecting means may be therefrigerant sensor 57 a that directly detects the leaked refrigerant as described above, or alternatively, although it is not employed in this case, the refrigerant leakage detecting means may be one that estimates the presence or amount of leaked refrigerant on the basis of the relationship between the temperature of the refrigerant in theindoor heat exchanger 52 a and the atmospheric temperature of theindoor heat exchanger 52 a. - The
outdoor unit 2 is arranged outside the air-conditioning target space or outside the building or the like. Theoutdoor unit 2 is connected to theindoor units refrigerant connection pipe 5, the gas-refrigerant connection pipe 6, and the externalshutoff valve units refrigerant circuit 10 as described above. - A configuration of the
outdoor unit 2 is described next. - The
outdoor unit 2 mainly includes acompressor 21 and anoutdoor heat exchanger 23. In addition, theoutdoor unit 2 includes aswitching mechanism 22 that switches the operating state between a radiation operating state in which theoutdoor heat exchanger 23 functions as a radiator of the refrigerant, and an evaporation operating state in which theoutdoor heat exchanger 23 functions as an evaporator of the refrigerant. Theswitching mechanism 22 is connected to the suction side of thecompressor 21 via asuction refrigerant pipe 31. The discharge side of thecompressor 21 is connected to theswitching mechanism 22 via adischarge refrigerant pipe 32. Theswitching mechanism 22 is connected to the gas side of theoutdoor heat exchanger 23 via a first outdoor gas-refrigerant pipe 33. The liquid side of theoutdoor heat exchanger 23 is connected to the liquid-refrigerant connection pipe 5 via an outdoor liquid-refrigerant pipe 34. The connection portion of the outdoor liquid-refrigerant pipe 34 with respect to the liquid-refrigerant connection pipe 5 is provided with a liquid-side shutoff valve 27. Theswitching mechanism 22 is connected to the gas-refrigerant connection pipe 6 via a second outdoor gas-refrigerant pipe 35. The connection portion of the second outdoor gas-refrigerant pipe 35 with respect to the gas-refrigerant connection pipe 6 is provided with a gas-side shutoff valve 28. The liquid-side shutoff valve 27 and the gas-side shutoff valve 28 are valves that are manually opened and closed. - The
compressor 21 is a device for compressing the refrigerant. For example, a closed-structure compressor in which a compression element (not illustrated) of positive-displacement type, such as rotary type or scroll type, is rotationally driven by acompressor motor 21 a is used. - The
switching mechanism 22 is a device that can switch the flow of the refrigerant in therefrigerant circuit 10 such that, when theoutdoor heat exchanger 23 functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), theswitching mechanism 22 connects the discharge side of thecompressor 21 to the gas side of the outdoor heat exchanger 23 (see solid lines of theswitching mechanism 22 inFIG. 1 ); and, when theoutdoor heat exchanger 23 functions as the evaporator of the refrigerant (hereinafter, the situation is referred to as “outdoor evaporation state”), theswitching mechanism 22 connects the suction side of thecompressor 21 to the gas side of the outdoor heat exchanger 23 (see broken lines of theswitching mechanism 22 inFIG. 1 ). Theswitching mechanism 22 is, for example, a four-way switching valve. - The
outdoor heat exchanger 23 is a heat exchanger that performs heat exchange between the outdoor air and the refrigerant, which is circulated between theoutdoor unit 2 and theindoor units refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6. Theoutdoor unit 2 includes anoutdoor fan 24 that sucks the outdoor air into theoutdoor unit 2 that causes the outdoor air to exchange heat with the refrigerant in theoutdoor heat exchanger 23, and then that discharges the outdoor air to the outside. That is, theoutdoor unit 2 includes theoutdoor fan 24 as a fan that sends the outdoor air, which serves as a cooling source or a heating source of the refrigerant flowing through theoutdoor heat exchanger 23, to theoutdoor heat exchanger 23. Theoutdoor fan 24 is driven by an outdoor fan motor 24 a. - Focusing only on the
compressor 21, theoutdoor heat exchanger 23, the liquid-refrigerant connection pipe 5, theindoor expansion valves indoor heat exchangers refrigerant connection pipe 6, the air conditioner 1 performs an operation (cooling operation) of circulating the refrigerant in the order of thecompressor 21, theoutdoor heat exchanger 23, the liquid-refrigerant connection pipe 5, theindoor expansion valves indoor heat exchangers refrigerant connection pipe 6, and thecompressor 21. Focusing only on thecompressor 21, theoutdoor heat exchanger 23, the liquid-refrigerant connection pipe 5, theindoor expansion valves indoor heat exchangers refrigerant connection pipe 6, the air conditioner 1 performs an operation (heating operation) of circulating the refrigerant in the order of thecompressor 21, the gas-refrigerant connection pipe 6, theindoor heat exchangers indoor expansion valves refrigerant connection pipe 5, theoutdoor heat exchanger 23, and thecompressor 21. Theswitching mechanism 22 is switched to the outdoor radiation state in cooling operation, and theswitching mechanism 22 is switched to the outdoor evaporation state in heating operation. - In addition, an
outdoor expansion valve 25 and a liquid-pressureadjustment expansion valve 26 are provided in the outdoor liquid-refrigerant pipe 34. Theoutdoor expansion valve 25 is an electric expansion valve that decompresses the refrigerant in heating operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid side of theoutdoor heat exchanger 23. The liquid-pressureadjustment expansion valve 26 is an electric expansion valve that decompresses the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into a gas-liquid two-phase state in cooling operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid-refrigerant connection pipe 5. That is, the liquid-pressureadjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than theoutdoor expansion valve 25. - The air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-
refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units - Furthermore, a
refrigerant return pipe 41 is connected to the outdoor liquid-refrigerant pipe 34, and arefrigerant cooler 45 is provided. Therefrigerant return pipe 41 is a refrigerant pipe that branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 and sends the refrigerant to thecompressor 21. Therefrigerant cooler 45 is a heat exchanger that cools the refrigerant flowing through a portion of the outdoor liquid-refrigerant pipe 34 nearer to theoutdoor heat exchanger 23 than the liquid-pressureadjustment expansion valve 26. Theoutdoor expansion valve 25 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to theoutdoor heat exchanger 23 than therefrigerant cooler 45. The liquid-pressureadjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than the portion to which therefrigerant cooler 45 is connected (in this case, between therefrigerant cooler 45 and the liquid-side shutoff valve 27). - The
refrigerant return pipe 41 is a refrigerant pipe that sends the refrigerant branched from the outdoor liquid-refrigerant pipe 34 to the suction side of thecompressor 21. Therefrigerant return pipe 41 mainly includes a refrigerantreturn inlet pipe 42 and a refrigerantreturn outlet pipe 43. The refrigerantreturn inlet pipe 42 is a refrigerant pipe that branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 from a portion between the liquid side of theoutdoor heat exchanger 23 and the liquid-pressure adjustment expansion valve 26 (in this case, a portion between theoutdoor expansion valve 25 and the refrigerant cooler 45) and sends the refrigerant to the inlet of therefrigerant cooler 45 on the side of therefrigerant return pipe 41. The refrigerantreturn inlet pipe 42 is provided with a refrigerantreturn expansion valve 44 that adjusts the flow rate of the refrigerant flowing through therefrigerant cooler 45 while decompressing the refrigerant flowing through therefrigerant return pipe 41. The refrigerantreturn expansion valve 44 is an electric expansion valve. The refrigerantreturn outlet pipe 43 is a refrigerant pipe that sends the refrigerant from the outlet of therefrigerant cooler 45 on the side of therefrigerant return pipe 41 to thesuction refrigerant pipe 31. Therefrigerant cooler 45 cools the refrigerant flowing through the outdoor liquid-refrigerant pipe 34 by using the refrigerant flowing through therefrigerant return pipe 41. - The
outdoor unit 2 is provided with various sensors. To be specific, theoutdoor unit 2 is provided with adischarge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from thecompressor 21. In addition, theoutdoor unit 2 is provided with an outdoor heat-exchange liquid-side sensor 37 that detects a temperature Tol (outdoor heat-exchange outlet temperature Tol) of the refrigerant on the liquid side of theoutdoor heat exchanger 23, and is provided with a liquid-pipe temperature sensor 38 that detects a temperature (liquid-pipe temperature Tlp) of the refrigerant in a portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26. - The external
shutoff valve units shutoff valve units indoor units shutoff valve units refrigerant connection pipe 6, are provided between theindoor units outdoor unit 2, and constitute part of therefrigerant circuit 10. - Configurations of the external
shutoff valve units shutoff valve unit 4 a and the externalshutoff valve unit 4 b have configurations similar to each other. Hence only the configuration of the externalshutoff valve unit 4 a is described. For the configuration of the externalshutoff valve unit 4 b, the description of the components of the externalshutoff valve unit 4 b is omitted while an index “b” is applied to each component instead of the index “a” indicating each component of the externalshutoff valve unit 4 a. - The external
shutoff valve unit 4 a is provided in the gas-refrigerant connection pipe 6, and mainly includes a gas-side shutoff valve 58 a. In addition, the externalshutoff valve unit 4 a includes agas connection pipe 62 a that is connected to the firstbranch pipe portion 6 a, which is a portion of the gas-refrigerant connection pipe 6 on the side of theoutdoor unit 2, and that is connected to the secondbranch pipe portion 6 aa, which is a portion of the gas-refrigerant connection pipe 6 on the side of theindoor unit 3 a. - The gas-
side shutoff valve 58 a is an electric expansion valve that shuts off the flow of the refrigerant that is circulated between theindoor unit 3 a and theoutdoor unit 2 via the gas-refrigerant connection pipe 6. The gas-side shutoff valve 58 a is provided in thegas connection pipe 62 a. That is, the gas-side shutoff valve 58 a is connected to the gas side of theindoor heat exchanger 52 a via the indoor gas-refrigerant pipe 54 a of theindoor unit 3 a, the secondbranch pipe portion 6 aa of the gas-refrigerant connection pipe 6, and thegas connection pipe 62 a of the externalshutoff valve unit 4 a. The gas-side shutoff valve 58 a may not be an electric expansion valve and may be an electromagnetic valve. - The
gas connection pipe 62 a mainly includes an indoor-sidegas connection pipe 66 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of theindoor unit 3 a (in this case, the secondbranch pipe portion 6 aa), and an outdoor-sidegas connection pipe 67 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, the firstbranch pipe portion 6 a). The gas-side shutoff valve 58 a is connected to the indoor-sidegas connection pipe 66 a by brazing (the brazing portion is referred to as brazingportion 91 a). The gas-side shutoff valve 58 a is connected to the outdoor-sidegas connection pipe 67 a by brazing (the brazing portion is referred to as brazingportion 92 a). The indoor-sidegas connection pipe 66 a is connected to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 95 a). The pipejoint portion 95 a is connected to the indoor-sidegas connection pipe 66 a by brazing (the brazing portion is referred to as brazing portion 95 aa). Although not illustrated here, the indoor-sidegas connection pipe 66 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa) by brazing. - The outdoor-side
gas connection pipe 67 a is connected to the gas-refrigerant connection pipe 6 (in this case, the firstbranch pipe portion 6 a) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 96 a). The pipejoint portion 96 a is connected to the outdoor-sidegas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 96 aa). Although not illustrated here, the outdoor-sidegas connection pipe 67 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, the firstbranch pipe portion 6 a) by brazing. - The
control unit 19 is constituted by being connected to control boards or the like (not illustrated) provided in, for example, theoutdoor unit 2 and theindoor units FIG. 1 , however, thecontrol unit 19 is illustrated at a position separated from theoutdoor unit 2, theindoor units shutoff valve units control unit 19 controls thecomponents outdoor unit 2, theindoor units shutoff valve units various sensors - The operation of the air conditioner 1 when the refrigerant does not leak is described next with reference to
FIG. 1 . The air conditioner 1 performs cooling operation and heating operation. The air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 provided in the outdoor liquid-refrigerant pipe 34 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units control unit 19 that controls the components of the air conditioner 1. - In cooling operation, for example, when all the
indoor units indoor heat exchangers outdoor heat exchanger 23 functions as the radiator of the refrigerant), theswitching mechanism 22 is switched to the outdoor radiation state (the state in which theswitching mechanism 22 is indicated by solid lines inFIG. 1 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans - Then, the high-pressure refrigerant discharged from the
compressor 21 is sent to theoutdoor heat exchanger 23 via theswitching mechanism 22. The refrigerant sent to theoutdoor heat exchanger 23 is condensed by being cooled through heat exchange with the outdoor air supplied by theoutdoor fan 24 in theoutdoor heat exchanger 23 that functions as the radiator of the refrigerant. The refrigerant flows out from theoutdoor unit 2 via theoutdoor expansion valve 25, therefrigerant cooler 45, the liquid-pressureadjustment expansion valve 26, and the liquid-side shutoff valve 27. - The refrigerant flowing out from the
outdoor unit 2 is branched and sent to theindoor units refrigerant connection pipe 5. The refrigerant sent to theindoor units indoor expansion valves indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor units indoor heat exchangers - The refrigerant flowing out from the
indoor units shutoff valve units branch pipe portions 6 aa and 6 bb of the gas-refrigerant connection pipe 6. The refrigerant sent to the externalshutoff valve units side shutoff valves shutoff valve units - The refrigerant flowing out from the external
shutoff valve units refrigerant connection pipe 6 and sent to theoutdoor unit 2. The refrigerant sent to theoutdoor unit 2 is sucked into thecompressor 21 via the gas-side shutoff valve 28 and theswitching mechanism 22. - In the above-described cooling operation, the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-
refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units refrigerant pipe 34 is cooled by therefrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26, so that the two-phase refrigerant feed can be properly performed. - First, the
control unit 19 causes the liquid-pressureadjustment expansion valve 26 to decompress the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into the gas-liquid two-phase state. The refrigerant decompressed by the liquid-pressureadjustment expansion valve 26 is the refrigerant at medium pressure that is lower than the pressure of the high-pressure refrigerant and higher than the pressure of the low-pressure refrigerant. Thecontrol unit 19 controls the opening degree of the liquid-pressureadjustment expansion valve 26 so that a degree of subcooling SCo of the refrigerant on the liquid side of theoutdoor heat exchanger 23 becomes a target degree of subcooling SCot. To be specific, thecontrol unit 19 obtains the degree of subcooling SCo of the refrigerant on the liquid side of theoutdoor heat exchanger 23 from the outdoor heat-exchange liquid-side temperature Tol. Thecontrol unit 19 obtains the degree of subcooling SCo of the refrigerant on the liquid side of theoutdoor heat exchanger 23 by subtracting the outdoor heat-exchange outlet temperature Tol from a temperature Toc of the refrigerant, which is obtained by converting the discharge pressure Pd into a saturation temperature. Thecontrol unit 19 performs control to increase the opening degree of the liquid-pressureadjustment expansion valve 26 if the degree of subcooling SCo is larger than the target degree of subcooling SCot, and performs control to decrease the opening degree of the liquid-pressureadjustment expansion valve 26 if the degree of subcooling SCo is smaller than the target degree of subcooling SCot. At this time, thecontrol unit 19 performs control to fix the opening degree of theoutdoor expansion valve 25 to a fully opened state. - With this control, the refrigerant flowing through the liquid-
refrigerant connection pipe 5 is brought into the gas-liquid two-phase state. Hence, the liquid-refrigerant connection pipe 5 is less likely filled with the refrigerant in the liquid state as compared with the case where the refrigerant flowing through the liquid-refrigerant connection pipe 5 is in the liquid state. The amount of refrigerant existing in the liquid-refrigerant connection pipe 5 can be decreased by that amount. - The
control unit 19 causes the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26 to be constant by cooling the refrigerant flowing through the portion of the outdoor liquid-refrigerant pipe 34 nearer to theoutdoor heat exchanger 23 than the liquid-pressureadjustment expansion valve 26 by therefrigerant cooler 45 by using the refrigerant flowing through therefrigerant return pipe 41. Thecontrol unit 19 controls the opening degree of the refrigerantreturn expansion valve 44 so that the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26 becomes a target liquid-pipe temperature Tlpt. To be specific, thecontrol unit 19 performs control to increase the opening degree of the refrigerantreturn expansion valve 44 if the liquid-pipe temperature Tlp is higher than the target liquid-pipe temperature Tlpt, and performs control to decrease the opening degree of the refrigerantreturn expansion valve 44 if the liquid-pipe temperature Tlp is lower than the target liquid-pipe temperature Tlpt. - With the control, the temperature (the liquid-pipe temperature Tlp) of the refrigerant in the portion of the outdoor liquid-
refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26 can be maintained constant at the target liquid-pipe temperature Tlpt. By making the liquid-pipe temperature Tlp constant and reducing variation, the refrigerant flowing through the liquid-refrigerant connection pipe 5 after decompressed by the liquid-pressureadjustment expansion valve 26 can be reliably maintained in a desirable gas-liquid two-phase state. - In heating operation, for example, when all the
indoor units indoor heat exchangers outdoor heat exchanger 23 functions as the evaporator of the refrigerant), theswitching mechanism 22 is switched to the outdoor evaporation state (the state in which theswitching mechanism 22 is indicated by broken lines inFIG. 1 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans - Then, the high-pressure refrigerant discharged from the
compressor 21 flows out from theoutdoor unit 2 via theswitching mechanism 22 and the gas-side shutoff valve 28. - The refrigerant flowing out from the
outdoor unit 2 is branched and sent to the externalshutoff valve units refrigerant connection pipe 6. The refrigerant sent to the externalshutoff valve units side shutoff valves shutoff valve units - The refrigerant flowing out from the external
shutoff valve units indoor units branch pipe portions 6 aa and 6 bb of the gas-refrigerant connection pipe 6. The refrigerant sent to theindoor units indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor units indoor expansion valves indoor heat exchangers - The refrigerant flowing out from the
indoor units refrigerant connection pipe 5 and sent to theoutdoor unit 2. The refrigerant sent to theoutdoor unit 2 is sent to theoutdoor expansion valve 25 via the liquid-side shutoff valve 27, the liquid-pressureadjustment expansion valve 26, and therefrigerant cooler 45. The refrigerant sent to theoutdoor expansion valve 25 is decompressed by theoutdoor expansion valve 25 to be at low pressure and then is sent to theoutdoor heat exchanger 23. The refrigerant sent to theoutdoor heat exchanger 23 is evaporated by being heated through heat exchange with the outdoor air supplied by theoutdoor fan 24. The refrigerant is sucked into thecompressor 21 via theswitching mechanism 22. - In the above-described heating operation, unlike cooling operation, the
control unit 19 performs control to fix the opening degree of the liquid-pressureadjustment expansion valve 26 to a fully opened state. The opening degree of the refrigerantreturn expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to therefrigerant return pipe 41. - The operation of the air conditioner 1 when the refrigerant leaks is described next with reference to
FIGS. 1 to 3 .FIG. 3 is a flowchart of an operation when a refrigerant leaks in the air conditioner 1 according to one or more embodiments of the present invention. The operation of the air conditioner 1 when the refrigerant leaks which is described below is performed by thecontrol unit 19 that controls the components of the air conditioner 1 (theoutdoor unit 2, theindoor units shutoff valve units - The air conditioner 1 is provided with the
refrigerant sensors refrigerant sensors indoor expansion valves side shutoff valves refrigerant sensors indoor units refrigerant connection pipes indoor units indoor expansion valves side shutoff valves indoor units - To be specific, when the
refrigerant sensors control unit 19 closes theindoor expansion valves side shutoff valves indoor expansion valves side shutoff valves compressor 21 may be stopped (step ST3) to suppress an excessive increase in the pressure of the refrigerant. - In this way, the
indoor expansion valves side shutoff valves refrigerant sensors refrigerant connection pipes indoor units - The air conditioner 1 and the
indoor units - To add the refrigerant shutoff function for the situation in which the refrigerant leaks from the
indoor units indoor units indoor units indoor units indoor expansion valves indoor units - In the
indoor units refrigerant pipes indoor expansion valves refrigerant connection pipe 5 are connected to theindoor expansion valves brazing portions indoor expansion valves refrigerant pipes brazing portions refrigerant connection pipe 5 to thebrazing portions indoor expansion valves indoor units indoor units indoor expansion valves indoor units brazing portions - In this case, by providing the
coating materials brazing portions brazing portions indoor expansion valves indoor units indoor expansion valves indoor units indoor units - Accordingly, the refrigerant shutoff function for the situation in which the refrigerant leaks from the
indoor units indoor units indoor units - In particular, since the gas-
side shutoff valves shutoff valve units indoor units indoor units - Since the
outdoor unit 2 includes the liquid-pressureadjustment expansion valve 26 as described above, the two-phase refrigerant feed of decompressing the refrigerant to be brought into the gas-liquid two-phase state in theoutdoor unit 2 and then sending the refrigerant to theindoor units refrigerant connection pipe 5 can be performed. Thus, the amount of refrigerant held by the entire air conditioner can be decreased by the amount by which the refrigerant flowing through the liquid-refrigerant connection pipe 5 turns into the gas-liquid two-phase state through the two-phase refrigerant feed. However, although the amount of refrigerant held by the entire air conditioner can be decreased by a certain degree through the two-phase refrigerant feed, when the refrigerant leaks from theindoor units indoor units - In this case, by providing the
coating materials brazing portions brazing portions indoor expansion valves indoor units - Accordingly, even in the case where the two-phase refrigerant feed is not sufficient for the countermeasure to leakage of the refrigerant, the refrigerant shutoff function for the situation in which the refrigerant leaks from the
indoor units indoor units indoor units - In one or more embodiments, only the
indoor expansion valves refrigerant pipes FIG. 2 in theindoor units indoor expansion valves refrigerant pipes FIG. 4 in theindoor units filters refrigerant pipes refrigerant pipes refrigerant pipes indoor expansion valves refrigerant pipes branch pipe portions filters refrigerant pipes refrigerant pipes filters refrigerant pipes refrigerant pipes portions brazing portions indoor expansion valves indoor units brazing portions indoor expansion valves refrigerant pipes refrigerant pipes - To address this, as illustrated in
FIG. 4 , thebrazing portions filters refrigerant pipes refrigerant pipes coating materials refrigerant pipes brazing portions brazing portions coating materials refrigerant pipes brazing portions coating materials refrigerant pipes branch pipe portion 5 a) by brazing, thecoating materials refrigerant pipes branch pipe portion 5 a). The way of providing the coating materials is not limited to the above. A coating material may be provided at each of thebrazing portions brazing portions filters brazing portions filters refrigerant pipes refrigerant pipes indoor expansion valves indoor units - Even in the case where the
filters refrigerant pipes indoor units indoor units indoor units - In the external
shutoff valve units side shutoff valves gas connection pipes gas connection pipes gas connection pipes brazing portions side shutoff valves gas connection pipes shutoff valve units brazing portions shutoff valve units indoor units brazing portions refrigerant connection pipe 6 to thebrazing portions side shutoff valves shutoff valve units brazing portions - To address this, as illustrated in
FIG. 5 , thebrazing portions side shutoff valves gas connection pipes coating materials coating materials brazing portions brazing portions FIG. 5 , thecoating materials side shutoff valves joint portions gas connection pipes brazing portions gas connection pipes branch pipe portions coating materials side shutoff valves gas connection pipes branch pipe portions brazing portions side shutoff valves gas connection pipes shutoff valve units indoor units FIG. 5 , in the configuration of one or more embodiments (seeFIG. 2 ) without thefilters brazing portions side shutoff valves gas connection pipes coating materials FIG. 4 ) with thefilters brazing portions side shutoff valves gas connection pipes coating materials - Accordingly, the degree of freedom is ensured for arrangement of the external
shutoff valve units - In one or more embodiments, to add the refrigerant shutoff function for the situation in which the refrigerant leaks from the
indoor units indoor expansion valves indoor units side shutoff valves shutoff valve units side shutoff valves indoor units FIG. 6 instead of providing the gas-side shutoff valves shutoff valve units refrigerant pipes refrigerant pipes indoor heat exchangers side shutoff valves refrigerant pipes side shutoff valves branch pipe portions refrigerant pipes side shutoff valves portions side shutoff valves refrigerant pipes portions brazing portions side shutoff valves refrigerant pipes brazing portions refrigerant connection pipe 6 to thebrazing portions side shutoff valves indoor units brazing portions - To address this, as illustrated in
FIG. 7 , thebrazing portions side shutoff valves refrigerant pipes coating materials coating materials brazing portions brazing portions FIG. 7 , thecoating materials side shutoff valves joint portions refrigerant pipes brazing portions refrigerant pipes branch pipe portions coating materials side shutoff valves refrigerant pipes branch pipe portions brazing portions side shutoff valves refrigerant pipes FIG. 7 , in the configuration of one or more embodiments (seeFIG. 2 ) without thefilters side shutoff valves indoor units brazing portions side shutoff valves refrigerant pipes coating materials FIG. 4 ) with thefilters side shutoff valves indoor unit brazing portions side shutoff valves refrigerant pipes coating materials - Accordingly, the shutoff valves provided at the
indoor units indoor units - In one or more embodiments, as illustrated in
FIG. 3 , when therefrigerant sensors indoor expansion valves side shutoff valves compressor 21 is stopped in accordance with the information of therefrigerant sensors refrigerant circuit 10 is stopped, and the cooling operation or heating operation is stopped not only in the indoor unit in which the refrigerant leaks but also in the indoor unit in which the refrigerant does not leak. - It is desirable that only the indoor unit in which the refrigerant leaks is isolated whereas the indoor unit in which the refrigerant does not leak can continue cooling operation or heating operation.
- As illustrated in
FIG. 8 , when therefrigerant sensors control unit 19 closes only the indoor expansion valve and the gas-side shutoff valve corresponding to the indoor unit in which the refrigerant leaks among a plurality ofindoor units refrigerant circuit 10 without stopping thecompressor 21, the cooling operation or heating operation of the indoor unit in which the refrigerant does not leak is continued (step ST6). - When the refrigerant leaks from the
indoor units - In one or more embodiments, when the gas-
side shutoff valves shutoff valve units indoor units shutoff valve units side shutoff valves -
FIG. 9 is a schematic configuration diagram of an air conditioner 1 according to one or more embodiments of the present invention.FIG. 10 illustrates a refrigerant system in the periphery ofindoor units relay units - The air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air-conditioning target space in a building or the like through a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an
outdoor unit 2; a plurality of (in this case, four)indoor units relay units indoor units refrigerant connection pipe 5 and a gas-refrigerant connection pipe 6 that connect theoutdoor unit 2 to theindoor units relay units control unit 19 that controls components of theoutdoor unit 2, theindoor units relay units compression refrigerant circuit 10 of the air conditioner 1 is constituted by connecting theoutdoor unit 2, the plurality ofindoor units relay units refrigerant connection pipe 5, and the gas-refrigerant connection pipe 6. Therefrigerant circuit 10 is filled with a refrigerant such as R32. In the air conditioner 1, theindoor units relay units - The liquid-
refrigerant connection pipe 5 mainly includes a joint pipe portion extending from theoutdoor unit 2, firstbranch pipe portions relay units branch pipe portions 5 aa, 5 bb, 5 cc, and 5 dd that connect therelay units indoor units - The gas-
refrigerant connection pipe 6 mainly includes a high/low-pressure gas-refrigerant connection pipe 7, a low-pressure gas-refrigerant connection pipe 8, andbranch pipe portions relay units indoor units refrigerant connection pipe 7 is a gas-refrigerant connection pipe that can switch connection to the discharge side or the suction side of a compressor 21 (described later), and includes a joint pipe portion extending from theoutdoor unit 2, and a plurality of (in this case, four)branch pipe portions relay units refrigerant connection pipe 8 is a gas-refrigerant connection pipe connected to the suction side of the compressor 21 (described later), and includes a joint pipe portion extending from theoutdoor unit 2, andbranch pipe portions relay units refrigerant connection pipe 6 includes the high/low-pressure gas-refrigerant connection pipe 7 and the low-pressure gas-refrigerant connection pipe 8, the configuration includes three connection pipes including the liquid-refrigerant connection pipe 5 (that is, three-pipe configuration). - The
indoor units indoor units indoor units indoor units indoor units outdoor unit 2 via the liquid-refrigerant connection pipe 5, the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7, the low-pressure gas-refrigerant connection pipe 8, and thebranch pipe portions relay units refrigerant circuit 10 as described above. - Configurations of the
indoor units indoor unit 3 a and theindoor units indoor unit 3 a is described. For the configurations of theindoor units indoor units indoor unit 3 a. - The
indoor unit 3 a mainly includes anindoor expansion valve 51 a and anindoor heat exchanger 52 a. In addition, theindoor unit 3 a includes an indoor liquid-refrigerant pipe 53 a that connects the liquid side of theindoor heat exchanger 52 a to the liquid-refrigerant connection pipe 5 (in this case, thebranch pipe portion 5 a), and an indoor gas-refrigerant pipe 54 a that connects the gas side of theindoor heat exchanger 52 a to the gas-refrigerant connection pipe 6 (in this case, the secondbranch pipe portion 6 aa). Theindoor expansion valve 51 a, theindoor heat exchanger 52 a, the indoor liquid-refrigerant pipe 53 a, and the indoor gas-refrigerant pipe 54 a are similar to theindoor expansion valve 51 a, theindoor heat exchanger 52 a, the indoor liquid-refrigerant pipe 53 a, and the indoor gas-refrigerant pipe 54 a of theindoor unit 3 a according to one or more embodiments. Thus, the description thereof is omitted. - A brazing
portion 82 a brazing theindoor expansion valve 51 a and a connection-side indoor liquid-refrigerant pipe 72 a is provided with acoating material 11 a, like theindoor unit 3 a according to one or more embodiments. - The
indoor unit 3 a is provided with arefrigerant sensor 57 a serving as refrigerant leakage detecting means for detecting leakage of the refrigerant, like theindoor unit 3 a according to one or more embodiments. - The
outdoor unit 2 is arranged outside the air-conditioning target spaces or outside the building or the like. Theoutdoor unit 2 is connected to theindoor units refrigerant connection pipe 5, the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7, the low-pressure gas-refrigerant connection pipe 8, and thebranch pipe portions relay units refrigerant circuit 10 as described above. - A configuration of the
outdoor unit 2 is described next. - The
outdoor unit 2 mainly includes acompressor 21 and at least one, in this case, twooutdoor heat exchangers compressor 21 is similar to thecompressor 21 of theoutdoor unit 2 according to one or more embodiments, and hence the description thereof is omitted. In addition, theoutdoor unit 2 includes switchingmechanisms outdoor heat exchangers outdoor heat exchangers mechanisms compressor 21 via asuction refrigerant pipe 31. The discharge side of thecompressor 21 is connected to the switchingmechanisms 22 a and 2 b via adischarge refrigerant pipe 32. Theswitching mechanism 22 a is connected to the gas-side ends of theoutdoor heat exchangers refrigerant pipes outdoor heat exchangers refrigerant connection pipe 5 via an outdoor liquid-refrigerant pipe 34. The connection portion of the outdoor liquid-refrigerant pipe 34 with respect to the liquid-refrigerant connection pipe 5 is provided with a liquid-side shutoff valve 27. In addition, theoutdoor unit 2 includes athird switching mechanism 22 c that switches the operating state between a refrigerant lead-out state in which the refrigerant discharged from thecompressor 21 is sent to the high/low-pressure gas-refrigerant connection pipe 7, and a refrigerant lead-in state in which the refrigerant flowing through the high/low-pressure gas-refrigerant connection pipe 7 is sent to thesuction refrigerant pipe 31. Thethird switching mechanism 22 c is connected to the high/low-pressure gas-refrigerant connection pipe 7 via a second outdoor gas-refrigerant pipe 35. Thethird switching mechanism 22 c is connected to the suction side of thecompressor 21 via thesuction refrigerant pipe 31. The discharge side of thecompressor 21 is connected to thethird switching mechanism 22 c via thedischarge refrigerant pipe 32. The connection portion of the second outdoor gas-refrigerant pipe 35 with respect to the high/low-pressure gas-refrigerant connection pipe 7 is provided with a high/low-pressure gas-side shutoff valve 28 a. Thesuction refrigerant pipe 31 is connected to the low-pressure gas-refrigerant connection pipe 8. The connection portion of thesuction refrigerant pipe 31 with respect to the low-pressure gas-refrigerant connection pipe 8 is provided with a low-pressure gas-side shutoff valve 28 b. The liquid-side shutoff valve 27 and the gas-side shutoff valves - The
first switching mechanism 22 a is a device that can switch the flow of the refrigerant in therefrigerant circuit 10 such that, when the firstoutdoor heat exchanger 23 a functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), thefirst switching mechanism 22 a connects the discharge side of thecompressor 21 to the gas side of the firstoutdoor heat exchanger 23 a (see solid lines of thefirst switching mechanism 22 a inFIG. 9 ); and, when the firstoutdoor heat exchanger 23 a functions as the evaporator of the refrigerant (hereinafter, the situation is referred to as “outdoor evaporation state”), thefirst switching mechanism 22 a connects the suction side of thecompressor 21 to the gas side of the firstoutdoor heat exchanger 23 a (see broken lines of thefirst switching mechanism 22 a inFIG. 9 ). Thefirst switching mechanism 22 a is, for example, a four-way switching valve. Thesecond switching mechanism 22 b is a device that can switch the flow of the refrigerant in therefrigerant circuit 10 such that, when the secondoutdoor heat exchanger 23 b functions as the radiator of the refrigerant (hereinafter, the situation is referred to as “outdoor radiation state”), thesecond switching mechanism 22 b connects the discharge side of thecompressor 21 to the gas side of the secondoutdoor heat exchanger 23 b (see solid lines of thesecond switching mechanism 22 b inFIG. 9 ); and, when the secondoutdoor heat exchanger 23 b functions as the evaporator of the refrigerant (hereinafter, the situation is referred to as “outdoor evaporation state”), thesecond switching mechanism 22 b connects the suction side of thecompressor 21 to the gas side of the secondoutdoor heat exchanger 23 b (see broken lines of theswitching mechanism 22 inFIG. 9 ). Thesecond switching mechanism 22 b is, for example, a four-way switching valve. By changing the switching states of the switchingmechanisms outdoor heat exchangers - The first
outdoor heat exchanger 23 a and the secondoutdoor heat exchanger 23 b are heat exchangers that exchange heat between the refrigerant, which is circulated among theoutdoor unit 2 and theindoor units refrigerant connection pipe 5 and the gas-refrigerant connection pipe 6, and the outdoor air. Theoutdoor unit 2 includes anoutdoor fan 24 that sucks the outdoor air into theoutdoor unit 2, that causes the outdoor air to exchange heat with the refrigerant in theoutdoor heat exchangers outdoor unit 2 includes theoutdoor fan 24 as a fan that sends the outdoor air, which serves as a cooling source or a heating source of the refrigerant flowing through theoutdoor heat exchangers outdoor heat exchangers outdoor fan 24 is driven by an outdoor fan motor 24 a. - The
third switching mechanism 22 c is a device that can switch the flow of the refrigerant in therefrigerant circuit 10 such that, when the refrigerant discharged from thecompressor 21 is sent to the high/low-pressure gas-refrigerant connection pipe 7 (hereinafter, the situation is referred to as “refrigerant lead-out state”), thethird switching mechanism 22 c connects the discharge side of thecompressor 21 to the high/low-pressure gas-refrigerant connection pipe 7 (see broken lines of thethird switching mechanism 22 c inFIG. 9 ); and, when the refrigerant flowing through the high/low-pressure gas-refrigerant connection pipe 7 is sent to the suction refrigerant pipe 31 (hereinafter, the situation is referred to as “refrigerant lead-in state”), thethird switching mechanism 22 c connects the suction side of thecompressor 21 to the high/low-pressure gas-refrigerant connection pipe 7 (see solid lines of thethird switching mechanism 22 c inFIG. 9 ). Thethird switching mechanism 22 c is, for example, a four-way switching valve. - Focusing on the
outdoor heat exchangers refrigerant connection pipe 5, therelay units indoor heat exchangers outdoor heat exchangers refrigerant connection pipe 5 and therelay units indoor heat exchangers compressor 21, the gas-refrigerant connection pipe 6, therelay units indoor heat exchangers compressor 21, via the gas-refrigerant connection pipe 6 and therelay units indoor heat exchangers mechanisms outdoor heat exchangers outdoor unit 2 to theindoor units refrigerant connection pipe 5 and therelay units mechanisms third switching mechanism 22 c is switched to the refrigerant lead-out state. In this state, theoutdoor heat exchangers indoor units outdoor unit 2 via the liquid-refrigerant connection pipe 5 and therelay units - In addition,
outdoor expansion valves adjustment expansion valve 26 are provided in the outdoor liquid-refrigerant pipe 34. Theoutdoor expansion valves refrigerant pipe 34 near the liquid sides of theoutdoor heat exchangers adjustment expansion valve 26 is an electric expansion valve that decompresses the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into a gas-liquid two-phase state in cooling only operation and cooling main operation, and is provided in a portion of the outdoor liquid-refrigerant pipe 34 near the liquid-refrigerant connection pipe 5. That is, the liquid-pressureadjustment expansion valve 26 is provided in a portion of the outdoor liquid-refrigerant pipe 34 nearer to the liquid-refrigerant connection pipe 5 than theoutdoor expansion valves - The air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-
refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units - Furthermore, a
refrigerant return pipe 41 is connected to the outdoor liquid-refrigerant pipe 34, and arefrigerant cooler 45 is provided. Therefrigerant return pipe 41 and therefrigerant cooler 45 are similar to therefrigerant return pipe 41 and therefrigerant cooler 45 of theoutdoor unit 2 according to one or more embodiments, and hence the description thereof is omitted. - The
outdoor unit 2 is provided with various sensors. To be specific, theoutdoor unit 2 is provided with adischarge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from thecompressor 21. In addition, theoutdoor unit 2 is provided with outdoor heat-exchange liquid-side sensors outdoor heat exchangers pipe temperature sensor 38 that detects a temperature (liquid-pipe temperature Tlp) of the refrigerant in a portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26. - The
relay units relay units indoor units relay units indoor units outdoor unit 2, together with the liquid-refrigerant connection pipe 5, the gas-refrigerant connection pipe 6 (the high/low-pressure gas-refrigerant connection pipe 7, the low-pressure gas-refrigerant connection pipe 8, and thebranch pipe portions refrigerant circuit 10. - Configurations of the
relay units relay unit 4 a and therelay units relay unit 4 a is described. For the configurations of therelay units relay units relay unit 4 a. - The
relay unit 4 a mainly includes aliquid connection pipe 61 a and agas connection pipe 62 a. - One end of the
liquid connection pipe 61 a is connected to the firstbranch pipe portion 5 a of the liquid-refrigerant connection pipe 5. The other end of theliquid connection pipe 61 a is connected to the secondbranch pipe portion 5 aa of the liquid-refrigerant connection pipe 5. - The
liquid connection pipe 61 a is connected to a portion of the liquid-refrigerant connection pipe 5 on the side of theindoor unit 3 a (in this case, the secondbranch pipe portion 5 aa) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 98 a). The pipejoint portion 98 a is connected to theliquid connection pipe 61 a by brazing (the brazing portion is referred to as brazing portion 98 aa). Although not illustrated here, theliquid connection pipe 61 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, the secondbranch pipe portion 5 aa) by brazing. Theliquid connection pipe 61 a is connected to a portion of the liquid-refrigerant connection pipe 5 on the side of the outdoor unit 2 (in this case, the firstbranch pipe portion 5 a) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 99 a). The pipejoint portion 99 a is connected to theliquid connection pipe 61 a by brazing (the brazing portion is referred to as brazing portion 99 aa). Although not illustrated here, theliquid connection pipe 61 a may be directly connected to the liquid-refrigerant connection pipe 5 (in this case, the firstbranch pipe portion 5 a) by brazing. - The
gas connection pipe 62 a includes a high-pressuregas connection pipe 63 a connected to thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7, a low-pressuregas connection pipe 64 a connected to thebranch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8, and a jointgas connection pipe 65 a that joins the high-pressuregas connection pipe 63 a and the low-pressuregas connection pipe 64 a together. The jointgas connection pipe 65 a is connected to thebranch pipe portion 6 a of the gas-refrigerant connection pipe 6. The high-pressuregas connection pipe 63 a is provided with a first cooling/heating switching valve 58 a. The low-pressuregas connection pipe 64 a is provided with a second cooling/heating switching valve 59 a. The first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a are electric expansion valves. The first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a may not be electric expansion valves and may be electromagnetic valves. - The
relay unit 4 a can function such that, when theindoor unit 3 a performs cooling operation, the second cooling/heating switching valve 59 a is opened to allow the refrigerant to flow into theliquid connection pipe 61 a via the firstbranch pipe portion 5 a of the liquid-refrigerant connection pipe 5, the refrigerant is sent to theindoor unit 3 a via the secondbranch pipe portion 5 aa of the liquid-refrigerant connection pipe 5, then the refrigerant evaporated through heat exchange with the indoor air in theindoor heat exchanger 52 a is recovered to thebranch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8 via thebranch pipe portion 6 a of the gas-refrigerant connection pipe 6, the jointgas connection pipe 65 a, and the low-pressuregas connection pipe 64 a. In addition, therelay unit 4 a can function such that, when theindoor unit 3 a performs heating operation, the second cooling/heating switching valve 59 a is closed and the first cooling/heating switching valve 58 a is opened to allow the refrigerant to flow into the high-pressuregas connection pipe 63 a and the jointgas connection pipe 65 a via thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7, the refrigerant is sent to theindoor unit 3 a via thebranch pipe portion 6 a of the gas-refrigerant connection pipe 6, then the refrigerant radiated through heat exchange with the indoor air in theindoor heat exchanger 52 a is recovered to the firstbranch pipe portion 5 a of the liquid-refrigerant connection pipe 5 via the secondbranch pipe portion 5 aa of the liquid-refrigerant connection pipe 5 and theliquid connection pipe 61 a. The first cooling/heating switching valve 58 a and the second cooling/heating switching valve 59 a are opened and closed through switching to cause theindoor heat exchanger 52 a to function as the evaporator of the refrigerant or the radiator of the refrigerant. Not only therelay unit 4 a but also therelay units relay units indoor heat exchangers - The high-pressure
gas connection pipe 63 a mainly includes an indoor-side high-pressuregas connection pipe 66 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of theindoor unit 3 a (in this case, thebranch pipe portion 6 a) via the jointgas connection pipe 65 a, and an outdoor-side high-pressuregas connection pipe 67 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7). The first cooling/heating switching valve 58 a is connected to the indoor-side high-pressuregas connection pipe 66 a by brazing (the brazing portion is referred to as brazingportion 91 a). The first cooling/heating switching valve 58 a is connected to the outdoor-side high-pressuregas connection pipe 67 a by brazing (the brazing portion is referred to as brazingportion 92 a). The low-pressuregas connection pipe 64 a mainly includes an indoor-side low-pressuregas connection pipe 68 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of theindoor unit 3 a (in this case, thebranch pipe portion 6 a) via the jointgas connection pipe 65 a, and an outdoor-side low-pressuregas connection pipe 69 a that is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, thebranch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8). The second cooling/heating switching valve 59 a is connected to the indoor-side low-pressuregas connection pipe 68 a by brazing (the brazing portion is referred to as brazingportion 93 a). The second cooling/heating switching valve 59 a is connected to the outdoor-side low-pressuregas connection pipe 69 a by brazing (the brazing portion is referred to as brazingportion 94 a). The jointgas connection pipe 65 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of theindoor unit 3 a (in this case, thebranch pipe portion 6 a) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 95 a). The pipejoint portion 95 a is connected to the jointgas connection pipe 65 a by brazing (the brazing portion is referred to as brazing portion 95 aa). Although not illustrated here, the jointgas connection pipe 65 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, thebranch pipe portion 6 a) by brazing. The outdoor-side high-pressuregas connection pipe 67 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 96 a). The pipejoint portion 96 a is connected to the outdoor-side high-pressuregas connection pipe 67 a by brazing (the brazing portion is referred to as brazing portion 96 aa). Although not illustrated here, the outdoor-side high-pressuregas connection pipe 67 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7) by brazing. The outdoor-side low-pressuregas connection pipe 69 a is connected to a portion of the gas-refrigerant connection pipe 6 on the side of the outdoor unit 2 (in this case, thebranch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8) by mechanical pipe joint, such as flare connection (the portion of the mechanical pipe joint is referred to as pipejoint portion 97 a). The pipejoint portion 97 a is connected to the outdoor-side low-pressuregas connection pipe 69 a by brazing (the brazing portion is referred to as brazing portion 97 aa). Although not illustrated here, the outdoor-side low-pressuregas connection pipe 69 a may be directly connected to the gas-refrigerant connection pipe 6 (in this case, thebranch pipe portion 8 a of the low-pressure gas-refrigerant connection pipe 8) by brazing. - The
control unit 19 is constituted by being connected to control boards or the like (not illustrated) provided in, for example, theoutdoor unit 2, theindoor units relay units FIG. 9 , however, thecontrol unit 19 is illustrated at a position separated from theoutdoor unit 2, theindoor units relay units control unit 19 controls thecomponents outdoor unit 2, theindoor units relay units various sensors - The operation of the air conditioner 1 when the refrigerant does not leak is described next with reference to
FIG. 9 . The air conditioner 1 performs cooling only operation, heating only operation, cooling main operation, and heating main operation. The air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 provided in the outdoor liquid-refrigerant pipe 34 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units control unit 19 that controls the components of the air conditioner 1. - In cooling only operation, for example, when all the
indoor units indoor heat exchangers outdoor heat exchangers mechanisms mechanisms FIG. 9 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans third switching mechanism 22 c is switched to the refrigerant lead-in state (the state in which theswitching mechanism 22 c is indicated by solid lines inFIG. 9 ), and the first cooling/heating switching valves heating switching valves relay units - Then, the high-pressure refrigerant discharged from the
compressor 21 is sent to theoutdoor heat exchangers mechanisms outdoor heat exchangers outdoor fan 24 in theoutdoor heat exchangers outdoor unit 2 via theoutdoor expansion valves refrigerant cooler 45, the liquid-pressureadjustment expansion valve 26, and the liquid-side shutoff valve 27. - The refrigerant flowing out from the
outdoor unit 2 is branched and sent to therelay units branch pipe portions relay units indoor units indoor units indoor expansion valves indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor units indoor heat exchangers - The refrigerant flowing out from the
indoor units relay units branch pipe portions refrigerant connection pipe 6. The refrigerant sent to therelay units relay units heating switching valves heating switching valves - The refrigerant flowing out from the
relay units outdoor unit 2 via the high/low-pressure gas-refrigerant connection pipe 7 (the joint pipe portion and thebranch pipe portions branch pipe portions outdoor unit 2 is sucked into thecompressor 21 via the gas-side shutoff valves third switching mechanism 22 c. - In the above-described cooling only operation, the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-
refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units refrigerant pipe 34 is cooled by therefrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26, so that the two-phase refrigerant feed can be properly performed. The control content relating to the two-phase refrigerant feed is similar to the control content relating to the two-phase refrigerant feed by the air conditioner 1 according to one or more embodiments, and hence the description thereof is omitted. With this control, the refrigerant flowing through the liquid-refrigerant connection pipe 5 is brought into the gas-liquid two-phase state. Hence, the liquid-refrigerant connection pipe 5 is less likely filled with the refrigerant in the liquid state as compared with the case where the refrigerant flowing through the liquid-refrigerant connection pipe 5 is in the liquid state. The amount of refrigerant existing in the liquid-refrigerant connection pipe 5 can be decreased by that amount. By making the liquid-pipe temperature Tlp constant and reducing variation, the refrigerant flowing through the liquid-refrigerant connection pipe 5 after decompressed by the liquid-pressureadjustment expansion valve 26 can be reliably maintained in a desirable gas-liquid two-phase state. - In heating only operation, for example, when all the
indoor units indoor heat exchangers outdoor heat exchangers mechanisms mechanisms FIG. 9 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which theswitching mechanism 22 c is indicated by broken lines inFIG. 9 ), and the first cooling/heating switching valves heating switching valves relay units - Then, the high-pressure refrigerant discharged from the
compressor 21 flows out from theoutdoor unit 2 via thethird switching mechanism 22 c and the gas-side shutoff valve 28 a. - The refrigerant flowing out from the
outdoor unit 2 is branched and sent to therelay units branch pipe portions relay units relay units heating switching valves - The refrigerant flowing out from the
relay units indoor units branch pipe portions refrigerant connection pipe 6 connecting therelay units indoor units indoor units indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor expansion valves indoor units indoor heat exchangers - The refrigerant flowing out from the
indoor units relay units branch pipe portions 5 aa, 5 bb, 5 cc, and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting therelay units indoor units relay units relay units - The refrigerant flowing out from the
relay units outdoor unit 2 via the liquid-refrigerant connection pipe 5 (the joint pipe portion and the firstbranch pipe portions outdoor unit 2 is sent to theoutdoor expansion valves side shutoff valve 27 and therefrigerant cooler 45. The refrigerant sent to theoutdoor expansion valves outdoor expansion valves outdoor heat exchangers outdoor heat exchangers outdoor fan 24. The refrigerant is sucked into thecompressor 21 via the switchingmechanisms - In the above-described heating only operation, unlike cooling only operation, the
control unit 19 performs control to fix the opening degree of the liquid-pressureadjustment expansion valve 26 in a fully opened state. Thus, the opening degree of the refrigerantreturn expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to therefrigerant return pipe 41. - In cooling main operation, for example, when the
indoor units indoor unit 3 a performs heating operation (that is, operation in which theindoor heat exchangers indoor heat exchanger 52 a functions as the radiator of the refrigerant), and theindoor heat exchangers mechanisms mechanisms FIG. 9 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which theswitching mechanism 22 c is indicated by broken lines inFIG. 9 ), the first cooling/heating switching valve 58 a of therelay unit 4 a and the second cooling/heating switching valves relay units heating switching valve 59 a of therelay unit 4 a as well as the first cooling/heating switching valves 58b relay units - Then, part of the high-pressure refrigerant discharged from the
compressor 21 is sent to theoutdoor heat exchangers mechanisms outdoor unit 2 via thethird switching mechanism 22 c and the gas-side shutoff valve 28 a. The refrigerant sent to theoutdoor heat exchangers outdoor fan 24 in theoutdoor heat exchangers outdoor unit 2 via theoutdoor expansion valves refrigerant cooler 45, the liquid-pressureadjustment expansion valve 26, and the liquid-side shutoff valve 27. - The refrigerant flowing out from the
outdoor unit 2 via thethird switching mechanism 22 c and so forth is sent to therelay unit 4 a via the gas-refrigerant connection pipe 6 (the joint pipe portion and thebranch pipe portion 7 a of the high/low-pressure gas-refrigerant connection pipe 7). The refrigerant sent to therelay unit 4 a flows out from therelay unit 4 a via the first cooling/heating switching valve 58 a. - The refrigerant flowing out from the
relay unit 4 a is sent to theindoor unit 3 a via thebranch pipe portion 6 a (the portion of the gas-refrigerant connection pipe 6 connecting therelay unit 4 a to theindoor unit 3 a). The refrigerant sent to theindoor unit 3 a is sent to theindoor heat exchanger 52 a. The high-pressure refrigerant sent to theindoor heat exchanger 52 a is condensed by being cooled through heat exchange with the indoor air supplied from the air-conditioning target space by theindoor fan 55 a in theindoor heat exchanger 52 a that functions as the radiator of the refrigerant. The refrigerant is decompressed by theindoor expansion valve 51 a and then flows out from theindoor unit 3 a. The indoor air heated by theindoor heat exchanger 52 a is sent to the air-conditioning target space and the air-conditioning target space is heated by using the heated indoor air. - The refrigerant flowing out from the
indoor unit 3 a is sent to therelay unit 4 a via the secondbranch pipe portion 5 aa (the portion of the liquid-refrigerant connection pipe 5 connecting therelay unit 4 a to theindoor unit 3 a). The refrigerant sent to therelay unit 4 a flows out from therelay unit 4 a. - The refrigerant flowing out from the
relay unit 4 a is sent to the joint pipe portion of the liquid-refrigerant connection pipe 5 via the firstbranch pipe portion 5 a, and is joined to the refrigerant flowing out from theoutdoor unit 2 via theoutdoor heat exchangers relay units branch pipe portions refrigerant connection pipe 5. The refrigerant sent to therelay units relay units - The refrigerant flowing out from the
relay units indoor units branch pipe portions 5 bb, 5 cc, and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting therelay units indoor units indoor units indoor expansion valves indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor units indoor heat exchangers - The refrigerant flowing out from the
indoor units relay units branch pipe portions refrigerant connection pipe 6. The refrigerant sent to therelay units relay units heating switching valves - The refrigerant flowing out from the
relay units outdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 (the joint pipe portion and thebranch pipe portions outdoor unit 2 is sucked into thecompressor 21 via the gas-side shutoff valves third switching mechanism 22 c. - In the above-described cooling main operation, like cooling only operation, the air conditioner 1 performs two-phase refrigerant feed of sending the refrigerant in the gas-liquid two-phase state to the liquid-
refrigerant connection pipe 5 by the liquid-pressureadjustment expansion valve 26 and hence sending the refrigerant from theoutdoor unit 2 to theindoor units refrigerant pipe 34 is cooled by therefrigerant return pipe 41 and the refrigerant cooler 45 to reduce variation in the liquid-pipe temperature Tlp in the portion of the outdoor liquid-refrigerant pipe 34 between therefrigerant cooler 45 and the liquid-pressureadjustment expansion valve 26, so that the two-phase refrigerant feed can be properly performed. - In heating main operation, for example, when the
indoor units indoor unit 3 a performs cooling operation (that is, operation in which theindoor heat exchangers indoor heat exchanger 52 a functions as the evaporator of the refrigerant), and theindoor heat exchangers mechanisms mechanisms FIG. 9 ), and thecompressor 21, theoutdoor fan 24, and theindoor fans third switching mechanism 22 c is switched to the refrigerant lead-out state (the state in which theswitching mechanism 22 c is indicated by broken lines inFIG. 9 ), the second cooling/heating switching valves relay units heating switching valve 59 a of therelay unit 4 a as well as the first cooling/heating switching valves 58b relay units - Then, the high-pressure refrigerant discharged from the
compressor 21 flows out from theoutdoor unit 2 via thethird switching mechanism 22 c and the gas-side shutoff valve 28 a. - The refrigerant flowing out from the
outdoor unit 2 is branched and sent to therelay units branch pipe portions relay units relay units heating switching valves - The refrigerant flowing out from the
relay units indoor units branch pipe portions refrigerant connection pipe 6 connecting therelay units indoor units indoor units indoor heat exchangers indoor heat exchangers indoor fans indoor heat exchangers indoor expansion valves indoor units indoor heat exchangers - The refrigerant flowing out from the
indoor units relay units branch pipe portions 5 bb, 5 cc, and 5 dd (the portions of the liquid-refrigerant connection pipe 5 connecting therelay units indoor units relay units relay units - The refrigerant flowing out from the
relay units branch pipe portions refrigerant connection pipe 5, part of the refrigerant is branched to the firstbranch pipe portion 5 a and sent to therelay unit 4 a, and the residual part of the refrigerant is sent to theoutdoor unit 2 via the joint pipe portion of the liquid-refrigerant connection pipe 5. The refrigerant sent to therelay unit 4 a flows out from therelay unit 4 a. - The refrigerant flowing out from the
relay unit 4 a is sent to theindoor unit 3 a via the secondbranch pipe portion 5 aa (the portion of the liquid-refrigerant connection pipe 5 connecting therelay unit 4 a to theindoor unit 3 a). The refrigerant sent to theindoor units 3 a is decompressed by theindoor expansion valve 51 a and then sent to theindoor heat exchanger 52 a. The refrigerant sent to theindoor heat exchanger 52 a is evaporated by being heated through heat exchange with the indoor air supplied from the air-conditioning target space by theindoor fan 55 a in theindoor heat exchanger 52 a that functions as the evaporator of the refrigerant. The refrigerant flows out from theindoor unit 3 a. The indoor air cooled by theindoor heat exchanger 52 a is sent to the air-conditioning target space and the air-conditioning target space is cooled by using the cooled indoor air. - The refrigerant flowing out from the
indoor unit 3 a is sent to therelay unit 4 a via thebranch pipe portion 6 a of the gas-refrigerant connection pipe 6. The refrigerant sent to therelay unit 4 a flows out from therelay unit 4 a via the second cooling/heating switching valve 59 a. - The refrigerant flowing out from the
relay unit 4 a is sent to theoutdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 (the joint pipe portion and thebranch pipe portion 8 a). The refrigerant sent to theoutdoor unit 2 via the joint pipe portion of the liquid-refrigerant connection pipe 5 is sent to theoutdoor expansion valves side shutoff valve 27, the liquid-pressureadjustment expansion valve 26, and therefrigerant cooler 45. The refrigerant sent to theoutdoor expansion valves outdoor expansion valves outdoor heat exchangers outdoor heat exchangers outdoor fan 24. The refrigerant is joined to the refrigerant sent to theoutdoor unit 2 via the low-pressure gas-refrigerant connection pipe 8 and is sucked into thecompressor 21, via the switchingmechanisms - In the above-described heating main operation, like heating only operation, the
control unit 19 performs control to fix the opening degree of the liquid-pressureadjustment expansion valve 26 in a fully opened state. Thus, the opening degree of the refrigerantreturn expansion valve 44 is brought into a fully closed state to inhibit the refrigerant from flowing to therefrigerant return pipe 41. - The operation of the air conditioner 1 when the refrigerant leaks is described next with reference to
FIGS. 9 to 11 .FIG. 11 is a flowchart of an operation when a refrigerant leaks in the air conditioner 1 according to one or more embodiments of the present invention. The operation of the air conditioner 1 which is described below is performed by thecontrol unit 19 that controls the components of the air conditioner 1 (theoutdoor unit 2, theindoor units relay units - The air conditioner 1 is provided with the
refrigerant sensors refrigerant sensors indoor expansion valves heating switching valves refrigerant sensors indoor units refrigerant connection pipes indoor units indoor expansion valves heating switching valves indoor units - To be specific, when the
refrigerant sensors control unit 19 closes theindoor expansion valves heating switching valves indoor expansion valves heating switching valves compressor 21 may be stopped (step ST3) to suppress an excessive increase in the pressure of the refrigerant. - In this way, the
indoor expansion valves heating switching valves refrigerant sensors refrigerant connection pipes indoor units - The air conditioner 1 and the
indoor units - Like the air conditioner 1 and the
indoor units indoor units brazing portions indoor expansion valves refrigerant pipes indoor expansion valves indoor units - In this case, like the air conditioner 1 and the
indoor units brazing portions coating materials brazing portions - Accordingly, like the air conditioner 1 and the
indoor units indoor units indoor units indoor units - In particular, as described above, the cooling/
heating switching valves relay units indoor units indoor heat exchangers heating switching valves indoor units indoor units - Accordingly, the refrigerant shutoff function for the situation in which the refrigerant leaks from the
indoor units indoor units indoor units - Since the
outdoor unit 2 includes the liquid-pressureadjustment expansion valve 26 like the air conditioner 1 according to one or more embodiments, the two-phase refrigerant feed of decompressing the refrigerant to be brought into the gas-liquid two-phase state in theoutdoor unit 2 and then sending the refrigerant to theindoor units refrigerant connection pipe 5 is performed. Accordingly, like the air conditioner 1 according to one or more embodiments, even in the case where the two-phase refrigerant feed is not sufficient for the countermeasure to leakage of the refrigerant, the refrigerant shutoff function for the situation in which the refrigerant leaks from theindoor units indoor units indoor units - In one or more embodiments, only the
indoor expansion valves refrigerant pipes FIG. 10 in theindoor units indoor expansion valves refrigerant pipes FIG. 12 in theindoor units filters refrigerant pipes refrigerant pipes refrigerant pipes indoor expansion valves refrigerant pipes branch pipe portions 5 aa, 5 bb, 5 cc, and 5 dd). In addition, thefilters refrigerant pipes refrigerant pipes filters refrigerant pipes refrigerant pipes portions brazing portions indoor expansion valves indoor units brazing portions indoor units - To address this, as illustrated in
FIG. 12 , thebrazing portions filters refrigerant pipes refrigerant pipes coating materials refrigerant pipes brazing portions brazing portions coating materials refrigerant pipes brazing portions coating materials refrigerant pipes branch pipe portions 5 aa, 5 bb, 5 cc, and 5 dd) by brazing, thecoating materials refrigerant pipes branch pipe portions 5 aa, 5 bb, 5 cc, and 5 dd). The way of providing the coating materials is not limited to the above-described way like theindoor units brazing portions filters refrigerant pipes refrigerant pipes indoor expansion valves indoor units - Even in the case where the
filters refrigerant pipes indoor units indoor units indoor units - In the external
shutoff valve units heating switching valves gas connection pipes gas connection pipes gas connection pipes gas connection pipes gas connection pipes brazing portions heating switching valves gas connection pipes brazing portions heating switching valves gas connection pipes relay units brazing portions relay units indoor units brazing portions refrigerant connection pipe 6 to thebrazing portions shutoff valve units heating switching valves brazing portions - To address this, as illustrated in
FIG. 13 , thebrazing portions heating switching valves gas connection pipes coating materials brazing portions heating switching valves gas connection pipes coating materials coating materials brazing portions brazing portions FIG. 13 , thecoating materials heating switching valves joint portions gas connection pipes brazing portions gas connection pipes branch pipe portions coating materials heating switching valves gas connection pipes branch pipe portions coating materials heating switching valves joint portions gas connection pipes brazing portions gas connection pipes branch pipe portions coating materials heating switching valves gas connection pipes branch pipe portions brazing portions heating switching valves gas connection pipes brazing portions heating switching valves gas connection pipes relay units indoor units FIG. 13 , in the configuration of the above-described embodiments (seeFIG. 10 ) without thefilters brazing portions heating switching valves gas connection pipes brazing portions heating switching valves gas connection pipes coating materials FIG. 12 ) with thefilters brazing portions heating switching valves gas connection pipes brazing portions heating switching valves gas connection pipes coating materials - Accordingly, the degree of freedom is ensured for arrangement of the
relay units - In the above-described embodiments, as illustrated in
FIG. 11 , when therefrigerant sensors indoor expansion valves heating switching valves compressor 21 is stopped in accordance with the information of therefrigerant sensors refrigerant circuit 10 is stopped, and the cooling operation or heating operation is stopped not only in the indoor unit in which the refrigerant leaks but also in the indoor unit in which the refrigerant does not leak. - However, it is desirable that only the indoor unit in which the refrigerant leaks is isolated whereas the indoor unit in which the refrigerant does not leak can continue cooling operation or heating operation.
- As illustrated in
FIG. 14 , when therefrigerant sensors control unit 19 closes only the indoor expansion valve and the cooling/heating switching valve corresponding to the indoor unit in which the refrigerant leaks among the plurality ofindoor units refrigerant circuit 10 without stopping thecompressor 21, the cooling operation or heating operation of the indoor unit in which the refrigerant does not leak is continued (step ST6). - When the refrigerant leaks from the
indoor units - In the above-described embodiments, the
relay units indoor units relay units relay units - The present invention can be widely applied to an air conditioner configured such that an outdoor unit and an indoor unit arranged in an air-conditioning target space are connected to each other via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe, and an indoor unit used for the air conditioner.
- 1 air conditioner
- 2 outdoor unit
- 3 a, 3 b, 3 c, 3 d indoor unit
- 4 a, 4 b, 4 c, 4 d external shutoff valve unit, relay unit
- 5 liquid-refrigerant connection pipe
- 6 gas-refrigerant connection pipe
- 11 a, 11 b, 11 c, 11 d coating material
- 12 a, 12 b, 12 c, 12 d coating material
- 13 a, 13 b, 13 c, 13 d coating material
- 14 a, 14 b, 14 c, 14 d coating material
- 15 a, 15 b coating material
- 19 control unit
- 23, 23 a, 23 b outdoor heat exchanger
- 26 liquid-pressure adjustment expansion valve
- 51 a, 51 b, 51 c, 51 d indoor expansion valve
- 52 a, 52 b, 52 c, 52 d indoor heat exchanger
- 57 a, 57 b, 57 c, 57 d refrigerant sensor (refrigerant leakage detecting means)
- 58 a, 58 b, 58 c, 58 d gas-side shutoff valve, first cooling/heating switching valve
- 59 a, 59 b, 59 c, 59 d second cooling/heating switching valve (gas-side shutoff valve)
- 66 a, 66 b, 66 c, 66 d indoor-side gas connection pipe
- 67 a, 67 b, 67 c, 67 d outdoor-side gas connection pipe
- 68 a, 68 b, 68 c, 68 d indoor-side gas connection pipe
- 69 a, 69 b, 69 c, 69 d outdoor-side gas connection pipe
- 71 a, 71 b, 71 c, 71 d heat-exchange-side indoor liquid-refrigerant pipe
- 72 a, 72 b, 72 c, 72 d connection-side indoor liquid-refrigerant pipe
- 73 a, 73 b, 73 c, 73 d filter
- 74 a, 74 b, 74 c, 74 d first connection-side indoor liquid-refrigerant pipe
- 75 a, 75 b, 75 c, 75 d second connection-side indoor liquid-refrigerant pipe
- 76 a, 76 b heat-exchange-side indoor gas-refrigerant pipe
- 77 a, 77 b connection-side indoor gas-refrigerant pipe
- 82 a, 82 b, 82 c, 82 d brazing portion
- 85 a, 85 b, 85 c, 85 d brazing portion
- 86 a, 86 b, 86 c, 86 d brazing portion
- 88 a, 88 b brazing portion
- 92 a, 92 b, 92 c, 92 d brazing portion
- 94 a, 94 b, 94 c, 94 d brazing portion
- Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.
Claims (13)
1-12. (canceled)
13. An air conditioner comprising:
an outdoor unit;
a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe;
an indoor unit that:
is connected to the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe,
is arranged in an air-conditioning target space, and
includes:
an indoor heat exchanger that performs heat exchange between:
a refrigerant circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and
air sent to the air-conditioning target space;
an indoor expansion valve that decompresses the refrigerant;
a heat-exchange-side indoor liquid-refrigerant pipe that connects a liquid side of the indoor heat exchanger to the indoor expansion valve; and
a connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe;
a gas-side shutoff valve that is connected to a gas side of the indoor heat exchanger;
a refrigerant sensor that detects leakage of the refrigerant; and
a controller, wherein
the indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing,
a coating material is disposed over brazing portions of the indoor expansion valve and the connection-side indoor liquid-refrigerant, and
the controller closes the indoor expansion valve and the gas-side shutoff valve based on information from the refrigerant sensor when leakage of the refrigerant is detected.
14. The air conditioner according to claim 13 , wherein
the connection-side indoor liquid-refrigerant pipe includes:
a first connection-side indoor liquid-refrigerant pipe connected to the indoor expansion valve;
a second connection-side indoor liquid-refrigerant pipe connected to the liquid-refrigerant connection pipe; and
a filter connected, by brazing, between the first connection-side indoor liquid-refrigerant pipe and the second connection-side indoor liquid-refrigerant pipe, and
the coating material is disposed over brazing portions of the filter, the first connection-side indoor liquid-refrigerant pipe, and the second connection-side indoor liquid-refrigerant pipe.
15. The air conditioner according to claim 13 , wherein
the outdoor unit includes an outdoor heat exchanger and a liquid-pressure adjustment expansion valve, and
when the refrigerant is sent from the outdoor heat exchanger to the indoor unit via the liquid-refrigerant connection pipe, the controller controls:
the liquid-pressure adjustment expansion valve to decompress the refrigerant flowing through the liquid-refrigerant connection pipe to be brought into a gas-liquid two-phase state, and
the indoor expansion valve to decompress the refrigerant decompressed by the liquid-pressure adjustment expansion valve.
16. The air conditioner according to claim 13 , further comprising:
a plurality of indoor units, wherein
each of the indoor units includes a corresponding gas-side shutoff valve and indoor expansion valve.
17. The air conditioner according to claim 16 wherein the controller closes only the indoor expansion valve and the gas-side shutoff valve of the indoor units where leakage of the refrigerant is detected by the refrigerant sensor.
18. The air conditioner according to claim 13 , wherein
the gas-refrigerant connection pipe includes an external shutoff valve unit including the gas-side shutoff valve.
19. The air conditioner according to claim 18 , wherein
the gas-side shutoff valve is connected, by brazing, to:
an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit; and
an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit, and
a coating material is disposed over brazing portions of the gas-side shutoff valve and the outdoor-side gas connection pipe.
20. The air conditioner according to claim 16 , wherein
each of the indoor units includes a corresponding indoor heat exchanger,
the gas-refrigerant connection pipe includes a relay including cooling/heating switching valves that individually switches the indoor heat exchanger of each of the plurality of indoor units between an evaporator or a radiator of the refrigerant,
the cooling/heating switching valve serve as the gas-side shutoff valve, and
the controller closes the indoor expansion valve and the cooling/heating switching valves where leakage of the refrigerant is detected by the refrigerant sensor.
21. The air conditioner according to claim 20 , wherein
each of the cooling/heating switching valves is connected, by brazing, to:
an indoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the indoor unit; and
an outdoor-side gas connection pipe that is connected to a portion of the gas-refrigerant connection pipe on a side of the outdoor unit, and
a coating material is disposed over brazing portions of the cooling/heating switching valves and the outdoor-side gas connection pipe.
22. The air conditioner according to claim 13 , wherein
the gas-side shutoff valve is provided in the indoor unit,
the indoor unit further includes:
a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve; and
a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe,
the gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing, and
a coating material is disposed over brazing portions of the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
23. An indoor unit connected to an outdoor unit via a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe and arranged in an air-conditioning target space, the indoor unit comprising:
an indoor heat exchanger that performs heat exchange between:
a refrigerant circulated between the indoor unit and the outdoor unit via the liquid-refrigerant connection pipe and the gas-refrigerant connection pipe, and
air sent to the air-conditioning target space;
an indoor expansion valve that decompresses the refrigerant;
a heat-exchange-side indoor liquid-refrigerant pipe that connects a liquid side of the indoor heat exchanger to the indoor expansion valve; and
a connection-side indoor liquid-refrigerant pipe that connects the indoor expansion valve to the liquid-refrigerant connection pipe, wherein
the indoor expansion valve is connected to the connection-side indoor liquid-refrigerant pipe by brazing, and
a coating material is disposed over brazing portions of the indoor expansion valve and the connection-side indoor liquid-refrigerant pipe.
24. The indoor unit according to claim 23 , further comprising:
a gas-side shutoff valve that is connected to a gas side of the indoor heat exchanger;
a heat-exchange-side indoor gas-refrigerant pipe that connects the gas side of the indoor heat exchanger to the gas-side shutoff valve; and
a connection-side indoor gas-refrigerant pipe that connects the gas-side shutoff valve to the gas-refrigerant connection pipe, wherein
the gas-side shutoff valve is connected to the connection-side indoor gas-refrigerant pipe by brazing, and
a coating material is disposed over brazing portions of the gas-side shutoff valve and the connection-side indoor gas-refrigerant pipe.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017002780A JP7215819B2 (en) | 2017-01-11 | 2017-01-11 | Air conditioner and indoor unit |
JP2017-002780 | 2017-01-11 | ||
PCT/JP2017/046182 WO2018131432A1 (en) | 2017-01-11 | 2017-12-22 | Air conditioning device and indoor unit |
Publications (1)
Publication Number | Publication Date |
---|---|
US20210131706A1 true US20210131706A1 (en) | 2021-05-06 |
Family
ID=62840059
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/477,239 Abandoned US20210131706A1 (en) | 2017-01-11 | 2017-12-22 | Air conditioner and indoor unit |
Country Status (6)
Country | Link |
---|---|
US (1) | US20210131706A1 (en) |
EP (1) | EP3569944B1 (en) |
JP (1) | JP7215819B2 (en) |
CN (1) | CN110168288A (en) |
ES (1) | ES2928874T3 (en) |
WO (1) | WO2018131432A1 (en) |
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US20220065505A1 (en) * | 2020-08-28 | 2022-03-03 | Lg Electronics Inc. | Multi-air conditioner for heating and cooling and method for controlling multi-air conditioner for heating and cooling |
US11274863B2 (en) * | 2017-09-29 | 2022-03-15 | Daikin Industries, Ltd. | Air conditioning system |
US11448455B2 (en) * | 2019-03-25 | 2022-09-20 | Samsung Electronics Co., Ltd. | Refrigerator |
US20230304712A1 (en) * | 2021-07-23 | 2023-09-28 | Goodman Manufacturing Company, L.P. | Hvac equipment with refrigerant gas sensor |
US11821458B2 (en) * | 2017-07-21 | 2023-11-21 | Daikin Industries, Ltd. | Refrigerant-channel branching component, and refrigeration apparatus including refrigerant-channel branching component |
US11927377B2 (en) | 2014-09-26 | 2024-03-12 | Waterfurnace International, Inc. | Air conditioning system with vapor injection compressor |
US11953239B2 (en) | 2018-08-29 | 2024-04-09 | Waterfurnace International, Inc. | Integrated demand water heating using a capacity modulated heat pump with desuperheater |
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CN109084421B (en) | 2018-08-03 | 2020-08-18 | 广东美的暖通设备有限公司 | Control method and control device of air conditioner and air conditioner |
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- 2017-12-22 EP EP17891222.6A patent/EP3569944B1/en active Active
- 2017-12-22 CN CN201780083000.4A patent/CN110168288A/en active Pending
- 2017-12-22 WO PCT/JP2017/046182 patent/WO2018131432A1/en unknown
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US11927377B2 (en) | 2014-09-26 | 2024-03-12 | Waterfurnace International, Inc. | Air conditioning system with vapor injection compressor |
US11821458B2 (en) * | 2017-07-21 | 2023-11-21 | Daikin Industries, Ltd. | Refrigerant-channel branching component, and refrigeration apparatus including refrigerant-channel branching component |
US11274863B2 (en) * | 2017-09-29 | 2022-03-15 | Daikin Industries, Ltd. | Air conditioning system |
US11953239B2 (en) | 2018-08-29 | 2024-04-09 | Waterfurnace International, Inc. | Integrated demand water heating using a capacity modulated heat pump with desuperheater |
US11448455B2 (en) * | 2019-03-25 | 2022-09-20 | Samsung Electronics Co., Ltd. | Refrigerator |
US20220065505A1 (en) * | 2020-08-28 | 2022-03-03 | Lg Electronics Inc. | Multi-air conditioner for heating and cooling and method for controlling multi-air conditioner for heating and cooling |
US11892209B2 (en) * | 2020-08-28 | 2024-02-06 | Lg Electronics Inc. | Multi-air conditioner for heating and cooling including a shut-off valve between indoor and outdoor units and control method thereof |
US20230304712A1 (en) * | 2021-07-23 | 2023-09-28 | Goodman Manufacturing Company, L.P. | Hvac equipment with refrigerant gas sensor |
Also Published As
Publication number | Publication date |
---|---|
WO2018131432A1 (en) | 2018-07-19 |
EP3569944A1 (en) | 2019-11-20 |
JP7215819B2 (en) | 2023-01-31 |
EP3569944A4 (en) | 2020-09-09 |
ES2928874T3 (en) | 2022-11-23 |
JP2018112350A (en) | 2018-07-19 |
CN110168288A (en) | 2019-08-23 |
EP3569944B1 (en) | 2022-08-03 |
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