WO2013001976A1 - Air conditioner - Google Patents

Air conditioner Download PDF

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Publication number
WO2013001976A1
WO2013001976A1 PCT/JP2012/064098 JP2012064098W WO2013001976A1 WO 2013001976 A1 WO2013001976 A1 WO 2013001976A1 JP 2012064098 W JP2012064098 W JP 2012064098W WO 2013001976 A1 WO2013001976 A1 WO 2013001976A1
Authority
WO
WIPO (PCT)
Prior art keywords
heat exchange
refrigerant
heat exchanger
exchange path
path
Prior art date
Application number
PCT/JP2012/064098
Other languages
French (fr)
Japanese (ja)
Inventor
道明　伸夫
利行 栗原
康介 森本
Original Assignee
ダイキン工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ダイキン工業株式会社 filed Critical ダイキン工業株式会社
Priority to CN201280032321.9A priority Critical patent/CN103635754A/en
Priority to KR1020147001871A priority patent/KR20140026630A/en
Priority to US14/126,684 priority patent/US20140116078A1/en
Priority to EP12803614.2A priority patent/EP2741021A4/en
Publication of WO2013001976A1 publication Critical patent/WO2013001976A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B29/00—Combined heating and refrigeration systems, e.g. operating alternately or simultaneously
    • F25B29/003—Combined heating and refrigeration systems, e.g. operating alternately or simultaneously of the compression type system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
    • F24F1/14—Heat exchangers specially adapted for separate outdoor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
    • F24F1/26—Refrigerant piping
    • F24F1/30—Refrigerant piping for use inside the separate outdoor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/89—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F25B47/022—Defrosting cycles hot gas defrosting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/0408—Multi-circuit heat exchangers, e.g. integrating different heat exchange sections in the same unit or heat exchangers for more than two fluids
    • F28D1/0426—Multi-circuit heat exchangers, e.g. integrating different heat exchange sections in the same unit or heat exchangers for more than two fluids with units having particular arrangement relative to the large body of fluid, e.g. with interleaved units or with adjacent heat exchange units in common air flow or with units extending at an angle to each other or with units arranged around a central element
    • F28D1/0443—Combination of units extending one beside or one above the other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/047—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag
    • F28D1/0477—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag the conduits being bent in a serpentine or zig-zag
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/026—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits
    • F28F9/027—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits in the form of distribution pipes
    • F28F9/0275—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits in the form of distribution pipes with multiple branch pipes
    • 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
    • F24F11/41—Defrosting; Preventing freezing
    • F24F11/42—Defrosting; Preventing freezing of outdoor units
    • 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
    • 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
    • F25B2313/025—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units
    • F25B2313/0251—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units being defrosted alternately
    • 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
    • F25B2313/025—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units
    • F25B2313/0253—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units in parallel arrangements
    • 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

Definitions

  • the present invention relates to an air conditioner, and more particularly to an air conditioner capable of performing a heating operation.
  • a compressor, an indoor heat exchanger, and an outdoor heat exchanger are connected in order, and heating is performed by circulating a refrigerant in the order of the compressor, the indoor heat exchanger, the outdoor heat exchanger, and the compressor.
  • the refrigerant is switched in the order of the compressor, the outdoor heat exchanger, the indoor heat exchanger, and the compressor by a four-way switching valve or the like.
  • the reverse cycle defrost operation is performed to defrost the outdoor heat exchanger. For this reason, in this air conditioner, the heating operation stops during the reverse cycle defrost operation, and the comfort in the room is impaired.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2000-274780 discloses a defrost method for defrosting the outdoor heat exchanger while continuing the heating operation. And an air conditioner as shown in Patent Document 2 (Japanese Patent Laid-Open No. 2001-059994) has been proposed.
  • an electromagnetic valve is provided at each of the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger.
  • the flow of the refrigerant in the heat exchange path is stopped by closing the electromagnetic valve of the heat exchange path arbitrarily selected. I try to drive.
  • the heating operation can be continued by defrosting an arbitrary heat exchange path with the heat of the outdoor air and evaporating the refrigerant in another heat exchange path.
  • a bypass path for sending a part of the refrigerant discharged from the compressor to the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger without sending it to the indoor heat exchanger is provided. I am trying to provide it.
  • the outdoor heat exchanger is not sent to the indoor heat exchanger through the bypass passage, without sending a part of the refrigerant discharged from the compressor.
  • the operation is sent to any heat exchange path. With this operation, in this air conditioner, heating is performed by evaporating the refrigerant in another heat exchange path while defrosting the arbitrary heat exchange path by the heat of the refrigerant sent to the arbitrary heat exchange path through the bypass. The operation can be continued.
  • An object of the present invention is to enable an outdoor heat exchanger to be defrosted in an air-conditioning apparatus capable of performing a heating operation with almost no decrease in heating capacity.
  • An air conditioner includes a compressor that compresses a refrigerant, an indoor heat exchanger that dissipates heat of the refrigerant compressed in the compressor, and heat generated by the indoor heat exchanger that radiates heat from the outdoor air.
  • An outdoor heat exchanger that evaporates by exchange is sequentially connected.
  • This air conditioner can perform a heating operation in which refrigerant is circulated in the order of a compressor, an indoor heat exchanger, an outdoor heat exchanger, and a compressor.
  • the outdoor heat exchanger has a plurality of heat exchange paths connected to each other in parallel.
  • the liquid side ends of the plurality of heat exchange paths are connected in parallel by a refrigerant shunt for branching the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to the liquid side ends of the plurality of heat exchange paths.
  • the air conditioner is arbitrarily selected from a plurality of heat exchange paths without allowing the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to flow into the refrigerant distributor, on the premise of the above configuration.
  • a defrosting flow path mechanism is used to perform a heating defrost operation for evaporating the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger while defrosting an arbitrary heat exchange path. It has become.
  • this heating defrost operation first, the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger is not allowed to flow into the refrigerant diverter by the defrost flow path mechanism, but from the gas side end of any heat exchange path. It passes through an arbitrary heat exchange path toward the side edge. Next, the refrigerant that has passed through any heat exchange path passes through the other heat exchange path from the liquid side end to the gas side end of the other heat exchange path other than the arbitrary heat exchange path through the refrigerant flow divider.
  • the entire outdoor heat exchanger can be defrosted by sequentially performing the heating defrost operation using the defrost flow path mechanism on the plurality of heat exchange paths.
  • this heating defrost operation the entire flow rate of the refrigerant compressed in the compressor is sent to the indoor heat exchanger and used for heating, and then removed by the heat of the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger.
  • Frost can be done. Thereby, defrosting of the outdoor heat exchanger can be performed while obtaining a high defrosting capacity without substantially reducing the heating capacity and also in a weather condition where the outside air temperature is 0 ° C. or less.
  • An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the outdoor heat exchanger before the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger flows into the refrigerant distributor. It further has a subcooling path through. Then, the defrosting flow path mechanism allows the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to pass through the supercooling path, and then the gas in the heat exchange path arbitrarily selected from the plurality of heat exchange paths. It is provided so that it can be sent to the side end.
  • An air conditioner according to a third aspect is the air conditioner according to the first aspect, wherein the outdoor heat exchanger before the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger flows into the refrigerant distributor. It further has a subcooling path through. Then, the defrosting flow path mechanism is configured such that the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger passes through the subcooling path, and the gas in the heat exchange path arbitrarily selected from the plurality of heat exchange paths. It is provided so that it can be sent to the side end.
  • the heat exchange path can be defrosted without passing the refrigerant through the supercooling path during the heating defrost operation, so the heat of the refrigerant is used only for the defrosting of the heat exchange path. Can do.
  • FIG. 1 It is a schematic structure figure of the air harmony device concerning a 1st embodiment of the present invention. It is a top view (illustrated by removing the top plate) of the outdoor unit. It is the figure which showed typically the outdoor heat exchanger of 1st Embodiment, and the structure of the vicinity. It is a control block diagram of an air conditioning apparatus. It is a figure which shows the flow of the refrigerant
  • FIG. 3 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation of the first embodiment.
  • FIG. 6 is a pressure-enthalpy diagram illustrating a conventional refrigeration cycle during defrost operation (Patent Document 2). It is a flowchart of the heating defrost driving
  • FIG. 6 is a pressure-enthalpy diagram illustrating a refrigeration cycle during a heating defrost operation according to a second embodiment. It is a schematic block diagram of the air conditioning apparatus concerning the modification 2 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant
  • FIG. 1 is a schematic configuration diagram of an air-conditioning apparatus 1 according to the first embodiment of the present invention.
  • the air conditioner 1 can perform a heating operation, and a split type is adopted here.
  • the air conditioner 1 mainly includes an outdoor unit 2, an indoor unit 4, and a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6 that connect the outdoor unit 2 and the indoor unit 4.
  • the outdoor unit 2 and the indoor unit 4 constitute a refrigerant circuit 10 for performing a vapor compression refrigeration cycle by being connected via a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6.
  • the indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 10.
  • the indoor unit 4 mainly has an indoor heat exchanger 41.
  • the indoor heat exchanger 41 is a heat exchanger that functions as a refrigerant evaporator during cooling operation to cool indoor air, and functions as a refrigerant radiator during heating operation to heat indoor air.
  • a cross fin type fin-and-tube heat exchanger constituted by heat transfer tubes and a large number of fins is employed as the indoor heat exchanger 41.
  • the indoor heat exchanger 41 has a liquid side connected to the liquid refrigerant communication tube 5 and a gas side connected to the gas refrigerant communication tube 6.
  • the indoor unit 4 has an indoor control unit 49 that controls the operation of each unit constituting the indoor unit 4.
  • the indoor control unit 41 includes a microcomputer and a memory for controlling the indoor unit 4, and exchanges control signals and the like with the outdoor control unit 29 (described later) of the outdoor unit 2. Be able to.
  • the outdoor unit 2 is installed outside and constitutes a part of the refrigerant circuit 10.
  • the outdoor unit 2 mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an expansion valve 24, an outdoor fan 25, and a defrost flow path mechanism 26.
  • the outdoor unit 2 has a structure in which the inside of a substantially rectangular parallelepiped box-shaped unit casing 51 is divided into a blower chamber S ⁇ b> 1 and a machine chamber S ⁇ b> 2 by a partition plate 58 extending vertically (so-called trunk Mold structure) is adopted.
  • FIG. 2 is a plan view of the outdoor unit 2 (illustrated with the top plate removed).
  • the unit casing 51 mainly includes a bottom plate 52, a top plate, a left front plate 54, a right front plate 56, a right side plate 57, and a partition plate 58.
  • the bottom plate 52 is a horizontally long and substantially rectangular plate-like member that constitutes the bottom surface portion of the unit casing 51.
  • the bottom plate 52 functions as a drain pan for receiving drain water flowing down from the outdoor heat exchanger 23.
  • the top plate is a horizontally long and substantially rectangular plate-like member that constitutes the top surface portion of the outdoor unit 2.
  • the left front plate 54 is a plate-like member mainly constituting the left front surface portion and the left side surface portion of the unit casing 51.
  • the left front plate 54 is formed with a suction port 55a for air sucked into the unit casing 51 by the outdoor fan 25. Further, the left front plate 54 is provided with an outlet 54a for blowing out air taken in from the back side and the left side of the unit casing 51 by the outdoor fan 25 to the outside.
  • the right front plate 56 is a plate-like member that mainly constitutes the front portion of the right front surface and the right side surface of the unit casing 51.
  • the right side plate 57 is a plate-like member that mainly constitutes the rear portion and the right back portion of the right side surface of the unit casing 51.
  • the partition plate 58 is a vertically extending plate-like member disposed on the bottom plate 52, and is disposed so as to partition the internal space of the unit casing 51 into two left and right spaces (that is, the fan chamber S1 and the machine chamber S2). Yes.
  • the compressor 21 is a compressor for sucking and compressing a low-pressure gas refrigerant in the refrigeration cycle to form a high-pressure gas refrigerant in the refrigeration cycle.
  • a volumetric compression element such as a rotary type or a scroll type accommodated in a casing (not shown) is used by a compressor motor 21a also accommodated in the casing.
  • a driven hermetic compressor is employed.
  • the suction side and the discharge side of the compressor 21 are connected to the four-way switching valve 22.
  • the compressor 21 is disposed in the machine room S2.
  • the four-way switching valve 22 is a valve for switching the direction of the refrigerant flow when switching between the cooling operation and the heating operation.
  • the four-way switching valve 22 can connect the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 and can connect the gas refrigerant communication pipe 6 and the suction side of the compressor 21 during cooling operation. (Refer to the solid line of the four-way switching valve 22 in FIG. 1).
  • the four-way switching valve 22 connects the discharge side of the compressor 21 and the gas refrigerant communication pipe 6 and connects the gas side of the outdoor heat exchanger 23 and the suction side of the compressor 21 during heating operation. (Refer to the broken line of the four-way switching valve 22 in FIG. 1).
  • the four-way switching valve 22 is connected to the gas refrigerant communication pipe 6, the suction side and discharge side of the compressor 21, and the gas side of the outdoor heat exchanger 23.
  • the four-way switching valve 22 is disposed in the machine room S2.
  • the outdoor heat exchanger 23 is a heat exchanger that functions as a refrigerant radiator during cooling operation and functions as a refrigerant evaporator during heating operation.
  • a cross fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins is employed as the outdoor heat exchanger 23 .
  • the outdoor heat exchanger 23 has a liquid side connected to the expansion valve 24 via a liquid refrigerant pipe 27, and a gas side connected to the four-way switching valve 22 via a gas refrigerant pipe 28. More specifically, the outdoor heat exchanger 23 includes a large number of fins 61 and a large number of heat transfer tubes 62 attached in a state where these fins 61 are penetrated in the plate thickness direction (FIG. 2). See).
  • the heat transfer tubes 61 are divided into a plurality of (here, three) systems in the vertical direction, and these are separated from each other by a first heat exchange path 31,
  • the second heat exchange path 32 and the third heat exchange path 33 are provided.
  • FIG. 3 is the figure which showed typically the structure of the outdoor heat exchanger 23 and its vicinity.
  • the liquid side ends of the first to third heat exchange paths 31 to 33 are connected to the refrigerant distributor 64 via the first to third capillary tubes 63a to 63c, respectively.
  • the refrigerant flow divider 64 is a pipe member that joins the first to third capillary tubes 63 a to 63 c connected to the liquid side ends of the first to third heat exchange paths 31 to 33, and is connected to the liquid refrigerant pipe 27. ing.
  • the gas side ends of the first to third heat exchange paths 31 to 33 are connected to the header 66 via first to third header communication pipes 65a to 65c, respectively.
  • the header 66 is a pipe member that joins the first to third header connecting pipes 65a to 65c connected to the gas side ends of the first to third heat exchange paths 31 to 33, and is connected to the gas refrigerant pipe 28. Yes.
  • the plurality of (here, three) heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 are connected in parallel to each other via the refrigerant flow divider 64 and the header 66.
  • all the heat exchange paths 31 to 33 function as a refrigerant radiator, and during the heating operation, all the heat exchange paths 31 to 33 function as a refrigerant evaporator.
  • the outdoor heat exchanger 23 (that is, the heat exchange paths 31 to 33) has an L shape extending from the left side surface of the unit casing 51 to the back surface.
  • the pipe members 63a to 63c, 64, 65a to 65c, 66 for connecting the heat exchange paths 31 to 33 are not shown in FIG. 2, but the right end space of the outdoor heat exchanger 23, that is, the machine room. Arranged in S2.
  • the expansion valve 24 depressurizes the high-pressure liquid refrigerant radiated in the outdoor heat exchanger 23 during the cooling operation before sending it to the indoor heat exchanger 41, and the high-pressure liquid refrigerant radiated in the indoor heat exchanger 41 during the heating operation. This is an electric expansion valve that can be decompressed before being sent to the heat exchanger 23.
  • the expansion valve 24 is provided in the liquid refrigerant pipe 27, one end of which is connected to the liquid refrigerant communication pipe 5, and the other end is connected to the outdoor heat exchanger 23. Although not shown in FIG. 2, the expansion valve 24 is disposed in the machine room S2.
  • the outdoor fan 25 is a blower for sucking outdoor air into the outdoor unit 2, supplying the outdoor air to the outdoor heat exchanger 23, and then discharging the air outside the unit.
  • a propeller fan driven by an outdoor fan motor 25a is employed as the outdoor fan 25 .
  • the outdoor fan 25 is disposed on the front side of the outdoor heat exchanger 23 in the blower chamber S1.
  • the outdoor fan 23 is driven, air is taken into the interior through the suction ports 55a and 55b on the back surface and the left side surface of the unit casing 51, and after passing through the outdoor heat exchanger 23, the air outlet 54a on the front surface of the unit casing 51.
  • the air is blown out from the unit casing 51 to the outside.
  • the outdoor heat exchanger 23 is a heat exchanger that radiates the refrigerant using outdoor air as a cooling source or evaporates the refrigerant using outdoor air as a heating source.
  • the defrosting flow path mechanism 26 is arbitrarily selected from the plurality of heat exchange paths 31 to 33 without causing the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 to flow into the refrigerant flow divider 64. It is a mechanism for sending to the gas side end of the heat exchange path.
  • the defrost flow path mechanism 26 is provided to perform a heating defrost operation which will be described later. In this heating defrost operation, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 while defrosting any heat exchange path among the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23. It is the operation which evaporates.
  • the defrost flow path mechanism 26 mainly includes a heat exchange path supply pipe 71, a plurality (here, three) of heat exchange path branch pipes 72a to 72c, and a plurality (here, three) of branch pipe side heat. There are exchange path selection valves 73a to 73c, a plurality (three in this case) of header side heat exchange path selection valves 74a to 74c, and a branch pipe side selection valve 75.
  • the defrost channel mechanism 26 (that is, the refrigerant pipes and valves 71, 72a to 72c, 73a to 73c, 74a to 74c, 75) is disposed in the machine room S2, although not shown in FIG.
  • the heat exchange path supply pipe 71 is a refrigerant pipe for branching from the liquid refrigerant pipe 27 before the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 flows into the refrigerant flow divider 64.
  • One end of the heat exchange path supply pipe 71 is connected to a portion of the liquid refrigerant pipe 27 between the expansion valve 24 and the refrigerant distributor 64, and the other end is connected to the heat exchange path branch pipes 72a to 72c.
  • the first to third heat exchange path branch pipes 72a to 72c are refrigerant pipes for supplying the refrigerant flowing through the heat exchange path supply pipe 71 to the gas side ends of the first to third heat exchange paths 31 to 33.
  • Each of the first to third heat exchange path branch pipes 72a to 72c has one end connected to the heat exchange path supply pipe 71 and the other end connected to the first to third header communication pipes 65a to 65c. Yes.
  • the first to third branch pipe side heat exchange path selection valves 73a to 73c, together with the first to third header side heat exchange path selection valves 74a to 74c, allow the refrigerant flowing through the heat exchange path supply pipe 71 to pass through the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to.
  • the first to third branch pipe side heat exchange path selection valves 73a to 73c are provided in the first to third heat exchange path branch pipes 72a to 72c, respectively.
  • the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed. Further, during the heating defrost operation, the branch pipe side heat exchange path selection valve corresponding to the heat exchange path for defrosting among the first to third branch pipe side heat exchange path selection valves 73a to 73c is opened. The branch pipe side heat exchange path selection valve corresponding to the heat exchange path is closed.
  • the first to third header side heat exchange path selection valves 74a to 74c, together with the first to third branch pipe side heat exchange path selection valves 73a to 73c, transfer the refrigerant flowing through the heat exchange path supply pipe 71 to the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to.
  • the first to third header side heat exchange path selection valves 74a to 74c are connected to the other ends of the first to third heat exchange path branch pipes 72a to 72c among the first to third header communication pipes 65a to 65c, respectively. It is provided in a portion between the position and the header 66.
  • all of the first to third header side heat exchange path selection valves 74a to 74c are opened.
  • the header side heat exchange path selection valve corresponding to the heat exchange path for defrosting is closed among the first to third header side heat exchange path selection valves 74a to 74c, and the other heat exchanges are performed.
  • the header side heat exchange path selection valve corresponding to the path can be opened.
  • the branch pipe side selection valve 75 is an electromagnetic valve for selecting whether the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is branched from the liquid refrigerant pipe 27 before flowing into the flow divider 64. .
  • the branch pipe side selection valve 75 is provided in a portion between the position where the heat exchange path supply pipe 71 is branched in the liquid refrigerant pipe 27 and the refrigerant flow divider 64. And the shunt pipe side selection valve 75 is opened at the time of air_conditionaing
  • the outdoor unit 2 is provided with an outdoor heat exchange temperature sensor 67 that detects a saturation temperature Tsat of the refrigerant flowing through the outdoor heat exchanger 23.
  • the outdoor heat exchange temperature sensor 67 is provided in the vicinity of the liquid side end of the first heat exchange path 31 of the outdoor heat exchanger 23.
  • the outdoor unit 2 also has an outdoor control unit 29 that controls the operation of each part constituting the outdoor unit 2.
  • the outdoor control unit 29 includes a microcomputer and a memory for controlling the outdoor unit 2, and can exchange control signals and the like with the indoor control unit 49 of the indoor unit 4. It is like that.
  • FIG. 4 is a control block diagram of the air conditioner 1. (Operation) Next, operation
  • the control unit 8 performs control of various devices and various processes necessary for performing the following operations.
  • the operation of the air conditioner 1 includes a cooling operation that cools the room, a heating operation that only heats the room, and a heating defrost operation that heats the room while defrosting the outdoor heat exchanger 23. .
  • FIG. 1 is a control block diagram of the air conditioner 1.
  • FIG. 5 is a diagram illustrating the flow of the refrigerant in the air conditioner 1 during the heating operation.
  • FIG. 6 is a flowchart of the heating defrost operation.
  • FIG. 7 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating and defrosting operation (when defrosting the first heat exchange path 31).
  • FIG. 8 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation.
  • the cooling operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the outdoor heat exchanger 23, the indoor heat exchanger 41, and the compressor 21.
  • the outdoor heat exchanger 23 functions as a refrigerant radiator
  • the indoor heat exchanger 41 functions as a refrigerant evaporator, thereby cooling indoor air.
  • the outdoor heat exchanger 23 functions as a refrigerant radiator
  • the indoor heat exchanger 41 functions as a refrigerant evaporator (that is, indicated by the solid line of the four-way switching valve 22 in FIG. 1).
  • the four-way selector valve 22 is switched so that Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26.
  • the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle.
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 through the four-way switching valve 22.
  • the high-pressure refrigerant discharged from the compressor 21 passes through the four-way switching valve 22, the gas refrigerant pipe 28, the header 66, the header communication pipes 65a to 65c, and the header side heat exchange path selection valves 74a to 74c. It is sent to the gas side ends of the heat exchange paths 31 to 33 of the heat exchanger 23.
  • the high-pressure refrigerant sent to the gas side ends of the heat exchange paths 31 to 33 performs heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33 to radiate heat.
  • the high-pressure refrigerant radiated in the heat exchange paths 31 to 33 is selected from the liquid side ends of the heat exchange paths 31 to 33 from the capillary tubes 63a to 63c, the refrigerant flow divider 64, the liquid refrigerant pipe 27, and the branch pipe side selection. It is sent to the expansion valve 24 through the valve 75.
  • the refrigerant sent to the expansion valve 24 is depressurized to a low pressure in the refrigeration cycle.
  • the low-pressure refrigerant decompressed by the expansion valve 24 is sent to the indoor heat exchanger 41 through the liquid refrigerant communication pipe 5.
  • the low-pressure refrigerant sent to the indoor heat exchanger 41 evaporates by exchanging heat with indoor air in the indoor heat exchanger 41.
  • the low-pressure refrigerant evaporated in the indoor heat exchanger 41 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6 and the four-way switching valve 22.
  • the heating operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • the outdoor heat exchanger 23 functions as a refrigerant evaporator, thereby heating indoor air.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • the outdoor heat exchanger 23 functions as a refrigerant evaporator (that is, the four-way switching valve 22 in FIGS. 1 and 5).
  • the four-way switching valve 22 is switched so as to be in a state indicated by a broken line.
  • first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26.
  • the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle.
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22.
  • the high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41.
  • the high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and depressurized to a low pressure in the refrigeration cycle.
  • the low-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 23.
  • the low-pressure refrigerant decompressed by the expansion valve 24 passes through the liquid refrigerant pipe 27, the branch pipe side selection valve 75, the refrigerant flow divider 64, and the capillary tubes 63a to 63c, and the heat exchange path 31 of the outdoor heat exchanger 23.
  • the low-pressure refrigerant sent to the liquid side ends of the heat exchange paths 31 to 33 evaporates through heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33.
  • the low-pressure refrigerant evaporated in the heat exchange paths 31 to 33 flows from the gas side ends of the heat exchange paths 31 to 33 to the header communication pipes 65a to 65c, the header side heat exchange path selection valves 74a to 74c, the header 66, and the gas.
  • the refrigerant is again sucked into the compressor 21 through the refrigerant pipe 28 and the four-way switching valve 22.
  • the heating defrost operation is performed by circulating the refrigerant in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21.
  • the outdoor heat exchanger 23 is defrosted.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • any one of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 is a refrigerant radiator.
  • the remaining heat exchange paths 31 to 33 function as a refrigerant evaporator.
  • the indoor air is heated while the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 are sequentially defrosted.
  • the switching state of the four-way switching valve 22 in the heating defrost operation is the same as in the heating operation. That is, the four-way switching valve 22 is in a state in which the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 23 functions as a refrigerant evaporator (that is, the four-way valves in FIGS. 1 and 7). The state shown by the broken line of the switching valve 22). Further, since the defrosting of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 is sequentially performed, the selection valves 73a to 73c, 74a to 74c, and 75 are different from those during the cooling operation and the heating operation. Switch to open / closed state.
  • the refrigerant flows through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26.
  • the operation during the heating defrost operation will be described in detail including the procedure from the start to the end of the heating defrost operation.
  • step S1 it is determined whether the amount of frost formation in the outdoor heat exchanger 23 has increased due to the heating operation, and defrosting has become necessary. Although it is conceivable to determine whether or not this defrosting is necessary based on the duration of the heating operation or the temperature of the outdoor heat exchanger 23, here, the saturation temperature Tsat detected by the outdoor heat exchanger temperature sensor 67. Judgment based on. Specifically, when the saturation temperature Tsat is equal to or lower than the predetermined temperature Tm, it is determined that defrosting of the outdoor heat exchanger 23 is necessary. And when it determines with the defrosting of the outdoor heat exchanger 23 being required in step S1, it transfers to the process of step S2.
  • the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 are sequentially defrosted.
  • the defrosting of the first to third heat exchange paths 31 to 33 may basically be arbitrarily selected, but the flow of drain water generated by the defrosting to the bottom plate 52 of the unit casing 51 is considered. Then, it is preferable to carry out from the upper part of the outdoor heat exchanger 23 toward the lower part. For this reason, here, defrosting shall be performed in the order of the first heat exchange path 31, the second heat exchange path 32, and the third heat exchange path 33.
  • the defrosting (step S2) of the first heat exchange path 31 is performed by switching the open / close states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26. Specifically, the first branch pipe side heat exchange path selection valve 73a is opened, the second and third branch pipe side heat exchange path selection valves 73b and 73c are closed, and the first header side heat exchange path selection valve 74a is closed. Is closed, the second and third header side heat exchange path selection valves 74b and 74c are opened, and the flow dividing pipe side selection valve 75 is switched to a closed state.
  • the first branch pipe side heat exchange path selection valve 73a is opened and the first header side heat exchange path is opened.
  • a switching operation for closing the selection valve 74a and closing the branch pipe side selection valve 75 is performed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the first heat exchange path branch pipe 72a of the defrost flow path mechanism 26.
  • the low-pressure refrigerant in the refrigeration cycle (see point A in FIGS. 7 and 8) is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle (See point B in FIGS. 7 and 8).
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22.
  • the high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41 (see point C in FIGS. 7 and 8). Up to this point, it is the same as in the heating operation.
  • the high-pressure refrigerant that has radiated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and is reduced to a pressure between the high pressure and the low pressure (hereinafter referred to as intermediate pressure) in the refrigeration cycle. (See point D in FIGS. 7 and 8).
  • the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent to the outdoor heat exchanger 23.
  • the intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the first heat exchange path branch pipe 72a, the first branch pipe side heat exchange path selection valve 73a, and the first header communication pipe 65a. It is sent to the gas side end of the first heat exchange path 31 of the heat exchanger 23.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the first heat exchange path 31 without flowing into the refrigerant flow divider 64.
  • the intermediate-pressure refrigerant sent to the gas side end of the first heat exchange path 31 passes through the first heat exchange path 31 from the gas side end of the first heat exchange path 31 toward the liquid side end, Frost adhering to the first heat exchange path 31 of the outdoor heat exchanger 23 is melted (see point E in FIGS. 7 and 8). Thereby, defrosting of the 1st heat exchange path 31 of the outdoor heat exchanger 23 is performed.
  • the intermediate-pressure refrigerant that has passed through the first heat exchange path 31 is sent from the liquid side end of the first heat exchange path 31 to the refrigerant flow divider 64 through the first capillary tube 63a.
  • the first capillary tube 63a flows an intermediate-pressure refrigerant having a larger flow rate than that during the cooling operation or the heating operation. Therefore, the first capillary tube 63a has a pressure loss as compared with the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure in the refrigeration cycle (that is, the pressure at point E in FIGS. 7 and 8) and the low pressure (see point F in FIGS. 7 and 8).
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the second and third capillary tubes 63b, because the flow dividing pipe side selection valve 75 is closed.
  • the low-pressure refrigerant evaporated in the second and third heat exchange paths 32 and 33 is supplied from the gas side ends of the second and third heat exchange paths 32 and 33 to the second and third header communication pipes 65b, 65c,
  • the air is again sucked into the compressor 21 through the second and third header side heat exchange path selection valves 74b and 74c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22.
  • defrosting of the first heat exchange path 31 is started while continuing the indoor heating.
  • defrosting of the 1st heat exchange path 31 is performed until defrosting of the 1st heat exchange path 31 is completed (step S3).
  • the defrosting time t1 of the first heat exchange path 31 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the first heat exchange path 31 can be regarded as completed) has elapsed. .
  • the defrosting (step S4) of the second heat exchange path 32 is performed by switching the open / closed states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26 in the same manner as the first heat exchange path 31. Done. Specifically, the second branch pipe side heat exchange path selection valve 73b is opened, the first and third branch pipe side heat exchange path selection valves 73a and 73c are closed, and the second header side heat exchange path selection valve 74b. Is closed, the first and third header side heat exchange path selection valves 74a and 74c are opened, and the branch pipe side selection valve 75 is switched to a closed state.
  • the second branch pipe side heat exchange path selection valve 73b is opened, A switching operation is performed in which the first branch pipe side heat exchange path selection valve 73a is closed, the first header side heat exchange path selection valve 74a is opened, and the second header side heat exchange path selection valve 74b is closed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the second heat exchange path branch pipe 72b of the defrost flow path mechanism 26.
  • the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same manner as in the defrosting of the first heat exchange path 31, and in the indoor heat exchanger 41 Heat is exchanged with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends it to the outdoor heat exchanger 23.
  • the intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the second heat exchange path branch pipe 72b, the second branch pipe side heat exchange path selection valve 73b, and the second header communication pipe 65b. It is sent to the gas side end of the second heat exchange path 32 of the heat exchanger 23.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the second heat exchange path 32 without flowing into the refrigerant flow divider 64.
  • the intermediate-pressure refrigerant sent to the gas side end of the second heat exchange path 32 passes through the second heat exchange path 32 from the gas side end of the second heat exchange path 32 toward the liquid side end,
  • the frost adhering to the second heat exchange path 32 of the outdoor heat exchanger 23 is melted.
  • the 2nd heat exchange path 32 of the outdoor heat exchanger 23 is defrosted.
  • the intermediate-pressure refrigerant that has passed through the second heat exchange path 32 is sent from the liquid side end of the second heat exchange path 32 to the refrigerant flow divider 64 through the second capillary tube 63b.
  • the second capillary tube 63b has a flow rate of intermediate pressure refrigerant that is larger than that during cooling operation or heating operation.
  • the second capillary tube 63b has a pressure loss as compared with the case where the refrigerant flows during cooling operation or heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle.
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and third capillary tubes 63a, since the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the first and third heat exchange paths 31, 33. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and third capillary tubes 63a and 63c.
  • the low-pressure refrigerant sent to the liquid side ends of the first and third heat exchange paths 31 and 33 is first from the liquid side ends of the first and third heat exchange paths 31 and 33 toward the gas side end. And passes through the third heat exchange paths 31 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. Then, the low-pressure refrigerant evaporated in the first and third heat exchange paths 31 and 33 flows from the gas side ends of the first and third heat exchange paths 31 and 33 to the first and third header communication pipes 65a and 65c, The air is again sucked into the compressor 21 through the first and third header side heat exchange path selection valves 74 a and 74 c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22.
  • defrosting of the second heat exchange path 32 is started while continuing the indoor heating. And the defrosting of the 2nd heat exchange path 32 is performed until the defrosting of the 2nd heat exchange path 32 is completed (step S5).
  • the defrosting time t2 of the second heat exchange path 32 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the second heat exchange path 32 can be considered completed) has elapsed. . Since the second heat exchange path 32 and the other heat exchange paths 31 and 33 have different vertical positions, the time during which it can be considered that the defrosting has been completed is also different.
  • the predetermined time for defrosting the second heat exchange path 32 different from the predetermined time for defrosting the other heat exchange paths 31 and 33.
  • the positional relationship of the heat exchange paths 31 to 33 with respect to the outdoor fan 25 is different, and the air volume of the outdoor air passing through the heat exchange paths 31 to 33 is biased. Therefore, the heat exchange path with a larger air volume is frosted. The amount tends to increase. For this reason, it can be considered that the predetermined time for defrosting the heat exchange path with a large air volume is longer than the predetermined time for defrosting the heat exchange path with a small air volume.
  • the defrosting (step S6) of the third heat exchange path 33 is performed by opening and closing the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26, as in the first and second heat exchange paths 31 and 32. This is done by switching the state. Specifically, the third branch pipe side heat exchange path selection valve 73c is opened, the first and second branch pipe side heat exchange path selection valves 73a and 73b are closed, and the third header side heat exchange path selection valve 74c is closed. Is closed, the first and second header side heat exchange path selection valves 74a and 74b are opened, and the branch pipe side selection valve 75 is switched to a closed state.
  • the third branch pipe side heat exchange path selection valve 73c is opened, A switching operation is performed in which the second branch pipe side heat exchange path selection valve 73b is closed, the second header side heat exchange path selection valve 74b is opened, and the third header side heat exchange path selection valve 74c is closed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the third heat exchange path branch pipe 72c of the defrost flow path mechanism 26.
  • the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same way as when the first and second heat exchange paths 31 and 32 are defrosted.
  • the heat exchanger 41 exchanges heat with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends the heat to the outdoor heat exchanger 23.
  • the intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the third heat exchange path branch pipe 72c, the third branch pipe side heat exchange path selection valve 73c, and the third header communication pipe 65c. It is sent to the gas side end of the third heat exchange path 33 of the heat exchanger 23.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the third heat exchange path 33 without flowing into the refrigerant flow divider 64.
  • the intermediate pressure refrigerant sent to the gas side end of the third heat exchange path 33 passes through the third heat exchange path 33 from the gas side end of the third heat exchange path 33 toward the liquid side end,
  • the frost adhering to the third heat exchange path 33 of the outdoor heat exchanger 23 is melted.
  • the 3rd heat exchange path 33 of the outdoor heat exchanger 23 is defrosted.
  • the intermediate-pressure refrigerant that has passed through the third heat exchange path 33 is sent from the liquid side end of the third heat exchange path 33 to the refrigerant flow divider 64 through the third capillary tube 63c.
  • an intermediate pressure refrigerant having a larger flow rate than in the cooling operation or the heating operation flows, so that the pressure loss is smaller than that in the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle.
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and second capillary tubes 63a, because the flow dividing pipe side selection valve 75 is closed. Branched to 63 b and sent to the liquid side ends of the first and second heat exchange paths 31 and 32.
  • the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and second capillary tubes 63a and 63b.
  • the low-pressure refrigerant sent to the liquid side ends of the first and second heat exchange paths 31 and 32 is first from the liquid side ends of the first and second heat exchange paths 31 and 32 toward the gas side ends. Then, it passes through the second heat exchange paths 31 and 32 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25.
  • the low-pressure refrigerant evaporated in the first and second heat exchange paths 31 and 32 flows from the gas side ends of the first and second heat exchange paths 31 and 32 to the first and second header communication pipes 65a and 65b, The air is again sucked into the compressor 21 through the first and second header side heat exchange path selection valves 74a and 74b, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the third heat exchange path 33 is started while continuing the indoor heating. And the defrosting of the 3rd heat exchange path 33 is performed until the defrosting of the 2nd heat exchange path 33 is completed (step S7).
  • the defrosting time t3 of the third heat exchange path 33 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the third heat exchange path 33 can be considered completed) has elapsed.
  • the predetermined time for defrosting the third heat exchange path 33 is also determined in consideration of the positional relationship of the heat exchange paths 31 to 33 with respect to the outdoor fan 25 and the like. It is preferable to make them different from each other.
  • the heating operation is resumed (step S8).
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is defrosted by the defrost flow path mechanism 26 while defrosting any of the heat exchange paths 31 to 33.
  • Evaporative heating operation is performed.
  • the heating defrosting operation is sequentially performed on the plurality of heat exchange paths 31 to 33, so that the entire outdoor heat exchanger 23 is defrosted while the indoor heating is continued.
  • the air conditioner 1 of the present embodiment has the following characteristics.
  • the air conditioner 1 includes the compressor 21 that compresses the refrigerant, the indoor heat exchanger 41 that radiates the refrigerant compressed in the compressor 21, and the refrigerant that has radiated heat in the indoor heat exchanger 41.
  • An outdoor heat exchanger 23 that is evaporated by heat exchange with air is sequentially connected.
  • the air conditioner 1 can perform a heating operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21.
  • the outdoor heat exchanger 23 has a plurality (here, three) of heat exchange paths 31 to 33 connected in parallel to each other.
  • the liquid side ends of the plurality of heat exchange paths 31 to 33 are refrigerant distributors for branching the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 to the liquid side ends of the plurality of heat exchange paths 31 to 33. 64 are connected in parallel.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 does not flow into the refrigerant diverter 64, and the plurality of heat exchange paths 31 to A defrost channel mechanism 26 is further provided for sending to the gas side end of the heat exchange path arbitrarily selected from among 33.
  • the defrosting flow path mechanism 26 performs a heating defrost operation in which the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is evaporated while defrosting an arbitrary heat exchange path. To do.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is not allowed to flow into the refrigerant diverter 64 by the defrost flow path mechanism 26, and the gas in any heat exchange path. It passes through an arbitrary heat exchange path from the side end toward the liquid side end.
  • the refrigerant that has passed through the arbitrary heat exchange path passes through the refrigerant flow divider 64 in the other heat exchange path from the liquid side end of the other heat exchange path other than the arbitrary heat exchange path toward the gas side end. Let it pass.
  • the entire outdoor heat exchanger 23 can be defrosted by sequentially performing the heating defrost operation using the defrost flow path mechanism 26 on the plurality of heat exchange paths 31 to 33. It can be done.
  • an electromagnetic valve is provided at each of the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger, and the electromagnetic valve of the arbitrarily selected heat exchange path is closed. The flow of the refrigerant in the heat exchange path is stopped, and any heat exchange path is defrosted by the heat of the outdoor air.
  • FIG. 9 is a pressure-enthalpy diagram illustrating a conventional refrigeration cycle during defrost operation (Patent Document 2).
  • the entire flow rate of the refrigerant compressed in the compressor 21 is sent to the indoor heat exchanger 41 and used for heating (FIGS. 7 and 8). Then, defrosting is performed by the heat of the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 (see point D in FIGS. 7 and 8). To the point E). Therefore, in the air conditioner 1, unlike the defrost system disclosed in Patent Document 2, the entire flow rate of the refrigerant compressed in the compressor 21 is used for indoor heating, so that the heating capacity is hardly reduced.
  • the total flow rate of the refrigerant compressed in the compressor 21 is used for defrosting an arbitrary heat exchange path of the outdoor heat exchanger 23. Therefore, a high defrosting capability can be obtained.
  • defrosting is completed in a short time, the time which is heating can be lengthened, and integral heating capability can be raised.
  • the heat of the refrigerant is used for defrosting. Therefore, the outdoor heat exchanger 23 can be used even in weather conditions where the outside air temperature is 0 ° C. or less. Defrosting can be performed.
  • the heat exchange path (here, the first heat exchange path 31) constituting the upper part of the outdoor heat exchanger 23 to the heat exchange path (here, the third heat exchange path 33) constituting the lower part. ). For this reason, drain water generated by defrosting can be smoothly drained to the bottom plate 52 of the unit casing 51.
  • the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 are defrosted for a predetermined time set in consideration of the position of the heat exchange path.
  • a predetermined time for defrosting the heat exchange path with a large air volume is considered in consideration of the bias in the air volume of the outdoor air passing through the heat exchange paths 31 to 33 due to the difference in position of the heat exchange paths 31 to 33 with respect to the outdoor fan 25.
  • the predetermined time of defrosting of the heat exchange path where the amount of frost increases because the air volume is large is shortened, and the predetermined time of defrosting of the heat exchange path where the amount of frost decreases because the air volume is small
  • the defrosting of the heat exchange paths 31 to 33 is performed after a predetermined time in which the defrosting times t1 to t3 are set in advance.
  • the present invention is not limited to this.
  • the defrosting of the first heat exchange path 31 that performs defrosting first among the plurality (three in this case) of heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 is performed. This is performed until the saturation temperature Tsat detected by the outdoor heat exchange temperature sensor 67 rises above a predetermined temperature (step S11).
  • this predetermined temperature is set to a temperature at which defrosting of the first heat exchange path 31 can be considered completed.
  • the defrost time t1 at this time is measured, the predetermined time of the defrost of the 2nd and 3rd heat exchange paths 32 and 33 is set from this defrost time t1 (step S12), and the 2nd and 2nd The defrosting of the three heat exchange paths 32 and 33 may be performed only for the set predetermined time (steps S5 and S7).
  • FIG. 10 is a flowchart of the heating defrost operation according to this modification.
  • the heating defrost operation of the present modification is different from the heating defrost operation in which the completion of defrosting of each heat exchange path is determined only by time.
  • the completion of defrosting is detected from the temperature change, and this time is obtained from the time actually required for defrosting.
  • the completion of defrosting of the other heat exchange path is determined based on the predetermined time. For this reason, in the heating defrost operation of this modification, the time required for defrosting of each heat exchange path is set for each heating defrost operation according to the frosting state of the outdoor heat exchanger 23.
  • the predetermined time for defrosting of each heat exchange path is set for each heating defrost operation, compared to the case where the defrosting of each heat exchange path is performed until a predetermined time set in advance. It can be set appropriately.
  • the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a.
  • header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75 but is not limited thereto.
  • a switching valve 77 in which branch pipe side heat exchange path selection valves 73a to 73c are integrated may be used.
  • the switching valve 77 sends the refrigerant flowing through the heat exchange path supply pipe 71 to any of the heat exchange path branch pipes 72a to 72c, or does not send the refrigerant to any of the heat exchange path branch pipes 72a to 72c.
  • This is a switching valve having a function of selecting this.
  • a rotary type switching valve is used as the switching valve 77.
  • the switching valve 77 is connected to the heat exchange path supply pipe 71 and the heat exchange path branch pipes 72a to 72c.
  • a switching valve 77 is connected to the control unit 8 instead of the branch pipe side heat exchange path selection valves 73a to 73c in the control block diagram of FIG. FIG.
  • FIG. 11 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation.
  • FIG. 12 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
  • the switching valve 77 by operating the switching valve 77 so as not to send the refrigerant to any of the heat exchange path branch pipes 72a to 72c, the same heating as in the above embodiment is performed. You can drive. Further, in the operation state of the switching valve 77 similar to that in the heating operation, the same cooling operation as in the above embodiment can be performed. Then, as shown in FIG. 12, the switching valve 77 is operated so as to send the refrigerant flowing through the heat exchange path supply pipe 71 to any one of the heat exchange path branch pipes 72a to 72c. The same heating defrost operation can be performed.
  • the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
  • a switching valve 78 in which a heat exchange path supply pipe 71, branch pipe side heat exchange path selection valves 73a to 73c, and a branch pipe side selection valve 75 are integrated is used. You may do it.
  • the switching valve 78 selects whether the refrigerant flowing through the liquid refrigerant pipe 27 flows to the refrigerant distribution pipe 64 or sent to any one of the heat exchange path branch pipes 72a to 72c, and the heat exchange path branch pipes 72a to 72c.
  • the switching valve has a function of selecting which one of the heat exchange path branch pipes 72a to 72c is sent with the refrigerant.
  • a rotary type switching valve is used as the switching valve 78.
  • the switching valve 78 is connected to the liquid refrigerant pipe 27, the refrigerant distribution pipe 64, and the heat exchange path branch pipes 72a to 72c.
  • a switching valve 78 is connected to the control unit 8 in place of the branch pipe side heat exchange path selection valves 73a to 73c and the branch pipe side selection valve 75 in the control block diagram of FIG. .
  • FIG. 13 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation.
  • FIG. 14 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 (when defrosting the first heat exchange path 31) during the heating defrost operation of the present modification.
  • the heating operation similar to that in the above embodiment is performed. It can be carried out. Further, in the operation state of the switching valve 78 similar to that in the heating operation, the same cooling operation as in the above embodiment can be performed. Then, as shown in FIG. 14, the switching valve 78 is operated so as to send the refrigerant flowing through the liquid refrigerant pipe 27 to any one of the heat exchange path branch pipes 72a to 72c without flowing the refrigerant into the refrigerant distribution pipe 64.
  • the heating defrost operation similar to the embodiment or the first modification can be performed.
  • the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
  • the heat exchange path branch pipes 72a to 72c, the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the header 66 Alternatively, a switching valve 79 may be used.
  • the switching valve 79 selects which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication pipe to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent.
  • the other header communication pipes are switching valves having a function of connecting to the gas refrigerant pipe 28 or selecting not to send the refrigerant to any of the header communication pipes 65a to 65c.
  • FIG. 15 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation.
  • FIG. 16 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
  • the heating operation similar to the above embodiment is performed. It can be carried out.
  • the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 79 similar to that in the heating operation. Then, as shown in FIG. 16, it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent.
  • the heating defrost operation similar to that of the above-described embodiment or modification 1 can be performed. And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, and the structure of the modifications 2, 3, the number of parts which comprise the flow-path mechanism 26 for defrost can be reduced.
  • the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a.
  • the header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75 but is not limited thereto.
  • a switching valve 80 in which 74a to 74c, the branch pipe side selection valve 75, and the header 66 are integrated may be used.
  • the switching valve 80 selects whether the refrigerant flowing through the liquid refrigerant pipe 27 flows to the refrigerant distribution pipe 64 or the header communication pipes 65a to 65c, and the refrigerant flowing through the liquid refrigerant pipe 27 is sent.
  • a header connecting pipe other than the header connecting pipe is a switching valve having a function of connecting to the gas refrigerant pipe 28.
  • a rotary switching valve is used as the switching valve 80. This switching valve 80 is connected to the liquid refrigerant pipe 27, the refrigerant distribution pipe 64, the header communication pipes 65 a to 65 c and the gas refrigerant pipe 28.
  • FIG. 17 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation.
  • FIG. 18 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
  • the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 80 similar to that in the heating operation. Then, as shown in FIG. 18, a header other than the header communication pipe to which the refrigerant flowing through the liquid refrigerant pipe 27 is selected to be sent to any of the header communication pipes 65a to 65c and the refrigerant flowing through the liquid refrigerant pipe 27 is sent.
  • the heating defrost operation similar to that in the above embodiment or the first modification can be performed.
  • the number of parts constituting the defrost flow path mechanism 26 can be reduced as compared with the configurations of the above-described embodiment and the first modification, and further, the configurations of the second to fourth modifications.
  • the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a.
  • header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75 but is not limited thereto.
  • switching valves 81a to 81c in which branch pipe side heat exchange path selection valves 73a to 73c and header side heat exchange path selection valves 74a to 74c are integrated are used. Also good.
  • the switching valves 81a to 81c send the refrigerant flowing through the heat exchange path supply pipe 71 from the gas side end to the liquid side end of the heat exchange paths 31 to 33, or through the refrigerant distribution pipe 64.
  • This is a switching valve having a function of selecting whether or not the refrigerant that has passed through 31 to 33 from the liquid side end toward the gas side end is sent to the header 66.
  • three-way valves are used as the switching valves 81a to 81c.
  • These switching valves 81a to 81c are connected to the heat exchange path branch pipes 72a to 72c and the header communication pipes 65a to 65c. In the configuration of this modification, in the control block diagram of FIG.
  • FIG. 19 is a schematic configuration diagram of the air-conditioning apparatus 1 according to the present modification, and is a diagram illustrating the flow of the refrigerant in the air-conditioning apparatus 1 during the heating operation.
  • FIG. 20 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
  • switching is performed so that the refrigerant that has passed through the heat exchange paths 31 to 33 through the refrigerant distribution pipe 64 from the liquid side end to the gas side end is sent to the header 66.
  • the valves 81a to 81c By operating the valves 81a to 81c, the heating operation similar to that in the above embodiment can be performed. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valves 81a to 81c similar to that in the heating operation. Then, as shown in FIG. 20, any one of the switching valves 81a to 81c is operated so as to send the refrigerant flowing through the heat exchange path supply pipe 71 from the gas side end to the liquid side end of the heat exchange paths 31 to 33.
  • the other switching valve is operated by sending the refrigerant that has passed through the heat exchange paths 31 to 33 through the refrigerant distribution pipe 64 from the liquid side end toward the gas side end to the header 66.
  • a heating defrost operation similar to that of the first modification can be performed.
  • the configuration of the heating defrost operation according to the present invention is applied to the outdoor heat exchanger 23 having a plurality of heat exchange paths 31 to 33 connected in parallel to each other.
  • the heating defrost operation according to the present invention is applied not only to the plurality of heat exchange paths 31 to 33 but also to the outdoor heat exchanger 123 having the supercooling path 34 through which the refrigerant passes before flowing into the refrigerant distributor 64.
  • the following configuration may be applied. FIG.
  • the air conditioner 101 mainly includes an outdoor unit 102, an indoor unit 4, and a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6 that connect the outdoor unit 102 and the indoor unit 4.
  • the outdoor unit 102 and the indoor unit 4 constitute a refrigerant circuit 110 for performing a vapor compression refrigeration cycle by being connected via a liquid refrigerant communication pipe 5 and a gas refrigerant communication pipe 6.
  • the indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 110.
  • the indoor unit 4 mainly has an indoor heat exchanger 41. Note that the configuration of the indoor unit 4 is the same as the configuration of the indoor unit 4 of the first embodiment, and a description thereof will be omitted here.
  • the outdoor unit 102 is installed outside and constitutes a part of the refrigerant circuit 110.
  • the outdoor unit 102 mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 123, an expansion valve 24, an outdoor fan 25, and a defrost channel mechanism 126.
  • the configuration of the outdoor unit 102 is the same as the configuration of the outdoor unit 2 of the first embodiment except for the configuration of the outdoor heat exchanger 123 and the defrosting flow path mechanism 126.
  • the configuration of the 123 and the defrost flow path mechanism 126 will be described in detail.
  • the outdoor heat exchanger 123 is a heat exchanger that functions as a refrigerant radiator during cooling operation and functions as a refrigerant evaporator during heating operation.
  • a cross fin type fin-and-tube heat exchanger constituted by a heat transfer tube and a large number of fins is employed as the outdoor heat exchanger 123.
  • the outdoor heat exchanger 123 has a liquid side connected to the expansion valve 24 via a liquid refrigerant pipe 27 and a gas side connected to the four-way switching valve 22 via a gas refrigerant pipe 28. More specifically, the outdoor heat exchanger 123 is attached in a state where a large number of fins 61 and these fins 61 are penetrated in the plate thickness direction, like the outdoor heat exchanger 23 of the first embodiment.
  • FIG. 22 is a diagram schematically showing the outdoor heat exchanger 123 and the structure in the vicinity thereof.
  • the liquid side ends of the first to third heat exchange paths 31 to 33 are connected to the refrigerant distributor 64 via the first to third capillary tubes 63a to 63c, respectively.
  • the refrigerant flow divider 64 is a pipe member that joins the first to third capillary tubes 63a to 63c connected to the liquid side ends of the first to third heat exchange paths 31 to 33, and is a supercooling path-heat exchange path. It is connected to the communication pipe 35.
  • the gas side ends of the first to third heat exchange paths 31 to 33 are connected to the header 66 via first to third header communication pipes 65a to 65c, respectively.
  • the header 66 is a pipe member that joins the first to third header connecting pipes 65a to 65c connected to the gas side ends of the first to third heat exchange paths 31 to 33, and is connected to the gas refrigerant pipe 28. Yes.
  • the supercooling path 34 is connected in common to the liquid side ends of the first to third heat exchange paths 31 to 33.
  • the liquid side end of the supercooling path 34 is connected to the liquid refrigerant pipe 27.
  • the gas side end of the supercooling path 34 is connected to a supercooling path-heat exchange path connecting pipe 35.
  • the plurality of (here, three) heat exchange paths 31 to 33 constituting the outdoor heat exchanger 123 are connected in parallel to each other via the refrigerant flow divider 64 and the header 66.
  • the subcooling path 34 constituting the outdoor heat exchanger 123 is connected to the liquid side ends of the heat exchange paths 31 to 33 via the refrigerant flow divider 64 and the supercooling path-heat exchange path connecting pipe 35. .
  • all the heat exchange paths 31 to 33 function as a refrigerant radiator, and the supercooling path 34 functions as a refrigerant subcooler that radiates heat in the heat exchange paths 31 to 33. Further, during the heating operation, the supercooling path 34 functions as a radiator for the refrigerant in the intermediate pressure state after passing through the expansion valve 24 to prevent frosting at the bottom of the outdoor heat exchanger 123, and The heat exchange paths 31 to 33 function as a refrigerant evaporator.
  • the defrost flow path mechanism 126 passes a plurality of heat exchange paths without allowing the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 to flow into the refrigerant flow divider 64 after passing through the supercooling path 34. It is a mechanism for sending to the gas side end of the heat exchange path arbitrarily selected from 31 to 33.
  • the defrost flow path mechanism 126 is provided to perform a heating defrost operation described later. In this heating defrost operation, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 while defrosting any of the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 123. It is the operation which evaporates.
  • the defrost flow path mechanism 126 mainly includes a heat exchange path supply pipe 71, a plurality (here, three) heat exchange path branch pipes 72a to 72c, and a plurality (here, three) branch pipe side heat.
  • the heat exchange path supply pipe 71 passes the supercooling path ⁇ after the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 passes through the supercooling path 34 and before flowing into the refrigerant distributor 64. It is a refrigerant pipe for branching from the heat exchange path connecting pipe 35. One end of the heat exchange path supply pipe 71 is connected to a portion of the supercooling path-heat exchange path connecting pipe 35 between the gas side end of the supercooling path 34 and the refrigerant flow divider 64, and the other end.
  • the heat exchange path branch pipes 72a to 72c are connected.
  • the first to third heat exchange path branch pipes 72a to 72c are refrigerant pipes for supplying the refrigerant flowing through the heat exchange path supply pipe 71 to the gas side ends of the first to third heat exchange paths 31 to 33.
  • Each of the first to third heat exchange path branch pipes 72a to 72c has one end connected to the heat exchange path supply pipe 71 and the other end connected to the first to third header communication pipes 65a to 65c. Yes.
  • the first to third branch pipe side heat exchange path selection valves 73a to 73c, together with the first to third header side heat exchange path selection valves 74a to 74c, allow the refrigerant flowing through the heat exchange path supply pipe 71 to pass through the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to.
  • the first to third branch pipe side heat exchange path selection valves 73a to 73c are provided in the first to third heat exchange path branch pipes 72a to 72c, respectively. During the cooling operation and the heating operation, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed.
  • the branch pipe side heat exchange path selection valve corresponding to the heat exchange path for defrosting among the first to third branch pipe side heat exchange path selection valves 73a to 73c is opened.
  • the branch pipe side heat exchange path selection valve corresponding to the heat exchange path is closed.
  • the first to third header side heat exchange path selection valves 74a to 74c, together with the first to third branch pipe side heat exchange path selection valves 73a to 73c, transfer the refrigerant flowing through the heat exchange path supply pipe 71 to the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to.
  • the first to third header side heat exchange path selection valves 74a to 74c are connected to the other ends of the first to third heat exchange path branch pipes 72a to 72c among the first to third header communication pipes 65a to 65c, respectively. It is provided in a portion between the position and the header 66.
  • all of the first to third header side heat exchange path selection valves 74a to 74c are opened.
  • the header side heat exchange path selection valve corresponding to the heat exchange path for defrosting is closed among the first to third header side heat exchange path selection valves 74a to 74c, and the other heat exchanges are performed.
  • the header side heat exchange path selection valve corresponding to the path can be opened.
  • the shunt pipe side selection valve 75 is configured to pass the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 after passing through the supercooling path 34 and before flowing into the refrigerant flow divider 64. It is a solenoid valve for selecting whether or not to branch from the heat exchange path connecting pipe 35.
  • the branch pipe side selection valve 75 is provided in a portion between the position where the heat exchange path supply pipe 71 is branched in the supercooling path-heat exchange path connecting pipe 35 and the refrigerant distributor 64. And the shunt pipe side selection valve 75 is opened at the time of air_conditionaing
  • the operation of the air conditioner 101 includes a cooling operation that cools the room, a heating operation that only heats the room, and a heating defrost operation that heats the room while defrosting the outdoor heat exchanger 23. .
  • FIG. 23 is a diagram illustrating the flow of the refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 24 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during heating / defrosting operation (when defrosting the first heat exchange path 31).
  • FIG. 25 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation.
  • the cooling operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the outdoor heat exchanger 123, the indoor heat exchanger 41, and the compressor 21.
  • the outdoor heat exchanger 123 functions as a refrigerant radiator
  • the indoor heat exchanger 41 functions as a refrigerant evaporator, thereby cooling indoor air.
  • the outdoor heat exchanger 123 functions as a refrigerant radiator and the indoor heat exchanger 41 functions as a refrigerant evaporator (that is, indicated by the solid line of the four-way switching valve 22 in FIG. 21).
  • the four-way selector valve 22 is switched so that Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126.
  • the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle.
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 123 through the four-way switching valve 22.
  • the high-pressure refrigerant discharged from the compressor 21 passes through the four-way switching valve 22, the gas refrigerant pipe 28, the header 66, the header communication pipes 65a to 65c, and the header side heat exchange path selection valves 74a to 74c. It is sent to the gas side ends of the heat exchange paths 31 to 33 of the heat exchanger 123.
  • the high-pressure refrigerant sent to the gas side ends of the heat exchange paths 31 to 33 performs heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33 to radiate heat.
  • the high-pressure refrigerant that has radiated heat in the heat exchange paths 31 to 33 flows from the liquid side ends of the heat exchange paths 31 to 33, capillary tubes 63a to 63c, refrigerant flow divider 64, supercooling path-heat exchange path connecting pipe 35, And, it is sent to the gas side end of the supercooling path 34 of the outdoor heat exchanger 123 through the branch pipe side selection valve 75.
  • the high-pressure refrigerant sent to the gas side end of the supercooling path 34 further dissipates heat by exchanging heat with the outdoor air supplied by the outdoor fan 25 in the supercooling path 34.
  • the high-pressure refrigerant supercooled in the supercooling path 34 is sent to the expansion valve 24 through the liquid refrigerant pipe 27.
  • the refrigerant sent to the expansion valve 24 is depressurized to a low pressure in the refrigeration cycle.
  • the low-pressure refrigerant decompressed by the expansion valve 24 is sent to the indoor heat exchanger 41 through the liquid refrigerant communication pipe 5.
  • the low-pressure refrigerant sent to the indoor heat exchanger 41 evaporates by exchanging heat with indoor air in the indoor heat exchanger 41.
  • the low-pressure refrigerant evaporated in the indoor heat exchanger 41 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6 and the four-way switching valve 22.
  • the heating operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 123, and the compressor 21.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • the outdoor heat exchanger 123 functions as a refrigerant evaporator, thereby heating indoor air.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • the outdoor heat exchanger 123 functions as a refrigerant evaporator (that is, the four-way switching valve 22 in FIGS. 21 and 23).
  • the four-way switching valve 22 is switched so as to be in a state indicated by a broken line.
  • first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126.
  • the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle.
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22.
  • the high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41.
  • the high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication pipe 5 and reduced to an intermediate pressure in the refrigeration cycle.
  • the intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123 through the liquid refrigerant pipe 27.
  • the intermediate-pressure refrigerant sent to the liquid side end of the supercooling path 34 radiates heat by exchanging heat with the outdoor air supplied by the outdoor fan 25 in the supercooling path 34, thereby performing outdoor heat exchange. Frost formation at the bottom of the vessel 123 is prevented.
  • the low-pressure refrigerant radiated in the supercooling path 34 is supplied from the gas side end of the supercooling path 34 to the supercooling path-heat exchange path connecting pipe 35, the diversion pipe side selection valve 75, the refrigerant flow divider 64, and the capillary It is sent to the liquid side ends of the heat exchange paths 31 to 33 of the outdoor heat exchanger 23 through the tubes 63a to 63c.
  • the low-pressure refrigerant sent to the liquid side ends of the heat exchange paths 31 to 33 evaporates through heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33.
  • the low-pressure refrigerant evaporated in the heat exchange paths 31 to 33 flows from the gas side ends of the heat exchange paths 31 to 33 to the header communication pipes 65a to 65c, the header side heat exchange path selection valves 74a to 74c, the header 66, and the gas.
  • the refrigerant is again sucked into the compressor 21 through the refrigerant pipe 28 and the four-way switching valve 22.
  • the heating defrost operation is performed by circulating the refrigerant in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 123, and the compressor 21, In this operation, the outdoor heat exchanger 123 is defrosted.
  • the indoor heat exchanger 41 functions as a refrigerant radiator
  • any one of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 is a refrigerant radiator.
  • the remaining heat exchange paths 31 to 33 function as a refrigerant evaporator. Accordingly, the indoor air is heated while the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 are sequentially defrosted.
  • the switching state of the four-way switching valve 22 in the heating defrost operation is the same as in the heating operation. That is, the four-way switching valve 22 is in a state where the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 123 functions as a refrigerant evaporator (that is, the four-way valves in FIGS. 21 and 24). The state shown by the broken line of the switching valve 22). Further, since the defrosting of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 is sequentially performed, the selection valves 73a to 73c, 74a to 74c, and 75 are different from those during the cooling operation and the heating operation. Switch to open / closed state.
  • the refrigerant flows through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126.
  • the operation during the heating defrost operation will be described in detail including the procedure from the start to the end of the heating defrost operation.
  • step S1 it is determined whether or not the amount of frost formation in the outdoor heat exchanger 123 has increased due to the heating operation, and defrosting is necessary. In addition, since determination of whether this defrost is required is the same as that of step S1 of the heating defrost operation of 1st Embodiment, description is abbreviate
  • steps S2 to S7 the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 are sequentially defrosted.
  • the defrosting of the first to third heat exchange paths 31 to 33 may basically be arbitrarily selected, but the flow of drain water generated by the defrosting to the bottom plate 52 of the unit casing 51 is considered.
  • defrosting shall be performed in the order of the first heat exchange path 31, the second heat exchange path 32, and the third heat exchange path 33.
  • the defrosting (step S2) of the first heat exchange path 31 is performed by switching the open / close states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 126. Specifically, the first branch pipe side heat exchange path selection valve 73a is opened, the second and third branch pipe side heat exchange path selection valves 73b and 73c are closed, and the first header side heat exchange path selection valve 74a is closed. Is closed, the second and third header side heat exchange path selection valves 74b and 74c are opened, and the flow dividing pipe side selection valve 75 is switched to a closed state.
  • the first branch pipe side heat exchange path selection valve 73a is opened and the first header side heat exchange path is opened.
  • a switching operation for closing the selection valve 74a and closing the branch pipe side selection valve 75 is performed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the first heat exchange path branch pipe 72a of the defrost flow path mechanism 126.
  • the low-pressure refrigerant (see point A in FIGS. 24 and 25) in the refrigeration cycle is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle (See point B in FIGS. 24 and 25).
  • the high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22.
  • the high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41 (see point C in FIGS. 24 and 25). Up to this point, it is the same as in the heating operation.
  • the high-pressure refrigerant that has radiated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and is reduced to a pressure between the high pressure and the low pressure (hereinafter referred to as intermediate pressure) in the refrigeration cycle. (See point D in FIGS. 24 and 25).
  • the intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123.
  • the intermediate-pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the first heat exchange path 31 in the supercooling path 34 and flows down to the bottom of the outdoor heat exchanger 123. Water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan (see point D ′ in FIGS. 24 and 25). Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed.
  • the intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the first heat exchange path branch pipe 72a, the first branch pipe side heat exchange path selection valve 73a, and the first header communication pipe 65a. It is sent to the gas side end of the first heat exchange path 31 of the heat exchanger 123.
  • all the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 is sent to the gas side end of the first heat exchange path 31 without flowing into the refrigerant flow divider 64.
  • the intermediate-pressure refrigerant sent to the gas side end of the first heat exchange path 31 passes through the first heat exchange path 31 from the gas side end of the first heat exchange path 31 toward the liquid side end, Frost adhering to the first heat exchange path 31 of the outdoor heat exchanger 123 is melted (see point E in FIGS. 24 and 25). Thereby, defrosting of the 1st heat exchange path 31 of the outdoor heat exchanger 23 is performed.
  • the intermediate-pressure refrigerant that has passed through the first heat exchange path 31 is sent from the liquid side end of the first heat exchange path 31 to the refrigerant flow divider 64 through the first capillary tube 63a.
  • the first capillary tube 63a flows an intermediate-pressure refrigerant having a larger flow rate than that during the cooling operation or the heating operation. Therefore, the first capillary tube 63a has a pressure loss as compared with the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure in the refrigeration cycle (that is, the pressure at point E in FIGS. 24 and 25) and the low pressure (see point F in FIGS. 24 and 25).
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the second and third capillary tubes 63b, because the flow dividing pipe side selection valve 75 is closed.
  • the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the second and third capillary tubes 63b and 63c (see point G in FIGS. 24 and 25).
  • the low-pressure refrigerant sent to the liquid side ends of the second and third heat exchange paths 32, 33 is second from the liquid side ends of the second and third heat exchange paths 32, 33 toward the gas side ends. Then, it passes through the third heat exchange paths 32 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25 (see point A in FIGS. 24 and 25).
  • the low-pressure refrigerant evaporated in the second and third heat exchange paths 32 and 33 is supplied from the gas side ends of the second and third heat exchange paths 32 and 33 to the second and third header communication pipes 65b, 65c,
  • the air is again sucked into the compressor 21 through the second and third header side heat exchange path selection valves 74b and 74c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22.
  • defrosting of the first heat exchange path 31 is started while continuing the indoor heating.
  • defrosting of the 1st heat exchange path 31 is performed until defrosting of the 1st heat exchange path 31 is completed (step S3).
  • the defrosting (step S4) of the second heat exchange path 32 is performed by switching the open / closed states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 126 in the same manner as the first heat exchange path 31. Done. Specifically, the second branch pipe side heat exchange path selection valve 73b is opened, the first and third branch pipe side heat exchange path selection valves 73a and 73c are closed, and the second header side heat exchange path selection valve 74b. Is closed, the first and third header side heat exchange path selection valves 74a and 74c are opened, and the branch pipe side selection valve 75 is switched to a closed state.
  • the second branch pipe side heat exchange path selection valve 73b is opened, A switching operation is performed in which the first branch pipe side heat exchange path selection valve 73a is closed, the first header side heat exchange path selection valve 74a is opened, and the second header side heat exchange path selection valve 74b is closed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the second heat exchange path branch pipe 72b of the defrost flow path mechanism 126.
  • the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same manner as in the defrosting of the first heat exchange path 31, and in the indoor heat exchanger 41.
  • Heat is exchanged with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends it to the outdoor heat exchanger 123.
  • the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123.
  • the intermediate pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the second heat exchange path 32 in the supercooling path 34 and flows down to the bottom of the outdoor heat exchanger 123.
  • the water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan. Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed.
  • the intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the second heat exchange path branch pipe 72b, the second branch pipe side heat exchange path selection valve 73b, and the second header communication pipe 65b. It is sent to the gas side end of the second heat exchange path 32 of the heat exchanger 123.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 is all sent to the gas side end of the second heat exchange path 32 without flowing into the refrigerant flow divider 64.
  • the intermediate-pressure refrigerant sent to the gas side end of the second heat exchange path 32 passes through the second heat exchange path 32 from the gas side end of the second heat exchange path 32 toward the liquid side end,
  • the frost attached to the second heat exchange path 32 of the outdoor heat exchanger 123 is melted.
  • defrosting of the 2nd heat exchange path 32 of the outdoor heat exchanger 123 is performed.
  • the intermediate-pressure refrigerant that has passed through the second heat exchange path 32 is sent from the liquid side end of the second heat exchange path 32 to the refrigerant flow divider 64 through the second capillary tube 63b.
  • the second capillary tube 63b has a flow rate of intermediate pressure refrigerant that is larger than that during cooling operation or heating operation.
  • the second capillary tube 63b has a pressure loss as compared with the case where the refrigerant flows during cooling operation or heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle.
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and third capillary tubes 63a, since the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the first and third heat exchange paths 31, 33. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and third capillary tubes 63a and 63c.
  • the low-pressure refrigerant sent to the liquid side ends of the first and third heat exchange paths 31 and 33 is first from the liquid side ends of the first and third heat exchange paths 31 and 33 toward the gas side end. And passes through the third heat exchange paths 31 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. Then, the low-pressure refrigerant evaporated in the first and third heat exchange paths 31 and 33 flows from the gas side ends of the first and third heat exchange paths 31 and 33 to the first and third header communication pipes 65a and 65c, The air is again sucked into the compressor 21 through the first and third header side heat exchange path selection valves 74 a and 74 c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the second heat exchange path 32 is started while continuing the indoor heating. And the defrosting of the 2nd heat exchange path 32 is performed until the defrosting of the 2nd heat exchange path 32 is completed (step S5).
  • the defrosting (step S6) of the third heat exchange path 33 is performed by opening and closing the selection valves 73a to 73c, 74a to 74c, and 75 of the defrost flow path mechanism 126, similarly to the first and second heat exchange paths 31 and 32. This is done by switching the state. Specifically, the third branch pipe side heat exchange path selection valve 73c is opened, the first and second branch pipe side heat exchange path selection valves 73a and 73b are closed, and the third header side heat exchange path selection valve 74c is closed. Is closed, the first and second header side heat exchange path selection valves 74a and 74b are opened, and the branch pipe side selection valve 75 is switched to a closed state.
  • the third branch pipe side heat exchange path selection valve 73c is opened, A switching operation is performed in which the second branch pipe side heat exchange path selection valve 73b is closed, the second header side heat exchange path selection valve 74b is opened, and the third header side heat exchange path selection valve 74c is closed.
  • the refrigerant flows into the heat exchange path supply pipe 71 and the third heat exchange path branch pipe 72c of the defrost flow path mechanism 126.
  • the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same way as when the first and second heat exchange paths 31 and 32 are defrosted.
  • the heat exchanger 41 performs heat exchange with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends the heat to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123.
  • the intermediate pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the second heat exchange path 33 in the supercooling path 34 and flows down to the lowermost part of the outdoor heat exchanger 123.
  • the water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan. Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed.
  • the intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35.
  • the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the third heat exchange path branch pipe 72c, the third branch pipe side heat exchange path selection valve 73c, and the third header communication pipe 65c. It is sent to the gas side end of the third heat exchange path 33 of the heat exchanger 23.
  • the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the third heat exchange path 33 without flowing into the refrigerant flow divider 64.
  • the intermediate pressure refrigerant sent to the gas side end of the third heat exchange path 33 passes through the third heat exchange path 33 from the gas side end of the third heat exchange path 33 toward the liquid side end,
  • the frost attached to the third heat exchange path 33 of the outdoor heat exchanger 123 is melted. Thereby, defrosting of the 3rd heat exchange path 33 of the outdoor heat exchanger 123 is performed.
  • the intermediate-pressure refrigerant that has passed through the third heat exchange path 33 is sent from the liquid side end of the third heat exchange path 33 to the refrigerant flow divider 64 through the third capillary tube 63c.
  • an intermediate pressure refrigerant having a larger flow rate than in the cooling operation or the heating operation flows, so that the pressure loss is smaller than that in the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle.
  • the low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and second capillary tubes 63a, because the flow dividing pipe side selection valve 75 is closed. Branched to 63 b and sent to the liquid side ends of the first and second heat exchange paths 31 and 32.
  • the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and second capillary tubes 63a and 63b.
  • the low-pressure refrigerant sent to the liquid side ends of the first and second heat exchange paths 31 and 32 is first from the liquid side ends of the first and second heat exchange paths 31 and 32 toward the gas side ends. Then, it passes through the second heat exchange paths 31 and 32 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25.
  • the low-pressure refrigerant evaporated in the first and second heat exchange paths 31 and 32 flows from the gas side ends of the first and second heat exchange paths 31 and 32 to the first and second header communication pipes 65a and 65b, The air is again sucked into the compressor 21 through the first and second header side heat exchange path selection valves 74a and 74b, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the third heat exchange path 33 is started while continuing the indoor heating. And the defrosting of the 3rd heat exchange path 33 is performed until the defrosting of the 2nd heat exchange path 33 is completed (step S7).
  • step S8 the heating operation is resumed (step S8).
  • Evaporative heating operation is performed.
  • the heating defrost operation is sequentially performed on the plurality of heat exchange paths 31 to 33, so that the entire outdoor heat exchanger 123 is defrosted while the indoor heating is continued.
  • the drain water that has melted by the defrosting of the heat exchange paths 31 to 33 and has flowed to the bottom of the outdoor heat exchanger 123 is heated.
  • the drain water is prevented from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan.
  • the entire flow rate of the refrigerant compressed in the compressor 21 is sent to the indoor heat exchanger 41 and used for heating (FIG. 24). And the process from point B to point C in FIG. 25), and then defrosting can be performed by the heat of the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 (see FIGS. 24 and 25). (See the process from point D to point E). For this reason, in the heating defrost operation of the air conditioner 101, the outdoor heat exchanger 123 can be defrosted with almost no reduction in heating capacity.
  • the defrosting flow path mechanism 126 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto. For example, as shown in FIGS.
  • the heat exchange path branch pipes 72a to 72c, the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the header 66 Alternatively, a switching valve 82 that integrates the above may be used.
  • the switching valve 82 selects which of the header communication pipes 65a to 65c sends the refrigerant flowing through the heat exchange path supply pipe 71, and the header communication pipe through which the refrigerant flowing through the heat exchange path supply pipe 71 is sent.
  • the other header communication pipes are switching valves having a function of connecting to the gas refrigerant pipe 28 or selecting not to send the refrigerant to any of the header communication pipes 65a to 65c.
  • FIG. 26 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 27 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
  • the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 82 as in the heating operation. Then, as shown in FIG. 27, it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent.
  • the heating defrost operation similar to that in the above embodiment or the first modification can be performed. And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, the number of parts which comprise the flow-path mechanism 126 for defrost can be reduced.
  • the defrosting flow path mechanism 126 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a.
  • the header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75 are not limited thereto.
  • a switching valve 83 in which 74a to 74c, the branch pipe side selection valve 75, and the header 66 are integrated may be used.
  • the switching valve 83 selects whether the refrigerant flowing through the supercooling path-heat exchange path connecting pipe 35 flows to the refrigerant distribution pipe 64 or the header connecting pipes 65a to 65c, and the supercooling path
  • a header connecting pipe other than the header connecting pipe to which the refrigerant flowing through the heat exchange path connecting pipe 35 is sent is a switching valve having a function of connecting to the gas refrigerant pipe 28.
  • a rotary type switching valve is used as the switching valve 83.
  • the switching valve 83 is connected to the supercooling path-heat exchange path connecting pipe 35, the refrigerant branch pipe 64, the header connecting pipes 65 a to 65 c, and the gas refrigerant pipe 28.
  • switching is performed in place of the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the branch pipe side selection valve 75 in the control block diagram of FIG.
  • a valve 83 is connected to the control unit 8.
  • FIG. 28 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 29 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
  • the above embodiment is implemented.
  • the same heating operation can be performed.
  • the same cooling operation as that in the above embodiment can be performed in the operation state of the switching valve 83 similar to that in the heating operation.
  • the refrigerant flowing through the supercooling path-heat exchange path connecting pipe 35 is selected to be sent to any of the header connecting pipes 65a to 65c, and the refrigerant flowing through the liquid refrigerant pipe 27 is sent.
  • the heating defrost operation similar to that in the above embodiment or the first modification can be performed. And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, and the structure of the modification 2, the number of parts which comprise the flow-path mechanism 126 for defrost can be reduced.
  • the defrost flow path mechanism 126 may be configured so as to obtain the above flow.
  • the heat exchange path supply pipe 71 is connected between the expansion valve 24 of the liquid refrigerant pipe 27 and the liquid side end of the supercooling path 34.
  • the electromagnetic valve 76 may be provided in the heat exchange path supply pipe 71 so as to be branched from the position.
  • the solenoid valve together with the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the branch pipe side selection valve 75 are provided.
  • 76 is connected to the control unit 8.
  • FIG. 30 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 31 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
  • the heating operation similar to that in the above embodiment can be performed by opening the branch pipe side selection valve 75 and closing the electromagnetic valve 76. Further, in the operation state of the branch pipe side selection valve 75 and the electromagnetic valve 76 similar to those in the heating operation, the same cooling operation as in the above embodiment can be performed. And as shown in FIG. 31, the heating defrost similar to 1st Embodiment is made without passing a refrigerant
  • the defrosting channel mechanism 126 passes the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 through the supercooling path 34, and then the refrigerant distributor.
  • the flow is configured to be sent to the gas side end of a heat exchange path arbitrarily selected from the plurality of heat exchange paths 31 to 33 without flowing into the heat exchange path.
  • the same refrigerant as in the heating defrost operation of the first embodiment may be configured so as to obtain the above flow.
  • FIGS. 32 and 33 in the air conditioner 101 of the second modification, the heat exchange path supply pipe 71 is connected between the expansion valve 24 of the liquid refrigerant pipe 27 and the liquid side end of the supercooling path 34. You may make it branch from the position of.
  • a switching valve 82 is connected to the control unit 8.
  • FIG. 32 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 33 is a diagram showing a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
  • the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 82 as in the heating operation. Then, as shown in FIG.
  • the branch pipe side selection valve 75 is closed, the refrigerant flowing through the heat exchange path supply pipe 71 is selected to be sent to any one of the header communication pipes 65a to 65c, and the heat exchange is performed.
  • the switching valve 82 By operating the switching valve 82 to connect the header communication pipe other than the header communication pipe through which the refrigerant flowing through the path supply pipe 71 is connected to the gas refrigerant pipe 28, the refrigerant does not pass through the supercooling path 34.
  • a heating defrost operation similar to that of the first embodiment can be performed.
  • the defrosting flow path mechanism 126 passes the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 through the supercooling path 34, and then the refrigerant distributor.
  • the flow is configured to be sent to the gas side end of a heat exchange path arbitrarily selected from the plurality of heat exchange paths 31 to 33 without flowing into the heat exchange path.
  • the same refrigerant as in the heating defrost operation of the first embodiment may be configured so as to obtain the above flow.
  • FIGS. 34 and 35 in the air conditioner 101 according to the third modification, the liquid refrigerant pipe 27 is connected to the switching valve 83 instead of the supercooling path-heat exchange path connecting pipe 35. Also good.
  • a switching valve 83 is connected to the control unit 8.
  • FIG. 34 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation.
  • FIG. 35 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
  • the above embodiment is implemented.
  • the same heating operation can be performed.
  • the same cooling operation as that in the above embodiment can be performed in the operation state of the switching valve 83 similar to that in the heating operation.
  • it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the liquid refrigerant pipe 27 is sent to, and a header other than the header communication pipe to which the refrigerant flowing through the liquid refrigerant pipe 27 is sent.
  • the defrost flow path mechanisms 26, 126 are configured to include a heat exchange path supply pipe 71 and heat exchange path branch pipes 72a to 72c.
  • a configuration having a header 68 may be employed in place of the heat exchange path supply pipe 71 and the heat exchange path branch pipes 72a to 72c.
  • FIG. 36 shows an example in which the defrost flow path mechanism 26 having the header 68 is adopted in the configuration of the first embodiment. However, in the configuration of the second embodiment, as shown in FIG.
  • the defrosting flow path mechanism 126 in which the header 68 is directly connected to the supercooling path-heat exchange path connecting pipe 35 may be employed.
  • a configuration in which a plurality of indoor units are connected to the outdoor unit a configuration in which one indoor unit is connected to the plurality of outdoor units, or a configuration in which a plurality of indoor units are connected to the plurality of outdoor units may be employed. .
  • the said embodiment and its modification although it was an air conditioning apparatus which can switch between cooling and heating with a four-way switching valve, it is not limited to this.
  • a configuration dedicated to heating that is, a configuration in which an indoor heat exchanger is always used as a radiator without a four-way switching valve
  • a configuration dedicated to heating that is, a configuration in which an indoor heat exchanger is always used as a radiator without a four-way switching valve
  • the outdoor unit of the type which blows off outdoor air to a horizontal direction is employ
  • adopted it is not limited to this.
  • other types of outdoor units such as an outdoor unit that blows outdoor air upward by installing an outdoor fan above the outdoor heat exchanger may be used.
  • cross fin type fin and tube type heat exchanger adopted as an outdoor heat exchanger, it is not limited to this.
  • another type of heat exchanger may be used such as a laminated heat exchanger using corrugated fins.
  • the number of heat exchange paths constituting the outdoor heat exchanger is not limited to three, and may be four or more.
  • the present invention is widely applicable to an air conditioner capable of performing a heating operation.

Abstract

An air conditioner (1) is provided with a flow path mechanism (26) used for defrosting. The air conditioner (1) performs a heating-defrost operation whereby the refrigerant transmitted from an indoor heat exchanger (41) to an outdoor heat exchanger (23) is evaporated while a given heat exchange path is defrosted by means of the defrosting flow path mechanism (26). In the heating-defrost operation, first, by means of the defrosting flow path mechanism (26), the refrigerant transmitted from the indoor heat exchanger (41) to the outdoor heat exchanger (23) is circulated in a given heat exchange path from the gas-side end toward the liquid-side end of the given heat exchange path, without being introduced into a refrigerant flow divider (64). Next, the refrigerant that has passed through the given heat exchange path is passed through the refrigerant flow divider (64) and is circulated from the liquid-side end to the gas-side end in another heat exchange path other than the given heat exchange path.

Description

空気調和装置Air conditioner
　本発明は、空気調和装置、特に、暖房運転を行うことが可能な空気調和装置に関する。 The present invention relates to an air conditioner, and more particularly to an air conditioner capable of performing a heating operation.
　従来より、圧縮機と室内熱交換器と室外熱交換器とが順次接続されることによって構成されており、圧縮機、室内熱交換器、室外熱交換器、圧縮機の順に冷媒を循環させる暖房運転を行うことが可能な空気調和装置がある。この空気調和装置では、室外熱交換器に着霜が発生した場合に、四路切換弁等によって、圧縮機、室外熱交換器、室内熱交換器、圧縮機の順に冷媒を循環させるように切り換えて室外熱交換器の除霜を行う逆サイクルデフロスト運転が行われる。このため、この空気調和装置では、逆サイクルデフロスト運転中に暖房運転が停止してしまい、室内における快適性が損なわれる。
　このようなデフロスト運転中の暖房運転の停止という状況を改善するために、暖房運転を継続しながら室外熱交換器の除霜を行うデフロスト方式として、特許文献１（特開２０００－２７４７８０号公報）、及び、特許文献２（特開２００１－０５９９９４号公報）に示すような空気調和装置が提案されている。 Conventionally, a compressor, an indoor heat exchanger, and an outdoor heat exchanger are connected in order, and heating is performed by circulating a refrigerant in the order of the compressor, the indoor heat exchanger, the outdoor heat exchanger, and the compressor. There is an air conditioner that can be operated. In this air conditioner, when frost is generated in the outdoor heat exchanger, the refrigerant is switched in the order of the compressor, the outdoor heat exchanger, the indoor heat exchanger, and the compressor by a four-way switching valve or the like. The reverse cycle defrost operation is performed to defrost the outdoor heat exchanger. For this reason, in this air conditioner, the heating operation stops during the reverse cycle defrost operation, and the comfort in the room is impaired.
In order to improve such a situation of stopping the heating operation during the defrost operation, Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-274780) discloses a defrost method for defrosting the outdoor heat exchanger while continuing the heating operation. And an air conditioner as shown in Patent Document 2 (Japanese Patent Laid-Open No. 2001-059994) has been proposed.
　特許文献１の空気調和装置では、室外熱交換器の複数の熱交パスの液側端のそれぞれに電磁弁を設けるようにしている。そして、この空気調和装置では、室外熱交換器に着霜が発生した場合には、任意に選択された熱交パスの電磁弁を閉止することで、この熱交パス内における冷媒の流れを止める運転を行うようにしている。この運転によって、この空気調和装置では、室外空気の熱によって任意の熱交パスの除霜を行いつつ、他の熱交パスにおいて冷媒を蒸発させることで暖房運転を継続できるようにしている。
　特許文献２の空気調和装置では、圧縮機から吐出された冷媒の一部を、室内熱交換器に送らずに室外熱交換器の複数の熱交パスの液側端に送るためのバイパス路を設けるようにしている。そして、この空気調和装置では、室外熱交換器に着霜が発生した場合には、バイパス路を通じて、圧縮機から吐出された冷媒の一部を、室内熱交換器に送らずに室外熱交換器の任意の熱交パスに送る運転を行うようにしている。この運転によって、この空気調和装置では、バイパス路を通じて任意の熱交パスに送られる冷媒の熱によって任意の熱交パスの除霜を行いつつ、他の熱交パスにおいて冷媒を蒸発させることで暖房運転を継続できるようにしている。 In the air conditioner of Patent Document 1, an electromagnetic valve is provided at each of the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger. In this air conditioner, when frost formation occurs in the outdoor heat exchanger, the flow of the refrigerant in the heat exchange path is stopped by closing the electromagnetic valve of the heat exchange path arbitrarily selected. I try to drive. With this operation, in this air conditioner, the heating operation can be continued by defrosting an arbitrary heat exchange path with the heat of the outdoor air and evaporating the refrigerant in another heat exchange path.
In the air conditioner of Patent Document 2, a bypass path for sending a part of the refrigerant discharged from the compressor to the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger without sending it to the indoor heat exchanger is provided. I am trying to provide it. And in this air conditioner, when frost formation has occurred in the outdoor heat exchanger, the outdoor heat exchanger is not sent to the indoor heat exchanger through the bypass passage, without sending a part of the refrigerant discharged from the compressor. The operation is sent to any heat exchange path. With this operation, in this air conditioner, heating is performed by evaporating the refrigerant in another heat exchange path while defrosting the arbitrary heat exchange path by the heat of the refrigerant sent to the arbitrary heat exchange path through the bypass. The operation can be continued.
　しかし、上記特許文献１のデフロスト方式では、室外空気の温度が０℃以下の場合には霜（氷）が溶けないため、大きな暖房負荷が必要となる外気温度が０℃以下の気象条件において、室外熱交換器の除霜ができないという問題がある。また、霜の温度との温度差が小さい室外空気によって霜を溶かすため、除霜に時間がかかってしまい、その結果、暖房運転だけを行っている時間が短くなり、積分的な暖房能力を高めることができないという問題がある。
　また、上記特許文献２のデフロスト方式では、室内熱交換器に送られて暖房に使用される冷媒の一部を室外熱交換器の除霜に使用するため、除霜中の暖房能力が非常に低下してしまうという問題がある。
　本発明の課題は、暖房運転を行うことが可能な空気調和装置において、暖房能力をほとんど低下させることなく、室外熱交換器の除霜を行えるようにすることにある。 However, in the defrost method of the above-mentioned Patent Document 1, since the frost (ice) does not melt when the temperature of the outdoor air is 0 ° C. or less, in the weather conditions where the outside air temperature requiring a large heating load is 0 ° C. or less, There is a problem that the outdoor heat exchanger cannot be defrosted. In addition, since the frost is melted by outdoor air having a small temperature difference from the frost temperature, it takes time to defrost, and as a result, the time during which only the heating operation is performed is shortened, and the integral heating capacity is increased. There is a problem that can not be.
Moreover, in the defrost system of the said patent document 2, since a part of refrigerant | coolant sent to an indoor heat exchanger and used for heating is used for defrosting of an outdoor heat exchanger, the heating capability during a defrost is very much. There is a problem that it falls.
An object of the present invention is to enable an outdoor heat exchanger to be defrosted in an air-conditioning apparatus capable of performing a heating operation with almost no decrease in heating capacity.
　第１の観点にかかる空気調和装置は、冷媒を圧縮する圧縮機と、圧縮機において圧縮された冷媒の放熱を行う室内熱交換器と、室内熱交換器において放熱した冷媒を室外空気との熱交換によって蒸発させる室外熱交換器と、が順次接続されることによって構成されている。この空気調和装置は、圧縮機、室内熱交換器、室外熱交換器、圧縮機の順に冷媒を循環させる暖房運転を行うことが可能である。室外熱交換器は、互いが並列に接続された複数の熱交パスを有している。複数の熱交パスの液側端は、室内熱交換器から室外熱交換器に送られる冷媒を複数の熱交パスの液側端に分岐するための冷媒分流器によって並列に接続されている。そして、この空気調和装置には、上記の構成を前提として、室内熱交換器から室外熱交換器に送られる冷媒を、冷媒分流器に流入させることなく、複数の熱交パスのうち任意に選択された熱交パスのガス側端に送るためのデフロスト用流路機構がさらに設けられている。そして、この空気調和装置では、デフロスト用流路機構によって、任意の熱交パスの除霜を行いつつ、室内熱交換器から室外熱交換器に送られる冷媒を蒸発させる暖房デフロスト運転を行うようになっている。この暖房デフロスト運転は、まず、室内熱交換器から室外熱交換器に送られる冷媒を、デフロスト用流路機構によって、冷媒分流器に流入させることなく、任意の熱交パスのガス側端から液側端に向かって任意の熱交パス内を通過させる。次に、任意の熱交パスを通過した冷媒を、冷媒分流器を通じて、任意の熱交パス以外の他の熱交パスの液側端からガス側端に向かって他の熱交パス内を通過させる。 An air conditioner according to a first aspect includes a compressor that compresses a refrigerant, an indoor heat exchanger that dissipates heat of the refrigerant compressed in the compressor, and heat generated by the indoor heat exchanger that radiates heat from the outdoor air. An outdoor heat exchanger that evaporates by exchange is sequentially connected. This air conditioner can perform a heating operation in which refrigerant is circulated in the order of a compressor, an indoor heat exchanger, an outdoor heat exchanger, and a compressor. The outdoor heat exchanger has a plurality of heat exchange paths connected to each other in parallel. The liquid side ends of the plurality of heat exchange paths are connected in parallel by a refrigerant shunt for branching the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to the liquid side ends of the plurality of heat exchange paths. The air conditioner is arbitrarily selected from a plurality of heat exchange paths without allowing the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to flow into the refrigerant distributor, on the premise of the above configuration. There is further provided a defrost flow path mechanism for sending to the gas side end of the heat exchange path. In this air conditioner, a defrosting flow path mechanism is used to perform a heating defrost operation for evaporating the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger while defrosting an arbitrary heat exchange path. It has become. In this heating defrost operation, first, the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger is not allowed to flow into the refrigerant diverter by the defrost flow path mechanism, but from the gas side end of any heat exchange path. It passes through an arbitrary heat exchange path toward the side edge. Next, the refrigerant that has passed through any heat exchange path passes through the other heat exchange path from the liquid side end to the gas side end of the other heat exchange path other than the arbitrary heat exchange path through the refrigerant flow divider. Let
　この空気調和装置では、デフロスト用流路機構を用いた暖房デフロスト運転を複数の熱交パスに対して順次行うことによって、室外熱交換器全体の除霜を行うことができる。そして、この暖房デフロスト運転では、圧縮機において圧縮された冷媒の全流量を室内熱交換器に送って暖房に使用し、その後、室内熱交換器から室外熱交換器に送られる冷媒の熱によって除霜を行うことができる。これにより、暖房能力をほとんど低下させることなく、高い除霜能力を得つつ、また、外気温度が０℃以下の気象条件においても、室外熱交換器の除霜を行うことができる。 In this air conditioner, the entire outdoor heat exchanger can be defrosted by sequentially performing the heating defrost operation using the defrost flow path mechanism on the plurality of heat exchange paths. In this heating defrost operation, the entire flow rate of the refrigerant compressed in the compressor is sent to the indoor heat exchanger and used for heating, and then removed by the heat of the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger. Frost can be done. Thereby, defrosting of the outdoor heat exchanger can be performed while obtaining a high defrosting capacity without substantially reducing the heating capacity and also in a weather condition where the outside air temperature is 0 ° C. or less.
　第２の観点にかかる空気調和装置は、第１の観点にかかる空気調和装置において、室外熱交換器が、室内熱交換器から室外熱交換器に送られる冷媒が冷媒分流器に流入する前に通過する過冷却パスをさらに有している。そして、デフロスト用流路機構は、室内熱交換器から室外熱交換器に送られる冷媒を、過冷却パスを通過させた後に、複数の熱交パスのうち任意に選択された熱交パスのガス側端に送ることができるように設けられている。
　この空気調和装置では、暖房デフロスト運転中にも過冷却パスに冷媒を通過させることができるため、熱交パスの除霜によって発生したドレン水の再凍結を防止して、室外熱交換器の下部から速やかに排水することができる。 An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the outdoor heat exchanger before the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger flows into the refrigerant distributor. It further has a subcooling path through. Then, the defrosting flow path mechanism allows the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to pass through the supercooling path, and then the gas in the heat exchange path arbitrarily selected from the plurality of heat exchange paths. It is provided so that it can be sent to the side end.
In this air conditioner, since the refrigerant can pass through the supercooling path even during the heating defrost operation, it is possible to prevent the re-freezing of the drain water generated by the defrosting of the heat exchange path, and the lower part of the outdoor heat exchanger. Can be drained quickly.
　第３の観点にかかる空気調和装置は、第１の観点にかかる空気調和装置において、室外熱交換器が、室内熱交換器から室外熱交換器に送られる冷媒が冷媒分流器に流入する前に通過する過冷却パスをさらに有している。そして、デフロスト用流路機構は、室内熱交換器から室外熱交換器に送られる冷媒を、過冷却パスを通過させることなく、複数の熱交パスのうち任意に選択された熱交パスのガス側端に送ることができるように設けられている。
　この空気調和装置では、暖房デフロスト運転中に過冷却パスに冷媒を通過させることなく、熱交パスの除霜を行うことができるため、冷媒の熱を熱交パスの除霜だけに使用することができる。 An air conditioner according to a third aspect is the air conditioner according to the first aspect, wherein the outdoor heat exchanger before the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger flows into the refrigerant distributor. It further has a subcooling path through. Then, the defrosting flow path mechanism is configured such that the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger passes through the subcooling path, and the gas in the heat exchange path arbitrarily selected from the plurality of heat exchange paths. It is provided so that it can be sent to the side end.
In this air conditioner, the heat exchange path can be defrosted without passing the refrigerant through the supercooling path during the heating defrost operation, so the heat of the refrigerant is used only for the defrosting of the heat exchange path. Can do.
本発明の第１実施形態にかかる空気調和装置の概略構成図である。It is a schematic structure figure of the air harmony device concerning a 1st embodiment of the present invention. 室外ユニットの平面図（天板を取り除いて図示）である。It is a top view (illustrated by removing the top plate) of the outdoor unit. 第１実施形態の室外熱交換器及びその近傍の構造を模式的に示した図である。It is the figure which showed typically the outdoor heat exchanger of 1st Embodiment, and the structure of the vicinity. 空気調和装置の制御ブロック図である。It is a control block diagram of an air conditioning apparatus. 第１実施形態の暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating operation of 1st Embodiment. 暖房デフロスト運転のフローチャートである。It is a flowchart of heating defrost operation. 第１実施形態の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 第１実施形態の暖房デフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。FIG. 3 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation of the first embodiment. 従来（特許文献２）のデフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。FIG. 6 is a pressure-enthalpy diagram illustrating a conventional refrigeration cycle during defrost operation (Patent Document 2). 第１実施形態の変形例１の暖房デフロスト運転のフローチャートである。It is a flowchart of the heating defrost driving | operation of the modification 1 of 1st Embodiment. 第１実施形態の変形例２にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 2 of 1st Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第１実施形態の変形例２の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 2 of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 第１実施形態の変形例３にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 3 of 1st Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第１実施形態の変形例３の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 3 of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 第１実施形態の変形例４にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 4 of 1st Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第１実施形態の変形例４の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 4 of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 第１実施形態の変形例５にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 5 of 1st Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第１実施形態の変形例５の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 5 of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 第１実施形態の変形例６にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 6 of 1st Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第１実施形態の変形例６の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 6 of 1st Embodiment (when defrosting a 1st heat exchange path | pass). 本発明の第２実施形態にかかる空気調和装置の概略構成図である。It is a schematic block diagram of the air conditioning apparatus concerning 2nd Embodiment of this invention. 第２実施形態の室外熱交換器及びその近傍の構造を模式的に示した図である。It is the figure which showed typically the outdoor heat exchanger of 2nd Embodiment, and the structure of the vicinity. 第２実施形態の暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating operation of 2nd Embodiment. 第２実施形態の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of 2nd Embodiment (when defrosting a 1st heat exchange path | pass). 第２実施形態の暖房デフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。FIG. 6 is a pressure-enthalpy diagram illustrating a refrigeration cycle during a heating defrost operation according to a second embodiment. 第２実施形態の変形例２にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 2 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第２実施形態の変形例２の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 2 of 2nd Embodiment (when defrosting a 1st heat exchange path | pass). 第２実施形態の変形例３にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 3 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第２実施形態の変形例３の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 3 of 2nd Embodiment (when defrosting a 1st heat exchange path | pass). 第２実施形態の変形例４にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 4 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第２実施形態の変形例４の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 4 of 2nd Embodiment (when defrosting a 1st heat exchange path | pass). 第２実施形態の変形例５にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 5 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第３実施形態の変形例５の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 5 of 3rd Embodiment (when defrosting a 1st heat exchange path | pass). 第２実施形態の変形例６にかかる空気調和装置の概略構成図であり、暖房運転時における空気調和装置内の冷媒の流れを示す図である。It is a schematic block diagram of the air conditioning apparatus concerning the modification 6 of 2nd Embodiment, and is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of heating operation. 第２実施形態の変形例６の暖房デフロスト運転時における空気調和装置内の冷媒の流れ（第１熱交パスの除霜を行う場合）を示す図である。It is a figure which shows the flow of the refrigerant | coolant in the air conditioning apparatus at the time of the heating defrost driving | operation of the modification 6 of 2nd Embodiment (when defrosting a 1st heat exchange path | pass). 本発明の他の実施形態にかかる空気調和装置の概略構成図である。It is a schematic block diagram of the air conditioning apparatus concerning other embodiment of this invention. 本発明の他の実施形態にかかる空気調和装置の概略構成図である。It is a schematic block diagram of the air conditioning apparatus concerning other embodiment of this invention.
　以下、本発明にかかる空気調和装置の実施形態について、図面に基づいて説明する。
　＜第１実施形態＞
　（全体構成）
　図１は、本発明の第１実施形態にかかる空気調和装置１の概略構成図である。空気調和装置１は、暖房運転を行うことが可能であり、ここでは、スプリットタイプのものが採用されている。空気調和装置１は、主として、室外ユニット２と、室内ユニット４と、室外ユニット２と室内ユニット４とを接続する液冷媒連絡管５及びガス冷媒連絡管６とを有している。そして、室外ユニット２と室内ユニット４とは、液冷媒連絡管５及びガス冷媒連絡管６を介して接続されることによって蒸気圧縮式の冷凍サイクルを行うための冷媒回路１０を構成している。 DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an air conditioner according to the present invention will be described with reference to the drawings.
<First Embodiment>
(overall structure)
FIG. 1 is a schematic configuration diagram of an air-conditioning apparatus 1 according to the first embodiment of the present invention. The air conditioner 1 can perform a heating operation, and a split type is adopted here. The air conditioner 1 mainly includes an outdoor unit 2, an indoor unit 4, and a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6 that connect the outdoor unit 2 and the indoor unit 4. The outdoor unit 2 and the indoor unit 4 constitute a refrigerant circuit 10 for performing a vapor compression refrigeration cycle by being connected via a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6.
　（室内ユニット）
　室内ユニット４は、室内に設置されており、冷媒回路１０の一部を構成している。室内ユニット４は、主として、室内熱交換器４１を有している。
　室内熱交換器４１は、冷房運転時には冷媒の蒸発器として機能して室内空気を冷却し、暖房運転時には冷媒の放熱器として機能して室内空気を加熱する熱交換器である。ここでは、室内熱交換器４１として、伝熱管と多数のフィンとにより構成されたクロスフィン式のフィン・アンド・チューブ型熱交換器が採用されている。室内熱交換器４１は、その液側が液冷媒連絡管５に接続されており、ガス側がガス冷媒連絡管６に接続されている。
　また、室内ユニット４は、室内ユニット４を構成する各部の動作を制御する室内制御部４９を有している。そして、室内制御部４１は、室内ユニット４の制御を行うためのマイクロコンピュータやメモリ等を有しており、室外ユニット２の室外制御部２９（後述）との間で制御信号等のやりとりを行うことができるようになっている。 (Indoor unit)
The indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 10. The indoor unit 4 mainly has an indoor heat exchanger 41.
The indoor heat exchanger 41 is a heat exchanger that functions as a refrigerant evaporator during cooling operation to cool indoor air, and functions as a refrigerant radiator during heating operation to heat indoor air. Here, as the indoor heat exchanger 41, a cross fin type fin-and-tube heat exchanger constituted by heat transfer tubes and a large number of fins is employed. The indoor heat exchanger 41 has a liquid side connected to the liquid refrigerant communication tube 5 and a gas side connected to the gas refrigerant communication tube 6.
The indoor unit 4 has an indoor control unit 49 that controls the operation of each unit constituting the indoor unit 4. The indoor control unit 41 includes a microcomputer and a memory for controlling the indoor unit 4, and exchanges control signals and the like with the outdoor control unit 29 (described later) of the outdoor unit 2. Be able to.
　（室外ユニット）
　室外ユニット２は、室外に設置されており、冷媒回路１０の一部を構成している。室外ユニット２は、主として、圧縮機２１と、四路切換弁２２と、室外熱交換器２３と、膨張弁２４と、室外ファン２５と、デフロスト用流路機構２６とを有している。ここでは、図２に示すように、室外ユニット２として、略直方体箱状のユニットケーシング５１の内部が鉛直に延びる仕切板５８により送風機室Ｓ１と機械室Ｓ２とに分割された構造（いわゆる、トランク型構造）が採用されている。ここで、図２は、室外ユニット２の平面図（天板を取り除いて図示）である。そして、室外ユニット２は、主として、略矩形箱状のユニットケーシング５１内に各種機器２１～２６等が収容されている。
　ユニットケーシング５１は、主として、底板５２と、天板と、左前板５４と、右前板５６と、右側板５７と、仕切板５８とを有している。底板５２は、ユニットケーシング５１の底面部分を構成する横長の略長方形状の板状部材である。底板５２は、室外熱交換器２３から流下するドレン水を受けるためのドレンパンとしても機能するようになっている。天板は、図２には図示しないが、室外ユニット２の天面部分を構成する横長の略長方形状の板状部材である。左前板５４は、主として、ユニットケーシング５１の左前面部分及び左側面部分を構成する板状部材である。左前板５４には、室外ファン２５によってユニットケーシング５１内に吸入される空気の吸入口５５ａが形成されている。また、左前板５４には、室外ファン２５によってユニットケーシング５１の背面側及び左側面側から内部に取り込まれた空気を外部に吹き出すための吹出口５４ａが設けられている。右前板５６は、主として、ユニットケーシング５１の右前面部分及び右側面の前部を構成する板状部材である。右側板５７は、主として、ユニットケーシング５１の右側面の後部及び右背面部分を構成する板状部材である。そして、左前板５４の後端部と右側板５７の背面側端部と左右方向間には、室外ファン３２によってユニットケーシング５１内に吸入される空気の吸入口５５ｂが形成されている。仕切板５８は、底板５２上に配置される鉛直に延びる板状部材であり、ユニットケーシング５１の内部空間を左右２つの空間（すなわち、送風機室Ｓ１及び機械室Ｓ２）に仕切るように配置されている。 (Outdoor unit)
The outdoor unit 2 is installed outside and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an expansion valve 24, an outdoor fan 25, and a defrost flow path mechanism 26. Here, as shown in FIG. 2, the outdoor unit 2 has a structure in which the inside of a substantially rectangular parallelepiped box-shaped unit casing 51 is divided into a blower chamber S <b> 1 and a machine chamber S <b> 2 by a partition plate 58 extending vertically (so-called trunk Mold structure) is adopted. Here, FIG. 2 is a plan view of the outdoor unit 2 (illustrated with the top plate removed). In the outdoor unit 2, various devices 21 to 26 and the like are accommodated mainly in a unit casing 51 having a substantially rectangular box shape.
The unit casing 51 mainly includes a bottom plate 52, a top plate, a left front plate 54, a right front plate 56, a right side plate 57, and a partition plate 58. The bottom plate 52 is a horizontally long and substantially rectangular plate-like member that constitutes the bottom surface portion of the unit casing 51. The bottom plate 52 functions as a drain pan for receiving drain water flowing down from the outdoor heat exchanger 23. Although not shown in FIG. 2, the top plate is a horizontally long and substantially rectangular plate-like member that constitutes the top surface portion of the outdoor unit 2. The left front plate 54 is a plate-like member mainly constituting the left front surface portion and the left side surface portion of the unit casing 51. The left front plate 54 is formed with a suction port 55a for air sucked into the unit casing 51 by the outdoor fan 25. Further, the left front plate 54 is provided with an outlet 54a for blowing out air taken in from the back side and the left side of the unit casing 51 by the outdoor fan 25 to the outside. The right front plate 56 is a plate-like member that mainly constitutes the front portion of the right front surface and the right side surface of the unit casing 51. The right side plate 57 is a plate-like member that mainly constitutes the rear portion and the right back portion of the right side surface of the unit casing 51. Between the rear end portion of the left front plate 54 and the rear side end portion of the right side plate 57 and the left and right direction, an air inlet 55b that is sucked into the unit casing 51 by the outdoor fan 32 is formed. The partition plate 58 is a vertically extending plate-like member disposed on the bottom plate 52, and is disposed so as to partition the internal space of the unit casing 51 into two left and right spaces (that is, the fan chamber S1 and the machine chamber S2). Yes.
　圧縮機２１は、冷凍サイクルにおける低圧のガス冷媒を吸入し、圧縮して冷凍サイクルにおける高圧のガス冷媒とした後に吐出するための圧縮機である。ここでは、圧縮機２１として、ケーシング（図示せず）内に収容されたロータリ式やスクロール式等の容積式の圧縮要素（図示せず）が、同じくケーシング内に収容された圧縮機モータ２１ａによって駆動される密閉式圧縮機が採用されている。圧縮機２１は、その吸入側及び吐出側が四路切換弁２２に接続されている。尚、圧縮機２１は、機械室Ｓ２内に配置されている。
　四路切換弁２２は、冷房運転と暖房運転との切換時に、冷媒の流れの方向を切り換えるための弁である。四路切換弁２２は、冷房運転時には、圧縮機２１の吐出側と室外熱交換器２３のガス側とを接続するとともにガス冷媒連絡管６と圧縮機２１の吸入側とを接続することが可能である（図１における四路切換弁２２の実線を参照）。また、四路切換弁２２は、暖房運転時には、圧縮機２１の吐出側とガス冷媒連絡管６とを接続するとともに室外熱交換器２３のガス側と圧縮機２１の吸入側とを接続することが可能である（図１における四路切換弁２２の破線を参照）。四路切換弁２２は、ガス冷媒連絡管６と、圧縮機２１の吸入側及び吐出側と、室外熱交換器２３のガス側とに接続されている。尚、四路切換弁２２は、図２には図示しないが、機械室Ｓ２内に配置されている。 The compressor 21 is a compressor for sucking and compressing a low-pressure gas refrigerant in the refrigeration cycle to form a high-pressure gas refrigerant in the refrigeration cycle. Here, as the compressor 21, a volumetric compression element (not shown) such as a rotary type or a scroll type accommodated in a casing (not shown) is used by a compressor motor 21a also accommodated in the casing. A driven hermetic compressor is employed. The suction side and the discharge side of the compressor 21 are connected to the four-way switching valve 22. The compressor 21 is disposed in the machine room S2.
The four-way switching valve 22 is a valve for switching the direction of the refrigerant flow when switching between the cooling operation and the heating operation. The four-way switching valve 22 can connect the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 and can connect the gas refrigerant communication pipe 6 and the suction side of the compressor 21 during cooling operation. (Refer to the solid line of the four-way switching valve 22 in FIG. 1). The four-way switching valve 22 connects the discharge side of the compressor 21 and the gas refrigerant communication pipe 6 and connects the gas side of the outdoor heat exchanger 23 and the suction side of the compressor 21 during heating operation. (Refer to the broken line of the four-way switching valve 22 in FIG. 1). The four-way switching valve 22 is connected to the gas refrigerant communication pipe 6, the suction side and discharge side of the compressor 21, and the gas side of the outdoor heat exchanger 23. Although not shown in FIG. 2, the four-way switching valve 22 is disposed in the machine room S2.
　室外熱交換器２３は、冷房運転時には冷媒の放熱器として機能し、暖房運転時には冷媒の蒸発器として機能する熱交換器である。ここでは、室外熱交換器２３として、伝熱管と多数のフィンとにより構成されたクロスフィン式のフィン・アンド・チューブ型熱交換器が採用されている。室外熱交換器２３は、その液側が液冷媒管２７を介して膨張弁２４に接続されており、ガス側がガス冷媒管２８を介して四路切換弁２２に接続されている。
　より具体的には、室外熱交換器２３は、多数のフィン６１と、これらのフィン６１を板厚方向に貫通させた状態で取り付けられた多数の伝熱管６２とを有している（図２を参照）。この室外熱交換器２３においては、図３に示すように、伝熱管６１を上下方向に複数（ここでは、３つ）の系統に分けて、これらを相互に独立した第１熱交パス３１、第２熱交パス３２、及び、第３熱交パス３３としている。ここで、図３は、室外熱交換器２３及びその近傍の構造を模式的に示した図である。そして、第１～第３熱交パス３１～３３の液側端は、それぞれ第１～第３キャピラリチューブ６３ａ～６３ｃを介して冷媒分流器６４に接続されている。冷媒分流器６４は、第１～第３熱交パス３１～３３の液側端に接続された第１～第３キャピラリチューブ６３ａ～６３ｃを合流させる管部材であり、液冷媒管２７に接続されている。第１～第３熱交パス３１～３３のガス側端は、それぞれ第１～第３ヘッダー連絡管６５ａ～６５ｃを介してヘッダー６６に接続されている。ヘッダー６６は、第１～第３熱交パス３１～３３のガス側端に接続された第１～第３ヘッダー連絡管６５ａ～６５ｃを合流させる管部材であり、ガス冷媒管２８に接続されている。このように、室外熱交換器２３を構成する複数（ここでは、３つ）の熱交パス３１～３３は、冷媒分流器６４及びヘッダー６６を介して互いに並列に接続されている。そして、冷房運転時には、すべての熱交パス３１～３３が冷媒の放熱器として機能し、暖房運転時には、すべての熱交パス３１～３３が冷媒の蒸発器として機能するようになっている。尚、室外熱交換器２３（すなわち、熱交パス３１～３３）は、ユニットケーシング５１の左側面から背面に沿うＬ字形状をなしている。また、熱交パス３１～３３間を接続する管部材６３ａ～６３ｃ、６４、６５ａ～６５ｃ、６６は、図２には図示しないが、室外熱交換器２３の右端側の空間、すなわち、機械室Ｓ２内に配置されている。 The outdoor heat exchanger 23 is a heat exchanger that functions as a refrigerant radiator during cooling operation and functions as a refrigerant evaporator during heating operation. Here, as the outdoor heat exchanger 23, a cross fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins is employed. The outdoor heat exchanger 23 has a liquid side connected to the expansion valve 24 via a liquid refrigerant pipe 27, and a gas side connected to the four-way switching valve 22 via a gas refrigerant pipe 28.
More specifically, the outdoor heat exchanger 23 includes a large number of fins 61 and a large number of heat transfer tubes 62 attached in a state where these fins 61 are penetrated in the plate thickness direction (FIG. 2). See). In this outdoor heat exchanger 23, as shown in FIG. 3, the heat transfer tubes 61 are divided into a plurality of (here, three) systems in the vertical direction, and these are separated from each other by a first heat exchange path 31, The second heat exchange path 32 and the third heat exchange path 33 are provided. Here, FIG. 3 is the figure which showed typically the structure of the outdoor heat exchanger 23 and its vicinity. The liquid side ends of the first to third heat exchange paths 31 to 33 are connected to the refrigerant distributor 64 via the first to third capillary tubes 63a to 63c, respectively. The refrigerant flow divider 64 is a pipe member that joins the first to third capillary tubes 63 a to 63 c connected to the liquid side ends of the first to third heat exchange paths 31 to 33, and is connected to the liquid refrigerant pipe 27. ing. The gas side ends of the first to third heat exchange paths 31 to 33 are connected to the header 66 via first to third header communication pipes 65a to 65c, respectively. The header 66 is a pipe member that joins the first to third header connecting pipes 65a to 65c connected to the gas side ends of the first to third heat exchange paths 31 to 33, and is connected to the gas refrigerant pipe 28. Yes. As described above, the plurality of (here, three) heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 are connected in parallel to each other via the refrigerant flow divider 64 and the header 66. During the cooling operation, all the heat exchange paths 31 to 33 function as a refrigerant radiator, and during the heating operation, all the heat exchange paths 31 to 33 function as a refrigerant evaporator. The outdoor heat exchanger 23 (that is, the heat exchange paths 31 to 33) has an L shape extending from the left side surface of the unit casing 51 to the back surface. Further, the pipe members 63a to 63c, 64, 65a to 65c, 66 for connecting the heat exchange paths 31 to 33 are not shown in FIG. 2, but the right end space of the outdoor heat exchanger 23, that is, the machine room. Arranged in S2.
　膨張弁２４は、冷房運転時には室外熱交換器２３において放熱した高圧の液冷媒を室内熱交換器４１に送る前に減圧し、暖房運転時には室内熱交換器４１において放熱した高圧の液冷媒を室外熱交換器２３に送る前に減圧することが可能な電動膨張弁である。膨張弁２４は、液冷媒管２７に設けられており、その一端が液冷媒連絡管５に接続されており、他端が室外熱交換器２３に接続されている。尚、膨張弁２４は、図２には図示しないが、機械室Ｓ２内に配置されている。
　室外ファン２５は、室外ユニット２内に室外空気を吸入して、室外熱交換器２３に室外空気を供給した後に、ユニット外に排出するための送風機である。ここでは、室外ファン２５として、室外ファンモータ２５ａによって駆動されるプロペラファンが採用されている。尚、室外ファン２５は、送風機室Ｓ１内の室外熱交換器２３の前側に配置されている。室外ファン２３を駆動すると、ユニットケーシング５１の背面及び左側面の吸入口５５ａ、５５ｂを通じて、内部に空気が取り込まれて、室外熱交換器２３を通過した後、ユニットケーシング５１の前面の吹出口５４ａからユニットケーシング５１の外部へ空気が吹き出されるようになっている。これにより、室外熱交換器２３は、室外空気を冷却源として冷媒の放熱を行い、又は、室外空気を加熱源として冷媒を蒸発させる熱交換器となっている。 The expansion valve 24 depressurizes the high-pressure liquid refrigerant radiated in the outdoor heat exchanger 23 during the cooling operation before sending it to the indoor heat exchanger 41, and the high-pressure liquid refrigerant radiated in the indoor heat exchanger 41 during the heating operation. This is an electric expansion valve that can be decompressed before being sent to the heat exchanger 23. The expansion valve 24 is provided in the liquid refrigerant pipe 27, one end of which is connected to the liquid refrigerant communication pipe 5, and the other end is connected to the outdoor heat exchanger 23. Although not shown in FIG. 2, the expansion valve 24 is disposed in the machine room S2.
The outdoor fan 25 is a blower for sucking outdoor air into the outdoor unit 2, supplying the outdoor air to the outdoor heat exchanger 23, and then discharging the air outside the unit. Here, as the outdoor fan 25, a propeller fan driven by an outdoor fan motor 25a is employed. The outdoor fan 25 is disposed on the front side of the outdoor heat exchanger 23 in the blower chamber S1. When the outdoor fan 23 is driven, air is taken into the interior through the suction ports 55a and 55b on the back surface and the left side surface of the unit casing 51, and after passing through the outdoor heat exchanger 23, the air outlet 54a on the front surface of the unit casing 51. The air is blown out from the unit casing 51 to the outside. Thus, the outdoor heat exchanger 23 is a heat exchanger that radiates the refrigerant using outdoor air as a cooling source or evaporates the refrigerant using outdoor air as a heating source.
　デフロスト用流路機構２６は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送るための機構である。このデフロスト用流路機構２６は、後述の暖房デフロスト運転を行うために設けられている。この暖房デフロスト運転は、室外熱交換器２３を構成する熱交パス３１～３３のうちの任意の熱交パスの除霜を行いつつ、室内熱交換器４１から室外熱交換器２３に送られる冷媒を蒸発させる運転である。デフロスト用流路機構２６は、主として、熱交パス供給管７１と、複数（ここでは、３つ）の熱交パス分岐管７２ａ～７２ｃと、複数（ここでは、３つ）の分岐管側熱交パス選択弁７３ａ～７３ｃと、複数（ここでは、３つ）のヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とを有している。尚、デフロスト流路機構２６（すなわち、冷媒管及び弁７１、７２ａ～７２ｃ、７３ａ～７３ｃ、７４ａ～７４ｃ、７５）は、図２には図示しないが、機械室Ｓ２内に配置されている。 The defrosting flow path mechanism 26 is arbitrarily selected from the plurality of heat exchange paths 31 to 33 without causing the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 to flow into the refrigerant flow divider 64. It is a mechanism for sending to the gas side end of the heat exchange path. The defrost flow path mechanism 26 is provided to perform a heating defrost operation which will be described later. In this heating defrost operation, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 while defrosting any heat exchange path among the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23. It is the operation which evaporates. The defrost flow path mechanism 26 mainly includes a heat exchange path supply pipe 71, a plurality (here, three) of heat exchange path branch pipes 72a to 72c, and a plurality (here, three) of branch pipe side heat. There are exchange path selection valves 73a to 73c, a plurality (three in this case) of header side heat exchange path selection valves 74a to 74c, and a branch pipe side selection valve 75. The defrost channel mechanism 26 (that is, the refrigerant pipes and valves 71, 72a to 72c, 73a to 73c, 74a to 74c, 75) is disposed in the machine room S2, although not shown in FIG.
　熱交パス供給管７１は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を冷媒分流器６４に流入させる前に液冷媒管２７から分岐するための冷媒管である。熱交パス供給管７１は、その一端が液冷媒管２７のうち膨張弁２４と冷媒分流器６４との間の部分に接続されており、他端が熱交パス分岐管７２ａ～７２ｃに接続されている。
　第１～第３熱交パス分岐管７２ａ～７２ｃは、熱交パス供給管７１を流れる冷媒を第１～第３熱交パス３１～３３のガス側端に供給するための冷媒管である。第１～第３熱交パス分岐管７２ａ～７２ｃは、それぞれ、その一端が熱交パス供給管７１に接続されており、他端が第１～第３ヘッダー連絡管６５ａ～６５ｃに接続されている。
　第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃは、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃとともに、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のいずれの熱交パスのガス側端に冷媒を送るかを選択するための電磁弁である。第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃは、それぞれ第１～第３熱交パス分岐管７２ａ～７２ｃに設けられている。そして、冷房運転時及び暖房運転時には、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止されるようになっている。また、暖房デフロスト運転時には、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃのうち除霜を行う熱交パスに対応する分岐管側熱交パス選択弁が開けられ、それ以外の熱交パスに対応する分岐管側熱交パス選択弁が閉止されるようになっている。 The heat exchange path supply pipe 71 is a refrigerant pipe for branching from the liquid refrigerant pipe 27 before the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 flows into the refrigerant flow divider 64. One end of the heat exchange path supply pipe 71 is connected to a portion of the liquid refrigerant pipe 27 between the expansion valve 24 and the refrigerant distributor 64, and the other end is connected to the heat exchange path branch pipes 72a to 72c. ing.
The first to third heat exchange path branch pipes 72a to 72c are refrigerant pipes for supplying the refrigerant flowing through the heat exchange path supply pipe 71 to the gas side ends of the first to third heat exchange paths 31 to 33. Each of the first to third heat exchange path branch pipes 72a to 72c has one end connected to the heat exchange path supply pipe 71 and the other end connected to the first to third header communication pipes 65a to 65c. Yes.
The first to third branch pipe side heat exchange path selection valves 73a to 73c, together with the first to third header side heat exchange path selection valves 74a to 74c, allow the refrigerant flowing through the heat exchange path supply pipe 71 to pass through the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to. The first to third branch pipe side heat exchange path selection valves 73a to 73c are provided in the first to third heat exchange path branch pipes 72a to 72c, respectively. During the cooling operation and the heating operation, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed. Further, during the heating defrost operation, the branch pipe side heat exchange path selection valve corresponding to the heat exchange path for defrosting among the first to third branch pipe side heat exchange path selection valves 73a to 73c is opened. The branch pipe side heat exchange path selection valve corresponding to the heat exchange path is closed.
　第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃは、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃとともに、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のいずれの熱交パスのガス側端に冷媒を送るかを選択するための電磁弁である。第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃは、それぞれ第１～第３ヘッダー連絡管６５ａ～６５ｃのうち第１～第３熱交パス分岐管７２ａ～７２ｃの他端が接続された位置とヘッダー６６との間の部分に設けられている。そして、冷房運転時及び暖房運転時には、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられるようになっている。また、暖房デフロスト運転時には、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃのうち除霜を行う熱交パスに対応するヘッダー側熱交パス選択弁が閉止され、それ以外の熱交パスに対応するヘッダー側熱交パス選択弁が開けられるようになっている。 The first to third header side heat exchange path selection valves 74a to 74c, together with the first to third branch pipe side heat exchange path selection valves 73a to 73c, transfer the refrigerant flowing through the heat exchange path supply pipe 71 to the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to. The first to third header side heat exchange path selection valves 74a to 74c are connected to the other ends of the first to third heat exchange path branch pipes 72a to 72c among the first to third header communication pipes 65a to 65c, respectively. It is provided in a portion between the position and the header 66. During the cooling operation and the heating operation, all of the first to third header side heat exchange path selection valves 74a to 74c are opened. In addition, during the heating defrost operation, the header side heat exchange path selection valve corresponding to the heat exchange path for defrosting is closed among the first to third header side heat exchange path selection valves 74a to 74c, and the other heat exchanges are performed. The header side heat exchange path selection valve corresponding to the path can be opened.
　分流管側選択弁７５は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を分流器６４に流入させる前に液冷媒管２７から分岐するかどうかを選択するための電磁弁である。分流管側選択弁７５は、液冷媒管２７のうち熱交パス供給管７１が分岐された位置と冷媒分流器６４との間の部分に設けられている。そして、冷房運転時及び暖房運転時には、分流管側選択弁７５が開けられるようになっている。また、暖房デフロスト運転時には、分流管側選択弁７５が閉止されるようになっている。
　また、室外ユニット２には、室外熱交換器２３を流れる冷媒の飽和温度Ｔｓａｔを検出する室外熱交温度センサ６７が設けられている。ここでは、室外熱交温度センサ６７は、室外熱交換器２３の第１熱交パス３１の液側端の近傍に設けられている。
　また、室外ユニット２は、室外ユニット２を構成する各部の動作を制御する室外制御部２９を有している。そして、室外制御部２９は、室外ユニット２の制御を行うためのマイクロコンピュータやメモリ等を有しており、室内ユニット４の室内制御部４９との間で制御信号等のやりとりを行うことができるようになっている。 The branch pipe side selection valve 75 is an electromagnetic valve for selecting whether the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is branched from the liquid refrigerant pipe 27 before flowing into the flow divider 64. . The branch pipe side selection valve 75 is provided in a portion between the position where the heat exchange path supply pipe 71 is branched in the liquid refrigerant pipe 27 and the refrigerant flow divider 64. And the shunt pipe side selection valve 75 is opened at the time of air_conditionaing | cooling operation and heating operation. Further, during the heating defrost operation, the branch pipe side selection valve 75 is closed.
The outdoor unit 2 is provided with an outdoor heat exchange temperature sensor 67 that detects a saturation temperature Tsat of the refrigerant flowing through the outdoor heat exchanger 23. Here, the outdoor heat exchange temperature sensor 67 is provided in the vicinity of the liquid side end of the first heat exchange path 31 of the outdoor heat exchanger 23.
The outdoor unit 2 also has an outdoor control unit 29 that controls the operation of each part constituting the outdoor unit 2. The outdoor control unit 29 includes a microcomputer and a memory for controlling the outdoor unit 2, and can exchange control signals and the like with the indoor control unit 49 of the indoor unit 4. It is like that.
　そして、室外制御部２９と室内制御部４９とによって、空気調和装置１の運転制御等を行う制御部８が構成されている（図１及び図４を参照）。ここで、図４は、空気調和装置１の制御ブロック図である。
　（動作）
　次に、上記の構成を有する空気調和装置１の動作について説明する。尚、以下の動作を行うために必要な各種機器の制御や各種処理等は、制御部８によって行われる。
　空気調和装置１の運転としては、室内の冷房を行う冷房運転と、室内の暖房のみを行う暖房運転と、室外熱交換器２３の除霜を行いつつ室内の暖房を行う暖房デフロスト運転とがある。以下、各運転時の動作について、図５～図８を用いて説明する。ここで、図５は、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図６は、暖房デフロスト運転のフローチャートである。図７は、暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。図８は、暖房デフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。 And the outdoor control part 29 and the indoor control part 49 comprise the control part 8 which performs operation control etc. of the air conditioning apparatus 1 (refer FIG.1 and FIG.4). Here, FIG. 4 is a control block diagram of the air conditioner 1.
(Operation)
Next, operation | movement of the air conditioning apparatus 1 which has said structure is demonstrated. Note that the control unit 8 performs control of various devices and various processes necessary for performing the following operations.
The operation of the air conditioner 1 includes a cooling operation that cools the room, a heating operation that only heats the room, and a heating defrost operation that heats the room while defrosting the outdoor heat exchanger 23. . Hereinafter, the operation during each operation will be described with reference to FIGS. Here, FIG. 5 is a diagram illustrating the flow of the refrigerant in the air conditioner 1 during the heating operation. FIG. 6 is a flowchart of the heating defrost operation. FIG. 7 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating and defrosting operation (when defrosting the first heat exchange path 31). FIG. 8 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation.
　－冷房運転－
　冷房運転は、圧縮機２１、室外熱交換器２３、室内熱交換器４１、圧縮機２１の順に冷媒を循環させる運転である。この冷房運転では、室外熱交換器２３が冷媒の放熱器として機能し、かつ、室内熱交換器４１が冷媒の蒸発器として機能し、これにより、室内空気を冷却する。
　冷房運転においては、室外熱交換器２３が冷媒の放熱器として機能し、かつ、室内熱交換器４１が冷媒の蒸発器として機能する状態（すなわち、図１の四路切換弁２２の実線で示される状態）になるように、四路切換弁２２が切り換えられる。また、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止され、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられ、分流管側選択弁７５が開けられた状態になっている。すなわち、デフロスト用流路機構２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃには、冷媒が流れない状態になっている。 -Cooling operation-
The cooling operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the outdoor heat exchanger 23, the indoor heat exchanger 41, and the compressor 21. In this cooling operation, the outdoor heat exchanger 23 functions as a refrigerant radiator, and the indoor heat exchanger 41 functions as a refrigerant evaporator, thereby cooling indoor air.
In the cooling operation, the outdoor heat exchanger 23 functions as a refrigerant radiator and the indoor heat exchanger 41 functions as a refrigerant evaporator (that is, indicated by the solid line of the four-way switching valve 22 in FIG. 1). The four-way selector valve 22 is switched so that Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26.
　このような状態の冷媒回路１０において、冷凍サイクルにおける低圧の冷媒は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、室外熱交換器２３に送られる。そして、圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２、ガス冷媒管２８、ヘッダー６６、ヘッダー連絡管６５ａ～６５ｃ、及び、ヘッダー側熱交パス選択弁７４ａ～７４ｃを通じて、室外熱交換器２３の熱交パス３１～３３のガス側端に送られる。そして、熱交パス３１～３３のガス側端に送られた高圧の冷媒は、熱交パス３１～３３において、室外ファン２５によって供給される室外空気と熱交換を行って放熱する。そして、熱交パス３１～３３において放熱した高圧の冷媒は、熱交パス３１～３３の液側端から、キャピラリチューブ６３ａ～６３ｃ、冷媒分流器６４、液冷媒管２７、及び、分流管側選択弁７５を通じて、膨張弁２４に送られる。膨張弁２４に送られた冷媒は、冷凍サイクルにおける低圧まで減圧される。膨張弁２４において減圧された低圧の冷媒は、液冷媒連絡管５を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた低圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って蒸発する。室内熱交換器４１において蒸発した低圧の冷媒は、ガス冷媒連絡管６及び四路切換弁２２を通じて、再び、圧縮機２１に吸入される。 In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 through the four-way switching valve 22. The high-pressure refrigerant discharged from the compressor 21 passes through the four-way switching valve 22, the gas refrigerant pipe 28, the header 66, the header communication pipes 65a to 65c, and the header side heat exchange path selection valves 74a to 74c. It is sent to the gas side ends of the heat exchange paths 31 to 33 of the heat exchanger 23. Then, the high-pressure refrigerant sent to the gas side ends of the heat exchange paths 31 to 33 performs heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33 to radiate heat. Then, the high-pressure refrigerant radiated in the heat exchange paths 31 to 33 is selected from the liquid side ends of the heat exchange paths 31 to 33 from the capillary tubes 63a to 63c, the refrigerant flow divider 64, the liquid refrigerant pipe 27, and the branch pipe side selection. It is sent to the expansion valve 24 through the valve 75. The refrigerant sent to the expansion valve 24 is depressurized to a low pressure in the refrigeration cycle. The low-pressure refrigerant decompressed by the expansion valve 24 is sent to the indoor heat exchanger 41 through the liquid refrigerant communication pipe 5. The low-pressure refrigerant sent to the indoor heat exchanger 41 evaporates by exchanging heat with indoor air in the indoor heat exchanger 41. The low-pressure refrigerant evaporated in the indoor heat exchanger 41 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6 and the four-way switching valve 22.
　－暖房運転－
　暖房運転は、圧縮機２１、室内熱交換器４１、室外熱交換器２３、圧縮機２１の順に冷媒を循環させる運転である。この暖房運転では、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器２３が冷媒の蒸発器として機能し、これにより、室内空気を加熱する。
　暖房運転においては、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器２３が冷媒の蒸発器として機能する状態（すなわち、図１及び図５の四路切換弁２２の破線で示される状態）になるように、四路切換弁２２が切り換えられる。また、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止され、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられ、分流管側選択弁７５が開けられた状態になっている。すなわち、デフロスト用流路機構２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃには、冷媒が流れない状態になっている。 -Heating operation-
The heating operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21. In this heating operation, the indoor heat exchanger 41 functions as a refrigerant radiator, and the outdoor heat exchanger 23 functions as a refrigerant evaporator, thereby heating indoor air.
In the heating operation, the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 23 functions as a refrigerant evaporator (that is, the four-way switching valve 22 in FIGS. 1 and 5). The four-way switching valve 22 is switched so as to be in a state indicated by a broken line. Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26.
　このような状態の冷媒回路１０において、冷凍サイクルにおける低圧の冷媒は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、ガス冷媒連絡管６を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた高圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って放熱する。室内熱交換器４１において放熱した高圧の冷媒は、液冷媒連絡管５を通じて、膨張弁２４に送られて、冷凍サイクルにおける低圧まで減圧される。膨張弁２４において減圧された低圧の冷媒は、室外熱交換器２３に送られる。そして、膨張弁２４において減圧された低圧の冷媒は、液冷媒管２７、分流管側選択弁７５、冷媒分流器６４、及び、キャピラリチューブ６３ａ～６３ｃを通じて、室外熱交換器２３の熱交パス３１～３３の液側端に送られる。そして、熱交パス３１～３３の液側端に送られた低圧の冷媒は、熱交パス３１～３３において、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、熱交パス３１～３３において蒸発した低圧の冷媒は、熱交パス３１～３３のガス側端から、ヘッダー連絡管６５ａ～６５ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。 In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle. The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22. The high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41. The high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and depressurized to a low pressure in the refrigeration cycle. The low-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 23. The low-pressure refrigerant decompressed by the expansion valve 24 passes through the liquid refrigerant pipe 27, the branch pipe side selection valve 75, the refrigerant flow divider 64, and the capillary tubes 63a to 63c, and the heat exchange path 31 of the outdoor heat exchanger 23. To the liquid side end of ~ 33. The low-pressure refrigerant sent to the liquid side ends of the heat exchange paths 31 to 33 evaporates through heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33. The low-pressure refrigerant evaporated in the heat exchange paths 31 to 33 flows from the gas side ends of the heat exchange paths 31 to 33 to the header communication pipes 65a to 65c, the header side heat exchange path selection valves 74a to 74c, the header 66, and the gas. The refrigerant is again sucked into the compressor 21 through the refrigerant pipe 28 and the four-way switching valve 22.
　－暖房デフロスト運転－
　暖房デフロスト運転は、暖房運転時と同様に、圧縮機２１、室内熱交換器４１、室外熱交換器２３、圧縮機２１の順に冷媒を循環させる運転を行いつつ、デフロスト用流路機構２６によって、室外熱交換器２３の除霜を行う運転である。この暖房デフロスト運転では、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器２３の第１～第３熱交パス３１～３３のうちのいずれか１つが冷媒の放熱器として機能し、残りの熱交パス３１～３３が冷媒の蒸発器として機能する。これにより、室外熱交換器２３の第１～第３熱交パス３１～３３の除霜を順次行いつつ、室内空気を加熱する。
　暖房デフロスト運転における四路切換弁２２の切り換え状態は、暖房運転時と同様である。すなわち、四路切換弁２２は、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器２３が冷媒の蒸発器として機能する状態（すなわち、図１及び図７の四路切換弁２２の破線で示される状態）になっている。また、室外熱交換器２３の第１～第３熱交パス３１～３３の除霜を順次行うために、選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５が、冷房運転時及び暖房運転時と異なる開閉状態に切り換えられる。すなわち、暖房デフロスト運転においては、デフロスト用流路機構２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃに、冷媒が流れる状態となる。以下、暖房デフロスト運転時の動作について、暖房デフロスト運転の開始から終了までの手順も含めて、詳細に説明する。 -Heating defrost operation-
As in the heating operation, the heating defrost operation is performed by circulating the refrigerant in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21. In this operation, the outdoor heat exchanger 23 is defrosted. In this heating defrost operation, the indoor heat exchanger 41 functions as a refrigerant radiator, and any one of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 is a refrigerant radiator. The remaining heat exchange paths 31 to 33 function as a refrigerant evaporator. As a result, the indoor air is heated while the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 are sequentially defrosted.
The switching state of the four-way switching valve 22 in the heating defrost operation is the same as in the heating operation. That is, the four-way switching valve 22 is in a state in which the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 23 functions as a refrigerant evaporator (that is, the four-way valves in FIGS. 1 and 7). The state shown by the broken line of the switching valve 22). Further, since the defrosting of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 is sequentially performed, the selection valves 73a to 73c, 74a to 74c, and 75 are different from those during the cooling operation and the heating operation. Switch to open / closed state. That is, in the heating defrost operation, the refrigerant flows through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 26. Hereinafter, the operation during the heating defrost operation will be described in detail including the procedure from the start to the end of the heating defrost operation.
　まず、ステップＳ１において、暖房運転によって室外熱交換器２３における着霜量が増加し、除霜が必要になったかどうかを判定する。この除霜が必要かどうかの判定は、暖房運転の継続時間や室外熱交換器２３の温度に基づいて行うことが考えられるが、ここでは、室外熱交温度センサ６７によって検出される飽和温度Ｔｓａｔに基づいて判定している。具体的には、飽和温度Ｔｓａｔが所定温度Ｔｍ以下になっている場合には、室外熱交換器２３の除霜が必要と判定するようにしている。そして、ステップＳ１において、室外熱交換器２３の除霜が必要であると判定された場合には、ステップＳ２の処理に移行する。
　次に、ステップＳ２～Ｓ７において、室外熱交換器２３の第１～第３熱交パス３１～３３の除霜を順次行う。尚、第１～第３熱交パス３１～３３の除霜は、基本的に任意に選択してもよいが、除霜によって発生するドレン水をユニットケーシング５１の底板５２まで排水する流れを考慮すると、室外熱交換器２３の上部から下部に向けて行うことが好ましい。このため、ここでは、第１熱交パス３１、第２熱交パス３２、第３熱交パス３３の順に除霜を行うものとする。 First, in step S1, it is determined whether the amount of frost formation in the outdoor heat exchanger 23 has increased due to the heating operation, and defrosting has become necessary. Although it is conceivable to determine whether or not this defrosting is necessary based on the duration of the heating operation or the temperature of the outdoor heat exchanger 23, here, the saturation temperature Tsat detected by the outdoor heat exchanger temperature sensor 67. Judgment based on. Specifically, when the saturation temperature Tsat is equal to or lower than the predetermined temperature Tm, it is determined that defrosting of the outdoor heat exchanger 23 is necessary. And when it determines with the defrosting of the outdoor heat exchanger 23 being required in step S1, it transfers to the process of step S2.
Next, in steps S2 to S7, the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 23 are sequentially defrosted. The defrosting of the first to third heat exchange paths 31 to 33 may basically be arbitrarily selected, but the flow of drain water generated by the defrosting to the bottom plate 52 of the unit casing 51 is considered. Then, it is preferable to carry out from the upper part of the outdoor heat exchanger 23 toward the lower part. For this reason, here, defrosting shall be performed in the order of the first heat exchange path 31, the second heat exchange path 32, and the third heat exchange path 33.
　第１熱交パス３１の除霜（ステップＳ２）は、デフロスト用流路機構２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第１分岐管側熱交パス選択弁７３ａが開けられ、第２及び第３分岐管側熱交パス選択弁７３ｂ、７３ｃが閉止され、第１ヘッダー側熱交パス選択弁７４ａが閉止され、第２及び第３ヘッダー側熱交パス選択弁７４ｂ、７４ｃが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第１熱交パス３１の除霜の開始前までは暖房運転が行われていることから、第１分岐管側熱交パス選択弁７３ａを開け、第１ヘッダー側熱交パス選択弁７４ａを閉止し、分流管側選択弁７５を閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構２６の熱交パス供給管７１及び第１熱交パス分岐管７２ａに冷媒が流れる状態となる。 The defrosting (step S2) of the first heat exchange path 31 is performed by switching the open / close states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26. Specifically, the first branch pipe side heat exchange path selection valve 73a is opened, the second and third branch pipe side heat exchange path selection valves 73b and 73c are closed, and the first header side heat exchange path selection valve 74a is closed. Is closed, the second and third header side heat exchange path selection valves 74b and 74c are opened, and the flow dividing pipe side selection valve 75 is switched to a closed state. Here, since the heating operation is performed before the defrosting of the first heat exchange path 31 is started, the first branch pipe side heat exchange path selection valve 73a is opened and the first header side heat exchange path is opened. A switching operation for closing the selection valve 74a and closing the branch pipe side selection valve 75 is performed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the first heat exchange path branch pipe 72a of the defrost flow path mechanism 26.
　このような状態の冷媒回路１０において、冷凍サイクルにおける低圧の冷媒（図７及び図８の点Ａを参照）は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される（図７及び図８の点Ｂを参照）。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、ガス冷媒連絡管６を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた高圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って放熱する（図７及び図８の点Ｃを参照）。ここまでは、暖房運転時と同様である。室内熱交換器４１において放熱した高圧の冷媒は、液冷媒連絡管５を通じて、膨張弁２４に送られて、冷凍サイクルにおける高圧と低圧との間の圧力（以下、中間圧とする）まで減圧される（図７及び図８の点Ｄを参照）。膨張弁２４において減圧された中間圧の冷媒は、室外熱交換器２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第１熱交パス分岐管７２ａ、第１分岐管側熱交パス選択弁７３ａ、及び、第１ヘッダー連絡管６５ａを通じて、室外熱交換器２３の第１熱交パス３１のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第１熱交パス３１のガス側端に送られることになる。そして、第１熱交パス３１のガス側端に送られた中間圧の冷媒は、第１熱交パス３１のガス側端から液側端に向かって第１熱交パス３１内を通過し、室外熱交換器２３の第１熱交パス３１に付着した霜を溶かす（図７及び図８の点Ｅを参照）。これにより、室外熱交換器２３の第１熱交パス３１の除霜が行われる。そして、第１熱交パス３１を通過した中間圧の冷媒は、第１熱交パス３１の液側端から、第１キャピラリチューブ６３ａを通じて、冷媒分流器６４に送られる。このとき、第１キャピラリチューブ６３ａは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧（すなわち、図７及び図８の点Ｅにおける圧力）と低圧の間の圧力まで減圧されることになる（図７及び図８の点Ｆを参照）。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第２及び第３キャピラリチューブ６３ｂ、６３ｃに分岐されて、第２及び第３熱交パス３２、３３の液側端に送られる。このとき、冷媒は、第２及び第３キャピラリチューブ６３ｂ、６３ｃを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる（図７及び図８の点Ｇを参照）。そして、第２及び第３熱交パス３２、３３の液側端に送られた低圧の冷媒は、第２及び第３熱交パス３２、３３の液側端からガス側端に向かって第２及び第３熱交パス３２、３３内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する（図７及び図８の点Ａを参照）。そして、第２及び第３熱交パス３２、３３において蒸発した低圧の冷媒は、第２及び第３熱交パス３２、３３のガス側端から、第２及び第３ヘッダー連絡管６５ｂ、６５ｃ、第２及び第３ヘッダー側熱交パス選択弁７４ｂ、７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第１熱交パス３１の除霜が開始される。そして、第１熱交パス３１の除霜は、第１熱交パス３１の除霜が完了するまで行われる（ステップＳ３）。ここでは、第１熱交パス３１の除霜時間ｔ１が、予め設定された所定時間（すなわち、第１熱交パス３１の除霜が完了したとみなすことができる時間）を経過するまで行われる。 In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle (see point A in FIGS. 7 and 8) is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle ( (See point B in FIGS. 7 and 8). The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22. The high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41 (see point C in FIGS. 7 and 8). Up to this point, it is the same as in the heating operation. The high-pressure refrigerant that has radiated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and is reduced to a pressure between the high pressure and the low pressure (hereinafter referred to as intermediate pressure) in the refrigeration cycle. (See point D in FIGS. 7 and 8). The intermediate pressure refrigerant decompressed in the expansion valve 24 is sent to the outdoor heat exchanger 23. The intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71. Then, the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the first heat exchange path branch pipe 72a, the first branch pipe side heat exchange path selection valve 73a, and the first header communication pipe 65a. It is sent to the gas side end of the first heat exchange path 31 of the heat exchanger 23. Thus, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the first heat exchange path 31 without flowing into the refrigerant flow divider 64. The intermediate-pressure refrigerant sent to the gas side end of the first heat exchange path 31 passes through the first heat exchange path 31 from the gas side end of the first heat exchange path 31 toward the liquid side end, Frost adhering to the first heat exchange path 31 of the outdoor heat exchanger 23 is melted (see point E in FIGS. 7 and 8). Thereby, defrosting of the 1st heat exchange path 31 of the outdoor heat exchanger 23 is performed. The intermediate-pressure refrigerant that has passed through the first heat exchange path 31 is sent from the liquid side end of the first heat exchange path 31 to the refrigerant flow divider 64 through the first capillary tube 63a. At this time, the first capillary tube 63a flows an intermediate-pressure refrigerant having a larger flow rate than that during the cooling operation or the heating operation. Therefore, the first capillary tube 63a has a pressure loss as compared with the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure in the refrigeration cycle (that is, the pressure at point E in FIGS. 7 and 8) and the low pressure (see point F in FIGS. 7 and 8). The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the second and third capillary tubes 63b, because the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the second and third heat exchange paths 32 and 33. At this time, the refrigerant is decompressed to a low pressure in the refrigeration cycle by passing through the second and third capillary tubes 63b and 63c (see point G in FIGS. 7 and 8). The low-pressure refrigerant sent to the liquid side ends of the second and third heat exchange paths 32, 33 is second from the liquid side ends of the second and third heat exchange paths 32, 33 toward the gas side ends. Then, it passes through the third heat exchange paths 32 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25 (see point A in FIGS. 7 and 8). The low-pressure refrigerant evaporated in the second and third heat exchange paths 32 and 33 is supplied from the gas side ends of the second and third heat exchange paths 32 and 33 to the second and third header communication pipes 65b, 65c, The air is again sucked into the compressor 21 through the second and third header side heat exchange path selection valves 74b and 74c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the first heat exchange path 31 is started while continuing the indoor heating. And defrosting of the 1st heat exchange path 31 is performed until defrosting of the 1st heat exchange path 31 is completed (step S3). Here, the defrosting time t1 of the first heat exchange path 31 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the first heat exchange path 31 can be regarded as completed) has elapsed. .
　第２熱交パス３２の除霜（ステップＳ４）は、第１熱交パス３１と同様に、デフロスト用流路機構２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第２分岐管側熱交パス選択弁７３ｂが開けられ、第１及び第３分岐管側熱交パス選択弁７３ａ、７３ｃが閉止され、第２ヘッダー側熱交パス選択弁７４ｂが閉止され、第１及び第３ヘッダー側熱交パス選択弁７４ａ、７４ｃが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第２熱交パス３２の除霜の開始前までは第１熱交パス３１の除霜が行われていることから、第２分岐管側熱交パス選択弁７３ｂを開け、第１分岐管側熱交パス選択弁７３ａを閉止し、第１ヘッダー側熱交パス選択弁７４ａを開け、第２ヘッダー側熱交パス選択弁７４ｂを閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構２６の熱交パス供給管７１及び第２熱交パス分岐管７２ｂに冷媒が流れる状態となる。 The defrosting (step S4) of the second heat exchange path 32 is performed by switching the open / closed states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26 in the same manner as the first heat exchange path 31. Done. Specifically, the second branch pipe side heat exchange path selection valve 73b is opened, the first and third branch pipe side heat exchange path selection valves 73a and 73c are closed, and the second header side heat exchange path selection valve 74b. Is closed, the first and third header side heat exchange path selection valves 74a and 74c are opened, and the branch pipe side selection valve 75 is switched to a closed state. Here, since the defrosting of the first heat exchange path 31 is performed before the start of the defrosting of the second heat exchange path 32, the second branch pipe side heat exchange path selection valve 73b is opened, A switching operation is performed in which the first branch pipe side heat exchange path selection valve 73a is closed, the first header side heat exchange path selection valve 74a is opened, and the second header side heat exchange path selection valve 74b is closed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the second heat exchange path branch pipe 72b of the defrost flow path mechanism 26.
　このような状態の冷媒回路１０において、冷凍サイクルにおける低圧の冷媒は、第１熱交パス３１の除霜時と同様に、圧縮機２１において冷凍サイクルにおける高圧まで圧縮され、室内熱交換器４１において室内空気と熱交換を行って放熱し、膨張弁２４において冷凍サイクルにおける中間圧まで減圧され、室外熱交換器２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第２熱交パス分岐管７２ｂ、第２分岐管側熱交パス選択弁７３ｂ、及び、第２ヘッダー連絡管６５ｂを通じて、室外熱交換器２３の第２熱交パス３２のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第２熱交パス３２のガス側端に送られることになる。そして、第２熱交パス３２のガス側端に送られた中間圧の冷媒は、第２熱交パス３２のガス側端から液側端に向かって第２熱交パス３２内を通過し、室外熱交換器２３の第２熱交パス３２に付着した霜を溶かす。これにより、室外熱交換器２３の第２熱交パス３２の除霜が行われる。そして、第２熱交パス３２を通過した中間圧の冷媒は、第２熱交パス３２の液側端から、第２キャピラリチューブ６３ｂを通じて、冷媒分流器６４に送られる。このとき、第２キャピラリチューブ６３ｂは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧と低圧の間の圧力まで減圧されることになる。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第１及び第３キャピラリチューブ６３ａ、６３ｃに分岐されて、第１及び第３熱交パス３１、３３の液側端に送られる。このとき、冷媒は、第１及び第３キャピラリチューブ６３ａ、６３ｃを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる。そして、第１及び第３熱交パス３１、３３の液側端に送られた低圧の冷媒は、第１及び第３熱交パス３１、３３の液側端からガス側端に向かって第１及び第３熱交パス３１、３３内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、第１及び第３熱交パス３１、３３において蒸発した低圧の冷媒は、第１及び第３熱交パス３１、３３のガス側端から、第１及び第３ヘッダー連絡管６５ａ、６５ｃ、第１及び第３ヘッダー側熱交パス選択弁７４ａ、７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第２熱交パス３２の除霜が開始される。そして、第２熱交パス３２の除霜は、第２熱交パス３２の除霜が完了するまで行われる（ステップＳ５）。ここでは、第２熱交パス３２の除霜時間ｔ２が、予め設定された所定時間（すなわち、第２熱交パス３２の除霜が完了したとみなすことができる時間）を経過するまで行われる。尚、第２熱交パス３２と他の熱交パス３１、３３とでは、上下方向位置が異なっているため、除霜が完了したとみなすことができる時間も異なることになる。このため、第２熱交パス３２の除霜の所定時間を他の熱交パス３１、３３の除霜の所定時間と異ならせるようにすることが好ましい。ここでは、熱交パス３１～３３の室外ファン２５に対する位置関係が異なっており、熱交パス３１～３３を通過する室外空気の風量に偏りが生じるため、風量が多い熱交パスのほうが着霜量が多くなる傾向にある。このため、風量が多い熱交パスの除霜の所定時間を風量が少ない熱交換パスの除霜の所定時間よりも長くすることが考えられる。 In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same manner as in the defrosting of the first heat exchange path 31, and in the indoor heat exchanger 41 Heat is exchanged with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends it to the outdoor heat exchanger 23. The intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71. The intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the second heat exchange path branch pipe 72b, the second branch pipe side heat exchange path selection valve 73b, and the second header communication pipe 65b. It is sent to the gas side end of the second heat exchange path 32 of the heat exchanger 23. Thus, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the second heat exchange path 32 without flowing into the refrigerant flow divider 64. Then, the intermediate-pressure refrigerant sent to the gas side end of the second heat exchange path 32 passes through the second heat exchange path 32 from the gas side end of the second heat exchange path 32 toward the liquid side end, The frost adhering to the second heat exchange path 32 of the outdoor heat exchanger 23 is melted. Thereby, the 2nd heat exchange path 32 of the outdoor heat exchanger 23 is defrosted. The intermediate-pressure refrigerant that has passed through the second heat exchange path 32 is sent from the liquid side end of the second heat exchange path 32 to the refrigerant flow divider 64 through the second capillary tube 63b. At this time, the second capillary tube 63b has a flow rate of intermediate pressure refrigerant that is larger than that during cooling operation or heating operation. Therefore, the second capillary tube 63b has a pressure loss as compared with the case where the refrigerant flows during cooling operation or heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle. The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and third capillary tubes 63a, since the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the first and third heat exchange paths 31, 33. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and third capillary tubes 63a and 63c. The low-pressure refrigerant sent to the liquid side ends of the first and third heat exchange paths 31 and 33 is first from the liquid side ends of the first and third heat exchange paths 31 and 33 toward the gas side end. And passes through the third heat exchange paths 31 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. Then, the low-pressure refrigerant evaporated in the first and third heat exchange paths 31 and 33 flows from the gas side ends of the first and third heat exchange paths 31 and 33 to the first and third header communication pipes 65a and 65c, The air is again sucked into the compressor 21 through the first and third header side heat exchange path selection valves 74 a and 74 c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the second heat exchange path 32 is started while continuing the indoor heating. And the defrosting of the 2nd heat exchange path 32 is performed until the defrosting of the 2nd heat exchange path 32 is completed (step S5). Here, the defrosting time t2 of the second heat exchange path 32 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the second heat exchange path 32 can be considered completed) has elapsed. . Since the second heat exchange path 32 and the other heat exchange paths 31 and 33 have different vertical positions, the time during which it can be considered that the defrosting has been completed is also different. For this reason, it is preferable to make the predetermined time for defrosting the second heat exchange path 32 different from the predetermined time for defrosting the other heat exchange paths 31 and 33. Here, the positional relationship of the heat exchange paths 31 to 33 with respect to the outdoor fan 25 is different, and the air volume of the outdoor air passing through the heat exchange paths 31 to 33 is biased. Therefore, the heat exchange path with a larger air volume is frosted. The amount tends to increase. For this reason, it can be considered that the predetermined time for defrosting the heat exchange path with a large air volume is longer than the predetermined time for defrosting the heat exchange path with a small air volume.
　第３熱交パス３３の除霜（ステップＳ６）は、第１及び第２熱交パス３１、３２と同様に、デフロスト用流路機構２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第３分岐管側熱交パス選択弁７３ｃが開けられ、第１及び第２分岐管側熱交パス選択弁７３ａ、７３ｂが閉止され、第３ヘッダー側熱交パス選択弁７４ｃが閉止され、第１及び第２ヘッダー側熱交パス選択弁７４ａ、７４ｂが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第３熱交パス３３の除霜の開始前までは第２熱交パス３２の除霜が行われていることから、第３分岐管側熱交パス選択弁７３ｃを開け、第２分岐管側熱交パス選択弁７３ｂを閉止し、第２ヘッダー側熱交パス選択弁７４ｂを開け、第３ヘッダー側熱交パス選択弁７４ｃを閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構２６の熱交パス供給管７１及び第３熱交パス分岐管７２ｃに冷媒が流れる状態となる。 The defrosting (step S6) of the third heat exchange path 33 is performed by opening and closing the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 26, as in the first and second heat exchange paths 31 and 32. This is done by switching the state. Specifically, the third branch pipe side heat exchange path selection valve 73c is opened, the first and second branch pipe side heat exchange path selection valves 73a and 73b are closed, and the third header side heat exchange path selection valve 74c is closed. Is closed, the first and second header side heat exchange path selection valves 74a and 74b are opened, and the branch pipe side selection valve 75 is switched to a closed state. Here, since the defrosting of the second heat exchange path 32 is performed before the start of the defrosting of the third heat exchange path 33, the third branch pipe side heat exchange path selection valve 73c is opened, A switching operation is performed in which the second branch pipe side heat exchange path selection valve 73b is closed, the second header side heat exchange path selection valve 74b is opened, and the third header side heat exchange path selection valve 74c is closed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the third heat exchange path branch pipe 72c of the defrost flow path mechanism 26.
　このような状態の冷媒回路１０において、冷凍サイクルにおける低圧の冷媒は、第１及び第２熱交パス３１、３２の除霜時と同様に、圧縮機２１において冷凍サイクルにおける高圧まで圧縮され、室内熱交換器４１において室内空気と熱交換を行って放熱し、膨張弁２４において冷凍サイクルにおける中間圧まで減圧され、室外熱交換器２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第３熱交パス分岐管７２ｃ、第３分岐管側熱交パス選択弁７３ｃ、及び、第３ヘッダー連絡管６５ｃを通じて、室外熱交換器２３の第３熱交パス３３のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第３熱交パス３３のガス側端に送られることになる。そして、第３熱交パス３３のガス側端に送られた中間圧の冷媒は、第３熱交パス３３のガス側端から液側端に向かって第３熱交パス３３内を通過し、室外熱交換器２３の第３熱交パス３３に付着した霜を溶かす。これにより、室外熱交換器２３の第３熱交パス３３の除霜が行われる。そして、第３熱交パス３３を通過した中間圧の冷媒は、第３熱交パス３３の液側端から、第３キャピラリチューブ６３ｃを通じて、冷媒分流器６４に送られる。このとき、第３キャピラリチューブ６３ｃは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧と低圧の間の圧力まで減圧されることになる。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第１及び第２キャピラリチューブ６３ａ、６３ｂに分岐されて、第１及び第２熱交パス３１、３２の液側端に送られる。このとき、冷媒は、第１及び第２キャピラリチューブ６３ａ、６３ｂを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる。そして、第１及び第２熱交パス３１、３２の液側端に送られた低圧の冷媒は、第１及び第２熱交パス３１、３２の液側端からガス側端に向かって第１及び第２熱交パス３１、３２内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、第１及び第２熱交パス３１、３２において蒸発した低圧の冷媒は、第１及び第２熱交パス３１、３２のガス側端から、第１及び第２ヘッダー連絡管６５ａ、６５ｂ、第１及び第２ヘッダー側熱交パス選択弁７４ａ、７４ｂ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第３熱交パス３３の除霜が開始される。そして、第３熱交パス３３の除霜は、第２熱交パス３３の除霜が完了するまで行われる（ステップＳ７）。ここでは、第３熱交パス３３の除霜時間ｔ３が、予め設定された所定時間（すなわち、第３熱交パス３３の除霜が完了したとみなすことができる時間）を経過するまで行われる。尚、第３熱交パス３３の除霜の所定時間についても、熱交パス３１～３３の室外ファン２５に対する位置関係等を考慮して、他の熱交パス３１、３２の除霜の所定時間と異ならせるようにすることが好ましい。 In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same way as when the first and second heat exchange paths 31 and 32 are defrosted. The heat exchanger 41 exchanges heat with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends the heat to the outdoor heat exchanger 23. The intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the heat exchange path supply pipe 71. The intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the third heat exchange path branch pipe 72c, the third branch pipe side heat exchange path selection valve 73c, and the third header communication pipe 65c. It is sent to the gas side end of the third heat exchange path 33 of the heat exchanger 23. Thus, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the third heat exchange path 33 without flowing into the refrigerant flow divider 64. The intermediate pressure refrigerant sent to the gas side end of the third heat exchange path 33 passes through the third heat exchange path 33 from the gas side end of the third heat exchange path 33 toward the liquid side end, The frost adhering to the third heat exchange path 33 of the outdoor heat exchanger 23 is melted. Thereby, the 3rd heat exchange path 33 of the outdoor heat exchanger 23 is defrosted. Then, the intermediate-pressure refrigerant that has passed through the third heat exchange path 33 is sent from the liquid side end of the third heat exchange path 33 to the refrigerant flow divider 64 through the third capillary tube 63c. At this time, in the third capillary tube 63c, an intermediate pressure refrigerant having a larger flow rate than in the cooling operation or the heating operation flows, so that the pressure loss is smaller than that in the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle. The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and second capillary tubes 63a, because the flow dividing pipe side selection valve 75 is closed. Branched to 63 b and sent to the liquid side ends of the first and second heat exchange paths 31 and 32. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and second capillary tubes 63a and 63b. The low-pressure refrigerant sent to the liquid side ends of the first and second heat exchange paths 31 and 32 is first from the liquid side ends of the first and second heat exchange paths 31 and 32 toward the gas side ends. Then, it passes through the second heat exchange paths 31 and 32 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. The low-pressure refrigerant evaporated in the first and second heat exchange paths 31 and 32 flows from the gas side ends of the first and second heat exchange paths 31 and 32 to the first and second header communication pipes 65a and 65b, The air is again sucked into the compressor 21 through the first and second header side heat exchange path selection valves 74a and 74b, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the third heat exchange path 33 is started while continuing the indoor heating. And the defrosting of the 3rd heat exchange path 33 is performed until the defrosting of the 2nd heat exchange path 33 is completed (step S7). Here, the defrosting time t3 of the third heat exchange path 33 is performed until a predetermined time set in advance (that is, a time during which the defrosting of the third heat exchange path 33 can be considered completed) has elapsed. . The predetermined time for defrosting the third heat exchange path 33 is also determined in consideration of the positional relationship of the heat exchange paths 31 to 33 with respect to the outdoor fan 25 and the like. It is preferable to make them different from each other.
　そして、上記のステップＳ２～Ｓ７の処理によって室外熱交換器２３のすべての熱交パス３１～３３の除霜が完了した後に、暖房運転に復帰する（ステップＳ８）。
　以上のように、デフロスト用流路機構２６によって、熱交パス３１～３３のうちの任意の熱交パスの除霜を行いつつ、室内熱交換器４１から室外熱交換器２３に送られる冷媒を蒸発させる暖房デフロスト運転を行っている。そして、この暖房デフロスト運転を複数の熱交パス３１～３３に対して順次行うことによって、室内の暖房を継続しつつ、室外熱交換器２３全体の除霜を行っている。
　（特徴）
　本実施形態の空気調和装置１には、以下のような特徴がある。
　空気調和装置１は、上記のように、冷媒を圧縮する圧縮機２１と、圧縮機２１において圧縮された冷媒の放熱を行う室内熱交換器４１と、室内熱交換器４１において放熱した冷媒を室外空気との熱交換によって蒸発させる室外熱交換器２３と、が順次接続されることによって構成されている。空気調和装置１は、圧縮機２１、室内熱交換器４１、室外熱交換器２３、圧縮機２１の順に冷媒を循環させる暖房運転を行うことが可能である。室外熱交換器２３は、互いが並列に接続された複数（ここでは、３つ）の熱交パス３１～３３を有している。複数の熱交パス３１～３３の液側端は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を複数の熱交パス３１～３３の液側端に分岐するための冷媒分流器６４によって並列に接続されている。 Then, after the defrosting of all the heat exchange paths 31 to 33 of the outdoor heat exchanger 23 is completed by the processing of steps S2 to S7, the heating operation is resumed (step S8).
As described above, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is defrosted by the defrost flow path mechanism 26 while defrosting any of the heat exchange paths 31 to 33. Evaporative heating operation is performed. The heating defrosting operation is sequentially performed on the plurality of heat exchange paths 31 to 33, so that the entire outdoor heat exchanger 23 is defrosted while the indoor heating is continued.
(Characteristic)
The air conditioner 1 of the present embodiment has the following characteristics.
As described above, the air conditioner 1 includes the compressor 21 that compresses the refrigerant, the indoor heat exchanger 41 that radiates the refrigerant compressed in the compressor 21, and the refrigerant that has radiated heat in the indoor heat exchanger 41. An outdoor heat exchanger 23 that is evaporated by heat exchange with air is sequentially connected. The air conditioner 1 can perform a heating operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 23, and the compressor 21. The outdoor heat exchanger 23 has a plurality (here, three) of heat exchange paths 31 to 33 connected in parallel to each other. The liquid side ends of the plurality of heat exchange paths 31 to 33 are refrigerant distributors for branching the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 to the liquid side ends of the plurality of heat exchange paths 31 to 33. 64 are connected in parallel.
　そして、空気調和装置１には、上記の構成を前提として、室内熱交換器４１から室外熱交換器２３に送られる冷媒を、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送るためのデフロスト用流路機構２６がさらに設けられている。そして、空気調和装置１では、デフロスト用流路機構２６によって、任意の熱交パスの除霜を行いつつ、室内熱交換器４１から室外熱交換器２３に送られる冷媒を蒸発させる暖房デフロスト運転を行うようになっている。この暖房デフロスト運転は、まず、室内熱交換器４１から室外熱交換器２３に送られる冷媒を、デフロスト用流路機構２６によって、冷媒分流器６４に流入させることなく、任意の熱交パスのガス側端から液側端に向かって任意の熱交パス内を通過させる。次に、任意の熱交パスを通過した冷媒を、冷媒分流器６４を通じて、任意の熱交パス以外の他の熱交パスの液側端からガス側端に向かって他の熱交パス内を通過させる。そして、空気調和装置１では、デフロスト用流路機構２６を用いた暖房デフロスト運転を複数の熱交パス３１～３３に対して順次行うことによって、室外熱交換器２３全体の除霜を行うことができるようになっている。 In the air conditioner 1, on the premise of the above configuration, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 does not flow into the refrigerant diverter 64, and the plurality of heat exchange paths 31 to A defrost channel mechanism 26 is further provided for sending to the gas side end of the heat exchange path arbitrarily selected from among 33. In the air conditioning apparatus 1, the defrosting flow path mechanism 26 performs a heating defrost operation in which the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is evaporated while defrosting an arbitrary heat exchange path. To do. In this heating defrost operation, first, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is not allowed to flow into the refrigerant diverter 64 by the defrost flow path mechanism 26, and the gas in any heat exchange path. It passes through an arbitrary heat exchange path from the side end toward the liquid side end. Next, the refrigerant that has passed through the arbitrary heat exchange path passes through the refrigerant flow divider 64 in the other heat exchange path from the liquid side end of the other heat exchange path other than the arbitrary heat exchange path toward the gas side end. Let it pass. In the air conditioner 1, the entire outdoor heat exchanger 23 can be defrosted by sequentially performing the heating defrost operation using the defrost flow path mechanism 26 on the plurality of heat exchange paths 31 to 33. It can be done.
　一方で、特許文献１のデフロスト方式では、室外熱交換器の複数の熱交パスの液側端のそれぞれに電磁弁を設け、任意に選択された熱交パスの電磁弁を閉止することで、この熱交パス内における冷媒の流れを止めて、室外空気の熱によって、任意の熱交パスの除霜を行うようにしている。また、特許文献２のデフロスト方式では、圧縮機から吐出された冷媒の一部を、室内熱交換器に送らずに室外熱交換器の複数の熱交パスの液側端に送るためのバイパス路を設け、このバイパス路を通じて、圧縮機から吐出された冷媒の一部を、室内熱交換器に送らずに室外熱交換器の任意の熱交パスに送ることによって、冷媒の熱によって、任意の熱交パスの除霜を行うようにしている（図９を参照）。ここで、図９は、従来（特許文献２）のデフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。 On the other hand, in the defrost method of Patent Document 1, an electromagnetic valve is provided at each of the liquid side ends of the plurality of heat exchange paths of the outdoor heat exchanger, and the electromagnetic valve of the arbitrarily selected heat exchange path is closed. The flow of the refrigerant in the heat exchange path is stopped, and any heat exchange path is defrosted by the heat of the outdoor air. Moreover, in the defrost system of patent document 2, the bypass path for sending some refrigerant | coolants discharged from the compressor to the liquid side end of the several heat exchanger path | pass of an outdoor heat exchanger, without sending to an indoor heat exchanger And through the bypass, a part of the refrigerant discharged from the compressor is sent to any heat exchange path of the outdoor heat exchanger without being sent to the indoor heat exchanger. The heat exchange path is defrosted (see FIG. 9). Here, FIG. 9 is a pressure-enthalpy diagram illustrating a conventional refrigeration cycle during defrost operation (Patent Document 2).
　これに対して、空気調和装置１における暖房デフロスト運転では、上記のように、圧縮機２１において圧縮された冷媒の全流量を室内熱交換器４１に送って暖房に使用し（図７及び図８の点Ｂから点Ｃまでの行程を参照）、その後、室内熱交換器４１から室外熱交換器２３に送られる冷媒の熱によって除霜を行うようにしている（図７及び図８の点Ｄから点Ｅまでの行程を参照）。
　したがって、空気調和装置１では、特許文献２のデフロスト方式とは異なり、圧縮機２１において圧縮された冷媒の全流量を室内の暖房に供することになるため、暖房能力をほとんど低下させることがない。しかも、空気調和装置１では、特許文献１、２のデフロスト方式とは異なり、圧縮機２１において圧縮された冷媒の全流量を室外熱交換器２３の任意の熱交パスの除霜に供することになるため、高い除霜能力を得ることができる。これにより、特許文献１、２のデフロスト方式よりも、除霜を短時間で完了し、暖房を行っている時間を長くして、積分的な暖房能力を高めることができる。さらに、空気調和装置１では、特許文献１のデフロスト方式とは異なり、冷媒の熱を除霜に使用することになるため、外気温度が０℃以下の気象条件においても、室外熱交換器２３の除霜を行うことができる。 In contrast, in the heating defrost operation in the air conditioner 1, as described above, the entire flow rate of the refrigerant compressed in the compressor 21 is sent to the indoor heat exchanger 41 and used for heating (FIGS. 7 and 8). Then, defrosting is performed by the heat of the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 (see point D in FIGS. 7 and 8). To the point E).
Therefore, in the air conditioner 1, unlike the defrost system disclosed in Patent Document 2, the entire flow rate of the refrigerant compressed in the compressor 21 is used for indoor heating, so that the heating capacity is hardly reduced. Moreover, in the air conditioner 1, unlike the defrost methods of Patent Documents 1 and 2, the total flow rate of the refrigerant compressed in the compressor 21 is used for defrosting an arbitrary heat exchange path of the outdoor heat exchanger 23. Therefore, a high defrosting capability can be obtained. Thereby, compared with the defrost system of patent documents 1 and 2, defrosting is completed in a short time, the time which is heating can be lengthened, and integral heating capability can be raised. Furthermore, in the air conditioner 1, unlike the defrost method of Patent Document 1, the heat of the refrigerant is used for defrosting. Therefore, the outdoor heat exchanger 23 can be used even in weather conditions where the outside air temperature is 0 ° C. or less. Defrosting can be performed.
　また、空気調和装置１では、室外熱交換器２３の上部を構成する熱交パス（ここでは、第１熱交パス３１）から下部を構成する熱交パス（ここでは、第３熱交パス３３）に向けて行うようにしている。このため、除霜によって発生するドレン水をユニットケーシング５１の底板５２までスムーズに排水することができる。
　また、空気調和装置１では、室外熱交換器２３を構成する熱交パス３１～３３の除霜を、熱交パスの位置の違いを考慮して設定された所定時間だけ行うようにしている。ここでは、熱交パス３１～３３の室外ファン２５に対する位置の違いによる熱交パス３１～３３を通過する室外空気の風量に偏りを考慮して、風量の多い熱交パスの除霜の所定時間を風量が少ない熱交換パスの除霜の所定時間よりも長くするようにしている。このため、風量が多いことから着霜量が多くなる熱交パスの除霜の所定時間を長くし、風量が少ないことから着霜量が少なくなる熱交パスの除霜の所定時間を短くすることができ、これにより、熱交パスの位置の違いを考慮した適切な所定時間で適切に除霜を行うことができる。 In the air conditioner 1, the heat exchange path (here, the first heat exchange path 31) constituting the upper part of the outdoor heat exchanger 23 to the heat exchange path (here, the third heat exchange path 33) constituting the lower part. ). For this reason, drain water generated by defrosting can be smoothly drained to the bottom plate 52 of the unit casing 51.
In the air conditioner 1, the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 are defrosted for a predetermined time set in consideration of the position of the heat exchange path. Here, a predetermined time for defrosting the heat exchange path with a large air volume is considered in consideration of the bias in the air volume of the outdoor air passing through the heat exchange paths 31 to 33 due to the difference in position of the heat exchange paths 31 to 33 with respect to the outdoor fan 25. Is set longer than a predetermined time for defrosting the heat exchange path with a small air volume. For this reason, the predetermined time of defrosting of the heat exchange path where the amount of frost increases because the air volume is large is shortened, and the predetermined time of defrosting of the heat exchange path where the amount of frost decreases because the air volume is small Thus, it is possible to appropriately perform defrosting in an appropriate predetermined time in consideration of the difference in the position of the heat exchange path.
　（変形例１）
　上記実施形態の暖房デフロスト運転では、図６のステップＳ３、Ｓ５、Ｓ７に示すように、各熱交パス３１～３３の除霜を、除霜時間ｔ１～ｔ３が予め設定された所定時間を経過するまで行うようにしているが、これに限定されるものではない。
　例えば、図１０に示すように、室外熱交換器２３を構成する複数（ここでは、３つ）の熱交パス３１～３３のうち最初に除霜を行う第１熱交パス３１の除霜を、室外熱交温度センサ６７によって検出される飽和温度Ｔｓａｔが所定温度以上に上昇するまで行う（ステップＳ１１）。ここで、この所定温度は、第１熱交パス３１の除霜が完了したとみなすことができる温度に設定される。そして、このときの除霜時間ｔ１を計測しておき、この除霜時間ｔ１から第２及び第３熱交パス３２、３３の除霜の所定時間を設定し（ステップＳ１２）、第２及び第３熱交パス３２、３３の除霜を、この設定された所定時間だけ行うようにしてもよい（ステップＳ５、Ｓ７）。このとき、第２及び第３熱交パス３２、３３の所定時間については、第１熱交パス３１と同じ除霜時間ｔ１に設定してもよいし、また、熱交パスの位置の違いをさらに考慮して設定するようにしてもよい。尚、図１０は、本変形例にかかる暖房デフロスト運転のフローチャートである。 (Modification 1)
In the heating defrost operation of the above embodiment, as shown in steps S3, S5, and S7 in FIG. 6, the defrosting of the heat exchange paths 31 to 33 is performed after a predetermined time in which the defrosting times t1 to t3 are set in advance. However, the present invention is not limited to this.
For example, as shown in FIG. 10, the defrosting of the first heat exchange path 31 that performs defrosting first among the plurality (three in this case) of heat exchange paths 31 to 33 constituting the outdoor heat exchanger 23 is performed. This is performed until the saturation temperature Tsat detected by the outdoor heat exchange temperature sensor 67 rises above a predetermined temperature (step S11). Here, this predetermined temperature is set to a temperature at which defrosting of the first heat exchange path 31 can be considered completed. And the defrost time t1 at this time is measured, the predetermined time of the defrost of the 2nd and 3rd heat exchange paths 32 and 33 is set from this defrost time t1 (step S12), and the 2nd and 2nd The defrosting of the three heat exchange paths 32 and 33 may be performed only for the set predetermined time (steps S5 and S7). At this time, about the predetermined time of the 2nd and 3rd heat exchange paths 32 and 33, you may set to the same defrost time t1 as the 1st heat exchange path 31, and also the difference in the position of a heat exchange path Further, it may be set in consideration. FIG. 10 is a flowchart of the heating defrost operation according to this modification.
　このように、本変形例の暖房デフロスト運転では、各熱交パスの除霜の完了を時間だけで判定する上記の暖房デフロスト運転とは異なっている。具体的には、本変形例の暖房デフロスト運転では、最初に除霜を行う熱交パスについては、温度変化から除霜の完了を検知し、このときに実際に除霜に要した時間から得られた所定時間によって他の熱交パスの除霜の完了を判定するようにしている。
　このため、本変形例の暖房デフロスト運転では、室外熱交換器２３の着霜状態に応じて、暖房デフロスト運転毎に、各熱交パスの除霜の所要時間が設定されることになる。したがって、本変形例の暖房デフロスト運転では、予め設定された所定時間になるまで各熱交パスの除霜を行う場合に比べて、暖房デフロスト運転毎に各熱交パスの除霜の所定時間を適切に設定することができる。 Thus, the heating defrost operation of the present modification is different from the heating defrost operation in which the completion of defrosting of each heat exchange path is determined only by time. Specifically, in the heating defrost operation of the present modification, for the heat exchange path that performs defrosting first, the completion of defrosting is detected from the temperature change, and this time is obtained from the time actually required for defrosting. The completion of defrosting of the other heat exchange path is determined based on the predetermined time.
For this reason, in the heating defrost operation of this modification, the time required for defrosting of each heat exchange path is set for each heating defrost operation according to the frosting state of the outdoor heat exchanger 23. Therefore, in the heating defrost operation of this modification, the predetermined time for defrosting of each heat exchange path is set for each heating defrost operation, compared to the case where the defrosting of each heat exchange path is performed until a predetermined time set in advance. It can be set appropriately.
　（変形例２）
　上記実施形態及び変形例１にかかる空気調和装置１では、デフロスト用流路機構２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。
　例えば、図１１及び図１２に示すように、分岐管側熱交パス選択弁７３ａ～７３ｃを一体化した切換弁７７を使用するようにしてもよい。ここで、切換弁７７は、熱交パス供給管７１を流れる冷媒を熱交パス分岐管７２ａ～７２ｃのいずれに送るか、又は、いずれの熱交パス分岐管７２ａ～７２ｃにも冷媒を送らないことを選択する機能を有する切換弁である。ここでは、切換弁７７として、ロータリー式の切換弁が使用されている。この切換弁７７は、熱交パス供給管７１及び熱交パス分岐管７２ａ～７２ｃに接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃに代えて切換弁７７が制御部８に接続されている。尚、図１１は、本変形例にかかる空気調和装置１の概略構成図であり、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図１２は、本変形例の暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 2)
In the air conditioner 1 according to the embodiment and the first modification, the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
For example, as shown in FIGS. 11 and 12, a switching valve 77 in which branch pipe side heat exchange path selection valves 73a to 73c are integrated may be used. Here, the switching valve 77 sends the refrigerant flowing through the heat exchange path supply pipe 71 to any of the heat exchange path branch pipes 72a to 72c, or does not send the refrigerant to any of the heat exchange path branch pipes 72a to 72c. This is a switching valve having a function of selecting this. Here, a rotary type switching valve is used as the switching valve 77. The switching valve 77 is connected to the heat exchange path supply pipe 71 and the heat exchange path branch pipes 72a to 72c. In the configuration of the present modification, a switching valve 77 is connected to the control unit 8 instead of the branch pipe side heat exchange path selection valves 73a to 73c in the control block diagram of FIG. FIG. 11 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation. FIG. 12 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
　このような構成であっても、図１１に示すように、いずれの熱交パス分岐管７２ａ～７２ｃにも冷媒を送らないように切換弁７７を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁７７の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図１２に示すように、熱交パス供給管７１を流れる冷媒を熱交パス分岐管７２ａ～７２ｃのいずれかに送るように切換弁７７を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成に比べて、デフロスト用流路機構２６を構成する部品点数を減らすことができる。
　（変形例３）
　上記実施形態及び変形例１にかかる空気調和装置１では、デフロスト用流路機構２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。 Even in such a configuration, as shown in FIG. 11, by operating the switching valve 77 so as not to send the refrigerant to any of the heat exchange path branch pipes 72a to 72c, the same heating as in the above embodiment is performed. You can drive. Further, in the operation state of the switching valve 77 similar to that in the heating operation, the same cooling operation as in the above embodiment can be performed. Then, as shown in FIG. 12, the switching valve 77 is operated so as to send the refrigerant flowing through the heat exchange path supply pipe 71 to any one of the heat exchange path branch pipes 72a to 72c. The same heating defrost operation can be performed.
And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, the number of parts which comprise the flow-path mechanism 26 for defrost can be reduced.
(Modification 3)
In the air conditioner 1 according to the embodiment and the first modification, the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
　例えば、図１３及び図１４に示すように、熱交パス供給管７１と、分岐管側熱交パス選択弁７３ａ～７３ｃと、分流管側選択弁７５とを一体化した切換弁７８を使用するようにしてもよい。ここで、切換弁７８は、液冷媒管２７を流れる冷媒を冷媒分流管６４に流すか又は熱交パス分岐管７２ａ～７２ｃのいずれかに送るかを選択し、熱交パス分岐管７２ａ～７２ｃのいずれかに送る場合には、冷媒を熱交パス分岐管７２ａ～７２ｃのいずれに送るかを選択する機能を有する切換弁である。ここでは、切換弁７８として、ロータリー式の切換弁が使用されている。この切換弁７８は、液冷媒管２７、冷媒分流管６４及び熱交パス分岐管７２ａ～７２ｃに接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ及び分流管側選択弁７５に代えて切換弁７８が制御部８に接続されている。尚、図１３は、本変形例にかかる空気調和装置１の概略構成図であり、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図１４は、本変形例の暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 For example, as shown in FIGS. 13 and 14, a switching valve 78 in which a heat exchange path supply pipe 71, branch pipe side heat exchange path selection valves 73a to 73c, and a branch pipe side selection valve 75 are integrated is used. You may do it. Here, the switching valve 78 selects whether the refrigerant flowing through the liquid refrigerant pipe 27 flows to the refrigerant distribution pipe 64 or sent to any one of the heat exchange path branch pipes 72a to 72c, and the heat exchange path branch pipes 72a to 72c. In this case, the switching valve has a function of selecting which one of the heat exchange path branch pipes 72a to 72c is sent with the refrigerant. Here, a rotary type switching valve is used as the switching valve 78. The switching valve 78 is connected to the liquid refrigerant pipe 27, the refrigerant distribution pipe 64, and the heat exchange path branch pipes 72a to 72c. In the configuration of this modification, a switching valve 78 is connected to the control unit 8 in place of the branch pipe side heat exchange path selection valves 73a to 73c and the branch pipe side selection valve 75 in the control block diagram of FIG. . FIG. 13 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation. FIG. 14 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 (when defrosting the first heat exchange path 31) during the heating defrost operation of the present modification.
　このような構成であっても、図１３に示すように、液冷媒管２７を流れる冷媒を冷媒分流管６４に流すように切換弁７８を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁７８の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図１４に示すように、液冷媒管２７を流れる冷媒を冷媒分流管６４に流さずに熱交パス分岐管７２ａ～７２ｃのいずれかに送るように切換弁７８を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成、さらには、変形例２の構成に比べて、デフロスト用流路機構２６を構成する部品点数を減らすことができる。
　（変形例４）
　上記実施形態及び変形例１にかかる空気調和装置１では、デフロスト用流路機構２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。 Even in such a configuration, as shown in FIG. 13, by operating the switching valve 78 so that the refrigerant flowing through the liquid refrigerant pipe 27 flows through the refrigerant distribution pipe 64, the heating operation similar to that in the above embodiment is performed. It can be carried out. Further, in the operation state of the switching valve 78 similar to that in the heating operation, the same cooling operation as in the above embodiment can be performed. Then, as shown in FIG. 14, the switching valve 78 is operated so as to send the refrigerant flowing through the liquid refrigerant pipe 27 to any one of the heat exchange path branch pipes 72a to 72c without flowing the refrigerant into the refrigerant distribution pipe 64. The heating defrost operation similar to the embodiment or the first modification can be performed.
And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, and also the structure of the modification 2, the number of parts which comprise the flow-path mechanism 26 for defrost can be reduced.
(Modification 4)
In the air conditioner 1 according to the embodiment and the first modification, the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
　例えば、図１５及び図１６に示すように、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、ヘッダー６６とを一体化した切換弁７９を使用するようにしてもよい。ここで、切換弁７９は、熱交パス供給管７１を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、熱交パス供給管７１を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するか、又は、いずれのヘッダー連絡管６５ａ～６５ｃにも冷媒を送らないことを選択する機能を有する切換弁である。ここでは、切換弁７９として、ロータリー式の切換弁が使用されている。この切換弁７９は、熱交パス供給管７１、ヘッダー連絡管６５ａ～６５ｃ及びガス冷媒管２８に接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ及びヘッダー側熱交パス選択弁７４ａ～７４ｃに代えて切換弁７９が制御部８に接続されている。尚、図１５は、本変形例にかかる空気調和装置１の概略構成図であり、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図１６は、本変形例の暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 For example, as shown in FIGS. 15 and 16, the heat exchange path branch pipes 72a to 72c, the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the header 66 Alternatively, a switching valve 79 may be used. Here, the switching valve 79 selects which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication pipe to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent. The other header communication pipes are switching valves having a function of connecting to the gas refrigerant pipe 28 or selecting not to send the refrigerant to any of the header communication pipes 65a to 65c. Here, a rotary switching valve is used as the switching valve 79. The switching valve 79 is connected to the heat exchange path supply pipe 71, the header communication pipes 65 a to 65 c and the gas refrigerant pipe 28. In the configuration of this modified example, in the control block diagram of FIG. 2, a switching valve 79 is provided in the control unit 8 instead of the branch pipe side heat exchange path selection valves 73a to 73c and the header side heat exchange path selection valves 74a to 74c. It is connected. FIG. 15 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation. FIG. 16 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
　このような構成であっても、図１５に示すように、いずれのヘッダー連絡管６５ａ～６５ｃにも冷媒を送らないように切換弁７９を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁７９の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図１６に示すように、熱交パス供給管７１を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、熱交パス供給管７１を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁７９を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成、さらには、変形例２、３の構成に比べて、デフロスト用流路機構２６を構成する部品点数を減らすことができる。 Even in such a configuration, as shown in FIG. 15, by operating the switching valve 79 so that the refrigerant is not sent to any of the header communication pipes 65a to 65c, the heating operation similar to the above embodiment is performed. It can be carried out. In addition, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 79 similar to that in the heating operation. Then, as shown in FIG. 16, it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent. By operating the switching valve 79 so that the header communication pipes other than the pipes are connected to the gas refrigerant pipe 28, the heating defrost operation similar to that of the above-described embodiment or modification 1 can be performed.
And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, and the structure of the modifications 2, 3, the number of parts which comprise the flow-path mechanism 26 for defrost can be reduced.
　（変形例５）
　上記実施形態及び変形例１にかかる空気調和装置１では、デフロスト用流路機構２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。
　例えば、図１７及び図１８に示すように、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５と、ヘッダー６６とを一体化した切換弁８０を使用するようにしてもよい。ここで、切換弁８０は、液冷媒管２７を流れる冷媒を冷媒分流管６４に流すか又はヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、液冷媒管２７を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続する機能を有する切換弁である。ここでは、切換弁８０として、ロータリー式の切換弁が使用されている。この切換弁８０は、液冷媒管２７、冷媒分流管６４、ヘッダー連絡管６５ａ～６５ｃ及びガス冷媒管２８に接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ及び分流管側選択弁７５に代えて切換弁８０が制御部８に接続されている。尚、図１７は、本変形例にかかる空気調和装置１の概略構成図であり、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図１８は、本変形例の暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 5)
In the air conditioner 1 according to the embodiment and the first modification, the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
For example, as shown in FIGS. 17 and 18, a heat exchange path supply pipe 71, heat exchange path branch pipes 72a to 72c, branch pipe side heat exchange path selection valves 73a to 73c, and a header side heat exchange path selection valve. A switching valve 80 in which 74a to 74c, the branch pipe side selection valve 75, and the header 66 are integrated may be used. Here, the switching valve 80 selects whether the refrigerant flowing through the liquid refrigerant pipe 27 flows to the refrigerant distribution pipe 64 or the header communication pipes 65a to 65c, and the refrigerant flowing through the liquid refrigerant pipe 27 is sent. A header connecting pipe other than the header connecting pipe is a switching valve having a function of connecting to the gas refrigerant pipe 28. Here, a rotary switching valve is used as the switching valve 80. This switching valve 80 is connected to the liquid refrigerant pipe 27, the refrigerant distribution pipe 64, the header communication pipes 65 a to 65 c and the gas refrigerant pipe 28. In the configuration of the present modification, switching is performed in place of the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the branch pipe side selection valve 75 in the control block diagram of FIG. A valve 80 is connected to the control unit 8. FIG. 17 is a schematic configuration diagram of the air-conditioning apparatus 1 according to this modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 1 during heating operation. FIG. 18 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
　このような構成であっても、図１７に示すように、液冷媒管２７を流れる冷媒を冷媒分流管６４に流すように切換弁８０を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８０の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図１８に示すように、液冷媒管２７を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、液冷媒管２７を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁８０を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成、さらには、変形例２～４の構成に比べて、デフロスト用流路機構２６を構成する部品点数を減らすことができる。 Even in such a configuration, as shown in FIG. 17, by operating the switching valve 80 so that the refrigerant flowing through the liquid refrigerant pipe 27 flows through the refrigerant distribution pipe 64, the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 80 similar to that in the heating operation. Then, as shown in FIG. 18, a header other than the header communication pipe to which the refrigerant flowing through the liquid refrigerant pipe 27 is selected to be sent to any of the header communication pipes 65a to 65c and the refrigerant flowing through the liquid refrigerant pipe 27 is sent. By operating the switching valve 80 so that the communication pipe is connected to the gas refrigerant pipe 28, the heating defrost operation similar to that in the above embodiment or the first modification can be performed.
In the configuration of the present modification, the number of parts constituting the defrost flow path mechanism 26 can be reduced as compared with the configurations of the above-described embodiment and the first modification, and further, the configurations of the second to fourth modifications.
　（変形例６）
　上記実施形態及び変形例１にかかる空気調和装置１では、デフロスト用流路機構２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。
　例えば、図１９及び図２０に示すように、分岐管側熱交パス選択弁７３ａ～７３ｃとヘッダー側熱交パス選択弁７４ａ～７４ｃとを一体化した切換弁８１ａ～８１ｃを使用するようにしてもよい。ここで、切換弁８１ａ～８１ｃは、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のガス側端から液側端に向かって送るか、又は、冷媒分流管６４を通じて熱交パス３１～３３内を液側端からガス側端に向かって通過した冷媒をヘッダー６６に送るかどうかを選択する機能を有する切換弁である。ここでは、切換弁８１ａ～８１ｃとして、三方弁が使用されている。これらの切換弁８１ａ～８１ｃは、熱交パス分岐管７２ａ～７２ｃ及びヘッダー連絡管６５ａ～６５ｃに接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ及びヘッダー側熱交パス選択弁７４ａ～７４ｃに代えて切換弁８１ａ～８１ｃが制御部８に接続されている。尚、図１９は、本変形例にかかる空気調和装置１の概略構成図であり、暖房運転時における空気調和装置１内の冷媒の流れを示す図である。図２０は、本変形例の暖房デフロスト運転時における空気調和装置１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 6)
In the air conditioner 1 according to the embodiment and the first modification, the defrosting flow path mechanism 26 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
For example, as shown in FIGS. 19 and 20, switching valves 81a to 81c in which branch pipe side heat exchange path selection valves 73a to 73c and header side heat exchange path selection valves 74a to 74c are integrated are used. Also good. Here, the switching valves 81a to 81c send the refrigerant flowing through the heat exchange path supply pipe 71 from the gas side end to the liquid side end of the heat exchange paths 31 to 33, or through the refrigerant distribution pipe 64. This is a switching valve having a function of selecting whether or not the refrigerant that has passed through 31 to 33 from the liquid side end toward the gas side end is sent to the header 66. Here, three-way valves are used as the switching valves 81a to 81c. These switching valves 81a to 81c are connected to the heat exchange path branch pipes 72a to 72c and the header communication pipes 65a to 65c. In the configuration of this modification, in the control block diagram of FIG. 2, the switching valves 81a to 81c are replaced by control valves in place of the branch pipe side heat exchange path selection valves 73a to 73c and the header side heat exchange path selection valves 74a to 74c. 8 is connected. FIG. 19 is a schematic configuration diagram of the air-conditioning apparatus 1 according to the present modification, and is a diagram illustrating the flow of the refrigerant in the air-conditioning apparatus 1 during the heating operation. FIG. 20 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 1 during the heating defrost operation of the present modification.
　このような構成であっても、図１９に示すように、冷媒分流管６４を通じて熱交パス３１～３３内を液側端からガス側端に向かって通過した冷媒をヘッダー６６に送るように切換弁８１ａ～８１ｃを動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８１ａ～８１ｃの動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図２０に示すように、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のガス側端から液側端に向かって送るように切換弁８１ａ～８１ｃのいずれかを動作させ、他の切換弁については、冷媒分流管６４を通じて熱交パス３１～３３内を液側端からガス側端に向かって通過した冷媒をヘッダー６６に送るように動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。 Even in such a configuration, as shown in FIG. 19, switching is performed so that the refrigerant that has passed through the heat exchange paths 31 to 33 through the refrigerant distribution pipe 64 from the liquid side end to the gas side end is sent to the header 66. By operating the valves 81a to 81c, the heating operation similar to that in the above embodiment can be performed. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valves 81a to 81c similar to that in the heating operation. Then, as shown in FIG. 20, any one of the switching valves 81a to 81c is operated so as to send the refrigerant flowing through the heat exchange path supply pipe 71 from the gas side end to the liquid side end of the heat exchange paths 31 to 33. The other switching valve is operated by sending the refrigerant that has passed through the heat exchange paths 31 to 33 through the refrigerant distribution pipe 64 from the liquid side end toward the gas side end to the header 66. A heating defrost operation similar to that of the first modification can be performed.
　そして、本変形例の構成では、上記実施形態及び変形例１の構成に比べて、デフロスト用流路機構２６を構成する部品点数を減らすことができる。
　＜第２実施形態＞
　上記第１実施形態及びその変形例では、互いが並列に接続された複数の熱交パス３１～３３を有する室外熱交換器２３に対して、本発明にかかる暖房デフロスト運転の構成を適用しているが、これに限定されるものではない。ここでは、複数の熱交パス３１～３３だけでなく、冷媒が冷媒分流器６４に流入する前に通過する過冷却パス３４を有する室外熱交換器１２３に対して、本発明にかかる暖房デフロスト運転の構成を適用してもよい。
　図２１は、本発明の第２実施形態にかかる空気調和装置１０１の概略構成図である。空気調和装置１０１は、主として、室外ユニット１０２と、室内ユニット４と、室外ユニット１０２と室内ユニット４とを接続する液冷媒連絡管５及びガス冷媒連絡管６とを有している。そして、室外ユニット１０２と室内ユニット４とは、液冷媒連絡管５及びガス冷媒連絡管６を介して接続されることによって蒸気圧縮式の冷凍サイクルを行うための冷媒回路１１０を構成している。 And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, the number of parts which comprise the flow-path mechanism 26 for defrost can be reduced.
<Second Embodiment>
In the first embodiment and the modification thereof, the configuration of the heating defrost operation according to the present invention is applied to the outdoor heat exchanger 23 having a plurality of heat exchange paths 31 to 33 connected in parallel to each other. However, it is not limited to this. Here, the heating defrost operation according to the present invention is applied not only to the plurality of heat exchange paths 31 to 33 but also to the outdoor heat exchanger 123 having the supercooling path 34 through which the refrigerant passes before flowing into the refrigerant distributor 64. The following configuration may be applied.
FIG. 21 is a schematic configuration diagram of an air-conditioning apparatus 101 according to the second embodiment of the present invention. The air conditioner 101 mainly includes an outdoor unit 102, an indoor unit 4, and a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6 that connect the outdoor unit 102 and the indoor unit 4. The outdoor unit 102 and the indoor unit 4 constitute a refrigerant circuit 110 for performing a vapor compression refrigeration cycle by being connected via a liquid refrigerant communication pipe 5 and a gas refrigerant communication pipe 6.
　（室内ユニット）
　室内ユニット４は、室内に設置されており、冷媒回路１１０の一部を構成している。室内ユニット４は、主として、室内熱交換器４１を有している。尚、室内ユニット４の構成は、第１実施形態の室内ユニット４の構成と同様であるため、ここでは説明を省略する。
　（室外ユニット）
　室外ユニット１０２は、室外に設置されており、冷媒回路１１０の一部を構成している。室外ユニット１０２は、主として、圧縮機２１と、四路切換弁２２と、室外熱交換器１２３と、膨張弁２４と、室外ファン２５と、デフロスト用流路機構１２６とを有している。尚、室外ユニット１０２の構成は、室外熱交換器１２３及びデフロスト用流路機構１２６の構成を除いて、第１実施形態の室外ユニット２の構成と同様であるため、ここでは、室外熱交換器１２３及びデフロスト用流路機構１２６の構成について、詳細に説明する。 (Indoor unit)
The indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 110. The indoor unit 4 mainly has an indoor heat exchanger 41. Note that the configuration of the indoor unit 4 is the same as the configuration of the indoor unit 4 of the first embodiment, and a description thereof will be omitted here.
(Outdoor unit)
The outdoor unit 102 is installed outside and constitutes a part of the refrigerant circuit 110. The outdoor unit 102 mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 123, an expansion valve 24, an outdoor fan 25, and a defrost channel mechanism 126. The configuration of the outdoor unit 102 is the same as the configuration of the outdoor unit 2 of the first embodiment except for the configuration of the outdoor heat exchanger 123 and the defrosting flow path mechanism 126. The configuration of the 123 and the defrost flow path mechanism 126 will be described in detail.
　室外熱交換器１２３は、冷房運転時には冷媒の放熱器として機能し、暖房運転時には冷媒の蒸発器として機能する熱交換器である。ここでは、室外熱交換器１２３として、伝熱管と多数のフィンとにより構成されたクロスフィン式のフィン・アンド・チューブ型熱交換器が採用されている。室外熱交換器１２３は、その液側が液冷媒管２７を介して膨張弁２４に接続されており、ガス側がガス冷媒管２８を介して四路切換弁２２に接続されている。
　より具体的には、室外熱交換器１２３は、第１実施形態の室外熱交換器２３と同様に、多数のフィン６１と、これらのフィン６１を板厚方向に貫通させた状態で取り付けられた多数の伝熱管６２とを有している（図２を参照）。この室外熱交換器１２３においては、図２２に示すように、伝熱管６１を上下方向に複数（ここでは、４つ）の系統に分けて、これらを相互に独立した第１熱交パス３１、第２熱交パス３２、第３熱交パス３３と、第１～第３熱交パス３１～３３に共通の過冷却パス３４としている。ここで、図２２は、室外熱交換器１２３及びその近傍の構造を模式的に示した図である。そして、第１～第３熱交パス３１～３３の液側端は、それぞれ第１～第３キャピラリチューブ６３ａ～６３ｃを介して冷媒分流器６４に接続されている。冷媒分流器６４は、第１～第３熱交パス３１～３３の液側端に接続された第１～第３キャピラリチューブ６３ａ～６３ｃを合流させる管部材であり、過冷却パス－熱交パス連絡管３５に接続されている。第１～第３熱交パス３１～３３のガス側端は、それぞれ第１～第３ヘッダー連絡管６５ａ～６５ｃを介してヘッダー６６に接続されている。ヘッダー６６は、第１～第３熱交パス３１～３３のガス側端に接続された第１～第３ヘッダー連絡管６５ａ～６５ｃを合流させる管部材であり、ガス冷媒管２８に接続されている。過冷却パス３４は、第１～第３熱交パス３１～３３の液側端に共通に接続されている。過冷却パス３４の液側端は、液冷媒管２７に接続されている。過冷却パス３４のガス側端は、過冷却パス－熱交パス連絡管３５に接続されている。このように、室外熱交換器１２３を構成する複数（ここでは、３つ）の熱交パス３１～３３は、冷媒分流器６４及びヘッダー６６を介して互いに並列に接続されている。また、室外熱交換器１２３を構成する過冷却パス３４は、熱交パス３１～３３の液側端に、冷媒分流器６４及び過冷却パス－熱交パス連絡管３５を介して接続されている。そして、冷房運転時には、すべての熱交パス３１～３３が冷媒の放熱器として機能し、過冷却パス３４が熱交パス３１～３３で放熱した冷媒の過冷却器として機能する。また、暖房運転時には、過冷却パス３４が、膨張弁２４を通過した後の中間圧状態の冷媒の放熱器として機能して、室外熱交換器１２３の最下部の着霜を防止し、すべての熱交パス３１～３３が冷媒の蒸発器として機能するようになっている。 The outdoor heat exchanger 123 is a heat exchanger that functions as a refrigerant radiator during cooling operation and functions as a refrigerant evaporator during heating operation. Here, as the outdoor heat exchanger 123, a cross fin type fin-and-tube heat exchanger constituted by a heat transfer tube and a large number of fins is employed. The outdoor heat exchanger 123 has a liquid side connected to the expansion valve 24 via a liquid refrigerant pipe 27 and a gas side connected to the four-way switching valve 22 via a gas refrigerant pipe 28.
More specifically, the outdoor heat exchanger 123 is attached in a state where a large number of fins 61 and these fins 61 are penetrated in the plate thickness direction, like the outdoor heat exchanger 23 of the first embodiment. It has a large number of heat transfer tubes 62 (see FIG. 2). In this outdoor heat exchanger 123, as shown in FIG. 22, the heat transfer tubes 61 are divided into a plurality of (here, four) systems in the vertical direction, and these are separated from each other in the first heat exchange path 31, The second heat exchange path 32, the third heat exchange path 33, and the supercooling path 34 common to the first to third heat exchange paths 31 to 33 are used. Here, FIG. 22 is a diagram schematically showing the outdoor heat exchanger 123 and the structure in the vicinity thereof. The liquid side ends of the first to third heat exchange paths 31 to 33 are connected to the refrigerant distributor 64 via the first to third capillary tubes 63a to 63c, respectively. The refrigerant flow divider 64 is a pipe member that joins the first to third capillary tubes 63a to 63c connected to the liquid side ends of the first to third heat exchange paths 31 to 33, and is a supercooling path-heat exchange path. It is connected to the communication pipe 35. The gas side ends of the first to third heat exchange paths 31 to 33 are connected to the header 66 via first to third header communication pipes 65a to 65c, respectively. The header 66 is a pipe member that joins the first to third header connecting pipes 65a to 65c connected to the gas side ends of the first to third heat exchange paths 31 to 33, and is connected to the gas refrigerant pipe 28. Yes. The supercooling path 34 is connected in common to the liquid side ends of the first to third heat exchange paths 31 to 33. The liquid side end of the supercooling path 34 is connected to the liquid refrigerant pipe 27. The gas side end of the supercooling path 34 is connected to a supercooling path-heat exchange path connecting pipe 35. As described above, the plurality of (here, three) heat exchange paths 31 to 33 constituting the outdoor heat exchanger 123 are connected in parallel to each other via the refrigerant flow divider 64 and the header 66. The subcooling path 34 constituting the outdoor heat exchanger 123 is connected to the liquid side ends of the heat exchange paths 31 to 33 via the refrigerant flow divider 64 and the supercooling path-heat exchange path connecting pipe 35. . During the cooling operation, all the heat exchange paths 31 to 33 function as a refrigerant radiator, and the supercooling path 34 functions as a refrigerant subcooler that radiates heat in the heat exchange paths 31 to 33. Further, during the heating operation, the supercooling path 34 functions as a radiator for the refrigerant in the intermediate pressure state after passing through the expansion valve 24 to prevent frosting at the bottom of the outdoor heat exchanger 123, and The heat exchange paths 31 to 33 function as a refrigerant evaporator.
　デフロスト用流路機構１２６は、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４を通過させた後に、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送るための機構である。このデフロスト用流路機構１２６は、後述の暖房デフロスト運転を行うために設けられている。この暖房デフロスト運転は、室外熱交換器１２３を構成する熱交パス３１～３３のうちの任意の熱交パスの除霜を行いつつ、室内熱交換器４１から室外熱交換器２３に送られる冷媒を蒸発させる運転である。デフロスト用流路機構１２６は、主として、熱交パス供給管７１と、複数（ここでは、３つ）の熱交パス分岐管７２ａ～７２ｃと、複数（ここでは、３つ）の分岐管側熱交パス選択弁７３ａ～７３ｃと、複数（ここでは、３つ）のヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とを有している。 The defrost flow path mechanism 126 passes a plurality of heat exchange paths without allowing the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 to flow into the refrigerant flow divider 64 after passing through the supercooling path 34. It is a mechanism for sending to the gas side end of the heat exchange path arbitrarily selected from 31 to 33. The defrost flow path mechanism 126 is provided to perform a heating defrost operation described later. In this heating defrost operation, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 while defrosting any of the heat exchange paths 31 to 33 constituting the outdoor heat exchanger 123. It is the operation which evaporates. The defrost flow path mechanism 126 mainly includes a heat exchange path supply pipe 71, a plurality (here, three) heat exchange path branch pipes 72a to 72c, and a plurality (here, three) branch pipe side heat. There are exchange path selection valves 73a to 73c, a plurality (three in this case) of header side heat exchange path selection valves 74a to 74c, and a branch pipe side selection valve 75.
　熱交パス供給管７１は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を、過冷却パス３４を通過させた後でかつ冷媒分流器６４に流入させる前に、過冷却パス－熱交パス連絡管３５から分岐するための冷媒管である。熱交パス供給管７１は、その一端が過冷却パス－熱交パス連絡管３５のうち過冷却パス３４のガス側端と冷媒分流器６４との間の部分に接続されており、他端が熱交パス分岐管７２ａ～７２ｃに接続されている。
　第１～第３熱交パス分岐管７２ａ～７２ｃは、熱交パス供給管７１を流れる冷媒を第１～第３熱交パス３１～３３のガス側端に供給するための冷媒管である。第１～第３熱交パス分岐管７２ａ～７２ｃは、それぞれ、その一端が熱交パス供給管７１に接続されており、他端が第１～第３ヘッダー連絡管６５ａ～６５ｃに接続されている。
　第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃは、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃとともに、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のいずれの熱交パスのガス側端に冷媒を送るかを選択するための電磁弁である。第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃは、それぞれ第１～第３熱交パス分岐管７２ａ～７２ｃに設けられている。そして、冷房運転時及び暖房運転時には、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止されるようになっている。また、暖房デフロスト運転時には、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃのうち除霜を行う熱交パスに対応する分岐管側熱交パス選択弁が開けられ、それ以外の熱交パスに対応する分岐管側熱交パス選択弁が閉止されるようになっている。 The heat exchange path supply pipe 71 passes the supercooling path − after the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 passes through the supercooling path 34 and before flowing into the refrigerant distributor 64. It is a refrigerant pipe for branching from the heat exchange path connecting pipe 35. One end of the heat exchange path supply pipe 71 is connected to a portion of the supercooling path-heat exchange path connecting pipe 35 between the gas side end of the supercooling path 34 and the refrigerant flow divider 64, and the other end. The heat exchange path branch pipes 72a to 72c are connected.
The first to third heat exchange path branch pipes 72a to 72c are refrigerant pipes for supplying the refrigerant flowing through the heat exchange path supply pipe 71 to the gas side ends of the first to third heat exchange paths 31 to 33. Each of the first to third heat exchange path branch pipes 72a to 72c has one end connected to the heat exchange path supply pipe 71 and the other end connected to the first to third header communication pipes 65a to 65c. Yes.
The first to third branch pipe side heat exchange path selection valves 73a to 73c, together with the first to third header side heat exchange path selection valves 74a to 74c, allow the refrigerant flowing through the heat exchange path supply pipe 71 to pass through the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to. The first to third branch pipe side heat exchange path selection valves 73a to 73c are provided in the first to third heat exchange path branch pipes 72a to 72c, respectively. During the cooling operation and the heating operation, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed. Further, during the heating defrost operation, the branch pipe side heat exchange path selection valve corresponding to the heat exchange path for defrosting among the first to third branch pipe side heat exchange path selection valves 73a to 73c is opened. The branch pipe side heat exchange path selection valve corresponding to the heat exchange path is closed.
　第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃは、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃとともに、熱交パス供給管７１を流れる冷媒を熱交パス３１～３３のいずれの熱交パスのガス側端に冷媒を送るかを選択するための電磁弁である。第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃは、それぞれ第１～第３ヘッダー連絡管６５ａ～６５ｃのうち第１～第３熱交パス分岐管７２ａ～７２ｃの他端が接続された位置とヘッダー６６との間の部分に設けられている。そして、冷房運転時及び暖房運転時には、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられるようになっている。また、暖房デフロスト運転時には、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃのうち除霜を行う熱交パスに対応するヘッダー側熱交パス選択弁が閉止され、それ以外の熱交パスに対応するヘッダー側熱交パス選択弁が開けられるようになっている。 The first to third header side heat exchange path selection valves 74a to 74c, together with the first to third branch pipe side heat exchange path selection valves 73a to 73c, transfer the refrigerant flowing through the heat exchange path supply pipe 71 to the heat exchange path 31 to 33 is an electromagnetic valve for selecting which of 33 heat exchange paths to send the refrigerant to. The first to third header side heat exchange path selection valves 74a to 74c are connected to the other ends of the first to third heat exchange path branch pipes 72a to 72c among the first to third header communication pipes 65a to 65c, respectively. It is provided in a portion between the position and the header 66. During the cooling operation and the heating operation, all of the first to third header side heat exchange path selection valves 74a to 74c are opened. In addition, during the heating defrost operation, the header side heat exchange path selection valve corresponding to the heat exchange path for defrosting is closed among the first to third header side heat exchange path selection valves 74a to 74c, and the other heat exchanges are performed. The header side heat exchange path selection valve corresponding to the path can be opened.
　分流管側選択弁７５は、室内熱交換器４１から室外熱交換器２３に送られる冷媒を、過冷却パス３４を通過させた後でかつ冷媒分流器６４に流入させる前に、過冷却パス－熱交パス連絡管３５から分岐するかどうかを選択するための電磁弁である。分流管側選択弁７５は、過冷却パス－熱交パス連絡管３５のうち熱交パス供給管７１が分岐された位置と冷媒分流器６４との間の部分に設けられている。そして、冷房運転時及び暖房運転時には、分流管側選択弁７５が開けられるようになっている。また、暖房デフロスト運転時には、分流管側選択弁７５が閉止されるようになっている。
　（動作）
　次に、上記の構成を有する空気調和装置１０１の動作について説明する。尚、以下の動作を行うために必要な各種機器の制御や各種処理等は、第１実施形態の空気調和装置１と同様に、制御部８によって行われる。 The shunt pipe side selection valve 75 is configured to pass the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 after passing through the supercooling path 34 and before flowing into the refrigerant flow divider 64. It is a solenoid valve for selecting whether or not to branch from the heat exchange path connecting pipe 35. The branch pipe side selection valve 75 is provided in a portion between the position where the heat exchange path supply pipe 71 is branched in the supercooling path-heat exchange path connecting pipe 35 and the refrigerant distributor 64. And the shunt pipe side selection valve 75 is opened at the time of air_conditionaing | cooling operation and heating operation. Further, during the heating defrost operation, the branch pipe side selection valve 75 is closed.
(Operation)
Next, operation | movement of the air conditioning apparatus 101 which has said structure is demonstrated. In addition, control of various apparatus required for performing the following operation | movement, various processes, etc. are performed by the control part 8 similarly to the air conditioning apparatus 1 of 1st Embodiment.
　空気調和装置１０１の運転としては、室内の冷房を行う冷房運転と、室内の暖房のみを行う暖房運転と、室外熱交換器２３の除霜を行いつつ室内の暖房を行う暖房デフロスト運転とがある。以下、各運転時の動作について、図２３、図６、図２４及び図２５を用いて説明する。ここで、図２３は、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図２４は、暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。図２５は、暖房デフロスト運転時の冷凍サイクルが図示された圧力－エンタルピ線図である。
　－冷房運転－
　冷房運転は、圧縮機２１、室外熱交換器１２３、室内熱交換器４１、圧縮機２１の順に冷媒を循環させる運転である。この冷房運転では、室外熱交換器１２３が冷媒の放熱器として機能し、かつ、室内熱交換器４１が冷媒の蒸発器として機能し、これにより、室内空気を冷却する。 The operation of the air conditioner 101 includes a cooling operation that cools the room, a heating operation that only heats the room, and a heating defrost operation that heats the room while defrosting the outdoor heat exchanger 23. . Hereafter, the operation | movement at each driving | operation is demonstrated using FIG.23, FIG.6, FIG.24 and FIG. Here, FIG. 23 is a diagram illustrating the flow of the refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 24 is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during heating / defrosting operation (when defrosting the first heat exchange path 31). FIG. 25 is a pressure-enthalpy diagram illustrating the refrigeration cycle during the heating defrost operation.
-Cooling operation-
The cooling operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the outdoor heat exchanger 123, the indoor heat exchanger 41, and the compressor 21. In this cooling operation, the outdoor heat exchanger 123 functions as a refrigerant radiator, and the indoor heat exchanger 41 functions as a refrigerant evaporator, thereby cooling indoor air.
　冷房運転においては、室外熱交換器１２３が冷媒の放熱器として機能し、かつ、室内熱交換器４１が冷媒の蒸発器として機能する状態（すなわち、図２１の四路切換弁２２の実線で示される状態）になるように、四路切換弁２２が切り換えられる。また、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止され、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられ、分流管側選択弁７５が開けられた状態になっている。すなわち、デフロスト用流路機構１２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃには、冷媒が流れない状態になっている。
　このような状態の冷媒回路１１０において、冷凍サイクルにおける低圧の冷媒は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、室外熱交換器１２３に送られる。そして、圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２、ガス冷媒管２８、ヘッダー６６、ヘッダー連絡管６５ａ～６５ｃ、及び、ヘッダー側熱交パス選択弁７４ａ～７４ｃを通じて、室外熱交換器１２３の熱交パス３１～３３のガス側端に送られる。そして、熱交パス３１～３３のガス側端に送られた高圧の冷媒は、熱交パス３１～３３において、室外ファン２５によって供給される室外空気と熱交換を行って放熱する。そして、熱交パス３１～３３において放熱した高圧の冷媒は、熱交パス３１～３３の液側端から、キャピラリチューブ６３ａ～６３ｃ、冷媒分流器６４、過冷却パス－熱交パス連絡管３５、及び、分流管側選択弁７５を通じて、室外熱交換器１２３の過冷却パス３４のガス側端に送られる。そして、過冷却パス３４のガス側端に送られた高圧の冷媒は、過冷却パス３４において、室外ファン２５によって供給される室外空気と熱交換を行ってさらに放熱する。そして、過冷却パス３４において過冷却された高圧の冷媒は、液冷媒管２７を通じて、膨張弁２４に送られる。膨張弁２４に送られた冷媒は、冷凍サイクルにおける低圧まで減圧される。膨張弁２４において減圧された低圧の冷媒は、液冷媒連絡管５を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた低圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って蒸発する。室内熱交換器４１において蒸発した低圧の冷媒は、ガス冷媒連絡管６及び四路切換弁２２を通じて、再び、圧縮機２１に吸入される。 In the cooling operation, the outdoor heat exchanger 123 functions as a refrigerant radiator and the indoor heat exchanger 41 functions as a refrigerant evaporator (that is, indicated by the solid line of the four-way switching valve 22 in FIG. 21). The four-way selector valve 22 is switched so that Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126.
In the refrigerant circuit 110 in such a state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 123 through the four-way switching valve 22. The high-pressure refrigerant discharged from the compressor 21 passes through the four-way switching valve 22, the gas refrigerant pipe 28, the header 66, the header communication pipes 65a to 65c, and the header side heat exchange path selection valves 74a to 74c. It is sent to the gas side ends of the heat exchange paths 31 to 33 of the heat exchanger 123. Then, the high-pressure refrigerant sent to the gas side ends of the heat exchange paths 31 to 33 performs heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33 to radiate heat. Then, the high-pressure refrigerant that has radiated heat in the heat exchange paths 31 to 33 flows from the liquid side ends of the heat exchange paths 31 to 33, capillary tubes 63a to 63c, refrigerant flow divider 64, supercooling path-heat exchange path connecting pipe 35, And, it is sent to the gas side end of the supercooling path 34 of the outdoor heat exchanger 123 through the branch pipe side selection valve 75. The high-pressure refrigerant sent to the gas side end of the supercooling path 34 further dissipates heat by exchanging heat with the outdoor air supplied by the outdoor fan 25 in the supercooling path 34. The high-pressure refrigerant supercooled in the supercooling path 34 is sent to the expansion valve 24 through the liquid refrigerant pipe 27. The refrigerant sent to the expansion valve 24 is depressurized to a low pressure in the refrigeration cycle. The low-pressure refrigerant decompressed by the expansion valve 24 is sent to the indoor heat exchanger 41 through the liquid refrigerant communication pipe 5. The low-pressure refrigerant sent to the indoor heat exchanger 41 evaporates by exchanging heat with indoor air in the indoor heat exchanger 41. The low-pressure refrigerant evaporated in the indoor heat exchanger 41 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6 and the four-way switching valve 22.
　－暖房運転－
　暖房運転は、圧縮機２１、室内熱交換器４１、室外熱交換器１２３、圧縮機２１の順に冷媒を循環させる運転である。この暖房運転では、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器１２３が冷媒の蒸発器として機能し、これにより、室内空気を加熱する。
　暖房運転においては、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器１２３が冷媒の蒸発器として機能する状態（すなわち、図２１及び図２３の四路切換弁２２の破線で示される状態）になるように、四路切換弁２２が切り換えられる。また、第１～第３分岐管側熱交パス選択弁７３ａ～７３ｃがすべて閉止され、第１～第３ヘッダー側熱交パス選択弁７４ａ～７４ｃがすべて開けられ、分流管側選択弁７５が開けられた状態になっている。すなわち、デフロスト用流路機構１２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃには、冷媒が流れない状態になっている。 -Heating operation-
The heating operation is an operation in which the refrigerant is circulated in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 123, and the compressor 21. In this heating operation, the indoor heat exchanger 41 functions as a refrigerant radiator, and the outdoor heat exchanger 123 functions as a refrigerant evaporator, thereby heating indoor air.
In the heating operation, the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 123 functions as a refrigerant evaporator (that is, the four-way switching valve 22 in FIGS. 21 and 23). The four-way switching valve 22 is switched so as to be in a state indicated by a broken line. Further, the first to third branch pipe side heat exchange path selection valves 73a to 73c are all closed, the first to third header side heat exchange path selection valves 74a to 74c are all opened, and the branch pipe side selection valve 75 is opened. It is in an open state. That is, the refrigerant does not flow through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126.
　このような状態の冷媒回路１１０において、冷凍サイクルにおける低圧の冷媒は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、ガス冷媒連絡管６を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた高圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って放熱する。室内熱交換器４１において放熱した高圧の冷媒は、液冷媒連絡管５を通じて、膨張弁２４に送られて、冷凍サイクルにおける中間圧まで減圧される。膨張弁２４において減圧された中間圧の冷媒は、室外熱交換器１２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７を通じて、室外熱交換器１２３の過冷却パス３４の液側端に送られる。そして、過冷却パス３４の液側端に送られた中間圧の冷媒は、過冷却パス３４において、室外ファン２５によって供給される室外空気と熱交換を行って放熱し、これにより、室外熱交換器１２３の最下部における着霜を防止する。そして、過冷却パス３４において放熱した低圧の冷媒は、過冷却パス３４のガス側端から、過冷却パス－熱交パス連絡管３５、分流管側選択弁７５、冷媒分流器６４、及び、キャピラリチューブ６３ａ～６３ｃを通じて、室外熱交換器２３の熱交パス３１～３３の液側端に送られる。そして、熱交パス３１～３３の液側端に送られた低圧の冷媒は、熱交パス３１～３３において、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、熱交パス３１～３３において蒸発した低圧の冷媒は、熱交パス３１～３３のガス側端から、ヘッダー連絡管６５ａ～６５ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。 In the refrigerant circuit 110 in such a state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21 and is discharged after being compressed to a high pressure in the refrigeration cycle. The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22. The high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41. The high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication pipe 5 and reduced to an intermediate pressure in the refrigeration cycle. The intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123 through the liquid refrigerant pipe 27. The intermediate-pressure refrigerant sent to the liquid side end of the supercooling path 34 radiates heat by exchanging heat with the outdoor air supplied by the outdoor fan 25 in the supercooling path 34, thereby performing outdoor heat exchange. Frost formation at the bottom of the vessel 123 is prevented. Then, the low-pressure refrigerant radiated in the supercooling path 34 is supplied from the gas side end of the supercooling path 34 to the supercooling path-heat exchange path connecting pipe 35, the diversion pipe side selection valve 75, the refrigerant flow divider 64, and the capillary It is sent to the liquid side ends of the heat exchange paths 31 to 33 of the outdoor heat exchanger 23 through the tubes 63a to 63c. The low-pressure refrigerant sent to the liquid side ends of the heat exchange paths 31 to 33 evaporates through heat exchange with the outdoor air supplied by the outdoor fan 25 in the heat exchange paths 31 to 33. The low-pressure refrigerant evaporated in the heat exchange paths 31 to 33 flows from the gas side ends of the heat exchange paths 31 to 33 to the header communication pipes 65a to 65c, the header side heat exchange path selection valves 74a to 74c, the header 66, and the gas. The refrigerant is again sucked into the compressor 21 through the refrigerant pipe 28 and the four-way switching valve 22.
　－暖房デフロスト運転－
　暖房デフロスト運転は、暖房運転時と同様に、圧縮機２１、室内熱交換器４１、室外熱交換器１２３、圧縮機２１の順に冷媒を循環させる運転を行いつつ、デフロスト用流路機構１２６によって、室外熱交換器１２３の除霜を行う運転である。この暖房デフロスト運転では、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器１２３の第１～第３熱交パス３１～３３のうちのいずれか１つが冷媒の放熱器として機能し、残りの熱交パス３１～３３が冷媒の蒸発器として機能する。これにより、室外熱交換器１２３の第１～第３熱交パス３１～３３の除霜を順次行いつつ、室内空気を加熱する。
　暖房デフロスト運転における四路切換弁２２の切り換え状態は、暖房運転時と同様である。すなわち、四路切換弁２２は、室内熱交換器４１が冷媒の放熱器として機能し、かつ、室外熱交換器１２３が冷媒の蒸発器として機能する状態（すなわち、図２１及び図２４の四路切換弁２２の破線で示される状態）になっている。また、室外熱交換器１２３の第１～第３熱交パス３１～３３の除霜を順次行うために、選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５が、冷房運転時及び暖房運転時と異なる開閉状態に切り換えられる。すなわち、暖房デフロスト運転においては、デフロスト用流路機構１２６の熱交パス供給管７１及び第１～第３熱交パス分岐管７２ａ～７２ｃに、冷媒が流れる状態となる。以下、暖房デフロスト運転時の動作について、暖房デフロスト運転の開始から終了までの手順も含めて、詳細に説明する。 -Heating defrost operation-
As in the heating operation, the heating defrost operation is performed by circulating the refrigerant in the order of the compressor 21, the indoor heat exchanger 41, the outdoor heat exchanger 123, and the compressor 21, In this operation, the outdoor heat exchanger 123 is defrosted. In this heating defrost operation, the indoor heat exchanger 41 functions as a refrigerant radiator, and any one of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 is a refrigerant radiator. The remaining heat exchange paths 31 to 33 function as a refrigerant evaporator. Accordingly, the indoor air is heated while the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 are sequentially defrosted.
The switching state of the four-way switching valve 22 in the heating defrost operation is the same as in the heating operation. That is, the four-way switching valve 22 is in a state where the indoor heat exchanger 41 functions as a refrigerant radiator and the outdoor heat exchanger 123 functions as a refrigerant evaporator (that is, the four-way valves in FIGS. 21 and 24). The state shown by the broken line of the switching valve 22). Further, since the defrosting of the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 is sequentially performed, the selection valves 73a to 73c, 74a to 74c, and 75 are different from those during the cooling operation and the heating operation. Switch to open / closed state. That is, in the heating defrost operation, the refrigerant flows through the heat exchange path supply pipe 71 and the first to third heat exchange path branch pipes 72a to 72c of the defrost flow path mechanism 126. Hereinafter, the operation during the heating defrost operation will be described in detail including the procedure from the start to the end of the heating defrost operation.
　まず、ステップＳ１において、暖房運転によって室外熱交換器１２３における着霜量が増加し、除霜が必要になったかどうかを判定する。尚、この除霜が必要かどうかの判定は、第１実施形態の暖房デフロスト運転のステップＳ１と同様であるため、ここでは説明を省略する。
　次に、ステップＳ２～Ｓ７において、室外熱交換器１２３の第１～第３熱交パス３１～３３の除霜を順次行う。尚、第１～第３熱交パス３１～３３の除霜は、基本的に任意に選択してもよいが、除霜によって発生するドレン水をユニットケーシング５１の底板５２まで排水する流れを考慮すると、室外熱交換器１２３の上部から下部に向けて行うことが好ましい。このため、ここでは、第１熱交パス３１、第２熱交パス３２、第３熱交パス３３の順に除霜を行うものとする。 First, in step S1, it is determined whether or not the amount of frost formation in the outdoor heat exchanger 123 has increased due to the heating operation, and defrosting is necessary. In addition, since determination of whether this defrost is required is the same as that of step S1 of the heating defrost operation of 1st Embodiment, description is abbreviate | omitted here.
Next, in steps S2 to S7, the first to third heat exchange paths 31 to 33 of the outdoor heat exchanger 123 are sequentially defrosted. The defrosting of the first to third heat exchange paths 31 to 33 may basically be arbitrarily selected, but the flow of drain water generated by the defrosting to the bottom plate 52 of the unit casing 51 is considered. Then, it is preferable to carry out from the upper part of the outdoor heat exchanger 123 toward the lower part. For this reason, here, defrosting shall be performed in the order of the first heat exchange path 31, the second heat exchange path 32, and the third heat exchange path 33.
　第１熱交パス３１の除霜（ステップＳ２）は、デフロスト用流路機構１２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第１分岐管側熱交パス選択弁７３ａが開けられ、第２及び第３分岐管側熱交パス選択弁７３ｂ、７３ｃが閉止され、第１ヘッダー側熱交パス選択弁７４ａが閉止され、第２及び第３ヘッダー側熱交パス選択弁７４ｂ、７４ｃが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第１熱交パス３１の除霜の開始前までは暖房運転が行われていることから、第１分岐管側熱交パス選択弁７３ａを開け、第１ヘッダー側熱交パス選択弁７４ａを閉止し、分流管側選択弁７５を閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構１２６の熱交パス供給管７１及び第１熱交パス分岐管７２ａに冷媒が流れる状態となる。 The defrosting (step S2) of the first heat exchange path 31 is performed by switching the open / close states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 126. Specifically, the first branch pipe side heat exchange path selection valve 73a is opened, the second and third branch pipe side heat exchange path selection valves 73b and 73c are closed, and the first header side heat exchange path selection valve 74a is closed. Is closed, the second and third header side heat exchange path selection valves 74b and 74c are opened, and the flow dividing pipe side selection valve 75 is switched to a closed state. Here, since the heating operation is performed before the defrosting of the first heat exchange path 31 is started, the first branch pipe side heat exchange path selection valve 73a is opened and the first header side heat exchange path is opened. A switching operation for closing the selection valve 74a and closing the branch pipe side selection valve 75 is performed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the first heat exchange path branch pipe 72a of the defrost flow path mechanism 126.
　このような状態の冷媒回路１１０において、冷凍サイクルにおける低圧の冷媒（図２４及び図２５の点Ａを参照）は、圧縮機２１に吸入され、冷凍サイクルにおける高圧まで圧縮された後に吐出される（図２４及び図２５の点Ｂを参照）。圧縮機２１から吐出された高圧の冷媒は、四路切換弁２２を通じて、ガス冷媒連絡管６を通じて、室内熱交換器４１に送られる。室内熱交換器４１に送られた高圧の冷媒は、室内熱交換器４１において、室内空気と熱交換を行って放熱する（図２４及び図２５の点Ｃを参照）。ここまでは、暖房運転時と同様である。室内熱交換器４１において放熱した高圧の冷媒は、液冷媒連絡管５を通じて、膨張弁２４に送られて、冷凍サイクルにおける高圧と低圧との間の圧力（以下、中間圧とする）まで減圧される（図２４及び図２５の点Ｄを参照）。膨張弁２４において減圧された中間圧の冷媒は、室外熱交換器１２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から室外熱交換器１２３の過冷却パス３４の液側端に送られる。そして、過冷却パス３４の液側端に送られた中間圧の冷媒は、過冷却パス３４において、第１熱交パス３１の除霜によって溶けて室外熱交換器１２３の最下部まで流下したドレン水を加熱し、これにより、ドレンパンとして機能する底板５２の温度が低いことに起因してドレン水が再凍結することを防止している（図２４及び図２５の点Ｄ’を参照）。これにより、室外熱交換器１２３の過冷却パス３４におけるドレン水の再凍結防止が行われる。そして、過冷却パス３４を通過した中間圧の冷媒は、過冷却パス３４のガス側端から、過冷却パス－熱交パス連絡管３５を通じて、熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第１熱交パス分岐管７２ａ、第１分岐管側熱交パス選択弁７３ａ、及び、第１ヘッダー連絡管６５ａを通じて、室外熱交換器１２３の第１熱交パス３１のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器１２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第１熱交パス３１のガス側端に送られることになる。そして、第１熱交パス３１のガス側端に送られた中間圧の冷媒は、第１熱交パス３１のガス側端から液側端に向かって第１熱交パス３１内を通過し、室外熱交換器１２３の第１熱交パス３１に付着した霜を溶かす（図２４及び図２５の点Ｅを参照）。これにより、室外熱交換器２３の第１熱交パス３１の除霜が行われる。そして、第１熱交パス３１を通過した中間圧の冷媒は、第１熱交パス３１の液側端から、第１キャピラリチューブ６３ａを通じて、冷媒分流器６４に送られる。このとき、第１キャピラリチューブ６３ａは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧（すなわち、図２４及び図２５の点Ｅにおける圧力）と低圧の間の圧力まで減圧されることになる（図２４及び図２５の点Ｆを参照）。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第２及び第３キャピラリチューブ６３ｂ、６３ｃに分岐されて、第２及び第３熱交パス３２、３３の液側端に送られる。このとき、冷媒は、第２及び第３キャピラリチューブ６３ｂ、６３ｃを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる（図２４及び図２５の点Ｇを参照）。そして、第２及び第３熱交パス３２、３３の液側端に送られた低圧の冷媒は、第２及び第３熱交パス３２、３３の液側端からガス側端に向かって第２及び第３熱交パス３２、３３内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する（図２４及び図２５の点Ａを参照）。そして、第２及び第３熱交パス３２、３３において蒸発した低圧の冷媒は、第２及び第３熱交パス３２、３３のガス側端から、第２及び第３ヘッダー連絡管６５ｂ、６５ｃ、第２及び第３ヘッダー側熱交パス選択弁７４ｂ、７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第１熱交パス３１の除霜が開始される。そして、第１熱交パス３１の除霜は、第１熱交パス３１の除霜が完了するまで行われる（ステップＳ３）。 In the refrigerant circuit 110 in such a state, the low-pressure refrigerant (see point A in FIGS. 24 and 25) in the refrigeration cycle is sucked into the compressor 21 and discharged after being compressed to a high pressure in the refrigeration cycle ( (See point B in FIGS. 24 and 25). The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the gas refrigerant communication pipe 6 through the four-way switching valve 22. The high-pressure refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air in the indoor heat exchanger 41 (see point C in FIGS. 24 and 25). Up to this point, it is the same as in the heating operation. The high-pressure refrigerant that has radiated heat in the indoor heat exchanger 41 is sent to the expansion valve 24 through the liquid refrigerant communication tube 5 and is reduced to a pressure between the high pressure and the low pressure (hereinafter referred to as intermediate pressure) in the refrigeration cycle. (See point D in FIGS. 24 and 25). The intermediate-pressure refrigerant decompressed by the expansion valve 24 is sent to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123. Then, the intermediate-pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the first heat exchange path 31 in the supercooling path 34 and flows down to the bottom of the outdoor heat exchanger 123. Water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan (see point D ′ in FIGS. 24 and 25). Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed. The intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35. Then, the intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the first heat exchange path branch pipe 72a, the first branch pipe side heat exchange path selection valve 73a, and the first header communication pipe 65a. It is sent to the gas side end of the first heat exchange path 31 of the heat exchanger 123. Thus, all the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 is sent to the gas side end of the first heat exchange path 31 without flowing into the refrigerant flow divider 64. The intermediate-pressure refrigerant sent to the gas side end of the first heat exchange path 31 passes through the first heat exchange path 31 from the gas side end of the first heat exchange path 31 toward the liquid side end, Frost adhering to the first heat exchange path 31 of the outdoor heat exchanger 123 is melted (see point E in FIGS. 24 and 25). Thereby, defrosting of the 1st heat exchange path 31 of the outdoor heat exchanger 23 is performed. The intermediate-pressure refrigerant that has passed through the first heat exchange path 31 is sent from the liquid side end of the first heat exchange path 31 to the refrigerant flow divider 64 through the first capillary tube 63a. At this time, the first capillary tube 63a flows an intermediate-pressure refrigerant having a larger flow rate than that during the cooling operation or the heating operation. Therefore, the first capillary tube 63a has a pressure loss as compared with the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure in the refrigeration cycle (that is, the pressure at point E in FIGS. 24 and 25) and the low pressure (see point F in FIGS. 24 and 25). The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the second and third capillary tubes 63b, because the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the second and third heat exchange paths 32 and 33. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the second and third capillary tubes 63b and 63c (see point G in FIGS. 24 and 25). The low-pressure refrigerant sent to the liquid side ends of the second and third heat exchange paths 32, 33 is second from the liquid side ends of the second and third heat exchange paths 32, 33 toward the gas side ends. Then, it passes through the third heat exchange paths 32 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25 (see point A in FIGS. 24 and 25). The low-pressure refrigerant evaporated in the second and third heat exchange paths 32 and 33 is supplied from the gas side ends of the second and third heat exchange paths 32 and 33 to the second and third header communication pipes 65b, 65c, The air is again sucked into the compressor 21 through the second and third header side heat exchange path selection valves 74b and 74c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the first heat exchange path 31 is started while continuing the indoor heating. And defrosting of the 1st heat exchange path 31 is performed until defrosting of the 1st heat exchange path 31 is completed (step S3).
　第２熱交パス３２の除霜（ステップＳ４）は、第１熱交パス３１と同様に、デフロスト用流路機構１２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第２分岐管側熱交パス選択弁７３ｂが開けられ、第１及び第３分岐管側熱交パス選択弁７３ａ、７３ｃが閉止され、第２ヘッダー側熱交パス選択弁７４ｂが閉止され、第１及び第３ヘッダー側熱交パス選択弁７４ａ、７４ｃが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第２熱交パス３２の除霜の開始前までは第１熱交パス３１の除霜が行われていることから、第２分岐管側熱交パス選択弁７３ｂを開け、第１分岐管側熱交パス選択弁７３ａを閉止し、第１ヘッダー側熱交パス選択弁７４ａを開け、第２ヘッダー側熱交パス選択弁７４ｂを閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構１２６の熱交パス供給管７１及び第２熱交パス分岐管７２ｂに冷媒が流れる状態となる。 The defrosting (step S4) of the second heat exchange path 32 is performed by switching the open / closed states of the selection valves 73a to 73c, 74a to 74c, 75 of the defrost flow path mechanism 126 in the same manner as the first heat exchange path 31. Done. Specifically, the second branch pipe side heat exchange path selection valve 73b is opened, the first and third branch pipe side heat exchange path selection valves 73a and 73c are closed, and the second header side heat exchange path selection valve 74b. Is closed, the first and third header side heat exchange path selection valves 74a and 74c are opened, and the branch pipe side selection valve 75 is switched to a closed state. Here, since the defrosting of the first heat exchange path 31 is performed before the start of the defrosting of the second heat exchange path 32, the second branch pipe side heat exchange path selection valve 73b is opened, A switching operation is performed in which the first branch pipe side heat exchange path selection valve 73a is closed, the first header side heat exchange path selection valve 74a is opened, and the second header side heat exchange path selection valve 74b is closed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the second heat exchange path branch pipe 72b of the defrost flow path mechanism 126.
　このような状態の冷媒回路１１０において、冷凍サイクルにおける低圧の冷媒は、第１熱交パス３１の除霜時と同様に、圧縮機２１において冷凍サイクルにおける高圧まで圧縮され、室内熱交換器４１において室内空気と熱交換を行って放熱し、膨張弁２４において冷凍サイクルにおける中間圧まで減圧され、室外熱交換器１２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から室外熱交換器１２３の過冷却パス３４の液側端に送られる。そして、過冷却パス３４の液側端に送られた中間圧の冷媒は、過冷却パス３４において、第２熱交パス３２の除霜によって溶けて室外熱交換器１２３の最下部まで流下したドレン水を加熱し、これにより、ドレンパンとして機能する底板５２の温度が低いことに起因してドレン水が再凍結することを防止している。これにより、室外熱交換器１２３の過冷却パス３４におけるドレン水の再凍結防止が行われる。そして、過冷却パス３４を通過した中間圧の冷媒は、過冷却パス３４のガス側端から、過冷却パス－熱交パス連絡管３５を通じて、熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第２熱交パス分岐管７２ｂ、第２分岐管側熱交パス選択弁７３ｂ、及び、第２ヘッダー連絡管６５ｂを通じて、室外熱交換器１２３の第２熱交パス３２のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器１２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第２熱交パス３２のガス側端に送られることになる。そして、第２熱交パス３２のガス側端に送られた中間圧の冷媒は、第２熱交パス３２のガス側端から液側端に向かって第２熱交パス３２内を通過し、室外熱交換器１２３の第２熱交パス３２に付着した霜を溶かす。これにより、室外熱交換器１２３の第２熱交パス３２の除霜が行われる。そして、第２熱交パス３２を通過した中間圧の冷媒は、第２熱交パス３２の液側端から、第２キャピラリチューブ６３ｂを通じて、冷媒分流器６４に送られる。このとき、第２キャピラリチューブ６３ｂは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧と低圧の間の圧力まで減圧されることになる。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第１及び第３キャピラリチューブ６３ａ、６３ｃに分岐されて、第１及び第３熱交パス３１、３３の液側端に送られる。このとき、冷媒は、第１及び第３キャピラリチューブ６３ａ、６３ｃを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる。そして、第１及び第３熱交パス３１、３３の液側端に送られた低圧の冷媒は、第１及び第３熱交パス３１、３３の液側端からガス側端に向かって第１及び第３熱交パス３１、３３内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、第１及び第３熱交パス３１、３３において蒸発した低圧の冷媒は、第１及び第３熱交パス３１、３３のガス側端から、第１及び第３ヘッダー連絡管６５ａ、６５ｃ、第１及び第３ヘッダー側熱交パス選択弁７４ａ、７４ｃ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第２熱交パス３２の除霜が開始される。そして、第２熱交パス３２の除霜は、第２熱交パス３２の除霜が完了するまで行われる（ステップＳ５）。 In the refrigerant circuit 110 in such a state, the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same manner as in the defrosting of the first heat exchange path 31, and in the indoor heat exchanger 41. Heat is exchanged with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends it to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the second heat exchange path 32 in the supercooling path 34 and flows down to the bottom of the outdoor heat exchanger 123. The water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan. Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed. The intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35. The intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the second heat exchange path branch pipe 72b, the second branch pipe side heat exchange path selection valve 73b, and the second header communication pipe 65b. It is sent to the gas side end of the second heat exchange path 32 of the heat exchanger 123. Thus, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 is all sent to the gas side end of the second heat exchange path 32 without flowing into the refrigerant flow divider 64. Then, the intermediate-pressure refrigerant sent to the gas side end of the second heat exchange path 32 passes through the second heat exchange path 32 from the gas side end of the second heat exchange path 32 toward the liquid side end, The frost attached to the second heat exchange path 32 of the outdoor heat exchanger 123 is melted. Thereby, defrosting of the 2nd heat exchange path 32 of the outdoor heat exchanger 123 is performed. The intermediate-pressure refrigerant that has passed through the second heat exchange path 32 is sent from the liquid side end of the second heat exchange path 32 to the refrigerant flow divider 64 through the second capillary tube 63b. At this time, the second capillary tube 63b has a flow rate of intermediate pressure refrigerant that is larger than that during cooling operation or heating operation. Therefore, the second capillary tube 63b has a pressure loss as compared with the case where the refrigerant flows during cooling operation or heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle. The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and third capillary tubes 63a, since the flow dividing pipe side selection valve 75 is closed. Branched to 63c and sent to the liquid side ends of the first and third heat exchange paths 31, 33. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and third capillary tubes 63a and 63c. The low-pressure refrigerant sent to the liquid side ends of the first and third heat exchange paths 31 and 33 is first from the liquid side ends of the first and third heat exchange paths 31 and 33 toward the gas side end. And passes through the third heat exchange paths 31 and 33 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. Then, the low-pressure refrigerant evaporated in the first and third heat exchange paths 31 and 33 flows from the gas side ends of the first and third heat exchange paths 31 and 33 to the first and third header communication pipes 65a and 65c, The air is again sucked into the compressor 21 through the first and third header side heat exchange path selection valves 74 a and 74 c, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the second heat exchange path 32 is started while continuing the indoor heating. And the defrosting of the 2nd heat exchange path 32 is performed until the defrosting of the 2nd heat exchange path 32 is completed (step S5).
　第３熱交パス３３の除霜（ステップＳ６）は、第１及び第２熱交パス３１、３２と同様に、デフロスト用流路機構１２６の選択弁７３ａ～７３ｃ、７４ａ～７４ｃ、７５の開閉状態を切り換えることによって行われる。具体的には、第３分岐管側熱交パス選択弁７３ｃが開けられ、第１及び第２分岐管側熱交パス選択弁７３ａ、７３ｂが閉止され、第３ヘッダー側熱交パス選択弁７４ｃが閉止され、第１及び第２ヘッダー側熱交パス選択弁７４ａ、７４ｂが開けられ、分流管側選択弁７５が閉止された状態に切り換えられる。尚、ここでは、第３熱交パス３３の除霜の開始前までは第２熱交パス３２の除霜が行われていることから、第３分岐管側熱交パス選択弁７３ｃを開け、第２分岐管側熱交パス選択弁７３ｂを閉止し、第２ヘッダー側熱交パス選択弁７４ｂを開け、第３ヘッダー側熱交パス選択弁７４ｃを閉止する切り換え動作が行われることになる。これにより、デフロスト用流路機構１２６の熱交パス供給管７１及び第３熱交パス分岐管７２ｃに冷媒が流れる状態となる。 The defrosting (step S6) of the third heat exchange path 33 is performed by opening and closing the selection valves 73a to 73c, 74a to 74c, and 75 of the defrost flow path mechanism 126, similarly to the first and second heat exchange paths 31 and 32. This is done by switching the state. Specifically, the third branch pipe side heat exchange path selection valve 73c is opened, the first and second branch pipe side heat exchange path selection valves 73a and 73b are closed, and the third header side heat exchange path selection valve 74c is closed. Is closed, the first and second header side heat exchange path selection valves 74a and 74b are opened, and the branch pipe side selection valve 75 is switched to a closed state. Here, since the defrosting of the second heat exchange path 32 is performed before the start of the defrosting of the third heat exchange path 33, the third branch pipe side heat exchange path selection valve 73c is opened, A switching operation is performed in which the second branch pipe side heat exchange path selection valve 73b is closed, the second header side heat exchange path selection valve 74b is opened, and the third header side heat exchange path selection valve 74c is closed. As a result, the refrigerant flows into the heat exchange path supply pipe 71 and the third heat exchange path branch pipe 72c of the defrost flow path mechanism 126.
　このような状態の冷媒回路１１０において、冷凍サイクルにおける低圧の冷媒は、第１及び第２熱交パス３１、３２の除霜時と同様に、圧縮機２１において冷凍サイクルにおける高圧まで圧縮され、室内熱交換器４１において室内空気と熱交換を行って放熱し、膨張弁２４において冷凍サイクルにおける中間圧まで減圧され、室外熱交換器１２３に送られる。そして、膨張弁２４において減圧された中間圧の冷媒は、液冷媒管２７から室外熱交換器１２３の過冷却パス３４の液側端に送られる。そして、過冷却パス３４の液側端に送られた中間圧の冷媒は、過冷却パス３４において、第２熱交パス３３の除霜によって溶けて室外熱交換器１２３の最下部まで流下したドレン水を加熱し、これにより、ドレンパンとして機能する底板５２の温度が低いことに起因してドレン水が再凍結することを防止している。これにより、室外熱交換器１２３の過冷却パス３４におけるドレン水の再凍結防止が行われる。そして、過冷却パス３４を通過した中間圧の冷媒は、過冷却パス３４のガス側端から、過冷却パス－熱交パス連絡管３５を通じて、熱交パス供給管７１に送られる。そして、熱交パス供給管７１に送られた中間圧の冷媒は、第３熱交パス分岐管７２ｃ、第３分岐管側熱交パス選択弁７３ｃ、及び、第３ヘッダー連絡管６５ｃを通じて、室外熱交換器２３の第３熱交パス３３のガス側端に送られる。このように、室内熱交換器４１から室外熱交換器２３に送られる冷媒は、冷媒分流器６４に流入することなく、すべて第３熱交パス３３のガス側端に送られることになる。そして、第３熱交パス３３のガス側端に送られた中間圧の冷媒は、第３熱交パス３３のガス側端から液側端に向かって第３熱交パス３３内を通過し、室外熱交換器１２３の第３熱交パス３３に付着した霜を溶かす。これにより、室外熱交換器１２３の第３熱交パス３３の除霜が行われる。そして、第３熱交パス３３を通過した中間圧の冷媒は、第３熱交パス３３の液側端から、第３キャピラリチューブ６３ｃを通じて、冷媒分流器６４に送られる。このとき、第３キャピラリチューブ６３ｃは、冷房運転時や暖房運転時に比べて流量の大きい中間圧の冷媒が流れることになるため、冷房運転時や暖房運転時に冷媒が流れる場合に比べて圧力損失が大きく、冷凍サイクルにおける中間圧と低圧の間の圧力まで減圧されることになる。そして、冷媒分流器６４に送られた低圧の冷媒は、分流管側選択弁７５が閉止しているため、冷媒分流器６４内を折り返すように通過して、第１及び第２キャピラリチューブ６３ａ、６３ｂに分岐されて、第１及び第２熱交パス３１、３２の液側端に送られる。このとき、冷媒は、第１及び第２キャピラリチューブ６３ａ、６３ｂを通過することによって、冷凍サイクルにおける低圧まで減圧されることになる。そして、第１及び第２熱交パス３１、３２の液側端に送られた低圧の冷媒は、第１及び第２熱交パス３１、３２の液側端からガス側端に向かって第１及び第２熱交パス３１、３２内を通過し、室外ファン２５によって供給される室外空気と熱交換を行って蒸発する。そして、第１及び第２熱交パス３１、３２において蒸発した低圧の冷媒は、第１及び第２熱交パス３１、３２のガス側端から、第１及び第２ヘッダー連絡管６５ａ、６５ｂ、第１及び第２ヘッダー側熱交パス選択弁７４ａ、７４ｂ、ヘッダー６６、ガス冷媒管２８、及び、四路切換弁２２を通じて、再び、圧縮機２１に吸入される。このようにして、室内の暖房を継続しつつ、第３熱交パス３３の除霜が開始される。そして、第３熱交パス３３の除霜は、第２熱交パス３３の除霜が完了するまで行われる（ステップＳ７）。 In the refrigerant circuit 110 in such a state, the low-pressure refrigerant in the refrigeration cycle is compressed to the high pressure in the refrigeration cycle in the compressor 21 in the same way as when the first and second heat exchange paths 31 and 32 are defrosted. The heat exchanger 41 performs heat exchange with room air to dissipate heat, and the expansion valve 24 reduces the pressure to an intermediate pressure in the refrigeration cycle and sends the heat to the outdoor heat exchanger 123. Then, the intermediate pressure refrigerant decompressed in the expansion valve 24 is sent from the liquid refrigerant pipe 27 to the liquid side end of the supercooling path 34 of the outdoor heat exchanger 123. The intermediate pressure refrigerant sent to the liquid side end of the supercooling path 34 is melted by the defrosting of the second heat exchange path 33 in the supercooling path 34 and flows down to the lowermost part of the outdoor heat exchanger 123. The water is heated, thereby preventing the drain water from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan. Thereby, refreezing prevention of drain water in the supercooling path 34 of the outdoor heat exchanger 123 is performed. The intermediate-pressure refrigerant that has passed through the supercooling path 34 is sent from the gas side end of the supercooling path 34 to the heat exchange path supply pipe 71 through the supercooling path-heat exchange path connecting pipe 35. The intermediate-pressure refrigerant sent to the heat exchange path supply pipe 71 passes through the third heat exchange path branch pipe 72c, the third branch pipe side heat exchange path selection valve 73c, and the third header communication pipe 65c. It is sent to the gas side end of the third heat exchange path 33 of the heat exchanger 23. Thus, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 is all sent to the gas side end of the third heat exchange path 33 without flowing into the refrigerant flow divider 64. The intermediate pressure refrigerant sent to the gas side end of the third heat exchange path 33 passes through the third heat exchange path 33 from the gas side end of the third heat exchange path 33 toward the liquid side end, The frost attached to the third heat exchange path 33 of the outdoor heat exchanger 123 is melted. Thereby, defrosting of the 3rd heat exchange path 33 of the outdoor heat exchanger 123 is performed. Then, the intermediate-pressure refrigerant that has passed through the third heat exchange path 33 is sent from the liquid side end of the third heat exchange path 33 to the refrigerant flow divider 64 through the third capillary tube 63c. At this time, in the third capillary tube 63c, an intermediate pressure refrigerant having a larger flow rate than in the cooling operation or the heating operation flows, so that the pressure loss is smaller than that in the case where the refrigerant flows during the cooling operation or the heating operation. It is greatly reduced to a pressure between the intermediate pressure and the low pressure in the refrigeration cycle. The low-pressure refrigerant sent to the refrigerant flow divider 64 passes through the refrigerant flow divider 64 so that the first and second capillary tubes 63a, because the flow dividing pipe side selection valve 75 is closed. Branched to 63 b and sent to the liquid side ends of the first and second heat exchange paths 31 and 32. At this time, the refrigerant is depressurized to a low pressure in the refrigeration cycle by passing through the first and second capillary tubes 63a and 63b. The low-pressure refrigerant sent to the liquid side ends of the first and second heat exchange paths 31 and 32 is first from the liquid side ends of the first and second heat exchange paths 31 and 32 toward the gas side ends. Then, it passes through the second heat exchange paths 31 and 32 and evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 25. The low-pressure refrigerant evaporated in the first and second heat exchange paths 31 and 32 flows from the gas side ends of the first and second heat exchange paths 31 and 32 to the first and second header communication pipes 65a and 65b, The air is again sucked into the compressor 21 through the first and second header side heat exchange path selection valves 74a and 74b, the header 66, the gas refrigerant pipe 28, and the four-way switching valve 22. In this way, defrosting of the third heat exchange path 33 is started while continuing the indoor heating. And the defrosting of the 3rd heat exchange path 33 is performed until the defrosting of the 2nd heat exchange path 33 is completed (step S7).
　そして、上記のステップＳ２～Ｓ７の処理によって室外熱交換器１２３のすべての熱交パス３１～３３の除霜が完了した後に、暖房運転に復帰する（ステップＳ８）。
　以上のように、デフロスト用流路機構１２６によって、熱交パス３１～３３のうちの任意の熱交パスの除霜を行いつつ、室内熱交換器４１から室外熱交換器２３に送られる冷媒を蒸発させる暖房デフロスト運転を行っている。そして、この暖房デフロスト運転を複数の熱交パス３１～３３に対して順次行うことによって、室内の暖房を継続しつつ、室外熱交換器１２３全体の除霜を行っている。しかも、この暖房デフロスト運転中にも過冷却パス３４に冷媒を通過させることができるため、熱交パス３１～３３の除霜によって溶けて室外熱交換器１２３の最下部まで流下したドレン水を加熱し、これにより、ドレンパンとして機能する底板５２の温度が低いことに起因してドレン水が再凍結することを防止している。 Then, after the defrosting of all the heat exchange paths 31 to 33 of the outdoor heat exchanger 123 is completed by the processing of steps S2 to S7, the heating operation is resumed (step S8).
As described above, the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 while defrosting any of the heat exchange paths 31 to 33 by the defrost flow path mechanism 126. Evaporative heating operation is performed. Then, the heating defrost operation is sequentially performed on the plurality of heat exchange paths 31 to 33, so that the entire outdoor heat exchanger 123 is defrosted while the indoor heating is continued. Moreover, since the refrigerant can be passed through the supercooling path 34 even during the heating defrosting operation, the drain water that has melted by the defrosting of the heat exchange paths 31 to 33 and has flowed to the bottom of the outdoor heat exchanger 123 is heated. Thus, the drain water is prevented from refreezing due to the low temperature of the bottom plate 52 functioning as a drain pan.
　（特徴）
　本実施形態の空気調和装置１０１では、第１実施形態の空気調和装置１と同様に、圧縮機２１において圧縮された冷媒の全流量を室内熱交換器４１に送って暖房に使用し（図２４及び図２５の点Ｂから点Ｃまでの行程を参照）、その後、室内熱交換器４１から室外熱交換器２３に送られる冷媒の熱によって除霜を行うことができる（図２４及び図２５の点Ｄから点Ｅまでの行程を参照）。このため、空気調和装置１０１の暖房デフロスト運転では、暖房能力をほとんど低下させることなく、室外熱交換器１２３の除霜を行うことができる。
　しかも、空気調和装置１０１では、暖房デフロスト運転中にも過冷却パス３４に冷媒を通過させることができるため、熱交パス３１～３３の除霜によって発生したドレン水の再凍結を防止して、室外熱交換器１２３の下部から速やかに排水することができる。 (Characteristic)
In the air conditioner 101 of the present embodiment, as in the air conditioner 1 of the first embodiment, the entire flow rate of the refrigerant compressed in the compressor 21 is sent to the indoor heat exchanger 41 and used for heating (FIG. 24). And the process from point B to point C in FIG. 25), and then defrosting can be performed by the heat of the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 23 (see FIGS. 24 and 25). (See the process from point D to point E). For this reason, in the heating defrost operation of the air conditioner 101, the outdoor heat exchanger 123 can be defrosted with almost no reduction in heating capacity.
Moreover, in the air conditioner 101, since the refrigerant can pass through the supercooling path 34 even during the heating defrost operation, the re-freezing of the drain water generated by the defrosting of the heat exchange paths 31 to 33 is prevented, Water can be quickly drained from the lower part of the outdoor heat exchanger 123.
　（変形例１）
　上記実施形態の暖房デフロスト運転においても、第１実施形態の変形例１（図１０を参照）と同様の暖房デフロスト運転を行うようにしてもよい。
　（変形例２）
　上記実施形態及び変形例１にかかる空気調和装置１０１では、デフロスト用流路機構１２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。
　例えば、図２６及び図２７に示すように、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、ヘッダー６６とを一体化した切換弁８２を使用するようにしてもよい。ここで、切換弁８２は、熱交パス供給管７１を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、熱交パス供給管７１を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するか、又は、いずれのヘッダー連絡管６５ａ～６５ｃにも冷媒を送らないことを選択する機能を有する切換弁である。ここでは、切換弁８２として、ロータリー式の切換弁が使用されている。この切換弁８２は、熱交パス供給管７１、ヘッダー連絡管６５ａ～６５ｃ及びガス冷媒管２８に接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ及びヘッダー側熱交パス選択弁７４ａ～７４ｃに代えて切換弁８２が制御部８に接続されている。尚、図２６は、本変形例にかかる空気調和装置１０１の概略構成図であり、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図２７は、本変形例の暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 1)
Also in the heating defrost operation of the above embodiment, the same heating defrost operation as that of the first modification of the first embodiment (see FIG. 10) may be performed.
(Modification 2)
In the air conditioner 101 according to the embodiment and the first modification, the defrosting flow path mechanism 126 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
For example, as shown in FIGS. 26 and 27, the heat exchange path branch pipes 72a to 72c, the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the header 66 Alternatively, a switching valve 82 that integrates the above may be used. Here, the switching valve 82 selects which of the header communication pipes 65a to 65c sends the refrigerant flowing through the heat exchange path supply pipe 71, and the header communication pipe through which the refrigerant flowing through the heat exchange path supply pipe 71 is sent. The other header communication pipes are switching valves having a function of connecting to the gas refrigerant pipe 28 or selecting not to send the refrigerant to any of the header communication pipes 65a to 65c. Here, a rotary switching valve is used as the switching valve 82. The switching valve 82 is connected to the heat exchange path supply pipe 71, the header communication pipes 65a to 65c, and the gas refrigerant pipe 28. In the configuration of this modified example, in the control block diagram of FIG. 2, the switching valve 82 is replaced with the control unit 8 in place of the branch pipe side heat exchange path selection valves 73a to 73c and the header side heat exchange path selection valves 74a to 74c. It is connected. FIG. 26 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 27 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
　このような構成であっても、図２６に示すように、いずれのヘッダー連絡管６５ａ～６５ｃにも冷媒を送らないように切換弁８２を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８２の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図２７に示すように、熱交パス供給管７１を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、熱交パス供給管７１を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁８２を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成に比べて、デフロスト用流路機構１２６を構成する部品点数を減らすことができる。 Even in such a configuration, as shown in FIG. 26, by operating the switching valve 82 so as not to send the refrigerant to any of the header communication pipes 65a to 65c, the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 82 as in the heating operation. Then, as shown in FIG. 27, it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the heat exchange path supply pipe 71 is sent to, and the header communication to which the refrigerant flowing through the heat exchange path supply pipe 71 is sent. By operating the switching valve 82 so that the header communication pipes other than the pipes are connected to the gas refrigerant pipe 28, the heating defrost operation similar to that in the above embodiment or the first modification can be performed.
And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, the number of parts which comprise the flow-path mechanism 126 for defrost can be reduced.
　（変形例３）
　上記実施形態及び変形例１にかかる空気調和装置１０１では、デフロスト用流路機構１２６が、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５とによって構成されているが、これに限定されるものではない。
　例えば、図２８及び図２９に示すように、熱交パス供給管７１と、熱交パス分岐管７２ａ～７２ｃと、分岐管側熱交パス選択弁７３ａ～７３ｃと、ヘッダー側熱交パス選択弁７４ａ～７４ｃと、分流管側選択弁７５と、ヘッダー６６とを一体化した切換弁８３を使用するようにしてもよい。ここで、切換弁８３は、過冷却パス－熱交パス連絡管３５を流れる冷媒を冷媒分流管６４に流すか又はヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、過冷却パス－熱交パス連絡管３５を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続する機能を有する切換弁である。ここでは、切換弁８３として、ロータリー式の切換弁が使用されている。この切換弁８３は、過冷却パス－熱交パス連絡管３５、冷媒分流管６４、ヘッダー連絡管６５ａ～６５ｃ及びガス冷媒管２８に接続されている。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ及び分流管側選択弁７５に代えて切換弁８３が制御部８に接続されている。尚、図２８は、本変形例にかかる空気調和装置１０１の概略構成図であり、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図２９は、本変形例の暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 3)
In the air conditioner 101 according to the embodiment and the first modification, the defrosting flow path mechanism 126 includes the heat exchange path supply pipe 71, the heat exchange path branch pipes 72a to 72c, and the branch pipe side heat exchange path selection valve 73a. To 73c, header side heat exchange path selection valves 74a to 74c, and branch pipe side selection valve 75, but is not limited thereto.
For example, as shown in FIGS. 28 and 29, a heat exchange path supply pipe 71, heat exchange path branch pipes 72a to 72c, branch pipe side heat exchange path selection valves 73a to 73c, and a header side heat exchange path selection valve. A switching valve 83 in which 74a to 74c, the branch pipe side selection valve 75, and the header 66 are integrated may be used. Here, the switching valve 83 selects whether the refrigerant flowing through the supercooling path-heat exchange path connecting pipe 35 flows to the refrigerant distribution pipe 64 or the header connecting pipes 65a to 65c, and the supercooling path A header connecting pipe other than the header connecting pipe to which the refrigerant flowing through the heat exchange path connecting pipe 35 is sent is a switching valve having a function of connecting to the gas refrigerant pipe 28. Here, a rotary type switching valve is used as the switching valve 83. The switching valve 83 is connected to the supercooling path-heat exchange path connecting pipe 35, the refrigerant branch pipe 64, the header connecting pipes 65 a to 65 c, and the gas refrigerant pipe 28. In the configuration of the present modification, switching is performed in place of the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the branch pipe side selection valve 75 in the control block diagram of FIG. A valve 83 is connected to the control unit 8. FIG. 28 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 29 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
　このような構成であっても、図２８に示すように、過冷却パス－熱交パス連絡管３５を流れる冷媒を冷媒分流管６４に流すように切換弁８３を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８３の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図２９に示すように、過冷却パス－熱交パス連絡管３５を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、液冷媒管２７を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁８３を動作させることによって、上記実施形態又は変形例１と同様の暖房デフロスト運転を行うことができる。
　そして、本変形例の構成では、上記実施形態及び変形例１の構成、さらには、変形例２の構成に比べて、デフロスト用流路機構１２６を構成する部品点数を減らすことができる。 Even in such a configuration, as shown in FIG. 28, by operating the switching valve 83 so that the refrigerant flowing in the supercooling path-heat exchange path connecting pipe 35 flows to the refrigerant distribution pipe 64, the above embodiment is implemented. The same heating operation can be performed. Further, the same cooling operation as that in the above embodiment can be performed in the operation state of the switching valve 83 similar to that in the heating operation. Then, as shown in FIG. 29, the refrigerant flowing through the supercooling path-heat exchange path connecting pipe 35 is selected to be sent to any of the header connecting pipes 65a to 65c, and the refrigerant flowing through the liquid refrigerant pipe 27 is sent. By operating the switching valve 83 so that the header communication pipes other than the header communication pipe are connected to the gas refrigerant pipe 28, the heating defrost operation similar to that in the above embodiment or the first modification can be performed.
And in the structure of this modification, compared with the structure of the said embodiment and the modification 1, and the structure of the modification 2, the number of parts which comprise the flow-path mechanism 126 for defrost can be reduced.
　（変形例４）
　上記実施形態及び変形例１にかかる空気調和装置１０１では、デフロスト用流路機構１２６が、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４を通過させた後に、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送ることができるように構成されている。しかし、暖房デフロスト運転において、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４に通過させる必要がない場合には、第１実施形態の暖房デフロスト運転と同様の冷媒の流れを得ることができるようにデフロスト用流路機構１２６を構成してもよい。
　例えば、図３０及び図３１に示すように、上記実施形態の空気調和装置１０１において、熱交パス供給管７１を液冷媒管２７の膨張弁２４と過冷却パス３４の液側端との間の位置から分岐させるようにして、熱交パス供給管７１に電磁弁７６を設けるようにしてもよい。そして、本変形例の構成では、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ及び分流管側選択弁７５とともに、電磁弁７６が制御部８に接続されている。尚、図３０は、本変形例にかかる空気調和装置１０１の概略構成図であり、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図３１は、本変形例の暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 4)
In the air conditioning apparatus 101 according to the embodiment and the first modification, after the defrosting flow path mechanism 126 passes the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 through the supercooling path 34, Without being introduced into the refrigerant flow divider 64, it is configured so that it can be sent to the gas side end of the heat exchange path arbitrarily selected from the plurality of heat exchange paths 31 to 33. However, in the heating defrost operation, when the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 does not need to pass through the supercooling path 34, the same refrigerant as in the heating defrost operation of the first embodiment. The defrost flow path mechanism 126 may be configured so as to obtain the above flow.
For example, as shown in FIGS. 30 and 31, in the air conditioner 101 of the above embodiment, the heat exchange path supply pipe 71 is connected between the expansion valve 24 of the liquid refrigerant pipe 27 and the liquid side end of the supercooling path 34. The electromagnetic valve 76 may be provided in the heat exchange path supply pipe 71 so as to be branched from the position. In the configuration of this modification, in the control block diagram of FIG. 2, the solenoid valve together with the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the branch pipe side selection valve 75 are provided. 76 is connected to the control unit 8. FIG. 30 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 31 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
　このような構成においては、図３０に示すように、分流管側選択弁７５を開け、かつ、電磁弁７６を閉止することによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の分流管側選択弁７５及び電磁弁７６の動作状態において、上記実施形態と同様の冷房運転を行うこともできる。そして、図３１に示すように、分流管側選択弁７５を閉止し、かつ、電磁弁７６を開けることによって、過冷却パス３４に冷媒を通過させることなく、第１実施形態と同様の暖房デフロスト運転を行うことができる。これにより、冷媒の熱を熱交パスの除霜だけに使用することができる。
　（変形例５）
　上記変形例２にかかる空気調和装置１０１では、デフロスト用流路機構１２６が、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４を通過させた後に、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送ることができるように構成されている。しかし、暖房デフロスト運転において、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４に通過させる必要がない場合には、第１実施形態の暖房デフロスト運転と同様の冷媒の流れを得ることができるようにデフロスト用流路機構１２６を構成してもよい。 In such a configuration, as shown in FIG. 30, the heating operation similar to that in the above embodiment can be performed by opening the branch pipe side selection valve 75 and closing the electromagnetic valve 76. Further, in the operation state of the branch pipe side selection valve 75 and the electromagnetic valve 76 similar to those in the heating operation, the same cooling operation as in the above embodiment can be performed. And as shown in FIG. 31, the heating defrost similar to 1st Embodiment is made without passing a refrigerant | coolant to the supercooling path | pass 34 by closing the shunt pipe side selection valve 75 and opening the electromagnetic valve 76. You can drive. Thereby, the heat of a refrigerant | coolant can be used only for defrosting of a heat exchange path.
(Modification 5)
In the air conditioner 101 according to the second modification, the defrosting channel mechanism 126 passes the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 through the supercooling path 34, and then the refrigerant distributor. The flow is configured to be sent to the gas side end of a heat exchange path arbitrarily selected from the plurality of heat exchange paths 31 to 33 without flowing into the heat exchange path. However, in the heating defrost operation, when the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 does not need to pass through the supercooling path 34, the same refrigerant as in the heating defrost operation of the first embodiment. The defrost flow path mechanism 126 may be configured so as to obtain the above flow.
　例えば、図３２及び図３３に示すように、上記変形例２の空気調和装置１０１において、熱交パス供給管７１を液冷媒管２７の膨張弁２４と過冷却パス３４の液側端との間の位置から分岐させるようにしてもよい。そして、本変形例の構成では、上記変形例２と同様に、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ及びヘッダー側熱交パス選択弁７４ａ～７４ｃに代えて切換弁８２が制御部８に接続されている。尚、図３２は、本変形例にかかる空気調和装置１０１の概略構成図であり、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図３３は、本変形例の暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。
　このような構成であっても、図３２に示すように、いずれのヘッダー連絡管６５ａ～６５ｃにも冷媒を送らないように切換弁８２を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８２の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図３３に示すように、分流管側選択弁７５を閉止し、かつ、熱交パス供給管７１を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、熱交パス供給管７１を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁８２を動作させることによって、過冷却パス３４に冷媒を通過させることなく、第１実施形態と同様の暖房デフロスト運転を行うことができる。 For example, as shown in FIGS. 32 and 33, in the air conditioner 101 of the second modification, the heat exchange path supply pipe 71 is connected between the expansion valve 24 of the liquid refrigerant pipe 27 and the liquid side end of the supercooling path 34. You may make it branch from the position of. In the configuration of the present modification, as in the second modification, in the control block diagram of FIG. 2, instead of the branch pipe side heat exchange path selection valves 73a to 73c and the header side heat exchange path selection valves 74a to 74c, A switching valve 82 is connected to the control unit 8. FIG. 32 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 33 is a diagram showing a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
Even in such a configuration, as shown in FIG. 32, by operating the switching valve 82 so that the refrigerant is not sent to any of the header communication pipes 65a to 65c, the heating operation similar to the above embodiment is performed. It can be carried out. Further, the same cooling operation as in the above embodiment can be performed in the operation state of the switching valve 82 as in the heating operation. Then, as shown in FIG. 33, the branch pipe side selection valve 75 is closed, the refrigerant flowing through the heat exchange path supply pipe 71 is selected to be sent to any one of the header communication pipes 65a to 65c, and the heat exchange is performed. By operating the switching valve 82 to connect the header communication pipe other than the header communication pipe through which the refrigerant flowing through the path supply pipe 71 is connected to the gas refrigerant pipe 28, the refrigerant does not pass through the supercooling path 34. A heating defrost operation similar to that of the first embodiment can be performed.
　（変形例６）
　上記変形例３にかかる空気調和装置１０１では、デフロスト用流路機構１２６が、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４を通過させた後に、冷媒分流器６４に流入させることなく、複数の熱交パス３１～３３のうち任意に選択された熱交パスのガス側端に送ることができるように構成されている。しかし、暖房デフロスト運転において、室内熱交換器４１から室外熱交換器１２３に送られる冷媒を、過冷却パス３４に通過させる必要がない場合には、第１実施形態の暖房デフロスト運転と同様の冷媒の流れを得ることができるようにデフロスト用流路機構１２６を構成してもよい。
　例えば、図３４及び図３５に示すように、上記変形例３の空気調和装置１０１において、過冷却パス－熱交パス連絡管３５に代えて液冷媒管２７を切換弁８３に接続するようにしてもよい。そして、本変形例の構成では、上記変形例３と同様に、図２の制御ブロック図において、分岐管側熱交パス選択弁７３ａ～７３ｃ、ヘッダー側熱交パス選択弁７４ａ～７４ｃ及び分流管側選択弁７５に代えて切換弁８３が制御部８に接続されている。尚、図３４は、本変形例にかかる空気調和装置１０１の概略構成図であり、暖房運転時における空気調和装置１０１内の冷媒の流れを示す図である。図３５は、本変形例の暖房デフロスト運転時における空気調和装置１０１内の冷媒の流れ（第１熱交パス３１の除霜を行う場合）を示す図である。 (Modification 6)
In the air conditioner 101 according to the third modification, the defrosting flow path mechanism 126 passes the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 through the supercooling path 34, and then the refrigerant distributor. The flow is configured to be sent to the gas side end of a heat exchange path arbitrarily selected from the plurality of heat exchange paths 31 to 33 without flowing into the heat exchange path. However, in the heating defrost operation, when the refrigerant sent from the indoor heat exchanger 41 to the outdoor heat exchanger 123 does not need to pass through the supercooling path 34, the same refrigerant as in the heating defrost operation of the first embodiment. The defrost flow path mechanism 126 may be configured so as to obtain the above flow.
For example, as shown in FIGS. 34 and 35, in the air conditioner 101 according to the third modification, the liquid refrigerant pipe 27 is connected to the switching valve 83 instead of the supercooling path-heat exchange path connecting pipe 35. Also good. In the configuration of this modification, as in the modification 3, the branch pipe side heat exchange path selection valves 73a to 73c, the header side heat exchange path selection valves 74a to 74c, and the shunt pipe in the control block diagram of FIG. Instead of the side selection valve 75, a switching valve 83 is connected to the control unit 8. FIG. 34 is a schematic configuration diagram of the air-conditioning apparatus 101 according to the present modification, and is a diagram illustrating the flow of refrigerant in the air-conditioning apparatus 101 during the heating operation. FIG. 35 is a diagram illustrating a refrigerant flow (when defrosting the first heat exchange path 31) in the air-conditioning apparatus 101 during the heating defrost operation of the present modification.
　このような構成であっても、図３４に示すように、液冷媒管２７を流れる冷媒が過冷却パス－熱交パス連絡管３５に流すように切換弁８３を動作させることによって、上記実施形態と同様の暖房運転を行うことができる。また、暖房運転時と同様の切換弁８３の動作状態において上記実施形態と同様の冷房運転を行うこともできる。そして、図３５に示すように、液冷媒管２７を流れる冷媒をヘッダー連絡管６５ａ～６５ｃのいずれに送るかを選択し、かつ、液冷媒管２７を流れる冷媒が送られるヘッダー連絡管以外のヘッダー連絡管についてはガス冷媒管２８に接続するように切換弁８３を動作させることによって、過冷却パス３４に冷媒を通過させることなく、第１実施形態と同様の暖房デフロスト運転を行うことができる。
　＜他の実施形態＞
　以上、本発明の実施形態及びその変形例について図面に基づいて説明したが、具体的な構成は、これらの実施形態及びその変形例に限られるものではなく、発明の要旨を逸脱しない範囲で変更可能である。 Even in such a configuration, as shown in FIG. 34, by operating the switching valve 83 so that the refrigerant flowing through the liquid refrigerant pipe 27 flows into the supercooling path-heat exchange path connecting pipe 35, the above embodiment is implemented. The same heating operation can be performed. Further, the same cooling operation as that in the above embodiment can be performed in the operation state of the switching valve 83 similar to that in the heating operation. Then, as shown in FIG. 35, it is selected which of the header communication pipes 65a to 65c the refrigerant flowing through the liquid refrigerant pipe 27 is sent to, and a header other than the header communication pipe to which the refrigerant flowing through the liquid refrigerant pipe 27 is sent. By operating the switching valve 83 so as to connect the communication pipe to the gas refrigerant pipe 28, the heating defrost operation similar to that of the first embodiment can be performed without allowing the refrigerant to pass through the supercooling path 34.
<Other embodiments>
As mentioned above, although embodiment of this invention and its modification were demonstrated based on drawing, specific structure is not restricted to these embodiment and its modification, It changes in the range which does not deviate from the summary of invention. Is possible.
　（Ａ）
　上記実施形態及びその変形例のうち、分岐管側熱交パス選択弁７３ａ～７３ｃを有する第１実施形態（図１等を参照）や第２実施形態（図２１等を参照）の構成では、デフロスト用流路機構２６、１２６が、熱交パス供給管７１及び熱交パス分岐管７２ａ～７２ｃを有する構成になっている。
　しかし、図３６に示すように、熱交パス供給管７１及び熱交パス分岐管７２ａ～７２ｃに代えて、ヘッダー６８を有する構成を採用してもよい。この構成では、液冷媒管２７をヘッダー６８に直接接続し、ヘッダー６８に分岐管側熱交パス選択弁７３ａ～７３ｃの一端を直接接続し、ヘッダー連絡管６５ａ～６５ｃに分岐管側熱交パス選択弁７３ａ～７３ｃの他端を直接接続するようにしている。尚、図３６では、第１実施形態の構成において、ヘッダー６８を有するデフロスト用流路機構２６を採用した例を図示しているが、第２実施形態の構成においては、図３７に示すように、過冷却パス－熱交パス連絡管３５にヘッダー６８を直接接続したデフロスト用流路機構１２６を採用すればよい。 (A)
Among the above-described embodiments and modifications thereof, in the configuration of the first embodiment (see FIG. 1 and the like) and the second embodiment (see FIG. 21 and the like) having the branch pipe side heat exchange path selection valves 73a to 73c, The defrost flow path mechanisms 26, 126 are configured to include a heat exchange path supply pipe 71 and heat exchange path branch pipes 72a to 72c.
However, as shown in FIG. 36, a configuration having a header 68 may be employed in place of the heat exchange path supply pipe 71 and the heat exchange path branch pipes 72a to 72c. In this configuration, the liquid refrigerant pipe 27 is directly connected to the header 68, one end of the branch pipe side heat exchange path selection valves 73a to 73c is directly connected to the header 68, and the branch pipe side heat exchange path is connected to the header communication pipes 65a to 65c. The other ends of the selection valves 73a to 73c are directly connected. FIG. 36 shows an example in which the defrost flow path mechanism 26 having the header 68 is adopted in the configuration of the first embodiment. However, in the configuration of the second embodiment, as shown in FIG. The defrosting flow path mechanism 126 in which the header 68 is directly connected to the supercooling path-heat exchange path connecting pipe 35 may be employed.
　このような構成であっても、上記実施形態及びその変形例と同様の暖房デフロスト運転を行うことができる。そして、これらの構成では、分岐管側熱交パス選択弁７３ａ～７３ｃを有するデフロスト用流路機構２６、１２６の構成でありながら、熱交パス供給管７１及び熱交パス分岐管７２ａ～７２ｃを省略することができ、デフロスト用流路機構２６、１２６の構成を簡素化することができる。
　（Ｂ）
　上記実施形態及びその変形例では、１つの室外ユニットに１つの室内ユニットが接続された構成であったが、これに限定されるものではない。例えば、室外ユニットに複数の室内ユニットが接続された構成や、複数の室外ユニットに１つの室内ユニットが接続された構成、複数の室外ユニットに複数の室内ユニットが接続された構成であってもよい。 Even with such a configuration, the same heating defrost operation as that of the above-described embodiment and the modification thereof can be performed. In these structures, the defrost flow path mechanisms 26 and 126 having the branch pipe side heat exchange path selection valves 73a to 73c are used, but the heat exchange path supply pipe 71 and the heat exchange path branch pipes 72a to 72c are provided. This can be omitted, and the configuration of the defrosting channel mechanisms 26 and 126 can be simplified.
(B)
In the said embodiment and its modification, although it was the structure by which one indoor unit was connected to one outdoor unit, it is not limited to this. For example, a configuration in which a plurality of indoor units are connected to the outdoor unit, a configuration in which one indoor unit is connected to the plurality of outdoor units, or a configuration in which a plurality of indoor units are connected to the plurality of outdoor units may be employed. .
　また、上記実施形態及びその変形例では、四路切換弁によって冷房と暖房とを切り換え可能な空気調和装置であったが、これに限定されるものではない。例えば、暖房専用の構成（すなわち、四路切換弁なしで室内熱交換器を常時放熱器として使用する構成）であってもよい。
　（Ｃ）
　上記実施形態及びその変形例では、横方向に室外空気を吹き出すタイプの室外ユニットを採用しているが、これに限定されるものではない。例えば、室外熱交換器の上方に室外ファンを設置することで上方向に室外空気を吹き出すタイプの室外ユニット等のように、他のタイプの室外ユニットであってもよい。
　（Ｄ）
　上記実施形態及びその変形例では、室外熱交換器として、クロスフィン式のフィン・アンド・チューブ型熱交換器を採用しているが、これに限定されるものではない。例えば、コルゲートフィンを使用した積層型熱交換器等のように、他の型式の熱交換器であってもよい。また、室外熱交換器を構成する熱交パスの数は、３つに限定されるものではなく、４つ以上であってもよい。 Moreover, in the said embodiment and its modification, although it was an air conditioning apparatus which can switch between cooling and heating with a four-way switching valve, it is not limited to this. For example, a configuration dedicated to heating (that is, a configuration in which an indoor heat exchanger is always used as a radiator without a four-way switching valve) may be used.
(C)
In the said embodiment and its modification, although the outdoor unit of the type which blows off outdoor air to a horizontal direction is employ | adopted, it is not limited to this. For example, other types of outdoor units such as an outdoor unit that blows outdoor air upward by installing an outdoor fan above the outdoor heat exchanger may be used.
(D)
In the said embodiment and its modification, although the cross fin type fin and tube type heat exchanger is employ | adopted as an outdoor heat exchanger, it is not limited to this. For example, another type of heat exchanger may be used such as a laminated heat exchanger using corrugated fins. Further, the number of heat exchange paths constituting the outdoor heat exchanger is not limited to three, and may be four or more.
　本発明は、暖房運転を行うことが可能な空気調和装置に対して広く適用可能である。 The present invention is widely applicable to an air conditioner capable of performing a heating operation.
　１、１０１　　空気調和装置
　２１　　　　　圧縮機
　２３、１２３　室外熱交換器
　２６、１２６　デフロスト用流路機構
　３１～３３　　熱交パス
　３４　　　　　過冷却パス
　４１　　　　　室内熱交換器
　６４　　　　　冷媒分流器 DESCRIPTION OF SYMBOLS 1,101 Air conditioning apparatus 21 Compressor 23, 123 Outdoor heat exchanger 26, 126 Flow path mechanism for defrost 31-33 Heat exchange path 34 Subcooling path 41 Indoor heat exchanger 64 Refrigerant flow divider
特開２０００－２７４７８０号公報JP 2000-274780 A 特開２００１－０５９９９４号公報JP 2001-059994 A

Claims (3)

  1. 　冷媒を圧縮する圧縮機（２１）と、前記圧縮機において圧縮された冷媒の放熱を行う室内熱交換器（４１）と、前記室内熱交換器において放熱した冷媒を室外空気との熱交換によって蒸発させる室外熱交換器（２３、１２３）と、が順次接続されることによって構成されており、前記圧縮機、前記室内熱交換器、前記室外熱交換器、前記圧縮機の順に冷媒を循環させる暖房運転を行うことが可能な空気調和装置において、
    　前記室外熱交換器は、互いが並列に接続された複数の熱交パス（３１～３３）を有しており、
    　前記複数の熱交パスの液側端は、前記室内熱交換器から前記室外熱交換器に送られる冷媒を前記複数の熱交パスの液側端に分岐するための冷媒分流器（６４）によって並列に接続されており、
    　前記室内熱交換器から前記室外熱交換器に送られる冷媒を、前記冷媒分流器に流入させることなく、前記複数の熱交パスのうち任意に選択された熱交パスのガス側端に送るためのデフロスト用流路機構（２６、１２６）が設けられており、
    　前記室内熱交換器から前記室外熱交換器に送られる冷媒を、前記デフロスト用流路機構によって、前記冷媒分流器に流入させることなく、前記任意の熱交パスのガス側端から液側端に向かって前記任意の熱交パス内を通過させ、前記任意の熱交パスを通過した冷媒を、前記冷媒分流器を通じて、前記任意の熱交パス以外の他の熱交パスの液側端からガス側端に向かって前記他の熱交パス内を通過させることで、前記任意の熱交パスの除霜を行いつつ、前記室内熱交換器から前記室外熱交換器に送られる冷媒を蒸発させる暖房デフロスト運転を行う、
    空気調和装置（１、１０１）。     A compressor (21) that compresses the refrigerant, an indoor heat exchanger (41) that radiates heat of the refrigerant compressed in the compressor, and the refrigerant that has radiated heat in the indoor heat exchanger is evaporated by heat exchange with outdoor air. And the outdoor heat exchanger (23, 123) to be connected are sequentially connected, and the refrigerant is circulated in the order of the compressor, the indoor heat exchanger, the outdoor heat exchanger, and the compressor. In an air conditioner that can be operated,
    The outdoor heat exchanger has a plurality of heat exchange paths (31 to 33) connected in parallel to each other,
    The liquid side ends of the plurality of heat exchange paths are separated by a refrigerant shunt (64) for branching the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to the liquid side ends of the plurality of heat exchange paths. Connected in parallel,
    In order to send the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to the gas side end of the heat exchange path arbitrarily selected from the plurality of heat exchange paths without flowing into the refrigerant distributor. The defrost flow path mechanism (26, 126) is provided,
    The refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger is caused to flow from the gas side end to the liquid side end of the arbitrary heat exchange path without flowing into the refrigerant diverter by the defrost flow path mechanism. The refrigerant passing through the arbitrary heat exchange path toward the gas and passing through the arbitrary heat exchange path passes through the refrigerant diverter from the liquid side end of the other heat exchange path other than the arbitrary heat exchange path. Heating that evaporates the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger while defrosting the arbitrary heat exchange path by passing through the other heat exchange path toward the side end Perform defrost operation,
    Air conditioner (1, 101).
  2. 　前記室外熱交換器（１２３）は、前記室内熱交換器（４１）から前記室外熱交換器に送られる冷媒が前記冷媒分流器（６４）に流入する前に通過する過冷却パス（３４）をさらに有しており、
    　前記デフロスト用流路機構（１２６）は、前記室内熱交換器から前記室外熱交換器に送られる冷媒を、前記過冷却パスを通過させた後に、前記複数の熱交パス（３１～３３）のうち任意に選択された熱交パスのガス側端に送ることができるように設けられている、
    請求項１に記載の空気調和装置（１０１）。     The outdoor heat exchanger (123) passes through a supercooling path (34) through which the refrigerant sent from the indoor heat exchanger (41) to the outdoor heat exchanger passes before flowing into the refrigerant distributor (64). In addition,
    The defrost flow path mechanism (126) passes the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger through the supercooling path, and then passes through the plurality of heat exchange paths (31 to 33). It is provided so that it can be sent to the gas side end of the heat exchange path selected arbitrarily,
    The air conditioner (101) according to claim 1.
  3. 　前記室外熱交換器（１２３）は、前記室内熱交換器（４１）から前記室外熱交換器に送られる冷媒が前記冷媒分流器（６４）に流入する前に通過する過冷却パス（３４）をさらに有しており、
    　前記デフロスト用流路機構（１２６）は、前記室内熱交換器から前記室外熱交換器に送られる冷媒を、前記過冷却パスを通過させることなく、前記複数の熱交パス（３１～３３）のうち任意に選択された熱交パスのガス側端に送ることができるように設けられている、
    請求項１に記載の空気調和装置（１０１）。     The outdoor heat exchanger (123) passes through a supercooling path (34) through which the refrigerant sent from the indoor heat exchanger (41) to the outdoor heat exchanger passes before flowing into the refrigerant distributor (64). In addition,
    The defrost flow path mechanism (126) is configured to allow the refrigerant sent from the indoor heat exchanger to the outdoor heat exchanger to pass through the plurality of heat exchange paths (31 to 33) without passing through the supercooling path. It is provided so that it can be sent to the gas side end of the heat exchange path selected arbitrarily,
    The air conditioner (101) according to claim 1.
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EP2741021A4 (en) 2014-07-09
KR20140026630A (en) 2014-03-05
US20140116078A1 (en) 2014-05-01
CN103635754A (en) 2014-03-12
EP2741021A1 (en) 2014-06-11

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