EP4321820A1 - Air conditioner - Google Patents
Air conditioner Download PDFInfo
- Publication number
- EP4321820A1 EP4321820A1 EP21936008.8A EP21936008A EP4321820A1 EP 4321820 A1 EP4321820 A1 EP 4321820A1 EP 21936008 A EP21936008 A EP 21936008A EP 4321820 A1 EP4321820 A1 EP 4321820A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- way valve
- refrigerant
- heat exchange
- exchange portion
- air
- Prior art date
- Legal status (The legal status 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 status listed.)
- Pending
Links
- 239000003507 refrigerant Substances 0.000 claims abstract description 189
- 238000007791 dehumidification Methods 0.000 claims abstract description 51
- 238000003303 reheating Methods 0.000 claims abstract description 47
- 238000001816 cooling Methods 0.000 claims abstract description 38
- 238000010438 heat treatment Methods 0.000 description 22
- 239000007788 liquid Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 8
- 239000012071 phase Substances 0.000 description 8
- 238000010276 construction Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 2
- 238000007664 blowing Methods 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/0007—Indoor units, e.g. fan coil units
- F24F1/0068—Indoor units, e.g. fan coil units characterised by the arrangement of refrigerant piping outside the heat exchanger within the unit casing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0234—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements
- F25B2313/02341—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements during cooling
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0234—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements
- F25B2313/02343—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements during dehumidification
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0234—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements
- F25B2313/02344—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in series arrangements during heating
-
- 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
- F25B2313/02743—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using three four-way valves
Definitions
- the present disclosure relates to an air-conditioner.
- An air-conditioner capable of performing both of a cooling operation and a reheating dehumidification operation has conventionally been proposed.
- Such an air-conditioner is described, for example, in Japanese Patent Laying-Open No. 2020-125855 (PTL 1).
- PTL 1 Japanese Patent Laying-Open No. 2020-125855
- a four-way valve provided in a refrigerant circuit switches a flow path of refrigerant so that an orientation of refrigerant that flows in an indoor heat exchanger is different between the cooling operation and the reheating dehumidification operation.
- the indoor heat exchanger is divided into a plurality of heat exchange portions and an expansion valve is provided between the plurality of divided heat exchange portions.
- a heat exchanger is normally designed such that, when the heat exchanger is used as an evaporator, air that flows on the outside of the heat exchanger and refrigerant that flows in the inside of the heat exchanger are parallel flows with orientations thereof being the same, for the following reason.
- a density of refrigerant is low and a flow velocity of refrigerant is high. Therefore, pressure loss in the evaporator is greater than pressure loss in a condenser. Accordingly, a saturation temperature at an outlet of the evaporator is lower than a saturation temperature at an inlet of the evaporator.
- a temperature of refrigerant becomes lower with cooling of air, and hence the temperature at the outlet is lower than in an example where air and refrigerant flow as counterflows. Air can thus efficiently be cooled.
- the present disclosure was made in view of the problems above, and an object thereof is to provide an air-conditioner capable of sufficient dehumidification in a reheating dehumidification operation.
- An air-conditioner in the present disclosure is provided with a refrigerant circuit and an indoor fan.
- the refrigerant circuit has a compressor, a first four-way valve, an outdoor heat exchanger, a first expansion valve, a second four-way valve, a third four-way valve, an indoor heat exchanger, and a second expansion valve, and is configured to circulate refrigerant.
- the indoor fan is configured to send air to the indoor heat exchanger.
- the indoor heat exchanger has a first heat exchange portion and a second heat exchange portion.
- the first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second expansion valve, the second heat exchange portion, the second four-way valve, and the first four-way valve during a cooling operation.
- the first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the second heat exchange portion, the second expansion valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second four-way valve, and the first four-way valve during a reheating dehumidification operation.
- a flow of refrigerant with respect to a flow of air sent by the indoor fan is a parallel flow.
- the flow of refrigerant with respect to the flow of air is a parallel flow
- the flow of refrigerant with respect to the flow of air is a counterflow
- the flow of refrigerant with respect to the flow of air is the parallel flow. Therefore, sufficient dehumidification can be achieved in the reheating dehumidification operation.
- FIG. 1 A construction of an air-conditioner 100 according to a first embodiment will be described with reference to Fig. 1 .
- air-conditioner 100 is provided with a refrigerant circuit RC, an outdoor fan 9, an indoor fan 10, and a control device 11.
- Refrigerant circuit RC has a compressor 1, a first four-way valve 2, an outdoor heat exchanger 3, a first expansion valve 4, a second four-way valve 5, a third four-way valve 6, an indoor heat exchanger 7, a second expansion valve 8, and a pipe P.
- Indoor heat exchanger 7 has a first heat exchange portion 7a and a second heat exchange portion 7b.
- Pipe P includes a first extension pipe P1 and a second extension pipe P2.
- Refrigerant circuit RC is constructed by connection of compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, third four-way valve 6, indoor heat exchanger 7, and second expansion valve 8 through pipe P.
- Refrigerant circuit RC is constructed to circulate refrigerant.
- Air-conditioner 100 includes an outdoor unit 101 and an indoor unit 102. Outdoor unit 101 and indoor unit 102 are connected to each other through first extension pipe P1 and second extension pipe P2. Compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, outdoor fan 9, and control device 11 are accommodated in outdoor unit 101. Third four-way valve 6, indoor heat exchanger 7, second expansion valve 8, and indoor fan 10 are accommodated in indoor unit 102.
- Compressor 1 is constructed to compress refrigerant.
- Compressor 1 is constructed to compress and discharge suctioned refrigerant.
- Compressor 1 is, for example, of a variable displacement type.
- Compressor 1 is constructed as being variable in capacity, for example, by adjustment of the number of rotations of compressor 1 based on an instruction from control device 11.
- First four-way valve 2 is connected to an inlet and an outlet of compressor 1, outdoor heat exchanger 3, and second four-way valve 5.
- First four-way valve 2 is constructed to switch a flow of refrigerant such that refrigerant compressed by compressor 1 flows to outdoor heat exchanger 3 or indoor heat exchanger 7.
- first four-way valve 2 switches the flow of refrigerant such that refrigerant compressed by compressor 1 flows to indoor heat exchanger 7, refrigerant flows from first four-way valve 2 through second four-way valve 5 to indoor heat exchanger 7.
- First four-way valve 2 is constructed to allow refrigerant discharged from compressor 1 to flow to outdoor heat exchanger 3 during a cooling operation and a reheating dehumidification operation.
- First four-way valve 2 is constructed to allow refrigerant discharged from compressor 1 to flow to indoor heat exchanger 7 during a heating operation.
- Outdoor heat exchanger 3 is constructed to exchange heat between refrigerant that flows in the inside of outdoor heat exchanger 3 and air that flows on the outside of outdoor heat exchanger 3. Outdoor heat exchanger 3 is constructed to function as a condenser that condenses refrigerant during the cooling operation and the reheating dehumidification operation. Outdoor heat exchanger 3 is constructed to function as an evaporator that evaporates refrigerant during the heating operation. Outdoor heat exchanger 3 is, for example, a finned tube heat exchanger having a plurality of fins and a heat transfer tube that passes through the plurality of fins.
- First expansion valve 4 is constructed to decompress by expanding, refrigerant condensed by the condenser.
- First expansion valve 4 is constructed to decompress refrigerant condensed by outdoor heat exchanger 3 during the cooling operation and the reheating dehumidification operation.
- First expansion valve 4 is constructed to decompress refrigerant condensed by indoor heat exchanger 7 during the heating operation.
- a solenoid expansion valve is employed as the first expansion valve.
- Second four-way valve 5 is connected to first four-way valve 2, first expansion valve 4, third four-way valve 6, and second heat exchange portion 7b of indoor heat exchanger 7.
- Second four-way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that flows out of first expansion valve 4 flows through third four-way valve 6 to first heat exchange portion 7a of indoor heat exchanger 7 and refrigerant that flows out of second heat exchange portion 7b of indoor heat exchanger 7 flows to first four-way valve 2 during the cooling operation.
- Second four-way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that flows out of first expansion valve 4 flows to second heat exchange portion 7b of indoor heat exchanger 7 and refrigerant that flows out of first heat exchange portion 7a of indoor heat exchanger 7 and passes through third four-way valve 6 flows to first four-way valve 2 during the reheating dehumidification operation.
- Second four-way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that is discharged from compressor 1 and passes through first four-way valve 2 flows to second heat exchange portion 7b of indoor heat exchanger 7 and refrigerant that flows out of first heat exchange portion 7a of indoor heat exchanger 7 and passes through third four-way valve 6 flows to first expansion valve 4 during the heating operation.
- Third four-way valve 6 is connected to second four-way valve 5, an inlet and an outlet of first heat exchange portion 7a of indoor heat exchanger 7, and second expansion valve 8.
- Third four-way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out of second four-way valve 5 flows to a heat transfer tube on a windward side of first heat exchange portion 7a and refrigerant that flows out of a heat transfer tube on a leeward side of first heat exchange portion 7a flows through second expansion valve 8 to a heat transfer tube on the windward side of second heat exchange portion 7b of indoor heat exchanger 7 during the cooling operation.
- Third four-way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out of second expansion valve 8 flows to the heat transfer tube on the windward side of first heat exchange portion 7a and refrigerant that flows out of the heat transfer tube on the leeward side of first heat exchange portion 7a flows to second four-way valve 5 during the reheating dehumidification operation.
- Third four-way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out of second expansion valve 8 flows to the heat transfer tube on the leeward side of first heat exchange portion 7a and refrigerant that flows out of the heat transfer tube on the windward side of first heat exchange portion 7a flows to second four-way valve 5 during the heating operation.
- Indoor heat exchanger 7 is constructed to exchange heat between refrigerant that flows in the inside of indoor heat exchanger 7 and air that flows on the outside of indoor heat exchanger 7.
- Indoor heat exchanger 7 is constructed to function as the evaporator that evaporates refrigerant during the cooling operation.
- Both of first heat exchange portion 7a and second heat exchange portion 7b are constructed to function as the evaporator that evaporates refrigerant during the cooling operation.
- Indoor heat exchanger 7 is constructed to function as the evaporator that evaporates refrigerant and the condenser that condenses refrigerant during the reheating dehumidification operation.
- First heat exchange portion 7a is constructed to function as the evaporator that evaporates refrigerant during the reheating dehumidification operation.
- Second heat exchange portion 7b is constructed to function as the condenser that condenses refrigerant during the reheating dehumidification operation.
- Indoor heat exchanger 7 is constructed to function as the condenser that condenses refrigerant during the heating operation. Both of first heat exchange portion 7a and second heat exchange portion 7b are constructed to function as the condenser that condenses refrigerant during the heating operation.
- Indoor heat exchanger 7 is, for example, a finned tube heat exchanger having a plurality of fins and a heat transfer tube that passes through the plurality of fins.
- First heat exchange portion 7a and second heat exchange portion 7b are arranged as being aligned in a direction of flow of air sent by indoor fan 10.
- First heat exchange portion 7a is arranged on the windward side relative to second heat exchange portion 7b in the flow of air sent by indoor fan 10.
- Second heat exchange portion 7b is arranged on the leeward side relative to first heat exchange portion 7a in the flow of air sent by indoor fan 10.
- First heat exchange portion 7a has the heat transfer tube on the windward side and the heat transfer tube on the leeward side.
- the heat transfer tube on the windward side is connected to the heat transfer tube of the leeward side.
- First heat exchange portion 7a is constructed such that refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side during the cooling operation and the reheating dehumidification operation.
- refrigerant and air that flow in first heat exchange portion 7a flow as parallel flows.
- First heat exchange portion 7a is constructed such that refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side during the heating operation.
- refrigerant and air that flow in first heat exchange portion 7a flow as counterflows.
- Second heat exchange portion 7b has the heat transfer tube on the windward side and a heat transfer tube on the leeward side.
- the heat transfer tube on the windward side is connected to the heat transfer tube on the leeward side.
- Second heat exchange portion 7b is constructed such that refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side during the cooling operation.
- refrigerant and air that flow in second heat exchange portion 7b flow as parallel flows.
- Second heat exchange portion 7b is constructed such that refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side during the reheating dehumidification operation and the heating operation.
- refrigerant and air that flow in second heat exchange portion 7b flow as counterflows.
- Second expansion valve 8 is constructed to decompress refrigerant condensed in second heat exchange portion 7b of indoor heat exchanger 7 during the reheating dehumidification operation. Second expansion valve 8 is constructed to suppress decompression of refrigerant by increasing an opening of the valve during the cooling operation and the heating operation. For example, a solenoid expansion valve is employed as second expansion valve 8.
- First four-way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, third four-way valve 6, first heat exchange portion 7a, third four-way valve 6, second expansion valve 8, second heat exchange portion 7b, second four-way valve 5, and first four-way valve 2 during the cooling operation.
- First four-way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, second heat exchange portion 7b, second expansion valve 8, third four-way valve 6, first heat exchange portion 7a, third four-way valve 6, second four-way valve 5, and first four-way valve 2 during the reheating dehumidification operation.
- First four-way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, second four-way valve 5, second heat exchange portion 7b, second expansion valve 8, third four-way valve 6, first heat exchange portion 7a, third four-way valve 6, second four-way valve 5, first expansion valve 4, outdoor heat exchanger 3, and first four-way valve 2 during the heating operation.
- Outdoor fan 9 is constructed to send air to outdoor heat exchanger 3. In other words, outdoor fan 9 is constructed to supply outdoor air to outdoor heat exchanger 3.
- Indoor fan 10 is constructed to send air to indoor heat exchanger 7.
- indoor fan 10 is constructed to supply indoor air to indoor heat exchanger 7.
- first heat exchange portion 7a and second heat exchange portion 7b the flow of refrigerant with respect to the flow of air sent by indoor fan 10 is the parallel flow.
- first heat exchange portion 7a the flow of refrigerant with respect to the flow of air sent by indoor fan 10 is the parallel flow
- second heat exchange portion 7b the flow of refrigerant with respect to the flow of air is the counterflow.
- the flow of refrigerant with respect to the flow of air sent by indoor fan 10 is the counterflow.
- Control device 11 is configured to control each device in air-conditioner 100 by performing computation and giving an instruction.
- Control device 11 is electrically connected to compressor 1, first four-way valve 2, first expansion valve 4, second four-way valve 5, third four-way valve 6, second expansion valve 8, outdoor fan 9, indoor fan 10, and the like and configured to control operations thereof.
- Air-conditioner 100 can selectively perform the cooling operation, the reheating dehumidification operation, and the heating operation.
- refrigerant circulates through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, third four-way valve 6, first heat exchange portion 7a of indoor heat exchanger 7, third four-way valve 6, second expansion valve 8, second heat exchange portion 7b of indoor heat exchanger 7, second four-way valve 5, and first four-way valve 2.
- High-pressure gas refrigerant discharged from compressor 1 flows into outdoor heat exchanger 3 through first four-way valve 2.
- outdoor heat exchanger 3 heat is exchanged between high-pressure gas refrigerant and air sent by outdoor fan 9, so that refrigerant radiates heat and changes to liquid refrigerant.
- Liquid refrigerant flows from outdoor heat exchanger 3 into first expansion valve 4.
- first expansion valve 4 liquid refrigerant is decompressed and becomes gas-liquid two-phase refrigerant.
- Gas-liquid two-phase refrigerant flows into second four-way valve 5 from first expansion valve 4.
- a flow path in second four-way valve 5 is switched to connect first expansion valve 4 and first extension pipe P1 to each other.
- Gas-liquid two-phase refrigerant passes through first extension pipe P1 from second four-way valve 5 and flows into third four-way valve 6.
- third four-way valve 6 the flow path is switched to connect first extension pipe P1 and the heat transfer tube on the windward side of first heat exchange portion 7a of indoor heat exchanger 7 to each other.
- Refrigerant flows again into third four-way valve 6 from first heat exchange portion 7a and thereafter flows into second expansion valve 8.
- the opening of second expansion valve 8 is set to increase. Therefore, since the pressure loss of refrigerant is less likely in second expansion valve 8, refrigerant flows as it is into the heat transfer tube on the windward side of second heat exchange portion 7b of indoor heat exchanger 7 from second expansion valve 8.
- Air cooled in first heat exchange portion 7a is sent to second heat exchange portion 7b.
- air that flows on the outside of second heat exchange portion 7b and refrigerant that flows in the inside of second heat exchange portion 7b are in the same orientation.
- the flow of refrigerant with respect to the flow of air is the parallel flow.
- Gas refrigerant that has evaporated in second heat exchange portion 7b flows from second heat exchange portion 7b through second extension pipe P2 into second four-way valve 5.
- second four-way valve 5 the flow path is switched to connect second extension pipe P2 and first four-way valve 2 to each other.
- Gas refrigerant flows from second four-way valve 5 through first four-way valve 2 into the inlet of compressor 1.
- refrigerant circulates through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, outdoor heat exchanger 3, first expansion valve 4, second four-way valve 5, second heat exchange portion 7b of indoor heat exchanger 7, second expansion valve 8, third four-way valve 6, first heat exchange portion 7a of indoor heat exchanger 7, third four-way valve 6, second four-way valve 5, and first four-way valve 2.
- second four-way valve 5 and third four-way valve 6 are switched from a state thereof in the cooling operation shown in Fig. 1 .
- Liquid refrigerant that has exchanged heat with air sent by outdoor fan 9 in outdoor heat exchanger 3 flows into first expansion valve 4.
- the temperature of refrigerant at an outlet of first expansion valve 4 can be higher than the temperature of indoor air.
- Refrigerant flows from first expansion valve 4 into second four-way valve 5.
- the flow path in second four-way valve 5 is switched to connect first expansion valve 4 and second extension pipe P2 to each other.
- Refrigerant passes through second extension pipe P2 from second four-way valve 5 and flows into second heat exchange portion 7b of indoor heat exchanger 7.
- Refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side in second heat exchange portion 7b of indoor heat exchanger 7.
- second heat exchange portion 7b refrigerant heats air cooled in first heat exchange portion 7a.
- air that flows on the outside of second heat exchange portion 7b and refrigerant that flows in the inside of second heat exchange portion 7b are in orientations reverse to each other. In other words, in second heat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the counterflow.
- Refrigerant flows into second expansion valve 8 from second heat exchange portion 7b. Refrigerant is decompressed in second expansion valve 8 and thereafter flows into third four-way valve 6. Refrigerant flows from third four-way valve 6 into the heat transfer tube on the windward side of first heat exchange portion 7a. Refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side in first heat exchange portion 7a. Refrigerant cools air in first heat exchange portion 7a. At this time, air that flows on the outside of first heat exchange portion 7a and refrigerant that flows in the inside of first heat exchange portion 7a are in the same orientation. In other words, in first heat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the parallel flow.
- Refrigerant that has cooled indoor air flows again into third four-way valve 6 from first heat exchange portion 7a and then passes through first extension pipe P1 and flows into second four-way valve 5.
- second four-way valve 5 the flow path is switched to connect first extension pipe P1 and first four-way valve 2 to each other.
- Refrigerant flows from second four-way valve 5 through first four-way valve 2 into the inlet of compressor 1.
- refrigerant circulates through refrigerant circuit RC in the order of compressor 1, first four-way valve 2, second four-way valve 5, second heat exchange portion 7b of indoor heat exchanger 7, second expansion valve 8, third four-way valve 6, first heat exchange portion 7a of indoor heat exchanger 7, third four-way valve 6, second four-way valve 5, first expansion valve 4, outdoor heat exchanger 3, and first four-way valve 2.
- first four-way valve 2 is switched from the state thereof in the cooling operation shown in Fig. 1 .
- High-pressure gas refrigerant discharged from compressor 1 flows through first four-way valve 2 and second four-way valve 5 into second heat exchange portion 7b of indoor heat exchanger 7.
- Refrigerant is condensed in second heat exchange portion 7b. Air that flows on the outside of second heat exchange portion 7b and refrigerant that flows in the inside of second heat exchange portion 7b are in orientations reverse to each other. In other words, in second heat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the counterflow.
- the opening of second expansion valve 8 is set to increase.
- Refrigerant is condensed in first heat exchange portion 7a. Air that flows on the outside of first heat exchange portion 7a and refrigerant that flows in the inside of first heat exchange portion 7a are in orientations reverse to each other. In other words, in first heat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the counterflow.
- Refrigerant flows from first heat exchange portion 7a through third four-way valve 6 and second four-way valve 5 into first expansion valve 4. Refrigerant is decompressed in first expansion valve 4. Refrigerant flows into outdoor heat exchanger 3 from first expansion valve 4. Refrigerant that has evaporated in outdoor heat exchanger 3 flows through first four-way valve 2 into the inlet of compressor 1.
- FIG. 6 and 7 A construction of indoor unit 102 of air-conditioner 100 according to the first embodiment will now be described with reference to Figs. 6 and 7 .
- a solid arrow shows a flow of refrigerant and a hollow arrow shows a flow of air.
- the construction of indoor unit 102 shown Figs. 6 and 7 is by way of example, and not limited as such.
- Indoor unit 102 includes a housing 102a.
- An inlet 102b for intake of air is provided in a front surface and an upper surface of housing 102a.
- An outlet 102c for blowing air is provided in a lower surface of housing 102a.
- First heat exchange portion 7a is arranged such that air suctioned through inlet 102b passes therethrough before air passes through second heat exchange portion 7b.
- Second heat exchange portion 7b is arranged such that air that has passed through first heat exchange portion 7a passes therethrough.
- Indoor fan 10 is arranged in the rear of second heat exchange portion 7b.
- a cross flow fan is employed as indoor fan 10. Air that has passed through first heat exchange portion 7a, second heat exchange portion 7b, and indoor fan 10 is blown indoors through outlet 102c.
- first heat exchange portion 7a the flow of refrigerant with respect to the flow of air is the parallel flow. Therefore, in first heat exchange portion 7a that functions as the evaporator during the reheating dehumidification operation, the flow of refrigerant with respect to the flow of air can be the parallel flow. Air can thus efficiently be cooled in first heat exchange portion 7a. Therefore, sufficient dehumidification can be achieved in the reheating dehumidification operation.
- the cooling operation in which a sensible heat factor (SHF) is controlled can be performed owing to the reheating dehumidification operation.
- SHF sensible heat factor
- first heat exchange portion 7a that functions as the evaporator during the reheating dehumidification operation and second heat exchange portion 7b that functions as the condenser during the reheating dehumidification operation are arranged along the direction of flow of air, air does not have to separately be sent to first heat exchange portion 7a and second heat exchange portion 7b. Therefore, increase in input to indoor fan 10 can be suppressed.
- second heat exchange portion 7b that functions as the condenser, the flow of refrigerant with respect to the flow of air is the counterflow. Therefore, performance of the condenser can be improved.
- Air-conditioner 100 according to a second embodiment is identical in construction, operations, and function and effect to air-conditioner 100 according to the first embodiment, unless particularly described.
- Air-conditioner 100 according to the second embodiment is different from air-conditioner 100 according to the first embodiment in position of second four-way valve 5.
- Air-conditioner 100 according to the second embodiment will be described with reference to Figs. 8 to 10 .
- second four-way valve 5 is accommodated in indoor unit 102.
- Refrigerant circuit RC has first extension pipe P1 and second extension pipe P2.
- First extension pipe P1 connects first expansion valve 4 and second four-way valve 5 to each other.
- Second extension pipe P2 connects first four-way valve 2 and second four-way valve 5 to each other.
- First extension pipe P1 is smaller in inner diameter than second extension pipe P2.
- air-conditioner 100 according to the second embodiment operates in the cooling operation, the reheating dehumidification operation, and the heating operation similarly to air-conditioner 100 according to the first embodiment.
- air-conditioner 100 according to the second embodiment A function and effect of air-conditioner 100 according to the second embodiment will now be described as compared with air-conditioner 100 according to the first embodiment.
- air-conditioner 100 during the cooling operation, low-pressure gas-liquid two-phase refrigerant throttled down by first expansion valve 4 that contains much liquid phase flows into first extension pipe P1 and refrigerant flows into indoor unit 102.
- low-pressure gas refrigerant that has exchanged heat in indoor unit 102 flows into first extension pipe P1.
- First extension pipe P1 is smaller in inner diameter than second extension pipe P2, in expectation of flow of liquid refrigerant or gas-liquid two-phase refrigerant that contains much liquid phase.
- gas refrigerant flows into first extension pipe P1 during the reheating dehumidification operation. Since the flow velocity of refrigerant is thus higher than that in an example where liquid-phase refrigerant flows, the pressure loss of refrigerant that occurs in the pipe increases.
- first extension pipe P1 connects first expansion valve 4 and second four-way valve 5 to each other.
- Second extension pipe P2 connects first four-way valve 2 and second four-way valve 5 to each other.
- First extension pipe P1 is smaller in inner diameter than second extension pipe P2. Therefore, in both of the cooling operation and the reheating dehumidification operation, gas-liquid two-phase refrigerant throttled down by first expansion valve 4 flows into first extension pipe P1. Therefore, occurrence of the pressure loss of refrigerant can be suppressed as compared with the pressure loss in an example where gas refrigerant flows through first extension pipe P1 in the reheating dehumidification operation.
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Abstract
Description
- The present disclosure relates to an air-conditioner.
- An air-conditioner capable of performing both of a cooling operation and a reheating dehumidification operation has conventionally been proposed. Such an air-conditioner is described, for example, in
Japanese Patent Laying-Open No. 2020-125855 - PTL 1:
Japanese Patent Laying-Open No. 2020-125855 - A heat exchanger is normally designed such that, when the heat exchanger is used as an evaporator, air that flows on the outside of the heat exchanger and refrigerant that flows in the inside of the heat exchanger are parallel flows with orientations thereof being the same, for the following reason. In an evaporator where low-pressure gas-liquid two-phase refrigerant or gas-phase refrigerant flows, a density of refrigerant is low and a flow velocity of refrigerant is high. Therefore, pressure loss in the evaporator is greater than pressure loss in a condenser. Accordingly, a saturation temperature at an outlet of the evaporator is lower than a saturation temperature at an inlet of the evaporator. Therefore, in an example where air and refrigerant flow as parallel flows, a temperature of refrigerant becomes lower with cooling of air, and hence the temperature at the outlet is lower than in an example where air and refrigerant flow as counterflows. Air can thus efficiently be cooled.
- In a reheating dehumidification operation of the air-conditioner described in the literature, in each of the plurality of heat exchange portions of the indoor heat exchanger, air and refrigerant flow as counterflows. Therefore, also in the heat exchange portion used also as the evaporator, air and refrigerant flow as counterflows. Since air can thus not efficiently be cooled, sufficient dehumidification cannot be achieved.
- The present disclosure was made in view of the problems above, and an object thereof is to provide an air-conditioner capable of sufficient dehumidification in a reheating dehumidification operation.
- An air-conditioner in the present disclosure is provided with a refrigerant circuit and an indoor fan. The refrigerant circuit has a compressor, a first four-way valve, an outdoor heat exchanger, a first expansion valve, a second four-way valve, a third four-way valve, an indoor heat exchanger, and a second expansion valve, and is configured to circulate refrigerant. The indoor fan is configured to send air to the indoor heat exchanger. The indoor heat exchanger has a first heat exchange portion and a second heat exchange portion. The first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second expansion valve, the second heat exchange portion, the second four-way valve, and the first four-way valve during a cooling operation. The first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the second heat exchange portion, the second expansion valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second four-way valve, and the first four-way valve during a reheating dehumidification operation. During the cooling operation, in the first heat exchange portion and the second heat exchange portion, a flow of refrigerant with respect to a flow of air sent by the indoor fan is a parallel flow. During the reheating dehumidification operation, in the first heat exchange portion, the flow of refrigerant with respect to the flow of air is a parallel flow, and in the second heat exchange portion, the flow of refrigerant with respect to the flow of air is a counterflow.
- According to the present disclosure, during the reheating dehumidification operation, in the first heat exchange portion, the flow of refrigerant with respect to the flow of air is the parallel flow. Therefore, sufficient dehumidification can be achieved in the reheating dehumidification operation.
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Fig. 1 is a diagram of a refrigerant circuit during a cooling operation of an air-conditioner according to a first embodiment. -
Fig. 2 is a pressure-enthalpy diagram during the cooling operation of the air-conditioner according to the first embodiment. -
Fig. 3 is a diagram of the refrigerant circuit during a reheating dehumidification operation of the air-conditioner according to the first embodiment. -
Fig. 4 is a pressure-enthalpy diagram during the reheating dehumidification operation of the air-conditioner according to the first embodiment. -
Fig. 5 is a diagram of the refrigerant circuit during a heating operation of the air-conditioner according to the first embodiment. -
Fig. 6 is a cross-sectional view schematically showing a construction during the cooling operation, of an indoor unit of the air-conditioner according to the first embodiment. -
Fig. 7 is a cross-sectional view schematically showing a construction during the reheating dehumidification operation, of the indoor unit of the air-conditioner according to the first embodiment. -
Fig. 8 is a diagram of the refrigerant circuit during the cooling operation of the air-conditioner according to a second embodiment. -
Fig. 9 is a diagram of the refrigerant circuit during the reheating dehumidification operation of the air-conditioner according to the second embodiment. -
Fig. 10 is a diagram of the refrigerant circuit during the heating operation of the air-conditioner according to the second embodiment. - An embodiment will be described below with reference to the drawings. The same or corresponding elements below have the same reference characters allotted and description thereof will not be repeated.
- A construction of an air-
conditioner 100 according to a first embodiment will be described with reference toFig. 1 . - As shown in
Fig. 1 , air-conditioner 100 is provided with a refrigerant circuit RC, anoutdoor fan 9, anindoor fan 10, and acontrol device 11. Refrigerant circuit RC has acompressor 1, a first four-way valve 2, anoutdoor heat exchanger 3, afirst expansion valve 4, a second four-way valve 5, a third four-way valve 6, anindoor heat exchanger 7, asecond expansion valve 8, and a pipe P.Indoor heat exchanger 7 has a firstheat exchange portion 7a and a secondheat exchange portion 7b. Pipe P includes a first extension pipe P1 and a second extension pipe P2. - Refrigerant circuit RC is constructed by connection of
compressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5, third four-way valve 6,indoor heat exchanger 7, andsecond expansion valve 8 through pipe P. Refrigerant circuit RC is constructed to circulate refrigerant. - Air-
conditioner 100 includes anoutdoor unit 101 and anindoor unit 102.Outdoor unit 101 andindoor unit 102 are connected to each other through first extension pipe P1 and second extension pipe P2.Compressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5,outdoor fan 9, andcontrol device 11 are accommodated inoutdoor unit 101. Third four-way valve 6,indoor heat exchanger 7,second expansion valve 8, andindoor fan 10 are accommodated inindoor unit 102. -
Compressor 1 is constructed to compress refrigerant.Compressor 1 is constructed to compress and discharge suctioned refrigerant.Compressor 1 is, for example, of a variable displacement type.Compressor 1 is constructed as being variable in capacity, for example, by adjustment of the number of rotations ofcompressor 1 based on an instruction fromcontrol device 11. - First four-
way valve 2 is connected to an inlet and an outlet ofcompressor 1,outdoor heat exchanger 3, and second four-way valve 5. First four-way valve 2 is constructed to switch a flow of refrigerant such that refrigerant compressed bycompressor 1 flows tooutdoor heat exchanger 3 orindoor heat exchanger 7. When first four-way valve 2 switches the flow of refrigerant such that refrigerant compressed bycompressor 1 flows toindoor heat exchanger 7, refrigerant flows from first four-way valve 2 through second four-way valve 5 toindoor heat exchanger 7. - First four-
way valve 2 is constructed to allow refrigerant discharged fromcompressor 1 to flow tooutdoor heat exchanger 3 during a cooling operation and a reheating dehumidification operation. First four-way valve 2 is constructed to allow refrigerant discharged fromcompressor 1 to flow toindoor heat exchanger 7 during a heating operation. -
Outdoor heat exchanger 3 is constructed to exchange heat between refrigerant that flows in the inside ofoutdoor heat exchanger 3 and air that flows on the outside ofoutdoor heat exchanger 3.Outdoor heat exchanger 3 is constructed to function as a condenser that condenses refrigerant during the cooling operation and the reheating dehumidification operation.Outdoor heat exchanger 3 is constructed to function as an evaporator that evaporates refrigerant during the heating operation.Outdoor heat exchanger 3 is, for example, a finned tube heat exchanger having a plurality of fins and a heat transfer tube that passes through the plurality of fins. -
First expansion valve 4 is constructed to decompress by expanding, refrigerant condensed by the condenser.First expansion valve 4 is constructed to decompress refrigerant condensed byoutdoor heat exchanger 3 during the cooling operation and the reheating dehumidification operation.First expansion valve 4 is constructed to decompress refrigerant condensed byindoor heat exchanger 7 during the heating operation. For example, a solenoid expansion valve is employed as the first expansion valve. - Second four-
way valve 5 is connected to first four-way valve 2,first expansion valve 4, third four-way valve 6, and secondheat exchange portion 7b ofindoor heat exchanger 7. Second four-way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that flows out offirst expansion valve 4 flows through third four-way valve 6 to firstheat exchange portion 7a ofindoor heat exchanger 7 and refrigerant that flows out of secondheat exchange portion 7b ofindoor heat exchanger 7 flows to first four-way valve 2 during the cooling operation. - Second four-
way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that flows out offirst expansion valve 4 flows to secondheat exchange portion 7b ofindoor heat exchanger 7 and refrigerant that flows out of firstheat exchange portion 7a ofindoor heat exchanger 7 and passes through third four-way valve 6 flows to first four-way valve 2 during the reheating dehumidification operation. - Second four-
way valve 5 is constructed to switch the flow of refrigerant such that refrigerant that is discharged fromcompressor 1 and passes through first four-way valve 2 flows to secondheat exchange portion 7b ofindoor heat exchanger 7 and refrigerant that flows out of firstheat exchange portion 7a ofindoor heat exchanger 7 and passes through third four-way valve 6 flows tofirst expansion valve 4 during the heating operation. - Third four-
way valve 6 is connected to second four-way valve 5, an inlet and an outlet of firstheat exchange portion 7a ofindoor heat exchanger 7, andsecond expansion valve 8. Third four-way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out of second four-way valve 5 flows to a heat transfer tube on a windward side of firstheat exchange portion 7a and refrigerant that flows out of a heat transfer tube on a leeward side of firstheat exchange portion 7a flows throughsecond expansion valve 8 to a heat transfer tube on the windward side of secondheat exchange portion 7b ofindoor heat exchanger 7 during the cooling operation. - Third four-
way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out ofsecond expansion valve 8 flows to the heat transfer tube on the windward side of firstheat exchange portion 7a and refrigerant that flows out of the heat transfer tube on the leeward side of firstheat exchange portion 7a flows to second four-way valve 5 during the reheating dehumidification operation. - Third four-
way valve 6 is constructed to switch the flow of refrigerant such that refrigerant that flows out ofsecond expansion valve 8 flows to the heat transfer tube on the leeward side of firstheat exchange portion 7a and refrigerant that flows out of the heat transfer tube on the windward side of firstheat exchange portion 7a flows to second four-way valve 5 during the heating operation. -
Indoor heat exchanger 7 is constructed to exchange heat between refrigerant that flows in the inside ofindoor heat exchanger 7 and air that flows on the outside ofindoor heat exchanger 7.Indoor heat exchanger 7 is constructed to function as the evaporator that evaporates refrigerant during the cooling operation. Both of firstheat exchange portion 7a and secondheat exchange portion 7b are constructed to function as the evaporator that evaporates refrigerant during the cooling operation. -
Indoor heat exchanger 7 is constructed to function as the evaporator that evaporates refrigerant and the condenser that condenses refrigerant during the reheating dehumidification operation. Firstheat exchange portion 7a is constructed to function as the evaporator that evaporates refrigerant during the reheating dehumidification operation. Secondheat exchange portion 7b is constructed to function as the condenser that condenses refrigerant during the reheating dehumidification operation. -
Indoor heat exchanger 7 is constructed to function as the condenser that condenses refrigerant during the heating operation. Both of firstheat exchange portion 7a and secondheat exchange portion 7b are constructed to function as the condenser that condenses refrigerant during the heating operation. -
Indoor heat exchanger 7 is, for example, a finned tube heat exchanger having a plurality of fins and a heat transfer tube that passes through the plurality of fins. - First
heat exchange portion 7a and secondheat exchange portion 7b are arranged as being aligned in a direction of flow of air sent byindoor fan 10. Firstheat exchange portion 7a is arranged on the windward side relative to secondheat exchange portion 7b in the flow of air sent byindoor fan 10. Secondheat exchange portion 7b is arranged on the leeward side relative to firstheat exchange portion 7a in the flow of air sent byindoor fan 10. - First
heat exchange portion 7a has the heat transfer tube on the windward side and the heat transfer tube on the leeward side. The heat transfer tube on the windward side is connected to the heat transfer tube of the leeward side. Firstheat exchange portion 7a is constructed such that refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side during the cooling operation and the reheating dehumidification operation. During the cooling operation and the reheating dehumidification operation, refrigerant and air that flow in firstheat exchange portion 7a flow as parallel flows. Firstheat exchange portion 7a is constructed such that refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side during the heating operation. During the heating operation, refrigerant and air that flow in firstheat exchange portion 7a flow as counterflows. - Second
heat exchange portion 7b has the heat transfer tube on the windward side and a heat transfer tube on the leeward side. The heat transfer tube on the windward side is connected to the heat transfer tube on the leeward side. Secondheat exchange portion 7b is constructed such that refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side during the cooling operation. During the cooling operation, refrigerant and air that flow in secondheat exchange portion 7b flow as parallel flows. Secondheat exchange portion 7b is constructed such that refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side during the reheating dehumidification operation and the heating operation. During the reheating dehumidification operation and the heating operation, refrigerant and air that flow in secondheat exchange portion 7b flow as counterflows. -
Second expansion valve 8 is constructed to decompress refrigerant condensed in secondheat exchange portion 7b ofindoor heat exchanger 7 during the reheating dehumidification operation.Second expansion valve 8 is constructed to suppress decompression of refrigerant by increasing an opening of the valve during the cooling operation and the heating operation. For example, a solenoid expansion valve is employed assecond expansion valve 8. - First four-
way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5, third four-way valve 6, firstheat exchange portion 7a, third four-way valve 6,second expansion valve 8, secondheat exchange portion 7b, second four-way valve 5, and first four-way valve 2 during the cooling operation. - First four-
way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5, secondheat exchange portion 7b,second expansion valve 8, third four-way valve 6, firstheat exchange portion 7a, third four-way valve 6, second four-way valve 5, and first four-way valve 2 during the reheating dehumidification operation. - First four-
way valve 2, second four-way valve 5, and third four-way valve 6 are switched such that refrigerant flows through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2, second four-way valve 5, secondheat exchange portion 7b,second expansion valve 8, third four-way valve 6, firstheat exchange portion 7a, third four-way valve 6, second four-way valve 5,first expansion valve 4,outdoor heat exchanger 3, and first four-way valve 2 during the heating operation. -
Outdoor fan 9 is constructed to send air tooutdoor heat exchanger 3. In other words,outdoor fan 9 is constructed to supply outdoor air tooutdoor heat exchanger 3. -
Indoor fan 10 is constructed to send air toindoor heat exchanger 7. In other words,indoor fan 10 is constructed to supply indoor air toindoor heat exchanger 7. - During the cooling operation, in first
heat exchange portion 7a and secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air sent byindoor fan 10 is the parallel flow. During the reheating dehumidification operation, in firstheat exchange portion 7a, the flow of refrigerant with respect to the flow of air sent byindoor fan 10 is the parallel flow, and in secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the counterflow. During the heating operation, in firstheat exchange portion 7a and secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air sent byindoor fan 10 is the counterflow. -
Control device 11 is configured to control each device in air-conditioner 100 by performing computation and giving an instruction.Control device 11 is electrically connected tocompressor 1, first four-way valve 2,first expansion valve 4, second four-way valve 5, third four-way valve 6,second expansion valve 8,outdoor fan 9,indoor fan 10, and the like and configured to control operations thereof. - Operations of air-
conditioner 100 according to the first embodiment will now be described with reference toFigs. 1 to 5 . InFigs. 1 to 5 , a solid arrow shows a flow of refrigerant and a hollow arrow shows a flow of air. Air-conditioner 100 according to the first embodiment can selectively perform the cooling operation, the reheating dehumidification operation, and the heating operation. - The cooling operation performed by air-
conditioner 100 will be described with reference toFigs. 1 and2 . During the cooling operation, refrigerant circulates through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5, third four-way valve 6, firstheat exchange portion 7a ofindoor heat exchanger 7, third four-way valve 6,second expansion valve 8, secondheat exchange portion 7b ofindoor heat exchanger 7, second four-way valve 5, and first four-way valve 2. - High-pressure gas refrigerant discharged from
compressor 1 flows intooutdoor heat exchanger 3 through first four-way valve 2. Inoutdoor heat exchanger 3, heat is exchanged between high-pressure gas refrigerant and air sent byoutdoor fan 9, so that refrigerant radiates heat and changes to liquid refrigerant. Liquid refrigerant flows fromoutdoor heat exchanger 3 intofirst expansion valve 4. Infirst expansion valve 4, liquid refrigerant is decompressed and becomes gas-liquid two-phase refrigerant. - Gas-liquid two-phase refrigerant flows into second four-
way valve 5 fromfirst expansion valve 4. In the cooling operation, a flow path in second four-way valve 5 is switched to connectfirst expansion valve 4 and first extension pipe P1 to each other. Gas-liquid two-phase refrigerant passes through first extension pipe P1 from second four-way valve 5 and flows into third four-way valve 6. In third four-way valve 6, the flow path is switched to connect first extension pipe P1 and the heat transfer tube on the windward side of firstheat exchange portion 7a ofindoor heat exchanger 7 to each other. - Heat is exchanged between refrigerant that flows into the heat transfer tube on the windward side of first
heat exchange portion 7a ofindoor heat exchanger 7 and air sent byindoor fan 10 and thereafter refrigerant flows out of the heat transfer tube on the leeward side of firstheat exchange portion 7a. At this time, air that flows on the outside of firstheat exchange portion 7a and refrigerant that flows in the inside of firstheat exchange portion 7a are in the same orientation. In other words, in firstheat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the parallel flow. - Refrigerant flows again into third four-
way valve 6 from firstheat exchange portion 7a and thereafter flows intosecond expansion valve 8. In the cooling operation, the opening ofsecond expansion valve 8 is set to increase. Therefore, since the pressure loss of refrigerant is less likely insecond expansion valve 8, refrigerant flows as it is into the heat transfer tube on the windward side of secondheat exchange portion 7b ofindoor heat exchanger 7 fromsecond expansion valve 8. - Air cooled in first
heat exchange portion 7a is sent to secondheat exchange portion 7b. At this time, air that flows on the outside of secondheat exchange portion 7b and refrigerant that flows in the inside of secondheat exchange portion 7b are in the same orientation. In other words, in secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the parallel flow. - Gas refrigerant that has evaporated in second
heat exchange portion 7b flows from secondheat exchange portion 7b through second extension pipe P2 into second four-way valve 5. In second four-way valve 5, the flow path is switched to connect second extension pipe P2 and first four-way valve 2 to each other. Gas refrigerant flows from second four-way valve 5 through first four-way valve 2 into the inlet ofcompressor 1. - The reheating dehumidification operation performed by air-
conditioner 100 will be described with reference toFigs. 3 and4 . During the reheating dehumidification operation, refrigerant circulates through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2,outdoor heat exchanger 3,first expansion valve 4, second four-way valve 5, secondheat exchange portion 7b ofindoor heat exchanger 7,second expansion valve 8, third four-way valve 6, firstheat exchange portion 7a ofindoor heat exchanger 7, third four-way valve 6, second four-way valve 5, and first four-way valve 2. - In the reheating dehumidification operation, second four-
way valve 5 and third four-way valve 6 are switched from a state thereof in the cooling operation shown inFig. 1 . Liquid refrigerant that has exchanged heat with air sent byoutdoor fan 9 inoutdoor heat exchanger 3 flows intofirst expansion valve 4. At this time, by increasing the opening offirst expansion valve 4 as compared with the opening during the cooling operation, the temperature of refrigerant at an outlet offirst expansion valve 4 can be higher than the temperature of indoor air. Refrigerant flows fromfirst expansion valve 4 into second four-way valve 5. - In the reheating dehumidification operation, the flow path in second four-
way valve 5 is switched to connectfirst expansion valve 4 and second extension pipe P2 to each other. Refrigerant passes through second extension pipe P2 from second four-way valve 5 and flows into secondheat exchange portion 7b ofindoor heat exchanger 7. Refrigerant flows from the heat transfer tube on the leeward side to the heat transfer tube on the windward side in secondheat exchange portion 7b ofindoor heat exchanger 7. In secondheat exchange portion 7b, refrigerant heats air cooled in firstheat exchange portion 7a. At this time, air that flows on the outside of secondheat exchange portion 7b and refrigerant that flows in the inside of secondheat exchange portion 7b are in orientations reverse to each other. In other words, in secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the counterflow. - Refrigerant flows into
second expansion valve 8 from secondheat exchange portion 7b. Refrigerant is decompressed insecond expansion valve 8 and thereafter flows into third four-way valve 6. Refrigerant flows from third four-way valve 6 into the heat transfer tube on the windward side of firstheat exchange portion 7a. Refrigerant flows from the heat transfer tube on the windward side to the heat transfer tube on the leeward side in firstheat exchange portion 7a. Refrigerant cools air in firstheat exchange portion 7a. At this time, air that flows on the outside of firstheat exchange portion 7a and refrigerant that flows in the inside of firstheat exchange portion 7a are in the same orientation. In other words, in firstheat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the parallel flow. - Refrigerant that has cooled indoor air flows again into third four-
way valve 6 from firstheat exchange portion 7a and then passes through first extension pipe P1 and flows into second four-way valve 5. In second four-way valve 5, the flow path is switched to connect first extension pipe P1 and first four-way valve 2 to each other. Refrigerant flows from second four-way valve 5 through first four-way valve 2 into the inlet ofcompressor 1. - The heating operation performed by air-
conditioner 100 will be described with reference toFig. 5 . During the heating operation, refrigerant circulates through refrigerant circuit RC in the order ofcompressor 1, first four-way valve 2, second four-way valve 5, secondheat exchange portion 7b ofindoor heat exchanger 7,second expansion valve 8, third four-way valve 6, firstheat exchange portion 7a ofindoor heat exchanger 7, third four-way valve 6, second four-way valve 5,first expansion valve 4,outdoor heat exchanger 3, and first four-way valve 2. - During the heating operation, first four-
way valve 2 is switched from the state thereof in the cooling operation shown inFig. 1 . High-pressure gas refrigerant discharged fromcompressor 1 flows through first four-way valve 2 and second four-way valve 5 into secondheat exchange portion 7b ofindoor heat exchanger 7. Refrigerant is condensed in secondheat exchange portion 7b. Air that flows on the outside of secondheat exchange portion 7b and refrigerant that flows in the inside of secondheat exchange portion 7b are in orientations reverse to each other. In other words, in secondheat exchange portion 7b, the flow of refrigerant with respect to the flow of air is the counterflow. - Refrigerant flows into
second expansion valve 8 from secondheat exchange portion 7b. In the heating operation, the opening ofsecond expansion valve 8 is set to increase. Refrigerant flows fromsecond expansion valve 8 through third four-way valve 6 into firstheat exchange portion 7a ofindoor heat exchanger 7. Refrigerant is condensed in firstheat exchange portion 7a. Air that flows on the outside of firstheat exchange portion 7a and refrigerant that flows in the inside of firstheat exchange portion 7a are in orientations reverse to each other. In other words, in firstheat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the counterflow. - Refrigerant flows from first
heat exchange portion 7a through third four-way valve 6 and second four-way valve 5 intofirst expansion valve 4. Refrigerant is decompressed infirst expansion valve 4. Refrigerant flows intooutdoor heat exchanger 3 fromfirst expansion valve 4. Refrigerant that has evaporated inoutdoor heat exchanger 3 flows through first four-way valve 2 into the inlet ofcompressor 1. - A construction of
indoor unit 102 of air-conditioner 100 according to the first embodiment will now be described with reference toFigs. 6 and7 . InFigs. 6 and7 , a solid arrow shows a flow of refrigerant and a hollow arrow shows a flow of air. The construction ofindoor unit 102 shownFigs. 6 and7 is by way of example, and not limited as such. -
Indoor unit 102 includes ahousing 102a. Aninlet 102b for intake of air is provided in a front surface and an upper surface ofhousing 102a. Anoutlet 102c for blowing air is provided in a lower surface ofhousing 102a. Firstheat exchange portion 7a is arranged such that air suctioned throughinlet 102b passes therethrough before air passes through secondheat exchange portion 7b. Secondheat exchange portion 7b is arranged such that air that has passed through firstheat exchange portion 7a passes therethrough.Indoor fan 10 is arranged in the rear of secondheat exchange portion 7b. For example, a cross flow fan is employed asindoor fan 10. Air that has passed through firstheat exchange portion 7a, secondheat exchange portion 7b, andindoor fan 10 is blown indoors throughoutlet 102c. - A function and effect of air-
conditioner 100 according to the first embodiment will now be described. - According to air-
conditioner 100 according to the first embodiment, during the reheating dehumidification operation, in firstheat exchange portion 7a, the flow of refrigerant with respect to the flow of air is the parallel flow. Therefore, in firstheat exchange portion 7a that functions as the evaporator during the reheating dehumidification operation, the flow of refrigerant with respect to the flow of air can be the parallel flow. Air can thus efficiently be cooled in firstheat exchange portion 7a. Therefore, sufficient dehumidification can be achieved in the reheating dehumidification operation. - In addition, the cooling operation in which a sensible heat factor (SHF) is controlled can be performed owing to the reheating dehumidification operation.
- Since first
heat exchange portion 7a that functions as the evaporator during the reheating dehumidification operation and secondheat exchange portion 7b that functions as the condenser during the reheating dehumidification operation are arranged along the direction of flow of air, air does not have to separately be sent to firstheat exchange portion 7a and secondheat exchange portion 7b. Therefore, increase in input toindoor fan 10 can be suppressed. - Furthermore, during the reheating dehumidification operation, in second
heat exchange portion 7b that functions as the condenser, the flow of refrigerant with respect to the flow of air is the counterflow. Therefore, performance of the condenser can be improved. - Air-
conditioner 100 according to a second embodiment is identical in construction, operations, and function and effect to air-conditioner 100 according to the first embodiment, unless particularly described. - Air-
conditioner 100 according to the second embodiment is different from air-conditioner 100 according to the first embodiment in position of second four-way valve 5. - Air-
conditioner 100 according to the second embodiment will be described with reference toFigs. 8 to 10 . As shown inFig. 8 , in air-conditioner 100 according to the second embodiment, second four-way valve 5 is accommodated inindoor unit 102. Refrigerant circuit RC has first extension pipe P1 and second extension pipe P2. First extension pipe P1 connectsfirst expansion valve 4 and second four-way valve 5 to each other. Second extension pipe P2 connects first four-way valve 2 and second four-way valve 5 to each other. First extension pipe P1 is smaller in inner diameter than second extension pipe P2. - As shown in
Figs. 8 to 10 , air-conditioner 100 according to the second embodiment operates in the cooling operation, the reheating dehumidification operation, and the heating operation similarly to air-conditioner 100 according to the first embodiment. - A function and effect of air-
conditioner 100 according to the second embodiment will now be described as compared with air-conditioner 100 according to the first embodiment. - In air-
conditioner 100 according to the first embodiment, during the cooling operation, low-pressure gas-liquid two-phase refrigerant throttled down byfirst expansion valve 4 that contains much liquid phase flows into first extension pipe P1 and refrigerant flows intoindoor unit 102. During the reheating dehumidification operation, low-pressure gas refrigerant that has exchanged heat inindoor unit 102 flows into first extension pipe P1. First extension pipe P1 is smaller in inner diameter than second extension pipe P2, in expectation of flow of liquid refrigerant or gas-liquid two-phase refrigerant that contains much liquid phase. In the first embodiment, gas refrigerant flows into first extension pipe P1 during the reheating dehumidification operation. Since the flow velocity of refrigerant is thus higher than that in an example where liquid-phase refrigerant flows, the pressure loss of refrigerant that occurs in the pipe increases. - According to air-
conditioner 100 according to the second embodiment, first extension pipe P1 connectsfirst expansion valve 4 and second four-way valve 5 to each other. Second extension pipe P2 connects first four-way valve 2 and second four-way valve 5 to each other. First extension pipe P1 is smaller in inner diameter than second extension pipe P2. Therefore, in both of the cooling operation and the reheating dehumidification operation, gas-liquid two-phase refrigerant throttled down byfirst expansion valve 4 flows into first extension pipe P1. Therefore, occurrence of the pressure loss of refrigerant can be suppressed as compared with the pressure loss in an example where gas refrigerant flows through first extension pipe P1 in the reheating dehumidification operation. - It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the terms of the claims rather than the description above and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
- 1 compressor; 2 first four-way valve; 3 outdoor heat exchanger; 4 first expansion valve; 5 second four-way valve; 6 third four-way valve; 7 indoor heat exchanger; 7a first heat exchange portion; 7b second heat exchange portion; 8 second expansion valve; 9 outdoor fan; 10 indoor fan; 11 control device; 100 air-conditioner; 101 outdoor unit; 102 indoor unit; 102a housing; 102b inlet; 102c outlet; P pipe; P1 first extension pipe; P2 second extension pipe; RC refrigerant circuit
Claims (2)
- An air-conditioner comprising:a refrigerant circuit having a compressor, a first four-way valve, an outdoor heat exchanger, a first expansion valve, a second four-way valve, a third four-way valve, an indoor heat exchanger, and a second expansion valve, the refrigerant circuit being configured to circulate refrigerant; andan indoor fan configured to send air to the indoor heat exchanger, whereinthe indoor heat exchanger has a first heat exchange portion and a second heat exchange portion,the first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second expansion valve, the second heat exchange portion, the second four-way valve, and the first four-way valve during a cooling operation,the first four-way valve, the second four-way valve, and the third four-way valve are switched to allow refrigerant to flow through the refrigerant circuit in an order of the compressor, the first four-way valve, the outdoor heat exchanger, the first expansion valve, the second four-way valve, the second heat exchange portion, the second expansion valve, the third four-way valve, the first heat exchange portion, the third four-way valve, the second four-way valve, and the first four-way valve during a reheating dehumidification operation,during the cooling operation, in the first heat exchange portion and the second heat exchange portion, a flow of refrigerant with respect to a flow of air sent by the indoor fan is a parallel flow, andduring the reheating dehumidification operation, in the first heat exchange portion, the flow of refrigerant with respect to the flow of air is a parallel flow, and in the second heat exchange portion, the flow of refrigerant with respect to the flow of air is a counterflow.
- The air-conditioner according to claim 1, whereinthe refrigerant circuit has a first extension pipe that connects the first expansion valve and the second four-way valve to each other and a second extension pipe that connects the first four-way valve and the second four-way valve to each other, andthe first extension pipe is smaller in inner diameter than the second extension pipe.
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PCT/JP2021/014805 WO2022215204A1 (en) | 2021-04-07 | 2021-04-07 | Air conditioner |
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EP4321820A1 true EP4321820A1 (en) | 2024-02-14 |
EP4321820A4 EP4321820A4 (en) | 2024-05-29 |
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EP21936008.8A Pending EP4321820A4 (en) | 2021-04-07 | 2021-04-07 | Air conditioner |
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US (1) | US20240151425A1 (en) |
EP (1) | EP4321820A4 (en) |
JP (1) | JP7450807B2 (en) |
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JPS5322994Y2 (en) * | 1973-09-28 | 1978-06-14 | ||
JP5060840B2 (en) | 2007-06-20 | 2012-10-31 | 矢崎総業株式会社 | Luminous pointer instrument |
JP4989420B2 (en) * | 2007-10-29 | 2012-08-01 | 日立アプライアンス株式会社 | Air conditioner |
JP2020125855A (en) | 2019-02-01 | 2020-08-20 | ダイキン工業株式会社 | Air conditioner |
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2021
- 2021-04-07 CN CN202180096528.1A patent/CN117083492A/en active Pending
- 2021-04-07 EP EP21936008.8A patent/EP4321820A4/en active Pending
- 2021-04-07 US US18/549,229 patent/US20240151425A1/en active Pending
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WO2022215204A1 (en) | 2022-10-13 |
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JPWO2022215204A1 (en) | 2022-10-13 |
CN117083492A (en) | 2023-11-17 |
JP7450807B2 (en) | 2024-03-15 |
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