US20230147134A1 - Heat exchanger and air-conditioning apparatus - Google Patents
Heat exchanger and air-conditioning apparatus Download PDFInfo
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- US20230147134A1 US20230147134A1 US17/910,914 US202017910914A US2023147134A1 US 20230147134 A1 US20230147134 A1 US 20230147134A1 US 202017910914 A US202017910914 A US 202017910914A US 2023147134 A1 US2023147134 A1 US 2023147134A1
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- 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
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- 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
- F28D1/053—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 straight
- F28D1/0535—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 straight the conduits having a non-circular cross-section
- F28D1/05366—Assemblies of conduits connected to common headers, e.g. core type radiators
- F28D1/05391—Assemblies of conduits connected to common headers, e.g. core type radiators with multiple rows of conduits or with multi-channel conduits combined with a particular flow pattern, e.g. multi-row multi-stage radiators
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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
- 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
- F25B39/00—Evaporators; Condensers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B39/00—Evaporators; Condensers
- F25B39/02—Evaporators
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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
- F25B39/00—Evaporators; Condensers
- F25B39/04—Condensers
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- 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
- F28D1/0417—Multi-circuit heat exchangers, e.g. integrating different heat exchange sections in the same unit or heat exchangers for more than two fluids with particular circuits for the same heat exchange medium, e.g. with the heat exchange medium flowing through sections having different heat exchange capacities or for heating/cooling the heat exchange medium at different temperatures
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/02—Tubular elements of cross-section which is non-circular
- F28F1/022—Tubular elements of cross-section which is non-circular with multiple channels
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
- F28F1/126—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element consisting of zig-zag shaped fins
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
- F28F1/14—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending longitudinally
- F28F1/22—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending longitudinally the means having portions engaging further tubular elements
-
- 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
- F28F9/0202—Header boxes having their inner space divided by partitions
- F28F9/0204—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions
- F28F9/0209—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only transversal partitions
- F28F9/0212—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only transversal partitions the partitions being separate elements attached to header boxes
-
- 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
- F28F9/0202—Header boxes having their inner space divided by partitions
- F28F9/0204—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions
- F28F9/0214—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only longitudinal partitions
-
- 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
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
- F28D2021/0061—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for phase-change applications
-
- 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
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
- F28D2021/0061—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for phase-change applications
- F28D2021/0064—Vaporizers, e.g. evaporators
Definitions
- the present disclosure relates to a heat exchanger including heat transfer tubes, and also relates to an air-conditioning apparatus including the heat exchanger.
- Patent Literature 1 discloses a heat exchanger in which a value of the ratio, obtained by dividing the cross-sectional area of flow passages of a single heat transfer tube by the cross-sectional area of the header per the single heat transfer tube, ranges from 3% to 30%. Patent Literature 1 applies this ratio to the heat exchanger to improve its heat exchange performance.
- Patent Literature 1 in the heat exchanger with a relatively large number of heat transfer tubes, when a low air conditioning load is applied to the heat exchanger, and thus a refrigerant flow rate is relatively low, then refrigerant in a two-phase gas-liquid state may not be able to flow upward inside the heat transfer tubes, but may flow backward. In Patent Literature 1, there is a possibility that this back flow may cause pressure loss inside the heat transfer tubes, and consequently heat exchange performance may be degraded.
- the present disclosure has been achieved to solve the above problems, and it is an object of the present disclosure to provide a heat exchanger and an air-conditioning apparatus including the heat exchanger, in which the heat exchanger reduces the likelihood of the occurrence of pressure loss of refrigerant in heat transfer tubes to improve heat exchange performance.
- a heat exchanger includes a main heat exchanger and a sub-heat exchanger connected to the main heat exchanger.
- the main heat exchanger includes a plurality of main heat transfer tubes extending in an up-down direction, each of the plurality of main heat transfer tubes having a flow passage inside which refrigerant flows, a first main header into which one end portion of each of the plurality of main heat transfer tubes is inserted, main fins provided to the plurality of main heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of main heat transfer tubes, and a second main header into which an other end portion of each of the plurality of main heat transfer tubes is inserted, the second main header being opposite to the first main header.
- the sub-heat exchanger includes a plurality of sub-heat transfer tubes extending in an up-down direction, each of the plurality of sub-heat transfer tubes having a flow passage inside which refrigerant flows, sub-fins provided to the plurality of sub-heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of sub-heat transfer tubes, a first sub-header into which one end portion of each of the plurality of sub-heat transfer tubes is inserted, and a second sub-header into which an other end portion of each of the plurality of sub-heat transfer tubes is inserted, the second sub-header being opposite to the first sub-header.
- the heat exchanger satisfies Expression (1) below, where the number of the plurality of main heat transfer tubes is represented as N 1 , and the number of the plurality of sub-heat transfer tubes is represented as N 2 .
- the heat exchanger satisfies Expressions (2) and (3) below, where a cross-sectional area of the flow passage of each of the plurality of main heat transfer tubes is represented as Ta 1 , a cross-sectional area of the flow passage of each of the plurality of sub-heat transfer tubes is represented as Ta 2 , a cross-sectional area of the first main header per each of the plurality of main heat transfer tubes is represented as Ha 1 , and a cross-sectional area of the first sub-header per each of the plurality of sub-heat transfer tubes is represented as Ha 2 .
- the heat exchanger satisfies Expressions (4) and (5) below, where a sum total of cross-sectional areas of the flow passages of the plurality of main heat transfer tubes is represented as AT 1 , a sum total of cross-sectional areas of the flow passages of the plurality of sub-heat transfer tubes is represented as AT 2 , a flow rate [kG/h] of all refrigerant flowing through the main heat exchanger is represented as Gr 1 , a flow rate [kG/h] of all refrigerant flowing through the sub-heat exchanger is represented as Gr 2 , a gravitational acceleration [m/s 2 ] is represented as G, an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of main heat transfer tubes is represented as D 1 , an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of sub-heat transfer tubes is represented as D 2 , a density [kG/m 3 ] of liquid refrigerant flowing in the pluralit
- the relationship between the number of the main heat transfer tubes and the number of the sub-heat transfer tubes satisfies Expression (1) below.
- the main heat exchanger satisfies Expressions (2) and (4) below, while the sub-heat exchanger satisfies Expressions (3) and (5) below.
- the likelihood of stagnation and back flow of refrigerant is thus reduced when the refrigerant flows upward in the heat transfer tubes. Therefore, the heat exchanger has improved heat exchange performance without causing pressure loss of refrigerant in the heat transfer tubes.
- FIG. 1 is a circuit diagram illustrating an air-conditioning apparatus 1 according to Embodiment 1.
- FIG. 2 is a perspective view illustrating a heat exchanger 7 according to Embodiment 1.
- FIG. 3 is a plan view illustrating the heat exchanger 7 according to Embodiment 1.
- FIG. 4 is a configuration diagram illustrating main heat transfer tubes 31 and a first main header 33 according to Embodiment 1.
- FIG. 5 is a configuration diagram illustrating sub-heat transfer tubes 41 and a first sub-header 43 according to Embodiment 1.
- FIG. 6 is a graph illustrating heat exchange performance of the heat exchanger 7 according to Embodiment 1.
- FIG. 7 is a graph illustrating the conditions under which flooding occurs according to Embodiment 1.
- FIG. 1 is a circuit diagram illustrating the air-conditioning apparatus 1 according to Embodiment 1. As illustrated in FIG. 1 , the air-conditioning apparatus 1 includes an outdoor unit 2 , an indoor unit 3 , and a refrigerant pipe 4 . Note that FIG. 1 illustrates an example in which one indoor unit 3 is provided, however, two or more indoor units 3 may be provided.
- the outdoor unit 2 includes a compressor 5 , a flow switching device 6 , a heat exchanger 7 , an outdoor fan 8 , and an expansion unit 9 .
- the indoor unit 3 includes an indoor heat exchanger 11 and an indoor fan 12 .
- the refrigerant pipe 4 connects the compressor 5 , the flow switching device 6 , the heat exchanger 7 , the expansion unit 9 , and the indoor heat exchanger 11 to form a refrigerant circuit in which refrigerant flows.
- the compressor 5 is configured to suck refrigerant in a low-temperature and low-pressure state, compress the sucked refrigerant into a high-temperature and high-pressure state, and discharge the compressed refrigerant.
- the flow switching device 6 is configured to change the flow directions of refrigerant in the refrigerant circuit.
- the flow switching device 6 is a four-way valve.
- the heat exchanger 7 is configured to exchange heat between refrigerant and outdoor air.
- the heat exchanger 7 operates as a condenser during cooling operation, and operates as an evaporator during heating operation.
- the outdoor fan 8 is a device to deliver outdoor air to the heat exchanger 7 .
- the expansion unit 9 is a pressure reducing valve or an expansion valve to reduce the pressure of refrigerant and expand the refrigerant.
- the indoor heat exchanger 11 is configured to exchange heat between room air and refrigerant.
- the indoor heat exchanger 11 operates as an evaporator during cooling operation, and operates as a condenser during heating operation.
- the indoor fan 12 is a device to deliver room air to the indoor heat exchanger 11 .
- cooling operation is described.
- refrigerant sucked into the compressor 5 is compressed by the compressor 5 into a high-temperature and high-pressure gas state and then discharged.
- the gas refrigerant in a high-temperature and high-pressure state discharged from the compressor 5 passes through the flow switching device 6 and flows into the heat exchanger 7 , which operates as a condenser.
- Refrigerant flowing into the heat exchanger 7 exchanges heat with outdoor air delivered by the outdoor fan 8 , and condenses into liquid.
- the refrigerant in a liquid state flows into the expansion unit 9 , and is reduced in pressure and expanded, so that the refrigerant is brought into a low-temperature and low-pressure two-phase gas-liquid state.
- the refrigerant in the two-phase gas-liquid state flows into the indoor heat exchanger 11 , which operates as an evaporator. Refrigerant flowing into the indoor heat exchanger 11 exchanges heat with room air delivered by the indoor fan 12 , and evaporates into gas. At this time, the room air is cooled and thus cooling is performed in the room. Thereafter, the gas refrigerant having evaporated into a low-temperature and low-pressure state passes through the flow switching device 6 and is sucked into the compressor 5 .
- heating operation is described.
- refrigerant sucked into the compressor 5 is compressed by the compressor 5 into a high-temperature and high-pressure gas state and then discharged.
- the high-temperature and high-pressure gas refrigerant discharged from the compressor 5 passes through the flow switching device 6 and flows into the indoor heat exchanger 11 , which operates as a condenser.
- Refrigerant flowing into the indoor heat exchanger 11 exchanges heat with room air delivered by the indoor fan 12 , and condenses into liquid. At this time, the indoor air is heated and thus heating is performed in the room.
- the refrigerant in a liquid state flows into the expansion unit 9 , and is reduced in pressure and expanded, so that the refrigerant is brought into a low-temperature and low-pressure two-phase gas-liquid state.
- the refrigerant in the two-phase gas-liquid state flows into the heat exchanger 7 , which operates as an evaporator. Refrigerant flowing into the heat exchanger 7 exchanges heat with outdoor air delivered by the outdoor fan 8 , and evaporates into gas. Thereafter, the gas refrigerant having evaporated into a low-temperature and low-pressure state passes through the flow switching device 6 and is sucked into the compressor 5 .
- FIG. 2 is a perspective view illustrating the heat exchanger 7 according to Embodiment 1.
- FIG. 3 is a plan view illustrating the heat exchanger 7 according to Embodiment 1.
- the open arrows illustrated in FIG. 2 represent the flow of refrigerant when the heat exchanger 7 operates as an evaporator.
- the hatched arrow represents the flow of air passing through the heat exchanger 7 .
- the configuration of the heat exchanger 7 is described below in detail. Note that the configuration equivalent to that of the heat exchanger 7 may be applied to the indoor heat exchanger 11 .
- the heat exchanger 7 includes a main heat exchanger 21 and a sub-heat exchanger 22 .
- the main heat exchanger 21 is located upstream of the sub-heat exchanger 22 .
- the sub-heat exchanger 22 operates as a subcooling device.
- the heat exchanger 7 may be formed into an L-shape in top view such that the heat exchanger 7 extends along the back face and the side face of the housing of the outdoor unit 2 .
- a portion of the heat exchanger 7 located beside the back face of the housing, and another portion of the heat exchanger 7 located beside the side face of the housing may be connected through a connection pipe, or may be formed integrally with each other.
- the main heat exchanger 21 includes main heat transfer tubes 31 , main fins 32 , a first main header 33 , a second main header 34 , and a third main header 35 .
- Each of the main heat transfer tubes 31 has a plurality of flow passages inside which refrigerant flows.
- the main heat transfer tubes 31 are flat tubes.
- the main heat transfer tubes 31 extend in the up-down direction.
- the number of the main heat transfer tubes 31 provided in the main heat exchanger 21 is N 1 .
- the main heat transfer tubes 31 are arranged in two parallel lines, which are a first line and a second line. Note that the main heat transfer tubes 31 may be arranged only in a single line.
- Each of the main fins 32 is, for example, a corrugated fin, and the main fins 32 are provided to the main heat transfer tubes 31 and help heat exchange between air and refrigerant flowing inside the main heat transfer tubes 31 .
- each of the main heat transfer tubes 31 arranged in the first line is inserted into the first main header 33 .
- the refrigerant pipe 4 is connected to the first main header 33 .
- the first main header 33 distributes refrigerant flowing from the refrigerant pipe 4 to the main heat transfer tubes 31 arranged in the first line.
- the heat exchanger 7 operates as an evaporator
- the first main header 33 allows refrigerant, having joined together from the main heat transfer tubes 31 arranged in the first line, to flow out to the refrigerant pipe 4 .
- the second main header 34 is provided to be opposite to the first main header 33 and the third main header 35 .
- the other end portion of each of the main heat transfer tubes 31 arranged in the first line and the second line is inserted into the second main header 34 .
- the second main header 34 distributes refrigerant, having joined together from the main heat transfer tubes 31 arranged in the first line, to the main heat transfer tubes 31 arranged in the second line.
- the second main header 34 distributes refrigerant, having joined together from the main heat transfer tubes 31 arranged in the second line, to the main heat transfer tubes 31 arranged in the first line.
- the third main header 35 is provided parallel to the first main header 33 .
- One end portion of each of the main heat transfer tubes 31 arranged in the second line is inserted into the third main header 35 .
- the third main header 35 allows refrigerant, flowing from the main heat transfer tubes 31 arranged in the second line, to flow into the third sub-header 45 of the sub-heat exchanger 22 , which is described later.
- the third main header 35 distributes refrigerant flowing from the third sub-header 45 to the main heat transfer tubes 31 arranged in the second line.
- the first main header 33 and the third main header 35 may be integrated into one header, and the main heat exchanger 21 may include a partition portion (not illustrated) at the central portion of the one header to partition the internal space into sub-spaces.
- FIG. 4 is a configuration diagram illustrating the main heat transfer tubes 31 and the first main header 33 according to Embodiment 1.
- FIG. 4 illustrates the cross-section of the first main header 33 taken along the A-A direction illustrated in FIG. 3 .
- the term “cross-section” refers to a cross-section perpendicular to the direction in which the flow passage formed in the main heat transfer tube 31 extends.
- the equivalent diameter [m] of the cross-section of the flow passage of each of the main heat transfer tubes 31 is represented as D 1 .
- the cross-sectional area of the flow passages of each of the main heat transfer tubes 31 is represented as Ta 1 .
- the cross-sectional area Ta 1 of the flow passages is the sum of the cross-sectional areas of the plurality of flow passages formed in the main heat transfer tube 31 .
- the sum total of the cross-sectional areas of the flow passages of the main heat transfer tubes 31 is represented as AT 1 .
- the sum total AT 1 of the cross-sectional areas of the flow passages refers to a value obtained by multiplying the cross-sectional area Ta 1 of the flow passages of a single main heat transfer tube 31 by the number N 1 of the main heat transfer tubes 31 .
- the cross-sectional area of the first main header 33 per each of the main heat transfer tubes 31 is represented as Ha 1 .
- the cross-sectional area Ha 1 of the first main header 33 per each of the main heat transfer tubes 31 refers to a value obtained by dividing the cross-sectional area of the interior space of the first main header 33 by the number N 1 of the main heat transfer tubes 31 .
- the cross-sectional area Ha 1 of the first main header 33 per each of the main heat transfer tubes 31 refers to the area of the region illustrated in FIG. 4 that is hatched laterally to the sheet plane.
- the main heat exchanger 21 satisfies Expression (2)
- the main heat exchanger 21 also satisfies Expression (4) below, where the flow rate [kG/h] of all refrigerant flowing through the main heat exchanger 21 is represented as Gr 1 , the density [kG/m 3 ] of liquid refrigerant flowing in the main heat transfer tubes 31 is represented as ⁇ L 1 , the density [kG/m 3 ] of gas refrigerant flowing in the main heat transfer tubes 31 is represented as ⁇ G 1 , the quality [ ⁇ ] of refrigerant flowing in the main heat exchanger 21 is represented as X 1 , and the gravitational acceleration [m/s 2 ] is represented as G.
- Expression (4) the flow rate [kG/h] of all refrigerant flowing through the main heat exchanger 21 is represented as Gr 1 , the density [kG/m 3 ] of liquid refrigerant flowing in the main heat transfer tubes 31 is represented as ⁇ L 1 , the density [kG/m 3 ] of gas refrigerant flowing in the main heat transfer tubes 31 is represented as
- the sub-heat exchanger 22 includes sub-heat transfer tubes 41 , sub-fins 42 , a first sub-header 43 , a second sub-header 44 , and a third sub-header 45 .
- Each of the sub-heat transfer tubes 41 has a plurality of flow passages inside which refrigerant flows.
- the sub-heat transfer tubes 41 are flat tubes.
- the sub-heat transfer tubes 41 extend in the up-down direction.
- the number of the sub-heat transfer tubes 41 provided in the sub-heat exchanger 22 is N 2 .
- the sub-heat transfer tubes 41 are arranged in two parallel lines, which are a first line and a second line.
- sub-heat transfer tubes 41 may be arranged only in a single line.
- Each of the sub-fins 42 is, for example, a corrugated fin, and the sub-fins 42 are provided to the sub-heat transfer tubes 41 and help heat exchange between air and refrigerant flowing inside the sub-heat transfer tubes 41 .
- the first sub-header 43 is connected to the first main header 33 through a first partition plate 23 .
- the first partition plate 23 partitions the internal space into the first main header 33 and the first sub-header 43 .
- the refrigerant pipe 4 is connected to the first sub-header 43 .
- the first sub-header 43 distributes refrigerant flowing from the refrigerant pipe 4 to the sub-heat transfer tubes 41 arranged in the first line.
- the first sub-header 43 allows refrigerant, having joined together from the sub-heat transfer tubes 41 arranged in the first line, to flow out to the refrigerant pipe 4 .
- the second sub-header 44 is provided to be opposite to the first sub-header 43 and the third sub-header 45 .
- the other end portion of each of the sub-heat transfer tubes 41 arranged in the first line and the second line is inserted into the second sub-header 44 .
- the second sub-header 44 is connected to the second main header 34 through a second partition plate 24 .
- the second partition plate 24 partitions the internal space into the second main header 34 and the second sub-header 44 .
- the second sub-header 44 distributes refrigerant, having joined together from the sub-heat transfer tubes 41 arranged in the first line, to the sub-heat transfer tubes 41 arranged in the second line.
- the second sub-header 44 distributes refrigerant, having joined together from the sub-heat transfer tubes 41 arranged in the second line, to the sub-heat transfer tubes 41 arranged in the first line.
- the third sub-header 45 is provided parallel to the first sub-header 43 .
- One end portion of each of the sub-heat transfer tubes 41 arranged in the second line is inserted into the third sub-header 45 .
- the third sub-header 45 is connected to the third main header 35 such that their internal spaces communicate with each other.
- the third sub-header 45 allows refrigerant, flowing from the sub-heat transfer tubes 41 arranged in the second line, to flow into the third main header 35 of the main heat exchanger 21 .
- the third sub-header 45 distributes refrigerant flowing from the third main header 35 to the sub-heat transfer tubes 41 arranged in the second line.
- the first sub-header 43 and the third sub-header 45 may be integrated into one header, and the sub-heat exchanger 22 may include a partition portion (not illustrated) at the central portion of the one header to partition the internal space into sub-spaces.
- FIG. 5 is a configuration diagram illustrating the sub-heat transfer tubes 41 and the first sub-header 43 according to Embodiment 1.
- FIG. 5 illustrates the cross-section of the first sub-header 43 taken along the A-A direction illustrated in FIG. 3 .
- dimensions of the parts of the sub-heat exchanger 22 , properties of refrigerant flowing in the sub-heat transfer tubes 41 , and other specifications are explained below. Note that, in the explanations below, the term “cross-section” refers to a cross-section perpendicular to the direction in which the flow passage formed in the sub-heat transfer tube 41 extends.
- the configuration of the sub-heat exchanger 22 denoted with the suffix “2” is equivalent to the corresponding configuration of the main heat exchanger 21 denoted with the suffix “1” in place of the suffix “2.”
- the equivalent diameter [m] of the cross-section of the flow passage of each of the sub-heat transfer tubes 41 is represented as D 2 .
- the cross-sectional area of the flow passages of each of the sub-heat transfer tubes 41 is represented as Ta 2 .
- the cross-sectional area Ta 2 of the flow passages is the sum of the cross-sectional areas of the plurality of flow passages formed in the sub-heat transfer tube 41 .
- the sum total of the cross-sectional areas of the flow passages of the sub-heat transfer tubes 41 is represented as AT 2 .
- the sum total AT 2 of the cross-sectional areas of the flow passages refers to a value obtained by multiplying the cross-sectional area Ta 2 of the flow passages of a single sub-heat transfer tube 41 by the number N 2 of the sub-heat transfer tubes 41 .
- the cross-sectional area of the first sub-header 43 per each of the sub-heat transfer tubes 41 is represented as Ha 2 .
- the cross-sectional area Ha 2 of the first sub-header 43 per each of the sub-heat transfer tubes 41 refers to a value obtained by dividing the cross-sectional area of the interior space of the first sub-header 43 by the number N 2 of the sub-heat transfer tubes 41 .
- the cross-sectional area Ha 2 of the first sub-header 43 per each of the sub-heat transfer tubes 41 refers to the area of the region illustrated in FIG. 5 that is hatched laterally to the sheet plane.
- the sub-heat exchanger 22 satisfies Expression (3) below.
- the sub-heat exchanger 22 also satisfies Expression (5) below, where the flow rate [kG/h] of all refrigerant flowing through the sub-heat exchanger 22 is represented as Gr 2 , the density [kG/m 3 ] of liquid refrigerant flowing in the sub-heat transfer tubes 41 is represented as ⁇ L 2 , the density [kG/m 3 ] of gas refrigerant flowing in the sub-heat transfer tubes 41 is represented as ⁇ G 2 , and the quality [ ⁇ ] of refrigerant flowing in the sub-heat exchanger 22 is represented as X 2 .
- Expression (5) the flow rate [kG/h] of all refrigerant flowing through the sub-heat exchanger 22 is represented as Gr 2 , the density [kG/m 3 ] of liquid refrigerant flowing in the sub-heat transfer tubes 41 is represented as ⁇ L 2 , the density [kG/m 3 ] of gas refrigerant flowing in the sub-heat transfer tubes 41 is represented as ⁇
- FIG. 6 is a graph illustrating heat exchange performance of the heat exchanger 7 according to Embodiment 1.
- the vertical axis illustrated in FIG. 6 represents heat exchange performance of the heat exchanger 7 .
- the horizontal axis illustrated in FIG. 6 represents the ratio of the sub-heat exchanger 22 in the heat exchanger 7 .
- the ratio of the sub-heat exchanger 22 refers to the ratio of the number N 2 of the sub-heat transfer tubes 41 to the total number N 1 +N 2 of the main heat transfer tubes 31 and the sub-heat transfer tubes 41 .
- the heat exchanger 7 has high heat exchange efficiency when the ratio of the sub-heat exchanger 22 ranges from 10% to 40%.
- the heat exchanger 7 satisfies Expression (1) below for the number of the main heat transfer tubes 31 and the number of the sub-heat transfer tubes 41 . Because of this expression, the heat exchanger 7 achieves high heat exchange performance.
- FIG. 7 is a graph illustrating the conditions under which flooding occurs according to Embodiment 1.
- the flooding is a phenomenon in which when refrigerant in a two-phase gas-liquid state flows upward inside the heat transfer tubes, portion of the refrigerant in a liquid state in the vicinity of the gas-liquid interface flows backward in the reverse direction to the flow of another portion of the refrigerant in a gas state, so that the refrigerant in a two-phase gas-liquid state stagnates in the heat transfer tubes. If the flooding has occurred in the heat transfer tubes, pressure loss of refrigerant flowing in the heat transfer tubes will be caused. With reference to FIG.
- FIG. 7 illustrates the results of the examination of the conditions under which the flooding occurs when the velocity of refrigerant flowing in the heat transfer tubes is varied in the heat exchanger 7 that satisfies Expressions (1) to (3).
- the vertical axis illustrated in FIG. 7 represents the dimensionless quantity jG* (1/2) derived from Expression (6) below, where the flow rate [m/s] of gas refrigerant flowing in the heat transfer tubes is represented as jG.
- the horizontal axis illustrated in FIG. 7 represents the dimensionless quantity jL* (1/2) derived from Expression (7) below, where the flow rate [m/s] of liquid refrigerant flowing in the heat transfer tubes is represented as jL.
- the up-pointing triangle marks and the plus signs illustrated in FIG. 7 represent the values of jG* (1/2) and the values of jL* (1/2) when the flooding has occurred.
- the square marks and the down-pointing triangle marks illustrated in FIG. 7 represent the values of jG* (1/2) and the values of jL* (1/2) when the flooding has ended. That is, FIG. 7 shows that the flooding occurs within the range of 0.88 ⁇ C ⁇ 1. It is also known that, in a case of C ⁇ 0.88, liquid refrigerant flows downward throughout the heat transfer tubes to the bottom.
- Expression (18) corresponds to Expressions (4) and (5). That is, the main heat exchanger 21 and the sub-heat exchanger 22 according to Embodiment 1 meet the configuration with C>1 derived from the experiment illustrated in FIG. 7 . Because of this configuration, the main heat exchanger 21 and the sub-heat exchanger 22 according to Embodiment 1 reduce the likelihood of stagnation and back flow of refrigerant when the refrigerant flows upward in the main heat transfer tubes 31 and the sub-heat transfer tubes 41 .
- the relationship between the number of the main heat transfer tubes 31 and the number of the sub-heat transfer tubes 41 satisfies Expression (1) below.
- the main heat exchanger 21 satisfies Expressions (2) and (4) below
- the sub-heat exchanger 22 satisfies Expressions (3) and (5) below.
- the likelihood of stagnation and back flow of refrigerant is thus reduced when the refrigerant flows upward in the heat transfer tubes. Therefore, the heat exchanger has improved heat exchange performance without causing pressure loss of refrigerant in the heat transfer tubes.
- the flow rate of refrigerant does not decrease. This allows the heat exchanger 7 to have improved condensation performance of the sub-heat exchanger 22 even when the heat exchanger 7 operates as a condenser and the sub-heat exchanger 22 operates as a subcooling device.
- 1 air-conditioning apparatus
- 2 outdoor unit
- 3 indoor unit
- 4 refrigerant pipe
- 5 compressor
- 6 flow switching device
- 7 heat exchanger
- 8 outdoor fan
- 9 expansion unit
- 11 indoor heat exchanger
- 12 indoor fan
- 21 main heat exchanger
- 22 sub-heat exchanger
- 23 first partition plate
- 24 second partition plate
- 31 main heat transfer tube
- 32 main fin
- 33 first main header
- 34 second main header
- 35 third main header
- 41 sub-heat transfer tube
- 42 sub-fin
- 43 first sub-header
- 44 second sub-header
- 45 third sub-header
Abstract
A heat exchanger satisfies Expression (1) below, where the number of the main heat transfer tubes is represented as N1, and the number of the sub-heat transfer tubes is represented as N2. In this heat exchanger, the main heat exchanger satisfies Expressions (2) and (3) below, while the sub-heat exchanger satisfies Expressions (4) and (5) below.0.1<N2(N1+N2)<0.4 (1)0.03<Ta1/Ha1<0.3 (2)0.03<Ta2/Ha2<0.3 (3)AT1<Gr1/(G×D1(ρL1−ρG1))(1/2)×(X1(1/2)×ρG1(−1/4)+(1−X1)(1/2)×ρL1(−1/4))2 (4)AT2<Gr2/(G×D2(ρL2−ρG2))(1/2)×(X2(1/2)×ρG2(−1/4)+(1−X2)(1/2)×ρL2(−1/4))2 (5)
Description
- The present disclosure relates to a heat exchanger including heat transfer tubes, and also relates to an air-conditioning apparatus including the heat exchanger.
- Some heat exchangers has been known that includes a plurality of heat transfer tubes, and a pair of headers into which opposite end portions of the heat transfer tubes are inserted.
Patent Literature 1 discloses a heat exchanger in which a value of the ratio, obtained by dividing the cross-sectional area of flow passages of a single heat transfer tube by the cross-sectional area of the header per the single heat transfer tube, ranges from 3% to 30%.Patent Literature 1 applies this ratio to the heat exchanger to improve its heat exchange performance. -
- Patent Literature 1: Japanese Patent No. 4686062
- However, as disclosed in
Patent Literature 1, in the heat exchanger with a relatively large number of heat transfer tubes, when a low air conditioning load is applied to the heat exchanger, and thus a refrigerant flow rate is relatively low, then refrigerant in a two-phase gas-liquid state may not be able to flow upward inside the heat transfer tubes, but may flow backward. InPatent Literature 1, there is a possibility that this back flow may cause pressure loss inside the heat transfer tubes, and consequently heat exchange performance may be degraded. - The present disclosure has been achieved to solve the above problems, and it is an object of the present disclosure to provide a heat exchanger and an air-conditioning apparatus including the heat exchanger, in which the heat exchanger reduces the likelihood of the occurrence of pressure loss of refrigerant in heat transfer tubes to improve heat exchange performance.
- A heat exchanger according to an embodiment of the present disclosure includes a main heat exchanger and a sub-heat exchanger connected to the main heat exchanger. The main heat exchanger includes a plurality of main heat transfer tubes extending in an up-down direction, each of the plurality of main heat transfer tubes having a flow passage inside which refrigerant flows, a first main header into which one end portion of each of the plurality of main heat transfer tubes is inserted, main fins provided to the plurality of main heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of main heat transfer tubes, and a second main header into which an other end portion of each of the plurality of main heat transfer tubes is inserted, the second main header being opposite to the first main header. The sub-heat exchanger includes a plurality of sub-heat transfer tubes extending in an up-down direction, each of the plurality of sub-heat transfer tubes having a flow passage inside which refrigerant flows, sub-fins provided to the plurality of sub-heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of sub-heat transfer tubes, a first sub-header into which one end portion of each of the plurality of sub-heat transfer tubes is inserted, and a second sub-header into which an other end portion of each of the plurality of sub-heat transfer tubes is inserted, the second sub-header being opposite to the first sub-header. The heat exchanger satisfies Expression (1) below, where the number of the plurality of main heat transfer tubes is represented as N1, and the number of the plurality of sub-heat transfer tubes is represented as N2. The heat exchanger satisfies Expressions (2) and (3) below, where a cross-sectional area of the flow passage of each of the plurality of main heat transfer tubes is represented as Ta1, a cross-sectional area of the flow passage of each of the plurality of sub-heat transfer tubes is represented as Ta2, a cross-sectional area of the first main header per each of the plurality of main heat transfer tubes is represented as Ha1, and a cross-sectional area of the first sub-header per each of the plurality of sub-heat transfer tubes is represented as Ha2. The heat exchanger satisfies Expressions (4) and (5) below, where a sum total of cross-sectional areas of the flow passages of the plurality of main heat transfer tubes is represented as AT1, a sum total of cross-sectional areas of the flow passages of the plurality of sub-heat transfer tubes is represented as AT2, a flow rate [kG/h] of all refrigerant flowing through the main heat exchanger is represented as Gr1, a flow rate [kG/h] of all refrigerant flowing through the sub-heat exchanger is represented as Gr2, a gravitational acceleration [m/s2] is represented as G, an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of main heat transfer tubes is represented as D1, an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of sub-heat transfer tubes is represented as D2, a density [kG/m3] of liquid refrigerant flowing in the plurality of main heat transfer tubes is represented as ρL1, a density [kG/m3] of liquid refrigerant flowing in the plurality of sub-heat transfer tubes is represented as ρL2, a density [kG/m3] of gas refrigerant flowing in the plurality of main heat transfer tubes is represented as ρG1, a density [kG/m3] of gas refrigerant flowing in the plurality of sub-heat transfer tubes is represented as ρG2, a quality [−] of refrigerant flowing in the main heat exchanger is represented as X1, and a quality [−] of refrigerant flowing in the sub-heat exchanger is represented as X2.
-
0.1<N 2(N 1 +N 2)<0.4 (1) -
0.03<Ta 1 /Ha 1<0.3 (2) -
0.03<Ta 2 /Ha 2<0.3 (3) -
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4) -
AT 2 <Gr 2/(G×D 2(ρL 2 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5) - In the heat exchanger according to an embodiment of the present disclosure, the relationship between the number of the main heat transfer tubes and the number of the sub-heat transfer tubes satisfies Expression (1) below. In this heat exchanger, the main heat exchanger satisfies Expressions (2) and (4) below, while the sub-heat exchanger satisfies Expressions (3) and (5) below. The likelihood of stagnation and back flow of refrigerant is thus reduced when the refrigerant flows upward in the heat transfer tubes. Therefore, the heat exchanger has improved heat exchange performance without causing pressure loss of refrigerant in the heat transfer tubes.
-
0.1<N 2(N 1 +N 2)<0.4 (1) -
0.03<Ta 1 /Ha 1<0.3 (2) -
0.03<Ta 2 /Ha 2<0.3 (3) -
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4) -
AT 2 <Gr 2/(G×D 2(ρL 2 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5) -
FIG. 1 is a circuit diagram illustrating an air-conditioning apparatus 1 according toEmbodiment 1. -
FIG. 2 is a perspective view illustrating aheat exchanger 7 according toEmbodiment 1. -
FIG. 3 is a plan view illustrating theheat exchanger 7 according to Embodiment 1. -
FIG. 4 is a configuration diagram illustrating mainheat transfer tubes 31 and a firstmain header 33 according toEmbodiment 1. -
FIG. 5 is a configuration diagram illustratingsub-heat transfer tubes 41 and afirst sub-header 43 according toEmbodiment 1. -
FIG. 6 is a graph illustrating heat exchange performance of theheat exchanger 7 according to Embodiment 1. -
FIG. 7 is a graph illustrating the conditions under which flooding occurs according toEmbodiment 1. - An air-
conditioning apparatus 1 according toEmbodiment 1 is described hereinafter with reference to the drawings.FIG. 1 is a circuit diagram illustrating the air-conditioning apparatus 1 according toEmbodiment 1. As illustrated inFIG. 1 , the air-conditioning apparatus 1 includes an outdoor unit 2, anindoor unit 3, and a refrigerant pipe 4. Note thatFIG. 1 illustrates an example in which oneindoor unit 3 is provided, however, two or moreindoor units 3 may be provided. - The outdoor unit 2 includes a compressor 5, a flow switching device 6, a
heat exchanger 7, an outdoor fan 8, and an expansion unit 9. Theindoor unit 3 includes anindoor heat exchanger 11 and anindoor fan 12. The refrigerant pipe 4 connects the compressor 5, the flow switching device 6, theheat exchanger 7, the expansion unit 9, and theindoor heat exchanger 11 to form a refrigerant circuit in which refrigerant flows. - The compressor 5 is configured to suck refrigerant in a low-temperature and low-pressure state, compress the sucked refrigerant into a high-temperature and high-pressure state, and discharge the compressed refrigerant. The flow switching device 6 is configured to change the flow directions of refrigerant in the refrigerant circuit. For example, the flow switching device 6 is a four-way valve. The
heat exchanger 7 is configured to exchange heat between refrigerant and outdoor air. Theheat exchanger 7 operates as a condenser during cooling operation, and operates as an evaporator during heating operation. The outdoor fan 8 is a device to deliver outdoor air to theheat exchanger 7. The expansion unit 9 is a pressure reducing valve or an expansion valve to reduce the pressure of refrigerant and expand the refrigerant. - The
indoor heat exchanger 11 is configured to exchange heat between room air and refrigerant. Theindoor heat exchanger 11 operates as an evaporator during cooling operation, and operates as a condenser during heating operation. Theindoor fan 12 is a device to deliver room air to theindoor heat exchanger 11. - Operation of the air-
conditioning apparatus 1 is described below. First, cooling operation is described. During cooling operation, refrigerant sucked into the compressor 5 is compressed by the compressor 5 into a high-temperature and high-pressure gas state and then discharged. The gas refrigerant in a high-temperature and high-pressure state discharged from the compressor 5 passes through the flow switching device 6 and flows into theheat exchanger 7, which operates as a condenser. Refrigerant flowing into theheat exchanger 7 exchanges heat with outdoor air delivered by the outdoor fan 8, and condenses into liquid. The refrigerant in a liquid state flows into the expansion unit 9, and is reduced in pressure and expanded, so that the refrigerant is brought into a low-temperature and low-pressure two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state flows into theindoor heat exchanger 11, which operates as an evaporator. Refrigerant flowing into theindoor heat exchanger 11 exchanges heat with room air delivered by theindoor fan 12, and evaporates into gas. At this time, the room air is cooled and thus cooling is performed in the room. Thereafter, the gas refrigerant having evaporated into a low-temperature and low-pressure state passes through the flow switching device 6 and is sucked into the compressor 5. - Next, heating operation is described. During heating operation, refrigerant sucked into the compressor 5 is compressed by the compressor 5 into a high-temperature and high-pressure gas state and then discharged. The high-temperature and high-pressure gas refrigerant discharged from the compressor 5 passes through the flow switching device 6 and flows into the
indoor heat exchanger 11, which operates as a condenser. Refrigerant flowing into theindoor heat exchanger 11 exchanges heat with room air delivered by theindoor fan 12, and condenses into liquid. At this time, the indoor air is heated and thus heating is performed in the room. The refrigerant in a liquid state flows into the expansion unit 9, and is reduced in pressure and expanded, so that the refrigerant is brought into a low-temperature and low-pressure two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state flows into theheat exchanger 7, which operates as an evaporator. Refrigerant flowing into theheat exchanger 7 exchanges heat with outdoor air delivered by the outdoor fan 8, and evaporates into gas. Thereafter, the gas refrigerant having evaporated into a low-temperature and low-pressure state passes through the flow switching device 6 and is sucked into the compressor 5. -
FIG. 2 is a perspective view illustrating theheat exchanger 7 according toEmbodiment 1.FIG. 3 is a plan view illustrating theheat exchanger 7 according toEmbodiment 1. The open arrows illustrated inFIG. 2 represent the flow of refrigerant when theheat exchanger 7 operates as an evaporator. The hatched arrow represents the flow of air passing through theheat exchanger 7. The configuration of theheat exchanger 7 is described below in detail. Note that the configuration equivalent to that of theheat exchanger 7 may be applied to theindoor heat exchanger 11. As illustrated inFIG. 2 , theheat exchanger 7 includes amain heat exchanger 21 and asub-heat exchanger 22. When theheat exchanger 7 operates as a condenser, themain heat exchanger 21 is located upstream of thesub-heat exchanger 22. When theheat exchanger 7 operates as a condenser, thesub-heat exchanger 22 operates as a subcooling device. Note that theheat exchanger 7 may be formed into an L-shape in top view such that theheat exchanger 7 extends along the back face and the side face of the housing of the outdoor unit 2. In this case, a portion of theheat exchanger 7 located beside the back face of the housing, and another portion of theheat exchanger 7 located beside the side face of the housing may be connected through a connection pipe, or may be formed integrally with each other. - As illustrated in
FIG. 2 , themain heat exchanger 21 includes mainheat transfer tubes 31,main fins 32, a firstmain header 33, a secondmain header 34, and a thirdmain header 35. Each of the mainheat transfer tubes 31 has a plurality of flow passages inside which refrigerant flows. For example, the mainheat transfer tubes 31 are flat tubes. The mainheat transfer tubes 31 extend in the up-down direction. The number of the mainheat transfer tubes 31 provided in themain heat exchanger 21 is N1. In thepresent Embodiment 1, the mainheat transfer tubes 31 are arranged in two parallel lines, which are a first line and a second line. Note that the mainheat transfer tubes 31 may be arranged only in a single line. Each of themain fins 32 is, for example, a corrugated fin, and themain fins 32 are provided to the mainheat transfer tubes 31 and help heat exchange between air and refrigerant flowing inside the mainheat transfer tubes 31. - One end portion of each of the main
heat transfer tubes 31 arranged in the first line is inserted into the firstmain header 33. The refrigerant pipe 4 is connected to the firstmain header 33. When theheat exchanger 7 operates as a condenser, the firstmain header 33 distributes refrigerant flowing from the refrigerant pipe 4 to the mainheat transfer tubes 31 arranged in the first line. When theheat exchanger 7 operates as an evaporator, the firstmain header 33 allows refrigerant, having joined together from the mainheat transfer tubes 31 arranged in the first line, to flow out to the refrigerant pipe 4. - The second
main header 34 is provided to be opposite to the firstmain header 33 and the thirdmain header 35. The other end portion of each of the mainheat transfer tubes 31 arranged in the first line and the second line is inserted into the secondmain header 34. When theheat exchanger 7 operates as a condenser, the secondmain header 34 distributes refrigerant, having joined together from the mainheat transfer tubes 31 arranged in the first line, to the mainheat transfer tubes 31 arranged in the second line. When theheat exchanger 7 operates as an evaporator, the secondmain header 34 distributes refrigerant, having joined together from the mainheat transfer tubes 31 arranged in the second line, to the mainheat transfer tubes 31 arranged in the first line. - The third
main header 35 is provided parallel to the firstmain header 33. One end portion of each of the mainheat transfer tubes 31 arranged in the second line is inserted into the thirdmain header 35. When theheat exchanger 7 operates as a condenser, the thirdmain header 35 allows refrigerant, flowing from the mainheat transfer tubes 31 arranged in the second line, to flow into thethird sub-header 45 of thesub-heat exchanger 22, which is described later. When theheat exchanger 7 operates as an evaporator, the thirdmain header 35 distributes refrigerant flowing from the third sub-header 45 to the mainheat transfer tubes 31 arranged in the second line. Note that, in themain heat exchanger 21, the firstmain header 33 and the thirdmain header 35 may be integrated into one header, and themain heat exchanger 21 may include a partition portion (not illustrated) at the central portion of the one header to partition the internal space into sub-spaces. -
FIG. 4 is a configuration diagram illustrating the mainheat transfer tubes 31 and the firstmain header 33 according toEmbodiment 1.FIG. 4 illustrates the cross-section of the firstmain header 33 taken along the A-A direction illustrated inFIG. 3 . With reference toFIG. 4 , dimensions of the parts of themain heat exchanger 21, properties of refrigerant flowing in the mainheat transfer tubes 31, and other specifications are explained below. Note that, in the explanations below, the term “cross-section” refers to a cross-section perpendicular to the direction in which the flow passage formed in the mainheat transfer tube 31 extends. As illustrated inFIG. 4 , the equivalent diameter [m] of the cross-section of the flow passage of each of the mainheat transfer tubes 31 is represented as D1. The cross-sectional area of the flow passages of each of the mainheat transfer tubes 31 is represented as Ta1. The cross-sectional area Ta1 of the flow passages is the sum of the cross-sectional areas of the plurality of flow passages formed in the mainheat transfer tube 31. - The sum total of the cross-sectional areas of the flow passages of the main
heat transfer tubes 31 is represented as AT1. The sum total AT1 of the cross-sectional areas of the flow passages refers to a value obtained by multiplying the cross-sectional area Ta1 of the flow passages of a single mainheat transfer tube 31 by the number N1 of the mainheat transfer tubes 31. The cross-sectional area of the firstmain header 33 per each of the mainheat transfer tubes 31 is represented as Ha1. The cross-sectional area Ha1 of the firstmain header 33 per each of the mainheat transfer tubes 31 refers to a value obtained by dividing the cross-sectional area of the interior space of the firstmain header 33 by the number N1 of the mainheat transfer tubes 31. The cross-sectional area Ha1 of the firstmain header 33 per each of the mainheat transfer tubes 31 refers to the area of the region illustrated inFIG. 4 that is hatched laterally to the sheet plane. Themain heat exchanger 21 satisfies Expression (2) below. -
[Expression 6] -
0.03<Ta 1 /Ha 1<0.3 (2) - The
main heat exchanger 21 also satisfies Expression (4) below, where the flow rate [kG/h] of all refrigerant flowing through themain heat exchanger 21 is represented as Gr1, the density [kG/m3] of liquid refrigerant flowing in the mainheat transfer tubes 31 is represented as ρL1, the density [kG/m3] of gas refrigerant flowing in the mainheat transfer tubes 31 is represented as ρG1, the quality [−] of refrigerant flowing in themain heat exchanger 21 is represented as X1, and the gravitational acceleration [m/s2] is represented as G. -
[Expression 7] -
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4) - As illustrated in
FIG. 2 , thesub-heat exchanger 22 includessub-heat transfer tubes 41, sub-fins 42, afirst sub-header 43, asecond sub-header 44, and athird sub-header 45. Each of thesub-heat transfer tubes 41 has a plurality of flow passages inside which refrigerant flows. For example, thesub-heat transfer tubes 41 are flat tubes. Thesub-heat transfer tubes 41 extend in the up-down direction. The number of thesub-heat transfer tubes 41 provided in thesub-heat exchanger 22 is N2. In thepresent Embodiment 1, thesub-heat transfer tubes 41 are arranged in two parallel lines, which are a first line and a second line. Note that thesub-heat transfer tubes 41 may be arranged only in a single line. Each of the sub-fins 42 is, for example, a corrugated fin, and the sub-fins 42 are provided to thesub-heat transfer tubes 41 and help heat exchange between air and refrigerant flowing inside thesub-heat transfer tubes 41. - One end portion of each of the
sub-heat transfer tubes 41 arranged in the first line is inserted into thefirst sub-header 43. Thefirst sub-header 43 is connected to the firstmain header 33 through afirst partition plate 23. Thefirst partition plate 23 partitions the internal space into the firstmain header 33 and thefirst sub-header 43. The refrigerant pipe 4 is connected to thefirst sub-header 43. When theheat exchanger 7 operates as an evaporator, thefirst sub-header 43 distributes refrigerant flowing from the refrigerant pipe 4 to thesub-heat transfer tubes 41 arranged in the first line. When theheat exchanger 7 operates as a condenser, thefirst sub-header 43 allows refrigerant, having joined together from thesub-heat transfer tubes 41 arranged in the first line, to flow out to the refrigerant pipe 4. - The
second sub-header 44 is provided to be opposite to thefirst sub-header 43 and thethird sub-header 45. The other end portion of each of thesub-heat transfer tubes 41 arranged in the first line and the second line is inserted into thesecond sub-header 44. Thesecond sub-header 44 is connected to the secondmain header 34 through asecond partition plate 24. Thesecond partition plate 24 partitions the internal space into the secondmain header 34 and thesecond sub-header 44. When theheat exchanger 7 operates as an evaporator, thesecond sub-header 44 distributes refrigerant, having joined together from thesub-heat transfer tubes 41 arranged in the first line, to thesub-heat transfer tubes 41 arranged in the second line. When theheat exchanger 7 operates as a condenser, thesecond sub-header 44 distributes refrigerant, having joined together from thesub-heat transfer tubes 41 arranged in the second line, to thesub-heat transfer tubes 41 arranged in the first line. - The
third sub-header 45 is provided parallel to thefirst sub-header 43. One end portion of each of thesub-heat transfer tubes 41 arranged in the second line is inserted into thethird sub-header 45. Thethird sub-header 45 is connected to the thirdmain header 35 such that their internal spaces communicate with each other. When theheat exchanger 7 operates as an evaporator, thethird sub-header 45 allows refrigerant, flowing from thesub-heat transfer tubes 41 arranged in the second line, to flow into the thirdmain header 35 of themain heat exchanger 21. When theheat exchanger 7 operates as a condenser, thethird sub-header 45 distributes refrigerant flowing from the thirdmain header 35 to thesub-heat transfer tubes 41 arranged in the second line. Note that, in thesub-heat exchanger 22, thefirst sub-header 43 and the third sub-header 45 may be integrated into one header, and thesub-heat exchanger 22 may include a partition portion (not illustrated) at the central portion of the one header to partition the internal space into sub-spaces. -
FIG. 5 is a configuration diagram illustrating thesub-heat transfer tubes 41 and thefirst sub-header 43 according toEmbodiment 1.FIG. 5 illustrates the cross-section of thefirst sub-header 43 taken along the A-A direction illustrated inFIG. 3 . With reference toFIG. 5 , dimensions of the parts of thesub-heat exchanger 22, properties of refrigerant flowing in thesub-heat transfer tubes 41, and other specifications are explained below. Note that, in the explanations below, the term “cross-section” refers to a cross-section perpendicular to the direction in which the flow passage formed in thesub-heat transfer tube 41 extends. In the explanations below, the configuration of thesub-heat exchanger 22 denoted with the suffix “2” is equivalent to the corresponding configuration of themain heat exchanger 21 denoted with the suffix “1” in place of the suffix “2.” The equivalent diameter [m] of the cross-section of the flow passage of each of thesub-heat transfer tubes 41 is represented as D2. The cross-sectional area of the flow passages of each of thesub-heat transfer tubes 41 is represented as Ta2. The cross-sectional area Ta2 of the flow passages is the sum of the cross-sectional areas of the plurality of flow passages formed in thesub-heat transfer tube 41. - The sum total of the cross-sectional areas of the flow passages of the
sub-heat transfer tubes 41 is represented as AT2. The sum total AT2 of the cross-sectional areas of the flow passages refers to a value obtained by multiplying the cross-sectional area Ta2 of the flow passages of a singlesub-heat transfer tube 41 by the number N2 of thesub-heat transfer tubes 41. The cross-sectional area of the first sub-header 43 per each of thesub-heat transfer tubes 41 is represented as Ha2. The cross-sectional area Ha2 of the first sub-header 43 per each of thesub-heat transfer tubes 41 refers to a value obtained by dividing the cross-sectional area of the interior space of thefirst sub-header 43 by the number N2 of thesub-heat transfer tubes 41. The cross-sectional area Ha2 of the first sub-header 43 per each of thesub-heat transfer tubes 41 refers to the area of the region illustrated inFIG. 5 that is hatched laterally to the sheet plane. Thesub-heat exchanger 22 satisfies Expression (3) below. -
[Expression 8] -
0.03<Ta 2 /Ha 2<0.3 (3) - The
sub-heat exchanger 22 also satisfies Expression (5) below, where the flow rate [kG/h] of all refrigerant flowing through thesub-heat exchanger 22 is represented as Gr2, the density [kG/m3] of liquid refrigerant flowing in thesub-heat transfer tubes 41 is represented as ρL2, the density [kG/m3] of gas refrigerant flowing in thesub-heat transfer tubes 41 is represented as ρG2, and the quality [−] of refrigerant flowing in thesub-heat exchanger 22 is represented as X2. -
[Expression 9] -
AT 2 <Gr 2/(G×D 1(ρL 1 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5) -
FIG. 6 is a graph illustrating heat exchange performance of theheat exchanger 7 according toEmbodiment 1. The vertical axis illustrated inFIG. 6 represents heat exchange performance of theheat exchanger 7. The horizontal axis illustrated inFIG. 6 represents the ratio of thesub-heat exchanger 22 in theheat exchanger 7. The ratio of thesub-heat exchanger 22 refers to the ratio of the number N2 of thesub-heat transfer tubes 41 to the total number N1+N2 of the mainheat transfer tubes 31 and thesub-heat transfer tubes 41. As illustrated inFIG. 6 , theheat exchanger 7 has high heat exchange efficiency when the ratio of thesub-heat exchanger 22 ranges from 10% to 40%. Theheat exchanger 7 satisfies Expression (1) below for the number of the mainheat transfer tubes 31 and the number of thesub-heat transfer tubes 41. Because of this expression, theheat exchanger 7 achieves high heat exchange performance. -
[Expression 10] -
0.1<N 2(N 1 +N 2)<0.4 (1) -
FIG. 7 is a graph illustrating the conditions under which flooding occurs according toEmbodiment 1. The flooding is a phenomenon in which when refrigerant in a two-phase gas-liquid state flows upward inside the heat transfer tubes, portion of the refrigerant in a liquid state in the vicinity of the gas-liquid interface flows backward in the reverse direction to the flow of another portion of the refrigerant in a gas state, so that the refrigerant in a two-phase gas-liquid state stagnates in the heat transfer tubes. If the flooding has occurred in the heat transfer tubes, pressure loss of refrigerant flowing in the heat transfer tubes will be caused. With reference toFIG. 7 , an explanation is given for the fact that the likelihood of stagnation and back flow of refrigerant is reduced when the refrigerant flows upward in the mainheat transfer tubes 31 and thesub-heat transfer tubes 41 according toEmbodiment 1. Note that, in the explanations below, the suffixes “1” and “2” are appropriately omitted. The description in which the suffixes “1” and “2” are omitted explains each of themain heat exchanger 21 and thesub-heat exchanger 22. -
FIG. 7 illustrates the results of the examination of the conditions under which the flooding occurs when the velocity of refrigerant flowing in the heat transfer tubes is varied in theheat exchanger 7 that satisfies Expressions (1) to (3). The vertical axis illustrated inFIG. 7 represents the dimensionless quantity jG*(1/2) derived from Expression (6) below, where the flow rate [m/s] of gas refrigerant flowing in the heat transfer tubes is represented as jG. The horizontal axis illustrated inFIG. 7 represents the dimensionless quantity jL*(1/2) derived from Expression (7) below, where the flow rate [m/s] of liquid refrigerant flowing in the heat transfer tubes is represented as jL. The point of intersection of the vertical line and the horizontal line represents the dimensionless quantity C=jG*(1/2)+jL*(1/2). -
[Expression 11] -
jG*=jG×(ρG/(G×D×(ρL−ρG)))(1/2) (6) -
[Expression 12] -
jL*=jL×(ρL/(G×D×(ρL−ρG)))(1/2) (7) - The up-pointing triangle marks and the plus signs illustrated in
FIG. 7 represent the values of jG*(1/2) and the values of jL*(1/2) when the flooding has occurred. In addition, the square marks and the down-pointing triangle marks illustrated inFIG. 7 represent the values of jG*(1/2) and the values of jL*(1/2) when the flooding has ended. That is,FIG. 7 shows that the flooding occurs within the range of 0.88<C≤1. It is also known that, in a case of C≤0.88, liquid refrigerant flows downward throughout the heat transfer tubes to the bottom. Therefore, where theheat exchanger 7 satisfies C>1, that is, Expression (8) below, when refrigerant flows upward in the mainheat transfer tubes 31 and thesub-heat transfer tubes 41, the likelihood of stagnation and back flow of the refrigerant is reduced. -
[Expression 13] -
jG* (1/2) +jL* (1/2)>1 (8) - Where the flow rate [kg/h] of liquid refrigerant flowing in the heat transfer tubes is represented as GL, and the flow rate [kg/h] of gas refrigerant flowing in the heat transfer tubes is represented as GG, Expressions (9) to (13) below are satisfied.
-
[Expression 14] -
GG=G×X (9) -
[Expression15] -
GL=G×(1−X) (10) -
[Expression 16] -
G=Gr/AT (11) -
[Expression 17] -
jG=GG/ρG (12) -
[Expression 18] -
jL=GL/ρL (13) - On the basis of Expressions (9) and (11), Expression (14) below is satisfied. On the basis of Expressions (10) and (11), Expression (15) below is satisfied.
-
[Expression 19] -
GG=(Gr×X)/AT (14) -
[Expression 20] -
GL=(Gr×(1−X))/AT (15) - On the basis of Expressions (12) and (14), Expression (16) below is satisfied. On the basis of Expressions (13) and (15), Expression (17) below is satisfied.
-
[Expression 21] -
jG=(Gr×X)/(AT×ρG) (16) -
[Expression 22] -
jL=(Gr×(1−X))/(AT×ρL) (17) - On the basis of Expressions (6) to (8), (16), and (17), Expression (18) below is satisfied. Expression (18) corresponds to Expressions (4) and (5). That is, the
main heat exchanger 21 and thesub-heat exchanger 22 according toEmbodiment 1 meet the configuration with C>1 derived from the experiment illustrated inFIG. 7 . Because of this configuration, themain heat exchanger 21 and thesub-heat exchanger 22 according toEmbodiment 1 reduce the likelihood of stagnation and back flow of refrigerant when the refrigerant flows upward in the mainheat transfer tubes 31 and thesub-heat transfer tubes 41. -
[Expression23] -
AT<Gr/(G×D(ρL−ρG))(1/2)×(X (1/2) ×ρG (−1/4)+(1−X)(1/2) ×ρL (−1/4))2 (18) - In the heat exchanger according to the present disclosure, the relationship between the number of the main
heat transfer tubes 31 and the number of thesub-heat transfer tubes 41 satisfies Expression (1) below. In this heat exchanger, themain heat exchanger 21 satisfies Expressions (2) and (4) below, while thesub-heat exchanger 22 satisfies Expressions (3) and (5) below. The likelihood of stagnation and back flow of refrigerant is thus reduced when the refrigerant flows upward in the heat transfer tubes. Therefore, the heat exchanger has improved heat exchange performance without causing pressure loss of refrigerant in the heat transfer tubes. -
0.1<N 2(N 1 +N 2)<0.4 (1) -
0.03<Ta 1 /Ha 1<0.3 (2) -
0.03<Ta 2 /Ha 2<0.3 (3) -
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4) -
AT 2 <Gr 2/(G×D 2(ρL 2 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5) - Since no flooding occurs in the
main heat exchanger 21 and thesub-heat exchanger 22, the flow rate of refrigerant does not decrease. This allows theheat exchanger 7 to have improved condensation performance of thesub-heat exchanger 22 even when theheat exchanger 7 operates as a condenser and thesub-heat exchanger 22 operates as a subcooling device. - 1: air-conditioning apparatus, 2: outdoor unit, 3: indoor unit, 4: refrigerant pipe, 5: compressor, 6: flow switching device, 7: heat exchanger, 8: outdoor fan, 9: expansion unit, 11: indoor heat exchanger, 12: indoor fan, 21: main heat exchanger, 22: sub-heat exchanger, 23: first partition plate, 24: second partition plate, 31: main heat transfer tube, 32: main fin, 33: first main header, 34: second main header, 35: third main header, 41: sub-heat transfer tube, 42: sub-fin, 43: first sub-header, 44: second sub-header, 45: third sub-header
Claims (2)
1. A heat exchanger comprising:
a main heat exchanger; and
a sub-heat exchanger connected to the main heat exchanger,
the main heat exchanger including
a plurality of main heat transfer tubes extending in an up-down direction, each of the plurality of main heat transfer tubes having a flow passage inside which refrigerant flows,
a first main header into which one end portion of each of the plurality of main heat transfer tubes is inserted,
main fins provided to the plurality of main heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of main heat transfer tubes, and
a second main header into which an other end portion of each of the plurality of main heat transfer tubes is inserted, the second main header being opposite to the first main header,
the sub-heat exchanger including
a plurality of sub-heat transfer tubes extending in an up-down direction, each of the plurality of sub-heat transfer tubes having a flow passage inside which refrigerant flows,
sub-fins provided to the plurality of sub-heat transfer tubes and helping heat exchange between air and refrigerant flowing inside the plurality of sub-heat transfer tubes,
a first sub-header into which one end portion of each of the plurality of sub-heat transfer tubes is inserted, and
a second sub-header into which an other end portion of each of the plurality of sub-heat transfer tubes is inserted, the second sub-header being opposite to the first sub-header,
the heat exchanger satisfying Expression (1) below, where
the number of the plurality of main heat transfer tubes is represented as N1, and
the number of the plurality of sub-heat transfer tubes is represented as N2,
the heat exchanger satisfying Expressions (2) and (3) below, where
a cross-sectional area of the flow passage of each of the plurality of main heat transfer tubes is represented as Ta1,
a cross-sectional area of the flow passage of each of the plurality of sub-heat transfer tubes is represented as Ta2,
a cross-sectional area of the first main header per each of the plurality of main heat transfer tubes is represented as Ha1, and
a cross-sectional area of the first sub-header per each of the plurality of sub-heat transfer tubes is represented as Has,
the heat exchanger satisfying Expressions (4) and (5) below, where
a sum total of cross-sectional areas of the flow passages of the plurality of main heat transfer tubes is represented as AT2,
a sum total of cross-sectional areas of the flow passages of the plurality of sub-heat transfer tubes is represented as AT2,
a flow rate [kG/h] of all refrigerant flowing through the main heat exchanger is represented as Gr1,
a flow rate [kG/h] of all refrigerant flowing through the sub-heat exchanger is represented as Gr2,
a gravitational acceleration [m/s2] is represented as G,
an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of main heat transfer tubes is represented as D1,
an equivalent diameter [m] of a cross-section of the flow passage of each of the plurality of sub-heat transfer tubes is represented as D2,
a density [kG/m3] of liquid refrigerant flowing in the plurality of main heat transfer tubes is represented as ρL1,
a density [kG/m3] of liquid refrigerant flowing in the plurality of sub-heat transfer tubes is represented as ρL2,
a density [kG/m3] of gas refrigerant flowing in the plurality of main heat transfer tubes is represented as ρG1,
a density [kG/m3] of gas refrigerant flowing in the plurality of sub-heat transfer tubes is represented as ρG2,
a quality [−] of refrigerant flowing in the main heat exchanger is represented as X1, and
a quality [−] of refrigerant flowing in the sub-heat exchanger is represented as X2.
[Expression 1]
0.1<N 2(N 1 +N 2)<0.4 (1)
[Expression 2]
0.03<Ta 1 /Ha 1<0.3 (2)
[Expression 3]
0.03<Ta 2 /Ha 2<0.3 (3)
[Expression 4]
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4)
[Expression 5]
AT 2 <Gr 2/(G×D 2(ρL 2 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5)
[Expression 1]
0.1<N 2(N 1 +N 2)<0.4 (1)
[Expression 2]
0.03<Ta 1 /Ha 1<0.3 (2)
[Expression 3]
0.03<Ta 2 /Ha 2<0.3 (3)
[Expression 4]
AT 1 <Gr 1/(G×D 1(ρL 1 −ρG 1))(1/2)×(X 1 (1/2) ×ρG 1 (−1/4)+(1−X 1)(1/2) ×ρL 1 (−1/4))2 (4)
[Expression 5]
AT 2 <Gr 2/(G×D 2(ρL 2 −ρG 2))(1/2)×(X 2 (1/2) ×ρG 2 (−1/4)+(1−X 2)(1/2) ×ρL 2 (−1/4))2 (5)
2. An air-conditioning apparatus comprising:
a compressor configured to compress refrigerant;
the heat exchanger of claim 1 ;
an expansion unit configured to expand refrigerant; and
a heat exchanger configured to operate as a condenser when the heat exchanger of claim 1 operates as an evaporator, and configured to operate as an evaporator when the heat exchanger of claim 1 operates as a condenser.
Applications Claiming Priority (1)
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PCT/JP2020/020348 WO2021234955A1 (en) | 2020-05-22 | 2020-05-22 | Heat exchanger and air conditioner |
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US20230147134A1 true US20230147134A1 (en) | 2023-05-11 |
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ID=78708398
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US17/910,914 Pending US20230147134A1 (en) | 2020-05-22 | 2020-05-22 | Heat exchanger and air-conditioning apparatus |
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US (1) | US20230147134A1 (en) |
EP (1) | EP4155625A4 (en) |
JP (1) | JPWO2021234955A1 (en) |
WO (1) | WO2021234955A1 (en) |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
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JP4686062B2 (en) * | 2000-06-26 | 2011-05-18 | 昭和電工株式会社 | Evaporator |
JP2013083419A (en) * | 2011-09-30 | 2013-05-09 | Daikin Industries Ltd | Heat exchanger and air conditioner |
JP6216113B2 (en) * | 2012-04-02 | 2017-10-18 | サンデンホールディングス株式会社 | Heat exchanger and heat pump system using the same |
WO2015125743A1 (en) * | 2014-02-18 | 2015-08-27 | 三菱電機株式会社 | Air-conditioning device |
JP2016035376A (en) * | 2014-08-04 | 2016-03-17 | 株式会社デンソー | Evaporator |
JP2017116152A (en) * | 2015-12-22 | 2017-06-29 | サンデンホールディングス株式会社 | Heat exchanger |
US20190234626A1 (en) * | 2016-09-12 | 2019-08-01 | Mitsubishi Electric Corporation | Header, heat exchanger, and air-conditioning apparatus |
US11506402B2 (en) * | 2018-06-11 | 2022-11-22 | Mitsubishi Electric Corporation | Outdoor unit of air-conditioning apparatus and air-conditioning apparatus |
-
2020
- 2020-05-22 US US17/910,914 patent/US20230147134A1/en active Pending
- 2020-05-22 EP EP20937009.7A patent/EP4155625A4/en not_active Withdrawn
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JPWO2021234955A1 (en) | 2021-11-25 |
EP4155625A1 (en) | 2023-03-29 |
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