EP4116642A1 - Heat exchanger and air conditioner - Google Patents
Heat exchanger and air conditioner Download PDFInfo
- Publication number
- EP4116642A1 EP4116642A1 EP20923061.4A EP20923061A EP4116642A1 EP 4116642 A1 EP4116642 A1 EP 4116642A1 EP 20923061 A EP20923061 A EP 20923061A EP 4116642 A1 EP4116642 A1 EP 4116642A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- heat exchanger
- heat transfer
- refrigerant
- heat
- pipe
- 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 120
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 230000002542 deteriorative effect Effects 0.000 abstract description 5
- 238000001704 evaporation Methods 0.000 description 15
- 230000008020 evaporation Effects 0.000 description 15
- 239000007788 liquid Substances 0.000 description 14
- 238000000034 method Methods 0.000 description 9
- 238000005057 refrigeration Methods 0.000 description 9
- 238000001816 cooling Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- RWRIWBAIICGTTQ-UHFFFAOYSA-N difluoromethane Chemical compound FCF RWRIWBAIICGTTQ-UHFFFAOYSA-N 0.000 description 4
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 4
- 238000009835 boiling Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000001282 iso-butane Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 239000011555 saturated liquid Substances 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- WFLOTYSKFUPZQB-OWOJBTEDSA-N (e)-1,2-difluoroethene Chemical group F\C=C\F WFLOTYSKFUPZQB-OWOJBTEDSA-N 0.000 description 1
- WFLOTYSKFUPZQB-UHFFFAOYSA-N 1,2-difluoroethene Chemical group FC=CF WFLOTYSKFUPZQB-UHFFFAOYSA-N 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- NHGVZTMBVDFPHJ-UHFFFAOYSA-N formyl fluoride Chemical compound FC=O NHGVZTMBVDFPHJ-UHFFFAOYSA-N 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
- F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
- F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
- F28D1/047—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag
- F28D1/0477—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag the conduits being bent in a serpentine or zig-zag
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B39/00—Evaporators; Condensers
- F25B39/02—Evaporators
-
- 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
-
- 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
- F28F1/006—Tubular elements; Assemblies of tubular elements with variable shape, e.g. with modified tube ends, with different geometrical features
-
- 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
- F28F1/06—Tubular elements of cross-section which is non-circular crimped or corrugated in cross-section
-
- 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
- F28F1/40—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only inside the tubular element
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/02—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by influencing fluid boundary
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
- F28F13/185—Heat-exchange surfaces provided with microstructures or with porous coatings
- F28F13/187—Heat-exchange surfaces provided with microstructures or with porous coatings especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites
-
- 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
- F28D2021/0068—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for refrigerant cycles
-
- 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
- F28F1/24—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 transversely
- F28F1/32—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 transversely 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
- F28F2210/00—Heat exchange conduits
- F28F2210/08—Assemblies of conduits having different features
Definitions
- the present invention relates to a heat exchanger for an air conditioner.
- chlorofluorocarbons used as refrigerants for many refrigerators and air conditioners have a global warming effect, and various regulations have been enacted globally in order to reduce emissions of chlorofluorocarbons.
- the 2016 Kigali Amendment to the Montreal Protocol requires that industrialized countries including Japan reduce the total GWP value, which is determined by multiplying the GWP (Global Warming Potential) by the refrigerant usage, to 15% by 2036, compared to that in 2011 to 2013.
- the refrigerant mixture of the HFC refrigerant and the HFO refrigerant is superior in terms of refrigeration capacity, theoretical COP, flammability, and toxicity, for example, and may be applicable to a wide variety of refrigerators and air conditioners. It is known that a mixture of multiple refrigerants having different boiling points, which is so-called zeotropic refrigerant mixture, exhibits properties different from those of pure refrigerants and azeotropic refrigerant mixtures.
- a lower-boiling-point component is evaporated first, and subsequently a higher-boiling-point component is evaporated, and therefore, the concentration of the higher-boiling-point component is higher in a liquid phase in the vicinity of the gas-liquid interface, which suppresses further boiling of the lower-boiling-point component.
- the zeotropic refrigerant mixture it is necessary to recover from such degradation in evaporation heat transfer.
- a method for improving the heat exchange performance of an evaporator places an auxiliary heat exchanger at a refrigerant entrance side of a heat exchanger used as the evaporator, reduces the number of refrigerant flow paths of the auxiliary heat exchanger, and increases the pipe diameter thereof (PTL 1, for example).
- the auxiliary heat exchanger with the increased pipe diameter is located at a refrigerant exit side of the heat exchanger when used as a condenser.
- the refrigerant exit side of the condenser subcooled liquid flows, resulting in increase of the amount of refrigerant necessary for this refrigeration cycle due to the increased pipe diameter, and accordingly resulting in increase of the refrigerant usage.
- the present invention has been made to solve the problems as described above, and thereby obtain a heat exchanger for an air conditioner for which a zeotropic refrigerant mixture is used, and this heat exchanger, when used as an evaporator, enables reduction of the amount of required refrigerant without deteriorating the heat transfer performance.
- a heat exchanger includes:
- the amount of required refrigerant can be reduced, without deteriorating the heat exchange performance. Moreover, the manufacture cost can also be reduced.
- Fig. 1 is a refrigerant circuit diagram showing an example of an air conditioner including a heat exchanger according to Embodiment 1. The direction of refrigerant flow is indicated by solid and broken lines.
- an air conditioner 100 includes an outdoor unit 1 and an indoor unit 2 that are connected to each other by a gas pipe 3 and a liquid pipe 4 to form a single refrigerant circuit.
- a refrigerant mixture made up of two or more types of refrigerants that are different from each other in boiling point is enclosed.
- Outdoor unit 1 is equipped with a compressor 5, an outdoor heat exchanger 6, an expansion valve 7, and a four-way valve 9, and indoor unit 2 is equipped with an indoor heat exchanger 8.
- indoor heat exchanger 8 acts as an evaporator
- refrigerant discharged from compressor 5 flows through four-way valve 9 into outdoor heat exchanger 6, is reduced in pressure by expansion valve 7, and then flows out of outdoor unit 1.
- the refrigerant flowing through liquid pipe 4 into indoor unit 2 is evaporated in indoor heat exchanger 8 and flows out of indoor unit 2.
- the refrigerant then flows through gas pipe 3, returns to outdoor unit 1, and is sucked again into compressor 5.
- indoor heat exchanger 8 acts as a condenser
- refrigerant discharged from compressor 5 flows into indoor unit 2 through gas pipe 3 following a flow path setting for four-way valve 9.
- the refrigerant condensed by indoor heat exchanger 8 flows through liquid pipe 4, returns to outdoor unit 1, and is reduced in pressure in expansion valve 7.
- the refrigerant with the reduced pressure exchanges, in outdoor heat exchanger 6, heat with outdoor air, and the refrigerant is accordingly evaporated and sucked again into compressor 5 through four-way valve 9.
- Outdoor heat exchanger 6 and indoor heat exchanger 8 are each equipped with a fan (not shown), to force outdoor air and indoor air to flow to outdoor heat exchanger 6 and indoor heat exchanger 8 and thereby increase the efficiency in exchanging heat between refrigerant and air.
- a fan for example, cross flow fan, propeller fan, turbo fan, or sirocco fan may be used.
- a single heat exchanger may be equipped with a plurality of fans, or a plurality of heat exchangers may be equipped with a single fan.
- Air conditioner 100 according to Embodiment 1 has a minimum configuration required for enabling cooling operation and heating operation, and a gas-liquid separator, a receiver, an accumulator, and/or an inner heat exchanger, for example, may appropriately be added in the refrigerant circuit.
- Fig. 2 is a front view showing an example of outdoor heat exchanger 6 according to Embodiment 1.
- Outdoor heat exchanger 6 is made up of a plurality of fins 11 stacked together at intervals of about 1.5 mm therebetween, and heat transfer pipes 31 to 38 extending through these fins 11.
- Heat transfer pipes 31 to 38 are formed in a hairpin shape and closely fit in fins 11 to allow heat transfer.
- Heat transfer pipes 31 to 38 have one end or both ends connected by a plurality of U-shaped pipes 14 to form a single refrigerant flow path having a gas-side exit/entrance 12 and a liquid-side exit/entrance 13.
- liquid-side exit/entrance 13 is an entrance of the refrigerant flow path while gas-side exit/entrance 12 is an exit of the refrigerant flow path.
- the refrigerant flow direction is the opposite direction during cooling operation, and therefore, when outdoor heat exchanger 6 acts as a condenser, liquid-side exit/entrance 13 is an exit of the refrigerant flow path while gas-side exit/entrance 12 is an entrance of the refrigerant flow path.
- Fig. 3 is a cross-sectional view of the heat transfer pipes used for the heat exchanger according to the embodiment.
- Heat transfer pipes 31 to 38 forming outdoor heat exchanger 6 shown in Fig. 2 include first heat transfer pipes 31 to 36, and the first heat transfer pipes are grooved pipes having peaks and valleys on the pipe inner surface as shown for example in Fig. 3 (a) , have one end located at gas-side exit/entrance 12, and extend through fins 11 to form a first heat exchanger portion.
- Heat transfer pipes 37, 38 are second heat transfer pipes that are smooth pipes as shown in Fig. 3 (b) , have one end located at liquid-side exit/entrance 13, and extend through fins 11 to form a second heat exchanger portion.
- Heat transfer pipes 37, 38 have an inner diameter D2 smaller than an inner diameter D1 of the grooved pipes used as heat transfer pipes 31 to 36 (D1 > D2).
- the shape of the grooves in heat transfer pipes 31 to 36 is not limited. Specifically, there is no particular limitation on the inner diameter, the number of fins in the pipes (hereinafter intra-pipe fins), the height of the intra-pipe fins, the helix angle of the intra-pipe fins, and the area extension ratio, for example.
- the type of the zeotropic refrigerant mixture (hereinafter referred to as "refrigerant" as long as it is not necessary in terms of context to distinguish between zeotropic refrigerant mixture, pure refrigerant, and azeotropic refrigerant mixture) to be enclosed in air conditioner 100 is not particularly limited.
- Fig. 4 is a characteristic plot showing an example of the intra-pipe evaporation heat transfer performance relative to the dryness fraction of refrigerant in a general grooved pipe.
- the vertical axis indicates the evaporation heat transfer coefficient of the grooved pipe, represented by a relative value with respect to the evaporation heat transfer coefficient of a smooth pipe.
- the refrigerant respective characteristics of two different refrigerants, i.e., a single refrigerant and a zeotropic refrigerant mixture, are plotted by a broken line and a solid line, respectively.
- the grooved pipe exhibits an evaporation heat transfer coefficient of three or more times higher than that of the smooth pipe, regardless of the refrigerant dryness fraction, and thus significantly contributes to improvement of the heat exchange performance.
- improvement of the evaporation heat transfer coefficient relative to the smooth pipe is not significantly large, unlike the one achieved for the single refrigerant.
- the evaporation heat transfer coefficient of the grooved pipe is substantially identical to the evaporation heat transfer coefficient of the smooth pipe, and thus fails to contribute to improvement of the heat exchange performance.
- Fig. 5 is a characteristic plot showing an example of the pressure loss relative to the dryness fraction of refrigerant in a general grooved pipe.
- the vertical axis indicates the pressure loss of the grooved pipe, represented by a relative value with respect to the pressure loss of a smooth pipe.
- the broken line represents the pressure loss for a single refrigerant, and the solid line represents the pressure loss for a zeotropic refrigerant mixture.
- the pressure loss of the grooved pipe is large relative to the pressure loss of the smooth pipe, regardless of the refrigerant dryness fraction, and particularly large in the region of a refrigerant dryness fraction of 0.3 to 0.5.
- This phenomenon is substantially the same for both the single refrigerant and the zeotropic refrigerant mixture.
- the rate of increase of the pressure loss is larger. It is seen from Figs. 4 and 5 that although use of the grooved pipe for the heat exchanger improves the heat transfer performance, the heat transfer performance is not improved and only the pressure loss is increased for a refrigerant dryness fraction of 0.4 or less.
- Fig. 6 is a Ph chart showing a refrigeration cycle operation of air conditioner 100 according to Embodiment 1.
- the vertical axis indicates the pressure
- the horizontal axis indicates the specific enthalpy
- XO is a saturation line connecting points where refrigerant is saturated liquid or saturated gas.
- State A, State B, State C, and State D are respective entrance states of a process of compression, condensation, expansion, and evaporation that form a refrigeration cycle. While the refrigeration cycle shown in Fig. 6 is not limited to cooling operation or heating operation, the refrigeration cycle operation is described first for the heating operation in the following.
- State A Low-temperature low-pressure gas refrigerant at a suction position of compressor 5 is increased in pressure by compressor 5 into high-temperature high-pressure discharged gas (State B).
- the discharged gas is condensed in indoor heat exchanger 8 acting as a condenser into high-pressure subcooled liquid (State C).
- the refrigerant is subsequently reduced in pressure by expansion valve 7 into low-pressure gas-liquid two-phase refrigerant (State D).
- X1 is a line of constant dryness fraction where the refrigerant dryness fraction is 0.2.
- the refrigerant (State D) has a dryness fraction of approximately 0.2, for a condensation temperature in a range of 40°C ⁇ 10°C and an evaporation temperature in a range of 0°C ⁇ 10°C that are general operating conditions of air conditioning.
- the refrigerant dryness fraction changes from 0.2 to approximately 1.0 under most operating conditions.
- the low-pressure gas-liquid two-phase refrigerant in State D absorbs heat from outdoor air until being superheated slightly, and returns to State A to thereby complete a single refrigeration cycle.
- the smooth pipe is lower in cost than the grooved pipe, and therefore, the manufacture cost of outdoor heat exchanger 6 can be reduced.
- refrigerator oil dissolved in the liquid refrigerant may separate from the refrigerant and stay in the vicinity of the wall of the heat transfer pipe.
- Stay of the refrigerator oil may deteriorate the reliability of compressor 5, and should therefore be avoided as much as possible.
- smooth pipes in which less friction occurs can be employed to reduce the amount of staying refrigerator oil, and thereby improve the reliability of the air conditioner.
- indoor heat exchanger 8 acts as an evaporator and outdoor heat exchanger 6 acts as a condenser.
- High-temperature high-pressure gas refrigerant in State B is discharged from compressor 5, flows into outdoor heat exchanger 6 to exchange heat with outdoor air, and is then condensed into subcooled liquid refrigerant in State C.
- SC portion which is the last stage of this condensation process, i.e., SC portion that is a region after refrigerant becomes saturated liquid, most of the amount of refrigerant necessary for this refrigeration cycle is concentrated.
- heat transfer pipes 37, 38 forming the second heat exchanger portion located at the refrigerant exit side when the outdoor heat exchanger is used as a condenser have a smaller diameter than that of the other heat transfer pipes, and therefore, the amount of refrigerant present in the SC portion is reduced. Accordingly, the amount of refrigerant enclosed in air conditioner 100 is also reduced, which can contribute to reduction of the total GWP value and can lessen the environmental load.
- the smaller diameter of heat transfer pipes 37, 38 increases the refrigerant flow rate in the second heat exchanger portion to promote convection heat transfer, and therefore, it is possible to recover from the deterioration of the heat transfer performance due to the smooth pipe, and to suppress deterioration of the heat exchange performance.
- Fig. 7 is an example of a side view of one refrigerant flow path portion extracted from the heat exchanger according to Embodiment 1. While Fig. 2 shows the heat exchanger arranged in a single line, Fig. 7 shows that heat transfer pipes 31 to 38 forming one refrigerant flow path are arranged in two lines in the direction of air flow. Of eight heat transfer pipes 31 to 38, six heat transfer pipes 31 to 36 are grooved pipes and two heat transfer pipes 37, 38 are smooth pipes thinner than the grooved pipes. Namely, 25% of the total length of the refrigerant flow path that is located relatively closer to liquid-side exit/entrance 13 is formed by the smooth pipes. In Fig.
- a first heat exchanger portion formed by heat transfer pipes 31 to 36 and a second heat exchanger portion formed by heat transfer pipes 37, 38 are constituted in the form of a single unit, which reduces the number of process steps required for manufacture to thereby enable reduction of the manufacture cost.
- heat transfer pipes leading to gas-side exit/entrance 12 of a single refrigerant flow path are grooved pipes, while heat transfer pipes leading to liquid-side exit/entrance 13 are smooth pipes thinner than the grooved pipes, and the ratio of the length of the smooth pipes is less than or equal to 25% of the total length. Therefore, when a zeotropic refrigerant mixture is used, the amount of required refrigerant can be reduced without deteriorating the heat transfer performance. The manufacture cost can also be reduced.
- Fig. 8 is another example of a side view of one refrigerant flow path portion extracted from outdoor heat exchanger 6 according to Embodiment 2.
- Heat transfer pipes 31 to 36 are arranged in an upper portion of outdoor heat exchanger 6 to form a first heat exchanger portion
- heat transfer pipes 37, 38 are arranged in a lower portion of outdoor heat exchanger 6 to form a second heat exchanger portion.
- respective fins 11 for the first heat exchanger portion and the second heat exchanger portions are separate from each other, and therefore, the first heat exchanger portion and the second heat exchanger portion can be adjusted independently of each other, in terms of the intervals between the heat transfer pipes and the gap between fins 11.
- the first heat exchanger portion of the grooved pipes and the second heat exchanger portion of the smooth pipes can be manufactured separately from each other, and therefore, the fin pitch and the interval between heat transfer pipes can be set appropriately depending on respective heat exchanging characteristics.
- Fig. 9 is an external view showing an example of an air conditioner equipped with the heat exchanger according to Embodiment 1 or 2.
- Air conditioner 100 is formed by connecting outdoor unit 1 and indoor unit 2 by gas pipe 3 and liquid pipe 4.
- the heat exchanger shown in connection with Embodiment 1 or 2 is used (not shown).
- the heat exchanger according to Embodiment 1 or 2 can be used as outdoor heat exchanger 6 and indoor heat exchanger 8, and therefore, the amount of refrigerant enclosed in air conditioner 100 can be reduced without deteriorating the heat exchange performance, which can contribute to reduction of the total GWP value and lessen the environmental load.
- восем ⁇ heat transfer pipes form a single refrigerant flow path, of which two pipes located near liquid-side exit/entrance 13 are smooth pipes.
- four heat transfer pipes form a single refrigerant flow path, for example, it is one heat transfer pipe located near liquid-side exit/entrance 13 that is a smooth pipe and, if six heat transfer pipes form a single refrigerant flow path, it is also one heat transfer pipe located near liquid-side exit/entrance 13 that is a smooth pipe.
- the length of the refrigerant flow path formed by the smooth pipe(s) is at least less than or equal to 25% of the total length, the effect of enhancing the heat transfer performance by the grooved pipes is not deteriorated.
- these advantageous effects are achieved not only for outdoor heat exchanger 6 but also for indoor heat exchanger 8.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Geometry (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
Description
- The present invention relates to a heat exchanger for an air conditioner.
- It has been pointed out that chlorofluorocarbons used as refrigerants for many refrigerators and air conditioners have a global warming effect, and various regulations have been enacted globally in order to reduce emissions of chlorofluorocarbons. For example, the 2016 Kigali Amendment to the Montreal Protocol requires that industrialized countries including Japan reduce the total GWP value, which is determined by multiplying the GWP (Global Warming Potential) by the refrigerant usage, to 15% by 2036, compared to that in 2011 to 2013.
- To comply with such regulations, it has been considered, in the refrigerator and air conditioner industry, to replace HFC refrigerants that are currently used widely, such as R410A (R32 : R125 = 50 wt% : 50 wt%, GWP = 2088) and R32 (GWP = 675), with refrigerants of lower GWP.
- More specifically, it has been considered to apply HFO refrigerants such as 2-3-3-3-tetrafluoropropene (R1234yf, GWP = 4), trans-1-3-3-3-tetrafluoropropene (R1234ze(E), GWP = 6), and 1-1-2-trifluoroethylene (R1123, GWP = 4); refrigerant mixtures of HFC refrigerants such as difluoromethane (R32, GWP = 675), pentafluoromethane (R125, GWP = 3500), and 1-1-1-2-tetrafluoroinethane (R134a, GWP = 1430), and the above-identified HFO refrigerants; or HC refrigerants such as propane (R290, GWP = 3) and isobutane (R600a, GWP = 4).
- Among these substance candidates, the refrigerant mixture of the HFC refrigerant and the HFO refrigerant is superior in terms of refrigeration capacity, theoretical COP, flammability, and toxicity, for example, and may be applicable to a wide variety of refrigerators and air conditioners. It is known that a mixture of multiple refrigerants having different boiling points, which is so-called zeotropic refrigerant mixture, exhibits properties different from those of pure refrigerants and azeotropic refrigerant mixtures. For example, in an evaporation process of zeotropic refrigerant mixtures, a lower-boiling-point component is evaporated first, and subsequently a higher-boiling-point component is evaporated, and therefore, the concentration of the higher-boiling-point component is higher in a liquid phase in the vicinity of the gas-liquid interface, which suppresses further boiling of the lower-boiling-point component. When the zeotropic refrigerant mixture is used, it is necessary to recover from such degradation in evaporation heat transfer.
- As a method for improving the heat exchange performance of an evaporator, a method is known that places an auxiliary heat exchanger at a refrigerant entrance side of a heat exchanger used as the evaporator, reduces the number of refrigerant flow paths of the auxiliary heat exchanger, and increases the pipe diameter thereof (
PTL 1, for example). - PTL 1:
Japanese Patent Laying-Open No. 2004-332958 - For such a heat exchanger configured like the above-cited patent literature, the auxiliary heat exchanger with the increased pipe diameter is located at a refrigerant exit side of the heat exchanger when used as a condenser. At the refrigerant exit side of the condenser, subcooled liquid flows, resulting in increase of the amount of refrigerant necessary for this refrigeration cycle due to the increased pipe diameter, and accordingly resulting in increase of the refrigerant usage.
- The present invention has been made to solve the problems as described above, and thereby obtain a heat exchanger for an air conditioner for which a zeotropic refrigerant mixture is used, and this heat exchanger, when used as an evaporator, enables reduction of the amount of required refrigerant without deteriorating the heat transfer performance.
- To achieve the above object, a heat exchanger according to the present disclosure includes:
- a first heat transfer pipe in which a heat medium flows and which has a plurality of grooves formed in an inner surface of the first heat transfer pipe; and
- a second heat transfer pipe having one end connected to one end of the first heat transfer pipe to form one heat medium flow path, the second heat transfer pipe being smaller in pipe diameter than the first heat transfer pipe, and having an inner surface shape providing a pressure loss per unit length smaller than that of the first heat transfer pipe.
- With the heat exchanger according to the present disclosure for which a zeotropic refrigerant mixture is used, the amount of required refrigerant can be reduced, without deteriorating the heat exchange performance. Moreover, the manufacture cost can also be reduced.
-
-
Fig. 1 is a refrigerant circuit diagram of an air conditioner including a heat exchanger according toEmbodiment 1. -
Fig. 2 is a front view of the heat exchanger according to Embodiment 1. -
Fig. 3 is a cross-sectional view of heat transfer pipes to be used for the heat exchanger according toEmbodiment 1. -
Fig. 4 is a characteristics plot showing an example of the evaporation heat transfer performance relative to the dryness fraction of refrigerant in a general grooved pipe. -
Fig. 5 is a characteristic plot showing an example of the pressure loss relative to the dryness fraction of refrigerant in a general grooved pipe. -
Fig. 6 is a Ph chart showing a refrigeration cycle operation of an air conditioner equipped with the heat exchanger according toEmbodiment 1. -
Fig. 7 is an example of a side view of one refrigerant flow path portion extracted from the heat exchanger according toEmbodiment 1. -
Fig. 8 is another example of a side view of one refrigerant flow path portion extracted from a heat exchanger according toEmbodiment 2. -
Fig. 9 is an external view of an air conditioner to which the heat exchanger according toEmbodiment - A heat exchanger and an air conditioner according to embodiments of the present disclosure are described hereinafter based on the drawings. It should be noted that the present invention is not limited by the embodiments.
-
Fig. 1 is a refrigerant circuit diagram showing an example of an air conditioner including a heat exchanger according toEmbodiment 1. The direction of refrigerant flow is indicated by solid and broken lines. InFig. 1 , anair conditioner 100 includes anoutdoor unit 1 and anindoor unit 2 that are connected to each other by agas pipe 3 and aliquid pipe 4 to form a single refrigerant circuit. In this refrigerant circuit, a refrigerant mixture made up of two or more types of refrigerants that are different from each other in boiling point is enclosed. -
Outdoor unit 1 is equipped with acompressor 5, anoutdoor heat exchanger 6, an expansion valve 7, and a four-way valve 9, andindoor unit 2 is equipped with an indoor heat exchanger 8. During cooling operation in which indoor heat exchanger 8 acts as an evaporator, refrigerant discharged fromcompressor 5 flows through four-way valve 9 intooutdoor heat exchanger 6, is reduced in pressure by expansion valve 7, and then flows out ofoutdoor unit 1. The refrigerant flowing throughliquid pipe 4 intoindoor unit 2 is evaporated in indoor heat exchanger 8 and flows out ofindoor unit 2. The refrigerant then flows throughgas pipe 3, returns tooutdoor unit 1, and is sucked again intocompressor 5. - During heating operation in which indoor heat exchanger 8 acts as a condenser, refrigerant discharged from
compressor 5 flows intoindoor unit 2 throughgas pipe 3 following a flow path setting for four-way valve 9. The refrigerant condensed by indoor heat exchanger 8 flows throughliquid pipe 4, returns tooutdoor unit 1, and is reduced in pressure in expansion valve 7. The refrigerant with the reduced pressure exchanges, inoutdoor heat exchanger 6, heat with outdoor air, and the refrigerant is accordingly evaporated and sucked again intocompressor 5 through four-way valve 9. -
Outdoor heat exchanger 6 and indoor heat exchanger 8 are each equipped with a fan (not shown), to force outdoor air and indoor air to flow tooutdoor heat exchanger 6 and indoor heat exchanger 8 and thereby increase the efficiency in exchanging heat between refrigerant and air. As the fan, for example, cross flow fan, propeller fan, turbo fan, or sirocco fan may be used. A single heat exchanger may be equipped with a plurality of fans, or a plurality of heat exchangers may be equipped with a single fan.Air conditioner 100 according toEmbodiment 1 has a minimum configuration required for enabling cooling operation and heating operation, and a gas-liquid separator, a receiver, an accumulator, and/or an inner heat exchanger, for example, may appropriately be added in the refrigerant circuit. -
Fig. 2 is a front view showing an example ofoutdoor heat exchanger 6 according to Embodiment 1.Outdoor heat exchanger 6 is made up of a plurality offins 11 stacked together at intervals of about 1.5 mm therebetween, andheat transfer pipes 31 to 38 extending through thesefins 11.Heat transfer pipes 31 to 38 are formed in a hairpin shape and closely fit infins 11 to allow heat transfer.Heat transfer pipes 31 to 38 have one end or both ends connected by a plurality ofU-shaped pipes 14 to form a single refrigerant flow path having a gas-side exit/entrance 12 and a liquid-side exit/entrance 13. During heating operation in whichoutdoor heat exchanger 6 acts as an evaporator, liquid-side exit/entrance 13 is an entrance of the refrigerant flow path while gas-side exit/entrance 12 is an exit of the refrigerant flow path. As also shown inFig. 1 , the refrigerant flow direction is the opposite direction during cooling operation, and therefore, whenoutdoor heat exchanger 6 acts as a condenser, liquid-side exit/entrance 13 is an exit of the refrigerant flow path while gas-side exit/entrance 12 is an entrance of the refrigerant flow path. -
Fig. 3 is a cross-sectional view of the heat transfer pipes used for the heat exchanger according to the embodiment.Heat transfer pipes 31 to 38 formingoutdoor heat exchanger 6 shown inFig. 2 include firstheat transfer pipes 31 to 36, and the first heat transfer pipes are grooved pipes having peaks and valleys on the pipe inner surface as shown for example inFig. 3 (a) , have one end located at gas-side exit/entrance 12, and extend throughfins 11 to form a first heat exchanger portion.Heat transfer pipes Fig. 3 (b) , have one end located at liquid-side exit/entrance 13, and extend throughfins 11 to form a second heat exchanger portion.Heat transfer pipes heat transfer pipes 31 to 36 (D1 > D2). - The shape of the grooves in
heat transfer pipes 31 to 36 is not limited. Specifically, there is no particular limitation on the inner diameter, the number of fins in the pipes (hereinafter intra-pipe fins), the height of the intra-pipe fins, the helix angle of the intra-pipe fins, and the area extension ratio, for example. - The type of the zeotropic refrigerant mixture (hereinafter referred to as "refrigerant" as long as it is not necessary in terms of context to distinguish between zeotropic refrigerant mixture, pure refrigerant, and azeotropic refrigerant mixture) to be enclosed in
air conditioner 100 is not particularly limited. For example, the refrigerant to be used may be a refrigerant mixture of an HFC refrigerant such as difluoromethane (R32, GWP = 675), pentafluoromethane (R125, GWP = 3500), or 1-1-1-2-tetrafluoromethane (R134a, GWP = 1430), and an HFO refrigerant such as 2-3-3-3-tetrafluoropropene (R1234yf, GWP = 4), trans-1-3-3-3-tetrafluoropropene (R1234ze(E), GWP = 6), 1-1-2-trifluoroethylene (R1123, GWP = 4), difluoroethylene (R1132a, GWP = 1), trans-difluoroethylene (R1132(E), GWP = 1), or 1-1-1-4-4-4-hexafluoro-2-butene (R1336mzz(Z), GWP = 2), or a refrigerant mixture of an HFCO refrigerant such as trans-1-chloro-3-3-3-trifluoropropene (R1233zd, GWP = 1), or cis-1-chloro-2-3-3-3-tetrafluoropropene (R1224yd(Z), GWP = 1), and an HC refrigerant such as propane (R290, GWP = 3), or isobutane (R600a, GWP = 4), and the like. -
Fig. 4 is a characteristic plot showing an example of the intra-pipe evaporation heat transfer performance relative to the dryness fraction of refrigerant in a general grooved pipe. The vertical axis indicates the evaporation heat transfer coefficient of the grooved pipe, represented by a relative value with respect to the evaporation heat transfer coefficient of a smooth pipe. As for the refrigerant, respective characteristics of two different refrigerants, i.e., a single refrigerant and a zeotropic refrigerant mixture, are plotted by a broken line and a solid line, respectively. - As shown in
Fig. 4 , for the single refrigerant, the grooved pipe exhibits an evaporation heat transfer coefficient of three or more times higher than that of the smooth pipe, regardless of the refrigerant dryness fraction, and thus significantly contributes to improvement of the heat exchange performance. In contrast, when the zeotropic refrigerant mixture is used, improvement of the evaporation heat transfer coefficient relative to the smooth pipe is not significantly large, unlike the one achieved for the single refrigerant. In particular, in the region of a low refrigerant dryness fraction of 0.4 or less, the evaporation heat transfer coefficient of the grooved pipe is substantially identical to the evaporation heat transfer coefficient of the smooth pipe, and thus fails to contribute to improvement of the heat exchange performance. -
Fig. 5 is a characteristic plot showing an example of the pressure loss relative to the dryness fraction of refrigerant in a general grooved pipe. The vertical axis indicates the pressure loss of the grooved pipe, represented by a relative value with respect to the pressure loss of a smooth pipe. The broken line represents the pressure loss for a single refrigerant, and the solid line represents the pressure loss for a zeotropic refrigerant mixture. - As shown in
Fig. 5 , the pressure loss of the grooved pipe is large relative to the pressure loss of the smooth pipe, regardless of the refrigerant dryness fraction, and particularly large in the region of a refrigerant dryness fraction of 0.3 to 0.5. This phenomenon is substantially the same for both the single refrigerant and the zeotropic refrigerant mixture. For the zeotropic refrigerant mixture, however, the rate of increase of the pressure loss is larger. It is seen fromFigs. 4 and 5 that although use of the grooved pipe for the heat exchanger improves the heat transfer performance, the heat transfer performance is not improved and only the pressure loss is increased for a refrigerant dryness fraction of 0.4 or less. -
Fig. 6 is a Ph chart showing a refrigeration cycle operation ofair conditioner 100 according toEmbodiment 1. The vertical axis indicates the pressure, the horizontal axis indicates the specific enthalpy, and XO is a saturation line connecting points where refrigerant is saturated liquid or saturated gas. State A, State B, State C, and State D are respective entrance states of a process of compression, condensation, expansion, and evaporation that form a refrigeration cycle. While the refrigeration cycle shown inFig. 6 is not limited to cooling operation or heating operation, the refrigeration cycle operation is described first for the heating operation in the following. - Low-temperature low-pressure gas refrigerant (State A) at a suction position of
compressor 5 is increased in pressure bycompressor 5 into high-temperature high-pressure discharged gas (State B). The discharged gas is condensed in indoor heat exchanger 8 acting as a condenser into high-pressure subcooled liquid (State C). The refrigerant is subsequently reduced in pressure by expansion valve 7 into low-pressure gas-liquid two-phase refrigerant (State D). - In the chart, X1 is a line of constant dryness fraction where the refrigerant dryness fraction is 0.2. It is known that, at the entrance of the evaporator, the refrigerant (State D) has a dryness fraction of approximately 0.2, for a condensation temperature in a range of 40°C± 10°C and an evaporation temperature in a range of 0°C±10°C that are general operating conditions of air conditioning. In other words, in an evaporation process from State D to State A in a general air conditioner, the refrigerant dryness fraction changes from 0.2 to approximately 1.0 under most operating conditions. In the present embodiment, in
outdoor heat exchanger 6 shown inFig. 2 , the low-pressure gas-liquid two-phase refrigerant in State D absorbs heat from outdoor air until being superheated slightly, and returns to State A to thereby complete a single refrigeration cycle. - As set forth above, the heat transfer coefficient improvement effect to be produced by the grooved pipe is not exhibited for a dryness fraction change from 0.2 to 0.4 in a dryness fraction change of 0.8 (= 1.0 0.2) in this evaporation process. In other words, when the heat exchanger is used as an evaporator, it is unnecessary to employ the grooved pipe, which is means for improving the heat exchange performance, for a length of 25% (= 0.2/0.8) from liquid-side exit/
entrance 13 serving as a refrigerant entrance. Therefore, inEmbodiment 1 as shown inFig. 2 ,heat transfer pipes entrance 13 ofoutdoor heat exchanger 6 are configured in the form of smooth pipes. The smooth pipe is lower in cost than the grooved pipe, and therefore, the manufacture cost ofoutdoor heat exchanger 6 can be reduced. - Moreover, if it is used under an extremely low evaporation temperature condition, refrigerator oil dissolved in the liquid refrigerant may separate from the refrigerant and stay in the vicinity of the wall of the heat transfer pipe. Stay of the refrigerator oil may deteriorate the reliability of
compressor 5, and should therefore be avoided as much as possible. Thus, for the second heat exchanger portion located near liquid-side exit/entrance 13 where a large amount of liquid refrigerant is present, smooth pipes in which less friction occurs can be employed to reduce the amount of staying refrigerator oil, and thereby improve the reliability of the air conditioner. - Next, cooling operation is described. During cooling operation, indoor heat exchanger 8 acts as an evaporator and
outdoor heat exchanger 6 acts as a condenser. High-temperature high-pressure gas refrigerant in State B is discharged fromcompressor 5, flows intooutdoor heat exchanger 6 to exchange heat with outdoor air, and is then condensed into subcooled liquid refrigerant in State C. In an SC portion which is the last stage of this condensation process, i.e., SC portion that is a region after refrigerant becomes saturated liquid, most of the amount of refrigerant necessary for this refrigeration cycle is concentrated. - In
outdoor heat exchanger 6 inEmbodiment 1,heat transfer pipes air conditioner 100 is also reduced, which can contribute to reduction of the total GWP value and can lessen the environmental load. - Moreover, the smaller diameter of
heat transfer pipes -
Fig. 7 is an example of a side view of one refrigerant flow path portion extracted from the heat exchanger according toEmbodiment 1. WhileFig. 2 shows the heat exchanger arranged in a single line,Fig. 7 shows thatheat transfer pipes 31 to 38 forming one refrigerant flow path are arranged in two lines in the direction of air flow. Of eightheat transfer pipes 31 to 38, sixheat transfer pipes 31 to 36 are grooved pipes and twoheat transfer pipes entrance 13 is formed by the smooth pipes. InFig. 7 , a first heat exchanger portion formed byheat transfer pipes 31 to 36 and a second heat exchanger portion formed byheat transfer pipes - As seen from the above, in the heat exchanger according to
Embodiment 1, heat transfer pipes leading to gas-side exit/entrance 12 of a single refrigerant flow path are grooved pipes, while heat transfer pipes leading to liquid-side exit/entrance 13 are smooth pipes thinner than the grooved pipes, and the ratio of the length of the smooth pipes is less than or equal to 25% of the total length. Therefore, when a zeotropic refrigerant mixture is used, the amount of required refrigerant can be reduced without deteriorating the heat transfer performance. The manufacture cost can also be reduced. -
Fig. 8 is another example of a side view of one refrigerant flow path portion extracted fromoutdoor heat exchanger 6 according toEmbodiment 2.Heat transfer pipes 31 to 36 are arranged in an upper portion ofoutdoor heat exchanger 6 to form a first heat exchanger portion, andheat transfer pipes outdoor heat exchanger 6 to form a second heat exchanger portion. As shown inFig. 8 ,respective fins 11 for the first heat exchanger portion and the second heat exchanger portions are separate from each other, and therefore, the first heat exchanger portion and the second heat exchanger portion can be adjusted independently of each other, in terms of the intervals between the heat transfer pipes and the gap betweenfins 11. - As seen from the above, for the heat exchanger according to
Embodiment 2, the first heat exchanger portion of the grooved pipes and the second heat exchanger portion of the smooth pipes can be manufactured separately from each other, and therefore, the fin pitch and the interval between heat transfer pipes can be set appropriately depending on respective heat exchanging characteristics. -
Fig. 9 is an external view showing an example of an air conditioner equipped with the heat exchanger according toEmbodiment Air conditioner 100 is formed by connectingoutdoor unit 1 andindoor unit 2 bygas pipe 3 andliquid pipe 4. For bothoutdoor heat exchanger 6 housed inoutdoor unit 1 andindoor heat exchanger 9 housed inindoor unit 2, the heat exchanger shown in connection withEmbodiment - As seen from the above, for
air conditioner 100 illustrated in connection withEmbodiment 3, the heat exchanger according toEmbodiment outdoor heat exchanger 6 and indoor heat exchanger 8, and therefore, the amount of refrigerant enclosed inair conditioner 100 can be reduced without deteriorating the heat exchange performance, which can contribute to reduction of the total GWP value and lessen the environmental load. - According to
Embodiments entrance 13 are smooth pipes. However, if four heat transfer pipes form a single refrigerant flow path, for example, it is one heat transfer pipe located near liquid-side exit/entrance 13 that is a smooth pipe and, if six heat transfer pipes form a single refrigerant flow path, it is also one heat transfer pipe located near liquid-side exit/entrance 13 that is a smooth pipe. As long as the length of the refrigerant flow path formed by the smooth pipe(s) is at least less than or equal to 25% of the total length, the effect of enhancing the heat transfer performance by the grooved pipes is not deteriorated. Moreover, these advantageous effects are achieved not only foroutdoor heat exchanger 6 but also for indoor heat exchanger 8. - The features illustrated in connection with the above embodiments are an example of the details of the present disclosure, and may be combined with other known techniques, or may partially be omitted or changed without going beyond the scope of the present disclosure.
- 1 outdoor unit; 2 indoor unit; 3 gas pipe; 4 liquid pipe; 5 compressor; 6 outdoor heat exchanger; 7 expansion valve; 8 indoor heat exchanger; 9 four-way valve; 11 fin; 12 gas-side exit/entrance; 13 liquid-side exit/entrance; 14 U-shaped pipe; 31-36 grooved pipe; 37, 38 smooth pipe; 100 air conditioner
Claims (6)
- A heat exchanger comprising:a first heat transfer pipe in which a heat medium flows and which has a plurality of grooves formed in an inner surface of the first heat transfer pipe; anda second heat transfer pipe having one end connected to one end of the first heat transfer pipe to form one heat medium flow path, the second heat transfer pipe being smaller in pipe diameter than the first heat transfer pipe, and having an inner surface shape providing a pressure loss per unit length smaller than that of the first heat transfer pipe.
- The heat exchanger according to claim 1, whereinwhen the heat exchanger acts as an evaporator, another end of the second heat transfer pipe is an entrance for the heat medium, andwhen the heat exchanger acts as a condenser, another end of the first heat transfer pipe is an entrance for the heat medium.
- The heat exchanger according to claim 2, wherein the heat medium is a zeotropic refrigerant mixture.
- The heat exchanger according to claim 3, wherein the second heat transfer pipe has a length of less than or equal to 25% of a length of the heat medium flow path.
- The heat exchanger according to any one of claims 1 to 4, comprising a first heat exchanger portion formed by the first heat transfer pipe, and a second heat exchanger portion formed by the second heat transfer pipe and separate from the first heat exchanger portion.
- An air conditioner comprising the heat exchanger according to any one of claims 1 to 5, the heat exchanger being used either as an outdoor heat exchanger or an indoor heat exchanger.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2020/009421 WO2021176651A1 (en) | 2020-03-05 | 2020-03-05 | Heat exchanger and air conditioner |
Publications (2)
Publication Number | Publication Date |
---|---|
EP4116642A1 true EP4116642A1 (en) | 2023-01-11 |
EP4116642A4 EP4116642A4 (en) | 2023-04-05 |
Family
ID=77614218
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20923061.4A Pending EP4116642A4 (en) | 2020-03-05 | 2020-03-05 | Heat exchanger and air conditioner |
Country Status (4)
Country | Link |
---|---|
US (1) | US20230043875A1 (en) |
EP (1) | EP4116642A4 (en) |
JP (1) | JP7414951B2 (en) |
WO (1) | WO2021176651A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2024069896A1 (en) * | 2022-09-29 | 2024-04-04 | 日立ジョンソンコントロールズ空調株式会社 | Air conditioner |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06281293A (en) * | 1993-03-31 | 1994-10-07 | Toshiba Corp | Heat exchanger |
JP2979926B2 (en) * | 1993-10-18 | 1999-11-22 | 株式会社日立製作所 | Air conditioner |
JPH0875384A (en) * | 1994-07-01 | 1996-03-19 | Hitachi Ltd | Heat transfer tube for non-azeotrope refrigerant, heat exchanger using the same tube, assembling method and refrigerating air conditioner using the same exchanger |
JPH08145593A (en) * | 1994-11-24 | 1996-06-07 | Sanyo Electric Co Ltd | Heat exchanger |
WO1999031444A1 (en) * | 1997-12-16 | 1999-06-24 | Matsushita Electric Industrial Co., Ltd. | Airconditioner using inflammable refrigerant |
JP2001330388A (en) * | 2000-05-19 | 2001-11-30 | Matsushita Electric Ind Co Ltd | Heat exchanger unit |
KR20020038002A (en) * | 2000-11-16 | 2002-05-23 | 구자홍 | Conductible tube for evaporator |
JP4297250B2 (en) | 2003-04-30 | 2009-07-15 | 東芝キヤリア株式会社 | Air conditioner heat exchanger |
JP2009257744A (en) * | 2008-03-25 | 2009-11-05 | Daikin Ind Ltd | Refrigerating device |
JP2015158303A (en) * | 2014-02-24 | 2015-09-03 | 三菱電機株式会社 | heat exchanger and refrigeration cycle device |
CN107003081A (en) * | 2015-01-09 | 2017-08-01 | 三菱电机株式会社 | Heat exchanger and the refrigerating circulatory device with the heat exchanger |
CN108291780A (en) * | 2015-11-23 | 2018-07-17 | 开利公司 | Heat exchanger |
US10088250B2 (en) * | 2016-01-12 | 2018-10-02 | Hamilton Sundstrand Corporation | Heat exchangers |
-
2020
- 2020-03-05 JP JP2022504883A patent/JP7414951B2/en active Active
- 2020-03-05 US US17/790,299 patent/US20230043875A1/en active Pending
- 2020-03-05 EP EP20923061.4A patent/EP4116642A4/en active Pending
- 2020-03-05 WO PCT/JP2020/009421 patent/WO2021176651A1/en unknown
Also Published As
Publication number | Publication date |
---|---|
JP7414951B2 (en) | 2024-01-16 |
US20230043875A1 (en) | 2023-02-09 |
JPWO2021176651A1 (en) | 2021-09-10 |
EP4116642A4 (en) | 2023-04-05 |
WO2021176651A1 (en) | 2021-09-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5423089B2 (en) | Refrigeration equipment | |
KR0142506B1 (en) | Airconditioner employing non-azeotrope refrigerant | |
EP2317269B1 (en) | Heat exchanger, refrigerating cycle apparatus, and air conditioning apparatus | |
KR101797176B1 (en) | Dual pipe structure for internal heat exchanger | |
WO2011086881A1 (en) | Heat transfer tube for heat exchanger, heat exchanger, refrigeration cycle device, and air conditioning device | |
JP2000161805A (en) | Refrigerating apparatus | |
JP5800909B2 (en) | Heat exchanger and refrigeration cycle apparatus using the heat exchanger | |
JPWO2017221400A1 (en) | Refrigeration cycle equipment | |
WO2021065913A1 (en) | Evaporator and refrigeration cycle device equipped with same | |
EP4155646A1 (en) | Heat exchanger, outdoor unit, and refrigeration cycle device | |
EP4116642A1 (en) | Heat exchanger and air conditioner | |
JP6529604B2 (en) | Refrigeration cycle device | |
WO2018008129A1 (en) | Refrigeration cycle device | |
JP5646257B2 (en) | Refrigeration cycle equipment | |
US6739143B1 (en) | Refrigerating device | |
US11371758B2 (en) | Refrigeration cycle apparatus | |
CN113227672A (en) | Refrigeration cycle device | |
WO2015125525A1 (en) | Heat exchanger and refrigerating cycle device | |
US20220299276A1 (en) | Refrigeration cycle apparatus | |
WO2016075851A1 (en) | Heat pump apparatus | |
WO2020202492A1 (en) | Heat exchanger and air conditioner | |
JP2010249484A (en) | Heat exchanger and refrigerating cycle device | |
WO2017145243A1 (en) | Refrigeration cycle apparatus | |
JP2000257974A (en) | Refrigerating system | |
JP2020173056A (en) | Refrigeration cycle device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20220819 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 20230303 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: F28D 21/00 20060101ALI20230227BHEP Ipc: F28F 1/06 20060101ALI20230227BHEP Ipc: F28F 13/18 20060101ALI20230227BHEP Ipc: F28F 1/32 20060101ALI20230227BHEP Ipc: F28F 1/00 20060101ALI20230227BHEP Ipc: F28D 1/047 20060101ALI20230227BHEP Ipc: F25B 13/00 20060101ALI20230227BHEP Ipc: F28F 1/40 20060101ALI20230227BHEP Ipc: F25B 1/00 20060101ALI20230227BHEP Ipc: F28F 13/06 20060101ALI20230227BHEP Ipc: F28F 13/02 20060101ALI20230227BHEP Ipc: F25B 39/04 20060101ALI20230227BHEP Ipc: F25B 39/02 20060101AFI20230227BHEP |
|
DAV | Request for validation of the european patent (deleted) | ||
DAX | Request for extension of the european patent (deleted) | ||
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: GRANT OF PATENT IS INTENDED |
|
INTG | Intention to grant announced |
Effective date: 20240521 |