Patent Grant
12228350
The present application is based on PCT filing PCT/JP2019/044086, filed Nov. 11, 2019, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a heat exchanger and a refrigeration cycle apparatus. In particular, it relates to a heat exchanger including a combination of corrugated fins and flat heat exchange tubes and an air-conditioning apparatus including the heat exchanger.
For example, a corrugated finned tube heat exchanger has been widely used in which corrugated fins are each provided between associated ones of planar portions of a plurality of flat heat exchange tubes connected between a pair of headers through which refrigerant passes. Air passes as an air stream through between the flat heat exchange tubes between which an associated corrugated fin is provided. In such a heat exchanger, a surface temperature of the corrugated fin and/or the flat heat exchange tubes may fall below freezing. When the surface temperature falls, the moisture in air close to the surface is precipitated as water, and furthermore, the temperature falls below freezing, the water freezes. In view of this, in some heat exchangers, in order to drain such water, slits are provided as spaces in fins, and water deposited on a surface, that is, water as which moisture is precipitated on the surface, is let out through the slits (see, for example, Patent Literature 1).
An existing heat exchanger has a structure that lets out water deposited on a surface of a corrugated fin as described above. If the water remains on the corrugated fin, however, it is hard to let out the remaining water. For example, the remaining water freezes, and obstructs air that passes through the heat exchanger, thereby deteriorating the heat exchange performance of the corrugated fin.
The present disclosure is applied to solve the above problem, and relates to a heat exchanger and a refrigeration cycle apparatus that are capable of improving the drainage performance of a corrugated fin.
A heat exchanger according to an embodiment of the present disclosure includes: a plurality of flat heat exchange tubes each having an elongated cross section and planar outer surfaces that face each other, the flat heat exchange tubes each including a fluid flow passage therein; and a plurality of corrugated fins each formed in the shape of waves and provided between associated adjacent ones of the flat heat exchange tubes, each of the corrugated fins having ridge portions that correspond to ridges of the waves and that are joined to the associated flat heat exchange tubes, the corrugated fin having portions that are located between the ridge portions and formed as fins that are arranged in a height direction. The fins include respective drain slits each of which allows water on an associated one of the fins to be drained therethrough, and end portions of the drain slits of adjacent ones of the fins in a horizontal direction are located at different positions in the drain slits, the adjacent fins being adjacent to each other in the height direction.
A refrigeration cycle apparatus according to another embodiment of the present disclosure includes the heat exchanger described above.
The heat exchanger according to the embodiment of the present disclosure includes the corrugated fin in which end portions of the drain slits of adjacent ones of the fins in a horizontal direction are located at different positions in the drain slits in the height direction. Thus, water from the upper one of the adjacent fins can be drained after being made to join water on the lower one of the adjacent fins. Therefore, it is possible to reduce remaining water on the fins, thus prevent freezing, etc., and further improve the heat exchange performance of the corrugated fin.
A heat exchanger and an air-conditioning apparatus according to embodiments will be described below with reference to the accompanying drawings, etc. In each of figures to be referred to below, components that are the same as or equivalent to those in a previous figure or previous figures are denoted by the same reference signs, and the same is true of the entire text of the present specification. Configurations of components described in the entire text of the specification are merely examples, and the descriptions of the configurations are not limiting. In particular, in the case where components are combined, it is not limited to the case where components according to the same embodiment are combined. A component in an embodiment can be applied to another embodiment. The “upper side” and “lower side” in the following description correspond to the upper side and lower side of each of the figures, respectively. In addition, in order that the embodiments be easily understood, terms related to directions (such as “right”, “left”, front”, and “rear”) are used as appropriate. However, these terms are used only for explanation, that is, they do not limit the contents of the embodiments. Furthermore, with respect to temperature and humidity, whether each of values is higher or lower is relatively determined based on the state, operation, etc., of an apparatus, etc., not based on the relationship between the value and an absolute value. In the figures, the relationships in size between components as illustrated in the figures may be different from that between those of actual components.
The headers 3 are tubes that are connected to other devices included in a refrigeration cycle apparatus by pipes, that allow inflow and outflow of refrigerant that is fluid serving as a heat exchange medium, and that cause the refrigerant to branch off or join each other. The plurality of flat heat exchange tubes 1 are arranged in parallel between the headers 3 in such a manner as to extend in a direction perpendicular to the headers 3. As illustrated in
Each of the flat heat exchange tubes 1 is a heat exchange tube that has an elongated cross section, has planar outer surfaces extending in a depth direction, which is the flow direction of air, on a longitudinal side of an elongated shape, and has curved outer surfaces on a width direction orthogonal to the longitudinal direction. The flat heat exchange tube 1 is a porous flat heat exchange tube having a plurality of holes that serve as flow passages for refrigerant. In Embodiment 1, the holes in the flat heat exchange tube 1 are refrigerant flow passages that extend between the headers 3 to face in the height direction. The flat heat exchange tubes 1 are arranged at regular intervals in the horizontal direction such that the outer surfaces of the flat heat exchange tubes 1 in the longitudinal direction thereof face each other. When the heat exchanger in Embodiment 1 is manufactured, the flat heat exchange tubes 1 are inserted into insertion holes (not illustrated) in the headers 3, and are brazed and joined thereto. As brazing material for the brazing, for example, a brazing material including aluminum is used.
When the heat exchanger 10 is used as a condenser, high-temperature and high-pressure refrigerant flows through the refrigerant flow passages in the flat heat exchange tube 1. When the heat exchanger 10 is used as an evaporator, low-temperature and low-pressure refrigerant flows through the refrigerant flow passages in the flat heat exchange tube 1. The refrigerant flows from an external device (not illustrated) into one of the headers 3 through a pipe (not illustrated) for use in supplying the refrigerant to the heat exchanger 10. The refrigerant that has flowed into the above one of the headers 3 is split into refrigerant streams, and the refrigerant streams flow through respective flat heat exchange tubes 1. In the flat heat exchange tubes 1, heat exchange is performed between the refrigerant that passes through the tubes and outside air that is the atmosphere that is present outside the tubes. At that time, the refrigerant transfers heat into the atmosphere or receives heat from the atmosphere while passing through the flat heat exchange tubes 1. When the temperature of the refrigerant is higher than that of the outside air, the refrigerant transfers heat from itself into the outside air. When the temperature of the refrigerant is lower than that of the outside air, the refrigerant receives heat from the atmosphere. The refrigerant that has passes through the flat heat exchange tubes 1 and exchanged the heat flows into the other header 3 and joins refrigerant in the other header 3. Then, the refrigerant flows through a pipe (not illustrated) connected to the other header 3 and returns to the external device (not illustrated).
Between a space between any adjacent two of flat surfaces of the flat heat exchange tubes 1, an associated one of the corrugated fins 2 is provided. The corrugated fin 2 is provided to increase a heat transfer area between the refrigerant and the outside air. The corrugated fin 2 is formed by performing corrugating processing on a plate material such that the plate material is bent and corrugated in the shape of an accordion by wining in which mountain fold and valley fold are repeated. It should be noted that bent portions of the corrugated plate material are ridge portions. In Embodiment 1, the ridge portions of the corrugated fin 2 are arranged in the height direction.
Portions of the corrugated fin that are located at mountainsides between the ridge portions of the corrugated fin 2 are fins 21. Each of the fins 21 includes louvers 22 and a drain slit 23. In the fin 21, the louvers 22 are arranged in the depth direction that is the flow direction of air at the fin 21. Thus, the louvers 22 are arranged along the air stream. The louvers 22 include slits that allow air to pass therethrough and plate portions that guides the air passing through the slits. The drain slit 23 is provided at a position corresponding to a central portion of the associated flat heat exchange tube 1 in the depth direction in the fin 21. The drain slit 23 extends to have a rectangular shape in the horizontal direction. It should be noted that in the drain slits 23 of adjacent ones of the fins 21 in the heat exchanger 10 in Embodiment 1 in the height direction, center positions of the drain slits 23 in the horizontal direction are offset from each other, and the positions of end portions of the drain slits 23 in the horizontal direction are also offset from each other, as described below. The corrugated fins 2 will be described in more details later.
As illustrated in
The compressor 210 compresses sucked refrigerant and discharges the compressed refrigerant. Although it is not particularly limited, it is possible to change the capacity of the compressor 210 by arbitrarily changing the operation frequency thereof using, for example, an inverter circuit. The four-way valve 220 is, for example, a valve that switches the flow direction of refrigerant between the flow direction of the refrigerant for a cooling operation and that for a heating operation.
The outdoor heat exchanger 230 causes heat exchange to be performed between the refrigerant and the outdoor air. For example, in the heating operation, the outdoor heat exchanger 230 operates as an evaporator and causes the refrigerant to evaporate and gasify; and in the cooling operation, the outdoor heat exchanger 230 operates as a condenser and causes the refrigerant to condense and liquefy. The outdoor fan 240 sends outdoor air into the outdoor heat exchanger 230 and promotes the heat exchange at the outdoor heat exchanger 230.
The indoor heat exchanger 110 causes heat exchange to be performed between the refrigerant and, for example, indoor air to be conditioned. In the heating operation, the indoor heat exchanger 110 operates as a condenser and causes the refrigerant to condense and liquefy; and in the cooling operation, the indoor heat exchanger 110 operates as an evaporator and causes the refrigerant to evaporate and gasify.
The indoor unit 100 includes the indoor heat exchanger 110, an expansion valve 120, and an indoor fan 130. The expansion valve 120, such as a throttle device, decompresses the refrigerant to expand the refrigerant. For example, when the expansion valve 120 is an electronic expansion valve or a similar valve, the expansion valve 120 adjusts the opening degree in response to an instruction given from a controller (not illustrated) or a similar device. The indoor heat exchanger 110 causes heat exchange to be performed between the refrigerant and air in an indoor space that is air-conditioned space. For example, in the heating operation, the indoor heat exchanger 110 operates as a condenser and causes the refrigerant to condense and liquefy; and in the cooling operation, the indoor heat exchanger operates as an evaporator and causes the refrigerant to evaporate and gasify. The indoor fan 130 sends indoor air into the indoor heat exchanger 110 in order that the indoor air that has passed through the indoor heat exchanger 110 be supplied into the indoor space.
Next, the operation of each of components in the air-conditioning apparatus will be described based on the flow of the refrigerant. First of all, it will be described how each component in the refrigerant circuit operates in the heating operation, based on the flow of the refrigerant. High-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. While passing through the indoor heat exchanger 110, gas refrigerant exchanges heat with, for example, air in an air-conditioned space to condense and liquefied. Then, the refrigerant passes through the expansion valve 120. When passing through the expansion valve 120, the refrigerant is decompressed to change into two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant passes through the outdoor heat exchanger 230. In the outdoor heat exchanger 230, the refrigerant exchanges heat with outdoor air sent from the outdoor fan 240 to evaporate and gasify. Then, the refrigerant passes through the four-way valve 220 and is re-sucked into the compressor 210. In the above manner, the refrigerant in the air-conditioning apparatus circulates, and air conditioning related to heating is performed.
Next, the cooling operation will be described. High-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230. Then, the refrigerant passes through the outdoor heat exchanger 230, exchanges heat with the outdoor air supplied by the outdoor fan 240, and thus condenses to change into liquid refrigerant. The liquid refrigerant passes through the expansion valve 120. While passing through the expansion valve 120, the refrigerant is decompressed to change into two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant passes through the indoor heat exchanger 110. In the indoor heat exchanger 110, for example, the refrigerant exchanges heat with air in the air-conditioned space, and thus evaporates to change into gas refrigerant. The gas refrigerant passes through the four-way valve 220 and is re-sucked into the compressor 210. In the above manner, the refrigerant in the air-conditioning apparatus circulates, and air conditioning related to heating is performed.
As described above, when the heat exchanger 10 operates as the evaporator, the temperatures of the surfaces of the flat heat exchange tubes 1 and the corrugated fins 2 are lower than that of air that passes through the heat exchanger 10. Therefore, with moisture in the air, condensation occurs on the surfaces of the flat heat exchange tubes 1 and the corrugated fins 2, and condensed water 4 is deposited.
In each of the corrugated fins 2, condensed water 4 that condenses on the surface of a fin 21 flows into the drain slit 23 of the fin 21 and falls down toward a lower fin 21. At that time, in a region where the amount of the condensed water 4 is large, the condensed water 4 easily flows on the surface of the fin 21 and easily falls down through the drain slit 23. On the other hand, in a region where the amount of the condensed water 4 is small, the condensed water 4 tends to be retained and remain on the surface of the fin 21, and does not easily flow.
As described above, in the heat exchanger 10 according to Embodiment 1, the drain slit 23 in one of fins 21 that are adjacent to each other in the height direction is located such that the position of the above drain slit 23 in the horizontal direction is displaced from that of the drain slit 23 in the other fin 21 in the horizontal direction. Although it is not particularly limited, in the heat exchanger 10 in Embodiment 1, it is assumed that drain slits 23 whose central positions are the same as each other are provided on a periodic basis in the single corrugated fin 2.
By virtue of the above configuration, from an end portion of the drain slit 23 in an upper fin 21 in the horizontal direction, the condensed water 4 falls down onto a lower fin 21. The condensed water 4 that has fallen onto the lower fin 21 joins condensed water 4 that is retained on a surface of the lower fin 21 and does not easily flow. Because of this confluence, the resultant condensed water 4 easily flows down through the drain slit 23 of the lower fin 21 since the amount of the resultant condensed water 4 is increased. As a result, the amount of the condensed water 4 retained on the surface of the fin 21 decreases, and the condensed water 4 can be efficiently drained.
In the heat exchanger 10 according to Embodiment 1, for example, as illustrated in
As described above, in the heat exchanger 10 according to Embodiment 1, in each of the corrugated fins 2, the drain slits 23 in at least adjacent ones of the fins 21 that are adjacent to each other in the height direction are offset from each other in the horizontal direction. Therefore, condensed water 4 that has fallen from the drain slit 23 in the upper one of the above adjacent fins 21 can join condensed water 4 that is retained on the surface of the lower one of the adjacent fins 21 and that does not easily flow. Because of this confluence, the resultant condensed water 4 can be drained from the drain slit 23 in the lower fin 21. It is therefore possible to reduce the amount of the condensed water 4 that is retained on the surface of the fin 21, and thus reduce deterioration of the heat exchange performance.
The distances between the drain slits 23 in the fins 21 in the corrugated fin 2 may be equal to each other, or as illustrated in
Each of the corrugated fins 2 in the heat exchanger 10 according to Embodiment 3 is provided between associated flat heat exchange tubes 1A and between associated flat heat exchange tubes 1B, and is brazed and joined to the flat heat exchange tubes 1A and 1B. In each of the fins 21 in the corrugated fin 2, a first drain slit 23A is provided in an area between the flat heat exchange tubes 1A, and a second drain slit 23B is provided in an area between the flat heat exchange tubes 1B,
In the above manner, by adjusting the distances between the first drain slits 23A and those between the second drain slits 23B in the fins 21, the lengths of these slits, etc., the drainage performance of the fins 21 on the windward side, where the heat exchange performance is higher than that on the leeward side, can be improved, and the heat exchange performance on the leeward side, where the heat exchange performance is lower than that on the windward side, can also be improved. It is therefore possible to reduce deterioration of the drainage performance and the heat exchange performance. Furthermore, since the heat exchange performance on the leeward side is also improved, the difference in heat exchange performance between the fins 21 can be reduced. Thus, the difference in thickness between frost that forms on the surfaces of the fins 21 under a condition where the air temperature is low can be reduced, and the heat exchange performance under the above low-temperature air condition can be improved.
It should be noted that the position of the drain slit 23 in the depth direction is not limited to a specific one. For example, as illustrated in
As described above, according to Embodiment 3, in the heat exchanger 10 in which a plurality of rows of flat heat exchange tubes 1 are arranged in the depth direction along the flow of air, in each of the rows, the drain slit 23 is provided in the area between the flat heat exchange tubes 1. To be more specific, in the above case, the distance between the first drain slits 23A and that between the second drain slits 23B in each row, the silt length, etc., are adjusted. As a result, in a combination of the above slits, that is, the first drain slits 23A and the second drain slits 23B, deterioration of the drainage performance and the heat exchange performance is reduced.
The center positions of first drain slits 23Aa to 23Ac in corrugated fins 2a to 2c as illustrated in
1, 1A, 1B: flat heat exchange tube, 2, 2a, 2b, 2c: corrugated fin, 3, 3A, 3B: header, 4: condensed water, 10: heat exchanger, 21: fin, 22: louver, 23: drain slit, 23A, 23Aa, 23Ab, 23Ac: first drain slit, 23B, 23Ba, 23Bb, 23Bc: second drain slit, 23C, 23Ca, 23Cb, 23Cc: third drain slit, 100: indoor unit, 110: indoor heat exchanger, 120: expansion valve, 130: indoor fan, 200: outdoor unit, 210: compressor, 220: four-way valve, 230: outdoor heat exchanger, 240: outdoor fan, 300: gas refrigerant pipe, 400: liquid refrigerant pipe, 500: punch roller, 501: first roller cutter, 502: second roller cutter.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/044086 | 11/11/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/095087 | 5/20/2021 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20070084589 | Nishino et al. | Apr 2007 | A1 |
| 20170082381 | Sugimura et al. | Mar 2017 | A1 |
| 20200103418 | Matsumoto et al. | Apr 2020 | A1 |
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| 3015808 | May 2016 | EP |
| 3173725 | May 2017 | EP |
| 59-94270 | Jun 1984 | JP |
| 2007113802 | May 2007 | JP |
| 2015-183908 | Oct 2015 | JP |
| WO-2014207785 | Dec 2014 | WO |
| WO-2016013100 | Jan 2016 | WO |
| WO-2017154175 | Sep 2017 | WO |
| 2018154806 | Aug 2018 | WO |
| Entry |
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| International Search Report and Written Opinion mailed on Dec. 10, 2019, received for PCT Application PCT/JP2019/044086, Filed on Nov. 11, 2019, 10 pages including English Translation. |
| Extended European Search Report issued Oct. 10, 2022 in corresponding European Patent Application No. 19952231.9, 6 pages. |
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| Number | Date | Country | |
|---|---|---|---|
| 20240085122 A1 | Mar 2024 | US |
