This application is a U.S. national stage application of International Application No. PCT/JP2018/026186 filed on Jul. 11, 2018, the contents of which are incorporated herein by reference.
The present disclosure relates to a heat exchanger, a heat exchanger unit including the heat exchanger, and a refrigeration cycle apparatus, and, in particular, to a structure of a fin attached to a heat transfer tube.
There have been known heat exchangers including flat tubes that are heat transfer tubes whose sections each have a flat shape and a plurality of holes to improve heat exchange performance. Such a heat exchanger in which a plurality of flat tubes are arranged in parallel with each other such that their longitudinal tube axes are along the direction of gravity includes a header that distributes or collects fluid to be subjected to heat exchange at lower end portions in the direction of gravity of the flat tubes. In such a heat exchanger, frost melt water on surfaces of the flat tubes or fins is discharged in the direction of gravity along the flat tubes or the fins. For this reason, water easily remains on an upper surface of the header, in particular, joints between the header and the flat tubes, and easily remains between the upper surface of the header and the fins. There has been known a heat exchanger in which an upper surface of a header is inclined in the direction of gravity to facilitate discharge of frost melt water from the upper surface of the header (for example, see Patent Literature 1).
Patent Literature 1: International Publication No. 2015/189990
However, in the existing heat exchanger described in Patent Literature 1, water easily remains on joints between flat tubes and the header, and in a space between fins and the header due to surface tension. In particular, the water remaining on the upper surface of the header freezes under conditions in which the heat exchanger is exposed to low-temperature air. Thus, there is a problem in that discharge of the water reaching the upper surface of the header from an upper portion of the heat exchanger is obstructed and this causes a frozen part to be further expanded. The expansion of the frozen part causes problems in the heat exchanger in that the heat exchange performance is impaired and the reliability is reduced due to damage of the flat tubes, the fins, or a header tank.
The heat exchanger of the present disclosure is made to overcome such problems, and aims to provide a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus in which frost melt water is inhibited from reaching an upper surface of a header and the heat exchange performance and the reliability are improved.
A heat exchanger according to an embodiment of the present disclosure includes: a plurality of heat transfer tubes arranged in parallel with each other; a fin connected to at least one of the plurality of heat transfer tubes; a header having a header end surface being a surface along a direction in which the plurality of heat transfer tubes are arranged in parallel with each other, the header being connected to one end portions of the plurality of heat transfer tubes, the fin having a first portion including an edge facing the header and a second portion other than the first portion, the fin extending in a first direction crossing the direction in which the plurality of heat transfer tubes are arranged in parallel with each other, the first direction being perpendicular to a tube axis of each of the plurality of heat transfer tubes, wherein an end portion in the first direction of the first portion projects in the first direction relative to the header end surface, and an end portion in the first direction of the second portion is positioned closer in the first direction to the plurality of heat transfer tubes than the header end surface is to the plurality of heat transfer tubes.
A heat exchanger unit according to another embodiment of the present disclosure includes the heat exchanger.
A refrigeration cycle apparatus according to still another embodiment of the present disclosure includes the heat exchanger unit.
According to an embodiment of the present disclosure, the heat exchanger can be improved in both heat exchange performance and reliability by reducing the amount of water flowing onto an upper surface of the header and by inhibiting a frozen part of the upper surface of the header from expanding.
Embodiments of a heat exchanger and a heat exchanger unit are described below. The forms in the drawings are examples, and the present disclosure is not limited thereby. In the drawings, components having the same reference signs are the same or corresponding components, and this applies to the entire description. In addition, the size relationships of the components in the drawings below may differ from those of actual ones.
The outdoor heat exchanger 5 accommodated in an outdoor unit 8 and the indoor heat exchanger 7 accommodated in an indoor unit 9 are provided with respective fans 2 near the outdoor heat exchanger 5 and the indoor heat exchanger 7. The fan 2 in the outdoor unit 8 sends the outside air into the outdoor heat exchanger 5, and the outdoor heat exchanger 5 exchanges heat between the outside air and refrigerant. The fan 2 in the indoor unit 9 sends indoor air into the indoor heat exchanger 7, and the indoor heat exchanger 7 exchanges heat between the indoor air and refrigerant and conditions indoor air temperature. The heat exchanger 100 can be used as the outdoor heat exchanger 5 accommodated in the outdoor unit 8 and the indoor heat exchanger 7 accommodated in the indoor unit 9 in the refrigeration cycle apparatus 1. The heat exchanger 100 functions as a condenser or an evaporator. Devices such as the outdoor unit 8 and the indoor unit 9, in which the heat exchanger 100 is accommodated, are specifically referred to as heat exchanger units.
The heat exchanger 100 illustrated in
The heat transfer tubes 21 each have a flat shape and a section perpendicular to the longitudinal tube axis having a major axis and a minor axis. A plurality of refrigerant passages 22, through which refrigerant flows, are disposed in each of the heat transfer tubes 21. The refrigerant passages 22 are arranged from one end portion 23 of the major axis of each of the heat transfer tubes 21 toward the other end portion 24. The heat transfer tubes 21 are made of metal material having thermal conductivity. For example, aluminum, aluminum alloy, copper, or copper alloy is used as the material for forming the heat transfer tubes 21. The heat transfer tubes 21 are produced by an extrusion process in which the section illustrated in
Fins 30 and 40 are connected the respective heat transfer tubes 21. Each of the fins 30 extends in the x direction from the one end portion 23 of the major axis of the corresponding heat transfer tube 21, which is a flat tube. That is, each of the fins 30 extends in the direction that is perpendicular to the longitudinal tube axis of each of the heat transfer tubes 21 and that crosses the direction in which the heat transfer tubes 21 are arranged in parallel with each other. In the description, the direction in which the fins 30 extend from the end portions 23 of the heat transfer tubes 21 is referred to as the first direction D. In Embodiment 1, each of the fins 30 extends along the major axis of a section of the corresponding heat transfer tube 21, which is a flat tube. Each of the fins 40 extends, from the other end portion 24 of the corresponding heat transfer tube 21, which is a flat tube, in the direction opposite to the direction in which the fins 30 extend. The directions in which the fins 30 and 40 extend are not limited only to the x direction illustrated in
As illustrated in
In Embodiment 1, a heat transfer tube unit 20 is composed of the heat transfer tube 21 and the fins 30 and 40 (plate-like part 80). As illustrated in
As illustrated in
The heat exchanger 100 according to Embodiment 1 is disposed such that the end edges 32 of the fins 30 face windward. As illustrated in
Effects of the heat exchanger 100 according to Embodiment 1 are described. To make a drainage-facilitating effect of the heat exchanger 100 according to Embodiment 1 easy to understand, operation of the heat exchanger 100 functioning as an evaporator under a low-temperature outside air condition is described below. Subsequently, the configuration of a heat exchanger 1100 in a comparative example is described, and the drainage-facilitating effect of the heat exchanger 100 according to Embodiment 1 is then described.
In the description of the comparative example, each of the components in the comparative example is assigned a reference numeral that is determined by adding 1000 to the value of a reference numeral of a corresponding one of the components in Embodiment 1. For example, the heat exchanger in the comparative example is represented as the heat exchanger 1100. In the description of the heat exchanger 1100 in the comparative example, the components that are the same as those of the heat exchanger 100 according to Embodiment 1 have the same reference signs.
When the refrigeration cycle apparatus 1 operates and the heat exchanger 100 functions as an evaporator, low-temperature refrigerant flows through the refrigerant passages 22 of the heat transfer tubes 21. When the refrigerant temperature is 0 degrees C. or less, the moisture in the air sent into the heat exchanger 100 changes into frost on surfaces of the heat transfer tube units 20, and the frost adheres to the surfaces of the heat transfer tube units 20. In this case, the refrigeration cycle apparatus 1 typically performs the defrosting operation after a normal operation, and the frost adhering to the surfaces of the heat transfer tube units 20 is removed. The defrosting operation is an operation in which high-temperature refrigerant flows through the refrigerant passages 22 to melt the frost adhering to the heat transfer tube units 20. As a result of this operation, frost melt water is generated on the surfaces of the heat transfer tube units 20.
On the other hand, in the heat exchanger 100 according to Embodiment 1, on the windward side, on which frost is intensively generated, the end 31 closer to the lower end header 50 of the fin 30 projects to the windward relative to the header end surface 51 of the lower end header 50. In other words, the end portion of the part including the edge 34 facing the header of the fin 30 projects in the x direction relative to the header end surface 51. The part including the edge 34 facing the header of the fin 30 is specifically referred to as the first portion. Since the end portion of the first portion projects in the x direction relative to the header end surface 51, as illustrated in
As illustrated in
As illustrated in
For example, when the heat exchanger 100b is disposed in a heat exchanger unit, and the fan 2 configured to send air into the heat exchanger 100b is a propeller fan, the amount of projection, from the heat transfer tube 21, of parts of the fin 30b where the flow velocity of air passing through the heat exchanger 100b is high is set to be large. On the other hand, the amount of projection, from the heat transfer tube 21, of parts of the fin 30b where the flow velocity of air passing through the heat exchanger 100b is low is set to be relatively small. The parts of the fin 30b whose amount of projection from the heat transfer tube 21 is large have lower conductivity of cooling energy from the heat transfer tube 21 than that of the parts of the fin 30b whose amount of projection from the heat transfer tube 21 is small. For this reason, the amount of frost generated on the end edge 32 of the fin 30b can be reduced. Thus, the amount of frost generated on the fin 30b can be controlled by increasing the amount of projection, from the heat transfer tube 21, of the parts of the fin 30b where the amount of air sent into the heat exchanger 100b is large, that is, the parts of the fin 30b where the flow velocity of air passing through the heat exchanger 100b is high.
As illustrated in
The shapes of the fins 30 and 30a to 30c of the heat exchangers 100 and 100a to 100c are not limited to the shapes illustrated in
As illustrated in
In Embodiment 1, although the heat transfer tubes 21 are flat tubes, the heat transfer tubes 21 may be heat transfer tubes whose sections each have a round shape. However, when the heat transfer tubes 21 are flat tubes, it is advantageous to employ configurations such as those of the heat exchangers 100 and 100a to 100d according to Embodiment 1 because the longitudinal tube axis of each of the heat transfer tubes 21 is often along the direction of gravity to facilitate downward flow of the water adhering to surfaces of the flat tubes.
The fins 30 are made of a plate-like metal material having thermal conductivity. For example, aluminum, aluminum alloy, copper, or copper alloy is used as the material for forming the fins 30.
In a heat exchanger 200 according to Embodiment 2, the direction in which the fin 30 projects relative to the lower end header 50 is changed from that in the heat exchanger 100 according to Embodiment 1. In other words, the positional relationship between the heat exchanger 100 and the fan 2 in a heat exchanger unit is reversed with that in Embodiment 1. The heat exchanger 200 according to Embodiment 2 is described with the focus on the differences between Embodiment 1 and Embodiment 2. The parts of the heat exchanger 200 according to Embodiment 2 having the same functions in the drawings are represented to have the same reference signs as those in the drawings used in the description of Embodiment 1.
Water guides 270, such as grooves and projections or a louver, are formed on surfaces of the fins 230 and 240 of the heat exchanger 200. Preferably, the water guides 270 are formed such that their edge lines are along the x direction, or are formed to be inclined, in the direction of gravity, from the fin 240 on the windward side toward the fin 240 on the leeward side.
In the heat exchanger 200 according to Embodiment 2, when the heat exchanger 200 operates as an evaporator, the frost melt water intensively generated on the windward side of the fin 230 is moved along the water guides 270 and is guided toward an end edge 242 of the fin 240 by the air sent by the fan 2. The water guides 270 are each formed along the x direction and are arranged on the heat transfer tube 21 in the y direction. The water guides 270 are each disposed with a space between an end portion thereof and the end edge 242. For this reason, frost melt water is moved toward the fin 240 by airflow. The frost melt water reaching the vicinity of the end edge 242 of the fin 240 flows down along the end edge 242 and is then discharged below the edge 244 facing the header. Thus, the frost melt water adhering to the fins 230 and 240 is discharged to the outside of the heat exchanger 200 without reaching the upper surface 53 of the lower end header 50. In the heat exchanger 200 according to Embodiment 2, in addition to frost melt water, the condensed water generated on the entire fins 230 and 240 can be discharged toward the leeward side. As a result, it is possible to inhibit freezing of the upper surface 53 of the lower end header 50 from progressing and a frozen part of the upper surface 53 of the lower end header 50 from expanding. Accordingly, it is possible to reduce impairment of the heat exchange performance and to improve the reliability.
In a heat exchanger 300 according to Embodiment 3, the shape of a lower end portion of the fin 30 is changed from that in the heat exchanger 100 according to Embodiment 1. The heat exchanger 300 according to Embodiment 3 is described with the focus on the differences between Embodiment 1 and Embodiment 3. The parts of the heat exchanger 300 according to Embodiment 3 having the same functions in the drawings are represented to have the same reference signs as those in the drawings used in the description of Embodiment 1.
The heat exchanger 300 is formed as described above, and thus the water remaining on the boundary portion between the heat transfer tube 21 and the upper surface of the lower end header 50 and remaining in a space between the fin 330 and the upper surface of the lower end header 50 moves along the edge 334 facing the header and then drops from the end 331. The edge 334 facing the header is inclined, toward the end 331 from a part closer to the heat transfer tube 21 of the edge 334, downward from above the upper surface 53 of the lower end header 50. The water remaining on the upper surface 53 flows along the slant of the edge 334 facing the header due to capillary action. Thus, the water moving along the heat transfer tube 21 and the fin 330 and then remaining on the upper surface 53 of the lower end header 50 is efficiently discharged. As a result, it is possible to inhibit freezing of the upper surface 53 of the lower end header 50 from progressing and a frozen part of the upper surface 53 of the lower end header 50 from expanding. Accordingly, it is possible to reduce impairment of the heat exchange performance and to improve the reliability.
In Embodiment 3, although the edge 334 facing the header of the fin 330 is inclined downward in a straight line from the part closer to the heat transfer tube 21 of the edge 334, the edge 334 may have other shapes as long as the end 331 is positioned below the upper surface 53 of the lower end header 50. For example, the edge 334 facing the header may be formed by an arc and can be modified as appropriate according to, for example, the shape of the lower end header 50.
In a heat exchanger 400 according to Embodiment 4, the fin is changed from the fin 30 in the heat exchanger 100 according to Embodiment 1 into a corrugated fin. The heat exchanger 400 according to Embodiment 4 is described with the focus on the differences between Embodiment 1 and Embodiment 4. The parts of the heat exchanger 400 according to Embodiment 4 having the same functions in the drawings are represented to have the same reference signs as those in the drawings used in the description of Embodiment 1.
The configuration of the corrugated fin 430 is similar to the configuration of the heat exchanger 100 according to Embodiment 1 in that a part including an edge 434 facing the header of the corrugated fin 430 projects relative to the header end surface 51 of the lower end header 50. A wavy part of the corrugated fin 430 is arranged in the y direction and is formed such that the air sent into the heat exchanger 400 passes through spaces in the wavy part of the corrugated fin 430. In addition, the corrugated fin 430 is formed such that air passes between the heat transfer tubes 21. That is, parts at the same phases of the wavy part of the corrugated fin 430 are disposed along the x direction. From the perspective illustrated in
The corrugated fin 430 is disposed between the two heat transfer tubes 21. An end edge 432 of the corrugated fin 430 projects in the x direction relative to the one end portion 23 of the major axis of the heat transfer tube 21. A first portion that is a part of the corrugated fin 430 and that includes the edge 434 facing the lower end header 50 of the corrugated fin 430 projects in the x direction relative to the header end surface 51. An end 431 of the edge 434 facing the header projects in the x direction relative to the header end surface 51. The lower end header 50 does not exist under the end 431. The end 431, which is positioned closer to the lower end header 50, of the end edge 432 of the corrugated fin 430 projects in the x direction relative to the header end surface 51, which is one end surface of the lower end header 50. An end 433, which is positioned closer to the upper end header 60, of the end edge 432 is positioned closer to the heat transfer tube 21 than the header end surface 51, which is one end surface of the lower end header 50, is. The end edge 432 is formed by a straight line inclined relative to the longitudinal tube axis of the heat transfer tube 21 from the end 433 closer to the upper end header 60 toward the end 431 closer to the lower end header 50.
The end edges 432 and 432a of the corrugated fins 430 and 430a can be shaped like, for example, the end edges 32a to 32c of the fins 30a to 30c in Embodiment 1. In addition, similarly to Embodiment 2, the end edges 432 and 432a of the corrugated fins 430 and 430a may face leeward.
The corrugated fin 430 is disposed in the heat exchangers 400 and 400a according to Embodiment 4, and thus the heat exchangers 400 and 400a according to Embodiment 4 have the advantage of high heat exchange performance. In addition, frost melt water and condensed water move downward and are discharged from the end 431 of the lower end header 50 of the corrugated fin 430. As a result, similarly to Embodiment 1 to Embodiment 3, in the heat exchangers 400 and 400a, it is possible to inhibit freezing of the upper surface 53 of the lower end header 50 from progressing and a frozen part of the upper surface 53 of the lower end header 50 from expanding. Accordingly, it is possible to reduce impairment of the heat exchange performance and to improve the reliability.
In addition, when the wavy part of the corrugated fin 430a is disposed to be inclined as in the case of the heat exchanger 400a, the water adhering to the corrugated fin 430a easily moves toward the end edge 432. The water that has moved to the end edge 432 moves along the end edge 432a, reaches the end 431a, and is then discharged downward. Thus, it is possible to discharge water more efficiently. In addition, the end 431a is positioned below the upper surface 53 of the lower end header 50. Thus, the end 431a is formed such that the water remaining on the upper surface 53 also moves along an edge 434a facing the header due to capillary action and is easily discharged.
1 refrigeration cycle apparatus 2 fan 3 compressor 4 four-way valve outdoor heat exchanger 6 expansion device 7 indoor heat exchanger 8 outdoor unit 9 indoor unit 10 heat exchange unit 20 heat transfer tube unit heat transfer tube 22 refrigerant passage 23 end portion 24 end portion 30 fin 30a fin 30b fin 30c fin 31 end 31a end 31b end 31c end 32 end edge 32a end edge 32b end edge 32c end edge 33 end 33b end 34 edge line facing header 35b center 40 fin 50 lower end header 51 header end surface 52 header end surface 53 upper surface 60 upper end header 70 water guide 80 plate-like part 90 refrigerant pipe 100 heat exchanger 100a heat exchanger 100b heat exchanger 100c heat exchanger 100d heat exchanger 200 heat exchanger 230 fin 240 fin 241 end 242 end edge 244 edge facing header 270 water guide 300 heat exchanger 300a heat exchanger 330 fin 331 end 334 edge facing header 400 heat exchanger 400a heat exchanger 430 corrugated fin 430a corrugated fin 431 end 431a end 432 end edge 432a end edge 433 end 434 edge facing header 434a edge facing header 436 ridge 436a ridge 437 recess 437a recess 1030 fin 1032 end edge 1100 heat exchanger A section B arrow C arrow D first direction
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/026186 | 7/11/2018 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/012577 | 1/16/2020 | WO | A |
Number | Name | Date | Kind |
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20130206376 | Shikazono | Aug 2013 | A1 |
20180100659 | Yoshimura et al. | Apr 2018 | A1 |
20190033017 | Abastari | Jan 2019 | A1 |
Number | Date | Country |
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107407534 | Nov 2017 | CN |
2980516 | Feb 2016 | EP |
3156752 | Apr 2017 | EP |
2016-170601 | Sep 2016 | JP |
2014155560 | Oct 2014 | WO |
2015189990 | Dec 2015 | WO |
2017017789 | Feb 2017 | WO |
WO-2017017789 | Feb 2017 | WO |
2017168669 | Oct 2017 | WO |
Entry |
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Pdf file is translation of foreign reference WO 2017017789 A1 (Year: 2017). |
Attached pdf is translation of foreign reference WO 2017017789 (Year: 2017). |
International Search Report of the International Searching Authority dated Oct. 2, 2018 for the corresponding International application No. PCT/JP2018/026186 (and English translation). |
Examination Report dated Apr. 30, 2021, issued in corresponding IN Patent Application No. 202027051832 (and English Machine Translation). |
Number | Date | Country | |
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20210108864 A1 | Apr 2021 | US |