WO2023218629A1

WO2023218629A1 - Heat exchanger

Info

Publication number: WO2023218629A1
Application number: PCT/JP2022/020172
Authority: WO
Inventors: 篤史 ▲高▼橋; 剛志前田; 悟梁池; 伸中村; 敦森田
Original assignee: 三菱電機株式会社
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2023-11-16

Abstract

This heat exchanger comprises: a plurality of flat tube groups each composed of a plurality of flat tubes which face each other so as to be parallel to each other on flat surfaces thereof and through which a refrigerant flows in the same direction, with a vertical direction set as a tube extending direction; a bypass piping which is disposed between adjacent flat tube groups and through which the refrigerant flows in a direction opposite to that of the adjacent flat tube groups; an upper header which is disposed above the flat tube groups and the bypass piping, and into which ends of those are inserted; and a lower header which is disposed below the flat tube groups and the bypass piping, and into which ends of those are inserted. When functioning as a condenser, the heat exchanger is configured such that the refrigerant inside the flat tube groups flows downward while the refrigerant inside the bypass piping flows upward. Inside the respective upper and lower headers, the ends of the bypass piping are disposed below the ends of the respective flat tubes.

Description

Heat exchanger

The present disclosure relates to a heat exchanger including a plurality of flat tubes.

Conventionally, an air heat exchanger equipped with a plurality of flat tubes has been adopted, for example, as a heat exchanger for an air conditioner. In this air conditioner, liquid refrigerant condensed by a heat exchanger that functions as a condenser mounted on an indoor unit is depressurized by a throttle device. Then, the refrigerant becomes a gas-liquid two-phase state in which gas refrigerant and liquid refrigerant are mixed, and flows into a heat exchanger that functions as an evaporator mounted on the outdoor unit.

In a heat exchanger equipped with a plurality of flat tubes, in order to reduce pressure loss, the number of flat tubes becomes enormous, making it difficult to uniformly distribute refrigerant to each flat tube. Therefore, in order to equalize the refrigerant distribution when the heat exchanger functions as an evaporator, we used a configuration in which the header extends horizontally, which makes it difficult for gas-liquid separation to occur due to gravity. It is being said. However, in this configuration, when the heat exchanger functions as a condenser, the refrigerant is significantly distributed in the upward flow part of the flat tube due to the increase in liquid head due to the phase change in the flat tube extending in the vertical direction. The problem is that the performance deteriorates and the heat exchanger performance deteriorates.

Therefore, if the header is extended horizontally and the header is divided longitudinally, and the heat exchanger functions as a condenser, the refrigerant flows downward in the flat tubes, and the refrigerant flows upward in the bypass tubes. has been proposed (for example, see Patent Document 1). As in the configuration of Patent Document 1, by dividing the header into shorter lengths and reducing the portion where the refrigerant flows upward, the deterioration of the distribution performance in the longitudinal direction of the header is suppressed, and the deterioration of the heat exchanger performance is suppressed. is suppressed. Furthermore, by allowing the refrigerant to flow downward in the flat tube, the liquefied refrigerant can flow in the direction of gravity, improving the heat transfer coefficient of the refrigerant and improving the heat exchanger performance.

Japanese Patent Application Publication No. 2001-141382

However, in Patent Document 1, since the header extends in the horizontal direction, the liquid refrigerant stays at the bottom of the header, and depending on the positions of the end faces of the bypass pipe and the flat tube, the liquid refrigerant that stays at the bottom of the header may cause the liquid refrigerant to flow into the flat tube. There was a problem in that there were areas where it was difficult for the refrigerant to flow, resulting in a decrease in heat exchanger performance.

The present disclosure has been made to solve the above problems, and when functioning as a condenser, it suppresses the accumulation of liquid refrigerant in the header and uniformizes the distribution of the refrigerant, thereby improving heat exchange. The purpose is to provide a heat exchanger with improved heat exchanger performance.

The heat exchanger according to the present disclosure includes a plurality of flat tubes in which a refrigerant flows in the same direction, the tubes extending in the vertical direction, and having flat surfaces facing each other so as to be parallel to each other. a bypass pipe arranged between the adjacent flat tube groups and through which a refrigerant flows in the opposite direction to the adjacent flat tube groups; and a bypass pipe arranged above the plurality of flat tube groups and the bypass pipe. and a lower header arranged below the plurality of flat tube groups and the bypass piping and into which the ends thereof are inserted, and functions as a condenser. In this case, the refrigerant flows downward inside the plurality of flat tube groups, and the refrigerant flows upward inside the bypass piping. The ends of the bypass piping are arranged below the ends of each of the flat tubes.

According to the heat exchanger according to the present disclosure, when functioning as a condenser, the refrigerant is configured to flow downward inside the plurality of flat tube groups and to flow upward inside the bypass piping, Inside each of the upper header and the lower header, the end of the bypass piping is located below the end of each flat tube. Therefore, when the heat exchanger functions as a condenser, the liquid refrigerant that has accumulated on the bottom surface of the lower header can be raised by the bypass piping. As a result, the occurrence of areas in the flat tube where it is difficult for the refrigerant to flow is suppressed, and the distribution of the refrigerant in the flat tube where the internal refrigerant flows downward can be made uniform, thereby improving the heat exchanger performance. Moreover, since the liquid refrigerant that has accumulated on the bottom surface of the upper header is mixed with the refrigerant flowing out from the bypass pipe, liquid accumulation is suppressed.

FIG. 2 is a schematic diagram showing the flow of refrigerant when the heat exchanger according to Embodiment 1 functions as a condenser. FIG. 3 is a schematic diagram showing the flow of refrigerant when the heat exchanger according to the first embodiment functions as an evaporator. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a modification of the first embodiment functions as an evaporator. FIG. 7 is a schematic diagram showing the flow of refrigerant when the heat exchanger according to Embodiment 2 functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a first modification of the second embodiment functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a second modification of the second embodiment functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a third modification of the second embodiment functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a fourth modification of the second embodiment functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when a heat exchanger according to a fifth modification of the second embodiment functions as a condenser. FIG. 7 is a schematic diagram showing the flow of refrigerant when the heat exchanger according to Embodiment 3 functions as a condenser.

Hereinafter, embodiments of the present disclosure will be described based on the drawings. Note that the present disclosure is not limited to the embodiments described below. Further, in the following drawings, the size relationship of each component may differ from the actual one.

Embodiment 1.
FIG. 1 is a schematic diagram showing the flow of refrigerant when heat exchanger 100 according to Embodiment 1 functions as a condenser. FIG. 2 is a schematic diagram showing the flow of refrigerant when heat exchanger 100 according to the first embodiment functions as an evaporator. Note that the arrows in FIGS. 1 and 2 indicate the flow of the refrigerant, and the same applies to the drawings described later.

As shown in FIGS. 1 and 2, in the heat exchanger 100 according to the first embodiment, a pair of distribution headers consisting of an upper header 10 and a lower header 20 are arranged vertically separated in the height direction. .

Between the pair of distribution headers, a plurality of flat tubes 31 are arranged, with the vertical direction being the tube extending direction and flat surfaces facing each other so as to be parallel to each other, and through which the refrigerant flows in the same direction. Two flat tube groups 30 are arranged. That is, the plurality of flat tubes 31 are arranged at intervals in the horizontal direction orthogonal to the vertical direction. The flat tube 31 has a flat cross section, and the outer surface on the longitudinal side of the flat shape along the air flow direction (direction perpendicular to the plane of the paper in FIGS. 1 and 2) is planar, and the flat tube 31 has a flat cross section. This is a heat exchanger tube whose outer surface on the shorter side is curved. The flat tube 31 according to Embodiment 1 is a multi-hole flat tube that has a plurality of holes that serve as refrigerant flow paths inside the tube. In the first embodiment, the holes in the flat tube 31 are formed along the height direction to serve as flow paths between the pair of distribution headers. Note that the number of flat tubes 31 constituting each flat tube group 30 is an arbitrary number.

A bypass pipe 40 is provided between the two adjacent flat tube groups 30, through which the refrigerant flows in the opposite direction to the two adjacent flat tube groups 30. That is, the heat exchanger 100 has two flat tube groups 30 and one bypass pipe 40. Here, the passage cross-sectional area of one bypass pipe 40 is larger than the passage cross-sectional area of one flat pipe 31. By doing so, the pressure loss of the refrigerant when the heat exchanger 100 functions as an evaporator can be suppressed, and the performance of the heat exchanger can be improved. Further, due to unevenness in the wind speed distribution passing through the heat exchanger 100, variations in the state of the refrigerant due to differences in the amount of heat exchanged between the respective flat tubes 31 can be eliminated by merging them in the bypass pipe 40, The refrigerant can be uniformly distributed to the next flat tube group 30, and the heat exchanger performance can be improved.

An upper header 10 is provided above the flat tube group 30 and the bypass piping 40, and the upper ends of the flat tubes 31 of the flat tube group 30 and the bypass piping 40 are inserted into the upper header 10. At this time, inside the upper header 10, the upper end of the bypass pipe 40 (see hu2 in FIG. 1) is arranged below the upper end of each flat tube 31 of the flat tube group 30 (see hu1 in FIG. 1). ing. Further, a lower header 20 is provided below the flat tube group 30 and the bypass piping 40, and the lower ends of the flat tubes 31 of the flat tube group 30 and the bypass piping 40 are inserted into the lower header 20. . At this time, inside the lower header 20, the lower end of the bypass pipe 40 (see hl2 in FIG. 1) is arranged below the lower end of each flat tube 31 of the flat tube group 30 (see hl1 in FIG. 1). ing. That is, in the upper header 10, the insertion amount of the bypass piping 40 is smaller than the insertion amount of the flat tubes 31 in the flat tube group 30, and in the lower header 20, the insertion amount of the bypass piping 40 is smaller than the insertion amount in the flat tube group 30. The amount of insertion of the flat tube 31 is greater than the amount of insertion of the flat tube 31.

The upper header 10 has a refrigerant flow path formed inside. Furthermore, a first partition 11 is provided inside the upper header 10 to partition a refrigerant flow path. Furthermore, a refrigerant inlet/outlet 51 is formed at one end of the upper header 10 . The lower header 20 has a refrigerant flow path formed therein. Further, a second partition 21 is provided inside the lower header 20 to partition a refrigerant flow path. Further, a refrigerant inlet/outlet 52 is formed at one end of the lower header 20 located on the opposite side from one end of the upper header 10 .

The first partition 11 is arranged between the upper end of the flat tube group 30 and the upper end of the bypass piping 40. Further, the second partition 21 is arranged between the lower end of the flat tube group 30 and the lower end of the bypass piping 40.

As shown in FIG. 1, when the heat exchanger 100 functions as a condenser, high-temperature, high-pressure gas refrigerant flows into the upper header 10 from the refrigerant inlet/outlet 51. The gas refrigerant that has flowed into the upper header 10 flows downward inside each flat tube 31 of the upstream flat tube group 30 and joins at the lower header 20 . The refrigerants that have merged at the lower header 20 flow upward inside the bypass pipe 40 and merge at the upper header 10. The refrigerant that has merged at the upper header 10 flows downward inside each flat tube 31 of the flat tube group 30 on the downstream side, merges at the lower header 20, and then flows out from the refrigerant inlet/outlet port 52. The high-temperature, high-pressure gas refrigerant that has flowed into the heat exchanger 100 exchanges heat with air while flowing through the flat tubes 31 and bypass piping 40, and flows out of the heat exchanger 100 as a low-temperature, high-pressure liquid refrigerant. That is, when the heat exchanger 100 functions as a condenser, the refrigerant inlet/outlet 51 becomes a gas refrigerant inlet, and the refrigerant inlet/outlet 52 becomes a liquid refrigerant outlet.

As shown in FIG. 2, when the heat exchanger 100 functions as an evaporator, low-temperature, low-pressure two-phase refrigerant flows into the lower header 20 from the refrigerant inlet/outlet 52. The two-phase refrigerant that has flowed into the lower header 20 flows upward inside each flat tube 31 of the upstream flat tube group 30 and joins at the upper header 10 . The refrigerants that have merged at the upper header 10 flow downward inside the bypass pipe 40 and merge at the lower header 20. The refrigerant that has merged at the lower header 20 flows upward inside each flat tube 31 of the flat tube group 30 on the downstream side, merges at the upper header 10, and then flows out from the refrigerant inlet/outlet port 51. Note that the low-temperature, low-pressure two-phase refrigerant that has flowed into the heat exchanger 100 exchanges heat with air while flowing through the flat tubes 31 and the bypass piping 40, and flows out of the heat exchanger 100 as a high-temperature, low-pressure gas refrigerant. That is, when the heat exchanger 100 functions as an evaporator, the refrigerant inlet/outlet 52 becomes a two-phase refrigerant inlet, and the refrigerant inlet/outlet 51 becomes a gas refrigerant outlet.

As described above, when the heat exchanger 100 functions as a condenser, it is configured so that the refrigerant flows downward inside the two flat tube groups 30 and flows upward inside the bypass piping 40. . Further, when the heat exchanger 100 functions as an evaporator, the refrigerant is configured to flow upward within the two flat tube groups 30 and flow downward within the bypass piping 40. In other words, the refrigerant flows through the two flat tube groups 30 and the bypass piping 40 in opposite directions.

The effects when the heat exchanger 100 functions as a condenser include the following. In the lower header 20, the lower end of the bypass piping 40 is arranged below the lower end of each flat tube 31 of the flat tube group 30, so that the liquid refrigerant accumulated on the bottom surface of the lower header 20 is removed by the bypass piping 40. It is possible to suck it up and raise it. As a result, the occurrence of regions in the flat tubes 31 where it is difficult for the refrigerant to flow is suppressed, and the distribution of the refrigerant in the flat tubes 31, where the internal refrigerant flows downward, can be made uniform, improving heat exchanger performance. do. Furthermore, in the upper header 10, the upper end of the bypass piping 40 is disposed below the upper end of each flat tube 31 of the flat tube group 30, so that the liquid refrigerant that has accumulated on the bottom surface of the upper header 10 can be bypassed. Since the refrigerant is mixed by the refrigerant flowing out from the pipe 40, liquid retention is suppressed.

Effects when the heat exchanger 100 functions as an evaporator include the following. In the upper header 10 , the upper end of the bypass piping 40 is arranged below the upper end of each flat tube 31 of the flat tube group 30 , so the liquid refrigerant that stays on the bottom surface of the upper header 10 flows through the bypass piping 40 . The liquid reaches the upper end, and liquid retention near the flat tube 31 is suppressed. As a result, it is possible to reduce the amount of liquid refrigerant that has accumulated on the bottom surface of the upper header 10, and it is possible to suppress a decrease in the defrosting heat amount due to the low-temperature liquid refrigerant that has accumulated in the upper header 10 during defrosting.

FIG. 3 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100a according to a modification of the first embodiment functions as an evaporator. In the first embodiment, two flat tube groups 30 are arranged between a pair of distribution headers, but the present invention is not limited to this, and three or more flat tube groups 30 are arranged between a pair of distribution headers. may be placed. For example, like the heat exchanger 100a shown in FIG. 3, four flat tube groups 30 may be arranged between a pair of distribution headers. In this case, bypass piping 40 through which the refrigerant flows in the opposite direction to the two adjacent flat tube groups 30 is provided between each of the two adjacent flat tube groups 30 . That is, the heat exchanger 100a has four flat tube groups 30 and three bypass pipes 40.

The upper header 10 has a refrigerant flow path formed inside. Further, inside the upper header 10, a plurality of first partitions 11 are provided to partition a refrigerant flow path. Furthermore, a refrigerant inlet/outlet 51 is formed at one end of the upper header 10 . The lower header 20 has a refrigerant flow path formed therein. Further, inside the lower header 20, a plurality of second partitions 21 are provided to partition a refrigerant flow path. Further, a refrigerant inlet/outlet 52 is formed at one end of the lower header 20 located on the opposite side from one end of the upper header 10 .

As described above, the heat exchanger 100 according to Embodiment 1 is composed of a plurality of flat tubes 31 in which the tube extending direction is the vertical direction and the flat surfaces thereof are opposed so as to be parallel to each other, and through which the refrigerant flows in the same direction. a plurality of flat tube groups 30 , a bypass pipe 40 that is arranged between adjacent flat tube groups 30 and through which refrigerant flows in the opposite direction to the adjacent flat tube groups 30 , and a plurality of flat tube groups 30 and An upper header 10 that is arranged above the bypass piping 40 and has its ends inserted therein, and a lower header 20 that is arranged below the plurality of flat tube groups 30 and the bypass piping 40 and has its ends inserted therein. When functioning as a condenser, the refrigerant flows downward inside the plurality of flat tube groups 30 and flows upward inside the bypass piping 40. Inside each of the lower headers 20, the ends of the bypass piping 40 are arranged below the ends of each flat tube 31.

According to the heat exchanger 100 according to the first embodiment, when functioning as a condenser, the refrigerant flows downward inside the plurality of flat tube groups 30 and flows upward inside the bypass piping 40. In each of the upper header 10 and the lower header 20, the end of the bypass piping 40 is arranged below the end of each flat tube 31. Therefore, when the heat exchanger 100 functions as a condenser, the liquid refrigerant stagnant on the bottom surface of the lower header 20 can be raised by the bypass pipe 40. As a result, the occurrence of regions in the flat tubes 31 where it is difficult for the refrigerant to flow is suppressed, and the distribution of the refrigerant in the flat tubes 31, where the internal refrigerant flows downward, can be made uniform, improving heat exchanger performance. do. Moreover, since the liquid refrigerant that has accumulated on the bottom surface of the upper header 10 is mixed with the refrigerant that flows out from the bypass pipe 40, liquid accumulation is suppressed.

Furthermore, in the heat exchanger 100 according to the first embodiment, the passage cross-sectional area of the bypass pipe 40 is larger than the passage cross-sectional area of the flat tube 31.

According to the heat exchanger 100 according to the first embodiment, the pressure loss of the refrigerant when the heat exchanger 100 functions as an evaporator can be suppressed, and the heat exchanger performance can be improved.

Embodiment 2.
Embodiment 2 will be described below, but the description of parts that overlap with Embodiment 1 will be omitted, and the same or corresponding parts as in Embodiment 1 will be given the same reference numerals.

FIG. 4 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100b according to the second embodiment functions as a condenser.

In the heat exchanger 100b according to the second embodiment, when a module M is a combination of two flat tube groups 30 and a bypass pipe 40 arranged between two mutually adjacent flat tube groups 30, the condenser A flat tube group 30 (hereinafter referred to as non-module NM) in which the refrigerant flows in the opposite direction to the flat tube group 30 of the module M is provided on the upstream side of the refrigerant flow of the module M when functioning as a module. . That is, the flat tube group 30 which is a non-module NM is not adjacent to the bypass piping 40. Further, when the heat exchanger 100b functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the lower header 20, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at the other end of the lower header 20. is formed.

Here, in a region where a single-phase gas refrigerant is considered to exist, there is no increase in the liquid head due to the phase change in the flat tube 31 even if there is an upward flow when the heat exchanger 100b functions as a condenser. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, by providing a non-module NM on the upstream side of the refrigerant flow of the module M when the heat exchanger 100b functions as a condenser, which is a region where single-phase gas refrigerant is thought to exist, bypass The number of piping 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

FIG. 5 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100c according to the first modification of the second embodiment functions as a condenser.

In the heat exchanger 100c according to the first modification of the second embodiment, a non-module NM is provided on the downstream side of the refrigerant flow of the module M when functioning as a condenser. Further, when the heat exchanger 100c functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the upper header 10, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at the other end of the upper header 10. is formed.

Here, in a region where single-phase liquid refrigerant is considered to exist, even if the heat exchanger 100c functions as a condenser and there is an upward flow, there is no increase in the liquid head due to the phase change in the flat tube 31. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, by providing a non-module NM on the downstream side of the refrigerant flow of the module M when the heat exchanger 100c functions as a condenser, which is an area where single-phase liquid refrigerant is thought to exist, bypass The number of piping 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

FIG. 6 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100d according to the second modification of the second embodiment functions as a condenser.

In the heat exchanger 100d according to the second modification of the second embodiment, non-modules NM are provided on the upstream and downstream sides of the refrigerant flow of the module M when functioning as a condenser. Further, when the heat exchanger 100d functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the lower header 20, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at one end of the upper header 10. It is formed. Note that one end of the upper header 10 in which the refrigerant inlet/outlet 52 is formed is located on the opposite side from one end of the lower header 20 in which the refrigerant inlet/outlet 51 is formed.

Here, in a region where a single-phase gas refrigerant is considered to exist, there is no increase in the liquid head due to the phase change in the flat tube 31 even if there is an upward flow when the heat exchanger 100d functions as a condenser. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, by providing a non-module NM on the upstream side of the refrigerant flow of the module M when the heat exchanger 100d functions as a condenser, which is a region where single-phase gas refrigerant is thought to exist, bypass The number of piping 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

In addition, in a region where single-phase liquid refrigerant is thought to exist, even if the heat exchanger 100d functions as a condenser and there is an upward flow, there is no or little increase in the liquid head due to the phase change within the flat tube 31. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, by providing a non-module NM on the downstream side of the refrigerant flow of the module M when the heat exchanger 100d functions as a condenser, which is an area where single-phase liquid refrigerant is thought to exist, bypass The number of piping 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

FIG. 7 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100e according to the third modification of the second embodiment functions as a condenser.

In the heat exchanger 100e according to the third modification of the second embodiment, the module M is composed of three flat tube groups 30 and two bypass pipes 40. That is, the module M of the heat exchanger 100e is a combination of three flat tube groups 30 and bypass piping 40 arranged between two mutually adjacent flat tube groups 30. Note that the module M may include four or more flat tube groups 30 and three or more bypass pipes 40.

In the heat exchanger 100e, a non-module NM is provided on the upstream side of the refrigerant flow of the module M when functioning as a condenser. Further, when the heat exchanger 100e functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the lower header 20, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at the other end of the lower header 20. is formed. The heat exchanger 100e can provide the same effects as the heat exchanger 100b according to the second embodiment.

FIG. 8 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100f according to the fourth modification of the second embodiment functions as a condenser.

In the heat exchanger 100f according to the fourth modification of the second embodiment, the module M includes three flat tube groups 30 and two bypass pipes 40. That is, the module M of the heat exchanger 100f is a combination of three flat tube groups 30 and bypass piping 40 arranged between two mutually adjacent flat tube groups 30. Note that the module M may include four or more flat tube groups 30 and three or more bypass pipes 40.

In the heat exchanger 100f, a non-module NM is provided on the downstream side of the refrigerant flow of the module M when functioning as a condenser. Further, when the heat exchanger 100f functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the upper header 10, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at the other end of the upper header 10. is formed. The heat exchanger 100f can provide the same effects as the heat exchanger 100c according to the first modification of the second embodiment.

FIG. 9 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100g according to the fifth modification of the second embodiment functions as a condenser.

In the heat exchanger 100g according to the fifth modification of the second embodiment, the module M is composed of three flat tube groups 30 and two bypass pipes 40. In other words, the module M of the heat exchanger 100g is a combination of three flat tube groups 30 and bypass piping 40 arranged between two mutually adjacent flat tube groups 30. Note that the module M may include four or more flat tube groups 30 and three or more bypass pipes 40.

In the heat exchanger 100g, non-modules NM are provided on the upstream and downstream sides of the refrigerant flow of the module M when functioning as a condenser. Further, when the heat exchanger 100g functions as a condenser, a refrigerant inlet/outlet 51 serving as a gas refrigerant inlet is formed at one end of the lower header 20, and a refrigerant inlet/outlet 52 serving as a liquid refrigerant outlet is formed at one end of the upper header 10. It is formed. Note that one end of the upper header 10 in which the refrigerant inlet/outlet 52 is formed is located on the opposite side from one end of the lower header 20 in which the refrigerant inlet/outlet 51 is formed. The heat exchanger 100g can provide the same effects as the heat exchanger 100d according to the second modification of the second embodiment.

As described above, when the heat exchanger 100b according to the second embodiment functions as a condenser, the refrigerant flows inside the plurality of flat tube groups 30 in the opposite direction to the upstream side of the refrigerant flow of the plurality of flat tube groups 30. A flowing flat tube group 30 is provided.

Here, in a region where a single-phase gas refrigerant is considered to exist, there is no increase in the liquid head due to the phase change in the flat tube 31 even if there is an upward flow when the heat exchanger 100b functions as a condenser. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, according to the heat exchanger 100b according to the second embodiment, a non-module NM By providing the configuration, the number of bypass pipes 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

Furthermore, when the heat exchanger 100 according to the second embodiment functions as a condenser, the refrigerant flows inside the plurality of flat tube groups 30 in the opposite direction to the downstream side of the refrigerant flow of the plurality of flat tube groups 30. A flowing flat tube group 30 is provided.

Here, in a region where single-phase liquid refrigerant is considered to exist, even if the heat exchanger 100b functions as a condenser and there is an upward flow, there is no increase in the liquid head due to the phase change in the flat tube 31. Since the influence of the head difference is small, there is no need to provide the bypass piping 40. Therefore, according to the heat exchanger 100b according to the second embodiment, a non-module NM By providing the configuration, the number of bypass pipes 40 can be reduced. As a result, the amount of refrigerant for the reduced bypass pipe 40 can be reduced, and the amount of heat of the high temperature refrigerant can be transmitted to the flat tube 31 during defrosting. Furthermore, the structure is simplified and costs can be expected to be reduced.

Embodiment 3.
Embodiment 3 will be described below, but the description of parts that overlap with Embodiments 1 and 2 will be omitted, and the same or corresponding parts as in Embodiments 1 and 2 will be given the same reference numerals.

FIG. 10 is a schematic diagram showing the flow of refrigerant when the heat exchanger 100h according to the third embodiment functions as a condenser.

The heat exchanger 100h according to the third embodiment includes three flat tube groups 30 and bypass piping 40 disposed between two adjacent flat tube groups 30. That is, the heat exchanger 100h has three flat tube groups 30 and two bypass pipes 40. Note that the heat exchanger 100h only needs to have a plurality of bypass pipes 40, and may have three or more bypass pipes 40.

In the heat exchanger 100h, when functioning as a condenser, the diameter r1 of the bypass pipe 40 on the downstream side of the refrigerant flow is smaller than the diameter r2 of the bypass pipe 40 on the upstream side. That is, r1<r2. Note that even when there are three or more bypass pipes 40, the diameter of the bypass pipe 40 on the most downstream side of the refrigerant flow when the heat exchanger 100h functions as a condenser is defined as r1, and the diameter of the bypass pipe 40 on the upstream side is On the other hand, if the diameters of the bypass piping 40 are r2, r3..., then r1<r2<r3....

Here, when the heat exchanger 100h functions as a condenser, the downstream side of the refrigerant flow becomes a low dryness region (high density region), so the bypass piping 40 can be made thinner than on the upstream side. Therefore, when the heat exchanger 100h functions as a condenser, the amount of refrigerant inside the heat exchanger 100h is reduced by making the bypass piping 40 in the low dryness region on the downstream side of the refrigerant flow thinner than on the upstream side. be able to.

As described above, the heat exchanger 100 according to the third embodiment has three or more flat tube groups 30, two or more bypass pipes 40, and has bypass pipes on the downstream side of the refrigerant flow when functioning as a condenser. The diameter of 40 is smaller than the diameter of bypass piping 40 on the upstream side.

According to the heat exchanger 100 according to the third embodiment, by making the bypass pipe 40 in the low dryness region on the downstream side of the refrigerant flow thinner than the upstream side when functioning as a condenser, the heat exchanger 100h can be The amount of refrigerant inside can be reduced.

10 Upper header, 11 First partition, 20 Lower header, 21 Second partition, 30 Flat tube group, 31 Flat tube, 40 Bypass piping, 51 Refrigerant inlet/outlet, 52 Refrigerant inlet/outlet, 100 Heat exchanger, 100a Heat exchanger, 100b Heat exchanger, 100c heat exchanger, 100d heat exchanger, 100e heat exchanger, 100f heat exchanger, 100g heat exchanger, 100h heat exchanger.

Claims

A plurality of flat tube groups constituted by a plurality of flat tubes in which the refrigerant flows in the same direction, with the vertical direction being the tube extending direction and flat surfaces facing each other so as to be parallel to each other;
bypass piping arranged between the adjacent flat tube groups, through which a refrigerant flows in a direction opposite to the adjacent flat tube groups;
an upper header arranged above the plurality of flat tube groups and the bypass piping, into which ends thereof are inserted;
a lower header arranged below the plurality of flat tube groups and the bypass piping, into which ends thereof are inserted;
When acting as a condenser,
The refrigerant is configured to flow downward within the plurality of flat tube groups, and flow upward within the bypass piping,
Inside each of the upper header and the lower header, an end of the bypass piping is arranged below an end of each of the flat tubes. Heat exchanger.
According to claim 1, a flat tube group is provided on the upstream side of the refrigerant flow of the plurality of flat tube groups when functioning as a condenser, the inside of which the refrigerant flows in the opposite direction to the plurality of flat tube groups. heat exchanger.
2. A flat tube group is provided on the downstream side of the refrigerant flow of the plurality of flat tube groups when functioning as a condenser, the inside of which the refrigerant flows in the opposite direction to the plurality of flat tube groups. Heat exchanger described in.
having three or more of the flat tube groups,
having two or more of the bypass pipes,
The heat exchanger according to any one of claims 1 to 3, wherein the diameter of the bypass piping on the downstream side of the refrigerant flow when functioning as a condenser is smaller than the diameter of the bypass piping on the upstream side.
The heat exchanger according to any one of claims 1 to 4, wherein the flow passage cross-sectional area of the bypass pipe is larger than the flow passage cross-sectional area of the flat tube.
A first partition is provided inside the upper header to partition a refrigerant flow path formed inside the upper header,
The heat exchanger according to any one of claims 1 to 5, wherein a second partition is provided inside the lower header to partition a refrigerant flow path formed inside the lower header.