WO2024224637A1 - Heat exchanger, and refrigeration cycle device - Google Patents

Abstract

A heat exchanger (10) comprises a plurality of first heat transfer pipes (21), a plurality of second heat transfer pipes (22), a first lower header (31), a second lower header (32), and a distribution pipe (33). The plurality of first heat transfer pipes extend along the gravity direction (g) and are spaced apart from each other in a direction (X) orthogonal to the gravity direction. The plurality of second heat transfer pipes extend along the gravity direction, are spaced apart from each other in the direction (X), and are spaced apart from each of the plurality of first heat transfer pipes in a direction (Y). The first lower header is connected to a lower end part (21A) of each of the plurality of first heat transfer pipes, and a first space (S1) communicating with internal spaces in each of the plurality of first heat transfer pipes is formed inside the first lower header. The second lower header is connected to a lower end part (22A) of each of the plurality of second heat transfer pipes, and a second space (S2) communicating with internal spaces in each of the plurality of second heat transfer pipes is formed inside the second lower header. The distribution pipe is connected to each of the first lower header and the second lower header, and a third space (S3) communicating with each of the first space and the second space is formed inside the distribution pipe. A plurality of first openings (61) that are spaced apart from each other in the direction (X), and a plurality of second openings (62) that are spaced apart from each other in the direction (X), are formed in the distribution pipe. The third space in the distribution pipe communicates with the first space in the first lower header via the plurality of first openings and communicates with the second space in the second lower header via the plurality of second openings.

Description

Heat exchanger and refrigeration cycle device

This disclosure relates to a heat exchanger and a refrigeration cycle device.

WO 2015/162689 (Patent Document 1) discloses a two-row heat exchanger having a first row of heat transfer tubes and a second row of heat transfer tubes connected in series with the first row of heat transfer tubes.

International Publication No. WO 2015/162689

In the two-row heat exchanger described in Patent Document 1, the first row heat transfer tubes and the second row heat transfer tubes are connected in series with each other, making it difficult to reduce the pressure loss of the refrigerant flowing inside the first row heat transfer tubes and the second row heat transfer tubes.

The main objective of this disclosure is to provide a heat exchanger that can reduce the pressure loss of the refrigerant compared to the above-mentioned two-row heat exchanger, and a refrigeration cycle device equipped with the heat exchanger.

The heat exchanger according to the present disclosure includes a plurality of first heat transfer tubes, a plurality of second heat transfer tubes, a first lower header, a second lower header, and a distribution pipe. The plurality of first heat transfer tubes extend along the direction of gravity and are spaced apart from one another in a first direction perpendicular to the direction of gravity. The plurality of second heat transfer tubes extend along the direction of gravity and are spaced apart from one another in the first direction, and are spaced apart from each of the plurality of first heat transfer tubes in a second direction perpendicular to the direction of gravity and the first direction. The first lower header is connected to the lower end of each of the plurality of first heat transfer tubes, and a first space communicating with the internal space of each of the plurality of first heat transfer tubes is formed therein. The second lower header is connected to the lower end of each of the plurality of second heat transfer tubes, and a second space communicating with the internal space of each of the plurality of second heat transfer tubes is formed therein. The distribution pipe is connected to each of the first lower header and the second lower header, and a third space communicating with each of the first space and the second space is formed therein. The distribution pipe has a plurality of first openings spaced apart from one another in the first direction, and a plurality of second openings spaced apart from one another in the first direction. The third space of the distribution pipe is in communication with the first space of the first lower header through the plurality of first openings, and is in communication with the second space of the second lower header through the plurality of second openings.

According to the present disclosure, it is possible to provide a heat exchanger that can reduce the pressure loss of the refrigerant compared to the above-mentioned two-row heat exchanger, and a refrigeration cycle device equipped with the heat exchanger.

1 is a diagram showing an example of a refrigeration cycle device according to an embodiment of the present invention; FIG. 2 is a perspective view showing an example of a second heat exchanger according to the first embodiment. 3 is a view of the second heat exchanger shown in FIG. 2 as viewed from a second direction. FIG. FIG. 4 is a partial cross-sectional view taken along the line IV-IV in FIG. 3 is a partial cross-sectional view for explaining the flow of a gas-liquid two-phase refrigerant that has flowed into the second heat exchanger in a first state in which the second heat exchanger shown in FIG. 2 functions as an evaporator. FIG. FIG. 6 is a cross-sectional view showing an example of a heat exchanger according to a second embodiment. FIG. 11 is a cross-sectional view showing a modified example of the heat exchanger according to the second embodiment. FIG. 11 is a cross-sectional view showing an example of a heat exchanger according to a third embodiment. FIG. 11 is a cross-sectional view showing a first modified example of the heat exchanger according to the third embodiment. FIG. 11 is a cross-sectional view showing a second modified example of the heat exchanger according to the third embodiment. FIG. 11 is a cross-sectional view showing an example of a heat exchanger according to a fourth embodiment.

Below, an embodiment of the present disclosure will be described with reference to the drawings. Note that the same or corresponding parts in the drawings will be given the same reference numbers and their description will not be repeated.

<Configuration of refrigeration cycle device 1>
A refrigeration cycle apparatus 1 according to an embodiment of the present disclosure will be described with reference to Fig. 1. As shown in Fig. 1, the refrigeration cycle apparatus 1 includes a refrigerant circuit through which a refrigerant circulates. The refrigerant circuit includes a compressor 2, a first heat exchanger 3, a throttling device 4, a second heat exchanger 10, and a flow path switching device 5. The second heat exchanger 10 is the heat exchanger according to the embodiment of the present disclosure.

Compressor 2 compresses the refrigerant and is, for example, a rotary compressor, scroll compressor, screw compressor, or reciprocating compressor.

The first heat exchanger 3 is provided to exchange heat between the refrigerant circulating through the refrigerant circuit and a first heat transport medium other than the refrigerant. The first heat exchanger 3 is, for example, an indoor heat exchanger. The first heat exchanger 3 is, for example, a fin-and-tube heat exchanger, a microchannel heat exchanger, a finless heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-tube heat exchanger, or a plate heat exchanger.

The throttling device 4 expands the refrigerant to reduce its pressure. The throttling device 4 is, for example, an electric expansion valve. Note that the throttling device 4 is not limited to an electric expansion valve, and may be a mechanical expansion valve that uses a diaphragm in the pressure receiving section, or a capillary tube, etc.

The flow path switching device 5 switches the flow path of the refrigerant circulating through the refrigerant circuit. The flow path switching device 5 switches between a first state in which the first heat exchanger 3 acts as a condenser and the second heat exchanger 10 acts as an evaporator, and a second state in which the first heat exchanger 3 acts as an evaporator and the second heat exchanger 10 acts as a condenser. In FIG. 1, the solid arrow indicates the direction in which the refrigerant flows in the first state, and the dashed arrow indicates the direction in which the refrigerant flows in the second state. The flow path switching device 5 is, for example, a four-way valve.

The second heat exchanger 10 is provided to exchange heat between the refrigerant circulating in the refrigerant circuit and a second heat transport medium other than the refrigerant. The second heat exchanger 10 is connected to the first heat exchanger 3 in the refrigerant circuit via a throttling device 4. The second heat exchanger 10 includes a first inlet/outlet pipe 11 and a second inlet/outlet pipe 12 through which the refrigerant flows in and out. In the first state, the first inlet/outlet pipe 11 serves as the inlet for the refrigerant in the second heat exchanger 10, and the second inlet/outlet pipe 12 serves as the outlet for the refrigerant in the second heat exchanger 10. In the second state, the second inlet/outlet pipe 12 serves as the inlet for the refrigerant in the second heat exchanger 10, and the first inlet/outlet pipe 11 serves as the outlet for the refrigerant in the second heat exchanger 10. The second heat exchanger 10 is a heat exchanger according to an embodiment of the present disclosure. The second heat transport medium is not particularly limited, but may be, for example, air.

The refrigeration cycle device 1 further includes, for example, a first supply unit 6 that supplies a first heat transport medium to the first heat exchanger 3 and a second supply unit 7 that supplies a second heat transport medium to the second heat exchanger 10. The first supply unit 6 and the second supply unit 7 are, for example, fans.

The refrigerant circulating through the refrigerant circuit of the refrigeration cycle device 1 may be any refrigerant. For example, the refrigerant circulating through the refrigerant circuit of the refrigeration cycle device 1 may be R32, R290, R1234yf, etc., which have a small GWP (Global Warming Potential) and a high COP (Coefficient of Performance).

Below, the second heat exchanger 10 according to embodiments 1 to 5 will be described with reference to Figures 2 to 11 as specific configuration examples of the heat exchanger according to the embodiments of the present disclosure.

Embodiment 1.
<Configuration of second heat exchanger 10>
The second heat exchanger 10 according to the first embodiment will be described with reference to Figures 2 to 4. In the following, for convenience of explanation, a Z direction along the direction of gravity, an X direction (first direction) perpendicular to the direction of gravity, and a Y direction (second direction) perpendicular to the direction of gravity and the X direction will be introduced. The second heat exchanger 10 is disposed in the refrigeration cycle device 1 such that the flow direction A of the second heat transport medium is aligned with the Y direction.

As shown in Figures 2 and 3, the second heat exchanger 10 includes a first inlet/outlet pipe 11, a second inlet/outlet pipe 12, a plurality of first heat transfer pipes 21, a plurality of second heat transfer pipes 22, a first lower header 31, a second lower header 32, a distribution pipe 33, a first upper header 41, a second upper header 42, a branch pipe 43, and a plurality of fins 50.

As shown in Figures 2 and 3, each of the multiple first heat transfer tubes 21 extends along the gravity direction g and is arranged at intervals from one another in the X direction. The lower end of each of the multiple first heat transfer tubes 21 is connected to the first lower header 31. The upper end of each of the multiple first heat transfer tubes 21 is connected to the first upper header 41.

2 and 3, each of the second heat transfer tubes 22 extends along the direction of gravity g and is spaced apart from one another in the X direction. Each of the second heat transfer tubes 22 is spaced apart from one of the first heat transfer tubes 21 in the Y direction. In the flow direction A of the second heat transport medium, the second heat transfer tubes 22 are located downstream (e.g., downwind) of the first heat transfer tubes 21. The lower end of each of the second heat transfer tubes 22 is connected to the second lower header 32. The upper end of each of the second heat transfer tubes 22 is connected to the second upper header 42.

3, the position of the second heat transfer tube 22 in the X direction is, for example, the same as the position of the first heat transfer tube 21 in the X direction. When viewed from the Y direction, the second heat transfer tube 22 is arranged so as to overlap with the first heat transfer tube 21, for example. As long as the second heat transfer tube 22 is arranged at a distance from the first heat transfer tube 21 in the Y direction, the relative positional relationship between the first heat transfer tube 21 and the second heat transfer tube 22 in the X direction is not particularly limited. The position of the second heat transfer tube 22 in the X direction may be different from the position of the first heat transfer tube 21 in the X direction. In other words, the second heat transfer tube 22 only needs to be arranged at a distance from the first heat transfer tube 21 in the Y direction, and may be in the same position as the first heat transfer tube 21 in the X direction or may be in a different position from the first heat transfer tube 21. When viewed from the Z direction, the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 may be arranged in a staggered manner. When viewed from the Y direction, each of the multiple second heat transfer tubes 22 may be arranged at the midpoint between two first heat transfer tubes 21 adjacent to each other in the X direction.

The cross-sectional shape perpendicular to the Z direction of each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 is, for example, a flat shape. Note that the cross-sectional shape perpendicular to the Z direction of each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 may be any shape, and may be, for example, a circular shape.

As shown in FIG. 2 and FIG. 3, each of the first lower header 31, the second lower header 32, and the distribution pipe 33 extends along the X direction. As described above, the first lower header 31 is connected to the lower end of each of the multiple first heat transfer tubes 21. The first lower header 31 can distribute the refrigerant to each of the multiple first heat transfer tubes 21. As described above, the second lower header 32 is connected to the lower end of each of the multiple second heat transfer tubes 22. The second lower header 32 can distribute the refrigerant to each of the multiple second heat transfer tubes 22. The distribution pipe 33 is connected to each of the first lower header 31 and the second lower header 32. The distribution pipe 33 can distribute the refrigerant to the first lower header 31 and the second lower header 32.

2 and 3, the distribution pipe 33 has one end 33A and the other end 33B in the X direction. One end 33A of the distribution pipe 33 is connected to the first inlet/outlet pipe 11. One end 33A of the distribution pipe 33 is disposed at a position farther from the other end 33B in the X direction than the first heat transfer tube 21 that is closest to the one end 33A. The other end 33B of the distribution pipe 33 is disposed at a position farther from the one end 33A in the X direction than the first heat transfer tube 21. The length in the X direction between one end 33A and the other end 33B of the distribution pipe 33 is longer than the distance between the first heat transfer tube 21 and the first heat transfer tube 21.

The distribution pipe 33 connects the first inlet/outlet pipe 11 to the first lower header 31 and the second lower header 32. The first lower header 31 and the second lower header 32 are connected in parallel to the distribution pipe 33 and the first inlet/outlet pipe 11.

Each of the first lower header 31 and the second lower header 32 is joined to the distribution pipe 33. The first lower header 31, the second lower header 32, and the distribution pipe 33 can be prepared as an integrated lower header 30 joined together. This joining method is, for example, brazing. Note that the joining method is not limited to brazing, and may be, for example, press fitting, crimping, or bonding.

The cross-sectional shape of each of the first lower header 31 and the second lower header 32 perpendicular to the X direction is, for example, rectangular. Note that the cross-sectional shape of each of the first lower header 31 and the second lower header 32 perpendicular to the X direction may be any shape, for example, circular. The cross-sectional shape of the distribution pipe 33 perpendicular to the X direction is, for example, circular. The cross-sectional shape of the distribution pipe 33 perpendicular to the X direction may be any shape, for example, rectangular.

The first upper header 41 and the second upper header 42 each extend along the X direction. The first upper header 41 can distribute the refrigerant to each of the multiple first heat transfer tubes 21. The second upper header 42 can distribute the refrigerant to each of the multiple second heat transfer tubes 22. The branch pipe 43 connects each of the first upper header 41 and the second upper header 42 to the second inlet/outlet pipe 12. The first upper header 41 and the second upper header 42 each are connected in parallel to the second inlet/outlet pipe 12.

Each of the multiple fins 50 is, for example, a plate fin extending along the Y direction and the Z direction. Each of the multiple fins 50 has, for example, an upstream portion 51 extending from the first heat transfer tube 21 to the opposite side of the second heat transfer tube 22 in the Y direction, a downstream portion 52 extending from the second heat transfer tube 22 to the opposite side of the first heat transfer tube 21 in the Y direction, and a central portion 53 spanning between the first heat transfer tube 21 and the second heat transfer tube 22 in the Y direction.

The shape of each of the multiple fins 50 is not particularly limited. Each of the multiple fins 50 may be, for example, a corrugated fin. Furthermore, the second heat exchanger 10 may be a finless type heat exchanger that does not have fins.

As shown in FIG. 3, when viewed from the Y direction, each of the multiple second heat transfer tubes 22 is arranged to overlap, for example, each of the multiple first heat transfer tubes 21. When viewed from the Y direction, the second lower header 32 is arranged to overlap, for example, the first lower header 31.

Next, the configuration of the first lower header 31, the second lower header 32, and the distribution pipe 33 will be further explained with reference to Figure 4.

As shown in FIG. 4, a first space S1 is formed inside the first lower header 31, which is in communication with the internal space of each of the multiple first heat transfer tubes 21. A second space S2 is formed inside the second lower header 32, which is in communication with the internal space of each of the multiple second heat transfer tubes 22. A third space S3 is formed inside the distribution pipe 33, which is in communication with each of the first space S1 of the first lower header 31 and the second space S2 of the second lower header 32.

As shown in FIG. 4, a plurality of first insertion holes 34 are formed in the first lower header 31. Each of the plurality of first insertion holes 34 is a through hole that reaches from the outer peripheral surface to the inner peripheral surface of the first lower header 31. The plurality of first insertion holes 34 are arranged at intervals from one another in the Y direction. Each of the plurality of first heat transfer tubes 21 is inserted into one of the first insertion holes 34.

As shown in FIG. 4, the second lower header 32 has a plurality of second insertion holes 35 (see FIG. 4). Each of the plurality of second insertion holes 35 is a through hole that reaches from the outer peripheral surface to the inner peripheral surface of the second lower header 32. The plurality of second insertion holes 35 are arranged at intervals from one another in the Y direction. Each of the plurality of second heat transfer tubes 22 is inserted into one of the second insertion holes 35.

As shown in FIG. 4, the distribution pipe 33 is formed with a plurality of first openings 61 and a plurality of second openings 62. Each of the plurality of first openings 61 and the plurality of second openings 62 is a through hole that reaches from the outer peripheral surface of the distribution pipe 33 to the inner peripheral surface. The plurality of first openings 61 are arranged at intervals from each other in the X direction. Each of the plurality of first openings 61 has, for example, an equivalent configuration to each other. The relative positions of each of the plurality of first openings 61 with respect to the inner peripheral surface of the first lower header 31 are, for example, equal to each other. Each of the plurality of first openings 61 is arranged side by side on a straight line extending along the X direction. The plurality of second openings 62 are arranged side by side on the X direction. Each of the plurality of second openings 62 has, for example, an equivalent configuration to each other. The relative positions of each of the plurality of second openings 62 with respect to the inner peripheral surface of the second lower header 32 are, for example, equal to each other. Each of the plurality of second openings 62 is arranged side by side on a straight line extending along ... The relative positions of each of the multiple first openings 61 with respect to the inner circumferential surface of the first lower header 31 may be different from each other. For example, in the X direction, the first opening 61 located on the other end 33B side of the distribution pipe 33 may be disposed lower than the first opening 61 located on the one end 33A side of the distribution pipe 33. Similarly, the relative positions of each of the multiple second openings 62 with respect to the inner circumferential surface of the second lower header 32 may be different from each other.

As shown in FIG. 4, each of the multiple first openings 61 connects the third space S3 to the first space S1. Each of the multiple second openings 62 connects the third space S3 to the second space S2. The third space S3 of the distribution pipe 33 connects to the first space S1 of the first lower header 31 through each of the multiple first openings 61, and connects to the second space S2 of the second lower header 32 through each of the multiple second openings 62.

As shown in FIG. 4, each of the multiple first openings 61 is disposed, for example, above the lower end 21A of each of the multiple first heat transfer tubes 21. Each of the multiple first openings 61 is disposed, for example, below the center CP of the distribution pipe 33. In a cross section perpendicular to the Y direction, the hole axis of each of the multiple first openings 61 is inclined, for example, with respect to each of the X direction and the Z direction.

As shown in FIG. 4, each of the second openings 62 is disposed, for example, above the lower end 22A of each of the second heat transfer tubes 22. Each of the second openings 62 is disposed, for example, below the center CP of the distribution pipe 33. In a cross section perpendicular to the Y direction, the hole axis of each of the second openings 62 is inclined, for example, with respect to the X direction and the Z direction.

Each of the multiple first openings 61 is arranged at an interval from each of the multiple first heat transfer tubes 21 in the X direction, for example. Each of the multiple first openings 61 is arranged, for example, between two first heat transfer tubes 21 adjacent in the X direction. Each of the multiple second openings 62 is arranged, for example, at an interval from each of the multiple second heat transfer tubes 22 in the X direction. Each of the multiple second openings 62 is arranged, for example, between two second heat transfer tubes 22 adjacent in the X direction. Note that each of the multiple first openings 61 may be arranged without an interval from each of the multiple first heat transfer tubes 21 in the X direction. Each of the multiple second openings 62 may be arranged without an interval from each of the multiple second heat transfer tubes 22 in the X direction.

As shown in FIG. 4, in a cross section perpendicular to the X direction, the first lower header 31 is in a line-symmetrical relationship with the second lower header 32 with respect to, for example, an imaginary straight line CL that passes through the center CP of the distribution pipe 33 and extends along the Z direction. In a cross section perpendicular to the X direction, each of the multiple first openings 61 is in a line-symmetrical relationship with, for example, each of the multiple second openings 62 with respect to the imaginary straight line CL.

As shown in FIG. 4, the upper end of the distribution pipe 33 is positioned, for example, higher than the upper ends of the first lower header 31 and the second lower header 32.

The opening area of each of the multiple first openings 61 and multiple second openings 62 on the outer peripheral surface of the distribution pipe 33 is smaller than the opening area (flow path cross-sectional area) of the distribution pipe 33 in a cross section perpendicular to the X-direction. The flow resistance of the refrigerant flowing through each of the multiple first openings 61 or multiple second openings 62 is greater than the flow resistance of the refrigerant flowing through the distribution pipe 33. On the outer peripheral surface of the distribution pipe 33, the opening area of each of the multiple first openings 61 is equal to the opening area of each of the multiple second openings 62, for example.

The opening shape of each of the multiple first openings 61 and the multiple second openings 62 is, for example, a square shape. Note that the opening shape of each of the multiple first openings 61 and the multiple second openings 62 may be any shape, for example, a circular shape.

<Refrigerant flow formed in the second heat exchanger 10 in the refrigeration cycle device 1>
The flow of the refrigerant formed in the second heat exchanger 10 when the refrigeration cycle apparatus 1 is in the first state or the second state will be described below.

When the refrigeration cycle device 1 is in the first state, the gas-liquid two-phase refrigerant decompressed by the throttling device 4 flows into the first inlet/outlet pipe 11 of the second heat exchanger 10. As shown in FIG. 5, the gas-liquid two-phase refrigerant that flows into the first inlet/outlet pipe 11 of the second heat exchanger 10 in the first state flows into the third space S3 of the distribution pipe 33.

A portion of the gas-liquid two-phase refrigerant that flows into the third space S3 flows from the third space S3 through each of the multiple first openings 61 into the first space S1 of the first lower header 31 (see arrow F1 in FIG. 5). Another portion of the gas-liquid two-phase refrigerant that flows into the third space S3 flows through each of the multiple second openings 62 into the second space S2 of the second lower header 32 (see arrow F2 in FIG. 5). The remainder of the gas-liquid two-phase refrigerant that flows into the third space S3 flows in the X direction within the third space S3 and reaches the other end 33B of the distribution pipe 33. In this way, the gas-liquid two-phase refrigerant that flows into the third space S3 is distributed to the first space S1 of the first lower header 31 and the second space S2 of the second lower header 32. The gas-liquid two-phase refrigerant that flows into the first space S1 flows into the interiors of the first heat transfer tubes 21 from the lower end portions 21A of the first heat transfer tubes 21 (see arrows F3 and F5 in FIG. 5). The gas-liquid two-phase refrigerant that flows into the second space S2 flows into the interiors of the second heat transfer tubes 22 from the lower end portions 22A of the second heat transfer tubes 22 (see arrows F4 and F6 in FIG. 5).

The two-phase gas-liquid refrigerant flowing through each of the multiple first heat transfer tubes 21 exchanges heat with the heat transport medium to change to gas phase refrigerant, and then merges at the first upper header 41. Similarly, the two-phase gas-liquid refrigerant flowing through each of the multiple second heat transfer tubes 22 exchanges heat with the heat transport medium to change to gas phase refrigerant, and then merges at the second upper header 42. The gas phase refrigerant merged at the first upper header 41 and the gas phase refrigerant merged at the second upper header 42 merge at the branch pipe 43 and flow out from the second inlet/outlet pipe 12.

In the second state, the gas-phase refrigerant flowing into the second heat exchanger 10 from the second inlet/outlet pipe 12 is distributed to the first upper header 41 and the second upper header 42 via the branch pipe 43, and is further distributed from the first upper header 41 to the multiple first heat transfer pipes 21 and from the second upper header 42 to each of the multiple second heat transfer pipes 22. The gas-liquid two-phase refrigerant flowing through each of the multiple first heat transfer pipes 21 exchanges heat with the heat transport medium and changes to a gas-liquid two-phase refrigerant or a liquid phase refrigerant, and then merges at the first lower header 31. Similarly, the gas-phase refrigerant flowing through each of the multiple second heat transfer pipes 22 exchanges heat with the heat transport medium and changes to a gas-liquid two-phase refrigerant or a liquid phase refrigerant, and then merges at the second lower header 32. The refrigerant that merges in the first lower header 31 and the refrigerant that merges in the second lower header 32 merge in the distribution pipe 33 and flow out from the first inlet/outlet pipe 11.

<Effects of the second heat exchanger 10>
In the second heat exchanger 10, the third space S3 of the distribution pipe 33 communicates with the first space S1 of the first lower header 31 through the multiple first openings 61, and communicates with the second space S2 of the second lower header 32 through the multiple second openings 62. The multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 are connected in parallel to the distribution pipe 33. Therefore, in the second heat exchanger 10, the pressure loss of the refrigerant flowing through each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 (hereinafter, also simply referred to as pressure loss in the tube) can be reduced compared to the above-mentioned two-row heat exchanger in which the first row heat transfer tubes and the second row heat transfer tubes are connected in series to each other.

In particular, in the second heat exchanger 10, the pressure loss within the tubes can be reduced even when the width in the X direction of the internal space of each of the first heat transfer tubes 21 and the second heat transfer tubes 22 is relatively narrow.

In the second heat exchanger 10, each of the first heat transfer tubes 21 and the second heat transfer tubes 22 extends along the gravity direction g. Each of the first heat transfer tubes 21 is arranged at intervals in the X direction. Each of the second heat transfer tubes 22 is arranged at intervals in the X direction. Each of the first openings 61 connecting the first space S1 and the third space S3 is arranged at intervals in the X direction. Furthermore, each of the second openings 62 connecting the second space S2 and the third space S3 is arranged at intervals in the X direction. Therefore, in the first state, the dryness of the gas-liquid two-phase refrigerant flowing from the distribution pipe 33 through the first lower header 31 or the second lower header 32 into each of the first heat transfer tubes 21 and the second heat transfer tubes 22 can be made uniform. Specifically, in the first state, the gas-liquid two-phase refrigerant is separated into liquid refrigerant and gas refrigerant by gravity to form a liquid level (gas-liquid interface) in the third space S3. Since the first openings 61 are arranged at intervals in the X direction, the relative positions of the first openings 61 with respect to the liquid level are equal to each other. Therefore, in the second heat exchanger 10, the heat transfer tubes extend horizontally and are arranged at intervals in the gravity direction. Therefore, compared with a heat exchanger in which a distributor (distribution pipe) extends along the gravity direction, the weight ratio of the liquid refrigerant and the gas refrigerant in the gas-liquid two-phase refrigerant flowing through each of the first openings 61 can be uniform, and the dryness of the gas-liquid two-phase refrigerant flowing into each of the first heat transfer tubes 21 and the second heat transfer tubes 22 can be uniform. As a result, in the second heat exchanger 10, the heat exchange amount can be made uniform between each of the multiple first heat transfer tubes 21 and between each of the multiple second heat transfer tubes 22, so that the heat exchange amount is prevented from becoming non-uniform and the heat exchange performance is prevented from deteriorating. In other words, the second heat exchanger 10 can exhibit the desired heat exchanger performance.

Furthermore, in the second heat exchanger 10, the opening area of each of the multiple first openings 61 and multiple second openings 62 on the outer peripheral surface of the distribution pipe 33 is smaller than the opening area (flow path cross-sectional area) of the distribution pipe 33 in a cross section perpendicular to the X direction. Therefore, the gas-liquid two-phase refrigerant that flows into the third space S3 from the first inlet/outlet pipe 11 easily flows to the area on the other end 33B side away from the first inlet/outlet pipe 11. As a result, the dryness of the gas-liquid two-phase refrigerant that flows into each of the multiple first heat transfer pipes 21 and the multiple second heat transfer pipes 22 is uniform regardless of the distance from one end 33A of the distribution pipe 33 in the X direction.

In the second heat exchanger 10, the first lower header 31, the second lower header 32, and the distribution pipe 33 can be prepared as an integral lower header joined together. By preparing the first lower header 31, the second lower header 32, and the distribution pipe 33 as an integral lower header joined together, the lower header can be easily assembled with each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 in the manufacturing method of the second heat exchanger 10. Furthermore, by doing so, the second heat exchanger 10 can ensure the desired strength.

In the second heat exchanger 10, the lower end 21A of each of the multiple first heat transfer tubes 21 is positioned lower than each of the multiple first openings 61 in the first space S1, so the amount of liquid refrigerant remaining in the first space S1 in the first state can be reduced compared to when the lower end 21A of each of the multiple first heat transfer tubes 21 is positioned higher than each of the multiple first openings 61.

Generally, the quality of the refrigerant flowing into the evaporator is 0.1 or more, the saturation temperature of the refrigerant flowing through the evaporator is 10°C or less, and the void fraction of the gas-liquid two-phase refrigerant flowing through the evaporator is higher than 0.5 regardless of the type of refrigerant. The void fraction of the gas-liquid two-phase refrigerant is the volume ratio of the gas-phase refrigerant in the gas-liquid two-phase refrigerant. Therefore, in the first state in which the second heat exchanger 10 acts as an evaporator, the void fraction of the gas-liquid two-phase refrigerant flowing into the distribution pipe 33 is expected to be higher than 0.5. When the void fraction of the gas-liquid two-phase refrigerant flowing into the distribution pipe 33 is higher than 0.5, the gas-liquid interface of the gas-liquid two-phase refrigerant is expected to be formed below the center CP in the distribution pipe 33.

In the second heat exchanger 10, each of the multiple first openings 61 and multiple second openings 62 is formed below the center CP of the distribution pipe 33. Therefore, in the first state, when a gas-liquid two-phase refrigerant with a void fraction higher than 0.5 flows into the distribution pipe 33 and the gas-liquid interface of the gas-liquid two-phase refrigerant is formed below the middle position (center CP) of the distribution pipe 33 in the Z direction, the gas-liquid interface is likely to be formed inside each of the multiple first openings 61 and multiple second openings 62. As a result, in the second heat exchanger 10, the liquid refrigerant or gas refrigerant in the gas-liquid two-phase refrigerant is unlikely to be unevenly distributed to each of the first lower header 31 and the second lower header 32, and the gas-liquid two-phase refrigerant can be distributed relatively evenly.

Embodiment 2.
Unless otherwise specified, the second heat exchanger 110 according to the second embodiment shown in FIG. 6 has the same configuration as the second heat exchanger 10 according to the first embodiment and exerts the same effects.

As shown in FIG. 6, in the second heat exchanger 110, the first lower header 31 and the second lower header 32 are each integrally formed with each other as part of the lower header 30. The distribution pipe 33 is disposed inside the lower header 30.

Specifically, the lower header 30 includes a distribution pipe 33 and an outer casing member 36 that houses the distribution pipe 33 therein. The outer casing member 36 has a lower wall portion 36A and an upper wall portion 36B. A portion of the inner circumferential surface of each of the lower wall portion 36A and the upper wall portion 36B faces the first space S1. The other portion of the inner circumferential surface of each of the lower wall portion 36A and the upper wall portion 36B faces the second space S2.

The outer casing member 36 is formed with a plurality of first insertion holes 34 and a plurality of second insertion holes 35. Each of the plurality of first insertion holes 34 and the plurality of second insertion holes 35 is a through hole that reaches from the outer peripheral surface of the upper wall portion 36B of the outer casing member 36 to the inner peripheral surface (ceiling surface).

The distribution pipe 33 has a first portion 33C and a second portion 33D that face each other in the direction of gravity g across the third space S3. The first portion 33C, which is located relatively lower, includes the lower end of the distribution pipe 33. The second portion 33D, which is located relatively lower, includes the upper end of the distribution pipe 33.

The first portion 33C of the distribution pipe 33 is joined to the lower wall portion 36A of the outer casing member 36. The second portion 33D of the distribution pipe 33 is joined to the upper wall portion 36B of the outer casing member 36. Preferably, the first portion 33C of the distribution pipe 33 is joined to the center portion of the lower wall portion 36A in the X direction. Preferably, the second portion 33D of the distribution pipe 33 is joined to the center portion of the upper wall portion 36B in the X direction, for example. The joining method is, for example, brazing. Note that the joining method is not limited to brazing, and may be, for example, press fitting, crimping, or adhesion. The lower wall portion 36A has an inner bottom surface 361 facing upward. The upper wall portion 36B has a ceiling surface 362 facing downward and facing the inner bottom surface 361. A portion of each of the inner bottom surface 361 and the ceiling surface 362 in the X direction faces the first space S1. The other part of each of the inner bottom surface 361 and the ceiling surface 362 in the X direction faces the second space S2. The remaining part of each of the inner bottom surface 361 and the ceiling surface 362 in the X direction is joined to the distribution pipe 33. Each of the inner bottom surface 361 and the ceiling surface 362 is, for example, a flat surface.

The distribution pipe 33 divides the internal space of the outer casing member 36 of the lower header 130 into a first space S1, a second space S2, and a third space S3.

In the second heat exchanger 110, the distribution pipe 33 is housed inside the outer casing member 36 of the lower header 30, so the handleability of the lower header 130 is further improved compared to the lower header 30 of the second heat exchanger 10.

In addition, in the second heat exchanger 110, the first portion 33C and the second portion 33D are each joined to the lower header 30, so that deformation of the outer casing member 36 is suppressed when internal pressure is applied to each of the first space S1, the second space S2, and the third space S3. In other words, in the second heat exchanger 110, the pressure resistance of the lower header 130 is improved.

Preferably, the first portion 33C and the second portion 33D are joined to the center portions of the lower wall portion 36A and the upper wall portion 36B in the X direction. In this way, deformation of the above-mentioned center portions, which are most susceptible to deformation in the outer casing member 36 in a cross section perpendicular to the X direction, can be suppressed.

<Modifications of the second heat exchanger 110>
The second heat exchanger 110 according to the second embodiment can be modified in the same manner as the second heat exchanger 10 according to the first embodiment. Furthermore, the second heat exchanger 110 can be modified as follows.

As shown in FIG. 7, the lower end 21A of each of the first heat transfer tubes 21 may be in contact with the outer circumferential surface 33E of the distribution tube 33. The lower end 22A of each of the second heat transfer tubes 22 may be in contact with the outer circumferential surface 33E of the distribution tube 33.

The lower end 21A and the lower end 22A are in contact with the upper half of the outer circumferential surface 33E of the distribution pipe 33. Each of the first openings 61 and the second openings 62 opens into the lower half of the outer circumferential surface 33E of the distribution pipe 33.

In the modified example shown in FIG. 7, the manufacturing method involves butting each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 against the distribution tube 33, making it easy to manage the amount of insertion of each of the multiple first heat transfer tubes 21 and the multiple second heat transfer tubes 22 into the distribution tube 33.

Embodiment 3.
Unless otherwise specified, the second heat exchanger 210 according to the third embodiment shown in FIG. 8 has the same configuration as the second heat exchanger 110 according to the second embodiment and exerts the same effects.

As shown in FIG. 8, the second heat exchanger 210 has a lower header 230. The outer member 36 of the lower header 230 has a first inner bottom surface 3611 facing the first space S1 and a second inner bottom surface 3612 facing the second space S2. The center CP of the distribution pipe 33 is located below at least one of a first virtual straight line CL2 passing through the center in the Z direction between the first inner bottom surface 3611 and the first ceiling surface 3621 and a second virtual straight line passing through the center in the Z direction between the second inner bottom surface 3612 and the second ceiling surface 3622. In this case, the lower end portion 33C1 of the distribution pipe 33 is located below at least one of the first inner bottom surface 3611 and the second inner bottom surface 3612. Preferably, the center CP of the distribution pipe 33 is disposed below each of a first imaginary straight line CL2 passing through the center in the Z direction between the first inner bottom surface 3611 and the first ceiling surface 3621, and a second imaginary straight line passing through the center in the Z direction between the second inner bottom surface 3612 and the second ceiling surface 3622. Preferably, the lower end 33C1 of the distribution pipe 33 is disposed below each of the first inner bottom surface 3611 and the second inner bottom surface 3612.

The outer member 36 further has, for example, a first inner bottom surface 3611 and a concave surface 3613 that is concave downward relative to the second space S2. The outer peripheral surface of the first portion 33C of the distribution pipe 33 is joined to the concave surface 3613.

In this way, the distance in the Z direction between the first inner bottom surface 3611 and the first opening 61 shown in FIG. 8 is shorter than the distance in the Z direction between the inner bottom surface 361 and the first opening 61 shown in FIG. 7. In other words, the relative position in the Z direction of the first opening 61 with respect to the first inner bottom surface 3611 in the lower header 230 is lower than the relative position in the Z direction of the first opening 61 with respect to the first inner bottom surface 3611 in the lower header 130. As a result, in the second heat exchanger 210, the gas-liquid two-phase refrigerant flowing from the third space S3 through the first opening 61 to the first space S1 in the first state is blown out to a lower position in the first space S1 compared to the second heat exchanger 110, so that the amount of liquid refrigerant remaining in the first space S1 can be reduced.

Furthermore, in the second heat exchanger 210 shown in FIG. 8, the Z-direction distance between the second inner bottom surface 3612 and the second opening 62 is also shorter than the Z-direction distance between the inner bottom surface 361 and the first opening 61 shown in FIG. 7, so the amount of liquid refrigerant remaining in the second space S2 in the first state can be reduced compared to the second heat exchanger 110.

Furthermore, in the second heat exchanger 210 shown in FIG. 8, the distribution pipe 33 can be joined to the outer casing member 36 over a wider area than in the second heat exchanger 110 shown in FIG. 7, so the pressure resistance of the lower header 230 can be further improved compared to the lower header 130.

<Modification of the second heat exchanger 210>
The second heat exchanger 210 according to the third embodiment can be modified in the same manner as the second heat exchanger 10 according to the first embodiment or the second heat exchanger 110 according to the second embodiment. Furthermore, the second heat exchanger 210 can be modified as follows.

9, the outer member 36 of the lower header 230 has a first ceiling surface 3621 facing the first space S1 and a second ceiling surface 3622 facing the second space S2. The center CP of the distribution pipe 33 may be located above at least one of a first imaginary straight line CL2 passing through the center in the Z direction between the first inner bottom surface 3611 and the first ceiling surface 3621, and a second imaginary straight line passing through the center in the Z direction between the second inner bottom surface 3612 and the second ceiling surface 3622. In this case, the upper end portion 33D1 of the distribution pipe 33 is located above at least one of the first ceiling surface 3621 and the second ceiling surface 3622. Preferably, the center CP of the distribution pipe 33 is located above both a first virtual straight line CL2 passing through the center in the Z direction between the first inner bottom surface 3611 and the first ceiling surface 3621, and a second virtual straight line passing through the center in the Z direction between the second inner bottom surface 3612 and the second ceiling surface 3622.

The outer member 36 further has a concave surface 3623 that is concave upward relative to, for example, the first ceiling surface 3621 and the second ceiling surface 3622. The outer peripheral surface of the second portion 33D of the distribution pipe 33 is joined to the concave surface 3623.

10, the lower end 33C1 of the distribution pipe 33 may be disposed below at least one of the first inner bottom surface 3611 and the second inner bottom surface 3612, and the upper end 33D1 of the distribution pipe 33 may be disposed above at least one of the first ceiling surface 3621 and the second ceiling surface 3622. In this case, the center CP of the distribution pipe 33 is disposed so as to overlap at least one of the imaginary straight line CL2 passing through the center in the Z direction between the first inner bottom surface 3611 and the first ceiling surface 3621, and the imaginary straight line passing through the center in the Z direction between the second inner bottom surface 3612 and the second ceiling surface 3622. Preferably, the lower end 33C1 of the distribution pipe 33 is disposed below each of the first inner bottom surface 3611 and the second inner bottom surface 3612, and the upper end 33D1 of the distribution pipe 33 is disposed above each of the first ceiling surface 3621 and the second ceiling surface 3622.

In the second heat exchanger 210 shown in FIG. 10, the distribution pipe 33 can be joined to the outer casing member 36 over a wider area than in the second heat exchanger 210 shown in FIG. 8, so the pressure resistance of the lower header 230 can be further improved. In addition, the lower header 230 shown in FIG. 10 can be made smaller in size in the direction of the lower header 2Z shown in FIG. 8.

Embodiment 4.
Unless otherwise specified, the second heat exchanger 310 according to the fourth embodiment shown in FIG. 11 has the same configuration as the second heat exchanger 110 according to the first embodiment and exerts the same effects.

11, in the second heat exchanger 310, in at least a portion of the X direction of the distribution pipe 33, the opening area of at least one of the multiple first openings 61 is larger than the opening area of at least one of the multiple second openings 62. From a different perspective, in at least a portion of the X direction of the distribution pipe 33, the inner diameter of at least one of the multiple first openings 61 is larger than the inner diameter of at least one of the multiple second openings 62. For example, in the entire X direction of the distribution pipe 33, the opening area of each of the multiple first openings 61 is larger than the opening area of each of the multiple second openings 62. Note that the opening area of the first opening 61 may be larger than the opening area of the second opening 62 only in a portion of the X direction of the distribution pipe 33.

In the second heat exchanger 310, the flow rate of the two-phase gas-liquid refrigerant distributed from the distribution pipe 33 through the first lower header 31 to each of the multiple first heat transfer tubes 21 can be made greater than the flow rate of the two-phase gas-liquid refrigerant distributed from the distribution pipe 33 through the second lower header 32 to each of the multiple second heat transfer tubes 22. Therefore, compared to a case in which the opening area of each of the multiple first openings 61 is equal to the opening area of each of the multiple second openings 62, the heat load of each of the multiple first heat transfer tubes 21 can be made smaller, and the heat load of each of the first heat transfer tubes 21 and the second heat transfer tubes 22 can be equalized.

As a result, the heat exchange efficiency of the second heat exchanger 310 can be improved compared to when the opening area of each of the multiple first openings 61 is equal to the opening area of each of the multiple second openings 62.

The second heat exchanger 310 according to the fourth embodiment may have a similar configuration to the second heat exchanger 10 according to the first embodiment, except that the opening area of each of the first openings 61 is larger than the opening area of each of the second openings 62.

Although the embodiments of the present disclosure have been described above, the above-described embodiments can be modified in various ways. Furthermore, the scope of the present disclosure is not limited to the above-described embodiments. The scope of the present disclosure is indicated by the claims, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

1 Refrigeration cycle device, 2 Compressor, 3 First heat exchanger, 4 Throttle device, 5 Switching device, 6 First supply section, 7 Second supply section, 10, 110, 210, 310 Second heat exchanger, 11 First inlet/outlet pipe, 12 Second inlet/outlet pipe, 21 First heat transfer tube, 21A Lower end, 22 Second heat transfer tube, 22A Lower end, 30, 130, 230 Lower header, 31 First lower header, 32 Second lower header, 33 Distribution pipe, 33A One end, 33B Other end, 33C First part, 33D Second part, 3 3D1 upper end, 33E outer peripheral surface, 34 first insertion hole, 35 second insertion hole, 36 outer casing member, 36A upper wall portion, 36B lower wall portion, 41 first upper header, 42 second upper header, 43 branch pipe, 50 fin, 51 upstream portion, 52 downstream portion, 53 center portion, 61 first opening, 62 second opening, 361 inner bottom surface, 362 ceiling surface, 3611 first inner bottom surface, 3612 second inner bottom surface, 3613, 3623 concave surface, 3621 first ceiling surface, 3622 second ceiling surface.

Claims (12)

a plurality of first heat transfer tubes extending along a direction of gravity and arranged at intervals in a first direction perpendicular to the direction of gravity;
a plurality of second heat transfer tubes extending along the direction of gravity, arranged at intervals from one another in the first direction, and arranged at intervals from each of the plurality of first heat transfer tubes in a second direction perpendicular to the direction of gravity and the first direction;
a first lower header connected to a lower end of each of the first heat transfer tubes and having a first space formed therein, the first space communicating with an internal space of each of the first heat transfer tubes;
a second lower header connected to a lower end of each of the second heat transfer tubes and having a second space formed therein that communicates with an internal space of each of the second heat transfer tubes;
a distribution pipe connected to each of the first lower header and the second lower header, the distribution pipe having a third space formed therein and communicating with each of the first space and the second space,
The distribution pipe is formed with a plurality of first openings spaced apart from one another in the first direction, and a plurality of second openings spaced apart from one another in the first direction,
A heat exchanger, wherein the third space of the distribution pipe is connected to the first space of the first lower header through the multiple first openings, and is connected to the second space of the second lower header through the multiple second openings. the first lower header and the second lower header are each integrally formed with one another as a part of the lower header,
The heat exchanger according to claim 1 , wherein the distribution pipe is disposed inside the lower header and divides an internal space of the lower header into each of the first space, the second space, and the third space. In a cross section perpendicular to the first direction, the distribution pipe has a first portion and a second portion facing the gravity direction,
The heat exchanger of claim 2 , wherein each of the first and second portions is joined to the lower header. The heat exchanger according to claim 2 or 3, wherein a portion of at least one of the first heat transfer tubes and a portion of at least one of the second heat transfer tubes are in contact with the outer circumferential surface of the distribution tube. the lower header has a first inner bottom surface facing the first space, a second inner bottom surface facing the second space, a first ceiling surface facing the first space and facing the first inner bottom surface, and a second ceiling surface facing the second space and facing the second inner bottom surface,
A heat exchanger as described in any one of claims 2 to 4, wherein inside the lower header, the center of the distribution pipe is located below at least one of a first imaginary straight line passing through a midpoint between the first inner bottom surface and the first ceiling surface and extending along the second direction, and a second imaginary straight line passing through a midpoint between the second inner bottom surface and the second ceiling surface and extending along the second direction. the lower header has a first inner bottom surface facing the first space, a second inner bottom surface facing the second space, a first ceiling surface facing the first space and facing the first inner bottom surface, and a second ceiling surface facing the second space and facing the second inner bottom surface,
A heat exchanger as described in any one of claims 2 to 4, wherein inside the lower header, the center of the distribution pipe is located above at least one of a virtual straight line passing through a midpoint between the first inner bottom surface and the first ceiling surface and extending along the second direction, and a second virtual straight line passing through a midpoint between the second inner bottom surface and the second ceiling surface and extending along the second direction. the lower header has a first inner bottom surface facing the first space, a second inner bottom surface facing the second space, a first ceiling surface facing the first space and facing the first inner bottom surface, and a second ceiling surface facing the second space and facing the second inner bottom surface,
A heat exchanger as described in any one of claims 2 to 4, wherein inside the lower header, the lower end of the distribution pipe is positioned below at least one of the first inner bottom surface and the second inner circumferential surface, and the upper end of the distribution pipe is positioned above at least one of the first ceiling surface and the second ceiling surface. The heat exchanger according to any one of claims 1 to 7, wherein the opening area of at least one of the first openings is greater than the opening area of at least one of the second openings in at least a portion of the distribution pipe in the first direction. Each of the plurality of first openings is disposed above a lower end portion of each of the plurality of first heat transfer tubes,
The heat exchanger according to any one of claims 1 to 8, wherein each of the plurality of second openings is disposed higher than a lower end portion of each of the plurality of second heat transfer tubes. each of the first openings is disposed below a lower end of each of the first heat transfer tubes;
The heat exchanger according to any one of claims 1 to 8, wherein each of the plurality of second openings is disposed below a lower end portion of each of the plurality of second heat transfer tubes. A refrigerant circuit is provided through which the refrigerant circulates.
The refrigerant circuit includes a heat exchanger according to any one of claims 1 to 10,
a refrigeration cycle device, wherein, in a state in which the heat exchanger functions as an evaporator, refrigerant flows into each of the first lower header and the second lower header and is distributed to each of the plurality of first heat transfer tubes and the plurality of second heat transfer tubes. a supply unit that supplies a heat transport medium that exchanges heat with the refrigerant in the heat exchanger to the heat exchanger,
The refrigeration cycle apparatus according to claim 11 , wherein the supply unit forms a flow of the heat transport medium in the second direction from a side of the plurality of first heat transfer tubes toward a side of the plurality of second heat transfer tubes.

Images