heat exchanger

Abstract

To improve evaporation performance of a heat exchanger functioning as an evaporator.SOLUTION: An expansion valve side header 21 of an outdoor heat exchanger 1 is formed with a first flow path 57 through which a refrigerant flows from one end portion 41 side toward the other end portion 42 side, an inflow space 43 adjacent to the one end portion 41 side of the first flow path 57, an inflow port 61 through which the refrigerant flows from the inflow space 43 into the one end portion 41 side of the first flow path 57, and a plurality of insertion spaces 46 that are arranged aligned in a header longitudinal direction 25 and in which one ends of a plurality of heat transfer pipes 23 are disposed respectively. The plurality of insertion spaces 46 include a first one end portion-side insertion space 91 communicated with the inflow space 43 via a first one end portion-side introduction hole 101, and a second one end portion-side insertion space 92 communicated with the first flow path 57 via a second one end portion-side introduction hole 102. The expansion valve side header 21 is formed with a one end-portion-side communication passage 106 that allows the first one end-portion-side insertion space 91 to be communicated with the second one end-portion-side insertion space 92.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a heat exchanger. [Background technology]

[0002] A heat exchanger including a header that distributes gas-liquid two-phase refrigerant to multiple heat transfer tubes is known (Patent Document 1). Inside the header, a circulation flow path is connected to multiple insertion spaces in which one ends of the multiple heat transfer tubes are respectively arranged. The circulation flow path includes a first flow path, a second flow path, a first return flow path that connects the upper end of the first flow path to the upper end of the second flow path, and a second return flow path that connects the lower end of the second flow path to the lower end of the first flow path. The gas-liquid two-phase refrigerant that flows into the header circulates through the circulation flow path, ascending through the first flow path, flowing from the upper end of the first flow path to the upper end of the second flow path via the first return flow path, descending through the second flow path, and flowing from the lower end of the second flow path to the lower end of the first flow path via the second return flow path. Such a heat exchanger can prevent the refrigerant from stagnating in the upper part of the first flow path by circulating the gas-liquid two-phase refrigerant that has flowed into the header through the circulation flow path, and can appropriately divide the gas-liquid two-phase refrigerant into multiple heat transfer tubes so that the flow rates of the refrigerant flowing through each of the multiple heat transfer tubes are equal to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-056544 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such a heat exchanger, when the flow rate of the gas-liquid two-phase refrigerant circulating through the circulation flow path is low, the liquid refrigerant may not rise up the first flow path, resulting in a decrease in the proportion of liquid refrigerant flowing into the upper heat transfer tubes among the plurality of heat transfer tubes. Furthermore, in such a heat exchanger, when the flow rate of the gas-liquid two-phase refrigerant circulating through the circulation flow path is high, the liquid refrigerant may stagnate at the upper end of the first flow path, resulting in an increase in the proportion of liquid refrigerant flowing into the uppermost heat transfer tube among the plurality of heat transfer tubes. When there is a variation in the amount of liquid refrigerant flowing into the plurality of heat transfer tubes, even though the heat exchanger has the capacity to evaporate all of the liquid refrigerant in the gas-liquid two-phase refrigerant, all of the liquid refrigerant evaporates in the heat transfer tubes with a small amount of liquid refrigerant flowing, resulting in an increase in the refrigerant superheat, while all of the liquid refrigerant cannot evaporate in the heat transfer tubes with a large amount of liquid refrigerant flowing, resulting in a decrease in the heat exchange performance of the heat exchanger.

[0005] The disclosed technology has been made in consideration of the above points, and aims to provide a heat exchanger that improves the heat exchange performance of exchanging heat between gas-liquid two-phase refrigerant. [Means for solving the problem]

[0006] A heat exchanger according to one aspect of the present disclosure includes a plurality of heat transfer tubes and a header to which the plurality of heat transfer tubes are joined, the header including a branch flow path for flowing a refrigerant from one end side to the other end side in a longitudinal direction of the header, and a heat exchanger for flowing a refrigerant from the branch flow path to the one end side in the longitudinal direction of the header. be placed an inlet for allowing the refrigerant to flow from the inlet space into one end of the branch flow passage in the longitudinal direction of the header; and a plurality of insertion spaces aligned in the longitudinal direction of the header and in which one ends of the plurality of heat transfer tubes are respectively disposed, the plurality of insertion spaces including a first one-end side insertion space adjacent to the inlet space and a second one-end side insertion space adjacent to the first one-end side insertion space. ,before The first one-end side insertion space and the second one-end side insertion space Unlike and a plurality of inner insertion spaces, the header including: The branch flow path the plurality of inner insert holes In between A plurality of middle introduction holes that communicate with each other; a one-end side communication passage that communicates the first one-end side insertion space with the second one-end side insertion space, and a second one-end side introduction hole that communicates the branch flow path with the second one-end side insertion space, and the header is configured so that the first one-end side introduction hole that communicates the inflow space with the first one-end side insertion space is not formed between the inflow space and the first one-end side insertion space, is formed. [Effects of the Invention]

[0007] The disclosed heat exchanger can improve the heat exchange performance of exchanging heat between gas-liquid two-phase refrigerants. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a refrigerant circuit diagram of an air conditioner provided with a heat exchanger according to a first embodiment. [Figure 2] FIG. 2 is a front view showing the heat exchanger of the first embodiment. [Figure 3] FIG. 3 is a top view showing the heat exchanger of the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of a heat transfer tube of the heat exchanger of the first embodiment. [Figure 5] FIG. 5 is an exploded perspective view showing the internal structure of the expansion valve side header of the heat exchanger of the first embodiment. [Figure 6] FIG. 6 is a schematic vertical cross-sectional view showing an expansion valve side header of the heat exchanger of the first embodiment. [Figure 7] FIG. 7 is a schematic vertical cross-sectional view showing an expansion valve side header of a heat exchanger according to a second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly, liquid refrigerant) flowing into the first one-end side insertion space of the heat exchanger of the second embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly, liquid refrigerant) flowing into the first other-end side insertion space of the heat exchanger of the second embodiment. [Figure 10] FIG. 10 is a schematic vertical cross-sectional view showing an expansion valve side header of a heat exchanger according to a third embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly, liquid refrigerant) flowing into the second one-end side insertion space of the heat exchanger of the third embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly, liquid refrigerant) flowing into the second other-end side insertion space of the heat exchanger of the third embodiment. [Figure 13]FIG. 13 is a cross-sectional view showing a first one-end-side insertion space and a second one-end-side insertion space of a heat exchanger according to a fourth embodiment. [Figure 14] FIG. 14 is a cross-sectional view showing the first other-end-side insertion space and the second other-end-side insertion space of the heat exchanger of the fourth embodiment. [Figure 15] FIG. 15 is a side view showing the expansion valve side header of the heat exchanger of the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a heat exchanger according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the following description does not limit the technology of the present disclosure. In addition, in the following description, the same components are given the same reference numerals, and duplicated descriptions will be omitted. [Example]

[0010] As shown in Fig. 1, the heat exchanger of the first embodiment is an outdoor heat exchanger 1 provided in an air conditioner 10. Fig. 1 is a refrigerant circuit diagram of the air conditioner 10 provided with the outdoor heat exchanger 1 of the first embodiment. The air conditioner 10 includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 is installed outdoors. The indoor unit 3 is installed inside an indoor room.

[0011] The air conditioner 10 includes a refrigerant circuit 4. The refrigerant circuit 4 includes a compressor 5, a four-way valve 6, an indoor heat exchanger 7, an expansion valve 8, and an outdoor heat exchanger 1. The compressor 5 is disposed inside the outdoor unit 2. A suction pipe 11 and a discharge pipe 12 are connected to the compressor 5. The compressor 5 compresses the refrigerant supplied to the suction pipe 11 and discharges the refrigerant into the discharge pipe 12 at a flow rate corresponding to the compressor rotation speed. The flow rate of the refrigerant discharged by the compressor 5 into the discharge pipe 12 per unit time increases as the compressor rotation speed increases.

[0012] The four-way valve 6 is disposed inside the outdoor unit 2. The four-way valve 6 is connected to a suction pipe 11 and a discharge pipe 12, is connected to the outdoor heat exchanger 1 via a refrigerant pipe 14, and is connected to the indoor heat exchanger 7 via a refrigerant pipe 15. The four-way valve 6 switches the refrigerant circuit 4 between a heating cycle and a cooling cycle. When the refrigerant circuit 4 is switched to the heating cycle, the discharge pipe 12 is connected to the indoor heat exchanger 7 via the four-way valve 6, and the suction pipe 11 is connected to the outdoor heat exchanger 1 via the four-way valve 6. When the refrigerant circuit 4 is switched to the cooling cycle, the discharge pipe 12 is connected to the outdoor heat exchanger 1 via the four-way valve 6, and the suction pipe 11 is connected to the indoor heat exchanger 7 via the four-way valve 6.

[0013] The indoor heat exchanger 7 is disposed inside the indoor unit 3. One refrigerant inlet and outlet of the indoor heat exchanger 7 is connected to the expansion valve 8 via refrigerant piping 16, and the other refrigerant inlet and outlet is connected to the four-way valve 6 via refrigerant piping 15 as described above. By rotating a fan (not shown), the indoor unit 3 passes air from the room in which the indoor unit 3 is installed through the indoor heat exchanger 7 to exchange heat with the refrigerant, and blows the air that has exchanged heat with the refrigerant into the room. The expansion valve 8 is disposed inside the outdoor unit 2. The expansion valve 8 is connected to the outdoor heat exchanger 1 via refrigerant piping 17. The air conditioner 10 adjusts the opening of the expansion valve 8 to adjust the amount of refrigerant flowing through the indoor heat exchanger 7 according to the air-conditioning capacity required by the indoor unit 3.

[0014] The outdoor unit 2 is equipped with an outdoor fan 18. The outdoor fan 18 is disposed inside the outdoor unit 2. The outdoor fan 18 blows outdoor air so that the air flows into a ventilation space 19 inside the outdoor unit 2. A ventilation direction 20 in which the air flows due to the outdoor fan 18 is approximately horizontal when the outdoor unit 2 is properly installed. The outdoor heat exchanger 1 is disposed inside the outdoor unit 2 and fixed to the outdoor unit 2 so that the air flowing through the ventilation space 19 passes through the outdoor heat exchanger 1. The outdoor heat exchanger 1 exchanges heat between the refrigerant flowing through the outdoor heat exchanger 1 and the air flowing through the ventilation space 19.

[0015] 2 is a front view showing the outdoor heat exchanger 1 of Example 1. The outdoor heat exchanger 1 includes an expansion valve side header 21 (header), a compressor side header 22, a plurality of heat transfer tubes 23, and a plurality of fins 24. The expansion valve side header 21 is formed in a cylindrical shape, and is disposed so that a header longitudinal direction 25 (longitudinal direction) which is the extension direction of the expansion valve side header 21 is perpendicular to the bottom surface of the outdoor unit 2 (not shown), and is fixed to the outdoor unit 2. A refrigerant pipe 17 is connected to the expansion valve side header 21, and an expansion valve 8 is connected via the refrigerant pipe 17.

[0016] The compressor side header 22 is formed in a columnar shape, is arranged so that the extension direction of the compressor side header 22 is parallel to the header longitudinal direction 25, and is fixed to the outdoor unit 2. A flow dividing space is formed inside the compressor side header 22. The refrigerant piping 14 is connected to the compressor side header 22 so that the four-way valve 6 is connected to the flow dividing space via the refrigerant piping 14.

[0017] 2 and 3 , the plurality of heat transfer tubes 23 are arranged so that a heat transfer tube longitudinal direction 26, which is the extension direction of the heat transfer tubes, is perpendicular to the header longitudinal direction 25, and are lined up at equal intervals in the header longitudinal direction 25. One end of each of the plurality of heat transfer tubes 23 is connected to the expansion valve side header 21. The other end of each of the plurality of heat transfer tubes 23 is connected to the compressor side header 22. The plurality of heat transfer tubes 23 are fixed to the expansion valve side header 21 and the compressor side header 22 by connecting both ends of the plurality of heat transfer tubes 23 to the expansion valve side header 21 and the compressor side header 22, respectively, and the outdoor heat exchanger 1 is fixed to the outdoor unit 2 by the expansion valve side header 21 and the compressor side header 22.

[0018] Each of the fins 24 is formed in a flat plate shape. Fig. 3 is a top view showing the outdoor heat exchanger 1 of the first embodiment. The fins 24 are arranged perpendicular to the heat transfer tube longitudinal direction 26 (parallel to the ventilation direction 20) and are aligned at equal intervals in the heat transfer tube longitudinal direction 26. The fins 24 are fixed to the heat transfer tubes 23 so as to be thermally connected to them.

[0019] Each of the plurality of heat transfer tubes 23 is formed in a flat shape, as shown in Fig. 4. Fig. 4 is a cross-sectional view of the heat transfer tube 23 of the outdoor heat exchanger 1 of the first embodiment. A plurality of flow paths 33 are formed inside the heat transfer tube 23 and aligned in the ventilation direction 20. The other ends of the plurality of heat transfer tubes 23 are connected to the compressor-side header 22, so that the plurality of flow paths 33 are connected to the flow branch space of the compressor-side header 22.

[0020] 5 is an exploded perspective view showing the internal structure of the expansion valve side header 21 of the outdoor heat exchanger 1 of the first embodiment. The expansion valve side header 21 includes a plurality of plate-like members 71 to 76 that are all rectangular in shape. The plurality of plate-like members 71 to 76 are stacked and joined to one another, with the stacking direction being approximately parallel to the heat transfer tube longitudinal direction 26. The plurality of plate-like members 71 to 76 include a refrigerant piping side plate-like member 71, a heat transfer tube side plate-like member 72, a plurality of circulation flow path plate-like members 73, a plurality of return flow path plate-like members 74, a plurality of insertion space plate-like members 75, and an introduction hole plate-like member 76. 5, the plate-like members are stacked in the following order from upstream to downstream in the introduction direction 48 (the direction in which refrigerant flows in the outdoor heat exchanger 1 when the outdoor heat exchanger 1 functions as an evaporator): refrigerant piping side plate-like member 71, multiple return flow path plate-like members 74, multiple circulation flow path plate-like members 73, introduction hole plate-like member 76, multiple insertion space plate-like members 75, and heat transfer tube side plate-like member 72. In the following description, when referring to the multiple return flow path plate-like members 74, the multiple circulation flow path plate-like members 73, and the multiple insertion space plate-like members 75 formed by the multiple plate-like members 71 to 76, the word "multiple" may be omitted when referring to a combination of the multiple plate-like members 71 to 76 joined together.

[0021] The circulation flow path plate-shaped members 73 are formed to have the same shape (in this Example 1, the three circulation flow path plate-shaped members 73 shown in FIG. 5 have the same shape). The return flow path plate-shaped member 74 is disposed between the circulation flow path plate-shaped member 73 and the refrigerant pipe side plate-shaped member 71. The insertion space plate-shaped members 75 are formed to have the same shape (in this Example 1, the three insertion space plate-shaped members 75 shown in FIG. 5 have the same shape). The insertion space plate-shaped member 75 is disposed between the introduction hole plate-shaped member 76 and the heat transfer tube side plate-shaped member 72. The introduction hole plate-shaped member 76 is disposed between the circulation flow path plate-shaped member 73 and the insertion space plate-shaped member 75.

[0022] In the following description, the end face of the lower end of the expansion valve side header 21 in the header longitudinal direction 25 will be referred to as one end 41, and the end face of the upper end of the expansion valve side header 21 opposite the one end 41 will be referred to as the other end 42.

[0023] The expansion valve-side header 21 is formed by stacking the above-described plate-like members in the order of refrigerant pipe-side plate-like member 71, return flow path plate-like member 74, circulation flow path plate-like member 73, introduction hole plate-like member 76, insertion space plate-like member 75, and heat transfer tube-side plate-like member 72 from upstream to downstream in the introduction direction 48, thereby forming an inflow space 43, a refrigerant pipe through-hole 44, a circulation flow path 45 (branch flow path), an inflow port 61, a plurality of insertion spaces 46, a plurality of heat transfer tube through-holes 47, and a plurality of introduction holes 62 inside the expansion valve-side header 21. The inflow space 43 is located in a region close to one end 41 inside the expansion valve-side header 21. The inflow space 43 is formed from inflow space holes 83 formed in each circulation flow path plate-like member 73.

[0024] The refrigerant piping through-hole 44 is formed by a refrigerant piping hole 77 formed in the refrigerant piping side plate-like member 71 and a refrigerant piping hole 78 formed in the return flow path plate-like member 74. Therefore, the refrigerant piping through-hole 44 is disposed on the upstream side of the inflow space 43 in the introducing direction 48. The refrigerant piping 17 passes through the refrigerant piping through-hole 44, and the inflow space 43 is connected to the expansion valve 8 via the refrigerant piping 17.

[0025] The circulation flow path 45 is formed by a circulation flow path plate-shaped member 73 and a turn-back flow path plate-shaped member 74, and includes a first flow path 57, a second flow path 58, a first turn-back flow path 51, and a second turn-back flow path 52. The first flow path 57 is formed from first flow path holes 84 formed in a plurality of circulation flow path plate-shaped members 73. The second flow path 58 is formed from second flow path holes 85 formed in a plurality of circulation flow path plate-shaped members 73. Therefore, the first flow path 57 and the second flow path 58 are aligned with the inflow space 43 in the header longitudinal direction 25 and are located above the inflow space 43. The first flow path 57 is formed along a straight line parallel to the header longitudinal direction 25. The second flow path 58 is located upwind of the first flow path 57 in the ventilation direction 20 and is formed along another straight line parallel to the header longitudinal direction 25.

[0026] The first turn flow path 51 is formed by first turn flow path holes 81 formed in the plurality of turn flow path plate-shaped members 74, and turns the refrigerant flowing through the first flow path 57 back to the second flow path 58. That is, the direction in which the refrigerant flows through the first turn flow path 51 is perpendicular to the introduction direction 48 and parallel to the ventilation direction 20. The second turn flow path 52 is formed by second turn flow path holes 82 formed in the plurality of turn flow path plate-shaped members 74, and turns the refrigerant flowing through the second flow path 58 back to the first flow path 57. That is, the direction in which the refrigerant flows through the second turn flow path 52 is perpendicular to the introduction direction 48 and parallel to the ventilation direction 20. Therefore, the first turn flow path 51 and the second turn flow path 52 are aligned in the header longitudinal direction 25 and are disposed upstream of the first flow path 57 and the second flow path 58 in the introduction direction 48. The first turning flow path 51 is formed in a region close to the other end 42, and is connected to the upper end of the first flow path 57 and the upper end of the second flow path 58. The second turning flow path 52 is formed in a lower region close to the one end 41, and is connected to the lower end of the first flow path 57 and the lower end of the second flow path 58.

[0027] The inlet 61 is formed from an inlet hole 86 formed in the plurality of circulation flow path plate-shaped members 73. Therefore, the inlet 61 is disposed between the inflow space 43 and the first flow path 57, and the refrigerant that has flowed into the inlet 61 flows into the first flow path 57 via the inlet 61.

[0028] The multiple insertion spaces 46 are formed by communicating multiple insertion space holes 87 formed in the multiple insertion space plate-shaped members 75. Therefore, the multiple insertion spaces 46 are arranged downstream in the introduction direction 48 as seen from the area where the inflow space 43 and the circulation flow path 45 are arranged, and are lined up in the header longitudinal direction 25. The multiple insertion spaces 46 have approximately the same volume.

[0029] The multiple introduction holes 62 are formed in the introduction hole plate member 76. Therefore, the multiple introduction holes 62 are aligned in the header longitudinal direction 25 and are disposed between the first flow passage 57 and the multiple insertion spaces 46, respectively.

[0030] The heat transfer tube through holes 47 are formed in the heat transfer tube side plate member 72. Therefore, the heat transfer tube through holes 47 are arranged downstream in the introduction direction 48 as seen from the insertion spaces 46, and are aligned at equal intervals in the header longitudinal direction 25. The insertion spaces 46 are connected to the heat transfer tubes 23 via the heat transfer tube through holes 47, respectively.

[0031] The surfaces of the plurality of plate-like members 71-76 are coated with brazing material, and the plate-like members are stacked and heated in a furnace, melting the brazing material and bonding them together to form the expansion valve side header 21. Because the expansion valve side header 21 is formed by stacking the plurality of plate-like members 71-76 with their outer peripheries aligned, the strength and durability of the expansion valve side header 21 can be improved compared to, for example, a box-shaped header formed by combining plate-like members and U-shaped members. Furthermore, because the expansion valve side header 21 is formed by stacking the plurality of plate-like members 71-76, changes to the refrigerant flow path in the expansion valve side header 21 or the number of heat transfer tubes 23 to be joined can be accommodated by simply changing one of the plate-like members. This improves the design flexibility of the outdoor heat exchanger 1, including the expansion valve side header 21, and reduces development and manufacturing costs.

[0032] The plurality of heat transfer tubes 23 pass through the plurality of heat transfer tube through-holes 47 respectively and are joined to the expansion valve side header 21 .

[0033] FIG. 6 is a schematic vertical cross-sectional view showing the expansion valve-side header 21. The multiple insertion spaces 46 include a first one-end-side insertion space 91, a second one-end-side insertion space 92, a first other-end-side insertion space 93, a second other-end-side insertion space 94, and multiple middle insertion spaces 95. The first one-end-side insertion space 91 is the insertion space located closest to the one end 41 among the multiple insertion spaces 46 and is located downstream of the inflow space 43 in the introduction direction 48. The second one-end-side insertion space 92 is the insertion space located adjacent to the first one-end-side insertion space 91 above the header longitudinal direction 25 among the multiple insertion spaces 46. That is, the second one-end-side insertion space 92 is located downstream of a lower end region 96 of the first flow path 57 below the header longitudinal direction 25 in the introduction direction 48. The lower end region 96 is the region of the first flow path 57 upstream of the second one-end-side insertion space 92 in the introduction direction 48. The first other-end side insertion space 93 is the insertion space that is located closest to the other end 42 among the multiple insertion spaces 46. That is, the first other-end side insertion space 93 is located downstream in the introduction direction 48 of an upper end region 97 of the first flow path 57 that is below the header longitudinal direction 25. The second other-end side insertion space 94 is located downstream in the introduction direction 48 of the upper end region 97 and is the insertion space that is located next to the first other-end side insertion space 93 among the multiple insertion spaces 46 on the lower side in the header longitudinal direction 25. The upper end region 97 is the region upstream in the introduction direction 48 of the first other-end side insertion space 93 and the second other-end side insertion space 94 of the first flow path 57.

[0034] The multiple introduction holes 62 include a first one-end introduction hole 101, a second one-end introduction hole 102, a first other-end introduction hole 103, a second other-end introduction hole 104, and multiple middle introduction holes 105. The first one-end introduction hole 101 is the introduction hole of the multiple introduction holes 62 that is located closest to the one end 41, and communicates between the inflow space 43 and the first one-end insertion space 91. The first one-end insertion space 91 is connected to the inflow space 43 via the first one-end introduction hole 101. The second one-end introduction hole 102 is the introduction hole of the multiple introduction holes 62 that is located adjacent to the first one-end introduction hole 101 on the upper side in the header longitudinal direction 25, and communicates between a lower end region 96 of the first flow path 57 and the second one-end insertion space 92. The second one-end side insertion space 92 is connected to a lower end region 96 of the first flow path 57 via a second one-end side introduction hole 102. The first other-end side introduction hole 103 is an introduction hole of the multiple introduction holes 62 that is located closest to the other end 42 and communicates between an upper end region 97 of the first flow path 57 and the first other-end side insertion space 93. The first other-end side insertion space 93 is connected to the upper end region 97 of the first flow path 57 via the first other-end side introduction hole 103. The second other-end side introduction hole 104 is an introduction hole of the multiple introduction holes 62 that is located adjacent to the first other-end side introduction hole 103 on the lower side in the header longitudinal direction 25 and communicates between the upper end region 97 of the first flow path 57 and the second other-end side insertion space 94. The second other-end side insertion space 94 is connected to the upper end region 97 of the first flow path 57 via the second other-end side introduction hole 104. The plurality of middle introduction holes 105 are introduction holes different from the first one-end side introduction hole 101, the second one-end side introduction hole 102, the first other-end side introduction hole 103, and the second other-end side introduction hole 104 among the plurality of introduction holes 62, and are formed between the second one-end side introduction hole 102 and the second other-end side introduction hole 104, and communicate between the first flow path 57 and the plurality of middle insertion spaces 95. The plurality of middle insertion spaces 95 are connected to the first flow path 57 via the plurality of middle introduction holes 105, respectively.

[0035] The expansion valve side header 21 is further formed with a one-end side communication passage 106 and an other-end side communication passage 107. The one-end side communication passage 106 communicates between the first one-end side insertion space 91 and the second one-end side insertion space 92 and is formed in a partition 108 that separates the first one-end side insertion space 91 and the second one-end side insertion space 92. The second one-end side insertion space 92 is connected to the first one-end side insertion space 91 via the one-end side communication passage 106. The other-end side communication passage 107 communicates between the first other-end side insertion space 93 and the second other-end side insertion space 94 and is formed in a partition 109 that separates the first other-end side insertion space 93 and the second other-end side insertion space 94. The second other-end side insertion space 94 is connected to the first other-end side insertion space 93 via the other-end side communication passage 107. That is, some of the multiple insertion space plate-like members 75 further have a notch for a one end side communicating passage and a notch for an other end side communicating passage that respectively form a one end side communicating passage 106 and an other end side communicating passage 107 when the multiple plate-like members 71 to 76 are stacked.

[0036] The air conditioner 10 can perform heating and cooling operations as described below. [Heating operation] The heating operation is performed, for example, when the air conditioner 10 is operated by a user to perform the heating operation. When the air conditioner 10 performs the heating operation, the four-way valve 6 switches the refrigerant circuit 4 to the heating cycle. The compressor 5 compresses the low-pressure gas-phase refrigerant that flows from the four-way valve 6 into the suction pipe 11. The low-pressure gas-phase refrigerant is compressed by the compressor 5 to become high-pressure gas-phase refrigerant. The compressor 5 discharges the high-pressure gas-phase refrigerant into the discharge pipe 12. The high-pressure gas-phase refrigerant discharged into the discharge pipe 12 flows into the indoor heat exchanger 7 via the four-way valve 6 because the refrigerant circuit 4 has been switched to the heating cycle.

[0037] The indoor unit 3 passes air from the room in which the indoor unit 3 is installed through the indoor heat exchanger 7. The indoor heat exchanger 7 exchanges heat between the high-pressure gas-phase refrigerant that has flowed into the indoor heat exchanger 7 and the air passing through the indoor heat exchanger 7, cooling the high-pressure gas-phase refrigerant that has flowed into the indoor heat exchanger 7 and heating the air passing through the indoor heat exchanger 7. The indoor unit 3 blows the air heated by the indoor heat exchanger 7 into the room in which the indoor unit 3 is installed, heating the room. The high-pressure gas-phase refrigerant is cooled and condensed in the indoor heat exchanger 7, becoming a supercooled high-pressure liquid-phase refrigerant. In other words, the indoor heat exchanger 7 functions as a condenser when the air conditioner 10 performs heating operation. The high-pressure liquid-phase refrigerant flows out of the indoor heat exchanger 7 and flows into the expansion valve 8.

[0038] Expansion valve 8 reduces the pressure of the high-pressure liquid-phase refrigerant that has flowed into expansion valve 8. The high-pressure liquid-phase refrigerant is reduced in pressure by expansion valve 8 and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows out of expansion valve 8 and flows into refrigerant piping 17. Outdoor fan 18 flows outdoor air into ventilation space 19.

[0039] The low-pressure gas-liquid two-phase refrigerant that has flowed into the refrigerant pipe 17 flows into the inlet space 43 of the expansion valve-side header 21 through the refrigerant pipe through-hole 44. The low-pressure gas-liquid two-phase refrigerant that has flowed into the inlet space 43 flows into the lower end region 96 on the one end 41 side of the first flow path 57 through the inlet 61. The low-pressure gas-liquid two-phase refrigerant that has flowed into the lower end region 96 through the inlet 61 becomes a jet flow that flows toward the other end 42 and rises along the first flow path 57. The low-pressure gas-liquid two-phase refrigerant that has risen along the first flow path 57 reaches the upper end region 97 on the other end 42 side of the first flow path 57 and flows into the second flow path 58 through the first return flow path 51. The low-pressure gas-liquid two-phase refrigerant that has flowed into the second flow path 58 through the first return flow path 51 descends along the second flow path 58.

[0040] The low-pressure gas-liquid two-phase refrigerant that has descended along the second flow path 58 flows into the lower end region 96 of the first flow path 57 via the second turning flow path 52. The low-pressure gas-liquid two-phase refrigerant that has flowed into the lower end region 96 via the second turning flow path 52 is pushed up by the jet of low-pressure gas-liquid two-phase refrigerant that has flowed into the lower end region 96 via the inlet 61, and rises along the first flow path 57 together with the low-pressure gas-liquid two-phase refrigerant that has flowed into the lower end region 96 via the inlet 61. That is, during heating operation, the low-pressure gas-liquid two-phase refrigerant that has flowed into the circulation flow path 45 circulates through the circulation flow path 45.

[0041] The low-pressure gas-liquid two-phase refrigerant that has flowed into the inflow space 43 further flows into the first one-end side insertion space 91 via the first one-end side introduction hole 101. The low-pressure gas-liquid two-phase refrigerant rising along the first flow path 57 flows into a plurality of insertion spaces other than the first one-end side insertion space 91 among the plurality of insertion spaces 46 via a plurality of introduction holes other than the first one-end side introduction hole 101 among the plurality of introduction holes 62. That is, the low-pressure gas-liquid two-phase refrigerant flowing through the lower end region 96 of the first flow path 57 flows into the second one-end side insertion space 92 via the second one-end side introduction hole 102. The low-pressure gas-liquid two-phase refrigerant rising along the first flow path 57 flows into the plurality of middle insertion spaces 95 via the plurality of middle introduction holes 105. The low-pressure gas-liquid two-phase refrigerant flowing through the upper end region 97 of the first flow path 57 flows into the second other end side insertion space 94 through the second other end side inlet hole 104, and flows into the first other end side insertion space 93 through the first other end side inlet hole 103.

[0042] The low-pressure gas-liquid two-phase refrigerant that has flowed into the multiple insertion spaces 46 flows into the multiple heat transfer tubes 23 and flows through the multiple flow paths 33 formed inside the multiple heat transfer tubes 23. The low-pressure gas-liquid two-phase refrigerant that has flowed into the multiple heat transfer tubes 23 exchanges heat with the air flowing through the ventilation space 19, is heated and evaporates, becomes low-pressure gas-phase refrigerant, and flows out of the multiple heat transfer tubes 23. In other words, the outdoor heat exchanger 1 functions as an evaporator when the air conditioner 10 performs heating operation.

[0043] The low-pressure gas-phase refrigerant flowing out from the heat transfer tubes 23 join together in the compressor-side header 22 and flows out from the compressor-side header 22. The low-pressure gas-phase refrigerant flowing out from the compressor-side header 22 flows into the four-way valve 6 via the refrigerant piping 14, and flows into the suction pipe 11 of the compressor 5 via the four-way valve 6 because the refrigerant circuit 4 is switched to the heating cycle.

[0044] Regardless of whether the amount of refrigerant circulating through the refrigerant circuit 4 is small or large, all of the refrigerant flows into the inflow space 43, causing liquid refrigerant to stagnate. When liquid refrigerant stagnates in the inflow space 43, the flow rate of the liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the first one-end side insertion space 91 via the first one-end side introduction hole 101 may be greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. The outdoor heat exchanger 1 is provided with the one-end side communicating passage 106, so that a portion of the flow rate of the liquid refrigerant flowing into the first one-end side insertion space 91 can be discharged into the second one-end side insertion space 92 via the one-end side communicating passage 106. Therefore, the outdoor heat exchanger 1 can make the flow rate of liquid refrigerant flowing from the first one-end side insertion space 91 into the heat transfer tube inserted into the first one-end side insertion space 91 among the multiple heat transfer tubes 23 closer to the flow rate of liquid refrigerant flowing into the other heat transfer tubes, thereby suppressing refrigerant bias toward the multiple heat transfer tubes 23.

[0045] When the low-pressure gas-liquid two-phase refrigerant rises along the first flow path 57, the gas refrigerant in the low-pressure gas-liquid two-phase refrigerant rises through the center of the first flow path 57, and the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant is forced toward the inner wall surface of the first flow path 57 by the gas refrigerant rising through the center of the first flow path 57. For example, if the cross section of the first flow path 57 is rectangular, the liquid refrigerant is forced toward the four corners of the first flow path 57. When the amount of refrigerant circulating through the refrigerant circuit 4 is high, the liquid refrigerant forced toward the four corners is forced by the gas refrigerant rising through the center of the first flow path 57 and rises along the inner wall surface of the first flow path 57. Because the liquid refrigerant rises along the inner wall surface of the first flow path 57, it is difficult for the liquid refrigerant to flow into the insertion spaces 46 through the introduction holes 62, and the liquid refrigerant may stagnate in an upper end region 97 of the first flow path 57. When liquid refrigerant accumulates in the upper end region 97 of the first flow path 57, the flow rate of the liquid refrigerant of the low-pressure gas-liquid two-phase refrigerant flowing into the first other-end side insertion space 93 via the first other-end side inlet hole 103 may be greater than the flow rate of the liquid refrigerant flowing from the first flow path 57 into the plurality of middle insertion spaces 95. The outdoor heat exchanger 1, by forming the other-end side communicating passage 107, can cause a portion of the liquid refrigerant flowing into the first other-end side insertion space 93 to flow out to the second other-end side insertion space 94 via the other-end side communicating passage 107. Therefore, the outdoor heat exchanger 1 can make the flow rate of the liquid refrigerant flowing through the heat transfer tube inserted into the first other-end side insertion space 93 of the plurality of heat transfer tubes 23 closer to the flow rate of the liquid refrigerant flowing through the other heat transfer tubes, thereby suppressing refrigerant drift toward the plurality of heat transfer tubes 23.

[0046] [Cooling operation] When the air conditioner 10 is operated by a user to perform cooling operation, the four-way valve 6 is switched so that the refrigerant circuit 4 is in the cooling cycle. The compressor 5 compresses the low-pressure gas-phase refrigerant drawn in from the four-way valve 6 through the suction pipe 11. The low-pressure gas-phase refrigerant is compressed by the compressor 5 to become high-pressure gas-phase refrigerant, which is then discharged to the discharge pipe 12. Because the refrigerant circuit 4 has been switched to the cooling cycle, the high-pressure gas-phase refrigerant discharged to the discharge pipe 12 flows into the outdoor heat exchanger 1 via the four-way valve 6 and the refrigerant piping 14.

[0047] The high-pressure gas-phase refrigerant that flows into the outdoor heat exchanger 1 flows into the compressor-side header 22 and is diverted to the multiple heat transfer tubes 23. The high-pressure gas-phase refrigerant diverted to the multiple heat transfer tubes 23 exchanges heat with the air flowing through the ventilation space 19 due to the rotation of the outdoor fan 18, condensing to become a supercooled high-pressure liquid-phase refrigerant. In other words, the outdoor heat exchanger 1 functions as a condenser when the air conditioner 10 performs cooling operation. The high-pressure liquid-phase refrigerant flows out of the multiple heat transfer tubes 23 and into the multiple insertion spaces 46 of the expansion valve-side header 21. The high-pressure liquid-phase refrigerant that flows into an insertion space other than the first one-end side insertion space 91 of the multiple insertion spaces 46 flows into the first flow path 57 of the circulation flow path 45 through the multiple introduction holes 62 and merges there. The high-pressure liquid-phase refrigerant that has merged in the first flow path 57 flows into the inlet space 43 through the inlet 61. The high-pressure liquid-phase refrigerant that has flowed into the first one-end side insertion space 91 flows into the inflow space 43 through the first one-end side introduction hole 101, and merges in the inflow space 43 with the high-pressure liquid-phase refrigerant that has flowed into the inflow space 43 through the inflow port 61. The high-pressure liquid-phase refrigerant that has merged in the inflow space 43 flows into the refrigerant pipe 17 through the refrigerant piping through-hole 44, flows through the refrigerant pipe 17, and flows into the expansion valve 8.

[0048] Refrigerating machine oil contained in the high-pressure liquid-phase refrigerant flowing through the first flow path 57 descends due to gravity and accumulates in a lower end region 96 of the first flow path 57. The refrigerating machine oil accumulated in the lower end region 96 of the first flow path 57 flows into the inlet space 43 together with the high-pressure liquid-phase refrigerant through the inlet 61. The refrigerating machine oil accumulated in the inlet space 43 flows out of the outdoor heat exchanger 1 together with the high-pressure liquid-phase refrigerant through the refrigerant piping 17. Therefore, when the outdoor heat exchanger 1 functions as a condenser, the refrigerating machine oil contained in the high-pressure liquid-phase refrigerant can be caused to flow out of the outdoor heat exchanger 1 through the refrigerant piping 17, thereby preventing the refrigerating machine oil from accumulating in the outdoor heat exchanger 1.

[0049] The high-pressure liquid-phase refrigerant that flows into the expansion valve 8 is decompressed to become a low-pressure two-phase gas-liquid refrigerant, which then flows out of the expansion valve 8, flows through the refrigerant pipe 16, and flows into the indoor heat exchanger 7. The low-pressure two-phase gas-liquid refrigerant that flows into the indoor heat exchanger 7 exchanges heat with room air drawn into the indoor unit 3 by the rotation of the indoor fan (not shown). As a result, the air passing through the indoor heat exchanger 7 is cooled by the low-pressure two-phase gas-liquid refrigerant that flows into the indoor heat exchanger 7, and the cooled air is blown into the room where the indoor unit 3 is installed, thereby cooling the room. Meanwhile, the low-pressure two-phase gas-liquid refrigerant that flows into the indoor heat exchanger 7 is heated and evaporated in the indoor heat exchanger 7 to become a low-pressure gas-phase refrigerant. In other words, the indoor heat exchanger 7 functions as an evaporator when the air conditioner 10 performs cooling operation. The low-pressure gas-phase refrigerant that flows out of the indoor heat exchanger 7 flows sequentially through the refrigerant pipe 15, the four-way valve 6, and the suction pipe 11, and is drawn into the compressor 5 where it is compressed again.

[0050] [Effects of the heat exchanger of Example 1] The heat exchanger of the first embodiment includes a plurality of heat transfer tubes 23 and an expansion valve side header 21 to which the plurality of heat transfer tubes 23 are joined. The expansion valve side header 21 is formed with a first flow path 57, an inflow space 43, an inlet 61, and a plurality of insertion spaces 46. The first flow path 57 allows refrigerant to flow from one end 41 toward the other end 42 in the header longitudinal direction 25. The inflow space 43 is adjacent to the one end 41 of the first flow path 57. The inlet 61 allows refrigerant to flow from the inflow space 43 to the one end 41 of the first flow path 57. The plurality of insertion spaces 46 are aligned in the header longitudinal direction 25, and one ends of the plurality of heat transfer tubes 23 are respectively disposed therein. The plurality of insertion spaces 46 includes a first one-end side insertion space 91, a second one-end side insertion space 92, a first other-end side insertion space 93, a second other-end side insertion space 94, and a plurality of middle insertion spaces 95. The first one-end side insertion space 91 is arranged closest to the one end 41 and adjacent to the inflow space 43. The second one-end side insertion space 92 is adjacent to the first one-end side insertion space 91. The first other-end side insertion space 93 is arranged closest to the other end 42. The second other-end side insertion space 94 is adjacent to the first other-end side insertion space 93. The multiple middle insertion spaces 95 are insertion spaces that are different from the first one-end side insertion space 91, the second one-end side insertion space 92, the first other-end side insertion space 93, and the second other-end side insertion space 94 among the multiple insertion spaces 46.

[0051] The expansion valve side header 21 is formed with a one-end side communication passage 106, an other-end side communication passage 107, a first one-end side introduction hole 101, a second one-end side introduction hole 102, a first other-end side introduction hole 103, a second other-end side introduction hole 104, and a plurality of middle side introduction holes 105. The one-end side communication passage 106 connects the first one-end side insertion space 91 and the second one-end side insertion space 92. The other-end side communication passage 107 connects the first other-end side insertion space 93 and the second other-end side insertion space 94. The first one-end side introduction hole 101 connects the inflow space 43 and the first one-end side insertion space 91. The second one-end side introduction hole 102 connects the first flow path 57 and the second one-end side insertion space 92. The first other-end side introduction hole 103 communicates the first flow path 57 with the first other-end side insertion space 93. The second other-end side introduction hole 104 communicates the first flow path 57 with the second other-end side insertion space 94. The multiple middle introduction holes 105 communicate the multiple middle insertion spaces 95 with the first flow path 57, respectively.

[0052] In this case, even when liquid refrigerant accumulates in the inflow space 43, the heat exchanger of Example 1 can cause the liquid refrigerant that flows from the inflow space 43 into the first one-end side insertion space 91 through the first one-end side introduction hole 101 to flow into the second one-end side insertion space 92 through the one-end side communicating passage 106. Therefore, the heat exchanger of Example 1 can suppress uneven flow in which more liquid refrigerant flows through one of the heat transfer tubes 23 that is inserted into the first one-end side insertion space 91 than through the other heat transfer tubes. Furthermore, even when liquid refrigerant accumulates in the upper end region 97 of the first flow path 57, the heat exchanger of Example 1 can cause the liquid refrigerant that flows from the upper end region 97 into the first other-end side insertion space 93 through the first other-end side introduction hole 103 to flow into the second other-end side insertion space 94 through the other-end side communicating passage 107. Therefore, the heat exchanger of the first embodiment can suppress uneven flow of liquid refrigerant in the heat transfer tube inserted into the first other-end side insertion space 93 among the plurality of heat transfer tubes 23 compared to the other heat transfer tubes.

[0053] Incidentally, the heat exchanger of the first embodiment described above has both the first one-end side inlet 101 and the second one-end side inlet 102, but it is also possible for one of the first one-end side inlet 101 and the second one-end side inlet 102 to be formed without the other. Furthermore, the heat exchanger of the first embodiment described above has both the first other-end side inlet 103 and the second other-end side inlet 104, but it is also possible for one of the first other-end side inlet 103 and the second other-end side inlet 104 to be formed without the other. [Example]

[0054] 7 is a schematic vertical cross-sectional view showing an expansion valve side header 111 of a heat exchanger of Example 2. The expansion valve side header 111 of the heat exchanger of Example 2 is different from the expansion valve side header 21 of the heat exchanger of Example 1 described above in that the second one-end side introduction hole 102 and the second other-end side introduction hole 104 are not formed, and other parts are the same as the expansion valve side header 21 described above. That is, the expansion valve side header 111 is formed so that no introduction hole connecting the second one-end side insertion space 92 and the first flow path 57 is formed in the introduction hole plate member 76, and no introduction hole connecting the second other-end side insertion space 94 and the first flow path 57 is formed in the introduction hole plate member 76.

[0055] When the heat exchanger of the second embodiment functions as an evaporator, liquid refrigerant accumulates in the inflow space 43, regardless of whether the amount of refrigerant circulating in the refrigerant circuit 4 is small or large, as in the heat exchanger of the first embodiment described above. When liquid refrigerant accumulates in the inflow space 43, the flow rate of the liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the first one-end side insertion space 91 through the first one-end side introduction hole 101 is larger than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. FIG. 8 is a cross-sectional view showing the flow of the low-pressure gas-liquid two-phase refrigerant (particularly the liquid refrigerant) flowing into the first one-end side insertion space 91 of the heat exchanger of the second embodiment. As shown in FIG. 8, the heat exchanger of the second embodiment is provided with the one-end side communicating passage 106, so that a portion of the liquid refrigerant flowing into the first one-end side insertion space 91 can flow out to the second one-end side insertion space 92 through the one-end side communicating passage 106. Therefore, in the heat exchanger of Example 2, the flow rate of liquid refrigerant flowing into the heat transfer tube inserted into the first one-end side insertion space 91 among the multiple heat transfer tubes 23 can be made closer to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into the multiple middle insertion spaces 95, and the uneven flow of refrigerant into the multiple heat transfer tubes 23 can be suppressed.

[0056] In the heat exchanger of the first embodiment described above, low-pressure gas-liquid two-phase refrigerant may flow into the second one-end side insertion space 92 through both the second one-end side introduction hole 102 and the one-end side communicating passage 106, and the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the second one-end side insertion space 92 may be greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. In the heat exchanger of the second embodiment, the second one-end side introduction hole 102 is not formed, and therefore the flow rate of the liquid refrigerant flowing into the second one-end side insertion space 92 can be reduced. Therefore, the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the second one-end side insertion space 92 can be made closer to the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. Furthermore, the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the second one-end side insertion space 92 can be made closer to the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the middle insertion spaces 95. Therefore, the heat exchanger of the second embodiment can suppress uneven flow of the refrigerant into the heat transfer tubes 23.

[0057] As in the heat exchanger of the first embodiment described above, liquid refrigerant may accumulate in the upper end region 97 of the first flow path 57 of the heat exchanger of the second embodiment when a large amount of refrigerant circulates through the refrigerant circuit 4. When liquid refrigerant accumulates in the upper end region 97, the flow rate of the liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the first other-end side insertion space 93 through the first other-end side inlet 103 is greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95 from the first flow path 57. FIG. 9 is a cross-sectional view showing the flow of the low-pressure gas-liquid two-phase refrigerant (particularly the liquid refrigerant) flowing into the first other-end side insertion space 93 of the heat exchanger of the second embodiment. As shown in FIG. 9, the heat exchanger of the second embodiment has the other-end side communicating passage 107 formed therein, so that a portion of the liquid refrigerant flowing into the first other-end side insertion space 93 through the first other-end side inlet 103 can flow out into the second other-end side insertion space 94. Therefore, in the heat exchanger of Example 2, the flow rate of liquid refrigerant flowing into the heat transfer tube inserted into the first other-end side insertion space 93 among the multiple heat transfer tubes 23 can be made closer to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into the multiple middle insertion spaces 95, and the uneven flow of refrigerant into the multiple heat transfer tubes 23 can be suppressed.

[0058] In the heat exchanger of the first embodiment described above, low-pressure gas-liquid two-phase refrigerant may flow into the second other-end side insertion space 94 via both the second other-end side inlet hole 104 and the other-end side communicating passage 107, and the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the second other-end side insertion space 94 may be greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. In the heat exchanger of the second embodiment, the second other-end side inlet hole 104 is not formed, and therefore the flow rate of the liquid refrigerant flowing into the second other-end side insertion space 94 can be reduced and the flow rate of the liquid refrigerant flowing into the second other-end side insertion space 94 can be made closer to the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. Therefore, in the heat exchanger of the second embodiment, the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the second one-end side insertion space 92 can be made close to the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the plurality of middle insertion spaces 95. Therefore, the heat exchanger of the second embodiment can suppress uneven flow of the refrigerant into the plurality of heat transfer tubes 23. [Example]

[0059] 10 is a schematic vertical cross-sectional view showing an expansion valve side header 112 of a heat exchanger of Example 3. The expansion valve side header 112 of the heat exchanger of Example 3 is different from the expansion valve side header 21 of the heat exchanger of Example 1 described above in that the first one-end side introduction hole 101 and the first other-end side introduction hole 103 are not formed, and other parts are the same as the expansion valve side header 21 described above. That is, the expansion valve side header 112 is formed so that no introduction hole connecting the first one-end side insertion space 91 and the inflow space 43 is formed in the introduction hole plate member 76, and no introduction hole connecting the first other-end side insertion space 93 and the first flow path 57 is formed in the introduction hole plate member 76.

[0060] When the heat exchanger of the third embodiment functions as an evaporator, the flow velocity of the gas-liquid two-phase refrigerant flowing from the inlet space 43 into the first flow path 57 through the inlet 61 is slow when the amount of refrigerant circulating through the refrigerant circuit 4 is low. Therefore, in the heat exchanger of the third embodiment, the flow velocity of the low-pressure gas-liquid two-phase refrigerant ascending through the first flow path 57 is slow. When the flow velocity of the low-pressure gas-liquid two-phase refrigerant ascending through the first flow path 57 is slow, the liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant ascending through the first flow path 57 may accumulate in the lower end region 96 of the first flow path 57 due to gravity. When the liquid refrigerant accumulates in the lower end region 96, the flow rate of the liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the second one-end side insertion space 92 through the second one-end side introduction hole 102 may be greater than the flow rate of the liquid refrigerant flowing from the first flow path 57 into the plurality of middle insertion spaces 95. 11 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly liquid refrigerant) flowing into the second one-end side insertion space 92 of the heat exchanger of Example 3. As shown in FIG. 11 , the heat exchanger of Example 3 is provided with a one-end side communicating passage 106, which allows a portion of the liquid refrigerant flowing into the second one-end side insertion space 92 to flow out to the first one-end side insertion space 91 via the one-end side communicating passage 106. Therefore, the heat exchanger of Example 3 can make the flow rate of the liquid refrigerant flowing into the heat transfer tubes inserted into the second one-end side insertion space 92, among the plurality of heat transfer tubes 23, close to the flow rate of the liquid refrigerant flowing into the heat transfer tubes inserted into the plurality of middle insertion spaces 95, and can suppress refrigerant drift toward the plurality of heat transfer tubes 23.

[0061] In the heat exchanger of the first embodiment described above, low-pressure gas-liquid two-phase refrigerant may flow into the first one-end side insertion space 91 through both the first one-end side inlet hole 101 and the one-end side communicating passage 106, and the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the first one-end side insertion space 91 may be greater than the flow rate of the liquid refrigerant flowing into each of the plurality of middle insertion spaces 95. In the heat exchanger of the third embodiment, the first one-end side inlet hole 101 is not formed, and therefore the flow rate of the liquid refrigerant flowing into the first one-end side insertion space 91 can be reduced. Therefore, the flow rate of the liquid refrigerant flowing into the first one-end side insertion space 91 can be made closer to the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. Furthermore, the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the first one-end side insertion space 91 can be made closer to the flow rate of the liquid refrigerant flowing into the heat transfer tubes 23 inserted into the plurality of middle insertion spaces 95. Therefore, the heat exchanger of the third embodiment can suppress uneven flow of the refrigerant into the plurality of heat transfer tubes 23.

[0062] As in the heat exchanger of the first embodiment, liquid refrigerant may accumulate in the upper end region 97 of the first flow path 57 when a large amount of refrigerant circulates through the refrigerant circuit 4. When liquid refrigerant accumulates in the upper end region 97, the flow rate of the liquid refrigerant flowing into the second other-end side insertion space 94 through the second other-end side inlet 104 may be greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95 from the first flow path 57. FIG. 12 is a cross-sectional view showing the flow of low-pressure gas-liquid two-phase refrigerant (particularly liquid refrigerant) flowing into the second other-end side insertion space 94 of the heat exchanger of the third embodiment. As shown in FIG. 12, the heat exchanger of the third embodiment has the other-end side communicating passage 107, which allows a portion of the liquid refrigerant flowing into the second other-end side insertion space 94 through the second other-end side inlet 104 to flow into the first other-end side insertion space 93. Therefore, in the heat exchanger of Example 3, the flow rate of liquid refrigerant flowing into the heat transfer tube inserted into the second other-end side insertion space 94 among the plurality of heat transfer tubes 23 can be made closer to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into the plurality of middle insertion spaces 95, and the uneven flow of refrigerant into the plurality of heat transfer tubes 23 can be suppressed.

[0063] In the heat exchanger of the first embodiment described above, low-pressure gas-liquid two-phase refrigerant may flow into the first other-end side insertion space 93 through both the first other-end side inlet hole 103 and the other-end side communicating passage 107, and the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the first other-end side insertion space 93 may be greater than the flow rate of the liquid refrigerant flowing into the plurality of middle insertion spaces 95. In the heat exchanger of the third embodiment, the first other-end side inlet hole 103 is not formed, and therefore the flow rate of the liquid refrigerant flowing into the first other-end side insertion space 93 can be reduced. Therefore, the flow rate of the liquid refrigerant flowing into the second other-end side insertion space 94 can be made closer to the flow rate of the liquid refrigerant flowing into each of the plurality of middle insertion spaces 95. Furthermore, the flow rate of the liquid refrigerant flowing into the heat transfer tube inserted into the first other-end side insertion space 93 among the plurality of heat transfer tubes 23 can be made close to the flow rate of the liquid refrigerant flowing into the heat transfer tubes inserted into each of the plurality of middle insertion spaces 95. Therefore, the heat exchanger of the third embodiment can suppress uneven flow of the refrigerant into the plurality of heat transfer tubes 23.

[0064] Incidentally, the heat exchanger of the previously described Example 3 does not have the first one-end side inlet hole 101 but has the second one-end side inlet hole 102, but similar to the heat exchanger of the previously described Example 2, it is also possible for the first one-end side inlet hole 101 to be formed but not the second one-end side inlet hole 102. Also, the heat exchanger of the previously described Example 3 does not have the first other-end side inlet hole 103 but has the second other-end side inlet hole 104, but similar to the heat exchanger of the previously described Example 2, it is also possible for the first other-end side inlet hole 103 to be formed but not the second other-end side inlet hole 104. [Example]

[0065] Fig. 13 is a cross-sectional view showing a first one-end side insertion space 91 and a second one-end side insertion space 92 of a heat exchanger of Example 4. As shown in Fig. 13, in the heat exchanger of Example 4, one heat transfer tube inserted into the first one-end side insertion space 91 of the plurality of heat transfer tubes 23 of the heat exchanger of Example 1 described above is replaced with two heat transfer tubes 121. In the heat exchanger of Example 4, further, one heat transfer tube inserted into the second one-end side insertion space 92 of the plurality of heat transfer tubes 23 of the heat exchanger of Example 1 described above is replaced with two heat transfer tubes 122. Fig. 14 is a cross-sectional view showing a first other-end side insertion space 93 and a second other-end side insertion space 94 of the heat exchanger of Example 4. 14 , in the heat exchanger of Example 4, one of the heat transfer tubes 23 of the heat exchanger of Example 1 that is inserted into the first other-end side insertion space 93 is replaced with two heat transfer tubes 123. In the heat exchanger of Example 4, one of the heat transfer tubes 23 of the heat exchanger of Example 1 that is inserted into the second other-end side insertion space 94 is replaced with two heat transfer tubes 124. Similar to the heat exchanger of Example 1, one of the heat transfer tubes 23 is inserted into each of the plurality of middle insertion spaces 95.

[0066] When the heat exchanger of Example 4 functions as an evaporator, liquid refrigerant flows into the two heat transfer tubes 121 from the first one-end side insertion space 91 so that the flow rate of the liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into one of the two heat transfer tubes 121 is approximately equal to the flow rate of the liquid refrigerant flowing into the other of the two heat transfer tubes 121. Liquid refrigerant flows into the two heat transfer tubes 122 from the second one-end side insertion space 92 so that the flow rate of the liquid refrigerant flowing into one of the two heat transfer tubes 122 is approximately equal to the flow rate of the liquid refrigerant flowing into the other of the two heat transfer tubes 122. Liquid refrigerant flows into the two heat transfer tubes 123 from the first other-end side insertion space 93 so that the flow rate of the liquid refrigerant flowing into one of the two heat transfer tubes 123 is approximately equal to the flow rate of the liquid refrigerant flowing into the other of the two heat transfer tubes 123. Liquid refrigerant flows into the two heat transfer tubes 124 from the second other-end side insertion space 94 so that the flow rate of the liquid refrigerant flowing into one of the two heat transfer tubes 124 is approximately equal to the flow rate of the liquid refrigerant flowing into the other of the two heat transfer tubes 124.

[0067] The heat exchanger of the first embodiment described above may be insufficient in suppressing uneven flow of the refrigerant into the heat transfer tubes 23. For example, in the heat exchanger of the first embodiment described above, the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into the first one-end-side insertion space 91 among the heat transfer tubes 23 may be greater than the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tubes inserted into each of the middle insertion spaces 95. Furthermore, in the heat exchanger of the first embodiment described above, the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into the second one-end-side insertion space 92 among the heat transfer tubes 23 may be greater than the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into each of the middle insertion spaces 95. In the heat exchanger of the first embodiment described above, the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into the first other-end side insertion space 93 among the plurality of heat transfer tubes 23 may be greater than the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tubes inserted into each of the plurality of middle insertion spaces 95. In the heat exchanger of the first embodiment described above, the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into the second other-end side insertion space 94 among the plurality of heat transfer tubes 23 may be greater than the flow rate of the two-phase gas-liquid refrigerant flowing into the heat transfer tube inserted into each of the plurality of middle insertion spaces 95.

[0068] The flow rate of the gas-liquid two-phase refrigerant flowing into each of the two heat transfer tubes 121 is smaller than the flow rate of the gas-liquid two-phase refrigerant flowing into one of the heat transfer tubes 23 of the heat exchanger of the previously described first embodiment that is inserted into the first one-end side insertion space 91, because the gas-liquid two-phase refrigerant flows into the two heat transfer tubes 121 from the first one-end side insertion space 91. The flow rate of the gas-liquid two-phase refrigerant flowing into each of the two heat transfer tubes 122 is smaller than the flow rate of the gas-liquid two-phase refrigerant flowing into one of the heat transfer tubes 23 of the heat exchanger of the previously described first embodiment that is inserted into the second one-end side insertion space 92, because the gas-liquid two-phase refrigerant flows into the two heat transfer tubes 122 from the second one-end side insertion space 92. The flow rate of the gas-liquid two-phase refrigerant flowing into each of the two heat transfer tubes 123 is smaller than the flow rate of the gas-liquid two-phase refrigerant flowing into one of the plurality of heat transfer tubes 23 of the heat exchanger of the previously described first embodiment that is inserted into the first other-end side insertion space 93, because the gas-liquid two-phase refrigerant flows into the two heat transfer tubes 123 from the first other-end side insertion space 93. The flow rate of the gas-liquid two-phase refrigerant flowing into each of the two heat transfer tubes 124 is smaller than the flow rate of the gas-liquid two-phase refrigerant flowing into one of the plurality of heat transfer tubes 23 of the heat exchanger of the previously described first embodiment that is inserted into the second other-end side insertion space 94, because the gas-liquid two-phase refrigerant flows into the two heat transfer tubes 124 from the second other-end side insertion space 94. Therefore, even when the heat exchanger of the first embodiment described above is insufficient in suppressing the uneven flow of refrigerant to the multiple heat transfer tubes 23, the heat exchanger of the fourth embodiment can make the flow rate of liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into each of the heat transfer tubes 121 to 124 close to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into each of the multiple middle insertion spaces 95 of the multiple heat transfer tubes 23, thereby suppressing the uneven flow of refrigerant to the multiple heat transfer tubes 23.

[0069] Incidentally, the heat exchanger of the previously described Example 4 is formed with both the first one-end side introduction hole 101 and the second one-end side introduction hole 102, but similar to the heat exchangers of the previously described Examples 2 and 3, it is also possible for one of the first one-end side introduction hole 101 and the second one-end side introduction hole 102 to be formed without the other. Furthermore, the heat exchanger of the previously described Example 1 is formed with both the first other-end side introduction hole 103 and the second other-end side introduction hole 104, but similar to the previously described heat exchangers of the previously described Examples 2 and 3, it is also possible for one of the first other-end side introduction hole 103 and the second other-end side introduction hole 104 to be formed without the other.

[0070] Incidentally, in the heat exchanger of the fourth embodiment described above, two heat transfer tubes are inserted into each of the first one-end side insertion space 91, the second one-end side insertion space 92, the first other-end side insertion space 93, and the second other-end side insertion space 94, but only one heat transfer tube may be inserted into any of the first one-end side insertion space 91, the second one-end side insertion space 92, the first other-end side insertion space 93, and the second other-end side insertion space 94. Also, in the heat exchanger of the fourth embodiment described above, one heat transfer tube is inserted into each of the multiple middle insertion spaces 95, but the number of heat transfer tubes inserted into the first one-end side insertion space 91, the second one-end side insertion space 92, the first other-end side insertion space 93, and the second other-end side insertion space 94 may be the same. [Example]

[0071] FIG. 15 is a side view showing an expansion valve side header 130 of a heat exchanger of Example 5. As shown in FIG. 15, the heat exchanger of Example 5 has the expansion valve side header 21 of the heat exchanger of Example 1 already described replaced with another expansion valve side header 130. The heat exchanger of Example 5 further includes three branch pipes 131 to 133 and a flow divider (not shown). The flow divider is connected to the refrigerant pipe 17 and to the three branch pipes 131 to 133. The expansion valve side header 130 includes three expansion valve side header sections 134 to 136. The three expansion valve side header sections 134 to 136 are aligned in the header longitudinal direction 25.

[0072] Of the three expansion valve side header sections 134 to 136, the first expansion valve side header section 134 is formed with an inflow space 43, a refrigerant piping through-hole 44, a circulation flow path 45, an inlet 61, a plurality of insertion spaces 46, a plurality of heat transfer tube through-holes 47, and a plurality of introduction holes 62, similar to the previously described expansion valve side header 21. The first expansion valve side header section 134 is connected to the flow divider via the first branch pipe 131 by inserting the first branch pipe 131 into the refrigerant piping through-hole 44.

[0073] Of the three expansion valve side header sections 134 to 136, the second expansion valve side header section 135 is formed with an inflow space 43, a refrigerant piping through-hole 44, a circulation flow path 45, an inlet 61, a plurality of insertion spaces 46, a plurality of heat transfer tube through-holes 47, and a plurality of introduction holes 62, similar to the previously described expansion valve side header 21. The second expansion valve side header section 135 is connected to the flow divider via the second branch pipe 132 by inserting the second branch pipe 132 into the refrigerant piping through-hole 44.

[0074] Of the three expansion valve side header sections 134 to 136, the third expansion valve side header section 136 is formed with an inflow space 43, a refrigerant piping through-hole 44, a circulation flow path 45, an inlet 61, a plurality of insertion spaces 46, a plurality of heat transfer tube through-holes 47, and a plurality of introduction holes 62, similar to the previously described expansion valve side header 21. The third expansion valve side header section 136 is connected to the flow divider via the third branch pipe 133 by inserting the third branch pipe 133 into the refrigerant piping through-hole 44.

[0075] The plurality of heat transfer tubes 23 include a plurality of first heat transfer tubes 137, a plurality of second heat transfer tubes 138, and a plurality of third heat transfer tubes 139. The plurality of first heat transfer tubes 137, the plurality of second heat transfer tubes 138, and the plurality of third heat transfer tubes 139 are aligned in the header longitudinal direction 25. The plurality of first heat transfer tubes 137 are joined to the first expansion valve side header portion 134 so that one ends of the plurality of first heat transfer tubes 137 are disposed in the plurality of insertion spaces 46 of the first expansion valve side header portion 134. The plurality of second heat transfer tubes 138 are joined to the second expansion valve side header portion 135 so that one ends of the plurality of second heat transfer tubes 138 are disposed in the plurality of insertion spaces 46 of the second expansion valve side header portion 135. The multiple third heat transfer pipes 139 are joined to the third expansion valve side header portion 136 so that one ends of the multiple third heat transfer pipes 139 are positioned in the multiple insertion spaces 46 of the third expansion valve side header portion 136.

[0076] That is, the heat exchanger of Example 5 includes three heat exchange sections 141 to 143. Of the three heat exchange sections 141 to 143, the first heat exchange section 141 includes a first branch pipe 131, a first expansion valve side header section 134, and a plurality of first heat transfer pipes 137. Of the three heat exchange sections 141 to 143, the second heat exchange section 142 includes a second branch pipe 132, a second expansion valve side header section 135, and a plurality of second heat transfer pipes 138. Of the three heat exchange sections 141 to 143, the third heat exchange section 143 includes a third branch pipe 133, a third expansion valve side header section 136, and a plurality of third heat transfer pipes 139. In this case, the three heat exchange sections 141 to 143 are aligned in the header longitudinal direction 25.

[0077] When the heat exchanger of the fifth embodiment functions as an evaporator, the flow divider divides the low-pressure gas-liquid two-phase refrigerant supplied through the refrigerant pipe 17 so that the flow rates of the liquid refrigerant are approximately the same, and supplies the refrigerant to three expansion valve side header sections 134-136 via three branch pipes 131-133. Similar to the expansion valve side header 21 of the heat exchanger of the first embodiment described above, the first expansion valve side header section 134 divides the low-pressure gas-liquid two-phase refrigerant supplied through the first branch pipe 131 to the multiple first heat transfer pipes 137 so that the flow rates of the liquid refrigerant flowing into the multiple first heat transfer pipes 137 are the same. Similar to the expansion valve side header 21 of the heat exchanger of the first embodiment described above, the second expansion valve side header portion 135 divides the low-pressure gas-liquid two-phase refrigerant supplied via the second branch pipe 132 into the plurality of second heat transfer pipes 138 so that the flow rates of liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the plurality of second heat transfer pipes 138 are equal to each other. Similar to the expansion valve side header 21 of the heat exchanger of the first embodiment described above, the third expansion valve side header portion 136 divides the low-pressure gas-liquid two-phase refrigerant supplied via the third branch pipe 133 into the plurality of third heat transfer pipes 139 so that the flow rates of liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the plurality of third heat transfer pipes 139 are equal to each other.

[0078] In the heat exchanger of Example 5, the number of heat transfer tubes connected to each of the three expansion valve side header sections 134-136 can be made smaller than the number of heat transfer tubes connected to the expansion valve side header 21 of the heat exchanger of Example 1 described above. In the heat exchanger of Example 5, the number of heat transfer tubes connected to each of the three expansion valve side header sections 134-136 is made smaller, which reduces the difficulty of dividing the refrigerant into the heat transfer tubes of the three expansion valve side header sections 134-136 and further suppresses uneven flow to the plurality of heat transfer tubes 23. Furthermore, in the heat exchanger of Example 1 described above, as the number of heat transfer tubes 23 connected to the expansion valve side header 21 increases, the length of the first flow path 57 increases, making it more difficult for the liquid refrigerant to reach the upper end region 97 of the first flow path 57 due to the effect of gravity. The heat exchanger of Example 5 can ensure the amount of liquid refrigerant that reaches the upper end region 97 of the first flow path 57 of each of the three expansion valve side header portions 134 to 136, even when the number of heat transfer tubes 23 is large, and can suppress uneven flow to the heat transfer tubes 23.

[0079] Although the heat exchanger of the fifth embodiment described above is provided with three heat exchange sections 141-142, it may be provided with two heat exchange sections, or may be provided with four or more heat exchange sections. Even in such cases, the heat exchanger of the fifth embodiment described above can further suppress uneven flow to the plurality of heat transfer tubes 23.

[0080] The three expansion valve side header portions 134 to 136 of the heat exchanger of the above-described fifth embodiment are formed similarly to the expansion valve side header 21 of the heat exchanger of the above-described first embodiment, but may also be formed similarly to the expansion valve side headers of the heat exchangers of the other embodiments. Even in such a case, the heat exchanger of the above-described fifth embodiment can suppress uneven flow to the plurality of heat transfer tubes 23.

[0081] Incidentally, the three heat exchange sections 141-142 of the heat exchanger according to the fifth embodiment are aligned in the header longitudinal direction 25, but they may be aligned in a direction different from the header longitudinal direction 25. An example of the direction in which the three heat exchange sections 141-142 are aligned is the ventilation direction 20. Even in such a case, the heat exchanger according to the fifth embodiment can reduce the number of heat transfer tubes connected to each of the three expansion valve side header sections 134-136 and can ensure the amount of liquid refrigerant that reaches the upper end region 97 of the first flow path 57, thereby suppressing uneven flow to the multiple heat transfer tubes 23.

[0082] Incidentally, the heat exchangers of the above-described Examples 1 to 5 are arranged so that the other end 42 is located higher than the one end 41, but the one end 41 may be arranged so that it is located higher than the other end 42. Also, the header longitudinal direction 25 is arranged so that it is parallel to the vertical direction, but the header longitudinal direction 25 may be arranged so that it is not parallel to the vertical direction.

[0083] Incidentally, the heat exchangers of the first to fifth embodiments described above are formed with both the one-end side communicating passage 106 and the other-end side communicating passage 107, but it is also possible for one of the one-end side communicating passage 106 and the other-end side communicating passage 107 to be formed without the other. Even when the one-end side communicating passage 106 is not formed, the heat exchanger can make the flow rate of liquid refrigerant in the low-pressure gas-liquid two-phase refrigerant flowing into the heat transfer tubes inserted into the first other-end side insertion space 93 or the second other-end side insertion space 94 of the multiple heat transfer tubes 23 close to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into the multiple middle insertion spaces 95. Even when the other-end side connecting passage 107 is not formed, the heat exchanger can make the flow rate of liquid refrigerant among the low-pressure gas-liquid two-phase refrigerant flowing into the heat transfer tubes inserted into the first one-end side insertion space 91 or the second one-end side insertion space 92 among the multiple heat transfer tubes 23 close to the flow rate of liquid refrigerant flowing into the heat transfer tubes inserted into the multiple middle insertion spaces 95.

[0084] Incidentally, the expansion valve-side header 21 of the heat exchangers of the first to fifth embodiments described above is formed with the first flow path 57, the second flow path 58, the first return flow path 51, and the second return flow path 52. However, the second flow path 58, the first return flow path 51, and the second return flow path 52 do not have to be formed. Even when the second flow path 58, the first return flow path 51, and the second return flow path 52 are not formed in the heat exchanger, liquid refrigerant may accumulate in the inflow space 43, the lower end region 96, or the upper end region 97. Even when the second flow path 58, the first return flow path 51, and the second return flow path 52 are not formed in the heat exchanger, the heat exchanger can suppress uneven flow of liquid refrigerant to the plurality of heat transfer tubes 23, similar to the heat exchangers of the first to fifth embodiments described above.

[0085] Although the embodiments have been described above, the embodiments are not limited to the above content. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, at least one of various omissions, substitutions, and modifications of the components can be made without departing from the spirit of the embodiments. [Explanation of symbols]

[0086] 1: Outdoor heat exchanger (heat exchanger) 21, 111, 112, 130: Expansion valve side header (header) 23: Heat transfer tube 25: Header longitudinal direction (longitudinal direction) 41:One end 42:Other end 43:Inflow space 45: Circulation channel (diversion channel) 46: Multiple insertion spaces 57: First flow path 61:Inlet 62: Multiple inlet holes 91: First end side insertion space 92: Second one end side insertion space 93: First other end side insertion space 94: Second other end side insertion space 95: Multiple inner insertion spaces 96: Bottom area 97:Top area 101: First end side introduction hole 102: Second one end side introduction hole 103: First other end side introduction hole 104: Second other end side introduction hole 105: Multiple middle inlet holes 106: One end side communication path 107:Other end side communication path 141-143: Three heat exchange sections

Claims

1. A plurality of heat transfer tubes; a header to which the plurality of heat transfer tubes are joined, The header may include: a branch flow passage through which the refrigerant flows from one end side to the other end side in the longitudinal direction of the header; an inflow space adjacent to one end of the branch flow passage in the longitudinal direction of the header, for allowing a refrigerant to flow into the branch flow passage; an inlet for allowing the refrigerant to flow from the inlet space into the branch flow passage on one end side in the longitudinal direction of the header; a plurality of insertion spaces are formed, the insertion spaces being aligned in the longitudinal direction of the header and into which one ends of the plurality of heat transfer tubes are respectively disposed; The plurality of insertion spaces are: a first one-end side insertion space adjacent to the inflow space; a second one-end side insertion space adjacent to the first one-end side insertion space; a first other end side insertion space arranged closest to the other end; a second other end side insertion space adjacent to the first other end side insertion space; a plurality of inner insertion spaces different from the first one-end side insertion space, the second one-end side insertion space, the first other-end side insertion space, and the second other-end side insertion space; The header may include: At least one of a one-end-side communication passage that communicates the first one-end-side insertion space and the second one-end-side insertion space and an other-end-side communication passage that communicates the first other-end-side insertion space and the second other-end-side insertion space is formed, a plurality of inner introduction holes are further formed to respectively connect the plurality of inner insertion spaces to the branch flow passages; The header may include: When the one-end side communication passage is formed, at least one of a first one-end side introduction hole that communicates the inflow space with the first one-end side insertion space and a second one-end side introduction hole that communicates the branch flow passage with the second one-end side insertion space is further formed, When the other-end side communication passage is formed, at least one of a first other-end side introduction hole that communicates the branch flow passage with the first other-end side insertion space and a second other-end side introduction hole that communicates the branch flow passage with the second other-end side insertion space is further formed, The header is formed such that a communication passage that communicates each of the inner insertion spaces with the other insertion spaces is not formed in a partition that separates each of the inner insertion spaces from another insertion space adjacent to the inner insertion space among the plurality of insertion spaces. heat exchanger.

2. A plurality of heat transfer tubes; a header to which the plurality of heat transfer tubes are joined, The header may include: a branch flow passage through which the refrigerant flows from one end side to the other end side in the longitudinal direction of the header; an inflow space disposed on one end side of the branch flow path in the longitudinal direction of the header; an inlet for allowing the refrigerant to flow from the inlet space into the branch flow passage on one end side in the longitudinal direction of the header; a plurality of insertion spaces are formed, the insertion spaces being aligned in the longitudinal direction of the header and into which one ends of the plurality of heat transfer tubes are respectively disposed; The plurality of insertion spaces are: a first one-end side insertion space adjacent to the inflow space; a second one-end side insertion space adjacent to the first one-end side insertion space; a plurality of inner insertion spaces different from the first one-end side insertion space and the second one-end side insertion space; The header may include: a plurality of inner introduction holes that respectively connect the branch flow path to the plurality of inner insertion spaces; a one-end side communication passage that communicates the first one-end side insertion space and the second one-end side insertion space; a second one-end side introduction hole that communicates the branch flow path with the second one-end side insertion space is formed; The header is formed so that a first one-end side introduction hole that communicates the inflow space with the first one-end side insertion space is not formed between the inflow space and the first one-end side insertion space. heat exchanger.

3. The plurality of insertion spaces are: a first other end side insertion space arranged closest to the other end; a second other end side insertion space adjacent to the first other end side insertion space, The header may include: an other-end-side communication passage that communicates the first other-end-side insertion space with the second other-end-side insertion space; At least one of a first other-end side introduction hole that communicates the branch flow path with the first other-end side insertion space and a second other-end side introduction hole that communicates the branch flow path with the second other-end side insertion space is further formed.

3. The heat exchanger of claim 2.

4. The header is formed so that an introduction hole that communicates the branch flow passage with the first other-end-side insertion space is not formed between the branch flow passage and the first other-end-side insertion space.

4. The heat exchanger according to claim 3.

5. The other end is disposed above the one end.

3. The heat exchanger of claim 2.

6. One ends of two or more heat transfer tubes among the plurality of heat transfer tubes are arranged in the first one-end side insertion space, In the second one-end-side insertion space, one ends of two or more other heat transfer tubes among the plurality of heat transfer tubes are disposed.

3. The heat exchanger of claim 2.

7. one ends of two or more heat transfer tubes among the plurality of heat transfer tubes are arranged in the first other-end side insertion space, In the second other-end-side insertion space, one ends of two or more other heat transfer tubes among the plurality of heat transfer tubes are disposed.

4. The heat exchanger according to claim 3.

8. The header further includes a loop flow path that connects the other end of the branch flow path with the one end of the branch flow path.

7. The heat exchanger of claim 6.

9. a plurality of heat exchange units each having the plurality of heat transfer tubes and the header; The plurality of heat exchange units are arranged side by side.

8. The heat exchanger of claim 7.

10. The plurality of heat exchange units are stacked in the longitudinal direction of the header.

10. The heat exchanger of claim 9.

11. A plurality of heat transfer tubes; a header to which the plurality of heat transfer tubes are joined, The header may include: a branch flow passage through which the refrigerant flows from one end side to the other end side in the longitudinal direction of the header; an inflow space disposed on one end side of the branch flow path in the longitudinal direction of the header; an inlet for allowing the refrigerant to flow from the inlet space into the branch flow passage on one end side in the longitudinal direction of the header; a plurality of insertion spaces are formed, the insertion spaces being aligned in the longitudinal direction of the header and into which one ends of the plurality of heat transfer tubes are respectively disposed; The plurality of insertion spaces are: a first one-end side insertion space adjacent to the inflow space; a second one-end side insertion space adjacent to the first one-end side insertion space; a plurality of inner insertion spaces different from the first one-end side insertion space and the second one-end side insertion space; The header may include: a plurality of inner introduction holes that respectively connect the branch flow path to the plurality of inner insertion spaces; a one-end side communication passage that communicates the first one-end side insertion space and the second one-end side insertion space is formed; a first one-end side introduction hole that communicates the inflow space with the first one-end side insertion space is formed; The header is formed so that a second one-end side introduction hole that communicates the branch flow passage with the second one-end side insertion space is not formed between the branch flow passage and the second one-end side insertion space. heat exchanger.

12. A plurality of heat transfer tubes; a header to which the plurality of heat transfer tubes are joined, The header may include: a branch flow passage through which the refrigerant flows from one end side to the other end side in the longitudinal direction of the header; an inflow space disposed on one end side of the branch flow path in the longitudinal direction of the header; an inlet for allowing the refrigerant to flow from the inlet space into the branch flow passage on one end side in the longitudinal direction of the header; a plurality of insertion spaces are formed, the insertion spaces being aligned in the longitudinal direction of the header and into which one ends of the plurality of heat transfer tubes are respectively disposed; The plurality of insertion spaces are: a first other end side insertion space arranged closest to the other end; a second other end side insertion space adjacent to the first other end side insertion space; a plurality of inner insertion spaces different from the first other end side insertion space and the second other end side insertion space; The header may include: a plurality of inner introduction holes that respectively connect the branch flow path to the plurality of inner insertion spaces; an other-end-side communication passage that communicates the first other-end-side insertion space with the second other-end-side insertion space; a second other-end-side introduction hole that communicates the inflow space with the second other-end-side insertion space is formed; The header is formed so that a first other-end side introduction hole that communicates the branch flow passage with the first other-end side insertion space is not formed between the branch flow passage and the first other-end side insertion space. heat exchanger.

13. A plurality of heat transfer tubes; a header to which the plurality of heat transfer tubes are joined, The header may include: a branch flow passage through which the refrigerant flows from one end side to the other end side in the longitudinal direction of the header; an inflow space disposed on one end side of the branch flow path in the longitudinal direction of the header; an inlet for allowing the refrigerant to flow from the inlet space into the branch flow passage on one end side in the longitudinal direction of the header; a plurality of insertion spaces are formed, the insertion spaces being aligned in the longitudinal direction of the header and into which one ends of the plurality of heat transfer tubes are respectively disposed; The plurality of insertion spaces are: a first other end side insertion space arranged closest to the other end; a second other end side insertion space adjacent to the first other end side insertion space; a plurality of inner insertion spaces different from the first other end side insertion space and the second other end side insertion space; The header may include: a plurality of inner introduction holes that respectively connect the branch flow path to the plurality of inner insertion spaces; an other-end-side communication passage that communicates the first other-end-side insertion space with the second other-end-side insertion space; a second other-end-side introduction hole that communicates the inflow space with the second other-end-side insertion space is formed; The header is formed so that a second other-end side introduction hole that communicates the branch flow passage with the second other-end side insertion space is not formed between the branch flow passage and the second other-end side insertion space. heat exchanger.

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