Heat Exchanger

Abstract

A heat exchanger comprises: an inlet header (120) having a first inlet space and a second inlet space adjacent to the first inlet space; a plurality of inlet-side heat transfer tubes (111a) including a plurality of first inlet-side heat transfer tubes connected to the first inlet space and a plurality of second inlet-side heat transfer tubes connected to the second inlet space; a return header (170) having a plurality of return spaces formed therein, the plurality of return spaces including a plurality of first return spaces (5-1) respectively connected to the plurality of first inlet-side heat transfer tubes and a plurality of second return spaces (5-2) respectively connected to the plurality of second inlet-side heat transfer tubes; and a plurality of outlet-side heat transfer tubes (111b) respectively connected to the plurality of return spaces, wherein a connecting path (21) is also formed inside the return header (170) for connecting the first return space (6) at the bottom of the plurality of first return spaces (5-1) with the second return space (7) at the top of the plurality of second return spaces (5-2).

Description

Technical Field

[0001] The present invention relates to a heat exchanger. Background Art

[0002] The outdoor unit and the indoor unit of the air conditioner are provided with a heat exchanger, which functions as an evaporator or a condenser by exchanging heat between a refrigerant flowing through a heat transfer tube and air flowing around fins disposed around the heat transfer tube.

[0003] There is a heat exchanger as follows, which is provided by stacking a plurality of heat transfer tubes at intervals in the vertical direction, and arranging the stacked heat transfer tubes into a plurality of rows so that the refrigerant flows back and forth between the rows (for example, Patent Document 1). Specifically, the heat exchanger has: a plurality of first heat transfer tubes connected to a header (inlet header) on one side at one end, and a plurality of second heat transfer tubes connected to a header (outlet header) on the other side at one end. Furthermore, the heat exchanger has a return header connected to the other ends of the plurality of first heat transfer tubes and the other ends of the plurality of second heat transfer tubes. The return header has a space that connects the interiors of the first heat transfer tube and the second heat transfer tube connected at the same position in the vertical direction to each other. That is, an independent flow path is formed inside the return header for each layer. The refrigerant flowing into the inlet header is respectively diverted to each of the plurality of first heat transfer tubes in the inlet header. The refrigerant flowing through the plurality of first heat transfer tubes flows into the second heat transfer tubes in the same layer as the first heat transfer tubes through the return header. The refrigerant flowing through the plurality of second heat transfer tubes merges in the outlet header and flows out from the outlet header. As described above, by making the refrigerant flow back and forth, the length of the refrigerant flow path is increased, so that a large amount of refrigerant can be fully evaporated.

[0004] When the heat exchanger is used as an evaporator, the ideal state of the refrigerant flowing into the inlet header is a gas-liquid two-phase state. In the above heat exchanger, when the refrigerant is divided into each of the plurality of first heat transfer tubes in the inlet header, the refrigerant in the liquid phase falls and the refrigerant in the gas phase rises due to the influence of gravity. As a result, there is a problem that the distribution of the refrigerant in the inlet header is uneven, making it difficult to divide the refrigerant in the liquid phase and the refrigerant in the gas phase in a uniform state. In the stacked heat transfer tubes, the proportion of the gas phase of the refrigerant in the heat transfer tube flowing on the upper side is higher than the proportion of the gas phase of the refrigerant in the heat transfer tube flowing on the lower side. Since the amount of refrigerant that can be vaporized in the refrigerant with a high gas phase ratio (high dryness) is small, the latent heat used for heat exchange with the fluid outside the tube (air) is small. That is, the amount of heat exchange with the air in the upper heat transfer tube and the lower heat transfer tube in the stacked heat transfer tubes is different. As a result, before the refrigerant flowing in the heat transfer tube on the lower side completely evaporates, the refrigerant flowing in the heat transfer tube on the upper side has become overheated, resulting in an area in the heat exchanger that cannot perform the heat exchange function with the air. If a heat exchange area in the heat exchanger that cannot perform the heat exchange function with the air appears, the heat exchange capacity will be reduced. Therefore, the heat exchanger disclosed in Figure 10 of Patent Document 2 forms a plurality of spaces arranged in the vertical direction inside the inlet header, and the refrigerant flows into the plurality of spaces respectively. The length of each space in the vertical direction is smaller than the total length of the header in the vertical direction, thereby reducing the influence of gravity and enabling the refrigerant to be evenly distributed and flow into the plurality of flat tubes respectively connected to each space.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-214827

[0006] Patent Document 2: Japanese Patent Application Publication No. 2015-200497 Summary of the invention

[0007] However, due to the influence of gravity, the refrigerant state in each space is also uneven in the vertical direction. Since the return header forms an independent flow path for each layer, the uneven refrigerant state in the inlet header is not improved until it reaches the outlet header.

[0008] The disclosed technology has been proposed in view of the above problems, and its object is to provide a heat exchanger in which even if the refrigerant is unevenly distributed to a plurality of heat transfer tubes in an inlet header, the generation of a region where the heat exchange function with the air cannot be exerted can be suppressed.

[0009] According to one aspect of the present invention, a heat exchanger comprises: an inlet header having an inlet space formed therein, wherein the inlet space includes a first inlet space and a second inlet space adjacent to and below the first inlet space; an inlet-side heat transfer tube, which includes a plurality of first inlet-side heat transfer tubes connected to the first inlet space and arranged in a vertical direction, and a plurality of second inlet-side heat transfer tubes connected to the second inlet space and arranged in a vertical direction; a return header having a plurality of return spaces formed therein respectively connected to the plurality of inlet-side heat transfer tubes, wherein the plurality of return spaces include a plurality of first return spaces respectively connected to the plurality of first inlet-side heat transfer tubes and arranged in a vertical direction, and a plurality of second return spaces respectively connected to the plurality of second inlet-side heat transfer tubes and arranged in a vertical direction; and a plurality of outlet-side heat transfer tubes, wherein at least one of the outlet-side heat transfer tubes is connected to each of the plurality of return spaces and arranged in a vertical direction, wherein a connecting path is further formed in the return header to connect the first return space at the bottom of the plurality of first return spaces with the second return space at the top of the plurality of second return spaces.

[0010] The heat exchanger disclosed in the present invention can suppress the generation of a region where the heat exchange function with the air cannot be performed even if the refrigerant is distributed to the plurality of heat transfer tubes in an uneven state in the inlet header. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view showing the structure of the heat exchanger of Example 1.

[0012] Figure 2 Yes means Figure 1 Figure 2. Diagram of the II line cross section.

[0013] Figure 3 Yes means Figure 1 Figure 2 is a diagram of a cross section of line II-II.

[0014] Figure 4 It is a diagram showing the structure of a return header.

[0015] Figure 5 It is a diagram for explaining the shape of a return header.

[0016] Figure 6 is a schematic diagram showing a heat exchanger.

[0017] Figure 7 is another schematic diagram showing a heat exchanger.

[0018] Figure 8 It is a schematic diagram showing the return header.

[0019] Fig. 9 It is a schematic diagram showing the heat exchanger of Example 2. DETAILED DESCRIPTION

[0020] Hereinafter, the heat exchanger according to the embodiment disclosed in the present application will be described with reference to the accompanying drawings. In addition, the technology of the present invention is not limited to the following description. In addition, in the following description, the same components are denoted by the same reference numerals and repeated descriptions are omitted.

[0021] Example 1

[0022] Figure 1 It is a perspective view showing the structure of the heat exchanger 100 according to the first embodiment. Figure 1 The heat exchanger 100 shown is provided in, for example, an outdoor unit of an air conditioner and operates as an evaporator or a condenser. The heat exchanger 100 includes a heat exchanger core 110 , an inlet header 120 , an inlet pipe 130 , an outlet header 140 , an outlet pipe 150 , and a return header 170 .

[0023] The heat exchanger core 110 is L-shaped when viewed from above, and the number of rows of stacked heat transfer tubes is two. In addition, the heat exchanger core 110 has a plurality of fins that guide air around the heat transfer tubes to promote heat exchange between the air and the refrigerant flowing in the heat transfer tubes. Specifically, Figure 2 Yes means Figure 1 The II line cross section diagram, Figure 3 Yes means Figure 1 In addition, Figure 1 Detailed illustration of the heat transfer tubes and fins included in the heat exchanger core 110 is omitted.

[0024] like Figure 2 As shown, the heat exchanger core 110 includes: an inlet-side heat transfer tube 111a, an inlet-side fin 112a, an outlet-side heat transfer tube 111b, and an outlet-side fin 112b. The heat exchanger core 110 includes a row formed by stacking multiple layers of inlet-side heat transfer tubes 111a at intervals and a row formed by stacking multiple layers of outlet-side heat transfer tubes 111b at intervals, and the inlet-side heat transfer tubes 111a and the outlet-side heat transfer tubes 111b of the same layer of each row are arranged in parallel in a manner of being close to each other and extending in parallel. The inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b are both flat tubes with flat cross-sections, and the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b have the same cross-sectional shape. On the cross-sections of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b, a plurality of refrigerant flow paths are arranged along the length direction. The inlet-side heat transfer tube 111 a extends from the inlet header 120 to the return header 170 , and the outlet-side heat transfer tube 111 b extends from the outlet header 140 to the return header 170 .

[0025] The inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b penetrate the comb-shaped inlet-side fin 112a and the outlet-side fin 112b extending in the stacking direction of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b. Figure 3 As shown, the inlet-side heat transfer tube 111a penetrates the plurality of inlet-side fins 112a, so that the refrigerant flowing inside the inlet-side heat transfer tube 111a and the air flowing between the plurality of inlet-side fins 112a can efficiently perform heat exchange. Similarly, the outlet-side heat transfer tube 111b penetrates the plurality of outlet-side fins 112b, so that the refrigerant flowing inside the outlet-side heat transfer tube 111b and the air flowing between the plurality of outlet-side fins 112b can efficiently perform heat exchange.

[0026] The inlet fin 112a and the outlet fin 112b extend in the stacking direction of the inlet heat transfer tube 111a and the outlet heat transfer tube 111b, and the inlet heat transfer tube 111a and the outlet heat transfer tube 111b are inserted between the teeth of the comb. That is, the inlet fin 112a is inserted through the plurality of inlet heat transfer tubes 111a arranged in a row in the stacking direction, and the outlet fin 112b is inserted through the plurality of outlet heat transfer tubes 111b arranged in a row in the stacking direction. There is a gap between adjacent inlet fins 112a in the extending direction of the inlet heat transfer tube 111a, and the space separated by the stacked inlet heat transfer tubes 111a and the adjacent inlet fins 112a is an air passage. Heat exchange is performed between the air flowing through the passage and the refrigerant flowing in the inlet heat transfer tube 111a. Similarly, there is a gap between the adjacent outlet fins 112b in the extending direction of the outlet heat transfer tube 111b, and the space separated by the stacked outlet heat transfer tubes 111b and the adjacent outlet fins 112b is an air passage. The air flowing through the passage exchanges heat with the refrigerant flowing in the outlet heat transfer tube 111b.

[0027] The inlet header 120 and the outlet header 140 are provided at one end of the heat exchanger 100. The inlet header 120 is connected to a plurality of inlet heat transfer tubes 111a arranged in a row in the stacking direction, and the outlet header 140 is connected to a plurality of outlet heat transfer tubes 111b arranged in a row in the stacking direction.

[0028] The inlet header 120 serves as an inlet header for the refrigerant when the heat exchanger 100 functions as an evaporator, and delivers the gas-liquid two-phase refrigerant flowing in from the inlet pipe 130 to the inlet-side heat transfer pipe 111a. In addition, the inlet header 120 serves as an outlet header for the refrigerant when the heat exchanger 100 functions as a condenser, and delivers the gas-liquid two-phase refrigerant flowing in from the inlet-side heat transfer pipe 111a to the inlet pipe 130.

[0029] The outlet header 140 serves as an outlet header of the refrigerant when the heat exchanger 100 functions as an evaporator, and delivers the refrigerant in a gas-liquid two-phase state or a gas-phase single-phase state flowing in from the outlet-side heat transfer tube 111b to the outflow pipe 150. In addition, the outlet header 140 serves as an inlet header of the refrigerant when the heat exchanger 100 functions as a condenser, and delivers the refrigerant in a gas-phase single-phase state flowing in from the outflow pipe 150 to the outlet-side heat transfer tube 111b.

[0030] The return header 170 is provided at the end of the heat exchanger 100 on the opposite side to the end provided with the inlet header 120 and the outlet header 140, and connects the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b. That is, the return header 170 has a space in which the front ends of a pair of inlet-side heat transfer tubes 111a and outlet-side heat transfer tubes 111b in the same layer are connected together, so that the refrigerant flowing out of the front end of the inlet-side heat transfer tube 111a is returned and flows into the outlet-side heat transfer tube 111b, and the refrigerant flowing in from the front end of the outlet-side heat transfer tube 111b is returned and flows into the inlet-side heat transfer tube 111a.

[0031] Figure 4 1 is a diagram showing the structure of the return header 170 . Figure 4 This is a perspective view of the return header 170 as viewed from the inlet-side heat transfer tube 111 a and the outlet-side heat transfer tube 111 b side (that is, the inside of the heat exchanger 100 ).

[0032] The return header 170 is formed by joining two plate-like members 171 and 172 by, for example, brazing. The end 171a of the plate-like member 171 in the arrangement direction of a pair of inlet-side heat transfer tubes 111a and outlet-side heat transfer tubes 111b in the same layer, i.e., in the row width direction (hereinafter referred to as "row width direction"), is bent toward the side where the inlet-side heat transfer tubes 111a and the outlet-side heat transfer tubes 111b are located, and the end 172a of the plate-like member 172 in the row width direction is also bent toward the side where the inlet-side heat transfer tubes 111a and the outlet-side heat transfer tubes 111b are located. Furthermore, the joining portion between the end 171a of the plate-like member 171 and the end 172a of the plate-like member 172 forms a bent portion 170a of the return header 170. That is, both ends in the row width direction of the joining portion of the two plate-like members 171 and 172 form the bent portion 170a bent toward the plate-like member 172 side.

[0033] A concave portion 171b corresponding to each layer of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b is formed in the center of the plate-like member 171, and a concave portion 172b corresponding to each layer of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b is formed in the center of the plate-like member 172. The plate-like members 171 and 172 are opposed to each other in such a manner that the concave portions 171b and 172b corresponding to the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b of the same layer are opposed to each other, and are joined in such a manner that a space is formed by the opposing concave portions 171b and 172b. The brazing material for joining the plate-like members 171 and 172 is contained in, for example, a coating formed on the surface of the plate-like member 172, and the brazing material is melted by heating the coating, thereby joining the plate-like member 171 and the plate-like member 172. The front ends of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b pass through the bottom of the recessed portion 172b, so that the space formed by the recessed portions 171b and 172b connects the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b. That is, the refrigerant can circulate between the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b through the space formed by the recessed portions 171b and 172b.

[0034] The portions other than the recessed portions 171b and 172b of the plate-like parts 171 and 172 are joint portions, and the joint portions are formed by, for example, brazing, to join the opposing plate-like parts 172 and 171. That is, the portions other than the recessed portions 171b of the plate-like part 171 are joint portions joined to the plate-like part 172, for example, by brazing, and the portions other than the recessed portions 172b of the plate-like part 172 are joint portions joined to the plate-like part 171, for example, by brazing. In order to ensure the joint strength of the plate-like parts 171 and 172, the joint portions of the plate-like parts 171 and 172 each have an area greater than a certain level. That is, for example Figure 4 The return header 170 shown has a large-area joint portion on the side of the recessed portions 171 b and 172 b.

[0035] As described above, the ends 171a and 172a of the joint in the row width direction are formed as the bent portion 170a of the return header 170. The bent portion 170a is bent in a manner substantially parallel to the extending direction of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b that pass through the bottom of the recess 172b. In other words, the bent portion 170a is bent substantially at a right angle to the joint around the recesses 171b and 172b.

[0036] Thus, the bent portion 170a can reduce the row width dimension of the return header 170 even if the area of ​​the joint of the plate members 171 and 172 needs to be increased to ensure the joint strength. As a result, the space occupied by the return header 170 can be reduced, thereby achieving space saving.

[0037] Figure 5 The diagram shows a cross section of the return header 170 cut along a plane perpendicular to the stacking direction of the inlet-side heat transfer tubes 111 a and the outlet-side heat transfer tubes 111 b (hereinafter simply referred to as “stacking direction”).

[0038] like Figure 5 As shown, the plate-like members 171 and 172 are joined in a manner such that the bottoms of the recessed portion 171b of the plate-like member 171 and the recessed portion 172b of the plate-like member 172 are opposite to each other, thereby forming a space 170b connecting the inlet-side heat transfer pipe 111a and the outlet-side heat transfer pipe 111b. The front ends of the inlet-side heat transfer pipe 111a and the outlet-side heat transfer pipe 111b pass through the bottom of the recessed portion 172b to reach the space 170b. Thus, the inlet-side heat transfer pipe 111a and the outlet-side heat transfer pipe 111b are connected through the space 170b.

[0039] The portion other than the recessed portions 171b and 172b is formed as a joint portion where the plate-like members 171 and 172 are joined by, for example, brazing, and both ends of the joint portion in the row width direction are formed as bent portions 170a, which are bent in a direction substantially parallel to the extending direction of the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b. That is, the end portion 171a in the row width direction of the plate-like member 171 is bent toward the side where the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b are located, and the end portion 172a in the row width direction of the plate-like member 172 is bent toward the side where the inlet-side heat transfer tube 111a and the outlet-side heat transfer tube 111b are located, and the bent portion 170a is formed by joining these two end portions 171a and 172a.

[0040] Figure 6 1 is a schematic diagram showing the heat exchanger 100 . Figure 7 1 is another schematic diagram showing the heat exchanger 100. The heat exchanger core 110 includes a first heat exchange section 1-1, a second heat exchange section 1-2, a third heat exchange section 1-3, and a fourth heat exchange section 1-4. When the heat exchanger 100 is properly arranged, the first heat exchange section 1-1, the second heat exchange section 1-2, the third heat exchange section 1-3, and the fourth heat exchange section 1-4 are arranged in the up-down direction. The first heat exchange section 1-1 includes a plurality of first inlet-side heat transfer tubes 1-1a and a plurality of first outlet-side heat transfer tubes 1-1b. The plurality of first inlet-side heat transfer tubes 1-1a are included in the plurality of inlet-side heat transfer tubes 111a and are arranged in the up-down direction. The plurality of first outlet-side heat transfer tubes 1-1b are included in the plurality of outlet-side heat transfer tubes 111b and are arranged in the up-down direction.

[0041] The second heat exchange unit 1-2 is disposed adjacently below the first heat exchange unit 1-1, and includes a plurality of second inlet-side heat transfer tubes 1-2a and a plurality of second outlet-side heat transfer tubes 1-2b. The plurality of second inlet-side heat transfer tubes 1-2a are included in the plurality of inlet-side heat transfer tubes 111a and are arranged in the vertical direction. The plurality of second outlet-side heat transfer tubes 1-2b are included in the plurality of outlet-side heat transfer tubes 111b and are arranged in the vertical direction. The uppermost second inlet-side heat transfer tube among the plurality of second inlet-side heat transfer tubes 1-2a is disposed adjacently below the lowermost first inlet-side heat transfer tube among the plurality of first inlet-side heat transfer tubes 1-1a. The uppermost second outlet-side heat transfer tube among the plurality of second outlet-side heat transfer tubes 1-2b is disposed below the lowermost first outlet-side heat transfer tube among the plurality of first outlet-side heat transfer tubes 1-1b. The second heat exchange unit 1 - 2 includes a plurality of second inlet-side heat transfer tubes 1 - 2a and a plurality of second outlet-side heat transfer tubes 1 - 2b .

[0042] The third heat exchange unit 1-3 is disposed adjacently below the second heat exchange unit 1-2, and includes a plurality of third inlet-side heat transfer tubes 1-3a and a plurality of third outlet-side heat transfer tubes 1-3b. The plurality of third inlet-side heat transfer tubes 1-3a are included in the plurality of inlet-side heat transfer tubes 111a and are arranged in the vertical direction. The plurality of third outlet-side heat transfer tubes 1-3b are included in the plurality of outlet-side heat transfer tubes 111b and are arranged in the vertical direction. The third inlet-side heat transfer tube at the uppermost side among the plurality of third inlet-side heat transfer tubes 1-3a is disposed adjacently below the second inlet-side heat transfer tube at the lowermost side among the plurality of second inlet-side heat transfer tubes 1-2a. The third outlet-side heat transfer tube at the uppermost side among the plurality of third outlet-side heat transfer tubes 1-3b is disposed adjacently below the second outlet-side heat transfer tube at the lowermost side among the plurality of second outlet-side heat transfer tubes 1-2b. The third heat exchange unit 1 - 3 includes a plurality of third inlet-side heat transfer tubes 1 - 3 a and a plurality of third outlet-side heat transfer tubes 1 - 3 b .

[0043] The fourth heat exchange unit 1-4 is disposed adjacently below the third heat exchange unit 1-3, and includes a plurality of fourth inlet-side heat transfer tubes 1-4a and a plurality of fourth outlet-side heat transfer tubes 1-4b. The plurality of fourth inlet-side heat transfer tubes 1-4a are included in the plurality of inlet-side heat transfer tubes 111a and are arranged in the vertical direction. The plurality of fourth outlet-side heat transfer tubes 1-4b are included in the plurality of outlet-side heat transfer tubes 111b and are arranged in the vertical direction. The fourth inlet-side heat transfer tube at the uppermost side among the plurality of fourth inlet-side heat transfer tubes 1-4a is disposed adjacently below the third inlet-side heat transfer tube at the lowermost side among the plurality of third inlet-side heat transfer tubes 1-3a. The fourth outlet-side heat transfer tube at the uppermost side among the plurality of fourth outlet-side heat transfer tubes 1-4b is disposed adjacently below the third outlet-side heat transfer tube at the lowermost side among the plurality of third outlet-side heat transfer tubes 1-3b. The fourth heat exchange unit 1 - 4 includes a plurality of fourth inlet-side heat transfer tubes 1 - 4 a and a plurality of fourth outlet-side heat transfer tubes 1 - 4 b .

[0044] The inlet header 120 is provided with a first inlet space 2-1, a second inlet space 2-2, a third inlet space 2-3, and a fourth inlet space 2-4. The first inlet space 2-1, the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 are isolated from each other. The first inlet space 2-1 is connected to a plurality of first inlet-side heat transfer tubes 1-1a of the first heat exchange unit 1-1. At this time, the ends of the plurality of first inlet-side heat transfer tubes 1-1a connected to the first inlet space 2-1 are arranged in a vertical direction.

[0045] The second inlet space 2-2 is arranged below the first inlet space 2-1. The second inlet space 2-2 is connected to the plurality of second inlet-side heat transfer tubes 1-2a of the second heat exchange unit 1-2. At this time, the ends of the plurality of second inlet-side heat transfer tubes 1-2a connected to the second inlet space 2-2 are arranged in a vertical direction.

[0046] The third inlet space 2-3 is arranged below the second inlet space 2-2. The third inlet space 2-3 is connected to a plurality of third inlet-side heat transfer tubes 1-3a of the third heat exchange unit 1-3. At this time, the ends of the plurality of third inlet-side heat transfer tubes 1-3a connected to the third inlet space 2-3 are arranged in a vertical direction.

[0047] The fourth inlet space 2-4 is arranged below the third inlet space 2-3. The fourth inlet space 2-4 is connected to a plurality of fourth inlet-side heat transfer tubes 1-4a of the fourth heat exchange unit 1-4. At this time, the ends of the plurality of fourth inlet-side heat transfer tubes 1-4a connected to the fourth inlet space 2-4 are arranged in a vertical direction.

[0048] The heat exchanger 100 further includes a flow divider 3. The flow divider 3 is connected to the first inlet space 2-1, the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 of the inlet header 120 through a plurality of inlet pipes 130. The flow divider 3 divides the gas-liquid two-phase refrigerant supplied to the first inlet space 2-1, the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 so that the dryness of the gas-liquid two-phase refrigerant is substantially the same, thereby supplying the gas-liquid two-phase refrigerant to the inlet header 120.

[0049] An outlet space 4 is formed in the outlet header 140. The outlet space 4 is connected to a plurality of first outlet-side heat transfer tubes 1-1b, a plurality of second outlet-side heat transfer tubes 1-2b, a plurality of third outlet-side heat transfer tubes 1-3b, and a plurality of fourth outlet-side heat transfer tubes 1-4b. That is, one end of the plurality of outlet-side heat transfer tubes 111b is disposed in the outlet space 4. The return header 170 is connected to the other end of the first heat exchange unit 1-1, the second heat exchange unit 1-2, the third heat exchange unit 1-3, and the fourth heat exchange unit 1-4 on the opposite side of the one end connected to the inlet header 120 and the outlet header 140.

[0050] Figure 8 1 is a schematic diagram showing the return header 170. The return header 170 is formed with Figure 8 The right arrow indicates a plurality of return spaces. Each of the plurality of return spaces is formed in the same manner as space 170b, and the plurality of return spaces are isolated from each other. The total number of the plurality of return spaces is the same as the total number of inlet-side heat transfer tubes 111a, and is the same as the total number of outlet-side heat transfer tubes 111b. The plurality of return spaces include a plurality of first return spaces 5-1, a plurality of second return spaces 5-2, a plurality of third return spaces 5-3, and a plurality of fourth return spaces 5-4. The plurality of first return spaces 5-1 are respectively connected to a plurality of first inlet-side heat transfer tubes 1-1a, and are respectively connected to a plurality of first outlet-side heat transfer tubes 1-1b. That is, each of the plurality of first return spaces 5-1 is connected to one first inlet-side heat transfer tube among the plurality of first inlet-side heat transfer tubes 1-1a, and is connected to one first outlet-side heat transfer tube among the plurality of first outlet-side heat transfer tubes 1-1b.

[0051] The plurality of first return spaces 5-1 include a first lower (lowest) first return space 6. The lowest first return space 6 is connected to the lowest first inlet heat transfer tube among the plurality of first inlet heat transfer tubes 1-1a. The lowest first inlet heat transfer tube is a flow path arranged at the lowest side among the plurality of first inlet heat transfer tubes 1-1a, and one end of the lowest first inlet heat transfer tube connected to the first inlet space 2-1 is connected to the lowest part of the first inlet space 2-1. That is, one end of the other first inlet heat transfer tubes different from the lowest first inlet heat transfer tube among the plurality of first inlet heat transfer tubes 1-1a is arranged at a position above the position where one end of the lowest first inlet heat transfer tube is arranged in the first inlet space 2-1.

[0052] The plurality of second return spaces 5-2 are respectively connected to the plurality of second inlet-side heat transfer tubes 1-2a, and are respectively connected to the plurality of second outlet-side heat transfer tubes 1-2b. That is, each space of the plurality of second return spaces 5-2 is connected to one second inlet-side heat transfer tube among the plurality of second inlet-side heat transfer tubes 1-2a, and is connected to one second outlet-side heat transfer tube among the plurality of second outlet-side heat transfer tubes 1-2b. The plurality of second return spaces 5-2 include a first upper (uppermost) second return space 7. The uppermost second return space 7 is connected to the uppermost second inlet-side heat transfer tube among the plurality of second inlet-side heat transfer tubes 1-2a. The uppermost second inlet-side heat transfer tube is a flow path arranged at the uppermost side among the plurality of second inlet-side heat transfer tubes 1-2a, and one end of the uppermost second inlet-side heat transfer tube connected to the second inlet space 2-2 is connected to the uppermost portion of the second inlet space 2-2. That is, one end of another second inlet heat transfer tube different from the uppermost second inlet heat transfer tube among the plurality of second inlet heat transfer tubes 1-2a is arranged at a location below the location where one end of the uppermost second inlet heat transfer tube is arranged in the second inlet space 2-2.

[0053] The plurality of second return spaces 5-2 further include a second return space 11 at the bottom and a second return space 12 at the second bottom. The second return space 11 at the bottom is connected to the second inlet heat transfer tube at the bottom among the plurality of second inlet heat transfer tubes 1-2a. The second inlet heat transfer tube at the bottom is a flow path arranged at the bottom among the plurality of second inlet heat transfer tubes 1-2a, and one end of the second inlet heat transfer tube at the bottom that is connected to the second inlet space 2-2 is connected to the bottom part of the second inlet space 2-2. The second lower second return space 12 is connected to the second lower second inlet heat transfer tube among the plurality of second inlet heat transfer tubes 1-2a. The second lower second inlet heat transfer tube is a flow path arranged at the second lower side among the plurality of second inlet heat transfer tubes 1-2a. One end of the second lower second inlet-side heat transfer tube connected to the second inlet space 2-2 is connected to one end of the lowermost second inlet-side heat transfer tube and is connected to the second lower portion of the second inlet space 2-2.

[0054] The plurality of third return spaces 5-3 are respectively connected to the plurality of third inlet-side heat transfer tubes 1-3a, and are respectively connected to the plurality of third outlet-side heat transfer tubes 1-3b. That is, each space of the plurality of third return spaces 5-3 is connected to one third inlet-side heat transfer tube among the plurality of third inlet-side heat transfer tubes 1-3a, and is connected to one third outlet-side heat transfer tube among the plurality of third outlet-side heat transfer tubes 1-3b. The plurality of third return spaces 5-3 include the third return space 14 at the uppermost side and the third return space 15 at the second uppermost side. The third return space 14 at the uppermost side is connected to the third inlet-side heat transfer tube at the uppermost side among the plurality of third inlet-side heat transfer tubes 1-3a. The third inlet-side heat transfer tube at the uppermost side is the flow path arranged at the uppermost side among the plurality of third inlet-side heat transfer tubes 1-3a, and one end of the third inlet-side heat transfer tube at the uppermost side connected to the third inlet space 2-3 is connected to the uppermost part of the third inlet space 2-3. That is, one end of the other third inlet-side heat transfer tubes different from the third inlet-side heat transfer tube at the top among the plurality of third inlet-side heat transfer tubes 1-3a is arranged at a portion of the third inlet space 2-3 that is lower than the portion where one end of the third inlet-side heat transfer tube at the top is arranged. The third return space 15 at the second top is connected to the third inlet-side heat transfer tube at the second top among the plurality of third inlet-side heat transfer tubes 1-3a. The third inlet-side heat transfer tube at the second top is a flow path arranged at the second top next to the third inlet-side heat transfer tube at the top among the plurality of third inlet-side heat transfer tubes 1-3a. One end of the third inlet-side heat transfer tube at the second top that is connected to the third inlet space 2-3 is connected to one end of the third inlet-side heat transfer tube at the top and is connected to the portion at the second top.

[0055] The plurality of third return spaces 5-3 further include a third return space 16 at the bottom. The third return space 16 at the bottom is connected to the third inlet heat transfer tube at the bottom among the plurality of third inlet heat transfer tubes 1-3a. The third inlet heat transfer tube at the bottom is a flow path arranged at the bottom among the plurality of third inlet heat transfer tubes 1-3a, and one end of the third inlet heat transfer tube at the bottom that is connected to the third inlet space 2-3 is connected to the bottom portion of the third inlet space 2-3. That is, one end of the other third inlet heat transfer tubes different from the third inlet heat transfer tube at the bottom among the plurality of third inlet heat transfer tubes 1-3a is arranged at a portion above the portion where one end of the third inlet heat transfer tube at the bottom is arranged in the third inlet space 2-3.

[0056] The plurality of fourth return spaces 5-4 are respectively connected to the plurality of fourth inlet-side heat transfer tubes 1-4a, and are respectively connected to the plurality of fourth outlet-side heat transfer tubes 1-4b. That is, each of the plurality of fourth return spaces 5-4 is connected to one fourth inlet-side heat transfer tube among the plurality of fourth inlet-side heat transfer tubes 1-4a, and is connected to one fourth outlet-side heat transfer tube among the plurality of fourth outlet-side heat transfer tubes 1-4b. The plurality of fourth return spaces 5-4 include the fourth return space 17 at the uppermost side and the fourth return space 18 at the second uppermost side. The fourth return space 17 at the uppermost side is connected to the fourth inlet-side heat transfer tube at the uppermost side among the plurality of fourth inlet-side heat transfer tubes 1-4a. The fourth inlet-side heat transfer tube at the uppermost side is a flow path arranged at the uppermost side among the plurality of fourth inlet-side heat transfer tubes 1-4a, and one end of the fourth inlet-side heat transfer tube at the uppermost side connected to the fourth inlet space 2-4 is connected to the uppermost portion of the fourth inlet space 2-4. That is, one end of the other fourth inlet-side heat transfer tubes different from the fourth inlet-side heat transfer tube at the top among the plurality of fourth inlet-side heat transfer tubes 1-4a is arranged at a portion of the fourth inlet space 2-4 that is lower than the portion where one end of the fourth inlet-side heat transfer tube at the top is arranged. The fourth return space 18 at the second top is connected to the fourth inlet-side heat transfer tube at the second top among the plurality of fourth inlet-side heat transfer tubes 1-4a. The fourth inlet-side heat transfer tube at the second top is a flow path arranged at the second top next to the fourth inlet-side heat transfer tube at the top among the plurality of fourth inlet-side heat transfer tubes 1-4a. One end of the fourth inlet-side heat transfer tube at the second top that is connected to the fourth inlet space 2-4 is connected to one end of the fourth inlet-side heat transfer tube at the top and is connected to the portion at the second top.

[0057] The return header 170 also includes a first refrigerant tube 21, a second refrigerant tube 22, and a third refrigerant tube 23. A first connecting passage is formed inside the first refrigerant tube 21. The first connecting passage is connected to the first return space 6 at the bottom of the plurality of first return spaces 5-1, and is connected to the second return space 7 at the top of the plurality of second return spaces 5-2. A second connecting passage is formed inside the second refrigerant tube 22. The second connecting passage is connected to the second return space 11 at the bottom of the plurality of second return spaces 5-2, and is connected to the third return space 14 at the top and the third return space 15 at the top of the plurality of third return spaces 5-3. A third connecting passage is formed inside the third refrigerant tube 23. The third connecting passage is connected to the third return space 16 at the bottom of the plurality of third return spaces 5-3, and is connected to the fourth return space 17 at the top and the fourth return space 18 at the top of the plurality of fourth return spaces 5-4.

[0058] Operation of the heat exchanger 100 of Example 1

[0059] The heat exchanger 100 operates as an evaporator or a condenser. When operating as an evaporator, the flow divider 3 divides the inflowing refrigerant in such a way that the dryness of the gas-liquid two-phase refrigerant supplied to the first inlet space 2-1, the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 of the inlet header 120 is approximately the same.

[0060] Part of the liquid-phase refrigerant in the gas-liquid two-phase refrigerant supplied to the first inlet space 2-1 falls due to the influence of gravity. Therefore, the dryness of the gas-liquid two-phase refrigerant in the upper area of ​​the first inlet space 2-1 is greater than the dryness of the gas-liquid two-phase refrigerant in the lower area of ​​the first inlet space 2-1. The gas-liquid two-phase refrigerant supplied to the first inlet space 2-1 is supplied to a plurality of first inlet-side heat transfer tubes 1-1a, thereby flowing in the plurality of first inlet-side heat transfer tubes 1-1a. At this time, among the gas-liquid two-phase refrigerant supplied to the plurality of first inlet-side heat transfer tubes 1-1a, the dryness of the gas-liquid two-phase refrigerant in the first inlet-side heat transfer tubes arranged closer to the upper side is greater.

[0061] Similar to the gas-liquid two-phase refrigerant in the first inlet space 2-1, the gas-liquid two-phase refrigerant supplied to the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 has a higher dryness than the gas-liquid two-phase refrigerant in the upper side. The gas-liquid two-phase refrigerant supplied to the second inlet space 2-2, the third inlet space 2-3, and the fourth inlet space 2-4 is supplied to the plurality of second inlet-side heat transfer tubes 1-2a, the plurality of third inlet-side heat transfer tubes 1-3a, and the plurality of fourth inlet-side heat transfer tubes 1-4a. Therefore, similar to the gas-liquid two-phase refrigerant supplied to the plurality of first inlet-side heat transfer tubes 1-1a, the gas-liquid two-phase refrigerant supplied to the plurality of second inlet-side heat transfer tubes 1-2a has a higher dryness in the second inlet-side heat transfer tubes arranged closer to the upper side. Similarly, among the gas-liquid two-phase refrigerant supplied to the multiple third inlet side heat transfer tubes 1-3a, the gas-liquid two-phase refrigerant in the third inlet side heat transfer tubes arranged closer to the upper side has a higher dryness, and among the gas-liquid two-phase refrigerant supplied to the multiple fourth inlet side heat transfer tubes 1-4a, the gas-liquid two-phase refrigerant in the fourth inlet side heat transfer tubes arranged closer to the upper side has a higher dryness.

[0062] The air flowing outside the plurality of inlet-side heat transfer tubes 111a and the gas-liquid two-phase refrigerant flowing in the plurality of inlet-side heat transfer tubes 111a are in thermal contact with the plurality of inlet-side heat transfer tubes 111a, and thus heat is exchanged with each other through the plurality of inlet-side heat transfer tubes 111a. That is, the air flowing outside the plurality of inlet-side heat transfer tubes 111a is cooled by such heat exchange. The gas-liquid two-phase refrigerant flowing in the plurality of inlet-side heat transfer tubes 111a evaporates part of the liquid phase refrigerant in the gas-liquid two-phase refrigerant by such heat exchange, thereby increasing the dryness.

[0063] The gas-liquid two-phase refrigerant flowing through the plurality of inlet-side heat transfer tubes 111a is supplied to the plurality of first return spaces 5-1, the plurality of second return spaces 5-2, the plurality of third return spaces 5-3, and the plurality of fourth return spaces 5-4 of the return header 170. Specifically, the gas-liquid two-phase refrigerant flowing through a first inlet-side heat transfer tube among the plurality of first inlet-side heat transfer tubes 1-1a is supplied to the first return space connected to the first inlet-side heat transfer tube among the plurality of first return spaces 5-1. For example, the gas-liquid two-phase refrigerant flowing through the first inlet-side heat transfer tube at the bottom among the plurality of first inlet-side heat transfer tubes 1-1a is supplied to the first return space 6 at the bottom among the plurality of first return spaces 5-1.

[0064] Similar to the gas-liquid two-phase refrigerant flowing through the plurality of first inlet-side heat transfer tubes 1-1a, the gas-liquid two-phase refrigerant flowing through the plurality of second inlet-side heat transfer tubes 1-2a is respectively supplied to the plurality of second return spaces 5-2 of the return header 170. For example, the gas-liquid two-phase refrigerant flowing through the second inlet-side heat transfer tube at the uppermost side among the plurality of second inlet-side heat transfer tubes 1-2a is supplied to the second return space 7 at the uppermost side among the plurality of second return spaces 5-2. The gas-liquid two-phase refrigerant flowing through the second inlet-side heat transfer tube at the lowermost side among the plurality of second inlet-side heat transfer tubes 1-2a is supplied to the second return space 11 at the lowermost side among the plurality of second return spaces 5-2. The gas-liquid two-phase refrigerant flowing through the second lower second inlet-side heat transfer tubes 1-2a is supplied to the second lower second return space 12 among the plurality of second return spaces 5-2.

[0065] The gas-liquid two-phase refrigerant flowing through the plurality of third inlet-side heat transfer tubes 1-3a is respectively supplied to the plurality of third return spaces 5-3 of the return header 170. For example, the gas-liquid two-phase refrigerant flowing through the third inlet-side heat transfer tube at the uppermost side among the plurality of third inlet-side heat transfer tubes 1-3a is supplied to the third return space 14 at the uppermost side among the plurality of third return spaces 5-3. The gas-liquid two-phase refrigerant flowing through the third inlet-side heat transfer tube at the second upper side among the plurality of third inlet-side heat transfer tubes 1-3a is supplied to the third return space 15 at the second upper side among the plurality of third return spaces 5-3. The gas-liquid two-phase refrigerant flowing through the third inlet-side heat transfer tube at the lowermost side among the plurality of third inlet-side heat transfer tubes 1-3a is supplied to the third return space 16 at the lowermost side among the plurality of third return spaces 5-3.

[0066] The gas-liquid two-phase refrigerant flowing through the plurality of fourth inlet-side heat transfer tubes 1-4a is respectively supplied to the plurality of fourth return spaces 5-4 of the return header 170. For example, the gas-liquid two-phase refrigerant flowing through the fourth inlet-side heat transfer tube at the uppermost side among the plurality of fourth inlet-side heat transfer tubes 1-4a is supplied to the fourth return space 17 at the uppermost side among the plurality of fourth return spaces 5-4. The gas-liquid two-phase refrigerant flowing through the fourth inlet-side heat transfer tube at the second upper side among the plurality of fourth inlet-side heat transfer tubes 1-4a is supplied to the fourth return space 18 at the second upper side among the plurality of fourth return spaces 5-4.

[0067] Since the first lower side (lowest side) first return space 6 among the plurality of first return spaces 5-1 and the first upper side (upper side) second return space 7 among the plurality of second return spaces 5-2 are connected by the first refrigerant pipe 21, the gas-liquid two-phase refrigerant supplied to the lowermost first return space 6 among the plurality of first return spaces 5-1 and the gas-liquid two-phase refrigerant supplied to the uppermost second return space 7 among the plurality of second return spaces 5-2 are mixed. The mixed gas-liquid two-phase refrigerant is supplied from the lowermost first return space 6 among the plurality of first return spaces 5-1 to the lowermost first outlet heat transfer tube among the plurality of first outlet heat transfer tubes 1-1b connected to the plurality of first return spaces 5-1, and is supplied from the uppermost second return space 7 among the plurality of second return spaces 5-2 to the uppermost second outlet heat transfer tube among the plurality of second outlet heat transfer tubes 1-2b connected to the plurality of second return spaces 5-2.

[0068] Similarly, the gas-liquid two-phase refrigerant supplied to the second return space 11 at the bottom and the second lower second return space 12 among the plurality of second return spaces 5-2, and the third return space 14 at the top and the third return space 15 at the second upper side among the plurality of third return spaces 5-3, respectively, is mixed through the second refrigerant pipe 22. The gas-liquid two-phase refrigerant mixed through the second refrigerant pipe 22 is supplied to the second outlet heat transfer pipe at the bottom and the second lower second outlet heat transfer pipe connected to the plurality of second return spaces 5-2, and the third outlet heat transfer pipe at the top and the second upper third outlet heat transfer pipe connected to the plurality of third return spaces 5-3. The gas-liquid two-phase refrigerant supplied to the third return space 16 at the bottom among the plurality of third return spaces 5-3, the fourth return space 17 at the top and the second upper fourth return space 18 at the second upper side, respectively, is mixed through the third refrigerant pipe 23. The gas-liquid two-phase refrigerant mixed through the third refrigerant pipe 23 is supplied to the bottom third outlet heat transfer pipe connected to multiple third return spaces 5-3 and the top fourth outlet heat transfer pipe and the second top fourth outlet heat transfer pipe connected to multiple fourth return spaces 5-4.

[0069] The gas-liquid two-phase refrigerant supplied to a first circulation space different from the bottom first circulation space 6 among the plurality of first circulation spaces 5-1 is directly supplied to the first outlet heat transfer tube connected to the first circulation space among the plurality of first outlet heat transfer tubes 1-1b without being mixed with other gas-liquid two-phase refrigerants. The gas-liquid two-phase refrigerant supplied to a second circulation space different from the top second circulation space 7, the bottom second circulation space 11, and the second bottom second circulation space 12 among the plurality of second circulation spaces 5-2 is also directly supplied to the second outlet heat transfer tube connected to the second circulation space among the plurality of second outlet heat transfer tubes 1-2b. The gas-liquid two-phase refrigerant supplied to a third circulation space different from the third circulation space 14 at the top, the third circulation space 15 at the second top, and the third circulation space 16 at the bottom among the plurality of third circulation spaces 5-3 is also directly supplied to the third outlet heat transfer tube connected to the third circulation space among the plurality of third outlet heat transfer tubes 1-3b. The gas-liquid two-phase refrigerant supplied to a fourth circulation space different from the fourth circulation space 17 at the top and the fourth circulation space 18 at the second top among the plurality of fourth circulation spaces 5-4 is also directly supplied to the fourth outlet heat transfer tube connected to the fourth circulation space among the plurality of fourth outlet heat transfer tubes 1-4b.

[0070] The air flowing outside the multiple outlet heat transfer tubes 111b and the gas-liquid two-phase refrigerant flowing in the multiple outlet heat transfer tubes 111b are in thermal contact with the multiple outlet heat transfer tubes 111b, thereby exchanging heat with each other through the multiple outlet heat transfer tubes 111b. The air flowing outside the multiple outlet heat transfer tubes 111b is cooled by such heat exchange. The gas-liquid two-phase refrigerant flowing in the multiple outlet heat transfer tubes 111b evaporates part of the liquid phase refrigerant in the gas-liquid two-phase refrigerant by such heat exchange, thereby further improving the dryness. The gas-liquid two-phase refrigerant flowing through the multiple outlet heat transfer tubes 111b is supplied to the outlet header 140, and flows to the outside through the outlet space 4 and the outflow pipe 150.

[0071] Since the amount of refrigerant that can be vaporized in a refrigerant with a high gas phase ratio (high dryness) is small, the amount of latent heat used for heat exchange with the air is small. In other words, if the flow is not divided in a state where the gas phase and the liquid phase are uniform, the heat exchange capacity of the outlet heat transfer pipe 111b where the high dryness refrigerant flows is reduced accordingly, resulting in a decrease in the heat exchange amount as a heat exchanger. When the dryness of the gas-liquid two-phase refrigerant supplied to the outlet heat transfer pipe 111b is high, the amount of heat exchange with the air is reduced compared to when the dryness is low.

[0072] The heat exchanger 100 of this embodiment is provided with the first refrigerant tube 21, the second refrigerant tube 22, and the third refrigerant tube 23, so that the gas-liquid two-phase refrigerant with a higher dryness (for example, the refrigerant supplied to the second return space 7 at the uppermost side among the plurality of second return spaces 5-2) flowing through the plurality of inlet-side heat transfer tubes 111a can be mixed with the gas-liquid two-phase refrigerant with a lower dryness (for example, the refrigerant supplied to the first return space 6 at the lowermost side among the plurality of first return spaces 5-1). The heat exchanger 100 can supply the gas-liquid two-phase refrigerant with a uniform dryness to the plurality of outlet-side heat transfer tubes 111b by mixing the gas-liquid two-phase refrigerants with different dryness. The heat exchanger 100 allows the gas-liquid two-phase refrigerant with uniform dryness to flow through the plurality of outlet heat transfer tubes 111b, so that the gas-liquid two-phase refrigerant is divided into the outlet heat transfer tubes 111b in a state where the ratio of the gas phase to the liquid phase is uniform, thereby suppressing the reduction in the heat exchange capacity of the heat exchanger. In addition, the air flowing outside the outlet heat transfer tubes 111b can be appropriately cooled.

[0073] When operating as a condenser, the refrigerant flows in the opposite direction to when operating as an evaporator. That is, the heat exchanger 100 first supplies a gas-phase single-phase refrigerant, or a gas-liquid two-phase refrigerant with a sufficiently high dryness, to the outlet space 4 of the outlet header 140. The refrigerant supplied to the outlet space 4 is supplied to a plurality of outlet-side heat transfer tubes 111b and flows in the plurality of outlet-side heat transfer tubes 111b. At this time, since the dryness of the refrigerant supplied to the outlet space 4 is sufficiently high, it is not easily affected by gravity and causes uneven dryness. Therefore, the dryness of the refrigerants supplied to the plurality of outlet-side heat transfer tubes 111b is approximately equal.

[0074] The air flowing outside the plurality of outlet heat transfer tubes 111b and the refrigerant flowing in the plurality of outlet heat transfer tubes 111b are in thermal contact with the plurality of outlet heat transfer tubes 111b, thereby exchanging heat with each other through the plurality of outlet heat transfer tubes 111b. The refrigerant flowing in the plurality of outlet heat transfer tubes 111b is partially condensed by such heat exchange, thereby reducing the dryness. The air flowing outside the plurality of outlet heat transfer tubes 111b is heated by such heat exchange.

[0075] The refrigerant flowing through the plurality of outlet-side heat transfer tubes 111b is supplied to the return header 170, and is thus supplied to the plurality of spaces formed in the return header 170. At this time, since the first return space 6 at the bottom of the plurality of first return spaces 5-1 and the second return space 7 at the top of the plurality of second return spaces 5-2 are connected by the first refrigerant pipe 21, the refrigerant supplied to the first return space 6 at the bottom of the plurality of first return spaces 5-1 and the refrigerant supplied to the second return space 7 at the top of the plurality of second return spaces 5-2 are mixed. Similarly, the refrigerants supplied to the second return space 11 at the bottom and the second lower second return space 12 at the bottom of the plurality of second return spaces 5-2, and the third return space 14 at the top and the third return space 15 at the top of the plurality of third return spaces 5-3 are mixed through the second refrigerant pipe 22. The refrigerants supplied to the third return space 16 at the bottom among the plurality of third return spaces 5-3, the fourth return space 17 at the top among the plurality of fourth return spaces 5-4, and the fourth return space 18 at the second top are mixed through the third refrigerant pipe 23. Since the original dryness is substantially equal, the refrigerants supplied to the plurality of spaces have substantially equal dryness after being mixed in this way.

[0076] The refrigerant supplied to the plurality of spaces is supplied to the plurality of inlet-side heat transfer tubes 111a and flows through the plurality of inlet-side heat transfer tubes 111a. The refrigerant flowing through the plurality of inlet-side heat transfer tubes 111a and the air flowing outside the plurality of inlet-side heat transfer tubes 111a are in thermal contact with the plurality of inlet-side heat transfer tubes 111a, and thus heat is exchanged with each other through the plurality of inlet-side heat transfer tubes 111a. The refrigerant flowing through the plurality of inlet-side heat transfer tubes 111a is further condensed by such heat exchange, and thus the dryness is further reduced. The air flowing outside the plurality of inlet-side heat transfer tubes 111a is heated by such heat exchange. The gas-liquid two-phase refrigerant flowing through the plurality of inlet-side heat transfer tubes 111a is supplied to the splitter 3 through the first inlet space 2-1, the second inlet space 2-2, the third inlet space 2-3, the fourth inlet space 2-4 of the inlet header 120, and the inflow pipe 130, and flows from the splitter 3 to the outside.

[0077] As can be seen from the above, when the heat exchanger 100 is used as a condenser, even if the first refrigerant tube 21, the second refrigerant tube 22 and the third refrigerant tube 23 are provided in the return header 170, the dryness of the refrigerant can be appropriately reduced, so that it can work properly as a condenser.

[0078] Effects of the heat exchanger 100 of Example 1

[0079] The heat exchanger 100 of the first embodiment includes an inlet header 120, a plurality of inlet-side heat transfer tubes 111a, a plurality of outlet-side heat transfer tubes 111b, and a return header 170. A first inlet space 2-1 and a second inlet space 2-2 are formed inside the inlet header 120. The plurality of inlet-side heat transfer tubes 111a include a plurality of first inlet-side heat transfer tubes 1-1a connected to the first inlet space 2-1, and a plurality of second inlet-side heat transfer tubes 1-2a connected to the second inlet space 2-2. The plurality of outlet-side heat transfer tubes 111b include a plurality of first outlet-side heat transfer tubes 1-1b and a plurality of second outlet-side heat transfer tubes 1-2b. The return header 170 is formed with a plurality of first return spaces 5-1 that connect the plurality of first inlet-side heat transfer tubes 1-1a and the plurality of first outlet-side heat transfer tubes 1-1b, and a plurality of second return spaces 5-2 that connect the plurality of second inlet-side heat transfer tubes 1-2a and the plurality of second outlet-side heat transfer tubes 1-2b. The first return space 6 at the bottom of the plurality of first return spaces 5-1 is connected to the first inlet-side heat transfer tube at the bottom of the plurality of first inlet-side heat transfer tubes 1-1a. The second return space 7 at the top of the plurality of second return spaces 5-2 is connected to the second inlet-side heat transfer tube at the top of the plurality of second inlet-side heat transfer tubes 1-2a. The return header 170 is also formed with a first refrigerant tube 21 that connects the first return space 6 at the bottom with the second return space 7 at the top.

[0080] In addition, the heat exchanger 100 of Example 1 is further provided with a flow divider 3, which is used to supply the refrigerant in the gas-liquid two-phase state to the first inlet space 2-1 and the second inlet space 2-2. When the heat exchanger 100 supplies the refrigerant in the gas-liquid two-phase state to the first inlet space 2-1 and the second inlet space 2-2, the refrigerant supplied to the first inlet-side heat transfer tube closer to the upper side has a higher dryness, and the refrigerant supplied to the second inlet-side heat transfer tube closer to the upper side has a higher dryness. As a result, the dryness of the refrigerant flowing through the second inlet-side heat transfer tube at the uppermost side is sometimes greater than the dryness of the refrigerant flowing through the first inlet-side heat transfer tube at the lowermost side. Since the first refrigerant tube 21 is provided, the heat exchanger 100 can mix the refrigerant flowing through the second inlet-side heat transfer tube at the uppermost side with the refrigerant flowing through the first inlet-side heat transfer tube at the lowermost side, so that the gas-liquid two-phase refrigerant with uniform dryness can be supplied to the plurality of outlet-side heat transfer tubes 111b. The heat exchanger 100 allows the gas-liquid two-phase refrigerant having uniform dryness to flow through the plurality of outlet-side heat transfer tubes 111 b , thereby suppressing a decrease in the heat exchange amount of the heat exchanger.

[0081] Furthermore, the heat exchanger 100 of the first embodiment described above is provided with the flow divider 3, but the flow divider 3 may be omitted. Even when the flow divider 3 is omitted, the heat exchanger 100 can flow to the outlet side heat transfer tube in a state where the ratio of the gas phase to the liquid phase is uniform, thereby suppressing a decrease in the heat exchange amount as the heat exchanger.

[0082] In addition, the first refrigerant tube 21 of the heat exchanger 100 of the above-mentioned embodiment 1 mixes the refrigerants supplied to the two spaces formed in the return header 170, but it can also mix the refrigerants supplied to more than three spaces like the second refrigerant tube 22 and the third refrigerant tube 23. In this case, since the heat exchanger 100 diverts the gas phase and the liquid phase to the outlet side heat transfer tube in a uniform ratio, it is also possible to suppress the reduction in the heat exchange amount as a heat exchanger.

[0083] In addition, the number of inlet-side heat transfer tubes 111a of the heat exchanger 100 of Example 1 connected to the first inlet space 2-1 is less than the number of inlet-side heat transfer tubes connected to the second inlet space 2-2, the third inlet space 2-3 and the fourth inlet space 2-4. Therefore, the length of the first inlet space 2-1 in the vertical direction can be shorter than that of the second inlet space 2-2, the third inlet space 2-3 and the fourth inlet space 2-4. The first inlet space 2-1 at the top is the inlet space with the highest gas phase ratio, and is more susceptible to the influence of gravity and the phenomenon of uneven refrigerant dryness. Therefore, by shortening the length of the first inlet space 2-1 in the vertical direction, the uneven dryness of the refrigerant inside the first inlet space 2-1 can be reduced, thereby reducing the uneven dryness of the gas-liquid two-phase refrigerant supplied to the multiple first inlet-side heat transfer tubes 1-1a connected to the first inlet space 2-1.

[0084] Furthermore, although the plurality of outlet-side heat transfer tubes 111 b of the heat exchanger 100 of the first embodiment described above are arranged along the plurality of inlet-side heat transfer tubes 111 a , they may not be arranged along the plurality of inlet-side heat transfer tubes 111 a .

[0085] Example 2

[0086] Fig. 9 Schematic diagram of a heat exchanger 200 according to Embodiment 2. In the heat exchanger 200, the heat exchanger core 110 of the heat exchanger 100 according to Embodiment 1 is replaced by a plurality of inlet-side cores 210 and a plurality of outlet-side cores 220. The plurality of inlet-side cores 210 are formed by the plurality of inlet-side heat transfer tubes 111a and the plurality of inlet-side fins 112a. The plurality of outlet-side cores 220 are formed by the plurality of outlet-side heat transfer tubes 111b and the plurality of outlet-side fins 112b. The plurality of outlet-side cores 220 are arranged along other planes perpendicular to the plane along which the plurality of inlet-side cores 210 are arranged, and are not arranged along the plurality of inlet-side cores 210.

[0087] Furthermore, in the heat exchanger 200, the return header 170 of the heat exchanger 100 of the above-mentioned embodiment 1 is replaced with another header 230. The header 230 is formed with a plurality of first return spaces 5-1, a plurality of second return spaces 5-2, a plurality of third return spaces 5-3, and a plurality of fourth return spaces 5-4, similarly to the above-mentioned return header 170. Further, the header 230 is provided with a first refrigerant pipe 21, a second refrigerant pipe 22, and a third refrigerant pipe 23, which are respectively formed with a first connecting passage, a second connecting passage, and a third connecting passage, similarly to the above-mentioned return header 170.

[0088] The heat exchanger 200 performs the same operation as the heat exchanger 100 of the above-mentioned embodiment 1. The heat exchanger 200, like the heat exchanger 100 of the above-mentioned embodiment 1, also divides the gas phase and the liquid phase to the outlet side heat transfer tube in a uniform ratio when the plurality of outlet side core portions 220 are not arranged along the plurality of inlet side core portions 210, thereby suppressing the reduction in the heat exchange amount as the heat exchanger.

[0089] In addition, the above-mentioned return headers 170 and 230 form the first connecting path by providing the first refrigerant tube 21, but the first connecting path may be formed without using the first refrigerant tube 21. For example, the return header 170 may also form a first connecting path that connects the lowermost first return space 6 with the uppermost second return space 7 by forming recesses on the plate-like member 171 and the plate-like member 172, respectively. Similarly, in the return header 170, the recesses of the plate-like member 171 and the plate-like member 172 may also form a second connecting path that connects the lowermost second return space 11, the second lower second return space 12, the uppermost third return space 14, and the second upper third return space 15. Similarly, in the return header 170, the third connecting passage that connects the third return space 16 at the bottom, the fourth return space 17 at the top, and the fourth return space 18 at the second top can be formed by the recessed portions of the plate-shaped member 171 and the plate-shaped member 172. When such a return header is provided, the heat exchanger can also suppress a decrease in heat exchange amount.

[0090] The above embodiments are described, but the embodiments are not limited to the above contents. In addition, the above structural elements include: elements that can be easily thought of by those skilled in the art, substantially the same elements, and elements of the so-called equal range. In addition, the above structural elements can be appropriately combined. In addition, within the scope of the gist of the embodiments, the structural elements can be omitted, replaced, and changed in at least one of various ways.

[0091] Explanation of symbols

[0092] 100: Heat exchanger

[0093] 110: Heat exchanger core

[0094] 111a: Inlet side heat transfer tube

[0095] 111b: outlet side heat transfer tube

[0096] 112a: Inlet side fin

[0097] 112b: outlet side fin

[0098] 120: Inlet header

[0099] 130: Inflow pipe

[0100] 140: Export header

[0101] 150: Outflow pipe

[0102] 170: Return header

[0103] 1-1: The first heat exchange part

[0104] 1-2: Second heat exchange section

[0105] 1-3: The third heat exchange part

[0106] 1-4: The fourth heat exchange section

[0107] 2-1: First entrance space

[0108] 2-2: Second entrance space

[0109] 2-3: The third entrance space

[0110] 2-4: Fourth Entrance Space

[0111] 3: Shunt

[0112] 5-1: Multiple first return spaces

[0113] 5-2: Multiple second return spaces

[0114] 5-3: Multiple third-loop spaces

[0115] 5-4: Multiple fourth loop spaces

[0116] 6: The first return space at the bottom

[0117] 7: The second return space on the top

[0118] 11: The second return space at the bottom

[0119] 12: The second return space on the second lower side

[0120] 14: The third loop space at the top

[0121] 15: The third return space on the second upper side

[0122] 16: The third return space at the bottom

[0123] 17: The fourth loop space at the top

[0124] 18: The fourth return space on the second upper side

[0125] 21: First refrigerant pipe

[0126] 22: Second refrigerant pipe

[0127] 23: The third refrigerant pipe

[0128] 200: Heat exchanger

[0129] 210: Multiple inlet side cores

[0130] 220: Multiple outlet side cores

[0131] 230: Header

Claims

1. A heat exchanger, characterized in that: have: an inlet header having a plurality of inlet spaces formed therein, the plurality of inlet spaces comprising a first inlet space and a second inlet space adjacent to and below the first inlet space; a plurality of inlet-side heat transfer tubes, including a plurality of first inlet-side heat transfer tubes connected to the first inlet space and arranged in a vertical direction, and a plurality of second inlet-side heat transfer tubes connected to the second inlet space and arranged in a vertical direction; A return header having a plurality of return spaces formed therein, wherein the plurality of return spaces include a plurality of first return spaces arranged in a vertical direction and a plurality of second return spaces arranged in a vertical direction; as well as A plurality of outlet-side heat transfer tubes are connected to each of the plurality of return spaces by one or more and arranged in the vertical direction. The plurality of first inlet-side heat transfer tubes are respectively connected to the plurality of first return spaces, so that each of the plurality of first inlet-side heat transfer tubes is connected to one of the plurality of first return spaces, and each of the first inlet-side heat transfer tubes is not connected to other return spaces among the plurality of return spaces that are different from the one first return space. The plurality of second inlet-side heat transfer tubes are respectively connected to the plurality of second return spaces, so that each of the plurality of second inlet-side heat transfer tubes is connected to one of the plurality of second return spaces, and each of the second inlet-side heat transfer tubes is not connected to other return spaces among the plurality of return spaces that are different from the one second return space. A connecting passage is formed inside the return header, which connects the first return space at the bottom of the plurality of first return spaces with the second return space at the top of the plurality of second return spaces.

2. The heat exchanger according to claim 1, characterized in that: The total number of the plurality of return spaces is the same as the total number of the plurality of inlet-side heat transfer tubes.

3. The heat exchanger according to claim 1, characterized in that: The plurality of inlet-side heat transfer tubes are arranged along the plurality of outlet-side heat transfer tubes.

4. The heat exchanger according to claim 1, characterized in that: The plurality of entrance spaces include: an uppermost entrance space and other entrance spaces arranged below the uppermost entrance space. The number of the inlet-side heat transfer tubes connected to the uppermost inlet space among the plurality of inlet-side heat transfer tubes is smaller than the number of the inlet-side heat transfer tubes connected to the other inlet spaces among the plurality of inlet-side heat transfer tubes.

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