Heat exchanger, outdoor unit and air conditioning device

Abstract

The heat exchanger disclosed herein comprises a plurality of heat transfer tubes arranged side by side horizontally with a gap between them and having a flow path through which a refrigerant flows in a vertical direction, and a header having a cylindrical header tube extending in the direction in which the plurality of heat transfer tubes are arranged, the header tube having a first member having a top wall into which the lower ends of the plurality of heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other, and a second member having a bottom wall and two second side walls extending upward from both ends of the bottom wall and facing each other, wherein the distance between the two second side walls is narrower than the distance between the two first side walls, the height of the first side wall is greater than the height of the second side wall, the first side wall covers a portion of the second side wall to form a cylindrical shape, and the distance within the header tube from the lower ends of the heat transfer tubes to the bottom wall is longer than the distance between the two first side walls.

Description

[Technical field]

[0001] This technique relates to a heat exchanger, an outdoor unit, and an air conditioner, and in particular to a heat exchanger having a header that serves as a refrigerant distributor. [Background technology]

[0002] In recent years, in order to reduce the amount of refrigerant and improve the performance of heat exchangers, the heat transfer tubes in heat exchangers for air conditioners have been made thinner. As the heat transfer tubes become thinner, the number of branches in heat exchangers increases in order to suppress an increase in the pressure loss of the refrigerant. In order to accommodate this type of multi-branch distribution, heat exchangers have been developed in which a pair of headers that distribute the refrigerant are arranged in the height direction (up and down). In such heat exchangers, the longitudinal direction of cylindrical tubes with long sides is arranged horizontally (see, for example, Patent Document 1).

[0003] When a heat exchanger functions as an evaporator, a two-phase refrigerant, which is a mixture of liquid and gaseous refrigerant, flows into the tubes of the header located at the lower side in the height direction. At this time, in the header, the liquid refrigerant is likely to accumulate in the lower part of the tubes. When refrigerant accumulates in the heat exchanger, the amount of refrigerant circulating in the refrigerant circuit decreases. In order to maintain the amount of refrigerant circulating in the refrigerant circuit, the refrigerant circuit needs to have an amount of refrigerant in the circuit in advance that takes into account the amount of refrigerant accumulated in the heat exchanger, and the amount of refrigerant increases accordingly. Therefore, heat exchangers that aim to reduce the amount of refrigerant accumulated in the header have been proposed (for example, see Patent Document 2 and Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 08-005194 [Patent Document 2] Special Publication No. 2014-512502 [Patent Document 3] International Publication No. 2019 / 078066 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the heat exchanger can reduce the internal volume by reducing the cross-sectional area of ​​the tubes in the header to prevent the refrigerant from stagnating. However, simply reducing the cross-sectional area of ​​the tubes in the header to prevent the refrigerant from stagnating may increase the pressure loss of the refrigerant in the tubes, which may result in poor distribution of the refrigerant.

[0006] Therefore, the disclosed heat exchanger, outdoor unit, and air conditioning apparatus are intended to solve the problems described above, suppress deterioration of refrigerant distribution, and reduce the amount of refrigerant remaining in the heat exchanger while maintaining high heat exchange performance. [Means for solving the problem]

[0007] The heat exchanger according to the disclosure includes a plurality of heat transfer tubes arranged side by side at intervals along the horizontal direction and having a flow passage through which a refrigerant flows in the height direction, and a header having a cylindrical header tube extending along the direction in which the plurality of heat transfer tubes are arranged. The header tube has a first member having a top wall into which lower ends of the plurality of heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other, and a bottom wall and two second side walls extending upward from both ends of the bottom wall and facing each other. And in the header pipe, and a second member, wherein a distance between the two second side walls is narrower than a distance between the two first side walls, a height of the first side walls is higher than a height of the second side walls, a height of the second side walls is lower than a height of the first side walls, and the first side walls are spaced apart from the second side walls. of The header tube is covered with a cylindrical shape, and the distance from the lower end of the heat transfer tube to the bottom wall in the header tube is longer than the distance between the two first side walls. The bottom wall of the second member has a curved surface that forms an arc when viewed from the direction in which the heat transfer tubes are arranged, and the first member covers up to a part of the bottom wall so that the curved portion is exposed. It is something.

[0008] Moreover, an outdoor unit according to the present disclosure has the above-mentioned heat exchanger as an outdoor heat exchanger.

[0009] The air conditioner according to this disclosure comprises the above outdoor unit, and an indoor unit that has an indoor heat exchanger and a throttling device and conditions the air in a space to be air-conditioned. Effect of the Invention

[0010] According to the disclosed heat exchanger, outdoor unit, and air conditioner, the distribution header has a first member that forms the top surface and two side surfaces, and a second member that forms the bottom surface, and is configured in such a way that the first member covers the second member. By installing the second member as the bottom surface of the distribution header, the area in which liquid refrigerant accumulates at the bottom of the distribution header can be reduced, and the amount of refrigerant that accumulates can be reduced. In this case, by making the distribution header vertically long, the amount of refrigerant that accumulates can be reduced without reducing the cross-sectional area, and pressure loss can be reduced. Therefore, the amount of refrigerant that accumulates in the heat exchanger can be reduced while improving the distribution of the refrigerant flowing into the heat transfer tube and maintaining high heat exchange performance. Therefore, the amount of refrigerant in the entire refrigerant circuit can be reduced. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing the configuration of an air conditioning apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating the configuration of an outdoor unit 200 according to the first embodiment. [Diagram 3] FIG. 1 is a diagram illustrating a configuration of a heat exchanger 1000 according to a first embodiment. [Figure 4] 2 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the first embodiment when viewed from the X direction. [Diagram 5] 2 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the first embodiment when viewed from the Y direction. [Figure 6] 1A and 1B are diagrams illustrating the aspect ratio of a header pipe 1110 of a distribution header 1100 according to the first embodiment. [Figure 7] FIG. 1 is a diagram (part 1) for explaining the state of a refrigerant in a distribution header 1100 according to the first embodiment. [Figure 8]FIG. 2 is a second diagram for explaining the state of the refrigerant in the distribution header 1100 according to the first embodiment. [Figure 9] FIG. 3 is a third diagram for explaining the state of the refrigerant in the distribution header 1100 according to the first embodiment. [Figure 10] FIG. 4 is a fourth diagram for explaining the state of the refrigerant in the distribution header 1100 according to the first embodiment. [Figure 11] FIG. 11 is a diagram showing a part of a cross section of a heat exchanger 1000 according to a second embodiment when viewed from an X direction. [Figure 12] 11 is a diagram showing a part of a cross section of a heat exchanger 1000 according to a second embodiment when viewed from a Y direction. FIG. [Figure 13] FIG. 11 is a diagram (part 1) for explaining the state of the refrigerant in the distribution header 1100 according to the second embodiment. [Figure 14] FIG. 11 is a second diagram for explaining the state of the refrigerant in the distribution header 1100 according to the second embodiment. [Figure 15] FIG. 11 is a third diagram for explaining the state of the refrigerant in the distribution header 1100 according to the second embodiment. [Figure 16] FIG. 11 is a fourth diagram for explaining the state of the refrigerant in the distribution header 1100 according to the second embodiment. [Figure 17] 11 is a diagram showing a part of a cross section of a heat exchanger 1000 according to a third embodiment when viewed from a Y direction. FIG. [Figure 18] 13 is a diagram showing a part of a cross section of a heat exchanger 1000 according to a fourth embodiment when viewed from a Y direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a heat exchanger, an outdoor unit, and an air conditioner according to the embodiment will be described with reference to the drawings. In the following drawings, the same reference numerals are the same or equivalent, and are common throughout the entire embodiment described below. In addition, the size relationship of each component in the drawings may differ from the actual one. The form of the components shown in the entire specification is merely an example, and is not limited to the form described in the specification. In particular, the combination of components is not limited to the combination in each embodiment, and the components described in other embodiments can be applied to other embodiments. In addition, the upper side in the figure will be described as "upper" and the lower side as "lower". In addition, the high and low of pressure and temperature are not determined in relation to absolute values, but are determined relatively in the state, operation, etc. of the device. In addition, when there is no need to particularly distinguish or specify multiple similar devices that are distinguished by subscripts, the subscripts may be omitted.

[0013] Embodiment 1 <Air conditioner configuration> FIG. 1 is a diagram showing the configuration of an air conditioner according to the first embodiment. Here, an air conditioner will be described as an example of a refrigeration cycle device. As shown in FIG. 1, the air conditioner according to the first embodiment has an outdoor unit 200, an indoor unit 100, and two refrigerant pipes 300. The compressor 210, the four-way valve 220, and the outdoor heat exchanger 230 of the outdoor unit 200, and the indoor heat exchanger 110 and the throttling device 120 of the indoor unit 100 are connected by refrigerant pipes 300 to form a refrigerant circuit. Here, the air conditioner according to the first embodiment is assumed to have one outdoor unit 200 and one indoor unit 100 connected by piping. However, the number of connected units is not limited to this.

[0014] The indoor unit 100 is a device that is installed in a space to be air-conditioned and performs air conditioning. The indoor unit 100 has an indoor heat exchanger 110 and a throttling device 120 that constitute a refrigerant circuit, as well as an indoor blower 130. The throttling device 120 is a device that has an expansion valve that reduces the pressure of the refrigerant and expands it. For example, when the throttling device 120 is configured as an electronic expansion valve, it adjusts the opening degree based on instructions from a control device 400, which will be described later. The indoor heat exchanger 110 is a load-side heat exchanger that exchanges heat between the air in the room, which is the space to be air-conditioned, and the refrigerant. For example, during heating operation, the indoor heat exchanger 110 functions as a condenser and condenses and liquefies the refrigerant. During cooling operation, the indoor heat exchanger 110 functions as an evaporator and evaporates and vaporizes the refrigerant. The indoor blower 130 passes indoor air through the indoor heat exchanger 110 and supplies the air that has passed through the indoor heat exchanger 110 to the room. Here, the indoor heat exchanger 110 is described as directly exchanging heat between the refrigerant and the indoor air, but is not limited to this. For example, the indoor heat exchanger 110 may exchange heat between the refrigerant and water via the medium of water, and the water may exchange heat with the indoor air.

[0015] FIG. 2 is a diagram for explaining the configuration of the outdoor unit 200 according to the first embodiment. The outdoor unit 200 is a device installed outside the space to be air-conditioned. Here, the outdoor unit 200 according to the first embodiment is, for example, a top-flow type device having an outlet of an outdoor blower 280 at the center of the upper part of the housing. As shown in FIG. 1, the outdoor unit 200 according to the first embodiment has a compressor 210, a four-way valve 220, an outdoor heat exchanger 230, an auxiliary heat exchanger 240, a refrigerant amount control valve 250, a bypass pipe 260, and an accumulator 270 as devices constituting a refrigerant circuit. In addition, the outdoor unit 200 has an outdoor blower 280. The compressor 210 compresses the refrigerant that is sucked in and discharges it. The compressor 210 is, for example, a scroll compressor, a reciprocating compressor, or a vane compressor. Here, the air conditioner in the first embodiment has, for example, an inverter device (not shown) and can arbitrarily change the drive frequency of the power supplied to the compressor 210. By changing the drive frequency, the motor (not shown) of the compressor 210 can change the rotation speed, and the drive capacity of the compressor 210 can be changed.

[0016] The four-way valve 220 serving as the refrigerant flow switching device is, for example, a valve that switches the flow of the refrigerant depending on whether the operation is cooling or heating. When the heating operation is performed, the four-way valve 220 connects the discharge side of the compressor 210 to the indoor heat exchanger 110 and also connects the suction side of the compressor 210 to the outdoor heat exchanger 230. When the cooling operation is performed, the four-way valve 220 connects the discharge side of the compressor 210 to the outdoor heat exchanger 230 and also connects the suction side of the compressor 210 to the indoor heat exchanger 110. Here, the case where the four-way valve 220 is used is illustrated, but the flow switching device is not limited to this. The flow switching device may be, for example, a combination of a plurality of two-way valves.

[0017] The outdoor heat exchanger 230 exchanges heat between the refrigerant and the outdoor air. Here, the outdoor heat exchanger 230 of the first embodiment functions as an evaporator during heating operation, evaporating and vaporizing the refrigerant. On the other hand, during cooling operation, the outdoor heat exchanger 230 functions as a condenser, condensing and liquefying the refrigerant. As shown in FIG. 1, the outdoor heat exchanger 230 has two heat exchangers, 1000A and 1000B. In the refrigerant circuit, the heat exchanger 1000A and the heat exchanger 1000B are connected by piping so as to be parallel to each other. Details of the heat exchanger 1000 (the heat exchanger 1000A and the heat exchanger 1000B) will be described later. Here, the outdoor heat exchanger 230 is described as exchanging heat between the refrigerant and the outdoor air, but it may exchange heat between another external fluid and the refrigerant. Furthermore, when driven, the outdoor blower 280 causes air from outside the outdoor unit 200 to pass through the outdoor heat exchanger 230 and form a flow of air that flows out from within the outdoor unit 200 .

[0018] The auxiliary heat exchanger 240 has, for example, a double pipe or a plate heat exchanger. The auxiliary heat exchanger 240 supercools the refrigerant flowing out from the outdoor heat exchanger 230 during cooling operation. The auxiliary heat exchanger 240 is a refrigerant-to-refrigerant heat exchanger that exchanges heat between the refrigerant flowing out from the outdoor heat exchanger 230 and flowing through the main refrigerant circuit toward the indoor heat exchanger 110 and the refrigerant that has passed through the bypass piping 260 and the refrigerant amount control valve 250. The bypass piping 260 is a piping that forms a bypass flow path. The bypass flow path is a flow path in which, during cooling operation, a part of the refrigerant that has passed through the main refrigerant circuit side of the auxiliary heat exchanger 240 branches off, passes through the refrigerant amount control valve 250 and the bypass flow path side of the auxiliary heat exchanger 240, and flows into a piping on the refrigerant inlet side of the accumulator 270. The refrigerant amount control valve 250 is a refrigerant amount control device that is disposed in the bypass piping 260 and adjusts the amount of the refrigerant passing through the bypass piping 260. At this time, the refrigerant amount regulating valve 250 reduces the pressure of a portion of the refrigerant that has passed through the auxiliary heat exchanger 240 and branched off, and causes the refrigerant to pass through the bypass flow path side of the auxiliary heat exchanger 240 .

[0019] The accumulator 270 is disposed on the suction side of the compressor 210. The accumulator 270 passes a gaseous refrigerant (hereinafter referred to as a gas refrigerant) and stores a liquid refrigerant (hereinafter referred to as a liquid refrigerant).

[0020] The control device 400 controls the devices of the air conditioner. The control device 400 controls, for example, the throttling device 120, the compressor 210, the refrigerant amount control valve 250, and the like. The control device 400 can be configured with hardware such as a circuit device that realizes its functions. It can also be configured with a calculation device having a microcomputer, CPU, and the like, and software. The calculation device executes and processes the software to realize control.

[0021] <Air conditioner operation> Next, the operation of each device of the air conditioner will be described based on the flow of the refrigerant. First, the operation of each device of the refrigerant circuit in heating operation will be described based on the flow of the refrigerant. During heating operation, the control device 400 closes the refrigerant amount control valve 250. The solid arrows in FIG. 1 indicate the flow of the refrigerant in heating operation. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. While passing through the indoor heat exchanger 110, the gas refrigerant condenses and liquefies by, for example, exchanging heat with the air in the space to be air-conditioned. The condensed and liquefied refrigerant passes through the throttling device 120. The refrigerant is decompressed when passing through the throttling device 120. The refrigerant decompressed in the throttling device 120 to a gas-liquid two-phase state passes through the auxiliary heat exchanger 240 and the outdoor heat exchanger 230. Here, since the refrigerant amount control valve 250 is closed, no heat exchange occurs between the refrigerants in the auxiliary heat exchanger 240. In the outdoor heat exchanger 230, the refrigerant evaporates by exchanging heat with the outdoor air sent from the outdoor blower 280, and the gasified refrigerant passes through the four-way valve 220 and the accumulator 270, and is sucked back into the compressor 210. In this manner, the refrigerant in the air conditioner circulates to perform air conditioning related to heating.

[0022] Next, the cooling operation will be described. During the cooling operation, the control device 400 adjusts the refrigerant amount adjustment valve 250 to pass a part of the refrigerant passing through the main refrigerant circuit through the bypass piping 260. The dotted arrows in FIG. 1 indicate the flow of the refrigerant during the cooling operation. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230. The refrigerant then passes through the outdoor heat exchanger 230 and exchanges heat with the outdoor air supplied by the outdoor blower 280, whereby it is condensed and liquefied. A part of the refrigerant that passed through the main refrigerant circuit side of the auxiliary heat exchanger 240 passes through the bypass piping 260, is decompressed at the refrigerant amount adjustment valve 250, and becomes a low-temperature and low-pressure refrigerant, which passes through the bypass piping side of the auxiliary heat exchanger 240. Therefore, heat exchange between the refrigerants is performed, and the refrigerant that passed through the main refrigerant circuit side of the auxiliary heat exchanger 240 is supercooled. The liquefied refrigerant passes through the throttling device 120. Here, the refrigerant is decompressed and becomes a two-phase gas-liquid state when passing through the expansion device 120. The refrigerant that has been decompressed and become a two-phase gas-liquid state by the expansion device 120 passes through the indoor heat exchanger 110. Then, in the indoor heat exchanger 110, the refrigerant evaporates, for example, by exchanging heat with the air in the space to be air-conditioned, and the gasified refrigerant passes through the four-way valve 220 and is sucked back into the compressor 210. In this manner, the refrigerant in the air conditioner circulates to perform air conditioning related to cooling.

[0023] <Configuration of heat exchanger 1000> 3 is a diagram illustrating the configuration of the heat exchanger 1000 according to the first embodiment. The outdoor heat exchanger 230 has a corrugated fin tube type heat exchanger 1000 of a parallel piping type. Hereinafter, the up-down direction in the heat exchanger 1000 is defined as the Z direction (height direction). A direction perpendicular to the Z direction is defined as the horizontal direction. In addition, in the horizontal direction, a certain direction is defined as the X direction (vertical horizontal direction), and a direction perpendicular to the X direction is defined as the Y direction (horizontal horizontal direction).

[0024] As described above, the outdoor heat exchanger 230 of the outdoor unit 200 has two heat exchangers 1000 (heat exchanger 1000A and heat exchanger 1000B). The heat exchanger 1000A and the heat exchanger 1000B are connected in parallel to each other by piping in a refrigerant circuit. However, the number and form of connections in the refrigerant circuit of the first embodiment are not limited to this.

[0025] Each heat exchanger 1000 has two distribution headers 1100 (a distribution header 1100A and a distribution header 1100B), a turn-up header 1200, a plurality of heat transfer tubes 1300, and a plurality of corrugated fins 1400.

[0026] In the heat exchanger 1000 of the outdoor heat exchanger 230 in the first embodiment, a pair of headers consisting of two distribution headers 1100 and a turn-back header 1200 are arranged separately above and below in the Z direction. For example, in the outdoor unit 200, devices such as the compressor 210 are installed on the lower side of the outdoor unit 200. Therefore, due to piping connections and the like, the turn-back header 1200 is located on the upper side, and the two distribution headers 1100 serving as refrigerant distributors are arranged in positions below the turn-back header 1200.

[0027] A plurality of heat transfer tubes 1300 are arranged in line along the Y direction between the two distribution headers 1100 and the turn-back header 1200. As described later, the heat transfer tubes 1300 in the first embodiment have a flattened cross section. Here, a group of a plurality of heat transfer tubes 1300 is arranged in two rows, with the flat surfaces facing each other perpendicular to the distribution header 1100 and the turn-back header 1200 and parallel to each other. The group of heat transfer tubes 1300 in one row is connected to one distribution header 1100.

[0028] The distribution header 1100, which serves as a refrigerant distributor, is connected to other devices constituting the refrigeration cycle device by piping, and the refrigerant, which is a fluid that serves as a heat exchange medium, flows in and out, and the refrigerant is branched or merged. The distribution header 1100 has a header pipe 1110 (header pipe 1110A and header pipe 1110B) and a refrigerant inlet / outlet pipe 1120 (refrigerant inlet / outlet pipe 1120A and refrigerant inlet / outlet pipe 1120B). The header pipe 1110 is a long cylindrical pipe. The distribution header 1100 also has a refrigerant inlet / outlet pipe 1120 through which the refrigerant from the outside flows in and out. Here, the longitudinal direction of the header pipe 1110 is assumed to be along the Y direction, which is the arrangement direction of the multiple heat transfer pipes 1300. The structure of the distribution header 1100 will be further described later.

[0029] The turn-back header 1200 also functions as a bridge, joining the refrigerant flowing in from the group of heat transfer tubes 1300 in one row and branching it out to the group of heat transfer tubes 1300 in the other row.

[0030] The heat transfer tube 1300 in the first embodiment has a flat cross section, and the outer surface on the long side of the flat shape along the depth direction, which is the air flow direction, is flat, and the outer surface on the short side perpendicular to the long side is curved. The heat transfer tube 1300 in the first embodiment is a multi-hole flat heat transfer tube having a plurality of holes that serve as a refrigerant flow path inside the tube. In the first embodiment, the holes of the heat transfer tube 1300 are formed facing the Z direction to serve as a flow path between the distribution header 1100 and the turn-back header 1200. As described above, the heat transfer tubes 1300 are arranged at equal intervals in the X direction with the outer surfaces on the long sides facing each other. When manufacturing the heat exchanger 1000 of the outdoor heat exchanger 230 in the first embodiment, each heat transfer tube 1300 is inserted into an insertion hole (not shown) of the distribution header 1100 and the turn-back header 1200, and is brazed and joined. As described above, since the distribution header 1100 is disposed on the lower side, each heat transfer tube 1300 is inserted into the top surface of the distribution header 1100 and joined to a top wall 1111B described later. For example, a brazing material containing aluminum is used for brazing. This allows the distribution header 1100 and the turn-back header 1200 to communicate with the inside of each heat transfer tube 1300.

[0031] Corrugated fins 1400 are arranged between the flat surfaces of the arranged heat transfer tubes 1300 facing each other. The corrugated fins 1400 are arranged to increase the heat transfer area between the refrigerant and the outside air. The corrugated fins 1400 are formed by corrugating a plate material, and folding the plate material into a corrugated shape by repeated mountain folds and valley folds, forming an accordion-like shape. Here, the folded portions due to the unevenness formed by the corrugated shape become the apexes of the corrugated shape. In the first embodiment, the apexes of the corrugated fins 1400 are aligned along the Z direction. The corrugated fins 1400 are in surface contact with the apexes of the corrugated shape and the flat surfaces of the heat transfer tubes 1300. The contact portions are brazed and joined by a brazing material. The plate material of the corrugated fins 1400 is made of, for example, an aluminum alloy. A brazing material layer is clad on the surface of the plate material. The clad brazing material layer is based on, for example, an aluminum-silicon-based brazing material containing aluminum.

[0032] Fig. 4 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the first embodiment when viewed from the X direction. Fig. 5 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the first embodiment when viewed from the Y direction. The header pipe 1110 of the distribution header 1100 is a refrigerant distribution pipe having a long tubular shape. The header pipe 1110 has a first member 1111, a second member 1112, and a cover 1113.

[0033] 4 serves as a lid that closes the openings at both ends of the tube formed by combining the first member 1111 and the second member 1112, and separates the space inside the tube from the space outside the tube. The lid 1113 is joined to the first member 1111 and the second member 1112 at both ends of the tube. Of the two lids 1113, one lid 1113 has the refrigerant inlet / outlet pipe 1120 described above.

[0034] The first member 1111 is an inverted U-shaped semi-open member that serves as the top surface and flat side surface of the header tube 1110, which is a long tube extending in the Y direction. The first member 1111 has a first side wall 1111A and a top wall 1111B. The top wall 1111B is a wall into which the heat transfer tubes 1300 are inserted and joined. As shown in FIG. 5, the top wall 1111B of the first embodiment is a wall having a curved surface, and forms an arc shape when the heat exchanger 1000 is viewed from the Y direction. The two first side walls 1111A extend downward from first connection portions 1111C that are connection portions at both ends of the top wall 1111B, and serve as walls that face each other. When the heat exchanger 1000 is viewed from the Y direction, each of the first side walls 1111A has a shape in which a lower end first side wall lower end 1111D, which is the lower end of the first side wall 1111A, is bent in a direction in which the distance between the walls becomes shorter. Therefore, each of the first side walls 1111A covers up to a part of a bottom wall 1112B of the second member 1112 described later, and can support the second member 1112 by embracing it. In addition, the joint area between the inner surface of the first side wall lower end 1111D and the outer surface of the bottom wall 1112B can be increased.

[0035] The second member 1112 is a member forming the bottom surface in the header pipe 1110 which is cylindrical. The second member 1112 has a second side wall 1112A and a bottom wall 1112B. The bottom wall 1112B is the wall forming the bottom surface of the header pipe 1110. As shown in FIG. 5, the bottom wall 1112B of the first embodiment is a wall having a curved surface and forms an arc shape when the heat exchanger 1000 is viewed from the Y direction. The two second side walls 1112A extend upward from second connection portions 1112C which are connection portions at both ends of the bottom wall 1112B and become walls facing each other. The distance between the two second side walls 1112A is narrower than the distance between the two first side walls 1111A. Also, the height of each second side wall 1112A is lower than the height of the first side wall 1111A.

[0036] Here, the second member 1112 is installed in the space formed by the first side wall 1111A and the top wall 1111B of the first member 1111 and joined to the first member 1111. Therefore, a part of the inner wall surface of the first side wall 1111A of the first member 1111 and an outer wall surface of a part of the second side wall 1112A and the bottom wall 1112B of the second member 1112 are joined. By installing the second member 1112 in the space formed by the first side wall 1111A and the top wall 1111B of the first member 1111, as shown in FIG. 5, in the pipe of the header pipe 1110, the lower part becomes narrower by the amount of the second member 1112.

[0037] Also, as shown in FIG. 5, let the bending radius at the first connection portion 1111C of the first member 1111 be R1 and the bending radius at the second connection portion 1112C of the second member 1112 be R2. At this time, the bending radius R1 and the bending radius R2 are in the relationship of R2 < R1. By reducing the bending radius R2 in the second member 1112 and making the volume in the lower part of the header pipe 1110 smaller, the retention of the liquid refrigerant can be reduced.

[0038] Furthermore, as described above, the top wall 1111B of the first member 1111 and the bottom wall 1112B of the second member 1112 form an arc shape when viewed from the Y direction. The radius of the arc of the bottom wall 1112B is larger than the radius of the arc of the top wall 1111B. Therefore, the curve of the bottom wall 1112B is gentler and closer to a straight line. This reduces the volume of the lower part of the header pipe 1110.

[0039] FIG. 6 is a diagram for explaining the aspect ratio of the header tube 1110 of the distribution header 1100 according to the first embodiment. In the distribution header 1100 according to the first embodiment, in the space inside the header tube 1110, the distance H in the Z direction between the heat transfer tube lower end 1310, which is the lower end of the heat transfer tube 1300, and the bottom wall 1112B is longer than the distance W in the width direction between the two first side walls 1111A. For this reason, as shown in FIG. 5, the header tube 1110 of the distribution header 1100 has a long, flat shape with a different aspect ratio, that is, a long vertical length (length in the Z direction) and a short horizontal length (length in the X direction) when viewed from the X direction. For example, in FIG. 5, the aspect ratio (vertical length / horizontal length) of the header tube 1110 of the distribution header 1100 is approximately 1.41 when viewed from the outer surface of the tube. Also, the aspect ratio is approximately 1.47 when viewed from the inner surface of the tube. However, the aspect ratio of the header pipe 1110 is not limited to the ratio shown in FIG. 5. For example, when the distribution deviation is less than 30%, it can be said that there is little bias in the refrigerant distribution. As a result of trials, it was found that the effect of refrigerant distribution is effective when the aspect ratio of the header pipe 1110 is in the range of 1<aspect ratio (length / width)≦2.4 as shown in FIG. 6, and therefore the aspect ratio is effective when this range is satisfied. In particular, it is found that it is more desirable for the aspect ratio of length / width in the space inside the pipe to be 1.2 or more and 2 or less. This range is effective in terms of both good refrigerant distribution and suppression of an increase in stagnant refrigerant.

[0040] 7 to 10 are diagrams (part 1) to (part 4) for explaining the state of the refrigerant in the distribution header 1100 according to the first embodiment. FIG. 7 to FIG. 10 are schematic diagrams showing the first member 1111 and the second member 1112 of the distribution header 1100 and the heat transfer tube 1300. As described above, when the heat exchanger 1000 functions as an evaporator, the refrigerant in a gas-liquid two-phase state flows into the distribution header 1100. In the tube of the distribution header 1100, due to gravity and other factors, the gas refrigerant in the gas-liquid two-phase state is more abundant at the top and the liquid refrigerant is more abundant at the bottom. The liquid refrigerant forms a wavy flow in the tube of the distribution header 1100. In FIG. 7 to FIG. 10, the positional relationship between the liquid refrigerant collected at the bottom and the lower end 1310 of the heat transfer tube 1300 is represented as a liquid level 2000. However, the liquid level 2000 is a virtual surface, and in reality, as shown by the liquid level 2000 in Figs. 7 to 10, the boundary surface between the gas refrigerant and the liquid refrigerant is not fixed.

[0041] Fig. 7 is a diagram showing the state of the refrigerant as viewed from the Y direction in the distribution header 1100 according to the first embodiment, in which the distance H in the Z direction between the heat transfer tube lower end 1310 and the bottom wall 1112B is longer than the distance W in the X direction between the two first side walls 1111A. Fig. 8 is a diagram showing the state of the refrigerant as viewed from the X direction in Fig. 7. Fig. 9 is a diagram showing the state of the refrigerant as viewed from the Y direction in the distribution header 1100 according to the first embodiment, in which the cross-sectional area is the same as that of the distribution header 1100 in Fig. 7, but the distance H is shorter than the distance W. Fig. 10 is a diagram showing the state of the refrigerant as viewed from the X direction in Fig. 9.

[0042] When the distance H is shorter than the distance W, the distance between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the liquid level 2000 becomes closer as shown in Fig. 9. Therefore, as shown in Fig. 10, a lot of liquid refrigerant passes through the heat transfer tube 1300 close to the refrigerant inlet / outlet tube 1120 on the refrigerant inflow side, and there are parts in the tube where the liquid refrigerant is less at positions away from the refrigerant inlet / outlet tube 1120. Therefore, in the header tube 1110 of the distribution header 1100, the change in the liquid level 2000 in the Y direction becomes large, and in the heat transfer tube 1300 that is not close to the refrigerant inlet / outlet tube 1120, less liquid refrigerant passes through the heat transfer tube 1300. Therefore, the ratio of gas refrigerant to liquid refrigerant becomes biased depending on the position of the heat transfer tube 1300.

[0043] On the other hand, when the distance H is longer than the distance W, as shown in Fig. 7, the distance between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the liquid level 2000 becomes greater than in the case of Fig. 9. For this reason, the liquid refrigerant that did not pass through the heat transfer tubes 1300 close to the refrigerant inlet / outlet pipe 1120 reaches a position away from the refrigerant inlet / outlet pipe 1120, so that the change in the liquid level 2000 in the Y direction in the header tube 1110 of the distribution header 1100 becomes smaller. Therefore, the liquid refrigerant can pass even in the heat transfer tubes 1300 that are not close to the refrigerant inlet / outlet pipe 1120, and the ratio of gas refrigerant and liquid refrigerant passing through each heat transfer tube 1300 can be made more uniform.

[0044] As described above, according to the heat exchanger 1000 in Embodiment 1, the distribution header 1100 has a first member 1111 that forms the top surface and two side surfaces, and a second member 1112 that forms the bottom surface, and is configured such that the first member 1111 covers the second member 1112. In the semi-open space formed by the first member 1111, by installing the second member 1112 as the bottom surface of the distribution header 1100, the region where the liquid refrigerant stays at the lower part of the distribution header 1100 can be reduced, and the amount of the staying refrigerant can be decreased. At this time, the distribution header 1100 has a shape such that the distance H between the lower end 1310 of the heat transfer tube of the heat transfer tube 1300 and the bottom wall 1112B is longer than the distance W between the two first side walls 1111A. By making the distribution header 1100 vertically long, in the distribution header 1100, by reducing the lower region, it is possible to reduce the pressure loss without reducing the cross-sectional area, unlike the case of simply reducing the pipe diameter. Therefore, it is possible to reduce the amount of refrigerant staying in the heat exchanger 1000 while improving so that the distribution bias of the refrigerant flowing into each heat transfer tube 1300 is reduced. Accordingly, the amount of refrigerant in the entire refrigerant circuit can be reduced.

[0045] Further, the first side wall 1111A of the first member 1111 is configured to be bent in a direction in which the lower ends 1111D of the opposing first side walls are brought closer to each other. For this reason, the first side wall 1111A covers a part of the outer surface of the bottom wall 1112B of the second member 1112 at the lower end 1111D of the first side wall 1111A, and holds the second member 1112, so that the joint area with the second member 1112 can be increased.

[0046] Furthermore, the bending radius R2 of the second connection portion 1112C and the bending radius R1 of the first connection portion 1111C are shaped such that R2 < R1. Also, the radius of the arc in the bottom wall 1112B of the second member 1112 is made larger than the radius of the arc in the top wall 1111B of the first member 1111. Thereby, in the distribution header 1100, the lower region can be reduced.

[0047] Embodiment 2. Fig. 11 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the second embodiment when viewed from the X direction. Fig. 12 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the second embodiment when viewed from the Y direction. In Figs. 11 and 12, members and the like having the same reference numerals as those in Figs. 4 and 5 perform the same functions and operations as those described in the first embodiment.

[0048] In FIG. 11, the distribution header 1100 in the heat exchanger 1000 of the second embodiment is a double-structure refrigerant distributor having an outer pipe 1110C and an inner pipe 1120C. The outer pipe 1110C is a pipe formed by combining a first member 1111 and a second member 1112, similar to the header pipe 1110 described in the first embodiment. On the other hand, the inner pipe 1120C is a long pipe that is installed inside the outer pipe 1110C along the outer pipe 1110C. Although not particularly limited, in the distribution header 1100 of the second embodiment, the refrigerant inlet / outlet pipe 1120 is integrated with the inner pipe 1120C.

[0049] Here, the positional relationship between the outer pipe 1110C and the inner pipe 1120C of the distribution header 1100 in the second embodiment will be described. As shown in Fig. 12, the dimensional centerline of the outer pipe 1110C in the Z direction is defined as line EE, and the dimensional centerline of the inner pipe 1120C in the Z direction is defined as line FF. In this case, the FF line is located lower than the EE line in the Z direction. By positioning the inner pipe 1120C at the bottom in the space inside the outer pipe 1110C, it is possible to reduce the area where liquid refrigerant is likely to stagnate.

[0050] The inner tube 1120C has an orifice 1121 which serves as a refrigerant outflow hole. The refrigerant flowing out from the orifice 1121 is sprayed into the space between the inner tube 1120C and the outer tube 1110C, and flows from the outer tube 1110C into the heat transfer tube 1300. The gas-liquid two-phase refrigerant flowing into the inside of the inner tube 1120C from the refrigerant inlet / outlet tube 1120 is agitated when flowing out from the orifice 1121 into the space between the inner tube 1120C and the outer tube 1110C. Therefore, the liquid refrigerant and the gas refrigerant are in a nearly homogenous state. By making the refrigerant flow ratio of the refrigerant passing through the multiple heat transfer tubes 1300 more uniform, the heat exchange performance of the heat exchanger 1000 is improved.

[0051] Here, the orifice 1121 in the second embodiment is provided not directly below the inner pipe 1120C but obliquely below the inner pipe 1120C in a direction such that the gas-liquid two-phase refrigerant is sprayed onto the leeward side of the air passing through the heat exchanger 1000.

[0052] As described above, the heat transfer tube 1300 is a multi-hole flat heat transfer tube. Therefore, the heat transfer tube 1300 has a plurality of flow paths along the X direction, which is the direction in which air passes. By ejecting the gas-liquid two-phase refrigerant from the orifice 1121 to the leeward side, as shown by the solid arrow in FIG. 12, a gas-rich refrigerant having a higher ratio of gas refrigerant in the gas-liquid two-phase refrigerant is supplied to the leeward flow path of the heat transfer tube 1300. On the other hand, as shown by the dotted arrow in FIG. 12, a liquid-rich refrigerant having a higher ratio of liquid refrigerant in the gas-liquid two-phase refrigerant is supplied to the windward flow path of the heat transfer tube 1300. Therefore, a large amount of liquid refrigerant can be distributed to the windward side where the temperature difference between the refrigerant and the air is large, and the heat transfer performance can be improved.

[0053] Moreover, the orifice 1121 ejects the gas-liquid two-phase refrigerant into the lower region of the annular flow path, and the force of the ejection prevents the liquid refrigerant from accumulating. This allows for a reduction in the amount of refrigerant used. Furthermore, the orifice 1121 is located at a position S in the Z direction that is higher than a position T of the second side wall upper end 1112D, which is the upper end of the second side wall 1112A of the second member 1112 of the outer tube 1110C. This allows the gas-liquid two-phase refrigerant to be ejected from the orifice 1121 without reducing the force, and prevents the liquid refrigerant from accumulating.

[0054] 13 to 16 are diagrams (part 1) to (part 4) illustrating the state of the refrigerant in the distribution header 1100 according to the second embodiment. Figs. 13 to 16 diagrammatically show the outer tube 1110C (first member 1111 and second member 1112), the inner tube 1120C, and the heat transfer tube 1300 of the distribution header 1100. The liquid level 2000 is a noodle similar to that described in the first embodiment.

[0055] Fig. 13 is a diagram showing the state of the refrigerant as viewed from the Y direction in the distribution header 1100 according to the second embodiment, in which the distance H in the Z direction between the heat transfer tube lower end 1310 and the bottom wall 1112B is longer than the distance W in the X direction between the two first side walls 1111A. Fig. 14 is a diagram showing the state of the refrigerant as viewed from the X direction in Fig. 13. Fig. 15 is a diagram showing the state of the refrigerant as viewed from the Y direction in the distribution header 1100 according to the second embodiment, in which the cross-sectional area is the same as that of the distribution header 1100 in Fig. 13, but the distance H is shorter than the distance W. Fig. 16 is a diagram showing the state of the refrigerant as viewed from the X direction in Fig. 15.

[0056] When the distance H is shorter than the distance W, as shown in FIG. 15, the distance between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the orifice 1121 of the inner tube 1120C becomes closer. Therefore, the refrigerant jetting from the orifice 1121 is greatly affected. For example, as shown in FIG. 16, a large amount of liquid refrigerant passes through the heat transfer tube 1300 close to the refrigerant inlet / outlet tube 1120 on the refrigerant inflow side, and there are portions in the tube where the amount of liquid refrigerant is small at positions away from the refrigerant inlet / outlet tube 1120. Therefore, in the outer tube 1110C of the distribution header 1100, the change in the liquid level 2000 in the Y direction becomes large, and the amount of liquid refrigerant passing through the heat transfer tube 1300 that is not close to the refrigerant inlet / outlet tube 1120 becomes small. Therefore, the ratio of gas refrigerant to liquid refrigerant becomes biased depending on the position of the heat transfer tube 1300.

[0057] On the other hand, when the distance H is longer than the distance W, as shown in FIG. 13, the distance between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the orifice 1121 of the inner tube 1120C is greater than that in FIG. 15. Therefore, the effect of the orifice 1121 is reduced in the passage of the refrigerant through the heat transfer tube 1300. The liquid refrigerant that did not pass through the heat transfer tube 1300 close to the refrigerant inlet / outlet tube 1120 reaches a position away from the refrigerant inlet / outlet tube 1120, so that the change in the liquid level 2000 in the Y direction in the outer tube 1110C of the distribution header 1100 is reduced. Therefore, the liquid refrigerant can pass through the heat transfer tube 1300 that is not close to the refrigerant inlet / outlet tube 1120, and the ratio of gas refrigerant and liquid refrigerant passing through each heat transfer tube 1300 can be made more uniform.

[0058] As described above, according to the heat exchanger 1000 according to the second embodiment, the distribution header 1100 is a refrigerant distributor having a double-pipe structure including an outer pipe 1110C and an inner pipe 1120C. In the distribution header 1100, the outer pipe 1110C has a first member 1111 which is a top surface and two side surfaces, and a second member 1112 which is a bottom surface. The second member 1112 is covered by the first member 1111. In this case, the distribution header 1100 is shaped such that the distance H between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the bottom wall 1112B is longer than the distance W between the two first side walls 1111A. In the outer pipe 1110C, a space is provided between the heat transfer tube lower end 1310 of the heat transfer tube 1300 and the orifice 1121 of the inner pipe 1120C. This makes it possible to reduce the amount of refrigerant remaining in the heat exchanger 1000 while improving the distribution of the refrigerant flowing into each heat transfer tube 1300. Therefore, the amount of refrigerant in the entire refrigerant circuit can be reduced.

[0059] Since the second member 1112 of the outer pipe 1110C is located lower in the Z direction than the positions of the multiple orifices 1121, it is possible to reduce the amount of liquid refrigerant by maintaining the momentum of the two-phase gas-liquid refrigerant ejected from the orifices 1121. Also, since the position of the dimensional center in the Z direction of the inner pipe 1120C is lower than the position of the dimensional center in the Z direction of the outer pipe 1110C, the internal volume of the space below the outer pipe 1110C is reduced, and the amount of refrigerant remaining in the heat exchanger 1000 can be reduced.

[0060] The position of the orifice 1121 of the inner pipe 1120C in the Z direction is higher than the position of the second side wall upper end 1112D of the second side wall 1112A in the Z direction. The liquid refrigerant can be reduced by ejecting the gas-liquid two-phase refrigerant from the orifice 1121 while maintaining its momentum. In the inner pipe 1120C, the multiple orifices 1121 are installed in a direction that is downwind in the air flow. Therefore, in the heat transfer pipe 1300, the gas-liquid two-phase refrigerant with a higher ratio of liquid refrigerant flows into the flow path on the upwind side, and the gas-liquid refrigerant with a higher ratio of gas refrigerant flows into the flow path on the downwind side. This improves the heat exchange efficiency in the heat exchanger 1000.

[0061] Embodiment 3 Fig. 17 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the third embodiment as seen from the Y direction. In Fig. 17, the members and the like having the same reference numerals as those in Figs. 5 and 12 perform the same functions and operations as those described in the first and second embodiments.

[0062] As shown in FIG. 17, in the heat exchanger 1000 of the third embodiment, the second side wall upper end 1112D of the second side wall 1112A of the second member 1112 of the outer tube 1110C is chamfered. By chamfering and inclining the second side wall upper end 1112D of the second side wall 1112A, the diameter of the inner tube 1120C can be increased by the amount of the corner portion removed. Therefore, the internal volume of the space in the inner tube 1120C can be increased. When the internal volume of the space in the inner tube 1120C is increased, the internal volume of the space other than the inner tube 1120C in the space in the outer tube 1110C can be reduced. In particular, the internal volume of the lower part of the space in the outer tube 1110C can be reduced, thereby reducing the area where the liquid refrigerant is likely to stagnate.

[0063] Embodiment 4 Fig. 18 is a diagram showing a part of a cross section of the heat exchanger 1000 according to the fourth embodiment when viewed from the Y direction. In Fig. 18, the members and the like having the same reference numerals as those in Figs. 5 and 12 perform the same functions and operations as those described in the first and second embodiments.

[0064] As shown in FIG. 18, in the heat exchanger 1000 of the fourth embodiment, the inner tube 1120C has a flat upper surface and other curved surfaces, so that the inner tube 1120C has a D-shaped cross section. Since the inner tube 1120C has a D-shaped cross section, the cross-sectional area of ​​the inner tube 1120C can be increased, and the internal volume of the space within the tube can be increased. When the internal volume of the space within the inner tube 1120C is increased, the internal volume of the space within the outer tube 1110C other than the inner tube 1120C can be reduced. In particular, the internal volume of the lower part of the space within the outer tube 1110C can be reduced, so that the area where the liquid refrigerant is likely to stagnate can be reduced. [Explanation of symbols]

[0065] 100 Indoor unit, 110 Indoor heat exchanger, 120 Throttle device, 130 Indoor blower, 200 Outdoor unit, 210 Compressor, 220 Four-way valve, 230 Outdoor heat exchanger, 240 Auxiliary heat exchanger, 250 Refrigerant amount control valve, 260 Bypass piping, 270 Accumulator, 280 Outdoor blower, 300 Refrigerant piping, 400 Control device, 1000, 1000A, 1000B Heat exchanger, 1100, 1100A, 1100B Distribution header, 1110, 1110A, 1110B Header pipe, 1110C Outer pipe, 1111 First member, 1111A First side wall, 1111B Top wall, 1111C First connection portion, 1111D Lower end of first side wall, 1112 second member, 1112A second side wall, 1112B bottom wall, 1112C second connection portion, 1112D upper end of second side wall, 1113 cover, 1120, 1120A, 1120B refrigerant inlet / outlet pipes, 1120C inner pipe, 1121 orifice, 1200 folded header, 1300 heat transfer tube, 1310 lower end of heat transfer tube, 1400 corrugated fin, 2000 liquid level.

Claims

1. A plurality of heat transfer tubes arranged side by side and spaced apart along a horizontal direction and having flow paths through which a refrigerant flows in a vertical direction; a header having a cylindrical header tube extending along a direction in which the plurality of heat transfer tubes are arranged, The header pipe is a first member including a top wall into which lower ends of the heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other; a second member that includes a bottom wall and two second side walls that extend upward from both ends of the bottom wall and face each other, and that is located at a lower part of the header pipe; a distance between two of the second side walls is narrower than a distance between two of the first side walls, a height of the first side wall is higher than a height of the second side wall, a height of the second side wall is lower than a height of the first side wall, and the first side wall covers the second side wall to form the cylindrical shape, A distance from a lower end of the heat transfer tube to the bottom wall in the header pipe is longer than a distance between two of the first side walls, A heat exchanger, wherein the bottom wall of the second member has an arc-shaped curved surface when viewed from a direction in which the heat transfer tubes are arranged, and the first member covers up to a portion of the bottom wall so that a portion of the curved surface is exposed.

2. A plurality of heat transfer tubes arranged side by side and spaced apart along a horizontal direction and having flow paths through which a refrigerant flows in a vertical direction; a header having a cylindrical header tube extending along a direction in which the plurality of heat transfer tubes are arranged, The header pipe is a first member including a top wall into which lower ends of the heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other; a second member having a bottom wall and two second side walls extending upwardly from both ends of the bottom wall and facing each other; A distance between two of the second side walls is narrower than a distance between two of the first side walls, a height of the first side wall is higher than a height of the second side wall, and the first side wall covers a part of the second side wall to form the cylindrical shape, A distance from a lower end of the heat transfer tube to the bottom wall in the header pipe is longer than a distance between two of the first side walls, A heat exchanger in which a second connection portion which is a connection portion between the bottom wall of the second member and each of the two second side walls, and a first connection portion which is a connection portion between the top wall of the first member and each of the two first side walls, have inner surfaces formed with a curved surface, and a bending radius R2 of the second connection portion and a bending radius R1 of the first connection portion satisfy the relationship R2 < R1.

3. A heat exchanger as described in claim 1 or claim 2, wherein the two first side walls of the first member have lower ends bent in a direction narrowing the distance between the walls, and the lower ends of the first side walls cover a portion of the outer surface of the bottom wall of the second member.

4. A plurality of heat transfer tubes arranged side by side and spaced apart along a horizontal direction and having flow paths through which a refrigerant flows in a vertical direction; a header including an outer tube extending along a direction in which the heat transfer tubes are arranged and an inner tube disposed within the outer tube, the outer tube has a first member having a top wall into which lower ends of the heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other, and a second member having a bottom wall and two second side walls extending upward from both ends of the bottom wall and facing each other, the height of the second side wall of the second member located at a lower part of the outer tube is lower than the height of the first side wall, and the first side wall covers the second side wall to form a vertically elongated cylindrical shape, the inner tube has a plurality of orifices through which the refrigerant communicates with the outer tube, A heat exchanger, wherein the bottom wall of the second member has an arc-shaped curved surface when viewed from a direction in which the heat transfer tubes are arranged, and the first member covers up to a portion of the bottom wall so that a portion of the curved surface is exposed.

5. A plurality of heat transfer tubes arranged side by side and spaced apart along a horizontal direction and having flow paths through which a refrigerant flows in a vertical direction; a header including an outer tube extending along a direction in which the heat transfer tubes are arranged and an inner tube disposed within the outer tube, the outer tube has a first member having a top wall into which lower ends of the heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other, and a second member having a bottom wall and two second side walls extending upward from both ends of the bottom wall and facing each other, the first side walls covering a portion of the second side walls to form a cylindrical shape, the inner tube has a plurality of orifices through which the refrigerant communicates with the outer tube, A heat exchanger in which a second connection portion which is a connection portion between the bottom wall of the second member and each of the two second side walls, and a first connection portion which is a connection portion between the top wall of the first member and each of the two first side walls, have inner surfaces formed with a curved surface, and a bending radius R2 of the second connection portion and a bending radius R1 of the first connection portion satisfy the relationship R2 < R1.

6. A plurality of heat transfer tubes arranged side by side and spaced apart along a horizontal direction and having flow paths through which a refrigerant flows in a vertical direction; a header including an outer tube extending along a direction in which the heat transfer tubes are arranged and an inner tube disposed within the outer tube, the outer tube has a first member having a top wall into which lower ends of the heat transfer tubes are inserted and two first side walls extending downward from both ends of the top wall and facing each other, and a second member having a bottom wall and two second side walls extending upward from both ends of the bottom wall and facing each other, the first side walls covering a portion of the second side walls to form a cylindrical shape, the inner tube has a plurality of orifices through which the refrigerant communicates with the outer tube, A heat exchanger in which a height position of the orifice of the inner tube is higher than a height position of an upper end of the second member.

7. A heat exchanger as described in any one of claims 1, 2, and 4 to 6, wherein the top wall of the first member is a wall having a curved surface that protrudes upward in the height direction, the bottom wall of the second member is a wall having a curved surface that protrudes downward in the height direction, and the radius of the arc of the bottom wall is larger than the radius of the arc of the top wall.

8. A heat exchanger according to any one of claims 1, 2, and 4 to 6, wherein the ratio of the distance between the top wall and the bottom wall to the distance between the first side walls on the outer surface of the header is greater than 1 and less than or equal to 2.

4.

9. The heat exchanger according to any one of claims 4 to 6, wherein the position of the dimensional center in the height direction of the inner tube is lower than the position of the dimensional center in the height direction of the outer tube.

10. The heat exchanger according to any one of claims 4 to 6, wherein the inner tube has the plurality of orifices at a position that is downwind in the flow of air passing through the heat transfer tube and that is below the dimensional center in the height direction of the inner tube.

11. The heat exchanger according to any one of claims 4 to 6, wherein the second member has a shape in which parts of upper ends of the two second side walls are chamfered.

12. 7. The heat exchanger according to claim 4, wherein the inner tube is a tube having a flat upper surface and curved other surfaces, and having a D-shaped cross section.

13. An outdoor unit comprising the heat exchanger according to any one of claims 1 to 6 as an outdoor heat exchanger.

14. The outdoor unit according to claim 13; An indoor unit that has an indoor heat exchanger and a throttling device and conditions the air in the space to be air-conditioned; An air conditioning device comprising:

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