Heat exchanger

Abstract

This heat exchanger according to an embodiment of the present invention has a heat exchange tube and a header. The heat exchange tube includes therein a flow path for a heat medium. A flat plate part and a folded-back part are alternately formed along the flow path. A plurality of flat plate parts are arranged side-by-side in a first direction. The header is formed by layering a plurality of plates, and includes therein a circulation space for the heat medium. The flow path extends in a second direction intersecting the first direction in the flat plate parts. An end of the heat exchange tube at which the flow path opens is disposed on a first side in the second direction of the heat exchange tube. The header is disposed on the first side in the second direction of the heat exchange tube. The end of the heat exchange tube is connected to the header, and the flow path opens into the circulation space.

Description

heat exchanger

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a heat exchanger.

[0002] Heat exchangers are required to be cost-effective.

[0003] Japanese Patent Application Laid-Open No. 2020-51681

[0004] An object of the present invention is to provide a heat exchanger that can reduce costs.

[0005] A heat exchanger according to a first aspect of the embodiment has heat exchange tubes and a header. The heat exchange tubes have a flow path for a heat medium therein. Flat plate portions and folded portions are alternately formed along the flow path. A plurality of flat plate portions are aligned in a first direction. The header is formed by stacking a plurality of plates and has a heat medium circulation space therein. The flow path extends in a second direction intersecting the first direction in the flat plate portions. An end of the heat exchange tube where the flow path opens is arranged on a first side of the heat exchange tube in the second direction. The header is arranged on the first side of the heat exchange tube in the second direction. An end of the heat exchange tube is connected to the header, and the flow path opens into the circulation space.

[0006] In a heat exchanger according to a second aspect of the embodiment, the headers of the heat exchanger according to the first aspect include a first end header, a second end header, and an intermediate header. Only the first end in the first direction of the heat exchange tubes arranged at the ends on the first side in the first direction are connected to the first end header. Only the second end in the first direction of the heat exchange tubes arranged at the ends on the second side in the first direction are connected to the second end header. Only the pair of ends of a pair of heat exchange tubes adjacent in the first direction are connected to the intermediate header.

[0007] A heat exchanger according to a third aspect of the embodiment is the heat exchanger according to the second aspect, further comprising a connecting member. The connecting member connects the first end header, the intermediate header, and the second end header.

[0008] In a fourth embodiment of the heat exchanger, in the heat exchanger according to any one of the first to third embodiments, the header has a flow space in which a pair of ends of a pair of heat exchange tubes adjacent in the Z direction open, and a pipe member connecting the flow space to the outside is connected to a first side of the header in the second direction. The dimension of the flow space in the second direction is 4 mm or less.

[0009] In a heat exchanger according to a fifth aspect of the embodiment, in the heat exchanger according to any one of the first to third aspects, the header has a pair of flow spaces in which the flow paths of a pair of ends of a pair of heat exchange tubes adjacent in the Z direction are open. Three-way pipe members connecting the pair of flow spaces to the outside are connected to the header.

[0010] In a sixth aspect of the embodiment, the flat plate portion intersects with the first direction at an angle other than perpendicular to the first direction in the heat exchanger according to any one of the first to fifth aspects.

[0011] In a seventh embodiment of the heat exchanger according to any one of the first to sixth embodiments, when a direction perpendicular to the second direction and parallel to the flat plate portion is defined as a third direction, a plurality of flow paths are formed inside the flat plate portion in the third direction, and the cross-sectional areas of the plurality of flow paths increase from one side to the other side in the third direction.

[0012] In a heat exchanger according to an eighth aspect of the embodiment, in the heat exchanger according to any one of the first to third aspects, the cross-sectional area of ​​the flow path of the heat exchange tube arranged on the first side in the first direction, among a pair of heat exchange tubes adjacent to each other in the first direction, is larger than the cross-sectional area of ​​the flow path of the heat exchange tube arranged on the second side in the first direction. A heat exchanger according to a ninth aspect of the embodiment includes heat exchange tubes, a plate-type header, and a cylindrical header. The heat exchange tubes have a flow path for a heat medium therein. Flat portions and folded portions are alternately formed along the flow path. A plurality of flat portions are arranged in the first direction. The plate-type header is formed by stacking a plurality of plates and has a flow space for the heat medium therein. The flow path extends in the flat portions in a second direction intersecting the first direction. The end of the heat exchange tube where the flow path opens is arranged on the first side in the second direction of the heat exchange tube. The plate-type header is arranged on the first side in the second direction of the heat exchange tube. The cylindrical header is arranged outward in the second direction from the plate-type header. The end of the heat exchange tube connected to the cylindrical header is longer in the second direction than the end of the heat exchange tube connected to the plate header.

[0013] 14. Circuit diagram of a refrigeration cycle device. A perspective view of a heat exchanger in a first embodiment. A side sectional view of a main heat exchanger. An explanatory diagram of heat exchange tubes and fins. A perspective view of a heat exchanger in a second embodiment. A perspective view of an intermediate header. A side sectional view of the intermediate header. An exploded perspective view of an intermediate header in a first modified example of the second embodiment. A side sectional view of an intermediate header in a second modified example of the second embodiment. A perspective view of the periphery of an intermediate header in a third modified example of the second embodiment. A perspective view of the periphery of a header in a fourth modified example of the second embodiment. A sectional view of a heat exchange tube in a third embodiment. A sectional view of a heat exchange tube in a fourth embodiment. A side sectional view of a main heat exchanger in a fifth embodiment. A sectional view of a heat exchange tube taken along line P-P in FIG. 14.

[0014] Hereinafter, a heat exchanger and a refrigeration cycle apparatus according to an embodiment will be described with reference to the drawings. FIG. 1 is a circuit diagram of the refrigeration cycle apparatus. The refrigeration cycle apparatus 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4A, an expansion device (expansion valve) 5, and an indoor heat exchanger 4B. The components of the refrigeration cycle apparatus 1 are connected in sequence by refrigerant piping 7. In FIG. 1, the flow direction of the refrigerant (heat medium) during cooling operation is indicated by solid arrows, and the flow direction of the refrigerant during heating operation is indicated by dashed arrows. The refrigerant may be R410A, R32, R1123, R454B, R466A, carbon dioxide (CO ２ ) etc.

[0015] The compressor 2 includes a compressor main body 2A and an accumulator 2B. The compressor main body 2A compresses the low-pressure gas refrigerant taken in to produce high-temperature, high-pressure gas refrigerant. The accumulator 2B separates the gas-liquid two-phase refrigerant and supplies the gas refrigerant to the compressor main body 2A.

[0016] The four-way valve 3 reverses the flow direction of the refrigerant to switch between cooling operation and heating operation. During cooling operation, the refrigerant flows through the compressor 2, four-way valve 3, outdoor heat exchanger 4A, expansion device 5, and indoor heat exchanger 4B in this order. At this time, the refrigeration cycle apparatus 1 causes the outdoor heat exchanger 4A to function as a condenser and the indoor heat exchanger 4B to function as an evaporator to cool the room. During heating operation, the refrigerant flows through the compressor 2, four-way valve 3, indoor heat exchanger 4B, expansion device 5, and outdoor heat exchanger 4A in this order. At this time, the refrigeration cycle apparatus 1 causes the indoor heat exchanger 4B to function as a condenser and the outdoor heat exchanger 4A to function as an evaporator to heat the room.

[0017] The condenser condenses the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 by releasing heat to the outside air, turning it into a high-pressure liquid refrigerant. The expansion device 5 reduces the pressure of the high-pressure liquid refrigerant sent from the condenser, turning it into a low-temperature, low-pressure two-phase gas-liquid refrigerant. The evaporator vaporizes the low-temperature, low-pressure two-phase gas-liquid refrigerant sent from the expansion device 5 by absorbing heat from the outside air, turning it into a low-pressure gas refrigerant.

[0018] As described above, in the refrigeration cycle apparatus 1, the refrigerant, which is a working fluid, circulates while undergoing phase changes between gas and liquid refrigerants. The refrigerant releases heat during the phase change from gas to liquid, and absorbs heat during the phase change from liquid to gas. The refrigeration cycle apparatus 1 performs heating, cooling, defrosting, and the like by utilizing the heat release or absorption of the refrigerant. The heat exchanger 4 of the embodiment is used as one or both of the outdoor heat exchanger 4A and the indoor heat exchanger 4B of the refrigeration cycle apparatus 1.

[0019] (First embodiment) Fig. 2 is a perspective view of the heat exchanger 4 in the first embodiment. Fig. 3 is a side cross-sectional view of the main heat exchanger 4M. Fig. 4 is an explanatory diagram of the heat exchanger tubes 10 and the fins 40, and is a cross-sectional view taken along line IV-IV in Fig. 3.

[0020] As shown in Fig. 2, the heat exchanger 4 includes a main heat exchanger 4M and an auxiliary heat exchanger 4S. When the heat exchanger 4 functions as a condenser, the gas refrigerant condenses in the main heat exchanger 4M. The condensed liquid refrigerant is subcooled in the auxiliary heat exchanger 4S. The main heat exchanger 4M includes heat exchange tubes 10, fins 40 (see Fig. 3), a header 20, and a piping unit 30.

[0021] In the present application, the Z direction, X direction, and Y direction of the Cartesian coordinate system are defined as follows. As shown in FIG. 2 , the Z direction is the height direction of the header 20 and the stacking direction of the multiple heat exchanger tubes 10. For example, the Z direction is the vertical direction, and the +Z direction is the upward direction. The X direction is the thickness direction of the header 20. The Y direction is the width direction of the header 20. For example, the X direction and the Y direction are horizontal directions.

[0022] The main heat exchanger 4M and the auxiliary heat exchanger 4S are arranged side by side in the Z direction. The main heat exchanger 4M is arranged in the +Z direction, and the auxiliary heat exchanger 4S is arranged in the -Z direction. The heat exchanger 4 is formed in an L-shape when viewed from the Z direction, but may also be formed in a straight line. The main part of the heat exchanger 4 is the part parallel to the XZ plane. The following mainly describes this main part. A header 20 is arranged at the end of the main heat exchanger 4M in the +X direction.

[0023] The heat exchange tube 10 is made of a material with high thermal conductivity and low specific gravity, such as aluminum or an aluminum alloy. The heat exchange tube 10 is a serpentine tube. As shown in FIG. 4 , refrigerant flow paths 14 are formed inside the heat exchange tube 10. A plurality of flow paths 14 are formed side by side in the Y direction. As shown in FIG. 3 , the heat exchange tube 10 has flat portions 11 and folded portions 12. The flat portions 11 and folded portions 12 are formed alternately along the flow paths 14. In the flat portion 11, the flow paths 14 extend in the X direction (second direction). The flow paths 14 open at both end portions 15 of the heat exchange tube 10.

[0024] The flat plate portions 11 are parallel to the XY plane. A plurality of flat plate portions 11 are arranged side by side in the Z direction (first direction) and parallel to one another. One heat exchanger tube 10 has an even number of flat plate portions 11 (four in the example of FIG. 3 ). As a result, both end portions 15 of the heat exchanger tube 10 are arranged in the +X direction (first side in the second direction). Except for both end portions 15 where the flow paths 14 open, the end portions of adjacent flat plate portions 11 in the Z direction are connected by folded portions 12. A plurality of heat exchanger tubes 10 are arranged side by side in the Z direction.

[0025] The fin 40 shown in FIG. 4 is made of a material with high thermal conductivity and low specific gravity, such as aluminum or an aluminum alloy. The fin 40 is a rectangular flat plate with its longitudinal direction in the Z direction and its transverse direction in the Y direction. The fin 40 has a notch 41. The notch 41 extends from the -Y direction end of the fin 40 to the +Y direction. The -Y direction end of the notch 41 is open, and the +Y direction end is closed. Multiple notches 41 are formed side by side in the Z direction. The flat plate portion 11 of the heat exchanger tube 10 is placed inside the notch 41. The flat plate portion 11 is inserted in the +Y direction from the -Y direction opening of the notch 41. The +Y side of the fin 40 is connected, and a connecting portion 42 is included within the fin 40. The connecting portion 42 extends over the entire length of the fin 40 in the Z direction. As shown in FIG. 3 , a plurality of fins 40 are arranged side by side in the extension direction of the heat exchanger tube 10 .

[0026] As shown in Figure 3, the header 20 is disposed at the end of the main heat exchanger 4M in the +X direction. The header 20 is flat and has a thickness in the X direction. The header 20 is a plate-type header formed by stacking multiple plates. The multiple plates include an inner end plate 21, an outer end plate 22, and an intermediate plate 23. The inner end plate 21 is disposed in the -X direction, and the outer end plate 22 is disposed in the +X direction. The intermediate plate 23 is disposed between the inner end plate 21 and the outer end plate 22.

[0027] A refrigerant flow space 24 is formed inside the header 20. The flow space 24 is formed by closing the through hole of the intermediate plate 23 with the inner end plate 21 and the outer end plate 22. A plurality of flow spaces 24 are formed inside one header 20. The plurality of flow spaces 24 are arranged side by side in the Z direction.

[0028] The ends 15 of the heat exchange tubes 10 are connected to the header 20. Specifically, the ends 15 of the heat exchange tubes 10 are inserted into the through holes of the inner end plate 21 of the header 20 from the −X direction to the +X direction. The end portions 15 of the heat exchange tubes 10 are positioned in the +X direction further than the folded portions 12 that are positioned between the end portions 15. This allows the end portions 15 to be connected to the header 20 while avoiding interference between the folded portions 12 and the header 20.

[0029] The flow paths 14 of the heat exchange tubes 10 open into the flow spaces 24 of the header 20. The adjacent ends 15 of adjacent heat exchange tubes 10 in the Z direction open into the same flow space 24. For example, adjacent heat exchange tubes 10 in the Z direction are the first heat exchange tube 10a in the +Z direction and the second heat exchange tube 10b in the −Z direction. The adjacent ends 15 in the Z direction are the −Z direction end 15 of the first heat exchange tube 10a and the +Z direction end 15 of the second heat exchange tube 10b. These ends 15 open into the same first flow space 24a. Similarly, the −Z direction end 15 of the second heat exchange tube 10b and the +Z direction end 15 of the third heat exchange tube 10c open into the same second flow space 24b. The first flow spaces 24a and the second flow spaces 24b are alternately arranged along the Z direction.

[0030] As shown in Fig. 2, the piping unit 30 is disposed in the +X direction of the header 20. As shown in Fig. 3, the piping unit 30 has a pipe member 34 connected to the header 20 in the +X direction. The pipe member 34 is inserted into the through-hole in the outer end plate 22 of the header 20 from the +X direction to the -X direction. The flow path of the pipe member 34 opens into the flow space 24 of the header 20. The first pipe member 34a opens into the first flow space 24a described above, and the second pipe member 34b opens into the second flow space 24b.

[0031] As shown in Fig. 2, the first pipe members 34a and the second pipe members 34b are arranged alternately along the Z direction. The piping unit 30 has a distributor 32. When the main heat exchanger 4M functions as an evaporator, the distributor 32 distributes the gas-liquid two-phase refrigerant approximately evenly to the multiple second pipe members 34b. The assembly of the heat exchanger tubes 10, the header 20, and the piping unit 30 is brazed, thereby sealing the connections between the components.

[0032] The flow of refrigerant when the heat exchanger 4 functions as an evaporator will be described. The refrigerant flowing out of the expansion device 5 (see FIG. 1) flows into the auxiliary heat exchanger 4S. The refrigerant flowing out of the auxiliary heat exchanger 4S is distributed by the distributor 32 and flows into the multiple second pipe members 34b of the main heat exchanger 4M. As shown in FIG. 3, the refrigerant flows from the second pipe members 34b into the second flow space 24b of the header 20. For example, the refrigerant is divided into the second heat exchange tube 10b and the third heat exchange tube 10c in the second flow space 24b. As the refrigerant flows through the heat exchange tubes 10, it exchanges heat with the outside air passing through the main heat exchanger 4M.

[0033] The refrigerant that has passed through the heat exchange tubes 10 flows into the first flow space 24a of the header 20. For example, the refrigerant that has passed through the second heat exchange tube 10b and the first heat exchange tube 10a joins in the first flow space 24a of the header 20. The refrigerant flows from the first flow space 24a to the first pipe member 34a. As shown in FIG. 2, the refrigerant from the multiple first pipe members 34a joins and is supplied to the compressor 2 (see FIG. 1). When the heat exchanger 4 functions as a condenser, the refrigerant flows in the opposite direction to when it functions as an evaporator.

[0034] As described above, in the main heat exchanger 4M of the first embodiment, the heat exchange tubes 10 are connected in parallel in the refrigerant flow direction. In this case, the refrigerant flows in parallel through the heat exchange tubes 10. Alternatively, the heat exchange tubes 10 may be connected in series in the refrigerant flow direction. In this case, the refrigerant flows sequentially through the heat exchange tubes 10. In this case, the flow space 24 of the header 20 shown in FIG. 3 is used to turn back the refrigerant between the heat exchange tubes 10 adjacent in the Z direction.

[0035] As described above in detail, the heat exchanger 4 of the first embodiment includes heat exchange tubes 10 and a header 20. The heat exchange tubes 10 have heat medium flow paths 14 therein. Flat plate portions 11 and folded portions 12 are alternately formed along the flow paths 14. The flat plate portions 11 are aligned in the Z direction. The header 20 is formed by stacking multiple plates and has a heat medium flow space 24 therein. The flow paths 14 extend in the X direction, which intersects with the Z direction, in the flat plate portions 11. The end portions 15 of the heat exchange tubes 10, where the flow paths 14 open, are positioned in the +X direction of the heat exchange tubes 10. The header 20 is positioned in the +X direction of the heat exchange tubes 10. The end portions 15 of the heat exchange tubes 10 are connected to the header 20, and the flow paths 14 open to the flow space 24.

[0036] The heat exchanger tubes 10 are serpentine tubes. The ends 15 of the heat exchanger tubes 10 are arranged in the +X direction. Therefore, the headers 20 are arranged only in the +X direction of the heat exchanger tubes 10, and no headers are required in the opposite direction. In addition, the headers 20 are formed by stacking multiple plates. These features allow the cost of the heat exchanger 4 to be reduced.

[0037] Second Embodiment Fig. 5 is a perspective view of a heat exchanger 4 according to a second embodiment. The heat exchanger 4 according to the second embodiment differs from the first embodiment in that it includes a first end header 20e1, a second end header 20e2, and an intermediate header 20m. Descriptions of the second embodiment that are similar to the first embodiment may be omitted.

[0038] The main heat exchanger 4M has headers 20 including a first end header 20e1, a second end header 20e2, and an intermediate header 20m. The first end header 20e1 is disposed at the end of the main heat exchanger 4M on the +Z direction side (first side in the first direction). Only the +Z direction ends 15 (see FIG. 3) of the heat exchange tubes 10 disposed at the +Z direction end of the main heat exchanger 4M are connected to the first end header 20e1. The second end header 20e2 is disposed at the end of the main heat exchanger 4M on the −Z direction side (second side in the first direction). Only the −Z direction ends 15 of the heat exchange tubes 10 disposed at the −Z direction end of the main heat exchanger 4M are connected to the second end header 20e2.

[0039] The intermediate header 20m is disposed in the middle of the main heat exchanger 4M in the Z direction. The intermediate header 20m is disposed between the first end header 20e1 and the second end header 20e2. A plurality of intermediate headers 20m are disposed side by side in the Z direction.

[0040] FIG. 6 is a perspective view of the intermediate header 20m. FIG. 7 is a side cross-sectional view of the intermediate header 20m. Only a pair of end portions 15 of a pair of heat exchange tubes 10 adjacent in the Z direction are connected to the intermediate header 20m. Only one flow space 24 is formed inside the intermediate header 20m, to which the flow paths 14 of the pair of heat exchange tubes 10 open. As shown in FIG. 5, the intermediate header 20m has a first intermediate header 20a and a second intermediate header 20b. Only the first flow space 24a shown in FIG. 3 is formed inside the first intermediate header 20a. Only the second flow space 24b is formed inside the second intermediate header 20b. The first intermediate header 20a and the second intermediate header 20b are formed small and alternately arranged at intervals in the Z direction.

[0041] As described above, the heat exchanger 4 of the second embodiment has a first end header 20e1, a second end header 20e2, and an intermediate header 20m. Only the +Z-direction end 15 of the heat exchange tube 10 arranged at the end in the +Z direction is connected to the first end header 20e1. Only the −Z-direction end 15 of the heat exchange tube 10 arranged at the end in the −Z direction is connected to the second end header 20e2. Only a pair of adjacent end portions 15 of a pair of heat exchange tubes 10 adjacent in the Z direction is connected to the intermediate header 20m.

[0042] The first end header 20e1, the intermediate header 20m, and the second end header 20e2 are formed small and are arranged at intervals in the Z direction, which reduces the material cost of the headers 20 and therefore the cost of the heat exchanger 4.

[0043] The heat exchanger 4 may have a connecting member 29 shown in FIG. 6 . The connecting member 29 connects the first end header 20e1, the intermediate header 20m, and the second end header 20e2. The connecting member 29 is formed, for example, to connect the +Y direction ends of the first end header 20e1, the intermediate header 20m, and the second end header 20e2. The connecting member 29 may be formed integrally with the headers 20.

[0044] As described above, the first end header 20e1, the intermediate header 20m, and the second end header 20e2 are spaced apart in the Z direction. By providing the connecting member 29 that connects these headers, they can be easily handled in the manufacturing process of the heat exchanger 4. This allows the manufacturing cost of the heat exchanger 4 to be reduced.

[0045] As shown in Figure 7, the intermediate header 20m has one flow space 24 into which the flow paths 14 of a pair of end portions 15 of a pair of heat exchange tubes 10 adjacent in the Z direction open. A pipe member 34 is connected to the intermediate header 20m in the +Z direction. The pipe member 34 connects the flow space 24 to the outside. The pipe member 34 is connected to approximately the center of the intermediate header 20m in the Y direction. The pipe member 34 is connected, for example, between the pair of heat exchange tubes 10 (at the center) in the Z direction. The pipe member 34 opens into the flow space 24. The opening of the pipe member 34 faces the inner end plate 21 of the intermediate header 20m.

[0046] The refrigerant that flows from the outside into the flow space 24 through the pipe member 34 is distributed to the pair of heat exchange tubes 10 in the flow space 24. When the refrigerant is in a gas-liquid two-phase state, it may not be distributed evenly due to the influence of gravity, etc. If the liquid refrigerant is concentrated in one of the heat exchange tubes 10, the heat exchange efficiency decreases.

[0047] The X-direction dimension DX of the flow space 24 is preferably 4 mm or less. This positions the opening of the pipe member 34 and the inner end plate 21 of the intermediate header 20 m close to each other. The refrigerant that flows into the flow space 24 from the opening of the pipe member 34 violently collides with the inner end plate 21 and is dispersed radially. The effect of gravity on the gas-liquid two-phase refrigerant is suppressed. This allows the refrigerant to be distributed approximately evenly to the pair of heat exchanger tubes 10, improving heat exchange efficiency. Furthermore, three-way pipe members for distributing the refrigerant are not required, thereby reducing the cost and space required for the heat exchanger 4.

[0048] 8 is an exploded perspective view of the intermediate header 20m according to a first modification of the second embodiment. In the first modification, the internal structure of the intermediate header 20m differs from that of the second embodiment. The description of the first modification that is similar to the second embodiment may be omitted.

[0049] The intermediate header 20m has a first intermediate plate 23f, a second intermediate plate 23g, and a third intermediate plate 23h as intermediate plates. The first intermediate plate 23f is disposed in the −X direction, the third intermediate plate 23h is disposed in the +X direction, and the second intermediate plate 23g is disposed between the first intermediate plate 23f and the third intermediate plate 23h, i.e., in the center in the X direction.

[0050] A first space 25a and a second space 25b are formed in the first intermediate plate 23f. The first space 25a and the second space 25b penetrate the first intermediate plate 23f in the X direction. The flow path 14 of the first heat exchange tube 10a opens into the first space 25a. The flow path 14 of the second heat exchange tube 10b opens into the second space 25b.

[0051] Four through holes penetrating in the X direction are formed in the second intermediate plate 23g. The four through holes are a first through hole 51, a second through hole 52, a third through hole 53, and a fourth through hole 54. The first through hole 51 and the fourth through hole 54 open to the first space 25a in the -X direction. The second through hole 52 and the third through hole 53 open to the second space 25b in the -X direction.

[0052] A spiral space 26 is formed in the third intermediate plate 23h. The spiral space 26 penetrates the third intermediate plate 23h in the X direction. The spiral space 26 is formed in a spiral shape when viewed from the X direction. The spiral space 26 extends from approximately the center of the first intermediate plate 23f in the Y and Z directions in the +Z direction, +Y direction, −Z direction, −Y direction, and +Z direction in this order.

[0053] The +X direction side of first through hole 51 opens at the +Y direction and +Z direction corners of spiral space 26. The +X direction side of second through hole 52 opens at the +Y direction and -Z direction corners of spiral space 26. The +X direction side of third through hole 53 opens at the -Y direction and -Z direction corners of spiral space 26. The +X direction side of fourth through hole 54 opens at the -Y direction and +Z direction corners of spiral space 26.

[0054] The refrigerant flows from pipe member 34 into approximately the center of vortex space 26 in the Y and Z directions. The refrigerant flows through vortex space 26 in the +Z and +Y directions. A portion of the refrigerant flows into first through hole 51. The refrigerant flows through vortex space 26 in the -Z direction. A portion of the refrigerant flows into second through hole 52. The refrigerant flows through vortex space 26 in the -Y direction. A portion of the refrigerant flows into third through hole 53. The refrigerant flows through vortex space 26 in the +Z direction. The remainder of the refrigerant flows into fourth through hole 54.

[0055] The amount of refrigerant flowing from the spiral space 26 into the four through holes is greatest through the first through hole 51 and least through the fourth through hole. The refrigerant that flows into the first through hole 51 and the fourth through hole 54 flows into the first heat exchange tube 10a via the first space 25a. The refrigerant that flows into the second through hole 52 and the third through hole 53 flows into the second heat exchange tube 10b via the second space 25b. This allows the refrigerant to be distributed approximately evenly to the pair of heat exchange tubes 10, improving heat exchange efficiency.

[0056] 9 is a side cross-sectional view of an intermediate header 20m in a second modified example of the second embodiment. The second modified example of the second embodiment will be described. The intermediate header 20m in the second modified example differs from the second embodiment in that it has a protrusion 27 on the inner end plate 21. The description of the second modified example in respect of the same points as the second embodiment may be omitted.

[0057] The intermediate header 20m has a protrusion 27 on the inner end plate 21. The protrusion 27 protrudes in the +X direction toward the inside of the flow space 24. The protrusion 27 tapers toward the +X direction. The protrusion 27 is disposed in a position facing the opening of the pipe member 34.

[0058] The refrigerant that flows into the flow space 24 from the opening of the pipe member 34 collides with the protrusions 27 and is diffused radially. This reduces the effect of gravity on the gas-liquid two-phase refrigerant. This allows the refrigerant to be distributed approximately evenly to the pair of heat exchange tubes 10, improving heat exchange efficiency.

[0059] The intermediate header 20m may have a recess in the inner end plate 21 instead of the protrusion 27. The recess is recessed in the -X direction toward the outside of the flow space 24. The recess tapers in the -X direction. The refrigerant that flows into the flow space 24 from the opening of the pipe member 34 collides with the recess and is diffused radially. This allows the refrigerant to be distributed approximately evenly to the pair of heat exchange tubes 10, improving heat exchange efficiency.

[0060] The intermediate header 20m may have a throttle in the flow space 24. The refrigerant flowing in from the pipe member 34 passes through the throttle and is sprayed radially. This allows the refrigerant to be distributed approximately evenly to the pair of heat exchange tubes 10, improving heat exchange efficiency.

[0061] 10 is a perspective view of the periphery of the intermediate header 20m in a third modified example of the second embodiment. The third modified example differs from the second embodiment in that a three-way pipe member (three-way bend) 35 is connected to the intermediate header 20m. A description of the third modified example that is similar to the second embodiment may be omitted.

[0062] The intermediate header 20m has a pair of flow spaces 25a, 25b into which the flow paths 14 of a pair of end portions 15 adjacent in the Z direction of a pair of heat exchange tubes 10a, 10b adjacent in the Z direction open. The pair of flow spaces 25a, 25b are a first space 25a and a second space 25b. The flow path 14 of the first heat exchange tube 10a opens into the first space 25a. The flow path 14 of the second heat exchange tube 10b opens into the second space 25b.

[0063] A three-way pipe member 35 is connected to the intermediate header 20m in the +X direction. The three-way pipe member 35 connects the pair of flow spaces 25a, 25b with the outside. The three-way pipe member 35 has a U-shaped portion 36 and a branch portion 37. Both ends of the U-shaped portion 36 open to the first space 25a and the second space 25b. The branch portion 37 branches from the U-shaped portion 36 to the outside. The refrigerant that flows into the branch portion 37 from the outside is distributed approximately evenly in the U-shaped portion 36 and flows into the first space 25a and the second space 25b.

[0064] In this way, the three-way pipe member 35, which connects the pair of flow spaces 25a, 25b with the outside, is connected to the intermediate header 20m, so that the refrigerant is distributed approximately evenly to the pair of heat exchange tubes 10, improving heat exchange efficiency.

[0065] 11 is a perspective view of the periphery of the header 20 in a fourth modified example of the second embodiment. The fourth modified example differs from the second embodiment in that the header 20 has a cylindrical header 20c in addition to the plate-type header 28. Explanation of the fourth modified example that is similar to the second embodiment may be omitted.

[0066] The plate-type headers 28 are the second intermediate header 20b and the second end header 20e2 shown in FIG. 5 . The tubular header 20c replaces the first end header 20e1 and the first intermediate header 20a shown in FIG. 5 . The tubular header 20c is formed in a cylindrical or semi-cylindrical shape. The length of the tubular header 20c in the Z direction may be the same as that of the heat exchanger 4 or slightly shorter than that of the main heat exchanger 4M. The tubular header 20c is disposed in the +X direction of the plate-type header 28, i.e., further outward in the X direction than the plate-type header 28. The ends of the heat exchange tubes 10 connected to the tubular header 20c extend longer in the +X direction than the ends of the heat exchange tubes 10 connected to the plate-type header 28. The refrigerant flowing from the multiple heat exchange tubes 10 into the tubular header 20c joins inside the tubular header 20c and flows out to the outside. The refrigerant that flows into the cylindrical header 20c from the outside is divided inside the cylindrical header 20c and flows out into the plurality of heat exchange tubes 10.

[0067] The heat exchanger tubes 10 are serpentine tubes. The ends 15 of the heat exchanger tubes 10 are arranged in the +X direction. Therefore, the plate-type headers 28 and the cylindrical headers 20c are arranged only in the +X direction of the heat exchanger tubes 10, and no headers are required in the opposite direction. This reduces the cost of the heat exchanger 4.

[0068] 12 is a cross-sectional view of a heat exchanger tube 10 according to a third embodiment. The heat exchanger tube 10 according to the third embodiment differs from the first embodiment in that the flat plate portion 11 is inclined. The description of the third embodiment in respect to the same points as those of the first embodiment may be omitted.

[0069] In this embodiment, the flat plate portions 11 of the heat exchanger tubes 10 intersect with the Z direction at an angle other than perpendicular. When the Z direction is vertical, the flat plate portions 11 are inclined with respect to the horizontal direction. When the heat exchanger 4 functions as a condenser, the refrigerant radiates heat, causing the temperature of the heat exchanger tubes 10 to drop. This causes condensation water to form on the heat exchanger tubes 10. If the condensation water accumulates on the flat plate portions 11, the heat exchange efficiency will decrease.

[0070] In contrast, in the heat exchanger tube 10 of this embodiment, the flat plate portion 11 intersects with the Z direction at an angle other than perpendicular, so that the condensed water slides down the inclined flat plate portion 11 due to gravity. This prevents the heat exchange efficiency from decreasing due to the accumulation of condensed water.

[0071] In the example of Figure 12, the flat plate portion 11 is inclined in the -Z direction toward the +Y direction. Condensed water slides down the flat plate portion 11 in the +Y direction. As described above, connecting portions 42 extending in the Z direction are formed at the ends of the fins 40 in the +Y direction. Condensed water flows down the connecting portions 42 in the -Z direction. This effectively prevents condensed water from accumulating on the flat plate portion 11.

[0072] The module including the heat exchanger 4 has a fan 8. The fan 8 passes outside air between the heat exchange tubes 10 of the heat exchanger 4. In the example of FIG. 12, the fan 8 is disposed in the -Y direction of the heat exchanger 4. That is, the -Y direction of the heat exchanger 4 is the inside of the module. As described above, condensed water slides down the flat plate portion 11 in the +Y direction. This allows the condensed water to be discharged to the outside of the module.

[0073] 13 is a cross-sectional view of a heat exchanger tube 10 according to a fourth embodiment. The heat exchanger tube 10 according to the fourth embodiment differs from the first embodiment in that the cross-sectional areas of the flow paths 14 are different from one another. The description of the fourth embodiment that is similar to the first embodiment may be omitted.

[0074] As described above, refrigerant flow paths 14 are formed inside the heat exchanger tube 10. In this embodiment, the flat plate portion 11 is parallel to the Y direction (third direction). Therefore, the multiple flow paths 14 are formed side by side in the Y direction. In the heat exchanger tube 10 of this embodiment, the cross-sectional area of ​​the multiple flow paths 14 increases from one side to the other in the Y direction. In the example of FIG. 13 , the cross-sectional area of ​​the multiple flow paths 14 increases from the +Y direction to the −Y direction. In this embodiment, the fan 8 causes outside air to pass from the −Y direction to the +Y direction. In other words, the +Y direction is downwind and the −Y direction is upwind.

[0075] As described above, in the heat exchange tube 10 of this embodiment, the cross-sectional area of ​​the multiple flow paths 14 increases from the +Y direction to the -Y direction. As a result, the more refrigerant flows through the flow paths 14 in the -Y direction, the more refrigerant flows through them. On the other hand, the heat exchange tube 10 is arranged so that outside air passes through from the -Y direction to the +Y direction. The temperature difference between the outside air and the refrigerant increases as the flow paths 14 are closer to the wind in the -Y direction, and the amount of heat exchanged between them increases. As a result, the heat exchange efficiency of the heat exchange tube 10 can be improved. Note that the heat exchange tube 10 may be arranged so that the cross-sectional area of ​​the multiple flow paths 14 increases from the -Y direction to the +Y direction, and so that outside air passes through from the +Y direction to the -Y direction.

[0076] Fifth Embodiment Fig. 14 is a side cross-sectional view of a main heat exchanger 4M in a fifth embodiment. The main heat exchanger 4M of the fifth embodiment differs from the first embodiment in that a plurality of heat exchange tubes 10 are connected in series. Fig. 15 is a cross-sectional view of the heat exchange tubes 10a, 10b taken along line P-P in Fig. 14. The fifth embodiment differs from the first embodiment in that the cross-sectional areas of the flow paths 14 of the plurality of heat exchange tubes 10 are different from one another. Description of the fifth embodiment that is similar to the first embodiment may be omitted.

[0077] As in the first embodiment, a pipe member 34 is connected to the flow space 24e1 formed at the end of the header 20 in the +Z direction. The same applies to the flow space (not shown) formed at the end of the header 20 in the −Z direction. In contrast, no pipe member is connected to the flow space 24 formed in the middle of the header 20 in the Z direction.

[0078] When the heat exchanger 4 functions as a condenser, the refrigerant flows into the main heat exchanger 4M through the flow space 24e1 formed at the end of the header 20 in the +Z direction. The refrigerant that flows through the heat exchange tube 10a turns around at the flow space 24 formed in the middle of the header 20 in the Z direction and flows into the adjacent heat exchange tube 10b in the -Z direction. After flowing through all the heat exchange tubes 10 in order, the refrigerant passes through a flow space (not shown) formed at the end of the header 20 in the -Z direction, passes through a pipe member, for example, that connects the flow space to the outside, and then flows out of the main heat exchanger 4M. The refrigerant flows from the main heat exchanger 4M into the auxiliary heat exchanger 4S (see FIG. 2). When the heat exchanger 4 functions as an evaporator, the refrigerant flow is the opposite of when it functions as a condenser. As such, in the main heat exchanger 4M of this embodiment, multiple heat exchange tubes 10 are connected in series in the refrigerant flow direction. It should be noted that not all of the multiple heat exchange tubes 10 need be connected in series. For example, a combination is possible in which the heat exchanger tubes 10 turn back once in the flow space 24 and then flow out of the next flow space 24. That is, several heat exchanger tubes 10 may be connected in series to form a series tube set, and a plurality of series tube sets may be connected in parallel.

[0079] When the heat exchanger 4 functions as a condenser, the refrigerant changes from a gas to a liquid. When the heat exchanger 4 functions as an evaporator, the refrigerant changes from a two-phase state of gas and liquid to a gas. That is, the amount of gaseous refrigerant flowing through the heat exchange tubes 10 arranged in the +Z direction increases. In the flow path through which the gaseous refrigerant flows, the larger the cross-sectional area, the smaller the pressure loss.

[0080] 15, the heat exchanger 4 of this embodiment has multiple heat exchange tubes 10a, 10b with different cross-sectional areas of the flow paths 14. In particular, the cross-sectional area of ​​the flow paths 14 of the heat exchange tube 10a arranged in the +Z direction is larger than the cross-sectional area of ​​the flow paths 14 of the heat exchange tube 10b arranged in the -Z direction. The flow rate of the gas refrigerant is increased in the heat exchange tube 10a arranged in the +Z direction. By increasing the cross-sectional area of ​​the flow paths of the heat exchange tube 10a arranged in the +Z direction, the pressure loss of the refrigerant can be suppressed.

[0081] The main heat exchanger 4M has a larger flow rate of gas refrigerant than the auxiliary heat exchanger 4S. Therefore, it is desirable that the cross-sectional area of ​​the flow passage of the heat exchange tubes 10 of the main heat exchanger 4M is larger than the cross-sectional area of ​​the flow passage of the heat exchange tubes 10 of the auxiliary heat exchanger 4S. This makes it possible to suppress pressure loss of the refrigerant.

[0082] According to at least one of the embodiments described above, the heat exchanger 4 has serpentine heat exchanger tubes 10 and plate-type headers 20. This allows the cost of the heat exchanger 4 to be reduced.

[0083] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0084] 4...heat exchanger, 10...heat exchange tube, 11...flat plate portion, 12...folded portion, 14...flow path, 15...end portion, 20...header, 21...inner end plate (plate), 22...outer end plate (plate), 23...intermediate plate (plate), 20e1...first end header, 20e2...second end header, 20m...intermediate header, 24...flow space, 25a...first space (pair of flow spaces), 25b...second space (pair of flow spaces), 29...connecting member, 34...pipe member, 35...three-way pipe member.

Claims

1. A heat exchanger comprising: a heat exchange tube having a flow path for a heat medium therein, with flat plate portions and folded portions alternately formed along the flow path, and a plurality of the flat plate portions lined up in a first direction; and a header formed by stacking a plurality of plates and having a circulation space for the heat medium therein, wherein the flow path extends in a second direction intersecting the first direction in the flat plate portions, an end of the heat exchange tube where the flow path opens is disposed on a first side of the heat exchange tube in the second direction, the header is disposed on the first side of the heat exchange tube in the second direction, the end of the heat exchange tube is connected to the header, and the flow path opens into the circulation space.

2. The heat exchanger as described in claim 1, wherein the headers include: a first end header to which only the ends on the first side in the first direction of the heat exchange tubes arranged at the ends on the first side in the first direction are connected; a second end header to which only the ends on the second side in the first direction of the heat exchange tubes arranged at the ends on the second side in the first direction are connected; and an intermediate header to which only the ends of a pair of the heat exchange tubes adjacent in the first direction are connected.

3. The heat exchanger according to claim 2, further comprising a connecting member connecting said first end header, said intermediate header and said second end header.

4. A heat exchanger as described in any one of claims 1 to 3, wherein the header has one flow space in which the flow paths of a pair of the ends of a pair of the heat exchange tubes adjacent in the first direction are open, a pipe member connecting the one flow space to the outside is connected to a first side of the header in the second direction, and the dimension of the one flow space in the second direction is 4 mm or less.

5. A heat exchanger as described in any one of claims 1 to 3, wherein the header has a pair of flow spaces in which the flow paths of a pair of the ends of a pair of the heat exchange tubes adjacent in the first direction are open, and a three-way pipe member connecting the pair of flow spaces to the outside is connected to the header.

6. A heat exchanger according to any one of claims 1 to 3, wherein the flat plate portion intersects with the first direction at an angle other than perpendicular.

7. A heat exchanger as described in any one of claims 1 to 3, wherein, when a direction perpendicular to the second direction and parallel to the flat plate portion is defined as a third direction, a plurality of the flow paths are formed inside the flat plate portion in a line in the third direction, and the cross-sectional areas of the plurality of flow paths increase from one side to the other side in the third direction.

8. A heat exchanger as described in any one of claims 1 to 3, wherein, of a pair of heat exchange tubes adjacent to each other in the first direction, the cross-sectional area of ​​the flow path of the heat exchange tube arranged on a first side in the first direction is larger than the cross-sectional area of ​​the flow path of the heat exchange tube arranged on a second side in the first direction.

9. A heat exchanger comprising: a heat exchange tube having a flow path for a heat medium therein, with flat plate portions and folded portions alternately formed along the flow path, and with a plurality of the flat plate portions lined up in a first direction; a plate-type header formed by stacking a plurality of plates and having a circulation space therein for the heat medium; and a cylindrical header, wherein the flow path extends in a second direction intersecting the first direction in the flat plate portions, an end of the heat exchange tube where the flow path opens is arranged on a first side of the heat exchange tube in the second direction, the plate-type header is arranged on the first side of the heat exchange tube in the second direction, the cylindrical header is arranged outside the plate-type header in the second direction, and the end of the heat exchange tube connected to the cylindrical header is longer in the second direction than the end of the heat exchange tube connected to the plate-type header.

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