Heat exchanger and refrigeration cycle device

Abstract

This heat exchanger comprises a plurality of heat transfer pipes and a refrigerant header to which refrigerant piping and the plurality of heat transfer pipes are connected and which can distribute a refrigerant flowing in from the refrigerant piping to the plurality of heat transfer pipes. The refrigerant header includes: a tubular main header part extending vertically; a first orifice plate located in the interior of the main header part and having a first orifice hole formed therein; and a second orifice plate located in the interior of the main header part and having a second orifice hole formed therein. The interior space of the main header part is partitioned by the first orifice plate and the second orifice plate into a first space, a second space, and a third space. The first space and the second space are joined to each other through the first orifice hole, the second space and the third space are joined to each other through the second orifice hole, the second space is located vertically above the first space, the third space is located vertically above the second space, the refrigerant piping is connected to the first space, and mutually different heat transfer pipes among the plurality of heat transfer pipes are connected to the second space and the third space, respectively.

Description

Heat exchanger and refrigeration cycle device

[0001] The present disclosure relates to a heat exchanger and a refrigeration cycle device.

[0002] Refrigeration cycle devices, such as air conditioners, that utilize the condensation and evaporation of a refrigerant are known. In such refrigeration cycle devices, it is important to improve the energy efficiency of the heat exchanger included in the refrigeration cycle device. When the heat exchanger of a refrigeration cycle device functions as an evaporator, a two-phase refrigerant flows into multiple heat transfer tubes included in the heat exchanger. In this case, the capacity of the heat exchanger changes depending on the flow rate of the two-phase refrigerant distributed to each heat transfer tube. For example, when a vertical distributor (refrigerant header) is used to distribute a two-phase refrigerant, the liquid refrigerant and the gas refrigerant separate due to gravity, which can cause the amount of refrigerant distributed to each heat transfer tube to change depending on the flow rate of the refrigerant flowing into the distributor. To improve the energy efficiency of the heat exchanger, it is preferable that the distribution ratio of the liquid refrigerant distributed to each heat transfer tube from the vertical distributor is not likely to change even when the flow rate of the refrigerant flowing into the distributor changes.

[0003] For example, Patent Document 1 describes a header manifold (refrigerant header) that has a mixing chamber and a plurality of communicating chambers into which the refrigerant in the mixing chamber is distributed, with the aim of equalizing the wetness of the refrigerant flowing into a plurality of flat tubes (heat transfer tubes).

[0004] JP 2013-137193 A

[0005] However, the header collecting pipe described in Patent Document 1 requires vertical and horizontal partition plates to be provided inside the header collecting pipe in order to provide the mixing chamber and the multiple communication chambers. This complicates the structure of the header collecting pipe, increases the number of parts in the header collecting pipe, and reduces the assembly of the header collecting pipe. This results in problems of a deterioration in the manufacturing cost and productivity of the heat exchanger.

[0006] In view of the above circumstances, one of the objects of the present disclosure is to provide a heat exchanger that can suppress changes in the distribution ratio of refrigerant to multiple heat transfer tubes using a refrigerant header with a simple structure, and a refrigeration cycle device equipped with such a heat exchanger.

[0007] One aspect of a heat exchanger according to the present disclosure is a heat exchanger for a refrigeration cycle device, the heat exchanger including a plurality of heat transfer tubes, and a refrigerant header to which a refrigerant pipe and the plurality of heat transfer tubes are connected and which can distribute refrigerant flowing from the refrigerant pipe to the plurality of heat transfer tubes, the refrigerant header including a cylindrical header main body extending vertically, a first orifice plate located inside the header main body and having a first orifice hole formed therein, and a second orifice plate located inside the header main body and having a second orifice hole formed therein, and an internal space of the header main body is formed between the first orifice hole and the second orifice hole, The orifice plate and the second orifice plate separate the space into a first space, a second space, and a third space, the first space and the second space are connected to each other via the first orifice hole, the second space and the third space are connected to each other via the second orifice hole, the second space is located vertically above the first space, the third space is located vertically above the second space, the refrigerant piping is connected to the first space, and different heat transfer tubes from the plurality of heat transfer tubes are connected to the second space and the third space.

[0008] One aspect of a refrigeration cycle device according to the present disclosure includes the above-described heat exchanger.

[0009] According to one aspect of the present disclosure, in a heat exchanger of a refrigeration cycle device, a refrigerant header with a simple structure can suppress changes in the distribution ratio of refrigerant to a plurality of heat transfer tubes.

[0010] FIG. 1 is a schematic diagram showing a general configuration of a refrigeration cycle device in embodiment 1. FIG. 2 is a partial cross-sectional view showing a schematic configuration of a heat exchanger in embodiment 1. FIG. 3 is a cross-sectional view showing a first refrigerant header in embodiment 1. FIG. 4 is a cross-sectional view showing a first refrigerant header in embodiment 1, taken along IV-IV in FIG. 3. FIG. 5 is a diagram showing an example of a refrigerant distribution amount in a first refrigerant header of a comparative example. FIG. 6 is a diagram showing an example of a refrigerant distribution amount in a first refrigerant header of embodiment 1. FIG. 7 is a partial cross-sectional view showing a part of a heat exchanger in embodiment 2. FIG. 8 is a partial cross-sectional view showing a part of a heat exchanger in embodiment 3.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are used to denote the same or equivalent parts, and this applies throughout the specification. In addition, hatching may be omitted in cross-sectional views to improve visibility. Furthermore, the forms of components shown in the entire specification are merely examples, and the present disclosure is not limited to these descriptions. Furthermore, the shape, size, and arrangement of the configurations shown in each drawing may be modified as appropriate within the scope of the technical concept of the present disclosure.

[0012] The drawings also show the X-axis, Y-axis, and Z-axis as appropriate. The X-axis indicates one of the horizontal directions. The Y-axis indicates the other of the horizontal directions. The Z-axis indicates the vertical direction. In the following description, the horizontal direction along the X-axis is referred to as the "front-rear direction X," the horizontal direction along the Y-axis is referred to as the "left-right direction Y," and the vertical direction along the Z-axis is referred to as the "vertical direction Z." The front-rear direction X, left-right direction Y, and vertical direction Z are perpendicular to one another. The side of the vertical direction Z toward which the Z-axis arrow points (+Z side) is the upper side, and the side of the vertical direction Z opposite to the side toward which the Z-axis arrow points (-Z side) is the lower side. In the following description, the side of the front-rear direction X toward which the X-axis arrow points (+X side) is referred to as the "front side," and the side of the front-rear direction X opposite to the side toward which the X-axis arrow points (-X side) is referred to as the "rear side." The side of the left-right direction Y toward which the arrow of the Y axis points (+Y side) is defined as the "right side," and the side opposite to the side toward which the arrow of the Y axis points (-Y side) is defined as the "left side." In the following embodiments, the left-right direction Y corresponds to the "intersecting direction" that intersects with the vertical direction Z, the right side corresponds to the "first side," and the left side corresponds to the "second side" opposite to the first side.

[0013] Embodiment 1. FIG. 1 is a schematic diagram showing the overall configuration of a refrigeration cycle apparatus 100 in Embodiment 1. The refrigeration cycle apparatus 100 shown in FIG. 1 is an apparatus that performs heat pumping by utilizing condensation and evaporation of a refrigerant 19. The refrigeration cycle apparatus 100 in Embodiment 1 is an air conditioner. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes an outdoor unit 10, an indoor unit 20, and a circulation path section 18 that connects the outdoor unit 10 and the indoor unit 20. The outdoor unit 10 is disposed outdoors. The indoor unit 20 is disposed indoors. The outdoor unit 10 and the indoor unit 20 are connected to each other by the circulation path section 18 through which the refrigerant 19 circulates. The outdoor unit 10 and the indoor unit 20 are heat exchange units that exchange heat with air.

[0014] The refrigeration cycle apparatus 100 can adjust the temperature of indoor air by exchanging heat between the refrigerant 19 flowing through the circulation path 18 and the air in a room where the indoor unit 20 is located. Examples of the refrigerant 19 include fluorine-based refrigerants or hydrocarbon-based refrigerants with low global warming potential (GWP). Examples of the refrigerant 19 include a single refrigerant selected from R1234yf, R1234ze, R32, and R290, a mixture of two or more of these refrigerants, or a mixture of any of these refrigerants with another refrigerant. Examples of the refrigerant 19 include a mixture of R1132(E) and R1123. Examples of refrigerant 19 include a mixed refrigerant of R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, and R459A. The density of refrigerant 19 in gaseous form is greater than the density of air.

[0015] The outdoor unit 10 has a housing 11, a compressor 12, a heat exchanger 30, a throttling device 14, a blower 15, a four-way valve 16, and a control unit 17. The housing 11 houses the compressor 12, the heat exchanger 30, the throttling device 14, the blower 15, the four-way valve 16, and the control unit 17. The blower 15 generates an airflow that passes through the heat exchanger 30.

[0016] The compressor 12, the heat exchanger 30, the expansion device 14, and the four-way valve 16 are provided in a portion of the circulation path 18 that is located inside the housing 11. The compressor 12, the heat exchanger 30, the expansion device 14, and the four-way valve 16 are connected by a portion of the circulation path 18 that is located inside the housing 11.

[0017] The four-way valve 16 is provided in a portion of the circulation path section 18 that is connected to the discharge side of the compressor 12. The four-way valve 16 can reverse the direction of the refrigerant 19 flowing through the circulation path section 18 by switching a portion of the path of the circulation path section 18. When the path connected by the four-way valve 16 is the path shown by the solid line on the four-way valve 16 in Fig. 1, the refrigerant 19 flows through the circulation path section 18 in the direction shown by the solid arrow in Fig. 1. On the other hand, when the path connected by the four-way valve 16 is the path shown by the dashed line on the four-way valve 16 in Fig. 1, the refrigerant 19 flows through the circulation path section 18 in the direction shown by the dashed arrow in Fig. 1.

[0018] The indoor unit 20 includes a housing 21, a heat exchanger 22, and a blower 23. The housing 21 houses the heat exchanger 22 and the blower 23 inside. The blower 23 generates an airflow that passes through the heat exchanger 22. The indoor unit 20 is capable of cooling operation to cool the air in the room where the indoor unit 20 is located, and heating operation to warm the air in the room where the indoor unit 20 is located.

[0019] When the indoor unit 20 is in cooling operation, the refrigerant 19 flowing in the circulation path portion 18 flows in the direction shown by the solid arrow in Fig. 1. In other words, when the indoor unit 20 is in cooling operation, the refrigerant 19 flowing in the circulation path portion 18 circulates through the compressor 12, the heat exchanger 30 of the outdoor unit 10, the expansion device 14, and the heat exchanger 22 of the indoor unit 20 in that order, before returning to the compressor 12. During cooling operation, the heat exchanger 30 of the outdoor unit 10 functions as a condenser, and the heat exchanger 22 of the indoor unit 20 functions as an evaporator.

[0020] On the other hand, when the indoor unit 20 is in heating operation, the refrigerant 19 flowing in the circulation path portion 18 flows in the direction shown by the dashed line in Fig. 1. In other words, when the indoor unit 20 is in heating operation, the refrigerant 19 flowing in the circulation path portion 18 circulates through the compressor 12, the heat exchanger 22 of the indoor unit 20, the expansion device 14, and the heat exchanger 30 of the outdoor unit 10 in that order, before returning to the compressor 12. In heating operation, the heat exchanger 30 of the outdoor unit 10 functions as an evaporator, and the heat exchanger 22 of the indoor unit 20 functions as a condenser.

[0021] The state change of the refrigerant 19 flowing through the circulation path 18 during heating operation will be described in more detail. During heating operation, low-temperature, low-pressure gaseous refrigerant 19 is drawn into the compressor 12 and becomes high-temperature, high-pressure gaseous refrigerant 19. The high-temperature, high-pressure gaseous refrigerant 19 is discharged from the compressor 12, passes through the four-way valve 16, and flows into the heat exchanger 22 of the indoor unit 20. The high-temperature, high-pressure gaseous refrigerant 19 that flows into the heat exchanger 22 exchanges heat with air supplied from the blower 23 of the indoor unit 20, releasing heat and condensing, becoming high-temperature, high-pressure liquid refrigerant 19 that flows out of the heat exchanger 22. Thus, during heating operation, the heat exchanger 22 of the indoor unit 20 functions as a condenser. The liquid refrigerant 19 that flows out of the heat exchanger 22 is expanded and decompressed by the expansion device 14, becoming low-temperature, low-pressure, two-phase gas-liquid refrigerant 19, which flows into the heat exchanger 30 of the outdoor unit 10. The refrigerant 19 in a gas-liquid two-phase state that flows into the heat exchanger 30 absorbs heat and evaporates by exchanging heat with outdoor air supplied by the blower 15 of the outdoor unit 10, becoming low-temperature, low-pressure gaseous refrigerant 19 that flows out of the heat exchanger 30. In this way, the heat exchanger 30 of the outdoor unit 10 functions as an evaporator during heating operation. The low-temperature, low-pressure gaseous refrigerant 19 that flows out of the heat exchanger 30 is drawn back into the compressor 12, compressed again, and discharged. During heating operation, the above-described circulation of the refrigerant 19 is repeated.

[0022] The change in the state of the refrigerant 19 during cooling operation is similar to the change in the state of the refrigerant 19 during heating operation, except that the heat exchanger 30 of the outdoor unit 10 functions as a condenser and the heat exchanger 22 of the indoor unit 20 functions as an evaporator.

[0023] Next, the heat exchanger 30 of the outdoor unit 10 will be described in more detail. Fig. 2 is a partial cross-sectional view schematically showing a part of the heat exchanger 30. As shown in Fig. 2, the heat exchanger 30 includes a heat exchanger body 30a, a first refrigerant header 60, and a second refrigerant header 70.

[0024] The heat exchanger body 30a is a portion where heat exchange occurs between the refrigerant 19 and the air. The heat exchanger body 30a has a first heat exchange section 31 and a second heat exchange section 32. The first heat exchange section 31 is a main heat exchange section. The second heat exchange section 32 is a sub-heat exchange section. Note that while FIG. 2 shows the first heat exchange section 31 and the second heat exchange section 32 separated from each other in the left-right direction Y, the second heat exchange section 32 may be disposed below the first heat exchange section 31.

[0025] The first heat exchange unit 31 has a plurality of refrigerant path sections 40 that are separated from one another, and a plurality of heat transfer fins 31a provided in each refrigerant path section 40. The plurality of refrigerant path sections 40 are arranged side by side in the vertical direction Z. In the first embodiment, four refrigerant path sections 40 are provided. Each of the plurality of refrigerant path sections 40 has at least one heat transfer tube 40a and a third refrigerant header 71. In the first embodiment, each refrigerant path section 40 is provided with a plurality of heat transfer tubes 40a that are arranged side by side in the vertical direction Z. In the example of FIG. 2, each refrigerant path section 40 is provided with four heat transfer tubes 40a.

[0026] The heat transfer tubes 40a in each refrigerant path section 40 extend in the left-right direction Y. Each heat transfer tube 40a connects the second refrigerant header 70 and a third refrigerant header 71 provided in each refrigerant path section 40. Refrigerant 19 flows through the heat transfer tubes 40a of each refrigerant path section 40. The heat transfer tubes 40a are, for example, flat tubes whose dimensions in the vertical direction Z are smaller than their dimensions in the front-rear direction X. The upper and lower surfaces of the heat transfer tubes 40a are flat surfaces perpendicular to the vertical direction Z. A plurality of heat transfer fins 31a are connected to each heat transfer tube 40a and arranged at intervals in the left-right direction Y. The heat transfer fins 31a promote heat exchange in each heat transfer tube 40a. Note that the heat transfer tubes 40a may have bent portions in the vertical direction Z, the front-rear direction X, or the like.

[0027] The second heat exchange unit 32 has a plurality of heat transfer tubes 51, 52, 53, and 54 and a plurality of heat transfer fins 32a. In the first embodiment, the number of heat transfer tubes 51 to 54 provided in the second heat exchange unit 32 is smaller than the number of heat transfer tubes 40a provided in the first heat exchange unit 31. The plurality of heat transfer tubes 51 to 54 are connected to a first refrigerant header 60. In the first embodiment, the plurality of heat transfer tubes 51 to 54 extend to the right from the first refrigerant header 60. The plurality of heat transfer tubes 51 to 54 are arranged side by side at intervals in the vertical direction Z. The heat transfer tube 51, the heat transfer tube 52, the heat transfer tube 53, and the heat transfer tube 54 are arranged side by side in this order from bottom to top. Each of the heat transfer tubes 51 to 54 is connected to a third refrigerant header 71 of each refrigerant path unit 40 via a connection pipe 55. A plurality of heat transfer fins 32a are connected to each of the heat transfer tubes 51 to 54 and are arranged at intervals in the left-right direction Y. The heat transfer fins 32a promote heat exchange in each of the heat transfer tubes 51 to 54. A refrigerant 19 flows inside each of the heat transfer tubes 51 to 54.

[0028] Figure 3 is a cross-sectional view showing the first refrigerant header 60. Figure 3 shows a cross-sectional view of the first refrigerant header 60 cut in the vertical direction Z. Figure 4 is a cross-sectional view showing the first refrigerant header 60, taken along line IV-IV in Figure 3. Note that although two IV-IV cross sections are shown in Figure 3, the cross sections at both locations have the same shape, and so are shown together in Figure 4.

[0029] 3 and 4, in the first embodiment, each of the heat transfer tubes 51 to 54 is a flat tube whose dimension T in the vertical direction Z is smaller than its dimension W in the front-rear direction X, which is perpendicular to both the left-right direction Y and the vertical direction Z, along which each of the heat transfer tubes 51 to 54 extends. The upper and lower surfaces of each of the heat transfer tubes 51 to 54 are flat surfaces perpendicular to the vertical direction Z.

[0030] The first refrigerant header 60 is a liquid header into which the refrigerant 19 in a gas-liquid two-phase state flows. The first refrigerant header 60 can distribute the refrigerant 19 flowing in from the connected refrigerant pipe 81 to the multiple heat transfer tubes 51-54. As shown in FIG. 3 , the first refrigerant header 60 has a first orifice plate 61, a second orifice plate 62, and a header main body 63. The header main body 63 has a cylindrical shape extending in the vertical direction Z. More specifically, the header main body 63 has a cylindrical shape extending in the vertical direction Z. The header main body 63 has a bottom wall 63a, a top wall 63b, and a peripheral wall 63c. The peripheral wall 63c has a cylindrical shape extending in the vertical direction Z. The lower end of the peripheral wall 63c is closed by the bottom wall 63a. The upper end of the peripheral wall 63c is closed by the top wall 63b. The header body 63 may have a tubular shape other than a cylindrical shape.

[0031] The header main body 63 is formed with a plurality of connection holes 56a, 56b, 56c, and 56d to which the plurality of heat transfer tubes 51, 52, 53, and 54 are respectively connected. In the first embodiment, the plurality of connection holes 56a to 56d are formed in the peripheral wall 63c of the header main body 63. The plurality of connection holes 56a to 56d penetrate the right portion of the peripheral wall 63c from the inner circumferential surface to the outer circumferential surface. The plurality of connection holes 56a to 56d are arranged at intervals in the vertical direction Z. The connection holes 56a, 56b, 56c, and 56d are arranged in this order from bottom to top.

[0032] The distance G2 in the vertical direction Z between connection holes 56b and 56c is larger than the distance G1 in the vertical direction Z between connection holes 56a and 56b and the distance G3 in the vertical direction Z between connection holes 56c and 56d. The distance G1 in the vertical direction Z between connection holes 56a and 56b and the distance G3 in the vertical direction Z between connection holes 56c and 56d are the same. The distance G2 is, for example, at least twice the distances G1 and G3. More preferably, the distance G2 is, for example, at least three times the distances G1 and G3. In the first embodiment, the distances G1 and G3 are the smallest distances among the distances in the vertical direction Z between the multiple connection holes 56a to 56d. The distance G2 is the largest distance among the distances in the vertical direction Z between the multiple connection holes 56a to 56d. In the first embodiment, the intervals G1 and G3 correspond to the "first interval", and the interval G2 corresponds to the "second interval".

[0033] The header main body 63 is connected to the heat transfer tubes 51 to 54 included in the second heat exchange section 32. The heat transfer tubes 51 to 54 included in the second heat exchange section 32 are connected to connection holes 56a to 56d formed in the peripheral wall 63c of the header main body 63. The heat transfer tube 51 is inserted into and connected to the connection hole 56a. The heat transfer tube 52 is inserted into and connected to the connection hole 56b. The heat transfer tube 53 is inserted into and connected to the connection hole 56c. The heat transfer tube 54 is inserted into and connected to the connection hole 56d.

[0034] One end of each of the heat transfer tubes 51 to 54 is inserted into the header main body 63. In the first embodiment, the one end of the heat transfer tubes 51 to 54 inserted into the header main body 63 is the left end. The multiple heat transfer tubes 51 to 54 are connected to the header main body 63 from the right side in the left-right direction Y that intersects with the vertical direction Z. Each of the heat transfer tubes 51 to 54 penetrates a right-side portion of the peripheral wall 63c in the left-right direction Y via each of the connection holes 56a to 56d, and protrudes to the left from the inner circumferential surface of the peripheral wall 63c.

[0035] The header main body 63 may be manufactured, for example, by press-molding a part that forms the side (+Y side) to which the heat transfer tubes 51-54 are connected and a part that forms the side (-Y side) to which the refrigerant piping 81 is connected, and then connecting these two parts to each other. By combining two parts, the header main body 63 can be easily configured to accommodate the first orifice plate 61 and the second orifice plate 62 inside the header main body 63, facilitating assembly of the first refrigerant header 60. The header main body 63 may be manufactured by extrusion or by using a pipe.

[0036] The first orifice plate 61 and the second orifice plate 62 are located inside the header main body 63. In the first embodiment, the plate surfaces of the first orifice plate 61 and the second orifice plate 62 face the vertical direction Z. The first orifice plate 61 and the second orifice plate 62 are, for example, flat plates whose plate surfaces are perpendicular to the vertical direction. As shown in FIG. 4 , the outer shapes of the first orifice plate 61 and the second orifice plate 62 are shaped to conform to the inner circumferential surface of the header main body 63 when viewed in the vertical direction Z. In the first embodiment, the first orifice plate 61 and the second orifice plate 62 are circular. The outer peripheral edge of the first orifice plate 61 and the outer peripheral edge of the second orifice plate 62 are fixed to the inner circumferential surface of the peripheral wall portion 63 c. Note that the first orifice plate 61 and the second orifice plate 62 are not limited to flat plates. The first orifice plate 61 and the second orifice plate 62 may be plate-shaped with unevenness formed thereon, or the plate surfaces of the first orifice plate 61 and the second orifice plate 62 may be arranged at an incline with respect to a plane perpendicular to the vertical direction Z.

[0037] As shown in FIG. 3 , the first orifice plate 61 and the second orifice plate 62 are spaced apart in the vertical direction Z. The first orifice plate 61 is spaced apart above the bottom wall portion 63a. The second orifice plate 62 is spaced apart above the first orifice plate 61. The second orifice plate 62 is spaced apart below the top wall portion 63b. The second orifice plate 62 is located between the connecting holes 56b and 56c spaced apart by the distance G2 in the vertical direction Z. In other words, the position of the second orifice plate 62 in the vertical direction Z is the position in the vertical direction Z between the connecting holes 56b and 56c spaced apart by the distance G2. The second orifice plate 62 is located between the portions of the heat transfer tubes 52 inserted into the header main body 63 and the portions of the heat transfer tubes 53 inserted into the header main body 63. The distance in the vertical direction Z between the second orifice plate 62 and the heat transfer tube 53 located above the second orifice plate 62 is larger than the distance in the vertical direction Z between the heat transfer tube 53 and the heat transfer tube 54. The distance in the vertical direction Z between the heat transfer tube 53 and the heat transfer tube 54 is equal to the distance G3 in the vertical direction Z between the connection holes 56c and 56d. In the first embodiment, the second orifice plate 62 is located below the center in the vertical direction Z between the connection holes 56b and 56c that are spaced apart by the distance G2.

[0038] The distance in the vertical direction Z between the first orifice plate 61 and the second orifice plate 62 and the distance in the vertical direction Z between the top wall portion 63b and the second orifice plate 62 are greater than the distance in the vertical direction Z between the bottom wall portion 63a and the first orifice plate 61. The distance in the vertical direction Z between the first orifice plate 61 and the second orifice plate 62 and the distance in the vertical direction Z between the top wall portion 63b and the second orifice plate 62 may be the same as or different from each other.

[0039] The first orifice plate 61 and the second orifice plate 62 divide the internal space of the header main body 63 into three spaces aligned in the vertical direction Z. The first orifice plate 61 and the second orifice plate 62 divide the internal space of the header main body 63 into a first space 64a, a second space 64b, and a third space 64c. The first space 64a is the space between the bottom wall portion 63a and the first orifice plate 61 in the vertical direction Z. The second space 64b is the space between the first orifice plate 61 and the second orifice plate 62 in the vertical direction Z. The third space 64c is the space between the second orifice plate 62 and the top wall portion 63b in the vertical direction Z. The second space 64b is located above the first space 64a. The third space 64c is located above the second space 64b. The first space 64a and the second space 64b are separated by a first orifice plate 61. The second space 64b and the third space 64c are separated by a second orifice plate 62.

[0040] A refrigerant pipe 81 is connected to the first space 64a. The refrigerant pipe 81 is a pipe through which the refrigerant 19 flows, flowing into or out of the header main body 63. The refrigerant pipe 81 is connected to the header main body 63. More specifically, the refrigerant pipe 81 is connected to the lower end of the peripheral wall portion 63c of the header main body 63 from the left side. That is, the refrigerant pipe 81 is connected to the header main body 63 from the side opposite to the side to which the heat transfer tubes 51 to 54 are connected. The portion of the header main body 63 to which the refrigerant pipe 81 is connected is located below the lowest heat transfer tube 51 of the multiple heat transfer tubes 51 to 54 connected to the first refrigerant header 60. Note that the refrigerant pipe 81 may be connected to any part of the first refrigerant header 60 as long as it is connected to the first space 64a. The refrigerant pipe 81 may be connected to a hole formed in the bottom wall portion 63a. None of the heat transfer tubes 51 to 54 are connected to the first space 64a. The first space 64 a is located below the heat transfer tubes 51 to 54 connected to the first refrigerant header 60 .

[0041] The heat transfer tubes 51 and 52 are connected to the second space 64b. The heat transfer tubes 51 and 52 protrude into the second space 64b and open into the second space 64b. In the first embodiment, the left ends of the heat transfer tubes 51 and 52 are located to the left of the center of the header main body 63 in the left-right direction Y. In the first embodiment, the center of the header main body 63 in the left-right direction Y is the center of the cylindrical peripheral wall portion 63c. Note that the left ends of the heat transfer tubes 51 and 52 may be located at the same position in the left-right direction Y as the center of the header main body 63 in the left-right direction Y, or may be located to the right of the center of the header main body 63 in the left-right direction Y.

[0042] The third space 64c is connected to a heat transfer tube 53 and a heat transfer tube 54 that are different from the heat transfer tubes 51 and 52 connected to the second space 64b. That is, different heat transfer tubes among the heat transfer tubes 51 to 54 are connected to the second space 64b and the third space 64c. The heat transfer tubes 53 and 54 protrude into the third space 64c and open into the third space 64c. In the first embodiment, the left ends of the heat transfer tubes 53 and 54 are located to the left of the center of the header main body 63 in the left-right direction Y. The left ends of the heat transfer tubes 53 and 54 may be located at the same position as the center of the header main body 63 in the left-right direction Y, or may be located to the right of the center of the header main body 63 in the left-right direction Y.

[0043] The dimension of the first space 64a in the vertical direction Z is smaller than the dimension of the second space 64b in the vertical direction Z and the dimension of the third space 64c in the vertical direction Z. By reducing the dimension of the first space 64a in the vertical direction Z, the space provided below the lowermost heat transfer tube 51 of the multiple heat transfer tubes 51 to 54 connected to the first refrigerant header 60 can be reduced in the vertical direction Z. This makes it possible to prevent the heat exchanger 30 from becoming larger in the vertical direction Z.

[0044] The dimension of the second space 64b in the vertical direction Z and the dimension of the third space 64c in the vertical direction Z may be the same as or different from each other. The volume of the first space 64a is smaller than the volumes of the second space 64b and the third space 64c. The volume of the second space 64b and the volume of the third space 64c may be the same as or different from each other. Note that the size relationship between the dimensions and volumes of the first space 64a, the second space 64b, and the third space 64c in the vertical direction Z is not particularly limited, and any size relationship may be possible.

[0045] A first orifice hole 61a is formed in the first orifice plate 61. The first orifice hole 61a penetrates the first orifice plate 61 in the vertical direction Z. The first orifice hole 61a opens to the first space 64a and the second space 64b. The first space 64a and the second space 64b are connected to each other via the first orifice hole 61a. In other words, the first orifice hole 61a is a through hole connecting the first space 64a and the second space 64b. As shown in FIG. 4 , in the first embodiment, the first orifice hole 61a is a circular hole. In the first embodiment, two first orifice holes 61a are provided side by side in the front-rear direction X. The shape of the first orifice hole 61a is not particularly limited and may be any shape.

[0046] In the first embodiment, the first orifice hole 61a is formed in a portion of the first orifice plate 61 that is located to the left of the center in the left-right direction Y. That is, the first orifice hole 61a is positioned offset toward the side opposite (negative Y side) from the side where the heat transfer tubes 51, 52 are connected to the header main body 63. The first orifice hole 61a is positioned to the left of the left ends of the heat transfer tubes 51, 52 inserted into the second space 64b. When the portions of the heat transfer tubes 51, 52 connected to the second space 64b that are located within the second space 64b are projected onto the first orifice plate 61 in the vertical direction Z, the first orifice hole 61a is formed in a region of the first orifice plate 61 that is different from the region onto which the heat transfer tubes 51, 52 are projected. That is, the first orifice hole 61a is positioned so as not to overlap the heat transfer tubes 51, 52 connected to the second space 64b in the vertical direction Z.

[0047] As shown in FIG. 3 , a second orifice hole 62a is formed in the second orifice plate 62. The second orifice hole 62a penetrates the second orifice plate 62 in the vertical direction Z. The second orifice hole 62a opens to the second space 64b and the third space 64c. The second space 64b and the third space 64c are connected to each other via the second orifice hole 62a. In other words, the second orifice hole 62a is a through-hole connecting the second space 64b and the third space 64c. As shown in FIG. 4 , in the first embodiment, the second orifice hole 62a is a circular hole. In the first embodiment, two second orifice holes 62a are provided side by side in the front-rear direction X. The shape of the second orifice hole 62a is not particularly limited and may be any shape.

[0048] In the first embodiment, each second orifice hole 62a is provided at a position where it overlaps with each first orifice hole 61a when viewed in the vertical direction Z. Note that the first orifice hole 61a and the second orifice hole 62a may be provided at a position where they do not overlap when viewed in the vertical direction Z.

[0049] In the first embodiment, the second orifice hole 62a is formed in a portion of the second orifice plate 62 located to the left of the center in the left-right direction Y. In other words, the second orifice hole 62a is positioned offset toward the side opposite (the -Y side) from the side where the heat transfer tubes 53, 54 are connected to the header main body 63. The second orifice hole 62a is positioned to the left of the left ends of the heat transfer tubes 53, 54 inserted in the third space 64c. When the portions of the heat transfer tubes 53, 54 connected to the third space 64c that are located within the third space 64c are projected onto the second orifice plate 62 in the vertical direction Z, the second orifice hole 62a is formed in a region of the second orifice plate 62 that is different from the region onto which the heat transfer tubes 53, 54 are projected. In other words, the second orifice hole 62a is positioned so as not to overlap the heat transfer tubes 53, 54 connected to the third space 64c in the vertical direction Z.

[0050] The cross-sectional areas of the first and second orifice holes 61a and 62a are, for example, smaller than one-third of the cross-sectional area of ​​the interior of the header main body 63 in a cross section perpendicular to the vertical direction Z. In the first embodiment, the cross-sectional areas of the orifice holes 61a and 62a are the cross-sectional areas of the orifice holes 61a and 62a in a cross section perpendicular to the vertical direction Z. In the first embodiment, the cross-sectional areas of the orifice holes 61a and 62a are smaller than the flow path cross-sectional area of ​​the refrigerant pipe 81. In the first embodiment, when the cross-sectional area of ​​each of the orifice holes 61a and 62a is A1 and the flow path cross-sectional area of ​​the refrigerant pipe 81 is A2, the relationship 0.15<A1 / A2<0.4 is satisfied. In other words, the cross-sectional area of ​​each of the orifice holes 61a and 62a is greater than 15% and less than 40% of the flow path cross-sectional area of ​​the refrigerant pipe 81.

[0051] The cross-sectional area of ​​each of the orifice holes 61a, 62a is, for example, smaller than the flow path cross-sectional area of ​​each of the heat transfer tubes 51 to 54 connected to the first refrigerant header 60. The flow path cross-sectional area of ​​each of the heat transfer tubes 51 to 54 is smaller than the flow path cross-sectional area of ​​the refrigerant piping 81. The cross-sectional area of ​​the first orifice hole 61a and the cross-sectional area of ​​the second orifice hole 62a may be the same as or different from each other.

[0052] The first orifice plate 61 and the second orifice plate 62 may be orifice plates having the same specifications, or may be orifice plates having different specifications. The specifications of the orifice plate include the size (cross-sectional area) of the orifice holes formed in the orifice plate, the position of the orifice holes, and the thickness of the orifice plate. By making the first orifice plate 61 and the second orifice plate 62 orifice plates having the same specifications, the number of types of parts of the heat exchanger 30 can be reduced, and the manufacturing cost of the heat exchanger 30 can be reduced.

[0053] The second refrigerant header 70 is a gas header into which the gaseous refrigerant 19 flows. As shown in FIG. 2 , the second refrigerant header 70 is tubular and extends in the vertical direction Z. Both ends of the second refrigerant header 70 in the vertical direction Z are closed. A refrigerant pipe 82 is connected to the second refrigerant header 70. The refrigerant pipe 82 is a pipe through which the refrigerant 19 flows when it flows into or out of the second refrigerant header 70. The refrigerant pipe 82 is connected to a peripheral wall portion of the second refrigerant header 70. The refrigerant pipe 82 may be connected to any location on the second refrigerant header 70. Each heat transfer tube 40a provided in each refrigerant path portion 40 is connected to a peripheral wall portion of the second refrigerant header 70. The second refrigerant header 70 is connected to the first refrigerant header 60 via a plurality of refrigerant path portions 40.

[0054] During heating operation in which the heat exchanger 30 functions as an evaporator, the refrigerant 19 flows from the refrigerant pipe 81 into the first space 64a of the first refrigerant header 60. At this time, the refrigerant 19 flowing into the first space 64a is in a gas-liquid two-phase state. The refrigerant 19 that flows into the first space 64a flows into the second space 64b through the first orifice hole 61a. At this time, the refrigerant 19 is blown upward from the first orifice hole 61a and flows into the second space 64b. In the first embodiment, the first orifice hole 61a is positioned so as not to overlap with the first heat transfer tubes 51 and 52 in the vertical direction Z, thereby preventing the flow of the refrigerant 19 blown upward from the first orifice hole 61a within the second space 64b from being obstructed by the heat transfer tubes 51 and 52. The velocity of the refrigerant 19 that flows into the second space 64b through the first orifice hole 61a is higher than the velocity of the refrigerant 19 in the first space 64a due to the narrowing of the flow path cross-sectional area at the first orifice hole 61a.

[0055] A portion of the refrigerant 19 that flows from the first space 64a to the second space 64b flows into the heat transfer tubes 51, 52 connected to the second space 64b. The refrigerant 19 that flows into each of the heat transfer tubes 51, 52 flows through each of the connection pipes 55 to the third refrigerant header 71 of each of the refrigerant path sections 40, and branches from the third refrigerant header 71 to flow into the heat transfer tubes 40a.

[0056] The remainder of the refrigerant 19 that flows from the first space 64a to the second space 64b flows into the third space 64c through the second orifice hole 62a. At this time, the refrigerant 19 is blown upward from the second orifice hole 62a and flows into the third space 64c. In the first embodiment, the second orifice hole 62a is provided at a position that does not overlap with the heat transfer tubes 53, 54 in the vertical direction Z, so that the flow of the refrigerant 19 blown upward from the second orifice hole 62a in the third space 64c is prevented from being obstructed by the heat transfer tubes 53, 54. The refrigerant 19 that flows into the third space 64c flows into the heat transfer tubes 53, 54 connected to the third space 64c. The refrigerant 19 that flows into each heat transfer tube 53, 54 flows through each connecting pipe 55 to each third refrigerant header 71 of each refrigerant path section 40, and branches from each third refrigerant header 71 to flow into the interior of multiple heat transfer tubes 40a.

[0057] The refrigerant 19 branching off and flowing through each heat transfer tube 40a merges inside the second refrigerant header 70 and flows out of the second refrigerant header 70 through a refrigerant pipe 82 connected to the second refrigerant header 70. The refrigerant 19 flowing through each heat transfer tube 40a, 51-54 exchanges heat with the fluid flowing outside the heat transfer tubes 51-54, 40a, i.e., the air in the airflow generated by the blower 15. When the heat exchanger 30 functions as an evaporator, the refrigerant 19 flowing into the first refrigerant header 60 in a gas-liquid two-phase state undergoes heat exchange in each heat transfer tube 51-54, 40a, becoming gaseous refrigerant 19 and flowing out of the refrigerant pipe 82 of the second refrigerant header 70. Note that if a small amount of heat exchange in the heat exchanger main body 30a is not a problem, for example, the multiple heat transfer tubes 51-54 connected to the first refrigerant header 60 may be connected to the second refrigerant header 70 without the first heat exchange section 31.

[0058] When the heat exchanger 30 functions as an evaporator, the first refrigerant header 60 functions as a distributor that distributes the refrigerant 19 flowing in from the refrigerant pipe 81 to the multiple heat transfer tubes 51 to 54. When the heat exchanger 30 functions as an evaporator, the second refrigerant header 70 functions as a mixer that collects the refrigerant 19 that is further branched from the multiple heat transfer tubes 51 to 54 to the multiple heat transfer tubes 40a. When the heat exchanger 30 functions as a condenser, the first refrigerant header 60 functions as a mixer that collects the refrigerant 19 flowing in the multiple heat transfer tubes 51 to 54. When the heat exchanger 30 functions as a condenser, the second refrigerant header 70 functions as a distributor that distributes the refrigerant 19 flowing in from the refrigerant pipe 82 to the multiple heat transfer tubes 40a.

[0059] In the first refrigerant header 60 of the first embodiment, the number of times that the refrigerant passes through the orifice holes before flowing from the refrigerant pipe 81 into the heat transfer tubes 51 to 54 differs between the heat transfer tubes 51, 52 connected to the second space 64b and the heat transfer tubes 53, 54 connected to the third space 64c. The refrigerant 19 flowing into the heat transfer tubes 53, 54 connected to the third space 64c, which is located above the second space 64b, passes through the orifice holes more times than the refrigerant 19 flowing into the heat transfer tubes 51, 52 connected to the second space 64b.

[0060] When the flow rate of the refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is low, the flow velocity of the refrigerant 19 flowing from the first space 64a through the first orifice hole 61a into the second space 64b is relatively low, and the flow resistance that the refrigerant 19 experiences at the second orifice hole 62a is relatively low. Therefore, the refrigerant 19 that flows into the second space 64b easily passes through the second orifice hole 62a. Note that the refrigerant 19 that flows into the third space 64c through the second orifice hole 62a falls due to the influence of gravity, and remains on the upper surface of the second orifice plate 62. The refrigerant 19 then flows again through the third space 64c due to the refrigerant 19 passing through the second orifice hole 62a.

[0061] On the other hand, when the flow rate of refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is high, the flow velocity of refrigerant 19 flowing from the first space 64a through the first orifice hole 61a into the second space 64b is relatively high, and the flow resistance that the refrigerant 19 experiences at the second orifice hole 62a is relatively high. Therefore, the refrigerant 19 that has flowed into the second space 64b is less likely to pass through the second orifice hole 62a. This makes it more difficult for the refrigerant 19 to flow into the third space 64c.

[0062] 5 is a diagram showing an example of the refrigerant distribution amount in a first refrigerant header 160 of a comparative example. As shown in FIG. 5, the first refrigerant header 160 of comparative example 1 is not provided with a second orifice plate 62. In the first refrigerant header 160, the multiple heat transfer tubes 51 to 54 are connected to a space 164b above the first orifice plate 61 within the internal space of the header main body 63. The other configurations of the first refrigerant header 160 are the same as those of the first refrigerant header 60 described above.

[0063] 5 shows the flow rates distributed to the heat transfer tubes 51-54 in a high flow rate state in which a relatively large amount of refrigerant 19 flows from the refrigerant pipe 81 into the first space 64a of the first refrigerant header 160, and in a low flow rate state in which a relatively small amount of refrigerant 19 flows from the refrigerant pipe 81 into the first space 64a. The high flow rate state is a state in which the flow rate of refrigerant 19 flowing into the first space 64a is equal to or close to the flow rate of refrigerant when the refrigeration cycle apparatus in which the first refrigerant header 160 is installed is operating at rated capacity. The low flow rate state is a state in which the flow rate of refrigerant 19 flowing into the first space 64a is equal to the flow rate of refrigerant when the refrigeration cycle apparatus in which the first refrigerant header 160 is installed is operating at a low load, in which the load on the refrigeration cycle apparatus is lower than when the refrigerant header 160 is operating at rated capacity.

[0064] In the first refrigerant header 160 of the comparative example, which does not have the second orifice plate 62, when the flow rate is low (low load), the liquid refrigerant 19 in the gas-liquid two-phase state tends to fall downward due to the effect of gravity. As a result, the liquid refrigerant 19 tends to accumulate unevenly in the lower part of the space 164b of the first refrigerant header 160. As a result, when the flow rate is low, the flow rate of the refrigerant 19 distributed to the heat transfer tubes 51 to 54 connected to the space 164b of the first refrigerant header 160 is greater for the heat transfer tubes located lower.

[0065] On the other hand, in the first refrigerant header 160 of the comparative example, at high flow rates (high loads), the velocity of the refrigerant 19 flowing from the first space 64a into the space 164b is sufficiently high, so that the liquid refrigerant 19 tends to flow upward in the space 164b. As a result, at high flow rates, the flow rate of the refrigerant 19 distributed to the heat transfer tubes 51 to 54 connected to the space 164b of the first refrigerant header 160 is greater for the heat transfer tubes located at the top.

[0066] As described above, in the first refrigerant header 160 of the comparative example, fluctuations in the flow rate of the refrigerant 19 flowing into the first space 64a, i.e., fluctuations in the load on the refrigeration cycle device, cause differences in the amount of refrigerant 19 distributed from the first refrigerant header 160 to the plurality of heat transfer tubes 51 to 54. As a result, the energy efficiency of the heat exchanger is likely to decrease.

[0067] 5 shows a first refrigerant header 160 in which the second orifice plate 62 is removed from the first refrigerant header 60 as a comparative example, but even in a first refrigerant header in which the first orifice plate 61 is removed from the first refrigerant header 60, the distribution characteristics of the refrigerant 19 are similar to those shown in Fig. 5. Furthermore, when the first orifice plate 61 is not provided and only the second orifice plate 62 is provided, the rate at which the refrigerant 19 rises decreases, and the amount of refrigerant 19 distributed to the heat transfer tubes connected to the space located below the second orifice plate 62 increases significantly.

[0068] In response to the above problem, according to the first embodiment, the heat exchanger 30 is a heat exchanger for the refrigeration cycle apparatus 100 and includes a plurality of heat transfer tubes 51-54 and a first refrigerant header 60 to which the refrigerant pipe 81 and the plurality of heat transfer tubes 51-54 are connected and which can distribute the refrigerant 19 flowing in from the refrigerant pipe 81 to the plurality of heat transfer tubes 51-54. The first refrigerant header 60 includes a cylindrical header main body 63 extending in the vertical direction Z, a first orifice plate 61 located inside the header main body 63 and having a first orifice hole 61a formed therein, and a second orifice plate 62 located inside the header main body 63 and having a second orifice hole 62a formed therein. The internal space of the header main body 63 is partitioned by the first orifice plate 61 and the second orifice plate 62 into a first space 64a, a second space 64b, and a third space 64c. The first space 64a and the second space 64b are connected to each other via the first orifice hole 61a. The second space 64b and the third space 64c are connected to each other via the second orifice hole 62a. The second space 64b is located vertically above the first space 64a. The third space 64c is located vertically above the second space 64b. A refrigerant pipe 81 is connected to the first space 64a. Different heat transfer tubes from the plurality of heat transfer tubes 51 to 54 are connected to the second space 64b and the third space 64c.

[0069] According to the above configuration, as described above, when the flow rate of the refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is low, the refrigerant 19 can pass through the second orifice hole 62a relatively easily. However, when the flow rate of the refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is high, the refrigerant 19 can pass through the second orifice hole 62a with difficulty. Therefore, the refrigerant 19, which tends to flow downward due to gravity at low flow rates, tends to flow through the second orifice hole 62a to the third space 64c, which is located above the second space 64b. This prevents the refrigerant 19 from being unevenly distributed to the lower heat transfer tubes 51 and 52 at low flow rates. Furthermore, when the flow rate is high, the refrigerant 19, which tends to flow upward due to acceleration at the first orifice hole 61a, can be prevented from passing through the second orifice hole 62a. This prevents excessive flow of the refrigerant 19 into the third space 64c, which is located above the second space 64b. This prevents the refrigerant 19 from being unevenly distributed to the upper heat transfer tubes 53, 54 at high flow rates. Therefore, even if the flow rate of the refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a fluctuates, differences in the amounts of refrigerant 19 distributed to the heat transfer tubes 51 to 54 can be prevented. Therefore, regardless of the flow rate of the refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a, changes in the distribution ratio of the refrigerant 19 to the plurality of heat transfer tubes 51 to 54 can be prevented. Therefore, the energy efficiency of the heat exchanger 30 can be improved over the entire range of loads applied to the refrigeration cycle apparatus 100, for example.

[0070] Furthermore, the first refrigerant header 60 can be formed simply by arranging the first orifice plate 61 and the second orifice plate 62, each having orifice holes formed therein, inside the cylindrical header body 63. This allows the first refrigerant header 60 to have a simple structure. Therefore, according to the first embodiment, the first refrigerant header 60 with a simple structure can suppress changes in the distribution ratio of the refrigerant 19 to the plurality of heat transfer tubes 51-54 in the heat exchanger 30 of the refrigeration cycle apparatus 100.

[0071] Fig. 6 is a diagram showing an example of the refrigerant distribution amount in the first refrigerant header 60 according to Embodiment 1. Similar to Fig. 5, Fig. 6 shows the flow rates distributed to the heat transfer tubes 51 to 54 in a high flow rate state in which a relatively large amount of refrigerant 19 flows from the refrigerant pipe 81 into the first space 64a of the first refrigerant header 60, and in a low flow rate state in which a relatively small amount of refrigerant 19 flows from the refrigerant pipe 81 into the first space 64a.

[0072] As shown in Figure 6, in the first refrigerant header 60 of the first embodiment, it can be seen that the difference in the amount of refrigerant 19 distributed between low and high flow rates is smaller for each of the heat transfer tubes 51 to 54, compared to the first refrigerant header 160 of the comparative example shown in Figure 5. In other words, it can be seen that it is possible to suppress changes in the distribution ratio of refrigerant 19 to the multiple heat transfer tubes 51 to 54.

[0073] 6, although the refrigerant 19 is generally distributed uniformly to the heat transfer tubes 51 to 54, there is a tendency for the amount of refrigerant 19 distributed to the upper heat transfer tubes 53, 54 to be slightly greater than that to the lower heat transfer tubes 51, 52. However, if such a tendency is known in advance, it is possible to improve the overall energy efficiency of the heat exchanger 30 by configuring the heat exchanger 30 so that more refrigerant 19 is directed to heat transfer tubes where the amount of heat exchange is likely to be large, such as locations where a large amount of air passes through the heat exchanger 30, or by increasing the number of heat transfer tubes 40a branching off from the upper heat transfer tubes 53, 54.

[0074] In the example of Figure 2, the heat exchanger 30 is configured so that the refrigerant 19 flowing into the two heat transfer tubes 51, 52 connected to the second space 64b flows into the uppermost and lowermost refrigerant path sections 40 of the multiple refrigerant path sections 40. Also, in the example of Figure 2, the heat exchanger 30 is configured so that the refrigerant 19 flowing into the two heat transfer tubes 53, 54 connected to the third space 64c flows into the two refrigerant path sections 40 located at the center in the vertical direction Z. When the amount of air sent from the blower 15 to the first heat exchange section 31 is large in the refrigerant path section 40 located at the center in the vertical direction Z of the first heat exchange section 31, connecting the heat transfer tubes 51 to 54 as in the example of Figure 2 makes it easy to favorably improve the energy efficiency of the heat exchanger 30.

[0075] According to the first embodiment, the header main body 63 is formed with a plurality of connection holes 56a to 56d to which the plurality of heat transfer tubes 51 to 54 are respectively connected. The connection holes 56a to 56d are spaced apart in the vertical direction Z. The spacing between the connection holes 56a to 56d in the vertical direction Z includes first spacings G1 and G3 and a second spacing G2 that is larger than the first spacing. The second orifice plate 62 is located between the connection holes 56b and 56c that are spaced apart by the spacing G2 in the vertical direction Z. Therefore, the second orifice plate 62 can be disposed in a location where the spacing between the connection holes 56a to 56d is relatively large, i.e., where the spacing between the heat transfer tubes 51 to 54 connected to each connection hole 56a to 56d is relatively large. This makes it easy to arrange the second orifice plate 62 in the header main body 63, even when one ends of the heat transfer tubes 51 to 54 are inserted into the header main body 63, facilitating the manufacture of the first refrigerant header 60. Furthermore, when one ends of the heat transfer tubes 51 to 54 are inserted into the header main body 63, the distance between the second orifice plate 62 and the heat transfer tubes 52 and 53 that are arranged to sandwich the second orifice plate 62 in the vertical direction Z can be increased. Furthermore, the distance in the vertical direction Z between the second orifice plate 62 and the heat transfer tube 53 located above the second orifice plate 62 can be made larger than the distance in the vertical direction Z between the heat transfer tube 53 and the heat transfer tube 54. This makes it easy for the refrigerant 19 blown up into the third space 64c from the second orifice hole 62a to flow into the heat transfer tubes 53 and 54. In the first embodiment, the second orifice plate 62 is located below the center in the vertical direction Z between the connecting holes 56b, 56c that are arranged with a gap G2 between them. Therefore, the distance in the vertical direction Z between the second orifice plate 62 and the heat transfer tube 53 located above the second orifice plate 62 can be made larger than the distance in the vertical direction Z between the heat transfer tube 53 and the heat transfer tube 54. This makes it easier for the refrigerant 19 to flow into the heat transfer tubes 53, 54 in the third space 64c.

[0076] The second orifice plate 62 may be positioned above the center in the vertical direction Z between the connecting holes 56b, 56c that are arranged with a gap G2 between them. In this case, the second orifice plate 62 can be positioned closer in the vertical direction Z to the heat transfer tubes 53, 54 that are connected to the third space 64c. This makes it possible to facilitate the flow of the accumulated refrigerant 19 to both the heat transfer tube 53 and the heat transfer tube 54, even if the refrigerant 19 that has flowed into the third space 64c accumulates on the upper surface of the second orifice plate 62 due to gravity. This more effectively prevents a difference in the amount of refrigerant 19 flowing into the heat transfer tubes 53, 54 that are arranged side by side in the vertical direction Z.

[0077] According to the first embodiment, the heat transfer tubes 51 to 54 are connected to the header main body 63 from the right side (+Y side, first side) in the left-right direction Y (intersecting direction) that intersects with the vertical direction Z. The first orifice hole 61a is formed in a portion of the first orifice plate 61 that is located on the left side (-Y side, second side) opposite to the right side of the center in the left-right direction Y. The second orifice hole 62a is formed in a portion of the second orifice plate 62 that is located on the left side of the center in the left-right direction Y. Therefore, the refrigerant 19 that flows through at least one of the first orifice hole 61a and the second orifice hole 62a in the header main body 63 tends to flow unevenly toward the side opposite to the side to which the heat transfer tubes 51 to 54 are connected. This makes it easier for the refrigerant 19 flowing within the header main body 63 to flow from the side opposite to the side where the multiple heat transfer tubes 51 to 54 are connected to the side where the multiple heat transfer tubes 51 to 54 are connected, making it easier for the refrigerant 19 to flow into each heat transfer tube 51 to 54.

[0078] According to the first embodiment, one ends of the plurality of heat transfer tubes 51 to 54 are inserted inside the header main body 63. When the portions of the heat transfer tubes 51, 52 connected to the second space 64b that are located within the second space 64b are projected onto the first orifice plate 61 in the vertical direction Z, the first orifice hole 61a is formed in a region of the first orifice plate 61 that is different from the region onto which the portions of the heat transfer tubes 51, 52 are projected. Therefore, the first orifice hole 61a and the heat transfer tubes 51, 52 are positioned so as not to overlap with each other in the vertical direction Z, which prevents the refrigerant 19 blown upward from the first orifice hole 61a from colliding with and falling off the heat transfer tubes 51, 52. Furthermore, when the portions of the heat transfer tubes 53, 54 connected to the third space 64c that are located within the third space 64c are projected in the vertical direction Z onto the second orifice plate 62, the second orifice hole 62a is formed in a region different from the region onto which the portions of the heat transfer tubes 53, 54 are projected on the second orifice plate 62. Therefore, the second orifice hole 62a and the heat transfer tubes 53, 54 are positioned so as not to overlap each other in the vertical direction Z, and the refrigerant 19 blown upward from the second orifice hole 62a can be prevented from colliding with and falling against the heat transfer tubes 53, 54.

[0079] According to the first embodiment, the heat transfer tubes 51 to 54 are flat tubes whose dimension T in the vertical direction Z is smaller than their dimension W in the front-to-rear direction X, which is perpendicular to both the direction in which the heat transfer tubes 51 to 54 extend and the vertical direction Z. Therefore, if the heat transfer tubes 51 to 54 were arranged in a position where they overlap with the first orifice hole 61 a and the second orifice hole 62 a in the vertical direction Z, the refrigerant 19 would likely collide with and fall off the flat surfaces below the heat transfer tubes 51 to 54. Therefore, the above-described effect obtained by arranging the heat transfer tubes 51 to 54 in a position where they do not overlap with the orifice holes 61 a, 62 a in the vertical direction Z is particularly useful when the heat transfer tubes 51 to 54 are flat tubes.

[0080] Furthermore, when the heat transfer tubes 51 to 54 are flat tubes, by making each of the orifice holes 61a, 62a long in the longitudinal direction in the cross section of each of the heat transfer tubes 51 to 54, that is, in the front-to-rear direction X in the first embodiment, it is possible to make it easier for the refrigerant 19 that has passed through each of the orifice holes 61a, 62a to flow uniformly into each of the heat transfer tubes 51 to 54. In the first embodiment, by forming two orifice holes 61a, 62a side by side in the front-to-rear direction X, which is the longitudinal direction in the cross section of the heat transfer tubes 51 to 54, which are flat tubes, a configuration is achieved in which the shape of each of the orifice holes 61a, 62a is simple while achieving substantially the same effect as when each of the orifice holes 61a, 62a is long in the front-to-rear direction X.

[0081] According to the first embodiment, the cross-sectional areas of the first orifice hole 61a and the second orifice hole 62a are smaller than the flow path cross-sectional area of ​​the refrigerant pipe 81. As a result, when the amount of refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is small, the velocity of the refrigerant 19 passing through the first orifice hole 61a is easily increased, making it easier for the refrigerant 19 to flow into the third space 64c via the second orifice hole 62a. Furthermore, when the amount of refrigerant 19 flowing from the refrigerant pipe 81 into the first space 64a is small, the velocity of the refrigerant 19 flowing from the second orifice hole 62a into the third space 64c is easily increased, making it easier for the refrigerant 19 to flow upward within the third space 64c. As a result, the amount of refrigerant 19 distributed to each of the heat transfer tubes 51-54 is more uniform.

[0082] As described above, if the cross-sectional areas of the first orifice hole 61a and the second orifice hole 62a are appropriately small, the flow velocity of the refrigerant 19 passing through each of the orifice holes 61a, 62a can be appropriately increased when the flow rate of the refrigerant 19 is low, which has the effect of making it easier to raise the refrigerant 19 within the header main body 63. On the other hand, if the cross-sectional areas of the first orifice hole 61a and the second orifice hole 62a are too small, the flow resistance of the refrigerant 19 when passing through each of the orifice holes 61a, 62a becomes too large, which may result in large variations in the amount of refrigerant 19 distributed to each of the heat transfer tubes 51-54. In contrast, in the first embodiment, the cross-sectional areas of the first orifice hole 61a and the second orifice hole 62a are sized to satisfy the relationship 0.15<A1 / A2<0.4, where A1 is the cross-sectional area of ​​each of the orifice holes 61a and 62a and A2 is the flow path cross-sectional area of ​​the refrigerant pipe 81. By setting the cross-sectional areas of the first orifice hole 61a and the second orifice hole 62a to these sizes, the refrigerant 19 can be easily raised within the header main body 63 at low flow rates while suppressing large variations in the amount of refrigerant 19 distributed to the heat transfer tubes 51-54. The range of the cross-sectional areas of the orifices 61a and 62a that satisfies 0.15<A1 / A2<0.4 was newly discovered through experiments using an air conditioner incorporating the heat exchanger 30 of the present disclosure.

[0083] Embodiment 2. Fig. 7 is a partial cross-sectional view showing a part of a heat exchanger 230 according to embodiment 2. In the following description, the same components as those in the above-described embodiment will be denoted by the same reference numerals as appropriate, and the description thereof may be omitted.

[0084] As shown in FIG. 7 , in the heat exchanger 230, two heat transfer tubes 250b, a heat transfer tube 251 and a heat transfer tube 252, are connected to the second space 64b. The heat transfer tubes 251 and 252 are a pair of heat transfer tubes arranged side by side in the vertical direction Z. The pair of heat transfer tubes 251 and 252 connected to the second space 64b extend from the first refrigerant header 60 in the left-right direction Y intersecting the vertical direction Z and are folded back in a direction away from each other in the vertical direction Z. The heat transfer tubes 251 are arranged side by side below the heat transfer tube 252. The heat transfer tube 251 extends to the right from the first refrigerant header 60, is folded back downward at the right end, and extends to the left. The heat transfer tube 252 extends to the right from the first refrigerant header 60, is folded back upward at the right end, and extends to the left.

[0085] Two heat transfer tubes 250c, a heat transfer tube 253 and a heat transfer tube 254, are connected to the third space 64c. The heat transfer tubes 253 and 254 are a pair of heat transfer tubes 253, 254 arranged side by side in the vertical direction Z. The pair of heat transfer tubes 253, 254 connected to the third space 64c extend from the first refrigerant header 60 in the left-right direction Y intersecting the vertical direction Z and are folded back in directions away from each other in the vertical direction Z. The heat transfer tube 253 is arranged side by side above the heat transfer tube 252. The heat transfer tube 253 extends to the right from the first refrigerant header 60, is folded back downward at the right end, and extends to the left. The heat transfer tube 254 is arranged side by side above the heat transfer tube 253. The heat transfer tube 254 extends to the right from the first refrigerant header 60, is folded back upward at the right end, and extends to the left.

[0086] The upper heat transfer tube 252 of the pair of heat transfer tubes 251, 252 and the lower heat transfer tube 253 of the pair of heat transfer tubes 253, 254 are arranged side by side in the vertical direction Z. The heat transfer tubes 252 and 253 extend from the first refrigerant header 60 in the left-right direction Y and are folded back in the vertical direction Z so as to approach each other.

[0087] The distance in the vertical direction Z between a pair of heat transfer tubes 251, 252 is the same as the distance in the vertical direction Z between the portions of each heat transfer tube 251, 252 before and after the fold. The distance in the vertical direction Z between a pair of heat transfer tubes 253, 254 is the same as the distance in the vertical direction Z between the portions of each heat transfer tube 253, 254 before and after the fold. The distance in the vertical direction Z between the heat transfer tube 252 and the heat transfer tube 253 is the same as the distance in the vertical direction Z between the portions of each heat transfer tube 252, 253 before and after the fold. Therefore, the portions of the multiple heat transfer tubes 251 to 254 extending in the left-right direction Y are arranged at equal intervals in the vertical direction Z. The ends of the folded portions of each heat transfer tube 251 to 254 are connected to other pipes, such as the above-mentioned connection pipe 55, before returning to the first refrigerant header 60.

[0088] According to the second embodiment, the heat transfer tubes 250b connected to the second space 64b are arranged in a pair side by side in the vertical direction Z. The pair of heat transfer tubes 251, 252 connected to the second space 64b extend from the first refrigerant header 60 in a direction intersecting the vertical direction Z and are bent back in a direction away from each other in the vertical direction Z. The heat transfer tubes 250c connected to the third space 64c are arranged in a pair side by side in the vertical direction Z. The pair of heat transfer tubes 253, 254 connected to the third space 64c extend from the first refrigerant header 60 in a direction intersecting the vertical direction Z and are bent back in a direction away from each other in the vertical direction Z. This makes it easier to lengthen the heat transfer tubes 251 to 254 while arranging the portions of the heat transfer tubes 251 to 254 extending in the left-right direction Y at equal intervals in the vertical direction Z. This makes it easier to send the fluid, i.e., air, that exchanges heat with the refrigerant 19 between the portions of the heat transfer tubes 251 to 254 that extend in the left-right direction Y. This makes it possible to further improve the energy efficiency of the heat exchanger 230.

[0089] Embodiment 3. Fig. 8 is a partial cross-sectional view showing a part of a heat exchanger 330 according to embodiment 3. In the following description, the same components as those in the above-described embodiments may be denoted by the same reference numerals as appropriate, and the description thereof may be omitted.

[0090] As shown in Fig. 8 , in the third embodiment, the second heat exchange section 332 is arranged side by side below the first heat exchange section 331. Similar to the pairs of heat transfer tubes 251, 252 and the pair of heat transfer tubes 253, 254 in the second embodiment, the plurality of heat transfer tubes 340a in the first heat exchange section 331 are grouped into pairs of heat transfer tubes 340a aligned in the vertical direction Z, and the pair of heat transfer tubes 340a in each group extend in the left-right direction Y and are folded back in the vertical direction Z so as to move away from each other. The folded back ends of each heat transfer tube 340a are connected to the second refrigerant header 70. Two pairs of heat transfer tubes 340a are provided for each refrigerant path section 340.

[0091] The pair of heat transfer tubes 351, 352 in the second heat exchange section 332 extend in the same manner as the pair of heat transfer tubes 251, 252 in embodiment 2. The pair of heat transfer tubes 353, 354 in the second heat exchange section 332 extend in the same manner as the pair of heat transfer tubes 253, 254 in embodiment 2. The folded-back ends of the pair of heat transfer tubes 351, 352 and the folded-back ends of the pair of heat transfer tubes 353, 354 are connected to the third refrigerant header 71 of each refrigerant path section 340 via connection pipes 55, respectively.

[0092] In the heat exchanger 330 of the third embodiment, each of the heat transfer tubes 340a, 351-354 is a folded heat transfer tube, and two portions extending in the left-right direction Y are provided with a gap in the vertical direction Z. Furthermore, each of the heat transfer tubes 340a, 351-354 is arranged side by side in the vertical direction Z. This allows the heat exchanger body 330a, including the first heat exchange section 331 and the second heat exchange section 332, to have a structure in which the heat transfer tubes are densely integrated. This allows the heat exchanger 330 to be made compact and the energy efficiency of the heat exchanger 330 to be more suitably improved. The other configurations of the heat exchanger 330 are similar to those of the heat exchanger 30 of the first embodiment.

[0093] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the configurations of the above-described embodiments, and the following configurations and methods may also be adopted.

[0094] The heat transfer tubes connected to the second space and the third space may be any heat transfer tubes as long as they are different from each other. The number of heat transfer tubes connected to the second space and the number of heat transfer tubes connected to the third space are not particularly limited as long as they are at least one each. Three or more heat transfer tubes may be connected to the second space and the third space. The number of heat transfer tubes connected to the second space and the number of heat transfer tubes connected to the third space may be different from each other. The multiple connection holes to which the multiple heat transfer tubes are connected may be formed at equal intervals in the vertical direction. The internal space of the header body of the refrigerant header (first refrigerant header 60) may be divided into four or more vertically arranged spaces by three or more orifice plates, including a first orifice plate and a second orifice plate. Even in this case, the same effects as those of the above-described embodiment can be obtained.

[0095] The heat exchanger according to the present disclosure may be provided in any refrigeration cycle device. The refrigeration cycle device provided with the heat exchanger according to the present disclosure may be any device that utilizes a refrigeration cycle in which a refrigerant circulates, and is not limited to an air conditioner. The refrigeration cycle device may be a refrigerator or a heat pump water heater. When the refrigeration cycle device is an air conditioner, the heat exchanger according to the present disclosure may be applied to the heat exchanger of the outdoor unit, the heat exchanger of the indoor unit, or both the heat exchanger of the indoor unit and the heat exchanger of the outdoor unit.

[0096] The configurations and methods described in this specification can be combined as appropriate within the scope of not contradicting each other.

[0097] 19...refrigerant, 30, 230, 330...heat exchanger, 51, 52, 53, 54, 250b, 250c, 251, 252, 253, 254, 351, 352, 353, 354...heat transfer tube, 56a, 56b, 56c, 56d...connection hole, 60...first refrigerant header (refrigerant header), 61...first orifice plate, 61a...first orifice hole, 62...second orifice plate, 62a...second orifice hole, 63...header body, 64a...first space, 64b...second space, 64c...third space, 81, 82...refrigerant piping, 100...refrigeration cycle device, G1, G3...spacing (first spacing), G2...spacing (second spacing), Y...left-right direction (intersecting direction), Z...vertical direction

Claims

1. A heat exchanger for a refrigeration cycle device, comprising: a plurality of heat transfer tubes; and a refrigerant header to which a refrigerant pipe and the plurality of heat transfer tubes are connected, and which can distribute refrigerant flowing in from the refrigerant pipe to the plurality of heat transfer tubes, wherein the refrigerant header has: a cylindrical header main body portion extending in the vertical direction; a first orifice plate located inside the header main body portion and having a first orifice hole formed therein; and a second orifice plate located inside the header main body portion and having a second orifice hole formed therein, wherein the internal space of the header main body portion is partitioned by the first orifice plate and the second orifice plate into a first space, a second space, and a third space, wherein the first space and the second space are connected to each other via the first orifice hole, and the second space and the third space are connected to each other via the second orifice hole, wherein the second space is located vertically above the first space, and the third space is located vertically above the second space, the refrigerant pipe is connected to the first space; and different heat transfer tubes from the plurality of heat transfer tubes are connected to the second space and the third space.

2. A heat exchanger as described in claim 1, wherein the header body is formed with a plurality of connection holes to which the plurality of heat transfer tubes are respectively connected, the plurality of connection holes are arranged at intervals in the vertical direction, the vertical intervals between the plurality of connection holes include a first interval and a second interval larger than the first interval, and the second orifice plate is located between the connection holes arranged at the second interval in the vertical direction.

3. A heat exchanger as described in claim 1 or 2, wherein the heat transfer tubes connected to the second space are arranged in a pair side by side in the vertical direction, the pair of heat transfer tubes connected to the second space extend from the refrigerant header in a direction intersecting the vertical direction and are bent back in a direction away from each other in the vertical direction, and the heat transfer tubes connected to the third space are arranged in a pair side by side in the vertical direction, and the pair of heat transfer tubes connected to the third space extend from the refrigerant header in a direction intersecting the vertical direction and are bent back in a direction away from each other in the vertical direction.

4. A heat exchanger as described in any one of claims 1 to 3, wherein the plurality of heat transfer tubes are connected to the header main body from a first side in a cross direction that crosses the vertical direction, the first orifice hole is formed in a portion of the first orifice plate that is located on a second side opposite to the first side from the center of the cross direction, and the second orifice hole is formed in a portion of the second orifice plate that is located on the second side from the center of the cross direction.

5. A heat exchanger according to any one of claims 1 to 4, wherein one ends of the plurality of heat transfer tubes are inserted into the header main body, and when the portion of the heat transfer tubes connected to the second space that is located within the second space is projected vertically onto the first orifice plate, the first orifice hole is formed in a region of the first orifice plate different from the region onto which the portion of the heat transfer tube is projected, and when the portion of the heat transfer tubes connected to the third space that is located within the third space is projected vertically onto the second orifice plate, the second orifice hole is formed in a region of the second orifice plate different from the region onto which the portion of the heat transfer tube is projected.

6. A heat exchanger according to claim 5, wherein the plurality of heat transfer tubes are flat tubes whose vertical dimension is smaller than their dimensions in a direction perpendicular to both the direction in which the heat transfer tubes extend and the vertical direction.

7. A heat exchanger according to any one of claims 1 to 6, wherein the cross-sectional area of ​​the first orifice hole and the cross-sectional area of ​​the second orifice hole are smaller than the flow path cross-sectional area of ​​the refrigerant pipe.

8. A refrigeration cycle device comprising a heat exchanger according to any one of claims 1 to 7.

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