Refrigeration cycle equipment

Abstract

The refrigeration cycle device includes a primary distributor that performs primary distribution of a refrigerant, a heat exchanger into which the refrigerant primarily distributed by the primary distributor flows, and a plurality of connecting pipes that connect the primary distributor and the heat exchanger. The heat exchanger has a plurality of heat transfer tubes extending in the vertical direction, and a secondary distributor connected to the lower ends of the plurality of heat transfer tubes and that secondarily distributes the refrigerant primarily distributed by the primary distributor to the plurality of heat transfer tubes. The secondary distributor has a plurality of distribution chambers, and each of the plurality of distribution chambers is connected to one connecting pipe of the plurality of connecting pipes and n heat transfer tubes of the plurality of heat transfer tubes, where n is an integer of 2 or more, and the sum of the flow path cross-sectional areas of the n heat transfer tubes is 10 times or less the flow path cross-sectional area of ​​one connecting pipe.

Description

[Technical Field]

[0001] The present disclosure relates to a refrigeration cycle device equipped with a heat exchanger. [Background technology]

[0002] Patent Document 1 discloses a heat exchanger. The heat exchanger includes a plurality of heat transfer tubes and a cylindrical refrigerant distributor formed at intervals in a first direction and having insertion holes into which the ends of the heat transfer tubes are inserted from a second direction. The refrigerant distributor includes a first partition plate and an inlet pipe. The first partition plate divides the interior of the refrigerant distributor into a first space on the side into which the ends of the heat transfer tubes are inserted and a second space on the side into which the ends of the heat transfer tubes are not inserted, the second space having a larger volume than the first space. The inlet pipe is provided on one side of the refrigerant distributor and allows a gas-liquid two-phase refrigerant to flow into the second space. The heat transfer tubes are inserted into the insertion holes so that their ends are spaced apart from the first partition plate in the first space. The first partition plate is provided with orifices corresponding to each space between adjacent heat transfer tubes, connecting the first space with the second space. This structure allows the refrigerant flow path to be divided into the first space and the second space, reducing fluid resistance at the connection between the heat transfer tube and the refrigerant distributor and enabling the refrigerant distributor to have a smaller capacity. Furthermore, the first space is connected in the first direction, and the gas-liquid two-phase refrigerant sprayed from the orifice mixes in the space formed by the adjacent heat transfer tubes, improving refrigerant distribution characteristics and heat exchanger performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 161761 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above heat exchanger, since all the heat transfer tubes are connected to the first space of the refrigerant distributor, there was a problem that if the number of heat transfer tubes increases, the refrigerant distribution deviation may become large.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a refrigeration cycle device that can reduce deviation in refrigerant distribution to a plurality of heat transfer tubes. [Means for solving the problem]

[0006] A refrigeration cycle device according to the present disclosure includes a primary distributor that primarily distributes a refrigerant, a heat exchanger into which the refrigerant primarily distributed by the primary distributor flows, and a plurality of connecting pipes that connect the primary distributor and the heat exchanger, wherein the heat exchanger has a plurality of heat transfer tubes extending in a vertical direction, and a secondary distributor that is connected to lower ends of the plurality of heat transfer tubes and secondarily distributes the refrigerant primarily distributed by the primary distributor to the plurality of heat transfer tubes, and the secondary distributor has a plurality of distribution chambers, and one connecting pipe of the plurality of connecting pipes and n heat transfer tubes of the plurality of heat transfer tubes are connected to each of the plurality of distribution chambers, n is an integer of 2 or more, and the sum of the flow path cross-sectional areas of the n heat transfer tubes is 10 times or less the flow path cross-sectional area of ​​the one connecting pipe. the secondary distributor has a configuration in which a plurality of plate-like members are stacked, the secondary distributor is provided with connection pipe holes corresponding to each of the plurality of distribution chambers, and the connection pipes are connected to the connection pipes; the secondary distributor is formed with refrigerant diffusion spaces provided between the connection pipe holes and each of the plurality of distribution chambers in the refrigerant flow; the refrigerant diffusion spaces include a first refrigerant diffusion space and a second refrigerant diffusion space provided between the first refrigerant diffusion space and each of the plurality of distribution chambers in the refrigerant flow; when viewed parallel to the extending direction of the plurality of heat transfer tubes, the first refrigerant diffusion space extends on both sides from the connecting pipe holes along a first direction, and the second refrigerant diffusion space extends on both sides from ends of the first refrigerant diffusion space along a second direction intersecting the first direction. . [Effects of the Invention]

[0007] According to the present disclosure, deviation in refrigerant distribution to a plurality of heat transfer tubes can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a refrigerant circuit diagram showing a schematic configuration of a refrigeration cycle device according to a first embodiment. [Figure 2] 2 is a diagram showing the configuration of a primary distributor and a heat exchanger of the refrigeration cycle device according to the first embodiment. FIG. [Figure 3] 2 is an exploded view showing the configuration of a secondary distributor in the refrigeration cycle device according to the first embodiment. FIG. [Figure 4] 3 is a top view showing the configuration of a secondary distributor in the refrigeration cycle apparatus according to the first embodiment. FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the VV cross section of FIG. [Figure 6] FIG. 10 is an exploded view showing the configuration of a secondary distributor in a refrigeration cycle apparatus according to a second embodiment. [Figure 7] FIG. 10 is a top view showing the configuration of a secondary distributor in a refrigeration cycle apparatus according to a second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the VIII-VIII cross section of FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view showing a cross section taken along line IX-IX in FIG. 7. [Figure 10] FIG. 10 is a schematic diagram showing the configuration of a primary distributor and a heat exchanger of a refrigeration cycle device according to a third embodiment. [Figure 11] FIG. 10 is a bottom view showing the configuration of a heat exchanger of a refrigeration cycle device according to a third embodiment. [Figure 12] FIG. 10 is a top view showing the configuration of a heat exchanger of a refrigeration cycle device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the following embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure. Furthermore, the present disclosure includes all possible combinations of the configurations shown in the following embodiments. In particular, the combinations of components are not limited to those in the respective embodiments; components described in one embodiment can be applied to another embodiment. In the following description, directional terms (e.g., "up," "down," "right," "left," "front," "rear," etc.) may be used as appropriate to facilitate understanding. However, these terms are for explanatory purposes and do not limit the present disclosure. In the drawings, components designated with the same reference numerals are identical or equivalent, and this applies throughout the entire specification. The relative dimensional relationships or shapes of the components in the drawings may differ from those in actuality.

[0010] Embodiment 1 A refrigeration cycle apparatus according to a first embodiment will be described. Fig. 1 is a refrigerant circuit diagram showing a schematic configuration of the refrigeration cycle apparatus according to the present embodiment. As shown in Fig. 1, the refrigeration cycle apparatus includes a compressor 110, a heat exchanger 120 functioning as a condenser, an expansion device 130, a primary distributor 140, a plurality of connection pipes 141a to 141d, and a heat exchanger 150 functioning as an evaporator. The compressor 110, the heat exchanger 120, the expansion device 130, the primary distributor 140, and the heat exchanger 150 are connected in a ring shape to form a refrigerant circuit.

[0011] The heat exchanger 120 is, for example, an indoor heat exchanger disposed indoors. The heat exchanger 150 is, for example, an outdoor heat exchanger disposed outdoors. The primary distributor 140 is provided separately from the heat exchanger 150. The primary distributor 140 and the heat exchanger 150 are connected by a plurality of connection pipes 141a to 141d. In this embodiment, the number of connection pipes 141a to 141d is four.

[0012] The compressor 110 draws in, compresses, and discharges low-pressure gas refrigerant. The high-pressure gas refrigerant discharged from the compressor 110 flows into the heat exchanger 120. The gas refrigerant that flows into the heat exchanger 120 condenses, for example, through heat exchange with indoor air, and becomes high-pressure liquid refrigerant. The liquid refrigerant that flows out of the heat exchanger 120 is decompressed by the expansion device 130 and becomes low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is primarily distributed by the primary distributor 140 and flows into the heat exchanger 150 through multiple connection pipes 141a to 141d. The refrigerant that flows into the heat exchanger 150 is secondarily distributed by a secondary distributor, which will be described later, and distributed to multiple heat transfer tubes. The gas-liquid two-phase refrigerant that flows into the heat exchanger 150 evaporates, for example, through heat exchange with outdoor air, and becomes low-pressure gas refrigerant. The low-pressure gas refrigerant is then drawn into the compressor 110.

[0013] The refrigeration cycle device may be provided with a four-way valve that switches the refrigerant flow between heating operation and cooling operation. In this case, during heating operation, the heat exchanger 120 functions as a condenser, and the heat exchanger 150 functions as an evaporator. During cooling operation, the heat exchanger 120 functions as an evaporator, and the heat exchanger 150 functions as a condenser.

[0014] Fig. 2 is a diagram showing the configuration of a primary distributor and a heat exchanger of a refrigeration cycle apparatus according to this embodiment. The up-down direction in Fig. 2 represents the vertical direction. Here, in this embodiment, the primary distributor 140 and the heat exchanger 150 shown in Fig. 1 are exemplified as the primary distributor and the heat exchanger, but are not limited thereto. When a four-way valve is provided in the refrigeration cycle apparatus, the primary distributor and the heat exchanger shown in Fig. 2 may be used instead of the heat exchanger 120 shown in Fig. 1.

[0015] 2, the heat exchanger 150 includes a plurality of heat transfer tubes 10, a plurality of heat transfer fins 11, a secondary distributor 20, and a gas header 12. The heat exchanger 150 functions as an evaporator in at least some operation modes.

[0016] The heat transfer tubes 10 are arranged in parallel in the horizontal direction. Each heat transfer tube 10 extends in an up-down direction, for example, in the vertical up-down direction. In this embodiment, flat tubes having a flat cross-sectional shape are used as the heat transfer tubes 10. Each heat transfer tube 10 is arranged so that the major axis direction in the cross section is along the air flow direction. Each heat transfer fin 11 is provided between two adjacent heat transfer tubes 10. Each heat transfer fin 11 is formed in a corrugated shape.

[0017] The gas header 12 is connected to the upper ends of the heat transfer tubes 10. The gas header 12 has, for example, a cylindrical shape. The gas header 12 is located on the outlet side of the heat exchanger 150 in the flow of the refrigerant when the heat exchanger 150 functions as an evaporator.

[0018] The secondary distributor 20 is connected to the lower ends of the plurality of heat transfer tubes 10. The secondary distributor 20 is located on the inlet side of the heat exchanger 150 in the refrigerant flow when the heat exchanger 150 functions as an evaporator. The secondary distributor 20 has a plurality of distribution chambers 32a, 32b, 32c, and 32d formed therein. The configuration of the secondary distributor 20 will be described in detail later.

[0019] The primary distributor 140 is a functional component that distributes the refrigerant. The primary distributor 140 is provided separately from the heat exchanger 150. The primary distributor 140 is a distributor-type refrigerant distributor. The primary distributor 140 homogenizes the gas-liquid two-phase refrigerant flowing in from below in an internal gas-liquid mixing chamber, branches the homogenized refrigerant into multiple branch flow paths, and uniformly discharges the refrigerant from multiple outlets radially arranged above. One end of each of the connecting pipes 141a, 141b, 141c, and 141d is connected to each outlet of the primary distributor 140. The primary distributor 140 is connected to the secondary distributor 20 via multiple connecting pipes 141a, 141b, 141c, and 141d. The number of connecting pipes 141a, 141b, 141c, and 141d is the same as the number of distribution chambers 32a, 32b, 32c, and 32d of the secondary distributor 20. The other ends of the connecting pipes 141a, 141b, 141c, and 141d are connected to the corresponding distribution chambers 32a, 32b, 32c, and 32d. As a result, the refrigerant is primarily distributed to the distribution chambers 32a to 32d of the secondary distributor 20 by the primary distributor 140. The distribution ratio of the refrigerant to each distribution chamber 32a to 32d can be easily adjusted by adjusting the length of each connecting pipe 141a to 141d. This is because the frictional pressure loss of each connecting pipe 141a to 141d is the dominant factor determining the distribution ratio of the refrigerant to each distribution chamber 32a to 32d.

[0020] Fig. 3 is an exploded view showing the configuration of a secondary distributor in a refrigeration cycle apparatus according to this embodiment. Fig. 3 shows a planar configuration of each plate-like member 21, 22, 23, 24 of secondary distributor 20 viewed along the plate thickness direction, i.e., the extension direction of heat transfer tubes 10. Fig. 4 is a top view showing the configuration of a secondary distributor in a refrigeration cycle apparatus according to this embodiment. Fig. 4 shows the configuration of secondary distributor 20, in which plate-like members 21, 22, 23, 24 are stacked, viewed from above along the plate thickness direction. Fig. 5 is a cross-sectional view showing a VV cross section of Fig. 4. The up-down direction in Fig. 5 represents the vertical up-down direction. The left-right direction in each of Figs. 3 to 5 represents the parallel arrangement direction of heat transfer tubes 10.

[0021] As shown in FIGS. 3 to 5, the secondary distributor 20 is a stacked horizontal distributor having a configuration in which four plate-shaped members 21, 22, 23, and 24 are stacked. The plate-shaped members 21, 22, 23, and 24 are integrally brazed together with the connection pipes 141a to 141d, the heat transfer tubes 10, and the gas header 12. The plate-shaped members 21, 22, 23, and 24 are stacked in this order from above, i.e., from the gas header 12 side. Each of the plate-shaped members 21, 22, 23, and 24 is formed into a rectangular shape whose length is in the direction in which the heat transfer tubes 10 are arranged side by side. The outline shape of the outer edge of each of the plate-shaped members 21, 22, 23, and 24 is, for example, the same. The plate thicknesses of the plate-shaped members 21, 22, 23, and 24 may be different from one another. The plate-shaped members 21, 22, 23, and 24 are arranged so that their plate surfaces are perpendicular to the extension direction of the heat transfer tubes 10.

[0022] A plurality of slits 31 into which the lower ends of the heat transfer tubes 10 are inserted are formed in the plate-like member 21. Each slit 31 penetrates the plate-like member 21 in the plate thickness direction. In this embodiment, flat tubes are used as the heat transfer tubes 10, and therefore each slit 31 is formed in a flat shape corresponding to the cross-sectional shape of each heat transfer tube 10.

[0023] Four openings 32a1, 32b1, 32c1, and 32d1 are formed in the plate-like member 22. Each of the openings 32a1, 32b1, 32c1, and 32d1 penetrates the plate-like member 22 in the plate thickness direction. When viewed in the plate thickness direction, each of the openings 32a1, 32b1, 32c1, and 32d1 has a rectangular shape. The openings 32a1, 32b1, 32c1, and 32d1 are arranged in parallel in the parallel arrangement direction of the heat transfer tubes 10. When viewed in the plate thickness direction, each of the openings 32a1 to 32d1 overlaps with a plurality of slits 31. In this embodiment, the number of slits 31 overlapping with the opening 32d1 is smaller than the number of slits 31 overlapping with each of the openings 32a1, 32b1, and 32c1. The openings 32a1 to 32d1 are configured to form distribution chambers 32a to 32d, respectively, when the plate-like members 21, 22, 23, and 24 are stacked.

[0024] Four refrigerant inlet holes 33a, 33b, 33c, and 33d are formed in the plate-shaped member 23. Each of the refrigerant inlet holes 33a, 33b, 33c, and 33d penetrates the plate-shaped member 23 in the plate thickness direction. When viewed in the plate thickness direction, each of the refrigerant inlet holes 33a, 33b, 33c, and 33d has a circular shape. The refrigerant inlet holes 33a, 33b, 33c, and 33d are aligned in the direction in which the heat transfer tubes 10 are aligned. When viewed in the plate thickness direction, the refrigerant inlet holes 33a, 33b, 33c, and 33d overlap with the openings 32a1, 32b1, 32c1, and 32d1, respectively.

[0025] Four connection pipe holes 34a, 34b, 34c, and 34d are formed in the plate-shaped member 24. Each of the connection pipe holes 34a, 34b, 34c, and 34d penetrates the plate-shaped member 24 in the plate thickness direction. When viewed in the plate thickness direction, each of the connection pipe holes 34a, 34b, 34c, and 34d has a circular shape. The diameter of each of the connection pipe holes 34a, 34b, 34c, and 34d is larger than the diameter of each of the refrigerant inlet holes 33a, 33b, 33c, and 33d. When viewed in the plate thickness direction, the connection pipe holes 34a, 34b, 34c, and 34d overlap with the refrigerant inlet holes 33a, 33b, 33c, and 33d, respectively.

[0026] Corresponding connection pipes 141a, 141b, 141c, and 141d are inserted into connection pipe holes 34a, 34b, 34c, and 34d. The outer diameter of each connection pipe 141a, 141b, 141c, and 141d is smaller than the diameter of each connection pipe hole 34a, 34b, 34c, and 34d, but larger than the diameter of each refrigerant inlet hole 33a, 33b, 33c, and 33d. The tip of each connection pipe 141a, 141b, 141c, and 141d abuts against the plate-like member 23 around each refrigerant inlet hole 33a, 33b, 33c, and 33d.

[0027] The following description will focus on the structure of the distribution chamber 32a and its periphery, but the structures of the other distribution chambers 32b to 32d and their peripheries are similar. As shown in Fig. 5, the lower ends of multiple heat transfer tubes 10 are connected to the distribution chamber 32a. The upper limit of the number of heat transfer tubes 10 that can be connected to one distribution chamber is approximately 10. Multiple slits 31 into which the heat transfer tubes 10 are inserted are provided above the distribution chamber 32a.

[0028] The refrigerant inlet hole 33a and the connecting pipe hole 34a are provided below the distribution chamber 32a. Therefore, the connecting pipe 141a is connected to the distribution chamber 32a from below the secondary distributor 20 upward. The refrigerant flows from the connecting pipe 141a through the refrigerant inlet hole 33a into the distribution chamber 32a. The central axis 33a1 of the refrigerant inlet hole 33a extends, for example, vertically. The central axis 33a1 passes through the center between two adjacent slits 31 in the parallel arrangement direction of the heat transfer tubes 10.

[0029] A collision wall 40 is provided above the distribution chamber 32a. The collision wall 40 is disposed opposite the refrigerant inlet hole 33a and is located on the central axis 33a1 of the refrigerant inlet hole 33a. The collision wall 40 is formed on the lower surface of the plate-like member 21 between two adjacent slits 31, i.e., between two adjacent heat transfer tubes 10.

[0030] The distance from the refrigerant inlet hole 33a to the collision wall 40 is shorter than the distance from the refrigerant inlet hole 33a to the heat transfer tube 10 closest to the refrigerant inlet hole 33a. The refrigerant that flows into the distribution chamber 32a from the refrigerant inlet hole 33a first collides with the collision wall 40 and then diffuses within the distribution chamber 32a. This prevents the refrigerant that flows into the distribution chamber 32a from flowing directly into the heat transfer tube 10.

[0031] The refrigerant inlet hole 33a and the collision wall 40 are located substantially in the center of the opening 32a1 in the parallel arrangement direction of the heat transfer tubes 10. When an even number of heat transfer tubes 10 are connected to the distribution chamber 32a, the refrigerant inlet hole 33a and the collision wall 40 can be located exactly in the center of the opening 32a1 in the parallel arrangement direction of the heat transfer tubes 10. On the other hand, when an odd number of heat transfer tubes 10 are connected to the distribution chamber 32a, the heat transfer tube 10 (the third heat transfer tube 10 from the left in FIG. 5) is located in the center of the opening 32a1 in the parallel arrangement direction of the heat transfer tubes 10. In this case, the refrigerant inlet hole 33a and the collision wall 40 are located on the underside of the plate-shaped member 21, between the heat transfer tube 10 located in the center of the opening 32a1 in the parallel arrangement direction of the heat transfer tubes 10 and the heat transfer tube 10 adjacent to that heat transfer tube 10. Although this position is not exactly the center position of the opening 32a1 in the direction in which the heat transfer tubes 10 are arranged side by side, it is substantially the center of the opening 32a1.

[0032] In the configuration of the primary distributor 140 and the heat exchanger 150 as described above, the gas-liquid two-phase refrigerant that flows into the primary distributor 140 from the expansion device 130 side is primarily distributed to the distribution chambers 32a-32d. In this primary distribution, the refrigerant can be distributed to the distribution chambers 32a-32d at an appropriate distribution ratio by adjusting the pressure loss of each of the connecting pipes 141a-141d. Even if the sizes of the distribution chambers 32a-32d are different or the numbers of heat transfer tubes 10 connected to the distribution chambers 32a-32d are different, the refrigerant can be appropriately distributed by adjusting the pressure loss of each of the connecting pipes 141a-141d.

[0033] The gas-liquid two-phase refrigerant that flows into the distribution chamber 32a from the connection pipe 141a collides with the collision wall 40 and flows through the distribution chamber 32a to both sides of the heat transfer tubes 10 in the parallel direction. Then, the gas-liquid two-phase refrigerant passes through each slit 31 and is secondarily distributed to each of the heat transfer tubes 10 connected to the distribution chamber 32a. The gas-liquid two-phase refrigerant that flows into the other distribution chambers 32b to 32d is similarly distributed to each of the heat transfer tubes 10. This secondary distribution allows the number of heat transfer tubes 10 to which the refrigerant is distributed from each of the distribution chambers 32a to 32d to be smaller than the total number of heat transfer tubes 10 in the heat exchanger 150, thereby reducing the deviation in the distribution of the refrigerant from each of the distribution chambers 32a to 32d to the heat transfer tubes 10. Therefore, by combining the primary and secondary distributions described above, the deviation in the distribution of the refrigerant to all of the heat transfer tubes 10 can be reduced.

[0034] The gas-liquid two-phase refrigerant flowing upward inside each heat transfer tube 10 is heated and evaporated by heat exchange with the air, becoming a gas refrigerant that joins the two flows in the gas header 12. The gas refrigerant then flows out of the heat exchanger 150 and is drawn into the compressor 110.

[0035] Here, the cross-sectional area of ​​the flow path of the connecting pipe 141a is Aref [m 2 ]. The inflow mass flow rate of the refrigerant flowing through the connection pipe 141a is Mref [kg / s]. The inflow mass flux of the refrigerant flowing through the connection pipe 141a is Gref [kg / (m 2 ·s)] (Gref=Mref / Aref). Mass flux is the mass flow rate per unit cross-sectional area. The number of heat transfer tubes 10 per connecting pipe, that is, the number of heat transfer tubes 10 connected to the distribution chamber 32a, is assumed to be n. The flow path cross-sectional area of ​​one heat transfer tube 10 is assumed to be Aft [m 2 ]. The mass flow rate of the refrigerant flowing through one heat transfer tube 10 is Mft [kg / s] (Mft = Mref / n). The mass flux of the refrigerant flowing through one heat transfer tube 10 is Gft [kg / (m 2 ·s)] (Gft=Mft / Aft).

[0036] In the configuration of this embodiment, the sum of the flow path cross-sectional areas Aft of the n heat transfer tubes 10 is 10 times or less the flow path cross-sectional area Aref of one connecting pipe 141a (n·Aft≦10·Aref). Also, in the configuration of this embodiment, the mass flux Gft of the refrigerant flowing through each of the n heat transfer tubes 10 is 10 times or less the mass flux Gref of the refrigerant flowing through one connecting pipe 141a (Gft≦10·Gref).

[0037] Generally, the number of branches of the refrigerant flow path in the heat exchanger of a refrigeration cycle device is determined so that the mass flux Gft per heat transfer tube is within an appropriate range, since if the number is too small, the pressure loss in the heat transfer tube becomes excessive, and if the number is too large, the heat transfer between the refrigerant and the heat transfer tube is hindered.

[0038] On the other hand, if the rate of decrease in mass flux before and after branching exceeds 10, the refrigerant distribution characteristics deteriorate. Therefore, in this embodiment, the refrigerant is distributed by the primary distributor 140 and the mass flux Gref is adjusted so that the mass flux Gref of the refrigerant in the connecting pipe 141a is 10 times or less the mass flux Gft in the heat transfer tube.

[0039] As a result, in this embodiment, the relationship Gft≦10 Gref is satisfied. That is, in the configuration of this embodiment, the mass flux Gft of the refrigerant flowing through each of the n heat transfer tubes 10 is 10 times or less the mass flux Gref of the refrigerant flowing through one connecting pipe 141a. By satisfying this relationship, it is possible to further reduce the deviation in the distribution of the refrigerant to the multiple heat transfer tubes 10.

[0040] Furthermore, by rearranging the relational expression Gft≦10·Gref using the relationships Gref=Mref / Aref, Mft=Mref / n, and Gft=Mft / Aft, the relationship n·Aft≦10·Aref is obtained. That is, in the configuration of this embodiment, the sum of the flow path cross-sectional areas Aft of the n heat transfer tubes 10 is 10 times or less the flow path cross-sectional area Aref of one connecting pipe 141a. By satisfying this relationship, it is possible to further reduce the deviation in refrigerant distribution to the multiple heat transfer tubes 10.

[0041] As described above, the refrigeration cycle apparatus according to this embodiment includes the primary distributor 140, the heat exchanger 150, and a plurality of connection pipes 141a-141d that connect the primary distributor 140 and the heat exchanger 150. The primary distributor 140 is configured to perform primary distribution of the refrigerant. The refrigerant that has been primarily distributed by the primary distributor 140 flows into the heat exchanger 150. The plurality of connection pipes 141a-141d connect the primary distributor 140 and the heat exchanger 150.

[0042] The heat exchanger 150 has a plurality of heat transfer tubes 10 and a secondary distributor 20. The plurality of heat transfer tubes 10 extend in the vertical direction. The secondary distributor 20 is connected to the lower ends of the plurality of heat transfer tubes 10. The secondary distributor 20 is configured to secondarily distribute the refrigerant primarily distributed by the primary distributor 140 to the plurality of heat transfer tubes 10. The secondary distributor 20 has a plurality of distribution chambers 32a-32d formed therein. One of the plurality of connection pipes 141a-141d and n of the plurality of heat transfer tubes 10 are connected to each of the plurality of distribution chambers 32a-32d, where n is an integer of 2 or more. The sum of the flow path cross-sectional areas Aft of the n heat transfer tubes 10 is 10 times or less the flow path cross-sectional area Aref of the one connection pipe.

[0043] With this configuration, the primary distributor 140 can distribute the refrigerant to the distribution chambers 32a-32d at an appropriate distribution ratio by adjusting the pressure loss of each of the connecting pipes 141a-141d. Furthermore, in the secondary distributor 20, the number of heat transfer tubes 10 to which the refrigerant is distributed from each of the distribution chambers 32a-32d can be kept smaller than the total number of heat transfer tubes 10 in the heat exchanger 150, thereby reducing the distribution deviation of the refrigerant from each of the distribution chambers 32a-32d to the heat transfer tubes 10. Furthermore, the sum of the flow path cross-sectional areas Aft of the n heat transfer tubes 10 is 10 times or less the flow path cross-sectional area Aref of the single connecting pipe, thereby further reducing the distribution deviation of the refrigerant to the plurality of heat transfer tubes 10.

[0044] In the refrigeration cycle apparatus according to this embodiment, the mass flux Gft of the refrigerant flowing through each of the n heat transfer tubes 10 is 10 times or less the mass flux of the refrigerant flowing through the one connecting pipe.

[0045] According to this configuration, the deviation in distribution of the refrigerant to the plurality of heat transfer tubes 10 can be further reduced.

[0046] In the refrigeration cycle apparatus according to this embodiment, each of the plurality of distribution chambers 32a to 32d is provided with a refrigerant inlet hole through which the refrigerant flows from the single connecting pipe, and a collision wall that is arranged opposite the refrigerant inlet hole and against which the refrigerant flowing in from the refrigerant inlet hole collides. For example, distribution chamber 32a is provided with refrigerant inlet hole 33a through which the refrigerant flows from connecting pipe 141a, and a collision wall 40 that is arranged opposite refrigerant inlet hole 33a and against which the refrigerant flowing in from refrigerant inlet hole 33a collides.

[0047] If the refrigerant that has flowed into the distribution chamber 32a through the refrigerant inlet hole 33a flows directly into some of the heat transfer tubes 10, the flow rate of the refrigerant distributed to those heat transfer tubes 10 will be relatively high. According to the above configuration, the refrigerant that has flowed into the distribution chamber 32a through the refrigerant inlet hole 33a collides with the collision wall 40, which prevents the refrigerant that has flowed into the distribution chamber 32a from flowing directly into some of the heat transfer tubes 10, thereby further reducing the refrigerant distribution deviation.

[0048] In the refrigeration cycle apparatus according to this embodiment, the refrigerant inlet holes 33a to 33d are provided in the center of each of the distribution chambers 32a to 32d in the direction in which the heat transfer tubes 10 are arranged side by side.

[0049] With this configuration, in the parallel arrangement direction of the heat transfer tubes 10, the number of heat transfer tubes 10 located on one side of the refrigerant inlet holes 33a-33d and the collision wall 40 can be made closer to the number of heat transfer tubes 10 located on the other side of the refrigerant inlet holes 33a-33d and the collision wall 40. This makes it possible to further reduce the refrigerant distribution deviation.

[0050] In the refrigeration cycle apparatus according to this embodiment, the refrigerant inlet holes 33a to 33d are provided below the plurality of distribution chambers 32a to 32d, respectively.

[0051] According to this configuration, the connection pipes 141a to 141d can be connected to the distribution chambers 32a to 32d from below the secondary distributor 20, thereby preventing positional interference between the connection pipes 141a to 141d and the plurality of heat transfer tubes 10.

[0052] In the refrigeration cycle apparatus according to this embodiment, the secondary distributor 20 has a configuration in which a plurality of plate-like members 21, 22, 23, and 24 are stacked.

[0053] This configuration reduces the number of parts in secondary distributor 20, enabling cost reduction. In addition, secondary distributor 20 can be made thinner due to the laminated structure of multiple plate-like members 21, 22, 23, and 24, making it possible to reduce the refrigerant volume within secondary distributor 20. In this embodiment, by using a primary distributor 140 that can achieve low distribution deviation in combination with a laminated secondary distributor 20 that has a reduced number of branches per distribution chamber, it is possible to achieve both a reduction in refrigerant distribution deviation and a reduction in refrigerant volume.

[0054] Embodiment 2 A refrigeration cycle apparatus according to a second embodiment will be described. FIG. 6 is an exploded view showing the configuration of a secondary distributor in the refrigeration cycle apparatus according to this embodiment. FIG. 6 shows a plan view of the plate-like members 21, 22, 25, 26, and 24 of the secondary distributor 20, viewed in the thickness direction, i.e., along the extension direction of the heat transfer tubes 10. FIG. 7 is a top view showing the configuration of the secondary distributor in the refrigeration cycle apparatus according to this embodiment. FIG. 7 shows the configuration of the secondary distributor 20, in which the plate-like members 21, 22, 25, 26, and 24 are stacked, viewed from above in the thickness direction. FIG. 8 is a cross-sectional view showing the VIII-VIII cross section of FIG. 7. FIG. 9 is a cross-sectional view showing the IX-IX cross section of FIG. 7. The up-down direction in FIGS. 8 and 9 represents the vertical up-down direction. The left-right direction in FIGS. 6, 7, and 9 represents the parallel arrangement direction of the heat transfer tubes 10. The up-down direction in FIGS. 6 and 7 and the left-right direction in FIG. 8 represent the major axis direction in the cross section of the heat transfer tube 10. The configuration of the heat exchanger 150 other than the secondary distributor 20 and the refrigeration cycle device is the same as that of the first embodiment.

[0055] As shown in FIGS. 6 to 9, the secondary distributor 20 is a stacked horizontal distributor having a configuration in which five plate-like members 21, 22, 25, 26, and 24 are stacked. The plate-like members 21, 22, 25, 26, and 24 are integrated by brazing together with the connection pipes 141a to 141d, the plurality of heat transfer tubes 10, and the gas header 12. The plate-like members 21, 22, 25, 26, and 24 are stacked in this order from above, i.e., from the gas header 12 side. Each of the plate-like members 21, 22, 25, 26, and 24 is formed in a rectangular shape that is elongated in the direction in which the heat transfer tubes 10 are arranged side by side. The outline shape of the outer edge of each of the plate-like members 21, 22, 25, 26, and 24 is, for example, the same. The plate-like members 21, 22, 25, 26, and 24 may have different plate thicknesses. The plate-like members 21, 22, 25, 26, and 24 are arranged so that the plate surfaces thereof are perpendicular to the extending direction of the heat transfer tube 10.

[0056] The plate-like members 21, 22, and 24 have the same configuration as the plate-like members 21, 22, and 24 of the first embodiment.

[0057] Four refrigerant diffusion slits 35a and four refrigerant diffusion slits 35b are formed in the plate-shaped member 25. Each refrigerant diffusion slit 35a and each refrigerant diffusion slit 35b penetrates the plate-shaped member 25 in the plate thickness direction and extends in the parallel direction of the heat transfer tubes 10. One refrigerant diffusion slit 35a and one refrigerant diffusion slit 35b are formed corresponding to each of the distribution chambers 32a, 32b, 32c, and 32d. An impingement wall 40 is formed on the lower surface of the plate-shaped member 25 between the refrigerant diffusion slits 35a and the refrigerant diffusion slits 35b.

[0058] Four refrigerant diffusion slits 36 are formed in the plate-shaped member 26. Each refrigerant diffusion slit 36 ​​penetrates the plate-shaped member 26 in the thickness direction and extends in the major axis direction of the heat transfer tube 10. One refrigerant diffusion slit 36 ​​is formed corresponding to each of the distribution chambers 32a, 32b, 32c, and 32d. The width of the refrigerant diffusion slit 36 ​​in the parallel arrangement direction of the heat transfer tubes 10 is smaller than the diameter of the connecting pipes 141a, 141b, 141c, and 141d.

[0059] Four connection pipe holes 34a, 34b, 34c, and 34d are formed in the plate-like member 24. When viewed in the plate thickness direction, each of the connection pipe holes 34a, 34b, 34c, and 34d has a circular shape. The diameter of each of the connection pipe holes 34a, 34b, 34c, and 34d is larger than the diameter of each of the connection pipes 141a, 141b, 141c, and 141d.

[0060] The refrigerant diffusion slits 36 of the plate-like member 26 form first refrigerant diffusion spaces 37. When viewed in the plate thickness direction, the first refrigerant diffusion spaces 37 overlap with each of the connecting pipe holes 34a to 34d. When viewed in the plate thickness direction, the first refrigerant diffusion spaces 37 extend from each of the connecting pipe holes 34a to 34d to both sides along the major axis direction of the heat transfer tube 10. The first refrigerant diffusion spaces 37 are configured to diffuse the refrigerant that flows in from each of the connecting pipes 141a to 141d along the major axis direction of the heat transfer tube 10.

[0061] The refrigerant diffusion slit 35a of the plate-shaped member 25 forms a second refrigerant diffusion space 38a. The refrigerant diffusion slit 35b of the plate-shaped member 25 forms a second refrigerant diffusion space 38b. When viewed in the plate thickness direction, the second refrigerant diffusion spaces 38a, 38b overlap with the first refrigerant diffusion space 37 but do not overlap with the connecting pipe holes 34a-34d. When viewed in the plate thickness direction, the second refrigerant diffusion space 38a extends from one end of the first refrigerant diffusion space 37 to both sides in the parallel arrangement direction of the heat transfer tubes 10. The second refrigerant diffusion space 38b extends from the other end of the first refrigerant diffusion space 37 to both sides in the parallel arrangement direction of the heat transfer tubes 10. In other words, both second refrigerant diffusion spaces 38a, 38b extend in a direction intersecting the extension direction of the first refrigerant diffusion space 37. The second refrigerant diffusion spaces 38a, 38b are configured to diffuse the refrigerant flowing in from each of the connection pipes 141a to 141d in the parallel direction of the heat transfer tubes 10. When viewed in the thickness direction, the second refrigerant diffusion spaces 38a, 38b, which are arranged so as to overlap one first refrigerant diffusion space 37, are also arranged so as to overlap one distribution chamber.

[0062] The first refrigerant diffusion space 37 and the second refrigerant diffusion spaces 38a, 38b form a refrigerant diffusion space 39 that diffuses the refrigerant. The refrigerant diffusion space 39 is provided between each of the connecting pipe holes 34a-34d and the corresponding distribution chambers 32a-32d in the refrigerant flow direction. The first refrigerant diffusion space 37 is provided between each of the connecting pipe holes 34a-34d and the corresponding second refrigerant diffusion spaces 38a, 38b. The second refrigerant diffusion spaces 38a, 38b are provided between the first refrigerant diffusion space 37 and the corresponding distribution chambers 32a-32d.

[0063] The flow of refrigerant in the above configuration will be described using the distribution chamber 32c shown in Figures 8 and 9 as an example. The gas-liquid two-phase refrigerant that flows into the secondary distributor 20 from the connecting pipe 141a first flows into the first refrigerant diffusion space 37, collides with the collision wall 40, and is diffused in the longitudinal direction of the heat transfer tubes 10. The refrigerant that reaches one end of the first refrigerant diffusion space 37 flows into the second refrigerant diffusion space 38a, is diffused in the parallel direction of the heat transfer tubes 10, and flows into the distribution chamber 32c. Meanwhile, the refrigerant that reaches the other end of the first refrigerant diffusion space 37 flows into the second refrigerant diffusion space 38b, is diffused in the parallel direction of the heat transfer tubes 10, and flows into the distribution chamber 32c. The refrigerant that has been diffused in the parallel direction of the heat transfer tubes 10 by the second refrigerant diffusion spaces 38a and 38b flows into the distribution chamber 32c. The refrigerant in the distribution chamber 32c is then distributed to each of the heat transfer tubes 10.

[0064] In this embodiment, in addition to obtaining the same effects as in the first embodiment, the second refrigerant diffusion spaces 38a, 38b promote the diffusion of the refrigerant in the parallel direction of the heat transfer tubes 10, and the refrigerant flows into each of the distribution chambers 32a-32d in this state. Therefore, the deviation in the distribution of the refrigerant from each of the distribution chambers 32a-32d to the heat transfer tubes 10 can be further reduced.

[0065] As described above, in the refrigeration cycle apparatus according to this embodiment, the secondary distributor 20 is provided with connecting pipe holes 34a-34d, each of which is connected to one connecting pipe, corresponding to each of the plurality of distribution chambers 32a-32d. The secondary distributor 20 is provided with refrigerant diffusion spaces 39, each of which is provided between the connecting pipe holes 34a-34d and each of the plurality of distribution chambers 32a-32d in the refrigerant flow direction. The refrigerant diffusion space 39 includes a first refrigerant diffusion space 37 and second refrigerant diffusion spaces 38a, 38b, each of which is provided between the first refrigerant diffusion space 37 and each of the plurality of distribution chambers 32a-32d in the refrigerant flow direction. When viewed parallel to the extension direction of the plurality of heat transfer tubes 10, the first refrigerant diffusion space 37 extends from the connecting pipe holes 34a-34d on both sides along the first direction. When viewed parallel to the extension direction of the heat transfer tubes 10, the second refrigerant diffusion spaces 38a, 38b extend from the ends of the first refrigerant diffusion space 37 to both sides along a second direction that intersects with the first direction.

[0066] According to this configuration, the second refrigerant diffusion spaces 38a, 38b promote the diffusion of the refrigerant in the parallel arrangement direction of the heat transfer tubes 10. Therefore, the deviation in the distribution of the refrigerant to the plurality of heat transfer tubes 10 can be further reduced.

[0067] Embodiment 3 A refrigeration cycle apparatus according to a third embodiment will be described. Fig. 10 is a schematic diagram showing the configuration of a primary distributor and a heat exchanger of a refrigeration cycle apparatus according to this embodiment. The up-down direction in Fig. 10 represents the vertical up-down direction. Fig. 11 is a bottom view showing the configuration of a heat exchanger of a refrigeration cycle apparatus according to this embodiment. Fig. 12 is a top view showing the configuration of a heat exchanger of a refrigeration cycle apparatus according to this embodiment. Figs. 11 and 12 also show the arrangement of a blower fan 160 that supplies air to a heat exchanger 150.

[0068] As shown in FIGS. 10 to 12, the heat exchanger 150 is formed into a U-shape as a whole when viewed from above. The heat transfer tubes 10 are arranged side by side in a U-shape when viewed from above. The gas header 12 is bent into a U-shape when viewed from above. The gas header 12 has a cylindrical shape and can be easily bent. The gas header 12 is connected to the upper end of each heat transfer tube 10.

[0069] The secondary distributor 20 has a configuration in which a plurality of plate-like members are stacked, similar to the first or second embodiment. The secondary distributor 20 is divided into a plurality of sub-distributors 20a, 20b, and 20c in the parallel arrangement direction of the heat transfer tubes 10. The sub-distributors 20a, 20b, and 20c are arranged in a U-shape when viewed from above, and are connected to the lower ends of the heat transfer tubes 10.

[0070] Sub-distributor 20a is formed with one distribution chamber 32a and is connected to one connecting pipe 141a. Sub-distributor 20b is formed with two distribution chambers 32b and 32c and is connected to two connecting pipes 141b and 141c. Sub-distributor 20c is formed with one distribution chamber 32d and is connected to one connecting pipe 141d.

[0071] As described above, in the refrigeration cycle apparatus according to this embodiment, the secondary distributor 20 is divided into a plurality of sub-distributors 20a, 20b, and 20c in the parallel arrangement direction of the heat transfer tubes 10. At least one of the plurality of distribution chambers 32a, 32b, 32c, and 32d is formed in each of the sub-distributors 20a, 20b, and 20c.

[0072] If the secondary distributor 20 is a stacked horizontal distributor, it is difficult to bend the secondary distributor 20 into a U-shape, L-shape, etc. when viewed from above. In this embodiment, the secondary distributor 20 is divided into multiple sub-distributors 20a, 20b, and 20c, so the secondary distributor 20 can be easily arranged in a U-shape, L-shape, etc. when viewed from above. Therefore, in this embodiment, the degree of freedom in arranging the heat exchanger 150 can be improved. [Explanation of symbols]

[0073] 10 heat transfer tube, 11 heat transfer fin, 12 gas header, 20 secondary distributor, 20a sub-distributor, 20b sub-distributor, 20c sub-distributor, 21 plate-shaped member, 22 plate-shaped member, 23 plate-shaped member, 24 plate-shaped member, 25 plate-shaped member, 26 plate-shaped member, 31 slit, 32a to 32d distribution chamber, 32a1 to 32d1 opening, 33a to 33d refrigerant inlet hole, 33a1 central axis, 34a to 34d connection piping hole, 35a refrigerant diffusion slit, 35b refrigerant diffusion slit, 36 refrigerant diffusion slit, 37 first refrigerant diffusion space, 38a second refrigerant diffusion space, 38b second refrigerant diffusion space, 39 refrigerant diffusion space, 40 collision wall, 110 compressor, 120 heat exchanger, 130 throttle device, 140 Primary distributor, 141a-141d connecting piping, 150 heat exchanger, 160 blower fan.

Claims

1. a primary distributor that primarily distributes the refrigerant; a heat exchanger into which the refrigerant primarily distributed by the primary distributor flows; a plurality of connecting pipes connecting the primary distributor and the heat exchanger; Equipped with The heat exchanger comprises: A plurality of heat transfer tubes extending in the vertical direction; a secondary distributor connected to lower ends of the plurality of heat transfer tubes and secondarily distributing the refrigerant primarily distributed by the primary distributor to the plurality of heat transfer tubes; It has The secondary distributor has a plurality of distribution chambers formed therein, Each of the plurality of distribution chambers is connected to one of the plurality of connection pipes and n heat transfer tubes of the plurality of heat transfer tubes, n is an integer of 2 or more, a sum of the cross-sectional flow areas of the n heat transfer tubes is 10 times or less the cross-sectional flow area of ​​the one connecting pipe; the secondary distributor has a configuration in which a plurality of plate-like members are stacked, The secondary distributor is provided with connection pipe holes to which the one connection pipe is connected, the connection pipe holes corresponding to the plurality of distribution chambers, The secondary distributor has refrigerant diffusion spaces formed between the connecting pipe holes and each of the plurality of distribution chambers in the refrigerant flow, the refrigerant diffusion space includes a first refrigerant diffusion space and a second refrigerant diffusion space provided between the first refrigerant diffusion space and each of the plurality of distribution chambers in a refrigerant flow; When viewed parallel to the extension direction of the heat transfer tubes, the first refrigerant diffusion space extends on both sides from the connecting piping hole along a first direction, and the second refrigerant diffusion space extends on both sides from an end of the first refrigerant diffusion space along a second direction intersecting the first direction.

2. a primary distributor that primarily distributes the refrigerant; a heat exchanger into which the refrigerant primarily distributed by the primary distributor flows; a plurality of connecting pipes connecting the primary distributor and the heat exchanger; Equipped with The heat exchanger comprises: A plurality of heat transfer tubes extending in the vertical direction; a secondary distributor connected to lower ends of the plurality of heat transfer tubes and secondarily distributing the refrigerant primarily distributed by the primary distributor to the plurality of heat transfer tubes; It has The secondary distributor has a plurality of distribution chambers formed therein, Each of the plurality of distribution chambers is connected to one of the plurality of connection pipes and n heat transfer tubes of the plurality of heat transfer tubes, n is an integer of 2 or more, a mass flux of the refrigerant flowing through each of the n heat transfer tubes is 10 times or less than a mass flux of the refrigerant flowing through the one connecting pipe; the secondary distributor has a configuration in which a plurality of plate-like members are stacked, The secondary distributor is provided with connection pipe holes to which the one connection pipe is connected, the connection pipe holes corresponding to the plurality of distribution chambers, The secondary distributor has refrigerant diffusion spaces formed between the connecting pipe holes and each of the plurality of distribution chambers in the refrigerant flow, the refrigerant diffusion space includes a first refrigerant diffusion space and a second refrigerant diffusion space provided between the first refrigerant diffusion space and each of the plurality of distribution chambers in a refrigerant flow; When viewed parallel to the extension direction of the heat transfer tubes, the first refrigerant diffusion space extends on both sides from the connecting piping hole along a first direction, and the second refrigerant diffusion space extends on both sides from an end of the first refrigerant diffusion space along a second direction intersecting the first direction.

3. 3. The refrigeration cycle device according to claim 1, wherein each of the plurality of distribution chambers is provided with a refrigerant inlet hole through which the refrigerant flows from the single connecting pipe, and a collision wall arranged opposite the refrigerant inlet hole and against which the refrigerant flowing in from the refrigerant inlet hole collides.

4. The refrigeration cycle device according to claim 3, wherein the refrigerant inlet holes are provided at the center of each of the plurality of distribution chambers in the direction in which the plurality of heat transfer tubes are arranged side by side.

5. The refrigeration cycle device according to claim 3, wherein the refrigerant inlet holes are provided below each of the plurality of distribution chambers.

6. the secondary distributor is divided into a plurality of sub-distributors in a parallel direction of the plurality of heat transfer tubes, 3. The refrigeration cycle apparatus according to claim 1, wherein each of the plurality of sub-distributors is formed with at least one of the plurality of distribution chambers.

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