Heat Exchanger Including Refrigerant Branch Distribution Device, and Refrigeration Cycle Apparatus

Abstract

A refrigeration cycle apparatus is provided with a branch distribution portion configured to divide refrigerant in a two-phase state of liquid refrigerant and gas refrigerant into refrigerants having different liquid ratios. The branch distribution portion includes a pipe including a bent pipe, a branch pipe, a pipe, and a pipe. The refrigerant flowing through the pipe flows through the bent pipe and the branch pipe, thereby being divided into refrigerant having a high liquid ratio and refrigerant having a low liquid ratio. The refrigerant having a high liquid ratio is fed through a pipe to a heat exchanger having a large volume of air. The refrigerant having a low liquid ratio is fed through a pipe to a heat exchanger having a small volume of air.

Claims

1. A heat exchanger comprising a refrigerant branch distribution device, the refrigerant branch distribution device comprising: a first flow path, a second flow path and a third flow path; a branch portion connected to the first flow path and connected to the second flow path and the third flow path, the branch portion being configured to divide refrigerant so as to flow into the second flow path and the third flow path, the refrigerant including liquid refrigerant and gas refrigerant and flowing from the first flow path, when a ratio of the liquid refrigerant in a weight ratio between the liquid refrigerant and the gas refrigerant is defined as a liquid ratio, a first liquid ratio of first refrigerant flowing into the second flow path being higher than a second liquid ratio of second refrigerant flowing into the third flow path; a first distribution device provided in the second flow path and configured to further divide the first refrigerant flowing into the second flow path; a second distribution device provided in the third flow path and configured to further divide the second refrigerant flowing into the third flow path; a first heat exchanger connected to the second flow path and configured to perform heat exchange between the first refrigerant divided by the first distribution device and a first fluid; and a second heat exchanger connected to the third flow path and configured to perform heat exchange between the second refrigerant divided by the second distribution device and a second fluid, an amount of the first fluid being larger than an amount of the second fluid.

2. The heat exchanger according to claim 1, wherein the first flow path comprises a curved first bent portion, the second flow path is connected to a first position of the branch portion corresponding to an outer circumferential side of the first bent portion, and the third flow path is connected to a second position of the branch portion corresponding to an inner circumferential side of the first bent portion.

3. The heat exchanger according to claim 2, wherein the first flow path comprises a straight portion between the first bent portion and the branch portion, and a length L of the straight portion is set at L<10D, where D represents an inner diameter of the first flow path.

4. The heat exchanger according to claim 1, wherein the branch portion comprises: a first extending portion extending from a portion of the branch portion to which the first flow path is connected, in a first direction in which the first flow path extends; and a second extending portion branching off and extending from the first extending portion in a second direction intersecting with the first direction, the second flow path is connected to the first extending portion, and the third flow path is connected to the second extending portion.

5. The heat exchanger according to claim 4, wherein the second flow path comprises a second bent portion.

6. The heat exchanger according to claim 4, wherein an orifice is arranged in the first flow path.

7. The heat exchanger according to claim 1, wherein the branch portion comprises at least: a third extending portion branching off and extending from a portion of the branch portion to which the first flow path is connected, in a third direction intersecting with a first direction in which the first flow path extends; and a fourth extending portion branching off and extending from the portion of the branch portion to which the first flow path is connected, in a fourth direction intersecting with the first direction and the third direction, the branch portion is arranged, with the third extending portion located on an upper side and the fourth extending portion located on a lower side, the second flow path is connected to the fourth extending portion, and the third flow path is connected to the third extending portion.

8. The heat exchanger according to claim 7, wherein the second flow path comprises a third bent portion.

9. The heat exchanger according to claim 7, wherein an orifice is arranged in the first flow path.

10. The heat exchanger according to claim 1, wherein the branch portion comprises at least: a third extending portion branching off and extending from a portion of the branch portion to which the first flow path is connected, in a third direction intersecting with a first direction in which the first flow path extends; and a fourth extending portion branching off and extending from the portion of the branch portion to which the first flow path is connected, in a fourth direction opposite to the third direction, the second flow path is connected to the third extending portion, and the third flow path is connected to the fourth extending portion.

11. The heat exchanger according to claim 10, wherein the second flow path comprises a fourth bent portion.

12. The heat exchanger according to claim 10, wherein an orifice is arranged in the first flow path.

13. The heat exchanger according to claim 1, wherein the branch portion comprises a tubular body, the tubular body comprises an upper surface portion, a lower surface portion and a side surface portion, the first flow path is connected to the side surface portion, the second flow path is connected to the lower surface portion, and the third flow path is connected to the upper surface portion.

14. The heat exchanger according to claim 13, wherein the second flow path comprises a fifth bent portion.

15. (canceled)

16. A refrigeration cycle apparatus comprising the heat exchanger as recited in claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 shows a configuration of a refrigeration cycle apparatus including an outdoor unit provided with a refrigerant distribution device according to a first embodiment.

[0018] FIG. 2 is a perspective view showing the outdoor unit in the first embodiment.

[0019] FIG. 3 is a perspective view showing one example of the relation between a volume of air introduced into an outdoor heat exchanger and the heat exchanger in the first embodiment.

[0020] FIG. 4 shows one example of a routing structure of heat transfer tubes in a part of the outdoor heat exchanger, and one example of the connection relation between a part of the outdoor heat exchanger and a branch distribution portion in the first embodiment.

[0021] FIG. 5 shows one example of the connection relation between the outdoor heat exchanger and the branch distribution portion in the first embodiment.

[0022] FIG. 6 is a partial view showing the branch distribution portion arranged in the outdoor unit in the first embodiment.

[0023] FIG. 7 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line VII-VII shown in FIG. 6 in the first embodiment.

[0024] FIG. 8 is a partial view showing a refrigerant distribution device including a branch distribution portion arranged in an outdoor unit according to a second embodiment.

[0025] FIG. 9 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line IX-IX shown in FIG. 8 in the second embodiment.

[0026] FIG. 10 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line X-X shown in FIG. 8 in the second embodiment.

[0027] FIG. 11 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XI-XI shown in FIG. 8 in the second embodiment.

[0028] FIG. 12 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XII-XII shown in FIG. 8 in the second embodiment.

[0029] FIG. 13 is a partial view showing a branch distribution portion arranged in an outdoor unit according to a modification of the second embodiment.

[0030] FIG. 14 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XIV-XIV shown in FIG. 13 in the second embodiment.

[0031] FIG. 15 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XV-XV shown in FIG. 13 in the second embodiment.

[0032] FIG. 16 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XVI-XVI shown in FIG. 13 in the second embodiment.

[0033] FIG. 17 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XVII-XVII shown in FIG. 13 in the second embodiment.

[0034] FIG. 18 is a partial view showing a branch distribution portion arranged in an outdoor unit according to a third embodiment.

[0035] FIG. 19 is a cross-sectional view of an orifice according to a first example used in the branch distribution portion, along a cross-sectional line XIX-XIX shown in FIG. 18 in the third embodiment.

[0036] FIG. 20 is a cross-sectional view of an orifice according to a second example used in the branch distribution portion, along the cross-sectional line XIX-XIX shown in FIG. 18 in the third embodiment.

[0037] FIG. 21 is a cross-sectional view of an orifice according to a third example used in the branch distribution portion, along the cross-sectional line XIX-XIX shown in FIG. 18 in the third embodiment.

[0038] FIG. 22 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXII-XXII shown in FIG. 18 in the third embodiment.

[0039] FIG. 23 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXIII-XXIII shown in FIG. 18 in the third embodiment.

[0040] FIG. 24 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XXIV-XXIV shown in FIG. 18 in the third embodiment.

[0041] FIG. 25 is a partial view showing a refrigerant distribution device including a branch distribution portion arranged in an outdoor unit according to a fourth embodiment.

[0042] FIG. 26 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXVI-XXVI shown in FIG. 25 in the fourth embodiment.

[0043] FIG. 27 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXVII-XXVII shown in FIG. 25 in the fourth embodiment.

[0044] FIG. 28 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXVIII-XXVIII shown in FIG. 25 in the fourth embodiment.

[0045] FIG. 29 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXIX-XXIX shown in FIG. 25 in the fourth embodiment.

[0046] FIG. 30 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXX-XXX shown in FIG. 25 in the fourth embodiment.

[0047] FIG. 31 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XXXI-XXXI shown in FIG. 25 in the fourth embodiment.

[0048] FIG. 32 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XXXII-XXXII shown in FIG. 25 in the fourth embodiment.

[0049] FIG. 33 is a partial view showing a branch distribution portion arranged in an outdoor unit according to a modification of the fourth embodiment.

[0050] FIG. 34 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXXIV-XXXIV shown in FIG. 33 in the fourth embodiment.

[0051] FIG. 35 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXXV-XXXV shown in FIG. 33 in the fourth embodiment.

[0052] FIG. 36 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXXVI-XXXVI shown in FIG. 33 in the fourth embodiment.

[0053] FIG. 37 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXXVII-XXXVII shown in FIG. 33 in the fourth embodiment.

[0054] FIG. 38 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XXXVIII-XXXVIII shown in FIG. 33 in the fourth embodiment.

[0055] FIG. 39 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XXXIX-XXXIX shown in FIG. 33 in the fourth embodiment.

[0056] FIG. 40 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XL-XL shown in FIG. 33 in the fourth embodiment.

[0057] FIG. 41 is a partial view showing a branch distribution portion arranged in an outdoor unit according to a fifth embodiment.

[0058] FIG. 42 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XLII-XLII shown in FIG. 41 in the fifth embodiment.

[0059] FIG. 43 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XLIII-XLIII shown in FIG. 41 in the fifth embodiment.

[0060] FIG. 44 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XLIV-XLIV shown in FIG. 41 in the fifth embodiment.

[0061] FIG. 45 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XLV-XLV shown in FIG. 41 in the fifth embodiment.

[0062] FIG. 46 is a cross-sectional view showing one example of distribution of refrigerant in a pipe along a cross-sectional line XLVI-XLVI shown in FIG. 41 in the fifth embodiment.

[0063] FIG. 47 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XLVII-XLVII shown in FIG. 41 in the fifth embodiment.

[0064] FIG. 48 is a cross-sectional view showing one example of distribution of refrigerant in pipes along a cross-sectional line XLVIII-XLVIII shown in FIG. 41 in the fifth embodiment.

DETAILED DESCRIPTION

First Embodiment

[0065] A refrigeration cycle apparatus including a refrigerant distribution device according to a first embodiment will be described. First, a configuration of the refrigeration cycle apparatus will be described. A multi air conditioner for buildings will be described as an example of the refrigeration cycle apparatus.

[0066] As shown in FIG. 1, in a multi air conditioner for buildings serving as a refrigeration cycle apparatus 1, a plurality of indoor heat exchangers 15a, 15b, 15c, and 15d (15) are connected to one outdoor heat exchanger 7. In addition to outdoor heat exchanger 7 and indoor heat exchangers 15, refrigeration cycle apparatus 1 includes a compressor 3, four-way valves 5a and 5b, indoor fans 19a, 19b, 19c, and 19d, expansion valves 13a, 13b, 13c, and 13d, expansion valves 9a and 9b, refrigerant distribution devices 21a and 21b, an outdoor fan 17, and an accumulator 23.

[0067] Furthermore, in refrigeration cycle apparatus 1, a branch distribution portion 11 is provided between refrigerant distribution devices 21a and 21b and expansion valve 13. Branch distribution portion 11 will be described below. Expansion valves 9a and 9b provided between branch distribution portion 11 and refrigerant distribution devices 21a and 21b are not essential and are provided as needed.

[0068] Next, as the operation of the multi air conditioner for buildings, heating operation will be described. By driving compressor 3, high-temperature and high-pressure gaseous refrigerant is discharged from compressor 3. The discharged high-temperature and high-pressure gas refrigerant (single phase) flows through four-way valves 5a and 5b into each of the plurality of indoor heat exchangers 15a, 15b, 15c, and 15d.

[0069] Air is introduced into indoor heat exchangers 15a to 15d by indoor fans 19a, 19b, 19c, and 19d, respectively. In each of indoor heat exchangers 15a to 15d, heat exchange is performed between the introduced air and the gas refrigerant flowing into each of indoor heat exchangers 15a to 15d, and the high-temperature and high-pressure gas refrigerant condenses to high-pressure liquid refrigerant (single phase). As a result of this heat exchange, each of the rooms where indoor heat exchangers 15a to 15d are arranged is heated.

[0070] Next, the high-pressure liquid refrigerant discharged from indoor heat exchangers 15a to 15d passes through expansion valves 13a, 13b, 13c, and 13d, to thereby become refrigerant in a two-phase state of low-pressure gas refrigerant and liquid refrigerant.

[0071] The refrigerant in a two-phase state flows into an outdoor unit 25. The refrigerant in a two-phase state flowing into outdoor unit 25 is divided into two in branch distribution portion 11. One refrigerant (refrigerant A), of the refrigerant divided into two, flows through expansion valve 9a, refrigerant distribution device 21a and pipes 47 into outdoor heat exchanger 7a. The other refrigerant (refrigerant B), of the refrigerant divided into two, flows through expansion valve 9b, refrigerant distribution device 21b and pipes 48 into outdoor heat exchanger 7b.

[0072] In outdoor heat exchangers 7a and 7b, heat exchange is performed between air introduced by outdoor fan 17 and the refrigerant (refrigerant A and refrigerant B) flowing into outdoor heat exchangers 7a and 7b, and the liquid refrigerant of the refrigerant in a two-phase state evaporates to low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant discharged from outdoor unit 25 flows through four-way valves 5a and 5b and accumulator 23 into compressor 3. The low-pressure gas refrigerant flowing into compressor 3 is compressed to high-temperature and high-pressure gas refrigerant, which is again discharged from compressor 3. Thereafter, this cycle is repeated.

[0073] Next, cooling operation will be described. The high-temperature and high-pressure gas refrigerant compressed by compressor 3 flows through four-way valves 5a and 5b into outdoor heat exchangers 7a and 7b. In outdoor heat exchangers 7a and 7b, heat exchange is performed between the air introduced by outdoor fan 17 and the gas refrigerant flowing into outdoor heat exchangers 7a and 7b, and the high-temperature and high-pressure gas refrigerant condenses to low-temperature and high-pressure liquid refrigerant (single phase).

[0074] The low-temperature and high-pressure liquid refrigerant passes through expansion valves 13a to 13d and the like, to thereby become low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant flows into each of the plurality of indoor heat exchangers 15a to 15d. In indoor heat exchangers 15a to 15d, heat exchange is performed between the air introduced by indoor fans 19a to 19d and the liquid refrigerant flowing into indoor heat exchangers 15a to 15d, and the low-temperature and low-pressure liquid refrigerant evaporates to low-pressure gas refrigerant (single phase). As a result of this heat exchange, each of the rooms where indoor heat exchangers 15a to 15d are arranged is cooled.

[0075] The low-pressure gas refrigerant discharged from indoor heat exchangers 15a to 15d flows through four-way valves 5a and 5b and accumulator 23 into compressor 3. The low-pressure gas refrigerant flowing into the compressor is compressed to high-temperature and high-pressure gas refrigerant, which is again discharged from the compressor. Thereafter, this cycle is repeated.

[0076] In refrigeration cycle apparatus 1 described above, outdoor heat exchanger 7 of outdoor unit 25 functions as an evaporator during heating operation, and functions as a condenser during cooling operation. One example of the outdoor unit of the multi air conditioner for buildings is an outdoor unit including a top flow-type fan. As shown in FIG. 2, in top flow-type outdoor unit 25, outdoor fan 17 is attached to an upper surface portion of a housing 26.

[0077] Air inlets 27 through which the air is taken in are provided in three side surface portions (three sides) of four side surface portions of the housing. As shown in FIG. 3, outdoor heat exchanger 7 is arranged in housing 26. Outdoor heat exchanger 7 is arranged so as to face the three air inlets (side surface portions of the housing). Branch distribution portion 11, the compressor (not shown) and the like are also arranged in housing 26.

[0078] In outdoor unit 25 described above, outdoor fan 17 is attached to the upper surface portion of housing 26. Therefore, in outdoor heat exchanger 7, a pressure loss of the air becomes lower as a distance from outdoor fan 17 becomes shorter, and the pressure loss of the air becomes higher as the distance from outdoor fan 17 becomes longer. That is, the pressure loss becomes higher gradually from an upper part toward a lower part of outdoor heat exchanger 7, and thus, a volume of air passing through outdoor heat exchanger 7a is relatively large and a volume of air passing through outdoor heat exchanger 7b is relatively small (see arrows in FIG. 3).

[0079] FIG. 4 shows one example of the connection relation between outdoor heat exchanger 7a and the pipes. As shown in FIG. 4, outdoor heat exchanger 7a is formed of, for example, three rows of outdoor heat exchangers 7aa, 7ab and 7ac. Heat transfer tubes (not shown) are attached to each of the three rows of outdoor heat exchangers 7aa, 7ab and 7ac. A plurality of pipes 47 branching off from refrigerant distribution device 21a are connected to the corresponding heat transfer tubes of the first row of outdoor heat exchanger 7a, respectively.

[0080] One refrigerant path extends from the heat transfer tube of the first row of outdoor heat exchanger 7aa through the heat transfer tube of the second row of outdoor heat exchanger 7ab and the heat transfer tube of the third row of outdoor heat exchanger 7ac to a refrigerant distribution device 29. As shown in FIGS. 1 and 3, also with respect to outdoor heat exchanger 7b arranged below outdoor heat exchanger 7a, a plurality of pipes 48 branching off from refrigerant distribution device 21b are connected (see FIG. 5).

[0081] When outdoor heat exchanger 7 functions as an evaporator, it is required to allow the liquid refrigerant of the refrigerant in a two-phase state to flow into outdoor heat exchanger 7a having a larger volume of air, such that the liquid refrigerant efficiently evaporates to gas refrigerant. For this purpose, outdoor unit 25 is provided with branch distribution portion 11 as shown in FIG. 5.

[0082] In branch distribution portion 11, the refrigerant in a two-phase state flowing from indoor heat exchanger 15 is divided into two lines of refrigerant (refrigerant A and refrigerant B) during heating operation. A ratio of the liquid refrigerant in a weight ratio between the liquid refrigerant and the gas refrigerant is defined as a liquid ratio. Refrigerant A is refrigerant having a high liquid ratio. Refrigerant B is refrigerant having a low liquid ratio. In branch distribution portion 11, the refrigerant is macroscopically divided into refrigerant A having a high liquid ratio and refrigerant B having a low liquid ratio. Refrigerant A is further divided microscopically by refrigerant distribution device 21a and fed to outdoor heat exchanger 7a having a large volume of air. Refrigerant B is further divided microscopically by refrigerant distribution device 21b and fed to outdoor heat exchanger 7b having a small volume of air.

[0083] A first example of a specific structure of branch distribution portion 11 will be described. As shown in FIG. 6, branch distribution portion 11 includes a pipe 41 (first flow path) including a bent pipe 33, a branch pipe 31 (branch portion), a pipe 43 (second flow path), and a pipe 44 (third flow path). The refrigerant in a two-phase state flowing through pipe 41 flows through bent pipe 33, which causes non-uniformity in distribution of the liquid refrigerant. That is, due to the centrifugal force, an amount of the liquid refrigerant flowing along an inner wall surface on the outer circumferential side of bent pipe 33 becomes larger than an amount of the liquid refrigerant flowing along an inner wall surface on the inner circumferential side of bent pipe 33.

[0084] As a result, in pipe 41 immediately after the refrigerant flows through bent pipe 33, the refrigerant (refrigerant A) having a high liquid ratio flows through a region corresponding to the outer circumferential side of bent pipe 33, and the refrigerant (refrigerant B) having a low liquid ratio flows through a region corresponding to the inner circumferential side of bent pipe 33. The refrigerant flowing through pipe 41 in this state is divided into refrigerant A and refrigerant B by branch pipe 31. Divided refrigerant A flows through pipe 43, refrigerant distribution device 21a and pipes 47 into outdoor heat exchanger 7a. On the other hand, refrigerant B flows through pipe 44, refrigerant distribution device 21b and pipes 48 into outdoor heat exchanger 7b.

[0085] In this way, in outdoor unit 25, refrigerant A having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air. As a result, heat exchange between the refrigerant in a two-phase state and the air can be performed efficiently.

[0086] As a method for allowing the refrigerant having a high liquid ratio to flow into outdoor heat exchanger 7a having a larger volume of air, there has conventionally been a method for adjusting a pressure loss by changing a length of the pipes, an inner diameter of the pipes or the like connected to outdoor heat exchangers 7a and 7b. That is, there has been a method for dividing the refrigerant microscopically. However, according to this method, when the number of pipes increases, it becomes difficult to adjust the length of the pipes. In addition, a region for routing the pipes is also required. Furthermore, routing of the pipes is also complicated.

[0087] In contrast to such a method, the above-described method using branch distribution portion 11 can allow the refrigerant having a high liquid ratio to flow into outdoor heat exchanger 7a having a larger volume of air, with a simple structure of bent pipe 33 and branch pipe 31.

[0088] A length L of a straight portion of pipe 41 extending from bent pipe 33 to branch pipe 31 needs to be set at such a length that the liquid refrigerant in pipe 41 flows into branch pipe 31 with non-uniform and uneven distribution (see FIG. 7). Length L of the straight portion needs to satisfy the relation of L<10D, where D represents an inner diameter of the bent pipe. When length L of the straight portion is L10D, the liquid refrigerant returns from the non-uniformly and unevenly distributed state to a state in which the liquid refrigerant is annularly distributed almost evenly along an inner wall of pipe 41. Therefore, a larger amount of liquid refrigerant cannot be introduced into outdoor heat exchanger 7a.

[0089] As shown in FIG. 1, expansion valves 9a and 9b may be provided between refrigerant distribution devices 21a and 21b and branch distribution portion 11. Particularly by adjusting a degree of opening of expansion valve 9a, it is possible to prevent the liquid refrigerant from flowing through pipe 43 excessively.

Second Embodiment

[0090] A second example of the branch distribution portion forming the refrigerant branch distribution device will now be described. As shown in FIG. 8, branch distribution portion 11 includes a T-shaped branch pipe 35a (35) (branch portion) having a shape similar to the shape of alphabetical T. T-shaped branch pipe 35a includes a portion extending in one direction (pipe portion A), and a portion branching off from pipe portion A in a direction almost orthogonal to the one direction.

[0091] Pipe 43 (second flow path) including bent pipe 33 is connected to pipe portion A. Refrigerant distribution device 21a is connected to pipe 43, and further, a plurality of pipes 47 are connected to refrigerant distribution device 21a. On the other hand, pipe 44 (third flow path) is connected to pipe portion B. Refrigerant distribution device 21b is connected to pipe 44, and further, a plurality of pipes 48 are connected to refrigerant distribution device 21b. The plurality of pipes 47 are connected to outdoor heat exchanger 7a, and the plurality of pipes 48 are connected to outdoor heat exchanger 7b (see FIG. 3).

[0092] Since the remaining configuration of the outdoor unit and the remaining configuration of the refrigeration cycle apparatus are similar to the configurations shown in FIGS. 1 and 3, description thereof will not be repeated except when necessary.

[0093] In branch distribution portion 11 described above, when the refrigerant in a two-phase state flowing through pipe 41 (first flow path) flows into T-shaped branch pipe 35a, a larger amount of liquid refrigerant flows through pipe portion A extending in one direction, due to the inertia. As a result, as shown in FIG. 9, the refrigerant (refrigerant A) having a high liquid ratio flows into pipe 43 connected to pipe portion A.

[0094] On the other hand, a larger amount of gas refrigerant flows through pipe portion B branching off from pipe portion A. As a result, as shown in FIG. 10, the refrigerant (refrigerant B) having a low liquid ratio flows into pipe 44 connected to pipe portion B.

[0095] The refrigerant (refrigerant A) in a two-phase state having a high liquid ratio and flowing through pipe 43 flows through bent pipe 33. At this time, non-uniformity occurs in the distribution of the liquid refrigerant included in refrigerant A. That is, as described above, due to the centrifugal force, an amount of the liquid refrigerant flowing along an inner wall surface on the outer circumferential side of bent pipe 33 becomes larger than an amount of the liquid refrigerant flowing along an inner wall surface on the inner circumferential side of bent pipe 33.

[0096] As a result, as shown in FIG. 11, in pipe 43 immediately after the refrigerant flows through bent pipe 33, the refrigerant (refrigerant AA) having a high liquid ratio flows through a region corresponding to the outer circumferential side, and the refrigerant (refrigerant AB) having a low liquid ratio flows through a region corresponding to the inner circumferential side.

[0097] The refrigerant (refrigerant AA and refrigerant AB) flowing through pipe 43 flows into refrigerant distribution device 21a in this state. In refrigerant distribution device 21a, the refrigerant flowing into refrigerant distribution device 21a is divided so as to flow into the plurality of pipes 47. At this time, as shown in FIG. 12, refrigerant AA having a high liquid ratio flows into pipe 47 arranged at a position corresponding to the outer circumferential side of the bent pipe, of the plurality of pipes 47. On the other hand, refrigerant AB having a low liquid ratio flows into pipe 47 arranged at a position corresponding to the inner circumferential side of the bent pipe.

[0098] Divided refrigerant AA and refrigerant AB flow through pipes 47 into outdoor heat exchanger 7a. On the other hand, refrigerant B flows through pipes 48 into outdoor heat exchanger 7b. In this way, in outdoor unit 25, refrigerant A (refrigerant AA and refrigerant AB) having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air.

[0099] Particularly, in outdoor heat exchanger 7a, refrigerant AA having a high liquid ratio flows through an upper path of outdoor heat exchanger 7a having a relatively large volume of air, and refrigerant AB having a low liquid ratio flows through a lower path of outdoor heat exchanger 7a having a relatively small volume of air (see FIG. 5). As a result, heat exchange between the refrigerant and the air can be performed more efficiently.

Modification

[0100] A modification of the T-shaped branch pipe will now be described. As shown in FIG. 13, in a T-shaped branch pipe 35b (branch portion) according to the modification, two portions (pipe portion B and pipe portion C) branch off from a portion (pipe portion A) extending in one direction. Pipe 45 (fourth flow path) is connected to pipe portion C. A refrigerant distribution device 21c is connected to pipe 45, and further, a plurality of pipes 49 are connected to refrigerant distribution device 21c. The plurality of pipes 49 are connected to outdoor heat exchanger 7b together with pipes 48, for example.

[0101] The remaining configuration of T-shaped branch pipe 35b and the like is similar to the configuration shown in FIG. 8, and the remaining configuration of the outdoor unit and the remaining configuration of the refrigeration cycle apparatus are similar to the configurations shown in FIGS. 1 and 3. Therefore, the same members are denoted by the same reference characters and description thereof will not be repeated except when necessary.

[0102] In branch distribution portion 11 described above, when the refrigerant in a two-phase state flowing through pipe 41 (first flow path) flows into T-shaped branch pipe 35b, liquid refrigerant 51 is more likely to flow through pipe 43 (second flow path) connected to pipe portion A by the inertia as described above, and thus, the refrigerant (refrigerant A) having a high liquid ratio flows into pipe 43.

[0103] On the other hand, the liquid refrigerant is less likely to flow through pipe portion B and pipe portion C branching off from pipe portion A, and thus, the refrigerant (refrigerant B) having a low liquid ratio flows through pipe portion B and pipe portion C. When pipe portion B is compared with pipe portion C, the gas refrigerant is likely to flow into pipe portion C located on the upstream side of the refrigerant flow, and thus, the refrigerant having a low liquid ratio flows into pipe portion C. The refrigerant having a high liquid ratio flows into pipe portion B located on the downstream side of the refrigerant flow.

[0104] As a result, as shown in FIG. 14, the refrigerant (refrigerant BB) having a low liquid ratio flows into pipe 45 connected to pipe portion C. As shown in FIG. 15, the refrigerant (refrigerant BA) having a high liquid ratio flows into pipe 44 (third flow path) connected to pipe portion B.

[0105] The refrigerant (refrigerant BB) flowing through pipe 45 flows into refrigerant distribution device 21c. In refrigerant distribution device 21c, the refrigerant flowing into refrigerant distribution device 21c is divided so as to flow into the plurality of pipes 49. The refrigerant (refrigerant BA) flowing through pipe 44 flows into refrigerant distribution device 21b. In refrigerant distribution device 21b, the refrigerant flowing into refrigerant distribution device 21b is divided so as to flow into the plurality of pipes 48.

[0106] As described above, refrigerant A flowing through pipe 43 is divided so as to flow into the plurality of pipes 47 by refrigerant distribution device 21a. As shown in FIG. 16, in pipe 43 immediately after the refrigerant flows through bent pipe 33, the refrigerant (refrigerant AA) having a high liquid ratio flows through a region corresponding to the outer circumferential side, and the refrigerant (refrigerant AB) having a low liquid ratio flows through a region corresponding to the inner circumferential side.

[0107] In addition, as shown in FIG. 17, refrigerant AA having a high liquid ratio flows into pipe 47 arranged at a position corresponding to the outer circumferential side of the bent pipe, of the plurality of pipes 47. Refrigerant AB having a low liquid ratio flows into pipe 47 arranged at a position corresponding to the inner circumferential side of the bent pipe. Refrigerant AA and refrigerant AB flow through pipes 47 into outdoor heat exchanger 7a.

[0108] On the other hand, divided refrigerant B (refrigerant BB and refrigerant BA) flows through pipes 48 and 49 into outdoor heat exchanger 7b. In this way, in outdoor unit 25, refrigerant A having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B (refrigerant BB and refrigerant BA) having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air.

[0109] Particularly, in outdoor heat exchanger 7b, refrigerant BA having a high liquid ratio flows through an upper path of outdoor heat exchanger 7b having a relatively large volume of air, and refrigerant BB having a low liquid ratio flows through a lower path of outdoor heat exchanger 7b having a relatively small volume of air (see FIG. 5). As a result, heat exchange between the refrigerant and the air can be performed more efficiently.

Third Embodiment

[0110] A third example of the branch distribution portion forming the refrigerant branch distribution device will now be described. As shown in FIG. 18, branch distribution portion 11 includes an orifice 39 in pipe 41 (first flow path) before (on the upstream side of) T-shaped branch pipe 35a (35) (branch portion). Orifice 39 includes an opening through which the refrigerant flows, in a blocking portion configured to block the flow of the refrigerant. An area (flow path cross-sectional area) of the opening of orifice 39 is smaller than a flow path cross-sectional area of pipe 41.

[0111] FIG. 19 shows a first example of orifice 39. In this orifice 39, a substantially circular opening 39b is concentrically formed in a blocking portion 39a configured to block the flow of the refrigerant. FIG. 20 shows a second example of orifice 39. In this orifice 39, substantially semicircular opening 39b is formed in blocking portion 39a configured to block the flow of the refrigerant. In this orifice 39, blocking portion 39a is arranged at a circumferential position at which pipe 44 (third flow path) is connected to T-shaped branch pipe 35a.

[0112] FIG. 21 shows a third example of orifice 39. In this orifice 39, substantially circular opening 39b is formed in blocking portion 39a configured to block the flow of the refrigerant. Substantially circular opening 39b is formed in blocking portion 39a such that a center of opening 39b deviates from a center of orifice 39. In this orifice 39, blocking portion 39a is arranged at a circumferential position at which pipe 44 is connected to T-shaped branch pipe 35a.

[0113] The remaining configuration of T-shaped branch pipe 35a and the like is similar to the configuration shown in FIG. 8, and the remaining configuration of the outdoor unit and the remaining configuration of the refrigeration cycle apparatus are similar to the configurations shown in FIGS. 1 and 3. Therefore, the same members are denoted by the same reference characters and description thereof will not be repeated except when necessary.

[0114] In branch distribution portion 11 described above, the liquid refrigerant of the refrigerant in a two-phase state flowing through pipe 41 is taken off from an inner wall of pipe 41 by blocking portion 39a of orifice 39, before the refrigerant in a two-phase state flows into T-shaped branch pipe 35a. In addition, the refrigerant passes through opening 39b having a small flow path cross-sectional area, which results in an increase in flow velocity of the refrigerant. Thus, a larger amount of liquid refrigerant is likely to flow through pipe portion A of T-shaped branch pipe 35a extending in one direction. Particularly when a flow rate of the refrigerant in a two-phase state is low, an amount of the liquid refrigerant flowing into pipe portion A can be increased.

[0115] On the other hand, since the liquid refrigerant is taken off from the inner wall of pipe 41 before pipe portion B, the liquid refrigerant is less likely to flow into pipe portion B branching off from pipe portion A, as compared with the case of not having the orifice, and a larger amount of gas refrigerant is likely to flow into pipe portion B correspondingly. As a result, as shown in FIG. 22, the refrigerant (refrigerant B) having a low liquid ratio flows into pipe 44 connected to pipe portion B.

[0116] Particularly, blocking portion 39a of orifice 39 shown in FIG. 20 or 21 is arranged at the circumferential position at which pipe 44 is connected to T-shaped branch pipe 35a, and thus, an amount of the liquid refrigerant flowing into pipe 44 can be effectively reduced and an amount of the liquid refrigerant flowing into pipe 43 (second flow path) can be increased correspondingly.

[0117] As described above, the refrigerant having a high liquid ratio and flowing into pipe 43 flows through bent pipe 33, and thus, is divided into the refrigerant (refrigerant AA) having a high liquid ratio and the refrigerant (refrigerant AB) having a low liquid ratio as shown in FIG. 23. Divided refrigerant AA and refrigerant AB are further divided by refrigerant distribution device 21a. As shown in FIG. 24, divided refrigerant AA and refrigerant AB flows through pipes 47 into outdoor heat exchanger 7a. On the other hand, refrigerant B flows through pipes 48 into outdoor heat exchanger 7b. In this way, in outdoor unit 25, heat exchange between the refrigerant and the air can be performed more efficiently.

Fourth Embodiment

[0118] A fourth example of the branch distribution portion forming the refrigerant branch distribution device will now be described. As shown in FIG. 25, branch distribution portion 11 includes a Y-shaped branch pipe 37a (37) (branch portion) having a shape similar to the shape of alphabetical Y. In Y-shaped branch pipe 37a, one pipe bifurcates into two pipes. Pipe 43 is connected to one branch pipe portion of the bifurcated pipes, and pipe 44 is connected to the other branch pipe portion. Y-shaped branch pipe 37a is arranged, with pipe 43 located on the lower side and pipe 44 located on the upper side. Each of pipes 43 and 44 includes bent pipe 33.

[0119] Since the remaining configuration of the outdoor unit and the remaining configuration of the refrigeration cycle apparatus are similar to the configurations shown in FIGS. 1 and 3, description thereof will not be repeated except when necessary.

[0120] In branch distribution portion 11 described above, the refrigerant in a two-phase state (see FIG. 26) flowing through pipe 41 (first flow path) flows into Y-shaped branch pipe 37a. The refrigerant flowing into Y-shaped branch pipe 37a is divided so as to flow into pipe 43 (second flow path) and pipe 44 (third flow path). At this time, as shown in FIG. 27, the liquid refrigerant is more likely to flow through pipe 43 located on the lower side by gravity, and thus, the refrigerant (refrigerant A) having a high liquid ratio flows into pipe 43. On the other hand, as shown in FIG. 28, the liquid refrigerant is less likely to flow through pipe 44 located on the upper side, and thus, the refrigerant (refrigerant B) having a low liquid ratio flows into pipe 44.

[0121] The refrigerant flowing through pipe 43 flows through bent pipe 33 and is further divided by refrigerant distribution device 21a. The divided refrigerant flows through pipes 47 into outdoor heat exchanger 7a. On the other hand, the refrigerant flowing through pipe 44 flows through bent pipe 33 and is further divided by refrigerant distribution device 21b. The divided refrigerant flows through pipes 48 into outdoor heat exchanger 7b.

[0122] FIG. 29 shows distribution of the refrigerant in pipe 43 immediately after the refrigerant flows through bent pipe 33 of pipe 43. FIG. 30 shows distribution of the refrigerant in pipe 44 immediately after the refrigerant flows through bent pipe 33 of pipe 44. FIG. 31 shows distribution of the refrigerant in pipes 47. FIG. 32 shows distribution of the refrigerant in pipes 48.

[0123] As shown in FIGS. 27 to 32, the refrigerant flowing into Y-shaped branch pipe 37a is divided into the refrigerant having a high liquid ratio and the refrigerant having a low liquid ratio by branch distribution portion 11. The refrigerant having a high liquid ratio flows into outdoor heat exchanger 7a, and the refrigerant having a low liquid ratio flows into outdoor heat exchanger 7b.

[0124] In this way, in outdoor unit 25, refrigerant A having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air. As a result, heat exchange between the refrigerant and the air can be performed more efficiently.

Modification

[0125] A modification of the Y-shaped branch pipe will now be described. As shown in FIG. 33, a Y-shaped branch pipe 37b (37) (branch portion) according to the modification includes a portion (pipe portion A) configured to cause the refrigerant to branch so as to have a direction component (X direction component) of a direction (e.g., X direction) of the refrigerant flow, and a portion (pipe portion B) configured to cause the refrigerant to branch so as to have a direction component (X direction component) opposite to the direction component (see the vectors shown in FIG. 33).

[0126] Structurally, Y-shaped branch pipe 37b includes a portion (pipe portion A) extending in one direction in which the refrigerant flows, a portion (pipe portion B) extending in another direction intersecting with the one direction, and a portion (pipe portion C) extending in a direction opposite to the other direction.

[0127] In branch distribution portion 11 described above, the refrigerant in a two-phase state (see FIG. 34) flowing through pipe 41 (first flow path) flows into Y-shaped branch pipe 37b. The refrigerant flowing into Y-shaped branch pipe 37b is divided so as to flow into pipe 43 (second flow path) and pipe 44 (third flow path). At this time, as shown in FIG. 35, the liquid refrigerant is more likely to flow through pipe 43 by the inertial force, and thus, the refrigerant (refrigerant A) having a high liquid ratio flows into pipe 43. On the other hand, as shown in FIG. 36, the liquid refrigerant is less likely to flow through pipe 44, and thus, the refrigerant (refrigerant B) having a low liquid ratio flows into pipe 44.

[0128] The refrigerant flowing through pipe 43 flows through bent pipe 33 and is further divided by refrigerant distribution device 21a. The divided refrigerant flows through pipes 47 into outdoor heat exchanger 7a. On the other hand, the refrigerant flowing through pipe 44 flows through bent pipe 33 and is further divided by refrigerant distribution device 21b. The divided refrigerant flows through pipes 48 into outdoor heat exchanger 7b.

[0129] FIG. 37 shows distribution of the refrigerant in pipe 43 immediately after the refrigerant flows through bent pipe 33 of pipe 43. FIG. 38 shows distribution of the refrigerant in pipe 44 immediately after the refrigerant flows through bent pipe 33 of pipe 44. FIG. 39 shows distribution of the refrigerant in pipes 47. FIG. 40 shows distribution of the refrigerant in pipes 48.

[0130] Particularly, Y-shaped branch pipe 37b has the portion (pipe portion A) configured to cause the refrigerant to branch so as to have the direction component (X direction component) of the direction (X direction) of the refrigerant flow. Therefore, even when a flow rate of the refrigerant is low, the liquid refrigerant is likely to flow by the inertial force, and thus, the refrigerant having a high liquid ratio can flow from pipe portion A to pipe 43.

[0131] Thus, in outdoor unit 25, refrigerant A having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air. As a result, heat exchange between the refrigerant and the air can be performed more efficiently.

Fifth Embodiment

[0132] A fifth example of the branch distribution portion forming the refrigerant branch distribution device will now be described. As shown in FIG. 41, branch distribution portion 11 includes a tubular body 36 (branch portion). Pipe 41 (first flow path) is connected to a side surface of tubular body 36. Pipe 43 (second flow path) is connected to a lower surface portion of tubular body 36. Pipe 44 (third flow path) is connected to an upper surface portion of tubular body 36. Each of pipes 43 and 44 includes bent pipe 33.

[0133] Since the remaining configuration of the outdoor unit and the remaining configuration of the refrigeration cycle apparatus are similar to the configurations shown in FIGS. 1 and 3, description thereof will not be repeated except when necessary.

[0134] In branch distribution portion 11 described above, the refrigerant in a two-phase state (see FIG. 42) flowing through pipe 41 flows into tubular body 36. Of the refrigerant flowing into tubular body 36, the liquid refrigerant having a high density accumulates in a lower part in tubular body 36 by gravity, and the gas refrigerant having a low density accumulates in an upper part in tubular body 36.

[0135] The refrigerant including a large amount of liquid refrigerant and accumulating in the lower part in tubular body 36 flows through pipe 43 including bent pipe 33 and is further divided by refrigerant distribution device 21a. The divided refrigerant flows through pipes 47 into outdoor heat exchanger 7a. On the other hand, the refrigerant including a large amount of gas refrigerant and accumulating in the upper part in tubular body 36 flows through pipe 44 including bent pipe 33 and is further divided by refrigerant distribution device 21b. The divided refrigerant flows through pipes 48 into outdoor heat exchanger 7b.

[0136] FIG. 43 shows distribution of the refrigerant in pipe 43 immediately after the refrigerant flows out of tubular body 36. FIG. 44 shows distribution of the refrigerant in pipe 44 immediately after the refrigerant flows out of tubular body 36. FIG. 45 shows distribution of the refrigerant in pipe 43 immediately after the refrigerant flows through bent pipe 33 of pipe 43. FIG. 46 shows distribution of the refrigerant in pipe 44 immediately after the refrigerant flows through bent pipe 33 of pipe 44. FIG. 47 shows distribution of the refrigerant in pipes 47. FIG. 48 shows distribution of the refrigerant in pipes 48.

[0137] As shown in FIGS. 43 to 48, the refrigerant flowing through pipe 41 is divided into the refrigerant having a high liquid ratio and the refrigerant having a low liquid ratio by tubular body 36, bent pipe 33 and the like. The refrigerant having a high liquid ratio flows into outdoor heat exchanger 7a, and the refrigerant having a low liquid ratio flows into outdoor heat exchanger 7b.

[0138] In this way, in outdoor unit 25, refrigerant A having a high liquid ratio flows into outdoor heat exchanger 7a having a larger volume of air, and refrigerant B having a low liquid ratio flows into outdoor heat exchanger 7b having a smaller volume of air. As a result, heat exchange between the refrigerant and the air can be performed more efficiently.

[0139] The branch distribution portions described in the embodiments can be variously combined as needed. For example, the orifice described in the third embodiment may be applied to the branch distribution portions in the other embodiments. Furthermore, the multi air conditioner for buildings has been described as an example of the refrigeration cycle apparatus. In addition to this, the present invention is also applicable to a refrigeration cycle apparatus such as, for example, a heat pump apparatus or a car air conditioner.

[0140] The embodiments disclosed herein are illustrative and non-restrictive. The present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

INDUSTRIAL APPLICABILITY

[0141] The present invention is effectively utilized in a refrigeration cycle apparatus including a heat exchanger.