JP2012207823A - Refrigerating cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely discharge a sufficient amount of refrigerant from a refrigerant storage by a refrigerating cycle device.SOLUTION: When the high-temperature and high-pressure refrigerant is supplied through a first refrigerant path 18 to a first heat exchanger, the first heat exchanger functions as a condenser. The refrigerant is returned to a compressor through a third refrigerant path 26. When the first refrigerant path 18 is cut off, the high-temperature and high-pressure refrigerant is supplied to a second heat exchanger through a second refrigerant path 25. The second heat exchanger functions as the condenser. When too much refrigerant is present on a circulation path, the refrigerant is stored into the refrigerant storage 60 through the first refrigerant path 18. When the refrigerant is insufficient on the circulation path, the refrigerant is discharged to the third refrigerant path 26 from the refrigerant storage 60. In discharge of the refrigerant, the high-temperature and high-pressure refrigerant is introduced into the refrigerant storage 60 through the second refrigerant path 25. The refrigerant is pushed out from within the refrigerant storage 60 under the action of high pressure.

Description

  The present invention relates to a refrigeration cycle apparatus used in, for example, an air conditioner.

  As described in Patent Document 1, an air conditioner including a plurality of outdoor units and a plurality of indoor units is widely known. During the cooling operation, the outdoor heat exchanger functions as a condenser. The indoor heat exchanger functions as an evaporator. The refrigerant flows from the indoor heat exchanger into the low pressure gas pipe. During heating operation, high-temperature and high-pressure refrigerant is supplied from the high-pressure gas pipe to the indoor heat exchanger. The refrigerant condensed in the indoor heat exchanger flows into the outdoor heat exchanger. The expansion valve and the outdoor heat exchanger are connected to each other by a liquid pipe.

  In such an air conditioner, adjustment of the refrigerant amount is required for operation. In adjusting the amount of refrigerant, a refrigerant reservoir is inserted between the liquid pipe and the low-pressure gas pipe. If it is determined that the refrigerant is excessively present in the circulation path, the refrigerant reservoir stores the refrigerant. When the refrigerant runs short in the circulation path, the refrigerant reservoir releases the refrigerant toward the circulation path. The storage and discharge of the refrigerant is controlled based on the degree of supercooling of the condenser.

JP 2008-185295 A

  In the above-described refrigerant reservoir, the refrigerant is discharged from the refrigerant reservoir to the circulation path based on the pressure difference between the pressure in the refrigerant reservoir and the pressure in the low-pressure gas pipe. As a result, for example, when the temperature of the outside air decreases, a sufficient pressure difference may not be ensured between the refrigerant reservoir and the low pressure gas pipe. In such a case, a sufficient amount of refrigerant may not be supplied to the low pressure gas pipe.

  According to some aspects of the present invention, a refrigeration cycle apparatus capable of reliably discharging a sufficient amount of refrigerant from a refrigerant reservoir can be provided.

  One form of the refrigeration cycle apparatus has a first heat exchanger between the compressor and the first expansion valve, and supply and shutoff of high-temperature and high-pressure refrigerant to the first heat exchanger is performed by the flow path switching means. A first refrigerant path formed between the compressor and the first heat exchanger is branched from the first refrigerant path at a first branch point to the first refrigerant path by the flow path switching unit. A second refrigerant path for supplying a high-temperature and high-pressure refrigerant to the second heat exchanger between the compressor and the first expansion valve when the high-temperature and high-pressure refrigerant is shut off; and the compressor and the second heat exchanger The refrigerant flowing out from the second heat exchanger when the refrigerant is branched from the second refrigerant path at the second branch point and supplied from the first refrigerant path to the first heat exchanger. A third refrigerant path leading to the suction side of the compressor, the first branch point and the first heat exchanger Branching from the first refrigerant path and connected to the suction side of the compressor, allowing the refrigerant to flow in from the first refrigerant path when the flow path switching means of the first refrigerant path is shut off, A fourth refrigerant path that blocks inflow of refrigerant from the first refrigerant path to the third refrigerant path when the refrigerant is supplied from the first refrigerant path to the first heat exchanger; and the first heat exchanger. And a refrigerant reservoir that acquires refrigerant from the first refrigerant path between the first expansion valve and discharges the refrigerant toward the third refrigerant path, and is connected to the second refrigerant path and the refrigerant reservoir. And a bypass path for introducing a high-temperature and high-pressure refrigerant from the second refrigerant path to the refrigerant reservoir.

  In such a refrigeration cycle apparatus, when a high-temperature and high-pressure refrigerant is supplied from the first refrigerant path to the first heat exchanger, the first heat exchanger functions as a condenser. The low-pressure gas-liquid two-phase refrigerant is supplied to the second heat exchanger. Thus, air is cooled in the second heat exchanger. The refrigerant is returned to the compressor from the third refrigerant path. A refrigerant circulation path is established by the first refrigerant path and the third refrigerant path.

  When the first refrigerant path is blocked, the high-temperature and high-pressure refrigerant is supplied from the second refrigerant path to the second heat exchanger. The second heat exchanger functions as a condenser. In the second heat exchanger, the air is warmed. The refrigerant is returned to the compressor from the first refrigerant path and the fourth refrigerant path. A refrigerant circulation path is established by the second refrigerant path, the first refrigerant path, and the fourth refrigerant path. Thus, cooling and heating are realized in the second heat exchanger in accordance with the switching of the first refrigerant path and the second refrigerant path.

  If excessive refrigerant exists in the circulation path, the refrigerant is stored in the refrigerant reservoir from the first refrigerant path. The amount of refrigerant in circulation is reduced. As a result, the liquid pool in the heat exchanger is eliminated. A decrease in heat exchange capacity is avoided. When the refrigerant runs short in the circulation path, the refrigerant is released from the refrigerant reservoir to the third refrigerant path. A sufficient amount of refrigerant is secured in the circulation path. A decrease in heat exchange capacity is avoided. At this time, high-temperature and high-pressure refrigerant is introduced into the refrigerant reservoir from the second refrigerant path when the refrigerant is released. Since the high pressure acts, the refrigerant is pushed out of the refrigerant reservoir. The refrigerant can be reliably discharged from the refrigerant reservoir.

  The refrigeration cycle apparatus includes a first release valve that is incorporated in the second refrigerant path between the bypass path and the second branch point, and switches between supply and shutoff of the refrigerant in the first refrigerant path, the compressor, A second opening valve may be provided that is incorporated in the third refrigerant path between the second branch points and that switches between the circulation and blocking of the refrigerant in the third refrigerant path. According to such an open valve, even when the high-temperature and high-pressure refrigerant is supplied from the first refrigerant path to the first heat exchanger, the high-temperature and high-pressure is supplied from the second refrigerant path to the second heat exchanger when the first refrigerant path is interrupted. Even when the refrigerant is supplied, the high-temperature and high-pressure refrigerant can always be supplied to the bypass path. The refrigerant can be reliably discharged from the refrigerant reservoir.

  The refrigeration cycle apparatus branches from the first refrigerant path between one or a plurality of second expansion valves, the first heat exchanger, and the first expansion valve, and each of the second expansion valves A first parallel refrigerant path individually connected to the first branch point and the second refrigerant path between the first branch point and the second branch point, and individually connected to each of the second expansion valves. Branch from the second parallel refrigerant path between the second parallel refrigerant path, the parallel second heat exchanger individually incorporated in each of the second parallel refrigerant paths, and the bypass path and the parallel second heat exchanger And a third parallel refrigerant path connected to the third refrigerant path.

  In such a refrigeration cycle apparatus, one or more parallel second heat exchangers are incorporated in parallel with the second heat exchanger. Cooling and heating can be realized with individual second heat exchangers and parallel second heat exchangers. In addition, when the second refrigerant path and the third refrigerant path are switched in the second heat exchanger, and the parallel second refrigerant path and the parallel third refrigerant path are switched for each parallel second heat exchanger, the second heat Cooling and heating can be mixed in the exchanger and the parallel second heat exchanger.

  In the refrigeration cycle apparatus, when at least one of the second heat exchanger and the parallel second heat exchanger functions as an evaporator, if the superheat degree of the evaporator is a predetermined value or more, the refrigerant reservoir A control circuit for generating a control signal for releasing the refrigerant from the refrigerant toward the third refrigerant path may be further provided.

  When the refrigerant is released from the refrigerant reservoir in this way, the shortage of refrigerant is eliminated in the evaporator. As a result, the heat exchange capacity of the evaporator can be increased. In the evaporator, the air is cooled efficiently. When cooling is realized by an evaporator, if the degree of superheat is not less than a predetermined value in the evaporator, the heat exchange capability of the evaporator will be reduced.

  In the refrigeration cycle apparatus, when all the second heat exchangers and the parallel second heat exchangers function as condensers, the refrigerant reservoir is such that the degree of superheat of the first heat exchanger is a predetermined value or more. A control circuit for generating a control signal for releasing the refrigerant from the refrigerant toward the third refrigerant path may be further provided.

  When the refrigerant is released from the refrigerant reservoir in this manner, the shortage of refrigerant is eliminated in the first heat exchanger. As a result, the heat exchange capacity of the first heat exchanger can be increased. Large heat energy can be imparted to the refrigerant in the first heat exchanger. Thermal energy can be efficiently released by the second heat exchanger or the parallel second heat exchanger. Efficient heating can be realized with the second heat exchanger or the parallel second heat exchanger.

  As described above, according to the present invention, a refrigeration cycle apparatus capable of reliably discharging a sufficient amount of refrigerant from a refrigerant reservoir is provided.

1 is a block diagram schematically showing a configuration of a refrigeration cycle apparatus, that is, an air conditioner according to a first embodiment of the present invention. It is a block diagram which shows the structure of a refrigerant | coolant storage unit roughly. It is a block diagram which shows roughly the control system of an air conditioner. FIG. 2 is a block diagram corresponding to FIG. 1 and showing a refrigerant flow when cooling operation is performed in all indoor units. FIG. 2 is a block diagram illustrating a refrigerant flow when heating operation is performed in all indoor units corresponding to FIG. 1. It is a block diagram which shows the flow of the refrigerant | coolant which implement | achieves cooling and heating simultaneous operation, when an outdoor unit functions as a condenser corresponding to FIG. It is a block diagram which shows the flow of the refrigerant | coolant which implement | achieves cooling and heating simultaneous operation, when an outdoor unit functions as an evaporator corresponding to FIG. It is a flowchart which shows the control method of a refrigerant | coolant storage unit roughly. It is a flowchart which shows the 1st discharge | release storage control roughly. It is a flowchart which shows the 2nd discharge storage control roughly. It is a flowchart which shows the 3rd discharge | release storage control roughly. 1 is a block diagram schematically showing a configuration of a refrigeration cycle apparatus, that is, an air conditioner according to a first embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 schematically shows the configuration of a refrigeration cycle apparatus, that is, an air conditioner 11 according to a first embodiment of the present invention. The air conditioner 11 includes one outdoor unit 12 and two indoor units 13a and 13b. The indoor units 13a and 13b are connected to the outdoor unit 12 in parallel with each other. The indoor units 13a and 13b may be installed in one room or may be installed individually in a plurality of rooms. In the air conditioner 11, operation and pause can be selected individually for each of the indoor units 13a and 13b. At the same time, in the air conditioner 11, the indoor unit 13a (13b) in the cooling operation and the indoor unit 13b (13a) in the heating operation can coexist as described later. 1, the air conditioner 11 may include two or more indoor units 13a, 13b,. Similarly, the indoor units 13a, 13b, etc. may be connected to the outdoor unit 12 in parallel.

  The air conditioner 11 includes a first heat exchanger, that is, an outdoor heat exchanger 14. The outdoor heat exchanger 14 is incorporated in the outdoor unit 12. The air conditioner 11 includes a plurality of indoor heat exchangers 15a and 15b. Here, for convenience, the first indoor heat exchanger 15a is a second heat exchanger, and the second indoor heat exchanger 15b is a first parallel second heat exchanger. The air conditioner 11 may include a plurality of parallel second heat exchangers, that is, third and subsequent indoor heat exchangers. All the indoor heat exchangers 15a and 15b should just have the same structure. The indoor heat exchangers 15a and 15b are individually incorporated into the individual indoor units 13a and 13b. The outdoor heat exchanger 14 and the indoor heat exchangers 15a and 15b realize exchange of heat energy between the refrigerant passing therethrough and ambient air.

  The air conditioner 11 includes a compressor 16. The compressor 16 is incorporated in the outdoor unit 12. The compressor 16 compresses the gas refrigerant. A high-pressure gas refrigerant is discharged from the compressor 16.

  The air conditioner 11 includes expansion valves 17a and 17b for each of the indoor heat exchangers 15a and 15b. The expansion valves 17a and 17b are individually incorporated in the individual indoor units 13a and 13b. A first refrigerant path 18 is formed between the compressor 16 and the expansion valve 17a. The outdoor heat exchanger 14 is incorporated in the first refrigerant path 18.

  Here, the first intermediate path 19 branches from the first refrigerant path 18. A branch point 21 between the first refrigerant path 18 and the first intermediate path 19 is disposed between the outdoor heat exchanger 14 and the expansion valve 17a. A first parallel refrigerant path 22 is connected to the first intermediate path 19. The first parallel refrigerant path 22 branches from the first intermediate path 19 at a branch point 23. The first parallel refrigerant path 22 is connected to the expansion valve 17b. Thus, the expansion valve 17b is connected to the outdoor heat exchanger 14 in parallel with the expansion valve 17a. Each time an indoor unit or an expansion valve is added to the air conditioner 11, the expansion valve may be individually connected to the first intermediate path 19 with a further first parallel refrigerant path (not shown). Thus, the first parallel refrigerant path branches off from the first refrigerant path 18 and is individually connected to each expansion valve.

  A second refrigerant path 25 branches from the first refrigerant path 18 at the branch point 24 between the compressor 16 and the outdoor heat exchanger 14. The branched second refrigerant path 25 is connected to the expansion valve 17a. An indoor heat exchanger 15 a is incorporated in the second refrigerant path 25.

  The third refrigerant path 26 branches from the second refrigerant path 25. The branch point 27 between the second refrigerant path 25 and the third refrigerant path 26 is between the compressor 16 and the indoor heat exchanger 15a, that is, the branch point 24 between the first refrigerant path 18 and the second refrigerant path 25 and the room heat. It arrange | positions between the exchangers 15a. The third refrigerant path 26 is connected to the suction side of the compressor 16.

  Here, the second intermediate path 28 branches from the second refrigerant path 25. A branch point 29 between the second refrigerant path 25 and the second intermediate path 28 is defined as a branch point 24 between the first refrigerant path 18 and the second refrigerant path 25 and a branch point 27 between the second refrigerant path 25 and the third refrigerant path 26. Arranged between. A second parallel refrigerant path 31 is connected to the second intermediate path 28. The second parallel refrigerant path 31 branches from the second intermediate path 28 at a branch point 32. The second parallel refrigerant path 31 is connected to the expansion valve 17b. The indoor heat exchanger 15 b is incorporated in the second parallel refrigerant path 31. Each time an indoor unit or expansion valve is added to the air conditioner 11, the expansion valve may be individually connected to the second intermediate path 28 by a further second parallel refrigerant path (not shown). Thus, the second parallel refrigerant paths 31 are individually branched from the second refrigerant path 25 and individually connected to the individual expansion valves.

  A third intermediate path 33 branches from the third refrigerant path 26. A branch point 34 between the third refrigerant path 26 and the third intermediate path 33 is disposed between the second refrigerant path 25 and the branch point 27 of the third refrigerant path 26 and the compressor 16. A third parallel refrigerant path 35 is connected to the third intermediate path 33. The third parallel refrigerant path 35 branches from the third intermediate path 33 at a branch point 36. The branched third parallel refrigerant path 35 is connected to the branch point 37 of the second parallel refrigerant path 31 between the indoor heat exchanger 15 b and the branch point 32. Each time an indoor unit, that is, an expansion valve is added to the air conditioner 11, a further third parallel refrigerant path (not shown) may be connected to the second parallel refrigerant path and the third intermediate path 33 individually. Thus, the third parallel refrigerant paths 35 are individually branched from the second parallel refrigerant paths 31 and connected to the third refrigerant path 26.

  A heating release valve 38 is incorporated in the second refrigerant path 25 between the branch point 27 of the second refrigerant path 25 and the third refrigerant path 26 and the branch point 29 of the second refrigerant path 25 and the second intermediate path 28. . The heating open valve 38 may be constituted by, for example, an electromagnetic open / close valve. The heating opening valve 38 allows the refrigerant to flow through the second refrigerant path 25 when the valve is opened, while blocking the refrigerant flowing through the second refrigerant path 25 when the valve is closed.

  Similarly, the second parallel refrigerant path 31 is heated between the branch point 32 of the second intermediate path 28 and the second parallel refrigerant path 31 and the branch point 37 of the second parallel refrigerant path 31 and the third parallel refrigerant path 35. An hour opening valve 39 is incorporated. Similarly, the heating release valve 39 may be constituted by an electromagnetic on-off valve, for example. The heating open valve 39 allows the refrigerant to flow through the second parallel refrigerant path 31 when the valve is opened, while blocking the refrigerant flow through the second parallel refrigerant path 31 when the valve is closed. The heating release valve 39 may be incorporated into the second parallel refrigerant path for each expansion valve each time an indoor unit, that is, an expansion valve, is added to the air conditioner 11.

  A cooling release valve 41 is incorporated in the third refrigerant path 26 between the branch point 27 of the second refrigerant path 25 and the third refrigerant path 26 and the branch point 34 of the third refrigerant path 26 and the third intermediate path 33. . The cooling opening valve 41 may be constituted by, for example, an electromagnetic opening / closing valve. The cooling opening valve 41 allows the refrigerant to flow through the third refrigerant path 26 when the valve is opened, and blocks the refrigerant flow through the third refrigerant path 26 when the valve is closed. Here, the branch point 27, the heating opening valve 38, and the cooling opening valve 41 may be incorporated in the indoor unit 13a, and may be configured separately from the outdoor unit 12 and the indoor units 13a, 13b as branch units. .

  Similarly, the third parallel refrigerant path 35 is cooled between the branch point 37 of the second parallel refrigerant path 31 and the third parallel refrigerant path 35 and the branch point 36 of the third intermediate path 33 and the third parallel refrigerant path 35. An hour open valve 42 is incorporated. The cooling opening valve 42 may be constituted by an electromagnetic opening / closing valve, for example. The cooling open valve 42 allows the refrigerant to flow through the third parallel refrigerant path 35 when the valve is opened, while blocking the refrigerant flow through the third parallel refrigerant path 35 when the valve is closed. The cooling-time release valve 42 may be incorporated into a further third parallel refrigerant path for each expansion valve every time an indoor unit, that is, an expansion valve is added to the air conditioner 11. Here, the branch point 37, the heating opening valve 39, and the cooling opening valve 42 may be incorporated in the indoor unit 13b, and may be configured separately from the outdoor unit 12 and the indoor units 13a, 13b as branch units. .

  A four-way valve 43 is inserted into the first refrigerant path 18 between the branch point 24 of the first refrigerant path 18 and the second refrigerant path 25 and the outdoor heat exchanger 14. The four-way valve 43 is switched between the first position and the second position. The four-way valve 43 in the first position establishes a path that connects the first port 44a and the second port 44b to each other and a path that connects the third port 44c and the fourth port 44d to each other. The four-way valve 43 in the second position establishes a path that connects the first port 44a and the fourth port 44d to each other and a path that connects the second port 44b and the third port 44c to each other.

  A fourth refrigerant path 45 is formed between the third port 44 c and the fourth port 44 d and the third refrigerant path 26. The fourth refrigerant path 45 includes a first flow path 45a and a second flow path 45b. The first flow passage 45 a connects the third port 44 c of the four-way valve 43 and the third refrigerant path 26. The second flow path 45b connects the fourth port 44d of the four-way valve 43 and the third refrigerant path 26 or the first flow path 45a. For example, a capillary tube 46 is inserted into the second flow passage 45b. The capillary tube 46 restricts the circulation of the refrigerant.

  An accumulator 47 is incorporated in the third refrigerant path 26 between the fourth refrigerant path 45 and the compressor 16. The accumulator 47 can separate the gas refrigerant and the liquid refrigerant and prevent the liquid from returning to the compressor 16.

  An outdoor unit expansion valve 48 is further incorporated in the first refrigerant path 18. The outdoor unit expansion valve 48 is disposed between the outdoor heat exchanger 14 and the branch point 21. The flow rate of the refrigerant is adjusted according to the opening degree of the outdoor unit expansion valve 48.

  Two pressure sensors 49 and 51 are associated with the compressor 16. The first pressure sensor 49 measures the refrigerant pressure on the discharge side of the compressor 16. For example, the pressure sensor 49 is attached to the second refrigerant path 25 between the branch point 24 of the first refrigerant path 18 and the second refrigerant path 25 and the branch point 29 of the second refrigerant path 25 and the second intermediate path 28. The pressure sensor 49 measures the pressure of the refrigerant in the second refrigerant path 25. The second pressure sensor 51 measures the refrigerant pressure on the suction side of the compressor 16. For example, the pressure sensor 51 is attached to the third refrigerant path 26 between the fourth refrigerant path 45 and the compressor 16. The pressure sensor 51 measures the pressure of the refrigerant in the third refrigerant path 26.

  Three temperature sensors 52, 53, 54 are associated with the outdoor heat exchanger 14. The first temperature sensor 52 measures the temperature of the refrigerant at the outlet of the outdoor heat exchanger 14 when the outdoor heat exchanger 14 functions as a condenser. That is, the temperature sensor 52 is attached to the first refrigerant path 18 at the outlet of the outdoor heat exchanger 14. The second temperature sensor 53 measures the temperature of the refrigerant downstream of the outdoor unit expansion valve 48 when the outdoor heat exchanger 14 functions as a condenser. That is, the temperature sensor 53 is attached to the first refrigerant path 18 downstream of the outdoor unit expansion valve 48. Further, the third temperature sensor 54 measures the temperature of the refrigerant at the outlet of the outdoor heat exchanger 14 when the outdoor heat exchanger 14 functions as an evaporator. That is, the temperature sensor 54 is attached to the first refrigerant path 18 at the outlet of the outdoor heat exchanger 14.

  Two temperature sensors 55 and 56 are associated with the indoor heat exchanger 15a. The first temperature sensor 55 measures the refrigerant temperature at the outlet of the indoor heat exchanger 15a when the indoor heat exchanger 15a functions as a condenser. That is, the temperature sensor 55 is attached to the second refrigerant path 25 at the outlet of the indoor heat exchanger 15a. The second temperature sensor 56 measures the temperature of the refrigerant at the outlet of the indoor heat exchanger 15a when the indoor heat exchanger 15a functions as an evaporator. That is, the temperature sensor 56 is attached to the second refrigerant path 25 at the outlet of the indoor heat exchanger 15a.

  Similarly, two temperature sensors 57 and 58 are associated with the indoor heat exchanger 15b. The first temperature sensor 57 measures the temperature of the refrigerant at the outlet of the indoor heat exchanger 15b when the indoor heat exchanger 15b functions as a condenser. That is, the temperature sensor 57 is attached to the second parallel refrigerant path 31 at the outlet of the indoor heat exchanger 15b. The second temperature sensor 58 measures the temperature of the refrigerant at the outlet of the indoor heat exchanger 15b when the indoor heat exchanger 15b functions as an evaporator. That is, the temperature sensor 58 is attached to the second parallel refrigerant path 31 at the outlet of the indoor heat exchanger 15b. The temperature sensors 57 and 58 should just be attached to the further 2nd parallel refrigerant path for every indoor heat exchanger, whenever an indoor unit, ie, an indoor heat exchanger, is added to the air conditioner 11. FIG.

  The air conditioner 11 includes a refrigerant storage unit 59. The refrigerant storage unit 59 is incorporated in the outdoor unit 12. As shown in FIG. 2, the refrigerant storage unit 59 includes a refrigerant reservoir 60. A storage space 61 is formed in the refrigerant reservoir 60. In the storage space 61, the gas refrigerant and the liquid refrigerant are separated by the action of gravity. Liquid refrigerant accumulates downward.

  The refrigerant reservoir 60 is connected to the first refrigerant path 18 by an inflow path 62. The inflow path 62 is connected to the first refrigerant path 18 between the branch point 21 of the first refrigerant path 18 and the first intermediate path 19 and the outdoor heat exchanger 14. A strainer 63, a first on-off valve 64, and a check valve 65 are incorporated in the inflow path 62. The strainer 63 removes foreign matters in the refrigerant. For example, an electromagnetic on-off valve may be used as the first on-off valve 64. When the first on-off valve 64 is opened, the liquid refrigerant flows from the first refrigerant path 18 into the storage space 61 according to the pressure difference between the pressure in the first refrigerant path 18 and the pressure in the storage space 61. The check valve 65 prevents the refrigerant from flowing backward from the storage space 61 toward the first refrigerant path 18.

  The refrigerant reservoir 60 is connected to the third refrigerant path 26 by an outflow path 66. The outflow path 66 is connected to the third refrigerant path 26 between the branch point 34 of the third refrigerant path 26 and the third intermediate path 33 and the compressor 16. In the outflow path 66, a strainer 67, a second on-off valve 68, and a decompressor 69 are incorporated. As the second on-off valve 68, for example, an electromagnetic on-off valve is used. For example, a capillary tube may be used as the decompressor 69. When the second on-off valve 68 is opened, the refrigerant flows from the storage space 61 to the third refrigerant path 26 according to the pressure difference between the pressure in the storage space 61 and the pressure of the third refrigerant path 26. At this time, the refrigerant is gasified by the action of the decompressor 69. A gas refrigerant is introduced into the third refrigerant path 26. The strainer 67 removes foreign matters in the refrigerant.

  An auxiliary path 71 for venting gas is connected to the refrigerant reservoir 60. The auxiliary path 71 is opened at the upper part of the storage space 61 as much as possible. The auxiliary path 71 is connected to the third refrigerant path 26. A strainer 72 and a third on-off valve 73 are incorporated in the auxiliary path 71. As the third on-off valve 73, for example, an electromagnetic on-off valve is used. When the third on-off valve 73 is opened, the gas refrigerant can escape from the storage space 61 to the third refrigerant path 26 through the auxiliary path 71 instead of the liquid refrigerant taken in from the inflow path 62.

  A bypass path 74 is connected to the refrigerant reservoir 60. The bypass path 74 is connected to the second refrigerant path 25 between the branch point 24 of the first refrigerant path 18 and the second refrigerant path 25 and the branch point 29 of the second refrigerant path 25 and the second intermediate path 28. A strainer 75, a fourth on-off valve 76, and a check valve 77 are incorporated in the bypass path 74. The strainer 75 removes foreign matters in the refrigerant. When the fourth on-off valve 76 is opened, the high-temperature and high-pressure refrigerant flows into the storage space 61 from the second refrigerant path 25. The check valve 77 prevents the refrigerant from flowing backward from the storage space 61 toward the second refrigerant path 25.

  FIG. 3 schematically shows a control system of the air conditioner 11. The air conditioner 11 includes a control circuit 81. This control circuit 81 is incorporated in the outdoor unit 12, for example. The compressor 16, the four-way valve 43, the outdoor unit expansion valve 48, the first on-off valve 64, the second on-off valve 68, the third on-off valve 73, and the fourth on-off valve 76 in the outdoor unit 12 are connected to the control circuit 81, respectively. Is done. The control circuit 81 supplies control signals to the compressor 16, the four-way valve 43, the outdoor unit expansion valve 48, the first on-off valve 64, the second on-off valve 68, the third on-off valve 73, and the fourth on-off valve 76, respectively. Depending on the control signal, the on / off of the compressor 16 and the rotational speed are controlled. In response to the control signal, the four-way valve 43 is switched between the first position and the second position. The opening degree of the outdoor unit expansion valve 48 is controlled according to the control signal. In response to the control signal, the first on-off valve 64, the second on-off valve 68, the third on-off valve 73, and the fourth on-off valve 76 are switched between opening and closing.

  In addition, the control circuit 81 is connected to the expansion valve 17a of the indoor unit 15a, the heating release valve 38, and the cooling release valve 41, and the expansion valve 17b, the heating release valve 39, and the cooling release valve 42 of the indoor unit 15b. Connected. The control circuit 81 supplies control signals to the expansion valve 17a, the heating release valve 38, the cooling release valve 41, the expansion valve 17b, the heating release valve 39, and the cooling release valve 42, respectively. The opening degree of the expansion valves 17a and 17b is controlled according to the control signal. The opening may be set by the number of pulses of the built-in stepping motor, for example. In response to the control signal, the heating open valve 38, the cooling open valve 41, the heating open valve 39, and the cooling open valve 42 are switched between open and closed.

  Further, pressure sensors 49 and 51, temperature sensors 52, 53 and 54 and an opening degree sensor 82 of the outdoor unit 12 are connected to the control circuit 81. The pressure sensors 49 and 51 supply a pressure information signal to the control circuit 81. The pressure information signal specifies the pressure value of the refrigerant. The control circuit 81 calculates a high-pressure saturation temperature based on the pressure information signal from the pressure sensor 49. The high-pressure saturation temperature corresponds to the refrigerant temperature in the outdoor heat exchanger 14 when the outdoor heat exchanger 14 functions as a condenser. Similarly, the control circuit 81 calculates a low pressure saturation temperature based on the pressure information signal of the pressure sensor 51. The low-pressure saturation temperature corresponds to the refrigerant temperature in the outdoor heat exchanger 14 when the outdoor heat exchanger 14 functions as an evaporator. The temperature sensors 52, 53, and 54 supply temperature information signals to the control circuit 81. The temperature information signal specifies the temperature value of the refrigerant. The opening sensor 82 supplies an opening information signal to the control circuit 81. The opening degree information signal specifies the opening degree of the outdoor unit expansion valve 48.

  Furthermore, the opening degree sensor 83 and temperature sensors 55 and 56 of the indoor unit 13a and the opening degree sensor 84 and temperature sensors 57 and 58 of the indoor unit 13b are connected to the control circuit 81. The temperature sensors 55, 56, 57 and 58 supply temperature information signals to the control circuit 81. The temperature information signal specifies the temperature value of the refrigerant. The opening sensors 83 and 84 measure the opening degrees of the corresponding expansion valves 17a and 17b, respectively. The opening sensors 83 and 84 supply an opening information signal to the control circuit 81. The opening degree information signal specifies the opening degree of the expansion valves 17a and 17b.

  Next, the operation of the air conditioner 11 will be briefly described. Here, although the case where two indoor units 13a and 13b are incorporated in the air conditioner 11 according to the present embodiment will be described in detail, the air conditioner 11 includes three or more indoor units 13a as described above. , 13b... Can be incorporated. Therefore, in the following, for convenience of explanation, three or more indoor units 13a, 13b,... Are also assumed, and the two indoor units 13a, 13b are referred to as “all” indoor units 13a, 13b.

  Now, it is assumed that the cooling operation is performed in all the indoor units 13a and 13b. As shown in FIG. 4, the control circuit 81 sets the four-way valve 43 at the first position. As a result, the first refrigerant path 18 is opened from the compressor 16 to the expansion valve 17a. In addition, the first refrigerant path 18, the first intermediate path 19, and the first parallel refrigerant path 22 are opened from the compressor 16 to the expansion valve 17b. In the fourth refrigerant path 45, no refrigerant flows from the first refrigerant path 18.

  At the same time, the control circuit 81 closes the heating opening valves 38 and 39 and opens the cooling opening valves 41 and 42. As a result, a circulation path from the expansion valve 17a through the second refrigerant path 25 to the third refrigerant path 26 is established. At the same time, a circulation path is established from the expansion valve 17b to the third refrigerant path 26 through the second parallel refrigerant path 31, the third parallel refrigerant path 35, and the third intermediate path 33. In the fourth refrigerant path 45, the refrigerant from the third refrigerant path 26 does not flow.

  The control circuit 81 controls the operation of the compressor 16. High-temperature and high-pressure refrigerant flows through the first refrigerant path 18, the first intermediate path 19 and the first parallel refrigerant path 22 between the compressor 16 and the expansion valves 17a and 17b. At the same time, high-temperature and high-pressure refrigerant flows through the second refrigerant path 25, the second intermediate path 28, and the second parallel refrigerant path 31 between the compressor 16 and the heating release valves 38 and 39. In this way, the high-temperature and high-pressure refrigerant is supplied to the outdoor heat exchanger 14. The outdoor heat exchanger 14 functions as a condenser. The condensed liquid refrigerant is decompressed by the expansion valves 17a and 17b, and then passes through the indoor heat exchangers 15a and 15b. The indoor heat exchangers 15a and 15b function as an evaporator. As a result, the indoor air is cooled.

  Then, the scene where heating operation is implemented by all the indoor units 13a and 13b is assumed. As shown in FIG. 5, the control circuit 81 sets the four-way valve 43 at the second position. As a result, the first refrigerant path 18 is blocked between the compressor 16 and the outdoor heat exchanger 14. At the same time, the first refrigerant path 18 and the fourth refrigerant path 45 are connected to each other.

  In addition, the control circuit 81 opens the heating opening valves 38 and 39 and closes the cooling opening valves 41 and 42. As a result, the refrigerant flow is blocked between the second refrigerant path 25 and the third refrigerant path 26, and the refrigerant flow is blocked between the second parallel refrigerant path 31 and the third parallel refrigerant path 35. A refrigerant path from the branch point 22 through the second refrigerant path 25 to the expansion valve 17a is established, and the expansion valve from the branch point 22 through the second refrigerant path 25, the second intermediate path 28, and the second parallel refrigerant path 31. A circulation path to 17b is established.

  When the high-temperature and high-pressure refrigerant is discharged from the compressor 16, the high-temperature and high-pressure refrigerant flows into the second refrigerant path 25, the second intermediate path 28, and the second parallel refrigerant path 31 between the compressor 16 and the expansion valves 17a and 17b. Circulate. At the same time, high-temperature and high-pressure refrigerant flows through the first refrigerant path 18 and the fourth refrigerant path 45 between the compressor 16 and the capillary tube 46. Thus, the high-temperature and high-pressure refrigerant is supplied to the indoor heat exchangers 15a and 15b. The indoor heat exchangers 15a and 15b function as condensers. As a result, the indoor air is warmed. The condensed refrigerant is decompressed by the expansion valves 17a and 17b and then passes through the outdoor heat exchanger 14. The outdoor heat exchanger 14 functions as an evaporator. The fourth refrigerant path 45 allows the refrigerant to flow from the first refrigerant path 18.

  Next, assume that when the outdoor heat exchanger 14 functions as a condenser, a cooling operation is performed in the indoor unit 13a and a heating operation is performed in the indoor unit 13b. As shown in FIG. 6, the control circuit 81 sets the four-way valve 43 at the first position. At the same time, the control circuit 81 closes the heating release valve 38 and the cooling release valve 42 and opens the cooling release valve 41 and the heating release valve 39. As a result, a circulation path is established in the first refrigerant path 18 between the compressor 16 and the expansion valve 17a. On the other hand, a circulation path is established between the compressor 16 and the expansion valve 17b by the second refrigerant path 25, the second intermediate path 28, and the second parallel refrigerant path 31. The refrigerant condensed in the indoor heat exchanger 15b is supplied to the indoor heat exchanger 15a through the first parallel refrigerant path 22, the first intermediate path 19, and the first refrigerant path 18. Thus, the indoor unit 13a for cooling operation and the indoor unit 13b for heating operation can coexist with one outdoor unit 12. Such cooling and heating simultaneous operation is assumed to be used in a situation where, for example, a living space is heated in one building and a computer server room is cooled. At this time, since the branch point 29 of the second refrigerant path 25 and the second intermediate path 28 is disposed between the compressor 16 and the heating release valve 38, the heating release valve 38 acts on the expansion valve 17 a. Even when the high-temperature and high-pressure refrigerant is blocked in the first refrigerant path 18, the high-temperature and high-pressure refrigerant can be reliably supplied to the expansion valve 17 b from the second refrigerant path 25. Here, the control circuit 81 controls the flow rate of the refrigerant flowing into the outdoor heat exchanger 14. Such control of the flow rate is realized by the action of the outdoor unit expansion valve 48. For example, the control circuit 81 controls the opening degree of the outdoor unit expansion valve 48 so as to maintain a constant pressure difference between the pressure value of the pressure sensor 49 and the pressure value downstream of the outdoor unit expansion valve 48.

  Further, assume that when the outdoor heat exchanger 14 functions as an evaporator, a cooling operation is performed in the indoor unit 13a and a heating operation is performed in the indoor unit 13b. As shown in FIG. 7, the control circuit 81 sets the four-way valve 43 at the second position. At the same time, the control circuit 81 closes the heating release valve 38 and the cooling release valve 42 and opens the cooling release valve 41 and the heating release valve 39. As a result, a circulation path is established between the compressor 16 and the expansion valve 17b by the second refrigerant path 25, the second intermediate path 28, and the second parallel refrigerant path 31. The refrigerant condensed in the indoor heat exchanger 15 b is supplied to the outdoor heat exchanger 14 through the first parallel refrigerant path 22, the first intermediate path 19 and the first refrigerant path 18. At the same time, the refrigerant condensed in the indoor heat exchanger 15 b is supplied to the indoor heat exchanger 15 a via the first parallel refrigerant path 22, the first intermediate path 19 and the first refrigerant path 18. Thus, the indoor unit 13a for cooling operation and the indoor unit 13b for heating operation can coexist with one outdoor unit 12. The control circuit 81 controls the flow rate of the refrigerant flowing into the outdoor heat exchanger 14. Such control of the flow rate is realized by the action of the outdoor unit expansion valve 48. For example, the control circuit 81 controls the opening degree of the outdoor unit expansion valve 48 so as to maintain a constant temperature difference between the low pressure saturation temperature and the temperature detected by the temperature sensor 54 from the refrigerant pressure detected by the pressure sensor 51. To do.

  In switching the four-way valve 43, the control circuit 81 compares the cooling load of the indoor unit 13a (or 13b) with the heating load of the indoor unit 13b (13a). If the cooling load is larger than the heating load, the control circuit 81 sets the four-way valve 43 at the first position. At this time, the outdoor heat exchanger 14 functions as a condenser. On the other hand, if the heating load is larger than the cooling load, the control circuit 81 sets the four-way valve 43 at the second position. At this time, the outdoor heat exchanger 14 functions as an evaporator. In particular, when three or more indoor units 13a, 13b ... are incorporated in the air conditioner 11, the entire cooling load of the indoor units 13a, 13b ... during the cooling operation and the indoor units 13a, 13b ... during the heating operation What is necessary is just to compare with the whole heating load.

  Next, operation | movement of the refrigerant | coolant storage unit 59 is demonstrated, referring the flowchart of FIGS. As shown in FIG. 8, in step S1, the control circuit 81 determines the presence or absence of the heating operation. When it is determined that the “operating” indoor units 13a and 13b are not included in the heating operation, in other words, all the “operating” indoor units 13a and 13b are determined to be in the cooling operation. The processing operation of the circuit 81 proceeds to step S2. In step S2, the control circuit 81 performs “first release storage control”. The control circuit 81 adjusts the amount of refrigerant in the circulation path based on the release and storage of the refrigerant. In carrying out the “first release storage control”, the control circuit 81 monitors the amount of refrigerant in the circulation path. If it is determined that the amount of refrigerant in the circulation path is excessive in the entire air conditioner 11, the refrigerant storage unit 59 stores the refrigerant from the circulation path. The refrigerant pool is eliminated by the heat exchanger according to the storage of the refrigerant. When liquid refrigerant accumulates in the heat exchanger, the heat exchange area is reduced at the liquid refrigerant storage portion. As a result, the heat exchange capacity of the heat exchanger decreases. Conversely, if it is determined that the amount of refrigerant in the circulation path is insufficient in the entire air conditioner 11, the refrigerant storage unit 59 releases the refrigerant to the circulation path. If the refrigerant runs short, the heat exchange capability of the heat exchanger will be reduced. When the “first release storage control” is completed, the processing operation of the control circuit 81 returns to step S1.

  If at least one heating operation is performed in step S1, the processing operation of the control circuit 81 proceeds to step S3. In step S3, it is determined whether or not the indoor units 13a and 13b that are in operation include those that are in the cooling operation. If all indoor units 13a and 13b that are “operating” are in heating operation, the processing operation of the control circuit 81 proceeds to step S4. In step S4, “second release storage control” is performed. Similarly, the control circuit 81 adjusts the amount of refrigerant in the circulation path based on the release and storage of the refrigerant. When the “second release storage control” is completed, the processing operation of the control circuit 81 returns to step S1. On the other hand, if it is determined in step S3 that at least one unit is performing the cooling operation, the control circuit 81 performs “third release storage control” in step S5. Similarly, the control circuit 81 adjusts the amount of refrigerant in the circulation path based on the release and storage of the refrigerant. When the “third release storage control” ends, the processing operation of the control circuit 81 returns to step S1.

  As shown in FIG. 9, the control circuit 81 identifies the degree of superheat of the indoor heat exchangers 15 a and 15 b in step T <b> 1 when performing the “first release storage control”. In specifying the degree of superheat, the control circuit 81 subtracts the inlet temperature from the outlet temperature of the indoor heat exchangers 15a and 15b functioning as an evaporator. The outlet temperature is specified by temperature information signals from the temperature sensors 56 and 58. The inlet temperature is specified by the temperature information signal from the temperature sensors 55 and 57. The degree of superheat of the indoor heat exchangers 15a and 15b is specified by subtracting the temperature values of the temperature sensors 55 and 57 from the temperature values of the temperature sensors 56 and 58. If the degree of superheat is, for example, a predetermined value or more (for example, 10 degrees or more), the control circuit 81 specifies the opening degree of the expansion valves 17a, 17b of the indoor units 13a, 13b in step T2. In specifying the opening, the control circuit 81 acquires an opening information signal from the opening sensors 83 and 84. If the expansion valves 17a and 17b are fully open, the control circuit 81 releases the refrigerant from the refrigerant reservoir 60 in step T3. In discharging, the control circuit 81 opens the second on-off valve 68 and the fourth on-off valve 76. As a result, the refrigerant flows from the outflow path 66 into the third refrigerant path 26. When flowing in, the decompressor 69 vaporizes the refrigerant. The control circuit 81 ends the discharge of the refrigerant in step T4 after 10 seconds have elapsed from the start of the discharge. The process ends. If the opening degree of the expansion valves 18a, 18b is other than full open in step T2, the control circuit 81 ends the process. Here, if either one of the indoor heat exchangers 15a and 15b has a superheat degree equal to or greater than a predetermined value and the corresponding expansion valves 17a, 17b.

  If the degree of superheat is less than the predetermined value in any of the indoor heat exchangers 15a and 15b in step T1, the control circuit 81 specifies the degree of supercooling of the outdoor heat exchanger 14 in step T5. In specifying the degree of supercooling, the control circuit 81 acquires a pressure information signal from the pressure sensor 49 and acquires a temperature information signal from the temperature sensor 52. The control circuit 81 calculates a high pressure saturation temperature from the pressure information signal. The high-pressure saturation temperature corresponds to the refrigerant temperature in the outdoor heat exchanger 14 that functions as a condenser. By subtracting the temperature value of the temperature information signal from the temperature value of the high-pressure saturation temperature, the degree of supercooling of the outdoor heat exchanger 14 functioning as a condenser is specified. If the degree of supercooling is, for example, a predetermined value or more (for example, 7 degrees or more), the control circuit 81 stores the refrigerant in the refrigerant reservoir 60 in step T6. The control circuit 81 opens the first on-off valve 64 and the third on-off valve 73. As a result, the refrigerant flows from the first refrigerant path 18 into the refrigerant reservoir 60. At this time, since the gas refrigerant in the storage space 61 is released to the third refrigerant path 26, the refrigerant surely flows from the inflow path 62. The control circuit 81 ends the storage of the refrigerant in step T7 after 10 seconds have elapsed from the start of the storage. The process ends. If the degree of supercooling is less than the predetermined value in step T5, the process ends.

  As shown in FIG. 10, the control circuit 81 specifies the degree of superheat of the outdoor heat exchanger 14 in step V <b> 1 when performing the “second release storage control”. In specifying the degree of superheat, the control circuit 81 acquires a pressure information signal from the pressure sensor 51 and acquires a temperature information signal from the temperature sensor 54. The control circuit 81 calculates a low pressure saturation temperature from the pressure information signal. By subtracting the temperature value of the low-pressure saturation temperature from the temperature value of the temperature information signal, the degree of superheat of the outdoor heat exchanger 14 functioning as an evaporator is specified. If the degree of superheat is, for example, a predetermined value or more (for example, 10 degrees or more), the control circuit 81 specifies the opening degree of the outdoor unit expansion valve 48 in step V2. In specifying the opening, the control circuit 81 acquires an opening information signal from the opening sensor 82. If the outdoor unit expansion valve 48 is fully open, the control circuit 81 releases the refrigerant from the refrigerant reservoir 60 in step V3 as described above. The control circuit 81 ends the discharge of the refrigerant in step V4 after 10 seconds have elapsed from the start of the discharge. The process ends. If the opening degree of the outdoor unit expansion valve 48 is other than fully open in step V2, the control circuit 81 ends the process.

  If the degree of superheat of the outdoor heat exchanger 14 is less than a predetermined value in step V1, the control circuit 81 specifies the degree of supercooling of the indoor heat exchangers 15a and 15b functioning as condensers in step V5. In specifying the degree of supercooling, the control circuit 81 acquires a pressure information signal from the pressure sensor 49 and acquires temperature information signals from the temperature sensors 55 and 57 of the indoor units 13a and 13b. The control circuit 81 calculates a high pressure saturation temperature from the pressure information signal. By subtracting the temperature value of the temperature information signal from the temperature value of the high-pressure saturation temperature, the degree of supercooling of the indoor heat exchangers 15a and 15b functioning as condensers is specified. If the degree of supercooling is, for example, a predetermined value or more (for example, 7 degrees or more), the control circuit 81 stores the refrigerant in the refrigerant reservoir 60 in step V6 as described above. The control circuit 81 ends the storage of the refrigerant in Step V7 after 10 seconds have elapsed from the start of the storage. The process ends. If the degree of supercooling is less than the predetermined value in step V5, the process ends. Here, the control circuit 81 uses the average value of the degree of supercooling when determining the storage.

  In performing the “third release storage control”, in step W1, the control circuit 81 specifies the degree of superheat of the indoor heat exchanger 15a (15b) functioning as an evaporator. In specifying the degree of superheat, the control circuit 81 subtracts the inlet temperature from the outlet temperature of the indoor heat exchanger 15a (15b) as described above. If the degree of superheat is, for example, a predetermined value or more (for example, 10 degrees or more), the control circuit 81 specifies the opening degree of the expansion valve 17a (17b) of the indoor unit 13a (13b) in step W2. If the expansion valve 17a (17b) is fully open, the control circuit 81 releases the refrigerant from the refrigerant reservoir 60 in step W3 as described above. The control circuit 81 ends the discharge of the refrigerant in step W4 after 10 seconds have elapsed from the start of the discharge. The process ends. If the opening degree of the outdoor unit expansion valve 48 is other than full open in step W2, the control circuit 81 ends the process.

  If the superheat degree of the indoor heat exchanger 15a (15b) is less than a predetermined value in step W1, the control circuit 81 specifies the supercooling degree of the indoor heat exchanger 15b (15a) functioning as a condenser in step W5. If the degree of supercooling is, for example, a predetermined value or more (for example, 7 degrees or more), the control circuit 81 stores the refrigerant in the refrigerant reservoir 60 in step W6. The control circuit 81 ends the storage of the refrigerant in step W7 after 10 seconds have elapsed from the start of the storage. The process ends. If the degree of supercooling is less than the predetermined value in step W5, the process ends.

  In the air conditioner 11, the fourth on-off valve 76 is opened in the bypass path 74 when the refrigerant is discharged from the refrigerant reservoir 60. Accordingly, the high-temperature and high-pressure refrigerant is introduced into the refrigerant reservoir 60 from the second refrigerant path 25 through the bypass path 74. The refrigerant is pushed out from the refrigerant reservoir 60 to the outflow path 66 by the action of the refrigerant. As a result, the air conditioner 11 can reliably release the refrigerant from the refrigerant reservoir 60.

  FIG. 12 schematically shows the configuration of a refrigeration cycle apparatus, that is, an air conditioner 11a according to a second embodiment of the present invention. The air conditioner 11a includes two outdoor units 12a and 12b and two indoor units 13a and 13b. The outdoor units 12a and 12b have the same structure as the outdoor unit 12. In addition, the same reference numerals are assigned to components equivalent to those of the air conditioner 11 according to the first embodiment. As is clear from FIG. 12, the air conditioner 11 may include two or more outdoor units 12a, 12b, and may include two or more indoor units 13a, 13b, and so on. The outdoor units 12a, 12b,... Need only be connected in parallel to the indoor units 13a, 13b, and the indoor units 13a, 13b, etc. can be connected in parallel to the outdoor units 12a, 12b,. Good.

  The first refrigerant paths 18 of the outdoor units 12a and 12b are connected to each other. That is, the first refrigerant path 18 of the outdoor unit 12 b is connected to the first intermediate path 19. The first intermediate path 19 functions as a connection path common to further outdoor units and further indoor units.

  The second refrigerant paths 25 of the outdoor units 12a and 12b are connected to each other. That is, the second refrigerant path 25 of the outdoor unit 12 b is connected to the second intermediate path 28. The second intermediate path 28 functions as a connection path common to further outdoor units and further indoor units.

  The third refrigerant paths 26 of the outdoor units 12a and 12b are connected to each other. That is, the third refrigerant path 26 of the outdoor unit 12 b is connected to the third intermediate path 33. The third intermediate path 33 functions as a connection path common to further outdoor units and further indoor units.

  The refrigerant storage unit 59 of the outdoor units 12a and 12b is controlled based on the control circuit 81 of the outdoor unit 12a. The control circuit 81 executes processing according to the flowcharts of FIGS. In storing the refrigerant, the control circuit 81 opens the first on-off valve 64 and the third on-off valve 73 of the outdoor units 12a, 12b. In determining the storage, the control circuit 81 uses the average value of the degree of supercooling of the outdoor heat exchanger 14 during operation. When stopping the storage, the control circuit 81 closes the first on-off valve 64 and the third on-off valve 73 of the outdoor units 12a and 12b. In releasing the refrigerant, the control circuit 81 opens the second on-off valve 68 and the fourth on-off valve 76 of the outdoor units 12a, 12b. If at least one of the plurality of outdoor heat exchangers 14 satisfies the predetermined conditions for the degree of superheat and the opening degree of the expansion valve, the control circuit 81 releases the refrigerant. When stopping the release, the control circuit 81 closes the second on-off valve 68 and the fourth on-off valve 76 of the outdoor units 12a, 12b.

  When three or more indoor units 13a, 13b,... Are incorporated in the air conditioners 11, 11a, when the cooling operation is performed in all the indoor units 13a, 13b, the “first release storage control” is performed. When one of the plurality of indoor heat exchangers 15a, 15b,... Has a degree of superheat above a predetermined value and the corresponding expansion valves 17a, 17b,. Similarly, when the heating operation is performed in all the indoor units 13a, 13b..., An average value is calculated from the degree of supercooling of all the indoor heat exchangers 15a, 15b. When the cooling operation and the heating operation are mixed, in the “third release storage control”, at least one of the indoor heat exchangers 15a, 15b... Functioning as an evaporator has a degree of superheat of a predetermined value or more and the corresponding expansion valve 17a. , 17b ... are fully opened, the refrigerant is released, and if the average value of the degree of subcooling of the indoor heat exchangers 15a, 15b ... functioning as condensers is equal to or greater than a predetermined value, the refrigerant is stored.

  11 cycle device (air conditioner), 14 first heat exchanger, 15a second heat exchanger, 15b parallel second heat exchanger, 16 compressor, 17a first expansion valve, 17b second expansion valve, 18 First refrigerant path, 22 First parallel refrigerant path, 24 First branch point, 25 Second refrigerant path, 26 Third refrigerant path, 27 Second branch point, 31 Second parallel refrigerant path, 35 Third parallel refrigerant path, 38,39 First open valve as flow path switching means, 41,42 Second open valve as flow path switching means, 45 Fourth refrigerant path, 60 Refrigerant reservoir, 74 Bypass path, 81 Control circuit.

Claims (5)

A first refrigerant path having a first heat exchanger between the compressor and the first expansion valve, and supplying and blocking high-temperature and high-pressure refrigerant to the first heat exchanger by a flow path switching unit;
When the high-temperature and high-pressure refrigerant is shut off to the first refrigerant path by the flow path switching means, the compression is branched from the first refrigerant path between the compressor and the first heat exchanger. A second refrigerant path for supplying high-temperature and high-pressure refrigerant to the second heat exchanger between the compressor and the first expansion valve;
The refrigerant branches from the second refrigerant path at the second branch point between the compressor and the second heat exchanger, and when the refrigerant is supplied from the first refrigerant path to the first heat exchanger, A third refrigerant path for guiding the refrigerant flowing out of the second heat exchanger to the suction side of the compressor;
The first refrigerant path is branched from the first refrigerant path between the first branch point and the first heat exchanger and connected to the suction side of the compressor. At the time of the interruption by the flow path switching unit of the first refrigerant path Allow the refrigerant to flow from the first refrigerant path, and allow the refrigerant to flow from the first refrigerant path to the third refrigerant path when the refrigerant is supplied from the first refrigerant path to the first heat exchanger. A fourth refrigerant path to be blocked;
A refrigerant reservoir that obtains refrigerant from the first refrigerant path between the first heat exchanger and the first expansion valve and releases the refrigerant toward the third refrigerant path;
A refrigeration cycle apparatus comprising: a bypass path that is connected to the second refrigerant path and the refrigerant reservoir and introduces a high-temperature and high-pressure refrigerant from the second refrigerant path to the refrigerant reservoir. The refrigeration cycle apparatus according to claim 1, wherein the flow path switching means is
A first release valve that is incorporated in the second refrigerant path between the bypass path and the second branch point, and switches supply and interruption of the refrigerant in the first refrigerant path;
A refrigeration cycle apparatus comprising: a second release valve that is incorporated in the third refrigerant path between the compressor and the second branch point, and that switches between circulation and blocking of the refrigerant in the third refrigerant path. . The refrigeration cycle apparatus according to claim 1 or 2,
One or more second expansion valves;
A first parallel refrigerant path branched from the first refrigerant path between the first heat exchanger and the first expansion valve and individually connected to each of the second expansion valves;
A second parallel refrigerant path that branches from the second refrigerant path between the first branch point and the second branch point and is individually connected to each of the second expansion valves;
A parallel second heat exchanger individually incorporated in each of the second parallel refrigerant paths;
A refrigeration cycle apparatus further comprising: a third parallel refrigerant path branched from the second parallel refrigerant path between the bypass path and the parallel second heat exchanger and connected to the third refrigerant path. . The refrigeration cycle apparatus according to claim 3,
When at least one of the second heat exchanger and the parallel second heat exchanger functions as an evaporator, if the degree of superheat of the evaporator is greater than or equal to a predetermined value, the third refrigerant from the refrigerant reservoir A refrigeration cycle apparatus, further comprising: a control circuit that generates a control signal for discharging the refrigerant toward the path. The refrigeration cycle apparatus according to claim 3 or 4,
When all the second heat exchangers and the parallel second heat exchanger function as condensers, if the degree of superheat of the first heat exchanger is equal to or greater than a predetermined value, the third refrigerant is supplied from the refrigerant reservoir. A refrigeration cycle apparatus, further comprising: a control circuit that generates a control signal for discharging the refrigerant toward the path.

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