Heat source unit and refrigerating device

Abstract

The present invention is provided with a controller (130) that controls the supercooling-side pressure reducing valve (46) in accordance with the degree of supercooling of the refrigerant flowing out from the first flow path (28a) of the supercooling heat exchanger (28). The controller (130) determines that the refrigerant is insufficient in the refrigerant circuit (6) on the condition that the degree of opening of the supercooling-side pressure reducing valve (46) is equal to or greater than a predetermined degree of opening.

Description

Technical Field

[0001] The present invention relates to a heat source unit and a refrigeration device. Background Art

[0002] The refrigeration device described in Patent Document 1 includes a heat source unit, which includes a compression unit, a heat source side heat exchanger, and a subcooling heat exchanger. After the refrigerant compressed by the compression unit releases heat in the heat source side heat exchanger, it flows in the first flow path of the subcooling heat exchanger. In the subcooling heat exchanger, the refrigerant flowing in the first flow path exchanges heat with the refrigerant flowing in the second flow path after being reduced in pressure by the subcooling side pressure reducing valve. As a result, the refrigerant flowing in the first flow path is cooled, and the degree of subcooling of the refrigerant increases.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 2019-184231 Summary of the invention

[0006] -Technical problem to be solved by the invention-

[0007] When the refrigeration device described in Patent Document 1 is shipped, the amount of refrigerant filled in the refrigeration device may be insufficient. In addition, the refrigerant may leak from the refrigerant circuit. As a result, the refrigerant in the refrigerant circuit is insufficient, and the refrigeration capacity is reduced.

[0008] The present disclosure aims to provide a heat source unit and a refrigeration device capable of determining that the refrigerant in the refrigerant circuit is insufficient.

[0009] -Technical solutions to solve technical problems-

[0010] The heat source unit of the first aspect includes a refrigerant circuit 6 and a controller 130. The refrigerant circuit 6 includes a compression unit 20, a heat source side heat exchanger 24, a subcooling side pressure reducing valve 46, and a subcooling heat exchanger 28. The subcooling heat exchanger 28 has a first flow path 28a and a second flow path 28b. The first flow path 28a is for the refrigerant that has released heat in the heat source side heat exchanger 24 to flow, and the second flow path 28b is for the refrigerant that has passed through the first flow path 28a and has been decompressed by the subcooling side pressure reducing valve 46 to flow. The controller 130 controls the subcooling side pressure reducing valve 46 according to the degree of subcooling of the refrigerant flowing out of the first flow path 28a of the subcooling heat exchanger 28. The controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient based on the fact that the opening degree of the subcooling side pressure reducing valve 46 becomes larger.

[0011] According to a second aspect, in addition to the first aspect, the controller ( 130 ) determines that the refrigerant in the refrigerant circuit ( 6 ) is insufficient, on the condition that the opening degree of the subcooling-side pressure reducing valve ( 46 ) is equal to or greater than a predetermined opening degree.

[0012] In the second aspect, the controller 130 controls the opening of the subcooling side pressure reducing valve 46 based on the degree of subcooling of the refrigerant flowing out of the first flow path 28a of the subcooling heat exchanger 28. In other words, the opening of the subcooling side pressure reducing valve 46 is adjusted by the so-called subcooling control. Here, when the refrigerant in the refrigerant circuit 6 is insufficient, sufficient liquid refrigerant cannot be sent to the first flow path 28a of the subcooling heat exchanger 28. Therefore, since the degree of subcooling of the refrigerant flowing out of the first flow path 28a becomes smaller or zero, the opening of the subcooling side pressure reducing valve 46 becomes larger. The controller 130 of the present disclosure uses this point to judge whether the refrigerant in the refrigerant circuit 6 is insufficient. Specifically, the controller 130 judges whether the refrigerant in the refrigerant circuit 6 is insufficient on the condition that the opening of the subcooling side pressure reducing valve 46 is above the specified opening.

[0013] Here, assuming that the controller 130 uses the degree of subcooling of the refrigerant flowing out of the first flow path 28a to judge whether the refrigerant in the refrigerant circuit 6 is insufficient, it is possible to erroneously judge that the refrigerant is insufficient when the degree of subcooling temporarily changes for some reason. In contrast, the opening degree of the subcooling side pressure reducing valve 46 has a characteristic of changing more slowly than the degree of subcooling itself. Therefore, it is possible to prevent erroneously judge that the refrigerant in the refrigerant circuit 6 is insufficient when the degree of subcooling temporarily changes.

[0014] A third aspect is based on the second aspect, wherein the controller 130 determines that the refrigerant is insufficient on the condition that the opening degree of the subcooling side pressure reducing valve 46 is greater than or equal to the predetermined opening degree and continues for more than a predetermined time.

[0015] In the third aspect, it is possible to further prevent an erroneous determination that the refrigerant in the refrigerant circuit 6 is insufficient when the degree of subcooling of the refrigerant flowing out of the first flow path 28a temporarily changes for some reason.

[0016] In the fourth aspect, based on the third aspect, the controller 130 determines the refrigerant shortage under the condition that the opening of the subcooling side pressure reducing valve 46 is above the first opening and lasts for more than the first time, or the opening of the subcooling side pressure reducing valve 46 is above the second opening and lasts for more than the second time, the second time is longer than the first time, and the second opening is smaller than the first opening.

[0017] In the fourth aspect, when the opening of the subcooling side pressure reducing valve 46 is at or above a larger first opening for a shorter first time or longer, the controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient. Alternatively, when the opening of the subcooling side pressure reducing valve 46 is at or above a smaller second opening for a longer second time or longer, the controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient.

[0018] According to a fifth aspect, in addition to any one of the first to third aspects, the controller (130) determines that the refrigerant in the refrigerant circuit (6) is insufficient on the condition that the opening of the subcooling-side pressure-reducing valve (46) is fully opened.

[0019] When the refrigerant in the refrigerant circuit 6 is insufficient, so that the degree of subcooling of the refrigerant flowing out of the first flow path 28a becomes small or zero, the opening of the subcooling side pressure reducing valve 46 eventually reaches full opening. The controller 130 of the fourth aspect determines whether the refrigerant in the refrigerant circuit 6 is insufficient on the condition that the opening of the subcooling side pressure reducing valve 46 is in a fully open state, so that the determination of the insufficient refrigerant in the refrigerant circuit 6 can be made with high accuracy.

[0020] According to a sixth aspect, in any one of the first to fifth aspects, the refrigerant circuit (6) is configured to be able to perform a refrigeration cycle in which the high pressure reaches a critical pressure or more.

[0021] In the sixth aspect, a refrigeration cycle in which the high pressure reaches a critical pressure or more is performed in the refrigerant circuit 6. In this refrigeration cycle, the degree of subcooling of the refrigerant flowing out of the first flow path 28a tends to become unstable. However, since the controller 130 uses the opening of the subcooling side pressure reducing valve 46, which changes more slowly than the degree of subcooling, to judge whether the refrigerant is insufficient, it is possible to prevent erroneous judgment of insufficient refrigerant.

[0022] According to a seventh aspect, in addition to any one of the first to sixth aspects, a gas-liquid separator ( 25 ) is provided between the heat source side heat exchanger ( 24 ) and the first flow path ( 28 a ) of the subcooling heat exchanger ( 28 ) in the refrigerant circuit ( 6 ).

[0023] In the seventh aspect, the refrigerant after releasing heat in the heat source side heat exchanger 24 is sent to the gas-liquid separator 25. In the gas-liquid separator 25, the refrigerant is separated into gaseous refrigerant and liquid refrigerant. The liquid refrigerant separated in the gas-liquid separator 25 flows in the first flow path 28a of the subcooling heat exchanger 28. In the subcooling heat exchanger 28, the liquid refrigerant in the first flow path 28a is cooled by the refrigerant in the second flow path 28b, and the degree of subcooling of the liquid refrigerant in the first flow path 28a increases.

[0024] In the structure where the gas-liquid separator 25 is provided in the refrigerant circuit 6 as described above, the gaseous refrigerant separated in the gas-liquid separator 25 sometimes flows temporarily in the first flow path 28a. When the gaseous refrigerant temporarily flows into the first flow path 28a, the degree of supercooling decreases rapidly, and it may be erroneously judged that the refrigerant is insufficient. However, the controller 130 uses the opening of the subcooling side pressure reducing valve 46, which changes slowly compared to the degree of supercooling, to judge whether the refrigerant in the refrigerant circuit 6 is insufficient. Therefore, it is possible to prevent the occurrence of a situation where the gaseous refrigerant separated in the gas-liquid separator 25 temporarily flows in the first flow path 28a, which causes an erroneous judgment that the refrigerant is insufficient.

[0025] An eighth aspect relates to a refrigeration device, comprising the heat source unit (10) as described in any one of the first to seventh aspects, and utilization units (60, 70). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a piping system diagram of a refrigeration device according to an embodiment;

[0027] Figure 2 It is a block diagram showing the connection relationship between the controller and its peripheral devices;

[0028] Figure 3 is a structural diagram of the flow path switching mechanism;

[0029] Figure 4 It is a piping system diagram of a refrigeration unit, which shows the flow of refrigerant when the cooling equipment is in operation;

[0030] Figure 5 It is a piping system diagram of a refrigeration device, which shows the flow of refrigerant in refrigeration operation (defrost operation);

[0031] Figure 6 It is a piping system diagram of a refrigeration device, which shows the flow of refrigerant under the operation of the refrigeration / cooling equipment (defrost operation);

[0032] Figure 7 It is a piping system diagram of a refrigeration unit, which shows the flow of refrigerant in heating operation;

[0033] Figure 8 is a piping system diagram of a refrigeration device, which shows the flow of refrigerant under the operation of a first heating / cooling device;

[0034] Fig. 9 is a piping diagram of a refrigeration unit showing the flow of refrigerant with the second heating / cooling device in operation;

[0035] Fig.10is a piping diagram of a refrigeration unit showing the flow of refrigerant with the third heating / cooling device in operation;

[0036] Fig.11 is a flow chart related to the subcooling control of the injection valve;

[0037] Fig.12 This is a flowchart related to control for determining if refrigerant is insufficient. DETAILED DESCRIPTION

[0038] The following is a detailed description of the embodiments of the present disclosure with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the embodiments shown below, and various changes can be made without departing from the technical concept of the present disclosure. The drawings are used to briefly illustrate the present disclosure, so in order to facilitate understanding, the size, ratio or quantity may be exaggerated or simplified as needed.

[0039] Implementation Method

[0040] The refrigeration device 1 according to the embodiment cools the cooling object and performs indoor air conditioning at the same time. The cooling object mentioned here includes the air in equipment such as refrigerators, freezers, and showcases. Hereinafter, the above equipment is referred to as cooling equipment.

[0041] (1) Overall structure

[0042] like Figure 1 As shown, the refrigeration device 1 includes a heat source unit 10 arranged outdoors, an air conditioning unit 60 for indoor air conditioning, and a cooling device unit 70 for cooling the air in the storage. Figure 1 In FIG. 1 , one air conditioning unit 60 is shown. The refrigeration device 1 may also have more than two air conditioning units 60 connected in parallel. Figure 1 In the figure, one cooling device unit 70 is shown. The refrigeration device 1 may also have more than two cooling device units 70 connected in parallel.

[0043] The refrigeration device 1 includes four connecting pipes 2, 3, 4, and 5 that connect the heat source unit 10, the air conditioning unit 60, and the cooling device unit 70. In the refrigeration device 1, the heat source unit 10, the air conditioning unit 60, and the cooling device unit 70 are connected by these connecting pipes 2, 3, 4, and 5, thereby forming a refrigerant circuit 6.

[0044] The refrigerant circuit 6 contains a filled refrigerant. The refrigerant circulates in the refrigerant circuit 6 to perform a refrigeration cycle. The refrigerant in this embodiment is carbon dioxide. The refrigerant circuit 6 performs a refrigeration cycle in which the refrigerant reaches a critical pressure or higher. The refrigerant may be a natural refrigerant other than carbon dioxide.

[0045] (1-1) Connecting pipes

[0046] The four connecting pipes 2, 3, 4, 5 are composed of a first liquid connecting pipe 2, a first gas connecting pipe 3, a second liquid connecting pipe 4, and a second gas connecting pipe 5. The first liquid connecting pipe 2 and the first gas connecting pipe 3 correspond to the air conditioning unit 60. The second liquid connecting pipe 4 and the second gas connecting pipe 5 correspond to the cooling equipment unit 70.

[0047] (2) Heat source unit

[0048] The heat source unit 10 has a heat source circuit 11 and an outdoor fan 12. The heat source circuit 11 has a compressor 20, an outdoor heat exchanger 24, and a gas-liquid separator 25. The heat source circuit 11 has a first outdoor expansion valve 26 and a second outdoor expansion valve 27. The heat source circuit 11 also has a subcooling heat exchanger 28 and an intercooler 29.

[0049] The heat source circuit 11 has four normally closed valves 13, 14, 15, 16. The four normally closed valves are composed of a first gas side normally closed valve 13, a first liquid side normally closed valve 14, a second gas side normally closed valve 15, and a second liquid side normally closed valve 16.

[0050] The first gas-side normally closed valve 13 is connected to the first gas connecting pipeline 3. The first liquid-side normally closed valve 14 is connected to the first liquid connecting pipeline 2. The second gas-side normally closed valve 15 is connected to the second gas connecting pipeline 5. The second liquid-side normally closed valve 16 is connected to the second liquid connecting pipeline 4.

[0051] The heat source unit 10 has a flow path switching mechanism 30. Figure 1 In the piping system diagram of the refrigerant circuit 6, etc., detailed illustration of the flow switching mechanism 30 is omitted. The flow switching mechanism 30 switches the flow path of the refrigerant in the refrigerant circuit 6. The details of the flow switching mechanism 30 will be described later.

[0052] (2-1) Compression section

[0053] The compression unit 20 compresses the refrigerant. The compression unit 20 includes a first compressor 21, a second compressor 22, and a third compressor 23. The compression unit 20 performs an operation of compressing the refrigerant in a single-stage compression method and an operation of compressing the refrigerant in a two-stage compression method.

[0054] The first compressor 21 is a cooling device compressor corresponding to the cooling device unit 70. The first compressor 21 is an example of a first compression element. The second compressor 22 is an air conditioning compressor corresponding to the air conditioning unit 60. The second compressor 22 is an example of a second compression element. The first compressor 21 and the second compressor 22 are low-stage compressors. The first compressor 21 and the second compressor 22 are connected in parallel.

[0055] The third compressor 23 is a high-pressure side compressor. The third compressor 23 is connected in series with the first compressor 21. The third compressor 23 is connected in series with the second compressor 22.

[0056] The first compressor 21, the second compressor 22, and the third compressor 23 are rotary compressors whose compression mechanisms are driven by electric motors. The first compressor 21, the second compressor 22, and the third compressor 23 are variable capacity compressors. The rotation speeds of the electric motors of the first compressor 21, the second compressor 22, and the third compressor 23 are adjusted by a frequency converter. In other words, the first compressor 21, the second compressor 22, and the third compressor 23 are configured so that their operating capacities can be adjusted.

[0057] A first suction pipe 21a and a first discharge pipe 21b are connected to the first compressor 21. A second suction pipe 22a and a second discharge pipe 22b are connected to the second compressor 22. A third suction pipe 23a and a third discharge pipe 23b are connected to the third compressor 23.

[0058] (2-2) Intermediate flow path

[0059] The heat source circuit 11 includes an intermediate flow path 18. The intermediate flow path 18 connects the discharge parts of the first compressor 21 and the second compressor 22 with the suction part of the third compressor 23. The intermediate flow path 18 includes a first discharge pipe 21b, a second discharge pipe 22b, and a third suction pipe 23a.

[0060] (2-3) Outdoor heat exchanger and outdoor fan

[0061] The outdoor heat exchanger 24 is an example of a heat source side heat exchanger. The outdoor heat exchanger 24 is a fin-tube air heat exchanger. The outdoor fan 12 is arranged near the outdoor heat exchanger 24. The outdoor fan 12 delivers outdoor air. The outdoor heat exchanger exchanges heat between the refrigerant flowing therein and the outdoor air delivered by the outdoor fan 12.

[0062] (2-4) Liquid side flow path

[0063] The heat source circuit 11 includes a liquid flow path 40. The liquid flow path 40 is provided between the liquid end of the outdoor heat exchanger 24 and the two liquid normally closed valves 14 and 16. The liquid flow path 40 includes a first tube 40a, a second tube 40b, a third tube 40c, a fourth tube 40d, and a fifth tube 40e.

[0064] One end of the first tube 40a is connected to the liquid side end of the outdoor heat exchanger 24. The other end of the first tube 40a is connected to the top of the gas-liquid separator 25. One end of the second tube 40b is connected to the bottom of the gas-liquid separator 25. The other end of the second tube 40b is connected to the second liquid side normally closed valve 16. One end of the third tube 40c is connected to the middle of the second tube 40b. The other end of the third tube 40c is connected to the first liquid side normally closed valve 14. One end of the fourth tube 40d is connected to the portion of the first tube 40a located between the first outdoor expansion valve 26 and the gas-liquid separator 25. The other end of the fourth tube 40d is connected to the middle of the third tube 40c. One end of the fifth tube 40e is connected to the portion of the first tube 40a located between the outdoor heat exchanger 24 and the first outdoor expansion valve 26. The other end of the fifth tube 40e is connected to the portion of the second tube 40b located between the connection portion of the second tube 40b and the third tube 40c and the gas-liquid separator 25.

[0065] (2-5) Outdoor expansion valve

[0066] The first outdoor expansion valve 26 is provided on the first pipe 40a. The first outdoor expansion valve 26 is provided on the first pipe 40a between the connection portion of the first pipe 40a and the fourth pipe 40d and the liquid side end of the outdoor heat exchanger 24. The second outdoor expansion valve 27 is provided on the fifth pipe 40e. The first outdoor expansion valve 26 and the second outdoor expansion valve 27 are expansion valves whose openings can be adjusted. The first outdoor expansion valve 26 and the second outdoor expansion valve 27 are electronic expansion valves whose openings are adjusted according to pulse signals.

[0067] (2-6) Gas-liquid separator

[0068] The gas-liquid separator 25 is a sealed container for storing refrigerant. The gas-liquid separator 25 separates the refrigerant into gaseous refrigerant and liquid refrigerant. A gas layer and a liquid layer are formed inside the gas-liquid separator 25. The gas layer is formed on the top side of the gas-liquid separator 25. The liquid layer is formed on the bottom side of the gas-liquid separator 25.

[0069] (2-7) Exhaust pipe

[0070] The heat source circuit 11 has an exhaust pipe 41. One end of the exhaust pipe 41 is connected to the top of the gas-liquid separator 25. The other end of the exhaust pipe 41 is connected to the intermediate flow path 18. The exhaust pipe 41 sends the gas refrigerant in the gas-liquid separator 25 to the intermediate flow path 18.

[0071] The exhaust pipe 41 is provided with an exhaust valve 42. The exhaust valve 42 is an expansion valve whose opening degree can be adjusted. The exhaust valve 42 is an electronic expansion valve whose opening degree is adjusted according to a pulse signal.

[0072] (2-8) Subcooling heat exchanger

[0073] The subcooling heat exchanger 28 has a first flow path 28a as a high-pressure side flow path and a second flow path 28b as a low-pressure side flow path. The subcooling heat exchanger 28 performs heat exchange between the refrigerant in the first flow path 28a and the refrigerant in the second flow path 28b. In other words, the subcooling heat exchanger 28 cools the refrigerant flowing in the first flow path 28a using the refrigerant flowing in the second flow path 28b.

[0074] The second flow path 28b constitutes a part of the injection flow path 43. The injection flow path 43 includes an upstream flow path 44 and a downstream flow path 45.

[0075] One end of the upstream flow path 44 is connected to the third pipe 40c at a position upstream of the connection portion connected to the fourth pipe 40d. The other end of the upstream flow path 44 is connected to the inflow end of the second flow path 28b. An injection valve 46 as a subcooling side pressure reducing valve is provided on the upstream flow path 44. The injection valve 46 is an expansion valve whose opening can be adjusted. The injection valve 46 is an electronic expansion valve whose opening is adjusted according to a pulse signal.

[0076] One end of the downstream flow path 45 is connected to the outflow end of the second flow path 28 b , and the other end of the downstream flow path 45 is connected to the intermediate flow path 18 .

[0077] (2-9) Intercooler

[0078] The intercooler 29 is provided in the intermediate flow path 18. The intercooler 29 is a fin-tube air heat exchanger. A cooling fan 29a is arranged near the intercooler 29. The intercooler 29 exchanges heat between the refrigerant flowing therein and the outdoor air sent by the cooling fan 29a.

[0079] (2-10) Oil separation circuit

[0080] The heat source circuit 11 includes an oil separation circuit. The oil separation circuit includes an oil separator 50 , a first oil return pipe 51 , and a second oil return pipe 52 .

[0081] The oil separator 50 is connected to the third discharge pipe 23b. The oil separator 50 separates oil from the refrigerant discharged from the compression unit 20. The inflow ends of the first oil return pipe 51 and the second oil return pipe 52 are connected to the oil separator 50. The outflow end of the first oil return pipe 51 is connected to the intermediate flow path 18. The first oil return pipe 51 is provided with a first oil amount regulating valve 53.

[0082] The outflow side of the second oil return pipe 52 is separated into a first branch pipe 52a and a second branch pipe 52b. The first branch pipe 52a is connected to the oil storage part of the first compressor 21. The second branch pipe 52b is connected to the oil storage part of the second compressor 22. A second oil quantity regulating valve 54 is provided on the first branch pipe 52a. A third oil quantity regulating valve 55 is provided on the second branch pipe 52b.

[0083] (2-11) Bypass pipe

[0084] The heat source circuit 11 includes a first bypass pipe 56, a second bypass pipe 57, and a third bypass pipe 58. The first bypass pipe 56 corresponds to the first compressor 21. The second bypass pipe 57 corresponds to the second compressor 22. The third bypass pipe 58 corresponds to the third compressor 23.

[0085] Specifically, the first bypass pipe 56 directly connects the first suction pipe 21a and the first discharge pipe 21b. The second bypass pipe 57 directly connects the second suction pipe 22a and the second discharge pipe 22b. The third bypass pipe 58 directly connects the third suction pipe 23a and the third discharge pipe 23b.

[0086] (2-12) Check valve

[0087] The heat source circuit 11 has a plurality of check valves. The plurality of check valves include a first check valve CV1 to a twelfth check valve CV12. These check valves CV1 to CV12 allow the refrigerant to flow toward Figure 1 The refrigerant is allowed to flow in the direction of the arrow, and is prohibited from flowing in the direction opposite to the direction of the arrow.

[0088] The first check valve CV1 and the second check valve CV2 are provided in the flow path switching mechanism 30 , and the details of the flow path switching mechanism 30 will be described later.

[0089] The third check valve CV3 is provided on the third discharge pipe 23b. The fourth check valve CV4 is provided on the first pipe 40a. The fifth check valve CV5 is provided on the third pipe 40c. The sixth check valve CV6 is provided on the fourth pipe 40d. The seventh check valve CV7 is provided on the fifth pipe 40e. The eighth check valve CV8 is provided on the first bypass pipe 56. The ninth check valve CV9 is provided on the second bypass pipe 57. The tenth check valve CV10 is provided on the third bypass pipe 58. The eleventh check valve CV11 is provided on the first discharge pipe 21b. The twelfth check valve CV12 is provided on the second discharge pipe 22b.

[0090] (3) Air conditioning unit

[0091] The air conditioning unit 60 is a first utilization unit installed indoors. The air conditioning unit 60 includes an indoor circuit 61 and an indoor fan 62. A first liquid connection pipe 2 is connected to the liquid side end of the indoor circuit 61. A first gas connection pipe 3 is connected to the gas side end of the indoor circuit 61.

[0092] The indoor circuit 61 includes an indoor expansion valve 63 and an indoor heat exchanger 64 in order from the liquid side end to the gas side end. The indoor expansion valve 63 is an expansion valve whose opening degree can be adjusted. The indoor expansion valve 63 is an electronic expansion valve whose opening degree is adjusted according to a pulse signal.

[0093] The indoor heat exchanger 64 is a fin-tube air heat exchanger. The indoor heat exchanger 64 is an example of a first utilization side heat exchanger. The indoor fan 62 is arranged near the indoor heat exchanger 64. The indoor fan 62 delivers indoor air. The indoor heat exchanger 64 exchanges heat between the refrigerant flowing therein and the indoor air delivered by the indoor fan 62.

[0094] (4) Cooling equipment unit

[0095] The cooling device unit 70 is a second utilization unit for cooling the interior of the storage. The cooling device unit 70 includes a cooling device circuit 71 and a cooling device fan 72. A second liquid connection pipe 4 is connected to the liquid side end of the cooling device circuit 71. A second gas connection pipe 5 is connected to the gas side end of the cooling device circuit 71.

[0096] The cooling device circuit 71 includes a cooling device expansion valve 73 and a cooling device heat exchanger 74 in order from the liquid side end to the gas side end. The cooling device expansion valve 73 is an expansion valve whose opening can be adjusted. The cooling device expansion valve 73 is an electronic expansion valve whose opening is adjusted according to a pulse signal.

[0097] The cooling device heat exchanger 74 is a fin-tube air heat exchanger. The cooling device heat exchanger 74 is an example of the second utilization side heat exchanger. The cooling device fan 72 is arranged near the cooling device heat exchanger 74. The cooling device fan 72 conveys the air in the storage. The cooling device heat exchanger 74 exchanges heat between the refrigerant flowing therein and the air in the storage conveyed by the cooling device fan 72.

[0098] The evaporation temperature of the cooling device heat exchanger 74 is lower than the evaporation temperature of the indoor heat exchanger 64 .

[0099] (5) Flow path switching mechanism

[0100] The flow path switching mechanism 30 is provided in the heat source circuit 11. Figure 1 and Figure 3 As shown, the flow path switching mechanism 30 has a first valve port P1, a second valve port P2, a third valve port P3, a fourth valve port P4, a switching first flow path 31, a switching second flow path 32, a switching third flow path 33, and a switching fourth flow path 34. A first switch mechanism 81 is provided in switching the first flow path 31, a second switch mechanism 82 is provided in switching the second flow path 32, a third switch mechanism 83 is provided in switching the third flow path 33, and a fourth switch mechanism 84 is provided in switching the fourth flow path 34.

[0101] (5-1) Valve port

[0102] The first valve port P1 is connected to the discharge portion of the first compressor 21 and the discharge portion of the second compressor 22. The discharge portion of the first compressor 21 is connected to the first valve port P1 via the first discharge line L1. The first discharge line L1 is a flow path connected to the discharge portion of the first compressor 21 at one end and connected to the first valve port P1 at the other end. In other words, the first discharge line L1 is a flow path extending from the discharge portion of the first compressor 21 to the first valve port P1.

[0103] The discharge portion of the second compressor 22 is connected to the first valve port P1 via the second discharge line L2. The second discharge line L2 is a flow path connected to the discharge portion of the second compressor 22 at one end and connected to the first valve port P1 at the other end. In other words, the second discharge line L2 is a flow path extending from the discharge portion of the second compressor 22 to the first valve port P1.

[0104] The second valve port P2 is connected to the suction part of the second compressor 22. The second valve port P2 is not connected to the suction part of the first compressor 21. The second valve port P2 is connected to the suction part of the second compressor 22 via the suction line L3. The suction line L3 is a flow path connected to the suction part of the second compressor 22 at one end and connected to the second valve port P2 at the other end. In other words, the suction line L3 is a flow path extending from the suction part of the second compressor 22 to the second valve port P2.

[0105] The third valve port P3 is connected to the gas side end of the indoor heat exchanger 64. The third valve port P3 is connected to the gas side end of the indoor heat exchanger 64 via the first gas pipeline L4. The first gas pipeline L4 is a flow path connected to the indoor heat exchanger 64 at one end and connected to the third valve port P3 at the other end. In other words, the first gas pipeline L4 is a flow path extending from the gas side end of the indoor heat exchanger 64 to the third valve port P3.

[0106] The fourth valve port P4 is connected to the gas side end of the outdoor heat exchanger 24. The fourth valve port P4 is connected to the gas side end of the outdoor heat exchanger 24 via the second gas pipeline L5. One end of the second gas pipeline L5 is connected to the gas side end of the outdoor heat exchanger 24, and the other end is connected to the fourth valve port P4. The second gas pipeline L5 is a flow path extending from the gas side end of the outdoor heat exchanger 24 to the fourth valve port P4.

[0107] The first discharge line L1 , the second discharge line L2 , the suction line L3 , the first gas line L4 , and the second gas line L5 are flow paths including pipes and element equipment connected to the pipes.

[0108] (5-2)Flow path

[0109] like Figure 1 As schematically shown in FIG. 1 , switching the first flow path 31, switching the second flow path 32, switching the third flow path 33, and switching the fourth flow path 34 are connected in a bridge shape. Switching the first flow path 31 connects the first valve port P1 with the third valve port P3. Switching the second flow path 32 connects the first valve port P1 with the fourth valve port P4. Switching the third flow path 33 connects the second valve port P2 with the third valve port P3. Switching the fourth flow path 34 connects the second valve port P2 with the fourth valve port P4. Switching the first flow path 31 and switching the second flow path 32 are high-pressure side flow paths acted upon by high-pressure pressure. In other words, switching the first flow path 31 and switching the second flow path 32 are discharge side flow paths acted upon by the discharge pressure of the compression section 20. Switching the third flow path 33 and switching the fourth flow path 34 are low-pressure side flow paths acted upon by low-pressure pressure. Switching the third flow path 33 and switching the fourth flow path 34 are suction side flow paths acted upon by the suction pressure of the compression section 20.

[0110] like Figure 3 As shown, the switching first flow path 31 has more than two first branch flow paths 31a connected in parallel. The switching first flow path 31 of this example has seven first branch flow paths 31a. The switching second flow path 32 has more than two second branch flow paths 32a connected in parallel. The switching second flow path 32 of this example has seven second branch flow paths 32a. The switching third flow path 33 has third branch flow paths 33a connected in parallel. The switching third flow path 33 of this example has four third branch flow paths 33a. The switching fourth flow path 34 is composed of one flow path.

[0111] (5-3) Switch mechanism

[0112] The first switch mechanism 81 has a plurality of first switch valves V1. More than two first switch valves V1 are arranged in parallel in the switching first flow path 31. In the switching first flow path 31 of this example, seven first switch valves V1 are arranged. A first switch valve V1 is respectively arranged in each first branch flow path 31a. The plurality of first switch valves V1 include a first expansion valve 91 and a first electromagnetic switch valve 92. The number of the first expansion valve 91 is one, and the number of the first electromagnetic switch valves 92 is six. The first expansion valve 91 is an electronic expansion valve with a variable opening.

[0113] The second switch mechanism 82 has a plurality of second switch valves V2. Two or more second switch valves V2 are arranged in parallel in the switching second flow path 32. Seven second switch valves V2 are arranged in the switching second flow path 32 of this example. A second switch valve V2 is respectively arranged in each second branch flow path 32a. The plurality of second switch valves V2 include a second expansion valve 93 and a second electromagnetic switch valve 94. The number of the second expansion valve 93 is one, and the number of the second electromagnetic switch valves 94 is six. The second expansion valve 93 is an electronic expansion valve with a variable opening.

[0114] The third switch mechanism 83 has a plurality of third switch valves V3. Two or more third switch valves V3 are arranged in parallel in the switching second flow path 32. Four third switch valves V3 are arranged in the switching third flow path 33 of this example. One third switch valve V3 is arranged in each third branch flow path 33a. These third switch valves V3 are electromagnetic switch valves.

[0115] The fourth switch mechanism 84 has one fourth switch valve V4. The fourth switch valve V4 is provided in the switching fourth flow path 34. The fourth switch valve V4 is an electromagnetic switch valve.

[0116] Sometimes Figure 2 As shown, the first switching valve V1 , the second switching valve V2 , the third switching valve V3 , and the fourth switching valve V4 are simply referred to as switching valves V.

[0117] (5-5) Check valve

[0118] The flow path switching mechanism 30 includes check valves CV1 and CV2. Specifically, the first check valve CV1 is provided in the switching fourth flow path 34. The second check valve CV2 is provided in the switching first flow path 31.

[0119] The first check valve CV1 restricts the refrigerant from flowing from the second valve port P2 toward the fourth valve port P4 in the switching fourth flow path 34. Strictly speaking, the first check valve CV1 allows the refrigerant to flow from the fourth valve port P4 toward the second valve port P2 in the switching fourth flow path 34, and prohibits the refrigerant from flowing from the second valve port P2 toward the fourth valve port P4 in the switching fourth flow path 34. The first check valve CV1 is disposed at a position closer to the second valve port P2 than the on-off valve V in the switching fourth flow path 34.

[0120] The second check valve CV2 restricts the refrigerant from flowing from the third valve port P3 toward the first valve port P1 in the switching first flow path 31. Strictly speaking, the second check valve CV2 allows the refrigerant to flow from the first valve port P1 toward the third valve port P3 in the switching first flow path 31, and prohibits the refrigerant from flowing from the third valve port P3 toward the first valve port P1 in the switching first flow path 31. The second check valve CV2 is arranged in the main flow path 31b in the switching first flow path 31. The main flow path 31b is a flow path to which the ends of a plurality of first branch flow paths 31a are connected. The second check valve CV2 is arranged in the switching first flow path 31 at a position closer to the third valve port P3 than the switch valve V.

[0121] (6) Sensor

[0122] like Figure 1 As shown, the refrigeration device 1 has a plurality of sensors including a refrigerant pressure sensor for detecting the pressure of the refrigerant, a refrigerant temperature sensor for detecting the temperature of the refrigerant, and an air temperature sensor for detecting the temperature of the air.

[0123] The refrigerant pressure sensor includes a high-pressure pressure sensor 101, an intermediate pressure sensor 102, a first suction pressure sensor 103, a second suction pressure sensor 104, and a liquid side pressure sensor 105. The high-pressure pressure sensor 101 is arranged on the third discharge pipe 23b. The high-pressure pressure sensor 101 detects the pressure of the discharge side refrigerant of the compression unit 20, in other words, detects the high pressure pressure of the refrigerant circuit 6. The intermediate pressure sensor 102 is arranged on the third suction pipe 23a. The intermediate pressure sensor 102 detects the pressure of the refrigerant between the low-stage side compressor and the high-stage side compressor, in other words, detects the intermediate pressure of the refrigerant circuit 6. The first suction pressure sensor 103 is arranged on the first suction pipe 21a. The first suction pressure sensor 103 detects the pressure of the suction side refrigerant of the first compressor 21. The second suction pressure sensor 104 is arranged on the second suction pipe 22a. The second suction pressure sensor 104 detects the pressure of the suction side refrigerant of the second compressor 22.

[0124] The liquid side pressure sensor 105 is provided in the liquid side flow path 40. Specifically, the liquid side pressure sensor 105 is provided in the second tube 40b. The liquid side pressure sensor 105 detects a pressure corresponding to the internal pressure of the gas-liquid separator 25. The liquid side pressure sensor 105 detects a pressure corresponding to the pressure of the refrigerant in the first flow path 28a.

[0125] The refrigerant temperature sensor includes a first discharge temperature sensor 111, a first suction temperature sensor 112, a second discharge temperature sensor 113, a second suction temperature sensor 114, a third discharge temperature sensor 115, a third suction temperature sensor 116, a liquid side temperature sensor 117, an injection side temperature sensor 118, and a heat source side temperature sensor 119. The first discharge temperature sensor 111 is provided on the first discharge pipe 21b, and detects the temperature of the refrigerant discharged from the first compressor 21. The first suction temperature sensor 112 is provided on the first suction pipe 21a, and detects the temperature of the refrigerant sucked into the first compressor 21. The second discharge temperature sensor 113 is provided on the second discharge pipe 22b, and detects the temperature of the refrigerant discharged from the second compressor 22. The second suction temperature sensor 114 is provided on the second suction pipe 22a, and detects the temperature of the refrigerant sucked into the second compressor 22. The third discharge temperature sensor 115 is provided on the third discharge pipe 23b, and detects the temperature of the refrigerant discharged from the third compressor 23. The third suction temperature sensor 116 is provided on the third suction pipe 23 a and detects the temperature of the refrigerant sucked into the third compressor 23 .

[0126] The liquid side temperature sensor 117 is provided on the liquid side flow path 40. Specifically, the liquid side temperature sensor 117 is provided on the outflow side of the first flow path 28a of the subcooling heat exchanger 28 on the liquid side flow path 40. More specifically, the liquid side temperature sensor 117 is provided at a portion of the liquid side flow path 40 between the outflow end of the first flow path 28a and the inflow end of the injection flow path 43. The liquid side temperature sensor 117 detects the temperature of the refrigerant flowing out of the first flow path 28a.

[0127] The injection side temperature sensor 118 is provided on the downstream flow path 45 of the injection flow path 43. In other words, the injection side temperature sensor 118 is provided on the outflow side of the second flow path 28b of the subcooling heat exchanger 28. The injection side temperature sensor 118 detects the temperature of the refrigerant flowing out of the second flow path 28b.

[0128] The heat source side temperature sensor 119 is provided on the heat transfer tube of the outdoor heat exchanger 24. The heat source side temperature sensor 119 is provided at the liquid side end of the outdoor heat exchanger 24. The heat source side temperature sensor 119 detects the temperature of the refrigerant at the liquid side end of the outdoor heat exchanger 24.

[0129] The air temperature sensor includes an outdoor air temperature sensor 121. The outdoor air temperature sensor 121 detects the temperature of outdoor air.

[0130] (7) Controller

[0131] like Figure 2 As shown, the refrigeration device 1 includes a controller 130 for controlling the refrigerant circuit 6. The controller 130 includes a microcomputer mounted on a control substrate and a storage device (specifically, a semiconductor memory) storing software for operating the microcomputer.

[0132] like Figure 2 As shown, the controller 130 includes an outdoor controller 131, an indoor controller 132, and a cooling device controller 133. Figure 1 As shown, the outdoor controller 131 is provided in the heat source unit 10. The indoor controller 132 is provided in the air conditioning unit 60. The cooling device controller 133 is provided in the cooling device unit 70. The outdoor controller 131 can communicate with the indoor controller 132 and the cooling device controller 133.

[0133] The controller 130 receives control instructions and detection signals from various sensors. The controller 130 controls various devices of the refrigeration device 1. Specifically, the controller 130 controls the on / off of the first compressor 21, the second compressor 22, and the third compressor 23. The controller 130 adjusts the capacity (strictly speaking, the speed of the motor) of the first compressor 21, the second compressor 22, and the third compressor 23. The controller 130 controls the on / off of each fan 12, 62, 72. The controller 130 adjusts the opening of each expansion valve 26, 27, 63. The controller 130 switches the on / off state of each valve 42, 43. The controller 130 switches the on / off state of each switch valve V, or adjusts the opening of each switch valve V.

[0134] The controller 130 obtains the degree of subcooling sc of the refrigerant flowing out of the first flow path 28a of the subcooling heat exchanger 28. The controller 130 obtains the degree of subcooling sc based on the detection values ​​of the liquid side pressure sensor 105 and the liquid side temperature sensor 117. Specifically, the controller 130 uses the difference between the saturation temperature corresponding to the detection pressure of the liquid side pressure sensor 105 and the detection temperature of the liquid side temperature sensor 117 as the degree of subcooling sc. The liquid side pressure sensor 105 and the liquid side temperature sensor 117 constitute a degree of subcooling acquisition unit for obtaining the degree of subcooling sc.

[0135] The controller 130 controls the opening of the injection valve 46 according to the subcooling degree sc. The controller 130 controls the opening of the injection valve 46 so that the current subcooling degree sc becomes the target subcooling degree Tsc. The details of the subcooling degree control will be described later.

[0136] When performing supercooling control, the controller 130 determines whether there is insufficient refrigerant in the refrigerant circuit 6. Here, insufficient refrigerant in the refrigerant circuit 6 means that the amount of refrigerant filled in the refrigerant circuit 6 is less than a specified amount. When there is insufficient refrigerant in the refrigerant circuit 6, the desired refrigeration cycle cannot be performed, and the refrigeration capacity of the refrigeration device 1 is reduced.

[0137] The controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient based on the opening of the injection valve 46. The controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient when the opening of the injection valve 46 is greater than a predetermined value. The details of this determination will be described later.

[0138] The controller 130 includes a notification unit 134 for notifying the controller 130 that the refrigerant in the refrigerant circuit 6 is insufficient. Figure 2As shown, the notification unit 134 is provided in the outdoor controller 130, for example. When the controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient, the notification unit 134 notifies the subject person of the insufficient refrigerant in the refrigerant circuit 6. The subject person includes a user, a service provider, a maintenance service provider, a manufacturer, etc. The notification unit 134 may also be a display unit that notifies the insufficient refrigerant using text, symbols, icons, etc. like a monitor. The notification unit 134 may also be a light-emitting unit such as an LED that notifies the insufficient refrigerant using light, etc. The notification unit 134 may also be a notification unit that notifies the insufficient refrigerant to the subject person using an email, etc.

[0139] (8) Operation

[0140] The operation of the refrigeration device 1 is described. The operation of the refrigeration device 1 includes cooling device operation, cooling operation, cooling / cooling device operation, heating operation, heating / cooling device operation, and defrosting operation. The heating / cooling device operation includes a first heating / cooling device operation, a second heating / cooling device operation, and a third heating / cooling device operation.

[0141] In the cooling device operation, the cooling device unit 70 cools the air in the warehouse, and the air conditioning unit 60 stops. In the cooling operation, the cooling device unit 70 stops, and the air conditioning unit 60 cools the room. In the cooling / cooling device operation, the cooling device unit 70 cools the air in the warehouse, and the air conditioning unit 60 cools the room. In the heating operation, the cooling device unit 70 stops, and the air conditioning unit 60 heats the room. In the heating / cooling device operation, the cooling device unit 70 cools the air in the warehouse, and the air conditioning unit 60 heats the room. In the defrosting operation, the frost attached to the outdoor heat exchanger 24 melts.

[0142] The first heating / cooling device operation is an operation in which the heat taken away by the refrigerant in the outdoor heat exchanger 24 and the cooling device heat exchanger 74 is used for heating. The second heating / cooling device operation is an operation in which the outdoor heat exchanger 24 is not functioned and the heat taken away by the refrigerant in the cooling device heat exchanger 74 is used for heating. The third heating / cooling device operation is an operation in which the heat of the refrigerant is released from the outdoor heat exchanger 24.

[0143] Reference Figures 4 to 10 The following briefly describes each operation. It should be noted that in the figure, the flow of the refrigerant is indicated by a dotted arrow, and the flow path of the refrigerant is indicated by a bold line. In the figure, a heat exchanger that functions as a radiator is drawn with a slash, and a heat exchanger that functions as an evaporator is drawn with a black dot.

[0144] (8-1) Cooling equipment operation

[0145] exist Figure 4 In the operation of the cooling device shown, the controller 130 closes the first switch valve V1, the third switch valve V3, and the fourth switch valve V4, and opens the second switch valve V2. The controller 130 stops the second compressor 22 and operates the first compressor 21 and the third compressor 23. The controller 130 opens the first outdoor expansion valve 26 and the injection valve 46 at a specified opening, and closes the second outdoor expansion valve 27. The controller 130 closes the indoor expansion valve 63 and adjusts the opening of the cooling device expansion valve 73. The controller 130 operates the outdoor fan 12 and the cooling device fan 72, and stops the indoor fan 62.

[0146] In the cooling device operation, a refrigeration cycle is performed in which the outdoor heat exchanger 24 functions as a radiator, the function of the indoor heat exchanger 64 is substantially stopped, and the cooling device heat exchanger 74 functions as an evaporator.

[0147] Specifically, the refrigerant compressed by the first compressor 21 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed to a pressure above the critical pressure by the third compressor 23 releases heat in the outdoor heat exchanger 24 and then passes through the first outdoor expansion valve 26. The first outdoor expansion valve 26 decompresses the refrigerant to a pressure lower than the critical pressure.

[0148] The refrigerant that has reached a subcritical state flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into a gaseous refrigerant and a liquid refrigerant.

[0149] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0150] The refrigerant cooled by the subcooling heat exchanger 28 is sent to the cooling device unit 70. The refrigerant sent to the cooling device unit 70 is decompressed by the cooling device expansion valve 73 and evaporated in the cooling device heat exchanger 74. As a result, the air in the storage is cooled. The refrigerant evaporated in the cooling device heat exchanger 74 is sucked into the first compressor 21 and compressed again.

[0151] (8-2) Refrigeration Operation

[0152] exist Figure 5In the cooling operation shown, the controller 130 closes the first on-off valve V1 and the fourth on-off valve V4, and opens the second on-off valve V2 and the third on-off valve V3. The controller 130 stops the first compressor 21, and operates the second compressor 22 and the third compressor 23. The controller 130 opens the first outdoor expansion valve 26 and the injection valve 46 at a specified opening, and closes the second outdoor expansion valve 27. The controller 130 closes the cooling device expansion valve 73, and adjusts the opening of the indoor expansion valve 63. The controller 130 operates the outdoor fan 12 and the indoor fan 62, and stops the cooling device fan 72.

[0153] In the cooling operation, a refrigeration cycle is performed in which the outdoor heat exchanger 24 functions as a radiator, the indoor heat exchanger 64 functions as an evaporator, and the function of the cooling device heat exchanger 74 is substantially stopped.

[0154] Specifically, the refrigerant compressed by the second compressor 22 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed to a pressure above the critical pressure by the third compressor 23 releases heat in the outdoor heat exchanger 24 and then passes through the first outdoor expansion valve 26. The first outdoor expansion valve 26 decompresses the refrigerant to a pressure lower than the critical pressure.

[0155] The refrigerant that has reached a subcritical state flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into a gaseous refrigerant and a liquid refrigerant.

[0156] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0157] The refrigerant cooled by the subcooling heat exchanger 28 is sent to the air conditioning unit 60. The refrigerant sent to the air conditioning unit 60 is decompressed by the indoor expansion valve 63 and evaporated in the indoor heat exchanger 64. As a result, the indoor air is cooled. The refrigerant evaporated in the indoor heat exchanger 64 is sucked into the second compressor 22 and compressed again.

[0158] (8-3) Refrigeration / Cooling Equipment Operation

[0159] exist Figure 6In the operation of the refrigeration / cooling device shown, the controller 130 closes the first on / off valve V1 and the fourth on / off valve V4, and opens the second on / off valve V2 and the third on / off valve V3. The controller 130 operates the first compressor 21, the second compressor 22, and the third compressor 23. The controller 130 opens the first outdoor expansion valve 26 and the injection valve 46 at a specified opening, and closes the second outdoor expansion valve 27. The controller 130 adjusts the opening of the cooling device expansion valve 73 and the indoor expansion valve 63. The controller 130 operates the outdoor fan 12, the indoor fan 62, and the cooling device fan 72.

[0160] In the refrigeration / cooling device operation, a refrigeration cycle is performed in which the outdoor heat exchanger 24 functions as a radiator and the indoor heat exchanger 64 and the cooling device heat exchanger 74 function as evaporators.

[0161] Specifically, the refrigerant compressed by the first compressor 21 and the second compressor 22 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed to a pressure above the critical pressure by the third compressor 23 releases heat in the outdoor heat exchanger 24 and then passes through the first outdoor expansion valve 26. The first outdoor expansion valve 26 decompresses the refrigerant to a pressure lower than the critical pressure.

[0162] The refrigerant that has reached a subcritical state flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into a gaseous refrigerant and a liquid refrigerant.

[0163] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0164] The refrigerant cooled by the subcooling heat exchanger 28 is sent to the air conditioning unit 60 and the cooling device unit 70. The refrigerant sent to the air conditioning unit 60 is decompressed by the indoor expansion valve 63 and evaporated in the indoor heat exchanger 64. As a result, the indoor air is cooled. The refrigerant evaporated in the indoor heat exchanger 64 is sucked into the first compressor 21 and compressed again.

[0165] The refrigerant sent to the cooling device unit 70 is decompressed by the cooling device expansion valve 73 and evaporates in the cooling device heat exchanger 74. As a result, the air in the storage is cooled. The refrigerant evaporated in the cooling device heat exchanger 74 is sucked into the second compressor 22 and compressed again.

[0166] (8-4) Heating operation

[0167] exist Figure 7In the heating operation shown, the controller 130 closes the second on-off valve V2 and the third on-off valve V3, and opens the first on-off valve V1 and the fourth on-off valve V4. The controller 130 stops the first compressor 21, and operates the second compressor 22 and the third compressor 23. The controller 130 opens the second outdoor expansion valve 27 and the injection valve 46 at a specified opening, and closes the first outdoor expansion valve 26. The controller 130 closes the cooling device expansion valve 73, and adjusts the opening of the indoor expansion valve 63. The controller 130 operates the outdoor fan 12 and the indoor fan 62, and stops the cooling device fan 72.

[0168] In the heating operation, a refrigeration cycle is performed in which the indoor heat exchanger 64 functions as a radiator, the outdoor heat exchanger 24 functions as an evaporator, and the function of the cooling device heat exchanger 74 is substantially stopped.

[0169] Specifically, the refrigerant compressed by the second compressor 22 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed by the third compressor 23 is sent to the air conditioning unit 60.

[0170] The refrigerant sent to the air conditioning unit 60 releases heat in the indoor heat exchanger 64. As a result, the indoor air is heated. The refrigerant after releasing heat in the indoor heat exchanger 64 flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into gaseous refrigerant and liquid refrigerant.

[0171] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0172] The refrigerant cooled in the subcooling heat exchanger 28 is decompressed by the second outdoor expansion valve 27 and evaporates in the outdoor heat exchanger 24. The refrigerant evaporated in the outdoor heat exchanger 24 is sucked into the second compressor 22 and compressed again.

[0173] (8-5) Operation of the first heating / cooling equipment

[0174] Figure 8The first heating / cooling device operation shown is performed when the heating load of the air conditioning unit 60 is high. In the first heating / cooling device operation, the controller 130 closes the second switch valve V2 and the third switch valve V3, and opens the first switch valve V1 and the fourth switch valve V4. The controller 130 operates the first compressor 21, the second compressor 22, and the third compressor 23. The controller 130 opens the second outdoor expansion valve 27 and the injection valve 46 at a prescribed opening, and closes the first outdoor expansion valve 26. The controller 130 adjusts the opening of the indoor expansion valve 63 and the cooling device expansion valve 73. The controller 130 operates the outdoor fan 12, the indoor fan 62, and the cooling device fan 72.

[0175] In the first heating / cooling device operation, a refrigeration cycle is performed in which the indoor heat exchanger 64 functions as a radiator and the outdoor heat exchanger 24 and the cooling device heat exchanger 74 function as evaporators.

[0176] Specifically, the refrigerant compressed by the first compressor 21 and the second compressor 22 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed by the third compressor 23 is sent to the air conditioning unit 60.

[0177] The refrigerant sent to the air conditioning unit 60 releases heat in the indoor heat exchanger 64. As a result, the indoor air is heated. The refrigerant after releasing heat in the indoor heat exchanger 64 flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into gaseous refrigerant and liquid refrigerant.

[0178] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0179] A part of the refrigerant cooled in the subcooling heat exchanger 28 is decompressed by the second outdoor expansion valve 27 and evaporates in the outdoor heat exchanger 24. The refrigerant evaporated in the outdoor heat exchanger 24 is sucked into the first compressor 21 and compressed again.

[0180] The remaining part of the refrigerant cooled by the subcooling heat exchanger 28 is sent to the cooling device unit 70. The refrigerant sent to the cooling device unit 70 is decompressed by the cooling device expansion valve 73 and evaporated in the cooling device heat exchanger 74. As a result, the air in the warehouse is cooled. The refrigerant evaporated in the cooling device heat exchanger 74 is sucked into the second compressor 22 and compressed again.

[0181] (8-6) Second heating / cooling equipment operation

[0182] Fig. 9The second heating / cooling device operation shown is performed when the heating load of the air conditioning unit 60 is neither too high nor too low. In the second heating / cooling device operation, the controller 130 closes the second switch valve V2, the third switch valve V3, and the fourth switch valve V4, and opens the first switch valve V1. The controller 130 operates the first compressor 21 and the third compressor 23, and stops the second compressor 22. The controller 130 opens the injection valve 46 at a specified opening, and closes the first outdoor expansion valve 26 and the second outdoor expansion valve 27. The controller 130 adjusts the opening of the indoor expansion valve 63 and the cooling device expansion valve 73. The controller 130 stops the outdoor fan 12, and operates the indoor fan 62 and the cooling device fan 72.

[0183] In the second heating / cooling device operation, a refrigeration cycle is performed in which the indoor heat exchanger 64 functions as a radiator, the outdoor heat exchanger 24 is substantially stopped, and the cooling device heat exchanger 74 functions as an evaporator.

[0184] Specifically, the refrigerant compressed by the first compressor 21 is cooled in the intercooler 29 and then sucked into the third compressor 23. The refrigerant compressed by the third compressor 23 is sent to the air conditioning unit 60.

[0185] The refrigerant sent to the air conditioning unit 60 releases heat in the indoor heat exchanger 64. As a result, the indoor air is heated. The refrigerant after releasing heat in the indoor heat exchanger 64 flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into gaseous refrigerant and liquid refrigerant.

[0186] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0187] The refrigerant cooled by the subcooling heat exchanger 28 is decompressed by the cooling device expansion valve 73 and evaporates in the cooling device heat exchanger 74. As a result, the air in the storage is cooled. The refrigerant evaporated in the cooling device heat exchanger 74 is sucked into the first compressor 21 and compressed again.

[0188] (8-7) Operation of the third heating / cooling equipment

[0189] Fig.10The third heating / cooling device operation shown is performed when the heating load of the air conditioning unit 60 is low. In the second heating / cooling device operation, the controller 130 closes the third switch valve V3 and the fourth switch valve V4, and opens the first switch valve V1 and the second switch valve V2. The controller 130 operates the first compressor 21 and the third compressor 23, and stops the second compressor 22. The controller 130 opens the injection valve 46 and the first outdoor expansion valve 26 at a prescribed opening, and closes the second outdoor expansion valve 27. The controller 130 adjusts the opening of the indoor expansion valve 63 and the cooling device expansion valve 73. The controller 130 operates the outdoor fan 12, the indoor fan 62, and the cooling device fan 72.

[0190] In the third heating / cooling equipment operation, a refrigeration cycle is performed in which the indoor heat exchanger 64 and the outdoor heat exchanger 24 function as radiators and the cooling equipment heat exchanger 74 functions as an evaporator.

[0191] Specifically, the refrigerant compressed by the first compressor 21 is cooled in the intercooler 29 and then sucked into the third compressor 23. A portion of the refrigerant compressed by the third compressor 23 is sent to the air conditioning unit 60. The refrigerant sent to the air conditioning unit 60 releases heat in the indoor heat exchanger 64. As a result, the indoor air is heated. The refrigerant that releases heat in the indoor heat exchanger 64 flows into the gas-liquid separator 25. The remaining portion of the refrigerant compressed by the third compressor 23 releases heat in the outdoor heat exchanger 24 and then flows into the gas-liquid separator 25. The gas-liquid separator 25 separates the refrigerant into gaseous refrigerant and liquid refrigerant.

[0192] The liquid refrigerant separated in the gas-liquid separator 25 is cooled in the subcooling heat exchanger 28 by the refrigerant flowing through the injection flow path 43. The refrigerant in the injection flow path 43 is sent to the intermediate flow path 18.

[0193] The refrigerant cooled by the subcooling heat exchanger 28 is decompressed by the cooling device expansion valve 73 and evaporates in the cooling device heat exchanger 74. As a result, the air in the storage is cooled. The refrigerant evaporated in the cooling device heat exchanger 74 is sucked into the first compressor 21 and compressed again.

[0194] (8-8) Defrost operation

[0195] The defrosting operation is performed to melt the frost attached to the outdoor heat exchanger 24 in winter. The controller 130 performs the defrosting operation when the condition indicating that the outdoor heat exchanger 24 is frosted is satisfied during the operation of the heating / cooling equipment. Figure 5 The cooling operation shown, Figure 6The refrigeration / cooling devices shown operate in the same manner. In the outdoor heat exchanger 24, the high-pressure refrigerant releases heat to the outside, thereby melting the frost on the surface of the outdoor heat exchanger 24.

[0196] (9) Subcooling control

[0197] The refrigeration device 1 controls the degree of subcooling sc of the refrigerant flowing out of the first flow path 28a of the subcooling heat exchanger 28 in each of the above-mentioned operations. Fig.11 The subcooling degree control will be described.

[0198] In step S11, the controller 130 determines whether the degree of supercooling sc is less than the target degree of supercooling Tsc. Here, the degree of supercooling sc may be the average value of the degree of supercooling at the current moment and one or more degrees of supercooling at a predetermined time before the current moment, etc. In the case where the degree of supercooling sc is less than the target degree of supercooling Tsc, the process transfers to step S13. In step S13, the controller 130 adds a pulse corresponding to the difference (Tsc-sc) between the target degree of supercooling Tsc and the degree of supercooling sc to the current pulse of the injection valve 46. The pulse referred to here refers to the modulation amplitude of the pulse signal (opening instruction) used to control the opening of the injection valve 46. As a result, the opening of the injection valve 46 changes in an increasing manner according to the pulse obtained by the addition. The greater the difference between the target degree of supercooling Tsc and the degree of supercooling sc, the greater the pulse added in step S13. In other words, the greater the difference between the target degree of supercooling Tsc and the degree of supercooling sc, the greater the increase in the opening of the injection valve 46. The smaller the difference is, the smaller the increase in the opening degree of the injection valve 46 is.

[0199] In step S12, the controller 130 determines whether the supercooling degree sc is greater than the target supercooling degree Tsc. When the supercooling degree sc is greater than the target supercooling degree Tsc, the process transfers to step S14. In step S14, the controller 130 subtracts the pulse corresponding to the difference (sc-Tsc) between the supercooling degree sc and the target supercooling degree Tsc from the current pulse of the injection valve 46. As a result, the opening of the injection valve 46 changes in a decreasing manner according to the pulse obtained by subtraction. The greater the difference between the supercooling degree sc and the target supercooling degree Tsc, the greater the pulse subtracted in step S14. In other words, the greater the difference between the supercooling degree sc and the target supercooling degree Tsc, the greater the decrease in the opening of the injection valve 46. The smaller the difference, the smaller the decrease in the opening of the injection valve 46.

[0200] In the subcooling degree control, the control related to steps S11 to S14 is repeatedly performed every predetermined time (for example, 10 seconds). As a result, the subcooling degree sc gradually converges to the target subcooling degree Tsc.

[0201] (10) Regarding insufficient refrigerant

[0202] (10-1) Technical issues

[0203] When the refrigeration device 1 is shipped from the factory or installed, the amount of refrigerant filled in the refrigerant circuit 6 may be less. In particular, in the refrigeration device 1 that uses carbon dioxide to make the high pressure reach above the critical pressure, the amount of refrigerant filled in the refrigerant circuit 6 may be set to be less in consideration of the pressure resistance of the gas-liquid separator 25, etc. In addition, in the refrigeration device 1 after installation, the refrigerant in the refrigerant circuit 6 may leak out. In this way, when the refrigerant in the refrigerant circuit 6 is insufficient, the cooling capacity of the refrigeration device 1 may be reduced.

[0204] (10-2) Judgment Control

[0205] In order to solve the above technical problems, in the present embodiment, the controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient. The controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient during the above-mentioned supercooling degree control. Fig.12 This determination control will be described in detail.

[0206] In step S21, the controller 130 determines whether the opening of the injection valve 46 is greater than the first opening and has continued for a predetermined time (first time) or more. In the present embodiment, the first opening is the fully open opening of the injection valve 46. In other words, in step S22, the controller 130 determines whether the opening of the injection valve 46 is the fully open opening and has continued for more than the first time. When the condition of step S21 is met, the process transfers to step S23, and the controller 130 determines that the refrigerant is insufficient.

[0207] When the refrigerant in the refrigerant circuit 6 is insufficient, sometimes the gaseous refrigerant flows into the subcooling heat exchanger 28, or the gas-liquid two-phase refrigerant with a large dryness flows into the subcooling heat exchanger 28. In particular, when the refrigerant in the refrigerant circuit 6 is insufficient and there is almost no liquid refrigerant in the gas-liquid separator 25, the gaseous refrigerant will flow in the first flow path 28a. In this case, the state where the degree of subcooling of the refrigerant flowing out of the first flow path 28a of the subcooling heat exchanger 28 is low or zero continues. When the above-mentioned degree of subcooling control is performed under this condition, the opening of the injection valve 46 gradually increases, and finally the state where the injection valve 46 becomes fully open will continue. Therefore, when the condition of step S21 is met, the controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient. When it is determined that the refrigerant is insufficient, in step S24, the notification unit 134 issues a notification of insufficient refrigerant. As a result, the subject can quickly know that the refrigerant in the refrigerant circuit 6 is insufficient.

[0208] In step S22, the controller 130 determines whether the opening of the injection valve 46 is greater than the second opening and has continued for a prescribed time (second time) or more. In the present embodiment, the second opening is a prescribed opening that is smaller than the first opening. The second time is a prescribed time that is longer than the first time. That is, when the opening of the injection valve 46 is a second opening that is smaller than the first opening and continues for a second time that is longer than the first time, the condition of step S22 is met. When the condition of step S22 is met, the process transfers to step S23, and the controller 130 determines that the refrigerant is insufficient.

[0209] As described above, when the refrigerant in the refrigerant circuit 6 is insufficient, and the gaseous refrigerant or the gas-liquid two-phase refrigerant with a large dryness flows in the first flow path 28a, the state in which the injection valve 46 is opened at a large degree will continue for a long time due to the supercooling degree control. Therefore, when the condition of step S22 is satisfied, the controller 130 determines that the refrigerant in the refrigerant circuit 6 is insufficient. When it is determined that the refrigerant is insufficient, in step S24, the notification unit 134 issues a notification of insufficient refrigerant.

[0210] (10-3) Technical effect of judging based on the opening degree of the injection valve

[0211] In the subcooling control, as a method for judging whether the refrigerant in the refrigerant circuit 6 is insufficient, it is also possible to consider using the subcooling itself. Specifically, in the subcooling control, when the condition that the subcooling is less than the specified value is satisfied, the controller 130 judges that the refrigerant in the refrigerant circuit 6 is insufficient. However, compared with the opening of the injection valve 46 during the subcooling control, the subcooling is prone to change sharply according to the state of the refrigerant. This is because, as described above, the opening of the injection valve 46 changes according to the addition value or subtraction value of the pulse based on the difference between the subcooling sc and the target subcooling Tsc, and the subcooling sc is an indicator that directly reflects the change in the state of the refrigerant.

[0212] If it is assumed that the refrigerant in the refrigerant circuit 6 is insufficient based on the degree of supercooling, when the state of the refrigerant temporarily changes due to some influence, it may be erroneously determined that the refrigerant in the refrigerant circuit 6 is insufficient. Specifically, for example, when the liquid level in the gas-liquid separator 25 is unstable and the separated gaseous refrigerant temporarily flows out to the first flow path 28a, the degree of supercooling may temporarily be lower than the specified value. In this case, although the refrigerant in the refrigerant circuit 6 is not actually insufficient, it may be erroneously determined that the refrigerant in the refrigerant circuit 6 is insufficient.

[0213] In contrast, in the present embodiment, the opening of the injection valve 46, which changes slowly compared to the degree of supercooling, is used to determine whether the refrigerant in the refrigerant circuit 6 is insufficient. Therefore, it is possible to prevent the erroneous determination that the refrigerant in the refrigerant circuit 6 is insufficient when the gaseous refrigerant temporarily flows in the first flow path 28a due to the above-mentioned reasons or the like.

[0214] (10-4) Other conditions to prevent misjudgment

[0215] In order to prevent misjudgment of the refrigerant circuit 6, the controller 130 does not judge that the refrigerant in the refrigerant circuit 6 is insufficient under the following conditions. The following conditions can be said to be conditions under which the degree of supercooling sc of the refrigerant flowing out of the first flow path 28a is unstable. In other words, the controller 130 judges that the refrigerant in the refrigerant circuit 6 is insufficient under the condition that the degree of supercooling sc is stable.

[0216] Condition a) The controller 130 does not judge that the refrigerant in the refrigerant circuit 6 is insufficient during the period from when the compression unit 20 starts to operate until a predetermined time (15 minutes) has passed. This is because the degree of supercooling sc is not stable during the period from when the compression unit 20 starts to operate until a predetermined time (e.g., 15 minutes) has passed. In other words, the controller 130 judges that the refrigerant in the refrigerant circuit 6 is insufficient after a predetermined time has passed since the compression unit 20 started to operate.

[0217] Condition b) When the outdoor heat exchanger 24 is operated as a radiator, when the outdoor air temperature is higher than a predetermined temperature Ta (e.g., 32° C.), in order to increase the high pressure of the refrigerant circuit 6, the controller 130 controls the opening of the injection valve 46 so that the intermediate pressure of the refrigerant circuit 6 approaches a predetermined target value. Here, the intermediate pressure is detected by the intermediate pressure sensor 102. Under this condition, since the injection valve 46 is not controlled for supercooling, the controller 130 does not judge that the refrigerant in the refrigerant circuit 6 is insufficient.

[0218] Condition c) When the indoor heat exchanger 64 is operated as a radiator, when the outdoor air temperature is lower than a predetermined temperature Tb (e.g., 10° C.), in order to increase the high pressure of the refrigerant circuit 6, the controller 130 controls the opening of the injection valve 46 so that the intermediate pressure of the refrigerant circuit 6 approaches a predetermined target value. Under this condition, since the injection valve 46 is not subjected to supercooling control, the controller 130 does not judge whether the refrigerant in the refrigerant circuit 6 is insufficient.

[0219] Condition d) When the outdoor air temperature is higher than a predetermined temperature (e.g., 32° C.), the high pressure of the refrigerant circuit 6 or the internal pressure of the gas-liquid separator 25 increases, so the controller 130 increases the opening of the exhaust valve 42 or decreases the opening of the first outdoor expansion valve 26. Under such conditions, since the degree of subcooling sc of the refrigerant flowing out of the first flow path 28a is unstable, the controller 130 does not judge that the refrigerant in the refrigerant circuit 6 is insufficient. In other words, when the outdoor air temperature is higher than a predetermined temperature, the high pressure is higher than a predetermined value, or the internal pressure of the gas-liquid separator 25 is higher than a predetermined value, the controller 130 does not judge that the refrigerant in the refrigerant circuit 6 is insufficient.

[0220] Condition e) The controller 130 does not judge whether the refrigerant in the refrigerant circuit 6 is insufficient during the period from the switching time of the above-mentioned various operations to the elapse of the prescribed time. This is because the degree of supercooling sc is not stable during the period from the switching of each operation to the elapse of the prescribed time. In other words, the controller 130 judges whether the refrigerant in the refrigerant circuit 6 is insufficient after the prescribed time has elapsed since the switching of each operation.

[0221] (11) Effects of Implementation

[0222] The controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient, on the condition that the opening degree of the subcooling-side pressure-reducing valve 46 is equal to or greater than a predetermined opening degree.

[0223] When the refrigerant circuit 6 is insufficient, the degree of subcooling of the refrigerant flowing out of the first flow path 28a decreases or becomes zero, and the opening of the subcooling side pressure reducing valve 46 becomes greater than a predetermined opening.

[0224] Since the opening degree of the subcooling-side pressure reducing valve 46 changes more slowly than the subcooling degree itself, it is possible to prevent an erroneous determination that the refrigerant circuit 6 is insufficient.

[0225] In particular, the controller 130 determines that the refrigerant is insufficient on the condition that the opening degree of the subcooling side pressure reducing valve 46 is greater than or equal to a predetermined opening degree and continues for a predetermined time period or longer.

[0226] Therefore, it is possible to further prevent an erroneous determination that the refrigerant in the refrigerant circuit 6 is insufficient.

[0227] The controller 130 determines the refrigerant shortage under the condition that the opening of the subcooling side pressure reducing valve 46 is greater than the first opening and lasts for a first time or more, or the opening of the subcooling side pressure reducing valve 46 is greater than the second opening and lasts for a second time or more. The second time is longer than the first time, and the second opening is smaller than the first opening.

[0228] According to these conditions, when the opening of the subcooling side pressure reducing valve 46 is large, it can be quickly determined that the refrigerant in the refrigerant circuit 6 is insufficient. Even when the opening of the subcooling side pressure reducing valve 46 is small, it can be determined that the refrigerant in the refrigerant circuit 6 is insufficient because this state continues for a long time.

[0229] The controller 130 determines whether the refrigerant in the refrigerant circuit 6 is insufficient, on the condition that the opening degree of the subcooling-side pressure-reducing valve 46 is in the fully open state.

[0230] When the refrigerant in the refrigerant circuit 6 is insufficient, the degree of subcooling of the refrigerant flowing out of the first flow path 28a should become zero, so that the subcooling side pressure reducing valve 46 eventually reaches the maximum opening of the control range. Therefore, by taking the opening of the subcooling side pressure reducing valve 46 as a condition of being in a fully open state, it is possible to accurately determine whether the refrigerant in the refrigerant circuit 6 is insufficient.

[0231] The refrigerant circuit 6 is configured to perform a refrigeration cycle in which the high-pressure pressure reaches a critical pressure or higher. Therefore, the degree of subcooling sc of the refrigerant flowing out of the first flow path 28a is likely to become unstable. In contrast, since the opening of the subcooling-side pressure reducing valve 46 changes slowly compared to the degree of subcooling itself, it is possible to prevent the erroneous judgment that the refrigerant in the refrigerant circuit 6 is insufficient due to the instability of the degree of subcooling sc.

[0232] In the refrigerant circuit 6, a gas-liquid separator 25 is provided between the outdoor heat exchanger 24 and the first flow path 28a of the subcooling heat exchanger 28. Therefore, in the case where the liquid level of the gas-liquid separator 25 is unstable, the gaseous refrigerant may temporarily flow into the first flow path 28a. In contrast, since the opening degree of the subcooling side pressure reducing valve 46 changes slowly compared with the subcooling degree itself, it is possible to prevent the erroneous judgment that the refrigerant in the refrigerant circuit 6 is insufficient due to the instability of the subcooling degree sc.

[0233] (12) Other Implementation Methods

[0234] The controller 130 may determine that the refrigerant in the refrigerant circuit 6 is insufficient when the opening degree of the subcooling-side pressure-reducing valve 46 instantaneously reaches or exceeds a predetermined opening degree.

[0235] When determining that the refrigerant is insufficient, the controller 130 may execute a predetermined control such as stopping the operation of the refrigeration apparatus 1 .

[0236] The compression unit 20 may also be a compressor.

[0237] The injection flow path 43 may also send the refrigerant to the suction side of the compression unit 20 .

[0238] The first utilization side heat exchanger 64 may be a heat exchanger for heating or cooling water, salt water, etc. The first utilization side heat exchanger 64 may be used as a heat source of a water heater.

[0239] The above embodiments and variations are described, but it should be understood that various changes can be made to the scheme or detailed structure without departing from the spirit and scope of the claims. The elements of the above embodiments, variations and other embodiments can also be appropriately combined or replaced.

[0240] The words "first", "second", "third", etc. mentioned above are only used to distinguish sentences containing the above words, and do not limit the quantity and order of the sentences.

[0241] - Industrial Applicability -

[0242] In summary, the present disclosure is useful for heat source units and refrigeration devices.

[0243] - Explanation of symbols -

[0244] 1 Refrigeration unit

[0245] 6 Refrigerant circuit

[0246] 10 Heat source unit

[0247] 20 Compression

[0248] 24 Outdoor heat exchanger (heat source side heat exchanger)

[0249] 25 Gas-Liquid Separator

[0250] 28 Subcooling heat exchanger

[0251] 28a First flow path

[0252] 28b Second flow path

[0253] 46 Injection valve (subcooling side pressure reducing valve)

[0254] 60, 70 units

Claims

1. A heat source unit, characterized in that: The heat source unit comprises a refrigerant circuit (6) and a controller (130). The refrigerant circuit (6) includes a compression unit (20), a heat source side heat exchanger (24), a subcooling side pressure reducing valve (46), and a subcooling side heat exchanger (28), wherein the subcooling side heat exchanger (28) has a first flow path (28a) and a second flow path (28b), wherein the first flow path (28a) is for the refrigerant that has released heat in the heat source side heat exchanger (24) to flow, and the second flow path (28b) is for the refrigerant that has passed through the first flow path (28a) and has been pressure-reduced by the subcooling side pressure reducing valve (46) to flow. The controller (130) controls the subcooling-side pressure reducing valve (46) according to the degree of subcooling of the refrigerant flowing out of the first flow path (28a) of the subcooling heat exchanger (28). The controller (130) determines that the refrigerant in the refrigerant circuit (6) is insufficient based on the fact that the opening degree of the subcooling-side pressure reducing valve (46) has increased.

2. The heat source unit according to claim 1, characterized in that: The controller (130) determines whether the refrigerant in the refrigerant circuit (6) is insufficient, based on the condition that the opening degree of the subcooling side pressure reducing valve (46) is greater than a predetermined opening degree.

3. The heat source unit according to claim 2, characterized in that: The controller (130) determines that the refrigerant is insufficient on the condition that the opening degree of the subcooling side pressure reducing valve (46) is greater than the predetermined opening degree and lasts for more than a predetermined time.

4. The heat source unit according to claim 3, characterized in that: The controller (130) determines the refrigerant shortage based on the condition that the opening degree of the subcooling side pressure reducing valve (46) is greater than a first opening degree and lasts for a first time or more, or the opening degree of the subcooling side pressure reducing valve (46) is greater than a second opening degree and lasts for a second time or more. the second time is longer than the first time, The second opening degree is smaller than the first opening degree.

5. The heat source unit according to any one of claims 1 to 3, characterized in that: The controller (130) determines whether the refrigerant in the refrigerant circuit (6) is insufficient, based on the condition that the opening degree of the subcooling side pressure reducing valve (46) is in a fully open state.

6. The heat source unit according to any one of claims 1 to 5, characterized in that: The refrigerant circuit (6) is configured to be capable of performing a refrigeration cycle in which the high-pressure pressure reaches a critical pressure or higher.

7. The heat source unit according to any one of claims 1 to 6, characterized in that: In the refrigerant circuit (6), a gas-liquid separator (25) is provided between the heat source side heat exchanger (24) and the first flow path (28a) of the subcooling heat exchanger (28).

8. A refrigeration device, characterized in that: The refrigeration device comprises: a heat source unit (10) as claimed in any one of claims 1 to 7, and a utilization unit (60, 70).

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