Refrigeration device

Abstract

To provide refrigeration equipment to which a plurality of types of external equipment can be easily connected.SOLUTION: Refrigeration equipment comprises a refrigeration circuit to which a plurality of compressors, a heat source-side heat exchanger, a gas-liquid separator, and a plurality of utilization-side heat exchangers are connected. Each of the plurality of compressors is composed of a low- stage compressor and a high-stage compressor. Each of the plurality of utilization-side heat exchangers is composed of a first utilization-side heat exchanger and a second utilization-side heat exchanger having a refrigerant evaporation temperature lower than that of the first utilization-side heat exchanger. The first utilization-side heat exchanger is connected to the high-stage compressor, and the second utilization-side heat exchanger is connected to the low-stage compressor. Throttle mechanisms are provided between the gas-liquid separator, and the heat source-side heat exchanger and the first utilization-side heat exchanger. A first service valve is disposed on the upstream side of the throttle mechanism.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to refrigeration devices. [Background technology]

[0002] Patent Document 1 discloses a method for safely replacing a refrigerant in a refrigeration cycle that uses a flammable refrigerant as the operating refrigerant. In this method, after recovering the refrigerant, a service valve is connected to the refrigeration cycle, and the refrigerant is evacuated and recharged through the service valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-160295 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a refrigeration apparatus to which multiple types of external devices can be easily connected. [Means for solving the problem]

[0005] The refrigeration device of the present disclosure includes a refrigeration circuit connecting a plurality of compressors, a heat source side heat exchanger, a gas-liquid separator, and a utilization side heat exchanger, the plurality of compressors being composed of a low stage compressor and a high stage compressor, and includes a throttling mechanism between the gas-liquid separator, the heat source side heat exchanger, and the utilization side heat exchanger, a first service valve being arranged upstream of the throttling mechanism, and a second service valve being arranged downstream of the throttling mechanism. Effect of the Invention

[0006] According to the present disclosure, multiple types of external devices can be easily connected. [Brief description of the drawings]

[0007] [Figure 1] A circuit diagram of a refrigeration device showing the operation during cooling operation in embodiment 1. [Diagram 2] FIG. 1 is a schematic side view showing a humidity control device (external device) according to a first embodiment. [Diagram 3] FIG. 1 is a schematic front view showing a humidity control device (external device) according to a first embodiment. [Figure 4] A circuit diagram of a refrigeration device showing the operation during heating operation in embodiment 1. [Diagram 5] A circuit diagram of a refrigeration device showing the operation of a heating operation when the amount of heat absorbed by the cooling equipment in the first embodiment is insufficient. [Figure 6] A circuit diagram of a refrigeration device showing the operation when a large capacity is required and a heating amount is not required in the cooling equipment in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (The knowledge and other information that formed the basis of this disclosure) At the time when the inventors arrived at the present disclosure, there was a technique for safely replacing a refrigerant in a refrigeration system equipped with a refrigeration cycle using a flammable refrigerant as the working refrigerant. In this refrigerant replacement method, when replacing the refrigerant, after recovering the refrigerant, a pump for vacuuming and a refrigerant cylinder for charging the refrigerant are connected to the refrigeration cycle via a service valve, and the refrigerant is vacuumed and recharged. In such a refrigeration system, external devices such as a refrigerant recovery device and a humidity control unit are connected via a connecting device that is different from the service valve.

[0009] The inventors discovered that this refrigeration system requires an increased number of parts for connecting external equipment, which increases costs and may complicate the work involved in connecting external equipment. In order to solve this problem, they came up with the subject matter of the present disclosure. The present disclosure provides a refrigeration apparatus to which multiple types of external devices can be easily connected.

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to the drawings. [1-1-1. Configuration of refrigeration equipment] Fig. 1 is a diagram showing a refrigeration circuit of a refrigeration device 1 in the first embodiment. For ease of explanation, in Fig. 1, a valve body in an open state is shown in white, and a valve body in a closed state and an expansion mechanism are shown in black. In Fig. 1, an external device 405 and a pipe connecting the external device to the refrigeration circuit are shown by a two-dot chain line. For ease of explanation, in Fig. 1, a pipe through which a refrigerant flows is shown by a thick line, and a pipe through which a refrigerant does not flow is shown by a thin line. The refrigeration circuit uses carbon dioxide (R744), a natural refrigerant that is non-flammable and non-toxic. As shown in FIG. 1, the refrigeration system 1 includes an outdoor unit 10, an indoor unit 20, and a cooling device 30. The indoor unit 20 provides air conditioning within a store, such as a convenience store or supermarket, and the refrigeration equipment 30 provides cooling within refrigerated showcases and freezer showcases as cooling storage facilities installed within the store.

[0012] The refrigeration system 1 includes an outdoor unit 10 that is configured by sequentially connecting a two-stage compressor including a low-stage compressor 11 and high-stage compressors 12, 12, a first switching mechanism 50, an outdoor heat exchanger 15, a second switching mechanism 54, and a gas-liquid separator 16. The two high-stage compressors 12, 12 are connected in parallel to the low-stage compressor 11. An accumulator 13 is disposed between the low-stage compressor 11 and the high-stage compressor 12. The refrigerant discharged from the low-stage compressor 11 is separated into gas and liquid by the accumulator 13, and the gas refrigerant is sent to the high-stage compressor 12.

[0013] An oil separator 14 is connected to the discharge downstream side of the high stage compressor 12. A first switching mechanism 50 is connected to the oil separator 14, and an outdoor heat exchanger 15 is connected to the first switching mechanism 50. The first switching mechanism 50 includes a pipe 40 that connects the oil separator 14 and the outdoor heat exchanger 15, and a first cooling valve (first on-off valve) 51 is connected to the pipe 40. In the piping 40, a first heating piping 41 is connected to the upstream side of the first cooling valve 51. The first heating piping 41 is equipped with a first heating valve 52 (second on-off valve). The first heating piping 41 is connected to a piping 71 that connects the indoor heat exchanger 22 of the indoor unit 20 and the suction side of the high-stage compressor 12. An on-off valve 23 is connected to the piping 71.

[0014] In the piping 40, a first outdoor return piping 42 is connected to the downstream side of the first cooling valve 51. The first outdoor return piping 42 is equipped with an outdoor refrigerant return valve (third on-off valve) 53. The first outdoor return piping 42 is connected to a piping 72 that connects the cooling-use heat exchanger 31 of the cooling equipment 30 and the suction side of the low-stage compressor 11, and the piping 72 is connected to a cooling-use outlet-side pressure adjustment mechanism 33 of the cooling equipment 30.

[0015] A second switching mechanism 54 is connected to the exterior heat exchanger 15, and a gas-liquid separator 16 is connected to the second switching mechanism 54. The second switching mechanism 54 is formed by connecting the ends of the first to fourth pipes 73, 74, 75, and 76 at connection parts A, B, C, and D in a ring shape. A second cooling valve (first control valve) 55 and a check valve 59 are disposed in the first pipe 73, a refrigerant return expansion mechanism (second control valve) 58 that controls the flow rate is disposed in the second pipe 74, and a third cooling valve (third control valve) 56 and a check valve 59 are disposed in the third pipe 75. In addition, a second heating valve (fourth control valve) 57 and a check valve 59 are disposed in the fourth pipe 76.

[0016] A connection part A between the second cooling valve 55 and the refrigerant return expansion mechanism 58 is connected to the outdoor heat exchanger 15, and a connection part B between the refrigerant return expansion mechanism 58 and the third cooling valve 56 is connected to a pipe 77 that connects the gas-liquid separator 16 and the cooling set heat exchanger 31. The cooling set inlet side expansion mechanism 32 is connected to this pipe 77. A connection part C between the third cooling valve 56 and the second heating valve 57 is connected to the indoor heat exchanger 22 via a pipe (second cooling pipe) 78. The second cooling pipe 43 is connected to the indoor expansion mechanism 21 of the indoor unit 20. A connection part D between the second heating valve 57 and the second cooling valve 55 is connected to the gas-liquid separator 16 via a pipe 79. In the pipe 79, a throttle mechanism 17 is arranged.

[0017] As described above, the indoor heat exchanger 22 is a utilization-side heat exchanger provided in the indoor unit 20. When the indoor unit 20 performs cooling operation, the indoor heat exchanger 22 functions as an evaporator, and the evaporation temperature is determined by the opening degree of the indoor expansion mechanism 21. In the present embodiment, the evaporation temperature of the indoor heat exchanger 22 is determined according to the indoor temperature set in the indoor unit 20. The evaporation temperature zone of the indoor heat exchanger 22 is, for example, 3°C to 6°C.

[0018] As described above, the cold-setting heat exchanger 31 is a user-side heat exchanger provided in the cold-setting equipment 30. The cold-setting heat exchanger 31 functions as an evaporator, and the evaporation temperature is determined by the opening degree of the cold-setting inlet-side expansion mechanism 32. In this embodiment, the evaporation temperature of the cold-setting heat exchanger 31 is determined according to the internal temperature set in the cold-setting equipment 30.

[0019] The refrigeration equipment 30 of the present embodiment can select and set the temperature zone within the refrigerator to, for example, either a partial temperature zone (-3°C to -1°C) or a freezing temperature zone (-20°C to -18°C).

[0020] When the temperature zone inside the refrigerator is the partial temperature zone, the evaporation temperature zone of the refrigeration heat exchanger 31 is, for example, -12°C to 0°C. Specifically, when the refrigeration equipment 30 stores fruits and vegetables, the evaporation temperature zone of the refrigeration heat exchanger 31 is, for example, -5°C to 0°C. When the refrigeration equipment 30 stores meat or fresh fish, the evaporation temperature zone of the refrigeration heat exchanger 31 is, for example, -12°C to -8°C. When the temperature zone inside the storage unit is the freezing temperature zone, the evaporation temperature zone of the cooling heat exchanger 31 is, for example, from -40°C to -20°C. Therefore, the evaporation temperature zone of the cold-installed heat exchanger 31 is set lower than the temperature zone inside the storage unit.

[0021] In this way, two utilization-side heat exchangers with different evaporation temperature zones are provided in the refrigeration system 1. Of these two utilization-side heat exchangers with different evaporation temperature zones, the indoor heat exchanger 22 is connected to the inlet side of the high-stage compressor 12, and the cold-use heat exchanger 31, which has a lower evaporation temperature zone than the indoor heat exchanger 22, is connected to the inlet side of the low-stage compressor 11. The indoor heat exchanger 22 corresponds to a "first use-side heat exchanger" in the present disclosure, and the cold-use heat exchanger 31 corresponds to a "second use-side heat exchanger" in the present disclosure.

[0022] A gas refrigerant return pipe 60 is connected to the gas-liquid separator 16, and the gas refrigerant return pipe 60 is connected to a pipe 71 and connected to the accumulator 13. A gas refrigerant flow rate control valve 61 is connected to the gas refrigerant return pipe 60. In this embodiment, a portion of the gas refrigerant separated in the gas-liquid separator 16 has its flow rate adjusted by the gas refrigerant flow control valve 61, is sent to the accumulator 13, and is returned to the suction side of the high-stage compressor 12.

[0023] In the refrigeration system 1, by controlling the opening of the gas refrigerant flow control valve 61 and adjusting the return amount of the gas refrigerant, the refrigerant pressure is made higher on the inlet side of the indoor expansion mechanism 21 than on the outlet side of the indoor heat exchanger 22. That is, in the refrigeration system 1, it is possible to generate a refrigerant pressure difference between the inlet side and outlet side of the indoor heat exchanger 22 in the refrigeration circuit.

[0024] As a result, in the refrigeration system 1, in the indoor heat exchanger 22 where the evaporation temperature of the refrigerant is high, it is possible to control the refrigerant flowing through the indoor heat exchanger 22 at a pressure value obtained by adding a specified pressure value to the pressure value at which the refrigerant evaporates. Therefore, in the refrigeration system 1, carbon dioxide (R744), a natural refrigerant with high environmental friendliness, is used, which can improve the efficiency of the air conditioning temperature range and can improve the efficiency of the entire refrigeration system.

[0025] [1-1-2. Configuration for connecting external equipment to a refrigeration unit] In the first embodiment, the throttling mechanism 17 is connected between the second switching mechanism 54 and the gas-liquid separator 16. The throttling mechanism 17 is provided in the piping 79. In the piping 79, a first service valve 401 is disposed upstream of the throttling mechanism 17, and a second service valve 402 is disposed downstream of the throttling mechanism 17.

[0026] The first service valve 401 has three connection ports. One is an external connection port 500 that can connect a vacuum drawing unit, a refrigerant sealing unit, and an external device 405, and of the remaining two connection ports, one connection port is connected to connection part D of the second switching mechanism 54, and the other connection port is connected to the throttling mechanism 17. The second service valve 402 has three ports. One is an external connection port 500 that can connect a vacuum drawing unit, a refrigerant sealing unit, and an external device 405, and of the remaining two connection ports, one connection port is connected to a throttling mechanism 17 and the other connection port is connected to a gas-liquid separator 16.

[0027] Each service valve 401, 402 is connected in one of the following forms: a form in which the external connection port 500 is blocked and the remaining two connection ports are connected; a form in which all three connection ports including the external connection port 500 are connected; or a form in which the external connection port 500 is connected to one of the remaining two connection ports.

[0028] As described above, the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402 are formed so as to be connectable to a vacuum unit, a refrigerant sealing unit, and multiple types of external devices 405.

[0029] The vacuum unit is a unit capable of performing a vacuum operation, which is an operation of discharging air from piping included in the refrigeration circuit of the refrigeration device 1. The vacuum unit includes, for example, piping such as a hose connectable to the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402, a valve body capable of opening and closing the hose, and a vacuum pump connected to the hose.

[0030] A refrigerant sealing unit can be connected to the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402 as a post-installation, instead of the above-mentioned vacuum unit. The refrigerant sealing unit is a unit that seals refrigerant in the refrigeration circuit of the refrigeration device 1. The refrigerant sealing unit includes, for example, piping such as a hose that can be connected to the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402, a valve body that can open and close the hose, and a refrigerant cylinder that is connected to the hose.

[0031] Furthermore, instead of the above-mentioned vacuum unit and refrigerant charging unit, a refrigerant recovery unit can be connected later as external equipment 405 to external connection port 500 of first service valve 401 and external connection port 500 of second service valve 402. The refrigerant recovery unit is a unit that recovers refrigerant from the refrigeration circuit of refrigeration device 1. The refrigerant charging unit includes, for example, piping such as a hose connectable to external connection port 500 of first service valve 401 and external connection port 500 of second service valve 402, a valve body that can open and close the hose, a refrigerant tank connected to the hose, and a refrigerant recovery machine.

[0032] Between the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402, an external device 405 can be connected in parallel to the throttle mechanism 17. An example of this external device 405 is the humidity control device 450 shown in Figs. 2 and 3.

[0033] Fig. 2 is a schematic side view showing an embodiment of a humidity control device, and Fig. 3 is a schematic front view showing an embodiment of a humidity control device 450. 2 and 3, humidity control device 450 includes heating heat exchanger 406, cooling / dehumidifying heat exchanger 407, and blower 408. Blower 408 is a device that causes air to flow through cooling / dehumidifying heat exchanger 407 and heating heat exchanger 406 in that order. Arrow X1 in Fig. 2 indicates the air flow direction. A refrigerant pipe 410 is connected to the refrigerant inlet side of the heating heat exchanger 406. A throttle mechanism 411 is provided in the middle of the refrigerant pipe 410. The refrigerant outlet side of the heating heat exchanger 406 and the refrigerant inlet side of the cooling and dehumidifying heat exchanger 407 are connected by a refrigerant pipe 412, and a throttle mechanism 413 is provided in the middle of this refrigerant pipe 412.

[0034] A drain pan 415 for storing condensation water is installed below the heating heat exchanger 406 and the cooling and dehumidifying heat exchanger 407. The drain pan 415 is inclined downward from the cooling and dehumidifying heat exchanger 407 toward the heating heat exchanger 406, and is configured to store the condensation water in a state where it has been heated by the heating heat exchanger 406. A drain pipe 416 for draining condensed water is provided below the drain pan 415, and a drain control valve 417 is provided in the drain pipe 416. An evaporation sheet 418 that sucks up condensed water stored in a drain pan 415 is disposed downstream of the heating heat exchanger 406 .

[0035] A humidity sensor 419 is provided near the cooling and dehumidifying heat exchanger 407 to detect the humidity of the air flowing into the cooling and dehumidifying heat exchanger 407. Based on the detection result of the humidity sensor 419, the opening degree of the throttling mechanism 411 of the heating heat exchanger 406 and the throttling mechanism 413 of the cooling and dehumidifying heat exchanger 407 are adjusted. The drain pan 415 is equipped with a sterilization device 420 that sterilizes the condensed water stored in the drain pan 415. As the sterilization device 420, for example, an electrostatic atomization device or the like is used.

[0036] The humidity control device 450 can be installed at any location in the room where dehumidification is desired. For example, in convenience stores, condensation occurs on the ceiling due to radiant heat from flat showcases with open tops, causing mold growth. In this case, the humidity control device 450 is installed so that it can blow air toward the ceiling of the space to be conditioned.

[0037] [1-2. Operation and Effects] Next, the operation of this embodiment will be described.

[0038] [1-2-1. Cooling operation] First, the cooling operation will be described. During cooling operation, as shown in FIG. 1, the outdoor heat exchanger 15 is used as a gas cooler or a radiator, and the indoor heat exchanger 22 and the cold-setting heat exchanger 31 are used as evaporators. When performing cooling operation, the first switching mechanism 50 opens the first cooling valve 51 and closes the remaining first heating valve 52 and outdoor refrigerant return valve 53. The second switching mechanism 54 opens the second cooling valve 55 and the third cooling valve 56 and closes the second heating valve 57 and the refrigerant return expansion mechanism 58. In this state, by driving the low-stage compressor 11 and each high-stage compressor 12, the refrigerant compressed by the low-stage compressor 11 is sent to each high-stage compressor 12, further compressed by each high-stage compressor 12, and discharged toward the oil separator 14.

[0039] The refrigerant that has passed through the oil separator 14 is sent to the outdoor heat exchanger 15 through the first cooling valve 51 of the first switching mechanism 50, and exchanges heat with outside air in the outdoor heat exchanger 15. The refrigerant after heat exchange is sent from connection part A of the second switching mechanism 54 to the gas-liquid separator 16 via the second cooling valve 55. The refrigerant separated in the gas-liquid separator 16 passes through piping 77 to reach connection part B of the second switching mechanism 54. One of the refrigerants branched at connection part B is sent to the indoor heat exchanger 22 via the third cooling valve 56 and the indoor expansion mechanism 21 of the indoor unit 20. In the indoor heat exchanger 22, the refrigerant exchanges heat with the indoor air to cool the indoor air. The refrigerant that has exchanged heat with the indoor air passes through the pipe 71 and is returned to the suction side of each high-stage compressor 12 via the on-off valve 23 and the accumulator 13.

[0040] The other refrigerant branched off at the connection part B is sent to the refrigeration heat exchanger 31 via the refrigeration inlet side expansion mechanism 32 of the refrigeration equipment 30, and undergoes heat exchange in the refrigeration heat exchanger 31 to cool the refrigeration equipment 30. The refrigerant that has exchanged heat in the refrigeration heat exchanger 31 is returned to the low-stage compressor 11 via the refrigeration outlet side pressure adjustment mechanism 33.

[0041] [1-2-2. Heating operation] Next, an operation when the first heating operation (heating operation) is performed will be described. 4 is a circuit diagram of the refrigeration device 1 showing the operation of the heating mode, in which the flow of the refrigerant is indicated by arrows. The first heating operation is performed with the indoor heat exchanger 22 functioning as a gas cooler or a radiator, and the cooling heat exchanger 31 functioning as an evaporator. 4, when performing heating operation, the first switching mechanism 50 opens the first heating valve 52 and closes the remaining first cooling valve 51 and outdoor refrigerant return valve 53. In addition, the second switching mechanism 54 opens the second heating valve 57 and closes the second cooling valve 55, the third cooling valve 56, and the refrigerant return expansion mechanism 58.

[0042] In this state, by driving the low-stage compressor 11 and each high-stage compressor 12, the refrigerant compressed by the low-stage compressor 11 is sent to each high-stage compressor 12, further compressed by each high-stage compressor 12, and discharged toward the oil separator 14. The refrigerant that has passed through the oil separator 14 passes through the first heating valve 52 of the first switching mechanism 50 and is sent to the indoor heat exchanger 22, where it exchanges heat with the indoor air, heating the indoor air.

[0043] The refrigerant that has exchanged heat in the indoor heat exchanger 22 passes through the indoor expansion mechanism 21, reaches the connection part C of the second switching mechanism 54, and is sent to the gas-liquid separator 16 via the second heating valve 57. The refrigerant separated in the gas-liquid separator 16 passes through the piping 77, reaches the connection part B of the second switching mechanism 54, and is sent to the cold-setting heat exchanger 31 via the cold-setting inlet-side expansion mechanism 32. This refrigerant exchanges heat in the cold-setting heat exchanger 31, and cools the cold-setting equipment 30. The refrigerant that has exchanged heat in the cold-setting heat exchanger 31 passes through the pipe 72 and is returned to the suction side of the low-stage compressor 11 via the cold-setting outlet side pressure adjustment mechanism 33. In the refrigeration device 1 of the present disclosure, during heating, the indoor heat exchanger 22 functions as a gas cooler or a radiator, and the outdoor heat exchanger 15 is not used.

[0044] [1-2-3. Operation when the heat absorption by cooling equipment is insufficient] Next, an explanation will be given of the operation of performing the second heating operation at full capacity when the amount of heat absorbed by the cooling equipment 30 is insufficient, for example, when the outside air temperature is lower than the temperature inside the cooling equipment 30. Fig. 5 is a circuit diagram of the refrigeration device 1 showing the operation of the heating operation when the amount of heat absorbed by the cooling equipment is insufficient. The flow of the refrigerant is indicated by arrows in the figure. The second heating operation is performed with the indoor heat exchanger 22 functioning as a gas cooler or a radiator, and the cooling-set heat exchanger 31 and the outdoor heat exchanger 15 functioning as evaporators. When the second heating operation is performed at full capacity, the first switching mechanism 50 opens the first heating valve 52 and the outdoor refrigerant return valve 53, and closes the first cooling valve 51. The second switching mechanism 54 opens the second heating valve 57 and the refrigerant return expansion mechanism 58, and closes the second cooling valve 55 and the third cooling valve 56.

[0045] In this state, by driving the low-stage compressor 11 and each high-stage compressor 12, the refrigerant compressed by the low-stage compressor 11 is sent to each high-stage compressor 12, further compressed by each high-stage compressor 12, and discharged toward the oil separator 14. The refrigerant that has passed through the oil separator 14 is sent to the indoor heat exchanger 22 through the first heating valve 52 of the first switching mechanism 50, and exchanges heat with the indoor air in the indoor heat exchanger 22, heating the indoor air.

[0046] The refrigerant that has exchanged heat in the indoor heat exchanger 22 is sent to the gas-liquid separator 16 via the second heating valve 57 of the second switching mechanism 54. The refrigerant separated in the gas-liquid separator 16 reaches the connection part B of the second switching mechanism 54 through the piping 77. One of the refrigerants branched at the connection part B is sent to the outdoor heat exchanger 15 via the refrigerant return expansion mechanism 58 and the connection part A of the second switching mechanism 54, and exchanges heat with the outside air in the outdoor heat exchanger 15. The other refrigerant branched at the connection part B is sent to the cold-setting heat exchanger 31 via the cold-setting inlet side expansion mechanism 32, and exchanges heat in the cold-setting heat exchanger 31 to cool the cold-setting equipment 30. The refrigerant that has exchanged heat in the cold-setting heat exchanger 31 and the refrigerant that has exchanged heat in the outdoor heat exchanger 15 and is sent from the first outdoor return piping 42 are joined at the piping 72 and returned to the suction side of the low-stage compressor 11.

[0047] The refrigerant that has exchanged heat in the refrigeration heat exchanger 31 is adjusted by the refrigeration outlet pressure adjustment mechanism 33 so that its pressure is the same as that of the refrigerant sent from the first outdoor return pipe 42. This is the operation when the outside air temperature is lower than the temperature inside the refrigeration equipment 30.

[0048] This allows the heat absorption by the cooling heat exchanger 31 and the heat pumped up by the outdoor heat exchanger 15 to be used as heat for the indoor heat exchanger 22, making it possible to increase the heating capacity when the heat absorption by the cooling equipment 30 is insufficient.

[0049] In this case, if the outdoor air temperature becomes lower than the temperature inside the cooling equipment 30, the evaporation temperature of the cooling equipment 30 must be lowered in order to pump heat from the outdoor heat exchanger 15. If the evaporation temperature of the cooling equipment 30 is lowered, it will become lower than the specified temperature, shortening the thermo cycle and resulting in short-cycle operation, which may further reduce the operating efficiency and increase power consumption. In this embodiment, by controlling the opening degree of the cooling outlet side pressure adjustment mechanism 33, it is possible to balance the pressure with the refrigerant sent from the outdoor heat exchanger 15, thereby avoiding the above-mentioned inconvenience.

[0050] [1-2-4. Operation when large capacity is required for cooling equipment and no heating heat is required] Next, an operation when a large capacity is required in the cooling equipment 30 and a heating heat amount is not required will be described. Fig. 6 is a circuit diagram of the refrigeration device 1 showing the operation when a heating heat amount is not required. The flow of the refrigerant is indicated by arrows in the figure. As shown in FIG. 6, the third heating operation is performed with the outdoor heat exchanger 15 and the indoor heat exchanger 22 functioning as gas coolers or radiators, and the cooling heat exchanger 31 functioning as an evaporator. When the third heating operation is performed, the first switching mechanism 50 opens the first cooling valve 51 and the first heating valve 52, and closes the outdoor refrigerant return valve 53. The second switching mechanism 54 opens the second cooling valve 55 and the second heating valve 57, and closes the third cooling valve 56 and the refrigerant return expansion mechanism 58.

[0051] In this state, by driving the low-stage compressor 11 and each high-stage compressor 12, the refrigerant compressed by the low-stage compressor 11 is sent to each high-stage compressor 12, further compressed by each high-stage compressor 12, and discharged toward the oil separator 14.

[0052] The refrigerant that has passed through the oil separator 14 is sent to the outdoor heat exchanger 15 through the first cooling valve 51 of the first switching mechanism 50, and at the same time, sent to the indoor heat exchanger 22 through the first heating valve 52. The outdoor heat exchanger 15 and the indoor heat exchanger 22 function as a gas cooler or a radiator, and exchange heat with outdoor air in the outdoor heat exchanger 15, and exchange heat with indoor air in the indoor heat exchanger 22, thereby heating the indoor air. The refrigerant that has exchanged heat in the outdoor heat exchanger 15 reaches the second cooling valve 55 from the connection part A of the second switching mechanism 54, and the refrigerant that has exchanged heat in the indoor heat exchanger 22 reaches the second heating valve 57 from the connection part C of the second switching mechanism 54, where they are joined and sent to the gas-liquid separator 16. The refrigerant separated in the gas-liquid separator 16 is sent through the pipe 77 to the cold-setting heat exchanger 31, where it undergoes heat exchange to cool the cold-setting equipment 30. The refrigerant that has exchanged heat in the cold-setting heat exchanger 31 is returned to the suction side of the low-stage compressor 11 via the cold-setting outlet-side pressure adjustment mechanism 33.

[0053] According to this, during heating operation, the heat absorbed by the cooling equipment 30 can be dissipated by the outdoor heat exchanger 15 and the indoor heat exchanger 22, the cooling capacity of the cooling equipment 30 can be increased, and frost adhering to the outdoor heat exchanger 15 can be removed.

[0054] [1-2-5. Operation of the refrigeration unit when an external device is connected] As described above, in the refrigeration apparatus 1, the external device 405 can be connected to the external connection port 500 of the first service valve 401 and the external connection port 500 of the second service valve 402. When the external device 405 is not connected, as shown in Fig. 1, the external connection port 500 of each of the service valves 401, 402 is shut off and the other two connection ports are connected.

[0055] [1-2-5-1. Vacuum drawing] When the refrigeration apparatus 1 is newly installed or when the refrigerant in the refrigeration apparatus 1 is replaced, the refrigeration apparatus 1 is subjected to a vacuum drawing operation.

[0056] When this vacuuming operation is performed, the external connection port 500 of either of the service valves 401, 402 is opened and the other two connection ports are blocked. In this state, a vacuuming unit is connected to the opened external connection port 500. Then, in either of the service valves 401, 402 to which the vacuuming unit is connected, the connection ports other than the external connection port 500 are opened. Then, the vacuum pump is driven to vacuum the refrigeration device 1. When the vacuuming is completed, the connection ports other than the external connection port 500 are blocked and the vacuuming unit is removed from the external connection port 500. This makes it possible to fill the refrigeration device 1 with refrigerant.

[0057] [1-2-5-2. Refrigerant filling] In the refrigeration device 1, the refrigerant is sealed or filled, for example, when the refrigerant inside the refrigeration device 1 is drained to repair or replace the refrigeration circuit, or when the amount of refrigerant is insufficient, as described above.

[0058] When a refrigerant charging unit is connected to the service valve 401 during refrigerant charging work, the external connection port 500 and the connection port located on the throttling mechanism 17 side of the other two connection ports are opened in the refrigeration device 1. In this case, the connection port located on the second switching mechanism 54 side of the other two connection ports in the service valve 401 is closed.

[0059] When a refrigerant charging unit is connected to the service valve 402 during refrigerant charging work, the external connection port 500 and the connection port located on the gas-liquid separator 16 side of the other two connection ports are opened in the refrigeration device 1. In this case, the connection port located on the throttling mechanism 17 side of the other two connection ports in the service valve 402 is closed.

[0060] Thereafter, in the refrigeration device 1, with the low stage compressor 11 and the high stage compressor 12 stopped, the refrigerant from the refrigerant charging unit is charged into the refrigeration circuit by utilizing the pressure difference between the pressure of the refrigerant charging unit and the internal pressure of the refrigeration circuit provided in the refrigeration device 1. This allows the refrigerant sent out from the refrigerant charging unit to flow directly into the gas-liquid separator 16 and be stored therein.

[0061] When the pressure difference between the pressure in the refrigeration circuit provided in the refrigeration device 1 and the pressure of the refrigerant charging unit disappears, the refrigerant in the refrigerant charging unit is no longer sent to the refrigeration circuit. In this case, one of the service valves 401, 402 to which the refrigerant charging unit is connected opens the external connection port 500 and the other two connection ports. Then, in the refrigeration device 1, the operation of the low stage compressor 11 and the high stage compressor 12 is resumed to fill the refrigerant in the refrigeration circuit. When the charging of the refrigerant is completed, the connection ports other than the external connection port 500 are shut off, and the refrigerant charging unit is removed from the external connection port 500.

[0062] [1-2-5-3. Refrigerant recovery] As described above, in the refrigeration apparatus 1, when the refrigeration circuit is repaired, replaced, or the like, a refrigerant recovery operation is performed to recover the refrigerant inside the refrigeration apparatus 1.

[0063] In this refrigerant recovery operation, first, in the first service valve 401, the external connection port 500 is opened and the other two connection ports are blocked. In this state, a refrigerant recovery unit is connected to the external connection port 500 of the service valve 401. After that, in the service valve 401, the connection ports other than the external connection port 500 are opened.

[0064] In the refrigeration device 1, the two-stage compressor is driven with the throttling mechanism 17 closed. When the two-stage compressor is driven, as shown in FIG. 1, the refrigerant flows through the gas-liquid separator 16, the second switching mechanism 54, the indoor heat exchanger 22, and the cold-setting heat exchanger 31 in this order, and is sucked into the two-stage compressor. Thereafter, the refrigerant is discharged from the two-stage compressor, passes through the outdoor heat exchanger 15 and the second switching mechanism 54 in this order, and is recovered in the refrigerant recovery unit. When the recovery of the refrigerant is completed, the connection ports other than the external connection port 500 are blocked, and the refrigerant recovery unit is removed from the external connection port 500. This allows the refrigeration device 1 to be vacuumed, filled with refrigerant, or have the refrigeration circuit maintained.

[0065] In addition, in the refrigerant recovery operation, in the refrigeration device 1, the two-stage compressor may be driven in a state in which the connection port connected to the connection part D of the second switching mechanism 54 is closed, instead of the throttling mechanism 17. Also, for example, the refrigerant recovery unit may be connected to the service valve 402.

[0066] In this way, in the refrigeration device 1, by connecting multiple types of external devices 405 to the service valves 401, 402 to which the vacuum unit and the refrigerant sealing unit can be connected, it is possible to recover refrigerant and adjust the humidity in a specified space. That is, in the refrigeration device 1, the service valves 401, 402 are shared as connection parts for a plurality of types of external devices 405 with different uses. Therefore, in the refrigeration device 1, an increase in the number of parts related to the connection of the external devices 405 is suppressed, and the structure of the refrigeration device 1 can be simplified. And, in the refrigeration device 1, the work related to the connection of the external devices 405 can be simplified.

[0067] (Other embodiments) As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create new embodiments.

[0068] In the embodiment described above, the humidity control device 450 and the refrigerant recovery unit are described as external devices 405 connectable to the refrigeration device 1 via the first service valve 401 and the second service valve 402. However, the external device 405 is not limited thereto, and may be, for example, an external cooling device. The external cooling device is a device that includes a heat exchanger and increases the cooling capacity of at least one of the heat exchangers included in the refrigeration device 1, such as the outdoor heat exchanger 15, the indoor heat exchanger 22, and the cold-use heat exchanger 31, by being connected to the refrigeration device 1.

[0069] Furthermore, for example, the external device 405 may be a refrigerant flow rate adjustment device. This refrigerant flow rate adjustment device is a device that includes a storage unit such as a tank capable of storing a refrigerant or a heat exchanger, and is capable of adjusting the flow rate of the refrigerant in the refrigeration device 1 according to an increase or decrease in the cooling capacity of the refrigeration device 1 by storing the refrigerant flowing through the refrigeration device 1.

[0070] Furthermore, for example, the first service valve 401 and the second service valve 402 may be provided with joints connectable to a plurality of types of external devices 405 having different uses. This joint is, for example, a Tee joint. When the joint is provided on at least one of the first service valve 401 and the second service valve 402, a plurality of external devices 405 can be connected to the refrigeration device 1 via the joint. Thereby, for example, a refrigerant recovery unit can be connected to the refrigeration apparatus 1 in a state where the humidity control apparatus 450 is connected as the external device 405. Therefore, in the refrigeration apparatus 1, in a state where the external device 405 such as the humidity control apparatus 450 is driven, other external device 405 can be driven to, for example, charge additional refrigerant.

[0071] Also, for example, in the external device 405, the connection portion connectable to the first service valve 401 and the second service valve 402 may be formed so that another external device 405 can be connected thereto.

[0072] Also, for example, when the external device 405 is connected, the first service valve 401 and the second service valve 402 may be in a state in which the external connection port 500 and the other two connection ports are always open. This allows the refrigeration device 1 to suppress liquid expansion of the refrigerant in the refrigeration circuit.

[0073] In the above-described embodiment, the refrigeration system 1 includes one indoor heat exchanger 22 and one cold-use heat exchanger 31. However, the present invention is not limited to this, and the refrigeration system 1 may omit the indoor heat exchanger 22 and include a plurality of cold-use heat exchangers 31. In other words, the refrigeration system 1 may be a cold-use system including a plurality of cold-use devices 30 and omit the indoor unit 20. In this case, the multiple cold-use heat exchangers 31 have different evaporation temperature zones. Among the multiple cold-use heat exchangers 31, the cold-use heat exchanger 31 with a higher evaporation temperature zone is connected to the inlet side of the high-stage compressor 12, and the cold-use heat exchanger 31 with a lower evaporation temperature zone is connected to the inlet side of the low-stage compressor 11.

[0074] For example, when the refrigeration system 1 includes a cooling equipment 30 set to a freezing temperature zone and a cooling equipment 30 set to a refrigeration temperature zone, in the cooling equipment 30 set to the refrigeration temperature zone, the cooling heat exchanger 31 is connected to the inlet side of the high-stage compressor 12. In contrast, in the cooling equipment 30 set to the freezing temperature zone, the cooling heat exchanger 31 is connected to the inlet side of the low-stage compressor 11.

[0075] In the above-described embodiment, the refrigeration system 1 includes one indoor heat exchanger 22 and one cold-use heat exchanger 31. However, the present invention is not limited to this, and the refrigeration system 1 may omit the cold-use heat exchanger 31 and include a plurality of indoor heat exchangers 22. In other words, the refrigeration system 1 may be an air-conditioning device that omits the cold-use equipment 30 and includes a plurality of indoor units 20. Furthermore, for example, the refrigeration system 1 may be a hot water heater, a water heater, etc. In other words, the refrigeration system 1 may be any heat pump device including a gas-liquid separator 16 and a throttling mechanism 17 provided on the inlet side of the gas-liquid separator 16.

[0076] In the above-described embodiment, the utilization side heat exchangers connected to the inlet side of the high stage compressor 12 may be provided in parallel in multiple locations on the pipes 78 and 71. Similarly, the utilization side heat exchangers connected to the inlet side of the low stage compressor 11 may be provided in parallel in multiple locations on the pipes 77 and 72.

[0077] Also, for example, a plurality of indoor heat exchangers 22 may be provided in parallel to one another in the piping 78 and the piping 71. In this case, an indoor expansion mechanism 21 may be provided on the inlet side of each of the indoor heat exchangers 22. In this case, the refrigeration system 1 includes a plurality of indoor units 20. Also, in this case, one or more indoor heat exchangers 22 and one or more cold-set heat exchangers 31 may be provided in parallel to one another in the piping 78 and the piping 71.

[0078] A plurality of cooling-use heat exchangers 31 may be provided in parallel to each other in the piping 77 and the piping 72. In this case, a cooling-use inlet-side expansion mechanism 32 may be provided on the inlet side of each of the cooling-use heat exchangers 31. In this case, at least one of the cooling-use heat exchangers 31 provided in parallel to each other in the piping 77 and the piping 72 may have an evaporation temperature zone different from that of the other cooling-use heat exchangers 31.

[0079] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents.

[0080] (Additional Note) The above description of the embodiments discloses the following techniques.

[0081] (Technology 1) A refrigeration system comprising a refrigeration circuit connecting a plurality of compressors, a heat source side heat exchanger, a gas-liquid separator, and a utilization side heat exchanger, wherein the plurality of compressors are composed of a low stage compressor and a high stage compressor, and a throttling mechanism is provided between the gas-liquid separator, the heat source side heat exchanger, and the utilization side heat exchanger, and a first service valve is disposed upstream of the throttling mechanism, and a second service valve is disposed downstream of the throttling mechanism. With this configuration, in the refrigeration device, the first service valve and the second service valve are shared as a connection part for multiple types of external devices with different uses, which makes it possible to suppress an increase in the number of parts related to the connection of the external devices and to simplify the structure of the refrigeration device.

[0082] (Technology 2) The refrigeration apparatus described in Technology 1, wherein the first service valve and the second service valve each have three connection ports including an external connection port to which an external device can be connected, and the refrigeration apparatus is provided with a configuration in which the external connection port is blocked and the remaining two connection ports are connected, a configuration in which all three connection ports are connected, and a configuration in which the external connection port is connected to one of the remaining two connection ports. With this configuration, when a specific external device is connected to the refrigeration circuit of the refrigeration device, the refrigerant can flow between the refrigeration device and the external device. Therefore, the refrigeration device can change the flow path of the refrigerant depending on whether or not there is an external device connected.

[0083] (Technology 3) A refrigeration apparatus according to Technology 2, wherein the first service valve has a configuration that communicates the external connection port with one of the two remaining connection ports that is connected to the throttling mechanism, and the second service valve has a configuration that communicates the external connection port with one of the two remaining connection ports that is connected to the gas-liquid separator. With this configuration, when a specific external device is connected to the refrigeration circuit of the refrigeration device, the refrigerant can flow between the refrigeration device and the external device. Therefore, the refrigeration device can change the flow path of the refrigerant depending on whether or not there is an external device connected.

[0084] (Technology 4) The refrigeration apparatus according to Technology 2 or Technology 3, wherein a humidity control unit can be retrofitted as the external device between the external connection port of the first service valve and the external connection port of the second service valve. With this configuration, the humidity control device can be installed in any location in the room where dehumidification is desired, and therefore, the refrigeration device can suppress condensation in the space to be conditioned or in the location where the cooling equipment is installed.

[0085] (Technology 5) The refrigeration apparatus according to any one of Technology 2 to Technology 4, wherein a refrigerant recovery unit can be retrofitted as the external device to at least one of the external connection port of the first service valve and the external connection port of the second service valve. With this configuration, the refrigeration apparatus can share the first and second service valves as a connection part of the refrigerant recovery unit with other external devices, thereby suppressing an increase in the number of parts related to the connection of the refrigerant recovery unit and simplifying the structure of the refrigeration apparatus.

[0086] (Technology 6) A refrigeration apparatus according to any one of Technology 2 to Technology 5, wherein a fitting capable of connecting a plurality of external devices can be retrofitted to at least one of the external connection port of the first service valve and the external connection port of the second service valve. With this configuration, the refrigeration device can share the first and second service valves as a connection part of the refrigerant recovery unit with multiple other external devices, thereby suppressing an increase in the number of parts related to the connection of the refrigerant recovery unit and simplifying the structure of the refrigeration device.

[0087] (Technology 7) The refrigeration device according to any one of Technology 1 to Technology 6, comprising a plurality of utilization side heat exchangers, the plurality of utilization side heat exchangers being configured with a first utilization side heat exchanger and a second utilization side heat exchanger having a refrigerant evaporation temperature lower than that of the first utilization side heat exchanger. With this configuration, in a refrigeration device equipped with multiple utilization-side heat exchangers, the first service valve and the second service valve are shared as a connection part for multiple types of external devices with different uses, which makes it possible to suppress an increase in the number of parts related to the connection of the external devices in the refrigeration device and to simplify the structure of the refrigeration device. [Industrial Applicability]

[0088] INDUSTRIAL APPLICABILITY The present disclosure can be suitably used as a refrigeration device that uses carbon dioxide (R744), a natural refrigerant with high environmental friendliness, and can improve the efficiency of the air-conditioning temperature range and the efficiency of the entire system. [Explanation of symbols]

[0089] 1 Refrigeration equipment 10 Outdoor unit 11 Low stage compressor 12 High-stage compressor 13 Accumulator 14 Oil separator 15 Outdoor heat exchanger 16 Gas-liquid separator 17 Aperture mechanism 20 Indoor unit 21 Indoor expansion mechanism 22 Indoor heat exchanger 30 Refrigeration equipment 31 Refrigerated heat exchanger 50 First switching mechanism 54 Second switching mechanism 60 Gas refrigerant return pipe 61 Gas refrigerant flow control valve 401 First Service Valve 402 Second Service Valve 405 External equipment 500 External connection port A~D connection part

Claims

1. A plurality of compressors; A heat source side heat exchanger; A gas-liquid separator; A utilization side heat exchanger; A refrigeration circuit is provided to which The plurality of compressors include A low stage compressor; A high-stage compressor; It is composed of The gas-liquid separator; The heat source side heat exchanger and the utilization side heat exchanger, Equipped with a throttle mechanism between A first service valve is disposed upstream of the throttle mechanism, and a second service valve is disposed downstream of the throttle mechanism. Refrigeration equipment.

2. The first service valve and the second service valve are Each of the three connectors includes an external connector for connecting an external device. A form in which the external connection port is blocked and the remaining two connection ports are connected to each other; A form in which all three connection ports are connected to each other; A form in which the external connection port is communicated with one of the remaining two connection ports; Equipped with 2. The refrigeration system of claim 1.

3. the first service valve has a configuration that communicates the external connection port with one of the remaining two connection ports that is connected to the throttle mechanism, The second service valve is configured to communicate the external connection port with one of the remaining two connection ports, the connection port with the gas-liquid separator.

3. The refrigeration system of claim 2.

4. A humidity control unit can be retrofitted as the external device between the external connection port of the first service valve and the external connection port of the second service valve. The refrigeration apparatus according to claim 2 or 3.

5. A refrigerant recovery unit can be retrofitted as the external device to at least one of the external connection port of the first service valve and the external connection port of the second service valve. The refrigeration apparatus according to claim 2 or 3.

6. At least one of the external connection port of the first service valve and the external connection port of the second service valve can be retrofitted with a joint capable of connecting a plurality of external devices. The refrigeration apparatus according to claim 2 or 3.

7. A plurality of user-side heat exchangers are provided, The plurality of utilization side heat exchangers include A first utilization side heat exchanger; a second use-side heat exchanger having a refrigerant evaporation temperature lower than that of the first use-side heat exchanger; Consists of A refrigeration apparatus according to any one of claims 1 to 3.

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