Refrigerating device

Abstract

To provide a refrigerating device that can reduce a load on compressors at the time of filling with a refrigerant.SOLUTION: A refrigerating device according to the present disclosure comprises: a refrigerating circuit connecting a plurality of compressors including a low-stage compressor and a high-stage compressor, a heat source side heat exchanger, a gas-liquid separator, and a plurality of utilization side heat exchangers including a first utilization side heat exchanger, and a second utilization side heat exchanger in which an evaporation temperature of a refrigerant is lower than that in the first utilization side heat exchanger; and a controller. The first utilization side heat exchanger is connected to the high-stage compressor. The second utilization side heat exchanger is connected to the low-stage compressor. A first refrigerant pipe connected to an intermediate pressure pipe between the low-stage compressor and the high-stage compressor comprises a first service valve. The first service valve comprises an outside connection port for receiving the supply of the refrigerant from the outside. The controller can execute a first refrigerant filling mode for filling the refrigerating circuit with the refrigerant supplied from the first service valve by operating the high-stage compressor while stopping the low-stage compressor, as a refrigerant filling mode.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method of replacing a refrigerant through a service valve provided in a low-pressure pipe. [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 device that can prevent a compressor from running idle when charging a refrigerant. [Means for solving the problem]

[0005] a first service valve in a first refrigerant pipe connected to a medium-pressure pipe between the low-stage compressor and the high-stage compressor, the first service valve having an external connection port for receiving a supply of refrigerant from the outside; and the controller is capable of executing a first refrigerant charging mode in which the high-stage compressor is operated with the low-stage compressor stopped, thereby charging the refrigeration circuit with refrigerant supplied from the first service valve. [Effects of the Invention]

[0006] The refrigeration apparatus according to the present disclosure stops the low-stage compressor when charging refrigerant through the first service valve, making it easy to maintain an appropriate pressure difference, thereby preventing the compressor from running idle during refrigerant charging. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a circuit diagram of a refrigeration device showing operation during cooling operation in embodiment 1. [Figure 2] Refrigeration unit block diagram [Figure 3] Flowchart showing the setting operation of refrigerant charging by the refrigeration device [Figure 4] 1 is a flowchart showing the operation of a refrigeration device in an initial refrigerant charging mode and a first refrigerant charging mode. [Figure 5] FIG. 1 is a diagram showing a refrigeration circuit of a refrigeration device in an initial refrigerant charging mode. [Figure 6] FIG. 1 is a diagram showing a refrigeration circuit of a refrigeration device in a first refrigerant charging mode. [Figure 7] 10 is a flowchart showing the operation of the refrigeration device in a second refrigerant charging mode. [Figure 8] FIG. 10 is a diagram showing the refrigeration circuit of the refrigeration device in a second refrigerant charging mode. [Figure 9] Circuit diagram of refrigeration device 1 showing heating operation [Figure 10] Circuit diagram of a refrigeration system showing heating operation when the heat output from the cooling equipment is insufficient [Figure 11] Circuit diagram of a refrigeration system showing operation when heating heat is not required [Figure 12] FIG. 10 is a diagram showing a refrigeration circuit of a refrigeration device according to a second embodiment. [Figure 13] FIG. 1 is a diagram showing a refrigeration circuit in an initial refrigerant charging mode of a refrigeration device. [Figure 14] FIG. 1 is a diagram showing a refrigeration circuit of a refrigeration device in a first refrigerant charging mode. [Figure 15]FIG. 10 is a diagram showing the refrigeration circuit of the refrigeration device in a second refrigerant charging mode. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Findings that formed the basis of this disclosure) At the time when the inventors came up with the idea of the present disclosure, refrigeration systems had service valves on high-pressure and low-pressure pipes that service technicians use when charging refrigerant. However, in a refrigeration system with a two-stage compression configuration, when an attempt is made to charge refrigerant through a service valve provided in the low-pressure piping, both the high-stage compressor and the low-stage compressor must be operated. Therefore, if the amount of refrigerant charged is large, the pressure in the medium-pressure piping rises to the same level as the high-pressure pressure, and conversely, if the amount of refrigerant charged is small, the pressure drops to the same level as the low-pressure pressure, resulting in an issue in which the compressor runs idly and is subjected to a load. The inventors discovered this issue, and in order to solve this issue, they came up with the subject matter of the present disclosure. Therefore, the present disclosure provides a refrigeration device that can prevent the compressor from running idle when charging a refrigerant.

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. 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.

[0010] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS. [1-1.Configuration] [1-1-1. Configuration of refrigeration equipment] FIG. 1 is a diagram showing the refrigeration circuit of the refrigeration device 1 in the first embodiment. For ease of explanation, in FIG. 1, the valve body in the open state is shown in white, the valve body in the closed state is shown in black, and the throttle mechanism in the closed state is shown with a dot. For ease of explanation, in FIG. 1, pipes through which the refrigerant flows are shown with thick lines, and pipes through which the refrigerant does not flow are shown with thin lines. This also applies to the subsequent figures. 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 for the interior of a store such as a convenience store or supermarket, and the refrigeration equipment 30 provides cooling for the interior of refrigerated showcases and freezer showcases that serve as cooling storage facilities installed within the store.

[0011] 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 on the discharge side of the low-stage compressor 11. An accumulator 13 is arranged 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. An intermediate-pressure pipe 80 is arranged between the discharge port of the low-stage compressor 11 and the suction port of the high-stage compressor 12. The intermediate-pressure pipe 80 connects the discharge port of the low-stage compressor 11 with the accumulator 13.

[0012] An oil separator 14 is connected to the discharge 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. A first heating pipe 41 is connected to the inlet side of the first cooling valve 51 of the pipe 40. The first heating pipe 41 is equipped with a first heating valve 52 (second on-off valve). The first heating pipe 41 is connected to a pipe 71 that connects the outlet side of the indoor heat exchanger 22 of the indoor unit 20 to the medium-pressure pipe 80. An on-off valve 23 is provided on the pipe 71.

[0013] A first outdoor return pipe 42 is connected to the outlet side of the first cooling valve 51 of the pipe 40. The first outdoor return pipe 42 is equipped with an outdoor refrigerant return valve (third on-off valve) 53. The first outdoor return pipe 42 is connected to a pipe 72 that connects the cooling-use heat exchanger 31 of the cooling equipment 30 to the suction port of the low-stage compressor 11, and this pipe 72 is connected to the cooling-use outlet-side pressure adjustment mechanism 33 of the cooling equipment 30. In this embodiment, the pipe 72 is an example of a "low-pressure pipe."

[0014] A second switching mechanism 54 is connected to the outdoor heat exchanger 15, and the 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 connecting parts A, B, C, and D in a ring shape. A second cooling valve (first control valve) 55 and a check valve 59 are arranged in the first pipe 73, a refrigerant return expansion mechanism (second control valve) 58 that controls the flow rate is arranged in the second pipe 74, and a third cooling valve (third control valve) 56 and a check valve 59 are arranged in the third pipe 75. Furthermore, a second heating valve (fourth control valve) 57 and a check valve 59 are arranged in the fourth pipe 76.

[0015] A connection 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 B between the refrigerant return expansion mechanism 58 and the third cooling valve 56 is connected to a pipe 77 that connects the liquid outlet side of the gas-liquid separator 16 and the cooling-unit heat exchanger 31. The cooling-unit inlet-side expansion mechanism 32 is connected to this pipe 77. A connection 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 pipe 78 is connected to the indoor expansion mechanism 21 of the indoor unit 20.

[0016] The indoor heat exchanger 22 and the cold-use heat exchanger 31 function as a so-called utilization-side heat exchanger. As described above, the indoor heat exchanger 22 is a use-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 thereof 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 in accordance with the indoor temperature set in the indoor unit 20. The evaporation temperature range of the indoor heat exchanger 22 is, for example, 3°C to 6°C.

[0017] As described above, the refrigeration heat exchanger 31 is a user-side heat exchanger provided in the refrigeration equipment 30. The refrigeration heat exchanger 31 functions as an evaporator, and the evaporation temperature thereof is determined by the opening degree of the indoor expansion mechanism 21. In the present embodiment, the evaporation temperature of the refrigeration heat exchanger 31 is determined according to the internal temperature set in the refrigeration equipment 30.

[0018] The refrigeration equipment 30 of this embodiment can select and set the temperature zone inside the cabinet from among, for example, a refrigeration temperature zone (3°C to 6°C), a temperature zone slightly higher than the refrigeration temperature zone (3°C to 8°C), a partial temperature zone (-3°C to -1°C), and a freezing temperature zone (-20°C to -18°C). Therefore, the evaporation temperature zone of the refrigeration heat exchanger 31 is set lower than the temperature zone inside the cabinet.

[0019] When the refrigeration equipment 30 is set to the refrigeration temperature range, the evaporation temperature range of the refrigeration heat exchanger 31 is, for example, from -5°C to 0°C. When the cooling equipment 30 is set to the partial temperature zone, the evaporation temperature zone of the cooling heat exchanger 31 is, for example, from -12°C to -8°C. When the refrigeration equipment 30 is set to the freezing temperature range, the evaporation temperature range of the refrigeration heat exchanger 31 is, for example, from -40°C to -20°C.

[0020] In this way, two use-side heat exchangers with different evaporation temperature ranges are provided in the refrigeration device 1. Of these two use-side heat exchangers 22 and 31 with different evaporation temperature ranges, the indoor heat exchanger 22 is connected to the suction side of the high-stage compressor 12, and the cold-use heat exchanger 31, which has a lower evaporation temperature range than the indoor heat exchanger 22, is connected to the suction side of the low-stage compressor 11. The indoor heat exchanger 22 corresponds to the "first use-side heat exchanger" in the present disclosure, and the cold-use heat exchanger 31 corresponds to the "second use-side heat exchanger" in the present disclosure.

[0021] A connection 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. A throttle mechanism 17 is arranged in the pipe 79.

[0022] A gas refrigerant return pipe 60 is connected to the gas outlet side of the gas-liquid separator 16, and the gas refrigerant return pipe 60 is connected to an intermediate pressure pipe 80 and communicates with the accumulator 13 via the intermediate pressure pipe 80. A portion of the gas refrigerant separated in the gas-liquid separator 16 flows into the gas refrigerant return pipe 60. A gas refrigerant flow rate control valve 61 is connected to the gas refrigerant return pipe 60. The gas refrigerant flow rate control valve 61 is a valve whose opening degree can be adjusted, and opens and closes the gas refrigerant return pipe 60. The gas refrigerant flow rate control valve 61 blocks the flow of refrigerant in the gas refrigerant return pipe 60 by being in a fully closed state. In the present embodiment, the gas refrigerant return pipe 60 is an example of a "first refrigerant pipe". In the present embodiment, the gas refrigerant flow rate control valve 61 is an example of a "first opening and closing unit". 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 present embodiment, the first service valve 401 is disposed between the gas refrigerant flow rate control valve 61 and the accumulator 13. The gas refrigerant flow rate control valve 61 is located on the gas-liquid separator 16 side of the gas refrigerant return pipe 60 with the first service valve 401 as the reference. In other words, the gas refrigerant flow rate control valve 61 is located on the opposite side of the gas refrigerant return pipe 60 to the medium-pressure pipe 80 with the first service valve 401 as the reference. Further, in the piping 72, a second service valve 402 is arranged between the low-stage compressor 11 and the outlet-side pressure adjustment mechanism for cooling 33.

[0024] The first service valve 401 has an external connection port 500A to which a refrigerant cylinder can be connected. The first service valve 401 has a first connection port 501A that connects to the gas refrigerant return pipe 60 on the medium-pressure pipe 80 side with respect to the external connection port 500A. The first service valve 401 has a second connection port 502A that connects to the gas refrigerant return pipe 60 on the gas-liquid separator 16 side with respect to the external connection port 500A, i.e., on the side opposite to the medium-pressure pipe 80. In the present embodiment, the first connection port 501A is an example of a "second opening / closing part." The second service valve 402 has an external connection port 500B to which a refrigerant cylinder can be connected. The second service valve 402 has a first connection port 501B that connects to the pipe 72 on the low-stage compressor 11 side with respect to the external connection port 500B. The second service valve 402 has a second connection port 502B that connects to the refrigerated heat exchanger 31 side with respect to the external connection port 500B.

[0025] The first service valve 401 can be switched to a fully open mode in which all connection ports 500A, 501A, and 502A are open. The first service valve 401 can be switched to an operating mode in which only the external connection port 500A is closed and the connection ports 501A and 502A are open. The first service valve 401 can be switched to a filling mode in which only the first connection port 501A is closed and the connection ports 500A and 502A are open. The second service valve 402 can be switched to a fully open mode in which all of the connection ports 500B, 501B, and 502B are open. The second service valve 402 can be switched to an operating mode in which only the external connection port 500B is closed and the connection ports 501B and 502B are open. The second service valve 402 can be switched to a filling mode in which only the first connection port 501B is closed and the connection ports 500B and 502B are open. These configurations improve the ease of service, such as replacing the compressor.

[0026] In this embodiment, each service valve 401, 402 can be electronically controlled. The mode of each service valve 401, 402 is switched among a fully open mode, an operating mode, and a filling mode according to a control signal sent from the controller 700.

[0027] A low-pressure side pressure sensor 601 is arranged in the pipe 72 between the cooling outlet side pressure adjustment mechanism 33 and the second service valve 402 to measure the low-pressure pressure. An intermediate-pressure side pressure sensor 602 is arranged in the gas refrigerant return pipe 60 between the intermediate-pressure pipe 80 and the first service valve 401 to measure the intermediate pressure. A high-pressure side pressure sensor 603 is arranged between the high-stage compressor 12 and the oil separator 14 to measure the high-pressure pressure. A second intermediate-pressure side pressure sensor 604 is arranged in the gas refrigerant return pipe 60 to measure the intermediate pressure between the gas-liquid separator 16 and the gas refrigerant flow rate control valve 61.

[0028] The refrigeration system 1 has a controller 700 that stores and executes modes for controlling the refrigeration circuit, and has modes that pattern the valve opening and compressor control during refrigerant charging. The modes include, for example, an initial refrigerant charging mode, a first refrigerant amount adjustment mode, and a second refrigerant amount adjustment mode. The controller 700 determines whether to switch between these modes and has a display means that notifies the user of the determination result. The determination method is, for example, based on the rate of change in pressure. The display means may, for example, be equipped with an indicator lamp that flashes, an alarm that notifies the user with a sound, a display panel such as a monitor that displays text and images on the screen, or a combination of these.

[0029] The frequency in the compressor control by the controller 700 can be fixed to a frequency specified by the user, or fixed to a frequency automatically determined by the controller 700. The method of automatically determining the frequency estimates the cooling load calculated from the outdoor temperature and the set temperatures of the indoor unit 20 and cooling equipment 30 specified by the user, and determines the target amount of refrigerant to be charged and the frequency at which the compressor will operate based on data relating to the cooling load, refrigerant amount, and frequency obtained in advance.

[0030] FIG. 2 is a block diagram of the refrigeration device 1. The controller 700 includes a control unit 701 and a storage unit 703. In this embodiment, the control unit 701 includes a processor such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). In this embodiment, the storage unit 703 includes, for example, a magnetic storage device, a semiconductor storage element, or other types of non-volatile storage device. The storage unit 703 may include a RAM (Random Access Memory) that forms a work area for the control unit 701.

[0031] The storage unit 703 stores mode information 705. The mode information 705 includes information on the valve opening degree of each valve and information on the operating state of each compressor 11, 12 when each refrigerant charging mode executed by the controller 700 is executed. Each refrigerant charging mode is executed by the controller 700 when refrigerant is charged into the refrigeration circuit of the refrigeration device 1. The controller 700 can execute an initial refrigerant charging mode, a first refrigerant charging mode, and a second refrigerant charging mode as the refrigerant charging mode.

[0032] The storage unit 703 stores switching information 707. The switching information 707 includes information used to determine whether to switch or terminate each refrigerant charging mode.

[0033] The storage unit 703 stores setting information 709. The setting information 709 includes a set temperature of the refrigeration equipment 30 having the refrigeration heat exchanger 31. The setting information 709 includes information for calculating the operation frequency of the compressors 11, 12 in each refrigerant charging mode. The setting information 709 includes information for calculating a target refrigerant amount, which is a target amount of refrigerant to be charged into the refrigeration circuit of the refrigeration device 1. The setting information 709 includes information for calculating a target high-pressure pressure used when determining that refrigerant charging is complete, from the relationship between the operation frequency and the target refrigerant amount.

[0034] The controller 700 is connected to each device of the outdoor unit 10. The controller 700 is also connected to the indoor unit 20 and the cooling equipment 30 via the outdoor unit I / F 95. The outdoor unit I / F 95 has communication hardware such as a communication interface circuit and a connector for communicating with each device via a cable or the like in accordance with a predetermined communication protocol. The outdoor unit I / F 95 sends data received from each device to the controller 700, and also sends data received from the controller 700 to each device.

[0035] The refrigeration device 1 has a notification unit 801. The notification unit 801 is connected to the controller 700 via the outdoor unit I / F 95. The notification unit 801 notifies the user when each refrigerant charging mode is switched or terminated. In this embodiment, the notification unit 801 includes a display device configured with a liquid crystal display panel, an organic EL (Electro Luminescence) panel, a 7-segment LED (Light Emitting Diode), or the like.

[0036] The refrigeration apparatus 1 has an input unit 803. The input unit 803 is connected to the controller 700 via the outdoor unit I / F 95. The input unit 803 is equipped with a switch, a touch panel, or the like that accepts input operations. In this embodiment, the input unit 803 includes a display device that is configured with a liquid crystal display panel, an organic EL panel, a 7-segment LED, or the like, for confirming the accepted input operations.

[0037] [1-2. Operation] The operation of the refrigeration device 1 of this embodiment will be described below. [1-2-1. Refrigerant charging setting operation] Fig. 3 is a flowchart showing the operation of the refrigerant charging setting operation of the refrigeration device 1. The operation of Fig. 3 is started, for example, when a switch or the like provided on the input unit 803 or the like of the refrigeration device 1 is operated as a trigger.

[0038] In step SA1, the controller 700 estimates the cooling load. The control unit 701 reads the setting information 709 stored in the memory unit 703 and acquires the set temperature of the cooling equipment 30. The control unit 701 also acquires the outside air temperature from an outside air thermometer provided in the refrigeration device 1 or through information communication with the outside. The acquired outside air temperature is a value that is considered to be the outside air temperature at the installation location of the refrigeration device 1 at the time of step SA1. The control unit 701 estimates the cooling load using the acquired set temperature of the refrigeration equipment 30 and the outside air temperature.

[0039] In step SA2, controller 700 calculates the target refrigerant amount. Control unit 701 reads setting information 709 stored in memory unit 703 and acquires data correlating the cooling load with the target refrigerant amount. Control unit 701 calculates the target refrigerant amount using the read data and the cooling load estimated in step SA1.

[0040] In step SA3, controller 700 calculates the target high pressure. Control unit 701 reads setting information 709 stored in memory unit 703 and acquires data correlating the target refrigerant amount with the target high pressure. Control unit 701 calculates the target high pressure using the read data and the target refrigerant amount calculated in step SA2.

[0041] In step SA4, the controller 700 determines whether the frequency setting of each compressor 11, 12 in each refrigerant charging mode is set to the automatic mode. The frequency setting of each compressor 11, 12 in each refrigerant charging mode can be switched between the automatic mode and the manual mode. Switching between the automatic mode and the manual mode is performed, for example, by an input operation via the input unit 803, and a variable corresponding to the switched mode is stored in the storage unit 703. The control unit 701 may determine whether the frequency setting of each compressor 11, 12 in each refrigerant charging mode is the manual mode or the automatic mode, for example, by reading the variable from the storage unit 703. If it is determined that the frequency setting of each compressor 11, 12 in each refrigerant charging mode is the automatic mode (step SA4: YES), the process proceeds to step SA5. If it is determined that the frequency setting is the manual mode (step SA4: NO), the process proceeds to step SA7.

[0042] In step SA5, the controller 700 calculates the operating frequency of each compressor 11, 12 when each refrigerant charging mode is being executed. The control unit 701 reads out setting information 709 stored in the memory unit 703 and acquires data correlating the outside air temperature and cooling load with the operating frequency of each compressor 11, 12. The controller 700 calculates the operating frequency of each compressor 11, 12 when each refrigerant charging mode is being executed, based on the outside air temperature and cooling load acquired in step SA1.

[0043] In step SA6, the frequency calculated in step SA5 is set as the operating frequency of each compressor 11, 12 during refrigerant charging. In step SA7, the frequency specified by an input operation to input unit 803 is set as the operating frequency of each compressor 11, 12 during refrigerant charging. When step SA6 or step SA7 is completed, the process of FIG. 3 ends.

[0044] [1-2-2. Operation during refrigerant charging] Next, the operation of the refrigeration device 1 during refrigerant charging in this embodiment will be described. The following operation enables charging of an appropriate amount of refrigerant in a refrigeration circuit with a two-stage compression configuration, and further allows refrigerant charging to continue even when the amount of gas remaining in the refrigerant cylinder is small.

[0045] First, evacuation before charging the refrigerant is performed by connecting the vacuum pump and first service valve 401 with a charge hose via a gauge manifold. When evacuation is performed, all valves provided in the refrigeration device 1 are opened. However, the second service valve 402 is in the operating mode, and the external connection port 500B is closed. Once evacuation is complete, refrigerant charging begins.

[0046] After evacuation, the external connection port 500A of the first service valve 401 is connected to a refrigerant cylinder filled with the refrigerant to be charged into the circuit with a charge hose via a manifold gauge. When connecting the charge hose, air is purged to prevent air from entering the circuit.

[0047] FIG. 4 is a flowchart showing the operation of the refrigeration device 1, and shows the operation of the refrigeration device 1 in the initial refrigerant charging mode and the first refrigerant charging mode. FIG. 5 is a diagram showing the refrigeration circuit of the refrigeration device 1 in the initial refrigerant charging mode. FIG. 6 is a diagram showing the refrigeration circuit of the refrigeration device 1 in the first refrigerant charging mode. The operation of FIG. 4 is started, for example, when a switch or the like provided on the refrigeration device 1 is operated as a trigger. The operation of the valves in FIG. 4 is included as the initial refrigerant charging mode and the first refrigerant charging mode in mode information 705 stored in memory unit 703, and is automatically performed by controller 700.

[0048] In step SB1, the controller 700 executes an operation to switch to the initial refrigerant charging mode. The controller 700 controls the open / close states of the valves provided in the refrigerant circuit of the refrigeration device 1, and divides the refrigerant flow path in the refrigeration circuit into two. Specifically, the controller 700 fully closes the third cooling valve 56, the refrigerant return expansion mechanism 58, the throttling mechanism 17, and the cooling inlet expansion mechanism 32. The first service valve 401 is set to the charging mode. The second service valve 402 is set to the operating mode. In addition, the gas refrigerant flow control valve 61 is set to the open state, and its opening degree is set to the maximum.

[0049] In the initial refrigerant charging mode after completion of step SB1, as shown in Fig. 4, the refrigeration circuit of the refrigeration device 1 is divided into two parts, a part including the gas-liquid separator 16 and a part including the low-stage compressor 11 and the high-stage compressor 12, by the closed valves 56, 58, 17, 32 and first service valve 401. In the initial refrigerant charging mode, the external connection port 500A of the first service valve 401 communicates with the side of the two divided flow paths that includes the gas-liquid separator 16. Therefore, in the initial refrigerant charging mode, refrigerant is charged into the side of the two divided flow paths of the refrigeration circuit that includes the gas-liquid separator 16.

[0050] In step SB2, the controller 700 determines whether to switch the mode from the initial refrigerant charging mode to the first refrigerant amount adjustment mode. Specifically, the controller 700 determines whether the rate of change per hour of the pressure P4 measured by the second intermediate pressure side pressure sensor 604 has fallen below a first rate of change. The first rate of change is included in the switching information 707 stored in the memory unit 703. The first rate of change is an example of the "predetermined rate of change" in the present disclosure.

[0051] After step SB1, as the amount of refrigerant charged into the refrigeration circuit increases, the pressure P4 in the refrigeration circuit increases and the internal pressure of the refrigerant cylinder decreases. Therefore, as the amount of refrigerant charged into the refrigeration circuit increases, the refrigerant charging speed decreases and the rate of change of pressure P4 per unit time decreases. That is, in step SB2, it is determined whether the internal pressure of the refrigerant cylinder and the pressure on the refrigeration circuit side have reached equilibrium and further refrigerant charging is no longer possible, based on the rate of change of pressure P4 per unit time.

[0052] In step SB2, if the rate of change per unit time of the pressure P4 is equal to or greater than the first rate of change (step SB2: NO), the determination in step SB2 is repeated. If the rate of change per unit time of the pressure P4 falls below the first rate of change, the process proceeds to step SB3. When the process proceeds from step SB2 to step SB3, the refrigerant charging initial mode ends.

[0053] In step SB3, the controller 700 controls the open / close states of the valves to connect the two separated refrigeration circuit flow paths. Specifically, the controller 700 opens the indoor expansion mechanism 21, the on-off valve 23, the cooling inlet expansion mechanism 32, the first cooling valve 51, the second cooling valve 55, and the third cooling valve 56. The controller 700 also closes the first heating valve 52, the outdoor refrigerant return valve 53, the second heating valve 57, the refrigerant return expansion mechanism 58, and the gas refrigerant flow control valve 61. The controller 700 sets the second service valve 402 to the operating mode. The controller 700 sets the first service valve 401 to the fully open mode. As shown in FIG. 6, the open / close states of these valves are the same as those during cooling operation, except that the gas refrigerant flow control valve 61 is fully closed and the first service valve 401 is fully open. Information about the opening degree of each valve in step SB3 is included in the mode information 705 as a first refrigerant charging mode, and is performed automatically by the controller 700. By opening and closing this gas refrigerant flow control valve 61, it is possible to provide a method that is different from the refrigerant charging initial mode, even when refrigerant is charged from the same first service valve 401.

[0054] In step SB4, the controller 700 starts the operation of the two high-stage compressors 12. At this time, in the automatic mode, the operation frequency of the high-stage compressors 12 is fixed to the frequency calculated in step SA5 of Fig. 3. In the manual mode, the operation frequency of the high-stage compressors 12 is fixed to the frequency specified by the input operation received by the input unit 803.

[0055] The operations of steps SB3 and SB4 switch the operation of the refrigeration apparatus 1 to a first refrigerant charging mode. In the first refrigerant charging mode, refrigerant is charged by using single-stage compression in which only the high-stage compressor 12 is operated, lowering the intermediate pressure in the refrigerant piping to which the first service valve 401 is connected, and creating a pressure difference between the pressure in the refrigerant cylinder and the intermediate pressure.

[0056] 6, in the first refrigerant charging mode, the refrigerant charged from the external connection port 500A of the first service valve 401 flows through the gas refrigerant return pipe 60 to the medium-pressure pipe 80, the accumulator 13, and the high-stage compressor 12. As described above, in the gas refrigerant return pipe 60, the gas refrigerant flow control valve 61 located closer to the gas-liquid separator 16 than the first service valve 401 is closed. For this reason, the pressure in the gas refrigerant return pipe 60 can be reduced by operating the high-stage compressor 12.

[0057] In step SB5, controller 700 determines whether to switch the mode from the first refrigerant amount adjustment mode to the second refrigerant amount adjustment mode. Specifically, controller 700 determines whether the rate of change per hour of high-pressure pressure P3 measured by high-pressure-side pressure sensor 603 has fallen below a second rate of change. The second rate of change is included in switching information 707 stored in memory 703. In step SB5, similar to step SB2, it is determined based on the rate of change per hour of high-pressure pressure P3 whether the internal pressure of the refrigerant cylinder and the pressure on the refrigeration circuit side have reached equilibrium and further refrigerant charging is no longer possible. The second rate of change is an example of a "predetermined rate of change" in the present disclosure.

[0058] In step SB5, if the rate of change per unit time of the high-pressure P3 is equal to or greater than the second rate of change (step SB5: NO), the determination in step SB5 is repeated. If the rate of change per unit time of the high-pressure P3 is lower than the second rate of change (step SB5: YES), the process proceeds to step SB6.

[0059] In step SB6, the controller 700 ends the first refrigerant charging mode. Specifically, the controller 700 stops the high-stage compressor 12. The controller 700 switches the first service valve 401 to the operating mode and closes the external connection port 500A. This closes the refrigeration circuit of the refrigeration device 1 to the outside.

[0060] In step SB7, controller 700 causes notification unit 801 to issue a notification. The notification by notification unit 801 in step SB7 includes an instruction to reconnect the charge hose connected to first service valve 401 to connection port 500B of second service valve 402. By executing step SB7, a series of operations from the start of the initial refrigerant charging mode to the end of the first refrigerant charging mode is completed.

[0061] After the series of operations shown in FIG. 4 is completed, the charge hose of the refrigerant cylinder is reconnected from the first service valve 401 to the second service valve 402 by a service technician following the instructions shown in the notice.

[0062] Fig. 7 is a flowchart showing the operation of the refrigeration device 1 in the second refrigerant charging mode. Fig. 8 is a diagram showing the refrigeration circuit of the refrigeration device 1 in the second refrigerant charging mode. The operation of Fig. 7 is triggered by the operation of a predetermined switch or the like after step SB7.

[0063] In step SC1, the controller 700 opens and closes each valve of the refrigeration apparatus 1. The controller 700 switches the second service valve 402 to a fully open state. Furthermore, the controller 700 sets each valve of the refrigeration apparatus 1, except for the second service valve 402, to the same open / close states as during cooling operation. Specifically, the controller 700 opens the indoor expansion mechanism 21, the on-off valve 23, the cooling inlet expansion mechanism 32, the first cooling valve 51, the second cooling valve 55, the third cooling valve 56, and the gas refrigerant flow control valve 61. More specifically, the controller 700 fully opens the gas refrigerant flow control valve 61. Furthermore, the controller 700 closes the first heating valve 52, the outdoor refrigerant return valve 53, the second heating valve 57, and the refrigerant return expansion mechanism 58. The controller 700 sets the first service valve 401 to an operating mode. The operation of each valve in step SC1 is included as a second refrigerant charging mode in mode information 705 stored in storage unit 703, and is automatically executed by controller 700.

[0064] In step SC2, the controller 700 starts the operation of the low-stage compressor 11 and the high-stage compressor 12. At this time, in the automatic mode, the operation frequencies of the compressors 11 and 12 are fixed to the frequencies calculated in step SA5 of Fig. 3. In the manual mode, the operation frequencies of the compressors 11 and 12 are fixed to the frequencies specified by the input operation received by the input unit 803.

[0065] By executing steps SC1 and SC2, the operation of the refrigeration device 1 switches to the second refrigerant charging mode. In the second refrigerant charging mode, the refrigeration device 1 performs two-stage compression and charges the refrigerant by lowering the low-pressure in the refrigerant pipe connected to the second service valve 402 to create a pressure difference between the pressure in the refrigerant cylinder and the intermediate pressure. This makes it possible to charge the refrigerant even when the amount of gas remaining in the refrigerant cylinder is low.

[0066] In step SC3, controller 700 determines whether the target refrigerant amount has been filled into the circuit. For this determination, for example, the value of high-pressure pressure P3 measured by high-pressure-side pressure sensor 603 relative to the target high-pressure pressure for the target refrigerant amount and operation frequency is used. That is, if high-pressure pressure P3 is equal to or greater than the target high-pressure pressure, it is determined that the target refrigerant amount has been filled into the circuit.

[0067] If it is determined that the target amount of refrigerant has been charged into the circuit (step SC3: YES), the process proceeds to step SC4. If it is determined that the target amount of refrigerant has not been charged into the circuit (step SC3: NO), step SC3 is repeated.

[0068] In step SC4, the controller 700 ends the second refrigerant charging mode. The controller 700 stops the high-stage compressor 12 and the low-stage compressor 11. The controller 700 switches the second service valve 402 to the operating mode and closes the external connection port 500B. This closes the refrigerant circuit of the refrigeration device 1 to the outside.

[0069] In step SC5, the controller 700 causes the notification unit 801 to issue a notification. The notification by the notification unit 801 in step SC5 includes information that the execution of the second refrigerant charging mode has ended. By executing step SC5, the series of operations of the refrigeration device 1 during refrigerant charging is completed.

[0070] [1-2-3. Operation during operation] Next, the operation during operation of this embodiment will be described. During the following operation during operation, the service valves 401 and 402 are in the operating state, and the external connection ports 500A and 500B are closed. 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 cooling heat exchanger 31 are used as evaporators. When performing cooling operation, first switching mechanism 50 opens first cooling valve 51 and closes first heating valve 52 and outdoor refrigerant return valve 53. Second switching mechanism 54 opens second cooling valve 55 and third cooling valve 56 and closes second heating valve 57 and 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, where it is further compressed and discharged toward the oil separator 14.

[0071] 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, where it exchanges heat with outside air. The refrigerant after heat exchange is sent from connection A of second switching mechanism 54 via second cooling valve 55 to gas-liquid separator 16. The refrigerant separated in gas-liquid separator 16 passes through piping 77 to reach connection B of second switching mechanism 54. One of the refrigerants branched at connection B is sent to indoor heat exchanger 22 via third cooling valve 56 and indoor expansion mechanism 21 of 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, the on-off valve 23, the intermediate-pressure pipe 80, and the accumulator 13, and is returned to the suction side of each high-stage compressor 12.

[0072] The other refrigerant branched at connection point B is sent to refrigeration heat exchanger 31 via refrigeration inlet side expansion mechanism 32 of refrigeration equipment 30, where it undergoes heat exchange and cools refrigeration equipment 30. The refrigerant that has undergone heat exchange in refrigeration heat exchanger 31 is returned to low-stage compressor 11 via refrigeration outlet side pressure adjustment mechanism 33.

[0073] Next, the operation when the first heating operation (heating operation) is performed will be described. 9 is a circuit diagram of the refrigeration device 1 showing the heating operation, in which the flow of the refrigerant is indicated by arrows in the figure. In the first heating operation, the indoor heat exchanger 22 is used as a gas cooler or a radiator, and the cooling heat exchanger 31 is used as an evaporator. 9, when performing heating operation, first switching mechanism 50 opens first heating valve 52 and closes first cooling valve 51 and outdoor refrigerant return valve 53. Further, second switching mechanism 54 opens second heating valve 57 and closes second cooling valve 55, third cooling valve 56, and refrigerant return expansion mechanism 58.

[0074] 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, where it is further compressed 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.

[0075] The refrigerant that has exchanged heat in indoor heat exchanger 22 passes through indoor expansion mechanism 21, reaches connection part C of second switching mechanism 54, and is sent to gas-liquid separator 16 via second heating valve 57. The refrigerant separated in gas-liquid separator 16 passes through piping 77, reaches connection part B of second switching mechanism 54, and is sent to chilling-set heat exchanger 31 via chilling-set inlet-side expansion mechanism 32. This refrigerant exchanges heat in chilling-set heat exchanger 31, and cools chilling-set equipment 30. The refrigerant that has exchanged heat in the chiller heat exchanger 31 passes through the pipe 72 and is returned to the suction side of the low-stage compressor 11 via the chiller outlet side pressure adjustment mechanism 33 . In the refrigeration device 1 of the present disclosure, during the first heating operation, the indoor heat exchanger 22 functions as a gas cooler or a radiator, and the outdoor heat exchanger 15 is not used.

[0076] Next, we will explain the operation of performing the second heating operation at full capacity when the amount of heat exhausted to the cooling equipment 30 is insufficient, for example, when the outside air temperature is lower than the temperature inside the cooling equipment 30. Fig. 10 is a circuit diagram of the refrigeration device 1 showing the operation of the heating operation when the amount of heat exhausted to the cooling equipment 30 is insufficient. The flow of the refrigerant is indicated by arrows in the figure. In the second heating operation, the indoor heat exchanger 22 is used as a gas cooler or a radiator, and the cooling heat exchanger 31 and the outdoor heat exchanger 15 are used as evaporators. When performing the second heating operation 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.

[0077] 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, where it is further compressed 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, where it exchanges heat with the indoor air, heating the indoor air.

[0078] The refrigerant that has exchanged heat in indoor heat exchanger 22 is sent to gas-liquid separator 16 via second heating valve 57 of second switching mechanism 54. The refrigerant separated in gas-liquid separator 16 reaches connection B of second switching mechanism 54 through piping 77. One of the refrigerants branched at connection B passes through refrigerant return expansion mechanism 58 of second switching mechanism 54 and connection A, and is sent to outdoor heat exchanger 15, where it exchanges heat with outside air. The other refrigerant branched at connection B is sent to chilled-unit heat exchanger 31 via chilled-unit inlet-side expansion mechanism 32, where it exchanges heat and cools chilled-unit equipment 30. The refrigerant that has exchanged heat in chilled-unit heat exchanger 31 and the refrigerant that has exchanged heat in outdoor heat exchanger 15 and is sent from first outdoor return piping 42 are joined at piping 72 and returned to the suction side of low-stage compressor 11.

[0079] 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.

[0080] This allows the exhaust heat from the refrigeration 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, thereby increasing the heating capacity when the amount of heat exhausted to the refrigeration equipment 30 is insufficient.

[0081] In this case, if the outside air temperature becomes lower than the temperature inside the refrigerator 30, the evaporation temperature of the refrigerator 30 must be lowered in order to draw heat from the outdoor heat exchanger 15. Lowering the evaporation temperature of the refrigerator 30 will result in a temperature lower than the specified temperature, shortening the thermocycle, resulting in short-cycle operation, and even leading to the risk of frozen products. In this embodiment, the opening degree of the outlet pressure adjustment mechanism 33 for cooling is controlled to balance the pressure with the refrigerant sent from the outdoor heat exchanger 15, thereby avoiding the above-mentioned inconvenience.

[0082] Next, an operation when a large capacity is required but a heating heat amount is not required in the cooling equipment 30 will be described. Fig. 11 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. 11, the third heating operation is performed by using the outdoor heat exchanger 15 and the indoor heat exchanger 22 as gas coolers or radiators, and the cooling heat exchanger 31 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.

[0083] 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, where it is further compressed and discharged toward the oil separator 14.

[0084] 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, is 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, exchanging heat with outdoor air in the outdoor heat exchanger 15 and 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 passes from connection A of the second switching mechanism 54 to the second cooling valve 55, and the refrigerant that has exchanged heat in the indoor heat exchanger 22 passes from connection C of the second switching mechanism 54 to the second heating valve 57, where they join and are sent to the gas-liquid separator 16. The refrigerant separated in the gas-liquid separator 16 is sent through a pipe 77 to the chiller heat exchanger 31, where it undergoes heat exchange and cools the chiller equipment 30. The refrigerant that has exchanged heat in the chiller heat exchanger 31 is returned to the suction side of the low-stage compressor 11 via the chiller outlet side pressure adjustment mechanism 33.

[0085] According to this, during heating operation, the exhaust heat from the cooling equipment 30 can be dissipated by the outdoor heat exchanger 15 and the indoor heat exchanger 22, thereby increasing the cooling capacity of the cooling equipment 30 and removing frost that has adhered to the outdoor heat exchanger 15.

[0086] The refrigeration device 1 is equipped with a first service valve 401 on the piping connecting the accumulator 13 and the gas refrigerant flow control valve 61, a second service valve 402 on the piping connecting the suction port of the low-stage compressor 11 and the refrigeration outlet side pressure adjustment mechanism 33, a controller 700 that controls the valve opening and compressor frequency, and a mode that patterns the valve opening during refrigerant charging, and can charge the refrigeration device 1 with an appropriate amount of refrigerant while preventing overload on the compressor, charging refrigerant when the amount of remaining gas in the refrigerant cylinder is low, and reducing the number of service valves.

[0087] [1-3. Effects, etc.] As described above, in this embodiment, the refrigeration device 1 includes a refrigeration circuit connecting a plurality of compressors 11, 12, an outdoor heat exchanger 15, a gas-liquid separator 16, and a plurality of use-side heat exchangers 22, 31, and a controller 700 for controlling the plurality of compressors 11, 12. The plurality of compressors 11, 12 include a low-stage compressor 11 and a high-stage compressor 12. The plurality of use-side heat exchangers 22, 31 include an indoor heat exchanger 22 and a cold-setting heat exchanger 31 having a refrigerant evaporation temperature lower than that of the indoor heat exchanger 22. The indoor heat exchanger 22 is connected to the high-stage compressor 12, and the cold-setting heat exchanger 31 is connected to the high-stage compressor 16. the refrigeration circuit has a first service valve 401 in a gas refrigerant return pipe 60 connected to an intermediate-pressure pipe 80 between the low-stage compressor 11 and the high-stage compressor 12, the first service valve 401 having an external connection port 500A for receiving a supply of refrigerant from the outside, and the controller 700 is capable of executing a first refrigerant charging mode in which the refrigeration circuit is charged with refrigerant supplied from the first service valve 401 by operating the high-stage compressor 12 with the low-stage compressor 11 stopped. This makes it easier to maintain an appropriate pressure difference because low-stage compressor 11 is stopped while refrigerant is being charged through first service valve 401. Therefore, the load on high-stage compressor 12 during refrigerant charging can be reduced. Furthermore, in the present embodiment, the gas refrigerant return pipe 60 where the first service valve 401 is located is a pipe that bypasses the gas refrigerant in the gas-liquid separator 16 to the high-stage compressor 12, and therefore has a pipe diameter of, for example, 2 minutes, which makes it easy to install the first service valve 401.

[0088] As in the present embodiment, the gas refrigerant return pipe 60 is opened and closed by the gas refrigerant flow control valve 61 provided on the opposite side of the external connection port 500A to the medium-pressure pipe 80, and the controller 700 may be configured to close the gas refrigerant flow control valve 61 in the first refrigerant charging mode. This makes it easier to maintain an appropriate pressure difference because low-stage compressor 11 is stopped while refrigerant is being charged from first service valve 401. Therefore, the load on high-stage compressor 12 during refrigerant charging can be reduced.

[0089] As in the present embodiment, the gas refrigerant return pipe 60 is a pipe that connects the gas-liquid separator 16 and the medium-pressure pipe 80, and is opened and closed by a first connection port 501A provided on the medium-pressure pipe 80 side with the external connection port 500A as a reference, and the controller 700 may be configured to execute, as a refrigerant charging mode, an initial refrigerant charging mode in which, with the first connection port 501A closed, all of the compressors 11, 12 are stopped, and a plurality of valves 56, 58, 17, 32 provided in the refrigeration circuit are closed to interrupt the refrigerant flow path in the refrigeration circuit between the gas-liquid separator 16 and all of the compressors 11, 12, thereby charging the gas-liquid separator 16 with refrigerant supplied from the first service valve 401. This allows the refrigeration circuit to be filled with refrigerant without operating any of the compressors 11 and 12. This reduces the load on the compressors 11 and 12 when filling the refrigerant.

[0090] As in this embodiment, the controller 700 may be configured to execute the first refrigerant charging mode after executing the initial refrigerant charging mode. As a result, the refrigerant can be charged in the initial refrigerant charging mode without operating the high-stage compressor 12, and then the refrigerant can be charged by operating the high-stage compressor 12. This makes it easier to maintain an appropriate pressure difference during refrigerant charging, and reduces the load on the high-stage compressor 12.

[0091] As in the present embodiment, the second service valve 402 may be provided in the piping 72 connected to the suction port of the low-stage compressor 11, and the controller 700 may execute a second refrigerant charging mode in which the refrigerant supplied from the second service valve 402 is charged into the refrigeration circuit by operating the high-stage compressor 12 and the low-stage compressor 11 with the gas refrigerant flow control valve 61 open as the refrigerant charging mode after the first refrigerant charging mode. As a result, even when the remaining amount of refrigerant in the refrigerant cylinder is low, refrigerant can be charged via the low-pressure pipe 72 connected to the low-stage compressor 11. This makes it easy to charge the refrigerant to the appropriate amount.

[0092] As in this embodiment, the controller 700 may be configured to terminate the execution of the refrigerant charging mode that is currently being executed when the rate of change of pressure in the refrigeration circuit falls below a predetermined rate of change. This allows the refrigerant charging mode to be terminated when it becomes difficult to charge the refrigeration circuit with refrigerant, making it easier to charge the refrigerant to the appropriate amount.

[0093] As in this embodiment, the controller 700 may be configured to include a notification unit 801, and to cause the notification unit 801 to issue a notification instructing the user to reconnect the external refrigerant supply device connected to the first service valve 401 to the second service valve 402 when the first refrigerant charging mode ends. As a result, even when the remaining amount of refrigerant in the refrigerant cylinder is low, it becomes easy to charge the refrigerant through the low-pressure pipe 72 connected to the low-stage compressor 11. This makes it easy to charge the refrigerant up to the appropriate amount.

[0094] As in this embodiment, the controller 700 may be configured to include a memory unit 703 that stores the set temperature of the refrigeration equipment 30 having the refrigeration heat exchanger 31, and to be able to execute a manual mode in which the compressors 11 and 12 operated in the ongoing refrigerant charging mode are fixed to operate at a frequency specified by an input operation to the input unit 803, and an automatic mode in which the compressors are fixed to operate at a frequency corresponding to the cooling load calculated from the outside air temperature and the set temperature. This makes it possible to fix the operating frequency of the compressors 11 and 12 in the refrigerant charging mode, making it easier to determine whether the amount of refrigerant charged is appropriate. This makes it easier to charge the refrigerant to the appropriate amount.

[0095] As in this embodiment, the refrigeration circuit may be filled with carbon dioxide as the refrigerant. This allows carbon dioxide, which is a refrigerant with a particularly high pressure when being charged, to be charged into the refrigeration circuit without placing a large load on each of the compressors 11 and 12.

[0096] (Embodiment 2) Hereinafter, the second embodiment will be described with reference to Figures 12 to 15. Note that in the following, the description of the same points as in the first embodiment will be omitted, and only the differences will be described. [2-1.Configuration] [2-1-1. Configuration of refrigeration equipment] Fig. 12 is a diagram showing a refrigeration circuit of a refrigeration apparatus 101 in embodiment 2. As shown in Fig. 12, the refrigeration apparatus 101 in embodiment 2 has a first service valve 401 in a pipe 71 that connects the medium-pressure pipe 80 and the outlet side of the indoor heat exchanger 22. In addition, the first service valve 401 is not provided in the gas refrigerant return pipe 60. The other configurations are the same as those of the refrigeration apparatus 1 in embodiment 1. In this embodiment, the pipe 71 corresponds to the "first refrigerant pipe."

[0097] In the second embodiment, the first connection port 501A is connected to the pipe 71 on the side of the on-off valve 23, i.e., the medium-pressure pipe 80, with respect to the external connection port 500A. The second connection port 502A is connected to the pipe 71 on the side of the indoor heat exchanger 22 with respect to the external connection port 500A. In other words, in the second embodiment, the first service valve 401 can open and close the side of the pipe 71 that faces the medium-pressure pipe 80 with respect to the external connection port 500A.

[0098] As in the first embodiment, the refrigeration apparatus 101 has a controller 700 that stores and executes modes for controlling the refrigeration circuit, and has modes that pattern the valve opening and compressor control during refrigerant charging. The modes include, for example, an initial refrigerant charging mode, a first refrigerant amount adjustment mode, and a second refrigerant amount adjustment mode. [2-2. Operation] [2-2-1. Refrigerant charging operation]

[0099] In the second embodiment, too, by having the controller 700 execute each refrigerant charging mode, it is possible to charge an appropriate amount of refrigerant in a refrigeration circuit with a two-stage compression configuration, and furthermore, refrigerant charging can be continued even when the amount of gas remaining in the refrigerant cylinder is small. Note that the order and triggers of the following operations are the same as those in FIGS. 4 and 7 of the first embodiment, but the open / closed states of the valves are different from those in the first embodiment. Also, the setting operations in FIG. 3 are the same as those in the first embodiment, so a description thereof will be omitted.

[0100] 13 is a diagram showing the refrigeration circuit in the initial refrigerant charging mode of the refrigeration device 101. When starting to charge the refrigerant into the refrigeration circuit after evacuation is complete, the first service valve 401 and a refrigerant cylinder filled with the refrigerant to be charged into the circuit are connected by a charge hose via a manifold gauge, and the refrigerant is charged into the gas-liquid separator 16 in the initial refrigerant charging mode.

[0101] In the second embodiment, in step SB1 of FIG. 4, the controller 700 sets the first service valve 401 to the charging mode. In step SB1, the controller 700 fully opens the indoor expansion mechanism 21, the second heating valve 57, and the throttling mechanism 17. In step SB1, the cooling-unit inlet expansion mechanism 32, the first heating valve 52, the second cooling valve 55, the third cooling valve 56, the refrigerant return expansion mechanism 58, and the gas refrigerant flow control valve 61 are fully closed. Also, in step SB1, the second service valve 402 is set to an operating mode that communicates only between the low-stage compressor 11 and the cooling-unit outlet-side pressure adjustment mechanism 33. The operation of these valves is included as a refrigerant charging initial mode in the mode information 705 stored in the memory unit 703, and is automatically performed by the controller 700. In step SB1, the operation of the refrigeration apparatus 101 switches to the refrigerant charging initial mode.

[0102] In step SB1, the refrigeration circuit of refrigeration apparatus 101 is divided into two parts: a part including gas-liquid separator 16 and a part including low-stage compressor 11 and high-stage compressor 12, with valves 32, 52, 55, 56, 58, and 61 and first service valve 401 closed. In the initial refrigerant charging mode, first service valve 401 is in the charging state, so refrigerant supplied from external connection port 500A flows through second connection port 502A and pipe 71 to the indoor heat exchanger 22 side, and then flows into gas-liquid separator 16 through pipes 78, 76, and 79.

[0103] When the pressure P4 in the circuit becomes equal to or exceeds the pressure in the refrigerant cylinder, the pressure difference disappears and refrigerant charging becomes impossible. Therefore, as in the first embodiment, the controller 700 determines whether to switch the mode from the initial refrigerant charging mode to the first refrigerant charging mode (step SB2). If the rate of change per hour of the pressure P4 measured by the second intermediate pressure side pressure sensor 604 becomes smaller than the first predetermined rate of change (step SB2: YES), the controller 700 ends the initial refrigerant charging mode. After the initial refrigerant charging mode ends, the controller 700 switches the refrigerant charging mode to the first refrigerant charging mode (steps SB3 and SB4).

[0104] FIG. 14 illustrates the refrigeration circuit of the refrigeration system 101 in the first refrigerant charging mode. In the first refrigerant charging mode, the controller 700 performs single-stage compression by operating only the high-stage compressor 12, lowering the intermediate pressure in the refrigerant piping connected to the first service valve 401, and creating a pressure difference between the pressure in the refrigerant cylinder and the intermediate pressure to charge the refrigerant. In the first refrigerant charging mode, the service valve 401 is fully open, connecting all of the connection ports 500A, 501A, and 502A, including the external connection port 500A. All valves other than the service valve 401 are opened to the same degree as during cooling operation. In this mode, the second service valve 402 is in an operating mode that connects only the low-stage compressor 11 and the cooling outlet pressure adjustment mechanism 33. The operation of these valves is included as the first refrigerant charging mode in the mode information 705 stored in the memory unit 703, and is automatically controlled by the controller 700.

[0105] In the first refrigerant charging mode, if the amount of refrigerant charged into the circuit increases, the intermediate pressure rises, and the pressure difference with the pressure in the refrigerant cylinder becomes small, making it impossible to charge refrigerant. Therefore, the controller 700 determines whether to switch the mode from the first refrigerant amount adjustment mode to the second refrigerant amount adjustment mode (step SB5). If the rate of change per hour of the high-pressure pressure P3 measured by the high-pressure-side pressure sensor 603 becomes smaller than a second predetermined rate of change (step SB5: YES), the controller 700 terminates the first refrigerant charging mode (step SB6). After the first refrigerant charging mode is terminated, the controller 700 causes the notification unit 801 to issue a notification (step SB7). The notification in step SB7 includes an instruction to reconnect the charge hose connected to the first service valve 401 to the connection port 500B of the second service valve 402.

[0106] After the first refrigerant charging mode ends and notification is made by notification unit 801, a service person or the like reconnects the charge hose connected to the refrigerant cylinder to second service valve 402.

[0107] FIG. 15 is a diagram showing the refrigeration circuit of the refrigeration apparatus 101 in the second refrigerant charging mode. In step SC1 of FIG. 7, the second service valve 402 is fully open, connecting all three connection ports 500A, 501A, and 502A, including the external connection port 500A, and the other valves, including the first service valve 401, are set to the same settings as during cooling operation. The operation of these valves is included as the second refrigerant charging mode in the mode information 705 stored in the memory unit 703 and is automatically performed by the controller 700. Furthermore, the controller 700 operates the low-stage compressor 11 to perform two-stage compression (step SC2) and executes the second refrigerant charging mode. In the second refrigerant charging mode, the low-pressure in the refrigerant pipe connected to the second service valve 402 is reduced to create a pressure difference between the pressure in the refrigerant cylinder and the intermediate pressure, thereby charging the refrigerant. This allows refrigerant to be charged even when the amount of gas remaining in the refrigerant cylinder is low.

[0108] Thereafter, when it is confirmed that the appropriate amount of refrigerant has been charged into the circuit (step SC3: YES), the refrigerant charging is completed (step SC4). To determine whether the appropriate amount of refrigerant has been charged, for example, a determination is made as to whether the high-pressure pressure P3 measured by the high-pressure-side pressure sensor 603 is equal to the target high-pressure pressure. Thereafter, the controller 700 causes the notification unit 801 to notify that the refrigerant charging operation has ended (step SC5).

[0109] In this way, the refrigeration device 101 is equipped with a first service valve 401 in the refrigerant piping connecting the on-off valve 23 and the indoor heat exchanger 22, a second service valve 402 in the piping connecting the suction port of the low-stage compressor 11 and the cooling outlet side pressure adjustment mechanism 33, a controller 700 that controls the valve opening and compressor frequency, and a mode that patterns the valve opening during refrigerant charging, so that the refrigeration device 101 can be charged with an appropriate amount of refrigerant while preventing overload on the compressor and charging refrigerant when the amount of remaining gas in the refrigerant cylinder is low. Furthermore, in the second embodiment, the first service valve 401 can also be used for attaching and detaching the indoor heat exchanger 22 for maintenance, equipment replacement, and the like, so the number of parts of the refrigeration apparatus 101 can be reduced.

[0110] [2-3. Effects, etc.] As described above, in this embodiment, the piping 71 on which the first service valve 401 is provided connects the medium-pressure piping 80 and the indoor heat exchanger 22, and the first service valve 401 is capable of opening and closing the side of the piping 71 that is connected to the medium-pressure piping 80 based on the external connection port 500A. As a result, the first service valve 401 can be used not only when charging the refrigerant but also when attaching and detaching the indoor heat exchanger 22 during maintenance, equipment replacement, etc. This allows the number of parts in the refrigeration device 101 to be reduced.

[0111] (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. Furthermore, it is also possible to combine the components described in the first embodiment above to create new embodiments.

[0112] In the above-described embodiment, the refrigeration device 1 includes one indoor heat exchanger 22 and one cooling-use heat exchanger 31. However, the present invention is not limited to this, and the refrigeration device 1 may omit the indoor heat exchanger 22 and include multiple cooling-use heat exchangers 31. In other words, the refrigeration device 1 may omit the indoor unit 20 and include multiple cooling devices 30. In this case, the evaporating temperature ranges of the plurality of refrigeration heat exchangers 31 are different from one another. Of the plurality of refrigeration heat exchangers 31, the refrigeration heat exchanger 31 with a higher evaporating temperature range is connected to the inlet side of the high-stage compressor 12, and the refrigeration heat exchanger 31 with a lower evaporating temperature range is connected to the inlet side of the low-stage compressor 11.

[0113] For example, when the refrigeration system 1 includes a cooling unit 30 set to the freezing temperature range and a cooling unit 30 set to the refrigeration temperature range, the cooling heat exchanger 31 in the cooling unit 30 set to the refrigeration temperature range is connected to the inlet side of the high-stage compressor 12. On the other hand, the cooling heat exchanger 31 in the cooling unit 30 set to the freezing temperature range is connected to the inlet side of the low-stage compressor 11.

[0114] In the above-described embodiment, a plurality of utilization side heat exchangers connected to the inlet side of the high-stage compressor 12 may be provided in parallel on the pipes 78 and 71. Similarly, a plurality of utilization side heat exchangers connected to the inlet side of the low-stage compressor 11 may be provided in parallel on the pipes 77 and 72.

[0115] 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 device 1 includes a plurality of indoor units 20. Also in this case, one or more indoor heat exchangers 22 and one or more cooling heat exchangers 31 may be provided in parallel to one another in the piping 78 and the piping 71.

[0116] A plurality of chilled-use heat exchangers 31 may be provided in parallel to one another on the piping 77 and the piping 72. In this case, a chilled-use inlet-side expansion mechanism 32 may be provided on the inlet side of each chilled-use heat exchanger 31. In this case, at least one of the chilled-use heat exchangers 31 provided in parallel to one another on the piping 77 and the piping 72 may have an evaporation temperature range different from that of the other chilled-use heat exchangers 31.

[0117] In the first and second embodiments, it has been described that each of the service valves 401, 402 can be electronically controlled, but this is merely an example. The configuration of each of the service valves 401, 402 may be configured to be manually switched. That is, the operation of each of the service valves 401, 402 in steps SB1, SB3, SB6, SC1, and SC4 may be configured to be executed manually. In this case, for example, in steps SB1, SB3, SB6, SC1, and SC4, a notification unit 801 or the like may be used to issue an instruction to switch the configuration of each of the service valves 401, 402.

[0118] In the first and second embodiments, notification unit 801 has been described as a display including a liquid crystal panel or the like, but this is merely an example. Notification unit 801 may be configured to issue an instruction to change the connection of the charge hose of the refrigerant cylinder from first service valve 401 to second service valve 402. For example, notification unit 801 may be a speaker that issues an instruction to change the connection of the charge hose by voice. Notification unit 801 may also be an LED or the like that issues an instruction to change the connection of the charge hose by light.

[0119] In the first embodiment, it has been described that the first service valve 401 is disposed between the gas refrigerant flow control valve 61 and the accumulator 13, that is, the gas refrigerant flow control valve 61 is located closer to the gas-liquid separator 16 than the first service valve 401. However, this is just one example. For example, the first service valve 401 may be configured to be arranged on the gas refrigerant return pipe 60 closer to the gas-liquid separator 16 than the gas refrigerant flow rate control valve 61. In this case, the first connection port 501A, which is closed when the first service valve 401 is in the filling mode, is connected to the gas refrigerant return pipe 60 on the gas-liquid separator 16 side of the external connection port 500A. Furthermore, the second connection port 502A, which is always open, is connected to the gas refrigerant return pipe 60 on the medium-pressure pipe 80 side of the external connection port 500A. In this case, the first connection port 501A corresponds to a "first opening / closing unit" that opens and closes the gas refrigerant return pipe 60. In this case, in the initial refrigerant charging mode, the gas refrigerant flow control valve 61 is closed and the first service valve 401 is fully open. In the first refrigerant charging mode, the gas refrigerant flow control valve 61 is opened and the first service valve 401 is in the charging mode, thereby closing the first connection port 501A. As a result, similar to the first embodiment, the initial refrigerant charging mode, the first refrigerant charging mode, and the second refrigerant charging mode can be selectively used without increasing the number of parts.

[0120] In the first and second embodiments, the refrigeration circuit of the refrigeration apparatus 1, 101 is described as being provided with the first service valve 401 and the second service valve 402, but this is merely an example. For example, instead of providing the second service valve 402, a bypass pipe may be branched off near the first service valve 401, connected to the suction side of the low-stage compressor 11, and an on-off valve may be provided in the bypass pipe. In this case, by opening the on-off valve provided in the bypass pipe only in the second refrigerant charging mode, it is not necessary to change the connection of the charge hose, and the work of charging the refrigerant is made easier.

[0121] In the first embodiment, when each refrigerant charging mode is executed in the automatic mode, the compressors 11 and 12 are operated at the frequency calculated in step SA5. However, this is just an example. For example, in the automatic mode, the compressors 11 and 12 may be configured to operate at full capacity and fix the frequency.

[0122] The controller 700 in the present disclosure may be any device capable of controlling the device in the present disclosure. When describing the subject matter of the invention, the device in the present disclosure may be referred to as a control means, a control unit, or similar terms in addition to the controller 700. The controller can be realized in various forms. For example, a processor may be used as the controller 700. Using a processor as the controller 700 enables various processes to be performed by loading a program from a storage medium storing the program into the processor and executing the program. This allows the processing content to be changed by modifying the program stored in the storage medium, thereby increasing the flexibility of changing the control content. Examples of processors include a central processing unit (CPU) and a microprocessing unit (MPU). Examples of storage media include a hard disk, flash memory, and optical disk. Alternatively, the controller 700 may be wired logic, which does not allow rewriting of programs. Using wired logic as the controller 700 is effective in improving processing speed. Examples of wired logic include an application-specific integrated circuit (ASIC). The controller 700 may also be realized by combining a processor and wired logic. By combining a processor and wired logic, the controller 700 can improve processing speed while increasing the degree of freedom in software design. The controller 700 and a circuit having a different function from the controller 700 may be configured with a single semiconductor element. An example of a circuit having a different function is an A / D-D / A conversion circuit. The controller 700 may also be configured with a single semiconductor element or multiple semiconductor elements. When configured with multiple semiconductor elements, each control described in the claims may be realized by a different semiconductor element. The controller 700 may also be configured with a semiconductor element and a passive component such as a resistor or a capacitor.

[0123] Furthermore, for example, the step units of operation shown in Figures 3, 4, and 7 are divided according to the main processing content in order to make it easier to understand the operation of each part of the refrigeration device 1, and the present disclosure is not limited by the way in which the processing units are divided or their names.

[0124] 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, etc. may be made within the scope of the claims or their equivalents.

[0125] [Configuration supported by the above embodiment] The above embodiment supports the following configurations.

[0126] a first service valve in a first refrigerant pipe connected to a medium-pressure pipe between the low-stage compressor and the high-stage compressor, the first service valve having an external connection port for receiving a supply of refrigerant from an outside; and the controller is capable of executing a first refrigerant charging mode in which the high-stage compressor is operated with the low-stage compressor stopped, thereby charging the refrigeration circuit with refrigerant supplied from the first service valve. This stops the low-stage compressor while refrigerant is being charged through the first service valve, making it easier to maintain an appropriate pressure difference, thereby reducing the load on the compressor during refrigerant charging.

[0127] (Technology 2) The refrigeration device according to Technology 1, characterized in that the first refrigerant piping is opened and closed by a first opening and closing unit provided on the opposite side of the medium-pressure piping with respect to the external connection port, and the controller closes the first opening and closing unit in the first refrigerant charging mode. This stops the low-stage compressor while refrigerant is being charged through the first service valve, making it easier to maintain an appropriate pressure difference, thereby reducing the load on the compressor during refrigerant charging.

[0128] (Technology 3) The refrigeration device according to Technology 1 or 2, characterized in that the first refrigerant piping is a piping that connects the gas-liquid separator and the medium-pressure piping, and is opened and closed by a second opening / closing unit provided on the medium-pressure piping side with the external connection port as a reference, and the controller is capable of executing, as the refrigerant charging mode, an initial refrigerant charging mode in which, with the second opening / closing unit closed, all of the compressors are stopped, a plurality of valves provided in the refrigeration circuit are closed, and a refrigerant flow path in the refrigeration circuit is separated between the gas-liquid separator and all of the compressors, thereby charging the gas-liquid separator with refrigerant supplied from the first service valve. This allows the refrigeration circuit to be filled with refrigerant without operating any of the compressors, thereby reducing the load on each compressor during refrigerant filling.

[0129] (Technical 4) The refrigeration device according to Technical 3, wherein the controller executes the first refrigerant charging mode after executing the initial refrigerant charging mode. This allows refrigerant to be charged in the initial refrigerant charging mode without operating the high-stage compressor, and then the high-stage compressor is operated to charge the refrigerant, making it easier to maintain an appropriate pressure difference and reducing the load on the compressor during refrigerant charging.

[0130] (Technology 5) The refrigeration device according to any one of Technologies 2 to 4, characterized in that a second service valve is provided in a low-pressure pipe connected to an intake port of the low-stage compressor, and the controller is capable of executing a second refrigerant charging mode in which the refrigeration circuit is filled with refrigerant supplied from the second service valve by operating the high-stage compressor and the low-stage compressor with the first opening / closing unit open as the refrigerant charging mode after the first refrigerant charging mode. This allows refrigerant to be charged through the low-pressure pipe connected to the low-stage compressor even when the refrigerant tank is low in quantity, making it easy to charge the tank to the appropriate amount of refrigerant.

[0131] (Technology 6) A refrigeration device according to any one of Techniques 1 to 5, wherein the controller terminates the execution of the refrigerant charging mode when the rate of change of pressure in the refrigeration circuit falls below a predetermined rate of change. This allows the refrigerant charging mode to be terminated when it becomes difficult to charge the refrigeration circuit with refrigerant, making it easier to charge the refrigerant to the appropriate amount.

[0132] (Technology 7) The refrigeration device according to Technology 5, further comprising a notification unit, wherein the controller causes the notification unit to issue a notification instructing the user to reconnect an external refrigerant supply device connected to the first service valve to the second service valve when the first refrigerant charging mode ends. This makes it easier to fill the refrigerant tank with the appropriate amount of refrigerant through the low-pressure pipe connected to the low-stage compressor, even when the remaining amount of refrigerant in the tank is low.

[0133] (Technology 8) The refrigeration device according to any one of Technologies 1 to 7, further comprising a memory unit that stores a set temperature of the device having the second use-side heat exchanger, and the controller is capable of executing a manual mode in which the compressor operated in the refrigerant charging mode currently being executed is operated at a fixed frequency specified by an input operation to an input unit, and an automatic mode in which the compressor is operated at a fixed frequency corresponding to a cooling load calculated from an outside air temperature and the set temperature. This allows the operating frequency of the compressor in the refrigerant charging mode to be fixed, making it easier to determine whether the amount of refrigerant charged is appropriate, and therefore makes it easier to charge the refrigerant to the appropriate amount.

[0134] (Technical 9) The refrigeration device according to Technical 1, characterized in that the first refrigerant piping connects the medium-pressure piping and the outlet side of the first use-side heat exchanger, and the first service valve is capable of opening and closing the medium-pressure piping side of the first refrigerant piping based on the external connection port. This allows the first service valve to be used not only when charging refrigerant, but also when attaching and detaching the first user-side heat exchanger during maintenance, equipment replacement, etc. This reduces the number of parts in the refrigeration device.

[0135] (Technology 10) The refrigeration device according to any one of Technologies 1 to 9, wherein the refrigeration circuit is filled with carbon dioxide as a refrigerant. This allows carbon dioxide, a refrigerant that has a particularly high pressure when filled, to be filled into the refrigeration circuit without placing a large load on the compressor. [Industrial Applicability]

[0136] The present disclosure is applicable to refrigeration devices, specifically to refrigeration devices installed in stores such as convenience stores and supermarkets to provide air conditioning and cooling. [Explanation of symbols]

[0137] 1 Refrigeration equipment 10 Outdoor unit 11 Low-stage compressor (compressor) 12 High-stage compressor (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 (1st user side heat exchanger) 23 On-off valve 30 Refrigeration equipment 31 Refrigeration heat exchanger (second user side heat exchanger) 32 Inlet expansion mechanism for refrigeration 33 Refrigeration outlet pressure adjustment mechanism 40 Piping 41 First heating pipe 42 First outdoor return pipe 50 First switching mechanism 51 First cooling valve 52 First heating valve 53 Outdoor refrigerant return valve 54 Second switching mechanism 55 Second cooling valve 56 Third cooling valve 57 Second heating valve 58 Refrigerant return expansion mechanism 59 Check valve 60 Gas refrigerant return piping (first refrigerant piping) 61 Gas refrigerant flow control valve (first opening / closing section) 71 Piping (first refrigerant piping) 72 Piping (low pressure piping) 73 First Pipe 74 Second Pipe 75 Third Pipe 76 Fourth Pipe 77 Piping 78 Piping 79 Piping 80 Medium pressure piping 95 Outdoor unit I / F 101 Refrigeration equipment 401 First service valve 402 Second service valve 500A external connection port 500B external connection port 501A First connection port 501B 1st connection port 502A Second connection port 502B Second connection port 601 Low pressure side pressure sensor 602 Intermediate pressure side pressure sensor 603 High-side pressure sensor 604 Second intermediate pressure side pressure sensor 700 Controller 701 Control Unit 703 Storage section 705 Mode Information 707 Switching Information 709 Configuration Information 801 Notification Department 803 Input section A Connection B Connection C Connection D Connection

Claims

1. a refrigeration circuit connecting a plurality of compressors, a heat source side heat exchanger, a gas-liquid separator, and a plurality of user side heat exchangers; a controller for controlling the plurality of compressors, the plurality of compressors include a low-stage compressor and a high-stage compressor, the plurality of use-side heat exchangers include a first use-side heat exchanger and a second use-side heat exchanger having a refrigerant evaporation temperature lower than that of the first use-side heat exchanger, the first utilization-side heat exchanger is connected to the high-stage compressor, the second utilization-side heat exchanger is connected to the low-stage compressor, the refrigeration circuit has a first service valve in a first refrigerant pipe connected to an intermediate-pressure pipe between the low-stage compressor and the high-stage compressor; the first service valve has an external connection port for receiving a supply of refrigerant from the outside, the controller is capable of executing a first refrigerant charging mode in which the refrigeration circuit is charged with refrigerant supplied from the first service valve by operating the high-stage compressor while stopping the low-stage compressor, as a refrigerant charging mode. A refrigeration device characterized by:

2. the first refrigerant pipe is opened and closed by a first opening and closing unit provided on the opposite side of the medium-pressure pipe with respect to the external connection port, the controller closes the first opening / closing unit in the first refrigerant charging mode.

2. The refrigeration system according to claim 1.

3. the first refrigerant pipe is a pipe connecting the gas-liquid separator and the medium-pressure pipe, and is opened and closed by a second opening and closing unit provided on the medium-pressure pipe side with respect to the external connection port; The controller is capable of executing, as the refrigerant charging mode, a refrigerant charging initial mode in which, with the second opening / closing unit closed, all of the compressors are stopped, a plurality of valves provided in the refrigeration circuit are closed, and a refrigerant flow path in the refrigeration circuit is separated between the gas-liquid separator and all of the compressors, thereby charging the gas-liquid separator with refrigerant supplied from the first service valve.

2. The refrigeration system according to claim 1.

4. the controller executes the first refrigerant charging mode after executing the initial refrigerant charging mode.

4. The refrigeration system according to claim 3.

5. a second service valve is provided in a low-pressure pipe connected to an intake port of the low-stage compressor; the controller is capable of executing, after the first refrigerant charging mode, a second refrigerant charging mode in which the refrigeration circuit is charged with refrigerant supplied from the second service valve by operating the high-stage compressor and the low-stage compressor with the first opening / closing unit open as the refrigerant charging mode.

3. The refrigeration system according to claim 2.

6. the controller terminates the execution of the refrigerant charging mode when a rate of change in pressure in the refrigeration circuit falls below a predetermined rate of change.

6. The refrigeration system according to claim 1.

7. A notification unit is provided, the controller causes the notification unit to issue a notification instructing an operation to change the connection of an external refrigerant supply tool connected to the first service valve to the second service valve when the first refrigerant charging mode is completed; 6. The refrigeration system according to claim 5.

8. a storage unit that stores a set temperature of the device having the second use-side heat exchanger, The controller is capable of executing a manual mode in which the compressor operated in the refrigerant charging mode is fixed to a frequency designated by an input operation on an input unit, and an automatic mode in which the compressor is fixed to a frequency corresponding to a cooling load calculated from an outside air temperature and the set temperature.

7. The refrigeration system according to claim 6.

9. the first refrigerant pipe connects the intermediate-pressure pipe and an outlet side of the first use-side heat exchanger, the first service valve is capable of opening and closing the medium-pressure piping side of the first refrigerant piping relative to the external connection port, 2. The refrigeration system according to claim 1.

10. The refrigeration circuit is filled with carbon dioxide as a refrigerant.

6. The refrigeration system according to claim 1.

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