Refrigeration cycle device

Abstract

To provide a refrigeration cycle device capable of suppressing refrigerant leakage in a utilization unit, while suppressing increase in production cost.SOLUTION: A refrigeration cycle device 100 includes a utilization unit 1, a heat source unit 2, a gas refrigerant connection pipe 6, and a first cutoff valve unit 3. The utilization unit 1 includes a utilization heat exchanger 11. The heat source unit 2 includes a compressor 21 and a heat source heat exchanger 23. The gas refrigerant connection pipe 6 is provided between the compressor 21 and the utilization heat exchanger 11. The first cutoff valve unit 3 is provided between the gas refrigerant connection pipe 6 and the utilization unit 1, and cuts off a refrigerant flowing between the gas refrigerant connection pipe 6 and the utilization unit 1. The first cutoff valve unit 3 includes: a plurality of first flow dividing pipes 31 in which the refrigerant flowing between the gas refrigerant connection pipe 6 and the utilization unit 1 flows in parallel with each other; and a cutoff valve 33 provided at each of the plurality of first flow dividing pipes 31.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This relates to a refrigeration cycle device. [Background technology]

[0002] The air conditioning system disclosed in Patent Document 1 (Patent Publication No. 2020-030043) is provided with a shutoff valve between the indoor unit and the liquid piping and between the indoor unit and the gas piping. When a refrigerant leak is detected in the indoor unit, the air conditioning system of Patent Document 1 closes the shutoff valve to shut off the flow of refrigerant to the indoor unit, thereby preventing further refrigerant leakage in the space to be air-conditioned. Summary of the Invention [Problem to be solved by the invention]

[0003] In the air conditioning system of Patent Document 1, the refrigerant is shut off by only one shutoff valve for each of the liquid piping and the gas piping. Therefore, when the capacity of the indoor unit is large, there is a risk that the shutoff valve will not be able to sufficiently shut off the flow of the refrigerant.

[0004] It may be possible to shut off the flow of refrigerant in a large-capacity indoor unit with a single shutoff valve by using a large-diameter shutoff valve, but large-diameter shutoff valves are expensive and tend to increase manufacturing costs.

[0005] An object of the present disclosure is to provide a refrigeration cycle device that can suppress refrigerant leakage in a utilization unit while suppressing an increase in manufacturing costs. [Means for solving the problem]

[0006] A refrigeration cycle apparatus according to a first aspect includes a utilization unit, a heat source unit, a gas refrigerant communication pipe, and a first shutoff valve unit.

[0007] The utilization unit has a utilization heat exchanger. The heat source unit has a compressor and a heat source heat exchanger. The gas refrigerant communication pipe is provided between the compressor and the utilization heat exchanger. The first shutoff valve unit is provided between the gas refrigerant communication pipe and the utilization unit, and shuts off the refrigerant flowing between the gas refrigerant communication pipe and the utilization unit.

[0008] The first shutoff valve unit has a plurality of first branch pipes through which refrigerant flowing between the gas refrigerant communication pipe and the utilization units flows in parallel, and a shutoff valve provided in each of the plurality of first branch pipes.

[0009] In the refrigeration cycle device, the refrigerant flowing between the gas refrigerant communication pipe and the utilization units is diverted to multiple first diverter pipes, so the amount of refrigerant passing through each shutoff valve is smaller than when the refrigerant is not diverted. This allows the shutoff valves to be designed to be small, suppressing an increase in manufacturing costs that would otherwise be associated with larger shutoff valves. Therefore, the refrigeration cycle device can suppress refrigerant leakage in the utilization units while suppressing an increase in manufacturing costs.

[0010] A refrigeration cycle apparatus according to a second aspect is the refrigeration cycle apparatus according to the first aspect, further comprising a liquid refrigerant communication pipe and a second shutoff valve unit. The liquid refrigerant communication pipe is provided between the utilization heat exchanger and the heat source heat exchanger. The second shutoff valve unit is provided between the liquid refrigerant communication pipe and the utilization unit, and shuts off the refrigerant flowing between the liquid refrigerant communication pipe and the utilization unit.

[0011] The second shutoff valve unit has a plurality of second branch pipes through which the refrigerant flowing between the liquid refrigerant communication pipe and the utilization units flows in parallel, and a plurality of shutoff valves provided in each of the second branch pipes.

[0012] Since the present refrigeration cycle apparatus also has a shutoff valve between the liquid refrigerant communication pipe and the utilization unit, it is possible to more effectively prevent refrigerant leakage from the utilization unit while suppressing an increase in manufacturing costs.

[0013] A refrigeration cycle apparatus according to a third aspect is the refrigeration cycle apparatus according to the first or second aspect, further comprising a control unit for controlling the shutoff valves. When a refrigerant leak is detected in a utilization unit, the control unit closes all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leak was detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe.

[0014] In the event that a refrigerant leak occurs, the present refrigeration cycle apparatus can suppress the refrigerant leak from the utilization unit.

[0015] A refrigeration cycle apparatus according to a fourth aspect is the refrigeration cycle apparatus according to any one of the first aspect to the third aspect, wherein the control unit has a utilization unit control unit, a heat source unit control unit, and a shutoff valve control unit.

[0016] The utilization unit control unit is provided in the utilization unit. The heat source unit control unit is provided in the heat source unit. The shutoff valve control unit controls the shutoff valve.

[0017] When a refrigerant leak is detected in a utilization unit, the utilization unit control unit transmits a first signal to the heat source unit control unit. When the heat source unit control unit receives the first signal, it transmits a second signal to the shutoff valve control unit. When the shutoff valve control unit receives the second signal, it closes all shutoff valves that shut off the refrigerant flowing between the utilization unit in which a refrigerant leak was detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe.

[0018] In this refrigeration cycle device, the shut-off valve control unit closes all corresponding shut-off valves based on a signal sent from the utilization unit control unit itself when a refrigerant leak is detected, thereby preventing the erroneous closure of shut-off valves corresponding to utilization units where no refrigerant leak is occurring.

[0019] A refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to any one of the first aspect to the third aspect, wherein the control unit has a utilization unit control unit and a shutoff valve control unit.

[0020] The utilization unit control unit is provided in the utilization unit. The shutoff valve control unit controls the shutoff valve.

[0021] When a refrigerant leak is detected in a utilization unit, the utilization unit control unit transmits a third signal to the shutoff valve control unit. When the shutoff valve control unit receives the third signal, it closes all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leak was detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe.

[0022] In this refrigeration cycle apparatus, the shutoff valve control unit closes all corresponding shutoff valves based on a signal sent from the utilization unit control unit itself that detected a refrigerant leak, thereby preventing the erroneous closing of a shutoff valve corresponding to a utilization unit that is not leaking refrigerant. Therefore, the refrigeration cycle apparatus can prevent refrigerant leakage from a utilization unit that has experienced a refrigerant leak.

[0023] A refrigeration cycle apparatus according to a sixth aspect is the refrigeration cycle apparatus according to any one of the first to third aspects, further comprising a control unit 7 for controlling the shutoff valves. When the control unit detects an abnormality in any one of the plurality of shutoff valves, it closes all the remaining shutoff valves and then stops operation of any one of the utilization units and the heat source unit.

[0024] According to the present refrigeration cycle device, it is possible to prevent the shutoff valve from failing to operate due to refrigerant leakage.

[0025] A refrigeration cycle apparatus according to a seventh aspect is the refrigeration cycle apparatus according to any one of the first aspect to the sixth aspect, wherein the rated capacity of the utilization unit is 10 horsepower or more.

[0026] The present refrigeration cycle apparatus can suppress an increase in manufacturing costs even if it has a utilization unit with a large rated capacity of 10 horsepower or more.

[0027] A refrigeration cycle apparatus according to an eighth aspect is the refrigeration cycle apparatus according to any one of the first aspect to the seventh aspect, in which the shutoff valve is a needle valve.

[0028] Since the present refrigeration cycle apparatus can prevent the diameter of the shutoff valve from increasing, even if a needle valve is used for the shutoff valve, it is possible to prevent refrigerant leakage in the utilization unit while suppressing an increase in manufacturing costs. [Brief description of the drawings]

[0029] [Figure 1] 1 is a schematic configuration diagram of a refrigeration cycle device 100 according to a first embodiment. [Diagram 2] 1 is a block diagram of a control unit 7 of a refrigeration cycle apparatus 100 according to a first embodiment. [Diagram 3] 4 is a flowchart showing a control flow when a refrigerant leaks. [Figure 4] 4 is a block diagram of a control unit 7 of a refrigeration cycle apparatus 100 according to a modified example A. FIG. [Diagram 5] FIG. 1 is a schematic configuration diagram of a refrigeration cycle device 100a according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] First Embodiment (1) Overall structure The refrigeration cycle apparatus 100 performs air conditioning operations (specifically, cooling operation and heating operation) in a space to be air-conditioned by performing a vapor compression refrigeration cycle. The space to be air-conditioned is, for example, a space inside a building such as an office building, a commercial facility, or a residence. Note that the refrigeration cycle apparatus is merely one example of a refrigerant cycle apparatus, and the heat exchanger of the present disclosure may be used in other refrigerant cycle apparatus, for example, a refrigerator, a freezer, a water heater, a floor heating apparatus, or the like.

[0031] The refrigeration cycle device 100 mainly includes two utilization units 1, one heat source unit 2, two first shutoff valve units 3, two second shutoff valve units 4, one liquid refrigerant connection pipe 5, one gas refrigerant connection pipe 6, and one control unit 7. The liquid refrigerant connection pipe 5 and the gas refrigerant connection pipe 6 are refrigerant connection pipes that connect the utilization units 1 and the heat source units 2. In the refrigeration cycle device 100, the utilization units 1 and the heat source units 2 are connected via the liquid refrigerant connection pipe 5 and the gas refrigerant connection pipe 6 to form a refrigerant circuit 8. In other words, the liquid refrigerant connection pipe 5 is provided between the utilization heat exchanger 11 and the heat source heat exchanger 23 (both described later). The gas refrigerant connection pipe 6 is provided between the compressor 21 (described later) and the utilization heat exchanger 11.

[0032] The two utilization units 1 are installed in rooms A and B, which are spaces to be air-conditioned.

[0033] (2) Detailed configuration (2-1) Usage Unit 1 1, the utilization unit 1 mainly includes a utilization heat exchanger 11, a utilization fan 12, a utilization expansion mechanism 13, a liquid refrigerant pipe 14, a gas refrigerant pipe 15, and a refrigerant sensor 16. The rated capacity of the utilization unit 1 is 10 horsepower or more.

[0034] Hereinafter, when it is necessary to distinguish between the two utilization units 1, the utilization unit 1 installed in room A will be referred to as utilization unit 1a, and the utilization unit 1 installed in room B will be referred to as utilization unit 1b. Similarly, the equipment included in utilization unit 1a may be indicated by adding the suffix a to the reference symbol, and the equipment included in utilization unit 1b may be indicated by adding the suffix b to the reference symbol.

[0035] The number of utilization units 1 is not limited to two, but may be three or more.

[0036] (2-1-1) Utilized heat exchanger 11 The utilization heat exchanger 11 exchanges heat between the refrigerant and air carried by the airflow generated by the utilization fan 12. One end of the utilization heat exchanger 11 is connected to the liquid refrigerant connection pipe 5 via a liquid refrigerant pipe 14, and the other end is connected to the gas refrigerant connection pipe 6 via a gas refrigerant pipe 15.

[0037] (2-1-2) 12 fans in use The utilization fan 12 supplies air to the utilization heat exchanger 11 .

[0038] (2-1-3) Expansion mechanism used 13 The utilization expansion mechanism 13 adjusts the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 14. The utilization expansion mechanism 13 is provided in the liquid refrigerant pipe 14.

[0039] (2-1-4) Refrigerant sensor 16 The refrigerant sensor 16 detects the refrigerant in the space to be air conditioned, which is the installation location of the utilization unit 1. In other words, the refrigerant sensor 16 detects leakage of the refrigerant in the space to be air conditioned.

[0040] (2-2) Heat source unit 2 The heat source unit 2 mainly includes a compressor 21 , a four-way switching mechanism 22 , a heat source heat exchanger 23 , a heat source expansion mechanism 24 , a liquid side shut-off valve 25 , a gas side shut-off valve 26 , and a heat source fan 27 .

[0041] The heat source unit 2 has a suction pipe P1, a discharge pipe P2, a first gas refrigerant pipe P3, a liquid refrigerant pipe P4, and a second gas refrigerant pipe P5 as refrigerant pipes connecting each device constituting the refrigerant circuit 8. The suction pipe P1 connects the four-way switching mechanism 22 and the suction side of the compressor 21. The discharge pipe P2 connects the discharge side of the compressor 21 and the four-way switching mechanism 22. The first gas refrigerant pipe P3 connects the four-way switching mechanism 22 and the gas side of the heat source heat exchanger 23. The liquid refrigerant pipe P4 connects the liquid side of the heat source heat exchanger 23 and the liquid side shutoff valve 25. The heat source expansion mechanism 24 is provided in the liquid refrigerant pipe P4. The second gas refrigerant pipe P5 connects the four-way switching mechanism 22 and the gas side shutoff valve 26.

[0042] (2-2-1) Compressor 21 The compressor 21 draws in low-pressure refrigerant in a refrigeration cycle from a suction pipe P1, compresses the refrigerant by a compression mechanism (not shown), and discharges the refrigerant to a discharge pipe P2.

[0043] (2-2-2) Four-way switching mechanism 22 The four-way switching mechanism 22 switches the flow direction of the refrigerant to change the state of the refrigerant circuit 8 between a cooling operation state and a heating operation state. When the refrigerant circuit 8 is in a cooling operation state, the heat source heat exchanger 23 functions as a refrigerant radiator (condenser), and the utilization heat exchanger 11 functions as an evaporator of the refrigerant. When the refrigerant circuit 8 is in a heating operation state, the heat source heat exchanger 23 functions as a refrigerant evaporator, and the utilization heat exchanger 11 functions as a refrigerant condenser.

[0044] When the four-way switching mechanism 22 sets the refrigerant circuit 8 to a cooling operation state, the four-way switching mechanism 22 connects the suction pipe P1 to the second gas refrigerant pipe P5 and the discharge pipe P2 to the first gas refrigerant pipe P3 (see the solid lines in the four-way switching mechanism 22 in FIG. 1). When the four-way switching mechanism 22 sets the refrigerant circuit 8 to a heating operation state, the four-way switching mechanism 22 connects the suction pipe P1 to the first gas refrigerant pipe P3 and the discharge pipe P2 to the second gas refrigerant pipe P5 (see the dashed lines in the four-way switching mechanism 22 in FIG. 1).

[0045] (2-2-3) Heat source heat exchanger 23 The heat source heat exchanger 23 exchanges heat between the refrigerant flowing inside and a heat source (for example, the air in the location where the heat source unit 2 is installed).

[0046] (2-2-4) Heat source expansion mechanism 24 The heat source expansion mechanism 24 adjusts the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe P4.

[0047] (2-2-5) Liquid side shutoff valve 25 and gas side shutoff valve 26 The liquid side shut-off valve 25 is a valve provided at the connection between the liquid refrigerant pipe P4 and the liquid refrigerant connection pipe 5. The gas side shut-off valve 26 is a valve provided at the connection between the second gas refrigerant pipe P5 and the gas refrigerant connection pipe 6. The liquid side shut-off valve 25 and the gas side shut-off valve 26 are open when the refrigeration cycle apparatus 100 is operating.

[0048] (2-2-6) Heat source fan 27 The heat source fan 27 supplies outside air, which is a heat source, to the heat source heat exchanger 23 .

[0049] (2-3) First shutoff valve unit 3 The first shutoff valve unit 3 is provided between the gas refrigerant communication pipe 6 and the utilization unit 1, and shuts off the refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization unit 1. The first shutoff valve unit 3 is disposed outside the utilization unit 1.

[0050] The first shutoff valve unit 3 has a plurality of first branch pipes 31 and a plurality of first shutoff valves 33 .

[0051] The multiple first branch pipes 31 are pipes through which the refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization units 1 flows in parallel with each other. The refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization units 1 is branched to flow through the multiple first branch pipes 31. In this embodiment, the first shutoff valve unit 3 has two first branch pipes 31.

[0052] A first shutoff valve 33 is provided in each of the multiple first branch pipes 31. The flow of refrigerant in the first branch pipes 31 is shut off when the first shutoff valves 33 are closed. In other words, the flow of refrigerant between the utilization units 1 and the gas refrigerant communication pipe 6 is shut off when all of the first shutoff valves 33 are closed. If the refrigerant sensor 16 does not detect a refrigerant leak, the first shutoff valves 33 will, in principle, remain open. In this embodiment, the first shutoff valve unit 3 has two first shutoff valves 33.

[0053] Although not limited thereto, the first shutoff valve 33 is a needle valve. Note that the number of first branch pipes 31 and first shutoff valves 33 is not limited to two, and may be three or more.

[0054] Hereinafter, when it is necessary to distinguish between the two first shutoff valve units 3, the first shutoff valve unit 3 installed in room A will be referred to as the first shutoff valve unit 3a, and the first shutoff valve unit 3 installed in room B will be referred to as the first shutoff valve unit 3b. Similarly, the equipment included in the first shutoff valve unit 3a will be indicated by adding the suffix a to the reference symbol, and the equipment included in the first shutoff valve unit 3b will be indicated by adding the suffix b to the reference symbol.

[0055] (2-4) Second shutoff valve unit 4 The second shutoff valve unit 4 is provided between the liquid refrigerant connection pipe 5 and the utilization unit 1, and shuts off the refrigerant flowing between the liquid refrigerant connection pipe 5 and the utilization unit 1. The second shutoff valve unit 4 is disposed outside the utilization unit 1.

[0056] The second shutoff valve unit 4 has a plurality of second branch pipes 41 and a plurality of second shutoff valves 43 .

[0057] The multiple second branch pipes 41 are pipes through which the refrigerant flowing between the liquid refrigerant connection pipe 5 and the utilization units 1 flows in parallel with each other. The refrigerant flowing between the liquid refrigerant connection pipe 5 and the utilization units 1 is branched to flow through the multiple second branch pipes 41. In this embodiment, the second shutoff valve unit 4 has two second branch pipes 41.

[0058] A second shutoff valve 43 is provided in each of the multiple second branch pipes 41. The flow of refrigerant in the second branch pipes 41 is shut off when the second shutoff valves 43 are closed. In other words, the flow of refrigerant between the utilization units 1 and the liquid refrigerant communication pipe 5 is shut off when all of the second shutoff valves 43 are closed. If the refrigerant sensor 16 does not detect a refrigerant leak, the second shutoff valves 43 will, in principle, remain open. In this embodiment, the second shutoff valve unit 4 has two second shutoff valves 43.

[0059] Although not limited thereto, the second shutoff valve 43 is a needle valve. Note that the number of the second branch pipes 41 and the second shutoff valves 43 is not limited to two, and may be three or more.

[0060] Hereinafter, when it is necessary to distinguish between the two second shutoff valve units 4, the second shutoff valve unit 4 installed in room A will be referred to as the second shutoff valve unit 4a, and the second shutoff valve unit 4 installed in room B will be referred to as the second shutoff valve unit 4b. Similarly, the equipment included in the second shutoff valve unit 4a will be indicated by adding the suffix a to the reference symbol, and the equipment included in the second shutoff valve unit 4b will be indicated by adding the suffix b to the reference symbol.

[0061] (2-5) Control Unit 7 The control unit 7 controls the operation of various devices constituting the refrigeration cycle apparatus 100. As shown in Fig. 2, the control unit 7 is electrically connected to the compressor 21, the four-way switching mechanism 22, the heat-source expansion mechanism 24, the heat-source fan 27, the utilization fan 12, the utilization expansion mechanism 13, the refrigerant sensor 16, the first shutoff valve 33, and the second shutoff valve 43 so as to be able to transmit and receive signals. The control unit 7 may be electrically connected to various sensors (not shown) provided in the utilization unit 1 and the heat source unit 2. The control unit 7 may be able to communicate with a remote control (not shown) operated by a user of the refrigeration cycle apparatus 100.

[0062] The control unit 7 is realized by a computer. The control unit 7 includes a control arithmetic device and a storage device (both not shown). The control arithmetic device is a processor such as a CPU or GPU. The control arithmetic device reads a program stored in the storage device and performs predetermined image processing and arithmetic processing according to the program. Furthermore, the control arithmetic device writes the calculation results to the storage device and reads information stored in the storage device according to the program.

[0063] (3) Overall operation (3-1) Air conditioning operation During air conditioning operation, the control unit 7 controls the operations of various devices constituting the refrigeration cycle apparatus 100 as described below.

[0064] (3-1-1) Cooling operation When the start of cooling operation is instructed through a remote control or the like, the control unit 7 controls the operation of the four-way switching mechanism 22 to switch the state of the refrigerant circuit 8 to a state in which the heat source heat exchanger 23 functions as a radiator (condenser) of the refrigerant and the utilization heat exchanger 11 functions as an evaporator of the refrigerant. Specifically, the control unit 7 controls the operation of the four-way switching mechanism 22 to communicate the suction pipe P1 connected to the suction side of the compressor 21 with the second gas refrigerant pipe P5 connecting the four-way switching mechanism 22 and the gas side stop valve 26. The control unit 7 also controls the operation of the four-way switching mechanism 22 to communicate the discharge pipe P2 connected to the discharge side of the compressor 21 with the first gas refrigerant pipe P3 connecting the four-way switching mechanism 22 and the gas side of the heat source heat exchanger 23 (see the solid line in the four-way switching mechanism 22 in FIG. 1). During cooling operation, the control unit 7 operates the compressor 21, the heat source fan 27, and the utilization fan 30. During cooling operation, the control unit 7 adjusts the rotation speeds of the compressor 21, the heat source fan 27 and the utilization fan 30, and the openings of the heat source expansion mechanism 24 and the utilization expansion mechanism 13 based on the measured values ​​of various sensors.

[0065] When the control unit 7 controls the operation of various devices of the refrigeration cycle device 100 in this manner, the low-pressure gas refrigerant of the refrigeration cycle is sucked into the compressor 21 and compressed to the high pressure of the refrigeration cycle, and then discharged from the compressor 21. The high-pressure gas refrigerant discharged from the compressor 21 is sent to the heat source heat exchanger 23 through the four-way switching mechanism 22. The high-pressure gas refrigerant sent to the heat source heat exchanger 23 dissipates heat by exchanging heat with air as a cooling source supplied by the heat source fan 27 in the heat source heat exchanger 23, which functions as a refrigerant radiator, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has dissipated heat in the heat source heat exchanger 23 is sent to the heat source expansion mechanism 24 through the liquid refrigerant pipe P4. In the heat source expansion mechanism 24, the high-pressure liquid refrigerant is decompressed and becomes a low-pressure refrigerant in a gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant decompressed by the heat source expansion mechanism 24 is sent to the utilization expansion mechanism 13 of the utilization unit 1 through the liquid refrigerant pipe P4, the liquid side shutoff valve 25, the liquid refrigerant connection pipe 5, and the second shutoff valve unit 4. The low-pressure gas-liquid two-phase refrigerant is further decompressed by the utilization expansion mechanism 13 and sent to the utilization heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the utilization heat exchanger 11 evaporates by heat exchange with air supplied by the utilization fan 30 in the utilization heat exchanger 11, which functions as a refrigerant evaporator. At this time, the air cooled by heat exchange with the refrigerant is supplied to the space to be air-conditioned, and cooling of the space to be air-conditioned is performed. The low-pressure gas refrigerant evaporated in the utilization heat exchanger 11 is sucked again into the compressor 21 through the first shutoff valve unit 3, the gas refrigerant connection pipe 6, the gas side shutoff valve 26, and the four-way switching mechanism 22.

[0066] (3-1-2) Heating operation When the start of heating operation is instructed through a remote control or the like, the control unit 7 controls the operation of the four-way switching mechanism 22 to switch the state of the refrigerant circuit 8 to a state in which the heat source heat exchanger 23 functions as an evaporator of the refrigerant and the utilization heat exchanger 11 functions as a radiator (condenser) of the refrigerant. Specifically, the control unit 7 controls the operation of the four-way switching mechanism 22 to communicate the suction pipe P1 with the first gas refrigerant pipe 119 and the discharge pipe P2 with the second gas refrigerant pipe P5 (see the broken line in the four-way switching mechanism 22 in FIG. 1). During heating operation, the control unit 7 operates the compressor 21, the heat source fan 27, and the utilization fan 30. During heating operation, the control unit 7 adjusts the rotation speeds of the compressor 21, the heat source fan 27, and the utilization fan 30, and the openings of the heat source expansion mechanism 24 and the utilization expansion mechanism 13 based on the measured values ​​of various sensors, etc.

[0067] When the control unit 7 controls the operation of various devices of the refrigeration cycle device 100 in this manner, the low-pressure gas refrigerant of the refrigeration cycle is sucked into the compressor 21 and compressed to the high pressure of the refrigeration cycle, and then discharged from the compressor 21. The high-pressure gas refrigerant discharged from the compressor 21 is sent to the utilization heat exchanger 11 of the utilization unit 1 through the four-way switching mechanism 22, the gas side shutoff valve 26, the gas refrigerant communication pipe 6, and the first shutoff valve unit 3. In the utilization heat exchanger 11, which functions as a refrigerant radiator (condenser), the high-pressure gas refrigerant exchanges heat with air supplied by the utilization fan 30 to release heat, and becomes a high-pressure liquid refrigerant. At this time, the air heated by heat exchange with the refrigerant is supplied to the space to be air-conditioned, and the space to be air-conditioned is heated. The high-pressure liquid refrigerant that has released heat in the utilization heat exchanger 11 is decompressed by the utilization expansion mechanism 13 to become a low-pressure refrigerant in a gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant is sent to the heat source expansion mechanism 24 through the second shutoff valve unit 4, the liquid refrigerant connection pipe 5, the liquid side shutoff valve 25, and the liquid refrigerant pipe P4. The refrigerant sent to the heat source expansion mechanism 24 is depressurized by the heat source expansion mechanism 24 and further depressurized. The low-pressure gas-liquid two-phase refrigerant depressurized by the heat source expansion mechanism 24 is sent to the heat source heat exchanger 23 through the liquid refrigerant pipe P4. The low-pressure gas-liquid two-phase refrigerant sent to the heat source heat exchanger 23 evaporates by heat exchange with air as a heat source supplied by the heat source fan 27 in the heat source heat exchanger 23 functioning as a refrigerant evaporator, becoming a low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the heat source heat exchanger 23 is sucked back into the compressor 21 through the four-way switching mechanism 22.

[0068] (3-2) Operation in the event of a refrigerant leak When a refrigerant leak is detected in any of the multiple utilization units 1 (in other words, when the refrigerant sensor 16 detects refrigerant), the control unit 7 closes all shut-off valves (specifically, all of the first shut-off valves 33 and all of the second shut-off valves 43) that shut off the refrigerant flowing between the utilization unit 1 in which a refrigerant leak has been detected and the gas refrigerant connection pipe 6 or the liquid refrigerant connection pipe 5.

[0069] The control flow when a refrigerant leaks will be specifically described with reference to the flowchart of Fig. 3. This control flow starts when the refrigeration cycle apparatus 100 is started.

[0070] In step S10, the control unit 7 determines whether or not a refrigerant leak has been detected in any of the multiple utilization units 1, specifically, whether or not the refrigerant sensor 16 has detected a refrigerant. If the control unit 7 determines that a refrigerant has been detected (Yes), the process proceeds to step S11. If the control unit 7 does not determine that a refrigerant has been detected (No), the process proceeds to step S10.

[0071] In step S11, the control unit 7 closes all of the first shutoff valves 33 and all of the second shutoff valves 43 of the utilization units 1 in which refrigerant has been detected, and ends the control flow.

[0072] For example, when the refrigerant sensor 16a of the utilization unit 1a detects a refrigerant leak, the control unit 7 closes all of the two first shutoff valves 33a and the two second shutoff valves 43b.

[0073] (4) Features (4-1) The refrigeration cycle apparatus 100 includes a utilization unit 1, a heat source unit 2, a gas refrigerant communication pipe 6, and a first shutoff valve unit 3.

[0074] The utilization unit 1 has a utilization heat exchanger 11. The heat source unit 2 has a compressor 21 and a heat source heat exchanger 23. The gas refrigerant communication pipe 6 is provided between the compressor 21 and the utilization heat exchanger 11. The first shutoff valve unit 3 is provided between the gas refrigerant communication pipe 6 and the utilization unit 1, and shuts off the refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization unit 1.

[0075] The first shut-off valve unit 3 has a plurality of first branch pipes 31 through which the refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization units 1 flows in parallel with each other, and a shut-off valve 33 provided in each of the plurality of first branch pipes 31.

[0076] In the refrigeration cycle apparatus 100, the refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization units 1 is diverted to a plurality of first diverter pipes 31, so the amount of refrigerant passing through each shutoff valve 33 is less than when the refrigerant is not diverted. This allows the shutoff valves 33 to be designed to be small, suppressing an increase in manufacturing costs associated with an increase in the size of each shutoff valve 33. Therefore, the refrigeration cycle apparatus 100 can suppress refrigerant leakage in the utilization units 1 while suppressing an increase in manufacturing costs.

[0077] (4-2) The refrigeration cycle apparatus 100 further includes a liquid refrigerant communication pipe 5 and a second shutoff valve unit 4. The liquid refrigerant communication pipe 5 is provided between the utilization heat exchanger 11 and the heat source heat exchanger 23. The second shutoff valve unit 4 is provided between the liquid refrigerant communication pipe 5 and the utilization unit 1, and shuts off the refrigerant flowing between the liquid refrigerant communication pipe 5 and the utilization unit 1.

[0078] The second shut-off valve unit 4 has a plurality of second branch pipes 41 through which the refrigerant flowing between the liquid refrigerant communication pipe 5 and the utilization unit 1 flows in parallel with each other, and a plurality of shut-off valves 43 provided in each of the second branch pipes 41.

[0079] The refrigeration cycle apparatus 100 also has the shutoff valve 43 between the liquid refrigerant communication pipe 5 and the utilization unit 1, so that refrigerant leakage in the utilization unit 1 can be effectively suppressed while suppressing an increase in manufacturing costs.

[0080] (4-3) The refrigeration cycle apparatus 100 further includes a control unit 7 that controls the shutoff valves 33 and 43 .

[0081] When a refrigerant leak is detected in the utilization unit 1, the control unit 7 closes all of the shut-off valves 33, 43 that shut off the refrigerant flowing between the utilization unit 1 in which the refrigerant leak was detected and the gas refrigerant connection pipe 6 or the liquid refrigerant connection pipe 5.

[0082] The refrigeration cycle apparatus 100 can suppress refrigerant leakage in the utilization unit 1 in the event that refrigerant leakage occurs.

[0083] (4-4) The rated capacity of the utilization unit 1 is 10 horsepower or more.

[0084] In general, the larger the rated capacity of the utilization unit 1, the larger the amount of refrigerant flowing between the utilization unit 1 and the liquid refrigerant connection pipe 5 or the gas refrigerant connection pipe 6, and the bore of the shutoff valve used is designed to be larger. As a result, the manufacturing cost of the shutoff valve used in the utilization unit 1 with a large rated capacity tends to be high. The refrigeration cycle apparatus 100 can suppress high manufacturing costs even if the utilization unit 1 has a large rated capacity of 10 horsepower or more.

[0085] (4-5) The first shutoff valve 33 and the second shutoff valve 43 are needle valves.

[0086] The larger the aperture of a needle valve, the more difficult it tends to be to suppress the amount of leakage when the valve is closed. Although the amount of leakage can be suppressed by improving the manufacturing precision of the valve, improving precision leads to an increase in manufacturing costs. Since the refrigeration cycle apparatus 100 can suppress an increase in the aperture of the shutoff valves 33, 43, even when a needle valve is used, it is possible to suppress refrigerant leakage from the utilization unit 1 while suppressing an increase in manufacturing costs.

[0087] (5) Variations (5-1) Variation 1A The refrigeration cycle apparatus 100 does not necessarily have to include the second shutoff valve unit 4. In other words, the refrigeration cycle apparatus 100 may include only the first shutoff valve unit 3.

[0088] (5-2) Variation 1B The control unit 7 may have a utilization unit control unit 17, a heat source unit control unit 28, and a shutoff valve control unit .

[0089] 4, the utilization unit control unit 17 controls the utilization fan 12 and the utilization expansion mechanism 13. The utilization unit control unit 17 is electrically connected to the utilization fan 12, the utilization expansion mechanism 13, the refrigerant sensor 16, and the heat source unit control unit 28 so as to be able to transmit and receive signals.

[0090] The heat source unit control unit 28 controls the compressor 21, the four-way switching mechanism 22, the heat-source expansion mechanism 24, and the heat-source fan 27. The heat source unit control unit 28 is electrically connected to the compressor 21, the four-way switching mechanism 22, the heat-source expansion mechanism 24, the heat-source fan 27, and the utilization unit control unit 17 so as to be able to send and receive signals.

[0091] The shutoff valve control unit 34 controls the first shutoff valve 33 and the second shutoff valve 43. The shutoff valve control unit 34 is electrically connected to the first shutoff valve 33, the second shutoff valve 43, and the heat source unit control unit 28 so as to be able to send and receive signals.

[0092] In the refrigeration cycle apparatus 100 according to the modification 1B, when the refrigerant sensor 16 of the utilization unit 1 detects a refrigerant, the utilization unit control unit 17 transmits a first signal to the heat source unit control unit 28. When the heat source unit control unit 28 receives the first signal transmitted by the utilization unit control unit 17, it transmits a second signal to the shutoff valve control unit 34. When the shutoff valve control unit 34 receives the second signal transmitted by the heat source unit control unit 28, it closes all of the first shutoff valves 33 and all of the second shutoff valves 43 which shut off the refrigerant flowing between the utilization unit in which a refrigerant leak was detected, the utilization unit 1 in which a refrigerant leak was detected, and the gas refrigerant communication pipe 6 or the liquid refrigerant communication pipe 5.

[0093] In the refrigeration cycle apparatus 100 of variant example 1B, the shutoff valve control unit 34 closes all of the corresponding first shutoff valves 33 and all of the second shutoff valves 43 based on a signal sent from the utilization unit control unit 17 itself when a refrigerant leak is detected, thereby preventing the first shutoff valves 33 and the second shutoff valves 43 corresponding to a utilization unit 1 where no refrigerant leak is occurring from being erroneously closed.

[0094] Moreover, the refrigeration cycle apparatus 100 according to Modification 1B does not require a new communication line between the utilization unit control unit 17 and the shutoff valve control unit 34. Furthermore, according to the refrigeration cycle apparatus 100 according to Modification 1B, the heat source unit control unit 28 can comprehensively control the utilization units 1, the first shutoff valve unit 3, and the second shutoff valve unit 4.

[0095] (5-3) Variation 1C The utilization unit control section 17 may further be electrically connected to the shutoff valve control section 34 so as to be able to send and receive signals thereto.

[0096] In the refrigeration cycle apparatus 100 according to modification 1C, when the refrigerant sensor 16 of the utilization unit 1 detects a refrigerant, the utilization unit control unit 17 transmits a third signal to the shutoff valve control unit 34. When the shutoff valve control unit 34 receives the third signal transmitted by the heat source unit control unit 28, it closes all of the first shutoff valves 33 and all of the second shutoff valves 43 which shut off the refrigerant flowing between the utilization unit 1 in which a refrigerant leak has been detected and the gas refrigerant communication pipe 6 or the liquid refrigerant communication pipe 5.

[0097] In the refrigeration cycle apparatus 100 of variant example 1C, the shutoff valve control unit 34 closes all of the corresponding first shutoff valves 33 and all of the second shutoff valves 43 based on a signal sent from the utilization unit control unit 17 itself when a refrigerant leak is detected, thereby preventing the first shutoff valves 33 and the second shutoff valves 43 corresponding to a utilization unit 1 where no refrigerant leak is occurring from being erroneously closed.

[0098] Furthermore, in the refrigeration cycle apparatus 100 according to Modification 1C, a signal is sent directly from the utilization unit control unit 17 to the corresponding shutoff valve control unit 34, so that refrigerant leakage can be quickly suppressed.

[0099] (5-4) Variation 1D When the control unit 7 detects an abnormality in any of the multiple first shut-off valves 33 and the multiple second shut-off valves 43, it may close the first shut-off valves 33 and the second shut-off valves 43 corresponding to all remaining utilization units 1, and then stop operation of any of the utilization units 1 and the heat source units 2.

[0100] Here, the abnormality in either the first shut-off valve 33 or the multiple second shut-off valves 43 is, but is not limited to, a communication abnormality or a broken line detected by the absence of a reply (ack) to a signal sent by the control unit 7.

[0101] The refrigeration cycle apparatus 100 according to the modification 1D can prevent the first shutoff valve 33 or the second shutoff valve 43 from failing to operate when refrigerant leaks.

[0102] (5-4) Variation 1E In the refrigeration cycle apparatus 100, the first shutoff valve unit 3 and the second shutoff valve unit 4 are disposed outside the utilization unit 1, but there is no limitation on the installation positions of the first shutoff valve unit 3 and the second shutoff valve unit 4. At least one of the first shutoff valve unit 3 and the second shutoff valve unit 4 may be disposed inside the utilization unit 1 (more specifically, inside the casing (not shown) of the utilization unit 1).

[0103] (5-4) Variation 1F In the refrigeration cycle apparatus 100, the first shutoff valve unit 3 and the second shutoff valve unit 4 are provided for all of the multiple utilization units 1, but the first shutoff valve unit 3 and the second shutoff valve unit 4 may not be provided for some of the multiple utilization units 1. For example, some of the multiple utilization units 1 may not be provided with the first shutoff valve unit 3 and the second shutoff valve unit 4, and instead, one shutoff valve may be provided directly in each of the liquid refrigerant pipe 14 and the gas refrigerant pipe 15.

[0104] (5-5) Variation 1G The rated capacity of the utilization unit 1 may be less than 10 horsepower. In this case, for a utilization unit 1 having a rated capacity of less than 10 horsepower, either the first shutoff valve unit 3 or the second shutoff valve unit 4 may not be provided.

[0105] <Second embodiment> (1) Overall structure Next, a refrigeration cycle apparatus 100a according to a second embodiment will be described. In the following, differences between the refrigeration cycle apparatus 100 and the refrigeration cycle apparatus 100a will be mainly described, and descriptions of the same or corresponding features and well-known techniques may be omitted.

[0106] The refrigeration cycle apparatus 100a can perform simultaneous heating and cooling operation in which some of the multiple utilization units 1 perform heating operation and the remaining utilization units 1 perform cooling operation. The refrigeration cycle apparatus 100a is equipped with a high-pressure gas refrigerant communication pipe 6a and a low-pressure gas refrigerant communication pipe 6b as the gas refrigerant communication pipe 6. The refrigeration cycle apparatus 100a is equipped with a plurality of first shutoff valve units 9 instead of the plurality of first shutoff valve units 3 and the plurality of second shutoff valve units 4.

[0107] (2) Detailed configuration The first shutoff valve unit 9 has two first branch pipes 91 and two first shutoff valves 93 .

[0108] One side of the first branch pipe 91 connects the high-pressure gas refrigerant communication pipe 6a and the gas side of the utilization heat exchanger 11 of the utilization unit 1. The other side of the first branch pipe 91 connects the low-pressure gas refrigerant communication pipe 6b and the gas side of the utilization heat exchanger 11 of the utilization unit 1.

[0109] The first shutoff valve unit 9 of the refrigeration cycle apparatus 100a has two first branch pipes 91 which are pipes through which the refrigerant flowing between the high-pressure gas refrigerant communication pipe 6a and the low-pressure gas refrigerant communication pipe 6b and the utilization unit 1 flows in parallel with each other.

[0110] The first shutoff valve 93 is provided in the first branch pipe 91 .

[0111] The liquid refrigerant communication pipe 5 and the liquid side of the utilization heat exchanger 11 of the utilization unit 1 are connected by a pipe 92d.

[0112] 5 shows an example in which the refrigeration cycle apparatus 100a includes two utilization units 1. In order to distinguish between the two utilization units 1, the respective utilization units 1 and the devices included in the utilization units 1 are indicated with suffixes c and d.

[0113] The number of utilization units 1 is not limited to two, but may be three or more.

[0114] (3) Overall operation (operation in the event of a refrigerant leak) As in the refrigeration cycle apparatus 100, in the refrigeration cycle apparatus 100a, when a refrigerant leak is detected in any of the utilization units 1 (when the refrigerant sensor 16 detects a refrigerant), the control unit 7 closes all of the first shutoff valves 93 that shut off the refrigerant flowing between the utilization unit 1 in which the refrigerant leak was detected and between the utilization unit 1 and each of the high-pressure gas refrigerant communication pipe 6a and the low-pressure gas refrigerant communication pipe 6b.

[0115] (3) Variation 2 The refrigeration cycle apparatus 100a may further include a second shutoff valve unit 4 provided on a pipe 92d that connects the liquid refrigerant communication pipe 5 and the utilization unit 1.

[0116] <Conclusion> Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0117] 1: Unit of use 2: Heat source unit 3, 9: First shutoff valve unit 4: Second shutoff valve unit 5: Liquid refrigerant connection pipe 6: Gas refrigerant connection pipe 7: Control section 11: Use heat exchanger 17: Utilization unit control section 21: Compressor 23:Heat source heat exchanger 28: Heat source unit control section 31, 91: 1st branch pipe 33, 93: First shutoff valve (shutoff valve) 34:Shutoff valve control section 41:Second branch pipe 43: Second shutoff valve (shutoff valve) 100, 100a: Refrigeration cycle device [Prior art documents] [Patent documents]

[0118] [Patent Document 1] Patent No. 2020-030043

Claims

1. A utilization unit (1) having a utilization heat exchanger (11); A heat source unit (2) having a compressor (21) and a heat source heat exchanger (23); A gas refrigerant communication pipe (6) provided between the compressor and the heat utilization exchanger; a first shutoff valve unit (3) provided between the gas refrigerant communication pipe and the utilization unit, for shutting off the refrigerant flowing between the gas refrigerant communication pipe and the utilization unit; Equipped with The first shutoff valve unit is a plurality of first branch pipes (31) through which the refrigerant flowing between the gas refrigerant communication pipe and the utilization units flows in parallel with each other; a shutoff valve (33) provided in each of the plurality of first branch pipes; having A refrigeration cycle device (100).

2. A liquid refrigerant communication pipe (5) provided between the utilization heat exchanger and the heat source heat exchanger; a second shutoff valve unit (4) provided between the liquid refrigerant communication pipe and the utilization unit, for shutting off the refrigerant flowing between the liquid refrigerant communication pipe and the utilization unit; Further equipped with The second shutoff valve unit is a plurality of second branch pipes (41) through which the refrigerant flowing between the liquid refrigerant communication pipe and the utilization units flows in parallel with each other; A plurality of shutoff valves (43) provided in each of the second branch pipes; having The refrigeration cycle device according to claim 1.

3. A control unit (7) for controlling the shutoff valve is further provided. The control unit is when leakage of the refrigerant is detected in the utilization unit, all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which leakage of the refrigerant is detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe are closed. The refrigeration cycle device according to claim 2.

4. The control unit is A utilization unit control unit (17) provided in the utilization unit; A heat source unit control unit (28) provided in the heat source unit; A shutoff valve control unit (34) for controlling the shutoff valve; having The utilization unit control unit When a leakage of the refrigerant is detected in the utilization unit, a first signal is transmitted to the heat source unit control unit; The heat source unit control unit is transmitting a second signal to the shutoff valve control unit upon receiving the first signal; The shutoff valve control unit is when the second signal is received, all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leakage has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe are closed. The refrigeration cycle device according to claim 3.

5. The control unit is A utilization unit control unit (17) provided in the utilization unit; A shutoff valve control unit (34) for controlling the shutoff valve; having The utilization unit control unit When a leakage of the refrigerant is detected in the utilization unit, a third signal is transmitted to the shutoff valve control unit; The shutoff valve control unit is when the third signal is received, all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leakage has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe are closed. The refrigeration cycle device according to claim 3.

6. A control unit (7) for controlling the shutoff valve is further provided. The control unit is when an abnormality is detected in any one of the plurality of shutoff valves, all the remaining shutoff valves are closed, and then the operation of any one of the utilization units and the heat source unit is stopped. The refrigeration cycle apparatus according to claim 1 or 2.

7. The rated capacity of the utilization unit is: 10 horsepower or more The refrigeration cycle apparatus according to claim 1 or 2.

8. The shutoff valve is A needle valve, The refrigeration cycle apparatus according to claim 1 or 2.

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