Refrigeration cycle device

Abstract

Provided is a refrigeration cycle device that achieves a reduction in refrigerant leakage in a utilization unit while suppressing an increase in manufacturing cost. A refrigeration cycle device (100) comprises a utilization unit (1), a heat source unit (2), a gas-refrigerant connection pipe (6), and a first shutoff valve unit (3). 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 connection 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 connection pipe (6) and the utilization unit (1), and shuts off refrigerant that flows between the gas-refrigerant connection pipe (6) and the utilization unit (1). The first shutoff valve unit (3) has a plurality of first flow division pipes (31) that allow the refrigerant that flows between the gas-refrigerant connection pipe (6) and the utilization unit (1) to flow in parallel to each other, and a shutoff valve (33) provided for each of the plurality of first flow division pipes (31).

Description

Refrigeration cycle equipment

[0001] This relates to a refrigeration cycle device.

[0002] The air conditioning system disclosed in Patent Document 1 (JP 2020-030043 A) has a shutoff valve provided between the indoor unit and the liquid piping and a shutoff valve provided 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 stop the flow of refrigerant to the indoor unit, thereby suppressing further refrigerant leakage in the air-conditioned space.

[0003] In the air conditioning system of Patent Document 1, the refrigerant is shut off using only one shutoff valve for each of the liquid and gas pipes. Therefore, if 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 refrigerant.

[0004] It may be possible to use a large-diameter shutoff valve to shut off the flow of refrigerant in a large-capacity indoor unit with a single 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.

[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 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 the refrigerant flowing between the gas refrigerant communication pipe and the utilization units flows in parallel with each other, and a shutoff valve provided in each of the plurality of first branch pipes.

[0009] In the refrigeration cycle apparatus, the refrigerant flowing between the gas refrigerant communication pipe and the user 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 compact, suppressing the increase in manufacturing costs that would otherwise be associated with larger shutoff valves. Therefore, the refrigeration cycle apparatus can suppress refrigerant leakage in the user units while suppressing the 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 units and shuts off refrigerant flowing between the liquid refrigerant communication pipe and the utilization units.

[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 with each other, and a plurality of shutoff valves provided in each of the second branch pipes.

[0012] This refrigeration cycle device also has a shutoff valve between the liquid refrigerant communication pipe and the utilization unit, so that refrigerant leakage in the utilization unit can be more effectively suppressed 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 that controls 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 has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe.

[0014] In the event that a refrigerant leak occurs, the refrigeration cycle device 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 sends a first signal to the heat source unit control unit. When the heat source unit control unit receives the first signal, it sends 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 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 user unit control unit itself when a refrigerant leak is detected, thereby preventing the shut-off valve corresponding to a user unit where a refrigerant leak is not occurring from being closed by mistake.

[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. Upon receiving the third signal, the shutoff valve 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.

[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.As a result, 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 that controls the shutoff valves. When the control unit detects an abnormality in any of the plurality of shutoff valves, it closes all of the remaining shutoff valves and then stops operation of any of the utilization units and the heat source units.

[0024] According to the present refrigeration cycle device, it is possible to prevent the shutoff valve from failing to operate in the event of 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 device 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, wherein the shutoff valve is a needle valve.

[0028] This refrigeration cycle device can prevent the diameter of the shutoff valve from increasing, so even if a needle valve is used for the shutoff valve, it can prevent refrigerant leakage in the utilization unit while suppressing an increase in manufacturing costs.

[0029] It is a schematic configuration diagram of a refrigeration cycle apparatus 100 according to a first embodiment. It is a block diagram of a control unit 7 of the refrigeration cycle apparatus 100 according to the first embodiment. It is a flowchart showing a control flow at the time of refrigerant leakage. It is a block diagram of a control unit 7 of the refrigeration cycle apparatus 100 according to a modified example A. It is a schematic configuration diagram of a refrigeration cycle apparatus 100a according to a second embodiment.

[0030] First Embodiment (1) Overall Configuration The refrigeration cycle apparatus 100 performs air conditioning operations (specifically, cooling operations and heating operations) in a space to be air-conditioned by using 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 also be used in other refrigerant cycle apparatuses, such as a refrigerator, a freezer, a water heater, or a floor heating apparatus.

[0031] The refrigeration cycle apparatus 100 mainly has two user 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 user units 1 and the heat source units 2. In the refrigeration cycle apparatus 100, a refrigerant circuit 8 is formed by connecting the user units 1 and the heat source units 2 via the liquid refrigerant connection pipe 5 and the gas refrigerant connection pipe 6. In other words, the liquid refrigerant connection pipe 5 is provided between the user heat exchanger 11 and the heat source heat exchanger 23 (both described below). The gas refrigerant connection pipe 6 is provided between the compressor 21 (described below) and the user heat exchanger 11.

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

[0033] (2) Detailed Configuration (2-1) User Unit 1 As shown in Fig. 1, the user unit 1 mainly includes a user heat exchanger 11, a user fan 12, a user expansion mechanism 13, a liquid refrigerant pipe 14, a gas refrigerant pipe 15, and a refrigerant sensor 16. The user unit 1 has a rated capacity of 10 horsepower or more.

[0034] Hereinafter, when it is necessary to distinguish between the two usage units 1, the usage unit 1 installed in room A will be referred to as usage unit 1a, and the usage unit 1 installed in room B will be referred to as usage unit 1b. Similarly, the devices included in usage unit 1a may be indicated by adding the suffix a to the reference symbol, and the devices included in usage 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) Utilization 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 communication pipe 5 via a liquid refrigerant pipe 14, and the other end is connected to the gas refrigerant communication pipe 6 via a gas refrigerant pipe 15.

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

[0038] (2-1-3) Utilization Expansion Mechanism 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 air-conditioned space where the utilization unit 1 is installed. In other words, the refrigerant sensor 16 detects refrigerant leakage in the air-conditioned space.

[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 refrigerant pipes connecting the various devices that make up the refrigerant circuit 8, including 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. The suction pipe P1 connects the four-way switching mechanism 22 to the suction side of the compressor 21. The discharge pipe P2 connects the discharge side of the compressor 21 to the four-way switching mechanism 22. The first gas refrigerant pipe P3 connects the four-way switching mechanism 22 to 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 to a liquid-side shut-off 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 to a gas-side shut-off valve 26.

[0042] (2-2-1) Compressor 21 The compressor 21 draws low-pressure refrigerant in the refrigeration cycle through the suction pipe P1, compresses the refrigerant using a compression mechanism (not shown), and discharges the refrigerant to the 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 cooling operation and heating operation. When the refrigerant circuit 8 is in cooling operation, the heat source heat exchanger 23 functions as a refrigerant radiator (condenser), and the utilization heat exchanger 11 functions as a refrigerant evaporator. When the refrigerant circuit 8 is in heating operation, 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 the 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 Figure 1).When the four-way switching mechanism 22 sets the refrigerant circuit 8 to the 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 Figure 1).

[0045] (2-2-3) Heat Source Heat Exchanger 23 The heat source heat exchanger 23 exchanges heat between the refrigerant flowing inside and the 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 Shut-Off Valve 25 and Gas Side Shut-Off 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 communication 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 communication 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 external 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 to each other. The refrigerant flowing between the gas refrigerant communication pipe 6 and the utilization units 1 is branched and flows 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 shut-off 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 shut-off valves 33 are closed. In other words, the flow of refrigerant between the utilization units 1 and the gas refrigerant communication pipes 6 is shut off when all of the first shut-off valves 33 are closed. If the refrigerant sensor 16 does not detect a refrigerant leak, the first shut-off valves 33 generally remain open. In this embodiment, the first shut-off valve unit 3 has two first shut-off valves 33.

[0053] Although not limited thereto, the first shutoff valve 33 is a needle valve. 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 devices included in the first shutoff valve unit 3a will be indicated by adding the suffix a to their reference symbols, and the devices included in the first shutoff valve unit 3b will be indicated by adding the suffix b to their reference symbols.

[0055] (2-4) Second shutoff valve unit 4 The second shutoff valve unit 4 is provided between the liquid refrigerant communication pipe 5 and the user unit 1, and shuts off the refrigerant flowing between the liquid refrigerant communication pipe 5 and the user unit 1. The second shutoff valve unit 4 is disposed outside the user 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 plurality of second branch pipes 41 are pipes through which the refrigerant flowing between the liquid refrigerant communication pipe 5 and the utilization units 1 flows in parallel with each other. The refrigerant flowing between the liquid refrigerant communication pipe 5 and the utilization units 1 is branched and flows through the plurality of second branch pipes 41. In this embodiment, the second shutoff valve unit 4 has two second branch pipes 41.

[0058] A second shut-off 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 shut-off 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 shut-off valves 43 are closed. If the refrigerant sensor 16 does not detect a refrigerant leak, the second shut-off valves 43 generally remain open. In this embodiment, the second shut-off valve unit 4 has two second shut-off valves 43.

[0059] Although not limited thereto, the second shutoff valve 43 is a needle valve. The number of second branch pipes 41 and 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 devices included in the second shutoff valve unit 4a will be indicated by adding the suffix a to their reference symbols, and the devices included in the second shutoff valve unit 4b will be indicated by adding the suffix b to their reference symbols.

[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 shut-off valve 33, and the second shut-off valve 43 so as to be able to send 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 and arithmetic unit and a storage device (both not shown). The control and arithmetic unit is a processor such as a CPU or GPU. The control and arithmetic unit reads a program stored in the storage device and performs predetermined image processing and arithmetic processing in accordance with the program. Furthermore, the control and arithmetic unit writes the results of calculations to the storage device and reads information stored in the storage device in accordance with 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 an instruction to start cooling operation is received via 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 refrigerant radiator (condenser) and the utilization heat exchanger 11 functions as a refrigerant evaporator. Specifically, the control unit 7 controls the operation of the four-way switching mechanism 22 to connect 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 shut-off valve 26. The control unit 7 also controls the operation of the four-way switching mechanism 22 to connect 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. Furthermore, 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, as well as the opening degrees of the heat source expansion mechanism 24 and the utilization expansion mechanism 13, based on the measurement values ​​of various sensors, etc.

[0065] When the control unit 7 controls the operation of the various devices of the refrigeration cycle apparatus 100 in this manner, the low-pressure gas refrigerant of the refrigeration cycle is drawn into the compressor 21, 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 via the four-way switching mechanism 22. The high-pressure gas refrigerant sent to the heat-source heat exchanger 23 dissipates heat in the heat-source heat exchanger 23, which functions as a refrigerant radiator, by exchanging heat with air serving as a cooling source supplied by the heat-source fan 27, thereby becoming 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 to become 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 air-conditioned space, where the air is cooled. The low-pressure gas refrigerant evaporated in the utilization heat exchanger 11 is sucked back 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 a command to start heating operation is received via 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 refrigerant evaporator and the utilization heat exchanger 11 functions as a refrigerant radiator (condenser). Specifically, the control unit 7 controls the operation of the four-way switching mechanism 22 to connect the suction pipe P1 to the first gas refrigerant pipe 119 and the discharge pipe P2 to the second gas refrigerant pipe P5 (see the dashed lines within 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. Furthermore, 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, as well as the opening degrees of the heat-source expansion mechanism 24 and the utilization expansion mechanism 13, based on measurements from various sensors.

[0067] When the control unit 7 controls the operation of the various devices of the refrigeration cycle apparatus 100 in this manner, the low-pressure gas refrigerant of the refrigeration cycle is drawn into the compressor 21, 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 via the four-way switching mechanism 22, the gas-side shut-off valve 26, the gas refrigerant communication pipe 6, and the first shut-off 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, releasing heat and becoming 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, heating the space to be air-conditioned. The high-pressure liquid refrigerant that has released heat in the utilization heat exchanger 11 is decompressed by the utilization expansion mechanism 13 and becomes 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 via the second shutoff valve unit 4, the liquid refrigerant communication 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 via the liquid refrigerant pipe P4. The low-pressure gas-liquid two-phase refrigerant sent to the heat source heat exchanger 23 evaporates through heat exchange with air serving as a heat source, supplied by the heat source fan 27, in the heat source heat exchanger 23, which functions as a refrigerant evaporator, and becomes low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the heat source heat exchanger 23 is sucked back into the compressor 21 via 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 user units 1 (in other words, when the refrigerant sensor 16 detects refrigerant), the control unit 7 closes all shut-off valves (specifically, all first shut-off valves 33 and all second shut-off valves 43) that shut off the refrigerant flowing between the user unit 1 in which the refrigerant leak has been detected and the gas refrigerant communication pipe 6 or the liquid refrigerant communication 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 a refrigerant leak has been detected in any of the multiple utilization units 1, specifically, whether 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 user 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 unit 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 compact, suppressing an increase in manufacturing costs that would otherwise be 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 units 1, and shuts off the refrigerant flowing between the liquid refrigerant communication pipe 5 and the utilization units 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 device 100 also has a 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 a user unit 1, the control unit 7 closes all shut-off valves 33, 43 that shut off the refrigerant flowing between the user unit 1 in which the refrigerant leak was detected and the gas refrigerant communication pipe 6 or the liquid refrigerant communication pipe 5.

[0082] In the event that a refrigerant leak occurs, the refrigeration cycle apparatus 100 can suppress the refrigerant leak from the utilization unit 1.

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

[0084] Generally, 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 communication pipe 5 or the gas refrigerant communication pipe 6, and the diameter of the shutoff valve used is designed to be larger. As a result, the manufacturing costs of a shutoff valve used in a utilization unit 1 with a large rated capacity tend to be high. The refrigeration cycle apparatus 100 can suppress high manufacturing costs even if it has a utilization unit 1 with 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 diameter of a needle valve, the more difficult it tends to be to suppress the amount of leakage when the valve is closed. Although this leakage can be suppressed by improving the manufacturing precision of the valve, improving precision increases manufacturing costs. Because the refrigeration cycle apparatus 100 can suppress an increase in the diameter of the shutoff valves 33, 43, even when a needle valve is used, it is possible to suppress refrigerant leakage in the utilization unit 1 while suppressing an increase in manufacturing costs.

[0087] (5) Modifications (5-1) Modification 1A The refrigeration cycle apparatus 100 does not 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) Modification 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 34.

[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 send and receive signals thereto.

[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 Modification 1B, when the refrigerant sensor 16 of a user unit 1 detects a refrigerant, the user unit control unit 17 sends a first signal to the heat source unit control unit 28. When the heat source unit control unit 28 receives the first signal sent by the user unit control unit 17, it sends a second signal to the shutoff valve control unit 34. When the shutoff valve control unit 34 receives the second signal sent 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 that shut off the refrigerant flowing between the user unit in which a refrigerant leak was detected, the user 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 device 100 relating to variant example 1B, the shut-off valve control unit 34 closes all corresponding first shut-off valves 33 and all corresponding second shut-off 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 shut-off valves 33 and second shut-off valves 43 corresponding to utilization units 1 where no refrigerant leak is occurring from being erroneously closed.

[0094] Furthermore, the refrigeration cycle apparatus 100 according to Modification 1B does not require the provision of 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) Modification 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 user unit 1 detects a refrigerant, the user unit control unit 17 sends a third signal to the shutoff valve control unit 34. When the shutoff valve control unit 34 receives the third signal sent 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 that shut off the refrigerant flowing between the user 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 device 100 relating to variant example 1C, the shut-off valve control unit 34 closes all corresponding first shut-off valves 33 and all corresponding second shut-off valves 43 based on a signal sent from the user unit control unit 17 itself when a refrigerant leak is detected, thereby preventing the first shut-off valves 33 and second shut-off valves 43 corresponding to the user unit 1 where no refrigerant leak is occurring from being erroneously closed.

[0098] Furthermore, the refrigeration cycle apparatus 100 according to Modification 1C transmits a signal directly from the utilization unit control unit 17 to the corresponding shutoff valve control unit 34, and therefore, 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 multiple second shut-off valves 43, it may close the first shut-off valves 33 and second shut-off valves 43 corresponding to all remaining utilization units 1, and then stop operation of either the utilization unit 1 or the heat source unit 2.

[0100] Here, the abnormality of either the first shut-off valve 33 or the plurality of second shut-off valves 43 is, but is not limited to, a communication abnormality or a broken wire 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 Modification 1D can prevent the first shutoff valve 33 or the second shutoff valve 43 from failing to operate in the event of refrigerant leakage.

[0102] (5-5) Modification 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 are no limitations 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] (5-6) Modification 1F In the refrigeration cycle apparatus 100, the first shut-off valve unit 3 and the second shut-off valve unit 4 are provided for all of the multiple utilization units 1, but the first shut-off valve unit 3 and the second shut-off 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 shut-off valve unit 3 and the second shut-off valve unit 4, and instead, one shut-off valve may be provided directly in each of the liquid refrigerant pipe 14 and the gas refrigerant pipe 15.

[0104] (5-7) Modification 1G The rated capacity of the utilization unit 1 may be less than 10 horsepower. In this case, for a utilization unit 1 with 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 Configuration Next, a refrigeration cycle apparatus 100a according to a second embodiment will be described. The following description will focus on differences between the refrigeration cycle apparatus 100 and the refrigeration cycle apparatus 100a, and descriptions of identical or corresponding features and well-known techniques may be omitted.

[0106] The refrigeration cycle apparatus 100a is capable of 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 includes 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 includes 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 to 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 to 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 between the utilization unit 1 and the high-pressure gas refrigerant communication pipe 6a and the low-pressure gas refrigerant communication pipe 6b 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. 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 refrigerant leakage) As in the refrigeration cycle apparatus 100, in the refrigeration cycle apparatus 100a, when a refrigerant leakage is detected in any of the user units 1 (when the refrigerant sensor 16 detects refrigerant), the control unit 7 closes all of the first shut-off valves 93 that shut off the refrigerant flowing between the user unit 1 in which the refrigerant leakage was detected and the high-pressure gas refrigerant communication pipe 6a and the low-pressure gas refrigerant communication pipe 6b, and the user unit 1.

[0115] (4) Modification 2 The refrigeration cycle apparatus 100 a may further include a second shutoff valve unit 4 provided on the pipe 92 d that connects the liquid refrigerant communication pipe 5 and the utilization units 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 as defined in the claims.

[0117] REFRIGERATION SYSTEM 1: Utilization unit 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 unit 11: Utilization heat exchanger 17: Utilization unit control unit 21: Compressor 23: Heat source heat exchanger 28: Heat source unit control unit 31, 91: First branch pipe 33, 93: First shutoff valve (shutoff valve) 34: Shutoff valve control unit 41: Second branch pipe 43: Second shutoff valve (shutoff valve) 100, 100a: Refrigeration cycle device

[0118] Japanese Patent Application Laid-Open No. 2020-030043

Claims

1. A refrigeration cycle device (100) comprising: 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 utilization heat exchanger; and a first shutoff valve unit (3) provided between the gas refrigerant communication pipe and the utilization unit and shutting off the refrigerant flowing between the gas refrigerant communication pipe and the utilization unit, wherein the first shutoff valve unit has a plurality of first branch pipes (31) through which the refrigerant flowing between the gas refrigerant communication pipe and the utilization unit flows in parallel with each other, and a shutoff valve (33) provided in each of the plurality of first branch pipes.

2. The refrigeration cycle apparatus according to claim 1, further comprising: a liquid refrigerant connection pipe (5) provided between the utilization heat exchanger and the heat source heat exchanger; and a second shutoff valve unit (4) provided between the liquid refrigerant connection pipe and the utilization unit and shutting off the refrigerant flowing between the liquid refrigerant connection pipe and the utilization unit, wherein the second shutoff valve unit has a plurality of second branch pipes (41) through which the refrigerant flowing between the liquid refrigerant connection pipe and the utilization unit flows in parallel with each other, and a plurality of shutoff valves (43) provided in each of the second branch pipes.

3. The refrigeration cycle apparatus of claim 2, further comprising a control unit (7) for controlling the shut-off valves, wherein when a refrigerant leak is detected in the utilization unit, the control unit closes all of the shut-off valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leak has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe.

4. The refrigeration cycle apparatus of claim 3, wherein the control unit has a utilization unit control unit (17) provided in the utilization unit, a heat source unit control unit (28) provided in the heat source unit, and a shut-off valve control unit (34) that controls the shut-off valve, wherein the utilization unit control unit transmits a first signal to the heat source unit control unit when a refrigerant leak is detected in the utilization unit, and the heat source unit control unit transmits a second signal to the shut-off valve control unit when it receives the first signal, and the shut-off valve control unit closes all of the shut-off valves that shut off the refrigerant flowing between the utilization unit in which a refrigerant leak has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe when it receives the second signal.

5. The refrigeration cycle apparatus of claim 3, wherein the control unit has a utilization unit control unit (17) provided in the utilization unit and a shutoff valve control unit (34) that controls the shutoff valve, and the utilization unit control unit transmits a third signal to the shutoff valve control unit when a refrigerant leak is detected in the utilization unit, and the shutoff valve control unit closes all of the shutoff valves that shut off the refrigerant flowing between the utilization unit in which the refrigerant leak has been detected and the gas refrigerant communication pipe or the liquid refrigerant communication pipe when it receives the third signal.

6. A refrigeration cycle apparatus as described in claim 1 or 2, further comprising a control unit (7) for controlling the shut-off valves, wherein when the control unit detects an abnormality in any one of the plurality of shut-off valves, it closes all of the remaining shut-off valves and then stops operation of either the utilization unit or the heat source unit.

7. A refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the rated capacity of the utilization unit is 10 horsepower or more.

8. The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein the shutoff valve is a needle valve.

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