Refrigeration cycle device

Abstract

When a shut-off valve is arranged besides an opening adjusting valve, the structure of the refrigeration cycle device becomes complicated. A refrigeration cycle device (1) is provided with a heat source unit (30), a plurality of utilization units (20, 20a), a gas opening adjustment valve (82), and a control unit (40). The gas opening degree adjusting valve (82) is provided for the utilization unit (20). The utilization unit (20) has a refrigerant sensor (61). The refrigerant sensor (61) detects leakage of the refrigerant. The control unit (40) controls the gas opening adjustment valve (82) so as to adjust the evaporation temperature or the condensation temperature in the utilization unit (20). When the refrigerant sensor (61) detects a leakage of the refrigerant, the control unit (40) blocks the refrigerant leaked from the utilization unit (20) by fully closing the gas opening adjustment valve (82).

Description

Technical Field

[0001] This disclosure relates to a refrigeration cycle apparatus. Background Technology

[0002] As shown in Patent Document 1 (Japanese Patent Application Publication No. 2008-281304), there is a technique for controlling the opening adjustment valve provided in the utilization unit to control the evaporation temperature or condensation temperature in the utilization unit. Summary of the Invention

[0003] The technical problem that the invention aims to solve

[0004] To address the possibility of refrigerant leakage within the utilization unit, it is desirable to install a shut-off valve in the utilization unit to prevent refrigerant leakage. However, installing a shut-off valve in addition to the opening regulating valve presents a technical problem that complicates the structure of the refrigeration cycle unit.

[0005] Technical solutions adopted to solve technical problems

[0006] The first-view refrigeration cycle device includes a heat source unit, multiple utilization units, a first opening regulating valve, and a control unit. The heat source unit has a compressor. The multiple utilization units, together with the heat source unit, form a refrigerant circuit. The multiple utilization units include a first utilization unit. The first opening regulating valve is provided for the first utilization unit. The first utilization unit has a first sensor. The first sensor detects refrigerant leakage. The control unit controls the first opening regulating valve, thereby adjusting the evaporation temperature or condensation temperature in the first utilization unit. If the first sensor detects refrigerant leakage, the control unit sets the first opening regulating valve to full closure, thereby blocking refrigerant leakage from the first utilization unit.

[0007] In the refrigeration cycle apparatus of the first viewpoint, when the first sensor detects a refrigerant leak, the control unit blocks the refrigerant leaking from the first utilization unit by setting the first opening regulating valve to full closure. As a result, the refrigeration cycle apparatus uses the first opening regulating valve as a shut-off valve to block the refrigerant leaking from the first utilization unit, thereby simplifying the structure of the refrigeration cycle apparatus.

[0008] The second viewpoint's refrigeration cycle device is based on the first viewpoint's refrigeration cycle device, with a first opening regulating valve installed on the first refrigerant piping on the gas side connected to the first utilization unit. When the first sensor detects a refrigerant leak, the control unit sets the first opening regulating valve to full closure, thereby blocking refrigerant leaking from the first utilization unit through the first refrigerant piping.

[0009] The third viewpoint refrigeration cycle device is based on the first viewpoint or the second viewpoint refrigeration cycle device, in which the control unit controls the first opening regulating valve so that the evaporation temperature or condensation temperature in the first utilization unit becomes the target evaporation temperature or the target condensation temperature.

[0010] The fourth viewpoint's refrigeration cycle device is based on any of the first to third viewpoints' refrigeration cycle devices. When the first sensor detects a refrigerant leak, the control unit controls the compressor based on the pressure change of the refrigerant flowing in the refrigerant circuit caused by setting the first opening regulating valve to be fully closed.

[0011] The fourth point of view, the refrigeration cycle device, is configured as described above to prevent the refrigerant pressure flowing in other utilization units from increasing and causing damage to those units.

[0012] The refrigeration cycle device of the fifth viewpoint is based on the refrigeration cycle device of any of the first to third viewpoints. When the first sensor detects a refrigerant leak, the control unit controls the compressor based on the state of the first utilization unit.

[0013] The fifth point of view, the refrigeration cycle device, is configured as described above to prevent the refrigerant pressure flowing in other utilization units from increasing and causing damage to those units.

[0014] The refrigeration cycle device of the sixth viewpoint is based on the refrigeration cycle device of the fifth viewpoint, and the state of the first utilization unit includes the capacity of the first utilization unit or the opening degree of the first opening degree regulating valve.

[0015] The refrigeration cycle device of the seventh viewpoint is based on the refrigeration cycle device of the fifth viewpoint, wherein the first utilization unit has a second opening regulating valve inside. The state of the first utilization unit includes the opening degree of the second opening regulating valve. Attached Figure Description

[0016] Figure 1 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the first embodiment.

[0017] Figure 2 This is a control block diagram illustrating the refrigeration cycle apparatus of the first embodiment.

[0018] Figure 3 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the second embodiment. Detailed Implementation

[0019] <First Implementation>

[0020] (1) Overall structure

[0021] The refrigeration cycle unit 1 constitutes a vapor compression refrigeration cycle and performs air conditioning on the target space. In this embodiment, the refrigeration cycle unit 1 is a so-called multi-split air conditioning system for buildings. Figure 1 This is a diagram showing the refrigerant circuit 50 of the refrigeration cycle apparatus 1 according to this embodiment. Figure 1 As shown, the refrigeration cycle device 1 mainly includes a heat source unit 30, multiple utilization units 20, 20a, opening degree adjustment units 80, 80a, and a control unit 40. The heat source unit 30 and the multiple utilization units 20, 20a are connected via liquid refrigerant connecting pipes 51 and gaseous refrigerant connecting pipes 52, thereby forming a refrigerant circuit 50. The heat source unit 30, the multiple utilization units 20, 20a, and the opening degree adjustment units 80, 80a are connected in a communicative manner via communication lines (not shown). Figure 1 As an example, two utilization units 20 and 20a are described, but the number of multiple utilization units connected to the heat source unit 30 is arbitrary.

[0022] (2) Detailed structure

[0023] (2-1) Utilizing the unit

[0024] Since the structures of the utilization units 20 and 20a are basically the same, the following will describe the utilization unit 20 (the first utilization unit).

[0025] The unit 20 is installed in the object space within the building where the refrigeration circulation unit 1 is located. The unit 20 can be, for example, a ceiling-recessed unit, a ceiling-suspended unit, or a floor-standing unit. Figure 1 As shown, the utilization unit 20 mainly includes a heat exchanger 21, a fan 22, an expansion valve 23 (second opening regulating valve), a control unit 29, a refrigerant sensor 61 (first sensor), and a saturation temperature sensor 64. Furthermore, the utilization unit 20 has a liquid refrigerant piping 57, which connects to a liquid refrigerant connecting piping 55, which branches off from the liquid side of the heat exchanger 21 to the utilization unit 20. The utilization unit 20 also has a gaseous refrigerant piping 58, which connects to a gaseous refrigerant connecting piping 52, which branches off from the gas side of the heat exchanger 21 to the utilization unit 20. The liquid refrigerant piping 57 and the gaseous refrigerant piping 58 are located within the utilization unit 20.

[0026] (2-1-1) Using a heat exchanger

[0027] Heat exchange is performed between the refrigerant flowing within the heat exchanger 21 and the air in the target space. The heat exchanger 21 is, for example, a finned tube heat exchanger having multiple heat transfer fins and multiple heat transfer tubes.

[0028] (2-1-2) Using a fan

[0029] Air from the object space is supplied to the heat exchanger 21 using fan 22. Fan 22 is, for example, a centrifugal fan such as a turbo fan or a Sirocco fan. Figure 1 As shown, fan 22 is driven by fan motor 22m. The speed of fan motor 22m can be controlled by inverter.

[0030] (2-1-3) Using an expansion valve

[0031] Expansion valve 23 is a mechanism used to regulate the pressure or flow rate of refrigerant flowing in liquid refrigerant piping 57. Expansion valve 23 is installed in liquid refrigerant piping 57. Expansion valve 23 is an electrically operated valve with adjustable opening.

[0032] (2-1-4) Sensor

[0033] The refrigerant sensor 61 detects refrigerant leaks. The refrigerant sensor 61 is, for example, located near the heat exchanger 21.

[0034] The saturation temperature sensor 64 measures the temperature of the refrigerant flowing in the heat exchanger 21. During cooling operation, the saturation temperature sensor 64 measures the evaporation temperature of the refrigerant flowing in the heat exchanger 21. During heating operation, the saturation temperature sensor 64 measures the condensation temperature of the refrigerant flowing in the heat exchanger 21. The saturation temperature sensor 64 is installed in the heat exchanger 21.

[0035] (2-1-5) Utilizing the control unit

[0036] The control unit 29 is connected to the various devices in the utilization unit 20 in a communicable manner. The various devices in the utilization unit 20 include an expansion valve 23, a fan motor 22m, a refrigerant sensor 61, and a saturation temperature sensor 64.

[0037] The control unit 29 includes a control processing unit and a storage device. The control processing unit is a processor such as a CPU or GPU. The storage device is a storage medium such as RAM, ROM, or flash memory. The control processing unit reads the program stored in the storage device and performs prescribed calculations according to the program, thereby controlling the operation of the various devices in the utilization unit 20. In addition, the control processing unit can write the calculation results to the storage device according to the program, and can also read the information stored in the storage device according to the program.

[0038] The control unit 29 is configured to receive various signals sent by an operating remote control (not shown). These signals include, for example, signals indicating the start or stop of operation and signals related to various settings. Signals related to various settings include, for example, signals related to set temperature and airflow.

[0039] The control unit 29 exchanges control signals, measurement signals, and various setting-related signals with the heat source control unit 39 of the heat source unit 30 and the opening control unit 89 of the opening adjustment unit 80 via a communication line. The control unit 29, the heat source control unit 39, and the opening control unit 89 cooperate to function as the control unit 40.

[0040] (2-2) Heat source unit

[0041] The heat source unit 30 is installed on the roof or other part of the building where the refrigeration cycle unit 1 is located. For example... Figure 1 As shown, the heat source unit 30 mainly includes a compressor 31, a flow path switching valve 32, a heat source heat exchanger 33, a heat source expansion valve 34, a storage tank 35, a heat source fan 36, a liquid shut-off valve 37, a gas shut-off valve 38, a heat source control unit 39, a suction pressure sensor 68, and a discharge pressure sensor 69. Furthermore, the heat source unit 30 includes a suction pipe 54a, a discharge pipe 54b, gaseous refrigerant piping 54c and 54e, and liquid refrigerant piping 54d.

[0042] The suction pipe 54a connects to the flow path switching valve 32 and the suction side of the compressor 31. A storage tank 35 is installed in the suction pipe 54a. The discharge pipe 54b connects to the discharge side of the compressor 31 and the flow path switching valve 32. The gaseous refrigerant pipe 54c connects to the flow path switching valve 32 and the gas side of the heat source heat exchanger 33. The liquid refrigerant pipe 54d connects to the liquid side of the heat source heat exchanger 33 and the liquid refrigerant connecting pipe 51. A heat source expansion valve 34 is installed on the liquid refrigerant pipe 54d. A liquid shut-off valve 37 is installed at the connection between the liquid refrigerant pipe 54d and the liquid refrigerant connecting pipe 51. The gaseous refrigerant pipe 54e connects to the flow path switching valve 32 and the gaseous refrigerant connecting pipe 52. A gas shut-off valve 38 is installed at the connection between the gaseous refrigerant pipe 54e and the refrigerant connecting pipe 52. Both the liquid shut-off valve 37 and the gas shut-off valve 38 are manually operated valves.

[0043] (2-2-1) Compressor

[0044] like Figure 1 As shown, compressor 31 draws in low-pressure refrigerant from suction pipe 54a and compresses the refrigerant through a compression mechanism (not shown), and discharges the compressed refrigerant to discharge pipe 54b.

[0045] The compressor 31 is, for example, a rotary or turbine compressor of equal displacement. The compression mechanism of the compressor 31 is driven by a compressor motor 31m. The speed of the compressor motor 31m can be controlled by an inverter.

[0046] (2-2-2) Flow path switching valve

[0047] The flow path switching valve 32 is a mechanism that switches the refrigerant flow path between a first state and a second state. In the first state, the flow path switching valve 32, as... Figure 1 As shown by the solid line inside the flow path switching valve 32, it connects the suction pipe 54a to the gaseous refrigerant piping 54e and the discharge pipe 54b to the gaseous refrigerant piping 54c. In the second state, the flow path switching valve 32, as... Figure 1 As shown by the dashed line inside the flow path switching valve 32, it connects the suction pipe 54a to the gas refrigerant piping 54c and the discharge pipe 54b to the gas refrigerant piping 54e.

[0048] During refrigeration operation, the flow path switching valve 32 sets the refrigerant flow path to the first state. At this time, the refrigerant discharged from the compressor 31 flows sequentially through the heat source heat exchanger 33, the heat source expansion valve 34, the expansion valve 23, and the heat exchanger 21 within the refrigerant circuit 50, and returns to the compressor 31. In the first state, the heat source heat exchanger 33 functions as a condenser, and the heat exchanger 21 functions as an evaporator.

[0049] During heating operation, the flow path switching valve 32 sets the refrigerant flow path to the second state. In this state, the refrigerant discharged from the compressor 31 flows sequentially through the heat exchanger 21, the expansion valve 23, the heat source expansion valve 34, and the heat source heat exchanger 33 within the refrigerant circuit 50, and then returns to the compressor 31. In the second state, the heat source heat exchanger 33 functions as an evaporator, and the heat exchanger 21 functions as a condenser.

[0050] (2-2-3) Heat source heat exchanger

[0051] The heat source heat exchanger 33 enables heat exchange between the refrigerant flowing through the heat source heat exchanger 33 and the air surrounding the heat source unit 30. The heat source heat exchanger 33 is, for example, a finned tube heat exchanger having multiple heat transfer fins and multiple heat transfer tubes.

[0052] (2-2-4) Heat source expansion valve

[0053] The heat source expansion valve 34 is a mechanism used to regulate the pressure and flow rate of the refrigerant flowing in the liquid refrigerant piping 54d. For example... Figure 1 As shown, the heat source expansion valve 34 is located on the liquid refrigerant piping 54d. The heat source expansion valve 34 is an electrically operated valve with an adjustable opening.

[0054] (2-2-5) Storage tank

[0055] Storage tank 35 is a container with a gas-liquid separation function that separates the incoming refrigerant into gaseous and liquid refrigerant. For example... Figure 1 As shown, the storage tank 35 is located at the suction pipe 54a. The refrigerant flowing into the storage tank 35 is separated into gaseous refrigerant and liquid refrigerant, and the gaseous refrigerant that accumulates in the upper space flows into the compressor 31.

[0056] (2-2-6) Heat source fan

[0057] The heat source fan 36 supplies air from around the heat source unit 30 to the heat source heat exchanger 33. The heat source fan 36 is, for example, an axial fan such as a propeller fan. Figure 1 As shown, the heat source fan 36 is driven by the heat source fan motor 36m. The speed of the heat source fan motor 36m can be controlled by an inverter.

[0058] (2-2-7) Sensor

[0059] The suction pressure sensor 68 is a sensor that measures the suction pressure of the compressor 31. The suction pressure sensor 68 is located on the suction pipe 54a. The suction pressure is the refrigerant pressure corresponding to the evaporation pressure during refrigeration operation.

[0060] The discharge pressure sensor 69 is a sensor that measures the discharge pressure of the compressor 31. The discharge pressure sensor 69 is located on the discharge pipe 54b. The discharge pressure is the refrigerant pressure corresponding to the condensing pressure during heating operation.

[0061] (2-2-8) Heat Source Control Department

[0062] The heat source control unit 39 is connected to the various devices in the heat source unit 30 in a communicable manner. The various devices in the heat source unit 30 include a compressor motor 31m, a flow path switching valve 32, a heat source expansion valve 34, a heat source fan motor 36m, an intake pressure sensor 68, and an exhaust pressure sensor 69.

[0063] The heat source control unit 39 includes a control and arithmetic unit and a storage device. The control and arithmetic unit is a processor such as a CPU or GPU. The storage device is a storage medium such as RAM, ROM, or flash memory. The control and arithmetic unit reads the program stored in the storage device and performs the prescribed calculations according to the program, thereby controlling the operation of various devices in the heat source unit 30. In addition, the control and arithmetic unit can write the calculation results to the storage device according to the program, and can also read the information stored in the storage device according to the program.

[0064] The heat source control unit 39 exchanges control signals, measurement signals, and signals related to various settings with the utilization control unit 29 of the utilization unit 20 and the opening control unit 89 of the opening adjustment unit 80 via a communication line. The heat source control unit 39, the utilization control unit 29, and the opening control unit 89 cooperate to function as the control unit 40.

[0065] (2-3) Opening adjustment unit

[0066] Since the opening adjustment units 80 and 80a have basically the same structure, the opening adjustment unit 80 will be described below.

[0067] like Figure 1 As shown, the opening adjustment unit 80 is provided for the utilization unit 20. The opening adjustment unit 80 includes a liquid opening adjustment valve 81, a gas opening adjustment valve 82, and an opening control unit 89.

[0068] The liquid opening regulating valve 81 is installed on the liquid refrigerant connecting pipe 55 connected to the utilization unit 20. In other words, the liquid opening regulating valve 81 is installed on the liquid side of the liquid refrigerant connecting pipe 55 connected to the utilization unit 20.

[0069] The gas opening regulating valve 82 is installed on the gas refrigerant connecting pipe 56 connected to the utilization unit 20. In other words, the gas opening regulating valve 82 (first opening regulating valve) is installed on the gas side of the gas refrigerant connecting pipe 56 (first refrigerant pipe) connected to the utilization unit 20.

[0070] The liquid opening regulating valve 81 and the gas opening regulating valve 82 are electrically operated valves with adjustable opening. Furthermore, when the liquid opening regulating valve 81 is fully closed, it functions as a shut-off valve to block the refrigerant flowing in the liquid refrigerant connecting pipe 55. When the gas opening regulating valve 82 is fully closed, it functions as a shut-off valve to block the refrigerant flowing in the gas refrigerant connecting pipe 56.

[0071] The opening control unit 89 is connected to the various devices of the opening adjustment unit 80 in a communicable manner. The various devices of the opening adjustment unit 80 include a liquid opening adjustment valve 81 and a gas opening adjustment valve 82.

[0072] The opening control unit 89 includes a control arithmetic unit and a storage unit. The control arithmetic unit is a processor such as a CPU or GPU. The storage unit is a storage medium such as RAM, ROM, or flash memory. The control arithmetic unit reads the program stored in the storage unit and performs prescribed calculations according to the program, thereby controlling the operation of various devices in the heat source unit 30. In addition, the control arithmetic unit can write the calculation results to the storage unit according to the program and can also read the information stored in the storage unit according to the program.

[0073] The opening control unit 89 exchanges control signals, measurement signals, and signals related to various settings with the utilization control unit 29 of the utilization unit 20 and the heat source control unit 39 of the heat source unit 30 via a communication line. The opening control unit 89, the utilization control unit 29, and the heat source control unit 39 cooperate to function as the control unit 40.

[0074] (2-4) Control Department

[0075] The control unit 40 consists of a utilization control unit 29, a heat source control unit 39, and an opening control unit 89. The control unit 40 causes the control calculation devices of the utilization control unit 29, the heat source control unit 39, and the opening control unit 89 to execute programs stored in their respective storage devices, thereby controlling the operation of the refrigeration cycle unit 1 as a whole.

[0076] Figure 2 This is a control block diagram showing the refrigeration cycle apparatus 1 of this embodiment. (As shown) Figure 2As shown, the control unit 40 is communicatively connected to the expansion valve 23, the fan motor 22m, the refrigerant sensor 61, the saturation temperature sensor 64, the compressor motor 31m, the flow path switching valve 32, the heat source expansion valve 34, the heat source fan motor 36m, the suction pressure sensor 68, the discharge pressure sensor 69, the liquid opening regulating valve 81, and the gas opening regulating valve 82. The control unit 40 controls the operation of various devices in the refrigeration cycle unit 1 based on control signals received from the operating remote control via the unit 20 and measurement signals from various sensors.

[0077] The control unit 40 mainly performs refrigeration and heating operations. In addition, the control unit 40 mainly has a refrigerant leakage prevention function.

[0078] (2-4-1) Refrigeration operation

[0079] When the control unit 40 receives an instruction to perform refrigeration operation from the operating remote control via the utilization unit 20, for example, the flow path switching valve 32 is switched to the first state.

[0080] Then, the control unit 40 sets the heat source expansion valve 34 to full open and controls the liquid opening regulating valve 81, the gas opening regulating valve 82, the compressor motor 31m, and the expansion valve 23 to make the measured value of the saturation temperature sensor 64, i.e., the evaporation temperature, the target evaporation temperature. In particular, the control unit 40 controls the gas opening regulating valve 82 to adjust the evaporation temperature of the refrigerant flowing in the heat exchanger 21. For example, the control unit 40 reduces the opening of the gas opening regulating valve 82 to increase the evaporation temperature of the refrigerant flowing in the heat exchanger 21. The target evaporation temperature is set, for example, according to the set temperature received from the operating remote control.

[0081] As described above, by controlling the operation of various devices, the refrigerant in the refrigerant circuit 50 flows in the following manner during refrigeration operation.

[0082] When compressor 31 starts, low-pressure gaseous refrigerant is drawn into compressor 31 and compressed into high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant is conveyed to heat source heat exchanger 33 via flow path switching valve 32, where it exchanges heat with the air surrounding heat source unit 30 supplied by heat source fan 36, condensing into high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows in liquid refrigerant piping 54d and passes through heat source expansion valve 34. The high-pressure liquid refrigerant conveyed to utilization unit 20 is depressurized to near the suction pressure of compressor 31 in utilization expansion valve 23, thus becoming a gas-liquid two-phase refrigerant and conveyed to utilization heat exchanger 21. The gas-liquid two-phase refrigerant in utilization heat exchanger 21 exchanges heat with the air in the target space supplied to utilization heat exchanger 21 by utilization fan 22a, evaporating and becoming low-pressure gaseous refrigerant. Low-pressure gaseous refrigerant is delivered to the heat source unit 30 via gaseous refrigerant connecting pipe 52 and flows into the storage tank 35 via flow path switching valve 32. The low-pressure gaseous refrigerant flowing into the storage tank 35 is then drawn back into the compressor 31. The temperature of the air supplied to the heat exchanger 21 is reduced by heat exchange with the refrigerant flowing through the heat exchanger 21, and the cooled air in the heat exchanger 21 is blown out into the target space.

[0083] (2-4-2) Heating Operation

[0084] When the control unit 40 receives an instruction from the operating remote control via the utilization unit 20, indicating that heating operation is to be performed, it switches the flow path switching valve 32 to the second state.

[0085] Then, the control unit 40 controls the liquid opening regulating valve 81, the gas opening regulating valve 82, the compressor motor 31m, and the expansion valve 23 to make the measured value of the saturation temperature sensor 64, i.e., the condensing temperature, the target condensing temperature. In particular, the control unit 40 controls the gas opening regulating valve 82 to regulate the condensing temperature of the refrigerant flowing in the heat exchanger 21. For example, the control unit 40 reduces the opening of the gas opening regulating valve 82, thereby lowering the condensing temperature of the refrigerant flowing in the heat exchanger 21. The target condensing temperature is set, for example, according to the set temperature received from the operating remote control. Furthermore, the control unit 40 controls the opening of the heat source expansion valve 34 to depressurize the refrigerant flowing into the heat source heat exchanger 33 to a pressure that allows evaporation.

[0086] When compressor 31 starts, low-pressure gaseous refrigerant is drawn into compressor 31 and compressed into high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant is conveyed to heat exchanger 21 via flow path switching valve 32, where it exchanges heat with air supplied to the target space via fan 22, condensing into high-pressure liquid refrigerant. The temperature of the air supplied to heat exchanger 21 rises through heat exchange with the refrigerant flowing through it, and the heated air is blown out of the target space. The high-pressure liquid refrigerant after passing through heat exchanger 21 is depressurized in expansion valve 23. The depressurized liquid refrigerant is then conveyed to heat source unit 30 via liquid refrigerant connecting pipe 51 and flows into liquid refrigerant pipe 54d. The refrigerant flowing in the liquid refrigerant line 54d is depressurized in the heat source expansion valve 34 to near the suction pressure of the compressor 31, becoming a gas-liquid two-phase refrigerant, and flows into the heat source heat exchanger 33. The low-pressure gas-liquid two-phase refrigerant flowing into the heat source heat exchanger 33 exchanges heat with the air surrounding the heat source unit 30 supplied by the heat source fan 36 and evaporates, becoming a low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant flows into the storage tank 35 via the flow path switching valve 32. The low-pressure gaseous refrigerant flowing into the storage tank 35 is then drawn back into the compressor 31.

[0087] (2-4-3) Refrigerant Leakage Prevention Function

[0088] When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 sets the liquid opening regulating valve 81 to fully close, thereby blocking the refrigerant leaking from the utilization unit 20 via the liquid refrigerant connecting pipe 55. When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 sets the gas opening regulating valve 82 to fully close, thereby blocking the refrigerant leaking from the utilization unit 20 via the gas refrigerant connecting pipe 56. The control unit 40 may also set the utilization expansion valve 23 to fully close.

[0089] By fully closing the liquid opening regulating valve 81 and the gas opening regulating valve 82, the pressure of the refrigerant flowing in other utilization units (e.g., utilization unit 20a) increases, potentially causing damage to those units. Therefore, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 controls the compressor 31 based on the pressure change of the refrigerant flowing in the refrigerant circuit 50 caused by fully closing the gas opening regulating valve 82. For example, if the measurement value of the suction pressure sensor 68 increases due to fully closing the gas opening regulating valve 82, the control unit 40 reduces the speed of the compressor motor 31m.

[0090] (3) Characteristics

[0091] (3-1)

[0092] Conventional techniques exist for controlling the opening of a regulating valve located in the utilization unit, thereby controlling the evaporation or condensation temperature within the unit. To address the possibility of refrigerant leakage within the utilization unit, it is desirable to install a shut-off valve to prevent refrigerant leakage. However, installing a shut-off valve in addition to the regulating valve presents a technical problem: it complicates the structure of the refrigeration cycle unit.

[0093] The refrigeration cycle apparatus 1 of this embodiment includes a heat source unit 30, multiple utilization units 20, 20a, a gas opening regulating valve 82, and a control unit 40. The heat source unit 30 includes a compressor 31. The multiple utilization units 20, 20a, together with the heat source unit 30, constitute a refrigerant circuit 50. The multiple utilization units 20, 20a include a utilization unit 20. The gas opening regulating valve 82 is provided for the utilization unit 20. The utilization unit 20 includes a refrigerant sensor 61. The refrigerant sensor 61 detects refrigerant leakage. The control unit 40 controls the gas opening regulating valve 82 to adjust the evaporation temperature or condensation temperature in the utilization unit 20. When the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 sets the gas opening regulating valve 82 to full closure, thereby blocking the refrigerant leakage from the utilization unit 20.

[0094] In the refrigeration cycle unit 1, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 sets the gas opening regulating valve 82 to full closure, thereby blocking the refrigerant leaking from the utilization unit 20. As a result, the refrigeration cycle unit 1 uses the gas opening regulating valve 82 as a shut-off valve to block the refrigerant leaking from the utilization unit 20, thereby simplifying the structure of the refrigeration cycle unit 1.

[0095] (3-2)

[0096] In the refrigeration cycle unit 1, a gas opening regulating valve 82 is installed on the gas refrigerant communication pipe 56 connected to the utilization unit 20 on the gas side. When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 sets the gas opening regulating valve 82 to be fully closed, thereby blocking the refrigerant leaking from the utilization unit 20 through the gas refrigerant communication pipe 56.

[0097] (3-3)

[0098] In the refrigeration cycle device 1, the control unit 40 controls the gas opening regulating valve 82 so that the evaporation temperature or condensation temperature in the utilization unit 20 becomes the target evaporation temperature or target condensation temperature.

[0099] (3-4)

[0100] In the refrigeration cycle unit 1, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 controls the compressor 31 based on the pressure change of the refrigerant flowing in the refrigerant circuit 50 caused by setting the gas opening regulating valve 82 to be fully closed.

[0101] As a result, the refrigeration cycle unit 1 can prevent damage to other utilization units caused by increasing the pressure of the refrigerant flowing in other utilization units due to setting the gas opening regulating valve 82 to be fully closed.

[0102] (4) Variations

[0103] (4-1) Variation 1A

[0104] In this embodiment, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 controls the compressor 31 based on the pressure change of the refrigerant flowing in the refrigerant circuit 50 caused by setting the gas opening regulating valve 82 to be fully closed.

[0105] However, if the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 can also control the compressor 31 based on the state of the utilization unit 20 after setting the gas opening regulating valve 82 to full closure. The state of the utilization unit 20 includes the capacity of the utilization unit 20 or the opening degree of the gas opening regulating valve 82. For example, if the capacity of the utilization unit 20 is relatively large, setting the gas opening regulating valve 82 to full closure by the control unit 40 may increase the pressure of the refrigerant flowing in other utilization units. Therefore, if the capacity of the utilization unit 20 is relatively large, the control unit 40 reduces the speed of the compressor motor 31m after setting the gas opening regulating valve 82 to full closure. Furthermore, for example, if the opening degree of the gas opening regulating valve 82 is relatively large before being set to full closure, setting the gas opening regulating valve 82 to full closure by the control unit 40 may increase the pressure of the refrigerant flowing in other utilization units. Therefore, when the opening of the gas opening regulating valve 82 is relatively large before it is set to fully closed, the control unit 40 reduces the speed of the compressor motor 31m after setting the gas opening regulating valve 82 to fully closed.

[0106] Furthermore, the state of utilization unit 20 may also include the opening degree of expansion valve 23. For example, if the opening degree of expansion valve 23 is relatively large before gas opening regulating valve 82 is fully closed, the control unit 40 may close gas opening regulating valve 82, increasing the pressure of refrigerant flowing in other utilization units. Therefore, if the opening degree of expansion valve 23 is relatively large before gas opening regulating valve 82 is fully closed, the control unit 40 reduces the speed of compressor motor 31m after closing gas opening regulating valve 82.

[0107] As a result, the refrigeration cycle unit 1 can prevent damage to other utilization units caused by increasing the pressure of the refrigerant flowing in other utilization units due to setting the gas opening regulating valve 82 to be fully closed.

[0108] In addition, if the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 can also set the gas opening regulating valve 82 to be fully closed after controlling the compressor 31 based on the state of the utilization unit 20.

[0109] (4-2) Variation 1B

[0110] The opening adjustment unit 80 can be set for each of the multiple utilization units connected to the heat source unit 30, or it can be set for a portion of the multiple utilization units.

[0111] (4-3) Variation 1C

[0112] The refrigeration cycle unit 1 can also be a multi-split air conditioning system for buildings, consisting of multiple utilization units connected to the heat source unit 30, each capable of independently performing refrigeration and heating operations.

[0113] (4-4)

[0114] The embodiments of this disclosure have been described above. However, it should be understood that various changes in form and detail can be made without departing from the spirit and scope of this disclosure as set forth in the claims.

[0115] <Second Implementation>

[0116] The following description focuses on the differences from the first embodiment.

[0117] Figure 3 This is a diagram showing the refrigerant circuit 50 of the refrigeration cycle apparatus 1 according to this embodiment. Figure 3 As shown, the opening adjustment unit 801 in this embodiment is different from the opening adjustment unit 80 in the first embodiment, and it does not have a liquid opening adjustment valve 81.

[0118] When operating in both cooling and heating modes, the expansion valve 23 functions as a liquid opening regulating valve 81.

[0119] As a result, the refrigeration cycle unit 1 uses the gas opening regulating valve 82 as a shut-off valve to block refrigerant leakage from the utilization unit 20, thereby simplifying the structure of the refrigeration cycle unit 1.

[0120] The opening adjustment unit 801 can be set for each of the multiple utilization units connected to the heat source unit 30, or it can be set for a portion of the multiple utilization units. Furthermore, as... Figure 3 As shown, an opening adjustment unit 801 can also be set for the utilization unit 20, an opening adjustment unit 80a can be set for the utilization unit 20a, or different types of opening adjustment units can be set for each of the multiple utilization units.

[0121] The embodiments of this disclosure have been described above. However, it should be understood that various changes in form and detail can be made without departing from the spirit and scope of this disclosure as set forth in the claims.

[0122] Symbol Explanation

[0123] 1. Refrigeration circulation unit; 20 Utilization Unit (First Utilization Unit); 20a Utilization Unit; 23. Utilize an expansion valve (second opening regulating valve); 30 heat source units; 31. Compressor; 40. Control Department; 50. Refrigerant circuit; 56. Gas refrigerant connection piping (first refrigerant piping); 61 Refrigerant sensor (first sensor); 82 Gas opening control valve (first opening control valve).

[0124] Existing technical documents

[0125] Patent documents

[0126] Patent Document 1: Japanese Patent Application Publication No. 2008-281304

Claims

1. A refrigeration cycle apparatus (1) characterized by comprising: include: Heat source unit (30), the heat source unit having a compressor (31); Multiple utilization units (20, 20a) together with the heat source unit constitute a refrigerant circuit (50), and include a first utilization unit (20). A first opening regulating valve (82) is provided for the first utilization unit; and Control unit (40). The first utilization unit has a first sensor (61) that detects refrigerant leakage. The control unit controls the first opening regulating valve, thereby adjusting the evaporation temperature or condensation temperature in the first utilization unit. If the first sensor detects a refrigerant leak, the control unit sets the first opening adjustment valve to be fully closed, thereby blocking the refrigerant leaking from the first utilization unit.

2. The refrigeration cycle device (1) according to claim 1, characterized in that, The first opening regulating valve is located on the first refrigerant piping (56) on the gas side connected to the first utilization unit. When the first sensor detects a refrigerant leak, the control unit sets the first opening regulating valve to be fully closed, thereby blocking the refrigerant leaking from the first utilization unit through the first refrigerant piping.

3. The refrigeration cycle apparatus (1) according to claim 1 or 2, characterized in that, The control unit controls the first opening adjustment valve so that the evaporation temperature or condensation temperature in the first utilization unit becomes the target evaporation temperature or target condensation temperature.

4. The refrigeration cycle apparatus (1) according to any one of claims 1 to 3, characterized in that, When the first sensor detects a refrigerant leak, the control unit controls the compressor based on the pressure change of the refrigerant flowing in the refrigerant circuit caused by setting the first opening regulating valve to be fully closed.

5. The refrigeration cycle apparatus (1) according to any one of claims 1 to 3, characterized in that, When the first sensor detects a refrigerant leak, the control unit controls the compressor based on the state of the first utilization unit.

6. The refrigeration cycle apparatus (1) according to claim 5, characterized in that, The state of the first utilization unit includes the capacity of the first utilization unit or the opening degree of the first opening degree regulating valve.

7. The refrigeration cycle apparatus (1) according to claim 5, characterized in that, The first utilization unit has a second opening adjustment valve (23) inside. The state of the first utilization unit includes the opening degree of the second opening degree regulating valve.

Images