Refrigeration cycle device

Abstract

To solve the problem in which, when a cutoff valve is provided separately from an opening adjustment valve, the structure of a refrigerant cycle device becomes complicated.SOLUTION: A refrigeration cycle device 1 includes a heat source unit 30, a plurality of utilization units 20, 20a, a gas opening adjustment valve 82, and a control part 40. The gas opening adjustment valve 82 is provided with respect to the utilization unit 20. The utilization unit 20 has a refrigerant sensor 61. The refrigerant sensor 61 detects the leakage of a refrigerant. The control part 40 controls the gas opening adjustment valve 82, and adjusts an evaporation temperature or a condensation temperature in the utilization unit 20. In the case where the refrigerant sensor 61 detects the leakage of the refrigerant, by fully closing the gas opening adjustment valve 82, the control part 40 cuts off the refrigerant leaking from the utilization unit 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] It relates to a refrigeration cycle device.

Background Art

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

Summary of the Invention

Problems to be Solved by the Invention

[0003] In case the refrigerant leaks in the utilization unit, it is desirable to provide a shut-off valve for shutting off the refrigerant leakage for the utilization unit. However, providing a shut-off valve separately from the opening degree adjustment valve has a problem that the structure of the refrigeration cycle device becomes complicated.

Means for Solving the Problems

[0004] The refrigeration cycle device of the first aspect includes a heat source unit, a plurality of utilization units, a first opening degree adjustment valve, and a control unit. The heat source unit has a compressor. The plurality of utilization units constitute a refrigerant circuit together with the heat source unit. The plurality of utilization units include a first utilization unit. The first opening degree adjustment 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 degree adjustment valve to adjust the evaporation temperature or the condensation temperature in the first utilization unit. When the first sensor detects refrigerant leakage, the control unit closes the first opening degree adjustment valve completely to shut off the refrigerant leaking from the first utilization unit.

[0005] In the refrigeration cycle device of the first aspect, when the first sensor detects refrigerant leakage, the control unit closes the first opening degree adjustment valve completely, thereby blocking the refrigerant leaking from the first utilization unit. As a result, the refrigeration cycle device can simplify the structure of the refrigeration cycle device by using the first opening degree adjustment valve as a shut-off valve that blocks the refrigerant leaking from the first utilization unit.

[0006] The refrigeration cycle device of the second aspect is the refrigeration cycle device of the first aspect, wherein the first opening degree adjustment valve is provided in the first refrigerant pipe on the gas side connected to the first utilization unit. When the first sensor detects refrigerant leakage, the control unit closes the first opening degree adjustment valve completely, thereby blocking the refrigerant leaking from the first utilization unit through the first refrigerant pipe.

[0007] The refrigeration cycle device of the third aspect is the refrigeration cycle device of the first aspect or the second aspect, wherein the control unit controls the first opening degree adjustment valve so that the evaporation temperature or the condensation temperature in the first utilization unit becomes the target evaporation temperature or the target condensation temperature.

[0008] The refrigeration cycle device of the fourth aspect is the refrigeration cycle device of any one of the first aspect to the third aspect. When the first sensor detects refrigerant leakage, the control unit controls the compressor based on the pressure fluctuation of the refrigerant flowing in the refrigerant circuit by closing the first opening degree adjustment valve completely.

[0009] With such a configuration, the refrigeration cycle device of the fourth aspect can prevent the pressure of the refrigerant flowing in other utilization units from increasing and other utilization units from being damaged.

[0010] The refrigeration cycle device of the fifth aspect is the refrigeration cycle device of any one of the first aspect to the third aspect. When the first sensor detects refrigerant leakage, the control unit controls the compressor based on the state of the first utilization unit.

[0011] The refrigeration cycle device from the fifth perspective, with such a configuration, can prevent the pressure of the refrigerant flowing in other utilization units from increasing and prevent damage to other utilization units.

[0012] The refrigeration cycle device from the sixth perspective is the refrigeration cycle device from the fifth perspective, 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 adjustment valve.

[0013] The refrigeration cycle device from the seventh perspective is the refrigeration cycle device from the fifth perspective, and the first utilization unit has a second opening degree adjustment valve inside. The state of the first utilization unit includes the opening degree of the second opening degree adjustment valve.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0015] <First Embodiment> (1) Overall Configuration The refrigeration cycle device 1 constitutes a vapor compression refrigeration cycle and performs air conditioning of the target space. In this embodiment, the refrigeration cycle device 1 is a so-called multi-type air conditioning system for buildings. FIG. 1 is a diagram showing the refrigerant circuit 50 of the refrigeration cycle device 1 in this embodiment. As shown in FIG. 1, the refrigeration cycle device 1 mainly includes a heat source unit 30, a plurality of utilization units 20, 20a, opening degree adjustment units 80, 80a, and a control unit 40. The heat source unit 30 and the plurality of utilization units 20, 20a are connected by a liquid refrigerant connection pipe 51 and a gas refrigerant connection pipe 52 to constitute the refrigerant circuit 50. The heat source unit 30, the plurality of utilization units 20, 20a, and the opening degree adjustment units 80, 80a are communicably connected by a communication line (not shown). In FIG. 1, for example, two utilization units 20, 20a are described, but the number of the plurality of utilization units connected to the heat source unit 30 is arbitrary.

[0016] (2) Detailed configuration (2-1) Utilization unit Since the structures of the utilization units 20, 20a are basically the same, the utilization unit 20 (the first utilization unit) will be described below.

[0017] The utilization unit 20 is installed in the target space within the building where the refrigeration cycle device 1 is installed. The utilization unit 20 is, for example, a ceiling-embedded type unit, a ceiling-suspended type unit, a floor-mounted type unit, etc. As shown in FIG. 1, the utilization unit 20 mainly includes a utilization heat exchanger 21, a utilization fan 22, a utilization expansion valve 23 (the second opening degree adjustment valve), a utilization control unit 29, a refrigerant sensor 61 (the first sensor), and a saturation temperature sensor 64. Further, the utilization unit 20 has a liquid refrigerant pipe 57 that connects the liquid side end of the utilization heat exchanger 21 and a liquid refrigerant connection pipe 55 where the liquid refrigerant connection pipe 51 branches to the utilization unit 20 side. The utilization unit 20 has a gas refrigerant pipe 58 that connects the gas side end of the utilization heat exchanger 21 and a gas refrigerant connection pipe 56 where the gas refrigerant connection pipe 52 branches to the utilization unit 20 side. The liquid refrigerant pipe 57 and the gas refrigerant pipe 58 are provided inside the utilization unit 20.

[0018] (2-1-1) Using a heat exchanger The utilization heat exchanger 21 causes heat exchange between the refrigerant flowing in the utilization heat exchanger 21 and the air in the target space. The utilization heat exchanger 21 is, for example, a fin-and-tube type heat exchanger having a plurality of heat transfer fins and a plurality of heat transfer tubes.

[0019] (2-1-2) Utilization fan The utilization fan 22 supplies the air in the target space to the utilization heat exchanger 21. The utilization fan 22 is, for example, a centrifugal fan such as a turbo fan or a sirocco fan. As shown in FIG. 1, the utilization fan 22 is driven by a utilization fan motor 22m. The rotation speed of the utilization fan motor 22m can be controlled by an inverter.

[0020] (2-1-3) Utilization expansion valve The utilization expansion valve 23 is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 57. The utilization expansion valve 23 is provided in the liquid refrigerant pipe 57. The utilization expansion valve 23 is an electric valve whose opening degree can be adjusted.

[0021] (2-1-4) Sensor The refrigerant sensor 61 detects refrigerant leakage. The refrigerant sensor 61 is provided, for example, near the utilization heat exchanger 21.

[0022] The saturation temperature sensor 64 measures the temperature of the refrigerant flowing through the utilization heat exchanger 21. The saturation temperature sensor 64 measures the evaporation temperature of the refrigerant flowing through the utilization heat exchanger 21 during the cooling operation. The saturation temperature sensor 64 measures the condensation temperature of the refrigerant flowing through the utilization heat exchanger 21 during the heating operation. The saturation temperature sensor 64 is provided in the utilization heat exchanger 21.

[0023] (2-1-5) Utilization control unit The utilization control unit 29 is communicably connected to various devices included in the utilization unit 20, including the utilization expansion valve 23, the utilization fan motor 22m, the refrigerant sensor 61, and the saturation temperature sensor 64.

[0024] The utilization control unit 29 includes a control arithmetic unit and a storage device. The control arithmetic unit is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic unit reads a program stored in the storage device and performs predetermined arithmetic processing according to the program, thereby controlling the operations of various devices included in the utilization unit 20. Further, the control arithmetic unit can write an arithmetic result to the storage device or read information stored in the storage device according to the program.

[0025] The utilization control unit 29 is configured to be able to receive various signals transmitted from an operation remote controller (not shown). The various signals include, for example, a signal instructing the start or stop of operation and a signal related to various settings. The signals related to various settings include, for example, a signal related to the set temperature and the air volume.

[0026] The utilization control unit 29 exchanges control signals, measurement signals, signals related to various settings, etc. 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 utilization control unit 29, the heat source control unit 39, and the opening control unit 89 function as a control unit 40 in cooperation.

[0027] (2-2) Heat Source Unit The heat source unit 30 is installed on the rooftop of a building where the refrigeration cycle device 1 is installed. As shown in FIG. 1, 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, an accumulator 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. Further, the heat source unit 30 includes a suction pipe 54a, a discharge pipe 54b, gas refrigerant pipes 54c, 54e, and a liquid refrigerant pipe 54d.

[0028] The suction pipe 54a connects the flow path switching valve 32 and the suction side of the compressor 31. An accumulator 35 is provided in the suction pipe 54a. The discharge pipe 54b connects the discharge side of the compressor 31 and the flow path switching valve 32. The gas refrigerant pipe 54c connects the flow path switching valve 32 and the gas side end of the heat source heat exchanger 33. The liquid refrigerant pipe 54d connects the liquid side end of the heat source heat exchanger 33 and the liquid refrigerant connection pipe 51. A heat source expansion valve 34 is provided in the liquid refrigerant pipe 54d. A liquid shut-off valve 37 is provided at the connection portion between the liquid refrigerant pipe 54d and the liquid refrigerant connection pipe 51. The gas refrigerant pipe 54e connects the flow path switching valve 32 and the gas refrigerant connection pipe 52. A gas shut-off valve 38 is provided at the connection portion between the gas refrigerant pipe 54e and the gas refrigerant connection pipe 52. The liquid shut-off valve 37 and the gas shut-off valve 38 are valves that are manually opened and closed.

[0029] (2-2-1) Compressor As shown in FIG. 1, the compressor 31 sucks low-pressure refrigerant from the suction pipe 54a, compresses the refrigerant by a compression mechanism (not shown), and discharges the compressed refrigerant into the discharge pipe 54b.

[0030] The compressor 31 is, for example, a positive displacement compressor such as a rotary type or a scroll type. The compression mechanism of the compressor 31 is driven by a compressor motor 31m. The rotational speed of the compressor motor 31m can be controlled by an inverter.

[0031] (2-2-2) Flow Path Switching Valve The flow path switching valve 32 is a mechanism that switches the refrigerant flow path between a first state and a second state. When in the first state, as shown by the solid line in the flow path switching valve 32 in FIG. 1, the flow path switching valve 32 connects the suction pipe 54a to the gas refrigerant pipe 54e and connects the discharge pipe 54b to the gas refrigerant pipe 54c. When in the second state, as shown by the dashed line in the flow path switching valve 32 in FIG. 1, the flow path switching valve 32 connects the suction pipe 54a to the gas refrigerant pipe 54c and connects the discharge pipe 54b to the gas refrigerant pipe 54e.

[0032] During the cooling 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 through the refrigerant circuit 50 in the order of the heat source heat exchanger 33, the heat source expansion valve 34, the utilization expansion valve 23, and the utilization heat exchanger 21, and returns to the compressor 31. In the first state, the heat source heat exchanger 33 functions as a condenser, and the utilization heat exchanger 21 functions as an evaporator.

[0033] During the heating operation, the flow path switching valve 32 sets the refrigerant flow path to the second state. At this time, the refrigerant discharged from the compressor 31 flows through the refrigerant circuit 50 in the order of the utilization heat exchanger 21, the utilization expansion valve 23, the heat source expansion valve 34, and the heat source heat exchanger 33, and returns to the compressor 31. In the second state, the heat source heat exchanger 33 functions as an evaporator, and the utilization heat exchanger 21 functions as a condenser.

[0034] (2-2-3) Heat source heat exchanger The heat source heat exchanger 33 performs heat exchange between the refrigerant flowing through the heat source heat exchanger 33 and the air around the heat source unit 30. The heat source heat exchanger 33 is, for example, a fin-and-tube type heat exchanger having a plurality of heat transfer fins and a plurality of heat transfer tubes.

[0035] (2-2-4) Heat source expansion valve The heat source expansion valve 34 is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 54d. As shown in FIG. 1, the heat source expansion valve 34 is provided in the liquid refrigerant pipe 54d. The heat source expansion valve 34 is an electric valve whose opening can be adjusted.

[0036] (2-2-5) Accumulator The accumulator 35 is a container having a gas-liquid separation function for separating the incoming refrigerant into a gas refrigerant and a liquid refrigerant. As shown in FIG. 1, the accumulator 35 is provided in the suction pipe 54a. The refrigerant flowing into the accumulator 35 is separated into a gas refrigerant and a liquid refrigerant, and the gas refrigerant that gathers in the upper space flows into the compressor 31.

[0037] (2-2-6) Heat source fan The heat source fan 36 supplies air around the heat source unit 30 to the heat source heat exchanger 33. The heat source fan 36 is, for example, an axial flow fan such as a propeller fan. As shown in FIG. 1, the heat source fan 36 is driven by a heat source fan motor 36m. The rotation speed of the heat source fan motor 36m can be controlled by an inverter.

[0038] (2-2-7) Sensor The suction pressure sensor 68 is a sensor that measures the suction pressure of the compressor 31. The suction pressure sensor 68 is provided in the suction pipe 54a. The suction pressure is the refrigerant pressure corresponding to the evaporation pressure during the cooling operation.

[0039] The discharge pressure sensor 69 is a sensor that measures the discharge pressure of the compressor 31. The discharge pressure sensor 69 is provided in the discharge pipe 54b. The discharge pressure is the refrigerant pressure corresponding to the condensation pressure during the heating operation.

[0040] (2-2-8) Heat source control unit The heat source control unit 39 is communicably connected to various devices of the heat source unit 30, including 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, and the discharge pressure sensor 69.

[0041] The heat source control unit 39 has a control arithmetic device and a storage device. The control arithmetic device is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic device reads out the program stored in the storage device and performs a predetermined arithmetic process according to the program to control the operations of various devices of the heat source unit 30. Also, the control arithmetic device can write the arithmetic result to the storage device or read out the information stored in the storage device according to the program.

[0042] The heat source control unit 39 communicates control signals, measurement signals, signals related to various settings, etc. with the usage control unit 29 of the usage unit 20 and the opening degree control unit 89 of the opening degree adjustment unit 80 via a communication line. The heat source control unit 39, the usage control unit 29, and the opening degree control unit 89 cooperate to function as the control unit 40.

[0043] (2-3) Opening Degree Adjustment Unit Since the structures of the opening degree adjustment units 80 and 80a are basically the same, the opening degree adjustment unit 80 will be described below.

[0044] As shown in FIG. 1, the opening degree adjustment unit 80 is provided for the usage unit 20. The opening degree adjustment unit 80 includes a liquid opening degree adjustment valve 81, a gas opening degree adjustment valve 82, and an opening degree control unit 89.

[0045] The liquid opening degree adjustment valve 81 is provided in the liquid refrigerant connection pipe 55 connected to the usage unit 20. In other words, the liquid opening degree adjustment valve 81 is provided in the liquid side liquid refrigerant connection pipe 55 connected to the usage unit 20.

[0046] The gas opening degree adjustment valve 82 is provided in the gas refrigerant connection pipe 56 connected to the usage unit 20. In other words, the gas opening degree adjustment valve 82 (the first opening degree adjustment valve) is provided in the gas side gas refrigerant connection pipe 56 (the first refrigerant pipe) connected to the usage unit 20.

[0047] The liquid opening degree adjustment valve 81 and the gas opening degree adjustment valve 82 are electric valves capable of adjusting the opening degree. Further, when the liquid opening degree adjustment valve 81 is fully closed, the liquid opening degree adjustment valve 81 functions as a shut-off valve that shuts off the refrigerant flowing through the liquid refrigerant connection pipe 55. When the gas opening degree adjustment valve 82 is fully closed, the gas opening degree adjustment valve 82 functions as a shut-off valve that shuts off the refrigerant flowing through the gas refrigerant connection pipe 56.

[0048] The opening degree control unit 89 is communicably connected to various devices included in the opening degree adjustment unit 80, including the liquid opening degree adjustment valve 81 and the gas opening degree adjustment valve 82.

[0049] The opening control unit 89 includes a control arithmetic unit and a storage device. The control arithmetic unit is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic unit reads the program stored in the storage device and performs predetermined arithmetic processing according to the program, thereby controlling the operations of various devices included in the heat source unit 30. Further, the control arithmetic unit can write the arithmetic result to the storage device or read the information stored in the storage device according to the program.

[0050] The opening control unit 89 exchanges control signals, measurement signals, signals related to various settings, etc. with the usage control unit 29 of the usage 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 usage control unit 29, and the heat source control unit 39 function as a control unit 40 in cooperation.

[0051] (2-4) Control Unit The control unit 40 is composed of a usage control unit 29, a heat source control unit 39, and an opening control unit 89. The control unit 40 controls the operation of the entire refrigeration cycle device 1 by causing the control arithmetic units of the usage control unit 29, the heat source control unit 39, and the opening control unit 89 to execute the programs stored in their respective storage devices.

[0052] FIG. 2 is a control block diagram of the refrigeration cycle device 1 in the present embodiment. As shown in FIG. 2, the control unit 40 is communicably connected to a use expansion valve 23, a use fan motor 22m, a refrigerant sensor 61, a saturation temperature sensor 64, a compressor motor 31m, a flow path switching valve 32, a heat source expansion valve 34, a heat source fan motor 36m, a suction pressure sensor 68, a discharge pressure sensor 69, a liquid opening adjustment valve 81, and a gas opening adjustment valve 82. The control unit 40 controls the operations of various devices included in the refrigeration cycle device 1 based on control signals received from an operation remote control via the usage unit 20, measurement signals from various sensors, etc.

[0053] The control unit 40 mainly performs cooling operation and heating operation. Further, the control unit 40 mainly has a refrigerant leakage prevention function.

[0054] (2-4-1) Cooling operation When the control unit 40 receives an instruction to perform a cooling operation, for example, from an operation remote control via the usage unit 20, the control unit 40 switches the flow path switching valve 32 to the first state.

[0055] Then, the control unit 40 fully opens the heat source expansion valve 34 and controls the liquid opening degree adjustment valve 81, the gas opening degree adjustment valve 82, the compressor motor 31m, the usage expansion valve 23, etc., so that the evaporation temperature, which is the measured value of the saturation temperature sensor 64, becomes the target evaporation temperature. In particular, the control unit 40 controls the gas opening degree adjustment valve 82 to adjust the evaporation temperature of the refrigerant flowing through the usage heat exchanger 21. For example, the control unit 40 increases the evaporation temperature of the refrigerant flowing through the usage heat exchanger 21 by decreasing the opening degree of the gas opening degree adjustment valve 82. The target evaporation temperature is set according to, for example, the set temperature received from the operation remote control.

[0056] As described above, by controlling the operations of various devices, during the cooling operation, the refrigerant flows through the refrigerant circuit 50 as follows.

[0057] When the compressor 31 is started, a low-pressure gas refrigerant is sucked into the compressor 31 and compressed by the compressor 31 to become a high-pressure gas refrigerant. The high-pressure gas refrigerant is sent to the heat source heat exchanger 33 via the flow path switching valve 32, exchanges heat with the air around the heat source unit 30 supplied by the heat source fan 36, condenses, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows through the liquid refrigerant pipe 54d and passes through the heat source expansion valve 34. The high-pressure liquid refrigerant sent to the utilization unit 20 is decompressed to near the suction pressure of the compressor 31 at the utilization expansion valve 23, becomes a refrigerant in a gas-liquid two-phase state, and is sent to the utilization heat exchanger 21. The refrigerant in the gas-liquid two-phase state exchanges heat with the air in the target space supplied to the utilization heat exchanger 21 by the utilization fan 22 in the utilization heat exchanger 21, evaporates, and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerant is sent to the heat source unit 30 via the gas refrigerant connection pipe 52 and flows into the accumulator 35 via the flow path switching valve 32. The low-pressure gas refrigerant flowing into the accumulator 35 is sucked into the compressor 31 again. The temperature of the air supplied to the utilization heat exchanger 21 decreases by exchanging heat with the refrigerant flowing through the utilization heat exchanger 21, and the air cooled by the utilization heat exchanger 21 blows out into the target space.

[0058] (2-4-2) Heating operation When the control unit 40 receives an instruction to perform a heating operation, for example, from an operation remote control via the utilization unit 20, it switches the flow path switching valve 32 to the second state.

[0059] Then, the control unit 40 controls the liquid opening adjustment valve 81, the gas opening adjustment valve 82, the compressor motor 31m, the utilization expansion valve 23, etc. so that the condensation temperature, which is the measured value of the saturation temperature sensor 64, becomes the target condensation temperature. In particular, the control unit 40 controls the gas opening adjustment valve 82 to adjust the condensation temperature of the refrigerant flowing through the utilization heat exchanger 21. For example, the control unit 40 decreases the opening of the gas opening adjustment valve 82 to lower the condensation temperature of the refrigerant flowing through the utilization heat exchanger 21. The target condensation temperature is set according to, for example, the set temperature received from the operation remote control. Further, the control unit 40 controls the opening of the heat source expansion valve 34 so that the refrigerant flowing into the heat source heat exchanger 33 is decompressed to a pressure at which it can evaporate in the heat source heat exchanger 33.

[0060] When the compressor 31 is started, low-pressure gas refrigerant is sucked into the compressor 31, compressed by the compressor 31, and becomes high-pressure gas refrigerant. The high-pressure gas refrigerant is sent to the utilization heat exchanger 21 via the flow path switching valve 32, and exchanges heat with the air in the target space supplied to the utilization heat exchanger 21 by the utilization fan 22, condenses, and becomes high-pressure liquid refrigerant. The temperature of the air supplied to the utilization heat exchanger 21 rises by exchanging heat with the refrigerant flowing through the utilization heat exchanger 21, and the air heated by the utilization heat exchanger 21 blows out into the target space. The high-pressure liquid refrigerant that has passed through the utilization heat exchanger 21 is depressurized by the utilization expansion valve 23. The depressurized liquid refrigerant is sent to the heat source unit 30 via the liquid refrigerant connection pipe 51 and flows into the liquid refrigerant pipe 54d. The refrigerant flowing through the liquid refrigerant pipe 54d is depressurized by the heat source expansion valve 34 to near the suction pressure of the compressor 31, becomes a refrigerant in a gas-liquid two-phase state, and flows into the heat source heat exchanger 33. The low-pressure gas-liquid two-phase state refrigerant flowing into the heat source heat exchanger 33 exchanges heat with the air around the heat source unit 30 supplied by the heat source fan 36 and evaporates, becoming low-pressure gas refrigerant. The low-pressure gas refrigerant flows into the accumulator 35 via the flow path switching valve 32. The low-pressure gas refrigerant flowing into the accumulator 35 is sucked into the compressor 31 again.

[0061] (2-4-3) Refrigerant leakage prevention function When the control unit 40 detects that the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 shuts off the refrigerant leaking from the utilization unit 20 through the liquid refrigerant connection pipe 55 by closing the liquid opening degree adjustment valve 81 completely. When the control unit 40 detects that the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 shuts off the refrigerant leaking from the utilization unit 20 through the gas refrigerant connection pipe 56 by closing the gas opening degree adjustment valve 82 completely. The control unit 40 may further close the utilization expansion valve 23 completely.

[0062] By closing the liquid opening degree adjustment valve 81 and the gas opening degree adjustment valve 82 completely, the pressure of the refrigerant flowing in other usage units (for example, usage unit 20a) increases, and there is a risk that other usage units may be damaged. Therefore, when the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 controls the compressor 31 based on the pressure fluctuation of the refrigerant flowing in the refrigerant circuit 50 due to closing the gas opening degree adjustment valve 82 completely. For example, when the measured value of the suction pressure sensor 68 increases by closing the gas opening degree adjustment valve 82 completely, the control unit 40 reduces the rotational speed of the compressor motor 31m.

[0063] (3) Features (3-1) Conventionally, there is a technology for controlling an opening degree adjustment valve provided for a usage unit to control the evaporation temperature or the condensation temperature in the usage unit. In case of refrigerant leakage in the usage unit, it is desirable to provide a shut-off valve for shutting off the refrigerant leakage for the usage unit. However, providing a shut-off valve separately from the opening degree adjustment valve has a problem that the structure of the refrigeration cycle apparatus becomes complicated.

[0064] The refrigeration cycle apparatus 1 of the present embodiment includes a heat source unit 30, a plurality of usage units 20, 20a, a gas opening degree adjustment valve 82, and a control unit 40. The heat source unit 30 has a compressor 31. The plurality of usage units 20, 20a constitute a refrigerant circuit 50 together with the heat source unit 30. The plurality of usage units 20, 20a include the usage unit 20. The gas opening degree adjustment valve 82 is provided for the usage unit 20. The usage unit 20 has a refrigerant sensor 61. The refrigerant sensor 61 detects refrigerant leakage. The control unit 40 controls the gas opening degree adjustment valve 82 to adjust the evaporation temperature or the condensation temperature in the usage unit 20. When the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 shuts off the refrigerant leaking from the usage unit 20 by closing the gas opening degree adjustment valve 82 completely.

[0065] In the refrigeration cycle device 1, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 shuts off the refrigerant leaking from the utilization unit 20 by fully closing the gas opening adjustment valve 82. As a result, the refrigeration cycle device 1 can simplify the structure of the refrigeration cycle device 1 by using the gas opening adjustment valve 82 as a shut-off valve that shuts off the refrigerant leaking from the utilization unit 20.

[0066] (3-2) In the refrigeration cycle device 1, the gas opening adjustment valve 82 is provided in the gas-side gas refrigerant communication pipe 56 connected to the utilization unit 20. When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 shuts off the refrigerant leaking from the utilization unit 20 through the gas refrigerant communication pipe 56 by fully closing the gas opening adjustment valve 82.

[0067] (3-3) In the refrigeration cycle device 1, the control unit 40 controls the gas opening adjustment valve 82 so that the evaporation temperature or the condensation temperature in the utilization unit 20 becomes the target evaporation temperature or the target condensation temperature.

[0068] (3-4) In the refrigeration cycle device 1, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 controls the compressor 31 based on the pressure fluctuation of the refrigerant flowing in the refrigerant circuit 50 by fully closing the gas opening adjustment valve 82.

[0069] As a result, the refrigeration cycle device 1 can prevent the pressure of the refrigerant flowing in other utilization units from increasing and other utilization units from being damaged by fully closing the gas opening adjustment valve 82.

[0070] (4) Modification (4-1) Modification 1A In the present embodiment, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 controls the compressor 31 based on the pressure fluctuation of the refrigerant flowing in the refrigerant circuit 50 by fully closing the gas opening adjustment valve 82.

[0071] However, when the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 may control the compressor 31 based on the state of the utilization unit 20 after closing the gas opening adjustment valve 82 completely. The state of the utilization unit 20 includes the capacity of the utilization unit 20 or the opening degree of the gas opening adjustment valve 82. For example, when the capacity of the utilization unit 20 is relatively large, if the control unit 40 closes the gas opening adjustment valve 82 completely, the pressure of the refrigerant flowing in other utilization units is likely to increase. Therefore, when the capacity of the utilization unit 20 is relatively large, the control unit 40 reduces the rotational speed of the compressor motor 31m after closing the gas opening adjustment valve 82 completely. Also, for example, when the opening degree of the gas opening adjustment valve 82 before closing it completely is relatively large, if the control unit 40 closes the gas opening adjustment valve 82 completely, the pressure of the refrigerant flowing in other utilization units is likely to increase. Therefore, when the opening degree of the gas opening adjustment valve 82 before closing it completely is relatively large, the control unit 40 reduces the rotational speed of the compressor motor 31m after closing the gas opening adjustment valve 82 completely.

[0072] Also, the state of the utilization unit 20 may include the opening degree of the utilization expansion valve 23. For example, when the opening degree of the utilization expansion valve 23 before closing the gas opening adjustment valve 82 completely is relatively large, if the control unit 40 closes the gas opening adjustment valve 82 completely, the pressure of the refrigerant flowing in other utilization units is likely to increase. Therefore, when the opening degree of the utilization expansion valve 23 before closing the gas opening adjustment valve 82 completely is relatively large, the control unit 40 reduces the rotational speed of the compressor motor 31m after closing the gas opening adjustment valve 82 completely.

[0073] As a result, the refrigeration cycle device 1 can prevent the pressure of the refrigerant flowing in other utilization units from increasing and other utilization units from being damaged by closing the gas opening adjustment valve 82 completely.

[0074] Note that when the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 may close the gas opening adjustment valve 82 completely after controlling the compressor 31 based on the state of the utilization unit 20.

[0075] (4-2) Modified Example 1B The opening degree adjustment unit 80 may be provided for each of a plurality of utilization units connected to the heat source unit 30, or may be provided for a part of the plurality of utilization units.

[0076] (4-3) Modification Example 1C The refrigeration cycle device 1 may be a multi-type air conditioning system for a building in which a plurality of utilization units connected to the heat source unit 30 can each independently perform a cooling operation and a heating operation.

[0077] (4-4) As described above, the embodiments of the present disclosure have been described. It will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure described in the claims.

[0078] <Second Embodiment> Hereinafter, the description will focus on the differences from the first embodiment.

[0079] FIG. 3 is a diagram showing the refrigerant circuit 50 of the refrigeration cycle device 1 in the present embodiment. As shown in FIG. 3, the opening degree adjustment unit 801 in the present embodiment does not have a liquid opening degree adjustment valve 81, unlike the opening degree adjustment unit 80 in the first embodiment.

[0080] When performing a cooling operation and a heating operation, the utilization expansion valve 23 also serves as the function of the liquid opening degree adjustment valve 81.

[0081] As a result, the refrigeration cycle device 1 can simplify the structure of the refrigeration cycle device 1 by using the gas opening degree adjustment valve 82 as a shut-off valve for shutting off the refrigerant leaking from the utilization unit 20.

[0082] The opening adjustment unit 801 may be provided for each of a plurality of utilization units connected to the heat source unit 30, or may be provided for a part of the plurality of utilization units. Further, as shown in FIG. 3, an opening adjustment unit 801 is provided for the utilization unit 20, and an opening adjustment unit 80a is provided for the utilization unit 20a. Different types of opening adjustment units may be provided for each of the plurality of utilization units.

[0083] As described above, the embodiments of the present disclosure have been described. It will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure described in the claims.

Explanation of reference numerals

[0084] 1 Refrigeration cycle device 20 Utilization unit (first utilization unit) 20a Utilization unit 23 Utilization expansion valve (second opening adjustment valve) 30 Heat source unit 31 Compressor 40 Control unit 50 Refrigerant circuit 56 Gas refrigerant connection pipe (first refrigerant pipe) 61 Refrigerant sensor (first sensor) 82 Gas opening adjustment valve (first opening adjustment valve)

Prior art documents

Patent documents

[0085]

Patent Document 1

Claims

1. A heat source unit (30) having a compressor (31), A plurality of utilization units (20, 20a) including a first utilization unit (20) that constitutes a refrigerant circuit (50) together with the heat source unit, A first opening degree adjustment valve (82) provided for the first utilization unit, A control unit (40), Comprising, The first utilization unit has a first sensor (61) for detecting refrigerant leakage, The control unit, Controls the first opening degree adjustment valve to adjust the evaporation temperature or condensation temperature in the first utilization unit, When the first sensor detects refrigerant leakage, the refrigerant leaking from the first utilization unit is blocked by closing the first opening degree adjustment valve completely, A refrigeration cycle device (1).

2. The first opening degree adjustment valve is provided in a first refrigerant pipe (56) on the gas side connected to the first utilization unit, When the first sensor detects refrigerant leakage, the control unit closes the first opening degree adjustment valve completely to block the refrigerant leaking from the first utilization unit through the first refrigerant pipe, The refrigeration cycle device (1) according to Claim 1.

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

4. When the first sensor detects refrigerant leakage, the control unit controls the compressor based on the pressure fluctuation of the refrigerant flowing in the refrigerant circuit by closing the first opening degree adjustment valve completely, The refrigeration cycle device (1) according to Claim 1 or 2.

5. When the first sensor detects refrigerant leakage, the control unit controls the compressor based on the state of the first utilization unit, The refrigeration cycle device (1) according to Claim 1 or 2.

6. The state of the first utilization unit includes the capacity of the first utilization unit or the opening degree of the first opening degree adjustment valve, The refrigeration cycle device (1) according to Claim 5.

7. The first utilization unit has a second opening degree adjustment valve (23) inside, The state of the first utilization unit includes the opening degree of the second opening degree adjustment valve, The refrigeration cycle device (1) according to Claim 5.

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