Refrigeration cycle device

Abstract

A problem of complication in the structure of a refrigeration cycle device is posed when a shut-off valve is provided thereto apart from an opening adjustment valve. A refrigeration cycle device (1) comprises 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 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 leakage of a refrigerant. The control unit (40) controls the gas opening adjustment valve (82) to adjust the evaporating temperature or condensing temperature in the utilization unit (20). When leakage of the refrigerant is detected by the refrigerant sensor (61), the control unit (40) fully closes the gas opening adjustment valve (82) to thereby shut off the refrigerant that is leaking from the utilization unit (20).

Description

Refrigeration cycle equipment

[0001] This relates to a refrigeration cycle device.

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

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

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

[0005] In the refrigeration cycle apparatus of the first aspect, when the first sensor detects a refrigerant leak, the control unit shuts off the refrigerant leaking from the first usage unit by fully closing the first degree of opening adjustment valve. As a result, the refrigeration cycle apparatus can simplify its structure by using the first degree of opening adjustment valve as a shutoff valve that shuts off the refrigerant leaking from the first usage unit.

[0006] A refrigeration cycle apparatus according to a second aspect is the refrigeration cycle apparatus according to the first aspect, wherein the first degree of opening adjustment valve is provided in a first refrigerant pipe on a gas side connected to a first usage unit, and when the first sensor detects a refrigerant leak, the control unit fully closes the first degree of opening adjustment valve to block refrigerant leaking from the first usage unit through the first refrigerant pipe.

[0007] A refrigeration cycle device of a third aspect is a refrigeration cycle device of the first or second aspect, in which the control unit controls the first opening adjustment valve so that the evaporation temperature or condensation temperature in the first usage unit becomes a target evaporation temperature or target condensation temperature.

[0008] A refrigeration cycle device of a fourth aspect is a refrigeration cycle device of any one of the first aspect to the third aspect, wherein when the first sensor detects a refrigerant leak, the control unit controls the compressor based on a pressure fluctuation of the refrigerant flowing in the refrigerant circuit caused by fully closing the first opening adjustment valve.

[0009] With this configuration, the refrigeration cycle apparatus of the fourth aspect can prevent the pressure of the refrigerant flowing in the other utilization units from increasing and damaging the other utilization units.

[0010] A refrigeration cycle device of a fifth aspect is a refrigeration cycle device of any one of the first aspect to the third aspect, wherein the control unit controls the compressor based on the state of the first usage unit when the first sensor detects a refrigerant leak.

[0011] With such a configuration, the refrigeration cycle apparatus of the fifth aspect can prevent the pressure of the refrigerant flowing in the other utilization units from increasing and damaging the other utilization units.

[0012] A refrigeration cycle apparatus according to a sixth aspect is the refrigeration cycle apparatus according to the fifth aspect, wherein the state of the first usage unit includes the capacity of the first usage unit or the degree of opening of the first degree-of-opening adjustment valve.

[0013] A refrigeration cycle apparatus according to a seventh aspect is the refrigeration cycle apparatus according to the fifth aspect, wherein the first utilization unit has a second degree of opening adjustment valve therein, and the state of the first utilization unit includes the degree of opening of the second degree of opening adjustment valve.

[0014] It is a diagram showing a refrigerant circuit of the refrigeration cycle device in 1st embodiment. It is a control block diagram of the refrigeration cycle device in 1st embodiment. It is a diagram showing a refrigerant circuit of the refrigeration cycle device in 2nd embodiment.

[0015] First Embodiment (1) Overall Configuration The refrigeration cycle apparatus 1 forms a vapor compression refrigeration cycle and conditions the air in a target space. In this embodiment, the refrigeration cycle apparatus 1 is a so-called multi-type air conditioning system for a building. FIG. 1 is a diagram showing a refrigerant circuit 50 of the refrigeration cycle apparatus 1 in this embodiment. As shown in FIG. 1, the refrigeration cycle apparatus 1 mainly includes a heat source unit 30, multiple utilization units 20, 20a, opening adjustment units 80, 80a, and a controller 40. The heat source unit 30 and the multiple utilization units 20, 20a are connected by a liquid refrigerant communication pipe 51 and a gas refrigerant communication pipe 52 to form the refrigerant circuit 50. The heat source unit 30, the multiple utilization units 20, 20a, and the opening adjustment units 80, 80a are communicatively connected via communication lines (not shown). While FIG. 1 illustrates two utilization units 20, 20a as an example, any number of utilization units may be connected to the heat source unit 30.

[0016] (2) Detailed Configuration (2-1) Usage Unit Since the usage units 20 and 20a have basically the same structure, the usage unit 20 (first usage unit) will be described below.

[0017] The utilization unit 20 is installed in a target space within the building in which the refrigeration cycle apparatus 1 is installed. The utilization unit 20 may be, for example, a ceiling-embedded unit, a ceiling-suspended unit, or a floor-standing unit. 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 (second opening adjustment valve), a utilization control unit 29, a refrigerant sensor 61 (first sensor), and a saturation temperature sensor 64. The utilization unit 20 also includes a liquid refrigerant pipe 57 connecting the liquid side end of the utilization heat exchanger 21 to a liquid refrigerant communication pipe 55 branched off from the liquid refrigerant communication pipe 51 toward the utilization unit 20. The utilization unit 20 also includes a gas refrigerant pipe 58 connecting the gas side end of the utilization heat exchanger 21 to a gas refrigerant communication pipe 56 branched off from the gas refrigerant communication pipe 52 toward the utilization unit 20. The liquid refrigerant pipe 57 and the gas refrigerant pipe 58 are provided within the utilization unit 20.

[0018] (2-1-1) Utilization Heat Exchanger The utilization heat exchanger 21 performs heat exchange between the refrigerant flowing inside 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) Usage Fan The usage fan 22 supplies air from the target space to the usage heat exchanger 21. The usage fan 22 is, for example, a centrifugal fan such as a turbo fan or a sirocco fan. As shown in FIG. 1, the usage fan 22 is driven by a usage fan motor 22m. The rotation speed of the usage fan motor 22m can be controlled by an inverter.

[0020] (2-1-3) Utility Expansion Valve The utility expansion valve 23 is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 57. The utility expansion valve 23 is provided in the liquid refrigerant pipe 57. The utility expansion valve 23 is an electrically operated 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. During cooling operation, the saturation temperature sensor 64 measures the evaporation temperature of the refrigerant flowing through the utilization heat exchanger 21. During heating operation, the saturation temperature sensor 64 measures the condensation temperature of the refrigerant flowing through the utilization heat exchanger 21. The saturation temperature sensor 64 is provided in the utilization heat exchanger 21.

[0023] (2-1-5) Usage Control Unit The usage control unit 29 is connected to be able to communicate with various devices of the usage unit 20, including the usage expansion valve 23, the usage fan motor 22m, the refrigerant sensor 61, and the saturation temperature sensor 64.

[0024] The usage control unit 29 has a control and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU or GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out programs stored in the storage device and performs predetermined arithmetic processing in accordance with the programs, thereby controlling the operation of various devices in the usage unit 20. The control and arithmetic device can also write arithmetic results to the storage device and read out information stored in the storage device in accordance with the programs.

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

[0026] The usage control unit 29 exchanges control signals, measurement signals, signals related to various settings, and the like 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 communication lines. The usage control unit 29, the heat source control unit 39, and the opening control unit 89 work together to function as the control unit 40.

[0027] (2-2) Heat Source Unit The heat source unit 30 is installed on the roof or the like of the building in which the refrigeration cycle apparatus 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. The heat source unit 30 also includes a suction pipe 54a, a discharge pipe 54b, gas refrigerant pipes 54c and 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. The accumulator 35 is provided on 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 communication pipe 51. The liquid refrigerant pipe 54d is provided with the heat source expansion valve 34. A liquid shut-off valve 37 is provided at the connection between the liquid refrigerant pipe 54d and the liquid refrigerant communication pipe 51. The gas refrigerant pipe 54e connects the flow path switching valve 32 and the gas refrigerant communication pipe 52. A gas shut-off valve 38 is provided at the connection between the gas refrigerant pipe 54e and the gas refrigerant communication pipe 52. The liquid shutoff valve 37 and the gas shutoff valve 38 are valves that are manually opened and closed.

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

[0030] The compressor 31 is, for example, a rotary type or scroll type volumetric compressor. The compression mechanism of the compressor 31 is driven by a compressor motor 31m. The rotation 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. In the first state, the flow path switching valve 32 connects the suction pipe 54a to the gas refrigerant pipe 54e and the discharge pipe 54b to the gas refrigerant pipe 54c, as shown by the solid lines in the flow path switching valve 32 in Fig. 1. In the second state, the flow path switching valve 32 connects the suction pipe 54a to the gas refrigerant pipe 54c and the discharge pipe 54b to the gas refrigerant pipe 54e, as shown by the dashed lines in the flow path switching valve 32 in Fig. 1.

[0032] During 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 then 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 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, utilization expansion valve 23, heat source expansion valve 34, and heat source heat exchanger 33, and then 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 exchanges heat 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 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 Figure 1, the heat source expansion valve 34 is provided in the liquid refrigerant pipe 54d. The heat source expansion valve 34 is an electrically operated valve whose opening degree can be adjusted.

[0036] (2-2-5) Accumulator The accumulator 35 is a container having a gas-liquid separation function that separates the refrigerant that flows in into the accumulator 35 into gas refrigerant and liquid refrigerant. As shown in Fig. 1, the accumulator 35 is provided in the suction pipe 54a. The refrigerant that flows into the accumulator 35 is separated into gas refrigerant and liquid refrigerant, and the gas refrigerant that collects 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) Sensors 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 a refrigerant pressure that corresponds to the evaporation pressure during 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 on the discharge pipe 54b. The discharge pressure is a refrigerant pressure that corresponds to the condensation pressure during heating operation.

[0040] (2-2-8) Heat Source Control Unit The heat source control unit 39 is connected to be able to communicate with 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 and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU or GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out programs stored in the storage device and performs predetermined arithmetic processing in accordance with the programs, thereby controlling the operation of various devices in the heat source unit 30. The control and arithmetic device can also write calculation results to the storage device and read out information stored in the storage device in accordance with the programs.

[0042] The heat source control unit 39 exchanges control signals, measurement signals, signals related to various settings, and the like via communication lines with the usage control unit 29 of the usage unit 20 and the opening control unit 89 of the opening adjustment unit 80. The heat source control unit 39, usage control unit 29, and opening control unit 89 work together to function as the control unit 40.

[0043] (2-3) Opening Adjustment Unit The opening adjustment units 80 and 80a are basically similar in structure, so only the opening adjustment unit 80 will be described below.

[0044] 1, the opening adjustment unit 80 is provided for the utilization unit 20. The opening adjustment unit 80 has a liquid opening adjustment valve 81, a gas opening adjustment valve 82, and an opening control unit 89.

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

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

[0047] The liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82 are motor-operated valves with adjustable apertures. Furthermore, when the liquid aperture adjustment valve 81 is fully closed, the liquid aperture adjustment valve 81 functions as a shutoff valve that shuts off the refrigerant flowing through the liquid refrigerant communication pipe 55. When the gas aperture adjustment valve 82 is fully closed, the gas aperture adjustment valve 82 functions as a shutoff valve that shuts off the refrigerant flowing through the gas refrigerant communication pipe 56.

[0048] The opening control unit 89 is connected to be able to communicate with various devices of the opening adjustment unit 80 , including the liquid opening adjustment valve 81 and the gas opening adjustment valve 82 .

[0049] The opening control unit 89 has a control and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU or a GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs predetermined arithmetic processing in accordance with the program, thereby controlling the operation of various devices in the heat source unit 30. The control and arithmetic device can also write calculation results to the storage device and read out information stored in the storage device in accordance with the program.

[0050] The opening control unit 89 exchanges control signals, measurement signals, signals related to various settings, and the like via communication lines with the usage control unit 29 of the usage unit 20 and the heat source control unit 39 of the heat source unit 30. The opening control unit 89, usage control unit 29, and heat source control unit 39 work together to function as the control unit 40.

[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 apparatus 1 by causing the control and arithmetic devices of the usage control unit 29, the heat source control unit 39, and the opening control unit 89 to execute programs stored in their respective storage devices.

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

[0053] The control unit 40 mainly performs cooling operation and heating operation, and also mainly has a function of preventing refrigerant leakage.

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

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

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

[0057] When the compressor 31 is started, low-pressure gas refrigerant is drawn into the compressor 31 and compressed by the compressor 31 to become 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, where it exchanges heat with the air around the heat source unit 30 supplied by the heat-source fan 36, condensing to become 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 reduced in pressure by the utilization expansion valve 23 to near the suction pressure of the compressor 31, becoming a two-phase gas-liquid refrigerant, which is sent to the utilization heat exchanger 21. In the utilization heat exchanger 21, the two-phase gas-liquid refrigerant exchanges heat with the air in the target space supplied to the utilization heat exchanger 21 by the utilization fan 22, evaporating to become low-pressure gas refrigerant. The low-pressure gas refrigerant is sent to the heat source unit 30 via the gas refrigerant communication pipe 52, and flows into the accumulator 35 via the flow path switching valve 32. The low-pressure gas refrigerant that has flowed into the accumulator 35 is again sucked into the compressor 31. The temperature of the air supplied to the utilization heat exchanger 21 is lowered by heat exchange with the refrigerant flowing through the utilization heat exchanger 21, and the air cooled by the utilization heat exchanger 21 is blown out into the target space.

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

[0059] The control unit 40 then controls the liquid aperture adjustment valve 81, the gas aperture adjustment valve 82, the compressor motor 31 m, the utilization heat expansion valve 23, etc. so that the condensing temperature measured by the saturation temperature sensor 64 becomes the target condensing temperature. In particular, the control unit 40 controls the gas aperture adjustment valve 82 to adjust the condensing temperature of the refrigerant flowing through the utilization heat exchanger 21. For example, the control unit 40 lowers the condensing temperature of the refrigerant flowing through the utilization heat exchanger 21 by reducing the aperture of the gas aperture adjustment valve 82. The target condensing temperature is set, for example, according to a set temperature received from an operation remote control. The control unit 40 also controls the aperture 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 drawn into the compressor 31 and compressed by the compressor 31 to become high-pressure gas refrigerant. The high-pressure gas refrigerant is sent to the utilization heat exchanger 21 via the flow path switching valve 32, where it exchanges heat with air in the target space and is supplied to the utilization heat exchanger 21 by the utilization fan 22, condensing and becoming high-pressure liquid refrigerant. The temperature of the air supplied to the utilization heat exchanger 21 increases through heat exchange with the refrigerant flowing through the utilization heat exchanger 21, and the air heated by the utilization heat exchanger 21 is blown into the target space. The high-pressure liquid refrigerant that has passed through the utilization heat exchanger 21 is decompressed in the utilization expansion valve 23. The decompressed 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 decompressed in the heat source expansion valve 34 to near the suction pressure of the compressor 31, becoming gas-liquid two-phase refrigerant and flowing into the heat source heat exchanger 33. The low-pressure gas-liquid two-phase refrigerant that has flowed into the heat source heat exchanger 33 exchanges heat with the air around the heat source unit 30 that is 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 that has flowed into the accumulator 35 is again sucked into the compressor 31.

[0061] (2-4-3) Refrigerant Leakage Prevention Function When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 fully closes the liquid aperture adjustment valve 81 to stop refrigerant leaking from the user unit 20 through the liquid refrigerant communication pipe 55. When the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 fully closes the gas aperture adjustment valve 82 to stop refrigerant leaking from the user unit 20 through the gas refrigerant communication pipe 56. The control unit 40 may further fully close the user expansion valve 23.

[0062] Fully closing the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82 increases the pressure of the refrigerant flowing in other utilization units (e.g., utilization unit 20a), which could damage the other utilization units. Therefore, 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 caused by fully closing the gas aperture adjustment valve 82. For example, when the measurement value of the suction pressure sensor 68 increases by fully closing the gas aperture adjustment valve 82, the control unit 40 reduces the rotation speed of the compressor motor 31m.

[0063] (3) Features (3-1) Conventionally, there is a technology for controlling the evaporation temperature or condensation temperature of a utilization unit by controlling an aperture adjustment valve provided in the utilization unit. In case of a refrigerant leak within the utilization unit, it is desirable to provide a shutoff valve for the utilization unit to shut off the refrigerant leakage. However, providing a shutoff valve separately from the aperture adjustment valve poses a problem in that the structure of the refrigeration cycle device becomes complicated.

[0064] The refrigeration cycle apparatus 1 of this embodiment includes a heat source unit 30, a plurality of utilization units 20, 20a, a gas degree of aperture adjustment valve 82, and a control unit 40. The heat source unit 30 has a compressor 31. The plurality of utilization units 20, 20a, together with the heat source unit 30, constitute a refrigerant circuit 50. The plurality of utilization units 20, 20a include a utilization unit 20. The gas degree of aperture adjustment valve 82 is provided for the utilization unit 20. The utilization unit 20 has a refrigerant sensor 61. The refrigerant sensor 61 detects refrigerant leakage. The control unit 40 controls the gas degree of aperture adjustment 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 fully closes the gas degree of aperture adjustment valve 82 to block refrigerant leaking from the utilization unit 20.

[0065] In the refrigeration cycle apparatus 1, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 fully closes the gas degree of opening adjustment valve 82 to shut off the refrigerant leaking from the utilization unit 20. As a result, the refrigeration cycle apparatus 1 uses the gas degree of opening adjustment valve 82 as a shutoff valve that shuts off the refrigerant leaking from the utilization unit 20, thereby simplifying the structure of the refrigeration cycle apparatus 1.

[0066] (3-2) In the refrigeration cycle apparatus 1, the gas aperture 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 fully closes the gas aperture adjustment valve 82 to block the refrigerant leaking from the utilization unit 20 through the gas refrigerant communication pipe 56.

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

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

[0070] (4) Modifications (4-1) Modification 1A In this 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 caused by fully closing the gas opening adjustment valve 82.

[0071] However, if the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 may fully close the gas aperture adjustment valve 82 and then control the compressor 31 based on the state of the utilization unit 20. The state of the utilization unit 20 includes the capacity of the utilization unit 20 or the opening degree of the gas aperture adjustment valve 82. For example, if the capacity of the utilization unit 20 is relatively large, the control unit 40 fully closing the gas aperture adjustment valve 82 is likely to increase the pressure of the refrigerant flowing through other utilization units. Therefore, if the capacity of the utilization unit 20 is relatively large, the control unit 40 fully closes the gas aperture adjustment valve 82 and then reduces the rotation speed of the compressor motor 31m. Also, for example, if the opening degree of the gas aperture adjustment valve 82 before fully closing it is relatively large, the control unit 40 fully closing the gas aperture adjustment valve 82 is likely to increase the pressure of the refrigerant flowing through other utilization units. Therefore, if the opening of the gas degree of opening adjustment valve 82 before it is fully closed is relatively large, the control unit 40 fully closes the gas degree of opening adjustment valve 82 and then reduces the rotation speed of the compressor motor 31m.

[0072] The state of the utilization unit 20 may also include the opening degree of the utilization expansion valve 23. For example, if the opening degree of the utilization expansion valve 23 before the gas opening degree adjustment valve 82 is fully closed is relatively large, there is a high possibility that the pressure of the refrigerant flowing in the other utilization units will increase when the control unit 40 fully closes the gas opening degree adjustment valve 82. Therefore, if the opening degree of the utilization expansion valve 23 before the gas opening degree adjustment valve 82 is relatively large, the control unit 40 fully closes the gas opening degree adjustment valve 82 and then reduces the rotation speed of the compressor motor 31m.

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

[0074] In addition, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 may control the compressor 31 based on the state of the utilization unit 20, and then fully close the gas opening adjustment valve 82.

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

[0076] (4-3) Modification 1C The refrigeration cycle apparatus 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 independently perform cooling operation and heating operation.

[0077] (4-4) 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.

[0078] Second Embodiment The following description will focus on the differences from the first embodiment.

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

[0080] When performing cooling operation and heating operation, the utilization expansion valve 23 also functions as the liquid opening adjustment valve 81 .

[0081] As a result, the refrigeration cycle apparatus 1 uses the gas degree of opening adjustment valve 82 as a shutoff valve that shuts off refrigerant leaking from the utilization unit 20, thereby simplifying the structure of the refrigeration cycle apparatus 1.

[0082] The opening degree adjustment unit 801 may be provided for each of the multiple usage units connected to the heat source unit 30, or may be provided for some of the multiple usage units. Also, as shown in Fig. 3, different types of opening degree adjustment units may be provided for each of the multiple usage units, such as providing an opening degree adjustment unit 801 for usage unit 20 and an opening degree adjustment unit 80a for usage unit 20a.

[0083] 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.

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

[0085] Japanese Patent Application Laid-Open No. 2008-281304

Claims

1. A refrigeration cycle device (1), comprising: a heat source unit (30) having a compressor (31); a plurality of utilization units (20, 20a) including a first utilization unit (20) which constitute a refrigerant circuit (50) together with the heat source unit; a first opening adjustment valve (82) provided for the first utilization unit; and a control unit (40), wherein the first utilization unit has a first sensor (61) which detects refrigerant leakage, and the control unit controls the first opening adjustment valve to adjust an evaporation temperature or a condensation temperature in the first utilization unit, and when the first sensor detects refrigerant leakage, fully closes the first opening adjustment valve to block refrigerant leaking from the first utilization unit.

2. The refrigeration cycle device (1) of claim 1, wherein the first degree of opening adjustment valve is provided in a first refrigerant piping (56) on the gas side connected to the first usage unit, and when the first sensor detects a refrigerant leak, the control unit fully closes the first degree of opening adjustment valve to block the refrigerant leaking from the first usage unit through the first refrigerant piping.

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

4. A refrigeration cycle device (1) as described in any one of claims 1 to 3, wherein when the first sensor detects a refrigerant leak, the control unit controls the compressor based on a pressure fluctuation of the refrigerant flowing in the refrigerant circuit caused by fully closing the first opening adjustment valve.

5. The refrigeration cycle device (1) according to any one of claims 1 to 3, wherein the control unit controls the compressor based on a state of the first utilization unit when the first sensor detects a refrigerant leak.

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

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

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