WO2025070019A1 - Refrigeration cycle device - Google Patents

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

　Regarding refrigeration cycle equipment.

As shown in Patent Document 1 (JP Patent Publication 2008-281304), there is a technology that controls the opening adjustment valve provided in the utilization unit to control the evaporation temperature or condensation temperature in the utilization unit.

In the event that refrigerant leaks within the utilization unit, it is desirable to provide a shutoff valve to stop refrigerant leakage from the utilization unit. However, providing a shutoff valve in addition to the opening adjustment valve creates the problem that the structure of the refrigeration cycle device becomes complicated.

The refrigeration cycle device of the 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.

In the refrigeration cycle device 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 device 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.

The refrigeration cycle device of the second aspect is the refrigeration cycle device of the first aspect, in which the first opening adjustment valve is provided on the gas side of the first refrigerant piping connected to the first usage unit. When the first sensor detects a refrigerant leak, the control unit fully closes the first opening adjustment valve to block the refrigerant leaking from the first usage unit through the first refrigerant piping.

The refrigeration cycle device of the third aspect is the 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 utilization unit becomes the target evaporation temperature or target condensation temperature.

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

The refrigeration cycle device of the fourth aspect, with such a configuration, can prevent the pressure of the refrigerant flowing in the other utilization units from increasing and damaging the other utilization units.

The refrigeration cycle device of the fifth aspect is the refrigeration cycle device of any one of the first aspect to the third aspect, in which the control unit controls the compressor based on the state of the first utilization unit when the first sensor detects a refrigerant leak.

The refrigeration cycle device of the fifth aspect, with such a configuration, can prevent the pressure of the refrigerant flowing in the other utilization units from increasing and damaging the other utilization units.

The refrigeration cycle device of the sixth aspect is the refrigeration cycle device of the fifth aspect, in which the state of the first utilization unit includes the capacity of the first utilization unit or the opening of the first opening adjustment valve.

The seventh aspect of the refrigeration cycle device is the fifth aspect of the refrigeration cycle device, in which the first utilization unit has a second opening adjustment valve therein. The state of the first utilization unit includes the opening of the second opening adjustment valve.

1 is a diagram showing a refrigerant circuit of a refrigeration cycle device in a first embodiment. FIG. 2 is a control block diagram of the refrigeration cycle device according to the first embodiment. FIG. 6 is a diagram showing a refrigerant circuit of a refrigeration cycle device according to a second embodiment.

First Embodiment
(1) Overall Configuration The refrigeration cycle device 1 constitutes a vapor compression refrigeration cycle and performs air conditioning of a 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 a refrigerant circuit 50 of the refrigeration cycle device 1 in this embodiment. As shown in FIG. 1, the refrigeration cycle device 1 mainly has 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 a refrigerant circuit 50. The heat source unit 30, the plurality of utilization units 20, 20a, and the opening degree adjustment units 80, 80a are connected to each other so as to be able to communicate with each other by a communication line (not shown). In FIG. 1, two utilization units 20, 20a are shown as an example, but the number of utilization units connected to the heat source unit 30 is arbitrary.

(2) Detailed Configuration (2-1) Utilization Unit Since the utilization units 20, 20a have basically the same structure, the utilization unit 20 (first utilization unit) will be described below.

The utilization unit 20 is installed in a target space in the building in which the refrigeration cycle device 1 is installed. The utilization unit 20 is, 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 that connects the liquid side end of the utilization heat exchanger 21 to a liquid refrigerant connection pipe 55 in which the liquid refrigerant connection pipe 51 branches off to the utilization unit 20 side. The utilization unit 20 includes a gas refrigerant pipe 58 that connects the gas side end of the utilization heat exchanger 21 to a gas refrigerant connection pipe 56 in which the gas refrigerant connection pipe 52 branches off to the utilization unit 20 side. The liquid refrigerant pipe 57 and the gas refrigerant pipe 58 are provided in the utilization unit 20.

(2-1-1) Utilization Heat Exchanger The utilization heat exchanger 21 exchanges heat 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.

(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.

(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.

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

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

(2-1-5) Usage Control Unit The usage control unit 29 is connected to be able to communicate with various devices included in 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.

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 and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control and arithmetic device controls the operation of various devices in the usage unit 20 by reading out a program stored in the storage device and performing a predetermined arithmetic process in accordance with the program. The control and arithmetic device can also write the results of calculations to the storage device and read out information stored in the storage device in accordance with the program.

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.

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, heat source control unit 39, and opening control unit 89 work together to function as the control unit 40.

(2-2) Heat Source Unit The heat source unit 30 is installed on the roof 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 stop valve 37, a gas stop 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.

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 connection pipe 51. The liquid refrigerant pipe 54d is provided with a heat source expansion valve 34. A liquid shutoff valve 37 is provided at the connection 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 shutoff valve 38 is provided at the connection between the gas refrigerant pipe 54e and the gas refrigerant connection pipe 52. The liquid shutoff valve 37 and the gas shutoff valve 38 are valves that are manually opened and closed.

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

Compressor 31 is, for example, a volumetric compressor such as a rotary type or scroll type. The compression mechanism of compressor 31 is driven by compressor motor 31m. The rotation speed of compressor motor 31m can be controlled by an inverter.

(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 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 dashed lines in the flow path switching valve 32 in Fig. 1.

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.

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.

(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 type heat exchanger having a plurality of heat transfer fins and a plurality of heat transfer tubes.

(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 electrically operated valve whose opening degree can be adjusted.

(2-2-5) Accumulator The accumulator 35 is a container having a gas-liquid separation function that separates the refrigerant that flows in 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 that flows in the accumulator 35 is separated into a gas refrigerant and a liquid refrigerant, and the gas refrigerant that collects in the upper space flows into the compressor 31.

(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.

(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.

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 that corresponds to the condensation pressure during heating operation.

(2-2-8) Heat Source Control Unit The heat source control unit 39 is communicatively 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.

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 controls the operation of various devices in the heat source unit 30 by reading out a program stored in the storage device and performing a predetermined arithmetic process in accordance with the program. The control arithmetic device can also write the results of calculations to the storage device and read out information stored in the storage device in accordance with the program.

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

(2-3) Opening Adjustment Unit Since the opening adjustment units 80, 80a are basically similar in structure, only the opening adjustment unit 80 will be described below.

As shown in FIG. 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.

The liquid opening adjustment valve 81 is provided in the liquid refrigerant connection 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 connection pipe 55 connected to the utilization unit 20.

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.

The liquid opening adjustment valve 81 and the gas opening adjustment valve 82 are motorized valves whose opening can be adjusted. Furthermore, when the liquid opening adjustment valve 81 is fully closed, the liquid opening adjustment valve 81 functions as a shutoff valve that shuts off the refrigerant flowing through the liquid refrigerant connection pipe 55. When the gas opening adjustment valve 82 is fully closed, the gas opening adjustment valve 82 functions as a shutoff valve that shuts off the refrigerant flowing through the gas refrigerant connection pipe 56.

The opening control unit 89 is connected 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.

The opening control unit 89 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 a program stored in the storage device and performs a predetermined arithmetic process in accordance with the program, thereby controlling the operation of various devices in the heat source unit 30. The control arithmetic device can also write the results of calculations to the storage device and read out information stored in the storage device in accordance with the program.

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

(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 the respective storage devices.

FIG. 2 is a control block diagram of the refrigeration cycle apparatus 1 in this embodiment. As shown in FIG. 2, the control unit 40 is communicatively 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 opening adjustment valve 81, and gas opening adjustment valve 82. The control unit 40 controls the operation of various devices of the refrigeration cycle apparatus 1 based on control signals received from the operation remote control via the utilization unit 20, measurement signals from various sensors, etc.

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

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

Then, the control unit 40 fully opens the heat source expansion valve 34 and 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 evaporation temperature measured by the saturation temperature sensor 64 becomes the target evaporation temperature. In particular, the control unit 40 controls the gas opening 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 opening of the gas opening adjustment valve 82. The target evaporation temperature is set, for example, according to the set temperature received from the operation remote control.

As described above, the operation of various devices is controlled so that refrigerant flows through the refrigerant circuit 50 during cooling operation as follows:

When the compressor 31 is started, low-pressure gas refrigerant is sucked 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, condenses, and becomes 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 to near the suction pressure of the compressor 31 in the utilization expansion valve 23, becomes a two-phase gas-liquid refrigerant, and is sent to 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 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 communication pipe 52, and flows into the accumulator 35 via the flow path switching valve 32. The low-pressure gas refrigerant that flows into the accumulator 35 is again sucked into the compressor 31. The temperature of the air supplied to the utilization heat exchanger 21 is reduced 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.

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

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 condensing temperature measured by the saturation temperature sensor 64 becomes the target condensing temperature. In particular, the control unit 40 controls the gas opening 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 decreasing the opening of the gas opening adjustment valve 82. The target condensing temperature is set, for example, according to the set temperature received from the operation remote control. In addition, 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.

When the compressor 31 is started, low-pressure gas refrigerant is sucked 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, and condenses through heat exchange with the air in the target space supplied to the utilization heat exchanger 21 by the utilization fan 22, 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 out into the target space. The high-pressure liquid refrigerant that has passed through the utilization heat exchanger 21 is depressurized in 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 to near the suction pressure of the compressor 31 in the heat source expansion valve 34, becomes a gas-liquid two-phase refrigerant, and flows into the heat source heat exchanger 33. The low-pressure gas-liquid two-phase refrigerant that flows 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, evaporating and becoming a 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 flows into the accumulator 35 is again sucked into the compressor 31.

(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 shut off refrigerant leaking from the utilization 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 shut off refrigerant leaking from the utilization unit 20 through the gas refrigerant communication pipe 56. The control unit 40 may further fully close the utilization expansion valve 23.

By fully closing the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82, the pressure of the refrigerant flowing in other utilization units (e.g., utilization unit 20a) increases, which may 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.

(3) Features (3-1)
Conventionally, there is a technique for controlling an opening adjustment valve provided for a utilization unit to control the evaporation temperature or condensation temperature in the utilization unit. In case of a refrigerant leak in 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 opening adjustment valve causes a problem that the structure of the refrigeration cycle device becomes complicated.

The refrigeration cycle device 1 of this embodiment includes a heat source unit 30, a plurality of utilization units 20, 20a, a gas opening adjustment valve 82, and a control unit 40. The heat source unit 30 has a compressor 31. The plurality of utilization units 20, 20a constitute a refrigerant circuit 50 together with the heat source unit 30. The plurality of utilization units 20, 20a include a utilization unit 20. The gas opening 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 opening 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 opening adjustment valve 82 to block refrigerant leaking from the utilization unit 20.

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 its structure by using the gas opening adjustment valve 82 as a shutoff valve that shuts off the refrigerant leaking from the utilization unit 20.

(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 shut off the refrigerant leaking from the utilization unit 20 through the gas refrigerant communication pipe 56.

(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.

(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.

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 through the other utilization units from increasing and damaging the other utilization units.

(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.

However, when the refrigerant sensor 61 detects a refrigerant leak, the control unit 40 may fully close the gas opening 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 of the gas opening adjustment valve 82. For example, when the capacity of the utilization unit 20 is relatively large, the control unit 40 fully closes the gas opening adjustment valve 82, which is likely to increase the pressure of the refrigerant flowing in the other utilization units. Therefore, when the capacity of the utilization unit 20 is relatively large, the control unit 40 fully closes the gas opening adjustment valve 82 and then reduces the rotation speed of the compressor motor 31m. Also, for example, when the opening of the gas opening adjustment valve 82 before fully closing it is relatively large, the control unit 40 fully closes the gas opening adjustment valve 82, which is likely to increase the pressure of the refrigerant flowing in the other utilization units. Therefore, if the opening of the gas opening adjustment valve 82 before it is fully closed is relatively large, the control unit 40 reduces the rotation speed of the compressor motor 31m after fully closing the gas opening adjustment valve 82.

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.

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 through the other utilization units from increasing and damaging the other utilization units.

If 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.

(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.

(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.

(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 described in the claims.

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

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

When performing cooling and heating operations, the utilization expansion valve 23 also functions as the liquid opening adjustment valve 81.

As a result, the structure of the refrigeration cycle device 1 can be simplified by using the gas opening adjustment valve 82 as a shutoff valve that shuts off refrigerant leaking from the utilization unit 20.

The opening adjustment unit 801 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. Also, as shown in FIG. 3, a different type of opening adjustment unit may be provided for each of the multiple utilization units, such as providing an opening adjustment unit 801 for utilization unit 20 and an opening adjustment unit 80a for utilization unit 20a.

Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure as set forth in the claims.

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)

JP 2008-281304 A

Claims (7)

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;
A control unit (40);
Equipped with
The first utilization unit has a first sensor (61) for detecting leakage of a refrigerant,
The control unit is
Controlling the first degree of opening adjustment valve to adjust an evaporation temperature or a condensation temperature in the first utilization unit;
When the first sensor detects a refrigerant leak, the first degree of opening adjustment valve is fully closed to block the refrigerant leaking from the first utilization unit.
Refrigeration cycle device (1). the first opening adjustment valve is provided in a first refrigerant pipe (56) on a gas side connected to the first utilization unit,
When the first sensor detects a leakage of the refrigerant, 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.
A refrigeration cycle device (1) as claimed in claim 1. the control unit controls the first degree-of-opening adjustment valve so that an evaporation temperature or a condensation temperature in the first utilization unit becomes a target evaporation temperature or a target condensation temperature.
A refrigeration cycle device (1) according to claim 1 or 2. 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 degree of opening adjustment valve when the first sensor detects a leakage of the refrigerant.
A refrigeration cycle device (1) according to any one of claims 1 to 3. the control unit controls the compressor based on a state of the first usage unit when the first sensor detects a refrigerant leak.
A refrigeration cycle device (1) according to any one of claims 1 to 3. 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.
A refrigeration cycle device (1) according to claim 5. The first utilization unit has a second opening adjustment valve (23) therein,
the state of the first utilization unit includes the opening degree of the second opening degree adjustment valve;
A refrigeration cycle device (1) according to claim 5.

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