Refrigeration cycle device

Abstract

To solve the problem in which, in the case where a plurality of utilization units having different design pressures is connected to a heat source unit, a pressure of a refrigerant flowing in the plurality of utilization units becomes the pressure according to the utilization unit whose design pressure is the smallest, and the utilization units whose design pressure is relatively high cannot sufficiently exert their capacity.SOLUTION: A refrigeration cycle device 1 includes a heat source unit 30, a plurality of utilization units 20, 20a, liquid opening adjustment valves 81, 81a, gas opening adjustment valves 82, 82a, and a control part 40. The liquid opening adjustment valve 81 is provided at a liquid refrigerant communication pipeline 55 on the high pressure side connected to the utilization unit 20 during a cooling operation. The gas opening adjustment valve 82 is provided at a gas refrigerant communication pipeline 56 on the high pressure side connected to the utilization unit 20 during a heating operation. The control part 40 controls the liquid opening adjustment valve 81 or the gas opening adjustment valve 82 based on the design pressure of the utilization unit 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This relates to a refrigeration cycle device. [Background technology]

[0002] As disclosed in Patent Document 1 (JP 2023-030403 A), there is a technique for controlling the pressure of the refrigerant flowing inside a utilization unit by using a pressure sensor provided in a heat source unit. Summary of the Invention [Problem to be solved by the invention]

[0003] When the pressure of the refrigerant flowing through the utilization unit is controlled using a pressure sensor provided in the heat source unit, the pressure of the refrigerant flowing through the multiple utilization units connected to the heat source unit is set to a uniform value. Therefore, when multiple utilization units with different design pressures are connected to the heat source unit, the pressure of the refrigerant flowing through the multiple utilization units is set to a value that matches the utilization unit with the lowest design pressure, which causes a problem that utilization units with a relatively high design pressure cannot fully demonstrate their capabilities. [Means for solving the problem]

[0004] A refrigeration cycle apparatus according to 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 plurality of utilization units configure 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 in a first refrigerant pipe on the high pressure side connected to the first utilization unit. The control unit controls the first degree of opening adjustment valve based on a first design pressure of the first utilization unit.

[0005] In the refrigeration cycle apparatus of the first aspect, the control unit controls the first degree of opening adjustment valve provided in the first refrigerant pipe on the high pressure side based on the first design pressure of the first utilization unit. Therefore, the refrigeration cycle apparatus can control the pressure of the refrigerant flowing in each of the utilization units based on the design pressure. As a result, even when multiple utilization units with different design pressures are connected to the heat source unit, each utilization unit can fully demonstrate its capacity.

[0006] A refrigeration cycle apparatus according to a second aspect is the refrigeration cycle apparatus according to the first aspect, wherein the control unit acquires first equipment information from a first utilization unit, and controls the first degree-of-opening adjustment valve based on a first design pressure included in the first equipment information.

[0007] With such a configuration, the refrigeration cycle apparatus of the second aspect can control the pressure of the refrigerant flowing inside each utilization unit, for each utilization unit, based on information acquired from the utilization unit.

[0008] A refrigeration cycle apparatus according to a third aspect is the refrigeration cycle apparatus according to the second aspect, wherein the control unit stores the acquired first equipment information and controls the first degree-of-opening adjustment valve based on a first design pressure included in the stored first equipment information.

[0009] A refrigeration cycle apparatus according to a fourth aspect is the refrigeration cycle apparatus according to any one of the first aspect to the third aspect, wherein the first usage unit has a first sensor. The first sensor detects refrigerant leakage. 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 usage unit through the first refrigerant piping.

[0010] With such a configuration, the refrigeration cycle apparatus of the fourth aspect can use the first degree of opening adjustment valve as a shutoff valve that shuts off leakage of the refrigerant.

[0011] A refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to the fourth aspect, wherein the plurality of utilization units further includes a second utilization unit different from the first utilization unit. When the first sensor detects a refrigerant leak, the control unit controls a second degree-of-opening adjustment valve provided in a second refrigerant pipe on a high pressure side connected to the second utilization unit.

[0012] With such a configuration, the refrigeration cycle device of the fifth aspect can prevent the pressure of the refrigerant flowing through the second usage unit from increasing and damaging the second usage unit by fully closing the first opening adjustment valve. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing a refrigerant circuit of a refrigeration cycle device in a first embodiment. [Diagram 2] FIG. 2 is a control block diagram of the refrigeration cycle device in the first embodiment. [Diagram 3] FIG. 6 is a diagram showing a refrigerant circuit of a refrigeration cycle device in a second embodiment. [Figure 4] FIG. 11 is a diagram showing a refrigerant circuit of a refrigeration cycle device in a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] First Embodiment (1) Overall structure 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 communicatively connected 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.

[0015] (2) Detailed configuration (2-1) Usage unit Since the utilization units 20 and 20a have basically the same structure, the utilization unit 20 (first utilization unit) will be described below.

[0016] 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 type unit, a ceiling suspended type unit, or a floor-standing type 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, 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 and a liquid refrigerant connection pipe 55 that is formed by branching the liquid refrigerant connection pipe 51 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 and a gas refrigerant connection pipe 56 that is formed by branching the gas refrigerant connection pipe 52 to the utilization unit 20 side. The liquid refrigerant pipe 57 and the gas refrigerant pipe 58 are provided in the utilization unit 20.

[0017] (2-1-1) Heat exchanger used 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.

[0018] (2-1-2) Fans in use The utilization fan 22 supplies air from 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.

[0019] (2-1-3) 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 electrically operated valve whose opening degree can be adjusted.

[0020] (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.

[0021] 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.

[0022] (2-1-5) Usage Control Unit The utilization control unit 29 is connected to various devices of 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, so as to be able to communicate with each other.

[0023] The usage control unit 29 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 according to the program, thereby controlling the operation of various devices possessed by the usage unit 20. The control arithmetic device can also write the results of the calculations to the storage device and read out information stored in the storage device according to the program.

[0024] 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 air volume.

[0025] 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.

[0026] (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.

[0027] The suction pipe 54a connects the flow path switching valve 32 and the suction side of the compressor 31. The 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. The liquid refrigerant pipe 54d is provided with the heat source expansion valve 34. The liquid stop valve 37 is provided at the connection part 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. The gas stop valve 38 is provided at the connection part 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.

[0028] (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.

[0029] The compressor 31 is, for example, a volumetric compressor of a rotary type, a scroll type, etc. 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.

[0030] (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.

[0031] 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 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.

[0032] 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 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.

[0033] (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.

[0034] (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.

[0035] (2-2-5) Accumulator The accumulator 35 is a container having a gas-liquid separation function that separates the refrigerant flowing 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 flowing 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.

[0036] (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.

[0037] (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.

[0038] 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.

[0039] (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.

[0040] 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 a program stored in the storage device and performs a predetermined arithmetic process according to the program, thereby controlling the operation of various devices of 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 according to the program.

[0041] 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 utilization unit 20 and the opening control unit 89 of the opening adjustment unit 80. The heat source control unit 39, the usage control unit 29, and the opening control unit 89 cooperate to function as the control unit 40.

[0042] (2-3) Opening adjustment unit Since the opening degree adjustment units 80, 80a have basically the same structure, the opening degree adjustment unit 80 will be described below.

[0043] 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.

[0044] 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 (first opening adjustment valve) is provided in the high pressure side liquid refrigerant communication pipe 55 (first refrigerant pipe) connected to the utilization unit 20 during cooling operation.

[0045] The gas opening adjustment valve 82 is provided in the gas refrigerant communication piping 56 connected to the utilization unit 20. In other words, the gas opening adjustment valve 82 (first opening adjustment valve) is provided in the high-pressure side gas refrigerant communication piping 56 (first refrigerant piping) connected to the utilization unit 20 during heating operation.

[0046] The liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82 are motor-operated valves capable of adjusting the aperture. 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 connection 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 connection pipe 56.

[0047] The opening control section 89 is connected to be able to communicate with various devices included in the opening adjustment unit 80, including the liquid opening adjustment valve 81 and the gas opening adjustment valve .

[0048] 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 according to the program, thereby controlling the operation of various devices of 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 according to the program.

[0049] 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, the usage control unit 29, and the heat source control unit 39 work together to function as the control unit 40.

[0050] (2-4) Control section 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.

[0051] 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 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 of the refrigeration cycle apparatus 1 based on control signals received from the operation remote control via the utilization unit 20, measurement signals of various sensors, and the like.

[0052] The control unit 40 mainly performs a cooling operation and a heating operation, and mainly has a function of preventing refrigerant leakage.

[0053] (2-4-1) Cooling operation When the control unit 40 receives an instruction to perform cooling operation via the utilization unit 20, for example, from an operation remote control, the control unit 40 acquires equipment information of the utilization unit 20 from the utilization unit 20. The equipment information of the utilization unit 20 includes the design pressure of the utilization unit 20, the capacity of the utilization unit 20, the type of utilization expansion valve 23, etc. The control unit 40 controls the liquid opening adjustment valve 81 based on the design pressure of the utilization unit 20, which is included in the equipment information of the utilization unit 20.

[0054] The design pressure of the utilization unit 20 is the allowable pressure of the refrigerant flowing in the utilization unit 20 (specifically, the refrigerant flowing in the liquid refrigerant pipe 57, the gas refrigerant pipe 58, and the utilization heat exchanger 21). The design pressure of the utilization unit 20 is, for example, the actual pressure resistance value of the utilization unit 20 multiplied by a safety factor. The design pressure of the utilization unit generally differs depending on the type of refrigerant that the utilization unit can handle. For example, the design pressure of the utilization unit differs when the type of refrigerant that the utilization unit can handle is R22, when it is R407c, and when it is R32 or R410. The control unit 40 determines the first upper limit value of the opening degree of the liquid opening degree adjustment valve 81 so that the pressure of the refrigerant flowing in the utilization unit 20 does not exceed the design pressure of the utilization unit 20. The smaller the design pressure of the utilization unit 20, the smaller the first upper limit value. The control unit 40 fixes the opening degree of the liquid opening degree adjustment valve 81 to the first upper limit value during cooling operation. Moreover, 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 the gas aperture adjustment valve 82, and controls 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. The target evaporation temperature is set, for example, according to a set temperature received from the operation remote control.

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

[0057] 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, and condenses through heat exchange with the air around the heat source unit 30 supplied by the heat source fan 36 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 to near the suction pressure of the compressor 31 in the utilization expansion valve 23, becomes a gas-liquid two-phase refrigerant, and is sent to the utilization heat exchanger 21. The gas-liquid two-phase 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 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 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.

[0058] (2-4-2) Heating operation When the control unit 40 receives an instruction to perform heating operation via the utilization unit 20 from, for example, an operation remote controller, the control unit 40 acquires device information of the utilization unit 20 from the utilization unit 20. The control unit 40 controls the gas degree of opening adjustment valve 82 based on the design pressure of the utilization unit 20 included in the device information of the utilization unit 20. Specifically, the control unit 40 determines a second upper limit value of the opening degree of the gas degree of opening adjustment valve 82 so that the pressure of the refrigerant flowing in the utilization unit 20 does not exceed the design pressure of the utilization unit 20. The smaller the design pressure of the utilization unit 20, the smaller the second upper limit value. The control unit 40 fixes the opening degree of the gas degree of opening adjustment valve 82 to the second upper limit value during heating operation. In addition, the control unit 40 switches the flow path switching valve 32 to the second state.

[0059] Then, the control unit 40 fully opens the liquid opening adjustment valve 81 and controls 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. 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 opening of the heat source expansion valve 34 so that the refrigerant flowing into the heat source heat exchanger 33 is reduced in pressure to a pressure at which the refrigerant can evaporate in the heat source heat exchanger 33.

[0060] As described above, the operations of the various devices are controlled, so that the refrigerant flows through the refrigerant circuit 50 during heating operation as follows.

[0061] 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 by heat exchange with the air in the target space supplied to the utilization heat exchanger 21 by the utilization fan 22, becoming a high-pressure liquid refrigerant. The temperature of the air supplied to the utilization heat exchanger 21 is increased by 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, and evaporates, 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 sucked into the compressor 31 again.

[0062] (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 connection 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 connection pipe 56. The control unit 40 may further fully close the utilization expansion valve 23.

[0063] 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 (here, the utilization unit 20a will be described) increases, which may damage the utilization unit 20a. Therefore, if the refrigerant sensor 61 detects a refrigerant leak, and if the utilization unit 20a is in cooling operation, the control unit 40 may fully close the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82 as shown in Fig. 1, and then control the liquid aperture adjustment valve 81a provided in the high-pressure liquid refrigerant connection pipe 55a connected to the utilization unit 20a. Specifically, the control unit 40 lowers the upper limit of the aperture of the liquid aperture adjustment valve 81a. Similarly, when the refrigerant sensor 61 detects a refrigerant leak, if the utilization unit 20a is in heating operation, the control unit 40 may fully close the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82, and then control the gas aperture adjustment valve 82a provided in the high-pressure side gas refrigerant communication pipe 56a connected to the utilization unit 20a. Specifically, the control unit 40 lowers the upper limit of the aperture of the gas aperture adjustment valve 82a.

[0064] (3) Features (3-1) Conventionally, there is a technology for controlling the pressure of the refrigerant flowing in the utilization unit using a pressure sensor provided in the heat source unit. When the pressure of the refrigerant flowing in the utilization unit is controlled using a pressure sensor provided in the heat source unit, the pressure of the refrigerant flowing in the multiple utilization units connected to the heat source unit is set to a uniform value. Therefore, when multiple utilization units with different design pressures are connected to the heat source unit, the pressure of the refrigerant flowing in the multiple utilization units is adjusted to that of the utilization unit with the lowest design pressure, and there is a problem that utilization units with a relatively high design pressure cannot fully demonstrate their capabilities.

[0065] The refrigeration cycle device 1 of this embodiment includes a heat source unit 30, a plurality of utilization units 20, 20a, liquid aperture adjustment valves 81, 81a, gas aperture adjustment valves 82, 82a, and a control unit 40. The utilization units 20, 20a constitute a refrigerant circuit 50 together with the heat source unit 30. The utilization units 20, 20a include a utilization unit 20. The liquid aperture adjustment valve 81 is provided in a high-pressure liquid refrigerant connection pipe 55 connected to the utilization unit 20 during cooling operation. The control unit 40 controls the liquid aperture adjustment valve 81 based on the design pressure of the utilization unit 20. The gas aperture adjustment valve 82 is provided in a high-pressure gas refrigerant connection pipe 56 connected to the utilization unit 20 during heating operation. The control unit 40 controls the gas aperture adjustment valve 82 based on the design pressure of the utilization unit 20.

[0066] In the refrigeration cycle apparatus 1, the control unit 40 controls the liquid aperture adjustment valve 81 provided in the high-pressure side liquid refrigerant connection pipe 55 during cooling operation based on the design pressure of the utilization unit 20. The control unit 40 controls the gas aperture adjustment valve 82 provided in the high-pressure side gas refrigerant connection pipe 56 during heating operation based on the design pressure of the utilization unit 20. Therefore, the refrigeration cycle apparatus 1 can control the pressure of the refrigerant flowing in the utilization units 20, 20a based on the design pressure for each of the utilization units 20, 20a. As a result, even when a plurality of utilization units 20, 20a with different design pressures are connected to the heat source unit 30, each utilization unit 20, 20a can fully demonstrate its capacity.

[0067] (3-2) In the refrigeration cycle apparatus 1 of the present embodiment, the control unit 40 acquires equipment information from the utilization unit 20. The control unit 40 controls the liquid aperture adjustment valve 81 or the gas aperture adjustment valve 82 based on the design pressure of the utilization unit 20, which is included in the equipment information of the utilization unit 20.

[0068] As a result, the refrigeration cycle apparatus 1 can control the pressure of the refrigerant flowing inside each of the utilization units 20, 20a based on the information acquired from the utilization units 20, 20a.

[0069] (3-3) In the refrigeration cycle apparatus 1 of the present embodiment, the utilization unit 20 has a refrigerant sensor 61. The refrigerant sensor 61 detects refrigerant leakage. When the refrigerant sensor 61 detects refrigerant leakage, the control unit 40 fully closes the liquid aperture adjustment valve 81 to block refrigerant leaking from the utilization unit 20 through the liquid refrigerant connection pipe 55. The control unit 40 fully closes the gas aperture adjustment valve 82 to block refrigerant leaking from the utilization unit 20 through the gas refrigerant connection pipe 56.

[0070] As a result, the refrigeration cycle device 1 can use the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82 as shutoff valves that shut off leakage of the refrigerant.

[0071] (3-4) In the refrigeration cycle apparatus 1 of this embodiment, the multiple utilization units 20, 20a further include a utilization unit 20a different from the utilization unit 20. When the refrigerant sensor 61 detects a refrigerant leak, if the utilization unit 20a is in cooling operation, the control unit 40 controls the liquid aperture adjustment valve 81a provided in the high-pressure side liquid refrigerant connection pipe 55a connected to the utilization unit 20a. When the refrigerant sensor 61 detects a refrigerant leak, if the utilization unit 20a is in heating operation, the control unit 40 controls the gas aperture adjustment valve 82a provided in the high-pressure side gas refrigerant connection pipe 56a connected to the utilization unit 20a.

[0072] As a result, by fully closing the liquid aperture adjustment valve 81 and the gas aperture adjustment valve 82, the refrigeration cycle device 1 can prevent the pressure of the refrigerant flowing within the utilization unit 20a from increasing and damaging the utilization unit 20a.

[0073] (4) Variations (4-1) Variation 1A In this embodiment, when the control unit 40 receives an instruction to perform cooling operation via the utilization unit 20, for example from an operation remote control, the control unit 40 acquires equipment information of the utilization unit 20 from the utilization unit 20 each time, and controls the liquid opening adjustment valve 81 based on the design pressure of the utilization unit 20 contained in the equipment information of the utilization unit 20.

[0074] However, the control unit 40 may store previously acquired equipment information of the utilization unit 20, and when the control unit 40 next receives an instruction to perform cooling operation, the control unit 40 may control the liquid opening adjustment valve 81 based on the design pressure of the utilization unit 20 contained in the stored equipment information of the utilization unit 20. The same applies to heating operation.

[0075] (4-2) Variation 1B The opening 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. The opening adjustment unit 80 is preferably provided for a utilization unit having a relatively low design pressure.

[0076] (4-3) Variation 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 described in the claims.

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

[0079] Fig. 3 is a diagram showing a refrigerant circuit 50 of the refrigeration cycle device 1 in this embodiment. As shown in Fig. 3, the utilization unit 20 in this embodiment does not have a utilization expansion valve 23, unlike the utilization unit 20 in the first embodiment.

[0080] When performing cooling operation, the liquid opening adjustment valve 81 also functions as the utilization expansion valve 23. Specifically, the control unit 40 increases or decreases the opening of the liquid opening adjustment valve 81 with the first upper limit value as the upper limit (without fixing it to the first upper limit value) so that the evaporation temperature, which is the measurement value of the saturation temperature sensor 64, becomes the target evaporation temperature.

[0081] Even during heating operation, the liquid aperture adjustment valve 81 also functions as the utilization expansion valve 23. Specifically, the control unit 40 increases or decreases the aperture of the liquid aperture adjustment valve 81 so that the condensing temperature, which is the measurement value of the saturation temperature sensor 64, becomes the target condensing temperature.

[0082] As a result, the refrigeration cycle apparatus 1 can control the pressure of the refrigerant flowing inside the utilization unit 20 based on the design pressure of the utilization unit 20.

[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 described in the claims.

[0084] <Third embodiment> The following description will focus on the differences from the first embodiment.

[0085] Fig. 4 is a diagram showing the refrigerant circuit 50 of the refrigeration cycle device 1 in this embodiment. As shown in Fig. 4, 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.

[0086] As a result, at least during heating operation, the refrigeration cycle apparatus 1 can control the pressure of the refrigerant flowing inside the utilization unit 20 based on the design pressure of the utilization unit 20.

[0087] The opening degree 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. The opening degree adjustment unit 801 is preferably provided for utilization units having a relatively low design pressure. Also, as shown in Fig. 4, a different type of opening degree adjustment unit may be provided for each of the multiple utilization units, such as providing an opening degree adjustment unit 801 for utilization unit 20 and providing an opening degree adjustment unit 80a for utilization unit 20a.

[0088] 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. [Explanation of symbols]

[0089] 1 Refrigeration cycle equipment 20 User Unit (First User Unit) 20a User Unit (Second User Unit) 30 Heat source unit 40 Control section 50 Refrigerant circuit 55 Liquid refrigerant connecting piping (first refrigerant piping) 55a Liquid refrigerant connecting piping (second refrigerant piping) 56 Gas refrigerant connecting piping (first refrigerant piping) 56a Gas refrigerant connection piping (second refrigerant piping) 61 Refrigerant sensor (first sensor) 81 Liquid opening adjustment valve (first opening adjustment valve) 81a Liquid opening adjustment valve (second opening adjustment valve) 82 Gas opening adjustment valve (first opening adjustment valve) 82a Gas opening adjustment valve (second opening adjustment valve) [Prior art documents] [Patent documents]

[0090] [Patent Document 1] JP 2023-030403 A

Claims

1. A heat source unit (30); 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 (81, 82) provided in a first refrigerant pipe (55, 56) on a high pressure side connected to the first utilization unit; A control unit (40); Equipped with the control unit controls the first degree-of-opening adjustment valve based on a first design pressure of the first utilization unit. Refrigeration cycle device (1).

2. The control unit is Acquire first device information from the first utilization unit; controlling the first degree of opening adjustment valve based on the first design pressure included in the first device information; A refrigeration cycle device (1) as claimed in claim 1.

3. The control unit is storing the acquired first device information; controlling the first degree of opening adjustment valve based on the first design pressure included in the stored first device information; A refrigeration cycle device (1) according to claim 2.

4. The first utilization unit has a first sensor (61) for detecting leakage of a refrigerant, 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. A refrigeration cycle device (1) according to any one of claims 1 to 3.

5. The plurality of utilization units further includes a second utilization unit (20a) different from the first utilization unit, When the first sensor detects a refrigerant leak, the control unit controls a second opening adjustment valve (81 a, 82 a) provided in a second refrigerant pipe (55 a, 56 a) on a high pressure side connected to the second usage unit. Refrigeration cycle device (1) according to claim 4.

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