Refrigeration cycle device

Abstract

To provide a refrigeration cycle device that can deal with refrigerant leakage from a utilization unit while reducing the number of components.SOLUTION: An air conditioner 100 comprises a heat source unit 10 comprising a compressor 12 and a heat source heat exchanger 16, a plurality of utilization units 30 each comprising a utilization heat exchanger 32, a gas pipe GP connecting the compressor of the heat source unit and the utilization heat exchanger of each of the plurality of utilization units, and a shut-off valve 52. The gas pipe includes a first pipe 4a extending from the heat source unit, second pipes 4b extending from the utilization units, and a branch part 4c for branching the first pipe into a plurality of the second pipes. The shut-off valve is arranged closer to the heat source unit than the branch part in the gas pipe. Each of the utilization units comprises a utilization expansion valve 36 provided in a liquid pipe L connecting the utilization heat exchanger of each of the utilization units and the heat source heat exchanger of the heat source unit, and whose opening degree can be adjusted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a refrigeration cycle device.

Background Art

[0002] As disclosed in Patent Document 1 (Japanese Patent No. 6927315), a refrigeration cycle device is known in which shut-off valves are provided in each of a plurality of utilization units having a utilization heat exchanger and a utilization expansion valve, and the shut-off valves are closed when refrigerant leaks.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In such a refrigeration cycle device, a large number of shut-off valves are required in the refrigerant piping according to the number of utilization units.

Means for Solving the Problems

[0004] The refrigeration cycle device of the first aspect includes a heat source unit, a plurality of utilization units, a gas pipe, and a first shut-off valve. The heat source unit has a compressor and a heat source heat exchanger. Each of the plurality of utilization units has a utilization heat exchanger. The gas pipe connects the compressor of the heat source unit and the utilization heat exchangers of the plurality of utilization units. The gas pipe includes a first pipe extending from the heat source unit, a second pipe extending from the utilization unit, and a branch portion that branches the first pipe into a plurality of second pipes. The first shut-off valve is disposed in the gas pipe closer to the heat source unit than the branch portion. Each utilization unit has an opening-adjustable second shut-off valve provided in a liquid pipe that connects the utilization heat exchanger of the utilization unit and the heat source heat exchanger of the heat source unit.

[0005] In the refrigeration cycle device of the first aspect, a first shut-off valve common to the plurality of utilization units is provided in the gas pipe, and an opening-adjustable second shut-off valve (a shut-off valve also used as an expansion valve) is provided for each utilization unit. Therefore, in the refrigeration cycle device of the first aspect, the number of components can be reduced while responding to refrigerant leakage from the utilization units.

[0006] The refrigeration cycle device from the second perspective is the refrigeration cycle device from the first perspective, and the first shut-off valve is a flow rate adjustment valve with adjustable opening degree.

[0007] In this refrigeration cycle device, the first shut-off valve can be used not only as a shut-off valve but also for flow rate adjustment purposes, reducing the number of components.

[0008] The refrigeration cycle device from the third perspective is the refrigeration cycle device from the first or second perspective, and each utilization unit further has a refrigerant sensor. When the refrigerant sensor of one utilization unit detects refrigerant leakage, the first shut-off valve and the second shut-off valves of the plurality of utilization units connected to the heat source unit via the first shut-off valve by the gas pipe are closed.

[0009] In the refrigeration cycle device from the third perspective, while reducing the number of components, it is possible to suppress the occurrence of a situation where the concentration of leaked refrigerant becomes high in the space where the utilization units are installed.

[0010] The refrigeration cycle device from the fourth perspective is the refrigeration cycle device from the third perspective, and the utilization unit further has a controller. When the refrigerant sensor of each utilization unit detects refrigerant leakage, it sends a signal to the controller of the utilization unit where the refrigerant sensor is provided. The controller of the utilization unit where the refrigerant sensor that has detected refrigerant leakage is provided sends a closing command for the second shut-off valve to the controllers of the other utilization units connected to the heat source unit via the first shut-off valve by the gas pipe together with the utilization unit where the leakage has been detected.

[0011] In the refrigeration cycle device from the fourth perspective, since the utilization unit receives a closing command for the second shut-off valve from a utilization unit arranged nearby without passing through the heat source unit, it is possible to quickly cut off the inflow of refrigerant from the heat source unit to the utilization unit when refrigerant leakage occurs.

[0012] The refrigeration cycle device according to the fifth aspect is the refrigeration cycle device according to the fourth aspect, and when the utilization unit receives a closing command of the second shut-off valve, it stops operating.

[0013] In this refrigeration cycle device, since the operation of the utilization unit is stopped, a situation where the refrigerant flowing out from the utilization unit diffuses into the space where the utilization unit is installed is likely to be suppressed.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0015] Embodiments of the refrigeration cycle device will be described with reference to the drawings.

[0016] <First Embodiment> (1) Overall Configuration The air conditioner 100 which is the first embodiment of the refrigeration cycle device will be described. Note that the refrigeration cycle device of the present disclosure is not limited to an air conditioner, and may be a hot water supply device or a floor heating device.

[0017] The air conditioner 100 of the first embodiment will be described with reference to the schematic configuration diagram of FIG. 1.

[0018] The air conditioner 100 is a device that air - conditions a plurality of air - conditioned spaces within a building. The air conditioner 100 mainly includes a heat source unit 10, a plurality of user units 30, one shut - off valve unit 50 shared by the plurality of user units 30, and a control unit 70 (see FIG. 1). Note that the number of user units 30 drawn in FIG. 1 does not limit the number of user units 30 that the air conditioner 100 has.

[0019] As shown in FIG. 1, the heat source unit 10 and the user unit 30 are connected by connection pipes 2 and 4. By connecting the heat source unit 10 and the user unit 30 with the connection pipes 2 and 4, a refrigerant circuit 90 including a compressor 12, a heat source heat exchanger 16, a heat source expansion valve 18, a user expansion valve 36, a user heat exchanger 32, etc., which will be described later, is formed. The shut - off valve unit 50 is provided in the connection pipe 4. The connection pipe 4 is a gas connection pipe through which refrigerant flows from the user unit 30 to the heat source unit 10 during cooling operation, and from the heat source unit 10 to the user unit 30 during heating operation. The control unit 70 controls the operations of each part of the air conditioner 100.

[0020] (2) Detailed configuration (2 - 1) User unit The user unit 30 is installed in the air - conditioned space that is the object of air - conditioning. The user unit 30 is, for example, a ceiling - embedded type, ceiling - suspended type, wall - mounted type, floor - standing type unit, etc. In this embodiment, the case where the user unit 30 is a ceiling - embedded type will be taken as an example for the following description.

[0021] Each utilization unit 30 mainly includes a utilization heat exchanger 32, a utilization fan 34, a utilization expansion valve 36, a utilization control unit 72, a refrigerant sensor 38, and a casing 31 that houses these components.

[0022] In the utilization heat exchanger 32, heat exchange is performed between the refrigerant flowing inside the utilization heat exchanger 32 and the air in the air-conditioned space. The utilization heat exchanger 32 is, for example, a fin-and-tube type heat exchanger having a plurality of heat transfer fins and a plurality of heat transfer tubes.

[0023] The utilization fan 34 supplies the air taken in from the air-conditioned space to the utilization heat exchanger 32. The utilization fan 34 is, for example, a centrifugal fan such as a turbo fan or a sirocco fan. The utilization fan 34 is driven by a motor (not shown).

[0024] The utilization expansion valve 36 is an example of a second shut-off valve. Here, the pipe connecting the liquid end of the utilization heat exchanger 32 and the communication pipe 2, the communication pipe 2, and the liquid refrigerant pipe 28d are collectively referred to as the liquid pipe LP, and the utilization expansion valve 36 is provided in the liquid pipe LP. In particular, in the present embodiment, the utilization expansion valve 36 is provided in the pipe connecting the communication pipe 2 and the liquid side end of the utilization heat exchanger 32, and is a mechanism for adjusting the pressure and flow rate of the refrigerant. The utilization expansion valve 36 is an electric valve (electronic expansion valve) whose opening can be adjusted. Note that the utilization expansion valve 36 is also used as a shut-off valve when refrigerant leaks, and is a valve with a small leakage amount when closed. For example, the utilization expansion valve 36 has a leakage amount of 300 cm 3 / min (air, ΔP = 1.0 MPa) or less when closed.

[0025] The refrigerant sensor 38 is a sensor that detects refrigerant leakage. The refrigerant sensor 38 is provided, for example, near the utilization heat exchanger 32.

[0026] The control unit 72 includes a control arithmetic unit and a storage device. The control arithmetic unit is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic unit reads out a program stored in the storage device and performs predetermined arithmetic processing according to the program, thereby cooperating with the heat source control unit 74 of the heat source unit 10 and the valve control unit 76 of the shutoff valve unit 50 to control the operations of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

[0027] (2-2) Heat source unit The heat source unit 10 is installed on the rooftop or machine room of the building where the air conditioner 100 is installed. As shown in FIG. 1, the heat source unit 10 mainly includes a compressor 12, a flow path switching valve 14, a heat source heat exchanger 16, a heat source expansion valve 18, an accumulator 20, a heat source fan 22, a liquid shutoff valve 24, a gas shutoff valve 26, and a heat source control unit 74. The heat source unit 10 also includes a suction pipe 28a, a discharge pipe 28b, gas refrigerant pipes 28c and 28e, and a liquid refrigerant pipe 28d.

[0028] The suction pipe 28a connects the flow path switching valve 14 and the suction side of the compressor 12. An accumulator 20 is provided in the suction pipe 28a. The discharge pipe 28b connects the discharge side of the compressor 12 and the flow path switching valve 14. The gas refrigerant pipe 28c connects the flow path switching valve 14 and the gas side end of the heat source heat exchanger 16. The liquid refrigerant pipe 28d connects the liquid side end of the heat source heat exchanger 16 and the communication pipe 2. A heat source expansion valve 18 is provided in the liquid refrigerant pipe 28d. A liquid shutoff valve 24 is provided at the connection portion between the liquid refrigerant pipe 28d and the communication pipe 2. The gas refrigerant pipe 28e connects the flow path switching valve 14 and the communication pipe 4. A gas shutoff valve 26 is provided at the connection portion between the gas refrigerant pipe 28e and the communication pipe 4. The liquid shutoff valve 24 and the gas shutoff valve 26 are manually operated valves.

[0029] The compressor 12 sucks in the low-pressure refrigerant in the refrigeration cycle from the suction pipe 28a, compresses the refrigerant by a compression mechanism (not shown), and discharges the high-pressure refrigerant in the refrigeration cycle after compression to the discharge pipe 28b. The compressor 12 is, for example, a positive displacement compressor such as a rotary type or a scroll type. The compression mechanism of the compressor 12 is driven by a motor (not shown). The rotation speed of the motor of the compressor 12 can be controlled by an inverter.

[0030] The flow path switching valve 14 is a mechanism that switches the flow path of the refrigerant between a first state and a second state. In the first state, the flow path switching valve 14 connects the suction pipe 28a to the gas refrigerant pipe 28e and the discharge pipe 28b to the gas refrigerant pipe 28c, as shown by the solid line in the flow path switching valve 14 of FIG. 1. In the second state, the flow path switching valve 14 connects the suction pipe 28a to the gas refrigerant pipe 28c and the discharge pipe 28b to the gas refrigerant pipe 28e, as shown by the broken line in the flow path switching valve 14 of FIG. 1. The flow path switching valve 14 is, for example, a four-way switching valve.

[0031] During the cooling operation, the flow path switching valve 14 sets the flow path of the refrigerant to the first state. At this time, the refrigerant discharged from the compressor 12 flows through the refrigerant circuit 90 in the order of the heat source heat exchanger 16, the heat source expansion valve 18, the utilization expansion valve 36, and the utilization heat exchanger 32, and returns to the compressor 12. In the first state, the heat source heat exchanger 16 functions as a condenser, and the utilization heat exchanger 32 functions as an evaporator.

[0032] During the heating operation, the flow path switching valve 14 sets the flow path of the refrigerant to the second state. At this time, the refrigerant discharged from the compressor 12 flows through the refrigerant circuit 90 in the order of the utilization heat exchanger 32, the utilization expansion valve 36, the heat source expansion valve 18, and the heat source heat exchanger 16, and returns to the compressor 12. In the second state, the heat source heat exchanger 16 functions as an evaporator, and the utilization heat exchanger 32 functions as a condenser.

[0033] The heat source heat exchanger 16 performs heat exchange between the refrigerant flowing inside the heat source heat exchanger 16 and the air around the heat source unit 10. The heat source heat exchanger 11 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] The heat source expansion valve 18 is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 28d. As shown in FIG. 1, the heat source expansion valve 18 is provided in the liquid refrigerant pipe 28d. The heat source expansion valve 18 is an electric valve (electronic expansion valve) whose opening degree can be adjusted.

[0035] The accumulator 20 is provided in the suction pipe 28a and is a container having a gas-liquid separation function for separating the flowing-in refrigerant into a gas refrigerant and a liquid refrigerant. The refrigerant flowing into the accumulator 20 is separated into a gas refrigerant and a liquid refrigerant, and the gas refrigerant gathering in the upper space flows into the compressor 12.

[0036] The heat source fan 22 supplies air around the heat source unit 10 to the heat source heat exchanger 16. The heat source fan 22 is, for example, an axial flow fan such as a propeller fan. The heat source fan 22 is driven by a motor (not shown).

[0037] The heat source control unit 74 has a control arithmetic unit and a storage device. The control arithmetic unit is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic unit reads out the program stored in the storage device and performs a predetermined arithmetic process according to the program, so as to cooperate with the utilization control unit 72 of the utilization unit 30 and the valve control unit 76 of the shut-off valve unit 50, and controls the operations of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

[0038] (2-3) Shut-off valve unit The communication pipe 4, the gas refrigerant pipe 28e, and the suction pipe 28a or the discharge pipe 28b constitute the gas pipe GP in the claims. The gas pipe GP connects the compressor 12 of the heat source unit 10 and the utilization heat exchanger 32 of the plurality of utilization units 30. The gas pipe GP includes a first pipe 4a extending from the heat source unit 10, a second pipe 4b extending from the utilization unit 30, and a branch portion 4c that branches the first pipe 4a into a plurality of second pipes 4b. The first pipe 4a is a portion of the communication pipe 4 that connects the heat source unit 10 and the branch portion 4c. The second pipe 4b is a portion of the communication pipe 4 that connects the utilization unit 30 and the branch portion 4c.

[0039] The shut-off valve unit 50 is arranged on the first pipe 4a of the communication pipe 4. The shut-off valve unit 50 has a shut-off valve 52 as an example of a first shut-off valve arranged closer to the heat source unit 10 than the branch portion 4c in the gas pipe GP. One shut-off valve unit 50 is provided corresponding to the plurality of utilization units 30. In the present embodiment, one shut-off valve unit 50 is provided for all the utilization units 30. The shut-off valve unit 50 is a unit that shuts off the flow of the refrigerant when there is a refrigerant leak in the corresponding utilization unit 30 or the like.

[0040] The shut-off valve unit 50 is arranged, for example, outside the air-conditioned space. For example, the shut-off valve unit 50 is arranged in the space above the ceiling of the air-conditioned space, the underfloor space of the air-conditioned space, or the space above the ceiling of the corridor adjacent to the air-conditioned space. Note that the installation location of the shut-off valve unit 50 is not limited to the exemplified locations and may be determined as appropriate.

[0041] The shut-off valve unit 50 mainly has a shut-off valve 52, a casing 54, and a valve control unit 76.

[0042] The shut-off valve 52 is a valve with a small leakage amount when closed. For example, the shut-off valve 52 is an electromagnetic valve with a leakage amount of 300 cm 3 / min (air, ΔP = 1.0 MPa) or less. However, the type of the valve is not limited to the electromagnetic valve, and an electric valve or the like that can adjust the opening degree may be used.

[0043] The casing 54 is a housing that houses the shut-off valve 52 inside. An anti-condensation material is arranged inside the casing 54, thereby suppressing condensation around the shut-off valve 52.

[0044] The valve control unit 76 has a control arithmetic unit and a storage device. The control arithmetic unit is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic unit reads out the program stored in the storage device and performs predetermined arithmetic processing according to the program, so as to cooperate with the usage control unit 72 of the usage unit 30 and the heat source control unit 74 of the heat source unit 10, and controls the operations of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

[0045] (2-4) Control Unit The control unit 70 is composed of a usage control unit 72, a heat source control unit 74, and a valve control unit 76. The control unit 70 controls the operations of the entire air conditioner 100 by causing the control arithmetic units of the usage control unit 72, the heat source control unit 74, and the valve control unit 76 to execute the programs stored in their respective storage devices.

[0046] Figure 2 is a control block diagram of the air conditioner 100 in the present embodiment.

[0047] As shown in FIG. 2, the control unit 70 is electrically connected to the usage expansion valve 36, the usage fan 34, and the refrigerant sensor 38 of each of the plurality of usage units 30, the compressor 12, the flow path switching valve 14, the heat source expansion valve 18, and the heat source fan 22 of the heat source unit 10, and the shut-off valve 52 of each of the plurality of shut-off valve units 50. Further, the control unit 70 is electrically connected to various sensors that measure the temperature and pressure of the refrigerant, the temperature of the air in the air-conditioned space, the outside air temperature, etc. The control unit 70 controls the operations of various devices of the air conditioner 100 based on the control signals received by the usage unit 30 from an operation remote control (not shown) and the measurement signals of various sensors.

[0048] The control unit 70 mainly performs cooling operation and heating operation. Further, the control unit 70 has a refrigerant leakage prevention function.

[0049] (2-5-1) Cooling operation When the control unit 70 receives a command to perform a cooling operation, for example, from an operation remote control via the usage unit 30, it sets the flow path switching valve 14 to the first state and starts the operation of the compressor 12. Also, based on the measurement results of sensors that measure the temperature and pressure of the refrigerant provided in the refrigerant circuit 90, the control unit appropriately controls the rotational speed of the motor of the compressor 12 and the opening degrees of the heat source expansion valve 18 and the usage expansion valve 36. During the cooling operation, the shut-off valve 52 is controlled to be fully open.

[0050] The flow of the refrigerant in the refrigerant circuit 90 will be described. When the operation of the compressor 12 is started, the low-pressure (hereinafter simply referred to as low-pressure) gas refrigerant in the refrigeration cycle is sucked into the compressor 12 and compressed by the compression mechanism of the compressor 12 to become a high-pressure (hereinafter simply referred to as high-pressure) gas refrigerant in the refrigeration cycle. The high-pressure gas refrigerant is sent to the heat source heat exchanger 16 via the flow path switching valve 14, exchanges heat with the air around the heat source unit 10 supplied by the heat source fan 22, and condenses to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows through the liquid refrigerant pipe 28d and passes through the heat source expansion valve 18. The high-pressure liquid refrigerant sent to the usage unit 30 is decompressed to near the suction pressure of the compressor 12 at the usage expansion valve 36, becomes a refrigerant in a gas-liquid two-phase state, and is sent to the usage heat exchanger 32. The refrigerant in the gas-liquid two-phase state exchanges heat with the air in the air-conditioning space supplied to the usage heat exchanger 32 by the usage fan 34 in the usage heat exchanger 32, evaporates, and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerants flowing out from the plurality of usage units 30 merge, are sent to the heat source unit 10 via the connection pipe 4 and the shut-off valve unit 50, and flow into the accumulator 20 via the flow path switching valve 14. The low-pressure gas refrigerant flowing into the accumulator 20 is sucked into the compressor 12 again. Note that the temperature of the air supplied to the usage heat exchanger 32 decreases by exchanging heat with the refrigerant flowing through the usage heat exchanger 32, and the cooled air blows out into the air-conditioning space.

[0051] (2-5-2) Heating operation When the control unit 70 receives a command to perform a heating operation, for example, from an operation remote control via the usage unit 30, it sets the flow path switching valve 14 to the second state and starts the operation of the compressor 12. Further, based on the measurement results of sensors provided in the refrigerant circuit 90 for measuring the temperature and pressure of the refrigerant, the rotation speed of the motor of the compressor 12 and the opening degrees of the heat source expansion valve 18 and the usage expansion valve 36 are appropriately controlled. During the heating operation, the shut-off valve 52 is controlled to be fully open.

[0052] The flow of the refrigerant in the refrigerant circuit 90 will be described. When the compressor 12 is started, low-pressure gaseous refrigerant is sucked into the compressor 12, compressed by the compressor 12, and becomes high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant passes through the shut-off valve unit 50, is sent to the usage heat exchanger 32 via the flow path switching valve 14, and exchanges heat with the air in the air-conditioning space supplied to the usage heat exchanger 32 by the usage fan 34, condenses, and becomes high-pressure liquid refrigerant. The temperature of the air supplied to the usage heat exchanger 32 rises by exchanging heat with the refrigerant flowing through the usage heat exchanger 32, and the heated air is blown into the air-conditioning space. The high-pressure liquid refrigerant that has passed through the usage heat exchanger 32 is decompressed in the usage expansion valve 36. The decompressed liquid refrigerant is sent to the heat source unit 10 via the connection pipe 2 and flows into the liquid refrigerant pipe 28d. The refrigerant flowing through the liquid refrigerant pipe 28d is decompressed in the heat source expansion valve 18 to near the suction pressure of the compressor 12, becomes a refrigerant in a gas-liquid two-phase state, and flows into the heat source heat exchanger 16. The low-pressure gas-liquid two-phase state refrigerant flowing into the heat source heat exchanger 16 exchanges heat with the air around the heat source unit 10 supplied by the heat source fan 22 and evaporates to become low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant flows into the accumulator 20 via the flow path switching valve 14. The low-pressure gaseous refrigerant flowing into the accumulator 20 is sucked into the compressor 12 again.

[0053] (2-5-3) Refrigerant leakage prevention function When the refrigerant sensor 38 of any one of the utilization units 30 detects refrigerant leakage, the control unit 70 fully closes the shut-off valve 52 of the shut-off valve unit 50 associated with the utilization unit 30 (hereinafter referred to as the leakage utilization unit) in which the refrigerant sensor 38 has detected refrigerant leakage. Further, when the refrigerant sensor 38 of any one of the utilization units 30 detects refrigerant leakage, the control unit 70, together with the utilization expansion valve 36 of the leakage utilization unit and through the gas pipe GP, closes the utilization expansion valves 36 of a plurality of utilization units 30 (hereinafter referred to as the utilization units of the leakage group) that are connected to the heat source unit 10 via the shut-off valve 52 of the shut-off valve unit 50 associated with the leakage utilization unit. For example, in the example of FIG. 1, since the three utilization units 30 (all utilization units 30) are connected to the heat source unit 10 via the shut-off valve 52 of one shut-off valve unit 50, the control unit 70 fully closes the utilization expansion valves 36 of all the utilization units 30. Thereby, the inflow of refrigerant from the heat source unit 10 to the leakage utilization unit and the utilization units of the leakage group through the communication pipes 2 and 4 is blocked.

[0054] Regarding the signal flow at this time, it is also conceivable that a refrigerant leakage report is sent from the utilization control unit 72 of the leakage utilization unit to the heat source control unit 74 of the heat source unit 10, and a closing command for the utilization expansion valve 36 is sent from the heat source control unit 74 to the utilization control unit 72 of the utilization units of the leakage group, and a closing command for the shut-off valve 52 is sent to the valve control unit 76 of the shut-off valve unit 50. However, in such a signal flow, it may take time until the shut-off valve 52 of the shut-off valve unit 50 and the utilization expansion valves 36 of the utilization units of the leakage group are closed.

[0055] Therefore, here, as shown in FIG. 3, the utilization expansion valves 36 of the utilization units of the leakage group are closed in the signal flow.

[0056] First, when the refrigerant sensor 38 of the leakage utilization unit (referred to as utilization unit A in FIG. 3) detects refrigerant leakage, it sends a signal indicating the refrigerant leakage to the utilization control unit 72 (an example of the controller in the claims) of the utilization unit A where the refrigerant sensor 38 is provided.

[0057] Upon receiving this, the utilization control unit 72 of utilization unit A sends a closing command for the shut-off valve 52 to the valve control unit 76 of the shut-off valve unit 50. Also, the utilization control unit 72 of utilization unit A notifies the utilization control units 72 of the utilization units in the leakage group (utilization units B and C in FIG. 3) that refrigerant leakage has occurred in utilization unit A. In other words, the utilization control unit 72 of utilization unit A sends a closing command for the utilization expansion valve 36 to the utilization control units 72 of utilization units B and C. Furthermore, the utilization control unit 72 of utilization unit A fully closes the utilization expansion valve 36 of utilization unit A. Also, the utilization control unit 72 of utilization unit A stops the operation of utilization unit A (stops the operation of the utilization fan 34).

[0058] Upon receiving the notification of refrigerant leakage from utilization unit A (in other words, the closing command for the utilization expansion valve 36), the utilization control units 72 of utilization units B and C fully close the utilization expansion valves 36 of utilization units B and C respectively. Also, upon receiving the notification of refrigerant leakage from utilization unit A (in other words, the closing command for the utilization expansion valve 36), the utilization control units 72 of utilization units B and C stop the operation of the utilization fans 34 of utilization units B and C respectively.

[0059] Also, the utilization control unit 72 of utilization unit A notifies the heat source control unit 74 of the heat source unit 10 that refrigerant leakage has occurred in utilization unit A. For example, in the example of FIG. 1, when refrigerant leaks in one utilization unit 30, the operation of all utilization units 30 stops, so the heat source control unit 74 of the heat source unit 10 also stops the operation of the heat source unit 10.

[0060] (3) Features (3-1) An air conditioner 100 as an example of a refrigeration cycle apparatus includes a heat source unit 10, a plurality of user units 30, a gas pipe GP, and a shutoff valve 52 as an example of a first shutoff valve. The heat source unit 10 has a compressor 12 and a heat source heat exchanger 16. Each of the plurality of user units 30 has a user heat exchanger 32. The gas pipe GP connects the compressor 12 of the heat source unit 10 and the user heat exchangers 32 of the plurality of user units 30. The gas pipe GP (including the communication pipe 4, the gas refrigerant pipe 28e, and the suction pipe 28a or the discharge pipe 28b) includes a first pipe 4a extending from the heat source unit 10, a second pipe 4b extending from the user unit 30, and a branch portion 4c that branches the first pipe 4a into a plurality of second pipes 4b. The shutoff valve 52 is disposed in the gas pipe GP closer to the heat source unit 10 than the branch portion 4c. Each user unit 30 has an adjustable-opening user expansion valve 36 provided in a liquid pipe LP (including a pipe connecting the liquid end of the user heat exchanger 32 and the communication pipe 2, the communication pipe 2, and the liquid refrigerant pipe 28d) that connects the user heat exchanger 32 of the user unit 30 and the heat source heat exchanger 16 of the heat source unit 10.

[0061] In the air conditioner 100, a common shutoff valve 52 for the plurality of user units is provided in the gas pipe GP, and an adjustable-opening user expansion valve 36 (a shutoff valve also used as an expansion valve) is provided for each user unit 30. Therefore, in the air conditioner 100, the number of components can be reduced while being able to respond to refrigerant leakage from the user unit 30.

[0062] (3-2) The air conditioner 100, each user unit 30 has a refrigerant sensor 38. When the refrigerant sensor 38 of one user unit 30 detects refrigerant leakage, the shutoff valve 52 corresponding to the leaking user unit (of the shutoff valve unit 50) and the user expansion valves 36 of the plurality of user units 30 connected to the heat source unit 10 via this shutoff valve 52 through the gas pipe GP are closed.

[0063] In this air conditioner 100, while reducing the number of components, it is possible to suppress the occurrence of a situation where the concentration of leaked refrigerant becomes high in the space where the user unit 30 is installed.

[0064] (3-3) In the air conditioner 100, the usage unit 30 has a usage control unit 72 as an example of a controller. When the refrigerant sensor 38 of each usage unit 30 detects refrigerant leakage, it transmits a signal to the usage control unit 72 of the usage unit 30 in which the refrigerant sensor 38 is provided. The usage control unit 72 of the usage unit 30 (leakage usage unit) in which the refrigerant sensor 38 that has detected refrigerant leakage is provided transmits a closing command for the usage expansion valve 36 to the usage control unit 72 of the other usage units 30 (usage units of the leakage group) that are connected to the heat source unit 10 via the shut-off valve 52 by the gas pipe GP together with the usage unit 30 in which the leakage is detected.

[0065] In the air conditioner 100, since the usage unit 30 receives a closing command for the usage expansion valve 36 from the usage unit 30 arranged in the vicinity without going through the heat source unit 10, it is possible to quickly cut off the inflow of refrigerant from the heat source unit 10 to the usage unit 30 when refrigerant leakage occurs.

[0066] (3-4) In the air conditioner 100, when the usage unit 30 receives a closing command for the usage expansion valve 36, it stops operating.

[0067] In this air conditioner 100, in addition to the leakage usage unit, since the operation of the usage units 30 of the leakage group (particularly the operation of the usage fan 34) is stopped, it is easy to suppress the situation where the refrigerant flowing out from the usage unit 30 diffuses into the space where the usage unit 30 is installed.

[0068] (4) Modification (4-1) Modification 1A In the above embodiment, all the usage units 30 share one shut-off valve unit 50, but the air conditioner 100 is not limited to such a mode.

[0069] For example, as shown in FIG. 4, the air conditioner 100 includes a plurality of shut-off valve units 50, and two or more of the plurality of usage units 30 may share each shut-off valve unit 50. In the case of the embodiment shown in FIG. 4, some of the plurality of shut-off valve units 50 may be dedicated to one usage unit 30.

[0070] For example, in FIG. 4, it is assumed that the air conditioner 100 has a plurality of groups of usage units 30 including a plurality of usage units 30 (first to Nth groups). One shut-off valve unit 50 is associated with the usage units 30 in each group.

[0071] In this case, for example, it is assumed that one refrigerant sensor 38 of the usage units 30 in the first group detects refrigerant leakage. At this time, the shut-off valve 52 of the shut-off valve unit 50 corresponding to the usage units 30 in the first group is fully closed, and the expansion valves 36 of all the usage units 30 in the first group are also fully closed.

[0072] At this time, if refrigerant leakage is not detected in the usage units 30 of the second to Nth groups, the operation of the heat source unit 10 and the usage units 30 of the second to Nth groups may be continued.

[0073] <Second Embodiment> The air conditioner 100A of the second embodiment will be described with reference to the schematic configuration diagrams of FIGS. 5 to 6.

[0074] The main difference between the air conditioner 100A of the second embodiment and the air conditioner 100 of the first embodiment is that the air conditioner 100A includes a plurality of groups of usage units 30 including a plurality of usage units 30, the usage units 30 in each group can individually select cooling operation and heating operation, and it has an intermediate unit 150 as an example of a shut-off valve unit.

[0075] Since the air conditioner 100A of the second embodiment has many similarities with the air conditioner 100 of the first embodiment, the differences will be mainly described here, and the description of the common points will be omitted unless particularly necessary.

[0076] (1) Overall Outline As an example of a refrigeration cycle device, an air conditioner 100A mainly includes one heat source unit 110, a plurality of user units 30, a plurality of intermediate units 150 for switching the flow of refrigerant between the heat source unit 10 and the user units 30, and connection pipes connecting between the heat source unit 110, the intermediate units 150, and the user units 30. In the air conditioner 100A, one intermediate unit 150 is shared by a plurality of user units 30. A plurality of user units 30 sharing the intermediate unit 150 are called a group of user units 30. In the example of FIG. 6, the air conditioner 100A has two intermediate units 150, and the user units 30 include user units 30 of group A sharing one intermediate unit 150 (150A) and user units 30 of group B sharing the other intermediate unit 150 (150B).

[0077] In the air conditioner 100A, the heat source unit 110, the intermediate unit 150, and the user unit 30 are connected via connection pipes, thereby constituting a refrigerant circuit 190.

[0078] The connection pipes include a liquid connection pipe 102a, a suction gas connection pipe 102b, a high and low pressure gas connection pipe 102c, a first connection pipe 102d, a second connection pipe 102e, a third connection pipe 102f, and a connection pipe 104b.

[0079] (2) Detailed Configuration (2-1) Heat Source Unit The heat source unit 110 will be described with reference to FIG. 5. FIG. 5 is a refrigerant circuit diagram inside the heat source unit 110 of the air conditioner 100A.

[0080] The heat source unit 110 is installed on the rooftop or in the machine room of the building where the air conditioner 100 is installed. The heat source unit 110 mainly includes a first gas-side shut-off valve 119a, a second gas-side shut-off valve 119b, a liquid-side shut-off valve 119c, an accumulator 20, a compressor 12, a first flow path switching valve 14a, a second flow path switching valve 14b, a third flow path switching valve 14c, a heat source heat exchanger 116, a first heat source expansion valve 118a, and a second heat source expansion valve 118b. A part of the refrigerant circuit 190 is formed by connecting these devices via refrigerant pipes. The heat source unit 110 also includes a heat source fan 22 and a heat source control unit 74.

[0081] The first gas-side shut-off valve 119a, the second gas-side shut-off valve 119b, and the liquid-side shut-off valve 119c are manual valves that are opened and closed during refrigerant filling or pump-down. One end of the first gas-side shut-off valve 119a is connected to the suction gas communication pipe 102b, and the other end is connected to the refrigerant pipe extending to the accumulator 20. One end of the second gas-side shut-off valve 119b is connected to the high and low pressure gas communication pipe 102c, and the other end is connected to the refrigerant pipe extending to the second flow path switching valve 14b. One end of the liquid-side shut-off valve 119c is connected to the liquid communication pipe 102a, and the other end is connected to the refrigerant pipe extending to the first heat source expansion valve 118a or the second heat source expansion valve 118b.

[0082] The accumulator 20 is the same device as the accumulator 20 in the first embodiment. The accumulator 20 is disposed between the first gas-side shut-off valve 119a and the compressor 12.

[0083] The compressor 12 is the same device as the compressor 12 in the first embodiment. A detailed description of the compressor 12 is omitted.

[0084] The first flow path switching valve 14a, the second flow path switching valve 14b, and the third flow path switching valve 14c (hereinafter collectively referred to as "flow path switching valve 14A") are four-way switching valves that switch the flow of the refrigerant according to the situation (see the solid and dashed lines in FIG. 5). A discharge pipe of the compressor 12 or a branch pipe extending from the discharge pipe is connected to the refrigerant inlet of the flow path switching valve 14A. The flow path switching valve 14A is configured such that the flow of the refrigerant in one refrigerant flow path is blocked, and in effect, functions as a three-way valve. How the flow path switching valves 14a, 14b, and 14c control the flow direction of the refrigerant according to the operation of the air conditioner 100A will be described together in the description of the refrigerant flow in the air conditioner 100A.

[0085] The heat source heat exchanger 116 has the same configuration as the heat source heat exchanger 16 of the first embodiment, but includes a first heat exchange portion 116a and a second heat exchange portion 116b. One end of the first heat exchange portion 116a is connected to a refrigerant pipe connected to the third flow path switching valve 14c, and the other end is connected to a refrigerant pipe extending to the first heat source expansion valve 118a. One end of the second heat exchange portion 116b is connected to a refrigerant pipe connected to the first flow path switching valve 14a, and the other end is connected to a refrigerant pipe extending to the second heat source expansion valve 118b. The refrigerant passing through the first heat exchange portion 116a and the second heat exchange portion 116b exchanges heat with the air flow generated by the heat source fan 22.

[0086] The first heat source expansion valve 118a and the second heat source expansion valve 118b are, for example, motor-operated valves whose opening degrees can be adjusted. A refrigerant pipe extending from the first heat exchange portion 116a is connected to one end of the first heat source expansion valve 118a, and a refrigerant pipe extending to the liquid-side shut-off valve 119c is connected to the other end. A refrigerant pipe extending from the second heat exchange portion 116b is connected to one end of the second heat source expansion valve 118b, and a refrigerant pipe extending to the liquid-side shut-off valve 119c is connected to the other end. The opening degrees of the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted according to the situation, and the refrigerant passing through the inside is depressurized according to the opening degrees.

[0087] The heat source fan 22 is the same device as the heat source fan 22 in the first embodiment, and an air flow is generated that flows into the heat source unit 110, passes through the heat source heat exchanger 116, and flows out of the heat source unit 110.

[0088] The heat source control unit 74 has the same configuration as the heat source control unit 74 in the first embodiment.

[0089] (2-2) Utilization unit Since the configuration of the utilization unit 30 is the same as that of the utilization unit in the first embodiment, the description thereof is omitted.

[0090] (2-3) Intermediate unit The connecting pipe 104b, the second connecting pipe 102e, the suction gas connecting pipe 102b, and the pipe connecting the gas-side second shut-off valve 119b and the compressor 12, or the connecting pipe 104b, the third connecting pipe 102f, the high-low pressure gas connecting pipe 102c, and the pipe connecting the gas-side first shut-off valve 119a and the compressor 12 constitute the gas pipe GP in the claims. The gas pipe GP connects the compressor 12 of the heat source unit 10 and the utilization heat exchanger 32 of the plurality of utilization units 30. The gas pipe GP includes a first pipe (connecting pipe 104b, second connecting pipe 102e, third connecting pipe 102f) extending from the heat source unit 10, a second pipe 104c extending from the utilization unit 30, and a branch portion 104d that branches the first pipe into a plurality of second pipes 104c. The connecting pipe 104b is the portion of the connecting pipe 4 that connects the heat source unit 10 and the branch portion 104d. The second pipe 104c is the portion of the connecting pipe 4 that connects the utilization unit 30 and the branch portion 104d.

[0091] The intermediate unit 150 is an example of a shut-off valve unit. The intermediate unit 150 is disposed in the first pipe 4a of the connecting pipe 4. The shut-off valve unit 50 has expansion valves 152a, 152b as an example of a first shut-off valve disposed closer to the heat source unit 10 than the branch portion 4c in the gas pipe GP.

[0092] The intermediate unit 150 is arranged at the same location (such as above the ceiling) as the shut-off valve unit 50 in the first embodiment. Here, to avoid duplication of description, the explanation regarding the installation position of the intermediate unit 150 is omitted.

[0093] As shown in FIG. 6, the same number of intermediate units 150 as the number of groups of the utilization units 30 are arranged so as to correspond to a plurality of utilization units 30 (and groups of utilization units 30). Note that a part of the plurality of intermediate units 150 may be associated with one utilization unit 30 instead of a plurality of utilization units 30. Each intermediate unit 150 is arranged between the corresponding group of utilization units 30 and the heat source unit 110, and switches the flow of the refrigerant.

[0094] As shown in FIG. 6, the intermediate unit 150 has two expansion valves 152a and 152b and a valve control unit 76.

[0095] The expansion valves 152a and 152b are provided in the second connection pipe 102e, the third connection pipe 102f, and the communication pipe 104b, and are mechanisms for adjusting the pressure and flow rate of the refrigerant. The expansion valves 152a and 152b are motor-operated valves (electronic expansion valves) whose opening degree can be adjusted. Note that the expansion valves 152a and 152b are valves with little leakage when closed and are also used as shut-off valves in the event of refrigerant leakage. For example, the expansion valves 152a and 152b are valves with a leakage amount of 300 cm 3 / min (air, ΔP = 1.0 MPa) or less when closed.

[0096] The expansion valves 152a and 152b switch the opening and closing of the refrigerant flow path formed between the corresponding utilization unit and the heat source unit 110 according to the situation. The movement of the expansion valves 152a and 152b will be described later together with the operation of the air conditioner 100A. One end of the expansion valve 152a is connected to the communication pipe 104b that branches and extends to the gas ends of a plurality of utilization heat exchangers 32, and the other end is connected to the second connection pipe 102e. One end of the expansion valve 152b is connected to the communication pipe 104b that branches and extends to the gas ends of a plurality of utilization heat exchangers 32, and the other end is connected to the third connection pipe 102f.

[0097] The valve control unit 76 is structurally the same as the valve control unit 76 of the first embodiment. The operation of the control unit 70 including the valve control unit 76 will be described later.

[0098] (2-4) Communication pipe One end of the liquid communication pipe 102a is connected to the liquid-side shut-off valve 119c, and the other end is connected to a plurality of first connection pipes 102d. One end of the first connection pipe 102d is connected to the liquid communication pipe 102a, and the other end branches and is connected to a plurality of user units 30 belonging to one group. One end of the suction gas communication pipe 102b is connected to the gas-side first shut-off valve 119a, and the other end is connected to a second connection pipe 102e extending from each intermediate unit 150. One end of the high and low pressure gas communication pipe 102c is connected to the gas-side second shut-off valve 119b, and the other end side is connected to a third connection pipe 102f extending from each intermediate unit 150. One end of each second connection pipe 102e is connected to the suction gas communication pipe 102b, and the other end is connected to the pipe in which the expansion valve 152a of the intermediate unit 150 is arranged. One end of each third connection pipe 102f is connected to the high and low pressure gas communication pipe 102c, and the other end is connected to the pipe in which the expansion valve 152b of the intermediate unit 150 is arranged. Each communication pipe 104b is connected to the pipe where the pipe in which the expansion valve 152a of the intermediate unit 150 is arranged and the pipe in which the expansion valve 152b is arranged merge. One end of each communication pipe 104b branches at the branch portion 104d, flows through a plurality of second pipes 104c, and is connected to a plurality of user units 30.

[0099] (2-5) Control unit The control unit 70 is composed of a usage control unit 72, a heat source control unit 74, and a valve control unit 76. The control unit 70 controls the operation of the entire air conditioner 100A by causing the control arithmetic units of the usage control unit 72, the heat source control unit 74, and the valve control unit 76 to execute the programs stored in their respective storage devices.

[0100] FIG. 7 is a control block diagram of the air conditioner 100A in the present embodiment.

[0101] As shown in FIG. 7, the control unit 70 is electrically connected to the utilization expansion valves 36, utilization fans 34, and refrigerant sensors 38 of each of the plurality of utilization units 30, the compressor 12, flow path switching valves 14A, heat source expansion valves 118a, 118b, and heat source fans 22 of the heat source unit 10, and the expansion valves 152a, 152b of each of the plurality of intermediate units 150. Further, the control unit 70 is electrically connected to various sensors that measure the temperature and pressure of the refrigerant, the temperature of the air in the air-conditioned space, the outside air temperature, and the like. The control unit 70 controls the operations of various devices included in the air conditioner 100A based on a control signal received by the utilization unit 30 from an operation remote controller (not shown), measurement signals of various sensors, and the like.

[0102] (3) Flow of refrigerant during operation of the air conditioner Regarding the flow of refrigerant during operation of the air conditioner 100A, the case where the utilization unit 30A in group A and the utilization unit 30B in group B in FIG. 6 are in operation will be described according to different situations as an example.

[0103] (3-1) When both the utilization unit 30A and the utilization unit 30B perform cooling operation When both the plurality of utilization units 30A and the plurality of utilization units 30B perform cooling operation, in the intermediate unit 150A corresponding to the plurality of utilization units 30A and the intermediate unit 150B corresponding to the plurality of utilization units 30B, the expansion valve 152a is fully opened and the expansion valve 152b is set to the minimum opening degree. Further, the opening degrees of the utilization expansion valves 36 of the plurality of utilization units 30A and the plurality of utilization units 30B are appropriately adjusted, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are fully opened.

[0104] The flow of the refrigerant in the refrigerant circuit 190 will be described. When the operation of the compressor 12 is started, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The compressed high-pressure gas refrigerant flows into the heat source heat exchanger 116 through the discharge pipe, the first flow path switching valve 14a, the third flow path switching valve 14c, etc. and condenses. The refrigerant that has passed through the heat source heat exchanger 116 passes through the liquid side shut-off valve 119c and flows into the liquid connection pipe 102a. The refrigerant that has passed through the liquid connection pipe 102a reaches the first connection pipe 102d and flows into the plurality of usage units 30A and the plurality of usage units 30B.

[0105] The refrigerant that has reached the plurality of usage units 30A or the plurality of usage units 30B flows into the usage expansion valve 36 and is depressurized. The depressurized refrigerant flows into each usage heat exchanger 32 and evaporates. The refrigerant that has passed through each usage heat exchanger 32 flows through the connection pipe 104b into the pipe where the expansion valve 152a of the intermediate units 150A, 150B is arranged, and reaches the second connection pipe 102e. The refrigerant that has reached the second connection pipe 102e flows into the heat source unit 110 through the suction gas connection pipe 102b and is sucked into the compressor 12 again.

[0106] (3-2) When both the usage unit 30A and the usage unit 30B perform heating operation When both the plurality of usage units 30A and the plurality of usage units 30B perform heating operation, in the intermediate units 150A and 150B, the expansion valve 152a is set to the minimum opening degree, and the expansion valve 152b is set to the fully open state. Also, the usage expansion valves 36 of the plurality of usage units 30A and the plurality of usage units 30B are set to the fully open state, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted in opening degree as appropriate.

[0107] The flow of the refrigerant in the refrigerant circuit 190 will be described. When the operation of the compressor 12 is started, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The compressed high-pressure gas refrigerant flows into the high and low pressure gas connection pipe 102c through the discharge pipe and the second flow path switching valve 14b or the like. The refrigerant that has passed through the high and low pressure gas connection pipe 102c reaches the third connection pipe 102f. The refrigerant that has reached the third connection pipe 102f flows into the pipe in the intermediate unit 150A or 150B where the expansion valve 152b is disposed, and then passes through the connection pipe 104b and reaches a plurality of user units 30A or a plurality of user units 30b.

[0108] The refrigerant that has reached a plurality of user units 30A or a plurality of user units 30B flows into each user heat exchanger 32 and condenses. The refrigerant that has passed through each user heat exchanger 32 flows into the first connection pipe 102d. The refrigerant that has reached the first connection pipe 102d reaches the heat source unit 110 through the liquid connection pipe 102a.

[0109] The refrigerant that has reached the heat source unit 110 passes through the first heat source expansion valve 118a or the second heat source expansion valve 118b and is decompressed according to the opening degree. The decompressed refrigerant flows into the heat source heat exchanger 116 and evaporates. The refrigerant that has passed through the heat source heat exchanger 116 is sucked into the compressor 12 again through the first flow path switching valve 14a or the third flow path switching valve 14c.

[0110] (3-3) When either one of the user unit 30A and the user unit 30B performs a cooling operation and the other performs a heating operation For example, when a plurality of user units 30A perform a cooling operation and a plurality of user units 30B perform a heating operation, in the intermediate unit 150A, the expansion valve 152a is fully opened and the expansion valve 152b is set to the minimum opening degree. Also, the utilization expansion valves 36 of the plurality of user units 30A are adjusted to appropriate opening degrees. In the intermediate unit 150B, the expansion valve 152a is set to the minimum opening degree and the expansion valve 152b is fully opened. Also, the utilization expansion valves 36 of the plurality of user units 30B are fully opened. Then, the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted to appropriate opening degrees.

[0111] The flow of the refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 is operated, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The high-pressure gaseous refrigerant compressed by the compressor 12 flows into the high-low pressure gas connecting pipe 102c through the discharge pipe, the second flow path switching valve 14b, etc. The refrigerant that has passed through the high-low pressure gas connecting pipe 102c reaches the third connecting pipe 102f. The refrigerant that has passed through the third connecting pipe 102f flows into the intermediate unit 150B, flows through the pipe where the expansion valve 152b is arranged, and then flows into the connecting pipe 104b.

[0112] The refrigerant that has passed through the connecting pipe 104b reaches the plurality of utilization units 30B, flows into the utilization heat exchanger 32, and condenses. The condensed refrigerant flows into the first connecting pipe 102d that is connected to the plurality of utilization units 30A through the first connecting pipe 102d, and reaches the plurality of utilization units 30A.

[0113] The refrigerant that has reached the plurality of utilization units 30A flows into the utilization expansion valve 36 of each utilization unit A and is depressurized according to the opening degree. The depressurized refrigerant flows into the utilization heat exchanger 32 and evaporates. The evaporated refrigerant passes through the connecting pipe 104b, reaches the intermediate unit 150A, flows into the pipe where the expansion valve 152a is arranged, and reaches the second connecting pipe 102e.

[0114] The refrigerant that has reached the second connecting pipe 102e flows into the heat source unit 110 through the suction gas connecting pipe 102b and is sucked into the compressor 12 again.

[0115] (3-4) Refrigerant leakage prevention function When the refrigerant sensor 38 of any one of the usage units 30 detects refrigerant leakage, the control unit 70 fully closes the expansion valves 152a and 152b of the intermediate unit 150 associated with the usage unit 30 (hereinafter referred to as the leakage usage unit) in which the refrigerant sensor 38 has detected refrigerant leakage. Further, when the refrigerant sensor 38 of any one of the usage units 30 detects refrigerant leakage, the control unit 70 closes the usage expansion valve 36 of the leakage usage unit and, via the gas pipe GP, together with the leakage usage unit, closes the usage expansion valves 36 of a plurality of usage units 30 (hereinafter referred to as the usage units of the leakage group) connected to the heat source unit 10 via the shut-off valve 52 of the shut-off valve unit 50 associated with the leakage usage unit.

[0116] For example, in the example of FIG. 6, when refrigerant leakage is detected in one of the usage units 30A of group A, since the two usage units 30A belonging to group A are connected to the heat source unit 10 via the expansion valves 152a and 152b of one intermediate unit 150A, the control unit 70 fully closes the usage expansion valves 36 of the two usage units 30A. As a result, the inflow of refrigerant through the communication pipe from the heat source unit 110 to the leakage usage unit and the usage units of the leakage group (to the usage unit 30A of group A) is blocked.

[0117] Note that also in the second embodiment, the usage expansion valve 36 of the usage unit 30 is closed in the signal flow as shown in FIG. 8.

[0118] First, when the refrigerant sensor 38 of the leakage usage unit (referred to as usage unit A in FIG. 8) belonging to group A detects refrigerant leakage, a signal notifying of the refrigerant leakage is transmitted to the usage control unit 72 (an example of the controller in the claims) of the usage unit A in which the refrigerant sensor is provided.

[0119] In response to this, the usage control unit 72 of usage unit A sends a closing command for the expansion valves 152a and 152b to the valve control unit 76 of the intermediate unit 150A. Also, the usage control unit 72 of usage unit A notifies the usage control units 72 of usage units other than usage unit A belonging to group A (usage units B and C in FIG. 8) that refrigerant leakage has occurred in usage unit A. In other words, the usage control unit 72 of usage unit A sends a closing command for the usage expansion valve 36 to the usage control units 72 of usage units B and C. Furthermore, the usage control unit 72 of usage unit A fully closes the usage expansion valve 36 of usage unit A. Also, the usage control unit 72 of usage unit A stops the operation of usage unit A (stops the operation of the usage fan 34).

[0120] Upon receiving the notification of refrigerant leakage from usage unit A (in other words, the closing command for the usage expansion valve 36), the usage control units 72 of usage units B and C fully close the usage expansion valves 36 of usage units B and C, respectively. Also, upon receiving the notification of refrigerant leakage from usage unit A (in other words, the closing command for the usage expansion valve 36), the usage control units 72 of usage units B and C stop the operation of the usage fans 34 of usage units B and C, respectively.

[0121] Also, the usage control unit 72 of usage unit A notifies the heat source control unit 74 of the heat source unit 10 that refrigerant leakage has occurred in usage unit A.

[0122] Here, even if refrigerant is leaking from usage unit A, the usage unit 30B of group B can still operate. However, when all the usage units 30A of group A stop, since the amount of refrigerant to be circulated and the like change, the heat source control unit 74 of the heat source unit 10 adjusts the rotation speed of the compressor 12, the opening degree of the heat source expansion valves 118a and 118b, etc.

[0123] Note that when refrigerant leakage is detected in any of the usage units 30, the control unit 70 may stop the operation of the compressor 12 and also stop the cooling operation / heating operation in usage units 30 other than the usage unit 30 in which refrigerant leakage has been detected.

[0124] (4) Features (4-1) As an example of a refrigeration cycle device, an air conditioner 100A includes a heat source unit 110, a plurality of usage units 30, a gas pipe GP, and expansion valves 152a and 152b as an example of a first shut-off valve. The heat source unit 110 has a compressor 12 and a heat source heat exchanger 118. Each of the plurality of usage units 30 has a usage heat exchanger 32. The gas pipe GP connects the compressor 12 of the heat source unit 110 and the usage heat exchangers 32 of the plurality of usage units 30. The gas pipe GP includes a first pipe (communication pipe 104b, second connection pipe 102e, third connection pipe 102f) extending from the heat source unit 110, a second pipe 104c extending from the usage unit 30, and a branch portion 104d that branches the first pipe into a plurality of second pipes 104c. The expansion valves 152a and 152b are arranged near the heat source unit 110 from the branch portion 104d in the gas pipe GP. Each usage unit 30 has an adjustable-opening usage expansion valve 36 provided in a liquid pipe that connects the usage heat exchanger 32 of the usage unit 30 and the heat source heat exchanger 118 of the heat source unit 110.

[0125] In the air conditioner 100A, expansion valves 152a and 152b are provided as a first shut-off valve common to the plurality of usage units 30 in the gas pipe GP, and an adjustable-opening usage expansion valve 36 (a shut-off valve also used as an expansion valve) is provided for each usage unit 30. Therefore, in the air conditioner 100A, while reducing the number of parts, it is possible to respond to refrigerant leakage from the usage unit 30.

[0126] (4-2) In the air conditioner 100A, the expansion valves 152a and 152b are adjustable-opening flow control valves.

[0127] In this air conditioner 100A, the expansion valves 152a and 152b as the first shut-off valve can be used not only as a shut-off valve but also for flow control purposes, and the number of parts can be reduced.

[0128] (4-3) In the air conditioner 100A, each user unit 30 has a refrigerant sensor 38. When the refrigerant sensor 38 of one user unit 30 detects refrigerant leakage, the expansion valves 152a and 152b (of the intermediate unit 150) corresponding to the leaking user unit and the utilization expansion valves 36 of a plurality of user units 30 connected to the heat source unit 110 via these expansion valves 152a and 152b through the gas pipe GP are closed.

[0129] In this air conditioner 100A, while reducing the number of parts, it is possible to suppress the occurrence of a situation where the concentration of leaked refrigerant in the space where the user unit 30 is installed becomes high.

[0130] (4-4) In the air conditioner 100A, the user unit 30 has a utilization control unit 72 as an example of a controller. When the refrigerant sensor of each user unit 30 detects refrigerant leakage, it sends a signal to the utilization control unit 72 of the user unit 30 in which the refrigerant sensor is provided. The utilization control unit 72 of the user unit 30 in which the refrigerant sensor 38 that has detected refrigerant leakage is provided sends a closing command for the utilization expansion valve 36 to the utilization control unit 72 of other user units 30 connected to the heat source unit 110 via the expansion valves 152a and 152b through the gas pipe GP together with the user unit 30 in which the leakage has been detected.

[0131] In the air conditioner 100A, since the user unit 30 receives a closing command for the utilization expansion valve 36 from a neighboring user unit 30 without passing through the heat source unit 110, it is possible to quickly cut off the inflow of refrigerant from the heat source unit 110 to the user unit 30 when refrigerant leakage occurs.

[0132] (4-5) In the air conditioner 100A, when the user unit 30 receives a closing command for the utilization expansion valve 36, it stops operating.

[0133] In this air conditioner 100A, since the operation of the utilization unit 30 (particularly the operation of the utilization fan 34) belonging to the group to which the leakage utilization unit belongs and sharing the same shut-off valve unit 50 as the leakage utilization unit is stopped, the situation where the refrigerant flowing out from the utilization unit 30 diffuses into the space where the utilization unit 30 is installed is easily suppressed.

[0134] (5) Modification (5-1) Modification 2A The air conditioner 100 of the first embodiment includes a shut-off valve unit 50 having a shut-off valve 52 and a casing 54 that houses the shut-off valve 52. The air conditioner 100A of the second embodiment includes an intermediate unit 150 having expansion valves 152a and 152b and a casing 154 that houses the expansion valves 152a and 152b. However, it is not essential that the shut-off valve 52 or the expansion valves 152a and 152b be unitized as in the first and second embodiments. The shut-off valve 52 or the expansion valves 152a and 152b may be directly attached to the connecting pipe.

[0135] <Others> As described above, although the embodiments of the present disclosure have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure described in the claims.

Description of Reference Numerals

[0136] 4a First pipe 4b Second pipe 4c Branch portion 10, 110 Heat source unit 12 Compressor 16, 116 Heat source heat exchanger 30 Utilization unit 32 Utilization heat exchanger 36 Utilization expansion valve (second shut-off valve) 38 Refrigerant sensor 52 Shut-off valve (first shut-off valve) 72 Utilization control unit (controller) 100, 100A Air conditioner (refrigeration cycle device) 102e Second connection pipe (first pipe) 102f Third connecting pipe (first pipe) 104b Connecting pipe (first pipe) 104c Second pipe 104d Branch portion 152a, 152b Expansion valve (first shut-off valve) GP Gas pipe LP Liquid pipe

Prior art documents

Patent documents

[0137]

Patent Document 1

Claims

1. A heat source unit (10, 110) having a compressor (12), a heat source heat exchanger (16, 116), and a heat source controller (74); A plurality of user units (30), each having a user heat exchanger (32), a user controller (72), and a refrigerant sensor (38); A first pipe (4a, 104b, 102e, 102f) extending from the heat source unit, a second pipe (4b, 104c) extending from the user unit, and a branch portion (4c, 104d) for branching the first pipe into a plurality of the second pipes, including a gas pipe (GP) connecting the compressor of the heat source unit and the user heat exchangers of the plurality of user units; A first shut-off valve (52, 152a, 152b) disposed in the gas pipe near the heat source unit from the branch portion; Comprising; Each of the user units has an adjustable-opening second shut-off valve (36) provided in a liquid pipe (LP) connecting the user heat exchanger of the user unit and the heat source heat exchanger of the heat source unit; When the refrigerant sensor of one of the user units detects refrigerant leakage, the first shut-off valve and the second shut-off valves of the plurality of user units connected to the heat source unit via the first shut-off valve by the gas pipe are closed; When the refrigerant sensor of each user unit detects refrigerant leakage, it transmits a signal to the user controller of the user unit in which the refrigerant sensor is provided; The user controller of the user unit in which the refrigerant sensor that has detected refrigerant leakage is provided transmits a closing command for the second shut-off valve to the user controllers of the other user units connected to the heat source unit via the first shut-off valve by the gas pipe, together with the user unit in which the leakage has been detected, without passing through the heat source controller; A refrigeration cycle apparatus (100, 100A).

2. The first shut-off valve (152a, 152b) is a flow rate adjustment valve with adjustable opening degree, The refrigeration cycle apparatus (100A) according to Claim 1.

3. When the user unit receives a closing command for the second shut-off valve, it stops operation, The refrigeration cycle apparatus according to Claim 1 or 2.

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