JP7701640B2 - Refrigeration Cycle Equipment - Google Patents

Description

This disclosure relates to a refrigeration cycle device.

As shown in Patent Document 1 (Patent No. 6927315), a refrigeration cycle device is known in which a shutoff valve is provided in each of a number of utilization units having a utilization heat exchanger and a utilization expansion valve, and the shutoff valve is closed in the event of a refrigerant leak.

In such a refrigeration cycle device, a large number of shutoff valves are required in the refrigerant piping depending on the number of utilization units.

The refrigeration cycle device of the first aspect includes a heat source unit, a plurality of utilization units, a gas pipe, and a first shutoff 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 to 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 branching section that branches the first pipe into a plurality of second pipes. The first shutoff valve is disposed in the gas pipe closer to the heat source unit than the branching section. Each utilization unit has a second shutoff valve with adjustable opening 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.

In the refrigeration cycle device of the first aspect, a first shutoff valve common to multiple utilization units is provided in the gas piping, and a second shutoff valve (a shutoff valve that is also used as an expansion valve) with an adjustable opening is provided for each utilization unit. Therefore, the refrigeration cycle device of the first aspect can respond to refrigerant leakage from the utilization units while reducing the number of parts.

The refrigeration cycle device of the second aspect is the refrigeration cycle device of the first aspect, in which the first shutoff valve is a flow control valve whose opening is adjustable.

In this refrigeration cycle device, the first shutoff valve can be used not only as a shutoff valve but also for flow rate adjustment purposes, which reduces the number of parts.

The refrigeration cycle device of the third aspect is the refrigeration cycle device of the first or second aspect, and each utilization unit further has a refrigerant sensor. When the refrigerant sensor of one utilization unit detects a refrigerant leak, the first shutoff valve and the second shutoff valves of the utilization units connected to the heat source unit via the first shutoff valve by gas piping are closed.

The refrigeration cycle device of the third aspect can reduce the number of parts while suppressing the occurrence of a situation in which the concentration of leaking refrigerant becomes high in the space in which the utilization unit is installed.

The refrigeration cycle device of the fourth aspect is the refrigeration cycle device of the third aspect, in which the utilization unit further includes a controller. When the refrigerant sensor of each utilization unit detects a refrigerant leak, it transmits a signal to the controller of the utilization unit in which the refrigerant sensor is provided. The controller of the utilization unit in which the refrigerant sensor that detected the refrigerant leak is provided transmits a command to close the second shutoff valve to the controller of the other utilization unit that is connected to the heat source unit via the first shutoff valve by gas piping together with the utilization unit in which the leak was detected.

In the refrigeration cycle device of the fourth aspect, the utilization unit receives a command to close the second shutoff valve from a utilization unit located nearby without going through the heat source unit, so that the flow of refrigerant from the heat source unit to the utilization unit can be shut off early in the event of a refrigerant leak.

The refrigeration cycle device of the fifth aspect is the refrigeration cycle device of the fourth aspect, in which the utilization unit stops operation when it receives a command to close the second shutoff valve.

In this refrigeration cycle device, the operation of the utilization unit is stopped, which helps prevent the refrigerant flowing out of the utilization unit from diffusing into the space in which the utilization unit is installed.

1 is a schematic configuration diagram of an air conditioner according to a first embodiment. FIG. FIG. 2 is a control block diagram of the air conditioner of FIG. 1 . 4 is a sequence chart illustrating the exchange of signals between control units and the operation of each unit when a refrigerant sensor in one utilization unit of the air conditioner in FIG. 1 detects a leak. 13 is a diagram for explaining the operation of the air conditioner 100 in the case where a refrigerant leak is detected in one of the utilization units in the modification A. FIG. FIG. 11 is a diagram of a refrigerant circuit in a heat source unit of an air conditioner according to a second embodiment. FIG. 11 is a refrigerant circuit diagram of a portion other than a heat source unit of an air conditioner according to a second embodiment. FIG. 11 is a control block diagram of an air conditioner according to a second embodiment. 13 is a sequence chart illustrating the exchange of signals between control units and the operation of each unit when a refrigerant sensor in one utilization unit of an air conditioner according to a second embodiment detects a leak.

An embodiment of the refrigeration cycle device will be described with reference to the drawings.

First Embodiment
(1) Overall Configuration A description will be given of an air conditioner 100 which is a first embodiment of a refrigeration cycle device. 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.

The air conditioner 100 of the first embodiment will be described with reference to the schematic diagram in FIG. 1.

The air conditioner 100 is a device that conditions multiple air-conditioned spaces within a building. The air conditioner 100 mainly has a heat source unit 10, multiple utilization units 30, one shutoff valve unit 50 shared by the multiple utilization units 30, and a control unit 70 (see FIG. 1). Note that the number of utilization units 30 depicted in FIG. 1 does not limit the number of utilization units 30 that the air conditioner 100 has.

The heat source unit 10 and the utilization unit 30 are connected by the communication pipes 2 and 4 as shown in FIG. 1. The heat source unit 10 and the utilization unit 30 are connected by the communication pipes 2 and 4 to form a refrigerant circuit 90 including a compressor 12, a heat source heat exchanger 16, a heat source expansion valve 18, a utilization expansion valve 36, a utilization heat exchanger 32, etc., which will be described later. The shutoff valve unit 50 is provided in the communication pipe 4 as shown in FIG. 1. The communication pipe 4 is a gas communication pipe through which the refrigerant flows from the utilization unit 30 to the heat source unit 10 during cooling operation, and from the heat source unit 10 to the utilization unit 30 during heating operation. The control unit 70 controls the operation of each part of the air conditioner 100.

(2) Detailed Configuration (2-1) Usage Unit The usage unit 30 is installed in the air-conditioned space to be air-conditioned. The usage unit 30 is, for example, a ceiling-embedded type, a ceiling-suspended type, a wall-mounted type, a floor-standing type, etc. In this embodiment, the following description will be given using the usage unit 30 as a ceiling-embedded type.

Each utilization unit 30 mainly has 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.

In the utilization heat exchanger 32, heat exchange takes place 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 multiple heat transfer fins and multiple heat transfer tubes.

The utilization fan 34 supplies 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).

The utilization expansion valve 36 is an example of a second shutoff valve. Here, the pipe connecting the liquid end of the utilization heat exchanger 32 and the connection pipe 2, the connection 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 this embodiment, the utilization expansion valve 36 is provided in the pipe connecting the connection 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 degree can be adjusted. The utilization expansion valve 36 is also used as a shutoff valve when refrigerant leaks, and is a valve with a small leakage amount when the valve is closed. For example, the utilization expansion valve 36 is a valve with a leakage amount of 300 cm ³ /min (air, ΔP=1.0 MPa) or less when the valve is closed.

The refrigerant sensor 38 is a sensor that detects refrigerant leakage. The refrigerant sensor 38 is installed, for example, near the utilization heat exchanger 32.

The usage control unit 72 has a control and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs a predetermined arithmetic process in accordance with the program, thereby working together 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 operation of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

(2-2) Heat Source Unit The heat source unit 10 is installed on the rooftop or in a machine room of a building in which 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.

The suction pipe 28a connects the flow path switching valve 14 and the suction side of the compressor 12. The 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 connecting pipe 2. The heat source expansion valve 18 is provided in the liquid refrigerant pipe 28d. The liquid stop valve 24 is provided at the connection between the liquid refrigerant pipe 28d and the connecting pipe 2. The gas refrigerant pipe 28e connects the flow path switching valve 14 and the connecting pipe 4. The gas stop valve 26 is provided at the connection between the gas refrigerant pipe 28e and the connecting pipe 4. The liquid stop valve 24 and the gas stop valve 26 are valves that are opened and closed manually.

The compressor 12 draws in low-pressure refrigerant in the refrigeration cycle from the suction pipe 28a, compresses the refrigerant using a compression mechanism (not shown), and discharges the compressed high-pressure refrigerant in the refrigeration cycle to the discharge pipe 28b. The compressor 12 is, for example, a rotary or scroll type volumetric compressor. 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.

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 lines in the flow path switching valve 14 in 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 dashed lines in the flow path switching valve 14 in FIG. 1. The flow path switching valve 14 is, for example, a four-way switching valve.

During cooling operation, the flow path switching valve 14 sets the refrigerant flow path 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 then 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.

During heating operation, the flow path switching valve 14 sets the refrigerant flow path 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, utilization expansion valve 36, heat source expansion valve 18, and 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.

The heat source heat exchanger 16 exchanges heat 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 multiple heat transfer fins and multiple heat transfer tubes.

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 electrically operated valve (electronic expansion valve) whose opening can be adjusted.

The accumulator 20 is a container that is provided in the suction pipe 28a and has a gas-liquid separation function that separates the refrigerant that flows in into gas refrigerant and liquid refrigerant. The refrigerant that flows into the accumulator 20 is separated into gas refrigerant and liquid refrigerant, and the gas refrigerant that collects in the upper space flows into the compressor 12.

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).

The heat source control unit 74 has a control and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs a predetermined arithmetic process in accordance with the program, thereby working together with the usage control unit 72 of the usage unit 30 and the valve control unit 76 of the shutoff valve unit 50 to control the operation of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

(2-3) Shutoff 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 exchangers 32 of the multiple 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 branching section 4c that branches the first pipe 4a into multiple second pipes 4b. The first pipe 4a is a portion of the communication pipe 4 that connects the heat source unit 10 and the branching section 4c. The second pipe 4b is a portion of the communication pipe 4 that connects the utilization unit 30 and the branching section 4c.

The shutoff valve unit 50 is disposed in the first pipe 4a of the connection pipe 4. The shutoff valve unit 50 has a shutoff valve 52 as an example of a first shutoff valve disposed in the gas pipe GP closer to the heat source unit 10 than the branching portion 4c. One shutoff valve unit 50 is provided corresponding to the multiple utilization units 30. In this embodiment, one shutoff valve unit 50 is provided for the total number of utilization units 30. The shutoff valve unit 50 is a unit that shuts off the flow of refrigerant in the event of a refrigerant leak from the corresponding utilization unit 30, etc.

The shutoff valve unit 50 is disposed, for example, outside the air-conditioned space. For example, the shutoff valve unit 50 is disposed in the attic space of the air-conditioned space or in the underfloor space of the air-conditioned space. The shutoff valve unit 50 is also disposed in the attic space of a corridor adjacent to the air-conditioned space. Note that the installation location of the shutoff valve unit 50 is not limited to the locations exemplified, and may be determined as appropriate.

The shutoff valve unit 50 mainly includes a shutoff valve 52, a casing 54, and a valve control unit 76.

The shutoff valve 52 is a valve that has a small leakage amount when closed. For example, the shutoff valve 52 is a solenoid valve that has a leakage amount of 300 ^cm3 /min (air, ΔP = 1.0 MPa) or less when closed. However, the type of valve is not limited to a solenoid valve, and may be an electrically operated valve whose opening degree can be adjusted.

The casing 54 is a housing that houses the shutoff valve 52. A dew-proofing material is placed inside the casing 54, which prevents condensation from forming around the shutoff valve 52.

The valve control unit 76 has a control arithmetic device and a storage device. The control arithmetic device is a processor such as a CPU and a GPU. The storage device is a storage medium such as a RAM, a ROM, and a flash memory. The control arithmetic device reads out a program stored in the storage device and performs a predetermined arithmetic process in accordance with the program, thereby working together with the usage control unit 72 of the usage unit 30 and the heat source control unit 74 of the heat source unit 10 to control the operation of various devices of the air conditioner 100 as the control unit 70. The functions of the control unit 70 will be described later.

(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 operation of the entire air conditioner 100 by causing the control and arithmetic devices of the usage control unit 72, the heat source control unit 74, and the valve control unit 76 to execute programs stored in their respective storage devices.

Figure 2 is a control block diagram of the air conditioner 100 in this embodiment.

As shown in FIG. 2, the control unit 70 is electrically connected to the utilization expansion valves 36, utilization fans 34, and refrigerant sensors 38 of each of the utilization units 30, the compressor 12, flow path switching valve 14, heat source expansion valve 18, and heat source fan 22 of the heat source unit 10, and the shutoff valves 52 of each of the shutoff valve units 50. The control unit 70 is also 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 operation of various devices of the air conditioner 100 based on control signals received by the utilization units 30 from an operation remote control (not shown) and measurement signals of various sensors, etc.

The control unit 70 mainly performs cooling and heating operations. The control unit 70 also has a function to prevent refrigerant leakage.

(2-5-1) Cooling Operation When the control unit 70 receives a command to perform cooling operation, for example, from an operating remote control via the utilization unit 30, it sets the flow path switching valve 14 to the first state and starts the operation of the compressor 12. In addition, based on the measurement results of sensors that measure the temperature and pressure of the refrigerant, which are provided in the refrigerant circuit 90, it appropriately controls the rotation speed of the motor of the compressor 12 and the openings of the heat source expansion valve 18 and the utilization expansion valve 36. During cooling operation, the shutoff valve 52 is controlled to be fully open.

The flow of refrigerant in the refrigerant circuit 90 will be described. When the compressor 12 starts operating, 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 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, where it exchanges heat with the air around the heat source unit 10 supplied by the heat source fan 22, condenses, and becomes 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 utilization unit 30 is decompressed to near the suction pressure of the compressor 12 in the utilization expansion valve 36, becomes a gas-liquid two-phase refrigerant, and is sent to the utilization heat exchanger 32. The refrigerant in the gas-liquid two-phase state evaporates in the utilization heat exchanger 32 by exchanging heat with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34, and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerant flowing out of the multiple utilization units 30 joins together and is sent to the heat source unit 10 via the communication pipe 4 and the shutoff valve unit 50, and flows into the accumulator 20 via the flow path switching valve 14. The low-pressure gas refrigerant that flows into the accumulator 20 is sucked back into the compressor 12. The temperature of the air supplied to the utilization heat exchanger 32 is lowered by heat exchange with the refrigerant flowing through the utilization heat exchanger 32, and the cooled air is blown out into the air-conditioned space.

(2-5-2) Heating Operation When the control unit 70 receives a command to perform heating operation, for example, from an operating remote control via the utilization unit 30, it sets the flow path switching valve 14 to the second state and starts the operation of the compressor 12. In addition, based on the measurement results of sensors that measure the temperature and pressure of the refrigerant, which are provided in the refrigerant circuit 90, it appropriately controls the rotation speed of the motor of the compressor 12 and the openings of the heat source expansion valve 18 and the utilization expansion valve 36. During heating operation, the shutoff valve 52 is controlled to be fully open.

The flow of refrigerant in the refrigerant circuit 90 will be described. When the compressor 12 is started, low-pressure gas refrigerant is sucked into the compressor 12 and compressed by the compressor 12 to become high-pressure gas refrigerant. The high-pressure gas refrigerant passes through the shutoff valve unit 50, is sent to the utilization heat exchanger 32 via the flow path switching valve 14, and is condensed through heat exchange with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34, becoming high-pressure liquid refrigerant. The temperature of the air supplied to the utilization heat exchanger 32 increases by heat exchange with the refrigerant flowing through the utilization heat exchanger 32, and the heated air is blown out into the air-conditioned space. The high-pressure liquid refrigerant that has passed through the utilization heat exchanger 32 is depressurized in the utilization expansion valve 36. The depressurized liquid refrigerant is sent to the heat source unit 10 via the communication pipe 2 and flows into the liquid refrigerant pipe 28d. The refrigerant flowing through the liquid refrigerant pipe 28d is decompressed to near the suction pressure of the compressor 12 in the heat source expansion valve 18, becomes a gas-liquid two-phase refrigerant, and flows into the heat source heat exchanger 16. The low-pressure gas-liquid two-phase refrigerant that flows 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, evaporates, and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerant flows into the accumulator 20 via the flow path switching valve 14. The low-pressure gas refrigerant that flows into the accumulator 20 is sucked back into the compressor 12.

(2-5-3) Refrigerant Leakage Prevention Function When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the control unit 70 fully closes the shutoff valve 52 of the shutoff valve unit 50 associated with the utilization unit 30 in which the refrigerant sensor 38 has detected a refrigerant leak (hereinafter referred to as the leaking utilization unit). When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the control unit 70 fully closes the utilization expansion valve 36 of the leaking utilization unit and the utilization expansion valves 36 of the utilization units 30 (hereinafter referred to as the utilization units of the leaking group) that are connected to the heat source unit 10 together with the leaking utilization unit by the gas piping GP via the shutoff valve 52 of the shutoff valve unit 50 associated with the leaking utilization unit. 1, three utilization units 30 (all utilization units 30) are connected to the heat source unit 10 via the shutoff valve 52 of one shutoff valve unit 50, so the control unit 70 fully closes the utilization expansion valves 36 of all utilization units 30. This blocks the inflow of refrigerant from the heat source unit 10 to the leaking utilization unit and the utilization units of the leaking group through the connection pipes 2, 4.

In addition, the signal flow at this time may be such that the usage control unit 72 of the leaking usage unit reports the refrigerant leakage to the heat source control unit 74 of the heat source unit 10, the heat source control unit 74 sends a command to close the usage expansion valve 36 to the usage control unit 72 of the usage unit of the leaking group, and a command to close the shutoff valve 52 is sent to the valve control unit 76 of the shutoff valve unit 50. However, with such a signal flow, it may take time for the shutoff valve 52 of the shutoff valve unit 50 and the usage expansion valve 36 of the usage unit of the leaking group to be closed.

Here, the utilization expansion valve 36 of the utilization unit of the leakage group is closed according to the signal flow shown in FIG. 3.

First, when the refrigerant sensor 38 of the leaking utilization unit (referred to as utilization unit A in FIG. 3) detects a refrigerant leak, it sends a signal notifying the refrigerant leak to the utilization control unit 72 (an example of a controller in the claims) of the utilization unit A in which the refrigerant sensor 38 is installed.

The utilization control unit 72 of utilization unit A receives this and transmits a command to close the shutoff valve 52 to the valve control unit 76 of the shutoff valve unit 50. The utilization control unit 72 of utilization unit A also notifies the utilization control units 72 of the utilization units in the leakage group (utilization units B and C in FIG. 3) that a refrigerant leak has occurred in utilization unit A. In other words, the utilization control unit 72 of utilization unit A transmits a command to close 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. The utilization control unit 72 of utilization unit A also stops the operation of utilization unit A (stops the operation of the utilization fan 34).

The utilization control units 72 of utilization units B and C, upon receiving a refrigerant leakage notification from utilization unit A (in other words, a command to close the utilization expansion valve 36), fully close the utilization expansion valves 36 of utilization units B and C, respectively. In addition, the utilization control units 72 of utilization units B and C, upon receiving a refrigerant leakage notification from utilization unit A (in other words, a command to close the utilization expansion valve 36), stop the operation of the utilization fans 34 of utilization units B and C, respectively.

The usage control unit 72 of the usage unit A also notifies the heat source control unit 74 of the heat source unit 10 that a refrigerant leak has occurred in the usage unit A. For example, in the example of FIG. 1, if a refrigerant leak occurs in one usage unit 30, the operation of all usage 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.

(3) Features (3-1)
The air conditioner 100 as an example of a refrigeration cycle device includes a heat source unit 10, a plurality of utilization 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 utilization units 30 has a utilization heat exchanger 32. 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 (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 utilization unit 30, and a branching 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 branching portion 4c. Each utilization unit 30 has an adjustable opening utilization expansion valve 36 provided in a liquid piping LP (including a piping connecting the liquid end of the utilization heat exchanger 32 to the connecting piping 2, the connecting piping 2, and the liquid refrigerant piping 28d) connecting the utilization heat exchanger 32 of that utilization unit 30 to the heat source heat exchanger 16 of the heat source unit 10.

In the air conditioner 100, a shutoff valve 52 common to multiple utilization units is provided in the gas piping GP, and an adjustable utilization expansion valve 36 (a shutoff valve that is also used as an expansion valve) is provided for each utilization unit 30. Therefore, the air conditioner 100 can respond to refrigerant leakage from the utilization unit 30 while reducing the number of parts.

(3-2)
In the air conditioner 100, each utilization unit 30 has a refrigerant sensor 38. When the refrigerant sensor 38 of one utilization unit 30 detects a refrigerant leak, the shutoff valve 52 (of the shutoff valve unit 50) corresponding to the leaking utilization unit and the utilization expansion valves 36 of the utilization units 30 connected to the heat source unit 10 via the shutoff valve 52 by the gas piping GP are closed.

This air conditioner 100 reduces the number of parts while preventing the occurrence of a situation in which the concentration of leaking refrigerant becomes high in the space in which the utilization unit 30 is installed.

(3-3)
In the air conditioner 100, the utilization unit 30 has a utilization control unit 72 as an example of a controller. When the refrigerant sensor 38 of each utilization unit 30 detects a refrigerant leak, it transmits a signal to the utilization control unit 72 of the utilization unit 30 in which the refrigerant sensor 38 is provided. The utilization control unit 72 of the utilization unit 30 in which the refrigerant sensor 38 that detected the refrigerant leak is provided (the leaking utilization unit) transmits a command to close the utilization expansion valve 36 to the utilization control units 72 of the other utilization units 30 (the utilization units of the leaking group) that are connected to the heat source unit 10 via the shutoff valve 52 by the gas piping GP together with the utilization unit 30 in which the leak was detected.

In the air conditioner 100, the utilization unit 30 receives a command to close the utilization expansion valve 36 from a utilization unit 30 located nearby without going through the heat source unit 10, so that the flow of refrigerant from the heat source unit 10 to the utilization unit 30 can be blocked early in the event of a refrigerant leak.

(3-4)
In the air conditioner 100, when the utilization unit 30 receives a command to close the utilization expansion valve 36, it stops operating.

In this air conditioner 100, in addition to the leaking utilization unit, the operation of the utilization units 30 in the leaking group (particularly the operation of the utilization fan 34) is stopped, so that the refrigerant flowing out from the utilization unit 30 is less likely to diffuse into the space in which the utilization unit 30 is installed.

(4) Modifications (4-1) Modification 1A
In the above embodiment, all of the utilization units 30 share one shutoff valve unit 50, but the air conditioner 100 is not limited to this configuration.

For example, as shown in FIG. 4, the air conditioner 100 may include multiple shutoff valve units 50, and two or more of the multiple utilization units 30 may share each shutoff valve unit 50. In the case of an embodiment such as that shown in FIG. 4, some of the multiple shutoff valve units 50 may be dedicated to one utilization unit 30.

For example, in FIG. 4, the air conditioner 100 has multiple groups of utilization units 30 each including multiple utilization units 30 (first to Nth groups). One shutoff valve unit 50 is associated with the utilization units 30 in each group.

In this case, for example, assume that one refrigerant sensor 38 of the first group of user units 30 detects a refrigerant leak. In this case, the shutoff valve 52 of the shutoff valve unit 50 corresponding to the first group of user units 30 is fully closed, and the user expansion valves 36 of all the first group of user units 30 are also fully closed.

At this time, if no refrigerant leakage is detected in the utilization units 30 of the second to Nth groups, the operation of the heat source unit 10 and the utilization units 30 of the second to Nth groups may be continued.

Second Embodiment
An air conditioner 100A of the second embodiment will be described with reference to the schematic configuration diagrams of FIGS.

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 multiple groups of utilization units 30, each of which includes multiple utilization units 30, and the utilization units 30 of each group can individually select cooling operation or heating operation, and has an intermediate unit 150 as an example of a shutoff valve unit.

The air conditioner 100A has many similarities to the air conditioner 100 of the first embodiment, so the differences will be mainly described here, and the commonalities will not be described unless otherwise necessary.

(1) Overall Overview An air conditioner 100A as an example of a refrigeration cycle device mainly includes one heat source unit 110, a plurality of utilization units 30, a plurality of intermediate units 150 that switch the flow of refrigerant between the heat source unit 10 and the utilization units 30, and communication piping that connects the heat source unit 110, the intermediate unit 150, and the utilization units 30. In the air conditioner 100A, one intermediate unit 150 is shared by the plurality of utilization units 30. The plurality of utilization units 30 that share the intermediate unit 150 are called a group of utilization units 30. In the example of FIG. 6, the air conditioner 100A has two intermediate units 150, and the utilization units 30 include utilization units 30 of group A that share one intermediate unit 150 (150A) and utilization units 30 of group B that share the other intermediate unit 150 (150B).

In the air conditioner 100A, the heat source unit 110, the intermediate unit 150, and the utilization unit 30 are connected via communication piping to form the refrigerant circuit 190.

The connecting pipes include a liquid connecting pipe 102a, an intake gas connecting pipe 102b, a high and low pressure gas connecting pipe 102c, a first connecting pipe 102d, a second connecting pipe 102e, a third connecting pipe 102f, and a connecting pipe 104b.

(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 diagram of a refrigerant circuit within the heat source unit 110 of the air conditioner 100A.

The heat source unit 110 is installed on the rooftop or machine room of the building in which the air conditioner 100 is installed. The heat source unit 110 mainly includes a first gas-side shutoff valve 119a, a second gas-side shutoff valve 119b, a liquid-side shutoff 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. These devices are connected via refrigerant piping to form a part of the refrigerant circuit 190. The heat source unit 110 also includes a heat source fan 22 and a heat source control unit 74.

The first gas-side shutoff valve 119a, the second gas-side shutoff valve 119b, and the liquid-side shutoff valve 119c are manual valves that are opened and closed when charging the refrigerant, pumping down, etc. One end of the first gas-side shutoff valve 119a is connected to the suction gas connection pipe 102b, and the other end is connected to the refrigerant piping that extends to the accumulator 20. One end of the second gas-side shutoff valve 119b is connected to the high-low pressure gas connection pipe 102c, and the other end is connected to the refrigerant piping that extends to the second flow path switching valve 14b. One end of the liquid-side shutoff valve 119c is connected to the liquid connection pipe 102a, and the other end is connected to the refrigerant piping that extends to the first heat source expansion valve 118a or the second heat source expansion valve 118b.

The accumulator 20 is the same device as the accumulator 20 in the first embodiment. The accumulator 20 is disposed between the gas-side first shutoff valve 119a and the compressor 12.

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

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 refrigerant depending on the situation (see the solid and dashed lines in FIG. 5). The refrigerant inlet of the flow path switching valve 14A is connected to the discharge pipe of the compressor 12 or a branch pipe extending from the discharge pipe. The flow path switching valve 14A is configured to block the flow of refrigerant in one refrigerant flow path, 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 depending on the operation of the air conditioner 100A will be explained together with the explanation of the refrigerant flow in the air conditioner 100A.

The heat source heat exchanger 116 has a similar configuration to the heat source heat exchanger 16 of the first embodiment, but includes a first heat exchange section 116a and a second heat exchange section 116b. One end of the first heat exchange section 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 section 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 section 116a and the second heat exchange section 116b exchanges heat with the airflow generated by the heat source fan 22.

The first heat source expansion valve 118a and the second heat source expansion valve 118b are, for example, motorized valves whose opening degree can be adjusted. One end of the first heat source expansion valve 118a is connected to a refrigerant pipe extending from the first heat exchange section 116a, and the other end is connected to a refrigerant pipe extending to the liquid side stop valve 119c. One end of the second heat source expansion valve 118b is connected to a refrigerant pipe extending from the second heat exchange section 116b, and the other end is connected to a refrigerant pipe extending to the liquid side stop valve 119c. The opening degree of the first heat source expansion valve 118a and the second heat source expansion valve 118b is adjusted according to the situation, and the refrigerant passing through the inside is reduced in pressure according to the opening degree.

The heat source fan 22 is a device similar to the heat source fan 22 in the first embodiment, and generates an air flow 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.

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

(2-2) Utilization Unit The configuration of the utilization unit 30 is similar to that of the utilization unit in the first embodiment, and therefore a description thereof will be omitted.

(2-3) Intermediate unit The communication pipe 104b, the second connection pipe 102e, the intake gas communication pipe 102b, and the pipe connecting the gas side second shutoff valve 119b and the compressor 12, or the communication pipe 104b, the third connection pipe 102f, the high and low pressure gas communication pipe 102c, and the pipe connecting the gas side first shutoff 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 multiple utilization 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 10, a second pipe 104c extending from the utilization unit 30, and a branching portion 104d that branches the first pipe into multiple second pipes 104c. The interconnecting pipe 104b is a portion of the interconnecting pipe 4 that connects the heat source unit 10 and the branching portion 104d. The second pipe 104c is a portion of the interconnecting pipe 4 that connects the utilization unit 30 and the branching portion 104d.

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

The intermediate unit 150 is placed in the same location (such as above the ceiling) as the shutoff valve unit 50 of the first embodiment. Here, to avoid duplication, the description of the installation location of the intermediate unit 150 is omitted.

As shown in FIG. 6, the intermediate units 150 are arranged in the same number as the number of groups of utilization units 30 so as to correspond to the multiple utilization units 30 (groups of utilization units 30). Note that some of the multiple intermediate units 150 may be associated with a single utilization unit 30 instead of multiple 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.

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

The expansion valves 152a, 152b are provided in the second connecting pipe 102e, the third connecting pipe 102f, and the interconnecting pipe 104b, and are mechanisms for adjusting the pressure and flow rate of the refrigerant. The expansion valves 152a, 152b are motor-operated valves (electronic expansion valves) that can adjust the opening degree. The expansion valves 152a, 152b are also used as shutoff valves in the event of refrigerant leakage, and are valves that have a small leakage amount when closed. For example, the expansion valves 152a, 152b are valves that have a leakage amount of 300 cm ³ /min (air, ΔP=1.0 MPa) or less when closed.

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

The valve control unit 76 is structurally similar to 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.

(2-4) Connection Pipes The liquid connection pipe 102a has one end connected to the liquid side shutoff valve 119c, and the other end connected to a plurality of first connection pipes 102d. The first connection pipe 102d has one end connected to the liquid connection pipe 102a, and the other end branches off and is connected to a plurality of utilization units 30 belonging to one group. The intake gas connection pipe 102b has one end connected to the gas side first shutoff valve 119a, and the other end connected to the second connection pipe 102e extending from each intermediate unit 150. The high and low pressure gas connection pipe 102c has one end connected to the gas side second shutoff valve 119b, and the other end connected to the third connection pipe 102f extending from each intermediate unit 150. Each second connection pipe 102e has one end connected to the intake gas connection pipe 102b, and the other end connected to a pipe in which the expansion valve 152a of the intermediate unit 150 is arranged. One end of each of the third connection pipes 102f is connected to the high/low pressure gas connection pipe 102c, and the other end is connected to a pipe in which the expansion valve 152b of the intermediate unit 150 is disposed. Each connection pipe 104b is connected to a pipe in which the pipe in which the expansion valve 152a is disposed and the pipe in which the expansion valve 152b is disposed of of the intermediate unit 150 join together. One end of each connection pipe 104b branches at a branching portion 104d, flows through a plurality of second pipes 104c, and is connected to a plurality of utilization units 30.

(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 and arithmetic devices of the usage control unit 72, the heat source control unit 74, and the valve control unit 76 to execute programs stored in their respective storage devices.

Figure 7 is a control block diagram of the air conditioner 100A in this embodiment.

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 utilization units 30, the compressor 12, flow path switching valve 14A, heat source expansion valves 118a, 118b, and heat source fan 22 of the heat source unit 10, and the expansion valves 152a, 152b of each of the intermediate units 150. The control unit 70 is also 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 operation of various devices of the air conditioner 100A based on control signals received by the utilization units 30 from an operation remote control (not shown) and measurement signals of various sensors, etc.

(3) Refrigerant Flow During Operation of the Air Conditioner The flow of refrigerant during operation of the air conditioner 100A will be described for each situation, taking as an example a case in which the utilization unit 30A of group A and the utilization unit 30B of group B in FIG. 6 are in operation.

(3-1) When both the utilization units 30A and 30B are in cooling operation When both the utilization units 30A and the utilization units 30B are in cooling operation, in the intermediate unit 150A corresponding to the utilization units 30A and the intermediate unit 150B corresponding to the utilization units 30B, the expansion valve 152a is fully opened and the expansion valve 152b is at the minimum opening degree. In addition, the opening degree of each utilization expansion valve 36 of the utilization units 30A and the utilization units 30B is appropriately adjusted, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are fully opened.

The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 starts operating, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The compressed high-pressure gas refrigerant passes through the discharge pipe, the first flow path switching valve 14a, the third flow path switching valve 14c, etc., and flows into the heat source heat exchanger 116 and condenses. The refrigerant that passes through the heat source heat exchanger 116 passes through the liquid side stop valve 119c and flows into the liquid communication pipe 102a. The refrigerant that passes through the liquid communication pipe 102a reaches the first connection pipe 102d and flows into the multiple utilization units 30A and the multiple utilization units 30B.

The refrigerant that reaches the multiple utilization units 30A or multiple utilization units 30B flows into the utilization expansion valve 36 and is depressurized. The depressurized refrigerant flows into each utilization heat exchanger 32 and evaporates. The refrigerant that passes through each utilization heat exchanger 32 flows through the connection pipe 104b into the pipe in which the expansion valve 152a of the intermediate units 150A and 150B is located, and reaches the second connection pipe 102e. The refrigerant that reaches 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.

(3-2) When both the utilization units 30A and 30B are performing heating operation When both the utilization units 30A and 30B are performing heating operation, in the intermediate units 150A and 150B, the expansion valves 152a are set to the minimum opening degree, and the expansion valves 152b are set to the full opening degree. In addition, the utilization expansion valves 36 of the utilization units 30A and 30B are set to the full opening degree, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are appropriately adjusted in opening degree.

The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 starts operating, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The compressed high-pressure gas refrigerant flows into the high-low pressure gas connection pipe 102c through the discharge pipe and the second flow path switching valve 14b, etc. The refrigerant that has passed through the high-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 which the expansion valve 152b of the intermediate unit 150A or 150B is located, and then passes through the connection pipe 104b to reach the multiple user units 30A or the multiple user units 30b.

The refrigerant that reaches the multiple utilization units 30A or the multiple utilization units 30B flows into each utilization heat exchanger 32 and condenses. The refrigerant that passes through each utilization heat exchanger 32 flows into the first connection pipe 102d. The refrigerant that reaches the first connection pipe 102d reaches the heat source unit 110 via the liquid connection pipe 102a.

The refrigerant that reaches the heat source unit 110 passes through the first heat source expansion valve 118a or the second heat source expansion valve 118b and is depressurized according to the opening degree. The depressurized refrigerant flows into the heat source heat exchanger 116 and evaporates. The refrigerant that passes through the heat source heat exchanger 116 passes through the first flow path switching valve 14a or the third flow path switching valve 14c and is sucked back into the compressor 12.

(3-3) When either one of the utilization units 30A and 30B performs cooling operation and the other performs heating operation For example, when the multiple utilization units 30A perform cooling operation and the multiple utilization units 30B perform heating operation, in the intermediate unit 150A, the expansion valve 152a is fully opened and the expansion valve 152b is at a minimum opening. Also, the utilization expansion valves 36 of the multiple utilization units 30A are appropriately adjusted in opening. In the intermediate unit 150B, the expansion valve 152a is at a minimum opening and the expansion valve 152b is fully opened. Also, the utilization expansion valves 36 of the multiple utilization units 30B are fully opened. And the first heat source expansion valve 118a and the second heat source expansion valve 118b are appropriately adjusted in opening.

The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 is operating, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The high-pressure gas refrigerant compressed by the compressor 12 flows into the high- and low-pressure gas communication pipe 102c via the discharge pipe and the second flow path switching valve 14b, etc. The refrigerant that has passed through the high- and low-pressure gas communication pipe 102c reaches the third connection pipe 102f. The refrigerant that has passed through the third connection pipe 102f flows into the intermediate unit 150B, flows through the pipe in which the expansion valve 152b is located, and flows into the communication pipe 104b.

The refrigerant that passes through the connection pipe 104b reaches the multiple utilization units 30B, flows into the utilization heat exchanger 32, and condenses. The condensed refrigerant passes through the first connection pipe 102d, flows into the first connection pipe 102d that is connected to the multiple utilization units 30A, and reaches the multiple utilization units 30A.

The refrigerant that reaches the multiple 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 connection pipe 104b, reaches the intermediate unit 150A, flows into the pipe where the expansion valve 152a is located, and reaches the second connection pipe 102e.

The refrigerant that reaches the second connection pipe 102e flows through the intake gas connection pipe 102b into the heat source unit 110 and is sucked back into the compressor 12.

(3-4) Refrigerant Leakage Prevention Function When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the control unit 70 fully closes the expansion valves 152a, 152b of the intermediate unit 150 associated with the utilization unit 30 in which the refrigerant sensor 38 has detected a refrigerant leak (hereinafter referred to as the leaking utilization unit). When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the control unit 70 fully closes the utilization expansion valve 36 of the leaking utilization unit and the utilization expansion valves 36 of the 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 shutoff valve 52 of the shutoff valve unit 50 associated with the leaking utilization unit together with the leaking utilization unit by the gas piping GP.

For example, in the example of FIG. 6, when a refrigerant leak is detected in one of the utilization units 30A of group A, since the two utilization units 30A belonging to group A are connected to the heat source unit 10 via the expansion valves 152a, 152b of one intermediate unit 150A, the control unit 70 fully closes the utilization expansion valves 36 of the two utilization units 30A. This blocks the inflow of refrigerant from the heat source unit 110 through the connecting piping to the leaking utilization unit and the utilization units of the leaking group (to the utilization unit 30A of group A).

In the second embodiment, the utilization expansion valve 36 of the utilization unit 30 is also closed according to the signal flow shown in FIG. 8.

First, when the refrigerant sensor 38 of the leaking utilization unit (referred to as utilization unit A in FIG. 8) belonging to group A detects a refrigerant leak, it transmits a signal notifying the refrigerant leak to the utilization control unit 72 (an example of a controller in the claims) of the utilization unit A in which the refrigerant sensor is installed.

The usage control unit 72 of the usage unit A receives this and transmits a command to close the expansion valves 152a and 152b to the valve control unit 76 of the intermediate unit 150A. The usage control unit 72 of the usage unit A also notifies the usage control units 72 of the usage units other than the usage unit A that a refrigerant leak has occurred in the usage unit A (in FIG. 8, usage units B and C) belonging to group A. In other words, the usage control unit 72 of the usage unit A transmits a command to close the usage expansion valve 36 to the usage control units 72 of the usage units B and C. Furthermore, the usage control unit 72 of the usage unit A fully closes the usage expansion valve 36 of the usage unit A. The usage control unit 72 of the usage unit A also stops the operation of the usage unit A (stops the operation of the usage fan 34).

The utilization control units 72 of utilization units B and C, upon receiving a refrigerant leakage notification from utilization unit A (in other words, a command to close the utilization expansion valve 36), fully close the utilization expansion valves 36 of utilization units B and C, respectively. In addition, the utilization control units 72 of utilization units B and C, upon receiving a refrigerant leakage notification from utilization unit A (in other words, a command to close the utilization expansion valve 36), stop the operation of the utilization fans 34 of utilization units B and C, respectively.

The usage control unit 72 of usage unit A also notifies the heat source control unit 74 of the heat source unit 10 that a refrigerant leak has occurred in usage unit A.

Here, even if refrigerant is leaking from utilization unit A, utilization unit 30B in group B can still operate. However, if all utilization units 30A in group A stop, the amount of circulating refrigerant, etc. will change, so the heat source control unit 74 of heat source unit 10 adjusts the rotation speed of compressor 12 and the opening degree of heat source expansion valves 118a, 118b, etc.

If a refrigerant leak is detected in any of the utilization units 30, the control unit 70 may stop the operation of the compressor 12 and may also stop the cooling/heating operation in the utilization units 30 other than the one in which the refrigerant leak is detected.

(4) Features (4-1)
The air conditioner 100A as an example of a refrigeration cycle device includes a heat source unit 110, a plurality of utilization units 30, a gas pipe GP, and expansion valves 152a and 152b as an example of a first shutoff valve. The heat source unit 110 has a compressor 12 and a heat source heat exchanger 118. Each of the plurality of utilization units 30 has a utilization heat exchanger 32. The gas pipe GP connects the compressor 12 of the heat source unit 110 and the utilization heat exchangers 32 of the plurality of utilization units 30. The gas pipe GP includes a first pipe (a connection pipe 104b, a second connection pipe 102e, and a third connection pipe 102f) extending from the heat source unit 110, a second pipe 104c extending from the utilization unit 30, and a branching portion 104d that branches the first pipe into a plurality of second pipes 104c. The expansion valves 152a and 152b are disposed in the gas piping GP closer to the heat source unit 110 than the branching portion 104d. Each utilization unit 30 has an adjustable utilization expansion valve 36 provided in a liquid piping connecting the utilization heat exchanger 32 of the utilization unit 30 and the heat source heat exchanger 118 of the heat source unit 110.

In the air conditioner 100A, the gas piping GP is provided with expansion valves 152a and 152b as first shutoff valves common to multiple utilization units 30, and each utilization unit 30 is provided with an adjustable opening utilization expansion valve 36 (a shutoff valve that is also used as an expansion valve). Therefore, the air conditioner 100A can respond to refrigerant leakage from the utilization unit 30 while reducing the number of parts.

(4-2)
In the air conditioner 100A, the expansion valves 152a and 152b are flow rate regulating valves whose opening degrees are adjustable.

In this air conditioner 100A, the expansion valves 152a and 152b serving as the first shutoff valves can be used not only as shutoff valves but also for flow rate adjustment purposes, which allows for a reduction in the number of parts.

(4-3)
In the air conditioner 100A, each utilization unit 30 has a refrigerant sensor 38. When the refrigerant sensor 38 of one utilization unit 30 detects a refrigerant leak, the expansion valves 152a, 152b (of the intermediate unit 150) corresponding to the leaking utilization unit and the utilization expansion valves 36 of the multiple utilization units 30 connected to the heat source unit 110 via the expansion valves 152a, 152b by the gas piping GP are closed.

This air conditioner 100A reduces the number of parts while preventing the occurrence of a situation in which the concentration of leaking refrigerant becomes high in the space in which the utilization unit 30 is installed.

(4-4)
In the air conditioner 100A, the utilization unit 30 has a utilization control unit 72 as an example of a controller. When the refrigerant sensor of each utilization unit 30 detects a refrigerant leak, it sends a signal to the utilization control unit 72 of the utilization unit 30 in which the refrigerant sensor is provided. The utilization control unit 72 of the utilization unit 30 in which the refrigerant sensor 38 that detected the refrigerant leak is provided sends a command to close the utilization expansion valve 36 to the utilization control units 72 of the other utilization units 30 that are connected to the heat source unit 110 via the expansion valves 152a, 152b by the gas piping GP together with the utilization unit 30 in which the leak was detected.

In the air conditioner 100A, the utilization unit 30 receives a command to close the utilization expansion valve 36 from a utilization unit 30 located nearby without going through the heat source unit 110, so that in the event of a refrigerant leak, the flow of refrigerant from the heat source unit 110 to the utilization unit 30 can be blocked early.

(4-5)
In the air conditioner 100A, when the utilization unit 30 receives a command to close the utilization expansion valve 36, it stops operating.

In this air conditioner 100A, the operation of the utilization unit 30 (particularly the utilization fan 34) of the group to which the leaking utilization unit belongs (which shares the same shutoff valve unit 50 as the leaking utilization unit) is stopped, which makes it easier to prevent the refrigerant flowing out of the utilization unit 30 from diffusing into the space in which the utilization unit 30 is installed.

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

＜Other＞
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.

4a First pipe 4b Second pipe 4c Branching section 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 shutoff valve)
38 Refrigerant sensor 52 Shutoff valve (first shutoff valve)
72 Usage control unit (controller)
100, 100A Air conditioner (refrigeration cycle device)
102e Second connection pipe (first pipe)
102f third connection pipe (first pipe)
104b Interconnecting pipe (first pipe)
104c: Second pipe 104d: Branching portion 152a, 152b: Expansion valve (first shutoff valve)
GP Gas piping LP Liquid piping

Patent No. 6927315

Claims (3)

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 utilization units (30) each having a utilization heat exchanger (32) , a utilization controller (72), and a refrigerant sensor (38) ;
a gas piping (GP) including a first piping (4a, 104b, 102e, 102f) extending from the heat source unit, a second piping (4b, 104c) extending from the utilization unit, and a branching section (4c, 104d) that branches the first piping into a plurality of the second pipings, and connecting the compressor of the heat source unit and the utilization heat exchangers of the plurality of utilization units;
a first shutoff valve (52, 152a, 152b) disposed in the gas piping closer to the heat source unit than the branching portion;
Equipped with
Each of the utilization units has a second shutoff valve (36) whose opening degree is adjustable and which is provided in a liquid pipe (LP) connecting the utilization heat exchanger of the utilization unit and the heat source heat exchanger of the heat source unit ;
When the refrigerant sensor of one of the utilization units detects a refrigerant leak, the first shutoff valve and the second shutoff valves of the utilization units connected to the heat source unit via the first shutoff valve by the gas piping are closed,
When the refrigerant sensor of each of the utilization units detects a refrigerant leak, the refrigerant sensor transmits a signal to the utilization controller of the utilization unit in which the refrigerant sensor is provided;
The usage controller of the usage unit in which the refrigerant sensor that has detected the refrigerant leakage is provided transmits a command to close the second shutoff valve to the usage controllers of the other usage units that are connected to the heat source unit via the first shutoff valve by the gas piping together with the usage unit in which the leakage has been detected, without going through the heat source controller.
Refrigeration cycle device (100, 100A). The first shutoff valve (152a, 152b) is a flow rate adjustment valve whose opening degree is adjustable.
The refrigeration cycle apparatus (100A) according to claim 1. When the utilization unit receives a command to close the second shutoff valve, the utilization unit stops operating.
The refrigeration cycle device according to claim 1 or 2 .

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