Air conditioner

Abstract

To provide an air conditioner that allows a refrigerant to be quickly collected from a utilization unit from which the refrigerant leaks when the refrigerant leaks.SOLUTION: An air conditioner 100 comprises a heat source unit 10, a utilization unit 30, communication pipes 2 and 4, a shut-off valve 52, and a service port 60. The utilization unit is arranged in an air conditioning space. The communication pipes 2 and 4 connect the heat source unit and the utilization unit. The shut-off valve is arranged outside the air conditioning space, and provided in the communication pipe 4. The service port 60 is provided between the shut-off valve and the utilization unit in the communication pipe 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an air conditioner. [Background technology]

[0002] BACKGROUND ART Conventionally, as in Patent Document 1 (JP 2023-50282 A), a refrigeration cycle apparatus is known in which a service port is provided in a heat source unit in order to recover a refrigerant from the refrigeration cycle apparatus. Summary of the Invention [Problem to be solved by the invention]

[0003] In such a refrigeration cycle apparatus, when a refrigerant leak is detected in a utilization unit, it may take a long time to complete the recovery of the refrigerant from the utilization unit from which the refrigerant is leaking. [Means for solving the problem]

[0004] An air conditioner according to a first aspect includes a heat source unit, a utilization unit, a communication pipe, a shutoff valve, and a service port. The utilization unit is disposed in the air-conditioned space. The communication pipe connects the heat source unit and the utilization unit. The shutoff valve is disposed outside the air-conditioned space and is provided in the communication pipe. The service port is provided in the communication pipe between the shutoff valve and the utilization unit.

[0005] In the air conditioner of the first aspect, the service port is provided closer to the utilization unit than the shutoff valve that shuts off the flow of refrigerant to the utilization unit. Therefore, in the air conditioner of the first aspect, in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit from which the refrigerant is leaking.

[0006] An air conditioner according to a second aspect is the air conditioner according to the first aspect, further comprising a shutoff valve unit having a shutoff valve and a casing that houses the shutoff valve. The service port is provided in the shutoff valve unit. The service port is disposed outside the casing.

[0007] In the air conditioner of the second aspect, because the service port is provided on the shutoff valve unit, when the shutoff valve unit is attached to the connecting pipe, the service port can also be attached to the connecting pipe, which makes installation more efficient. Also, in this air conditioner, because the service port is located outside the casing, the refrigerant recovery work is highly efficient.

[0008] An air conditioner according to a third aspect is the air conditioner according to the second aspect, wherein the service port is disposed on a side of the casing.

[0009] The service port can be located either above or below the casing. However, if the service port is located below the casing, there is a risk of oil collecting in the port area. Furthermore, if the service port is located above the casing and the casing housing the shutoff valve is located above the ceiling, there is a risk that refrigerant recovery work will be difficult.

[0010] In contrast to this, in the air conditioner of the third aspect, the service port is provided on the side of the casing, so that the problem of oil accumulation can be suppressed and good workability in refrigerant recovery can be obtained.

[0011] An air conditioner according to a fourth aspect is the air conditioner according to the first aspect, further comprising a shutoff valve unit having a shutoff valve and a casing that houses the shutoff valve. The shutoff valve unit is provided with a service port. The service port is disposed within the casing.

[0012] In the air conditioner of the fourth aspect, the service port is provided inside the casing, so that condensation around the service port can be suppressed.

[0013] An air conditioner according to a fifth aspect is the air conditioner according to any one of the first to fourth aspects, wherein the shutoff valve is a flow rate adjustment valve whose opening is adjustable.

[0014] In the air conditioner of the fifth aspect, the shutoff valve also functions as a flow rate adjusting valve, so that the number of parts can be reduced.

[0015] An air conditioner according to a sixth aspect is the air conditioner according to any one of the first aspect to the fifth aspect, wherein the shutoff valve is provided in a gas communication pipe that connects the heat source unit and the utilization units.

[0016] In the air conditioner of the sixth aspect, the refrigerant remaining between the utilization expansion valve and the shutoff valve of the utilization unit that is fully closed when a refrigerant leak is detected can be recovered from the service port.

[0017] An air conditioner according to a seventh aspect is the air conditioner according to any one of the first to sixth aspects, in which the length of the connecting pipe between the shutoff valve and the utilization unit is 2 m or less.

[0018] In the air conditioner of the seventh aspect, because the shutoff valve is provided near the utilization unit, in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit from which the refrigerant is leaking.

[0019] An eighth aspect of the present invention is an air conditioner according to any one of the first to seventh aspects, wherein the utilization unit is a ceiling-embedded type. The service port is provided in the attic space, near an inspection hatch for the utilization unit provided in the ceiling.

[0020] In the air conditioner of the eighth aspect, a shutoff valve is provided near the inspection hatch for the utilization unit, so that in the event of a refrigerant leak from the utilization unit, the refrigerant can be quickly recovered from the utilization unit from which the refrigerant is leaking.

[0021] An air conditioner according to a ninth aspect is the air conditioner according to any one of the first to sixth aspects, wherein the length of the connecting pipe between the shutoff valve and the utilization unit is 40 m or less.

[0022] In the air conditioner of the ninth aspect, the length of the connecting pipe between the shutoff valve and the utilization unit is 40 m or less, so even if refrigerant leaks from a refrigerant leakage point in the utilization unit before refrigerant recovery is complete, the refrigerant concentration in the air-conditioned space is unlikely to become high.

[0023] An air conditioner according to a tenth aspect is the air conditioner according to any one of the first to ninth aspects, wherein the service port is installed in a position accessible from outside the air-conditioned space.

[0024] If a refrigerant leaks from a utilization unit, the refrigerant may flow into the air-conditioned space that is the target of air conditioning for that utilization unit. In the air conditioner of the tenth aspect, the service port is accessible from outside the air-conditioned space, so workers can recover the refrigerant without entering the air-conditioned space where the refrigerant may be present, resulting in a high level of safety.

[0025] An air conditioner according to an eleventh aspect is the air conditioner according to any one of the first to tenth aspects, comprising a plurality of utilization units, each of which is provided with a dedicated shutoff valve and service port.

[0026] In the air conditioner of the eleventh aspect, if a refrigerant leaks from one of a plurality of utilization units, refrigerant can be recovered from the utilization unit from which the refrigerant is leaking, while the other utilization units can continue to operate. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic configuration diagram of an air conditioner according to a first embodiment. [Figure 2] FIG. 2 is a control block diagram of the air conditioner of FIG. [Figure 3] FIG. 2 is a schematic perspective view of a shutoff valve unit of the air conditioner of FIG. 1. [Figure 4] FIG. 2 is a diagram showing an example of the arrangement of a shutoff valve unit of the air conditioner of FIG. [Figure 5] 1. FIG. 4 is a diagram showing another example of the arrangement of the shutoff valve unit of the air conditioner of FIG. [Figure 6] FIG. 10 is a diagram of a refrigerant circuit in a heat source unit of an air conditioner according to a second embodiment. [Figure 7] FIG. 10 is a refrigerant circuit diagram of the air conditioner according to the second embodiment, other than the heat source unit. [Figure 8] FIG. 10 is a control block diagram of an air conditioner according to a second embodiment. [Figure 9] FIG. 10 is a schematic perspective view of a shutoff valve unit of an air conditioner according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment of an air conditioner will be described with reference to the drawings.

[0029] First Embodiment (1) Overall structure An air conditioner 100 of the first embodiment will be described with reference to the schematic configuration diagram of FIG.

[0030] 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, a shutoff valve unit 50 and a service port 60 provided for each of the multiple utilization units 30, and a controller 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. Also, unlike this embodiment, the air conditioner 100 may have only one utilization unit 30 and be a device that conditions a single air-conditioned space.

[0031] As shown in FIG. 1 , the heat source unit 10 and the utilization units 30 are connected by communication pipes 2 and 4. By connecting the heat source unit 10 and the utilization units 30 by the communication pipes 2 and 4, a refrigerant circuit 90 is formed, which includes a compressor 12, a heat source heat exchanger 16, a heat source expansion valve 18, a utilization expansion valve 36, and a utilization heat exchanger 32, which will be described later. As shown in FIG. 1 , a shutoff valve unit 50 is provided in the communication pipe 4. The communication pipe 4 is a gas communication pipe through which refrigerant flows from the utilization units 30 to the heat source unit 10 during cooling operation, and from the heat source unit 10 to the utilization units 30 during heating operation. A service port 60 for recovering refrigerant is provided in the communication pipe 4 between the shutoff valve 52 of the shutoff valve unit 50 and the utilization units 30. A controller 70 controls the operation of each part of the air conditioner 100.

[0032] (2) Detailed configuration (2-1) Usage unit The utilization unit 30 is installed in the air-conditioned space to be air-conditioned. The utilization unit 30 may be, for example, a ceiling-embedded type, a ceiling-suspended type, a wall-mounted type, or a floor-standing type unit. In this embodiment, the following description will be given taking as an example a case where the utilization unit 30 is a ceiling-embedded type.

[0033] The 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.

[0034] In the utilization heat exchanger 32, heat exchange occurs 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.

[0035] 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).

[0036] 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 electrically operated valve (electronic expansion valve) that can adjust the opening. The utilization expansion valve 36 is also used as a shutoff valve in the event of a refrigerant leak, 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 when closed. 3 / min (air, ΔP = 1.0 MPa) or less.

[0037] The refrigerant sensor 38 is a sensor that detects refrigerant leakage and is provided near the utilization heat exchanger 32, for example.

[0038] 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 or GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs predetermined arithmetic processing in accordance with the program, thereby working together with a heat source control unit 74 of the heat source unit 10 and a valve control unit 76 of the shut-off valve unit 50 to control the operation of various devices in the air conditioner 100 as the controller 70. The functions of the controller 70 will be described later.

[0039] (2-2) Heat source unit The heat source unit 10 is installed on the roof 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 shut-off valve 24, a gas shut-off 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.

[0040] Suction pipe 28a connects the flow path switching valve 14 and the suction side of the compressor 12. An accumulator 20 is provided on suction pipe 28a. Discharge pipe 28b connects the discharge side of the compressor 12 and the flow path switching valve 14. Gas refrigerant pipe 28c connects the flow path switching valve 14 and the gas side end of the heat source heat exchanger 16. Liquid refrigerant pipe 28d connects the liquid side end of the heat source heat exchanger 16 and the connection pipe 2. A heat source expansion valve 18 is provided on liquid refrigerant pipe 28d. A liquid stop valve 24 is provided at the connection between the liquid refrigerant pipe 28d and the connection pipe 2. Gas refrigerant pipe 28e connects the flow path switching valve 14 and the connection pipe 4. A gas stop valve 26 is provided at the connection between the gas refrigerant pipe 28e and the connection pipe 4. The liquid stop valve 24 and the gas stop valve 26 are valves that are opened and closed manually.

[0041] The compressor 12 draws in low-pressure refrigerant in the refrigeration cycle through a suction pipe 28a, compresses the refrigerant using a compression mechanism (not shown), and discharges the compressed high-pressure refrigerant in the refrigeration cycle to a discharge pipe 28b. The compressor 12 is, for example, a rotary or scroll type positive displacement 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.

[0042] The flow path switching valve 14 is a mechanism that switches the refrigerant flow path between a first state and a second state. In the first state, the flow path switching valve 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.

[0043] 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.

[0044] 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 then 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.

[0045] 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 heat exchanger having a plurality of heat transfer fins and a plurality of heat transfer tubes.

[0046] 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 degree can be adjusted.

[0047] The accumulator 20 is provided in the suction pipe 28a and is a container having a gas-liquid separation function that separates the refrigerant that flows into the accumulator 20 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.

[0048] 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).

[0049] 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 or GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs predetermined arithmetic processing 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 in the air conditioner 100 as the controller 70. The functions of the controller 70 will be described later.

[0050] (2-3)Shut-off valve unit The shutoff valve unit 50 is disposed in the connection pipe 4 (gas connection pipe). One shutoff valve unit 50 is provided corresponding to each utilization unit 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, for example.

[0051] The shutoff valve unit 50 is placed outside the air-conditioned space. For example, the shutoff valve unit 50 is placed in the space above the ceiling of the air-conditioned space (see FIG. 4) or in the space under the floor of the air-conditioned space. The shutoff valve unit 50 is also placed in the space above the ceiling of a corridor adjacent to the air-conditioned space (see FIG. 5). The installation location of the shutoff valve unit 50 is not limited to the locations shown as examples, and it may be placed in other locations outside the air-conditioned space.

[0052] The shutoff valve unit 50 mainly includes a shutoff valve 52 , a casing 54 , and a valve control section 76 .

[0053] The shutoff valve 52 is a valve that has a small leakage amount when closed. For example, the shutoff valve 52 has a leakage amount of 300 cm 3 / min (air, ΔP=1.0 MPa) or less. However, the type of valve is not limited to a solenoid valve, and may be an electrically operated valve or the like that is capable of adjusting the opening degree.

[0054] It is preferable that the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 (the total length of the pipe on the utilization unit 30 side of the shutoff valve 52 in the shutoff valve unit 50 and the communication pipe 4 connecting the shutoff valve unit 50 and the utilization unit 30) be 40 m or less. With this configuration, even if refrigerant leaks from a refrigerant leakage point in the utilization unit before refrigerant recovery from the service port 60 provided between the shutoff valve 52 and the utilization unit 30 is completed, the length of the pipe included in the refrigerant recovery portion is relatively short and the amount of refrigerant in the pipe is relatively small, so the refrigerant concentration in the air-conditioned space is unlikely to become high.

[0055] Furthermore, the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 is preferably 2 m or less. With this configuration, it is possible to quickly recover refrigerant from the utilization unit 30 in which refrigerant is leaking, by using the service port 60 provided between the shutoff valve 52 and the utilization unit 30.

[0056] The casing 54 is a housing that houses the shutoff valve 52. A moisture-proof material is disposed inside the casing 54, which prevents condensation around the shutoff valve 52.

[0057] The valve control unit 76 has a control and arithmetic device and a storage device. The control and arithmetic device is a processor such as a CPU or GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control and arithmetic device reads out a program stored in the storage device and performs predetermined arithmetic processing 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 in the air conditioner 100 as the controller 70. The functions of the controller 70 will be described later.

[0058] (2-4) Service port The service port 60 is a component for recovering the refrigerant filled in the air conditioner 100. When recovering the refrigerant, a refrigerant recovery container is connected to the service port 60 via connecting components and a hose, and the refrigerant is recovered into the refrigerant recovery container.

[0059] The service port 60 is provided in the connecting pipe 4 between the shutoff valve 52 of the shutoff valve unit 50 and the utilization unit 30. The service port 60 may be provided in the connecting pipe 4 independently of the shutoff valve unit 50.

[0060] However, it is preferable that the service port 60 be provided in the shutoff valve unit 50 (in the piping that constitutes part of the shutoff valve unit 50 and that is located closer to the utilization unit 30 than the shutoff valve 52). If the service port 60 is provided independently of the shutoff valve unit 50, work is required to attach the service port 60 and the shutoff valve unit 50 to the connecting piping 4, but if the service port 60 is incorporated into the shutoff valve unit 50 in advance, on-site work can be reduced.

[0061] Furthermore, if the service port 60 is positioned outside the casing 54 of the shutoff valve unit 50 as shown by the solid line in Figure 3, the worker can start the refrigerant recovery work without removing the cover or the like that covers the shutoff valve 52 of the shutoff valve unit 50, which improves workability.

[0062] In this way, when the service port 60 is disposed outside the casing 54, it is particularly preferable that the service port 60 be disposed on the side of the casing 54. In other words, it is particularly preferable that the service port 60 be provided in a position that is accessible to an operator from the side of the casing 54.

[0063] For example, the service port 60 may be located above the casing 54, in a position that is accessible to an operator from above the casing 54. However, in this case, if the shutoff valve unit 50 is installed in the ceiling space, it may be difficult for an operator to access. Also, the service port 60 may be located below the casing 54, but in this case, if the shutoff valve unit 50 is installed in the ceiling space, there is a risk of oil accumulating in the area of ​​the service port 60.

[0064] In contrast, by arranging the service port 60 on the side of the casing 54, the problem of oil accumulation in the service port 60 can be suppressed, and good operability can be achieved in recovering the refrigerant.

[0065] Furthermore, if the service port 60 is located inside the casing 54 of the shut-off valve unit 50 as shown by the dashed line in Figure 3, it will be necessary to remove the cover that covers the shut-off valve 52, etc., but since the service port 60 is not exposed to the surrounding environment, the occurrence of condensation at the service port 60 can be suppressed.

[0066] If the utilization unit 30 is a ceiling-embedded type, the service port 60 (or the shutoff valve unit 50, if the service port 60 is provided in the shutoff valve unit 50) is provided in the ceiling space near the inspection hatch OP of the utilization unit 30, which is provided in the ceiling. Near the inspection hatch OP of the utilization unit 30 means that the service port 60 is within reach (e.g., 50 cm) from the inspection hatch OP. If the service port 60 is provided separately from the shutoff valve unit 50, it is preferable that at least the service port 60 be provided in the ceiling space near the inspection hatch OP of the utilization unit 30, which is provided in the ceiling. With this configuration, in the event of a refrigerant leak from the utilization unit 30, the refrigerant can be quickly recovered from the leaking utilization unit 30.

[0067] Furthermore, from the viewpoint of worker safety, it is preferable that the service port 60 be located in a position accessible from outside the air-conditioned space. For example, the service port 60 (particularly when the service port 60 is provided in the shutoff valve unit 50, the shutoff valve unit 50) is provided in the ceiling space above the corridor adjacent to the air-conditioned space, near an inspection hatch OP provided in the ceiling. Near the inspection hatch OP means a distance (e.g., 50 cm) within reach of the service port 60 from the inspection hatch OP. If refrigerant leaks from the utilization unit 30, the refrigerant may flow into the air-conditioned space. In response to this, by locating the service port 60 in a position accessible from outside the air-conditioned space, workers can recover the refrigerant without entering the air-conditioned space where the refrigerant may be present.

[0068] (2-5) Controller The controller 70 is composed of a usage control unit 72, a heat source control unit 74, and a valve control unit 76. The controller 70 controls the overall operation of the 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.

[0069] FIG. 2 is a control block diagram of the air conditioner 100 in this embodiment.

[0070] 2, the controller 70 is electrically connected to the utilization expansion valves 36, utilization fans 34, and refrigerant sensors 38 of each of the multiple 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 multiple shutoff valve units 50. The controller 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 controller 70 controls the operation of the various devices of the air conditioner 100 based on control signals received by the utilization units 30 from an operation remote control (not shown), measurement signals from the various sensors, etc.

[0071] The controller 70 mainly performs cooling and heating operations and also has a function to prevent refrigerant leakage.

[0072] (2-5-1) Cooling operation When the controller 70 receives an instruction to perform cooling operation from, for example, an operation remote control via the utilization unit 30, it switches the flow path switching valve 14 to the first state and starts operation of the compressor 12. Furthermore, based on the measurement results of sensors that measure the temperature and pressure of the refrigerant 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.

[0073] The flow of refrigerant in the refrigerant circuit 90 will be described. When the compressor 12 starts operating, low-pressure gas refrigerant in the refrigeration cycle (hereinafter simply referred to as low-pressure) is drawn into the compressor 12 and compressed by the compression mechanism of the compressor 12 to become high-pressure gas refrigerant in the refrigeration cycle (hereinafter simply referred to as high-pressure). The high-pressure gas refrigerant is sent to the heat-source heat exchanger 16 via the flow path switching valve 14, where it condenses through heat exchange with the air around the heat source unit 10 supplied by the heat-source fan 22, becoming 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 in the utilization expansion valve 36 to near the suction pressure of the compressor 12, becoming a two-phase gas-liquid refrigerant, and being sent to the utilization heat exchanger 32. In the utilization heat exchanger 32, the two-phase gas-liquid refrigerant exchanges heat with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34, evaporating to become a low-pressure gas refrigerant. The low-pressure gas refrigerant is sent to the heat source unit 10 via the communication pipe 4, and flows into the accumulator 20 via the flow path switching valve 14. The low-pressure gas refrigerant that has flowed into the accumulator 20 is again sucked 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 into the air-conditioned space.

[0074] (2-5-2) Heating operation When the controller 70 receives an instruction to perform heating operation, for example, from an operation remote control via the utilization unit 30, it switches the flow path switching valve 14 to the second state and starts operation of the compressor 12. Furthermore, 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.

[0075] The flow of refrigerant in the refrigerant circuit 90 will be described. When the compressor 12 is started, low-pressure gas refrigerant is drawn into the compressor 12 and compressed by the compressor 12 to become high-pressure gas refrigerant. The high-pressure gas refrigerant is sent to the utilization heat exchanger 32 via the flow path switching valve 14, where it exchanges heat with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34, condensing and becoming high-pressure liquid refrigerant. The temperature of the air supplied to the utilization heat exchanger 32 is increased by heat exchange with the refrigerant flowing through the utilization heat exchanger 32, and the heated air is blown into the air-conditioned space. The high-pressure liquid refrigerant that has passed through the utilization heat exchanger 32 is decompressed in the utilization 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, becoming a two-phase gas-liquid refrigerant and flowing into the heat-source heat exchanger 16. The low-pressure gas-liquid two-phase refrigerant that has flowed into the heat source heat exchanger 16 exchanges heat with the air around the heat source unit 10 that is supplied by the heat source fan 22, and evaporates, becoming 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 has flowed into the accumulator 20 is again sucked into the compressor 12.

[0076] (2-5-3) Refrigerant leakage prevention function When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the controller 70 fully closes the utilization expansion valve 36 of the utilization unit 30 in which the refrigerant leak has been detected and the shut-off valve 52 of the shut-off valve unit 50 corresponding to the utilization unit 30 in which the refrigerant leak has been detected, thereby blocking the inflow of refrigerant to the utilization unit 30 through the connecting pipes 2, 4.

[0077] Even if a refrigerant leak is detected in any of the utilization units 30, the controller 70 does not stop the operation of the compressor 12, and continues the cooling operation / heating operation in the utilization units 30 other than the one in which the refrigerant leak is detected. However, when a refrigerant leak is detected in any of the utilization units 30, the controller 70 may stop the operation of the compressor 12 and also stop the cooling operation / heating operation in the utilization units 30 other than the one in which the refrigerant leak is detected.

[0078] If the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, a notification is sent, for example, to the operation remote controller, indicating which utilization unit 30 the refrigerant leak has been detected from. Based on this notification, the worker recovers the refrigerant from the piping and utilization heat exchanger 32 located between the utilization expansion valve 36 and the shutoff valve 52 from the service port 60 corresponding to the utilization unit 30 in which the refrigerant leak has been detected.

[0079] (3) Features (3-1) The air conditioner 100 comprises a heat source unit 10, a utilization unit 30, connecting pipes 2 and 4, a shutoff valve 52, and a service port 60. The utilization unit 30 is disposed in the air-conditioned space. The connecting pipes 2 and 4 connect the heat source unit 10 and the utilization unit 30. The shutoff valve 52 is disposed outside the air-conditioned space and is provided in the connecting pipe 4. The service port 60 is provided in the connecting pipe 4 between the shutoff valve 52 and the utilization unit 30.

[0080] In the air conditioner 100, the service port 60 is provided closer to the utilization unit 30 than the shutoff valve 52 that shuts off the flow of refrigerant to the utilization unit 30. Therefore, in the air conditioner 100, in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0081] In the air conditioner 100, for example, if the refrigerant sensor 38 detects a so-called slow leak, there is a possibility that a large amount of refrigerant remains in the connecting pipe 4 between the shutoff valve 52 and the utilization unit 30, and this remaining refrigerant can be quickly recovered from the service port 60.

[0082] (3-2) The air conditioner 100 is equipped with a shutoff valve unit 50 having a shutoff valve 52 and a casing 54 that houses the shutoff valve 52. A service port 60 is provided in the shutoff valve unit 50. In this case, when the shutoff valve unit 50 is attached to the connecting pipe 4, the service port 60 can also be provided in the connecting pipe 4, which makes the installation work more efficient.

[0083] In one example, service port 60 is disposed outside casing 54. In this configuration, since service port 60 is disposed outside casing 54, the workability of the refrigerant recovery operation is improved (because there is no need to remove a cover, etc., that covers shutoff valve 52 of casing 54).

[0084] When the service port 60 is disposed outside the casing 54 , it is preferable that the service port 60 be disposed on the side of the casing 54 .

[0085] As for the arrangement of the service port 60 outside the casing 54, it is also possible to provide the service port 60 above and below the casing 54. However, if the service port 60 is provided below the casing, there is a risk that oil will accumulate around the service port 60. Furthermore, if the service port 60 is provided above the casing 54 and the casing 54 housing the shutoff valve 52 is placed above the ceiling, there is a risk that the refrigerant recovery work will be difficult.

[0086] In contrast, by arranging the service port 60 on the side of the casing 54, the problem of oil accumulation can be suppressed and the refrigerant recovery work can be performed more efficiently.

[0087] In another example, the service port 60 is disposed inside the casing 54. In this case, the service port 60 is disposed inside the casing 54 where it does not come into direct contact with the outside air, so that condensation around the service port 60 can be suppressed.

[0088] (3-3) In the air conditioner 100, a shutoff valve 52 is provided in the gas communication pipe (communication pipe 4). In this case, the refrigerant remaining between the utilization expansion valve 36 of the utilization unit 30, which is fully closed when a refrigerant leak is detected, and the shutoff valve 52 can be recovered from the service port 60.

[0089] (3-4) In the air conditioner 100, the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 is 40 m or less. With this configuration, the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 is relatively short (the amount of refrigerant in the communication pipe between the shutoff valve 52 and the utilization unit 30 is relatively small), so even if refrigerant leaks from a refrigerant leakage point in the utilization unit 30 before refrigerant recovery is complete, the refrigerant concentration in the air-conditioned space is unlikely to become high.

[0090] (3-5) In the air conditioner 100, the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 is preferably 2 m or less.

[0091] In such an air conditioner 100, the shutoff valve 52 is provided near the utilization unit 30, so that in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0092] (3-6) In the air conditioner 100 of this embodiment, the utilization unit 30 is of a ceiling-embedded type. The service port 60 is provided in the ceiling space, near an inspection hatch OP of the utilization unit 30 provided in the ceiling.

[0093] In this air conditioner 100, a shutoff valve is provided near the inspection hatch OP for the utilization unit 30, so that if refrigerant leaks from the utilization unit 30, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0094] (3-7) Furthermore, in the air conditioner 100 of this embodiment, the service port 60 may be installed in a position that is accessible from outside the air-conditioned space.

[0095] If a refrigerant leaks from a utilization unit 30, the refrigerant may flow into the air-conditioned space that is the target of air conditioning for that utilization unit 30. In contrast, by making the service port 60 accessible from outside the air-conditioned space, workers can recover the refrigerant without entering the air-conditioned space where the refrigerant may be present, which increases safety.

[0096] (3-8) In one embodiment, the air conditioner 100 includes a plurality of utilization units 30. Each utilization unit 30 is provided with a dedicated shutoff valve 52 and service port 60.

[0097] In this air conditioner 100, if a refrigerant leaks from one of the multiple utilization units 30, the refrigerant can be recovered from the utilization unit 30 from which the refrigerant is leaking, while the other utilization units 30 can continue to operate.

[0098] (4) Variations (4-1) Variation 1A In the above embodiment, the connecting pipe 2 is not provided with a shutoff valve unit 50, but this is not limited to this, and a shutoff valve unit 50 may also be provided in the connecting pipe 2, and a service port 60 may be provided in the connecting pipe 2 between the shutoff valve unit 50 and the utilization unit 30. In this case, if a variable opening motor-operated valve is used as the shutoff valve arranged in the connecting pipe 2, the utilization expansion valve 36 of the utilization unit 30 can be omitted.

[0099] Alternatively, the air conditioner 100 may be provided with a shutoff valve unit 50 having a shutoff valve 52 (e.g., a solenoid valve) that is shut off in the event of a refrigerant leak, while retaining the utilization expansion valve 36 (an electrically operated valve with a variable opening) in the utilization unit 30.

[0100] (4-2) Variation 1B In the above embodiment, each of the utilization units 30 is provided with its own shutoff valve 52 and service port 60, but this is not limiting. For example, a plurality of utilization units 30 may be divided into a plurality of utilization unit 30 groups, each group including two or more utilization units 30, and one shutoff valve 52 and one service port 60 may be provided for each group of utilization units 30. For example, one shutoff valve 52 may be provided on the heat source unit side of the point where the refrigerant pipes extending from each of the utilization units 30 in one group join, and a service port 60 may be provided between this shutoff valve 52 and any of the utilization units 30 in that group.

[0101] Second Embodiment An air conditioner 100A of the second embodiment will be described with reference to the schematic configuration diagrams of FIGS.

[0102] 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 has multiple utilization units 30 that can individually select cooling operation or heating operation, and has an intermediate unit 150 as an example of a shut-off valve unit.

[0103] The air conditioner 100A has many similarities to the air conditioner 100 of the first embodiment, so differences will be mainly described here, and commonalities will not be described unless specifically necessary.

[0104] (1) Overall overview The air conditioner 100A mainly comprises 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 110 and the utilization units 30, a communication pipe that connects the heat source unit 110, the intermediate units 150, and the utilization units 30, and a service port 60 that is arranged in the communication pipe between the expansion valves 152a, 152b of the intermediate units 150 and the utilization units 30.

[0105] In the air conditioner 100A, a refrigerant circuit 190 is configured by connecting the heat source unit 110, the intermediate unit 150, and the utilization units 30 via communication piping.

[0106] The communication pipes include a liquid communication pipe 102a, an intake gas communication pipe 102b, a high- and low-pressure gas communication pipe 102c, a first connection pipe 102d, a second connection pipe 102e, a third connection pipe 102f, and a communication pipe 104b.

[0107] (2) Detailed configuration (2-1) Heat source unit The heat source unit 110 will be described with reference to Fig. 6. Fig. 6 is a refrigerant circuit diagram within the heat source unit 110 of the air conditioner 100A.

[0108] The heat source unit 110 is installed on the roof or in a machine room of the building in which 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. These devices are connected via refrigerant piping to form a part of a refrigerant circuit 190. The heat source unit 110 also includes a heat-source fan 22 and a heat-source control unit 74.

[0109] The gas-side first shut-off valve 119a, the gas-side second shut-off valve 119b, and the liquid-side shut-off valve 119c are manual valves that are opened and closed when charging refrigerant, pumping down, etc. One end of the gas-side first shut-off valve 119a is connected to the suction gas communication pipe 102b, and the other end is connected to a refrigerant pipe extending to the accumulator 20. One end of the gas-side second shut-off valve 119b is connected to the high-low pressure gas communication pipe 102c, and the other end is connected to a 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 a refrigerant pipe extending to the first heat source expansion valve 118a or the second heat source expansion valve 118b.

[0110] 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 shutoff valve 119a and the compressor 12.

[0111] The compressor 12 is the same device as the compressor 12 in the first embodiment, and a detailed description of the compressor 12 will be omitted.

[0112] 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 refrigerant flow 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 a 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 effectively functions as a three-way valve. How the flow path switching valves 14a, 14b, and 14c control the refrigerant flow direction 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.

[0113] The heat source heat exchanger 116 has a configuration similar to that of 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.

[0114] The first heat source expansion valve 118a and the second heat source expansion valve 118b are, for example, motor-operated valves with adjustable openings. 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 shut-off 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 shut-off valve 119c. The openings of the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted according to the situation, and the pressure of the refrigerant passing through them is reduced according to the openings.

[0115] The heat source fan 22 is a device similar to the heat source fan 22 of the first embodiment, and generates an airflow 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.

[0116] The heat source control unit 74 has the same configuration as the heat source control unit 74 in the first embodiment.

[0117] (2-2) Usage 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.

[0118] (2-3) Intermediate unit The intermediate unit 150 is an example of a shutoff valve unit. In the air conditioner 100A, the multiple intermediate units 150 are arranged outside the air-conditioned space. The intermediate units 150 are arranged in the same locations as the shutoff valve units 50 of the first embodiment. Here, to avoid duplication, a description of the installation positions of the intermediate units 150 will be omitted.

[0119] 7, the intermediate units 150 are arranged in the same number as the utilization units 30, so as to correspond one-to-one with any of the utilization units 30. Each intermediate unit 150 is arranged between the corresponding utilization unit 30 (hereinafter referred to as the "corresponding utilization unit") and the heat source unit 110, and switches the flow of refrigerant.

[0120] As shown in FIG. 7, the intermediate unit 150 includes two expansion valves 152a and 152b and a valve control unit .

[0121] The expansion valves 152a and 152b are provided on 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 and 152b are motor-operated valves (electronic expansion valves) that can adjust the opening degree. The expansion valves 152a and 152b are also used as shutoff valves in the event of a refrigerant leak, and have a small leakage amount when closed. For example, the expansion valves 152a and 152b have a leakage amount of 300 cm when closed. 3 / min (air, ΔP = 1.0 MPa) or less.

[0122] The expansion valves 152a, 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 operation of the expansion valves 152a, 152b will be explained later together with the operation of the air conditioner 100A. One end of the expansion valve 152a is connected to the communication pipe 104b extending to the gas end of the utilization heat exchanger 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 extending to the gas end of the utilization heat exchanger 32, and the other end is connected to the third connection pipe 102f.

[0123] The valve control section 76 is structurally similar to the valve control section 76 of the first embodiment. The operation of the controller 70 including the valve control section 76 will be described later.

[0124] (2-4) Connecting piping The liquid communication 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 intake gas communication pipe 102b has one end connected to the gas-side first shutoff valve 119a and the other end connected to second connection pipes 102e extending from each intermediate unit 150. The high-low pressure gas communication pipe 102c has one end connected to the gas-side second shutoff valve 119b and the other end connected to third connection pipes 102f extending from each intermediate unit 150. Each second connection pipe 102e has one end connected to the intake gas communication pipe 102b and the other end connected to a pipe in which an expansion valve 152a of the intermediate unit 150 is disposed. Each third connection pipe 102f has one end connected to the high-low pressure gas communication pipe 102c and the other end connected to a pipe in which an expansion valve 152b of the intermediate unit 150 is disposed. Each of the communication pipes 104b is connected to a pipe of the intermediate unit 150 where a pipe in which an expansion valve 152a is arranged and a pipe in which an expansion valve 152b is arranged join together.

[0125] (2-5) Service port The service port 60 is provided in the communication pipe connecting the heat source unit 110 and the utilization units 30, between the utilization units 30 and the expansion valves 152a, 152b of the intermediate unit 150, which is an example of a shutoff valve unit.

[0126] As for the manner of installation of the service port 60, as in the first embodiment, it may be provided in the connecting piping independent of the intermediate unit 150 (in other words, the shut-off valve unit), but it is preferably provided in the intermediate unit 150 (in the piping that forms part of the intermediate unit 150 and is located closer to the utilization unit 30 than the expansion valves 152a, 152b).

[0127] 9 , if the service port 60 is disposed outside the casing 154 of the intermediate unit 150, work efficiency is improved because the worker can start the refrigerant recovery work without removing a cover or the like that covers the expansion valves 152a, 152b of the intermediate unit 150. In this way, when the service port 60 is disposed outside the casing 154, it is particularly preferable that the service port 60 be disposed on the side of the casing 154.

[0128] Furthermore, if the service port 60 is disposed inside the casing 154 of the intermediate unit 150 as shown by the symbol 60b in FIG. 9, the service port 60 (60b) is not exposed to the surrounding environment, and therefore condensation at the service port 60 can be suppressed.

[0129] If the utilization unit 30 is a ceiling-embedded type, the service port 60 (particularly if the service port 60 is provided in the intermediate unit 150, the intermediate unit 150) is provided in the ceiling space near an inspection hatch OP for the utilization unit 30 that is provided in the ceiling. If the service port 60 is provided separately from the intermediate unit 150, it is preferable that at least the service port 60 is provided in the ceiling space near an inspection hatch OP for the utilization unit 30 that is provided in the ceiling. With this configuration, in the event of a refrigerant leak from the utilization unit 30, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0130] Furthermore, from the viewpoint of worker safety, it is preferable that the service port 60 be located in a position accessible from outside the air-conditioned space. For example, the service port 60 (particularly when the service port 60 is provided in the intermediate unit 150, the intermediate unit 150) is provided in the ceiling space above the corridor adjacent to the air-conditioned space, near an inspection hatch OP provided in the ceiling. If a refrigerant leaks from the utilization unit 30, the refrigerant may flow into the air-conditioned space. In response to this, by arranging the service port 60 in a position accessible from outside the air-conditioned space, workers can recover the refrigerant without entering the air-conditioned space where the refrigerant may be present.

[0131] (2-6) Controller The controller 70 is composed of a usage control unit 72, a heat source control unit 74, and a valve control unit 76. The controller 70 controls the overall operation of the 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.

[0132] FIG. 8 is a control block diagram of the air conditioner 100A in this embodiment.

[0133] 8, the controller 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 controller 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 controller 70 controls the operation of the various devices of the air conditioner 100A based on control signals received by the utilization units 30 from an operation remote control (not shown), measurement signals from the various sensors, etc.

[0134] (3) Refrigerant flow during operation of the air conditioner The flow of refrigerant when the air conditioner 100A is in operation will be explained for each situation, taking as an example the case where the utilization units 30A and 30B in FIG. 7 are in operation.

[0135] In the following description, for the sake of simplicity, it is assumed that the other utilization units 30 are in a stopped state.

[0136] (3-1) When both the utilization unit 30A and the utilization unit 30B are in cooling operation When both the utilization unit 30A and the utilization unit 30B are performing cooling operation, the expansion valve 152a is fully opened and the expansion valve 152b is minimally opened in the intermediate unit 150A corresponding to the utilization unit 30A and the intermediate unit 150B corresponding to the utilization unit 30B. Furthermore, the opening of each utilization expansion valve 36 of the utilization units 30A and 30B is adjusted appropriately, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are fully opened.

[0137] The flow of refrigerant in the refrigerant circuit 190 will now be described. When the compressor 12 starts operating, refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The compressed high-pressure gas refrigerant passes through the discharge pipe, first flow path switching valve 14a, third flow path switching valve 14c, etc., and flows into the heat source heat exchanger 116 where it condenses. The refrigerant that has passed through the heat source heat exchanger 116 passes through the liquid side stop 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 utilization units 30A, 30B.

[0138] The refrigerant that has reached the utilization unit 30A or 30B flows into the utilization expansion valve 36 and is decompressed. The decompressed refrigerant flows into each utilization heat exchanger 32 and evaporates. The refrigerant that has passed through each utilization heat exchanger 32 passes through the connection pipe 104b and flows into the pipe in which the expansion valve 152a of the intermediate unit 150A, 150B is disposed, and reaches the second connection pipe 102e. The refrigerant that has reached the second connection pipe 102e passes through the suction gas connection pipe 102b and flows into the heat source unit 110, and is sucked into the compressor 12 again.

[0139] (3-2) When both the utilization unit 30A and the utilization unit 30B are performing heating operation When both the utilization unit 30A and the utilization unit 30B are performing heating operation, the expansion valves 152a in the intermediate units 150A and 150B are set to the minimum opening and the expansion valves 152b are set to the full opening. Also, the utilization expansion valves 36 in the utilization units 30A and 30B are set to the full opening, and the openings of the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted appropriately.

[0140] The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 starts operating, 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 second flow path switching valve 14b, etc., and flows into the high-low pressure gas communication pipe 102c. The refrigerant that has passed through the high-low pressure gas communication 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 disposed, and then passes through the communication pipe 104b to reach the utilization unit 30A or 30b.

[0141] The refrigerant that has reached the utilization unit 30A or 30B flows into each utilization heat exchanger 32 and condenses. The refrigerant that has passed through each utilization 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.

[0142] 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 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 passes through the first flow path switching valve 14a or the third flow path switching valve 14c and is sucked into the compressor 12 again.

[0143] (3-3) When either the utilization unit 30A or the utilization unit 30B performs cooling operation and the other performs heating operation For example, when the utilization unit 30A performs cooling operation and the utilization unit 30B performs 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. Also, the opening degree of the utilization expansion valve 36 of the utilization unit 30A is adjusted appropriately. 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 valve 36 of the utilization unit 30B is fully opened. And the opening degrees of the first heat source expansion valve 118a and the second heat source expansion valve 118b are adjusted appropriately.

[0144] The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 is operating, refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The high-pressure gas refrigerant compressed by the compressor 12 passes through the discharge pipe, the second flow path switching valve 14b, etc., and flows into the high-low pressure gas communication pipe 102c. The refrigerant that has passed through the high-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 arranged, and flows into the communication pipe 104b.

[0145] The refrigerant that has passed through the connection pipe 104b reaches the utilization unit 30B, and flows into the utilization heat exchanger 32 where it is condensed. The condensed refrigerant passes through the first connection pipe 102d, flows into the first connection pipe 102d that is connected to the utilization unit 30A, and reaches the utilization unit 30A.

[0146] The refrigerant that has reached the utilization unit 30A flows into the utilization expansion valve 36 and is decompressed according to the opening degree. The decompressed 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 in which the expansion valve 152a is arranged, and reaches the second connection pipe 102e.

[0147] The refrigerant that has reached the second connection pipe 102e passes through the intake gas communication pipe 102b, flows into the heat source unit 110, and is sucked into the compressor 12 again.

[0148] (3-4) Refrigerant leakage prevention function When the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, the controller 70 fully closes the utilization expansion valve 36 of the utilization unit 30 in which the refrigerant leak has been detected and the expansion valves (shut-off valves) 152a, 152b of the intermediate unit 150 corresponding to the utilization unit 30 in which the refrigerant leak has been detected, thereby blocking the flow of refrigerant into the utilization unit 30 from the heat source unit 110 side.

[0149] Even if a refrigerant leak is detected in any of the utilization units 30, the controller 70 does not stop the operation of the compressor 12, and continues the cooling operation / heating operation in the utilization units 30 other than the one in which the refrigerant leak is detected. However, when a refrigerant leak is detected in any of the utilization units 30, the controller 70 may stop the operation of the compressor 12 and also stop the cooling operation / heating operation in the utilization units 30 other than the one in which the refrigerant leak is detected.

[0150] If the refrigerant sensor 38 of any of the utilization units 30 detects a refrigerant leak, a notification is sent, for example, to the operation remote controller, indicating which utilization unit 30 the refrigerant leak has been detected from. Based on this notification, the worker recovers the refrigerant from the piping and utilization heat exchanger 32 located between the utilization expansion valve 36 and the expansion valves 152a, 152b, from the service port 60 corresponding to the utilization unit 30 in which the refrigerant leak has been detected.

[0151] (4) Features (4-1) The air conditioner 100A includes a heat source unit 110, a utilization unit 30, a communication pipe, expansion valves 152a and 152b as an example of shutoff valves, and a service port 60. The utilization unit 30 is disposed in the air-conditioned space. The communication pipe connects the heat source unit 110 and the utilization unit 30. The expansion valves 152a and 152b are disposed outside the air-conditioned space and are provided in the communication pipe (gas-side communication pipe). The service port 60 is provided in the communication pipe between the expansion valves 152a and 152b and the utilization unit 30.

[0152] In the air conditioner 100A, the service port 60 is provided closer to the utilization unit 30 than the expansion valves 152a, 152b that block the flow of refrigerant to the utilization unit 30. Therefore, in the air conditioner 100A, in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0153] In the air conditioner 100A, for example, if the refrigerant sensor 38 detects a so-called slow leak, there is a possibility that a large amount of refrigerant remains in the communication pipe (gas side communication pipe) between the expansion valves 152a, 152b and the utilization unit 30, and this remaining refrigerant can be quickly recovered from the service port 60.

[0154] (4-2) The air conditioner 100A includes an intermediate unit 150 as an example of a shutoff valve unit, which has expansion valves 152a and 152b and a casing 154 that houses the expansion valves 152a and 152b. The service port 60 is provided in the intermediate unit 150.

[0155] In this case, when the intermediate unit 150 is attached to the connecting pipe 4, the service port 60 can also be provided in the connecting pipe 4 at the same time, which makes it possible to improve the efficiency of the installation work.

[0156] In one example, service port 60 (60a) is arranged outside casing 154. When configured in this manner, since service port 60 is arranged outside casing 154, the workability of the refrigerant recovery operation is improved (because it is not necessary to remove covers, etc., that cover expansion valves 152a, 152b of casing 154).

[0157] When the service port 60 is disposed outside the casing 154, it is preferable that the service port 60 be disposed on the side of the casing 154. The reason for this is the same as the reason for disposing the service port 60 on the side of the casing 54 in the first embodiment.

[0158] In another example, the service port 60 (60b) is disposed inside the casing 154. In this case, the service port 60 is disposed inside the casing 154, which does not come into direct contact with the outside air, so that condensation around the service port 60 can be suppressed.

[0159] (4-3) In the air conditioner 100A, the length of the communication pipe between the expansion valves 152a, 152b and the utilization unit 30 is 40 m or less. With this configuration, the length of the communication pipe between the expansion valves 152a, 152b and the utilization unit 30 is relatively short (the amount of refrigerant in the communication pipe between the expansion valves 152a, 152b and the utilization unit 30 is relatively small), so even if refrigerant leaks from a refrigerant leakage point in the utilization unit 30 before refrigerant recovery is complete, the refrigerant concentration in the air-conditioned space is unlikely to become high.

[0160] (4-4) In the air conditioner 100A, it is preferable that the length of the communication pipe between the expansion valves 152a, 152b and the utilization units 30 is 2 m or less.

[0161] In this air conditioner 100A, the expansion valves 152a, 152b are provided near the utilization units 30, so in the event of a refrigerant leak, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0162] (4-5) In the air conditioner 100A of this embodiment, the utilization unit 30 is a ceiling-embedded type. The service port 60 is provided in the ceiling space, near an inspection hatch OP for the utilization unit 30 provided in the ceiling.

[0163] In this air conditioner 100A, a shutoff valve is provided near the inspection hatch OP for the utilization unit 30, so that if refrigerant leaks from the utilization unit 30, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0164] (4-6) In the air conditioner 100A of this embodiment, the service port 60 may be installed in a position that is accessible from outside the air-conditioned space.

[0165] If a refrigerant leaks from a utilization unit 30, the refrigerant may flow into the air-conditioned space that is the target of air conditioning for that utilization unit 30. In contrast, by making the service port 60 accessible from outside the air-conditioned space, workers can recover the refrigerant without entering the air-conditioned space where the refrigerant may be present, which increases safety.

[0166] (4-7) In one embodiment, the air conditioner 100A includes a plurality of utilization units 30. Each utilization unit 30 is provided with its own expansion valves 152a, 152b and service port 60.

[0167] In this air conditioner 100A, if a refrigerant leaks from one of the multiple utilization units 30, the refrigerant can be recovered from the utilization unit 30 from which the refrigerant is leaking, while the other utilization units 30 can continue to operate.

[0168] (4-8) In the air conditioner 100A, the expansion valves 152a and 152b, which are an example of shutoff valves, are flow rate adjustment valves whose opening degree is adjustable.

[0169] In the air conditioner 100A, the expansion valves 152a and 152b also function as flow rate adjustment valves, making it possible to reduce the number of parts.

[0170] (4-9) In the air conditioner 100A, expansion valves 152a and 152b are provided on the gas-side connecting pipe. In this case, the refrigerant remaining between the utilization expansion valve 36 of the utilization unit 30, which is fully closed when a refrigerant leak is detected, and the expansion valves 152a and 152b can be recovered from the service port 60.

[0171] (5) Variations The configurations of Modifications 1A and 1B in the first embodiment are also applicable to the second embodiment.

[0172] (5-1) Variation 2A In the second embodiment, the intermediate unit 150 in which two expansion valves 152a, 152b are arranged on the gas side has been described as an example, but the intermediate unit may have two expansion valves 152a, 152b on the gas side and one valve on the liquid side as well. Specifically, the intermediate unit may be a unit having a total of three expansion valves, including the two expansion valves 152a, 152b and an expansion valve arranged in the first connecting pipe 102d. In this case, in addition to the expansion valves 152a, 152b, the expansion valve arranged in the first connecting pipe 102d of the intermediate unit may function as a shutoff valve that closes in the event of a refrigerant leak.

[0173] (5-2) Variation 2B The air conditioner 100 of the first embodiment is equipped with 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 is equipped with 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 be unitized as in the first and second embodiments. The shutoff valve 52 and the expansion valves 152a, 152b may be attached directly to the connecting pipe.

[0174] <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 as defined in the claims. [Explanation of symbols]

[0175] 4,104b Connecting piping 10,110 Heat source unit 30 usage units 50 Shut-off valve unit 52 Shut-off valve 54,154 casing 60 Service Port 100,100A air conditioner 150 Intermediate unit (Shut-off valve unit) 152a, 152b Expansion valve (shutoff valve) OP inspection hatch [Prior art documents] [Patent documents]

[0176] [Patent Document 1] Japanese Patent Publication No. 2023-50282

Claims

1. A heat source unit (10, 110), a utilization unit (30) disposed in the air-conditioned space; a communication pipe (4, 104b) connecting the heat source unit and the utilization unit; a shutoff valve (52, 152a, 152b) disposed outside the air-conditioned space and provided in the connecting pipe; a service port (60) provided in the communication pipe between the shutoff valve and the utilization unit; An air conditioner (100, 100A) comprising:

2. a shutoff valve unit (50, 150) having the shutoff valve and a casing (54, 154) that houses the shutoff valve; the service port is provided in the shutoff valve unit, The service port is disposed outside the casing. The air conditioner according to claim 1.

3. The service port is disposed on a side of the casing. The air conditioner according to claim 2.

4. a shutoff valve unit (50, 150) having the shutoff valve and a casing (54, 154) that houses the shutoff valve; the service port is provided in the shutoff valve unit, The service port is disposed within the casing. The air conditioner according to claim 1.

5. The shutoff valves (152a, 152b) are flow rate adjusting valves whose opening degree can be adjusted. The air conditioner according to any one of claims 1 to 4.

6. The shutoff valve (52, 152a, 152b) is provided in a gas communication pipe (4, 104b) connecting the heat source unit and the utilization unit. The air conditioner according to any one of claims 1 to 4.

7. The length of the communication pipe between the shutoff valve and the utilization unit is 2 m or less. The air conditioner according to any one of claims 1 to 4.

8. The utilization unit is a ceiling-embedded type, The service port is provided in the ceiling space near an inspection hatch (OP) of the utilization unit provided in the ceiling. The air conditioner according to claim 7.

9. The length of the communication pipe between the shutoff valve and the utilization unit is 40 m or less. The air conditioner according to any one of claims 1 to 4.

10. The service port is installed at a position accessible from outside the air-conditioned space. The air conditioner according to any one of claims 1 to 4.

11. A plurality of the utilization units are provided, Each of the utilization units is provided with its own shutoff valve and service port. The air conditioner according to any one of claims 1 to 4.

Images