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] 2. Description of the Related Art Conventionally, as disclosed in Patent Document 1 (JP Patent Publication No. 2023-50282), 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 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 an 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 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, since the service port is provided in the shutoff valve unit, when the shutoff valve unit is attached to the connecting pipe, the service port can also be provided in the connecting pipe at the same time, which makes the installation work more efficient. Also, in this air conditioner, since the service port is located outside the casing, the workability of the refrigerant recovery work is high.

[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 below or above the casing. However, if the service port is located below the casing, there is a risk that oil will accumulate at the service port. Also, if the service port is located above the casing and the casing housing the shutoff valve is located above the ceiling, it may be difficult to recover the refrigerant.

[0010] In contrast, 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, because the service port is provided inside the casing, the occurrence of 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 aspect to the fourth aspect, in which the shutoff valve is a flow rate adjustment valve whose opening degree is adjustable.

[0014] In the air conditioner of the fifth aspect, since the shutoff valve also functions as a flow rate adjustment valve, it is possible to reduce the number of parts.

[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 aspect to the sixth aspect, in which the length of the communication 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 in the vicinity of 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 air conditioner according to an eighth aspect is the air conditioner according to any one of the first to seventh aspects, in which 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. Therefore, 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, in which the length of the communication 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 that even if refrigerant leaks from a refrigerant leakage point in the utilization unit before refrigerant recovery is completed, 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, there is a risk that the refrigerant will 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, since the service port is 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 provides 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 a 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 description of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic configuration diagram of an air conditioner according to a first embodiment. [Diagram 2] FIG. 2 is a control block diagram of the air conditioner of FIG. [Diagram 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. [Diagram 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. 11 is a diagram of a refrigerant circuit in a heat source unit of an air conditioner according to a second embodiment. [Figure 7] FIG. 11 is a refrigerant circuit diagram of a portion other than the heat source unit of an air conditioner according to a second embodiment. [Figure 8] FIG. 11 is a control block diagram of an air conditioner according to a second embodiment. [Figure 9] FIG. 11 is a schematic perspective view of a shutoff valve unit of an air conditioner according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 a plurality of air-conditioned spaces in a building. The air conditioner 100 mainly has a heat source unit 10, a plurality of utilization units 30, a shutoff valve unit 50 and a service port 60 provided for each of the plurality of 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] The heat source unit 10 and the utilization unit 30 are connected by the interconnection pipes 2 and 4, as shown in FIG. 1. The heat source unit 10 and the utilization unit 30 are connected by the interconnection 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, and the like, which will be described later. The shutoff valve unit 50 is provided in the interconnection pipe 4, as shown in FIG. 1. The interconnection pipe 4 is a gas interconnection 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. A service port 60 for recovering the refrigerant is provided in the interconnection pipe 4 between the shutoff valve 52 of the shutoff valve unit 50 and the utilization unit 30. The 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 an air-conditioned space that is to be air-conditioned. The utilization 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 taking the utilization unit 30 as a ceiling-embedded type as an example.

[0033] The 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.

[0034] 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 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 degree. The utilization expansion valve 36 is also used as a shutoff valve in the event of a refrigerant leak, and is a valve that has 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 leakage of the refrigerant and is provided, for example, near the utilization heat exchanger 32.

[0038] The usage control unit 72 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 processing according to the program, thereby cooperating with a heat source control unit 74 of the heat source unit 10 and a valve control unit 76 of the shutoff valve unit 50 to control the operation of various devices of 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 rooftop or in a machine room of a building in which an 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.

[0040] 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 connection 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 part between the liquid refrigerant pipe 28d and the connection pipe 2. The gas refrigerant pipe 28e connects the flow path switching valve 14 and the connection pipe 4. The gas stop valve 26 is provided at the connection part 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 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 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 flow path of the refrigerant between a first state and a second state. In the first state, the flow path switching valve 14 communicates the suction pipe 28a with the gas refrigerant pipe 28e and the discharge pipe 28b with the gas refrigerant pipe 28c, as shown by solid lines in the flow path switching valve 14 in Fig. 1. In the second state, the flow path switching valve 14 communicates the suction pipe 28a with the gas refrigerant pipe 28c and the discharge pipe 28b with the gas refrigerant pipe 28e, as shown by 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 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 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 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 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 a container provided in the suction pipe 28a and has a gas-liquid separation function that separates the refrigerant flowing in into a gas refrigerant and a liquid refrigerant. The refrigerant flowing in to the accumulator 20 is separated into a gas refrigerant and a 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 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 predetermined arithmetic processing in accordance with the program, thereby cooperating 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 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 when, for example, a refrigerant leaks from the corresponding utilization unit 30.

[0051] The shutoff valve unit 50 is disposed outside the air-conditioned space. For example, the shutoff valve unit 50 is disposed 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 disposed 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 location exemplified above, and the shutoff valve unit 50 may be disposed 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 whose opening degree can be adjusted.

[0054] The length of the communication piping between the shutoff valve 52 and the utilization unit 30 (the total length of the piping on the utilization unit 30 side of the shutoff valve 52 in the shutoff valve unit 50 and the communication piping 4 connecting the shutoff valve unit 50 and the utilization unit 30) is preferably 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 piping length included in the refrigerant recovery portion is relatively short and the amount of refrigerant in the piping is relatively small, so that the refrigerant concentration in the air-conditioned space is unlikely to become high.

[0055] Moreover, 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 the 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 dew-proof material is disposed inside the casing 54, which suppresses condensation around the shutoff valve 52.

[0057] 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 predetermined arithmetic processing in accordance with the program, thereby cooperating with a usage control unit 72 of the usage unit 30 and a 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 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 refrigerant, a refrigerant recovery container is connected to the service port 60 via connecting parts and a hose, and the refrigerant is recovered in 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 is provided in the shutoff valve unit 50 (in the piping that constitutes part of the shutoff valve unit 50 and that is located on the utilization unit 30 side relative to 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, whereas if the service port 60 is incorporated in 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 shut-off valve unit 50, as shown by the solid line in FIG. 3, an operator can start the refrigerant recovery operation without removing a cover or the like covering the shut-off valve 52 of the shut-off valve unit 50, thereby improving 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 at a position that is accessible to an operator from the side of the casing 54.

[0063] For example, the service port 60 may be disposed above the casing 54, at a position accessible to an operator from above the casing 54. In this case, however, if the shutoff valve unit 50 is installed in the attic space, it may be difficult for an operator to access it. The service port 60 may also be disposed below the casing 54, but in this case, if the shutoff valve unit 50 is installed in the attic space, there is a risk of oil pooling in the service port 60 area.

[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 while improving the workability of refrigerant recovery.

[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 FIG. 3, it will be necessary to remove the cover covering 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] When the utilization unit 30 is a ceiling-embedded type, the service port 60 (when the shutoff valve unit 50 is provided with the service port 60, the shutoff valve unit 50) is provided in the ceiling space near the inspection hatch OP of the utilization unit 30 provided in the ceiling. Near the inspection hatch OP of the utilization unit 30 means a distance (e.g., 50 cm) where the service port 60 can be reached from the inspection hatch OP. When the service port 60 is provided separately from the shutoff valve unit 50, it is preferable that at least the service port 60 is provided in the ceiling space near the inspection hatch OP of the utilization unit 30 provided in the ceiling. With this configuration, when a refrigerant leaks from the utilization unit 30, the refrigerant can be quickly collected from the utilization unit 30 from which the refrigerant is leaking.

[0067] From the viewpoint of worker safety, the service port 60 is preferably disposed at 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 of a 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 the refrigerant leaks from the utilization unit 30, the refrigerant may flow into the air-conditioned space. In response to this, by disposing the service port 60 at a position accessible from outside the air-conditioned space, the worker can collect 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 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.

[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 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 controller 70 is also electrically connected to various sensors that measure the temperature and pressure of the refrigerant, the air temperature in the air-conditioned space, the outside air temperature, etc. The controller 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 the various sensors.

[0071] The controller 70 mainly performs cooling operation and heating operation. The controller 70 also has a function of preventing 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 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 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 (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, and condenses through heat exchange with the air around the heat source unit 10 supplied by the heat source fan 22 to become 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 gas-liquid two-phase refrigerant exchanges heat with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34 in the utilization heat exchanger 32, evaporates, and becomes 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 flows 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 out into the air-conditioned space.

[0074] (2-5-2) Heating operation When the controller 70 receives an instruction to perform heating operation from, for example, an operation 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. Also, 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 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 sucked 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, and condenses through heat exchange with the air in the air-conditioned space supplied to the utilization heat exchanger 32 by the utilization fan 34, becoming a 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 out 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 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, and evaporates, becoming 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 into the compressor 12 again.

[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 flow of refrigerant into the utilization unit 30 through the connecting piping 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, for example, a notification is sent to the operation remote control as to which utilization unit 30 the refrigerant leak has been detected from. Based on this notification, the worker recovers the refrigerant in the piping and utilization heat exchanger 32 disposed 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 includes 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 case of a refrigerant leak, the air conditioner 100 can quickly recover the refrigerant from the utilization unit 30 from which the refrigerant is leaking.

[0081] In the air conditioner 100, for example, when 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 piping 4, the service port 60 can also be provided in the connecting piping 4, thereby making the installation work more efficient.

[0083] In one example, the service port 60 is disposed outside the casing 54. When configured in this manner, since the service port 60 is disposed outside the casing 54, the workability of the refrigerant recovery operation is improved (since it is not necessary to remove a cover, etc., of the casing 54 that covers the shutoff valve 52).

[0084] When the service port 60 is disposed outside the casing 54 , the service port 60 is preferably 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 below and above the casing 54. However, if the service port 60 is provided below the casing, there is a risk that oil will accumulate at 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 it will be difficult to perform the refrigerant recovery work.

[0086] In contrast, by arranging the service port 60 on the side of the casing 54, the problem of oil accumulation can be suppressed while improving the workability of refrigerant recovery.

[0087] In another example, the service port 60 is disposed inside the casing 54. In this case, since the service port 60 is disposed inside the casing 54 where it does not come into direct contact with the outside air, the occurrence of 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 connection pipe (connection 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, since the length of the communication pipe between the shutoff valve 52 and the utilization unit 30 is relatively short (since the amount of refrigerant in the communication pipe between the shutoff valve 52 and the utilization unit 30 is relatively small), even if refrigerant leaks from a refrigerant leakage point in the utilization unit 30 before refrigerant recovery is completed, 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, since the shutoff valve 52 is provided near the utilization unit 30, 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 space above the ceiling, 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 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.

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

[0095] If a refrigerant leaks from the utilization unit 30, there is a risk that the refrigerant will flow into the air-conditioned space that is the target of air conditioning of that utilization unit 30. In response to this, 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 is very safe.

[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 a service port 60.

[0097] In this air conditioner 100, if a refrigerant leaks from one of the multiple utilization units 30, refrigerant recovery can be performed for 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 interconnecting pipe 2 is not provided with the shutoff valve unit 50, but the present invention is not limited to this. The interconnecting pipe 2 may also be provided with a shutoff valve unit 50, and a service port 60 may be provided in the interconnecting 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 interconnecting pipe 2, the utilization expansion valve 36 of the utilization unit 30 can be omitted.

[0099] Alternatively, in the air conditioner 100, the utilization unit 30 may be provided with a utilization expansion valve 36 (an electrically-operated valve with a variable opening), and may further 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.

[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 limited thereto. For example, a plurality of utilization units 30 may be divided into a plurality of utilization unit 30 groups each 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 a plurality of utilization units 30 that can individually select cooling operation or heating operation, and has an intermediate unit 150 as an example of a shutoff valve unit.

[0103] Incidentally, since the air conditioner 100A has many similarities to the air conditioner 100 of the first embodiment, the differences will be mainly described here, and a description of the commonalities will be omitted unless particularly 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 unit 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 unit 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 connection pipes include a liquid connection pipe 102a, an intake gas connection pipe 102b, a high and low pressure gas connection pipe 102c, a first connection pipe 102d, a second connection pipe 102e, a third connection pipe 102f, and a connection pipe 104b.

[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 rooftop or in a machine room of the building in which the air conditioner 100 is installed. The heat source unit 110 mainly includes a gas-side first shutoff valve 119a, a gas-side second 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 a refrigerant pipe 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.

[0109] 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 extending 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 extending 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 extending to the first heat source expansion valve 118a or the second heat source expansion valve 118b.

[0110] The accumulator 20 is a device similar to the accumulator 20 in the first embodiment. The accumulator 20 is disposed between the gas-side first shutoff valve 119a and the compressor 12.

[0111] The compressor 12 is the same device as the compressor 12 in the first embodiment. 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 flow of the 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 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 the 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 flow of the refrigerant in the air conditioner 100A.

[0113] 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.

[0114] The first heat source expansion valve 118a and the second heat source expansion valve 118b are, for example, motor-operated 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 exchanger 116a, and the other end is connected to a refrigerant pipe extending to the liquid side shutoff valve 119c. One end of the second heat source expansion valve 118b is connected to a refrigerant pipe extending from the second heat exchanger 116b, and the other end is connected to a refrigerant pipe extending to the liquid side shutoff 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.

[0115] The heat source fan 22 is a device similar to the heat source fan 22 in 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 location as the shutoff valve units 50 of the first embodiment. Here, in order to avoid duplication of description, a description of the installation position of the intermediate units 150 is 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 a "corresponding utilization unit") and the heat source unit 110, and switches the flow of the refrigerant.

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

[0121] The expansion valves 152a, 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, 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 have a leakage amount of 300 cm when closed. 3 / min (air, ΔP = 1.0 MPa) or less.

[0122] 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 according to the situation. The movement of the expansion valves 152a and 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 connection 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 connection 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 the second connection pipe 102e extending from each intermediate unit 150. The high and low pressure gas communication 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 communication pipe 102b and the other end connected to the pipe in which the expansion valve 152a of the intermediate unit 150 is arranged. Each third connection pipe 102f has one end connected to the high and low pressure gas communication pipe 102c and the other end connected to the pipe in which the expansion valve 152b of the intermediate unit 150 is arranged. Each communication pipe 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 preferable that it is provided in the intermediate unit 150 (in the piping that constitutes part of the intermediate unit 150 and is located on the utilization unit 30 side relative to the expansion valves 152a, 152b).

[0127] 9 , an operator can start the refrigerant recovery operation without removing a cover or the like covering the expansion valves 152a, 152b of the intermediate unit 150, which improves workability. When the service port 60 is arranged outside the casing 154 in this way, it is particularly preferable that the service port 60 be arranged 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 indicated by reference symbol 60b in FIG. 9, the service port 60 (60b) is not exposed to the surrounding environment, so that the occurrence of condensation at the service port 60 can be suppressed.

[0129] When the utilization unit 30 is of the ceiling embedded type, 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 near an inspection hatch OP for the utilization unit 30 provided in the ceiling. When 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 provided in the ceiling. With this configuration, when a refrigerant leaks from the utilization unit 30, the refrigerant can be quickly recovered from the utilization unit 30 from which the refrigerant is leaking.

[0130] From the viewpoint of worker safety, the service port 60 is preferably disposed 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 of a corridor adjacent to the air-conditioned space, near an inspection hatch OP provided in the ceiling. If the refrigerant leaks from the utilization unit 30, the refrigerant may flow into the air-conditioned space. In response to this, by disposing the service port 60 in a position accessible from outside the air-conditioned space, workers can collect 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 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 the 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 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 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, and the like. The controller 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), measurement signals of various sensors, and the like.

[0134] (3) Refrigerant flow during operation of the air conditioner The flow of refrigerant when the air conditioner 100A is in operation will be described for each situation, taking as an example a case in which 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 perform cooling operation When both the utilization unit 30A and the utilization unit 30B perform cooling operation, in the intermediate unit 150A corresponding to the utilization unit 30A and the intermediate unit 150B corresponding to the utilization unit 30B, the expansion valve 152a is fully opened and the expansion valve 152b is minimally opened. In addition, the opening degree of each utilization expansion valve 36 of the utilization units 30A and 30B is appropriately adjusted, 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 be described. When the compressor 12 starts operating, the refrigerant is sucked into the compressor 12 through a suction pipe and compressed. The compressed high-pressure gas refrigerant passes through a 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 where it is condensed. 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 depressurized. The depressurized refrigerant flows into each utilization heat exchanger 32 and evaporates. The refrigerant that has passed through each utilization heat exchanger 32 flows through the connection pipe 104b 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 flows into the heat source unit 110 through the suction gas connection pipe 102b, 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 perform heating operation, in the intermediate units 150A and 150B, the expansion valves 152a are opened to a minimum degree, and the expansion valves 152b are opened fully. Also, the utilization expansion valves 36 of the utilization units 30A and 30B are opened fully, and the first heat source expansion valve 118a and the second heat source expansion valve 118b are appropriately adjusted in opening degree.

[0140] 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 second flow path switching valve 14b, etc., and flows into the high- and low-pressure gas communication pipe 102c. 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 reached the third connection pipe 102f flows into the pipe in which the expansion valve 152b of the intermediate unit 150A or 150B is arranged, 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 at a minimum opening. Also, the utilization expansion valve 36 of the utilization unit 30A has its opening adjusted appropriately. 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 valve 36 of the utilization unit 30B is fully opened. And the first heat source expansion valve 118a and the second heat source expansion valve 118b have their opening adjusted appropriately.

[0144] The flow of refrigerant in the refrigerant circuit 190 will be described. When the compressor 12 is operated, the refrigerant is sucked into the compressor 12 through the suction pipe and compressed. The high-pressure gas refrigerant compressed by the compressor 12 flows into the high-low pressure gas communication pipe 102c through the discharge pipe and the second flow path switching valve 14b. 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 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 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 suction 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 (shutoff 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, for example, a notification is sent to the operation remote control as to which utilization unit 30 the refrigerant leak has been detected from. Based on this notification, the worker recovers the refrigerant in the piping and utilization heat exchanger 32 disposed 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, 152b as an example of a shutoff valve, and a service port 60. The utilization unit 30 is disposed in an air-conditioned space. The communication pipe connects the heat source unit 110 and the utilization unit 30. The expansion valves 152a, 152b are disposed outside the air-conditioned space and provided in the communication pipe (gas-side communication pipe). The service port 60 is provided in the communication pipe between the expansion valves 152a, 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, when the refrigerant sensor 38 detects a so-called slow leak, there is a possibility that a large amount of refrigerant remains in the connecting piping (gas side connecting piping) 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, 152b and a casing 154 that houses the expansion valves 152a, 152b. The intermediate unit 150 is provided with a service port 60.

[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, so that the efficiency of the installation work can be improved.

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

[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 where it does not come into direct contact with the outside air, so that the occurrence of 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, since the length of the communication pipe between the expansion valves 152a, 152b and the utilization unit 30 is relatively short (since the amount of refrigerant in the communication pipe between the expansion valves 152a, 152b and the utilization unit 30 is relatively small), even if refrigerant leaks from a refrigerant leakage point in the utilization unit 30 before refrigerant recovery is completed, 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 pipes 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 in the vicinity of 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.

[0162] (4-5) In the air conditioner 100A 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.

[0163] In this air conditioner 100A, a shutoff valve is provided near the inspection hatch OP for the utilization unit 30. Therefore, 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.

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

[0165] If a refrigerant leaks from the utilization unit 30, there is a risk that the refrigerant will flow into the air-conditioned space that is the target of air conditioning of that utilization unit 30. In response to this, 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 is very safe.

[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 a service port 60.

[0167] In this air conditioner 100A, if a refrigerant leaks from one of the multiple utilization units 30, 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 a shutoff valve, 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, the expansion valves 152a and 152b are provided on the gas side communication 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 the 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. Specifically, the intermediate unit may be a unit having a total of three expansion valves, including an expansion valve arranged on the first connecting pipe 102d in addition to the two expansion valves 152a, 152b. In this case, in addition to the expansion valves 152a, 152b, the expansion valve arranged on the first connecting pipe 102d of the intermediate unit may function as a shutoff valve that is closed when a refrigerant leaks.

[0173] (5-2) Variation 2B 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.

[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 described 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] JP 2023-50282 A

Claims

1. A heat source unit (10, 110), A utilization unit (30) disposed in the air-conditioned space; A communication pipe (4, 104b) that connects the heat source unit and the utilization unit; A shutoff valve (52, 152a, 152b) disposed outside the air-conditioned space and provided in the communication 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.

2. The air conditioner according to claim 1.

3. The service port is disposed on a side of the casing.

3. 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.

2. 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. An 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 opening (OP) of the utilization unit provided in the ceiling.

8. An 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. An 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