ES3048190T3 - Air conditioning apparatus - Google Patents

Abstract

An air conditioning unit on the use side (3a, 3b) comprises: a housing (31a, 31b); a use-side heat exchanger (33a, 33b) for cooling or heating the air inside the housing (31a, 31b) using a refrigerant supplied from a heat source-side air conditioning unit (2); an air supply/exhaust mechanism for taking in ambient and/or outside air from an air-conditioned space or from outside the space, supplying it as supply air to the air-conditioned space, and expelling it as exhaust air from the air-conditioned space; and a refrigerant leak detection device (48a, 48b) for detecting the refrigerant. When the refrigerant leak detection device (48a, 48b) detects the refrigerant, the air supply/exhaust mechanism performs an exhaust operation to expel the refrigerant from the air-conditioned space along with the air inside the housing (31a, 31b). (Automatic translation using Google Translate, not legally binding)

Description

[0001] DESCRIPTION

[0003] Air conditioning unit

[0005] Technical field

[0007] The present invention relates to an air conditioning apparatus provided with a use-side air conditioning apparatus, and in particular relates to: an air conditioning apparatus provided with a use-side air conditioning apparatus having a use-side heat exchanger for cooling or heating air inside a housing by means of a refrigerant supplied from a heat source-side air conditioning apparatus, and an air supply/extraction mechanism for bringing air into the housing from an air-conditioned space or from outside an air-conditioned space and/or for supplying air from inside the housing to the air-conditioned space or outside the air-conditioned space.

[0009] Background of the technique

[0011] In the past, there have been ventilation air conditioners (use-side air conditioning appliances) having an evaporator and/or a condenser (use-side heat exchangers) for cooling or heating the air inside a housing by means of a refrigerant supplied from an outside machine (a heat source-side air conditioning appliance) and an air supply fan and/or an air exhaust fan (air supply/exhaust mechanism) for bringing air into the housing from an air-conditioned space or from outside an air-conditioned space and/or for supplying air from inside the housing to the air-conditioned space or outside the air-conditioned space, as disclosed in patent bibliography 1 (Japanese patent pending publication no. 2000-220877).

[0012] Another example of the above technique can be seen in document JP H09324928.

[0014] Compendium of the invention

[0016] In an air conditioning appliance of this type on the use side which has a ventilation air conditioning function for ventilating and conditioning the interior of a room, when there are refrigerant leaks, there is a risk that the leaked refrigerant will be supplied to the air-conditioned space and that an oxygen deficiency accident, an ignition accident (when the refrigerant is slightly flammable or flammable) or a poisoning accident (when the refrigerant is toxic) will occur.

[0018] An object of the present invention is to ensure that when a refrigerant leak occurs in an air conditioning appliance on the use side having a ventilation air conditioning function and an air conditioning appliance provided with the same, the leaked refrigerant is quickly expelled and not supplied to an air-conditioned space.

[0020] An air conditioning apparatus provided with a plurality of use-side air conditioning apparatus according to a first aspect of the present invention is defined in claim 1.

[0022] In this respect, when a refrigerant leak has occurred, the leaked refrigerant can be quickly expelled and prevented from being supplied to the air-conditioned space, using the air supply/extraction mechanism.

[0024] In the load-side air conditioning unit, according to the first aspect, the load-side heat exchanger is configured to connect to the heat source-side air conditioning unit via a refrigerant interconnecting pipe. In this aspect, a gasket is provided within each housing for connecting the load-side heat exchanger to the refrigerant interconnecting pipe.

[0026] In this respect, when refrigerant leaks from the joint connecting the heat exchanger on the load side to the refrigerant interconnecting pipe, the refrigerant leaks into the casing. Therefore, when a refrigerant leak occurs, it can be detected quickly, and the leaked refrigerant can be expelled promptly.

[0028] An air conditioning unit provided with a load-side air conditioning unit according to a second aspect is the load-side air conditioning unit according to the first aspect, wherein a complete heat exchanger is provided within the housing for effecting heat exchange between the outside air and the ambient air, and the air supply/extraction mechanism has a first air supply turbine provided for drawing outside air from outside the air-conditioned space and supplying the air to the air-conditioned space, and a first air extraction turbine provided for drawing ambient air from the air-conditioned space and extracting the exhaust air from the air-conditioned space. In this aspect, the first air extraction turbine is configured to perform the refrigerant expulsion operation.

[0029] In this respect, when a refrigerant leak has occurred, the leaked refrigerant can be quickly expelled and prevented from being supplied to the air-conditioned space by activating the first air extraction turbine, thus configuring the air supply/extraction mechanism.

[0031] An air conditioning unit according to a third aspect is an air conditioning unit according to the first aspect, wherein the air supply/extraction mechanism has an air supply/extraction turbine provided to be able to switch between an air supply state of drawing ambient air from the air-conditioned space, drawing outside air from outside the air-conditioned space and supplying the supply air to the air-conditioned space, and an air extraction state of expelling the exhaust air from the air-conditioned space. In this aspect, the air supply/extraction turbine in the air extraction state is configured to perform the refrigerant expulsion operation.

[0033] In this respect, when a refrigerant leak has occurred, the leaked refrigerant can be quickly expelled and prevented from being supplied to the air-conditioned space by running the air supply/extraction turbine by setting the air supply/extraction mechanism to the air extraction state.

[0035] An air conditioning unit provided according to a fourth aspect is the air conditioning unit according to the first aspect, wherein the air supply/extraction mechanism has a second air supply turbine provided to be able to draw ambient air from the air-conditioned space, draw outside air from outside the air-conditioned space, and supply the supply air to the air-conditioned space, and a second air extraction turbine provided to be able to extract exhaust air from the air-conditioned space. In this aspect, the second air extraction turbine is configured to perform the refrigerant expulsion operation.

[0037] In this respect, when a refrigerant leak has occurred, the leaked refrigerant can be quickly expelled and prevented from being supplied to the air-conditioned space by operating the second air extraction turbine, configuring the air supply/extraction mechanism.

[0039] An air conditioning unit according to a fifth aspect is an air conditioning unit according to the first aspect wherein the air supply/extraction mechanism has a third air supply turbine provided to be able to draw outside air from outside the air-conditioned space and supply supply air to the air-conditioned space, and a third air extraction turbine provided to be able to draw ambient air from the air-conditioned space, return part of the ambient air to the outside air drawn in by the third air supply turbine, and expel the remainder of the ambient air as exhaust air from the air-conditioned space. In this aspect, the third air extraction turbine is configured to perform the refrigerant expulsion operation.

[0041] In this respect, when a refrigerant leak has occurred, the leaked refrigerant can be quickly expelled and prevented from being supplied to the air-conditioned space by operating the third air extraction turbine configuring the air supply/extraction mechanism.

[0043] An air conditioning apparatus provided with a use-side air conditioning apparatus according to an aspect not part of the invention is the use-side air conditioning apparatus according to any of aspects 1 to 5, wherein the use-side heat exchanger is connected to the heat source-side air conditioning apparatus via the refrigerant interconnecting pipe, and a gasket is provided outside the housing for connecting the use-side heat exchanger to the refrigerant interconnecting pipe. In this respect, the air supply/extraction mechanism has an indoor-outdoor communication mechanism capable of switching between an indoor-outdoor communication state to allow communication between the inside of the housing and an installation space on the use side where the housing is provided, and a non-indoor-outdoor communication state that does not allow communication between the inside of the housing and the installation space on the use side, and the refrigerant expulsion operation is performed by putting the indoor-outdoor communication mechanism into the indoor-outdoor communication state.

[0045] In this aspect, when refrigerant leaks through the joint connecting the load-side heat exchanger to the refrigerant interconnecting pipe, the refrigerant leaks into the load-side installation space. However, in this aspect, the load-side installation space and the inside of the housing may be allowed to communicate via the inside-outside communication mechanism. Therefore, in this aspect, when a refrigerant leak occurs, the refrigerant that has leaked into the load-side installation space can be quickly expelled while being guided into the inside of the housing, and its supply to the air-conditioned space is prevented, using the air supply/extraction mechanism that includes the inside-outside communication mechanism.

[0047] An air conditioning apparatus according to a sixth aspect is the air conditioning apparatus according to any of the first to fifth aspects, wherein the refrigerant is denser than air; and the refrigerant leak detection device is provided on a lower part of the housing.

[0049] In this respect, the refrigerant can be detected quickly using the tendency of refrigerant denser than air to accumulate downwards.

[0051] An air conditioning apparatus according to a seventh aspect is the air conditioning apparatus according to any of the first to fifth aspects in which the refrigerant is less dense than air; and the refrigerant leak detection device is provided on a top of the housing.

[0053] In this respect, the refrigerant can be detected quickly using the tendency of the refrigerant, which is less dense than air, to accumulate upwards.

[0055] An air conditioning apparatus according to an eighth aspect is the air conditioning apparatus according to any of the first to seventh aspects comprising the refrigerant, the refrigerant being flammable or slightly flammable.

[0057] In this respect, the incidence of ignition accidents in the air-conditioned space can be suppressed.

[0058] An air conditioning apparatus according to a ninth aspect is the air conditioning apparatus according to any of aspects one through seven comprising the refrigerant, the refrigerant being toxic.

[0059] In this respect, the incidence of accidents due to poisoning in the air-conditioned space can be suppressed.

[0061] An air conditioning apparatus according to a tenth aspect is the air conditioning apparatus according to any of the first to seventh aspects comprising the refrigerant, the refrigerant not being flammable, slightly flammable, or toxic.

[0063] In this respect, the incidence of accidents due to oxygen deficiency in the air-conditioned space can be suppressed.

[0065] An air conditioning apparatus according to the invention comprises a plurality of use-side air conditioning apparatuses.

[0067] In this respect, when refrigerant has leaked in any of the plurality of air conditioning appliances on the use side, the leaking refrigerant can be quickly expelled using the air supply/extraction mechanism of the air conditioning appliance on the use side in which the refrigerant has leaked, and the supply of refrigerant to the air-conditioned space being air-conditioned by the air conditioning appliance on the use side in which the refrigerant has leaked can be prevented.

[0069] Brief description of the drawings

[0071] FIG. 1 is a general configuration diagram of an air conditioning apparatus according to a first embodiment of the present invention (airflow during normal operation and the like are also illustrated);

[0073] FIG. 2 is a control block diagram of the air conditioning apparatus of the first embodiment;

[0074] FIG. 3 is a diagram showing the airflow during a refrigerant expulsion operation and the like in the first embodiment;

[0076] FIG.4 is a general configuration diagram of the air conditioning apparatus on the use side according to a modification of the first embodiment and of an air conditioning apparatus not part of the invention provided with the same (airflow during normal operation and the like are also illustrated);

[0078] FIG. 5 is a diagram showing the airflow during a coolant expulsion operation and the like in a modification of the first embodiment that is not part of the invention;

[0080] FIG. 6 is a general configuration diagram of an air conditioning apparatus according to a second embodiment of the present invention (airflow during normal operation and the like are also illustrated);

[0082] FIG. 7 is a control block diagram of the air conditioning unit of the second embodiment; FIGURE 8 is a diagram showing the airflow during a refrigerant expulsion operation and the like in the second embodiment;

[0083] FIG. 9 is a general configuration diagram of an air conditioning apparatus according to a third embodiment of the invention (the airflow during normal operation and the like are also illustrated); FIG. 10 is a control block diagram of the air conditioning apparatus of the third embodiment; FIG. 11 is a diagram showing the airflow during a refrigerant expulsion operation and the like in the third embodiment;

[0084] FIG. 12 is a general configuration diagram of an air conditioning apparatus according to a fourth embodiment of the present invention, (airflow during normal operation and the like are also illustrated);

[0085] FIG. 13 is a control block diagram of the air conditioning apparatus of the fourth embodiment; and FIG. 14 is a diagram showing the airflow during a refrigerant expulsion operation and the like in the fourth embodiment.

[0086] Description of achievements

[0087] An embodiment of an air conditioning unit according to the invention is described below with reference to the drawings. The specific configuration of an embodiment of the air conditioning unit according to the present invention is not limited to the following embodiments or modifications thereof; the configuration may be changed within the scope of the invention as defined in the appended claims. -First embodiment-(1) Configuration

[0088] FIG. 1 is a general configuration diagram of an air conditioning unit with air conditioning units 3a, 3b on the use side according to a first embodiment of the present invention. FIG. 2 is a control block diagram of air conditioning unit 1 of the first embodiment.

[0089] <Overview>

[0090] Air conditioning appliance 1, which is an air conditioning ventilation system having an air conditioning function to ventilate and condition the interior of a room, mainly has an air conditioning appliance 2 on the heat source side, and a plurality (two in this embodiment) of air conditioning appliances 3a, 3b on the use side.

[0091] Air conditioning unit 1 has a refrigerant circuit 10 through which refrigerant circulates. The refrigerant circuit 10 is configured by connecting the heat source-side air conditioning unit 2 to the use-side air conditioning units 3a and 3b. In this embodiment, the heat source-side air conditioning unit 2 is installed in a location such as the roof of a building, and the use-side air conditioning units 3a and 3b are installed in use-side installation spaces (in this embodiment, use-side installation spaces S3 and S4), such as a building machine room or a space above the roof, corresponding to air-conditioned spaces (in this embodiment, air-conditioned spaces S1 and S2) that are ventilated and conditioned. The heat source-side air conditioning unit 2 and the user-side air conditioning units 3a and 3b are connected via refrigerant interconnecting pipes 11 and 12, thus forming refrigerant circuit 10. The refrigerant sealed within refrigerant circuit 10 is either a mildly flammable refrigerant such as R32, a flammable refrigerant such as propane, or a toxic refrigerant such as ammonia.

[0092] Air conditioning unit 1 has a plurality of air ducts. In this embodiment, air conditioning unit 1 has an intake duct 5 to bring outside air (OA) into the use-side air conditioning units 3a, 3b from outside the air-conditioned spaces S1, S2, supply air ducts 6a, 6b to supply supply air (SA) from the use-side air conditioning units 3a, 3b to the air-conditioned spaces S1, S2, outlet ducts 7a, 7b to take ambient air (RA) from the air-conditioned spaces S1, S2 into the corresponding use-side air conditioning units 3a, 3b, and an exhaust air duct 8 to expel exhaust air (EA) from the air-conditioned spaces S1, S2 of the use-side air conditioning units 3a, 3b. In this way, air can be exchanged between the air-conditioned spaces S1 and S2 and/or the exterior of the air-conditioned spaces S1 and S2 and the air conditioning units 3a and 3b on the occupancy side. The intake duct 5 has intake branch ducts 5a and 5b that connect to the air conditioning units 3a and 3b on the occupancy side, and the exhaust duct 8 has exhaust branch ducts 8a and 8b that connect to the air conditioning units 3a and 3b on the occupancy side.

[0093] <Air conditioning unit on the heat source side>

[0095] The heat source-side air conditioning unit 2, as described above, is connected to the use-side air conditioning units 3a, 3b via refrigerant interconnection pipes 11, 12, forming part of the refrigerant circuit 10.

[0097] The heat source-side air conditioning unit 2 mainly comprises a compressor 21, a switching mechanism 23 and a heat source-side heat exchanger 24.

[0099] Compressor 21 is a mechanism for compressing the refrigerant, and in this embodiment, a sealed compressor is used in which a rotary, spiral or other type positive displacement compression element (not shown) housed in a casing (not shown) is driven by a compressor motor 22 also housed in the casing.

[0101] The switching mechanism 23 is a four-way switching valve capable of switching between an air-cooling operating state in which the heat source-side heat exchanger 24 functions as a refrigerant heat radiator, and an air-heating operating state in which the heat source-side heat exchanger 24 functions as a refrigerant evaporator. In this embodiment, the air-cooling operating state is a switched state in which communication is permitted between a discharge side of compressor 21 and a gas side of the heat source-side heat exchanger 24, and communication is permitted between the refrigerant gas interconnecting pipe 12 and an inlet side of compressor 21 (refer to the solid lines of the switching mechanism 23 in FIG. 1). The air heating operating state is a switched state in which communication is permitted between the discharge side of compressor 21 and the gaseous refrigerant interconnecting pipe 12, and communication is permitted between the gas side of the heat exchanger 24 on the heat source side and the intake side of compressor 21 (refer to the dashed lines of the switching mechanism 23 in FIG. 1). The switching mechanism 23 is not limited to a four-way switching valve. For example, the switching mechanism 23 can be configured to have a function for changing the direction of refrigerant flow, similar to that described above, by a technique such as combining multiple solenoid valves.

[0103] The heat source-side heat exchanger 24 functions as a heat radiator or refrigerant evaporator by performing heat exchange between the refrigerant and the outside air (OA). The outside air (OA), which exchanges heat with the refrigerant in the heat source-side heat exchanger 24, is supplied to the heat source-side heat exchanger 24 by a heat source-side fan 25 driven by a heat source-side fan motor 26.

[0105] <Air conditioning equipment on the use side>

[0107] The load-side air conditioning units 3a and 3b, as described above, are connected to the heat source-side air conditioning unit 2 via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. Furthermore, the load-side air conditioning units 3a and 3b, as described above, are designed to exchange air with the air-conditioned spaces S1 and S2 and/or the outside of the air-conditioned spaces S1 and S2 via air ducts 5 (5a, 5b), 6a, 6b, 7a, 7b, and 8 (8a, 8b). In the following description, the configuration of the air conditioning unit 3a on the use side is described, and the description of the configuration of the air conditioning unit 3b on the use side is omitted, replacing the additional letter “a” with “b” for each component.

[0109] The air conditioning apparatus 3a on the use side mainly comprises a housing 31a, a use-side expansion mechanism 32a, a use-side heat exchanger 33a, a total heat exchanger 34a, a first air supply turbine 35a, a first air exhaust turbine 37a, and a refrigerant leak detection device 48a.

[0111] The housing 31a is installed in the installation space on the use side S3, and several ducts 5a, 6a, 7a, 8a are connected to the housing 31a. A space is formed in the housing 31a to accommodate the use-side heat exchanger 33a and the like.

[0113] The load-side expansion mechanism 32a is an electrically operated expansion valve that can vary, by controlling the degree of opening, the flow rate of the refrigerant flowing through the load-side heat exchanger 33a. The load-side expansion mechanism 32a is provided within the housing 31a. One end of the load-side expansion mechanism 32a is connected to a liquid side of the load-side heat exchanger 33a, and the other end of the load-side expansion mechanism 32a is connected to the liquid refrigerant interconnecting tube 11 via a joint 13a. The joint 13a is a tube joint for connecting the load-side heat exchanger 33a to the refrigerant interconnecting tubes 11 and 12 and, in this embodiment, is provided within the housing 31a.

[0115] The load-side heat exchanger 33a is a heat exchanger for cooling or heating air (RA and/or OA) in the housing 31a by means of refrigerant supplied from the heat source-side air handling unit 2. The load-side heat exchanger 33a is provided within the housing 31a. The load-side heat exchanger 33a is connected to the heat source-side air handling unit 2 via refrigerant interconnecting pipes 11 and 12. One liquid side of the load-side heat exchanger 33a is connected to the liquid refrigerant interconnecting pipe 11 via the load-side expansion mechanism 32a and gasket 13a, and one gas side of the load-side heat exchanger 33a is connected to the refrigerant gas interconnecting pipe 12 via gasket 14a. Joint 14a is a tube joint for connecting the use-side heat exchanger 33a to the refrigerant gas interconnecting tube 12 and, in this embodiment, is provided inside the housing 31a.

[0116] The total heat exchanger 34a carries out the heat exchange between the outside air (OA) and the ambient air (RA). In this embodiment, a heat exchanger 34a is used that causes sensible and latent heat to be exchanged simultaneously between the two types of air (OA and RA). The total heat exchanger 34a is provided within the housing 31a, and the space within the housing 31a is divided by the total heat exchanger 34a into an air supply passage 42a and an air outlet passage 43a on the side closest to the air-conditioned space S1, and an air intake passage 41a and an air exhaust passage 44a on the side furthest from the air-conditioned space S1. The intake passage 41a communicates with the inlet duct 5 (5a), the supply air passage 42a communicates with the supply air duct 6a, the outlet passage 43a communicates with the outlet duct 7a, and the exhaust air passage 44a communicates with the exhaust air duct 8 (8a). The load-side expansion mechanism 32a and the load-side heat exchanger 33a are provided within the supply air duct 42a, inside the space within the housing 31a. In this embodiment, gaskets 13a and 14a are also provided within the supply air duct 42a. Therefore, the load-side heat exchanger 33a is designed to cool or heat the air within the supply air duct 42a. Furthermore, housing 31a is provided with an air return regulating mechanism 45a consisting of a communication passage that allows communication between the air supply passage 42a and the outlet passage 43a, and an air draft regulator located in this communication passage. The air return regulating mechanism 45a is capable of switching between an air supply and outlet communication state, which allows the outlet passage 43a to communicate with the air supply passage 42a by opening the air draft regulator, and a non-communication state for the air supply and outlet, which prevents the outlet passage 43a from communicating with the air supply passage 42a by closing the air draft regulator.

[0117] The first supply air turbine 35a is a fan provided to draw outside air (OA) from outside the air-conditioned space S1 and supply supply air (SA) to the air-conditioned space S1. The first supply air turbine 35a is provided within the supply air passage 42a, and an outlet of this turbine is connected to the supply air duct 6a. The first supply air turbine 35a is designed to be driven by a first supply air turbine motor 36a.

[0119] The first exhaust turbine 37a is a fan provided to draw ambient air (RA) from the air-conditioned space S1 and expel exhaust air (EA) from the air-conditioned space S1. The first exhaust turbine 37a is provided within the exhaust air passage 44a, and an outlet of this turbine is connected to the exhaust air duct 8 (8a). The first exhaust turbine 37a is designed to be driven by a first exhaust turbine motor 38a. In addition, a backflow prevention mechanism 46a, consisting of an air draft regulator, is provided at the outlet of the first exhaust turbine 37a. The air draft regulator of the backdraft prevention mechanism 46a is designed to open to expel exhaust air (EA) into exhaust duct 8 when the first exhaust turbine 37a is operating, and to close to prevent backdraft of exhaust air (EA) from exhaust duct 8 when the first exhaust turbine 37a has stopped operating. The backdraft prevention mechanism 46a may be provided in exhaust duct 8a instead of at the outlet of the first exhaust turbine 37a. The backdraft prevention mechanism 46a may not be provided when backdraft of exhaust air (EA) is guaranteed, such as when a turbine is provided in exhaust duct 8.

[0121] When the air ducts 41a, 42a, 43a, 44a, the mechanisms 45a, 46a and the turbines 35a, 37a described above are connected to the air ducts 5 (5a), 6a, 6b, 7a, 7b, 8 (8a), there is configured an air supply/extraction mechanism of the air conditioning unit 3a on the use side, which brings ambient air (RA) into the interior of housing 31a from the air-conditioned space S1, brings outside air (OA) into the interior of housing 31a from outside the air-conditioned space S1, supplies the air in housing 31a as supply air (SA) to the air-conditioned space S1, and expels the air in housing 31a as exhaust air (EA) from the air-conditioned space S1.

[0123] The refrigerant leak detection device 48a is a device for detecting refrigerant. The refrigerant leak detection device 48a is provided within the housing 31a. In this embodiment, the refrigerant leak detection device 48a is provided within the air supply duct 42a in which the load-side heat exchanger 33a is located (in this embodiment, the gaskets 13a, 14a and/or the load-side expansion mechanism 32a). Furthermore, in this embodiment, the refrigerant leak detection device 48a is provided in a lower portion (when the refrigerant is denser than air) of the housing 31a (in this embodiment, the air supply passage 42a) or in an upper portion (when the refrigerant is less dense than air) of the housing 31a (in this embodiment, the air supply passage 42a). FIG. Figure 1 shows a case in which the refrigerant leak detection device 48a is provided at the bottom of housing 31a.

[0125] <Control Device>

[0127] Air conditioning unit 1 has a control device 9 to perform operational control in air conditioning unit 2 on the heat source side and air conditioning units 3a, 3b on the use side, etc. Control device 9 mainly has a heat source-side control device 92 to control the actions of the components (compressor, etc.) configuring air conditioning unit 2 on the heat source side, and use-side control devices 93a, 93b to control the actions of the components (fans, refrigerant leak detection devices, etc.) configuring air conditioning units 3a, 3b on the use side. The heat source-side control device 92, with which the heat source-side air conditioning unit 2 is equipped, has a microcomputer and/or memory, etc., for controlling the heat source-side air conditioning unit 2. The load-side control devices 93a and 93b, with which the load-side air conditioning units 3a and 3b are equipped, have microcomputers and/or memory, etc., for controlling the load-side air conditioning units 3a and 3b. The heat source-side control device 92 and the load-side control devices 93a and 93b are connected to allow the exchange of, for example, control signals via a transmission line, and the control device 9 of the air conditioning unit 1 is configured accordingly. In this embodiment, the control devices 92, 93a, 93b are connected via a transmission line, but they are not limited to being connected in this way and can be connected wirelessly or by another connection method.

[0129] (2) Operations

[0131] The following operations are performed on air conditioning unit 1, which has the configuration described above. The operating controls of air conditioning unit 1, described below, are performed by control device 9.

[0133] <Normal operation>

[0135] Under normal operation, an operation is carried out such that outside air (OA) is introduced into housings 31a, 31b from outside the air-conditioned spaces S1, S2, the air is cooled or heated in the use-side heat exchangers 33a, 33b and then supplied as supply air (SA) to the air-conditioned spaces S1, S2; ambient air (RA) is brought into housings 31a, 31b from the air-conditioned spaces S1, S2, the air exchanges heat with the outside air (OA) in the total heat exchangers 34a, 34b, and then the air is expelled as exhaust air (EA) outside the air-conditioned spaces S1, S2, as shown in FIG. 1. Specifically, in the components of air conditioning unit 1, an operational check is carried out as follows.

[0137] When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being cooled in the use-side heat exchangers 33a, 33b in the heat source-side air conditioning unit 2, the switching mechanism 23 is switched to the air-cooling operating state (the state shown by the solid lines of the switching mechanism 23 in FIG.

[0138] 1), and the compressor 21 and the fan 25 on the heat source side are activated. The high-pressure gaseous refrigerant discharged from the compressor 21 is thus sent through the switching mechanism 23 to the heat exchanger 24 on the heat source side, which functions as a refrigerant heat radiator. The high-pressure refrigerant gas sent to the heat exchanger 24 on the heat source side condenses into high-pressure liquid refrigerant as it is cooled by heat exchange with the outside air (OA) supplied by the heat source-side fan 25 in the heat exchanger 24. This high-pressure liquid refrigerant is then sent to the air conditioning units 3a and 3b on the load side via the liquid refrigerant interconnecting pipe 11. The high-pressure liquid refrigerant supplied to the load-side air conditioning units 3a and 3b is decompressed into a low-pressure, two-phase gas-liquid refrigerant by the load-side expansion mechanisms 32a and 32b. This low-pressure, two-phase gas-liquid refrigerant is then supplied to the load-side heat exchangers 33a and 33b, which function as refrigerant evaporators. The low-pressure, two-phase gas-liquid refrigerant supplied to the load-side heat exchangers 33a and 33b evaporates in these heat exchangers, becoming a low-pressure refrigerant gas due to heat exchange with the air within the air supply ducts 42a and 42b. This low-pressure refrigerant gas is then supplied to the heat source-side air conditioning unit 2 via the refrigerant interconnecting pipe 12. The low-pressure refrigerant gas sent to the air conditioning unit 2 on the heat source side is introduced into the compressor 21 through the switching mechanism 23.

[0140] When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being heated in the load-side heat exchangers 33a, 33b in the heat-source-side air conditioning unit 2, the switching mechanism 23 is switched to the air heating operating state (the state shown by the dashed lines of the switching mechanism 23 in FIG. 1), and the heat-source-side compressor 21 and fan 25 are activated. The high-pressure gaseous refrigerant discharged from the compressor 21 is thus delivered to the load-side air conditioning units 3a, 3b via the switching mechanism 23 and the gaseous refrigerant interconnecting pipe 12. The high-pressure gaseous refrigerant supplied to the load-side air conditioning units 3a and 3b is directed to the load-side heat exchangers 33a and 33b, which function as refrigerant heat radiators. The high-pressure refrigerant gas supplied to the load-side heat exchangers 33a and 33b condenses within these units, resulting in high-pressure liquid refrigerant. This condensing occurs as it cools through heat exchange with the air within the air supply ducts 42a and 42b. This high-pressure liquid refrigerant is then decompressed by the load-side expansion mechanisms 32a and 32b. The decompressed refrigerant is then supplied to the heat source-side air conditioning unit 2 via the liquid refrigerant interconnecting pipe 11. The refrigerant supplied to the air conditioning unit 2 on the heat source side is sent to the heat exchanger 24 on the heat source side, which functions as a refrigerant evaporator. The refrigerant in the heat exchanger 24 evaporates, producing low-pressure refrigerant gas because it is heated by heat exchange with the outside air (OA) supplied by the fan 25 on the heat source side. This low-pressure refrigerant gas is then introduced into the compressor 21 via the switching mechanism 23.

[0142] At this moment, in the air conditioning units 3a, 3b on the use side, the backflow prevention mechanisms 46a, 46b open and the first supply air turbines 35a, 35b and the first exhaust air turbines 37a, 37b are activated. This causes outside air (OA) to be drawn through the intake duct 5 (5a, 5b) into the intake ducts 41a, 41b of the housings 31a, 31b from outside the air-conditioned spaces S1, S2, and ambient air (RA) to be drawn through the outlet ducts 7a, 7b into the outlet passages 43a, 43b of the housings 31a, 31b from the air-conditioned spaces S1, S2. Outside air (OA) and ambient air (RA) introduced into housings 31a and 31b are made to exchange heat in the total heat exchangers 34a and 34b, and are then sent to the supply air duct 42a and the exhaust air duct 44a, respectively. In this embodiment, when the return air regulating mechanisms 45a and 45b are switched to the outlet air supply communication state (refer to the return air regulating mechanisms 45a and 45b in FIG. 1), part of the ambient air (RA) introduced into housings 31a and 31b is sent to the supply air passage 42a according to the opening degrees of the air draft regulators of the return air regulating mechanisms 45a and 45b, and this air merges with the outside air (OA) that has undergone heat exchange in the total heat exchangers 34a and 34b. When the return air regulating mechanisms 45a, 45b are switched to the non-communicative air supply-exit state, all the ambient air (RA) entering the housings 31a, 31b undergoes heat exchange with all the outside air (OA) introduced into the housings 31a, 31b. The ambient air (RA) sent to the exhaust air steps 44a, 44b is expelled as exhaust air (EA) from the air-conditioned spaces S1, S2 through the first exhaust air turbines 37a, 37b and the exhaust air duct 8 (8a, 8b). The outside air (OA) or outside air (OA) including ambient air (RA), supplied to the air supply ducts 42a, 42b, is cooled or heated in the load-side heat exchangers 33a, 33b by the refrigerant supplied by the heat source-side air conditioning unit 2 through the liquid refrigerant interconnecting pipe 11. The cooled or heated outside air (OA) or outside air (OA) including ambient air (RA), supplied in the load-side heat exchangers 33a, 33b, is delivered as supply air (SA) to the air-conditioned spaces S1, S2 through the first air supply turbines 35a, 35b and the air supply ducts 6a, 6b.

[0144] <Refrigerant expulsion operation>

[0146] During the normal operation described above, when refrigerant leaks occur in the air conditioning units 3a and 3b on the load side, the leaking refrigerant is supplied to the air-conditioned spaces S1 and S2, posing a risk of ignition accidents (when the refrigerant is flammable or slightly flammable) or poisoning accidents (when the refrigerant is toxic). Therefore, when the refrigerant leak detection devices 48a and 48b detect refrigerant, a refrigerant expulsion operation is performed to expel the refrigerant, along with air, from the housings 31a and 31b outside the air-conditioned spaces S1 and S2, using the air supply/extraction mechanisms. In this embodiment, the refrigerant expulsion operation is performed by actuating the first air extraction turbines 37a and 37b, thus configuring the air supply/extraction mechanisms.

[0148] For example, assuming that a refrigerant leak has occurred in the use-side air conditioning unit 3b (i.e., the refrigerant leak detection device 48b has detected refrigerant), the first exhaust turbine 37b in the use-side air conditioning unit 3b shown in FIG. 3 is operated. The leaking refrigerant, together with the air in the housing 31b, thus passes through the section of the total heat exchanger 34b that communicates with the outlet passage 43b and the exhaust passage 44b, and is discharged to the exhaust air duct 8 (8b). At this time, because the load-side heat exchanger 33b and gaskets 13b and 14b, which have a high potential for refrigerant leakage, are located in the supply air duct 42b, the supply air duct 42b and the outlet air duct 43b are allowed to communicate. This facilitates the expulsion of refrigerant by placing the return air regulating mechanism 45b in the supply-outlet communication state. The first supply air turbine 35b is stopped to prevent leaking refrigerant from being supplied to the air-conditioned space S2. In this embodiment, when the first air supply turbine 35b is stopped and the first air extraction turbine 37b is operated, ambient air (RA) is drawn into housing 31b from the air-conditioned space S2, and outside air (OA) is drawn into housing 31b from outside the air-conditioned space S2. These two types of air (RA and OA) are therefore discharged to the air extraction duct 8 (8b) along with the leaking refrigerant. In the heat source-side air conditioning unit 2, refrigerant is prevented from being supplied from the heat source-side air conditioning unit 2 to the load-side air conditioning unit 3b, for example, because the compressor 21 is stopped. In the air conditioning unit 3a on the use side, where there is no refrigerant leakage, the refrigerant leaking from the air conditioning unit 3b on the use side is prevented from flowing back into the housing 31a through the air extraction duct 8 (8a) by closing the backflow prevention mechanism 46a.

[0150] (3) Features

[0152] The air conditioning appliances 3a, 3b on the use side of the present embodiment and the air conditioning appliance 1 provided with them have characteristics such as the following.

[0154] <A>

[0156] In this embodiment, as described above, in the air conditioning units 3a and 3b on the load side, which have the ventilation air conditioning function, and in air conditioning unit 1 provided with the same, when the refrigerant leak detection devices 48a and 48b detect refrigerant, the refrigerant expulsion operation is carried out by means of the air supply/extraction mechanisms to expel the refrigerant, along with the air, from the air-conditioned spaces S1 and S2, from the housings 31a and 31b. Specifically, in this embodiment, the refrigerant expulsion operation is carried out by actuating the first air extraction turbines 37a and 37b. Furthermore, in this embodiment, air conditioning unit 1 is configured by connecting the heat source-side air conditioning unit 2 and the plurality (two in this embodiment) of air conditioning units 3a and 3b on the load side.

[0158] In this embodiment, when a refrigerant leak occurs, it is possible to ensure that the leaking refrigerant is quickly expelled and not supplied to the air-conditioned spaces S1 and S2 by using the air supply/extraction mechanisms (in this embodiment, by operating the first air extraction turbines 37a and 37b). Furthermore, in this embodiment, when a refrigerant leak occurs in any of the plurality of air-conditioning units 3a and 3b on the load side, it is possible to ensure that the leaking refrigerant is quickly extracted using the supply/extraction mechanism of the air-conditioning unit 3a or 3b on the load side from which the leak occurred, and that the refrigerant is not supplied to the air-conditioned space S1 or S2 being conditioned by the air-conditioning unit 3a or 3b on the load side from which the leak occurred.

[0160] When the refrigerant is flammable or slightly flammable, ignition accidents in air-conditioned spaces S1, S2 can be suppressed. When the refrigerant is toxic, poisoning accidents in air-conditioned spaces S1, S2 can be suppressed. The incidence of oxygen deficiency accidents in air-conditioned spaces S1, S2 can be suppressed even when the refrigerant is non-flammable, slightly flammable, or toxic.

[0162] <B>

[0164] In this embodiment, as described above, gaskets 13a, 13b, 14a, and 14b are provided within housings 31a and 31b, connecting the load-side heat exchangers 33a and 33b to the refrigerant interconnecting tubes 11 and 12. Therefore, when refrigerant leaks from gaskets 13a, 13b, 14a, and 14b connecting the load-side heat exchangers 33a and 33b to the refrigerant interconnecting tubes 11 and 12, the leak is within housings 31a and 31b.

[0166] Therefore, in this embodiment it is possible to quickly detect the refrigerant when a leak has occurred, and to quickly expel the leaked refrigerant.

[0168] <C>

[0170] In this embodiment, as described above, when the refrigerant is denser than air, the refrigerant leak detection devices 48a, 48b are provided in the lower parts of the housings 31a, 31b.

[0172] Therefore, in this embodiment it is possible to quickly detect the refrigerant using the tendency of the refrigerant, which is denser than air, to accumulate downwards.

[0174] In this embodiment, as described above, when the refrigerant is less dense than air, the refrigerant leak detection devices 48a, 48b are provided on the upper parts of the housings 31a, 31b.

[0176] Therefore, in this embodiment it is possible to quickly detect the refrigerant using the tendency of the refrigerant, which is less dense than air, to accumulate upwards.

[0178] (4) Modifications that are not part of the invention

[0180] In the above described use-side air conditioning units 3a, 3b and air conditioning unit 1 provided with the same (see FIGS. 1 to 3), the gaskets 13a, 13b, 14a, 14b connecting the use-side heat exchangers 33a, 33b to the refrigerant interconnecting pipes are provided inside the housings 31a, 31b. But in examples not part of the invention, there are also cases where the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b, as shown in FIG. 4. In these cases, when there are refrigerant leaks from joints 13a, 13b, 14a, 14b, the leak occurs in the installation spaces on the use side S3, S4 where the housings 31a, 31b of the use-side air conditioning appliances 3a, 3b are installed.

[0182] In view of this, in this modification, the air handling units 3a, 3b on the use side are provided with indoor-outdoor communication mechanisms 47a, 47b, which are capable of switching between an indoor-outdoor communication state to allow communication between the installation spaces S3, S4 on the use side and the interiors of the housings 31a, 31b, and an indoor-outdoor non-communication state which does not allow communication between the installation spaces S3, S4 on the use side and the interiors of the housings 31a, 31b, as shown in FIGS. 4 and 5, and the refrigerant expulsion operation is carried out by putting the indoor-outdoor communication mechanisms 47a, 47b into the indoor-outdoor communication state.

[0184] The following is a description, using FIGS. 2, 4 and 5, of the configurations and operations of the use-side air conditioning units 3a, 3b in accordance with the present amendment and of air conditioning unit 1 provided with them, focusing on the differences with the use-side air conditioning units 3a, 3b described above and air conditioning unit 1 provided with them (see FIGS. 1 to 3).

[0185] First, the configurations of the air handling units 3a and 3b on the use side, and of air handling unit 1 provided with them, are described in accordance with this amendment. In this amendment, the general configuration of air handling unit 1 and the configuration of air handling unit 2 on the heat source side, as described herein, are similar to the configuration of air handling unit 1 (see FIG. 1) and the configuration of air handling unit 2 on the heat source side (see FIG. 1) described above and are therefore not described here.

[0187] The configurations of the use-side air conditioning units 3a, 3b according to the present amendment differ from the configurations of the use-side air conditioning units 3a, 3b described above (see FIG. 1) because the gaskets 13a, 13b, 14a, 14b connecting the use-side heat exchangers 33a, 33b to the refrigerant interconnecting pipes are provided outside the housings 31a, 31b, as shown in FIG. 4. The housings 31a, 31b are also provided with the indoor-outdoor communication mechanisms 47a, 47b as described above. The indoor-outdoor communication mechanisms 47a and 47b consist of communication passages to enable communication between the air supply passages 42a and 42b and the installation spaces on the use side, S3 and S4, and the air draft regulators located in these communication passages. The indoor-outdoor communication mechanisms 47a and 47b are capable of switching between an indoor-outdoor communication state, allowing the air supply passages 42a and 42b and the installation spaces on the use side, S3 and S4, to communicate by opening the air draft regulators, and a non-indoor-outdoor communication state, preventing the air supply passages 42a and 42b and the installation spaces on the use side, S3 and S4, from communicating. Also provided on the exterior of housings 31a, 31b are refrigerant leak detection devices 49a, 49b to detect refrigerant that has leaked into the installation spaces on the use side S3, S4. Also provided to the installation spaces on the use side S3, S4 are interior-to-exterior communication mechanisms 39a, 39b consisting of communication passages that connect to the exterior of the installation spaces on the use side S3, S4 and air draft regulators located in these communication passages. The mechanisms 39a, 39b for interior-exterior communication of the installation space are capable of switching between an interior-exterior communication state of the installation space to allow the installation spaces on the use side S3, S4 and their exteriors to communicate by opening the air draft regulators and a non-interior-exterior communication state of the installation space to prevent the installation spaces on the use side S3, S4 and their exteriors from communicating by closing the air draft regulators. The indoor-outdoor communication mechanisms 47a and 47b, and the installation space for the indoor-outdoor communication mechanisms 39a and 39b, together with the air passages 41a, 42a, 43a, and 44a, the mechanisms 45a and 46a, and the air turbines 35a and 37a, constitute the air supply/extraction mechanisms for the air handling units 3a and 3b on the user side, in accordance with this amendment. The configurations of the air handling units 3a and 3b on the user side, in accordance with this amendment, are otherwise similar to the configurations of the air handling units 3a and 3b on the user side described above (see FIG.

[0188] 1) and therefore are not described here.

[0190] The configuration of a control device 9 according to the present amendment is similar to the configuration of the control device 9 described above (see FIG. 2), except for the feature that the operational control is carried out on the newly provided indoor-outdoor communication mechanisms 47a, 47b, on the refrigerant leak detection devices 49a, 49b, and on the indoor-outdoor communication mechanisms 39a, 39b of the installation space and is therefore not illustrated or described herein.

[0192] The operation of the load-side air conditioning units 3a and 3b, as amended herein, and of air conditioning unit 1 provided with them, is described below. In this amendment, the operation of the heat source-side air conditioning unit 2 of air conditioning unit 1, as amended herein, is similar to the operation of the heat source-side air conditioning unit 2 of air conditioning unit 1 described above and is therefore not described herein.

[0193] During normal operation, the operation of the use-side air conditioning appliances 3a, 3b in accordance with the present amendment involves putting the indoor-outdoor communication mechanisms 47a, 47b in the non-indoor-outdoor communication state and the indoor-outdoor communication mechanisms 39a, 39b of the installation space in the non-indoor-outdoor communication state of the installation space as shown in FIG. 4, and the resulting operation is substantially similar to the normal operation of the use-side air conditioning appliances 3a, 3b described above (see FIG. 1).

[0194] However, the refrigerant expulsion operation of the use-side air conditioning appliances 3a, 3b according to the present amendment differs from the refrigerant expulsion operation of the use-side air conditioning appliances 3a, 3b described above (see FIG. 3), because the indoor-outdoor communication mechanisms 47a, 47b are put into the indoor-outdoor communication state, as described above.

[0196] For example, assuming that a refrigerant leak has occurred in the air handling unit 3b on the use side (specifically, that the refrigerant leak detection devices 48b, 49b have detected refrigerant), in the air handling unit 3b on the use side, the indoor-outdoor communication mechanism 47b is put into the indoor-outdoor communication state and the first exhaust turbine 37b is operated, as shown in FIG. 5. The leaked refrigerant, together with the air in the housing 31b, thus passes through the section of the total heat exchanger 34b that communicates with the outlet passage 43b and the exhaust passage 44b, and is discharged to the exhaust duct 8 (8b). At this time, because the gaskets 13b, 14b, which have a high possibility of refrigerant leakage, are located outside the housing 31b (the installation space on the S4 use side), refrigerant sometimes leaks into the installation space on the S4 use side. However, because the air supply passage 42b of the housing 31b and the installation space on the S4 use side can communicate by placing the inside-outside communication mechanism 47b in the inside-outside communication state as described above, the refrigerant leaking into the installation space on the S4 use side is guided into the inside of the housing 31b using the inside-outside communication mechanism 47b. Along with the air in the housing 31b, the refrigerant passes through the section of the total heat exchanger 34b that communicates with the outlet passage 43b and the exhaust air passage 44b and is expelled into the exhaust air duct 8 (8b). Furthermore, the indoor-outdoor communication mechanisms 39a and 39b of the installation space are placed in the indoor-outdoor communication state, facilitating the routing of air from the installation space on the S4 use side to the air supply duct 42b. Other operational actions in the refrigerant expulsion operation according to this amendment are similar to those of the refrigerant expulsion operation in the air conditioning units 3a and 3b on the use side described above (see FIG. 3) and are therefore not described here.

[0198] In such use-side air conditioning appliances 3a, 3b in accordance with the present amendment and air conditioning appliance 1 provided therewith, because the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b, the effects derived from providing the gaskets 13a, 13b, 14a, 14b inside the housings 31a, 31b cannot be achieved, but, in other respects, the same operating effects can be achieved as those of the use-side air conditioning appliances 3a, 3b described above and in the air conditioning appliance 1 provided therewith (see FIGS. 1 to 3).

[0200] Furthermore, in this modification, communication between the use-side installation spaces S3, S4 and the interior of the housing can be permitted by the inside-outside communication mechanisms 47a, 47b, regardless of whether the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b. Therefore, in this modification, when a refrigerant leak has occurred, the refrigerant that has leaked into the use-side installation spaces S3, S4 can be quickly expelled while being directed towards the housings 31a, 31b and can be prevented from being supplied to the air-conditioned spaces S1, S2, by using the air supply/extraction mechanisms that include the inside-outside communication mechanisms 47a, 47b.

[0202] -Second realization-

[0203] (1) Configuration

[0205] FIG. 6 is a general configuration diagram of an air conditioning unit with air conditioning units 3a, 3b on the use side according to a second embodiment of the present invention. FIG. 7 is a control block diagram of air conditioning unit 1 of the second embodiment.

[0207] <Overview>

[0209] Air conditioning appliance 1, which is an air conditioning ventilation system having an air conditioning function to ventilate and condition the interior of a room, mainly has an air conditioning appliance 2 on the heat source side, and a plurality (two in this embodiment) of air conditioning appliances 3a, 3b on the use side.

[0211] Air conditioning unit 1 has a refrigerant circuit 10 through which refrigerant circulates. The refrigerant circuit 10 is configured by connecting the heat source-side air conditioning unit 2 to the load-side air conditioning units 3a and 3b. In this embodiment, the heat source-side air conditioning unit 2 is installed in a location such as the roof of a building, and the load-side air conditioning units 3a and 3b are installed in load-side installation spaces (in this embodiment, load-side installation spaces S3 and S4), such as a building machine room or a space above the roof, corresponding to air-conditioned spaces (in this embodiment, air-conditioned spaces S1 and S2) that are ventilated and conditioned. The heat source-side air conditioning unit 2 and the user-side air conditioning units 3a and 3b are connected via refrigerant interconnecting pipes 11 and 12, thus forming refrigerant circuit 10. The refrigerant sealed within refrigerant circuit 10 is either a mildly flammable refrigerant such as R32, a flammable refrigerant such as propane, or a toxic refrigerant such as ammonia.

[0213] Air conditioning unit 1 has a plurality of air ducts. In this embodiment, air conditioning unit 1 has an intake duct 5 for carrying outside air (OA) into the use-side air conditioning units 3a, 3b from outside the air-conditioned spaces S1, S2, supply air ducts 6a, 6b for supplying supply air (SA) from the use-side air conditioning units 3a, 3b to the air-conditioned spaces S1, S2, and outlet ducts 7a, 7b for taking ambient air (RA) from the air-conditioned spaces S1, S2 into the corresponding use-side air conditioning units 3a, 3b, so that air can be exchanged between the air-conditioned spaces S1, S2 and/or the outside of the air-conditioned spaces S1, S2 and the use-side air conditioning units 3a, 3b. Also connected to the air-conditioned spaces S1, S2 is an exhaust air duct 8 to expel exhaust air (EA) from the air-conditioned spaces S1, S2. The intake duct 5 has intake branch ducts 5a, 5b which branch off to correspond to the air conditioning units 3a, 3b on the use side, and the exhaust air duct 8 has exhaust air branch ducts 8a, 8b which branch off to correspond to the air-conditioned spaces S1, S2.

[0215] <Air conditioning unit on the heat source side>

[0217] The heat source-side air conditioning unit 2, as described above, is connected to the load-side air conditioning units 3a and 3b via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. The configuration of the heat source-side air conditioning unit 2 according to the present embodiment is similar to the configuration of the heat source-side air conditioning unit 2 of the first embodiment described above (see FIG.

[0218] 1) and therefore is not described here.

[0220] <Air conditioning equipment on the use side>

[0222] The load-side air conditioning units 3a and 3b, as described above, are connected to the heat source-side air conditioning unit 2 via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. Furthermore, the load-side air conditioning units 3a and 3b, as described above, are designed to exchange air with the air-conditioned spaces S1 and S2 and/or the outside of the air-conditioned spaces S1 and S2 via air ducts 5 (5a, 5b), 6a, 6b, 7a, and 7b. In the following description, the configuration of the load-side air conditioning unit 3a is described, while the description of the configuration of the load-side air conditioning unit 3b is omitted, with the additional letter “a” being replaced by “b” for each component.

[0224] The use-side air conditioning apparatus 3a mainly comprises a housing 31a, a use-side expansion mechanism 32a, a use-side heat exchanger 33a, an air supply/extraction turbine 51a, and a refrigerant leak detection device 48a.

[0226] The housing 31a is installed in the use-side installation space S3, and several ducts 5a, 6a, 7a are connected to the housing 31a. An air supply passage 42a is formed in the housing 31a to accommodate the use-side heat exchanger 33a and the like.

[0228] The load-side expansion mechanism 32a is an electrically adjustable expansion valve that controls the degree of opening and the flow rate of refrigerant through the load-side heat exchanger 33a. The load-side expansion mechanism 32a is provided within the housing 31a (within the air supply passage 42a in this embodiment). One end of the load-side expansion mechanism 32a is connected to a liquid side of the load-side expansion mechanism 32a, and the other end is connected to the liquid refrigerant interconnecting pipe 11 via a joint 13a. The joint 13a is a pipe joint for connecting the load-side heat exchanger 33a to the refrigerant interconnecting pipes 11 and 12 and, in this embodiment, is provided within the housing 31a (within the air supply passage 42a in this embodiment).

[0230] The load-side heat exchanger 33a is a heat exchanger for cooling or heating the air (RA and/or OA) in the housing 31a by means of the refrigerant supplied from the heat source-side air conditioning unit 2. A load-side heat exchanger 33a is provided within the housing 31a (within the air supply passage 42a in this embodiment). The load-side heat exchanger 33a is connected to the heat source-side air conditioning unit 2 via the refrigerant interconnecting pipes 11 and 12. One liquid side of the load-side heat exchanger 33a is connected to the liquid refrigerant interconnecting pipe 11 via the load-side expansion mechanism 32a and gasket 13a, and one gas side of the load-side heat exchanger 33a is connected to the refrigerant gas interconnecting pipe 12 via gasket 14a. Gasket 14a is a pipe joint for connecting the load-side heat exchanger 33a to the refrigerant gas interconnecting pipe 12 and, in this embodiment, is provided inside the housing 31a (inside the air supply passage 42a in this embodiment).

[0232] The supply/exhaust air turbine 51a is a fan provided to be able to switch between a supply air state of drawing ambient air (RA) from the air-conditioned space S1, drawing outside air (OA) from outside the air-conditioned space S1, and supplying supply air (SA) to the air-conditioned space S1, and an exhaust air state of extracting exhaust air (EA) from outside the air-conditioned space S1. The supply/exhaust air turbine 51a is provided within the supply air passage 42a, and an outlet of this turbine is connected to the supply air duct 6a. The supply/exhaust air turbine 51a is designed to be driven by a supply/exhaust air turbine motor 52a. An air supply prevention mechanism 54a, consisting of an air draft regulator, is provided at the outlet of the supply/exhaust air turbine 51a. The air draft regulator of the air supply prevention mechanism 54a opens when the air supply/extraction turbine 51a is operating in the air supply state and closes when the air supply/extraction turbine 51a is operating in the air extraction state. The air supply prevention mechanism 54a may be provided at the air supply duct 6a instead of at the outlet of the air supply/extraction turbine 51a. One end of a bypass passage 53a is connected to the outlet of the air supply/extraction turbine 51a at a position upstream of the air supply prevention mechanism 54a. The other end of the bypass passage 53a is connected to an outside air inlet (OA) in the housing 31a. A bypass opening/closing mechanism 55a, consisting of an air draft regulator, is provided in the bypass passage 53a. The air draft regulator of the bypass opening/closing mechanism 55a closes when the supply/exhaust air turbine 51a is operating in the supply air state, and opens when the supply/exhaust air turbine 51a is operating in the exhaust air state. The bypass passage 53a, which includes the bypass opening/closing mechanism 55a, instead of being connected between the outlet of the supply/exhaust air turbine 51a and the outside air inlet (OA) of the housing 31a, may be provided to be connected between the supply air duct 6a and the intake duct 5 (5a). An intake prevention mechanism 56a, consisting of an air draft regulator, is provided at the outside air inlet (OA) of the housing 31a in a position closer to the supply air passage 42a than to the position where the other end of the bypass passage 53a is connected. The air draft regulator of the intake prevention mechanism 56a opens when the supply/extraction air turbine 51a is operating in the supply air state and closes when the supply/extraction air turbine 51a is operating in the extraction air state. An air return regulating mechanism 57a, consisting of an air draft regulator, is provided at the outside air inlet (OA) of housing 31a. This mechanism is located closer to the inlet duct 5 (5a) than to the position where the other end of the bypass passage 53a is connected. The intake prevention mechanism 56a and the air return regulating mechanism 57a may be provided at the intake bypass duct 5a instead of at the outside air inlet (OA) of housing 31a. Therefore, the supply/extraction air turbine 51a can be switched between supply and extraction operation by means of bypass step 53a, supply air prevention mechanism 54a, bypass opening/closing mechanism 55a, and intake prevention mechanism 56a. Specifically, the supply/extraction air turbine 51a can be operated in supply mode by opening supply air prevention mechanism 54a and intake prevention mechanism 56a and closing bypass opening/closing mechanism 55a. Conversely, the supply/extraction air turbine 51a can be operated in extraction mode by closing supply air prevention mechanism 54a and intake prevention mechanism 56a and opening bypass opening/closing mechanism 55a.

[0234] The air ducts 42a, 53a, mechanisms 54a, 55a, 56a, 57a, and turbine 51a described above, when connected with air ducts 5 (5a), 6a, 6b, 7a, 7b, configure a use-side air supply/extraction mechanism of the air conditioning appliance 3a to bring ambient air (RA) into the interior of housing 31a from the air-conditioned space S1, bring outside air (OA) into the interior of housing 31a from the outside of the air-conditioned space S1, supply the air inside housing 31a as supply air (SA) to the air-conditioned space S1, and expel the air inside housing 31a as exhaust air (EA) outside of the air-conditioned space S1.

[0236] The refrigerant leak detection device 48a is a device for detecting refrigerant. The refrigerant leak detection device 48a is provided within the housing 31a. In this embodiment, the refrigerant leak detection device 48a is provided within the air supply duct 42a in which the service-side heat exchanger 33a is located (in this embodiment, the seals 13a, 14a and/or the service-side expansion mechanism 32a). Furthermore, in this embodiment, the refrigerant leak detection device 48a is provided in a lower portion (when the refrigerant is denser than air) of the housing 31a (in this embodiment, the air supply duct 42a) or in an upper portion (when the refrigerant is less dense than air) of the housing 31a (in this embodiment, the air supply passage 42a). FIG. Figure 6 shows a case in which the refrigerant leak detection device 48a is provided at the bottom of housing 31a.

[0238] <Control Device>

[0240] Air conditioning unit 1 has a control device 9 to perform operational control in air conditioning unit 2 on the heat source side and air conditioning units 3a, 3b on the use side, etc. Control device 9 mainly has a control device 92 on the heat source side to control the actions of the components (compressor, etc.) configuring air conditioning unit 2 on the heat source side, and control devices 93a, 93b on the use side to control the actions of the components (fans, refrigerant leak detection devices, etc.) configuring air conditioning units 3a, 3b on the use side. The heat source-side control device 92, with which the heat source-side air conditioning unit 2 is equipped, has a microcomputer and/or memory, etc., for controlling the heat source-side air conditioning unit 2. The load-side control devices 93a and 93b, with which the load-side air conditioning units 3a and 3b are equipped, have microcomputers and/or memory, etc., for controlling the load-side air conditioning units 3a and 3b. The heat source-side control device 92 and the load-side control devices 93a and 93b are connected to allow the exchange of, for example, control signals via a transmission line, and the control device 9 of the air conditioning unit 1 is configured accordingly. In this embodiment, the control devices 92, 93a, 93b are connected via a transmission line, but they are not limited to being connected in this way and can be connected wirelessly or by another connection method.

[0242] (2) Actions

[0244] The following operations are performed on air conditioning unit 1, which has the configuration described above. The operating controls of air conditioning unit 1, described below, are performed by control device 9.

[0246] <Normal operation>

[0248] In normal operation, an operation is performed such that outside air (OA) is introduced into housings 31a, 31b from outside the air-conditioned spaces S1, S2, ambient air (RA) is introduced into housings 31a, 31b from the air-conditioned spaces S1, S2, and the air is cooled or heated in the use-side heat exchangers 33a, 33b and then supplied as supply air (SA) to the air-conditioned spaces S1, S2, as shown in FIG. 6. In this embodiment, exhaust air (EA) exits the air-conditioned spaces S1, S2 through the exhaust air duct 8 (8a, 8b) connected to the air-conditioned spaces S1, S2. Specifically, an operational check as follows is performed on the components of air conditioning unit 1.

[0250] When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being cooled in the use-side heat exchangers 33a, 33b in the heat source-side air conditioning unit 2, the switching mechanism 23 is switched to the air-cooling operating state (the state shown by the solid lines of the switching mechanism 23 in FIG.

[0251] 6), and the compressor 21 and the fan 25 on the heat source side are actuated. When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being heated in the use-side heat exchangers 33a, 33b in the air conditioning unit 2 on the heat source side, the switching mechanism 23 is switched to the air heating operating state (the state shown by the dashed lines of the switching mechanism 23 in FIG. 6), and the compressor 21 and the fan 25 on the heat source side are actuated. In this embodiment, the actions of the refrigerant circuit components 10, etc., are the same as the actions of the refrigerant circuit components 10, etc., of the first embodiment and are therefore not described here.

[0253] In the air handling units 3a and 3b on the use side, the air supply prevention mechanisms 54a and 54b, the intake prevention mechanisms 56a and 56b, and the return air regulation mechanisms 57a and 57b are open, the bypass opening/closing mechanism 55a is closed, and the supply/extraction air turbines 51a and 51b are operating. Specifically, the supply/extraction air turbines 51a and 51b are operating in the supply air state. Due to these actions, outside air (OA) is introduced into the air supply ducts 42a, 42b of the housings 31a, 31b from outside the air-conditioned spaces S1, S2 through the inlet duct 5 (5a, 5b), and ambient air (RA) is introduced into the air supply ducts 42a, 42b of the housings 31a, 31b from the air-conditioned spaces S1, S2 through the outlet ducts 7a, 7b. The outside air (OA) and ambient air (RA) introduced into the housings 31a, 31b are cooled or heated in the heat exchangers 33a, 33b on the load side by refrigerant supplied from the air conditioning unit 2 on the heat source side to the liquid refrigerant interconnecting pipe 11. Having been cooled or heated in the load-side heat exchangers 33a, 33b, the outside air (OA) or outside air (OA), including ambient air (RA), is supplied as supply air (SA) to the air-conditioned spaces S1, S2 through the supply/exhaust air turbines 51a, 51b and the supply air ducts 6a, 6b. In this embodiment, the opening degrees of the return air regulating mechanisms 57a, 57b can be adjusted to control the amount of outside air (OA) drawn in.

[0255] <Refrigerant expulsion operation>

[0257] During the normal operation described above, when refrigerant leaks occur in the air conditioning units 3a and 3b on the load side, the leaking refrigerant is supplied to the air-conditioned spaces S1 and S2, posing a risk of ignition accidents (when the refrigerant is flammable or slightly flammable) or poisoning accidents (when the refrigerant is toxic). Therefore, when the refrigerant leak detection devices 48a and 48b detect refrigerant, a refrigerant expulsion operation is performed to expel the refrigerant, along with air, from the housings 31a and 31b outside the air-conditioned spaces S1 and S2 by means of the supply/extraction air mechanisms. In this embodiment, the refrigerant expulsion operation is performed by actuating the supply/extraction air turbines 51a and 51b, setting the supply/extraction air mechanisms to the extraction position.

[0259] For example, assuming a refrigerant leak has occurred in the air handling unit 3b on the load side (i.e., the refrigerant leak detection device 48b has detected refrigerant), the supply/exhaust air turbine 51b is operated in the exhaust air state in the air handling unit 3b on the load side, as shown in FIG. 8. Specifically, the supply air prevention mechanism 54b and the intake prevention mechanism 56b are closed, the bypass opening/closing mechanism 55b is opened, and the supply/exhaust air turbine 51b is activated. The leaking refrigerant, along with the air in the housing 31b, thus passes through the bypass passage 53b and is discharged to the intake duct 5 (5b). In this embodiment, when the supply/extraction air turbine 51b is operated in the extraction state, ambient air (RA) is drawn into the housing 31b from the air-conditioned space S2 and is therefore discharged to the intake duct 5 (5b) along with the leaking refrigerant. At this time, outside air (OA) is drawn into the housing 31b along with the ambient air (RA) from outside the air-conditioned space S2 through the exhaust duct 8 (8b). In the heat source-side air conditioning unit 2, refrigerant is prevented from being supplied from the heat source-side air conditioning unit 2 to the load-side air conditioning unit 3b, for example, because the compressor 21 is stopped. In the air conditioning unit 3a on the use side, where there is no refrigerant leakage, the refrigerant leaking from the air conditioning unit 3b on the use side is prevented from flowing back into the housing 31a through the intake duct 5 (5a) by closing the return air regulating mechanism 57a.

[0261] (3) Features

[0263] The air conditioning appliances 3a, 3b on the use side of the present embodiment and the air conditioning appliance 1 provided with them have characteristics such as the following.

[0265] In this embodiment, as described above, in the air conditioning units 3a and 3b on the load side, which have the ventilation air conditioning function, and in air conditioning unit 1 provided with the same, when the refrigerant leak detection devices 48a and 48b detect refrigerant, the refrigerant expulsion operation is carried out by means of the air supply/extraction mechanisms to expel the refrigerant, along with the air, from the air-conditioned spaces S1 and S2, from the housings 31a and 31b. Specifically, in this embodiment, the refrigerant expulsion operation is carried out by operating the air supply/extraction turbines 51a and 51b in the air extraction mode. Furthermore, in this embodiment, air conditioning unit 1 is configured by connecting the heat source-side air conditioning unit 2 and the plurality (two in this embodiment) of air conditioning units 3a and 3b on the load side.

[0266] In this embodiment, when a refrigerant leak occurs, it is therefore possible to ensure that the leaking refrigerant is quickly expelled and not supplied to the air-conditioned spaces S1, S2, using the air supply/extraction mechanisms (in this embodiment, by operating the air supply/extraction turbines 51a, 51b in the air extraction state). Furthermore, in this embodiment, when a refrigerant leak has occurred in any of the plurality of air-conditioning units 3a, 3b on the load side, it is possible to ensure that the leaking refrigerant is quickly extracted using the supply/extraction mechanism of the air-conditioning unit 3a or 3b on the load side from which the refrigerant leaked, and that the refrigerant is not supplied to the air-conditioned space S1 or S2 being conditioned by the air-conditioning unit 3a or 3b on the load side from which the refrigerant leaked.

[0267] When the refrigerant is flammable or slightly flammable, ignition accidents in air-conditioned spaces S1, S2 can be suppressed. When the refrigerant is toxic, poisoning accidents in air-conditioned spaces S1, S2 can be suppressed. The incidence of oxygen deficiency accidents in air-conditioned spaces S1, S2 can be suppressed even when the refrigerant is non-flammable, slightly flammable, or toxic.

[0269] This realization also has the <B> and <C> features of the first realization.

[0271] (4) Modifications that are not part of the invention

[0273] In the above described use-side air conditioning units 3a, 3b and air conditioning unit 1 provided with the same (see FIGS. 6 to 8), the gaskets 13a, 13b, 14a, 14b connecting the use-side heat exchangers 33a, 33b to the refrigerant interconnecting pipes are provided inside the housings 31a, 31b. But in examples not part of the invention, there are also cases where the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b, similarly to the use-side air conditioning units 3a, 3b of the first embodiment (FIG. 4). In these cases, when there are refrigerant leaks from joints 13a, 13b, 14a, 14b, the leak occurs in the installation spaces on the use side S3, S4 where the housings 31a, 31b of the use-side air conditioning appliances 3a, 3b are installed.

[0275] In view of this, in the previously described use-side air conditioning units 3a, 3b and the air conditioning unit 1 provided with the same (see FIGS. 6 to 8), the use-side air conditioning units 3a, 3b, similarly to the use-side air conditioning units 3a, 3b according to the modification of the first embodiment, are provided with indoor-outdoor communication mechanisms 47a, 47b, which are capable of switching between an indoor-outdoor communication state allowing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, and an indoor-outdoor non-communication state preventing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, the refrigerant expulsion operation is carried out by setting the mechanisms 47a, 47b of inside-outside communication in the inside-outside communication state.

[0276] Furthermore, in the air handling units 3a, 3b described above and air handling unit 1 provided with them (see FIGS. 6 to 8), the intake duct 5 (5a, 5b) is used to expel leaking liquid refrigerant during the refrigerant expulsion operation, but when a separate duct is connected to housings 31a, 31b, this separate duct can be used for leaking refrigerant during the refrigerant expulsion operation. In this case, outside air (OA) can continue to enter housings 31a, 31b through the intake duct 5 (5a, 5b) even during the refrigerant expulsion operation.

[0278] -Third realization-

[0279] (1) Configuration

[0281] FIG. 9 is a general configuration diagram of an air conditioning unit with air conditioning units 3a, 3b on the use side according to a third embodiment of the invention. FIG. 10 is a control block diagram of air conditioning unit 1 of the third embodiment.

[0283] <Overview>

[0285] Air conditioning appliance 1, which is an air conditioning ventilation system having an air conditioning function to ventilate and condition the interior of a room, mainly has an air conditioning appliance 2 on the heat source side, and a plurality (two in this embodiment) of air conditioning appliances 3a, 3b on the use side.

[0287] Air conditioning unit 1 has a refrigerant circuit 10 through which refrigerant circulates. The refrigerant circuit 10 is configured by connecting the heat source-side air conditioning unit 2 to the use-side air conditioning units 3a and 3b. In this embodiment, the heat source-side air conditioning unit 2 is installed in a location such as the roof of a building, and the use-side air conditioning units 3a and 3b are installed in use-side installation spaces (in this embodiment, use-side installation spaces S3 and S4), such as a building machine room or a space above the roof, corresponding to air-conditioned spaces (in this embodiment, air-conditioned spaces S1 and S2) that are ventilated and conditioned. The heat source-side air conditioning unit 2 and the user-side air conditioning units 3a and 3b are connected via refrigerant interconnecting pipes 11 and 12, thus forming refrigerant circuit 10. The refrigerant sealed within refrigerant circuit 10 is either a mildly flammable refrigerant such as R32, a flammable refrigerant such as propane, or a toxic refrigerant such as ammonia.

[0289] Air conditioning unit 1 has a plurality of air ducts. In this embodiment, air conditioning unit 1 has an intake duct 5 for carrying outside air (OA) into the use-side air conditioning units 3a, 3b from outside the air-conditioned spaces S1, S2, supply air ducts 6a, 6b for supplying supply air (SA) from the use-side air conditioning units 3a, 3b to the air-conditioned spaces S1, S2, and outlet ducts 7a, 7b for taking ambient air (RA) from the air-conditioned spaces S1, S2 into the corresponding use-side air conditioning units 3a, 3b, so that air can be exchanged between the air-conditioned spaces S1, S2 and/or the outside of the air-conditioned spaces S1, S2 and the use-side air conditioning units 3a, 3b. Also connected to the air-conditioned spaces S1, S2 is an exhaust air duct 8 to expel exhaust air (EA) from the air-conditioned spaces S1, S2. The intake duct 5 has intake branch ducts 5a, 5b which branch off to correspond to the air conditioning units 3a, 3b on the use side, and the exhaust air duct 8 has exhaust air branch ducts 8a, 8b which branch off to correspond to the air-conditioned spaces S1, S2.

[0291] <Air conditioning unit on the heat source side>

[0293] The heat source-side air conditioning unit 2, as described above, is connected to the load-side air conditioning units 3a and 3b via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. The configuration of the heat source-side air conditioning unit 2 according to the present embodiment is similar to the configuration of the heat source-side air conditioning unit 2 of the first embodiment described above (see FIG.

[0294] 1) and therefore is not described here.

[0296] <Air conditioning equipment on the use side>

[0298] The load-side air conditioning units 3a and 3b, as described above, are connected to the heat source-side air conditioning unit 2 via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. Furthermore, the load-side air conditioning units 3a and 3b, as described above, are designed to exchange air with the air-conditioned spaces S1 and S2 and/or the outside of the air-conditioned spaces S1 and S2 via air ducts 5 (5a, 5b), 6a, 6b, 7a, and 7b. The following description describes the configuration of the load-side air conditioning unit 3a and omits the description of the configuration of the load-side air conditioning unit 3b, replacing the additional letter “a” with “b” for each component.

[0300] The air conditioning apparatus 3a on the use side mainly comprises a housing 31a, a use-side expansion mechanism 32a, a use-side heat exchanger 33a, a second air supply turbine 61a, a second air exhaust turbine 63a, and a refrigerant leak detection device 48a.

[0302] The housing 31a is installed in the use-side installation space S3, and several ducts 5a, 6a, 7a are connected to the housing 31a. An air supply passage 42a is formed in the housing 31a to accommodate the use-side heat exchanger 33a and the like.

[0304] The load-side expansion mechanism 32a is an electrically adjustable expansion valve that can vary the degree of opening, controlling the flow rate of refrigerant through the load-side heat exchanger 33a. The load-side expansion mechanism 32a is provided within the housing 31a (within the air supply passage 42a in this embodiment). One end of the load-side expansion mechanism 32a is connected to a liquid side of the load-side expansion mechanism 32a, and the other end of the load-side expansion mechanism 32a is connected to the liquid refrigerant interconnecting pipe 11 via a joint 13a. The joint 13a is a pipe joint for connecting the load-side heat exchanger 33a to the refrigerant interconnecting pipes 11 and 12 and, in this embodiment, is provided within the housing 31a (within the air supply passage 42a in this embodiment).

[0306] The load-side heat exchanger 33a is a heat exchanger for cooling or heating the air (RA and/or OA) in the housing 31a by means of the refrigerant supplied from the heat source-side air conditioning unit 2. A load-side heat exchanger 33a is provided within the housing 31a (within the air supply passage 42a in this embodiment). The load-side heat exchanger 33a is connected to the heat source-side air conditioning unit 2 via the refrigerant interconnecting pipes 11 and 12. One liquid side of the load-side heat exchanger 33a is connected to the liquid refrigerant interconnecting pipe 11 via the load-side expansion mechanism 32a and gasket 13a, and one gas side of the load-side heat exchanger 33a is connected to the refrigerant gas interconnecting pipe 12 via gasket 14a. Gasket 14a is a pipe joint for connecting the load-side heat exchanger 33a to the refrigerant gas interconnecting pipe 12 and, in this embodiment, is provided inside the housing 31a (inside the air supply passage 42a in this embodiment).

[0308] The second supply air turbine 61a is a fan provided to draw ambient air (RA) from the air-conditioned space S1, draw outside air (OA) from outside the air-conditioned space S1, and supply supply air (SA) to the air-conditioned space S1. The second supply air turbine 61a is provided within the supply air passage 42a, and an outlet of this turbine is connected to the supply air duct 6a. The second supply air turbine 61a is designed to be driven by a second supply air turbine motor 62a.

[0310] The second exhaust turbine 63a is a fan provided to expel exhaust air (EA) from the air-conditioned space S1. The second exhaust turbine 63a is provided within the air supply passage 42a, and an outlet of this turbine is connected to an outside air inlet (OA) of the housing 31a. The second exhaust turbine 63a is designed to be driven by a second exhaust turbine motor 64a. In addition, an exhaust outlet communication mechanism 65a is provided at the outlet of the second exhaust turbine 63a. This mechanism consists of a communication path to allow communication between the air supply passage 42a and the outlet of the second exhaust turbine 63a, and an air draft regulator located in this communication path. The exhaust air outlet communication mechanism 65a is capable of switching between an outside air intake state, allowing the outside air inlet (OA) of housing 31a to communicate with the air supply duct 42a and permitting outside air (OA) to enter from outside the air-conditioned space S1 by opening the air draft regulator, and an exhaust air state, allowing the outlet of the second exhaust turbine 63a to communicate with the outside air inlet (OA) of housing 31a and permitting exhaust air (EA) to be extracted from the air-conditioned space S1 by closing the air draft regulator. Additionally, a return air regulating mechanism 66a is provided, consisting of an air draft regulator at the outside air inlet (OA) of housing 31a. The return air regulating mechanism 66a can be provided at the intake bypass duct 5a instead of at the outside air inlet (OA) of housing 31a. Therefore, when operating while the second exhaust turbine 63a is stopped and the exhaust air outlet communication mechanism 65a is in the outside air intake state, the second supply air turbine 61a can draw ambient air (RA) from the air-conditioned space S1, draw outside air (OA) from outside the air-conditioned space S1, and supply air (SA) to the air-conditioned space S1. Furthermore, the second exhaust turbine 63a is capable of extracting exhaust air (EA) from the air-conditioned space S1 when operating with the exhaust air outlet communication mechanism 65a in the exhaust air state.

[0311] The air passage 42a described above, mechanisms 65a, 66a and turbines 61a, 63a, when connected with air ducts 5 (5a), 6a, 6b, 7a, 7b, configure a use-side air supply/extraction mechanism for air conditioning appliance 3a to bring ambient air (RA) into the interior of housing 31a from the air-conditioned space S1, bring outside air (OA) into the interior of housing 31a from outside the air-conditioned space S1, supply the air inside housing 31a as supply air (SA) to the air-conditioned space S1, and expel the air inside housing 31a as exhaust air (EA) from the air-conditioned space S1.

[0313] The refrigerant leak detection device 48a is a device for detecting refrigerant. The refrigerant leak detection device 48a is provided within the housing 31a. In this embodiment, the refrigerant leak detection device 48a is provided within the air supply duct 42a in which the load-side heat exchanger 33a is located (in this embodiment, the gaskets 13a, 14a and/or the load-side expansion mechanism 32a). Furthermore, in this embodiment, the refrigerant leak detection device 48a is provided in a lower portion (when the refrigerant is denser than air) of the housing 31a (in this embodiment, the air supply duct 42a) or in an upper portion (when the refrigerant is less dense than air) of the housing 31a (in this embodiment, the air supply passage 42a). FIG. Figure 9 shows a case in which the refrigerant leak detection device 48a is provided at the bottom of housing 31a.

[0315] <Control Device>

[0317] Air conditioning unit 1 has a control device 9 to perform operational control in air conditioning unit 2 on the heat source side and air conditioning units 3a, 3b on the use side, etc. Control device 9 mainly has a control device 92 on the heat source side to control the actions of the components (compressor, etc.) configuring air conditioning unit 2 on the heat source side, and control devices 93a, 93b on the use side to control the actions of the components (fans, refrigerant leak detection devices, etc.) configuring air conditioning units 3a, 3b on the use side. The heat source-side control device 92, with which the heat source-side air conditioning unit 2 is equipped, has a microcomputer and/or memory, etc., for controlling the heat source-side air conditioning unit 2. The load-side control devices 93a and 93b, with which the load-side air conditioning units 3a and 3b are equipped, have microcomputers and/or memory, etc., for controlling the load-side air conditioning units 3a and 3b. The heat source-side control device 92 and the load-side control devices 93a and 93b are connected to allow the exchange of, for example, control signals via a transmission line, and the control device 9 of the air conditioning unit 1 is configured accordingly. In this embodiment, the control devices 92, 93a, 93b are connected via a transmission line, but they are not limited to being connected in this way and can be connected wirelessly or by another connection method.

[0319] (2) Actions

[0321] The following operations are performed on air conditioning unit 1, which has the configuration described above. The operating controls of air conditioning unit 1, described below, are performed by control device 9.

[0323] <Normal operation>

[0325] In normal operation, an operation is performed such that outside air (OA) is introduced into housings 31a, 31b from outside the air-conditioned spaces S1, S2, ambient air (RA) is introduced into housings 31a, 31b from the air-conditioned spaces S1, S2, and the air is cooled or heated in the use-side heat exchangers 33a, 33b and then supplied as supply air (SA) to the air-conditioned spaces S1, S2, as shown in FIG. 9. In this embodiment, exhaust air (EA) exits the air-conditioned spaces S1, S2 through the exhaust air duct 8 (8a, 8b) connected to the air-conditioned spaces S1, S2. Specifically, an operational check as follows is performed on the components of air conditioning unit 1.

[0327] When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being cooled in the use-side heat exchangers 33a, 33b, in the heat source-side air conditioning unit 2, the switching mechanism 23 is switched to the air-cooling operating state (the state shown by the solid lines of the switching mechanism 23 in FIG.

[0328] 9), and the compressor 21 and the fan 25 on the heat source side are actuated. When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being heated in the use-side heat exchangers 33a, 33b in the air conditioning unit 2 on the heat source side, the switching mechanism 23 is switched to the air heating operating state (the state shown by the dashed lines of the switching mechanism 23 in FIG. 9), and the compressor 21 and the fan 25 on the heat source side are actuated. In this embodiment, the actions of the refrigerant circuit components 10, etc., are the same as the actions of the refrigerant circuit components 10, etc., of the first embodiment and are therefore not described here.

[0330] In the air conditioning units 3a, 3b on the use side at this time, the second exhaust air turbines 63a, 63b stop, the exhaust air outlet communication mechanisms 65a, 65b and the return air regulating mechanisms 66a, 66b open, and the second supply air turbines 61a, 61b are activated. Specifically, the second supply air turbines 61a, 61b operate in the outside air intake state. Due to these actions, outside air (OA) is introduced into the air supply ducts 42a, 42b of the housings 31a, 31b from outside the air-conditioned spaces S1, S2 through the inlet duct 5 (5a, 5b), and ambient air (RA) is introduced into the air supply ducts 42a, 42b of the housings 31a, 31b from the air-conditioned spaces S1, S2 through the outlet ducts 7a, 7b. The outside air (OA) and ambient air (RA) entering the housings 31a, 31b are cooled or heated in the load-side heat exchangers 33a, 33b by means of the refrigerant supplied from the heat source-side air conditioning unit 2 to the liquid refrigerant interconnecting pipe 11. Having been cooled or heated in the load-side heat exchangers 33a, 33b, the outside air (OA) or outside air (OA), including ambient air (RA), is supplied as supply air (SA) to the air-conditioned spaces S1, S2 through the second supply air turbines 61a, 61b and the supply air ducts 6a, 6b. In this embodiment, the opening degrees of the return air regulating mechanisms 66a, 66b can be adjusted to control the amount of outside air (OA) drawn in.

[0332] <Refrigerant expulsion operation>

[0334] During the normal operation described above, when refrigerant leaks occur in the air conditioning units 3a and 3b on the load side, the leaking refrigerant is supplied to the air-conditioned spaces S1 and S2, posing a risk of ignition accidents (when the refrigerant is flammable or slightly flammable) or poisoning accidents (when the refrigerant is toxic). Therefore, when the refrigerant leak detection devices 48a and 48b detect refrigerant, a refrigerant expulsion operation is performed to expel the refrigerant, along with air, from the housings 31a and 31b outside the air-conditioned spaces S1 and S2, using the air supply/extraction mechanisms. In this embodiment, the refrigerant expulsion operation is performed by actuating the second air extraction turbines 63a and 63b, setting the air supply/extraction mechanisms to the air extraction position.

[0336] For example, assuming a case where a refrigerant leak has occurred in the air conditioning unit 3b on the use side (i.e., the refrigerant leak detection device 48b has detected refrigerant), the second exhaust fan 63b is operated in exhaust mode in the air conditioning unit 3b on the use side, as shown in FIG. 11. Specifically, the exhaust outlet communication mechanism 65a is closed, and the second exhaust fan 63b is operated. The leaked refrigerant, along with the air in housing 31b, is thus discharged into the intake duct 5 (5b). At this time, outside air (OA) is drawn into housing 31b along with ambient air (RA) from outside the air-conditioned space S2 through the exhaust duct 8 (8b). The second air supply turbine 61b is stopped, preventing the supply of leaking refrigerant to the air-conditioned space S2. In this embodiment, when the second air exhaust turbine 63b is operated, ambient air (RA) is drawn into the housing 31b from the air-conditioned space S2, and this ambient air (RA) is discharged into the inlet duct 5 (5b) along with the leaking refrigerant. In the heat source-side air conditioning unit 2, the supply of refrigerant from the heat source-side air conditioning unit 2 to the load-side air conditioning unit 3b is prevented, for example, because the compressor 21 is stopped. In the air conditioning unit 3a on the use side, where there is no refrigerant leakage, the refrigerant leaking from the air conditioning unit 3b on the use side is prevented from flowing back into the housing 31a through the intake duct 5 (5a) by closing the return air regulating mechanism 66a.

[0338] (3) Features

[0340] The air conditioning appliances 3a, 3b on the use side of the present embodiment and the air conditioning appliance 1 provided with them have characteristics such as the following.

[0342] In this embodiment, as described above, in the air conditioning units 3a and 3b on the load side, which have the ventilation air conditioning function, and in air conditioning unit 1 provided with the same, when the refrigerant leak detection devices 48a and 48b detect refrigerant, the refrigerant expulsion operation is carried out by means of the air supply/extraction mechanisms to expel the refrigerant, along with the air, from the air-conditioned spaces S1 and S2, from the housings 31a and 31b. Specifically, in this embodiment, the refrigerant expulsion operation is carried out by operating the second air extraction turbines 63a and 63b. Furthermore, in this embodiment, air conditioning unit 1 is configured by connecting the heat source-side air conditioning unit 2 and the plurality (two in this embodiment) of air conditioning units 3a and 3b on the load side.

[0344] In this embodiment, when a refrigerant leak occurs, it is therefore possible to ensure that the leaking refrigerant is quickly extracted and not supplied to the air-conditioned spaces S1 and S2, using the air supply/extraction mechanisms (in this embodiment, by operating the second air extraction turbines 63a and 63b). Furthermore, in this embodiment, when a refrigerant leak occurs in any of the plurality of air-conditioning units 3a and 3b on the load side, it is possible to ensure that the leaking refrigerant is quickly extracted using the supply/extraction mechanism of the air-conditioning unit 3a or 3b on the load side from which the leak occurred, and that the refrigerant is not supplied to the air-conditioned space S1 or S2 being conditioned by the air-conditioning unit 3a or 3b on the load side from which the leak occurred.

[0346] When the refrigerant is flammable or slightly flammable, ignition accidents in air-conditioned spaces S1, S2 can be suppressed. When the refrigerant is toxic, poisoning accidents in air-conditioned spaces S1, S2 can be suppressed. The incidence of oxygen deficiency accidents in air-conditioned spaces S1, S2 can be suppressed even when the refrigerant is non-flammable, slightly flammable, or toxic.

[0348] This realization also has the <B> and <C> features of the first realization.

[0350] (4) Modifications that are not part of the invention

[0352] In the above described use-side air conditioning units 3a, 3b and air conditioning unit 1 provided with the same (see FIGS. 9 to 11), the gaskets 13a, 13b, 14a, 14b connecting the use-side heat exchangers 33a, 33b to the refrigerant interconnecting pipes are provided inside the housings 31a, 31b. But in examples not part of the invention, there are also cases where the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b, similarly to the use-side air conditioning units 3a, 3b of the first embodiment (FIG. 4). In these cases, when there are refrigerant leaks from joints 13a, 13b, 14a, 14b, the leak occurs in the installation spaces on the use side S3, S4 where the housings 31a, 31b of the use-side air conditioning appliances 3a, 3b are installed.

[0354] In view of this, in the previously described use-side air conditioning units 3a, 3b and the air conditioning unit 1 provided with the same (see FIGS. 9 to 11), the use-side air conditioning units 3a, 3b, similarly to the use-side air conditioning units 3a, 3b according to the modification of the first embodiment, are provided with indoor-outdoor communication mechanisms 47a, 47b, which are capable of switching between an indoor-outdoor communication state allowing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, and an indoor-outdoor non-communication state preventing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, the refrigerant expulsion operation is carried out by setting the mechanisms 47a, 47b of inside-outside communication in the inside-outside communication state.

[0355] -Fourth realization-

[0356] (1) Configuration

[0358] FIG. 12 is a general configuration diagram of an air conditioning unit with air conditioning units 3a, 3b on the use side according to a fourth embodiment of the invention. FIG. 13 is a control block diagram of air conditioning unit 1 of the fourth embodiment.

[0360] <Overview>

[0362] Air conditioning appliance 1, which is an air conditioning ventilation system having an air conditioning function to ventilate and condition the interior of a room, mainly has an air conditioning appliance 2 on the heat source side, and a plurality (two in this embodiment) of air conditioning appliances 3a, 3b on the use side.

[0364] Air conditioning unit 1 has a refrigerant circuit 10 through which refrigerant circulates. The refrigerant circuit 10 is configured by connecting the heat source-side air conditioning unit 2 to the use-side air conditioning units 3a and 3b. In this embodiment, the heat source-side air conditioning unit 2 is installed in a location such as the roof of a building, and the use-side air conditioning units 3a and 3b are installed in use-side installation spaces (in this embodiment, use-side installation spaces S3 and S4), such as a building machine room or a space above the roof, corresponding to air-conditioned spaces (in this embodiment, air-conditioned spaces S1 and S2) that are ventilated and conditioned. The heat source-side air conditioning unit 2 and the user-side air conditioning units 3a and 3b are connected via refrigerant interconnecting pipes 11 and 12, thus forming refrigerant circuit 10. The refrigerant sealed within refrigerant circuit 10 is either a mildly flammable refrigerant such as R32, a flammable refrigerant such as propane, or a toxic refrigerant such as ammonia.

[0366] Air conditioning unit 1 has a plurality of air ducts. In this embodiment, air conditioning unit 1 has an intake duct 5 to bring outside air (OA) into the air conditioning units 3a, 3b on the use side from outside the air-conditioned spaces S1, S2, supply air ducts 6a, 6b to supply supply air (SA) from the air conditioning units 3a, 3b on the use side to the air-conditioned spaces S1, S2, outlet ducts 7a, 7b to draw ambient air (RA) from the air-conditioned spaces S1, S2 into the corresponding air conditioning units 3a, 3b on the use side, and an exhaust air duct 8 to extract exhaust air (EA) from the air-conditioned units 3a, 3b on the use side outside the air-conditioned spaces S1, S2, so that air can be exchanged between the air-conditioned spaces S1, S2 and/or the outside of the air-conditioned spaces S1, S2 and the air conditioning units 3a, 3b on the use side. The intake duct 5 has intake branch ducts 5a, 5b that correspond to the air conditioning units 3a, 3b on the use side, and the exhaust air duct 8 has exhaust air branch ducts 8a, 8b that correspond to the air conditioning units 3a, 3b on the use side.

[0368] <Air conditioning unit on the heat source side>

[0370] The heat source-side air conditioning unit 2, as described above, is connected to the load-side air conditioning units 3a and 3b via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. The configuration of the heat source-side air conditioning unit 2 according to the present embodiment is similar to the configuration of the heat source-side air conditioning unit 2 of the first embodiment described above (see FIG. 1) and is therefore not described herein.

[0372] <Air conditioning equipment on the use side>

[0374] The load-side air conditioning units 3a and 3b, as described above, are connected to the heat source-side air conditioning unit 2 via refrigerant interconnecting pipes 11 and 12, forming part of the refrigerant circuit 10. Furthermore, the load-side air conditioning units 3a and 3b, as described above, are designed to exchange air with the air-conditioned spaces S1 and S2 and/or the outside of the air-conditioned spaces S1 and S2 via air ducts 5 (5a, 5b), 6a, 6b, 7a, 7b, and 8 (8a, 8b). In the following description, the configuration of the air conditioning unit 3a on the use side is described, and the description of the configuration of the air conditioning unit 3b on the use side is omitted, replacing the additional letter “a” with “b” for each component.

[0376] The use-side air conditioning apparatus 3a mainly comprises a housing 31a, a use-side expansion mechanism 32a, a use-side heat exchanger 33a, a third air supply turbine 71a, a third air exhaust turbine 73a, and a refrigerant leak detection device 48a.

[0377] The housing 31a is installed in the installation space on the use side S3, and several ducts 5a, 6a, 7a, 8a are connected to the housing 31a. A space is formed in the housing 31a to accommodate the use-side heat exchanger 33a and the like.

[0379] The load-side expansion mechanism 32a is an electrically operated expansion valve that, by controlling the degree of opening, can vary the flow rate of the refrigerant flowing through the load-side heat exchanger 33a. The load-side expansion mechanism 32a is provided within the housing 31a. One end of the load-side expansion mechanism 32a is connected to a liquid side of the load-side expansion mechanism 32a, and the other end of the load-side expansion mechanism 32a is connected to the liquid refrigerant interconnecting tube 11 via a joint 13a. The joint 13a is a tube joint for connecting the load-side heat exchanger 33a to the refrigerant interconnecting tubes 11 and 12 and, in this embodiment, is provided within the housing 31a.

[0381] The load-side heat exchanger 33a is a heat exchanger for cooling or heating air (RA and/or OA) in the housing 31a by means of refrigerant supplied from the heat source-side air conditioning unit 2. The load-side heat exchanger 33a is provided within the housing 31a. The load-side heat exchanger 33a is connected to the heat source-side air conditioning unit 2 via refrigerant interconnecting pipes 11 and 12. One liquid side of the load-side heat exchanger 33a is connected to the liquid refrigerant interconnecting pipe 11 via the load-side expansion mechanism 32a and gasket 13a, and one gas side of the load-side heat exchanger 33a is connected to the refrigerant gas interconnecting pipe 12 via gasket 14a. Joint 14a is a tube joint for connecting the load-side heat exchanger 33a to the refrigerant gas interconnecting tube 12 and, in this embodiment, is provided within the housing 31a. The space within the housing 31a is divided into an air supply passage 42a and an air exhaust passage 44a. The air supply duct 42a communicates with the intake duct 5 (5a) and the air supply duct 6a, and the air exhaust duct 44a communicates with the outlet duct 7a and the air exhaust duct 8 (8a). The load-side expansion mechanism 32a and the load-side heat exchanger 33a are provided within the air supply duct 42a within the space inside the housing 31a, and in this embodiment, joints 13a and 14a are also provided within the air supply duct 42a. Therefore, the use-side heat exchanger 33a is designed to cool or heat the air inside the air supply duct 42a.

[0383] The third supply air turbine 71a is a fan provided to draw outside air (OA) from outside the air-conditioned space S1 and supply supply air (SA) to the air-conditioned space S1. The third supply air turbine 71a is provided within the supply air passage 42a, and an outlet of this turbine is connected to the supply air duct 6a. The third supply air turbine 71a is designed to be driven by a third supply air turbine motor 72a.

[0385] The third exhaust turbine 73a is a fan provided so as to be capable of taking ambient air (RA) from the air-conditioned space S1, returning some of the ambient air (RA) to the outside air (OA) taken by the third supply air turbine 73a, and expelling the remainder of the ambient air (RA) as exhaust air (EA) from the air-conditioned space S1. The third exhaust turbine 73a is provided within the exhaust air passage 44a, and an outlet of this turbine is connected to the exhaust air duct 8 (8a). The third exhaust turbine 73a is designed to be driven by a third exhaust turbine motor 74a. Furthermore, at the outlet of the third exhaust turbine 73a, an exhaust outlet communication mechanism 75a is provided. This mechanism consists of a communication path to allow communication between the air supply passage 42a and the outlet of the third exhaust turbine 73a, and an air draft regulator located within this communication path. The exhaust outlet communication mechanism 75a is capable of switching between: a partial extraction state to allow the outlet of the third exhaust turbine 73a to communicate with the air supply passage 42a, returning some of the ambient air (RA) to the outside air (OA) within the air supply duct 42a, and expelling the remaining ambient air (RA) as exhaust air (EA) from the air-conditioned space S1 by opening the air draft regulator; and a full extraction state that prevents the outlet of the third exhaust turbine 73a from communicating with the supply air passage 42a, and extracts all ambient air (RA) as exhaust air (EA) from the air-conditioned space S1, closing the air draft regulator. Additionally, a supply/extraction air communication mechanism 76a is provided in the housing 31a, consisting of a communication path to allow the supply air passage 42a and the exhaust air passage 44a to communicate, and an air draft regulator located in this communication path. The supply/extraction air communication mechanism 76a is capable of switching between a supply and extraction air communication state, allowing supply air step 42a and extraction air step 44a to communicate by opening the air draft regulator, and a non-communication state, preventing supply air step 42a and extraction air step 44a from communicating by closing the air draft regulator. A return air regulating mechanism 77a, consisting of an air draft regulator, is provided at an extraction air outlet (EA) of housing 31a. This return air regulating mechanism 77a can be provided at the extraction air duct 8a instead of at the extraction air outlet (EA) of housing 31a.

[0387] The air ducts 42a, 44a, mechanisms 75a, 76a, 77a and turbines 71a, 73a described above, when connected with air ducts 5 (5a), 6a, 6b, 7a, 7b, 8 (8a), configure a use-side air supply/extraction mechanism 3a for taking outside air (OA) from outside the air-conditioned space S1, supplying supply air (SA) to the air-conditioned space S1, taking ambient air (RA) from the air-conditioned space S1, returning part of the ambient air (RA) to the outside air (OA) and extracting the remainder of the ambient air (RA) as exhaust air (EA) from the air-conditioned space S1.

[0389] The refrigerant leak detection device 48a is a device for detecting refrigerant. The refrigerant leak detection device 48a is provided within the housing 31a. In this embodiment, the refrigerant leak detection device 48a is provided within the air supply duct 42a in which the service-side heat exchanger 33a is located (in this embodiment, the seals 13a, 14a and/or the service-side expansion mechanism 32a). Furthermore, in this embodiment, the refrigerant leak detection device 48a is provided in a lower portion (when the refrigerant is denser than air) of the housing 31a (in this embodiment, the air supply duct 42a) or in an upper portion (when the refrigerant is less dense than air) of the housing 31a (in this embodiment, the air supply passage 42a). FIG. Figure 12 shows a case in which the refrigerant leak detection device 48a is provided at the bottom of housing 31a.

[0390] <Control Device>

[0392] Air conditioning unit 1 has a control device 9 to perform operational control in air conditioning unit 2 on the heat source side and air conditioning units 3a, 3b on the use side, etc. Control device 9 mainly has a heat source-side control device 92 to control the actions of the components (compressor, etc.) configuring air conditioning unit 2 on the heat source side, and use-side control devices 93a, 93b to control the actions of the components (fans, refrigerant leak detection devices, etc.) configuring air conditioning units 3a, 3b on the use side. The heat source-side control device 92, with which the heat source-side air conditioning unit 2 is equipped, has a microcomputer and/or memory, etc., for controlling the heat source-side air conditioning unit 2. The load-side control devices 93a and 93b, with which the load-side air conditioning units 3a and 3b are equipped, have microcomputers and/or memory, etc., for controlling the load-side air conditioning units 3a and 3b. The heat source-side control device 92 and the load-side control devices 93a and 93b are connected to allow the exchange of, for example, control signals via a transmission line, and the control device 9 of the air conditioning unit 1 is configured accordingly. In this embodiment, the control devices 92, 93a, 93b are connected via a transmission line, but they are not limited to being connected in this way and can be connected wirelessly or by another connection method.

[0394] (2) Actions

[0396] The following operations are performed on air conditioning unit 1, which has the configuration described above. The operating controls of air conditioning unit 1, described below, are performed by control device 9.

[0398] <Normal operation>

[0400] Under normal operation, an operation is performed such that outside air (OA) is introduced into housings 31a, 31b from outside the air-conditioned spaces S1, S2, ambient air (RA) is introduced into housings 31a, 31b from the air-conditioned spaces S1, S2, part of the ambient air (RA) is returned to the outside air (OA), the return air (OA and part of RA) is cooled or heated in the use-side heat exchangers 33a, 33b and then supplied as supply air (SA) to the air-conditioned spaces S1, S2, and the remaining ambient air (RA) is expelled as exhaust air (EA) outside the air-conditioned space S1, as shown in FIG. 12. Specifically, an operational check as follows is performed on the components of air conditioning unit 1.

[0401] When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being cooled in the use-side heat exchangers 33a, 33b in the heat source-side air conditioning unit 2, the switching mechanism 23 is switched to the air-cooling operating state (the state shown by the solid lines of the switching mechanism 23 in FIG.

[0402] 12), and the compressor 21 and the fan 25 on the heat source side are actuated. When air is supplied as supply air (SA) to the air-conditioned spaces S1, S2 after being heated in the use-side heat exchangers 33a, 33b in the air conditioning unit 2 on the heat source side, the switching mechanism 23 is switched to the air heating operating state (the state shown by the dashed lines of the switching mechanism 23 in FIG. 12), and the compressor 21 and the fan 25 on the heat source side are actuated. In this embodiment, the actions of the refrigerant circuit components 10, etc., are the same as the actions of the refrigerant circuit components 10, etc., of the first embodiment and are therefore not described here.

[0404] In the air conditioning appliances 3a, 3b on the use side at this time, the exhaust air outlet communication mechanisms 75a, 75b and the return air regulation mechanisms 77a, 77b are open, the supply/extraction air communication mechanism 76a is closed, and the third supply air turbines 71a, 71b and the third exhaust air turbines 73a, 73b are actuated. Due to these actions, outside air (OA) is introduced into the air supply ducts 42a, 42b of housings 31a, 31b from outside the air-conditioned spaces S1, S2 through the inlet duct 5 (5a, 5b), and ambient air (RA) is introduced into the air exhaust ducts 44a, 44b of housings 31a, 31b from the air-conditioned spaces S1, S2 through the outlet ducts 7a, 7b. The ambient air (RA) introduced into housings 31a, 31b is exhausted by the third air exhaust turbines 73a, 73b to the outlets of the housings. Part of the ambient air (RA) sent to the outlets of the third air extraction turbines 73a, 73b is sent through the air extraction outlet communication mechanisms 75a, 75b to the air supply passage 42a to mix with the outside air (OA) according to the opening degrees of the air draft regulators of the return air regulating mechanisms 77a, 77b. The remaining ambient air (RA) is expelled as exhaust air (EA) from the air-conditioned spaces S1, S2 through the air extraction duct 8 (8a, 8b). The combined ambient air (RA) and outside air (OA) are then cooled or heated in the load-side heat exchangers 33a, 33b by refrigerant supplied from the heat source-side air conditioning unit 2 via the liquid refrigerant interconnecting pipe 11. Having been cooled or heated in the use-side heat exchangers 33a, 33b, the outside air (OA), including ambient air (RA), is supplied as supply air (SA) to the air-conditioned spaces S1, S2 via the third air supply turbines 71a, 71b and the air supply ducts 6a, 6b.

[0406] <Refrigerant expulsion operation>

[0408] During the normal operation described above, when refrigerant leaks occur in the air conditioning units 3a and 3b on the load side, the leaking refrigerant is supplied to the air-conditioned spaces S1 and S2, posing a risk of ignition accidents (when the refrigerant is flammable or slightly flammable) or poisoning accidents (when the refrigerant is toxic). Therefore, when the refrigerant leak detection devices 48a and 48b detect refrigerant, a refrigerant expulsion operation is performed to expel the refrigerant, along with air, from the housings 31a and 31b outside the air-conditioned spaces S1 and S2, using the air supply/extraction mechanisms. In this embodiment, the refrigerant expulsion operation is performed by actuating the third air extraction turbines 73a and 73b, thus configuring the air supply/extraction mechanisms.

[0410] For example, assuming a refrigerant leak has occurred in the air conditioning unit 3b on the use side (i.e., the refrigerant leak detection device 48b has detected refrigerant), the third exhaust turbine 73b in the air conditioning unit 3b on the use side is operated, as shown in FIG. 14. Specifically, the exhaust outlet communication mechanism 75b is closed, the supply/exhaust communication mechanism 76b is opened, and the third exhaust turbine 73b is operated. The leaking refrigerant, along with the air in the housing 31b, is thus discharged to the exhaust duct 8 (8b) through the supply air duct 42b and the exhaust air duct 44b. The third supply air turbine 71b stops, and the supply of leaking refrigerant to the air-conditioned space S2 is prevented. In this embodiment, when the third exhaust turbine 73b is operated, ambient air (RA) is drawn into the housing 31b from the air-conditioned space S2, and this ambient air (RA) is extracted along with any leaking refrigerant through the exhaust air duct 8 (8b). In the heat source-side air conditioning unit 2, refrigerant is prevented from being supplied from the heat source-side air conditioning unit 2 to the load-side air conditioning unit 3b, for example, because the compressor 21 is stopped. In the load-side air conditioning unit 3a, where there is no refrigerant leakage, the refrigerant leaking from the load-side air conditioning unit 3b is prevented from flowing back into the housing 31a through the exhaust air duct 8 (8a) by closing the return air regulating mechanism 77a.

[0412] (3) Features

[0414] The air conditioning appliances 3a, 3b on the use side of the present embodiment and the air conditioning appliance 1 provided with them have characteristics such as the following.

[0416] In this embodiment, as described above, in the air conditioning units 3a and 3b on the load side, which have the ventilation air conditioning function, and in air conditioning unit 1 provided with the same, when the refrigerant leak detection devices 48a and 48b detect refrigerant, the refrigerant expulsion operation is carried out by means of the air supply/extraction mechanisms to expel the refrigerant, along with the air, from the air-conditioned spaces S1 and S2, from the housings 31a and 31b. Specifically, in this embodiment, the refrigerant expulsion operation is carried out by operating the third air extraction turbines 73a and 73b. Furthermore, in this embodiment, air conditioning unit 1 is configured by connecting the heat source-side air conditioning unit 2 and the plurality (two in this embodiment) of air conditioning units 3a and 3b on the load side.

[0418] In this embodiment, when a refrigerant leak occurs, it is therefore possible to ensure that the leaking refrigerant is quickly extracted and not supplied to the air-conditioned spaces S1 and S2, using the air supply/extraction mechanisms (in this embodiment, by operating the third air extraction turbines 73a and 73b). Furthermore, in this embodiment, when a refrigerant leak occurs in any of the plurality of air-conditioning units 3a and 3b on the load side, it is possible to ensure that the leaking refrigerant is quickly extracted using the supply/extraction mechanism of the air-conditioning unit 3a or 3b on the load side from which the leak occurred, and that the refrigerant is not supplied to the air-conditioned space S1 or S2 being conditioned by the air-conditioning unit 3a or 3b on the load side from which the leak occurred.

[0420] When the refrigerant is flammable or slightly flammable, ignition accidents in air-conditioned spaces S1, S2 can be suppressed. When the refrigerant is toxic, poisoning accidents in air-conditioned spaces S1, S2 can be suppressed. The incidence of oxygen deficiency accidents in air-conditioned spaces S1, S2 can be suppressed even when the refrigerant is non-flammable, slightly flammable, or toxic.

[0421] This realization also has the <B> and <C> features of the first realization.

[0422] (4) Modifications that are not part of the invention

[0423] In the above described use-side air conditioning units 3a, 3b and air conditioning unit 1 provided with the same (see FIGS. 12 to 14), the gaskets 13a, 13b, 14a, 14b connecting the use-side heat exchangers 33a, 33b to the refrigerant interconnecting pipes are provided inside the housings 31a, 31b. But in examples not part of the invention, there are also cases where the gaskets 13a, 13b, 14a, 14b are provided outside the housings 31a, 31b, similarly to the use-side air conditioning units 3a, 3b of the first embodiment (FIG. 4). In these cases, when there are refrigerant leaks from joints 13a, 13b, 14a, 14b, the leak occurs in the installation spaces on the use side S3, S4 where the housings 31a, 31b of the use-side air conditioning appliances 3a, 3b are installed.

[0424] In view of this, in the previously described use-side air conditioning units 3a, 3b and the air conditioning unit 1 provided with the same (see FIGS. 12 to 14), the use-side air conditioning units 3a, 3b, similarly to the use-side air conditioning units 3a, 3b according to the modification of the first embodiment, are provided with indoor-outdoor communication mechanisms 47a, 47b, which are capable of switching between an indoor-outdoor communication state allowing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, and a non-indoor-outdoor communication state preventing communication between the use-side installation spaces S3, S4 and the interiors of housings 31a, 31b, the refrigerant expulsion operation is carried out by placing the mechanisms 47a, 47b of inside-outside communication in the inside-outside communication state.

[0425] Industrial applicability

[0426] The present invention is broadly applicable to: use-side air conditioning appliances having use-side heat exchangers for cooling or heating air inside housings by means of refrigerant supplied from a heat source-side air conditioning appliance, and air supply/extraction mechanisms for bringing air into the housings from air-conditioned spaces or outside of air-conditioned spaces and for supplying air from inside the housings to air-conditioned spaces or outside of air-conditioned spaces; and air conditioning appliances that are provided with such use-side air conditioning appliances.

[0427] List of reference numbers

[0428] 1 Air conditioning unit

[0429] 2 Air conditioning unit on the heat source side

[0430] 3a, 3b Air conditioning equipment on the use side

[0431] 11, 12 Refrigerant interconnection tubes

[0432] 13a, 13b, 14a, 14b Together

[0433] 31a, 31b Housings

[0434] 33a, 33b Use-side heat exchangers

[0435] 35a, 35b First air supply turbines

[0436] 37a, 37b First air extraction turbines

[0437] 47a, 47b Internal-external communication mechanisms

[0438] 48a, 48b, 49a, 49b Refrigerant leak detection devices

[0439] 51a, 51b Air supply/extraction turbines

[0440] 61a, 61b Second air supply turbines

[0441] 63a, 63b Second air extraction turbines

[0442] 71a, 71b Third air supply turbines

[0443] 73a, 73b Third air extraction turbines

[0444] List of references

[0445] Patent Bibliography

[0446] Patent Bibliography 1: Japanese Patent Pending Publication No. 2000-220877

Claims (10)

1. CLAIMS 1. An air conditioning apparatus (1) comprising an air conditioning unit (2) on the heat source side to supply refrigerant; a plurality of air conditioning appliances (3a, 3b) on the use side, each comprising a refrigerant leak detection device (48a, 48b, 49a, 49b) for detecting the refrigerant; wherein each use-side air conditioning unit (3a, 3b) comprises: a housing (31a, 31b) configured to be installed in a use-side installation space (S3, S4); a use-side heat exchanger (33a, 33b), provided within the housing (31a, 31b), for cooling or heating the air within the housing (31a, 31b) by using a refrigerant supplied from a heat-source-side air conditioning apparatus (2); and an air supply/extraction mechanism for bringing ambient air (RA) into each housing (31a, 31b) from a corresponding air-conditioned space (S1, S2), bringing outside air (OA) into each housing (31a, 31b) from outside the air-conditioned spaces (S1, S2), supplying air into each housing (31a, 31b) as supply air (SA) to the air-conditioned spaces (S1, S2), and expelling air into each housing (31a, 31b) as exhaust air (EA) outside the air-conditioned spaces (S1, S2); wherein the air supply/extraction mechanism is configured to perform a refrigerant expulsion operation to expel the refrigerant out of the air-conditioned spaces (S1, S2) together with the air inside each housing (31a, 31b) when the refrigerant leak detection device (48a, 48b, 49a, 49b) has detected the refrigerant; wherein each load-side heat exchanger (33a, 33b) is configured to connect to the heat source-side air conditioning unit (2) via a refrigerant interconnecting pipe (11, 12); and wherein a gasket (13a, 13b, 14a, 14b) is provided within each housing (31a, 31b) for connecting each load-side heat exchanger (33a, 33b) to each refrigerant interconnecting pipe (11, 12); wherein a respective refrigerant leak detection device (48a, 48b, 49a, 49b) is provided within each housing (31a, 31b) of the load-side air conditioning apparatus (3a, 3b); where the air conditioning apparatus (1) further comprises an intake duct (5) for bringing outside air (OA) into the use-side air conditioning units (3a, 3b) from outside the air-conditioned spaces (S1, S2), and an exhaust air duct (8) for expelling exhaust air (EA) from the use-side air-conditioned spaces (S1, S2) of the use-side air conditioning units (3a, 3b); wherein the intake duct (5) has intake branch ducts (5a, 5b) that branch off to the air conditioning appliances (3a, 3b) on the use side, and the exhaust air duct (8) has exhaust air branch ducts (8a, 8b) that branch off to the air conditioning appliances (3a, 3b) on the use side; where the air conditioning unit also includes an air supply duct (6a, 6b) to supply supply air (SA) from the air conditioning units (3a, 3b) on the use side to the air-conditioned spaces (S1, S2), an outlet duct (7a, 7b) to carry ambient air (RA) from the air-conditioned spaces (S1, S2) to the corresponding air conditioning units (3a, 3b) on the use side, wherein the air supply/extraction mechanism is configured to supply air from inside the housing (31a, 31b) as supply air (SA) to the air-conditioned space (S1, S2) through the air supply duct (6a, 6b) connecting the housing (31a, 31b) and the air-conditioned space (S1, S2); further comprising the air conditioning apparatus (1) an air return regulating mechanism (77a) consisting of an air draft regulator provided in an outlet for the extraction air (EA) of the housing (31a) or in the air extraction duct (8a). 2. The air conditioning apparatus (1) according to claim 1 wherein Within the housing (31a, 31b) a total heat exchanger (34a, 34b) is provided to perform the heat exchange between the outside air and the ambient air; The air supply/extraction mechanism has a first air supply turbine (35a, 35b) provided to draw outside air from outside the air-conditioned space and supply the supply air to the air-conditioned space, and a first air extraction turbine (37a, 37b) provided to draw ambient air from the air-conditioned space and expel exhaust air from the air-conditioned space; and The first air extraction turbine is configured to perform the coolant expulsion operation. 3. The air conditioning apparatus (1) according to claim 1, wherein The air supply/extraction mechanism has an air supply/extraction turbine (51a, 51b) provided to be able to switch between an air supply state to take in ambient air from the air-conditioned space, take in outside air from outside the air-conditioned space, and supply supply air to the air-conditioned space, and an air extraction state to expel exhaust air from the air-conditioned space; and The air supply/extraction turbine in the air extraction state is configured to perform the coolant expulsion operation. 4. The air conditioning apparatus (1) according to claim 1, wherein The air supply/extraction mechanism has a second air supply turbine (61a, 61b) provided so as to be able to draw ambient air from the air-conditioned space, draw outside air from outside the air-conditioned space, and supply the supply air to the air-conditioned space, and a second air extraction turbine (63a, 63b) provided so as to be able to expel the extraction air from the air-conditioned space; and The second air extraction turbine is configured to perform coolant expulsion. 5. The air conditioning apparatus (1) according to claim 1, wherein The air supply/extraction mechanism has a third air supply turbine (71a, 71b) provided so as to be able to take outside air from outside the air-conditioned space and supply supply air to the air-conditioned space, and a third air extraction turbine (73a, 73b) provided so as to be able to take ambient air from the air-conditioned space, return some of the ambient air to the outside air taken by the third air supply turbine and expel a remainder of the ambient air as exhaust air from the air-conditioned space; and the third air extraction turbine is configured to perform the refrigerant expulsion operation. 6. The air conditioning apparatus (1) according to any one of claims 1 to 5, wherein the refrigerant is denser than air; and The refrigerant leak detection device (48a, 48b, 49a, 49b) is provided in a lower part of the housing (31a, 31b). 7. The air conditioning apparatus (1) according to any one of claims 1 to 5, wherein the refrigerant is less dense than air; and The refrigerant leak detection device (48a, 48b, 49a, 49b) is provided on a top part of the housing (31a, 31b). 8. The air conditioning apparatus (1) according to any one of claims 1 to 7 comprising the refrigerant, the refrigerant being flammable or slightly flammable. 9. The air conditioning apparatus (1) according to any one of claims 1 to 7 which includes the refrigerant, the refrigerant being toxic. 10. The air conditioning apparatus (1) according to any one of claims 1 to 7 comprising the refrigerant, the refrigerant not being flammable, slightly flammable or toxic.