JP6417750B2 - Cooling and heating simultaneous operation type air conditioner - Google Patents

Description

  The present invention relates to a cooling / heating simultaneous operation type air conditioner, and more particularly, to a cooling / heating simultaneous operation type air conditioner configured by connecting a plurality of utilization units, a branch unit, and a heat source unit via three refrigerant communication pipes. .

  Conventionally, as shown in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2009-299910), a plurality of indoor units (utilization units), cooling / heating switching units (branch units), and outdoor units (heat source units) are connected to high and low pressure gas connection pipes. There is an air conditioner (cooling and heating simultaneous operation type air conditioner) configured by being connected via a low pressure gas connection pipe and a liquid connection pipe (three refrigerant communication pipes). Here, the utilization unit has an indoor expansion valve (use side expansion valve) and an indoor heat exchanger (use side heat exchanger). The branch unit has a high-pressure side opening / closing mechanism (high-pressure gas control valve) and a low-pressure side opening / closing mechanism (low-pressure gas control valve) corresponding to each utilization unit.

  In this cooling and heating simultaneous operation type air conditioner, a flammable refrigerant is enclosed in a refrigerant circuit, and when leakage of the refrigerant is detected, a utilization side expansion valve and a high-pressure gas corresponding to the utilization unit in which the refrigerant leakage is detected By closing the control valve and opening the low-pressure gas control valve, the refrigerant is recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit.

  Here, when recovering the refrigerant from the usage unit in which the refrigerant leakage is detected to the heat source unit, the refrigerant leakage is detected while continuing the cooling operation and the heating operation in the other usage units in which the refrigerant has not leaked. It is necessary to store the refrigerant sent from the used unit in the heat source unit.

  An object of the present invention is to provide a cooling and heating simultaneous operation type air conditioner configured by connecting a plurality of use units, a branch unit, and a heat source unit via three refrigerant communication pipes. It is to be able to recover the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit while continuing the operation of the utilization unit.

The cooling / heating simultaneous operation type air conditioner according to the first or second aspect includes a plurality of utilization units, a heat source unit, a high-low pressure gas refrigerant communication pipe drawn from the heat source unit, and a low-pressure gas refrigerant communication drawn from the heat source unit. It has a pipe, a liquid refrigerant communication pipe drawn from the heat source unit, and a branch unit. The utilization unit has a utilization side expansion valve and a utilization side heat exchanger. The heat source unit includes a compressor and a plurality of heat source side heat exchangers. The branch unit connects each use unit to a high-low pressure gas refrigerant communication pipe, a low-pressure gas refrigerant communication pipe, and a liquid refrigerant communication pipe, and has a high-pressure gas control valve and a low-pressure gas control valve corresponding to each use unit. Yes. Here, the refrigerant leakage detection means for detecting the refrigerant leakage is provided, the refrigerant adjustment pipe is connected to the heat source unit so as to branch the refrigerant from the liquid side of the heat source side heat exchanger, and the refrigerant is stored in the refrigerant adjustment pipe. And a refrigerant adjustment inlet valve on the inlet side of the refrigerant adjustment container, and when the refrigerant leakage detection means detects refrigerant leakage, the refrigerant adjustment inlet valve is opened to The refrigerant is recovered from the utilization unit in which leakage of the refrigerant is detected to the refrigerant adjustment container of the heat source unit. In the cooling / heating simultaneous operation type air conditioner according to the first aspect, the refrigerant adjustment inlet valve is closed after a predetermined time has elapsed since the refrigerant adjustment inlet valve is opened, and the refrigerant is collected into the refrigerant adjustment container. And the number of heat source side heat exchangers functioning as refrigerant radiators is increased, and the refrigerant is recovered from the utilization unit in which refrigerant leakage is detected to the heat source side heat exchanger of the heat source unit . Further, in the cooling and heating simultaneous operation type air conditioner according to the second aspect, after the refrigerant adjustment container reaches a predetermined liquid level, the refrigerant adjustment inlet valve is closed to finish collecting the refrigerant into the refrigerant adjustment container, and The number of heat source side heat exchangers functioning as a refrigerant radiator is increased, and the refrigerant is recovered from the utilization unit in which refrigerant leakage is detected to the heat source side heat exchanger of the heat source unit.

  Here, the refrigerant recovered to the heat source unit from the utilization unit in which leakage of the refrigerant is detected can be branched from the liquid side of the heat source side heat exchanger by the refrigerant adjustment pipe and stored in the refrigerant adjustment container. Thereby, the refrigerant can be recovered from the utilization unit in which the leakage of the refrigerant is detected to the heat source unit while continuing the cooling operation or the heating operation in the other utilization unit in which the refrigerant has not leaked.

However, when there is a large amount of refrigerant recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit or when the volume of the refrigerant adjustment container is small, the refrigerant adjustment container may not be able to store the refrigerant.

Therefore, in the cooling and heating simultaneous operation type air conditioner according to the first aspect, as described above, after a predetermined time has elapsed since the refrigerant adjustment inlet valve was opened, the refrigerant adjustment inlet valve was closed, and the refrigerant The number of heat source side heat exchangers functioning as heat radiators is increased, and the refrigerant is recovered from the utilization unit in which refrigerant leakage is detected to the heat source side heat exchanger of the heat source unit. Further, in the cooling and heating simultaneous operation type air conditioner according to the second aspect, as described above, after the refrigerant adjustment container reaches the predetermined liquid level, the refrigerant adjustment inlet valve is closed and functions as a refrigerant radiator. The number of heat source side heat exchangers to be increased is increased, and the refrigerant is recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source side heat exchanger of the heat source unit. Thereby, when recovering the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit, the refrigerant that cannot be stored in the refrigerant adjustment container can be stored in the heat source side heat exchanger.

The cooling / heating simultaneous operation type air conditioning apparatus according to the third aspect is the cooling / heating simultaneous operation type air conditioning apparatus according to the first or second aspect, in which the heat source side heat exchanger includes the first heat source side heat exchanger, And a second heat source side heat exchanger having a volume larger than that of the first heat source side heat exchanger, and after a predetermined time has elapsed since the refrigerant adjustment inlet valve was opened, or the refrigerant adjustment container is predetermined After reaching the liquid level, the second heat source side heat exchanger is caused to function as a refrigerant radiator.

  When there is a large amount of refrigerant recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit or when the volume of the refrigerant adjustment container is small, the refrigerant adjustment container may not be able to store the refrigerant.

  Therefore, here, as described above, after a predetermined time has elapsed since the refrigerant adjustment inlet valve was opened, or after the refrigerant adjustment container has reached a predetermined liquid level, the heat source side heat exchanger is radiated of the refrigerant. To function as a container. Thereby, when recovering the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit, the refrigerant that cannot be stored in the refrigerant adjustment container can be stored in the heat source side heat exchanger. In addition, as described above, the second heat source side heat exchanger having a large volume out of the two heat source side heat exchangers is caused to function as a refrigerant radiator, and therefore cannot be stored in the refrigerant adjustment container. Refrigerant can be collected reliably.

The cooling / heating simultaneous operation type air conditioning apparatus according to the fourth aspect is the cooling / heating simultaneous operation type air conditioning apparatus according to the first to third aspects , wherein the low pressure in the utilization unit in which the leakage of the refrigerant is detected becomes a predetermined pressure or less. After that, the recovery of the refrigerant from the utilization unit in which the leakage of the refrigerant is detected to the heat source unit is finished.

  If there is little refrigerant recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit or if the volume of the refrigerant adjustment container is large, before the predetermined time elapses after the refrigerant adjustment inlet valve is opened, or Before the refrigerant adjustment container reaches the predetermined liquid level, there may be no refrigerant to be collected in the heat source unit from the usage unit in which the refrigerant leakage is detected.

Therefore, here, as described above, by Rukoto low pressure, such below a predetermined pressure in the use unit refrigerant leakage is detected, the refrigerant should leak of the refrigerant is recovered to the heat source unit from the utilization unit is detected Recovering the refrigerant can be completed promptly after confirming that it has disappeared.

  As described above, according to the present invention, the following effects can be obtained.

In the cooling and heating simultaneous operation type air conditioner according to the first or second aspect, the heat source from the utilization unit in which the refrigerant leakage is detected while continuing the cooling operation or the heating operation in the other utilization unit in which the refrigerant does not leak. The refrigerant can be recovered in the unit. Moreover, when the refrigerant is recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit, the refrigerant that cannot be stored in the refrigerant adjustment container can be stored in the heat source side heat exchanger.

In the cooling and heating simultaneous operation type air conditioner according to the third aspect , when the refrigerant is recovered from the utilization unit in which the refrigerant leakage is detected to the heat source unit, the refrigerant that cannot be stored in the refrigerant adjustment container is removed from the heat source side heat exchanger. It can be surely collected.

In the cooling and heating simultaneous operation type air conditioner according to the fourth aspect , the refrigerant recovery is promptly terminated after confirming that there is no refrigerant to be recovered in the heat source unit from the use unit in which leakage of the refrigerant is detected. Can do.

It is a schematic block diagram of the cooling-heating simultaneous operation type air conditioning apparatus concerning one Embodiment of this invention. It is the schematic which shows the structure of a refrigerant | coolant adjustment container. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the air_conditionaing | cooling operation (large evaporation load) of a cooling / heating simultaneous operation type air conditioner. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the air_conditionaing | cooling operation (low evaporation load) of a cooling / heating simultaneous operation type air conditioner. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating operation (large heat radiation load) of a cooling / heating simultaneous operation type air conditioner. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating operation (small heat radiation load) of a cooling / heating simultaneous operation type air conditioner. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating / cooling simultaneous operation (evaporation load main body) of a cooling / heating simultaneous operation type air conditioner. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating / cooling simultaneous operation (heat radiation load main body) of the cooling / heating simultaneous operation type air conditioner. It is a flowchart of operation | movement when the leakage of a refrigerant | coolant is detected. It is a figure (at the time of collection to a refrigerant adjustment container) showing operation (flow of a refrigerant) when leakage of a refrigerant is detected at the time of air conditioning operation (radiation load is small). It is a flowchart of operation | movement when the leakage of the refrigerant | coolant in a modification is detected. It is a flowchart of operation | movement when the leakage of the refrigerant | coolant in a modification is detected. It is a figure (at the time of collection to a heat source side heat exchanger) which shows operation (refrigerant flow) when leakage of a refrigerant is detected at the time of cooling operation (small evaporation load) in a modification. It is a figure (at the time of recovery to a heat source side heat exchanger) which shows operation (flow of a refrigerant) when leakage of a refrigerant is detected at the time of heating operation (large heat radiation load) in a modification. It is a figure (at the time of collection to a heat source side heat exchanger) which shows operation (refrigerant flow) when leakage of a refrigerant is detected at the time of heating operation (small heat radiation load) in a modification. It is a figure (at the time of recovery to a heat source side heat exchanger) which shows operation (flow of a refrigerant) when leakage of a refrigerant is detected at the time of simultaneous cooling and heating operation (mainly evaporation load) in a modification. It is a figure (at the time of collection to a heat source side heat exchanger) which shows operation (flow of a refrigerant) when leakage of a refrigerant is detected at the time of cooling and heating simultaneous operation (main part of heat radiation load) in a modification.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a cooling and heating simultaneous operation type air conditioner according to the present invention will be described based on the drawings. The specific configuration of the cooling and heating simultaneous operation type air conditioner according to the present invention is not limited to the following embodiments and modifications thereof, and can be changed without departing from the gist of the invention.

(1) Configuration of Cooling and Heating Simultaneous Operation Type Air Conditioner FIG. 1 is a schematic configuration diagram of a cooling and heating simultaneous operation type air conditioner 1 according to an embodiment of the present invention. FIG. 2 is a schematic view showing the structure of the refrigerant adjustment container 41. The cooling and heating simultaneous operation type air conditioner 1 is an apparatus used for air conditioning in a room such as a building by performing a vapor compression refrigeration cycle operation.

  The cooling and heating simultaneous operation type air conditioner 1 includes a plurality of (here, four) use units 3a, 3b, 3c, 3d, a heat source unit 2 (here, one), and branch units 4a, 4b, 4c, 4d ( Here, four usage units 3a, 3b, 3c, and 3d correspond to three refrigerant communication pipes (liquid refrigerant communication pipe 7, high and low pressure gas refrigerant communication pipe 8, and low pressure gas refrigerant communication pipe 9). It is comprised by connecting via. That is, the vapor compression refrigerant circuit 10 of the cooling and heating simultaneous operation type air conditioner 1 includes a heat source unit 2, utilization units 3a, 3b, 3c, and 3d, branch units 4a, 4b, 4c, and 4d, and a refrigerant communication tube. 7, 8 and 9 are connected to each other. The refrigerant circuit 10 is filled with a refrigerant (flammable refrigerant) that may ignite under a specific condition such as R32. In the cooling / heating simultaneous operation type air conditioner 1, each of the use units 3a, 3b, 3c, and 3d can individually perform the cooling operation or the heating operation, and the cooling operation is performed from the use unit that performs the heating operation. Heat is recovered between the utilization units by sending the refrigerant to the utilization unit to be performed (here, simultaneous cooling / heating operation in which the cooling operation and the heating operation are performed simultaneously) is possible. In addition, in the cooling and heating simultaneous operation type air conditioner 1, the heat load of the heat source unit 2 is changed according to the heat loads of the plurality of utilization units 3a, 3b, 3c, and 3d in consideration of the heat recovery (simultaneous cooling and heating operation). It is configured to balance.

<Usage unit>
The use units 3a, 3b, 3c, and 3d are installed by being embedded or suspended in a ceiling of a room such as a building, or by hanging on a wall surface of the room. The utilization units 3a, 3b, 3c, and 3d are connected to the heat source unit 2 via the refrigerant communication pipes 7, 8, and 9 and the branch units 4a, 4b, 4c, and 4d, and constitute a part of the refrigerant circuit 10. ing.

  Next, the configuration of the usage units 3a, 3b, 3c, and 3d will be described. Since the usage unit 3a and the usage units 3b, 3c, and 3d have the same configuration, only the configuration of the usage unit 3a will be described here, and the configuration of the usage units 3b, 3c, and 3d will be described respectively. Instead of the subscript “a” indicating the respective parts of 3a, the subscript “b”, “c” or “d” is attached, and the description of each part is omitted.

  The usage unit 3a mainly constitutes a part of the refrigerant circuit 10, and includes usage-side refrigerant circuits 13a (in the usage units 3b, 3c, and 3d, usage-side refrigerant circuits 13b, 13c, and 13d, respectively). Yes. The use side refrigerant circuit 13a mainly has a use side expansion valve 51a and a use side heat exchanger 52a.

  The use side expansion valve 51a is an electric expansion valve capable of adjusting the opening degree connected to the liquid side of the use side heat exchanger 52a in order to adjust the flow rate of the refrigerant flowing through the use side heat exchanger 52a. .

  The use-side heat exchanger 52a is a device for performing heat exchange between the refrigerant and the room air, and includes, for example, a fin-and-tube heat exchanger configured by a large number of heat transfer tubes and fins. Here, the utilization unit 3a has an indoor fan 53a for supplying indoor air as supply air after sucking indoor air into the unit and exchanging heat, and the indoor air and utilization side heat exchanger 52a. It is possible to exchange heat with the refrigerant flowing through The indoor fan 53a is driven by the indoor fan motor 54a.

  The utilization unit 3a is provided with various sensors. Specifically, a refrigerant sensor 57a as refrigerant leakage detection means for detecting refrigerant leakage from the usage unit 3a, a liquid side temperature sensor 58a for detecting the temperature of the refrigerant on the liquid side of the usage side heat exchanger 52a, Is provided. In addition, the usage unit 3a includes a usage-side control unit 50a that controls the operations of the units 51a and 54a constituting the usage unit 3a. The use-side control unit 50a includes a microcomputer and a memory provided for controlling the use unit 3a, and exchanges control signals and the like with a remote controller (not shown). Control signals and the like can be exchanged with the heat source unit 2 and the branch unit 4a.

<Heat source unit>
The heat source unit 2 is installed on the rooftop of a building or the like, and is connected to the utilization units 3a, 3b, 3c, 3d via the refrigerant communication tubes 7, 8, 9 and the branch units 4a, 4b, 4c, 4d. And constitutes a part of the refrigerant circuit 10.

  Next, the configuration of the heat source unit 2 will be described. The heat source unit 2 mainly constitutes a part of the refrigerant circuit 10 and has a heat source side refrigerant circuit 12. The heat source side refrigerant circuit 12 mainly includes a compressor 21, a plurality (here, two) heat exchange switching mechanisms 22, 23, and a plurality (here, two) heat source side heat exchangers 24, 25, A plurality of (here, two) heat source side expansion valves 26, 27, a high / low pressure switching mechanism 30, a liquid side closing valve 31, a high / low pressure gas side closing valve 32, a low pressure gas side closing valve 33, A refrigerant adjustment container 41 and refrigerant adjustment pipes 42 and 45 are provided.

  Here, the compressor 21 is a device for compressing the refrigerant, and includes, for example, a scroll type positive displacement compressor capable of changing the operation capacity by inverter-controlling the compressor motor 28.

  When the first heat exchanger switching mechanism 22 causes the first heat source side heat exchanger 24 to function as a refrigerant radiator (hereinafter referred to as “heat dissipation operation state”), the discharge side and the first heat source side of the compressor 21 are used. When the gas side of the heat exchanger 24 is connected (see the solid line of the first heat exchange switching mechanism 22 in FIG. 1) and the first heat source side heat exchanger 24 functions as a refrigerant evaporator (hereinafter referred to as “evaporation”). In the “operating state”, the suction side of the compressor 21 and the gas side of the first heat source side heat exchanger 24 are connected (see the broken line of the first heat exchange switching mechanism 22 in FIG. 1). This is a device capable of switching the refrigerant flow path in the side refrigerant circuit 12, and is composed of, for example, a four-way switching valve. The second heat exchange switching mechanism 23 is connected to the discharge side of the compressor 21 and the second side when the second heat source side heat exchanger 25 functions as a refrigerant radiator (hereinafter referred to as “heat dissipation operation state”). When connecting the gas side of the heat source side heat exchanger 25 (see the solid line of the second heat exchange switching mechanism 23 in FIG. 1), and causing the second heat source side heat exchanger 25 to function as a refrigerant evaporator (hereinafter, referred to as a refrigerant evaporator) In the “evaporation operation state”, the suction side of the compressor 21 and the gas side of the second heat source side heat exchanger 25 are connected (see the broken line of the second heat exchange switching mechanism 23 in FIG. 1). The device is capable of switching the refrigerant flow path in the heat source side refrigerant circuit 12, and is composed of, for example, a four-way switching valve. Then, by changing the switching state of the first heat exchange switching mechanism 22 and the second heat exchange switching mechanism 23, the first heat source side heat exchanger 24 and the second heat source side heat exchanger 25 individually evaporate the refrigerant. Switching to function as a heat sink or a radiator is possible.

  The first heat source side heat exchanger 24 is a device for performing heat exchange between the refrigerant and the outdoor air, and includes, for example, a fin-and-tube heat exchanger constituted by a large number of heat transfer tubes and fins. The gas side of the first heat source side heat exchanger 24 is connected to the first heat exchange switching mechanism 22, and the liquid side thereof is connected to the first heat source side expansion valve 26. The second heat source side heat exchanger 25 is a device for performing heat exchange between the refrigerant and the outdoor air. For example, the second heat source side heat exchanger 25 includes a fin-and-tube heat exchanger constituted by a large number of heat transfer tubes and fins. Become. The gas side of the second heat source side heat exchanger 25 is connected to the second heat exchange switching mechanism 23, and the liquid side thereof is connected to the second heat source side expansion valve 27. Here, the first heat source side heat exchanger 24 and the second heat source side heat exchanger 25 are configured as an integral heat source side heat exchanger. Here, the volume of the second heat source side heat exchanger 25 (the volume of the flow path through which the refrigerant flows) is larger than the volume of the first heat source side heat exchanger 24. The heat source unit 2 has an outdoor fan 34 for sucking outdoor air into the unit, exchanging heat, and then discharging the air outside the unit. The outdoor air and the heat source side heat exchangers 24 and 25 are connected to the heat source unit 2. It is possible to exchange heat with the flowing refrigerant. The outdoor fan 34 is driven by an outdoor fan motor 29 capable of controlling the rotational speed.

  The first heat source side expansion valve 26 can adjust the opening degree connected to the liquid side of the first heat source side heat exchanger 24 in order to adjust the flow rate of the refrigerant flowing through the first heat source side heat exchanger 24. This is an electric expansion valve. Further, the second heat source side expansion valve 27 adjusts the opening degree connected to the liquid side of the second heat source side heat exchanger 25 in order to adjust the flow rate of the refrigerant flowing through the second heat source side heat exchanger 25. This is an electric expansion valve capable of

  The high / low pressure switching mechanism 30, when sending the high-pressure gas refrigerant discharged from the compressor 21 to the use-side refrigerant circuits 13 a, 13 b, 13 c, and 13 d (hereinafter referred to as “heat dissipation load operation state”), 21 is connected to the high-low pressure gas side shut-off valve 32 (see the broken line of the high-low pressure switching mechanism 30 in FIG. 1), and the high-pressure gas refrigerant discharged from the compressor 21 is used on the use-side refrigerant circuits 13a, 13b. , 13c, 13d (hereinafter referred to as “evaporative load operation state”), the high / low pressure gas side shut-off valve 32 and the suction side of the compressor 21 are connected (high / low pressure switching in FIG. 1). (Refer to the solid line of the mechanism 30), which is a device capable of switching the refrigerant flow path in the heat source side refrigerant circuit 12, and includes, for example, a four-way switching valve.

  The liquid side shut-off valve 31, the high-low pressure gas side shut-off valve 32, and the low-pressure gas side shut-off valve 33 are provided at the connection ports with external devices and piping (specifically, the refrigerant communication pipes 7, 8, and 9). It is a valve. That is, the liquid side closing valve 31 is connected to the liquid refrigerant communication pipe 7 drawn out from the heat source unit 2, and the high / low pressure gas side closing valve 32 is connected to the high / low pressure gas refrigerant connecting pipe 8 drawn out from the heat source unit 2. The low-pressure gas side shut-off valve 33 is connected to the low-pressure gas refrigerant communication pipe 9 drawn from the heat source unit 2.

  The refrigerant adjustment tubes 42 and 45 have a first refrigerant adjustment tube 42 and a second refrigerant adjustment tube 45. One end of the first refrigerant adjustment pipe 42 is connected to the heat source side refrigerant circuit 12 so that the refrigerant branches from the liquid side of the heat source side heat exchangers 24 and 25, and the other end is connected to the inlet of the refrigerant adjustment container 41. It is connected. One end of the second refrigerant adjustment pipe 45 is connected to the outlet of the refrigerant adjustment container 41, and the other end is connected to the heat source side refrigerant circuit 12 so as to join the suction side of the compressor 21. In the refrigerant adjustment pipes 42 and 45, the inlet side of the refrigerant adjustment container 41, that is, the first refrigerant adjustment pipe 42 is provided with a refrigerant adjustment inlet valve 43 that can be opened and closed. The second refrigerant adjustment pipe 45 is provided with a refrigerant adjustment outlet valve 46 that can be opened and closed. Here, although the solenoid valve is employ | adopted as the refrigerant | coolant adjustment inlet valve 43 and the refrigerant | coolant adjustment outlet valve 46, you may employ | adopt the electric expansion valve which can adjust an opening degree. Further, the first refrigerant adjustment pipe 42 is provided with an inlet check valve 44 that allows only the flow of refrigerant from the liquid side of the heat source side heat exchangers 24 and 25 toward the refrigerant adjustment container 41. The second refrigerant adjustment pipe 45 is provided with an outlet capillary tube 47 for reducing the pressure of the refrigerant flowing through the second refrigerant adjustment pipe 45 and limiting the flow rate.

  The refrigerant adjustment container 41 is a container that can store the refrigerant, and is connected to the heat source side refrigerant circuit 12 via the refrigerant adjustment pipes 42 and 45. The first refrigerant adjustment pipe 42 is connected so that the refrigerant flows from the upper part of the refrigerant adjustment container 41, and the second refrigerant adjustment pipe 45 is connected so that the refrigerant flows out from the lower part of the refrigerant adjustment container 41. Yes. In addition, one end of a liquid level detection tube 48 is connected to the refrigerant adjustment container 41 so that the refrigerant flows out from the position of the predetermined liquid level L1 near the full liquid. The other end of the liquid level detection pipe 48 is connected so as to join the middle part of the second refrigerant adjustment pipe 45. The liquid level detection tube 48 is provided with a liquid level detection valve 49 that can be opened and closed. Here, an electromagnetic valve is employed as the liquid level detection valve 49, but an electric expansion valve capable of adjusting the opening degree may be employed.

  The heat source unit 2 is provided with various sensors. Specifically, the suction pressure sensor 38 for detecting the pressure of the refrigerant on the suction side of the compressor 21, the discharge pressure sensor 39 for detecting the pressure of the refrigerant on the discharge side of the compressor 21, and the discharge side of the compressor 21 A discharge temperature sensor 40 that detects the temperature of the refrigerant is provided. Further, the heat source unit 2 includes a heat source side control unit 20 that controls the operations of the units 22, 23, 26, 27, 28, 29, 30, 43, 46, and 49 that constitute the heat source unit 2. The heat source side control unit 20 includes a microcomputer and a memory provided to control the heat source unit 2, and uses side control units 50a, 50b, 50c of the usage units 3a, 3b, 3c, 3d. , 50d can exchange control signals and the like.

<Branch unit>
The branch units 4a, 4b, 4c, and 4d are installed together with the use units 3a, 3b, 3c, and 3d in a room such as a building. The branch units 4a, 4b, 4c, and 4d are interposed between the utilization units 3a, 3b, 3c, and 3d and the heat source unit 2 together with the refrigerant communication tubes 7, 8, and 9, and a part of the refrigerant circuit 10 is provided. It is composed.

  Next, the structure of branch unit 4a, 4b, 4c, 4d is demonstrated. Since the branch unit 4a and the branch units 4b, 4c, and 4d have the same configuration, only the configuration of the branch unit 4a will be described here, and the configuration of the branch units 4b, 4c, and 4d will be described respectively. In place of the subscript “a” indicating the respective parts of 4a, the subscript “b”, “c” or “d” is attached, and the description of each part is omitted.

  The branch unit 4a mainly constitutes a part of the refrigerant circuit 10, and includes a branch side refrigerant circuit 14a (the branch side refrigerant circuits 14b, 14c, and 14d in the branch units 4b, 4c, and 4d, respectively). Yes. The branch side refrigerant circuit 14a mainly has a liquid connection pipe 61a and a gas connection pipe 62a.

  One end of the liquid connection pipe 61a is connected to the use side expansion valve 51a of the use unit 3a. The other end of the liquid refrigerant pipe 61 a is connected to the liquid refrigerant communication pipe 7.

  The gas connection pipe 62a includes a high-pressure gas connection pipe 63a, a low-pressure gas connection pipe 64a, and a merged gas connection pipe 65a that joins the high-pressure gas connection pipe 63a and the low-pressure gas connection pipe 64a.

  One end of the high-pressure gas connection pipe 63a is connected to the merged gas connection pipe 65a. The other end of the high-pressure gas connection pipe 63a is connected to the high-low pressure gas refrigerant communication pipe 8. The high-pressure gas connection pipe 63a is provided with a high-pressure gas control valve 66a that can be opened and closed. Here, as the high-pressure gas control valve 66a, an electric expansion valve capable of adjusting the opening degree is employed, but an electromagnetic valve or the like that can only be opened and closed may be employed.

  One end of the low-pressure gas connection pipe 64a is connected to the merged gas connection pipe 65a. The other end of the low-pressure gas connection pipe 64 a is connected to the low-pressure gas refrigerant communication pipe 9. The low-pressure gas connection pipe 64a is provided with a low-pressure gas control valve 67a that can be opened and closed. Here, as the low-pressure gas control valve 67a, an electric expansion valve capable of adjusting the opening degree is employed, but an electromagnetic valve or the like that can only be opened and closed may be employed.

  One end of the combined gas connection pipe 65a is connected to the gas side of the use side heat exchanger 52a of the use unit 3a. The other end of the combined gas connection pipe 65a is connected to the high pressure gas connection pipe 63a and the low pressure gas connection pipe 64a.

  When the use unit 3a performs the cooling operation, the branch unit 4a opens the low-pressure gas control valve 67a and causes the refrigerant flowing into the liquid connection pipe 61a through the liquid refrigerant communication pipe 7 to expand on the use side. Through the valve 51a, the refrigerant that has been sent to the use side heat exchanger 52a of the use unit 3a and evaporated by heat exchange with the indoor air in the use side heat exchanger 52a is converted into the combined gas connection pipe 65a, the low pressure gas control valve 67a, and the low pressure gas. It can function to return to the low-pressure gas refrigerant communication pipe 9 through the connection pipe 64a. Further, the branching unit 4a closes the low-pressure gas control valve 67a and opens the high-pressure gas control valve 66a when the use unit 3a performs the heating operation, and passes through the high-low pressure gas refrigerant communication pipe 8. The refrigerant flowing into the high pressure gas connection pipe 63a is sent to the use side heat exchanger 52a of the use unit 3a through the high pressure gas control valve 66a and the merged gas connection pipe 65a, and heat exchange with room air is performed in the use side heat exchanger 52a. It is possible to function so that the refrigerant that has dissipated the heat returns to the liquid refrigerant communication pipe 7 through the use side expansion valve 51a and the liquid connection pipe 61a. Since such a function has not only the branch unit 4a but also the branch units 4b, 4c, and 4d, the use side heat exchangers 52a, 52b, 52c, and 52d are connected to the branch units 4a, 4b, 4c. 4d enables switching to individually function as a refrigerant evaporator or radiator.

  Further, the branch unit 4a includes a branch-side control unit 60a that controls the operations of the units 66a and 67a constituting the branch unit 4a. The branch side control unit 60a includes a microcomputer and a memory provided to control the branch unit 60a, and exchanges control signals and the like with the use side control unit 50a of the use unit 3a. Can be done.

  As described above, the cooling and heating simultaneous operation type air conditioner 1 includes the plurality of (here, four) use units 3a, 3b, 3c, and 3d, the heat source unit 2, and the high and low pressure gas refrigerant drawn from the heat source unit 2. It has a communication pipe 8, a low-pressure gas refrigerant communication pipe 9 drawn from the heat source unit 2, a liquid refrigerant communication pipe 7 drawn from the heat source unit 2, and branch units 4a, 4b, 4c and 4d. Here, utilization unit 3a, 3b, 3c, 3d has utilization side expansion valve 51a, 51b, 51c, 51d and utilization side heat exchanger 52a, 52b, 52c, 52d. The heat source unit 2 includes a compressor 21 and heat source side heat exchangers 24 and 25. The branch units 4a, 4b, 4c, and 4d connect the usage units 3a, 3b, 3c, and 3d to the high / low pressure gas refrigerant communication pipe 8, the low pressure gas refrigerant communication pipe 9, and the liquid refrigerant communication pipe 7, respectively. High pressure gas control valves 66a, 66b, 66c, 66d and low pressure gas control valves 67a, 67b, 67c, 67d corresponding to the units 3a, 3b, 3c, 3d are provided. Here, refrigerant sensors 57a, 57b, 57c and 57d are provided as refrigerant leakage detection means for detecting refrigerant leakage, and the refrigerant is branched from the liquid side of the heat source side heat exchangers 24 and 25 to the heat source unit 2. The adjustment pipes 42 and 45 are connected, and the refrigerant adjustment pipes 41 and 45 are provided with a refrigerant adjustment container 41 capable of storing the refrigerant, and a refrigerant adjustment inlet valve 43 is provided on the inlet side of the refrigerant adjustment container 41.

(2) Operation of Cooling and Heating Simultaneous Operation Type Air Conditioner Next, the operation of the cooling and heating simultaneous operation type air conditioner 1 will be described with reference to FIGS.

  The refrigeration cycle operation of the cooling / heating simultaneous operation type air conditioner 1 can be mainly divided into a cooling operation, a heating operation, a cooling / heating simultaneous operation (evaporation load main body), and a cooling / heating simultaneous operation (heat radiation load main body). Here, in the cooling operation, there is only a use unit that performs a cooling operation (that is, an operation in which the use-side heat exchanger functions as an evaporator of the refrigerant), and the heat source-side heat exchanger with respect to the evaporation load of the entire use unit This is a refrigeration cycle operation in which 24 and 25 function as a refrigerant radiator. In the heating operation, there are only use units that perform the heating operation (that is, the operation in which the use-side heat exchanger functions as a refrigerant radiator), and the heat source-side heat exchangers 24 and 25 with respect to the heat radiation load of the entire use unit. Is a refrigeration cycle operation that functions as a refrigerant evaporator. Simultaneous cooling and heating operation (evaporation load mainly) is a cooling unit (that is, an operation in which the use side heat exchanger functions as a refrigerant evaporator) and a heating unit (ie, the use side heat exchanger is a refrigerant radiator). Use units that perform the operation that functions as a mixture), and the heat load of the entire use unit is mainly the evaporation load, the heat source side heat exchangers 24 and 25 are connected to the evaporation load of the entire use unit. This is a refrigeration cycle operation that functions as a radiator. Simultaneous cooling and heating operation (mainly heat radiation load) is a cooling unit (that is, an operation in which the use side heat exchanger functions as a refrigerant evaporator) and a heating unit (that is, the use side heat exchanger is a refrigerant radiator). When the heat load of the entire utilization unit is mainly the heat radiation load, the heat source side heat exchangers 24 and 25 are connected to the heat radiation load of the entire utilization unit. This is a refrigeration cycle operation that functions as an evaporator.

  The operation of the cooling / heating simultaneous operation type air conditioner 1 including these refrigeration cycle operations is performed by the control units 20, 50a, 50b, 50c, 50d, 60a, 60b, 60c, and 60d.

<Cooling operation>
During the cooling operation, for example, all of the usage units 3a, 3b, 3c, and 3d perform a cooling operation (that is, an operation in which all of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant evaporator). When both of the heat source side heat exchangers 24 and 25 function as a refrigerant radiator, the refrigerant circuit 10 of the air conditioner 1 is configured as shown in FIG. 3 (for the refrigerant flow, see FIG. 3). (Refer to the arrow attached to the refrigerant circuit 10).

  Specifically, in the heat source unit 2, the first heat exchange switching mechanism 22 is switched to the heat radiation operation state (the state indicated by the solid line of the first heat exchange switching mechanism 22 in FIG. 3), and the second heat exchange switching mechanism 22 23 is switched to the heat radiation operation state (the state indicated by the solid line of the second heat exchange switching mechanism 23 in FIG. 3), so that both the heat source side heat exchangers 24 and 25 function as a refrigerant radiator. ing. Further, the high / low pressure switching mechanism 30 is switched to the evaporative load operation state (the state indicated by the solid line of the high / low pressure switching mechanism 30 in FIG. 3). Moreover, the opening degree of the heat source side expansion valves 26 and 27 is adjusted. Further, by closing the refrigerant adjustment inlet valve 43, the refrigerant adjustment outlet valve 46, and the liquid level detection valve 49, the refrigerant is not exchanged between the heat source side refrigerant circuit 12 and the refrigerant adjustment container 41. . In the branch units 4a, 4b, 4c and 4d, the use units 3a, 3b are opened by opening the high pressure gas control valves 66a, 66b, 66c, 66d and the low pressure gas control valves 67a, 67b, 67c, 67d. 3c, 3d use side heat exchangers 52a, 52b, 52c, 52d all function as refrigerant evaporators, and use units 3a, 3b, 3c, 3d use side heat exchangers 52a, 52b, 52c, All of 52d and the suction side of the compressor 21 of the heat source unit 2 are connected via the high and low pressure gas refrigerant communication pipe 8 and the low pressure gas refrigerant communication pipe 9. In the usage units 3a, 3b, 3c, and 3d, the opening degrees of the usage-side expansion valves 51a, 51b, 51c, and 51d are adjusted.

  In such a refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to both the heat source side heat exchangers 24 and 25 through the heat exchange switching mechanisms 22 and 23. The high-pressure gas refrigerant sent to the heat source side heat exchangers 24 and 25 dissipates heat by exchanging heat with outdoor air as a heat source supplied by the outdoor fan 34 in the heat source side heat exchangers 24 and 25. The refrigerant that has radiated heat in the heat source side heat exchangers 24, 25 is sent to the liquid refrigerant communication tube 7 through the liquid side closing valve 31 after the flow rate is adjusted in the heat source side expansion valves 26, 27.

  The refrigerant sent to the liquid refrigerant communication tube 7 is branched into four and sent to the liquid connection tubes 61a, 61b, 61c, 61d of the branch units 4a, 4b, 4c, 4d. The refrigerant sent to the liquid connection pipes 61a, 61b, 61c, 61d is sent to the use side expansion valves 51a, 51b, 51c, 51d of the use units 3a, 3b, 3c, 3d.

  The refrigerant sent to the use side expansion valves 51a, 51b, 51c, 51d is adjusted in flow rate at the use side expansion valves 51a, 51b, 51c, 51d and then used on the use side heat exchangers 52a, 52b, 52c, 52d. In the above, the heat is exchanged with the indoor air supplied by the indoor fans 53a, 53b, 53c, 53d to evaporate into a low-pressure gas refrigerant. On the other hand, the room air is cooled and supplied to the room, and the use units 3a, 3b, 3c, and 3d are cooled. The low-pressure gas refrigerant evaporated in the use side heat exchangers 52a, 52b, 52c, 52d is sent to the merged gas connection pipes 65a, 65b, 65c, 65d of the branch units 4a, 4b, 4c, 4d.

  The low-pressure gas refrigerant sent to the merged gas connection pipes 65a, 65b, 65c, 65d passes through the high-pressure gas control valves 66a, 66b, 66c, 66d and the high-pressure gas connection pipes 63a, 63b, 63c, 63d. It is sent to the gas refrigerant communication pipe 8 and merges, and is sent to the low pressure gas refrigerant communication pipe 9 through the low pressure gas control valves 67a, 67b, 67c and 67d and the low pressure gas connection pipes 64a, 64b, 64c and 64d.

  Then, the low-pressure gas refrigerant sent to the gas refrigerant communication pipes 8 and 9 is returned to the suction side of the compressor 21 through the gas-side stop valves 32 and 33 and the high-low pressure switching mechanism 30.

  In this way, the operation in the cooling operation is performed. In addition, some of the usage units 3a, 3b, 3c, and 3d perform a cooling operation (that is, an operation in which some of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant evaporator). When the evaporation load of the entire use side heat exchangers 52a, 52b, 52c, 52d is small, an operation is performed in which only one of the heat source side heat exchangers 24, 25 functions as a refrigerant radiator. For example, as shown in FIG. 4, only the usage units 3a, 3b, and 3c are in the cooling operation (that is, only the usage-side heat exchangers 52a, 52b, and 52c are made of the refrigerant by closing the usage-side expansion valve 52d. When the evaporation load of the entire use side heat exchangers 52a, 52b, 52c, 52d is reduced by performing the operation that functions as an evaporator), by closing the second heat source side expansion valve 27, An operation is performed in which only the first heat source side heat exchanger 24 functions as a refrigerant radiator.

<Heating operation>
In the heating operation, for example, all of the usage units 3a, 3b, 3c, and 3d perform the heating operation (that is, the operation in which all of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant radiator). When both of the heat source side heat exchangers 24 and 25 function as a refrigerant evaporator, the refrigerant circuit 10 of the cooling and heating simultaneous operation type air conditioner 1 is configured as shown in FIG. (See the arrow attached to the refrigerant circuit 10 in FIG. 5).

  Specifically, in the heat source unit 2, the first heat exchange switching mechanism 22 is switched to the evaporation operation state (the state indicated by the broken line of the first heat exchange switching mechanism 22 in FIG. 5), and the second heat exchange switching mechanism is selected. 23 is switched to the evaporation operation state (the state indicated by the broken line of the second heat exchange switching mechanism 23 in FIG. 5), both the heat source side heat exchangers 24 and 25 function as the refrigerant evaporator. ing. Further, the high / low pressure switching mechanism 30 is switched to the heat radiation load operation state (the state indicated by the broken line of the high / low pressure switching mechanism 30 in FIG. 5). Moreover, the opening degree of the heat source side expansion valves 26 and 27 is adjusted. Further, by closing the refrigerant adjustment inlet valve 43, the refrigerant adjustment outlet valve 46, and the liquid level detection valve 49, the refrigerant is not exchanged between the heat source side refrigerant circuit 12 and the refrigerant adjustment container 41. . In the branch units 4a, 4b, 4c, and 4d, the high pressure gas control valves 66a, 66b, 66c, and 66d are opened, and the low pressure gas control valves 67a, 67b, 67c, and 67d are closed, thereby using the use unit 3a. 3b, 3c, 3d use side heat exchangers 52a, 52b, 52c, 52d all function as refrigerant radiators, and use units 3a, 3b, 3c, 3d use side heat exchangers 52a, 52b, All of 52c and 52d and the discharge side of the compressor 21 of the heat source unit 2 are connected via the high and low pressure gas refrigerant communication pipe 8. In the usage units 3a, 3b, 3c, and 3d, the opening degrees of the usage-side expansion valves 51a, 51b, 51c, and 51d are adjusted.

  In such a refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to the high / low pressure gas refrigerant communication pipe 8 through the high / low pressure switching mechanism 30 and the high / low pressure gas side closing valve 32.

  The high-pressure gas refrigerant sent to the high-low pressure gas refrigerant communication pipe 8 is branched into four and sent to the high-pressure gas connection pipes 63a, 63b, 63c, 63d of the branch units 4a, 4b, 4c, 4d. It is done. The high-pressure gas refrigerant sent to the high-pressure gas connection pipes 63a, 63b, 63c, and 63d passes through the high-pressure gas control valves 66a, 66b, 66c, and 66d and the combined gas connection pipes 65a, 65b, 65c, and 65d. It is sent to the use side heat exchangers 52a, 52b, 52c, 52d of 3b, 3c, 3d.

  The high-pressure gas refrigerant sent to the use side heat exchangers 52a, 52b, 52c, and 52d is supplied by the indoor fans 53a, 53b, 53c, and 53d in the use side heat exchangers 52a, 52b, 52c, and 52d. Heat is dissipated by exchanging heat with indoor air. On the other hand, indoor air is heated and supplied indoors, and heating operation of utilization unit 3a, 3b, 3c, 3d is performed. The refrigerant radiated in the use side heat exchangers 52a, 52b, 52c, 52d is adjusted in flow rate in the use side expansion valves 51a, 51b, 51c, 51d, and then the liquid connection pipe 61a of the branch units 4a, 4b, 4c, 4d. , 61b, 61c, 61d.

  Then, the refrigerant sent to the liquid connection pipes 61a, 61b, 61c, 61d is sent to the liquid refrigerant communication pipe 7 and merges.

  Then, the refrigerant sent to the liquid refrigerant communication tube 7 is sent to both the heat source side expansion valves 26 and 27 through the liquid side closing valve 31. The refrigerant sent to the heat source side expansion valves 26 and 27 is subjected to heat exchange with the outdoor air supplied by the outdoor fan 34 in the heat source side heat exchangers 24 and 25 after the flow rate is adjusted in the heat source side expansion valves 26 and 27. Is evaporated to become a low-pressure gas refrigerant and sent to the heat exchange switching mechanisms 22 and 23. The low-pressure gas refrigerant sent to the heat exchange switching mechanisms 22 and 23 merges and is returned to the suction side of the compressor 21.

  In this way, the operation in the heating operation is performed. In addition, some of the usage units 3a, 3b, 3c, and 3d perform a heating operation (that is, an operation in which some of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant radiator). When the heat radiation load of the entire use side heat exchangers 52a, 52b, 52c, 52d becomes small, an operation is performed in which only one of the heat source side heat exchangers 24, 25 functions as a refrigerant evaporator. For example, as shown in FIG. 6, only the usage units 3a, 3b, and 3c are in the heating operation (that is, only the usage-side heat exchangers 52a, 52b, and 52c are made of refrigerant by closing the usage-side expansion valve 52d. When the heat radiation load of the entire use side heat exchangers 52a, 52b, 52c, 52d is reduced by performing the operation functioning as a radiator, by closing the second heat source side expansion valve 27, An operation is performed in which only the first heat source side heat exchanger 24 functions as a refrigerant evaporator.

<Simultaneous cooling and heating operation (mainly evaporation load)>
In simultaneous cooling and heating operation (evaporation load main), for example, the use units 3a, 3b, and 3c are in cooling operation, and the use unit 3d is in heating operation (that is, the use side heat exchangers 52a, 52b, and 52c are refrigerant evaporators And the use side heat exchanger 52d functions as a refrigerant radiator), and only the first heat source side heat exchanger 24 functions as a refrigerant radiator. The refrigerant circuit 10 of the apparatus 1 is configured as shown in FIG. 7 (refer to the arrows attached to the refrigerant circuit 10 in FIG. 7 for the refrigerant flow).

  Specifically, in the heat source unit 2, the first heat exchange switching mechanism 22 is switched to the heat radiation operation state (the state indicated by the solid line of the first heat exchange switching mechanism 22 in FIG. 7), thereby Only the heat exchanger 24 is made to function as a refrigerant radiator. Further, the high / low pressure switching mechanism 30 is switched to the heat radiation load operating state (the state indicated by the broken line of the high / low pressure switching mechanism 30 in FIG. 7). The opening degree of the first heat source side expansion valve 26 is adjusted, and the second heat source side expansion valve 27 is in a closed state. Further, by closing the refrigerant adjustment inlet valve 43, the refrigerant adjustment outlet valve 46, and the liquid level detection valve 49, the refrigerant is not exchanged between the heat source side refrigerant circuit 12 and the refrigerant adjustment container 41. . In the branch units 4a, 4b, 4c, and 4d, the high-pressure gas control valve 66d and the low-pressure gas control valves 67a, 67b, and 67c are opened, and the high-pressure gas control valves 66a, 66b, 66c, and the low-pressure gas By closing the control valve 67d, the use side heat exchangers 52a, 52b, 52c of the use units 3a, 3b, 3c function as a refrigerant evaporator, and the use side heat exchanger 52d of the use unit 3d. Through the low-pressure gas refrigerant communication pipe 9 between the utilization side heat exchangers 52a, 52b, 52c of the utilization units 3a, 3b, 3c and the suction side of the compressor 21 of the heat source unit 2. The use side heat exchanger 52d of the use unit 3d and the discharge side of the compressor 21 of the heat source unit 2 are connected to the high / low pressure gas refrigerant communication pipe 8 in a connected state. To have become the connected state. In the usage units 3a, 3b, 3c, and 3d, the opening degrees of the usage-side expansion valves 51a, 51b, 51c, and 51d are adjusted.

  In such a refrigerant circuit 10, a part of the high-pressure gas refrigerant compressed and discharged by the compressor 21 passes through the high / low pressure switching mechanism 30 and the high / low pressure gas side shut-off valve 32. The remainder is sent to the first heat source side heat exchanger 24 through the first heat exchange switching mechanism 22.

  Then, the high-pressure gas refrigerant sent to the high-low pressure gas refrigerant communication pipe 8 is sent to the high-pressure gas connection pipe 63d of the branch unit 4d. The high-pressure gas refrigerant sent to the high-pressure gas connection pipe 63d is sent to the use-side heat exchanger 52d of the use unit 3d through the high-pressure gas control valve 66d and the merged gas connection pipe 65d.

  The high-pressure gas refrigerant sent to the use side heat exchanger 52d dissipates heat by exchanging heat with the indoor air supplied by the indoor fan 53d in the use side heat exchanger 52d. On the other hand, the indoor air is heated and supplied indoors, and the heating operation of the utilization unit 3d is performed. The refrigerant that has dissipated heat in the use side heat exchanger 52d is sent to the liquid connection pipe 61d of the branch unit 4d after the flow rate is adjusted in the use side expansion valve 51d.

  Then, the refrigerant sent to the liquid connection pipe 61 d is sent to the liquid refrigerant communication pipe 7.

  The high-pressure gas refrigerant sent to the first heat source side heat exchanger 24 dissipates heat by exchanging heat with outdoor air as a heat source supplied by the outdoor fan 34 in the first heat source side heat exchanger 24. To do. The refrigerant radiated in the first heat source side heat exchanger 24 is adjusted in flow rate in the first heat source side expansion valve 26 and then sent to the liquid refrigerant communication pipe 7 through the liquid side closing valve 31 to be used on the use side heat exchanger. In 52d, it merges with the radiated refrigerant.

  And the refrigerant | coolant merged in the liquid refrigerant communication pipe | tube 7 is branched into three, and is sent to the liquid connection pipes 61a, 61b, 61c of each branch unit 4a, 4b, 4c. The refrigerant sent to the liquid connection pipes 61a, 61b, 61c is sent to the use side expansion valves 51a, 51b, 51c of the use units 3a, 3b, 3c.

  The refrigerant sent to the use side expansion valves 51a, 51b, 51c is adjusted in flow rate in the use side expansion valves 51a, 51b, 51c, and then in the use side heat exchangers 52a, 52b, 52c, the indoor fans 53a, By exchanging heat with the indoor air supplied by 53b and 53c, it evaporates and becomes a low-pressure gas refrigerant. On the other hand, the room air is cooled and supplied to the room, and the use units 3a, 3b, and 3c are cooled. The low-pressure gas refrigerant evaporated in the use side heat exchangers 52a, 52b, 52c is sent to the merged gas connection pipes 65a, 65b, 65c of the branch units 4a, 4b, 4c.

  The low-pressure gas refrigerant sent to the merged gas connection pipes 65a, 65b and 65c is sent to the low-pressure gas refrigerant communication pipe 9 through the low-pressure gas control valves 67a, 67b and 67c and the low-pressure gas connection pipes 64a, 64b and 64c. Be merged.

  The low-pressure gas refrigerant sent to the low-pressure gas refrigerant communication pipe 9 is returned to the suction side of the compressor 21 through the low-pressure gas side shut-off valve 33.

  Thus, the operation in the simultaneous cooling and heating operation (evaporation load main body) is performed. Note that the evaporation load of the entire use side heat exchangers 52a, 52b, 52c, and 52d is reduced due to a decrease in the number of use units (that is, use side heat exchangers functioning as refrigerant evaporators) that perform the cooling operation. In this case, by causing the second heat source side heat exchanger 25 to function as a refrigerant evaporator, the heat radiation load of the first heat source side heat exchanger 24 and the evaporation load of the second heat source side heat exchanger 25 are reduced. The operation of canceling and reducing the heat radiation load of the heat source side heat exchangers 24 and 25 as a whole is performed.

<Simultaneous cooling and heating operation (heat dissipation load mainly)>
In simultaneous cooling / heating operation (mainly heat radiation load), for example, the usage units 3a, 3b, 3c are heating operation, and the usage unit 3d is cooling operation (that is, the usage side heat exchangers 52a, 52b, 52c are refrigerant radiators). When the heat-source-side heat exchangers 24 and 25 both function as refrigerant evaporators, the use-side heat exchanger 52d functions as a refrigerant evaporator. The refrigerant circuit 10 of the harmony device 1 is configured as shown in FIG. 8 (refer to the arrows attached to the refrigerant circuit 10 in FIG. 8 for the refrigerant flow).

  Specifically, in the heat source unit 2, the first heat exchange switching mechanism 22 is switched to the evaporation operation state (the state indicated by the broken line of the first heat exchange switching mechanism 22 in FIG. 8), and the second heat exchange switching mechanism is selected. By switching 23 to the evaporation operation state (the state indicated by the broken line of the second heat exchange switching mechanism 23 in FIG. 8), both the heat source side heat exchangers 24 and 25 function as a refrigerant evaporator. ing. Further, the high / low pressure switching mechanism 30 is switched to the heat radiation load operation state (the state indicated by the broken line of the high / low pressure switching mechanism 30 in FIG. 8). Moreover, the opening degree of the heat source side expansion valves 26 and 27 is adjusted. Further, by closing the refrigerant adjustment inlet valve 43, the refrigerant adjustment outlet valve 46, and the liquid level detection valve 49, the refrigerant is not exchanged between the heat source side refrigerant circuit 12 and the refrigerant adjustment container 41. . In the branch units 4a, 4b, 4c, and 4d, the high-pressure gas control valves 66a, 66b, 66c, and the low-pressure gas control valve 67d are opened, and the high-pressure gas control valve 66d and the low-pressure gas control valve 67a are opened. By closing 67b and 67c, the utilization side heat exchangers 52a, 52b and 52c of the utilization units 3a, 3b and 3c function as refrigerant radiators, and the utilization side heat exchanger 52d of the utilization unit 3d. As a refrigerant evaporator, the utilization side heat exchanger 52d of the utilization unit 3d and the suction side of the compressor 21 of the heat source unit 2 are connected via the low-pressure gas refrigerant communication pipe 9, and The use side heat exchangers 52a, 52b, 52c of the use units 3a, 3b, 3c and the discharge side of the compressor 21 of the heat source unit 2 connect the high / low pressure gas refrigerant communication pipe 8. To have become the connected state. In the usage units 3a, 3b, 3c, and 3d, the opening degrees of the usage-side expansion valves 51a, 51b, 51c, and 51d are adjusted.

  In such a refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to the high / low pressure gas refrigerant communication pipe 8 through the high / low pressure switching mechanism 30 and the high / low pressure gas side closing valve 32.

  Then, the high-pressure gas refrigerant sent to the high-low pressure gas refrigerant communication pipe 8 is branched into three and sent to the high-pressure gas connection pipes 63a, 63b, 63c of the branch units 4a, 4b, 4c. The high-pressure gas refrigerant sent to the high-pressure gas connection pipes 63a, 63b, 63c passes through the high-pressure gas control valves 66a, 66b, 66c and the merged gas connection pipes 65a, 65b, 65c to the usage side of the usage units 3a, 3b, 3c. It is sent to the heat exchangers 52a, 52b, 52c.

  The high-pressure gas refrigerant sent to the use side heat exchangers 52a, 52b, 52c exchanges heat with the indoor air supplied by the indoor fans 53a, 53b, 53c in the use side heat exchangers 52a, 52b, 52c. To dissipate heat. On the other hand, room air is heated and supplied indoors, and heating operation of utilization unit 3a, 3b, 3c is performed. The refrigerant that has radiated heat in the use side heat exchangers 52a, 52b, 52c is adjusted in flow rate in the use side expansion valves 51a, 51b, 51c, and then sent to the liquid connection pipes 61a, 61b, 61c of the branch units 4a, 4b, 4c. It is done.

  The refrigerant sent to the liquid connection pipes 61a, 61b, 61c is sent to the liquid refrigerant communication pipe 7 and merges.

  A part of the refrigerant sent to the liquid refrigerant communication pipe 7 is sent to the liquid connection pipe 61d of the branching unit 4d, and the rest passes through the liquid side shut-off valve 31 to both the heat source side expansion valves 26 and 27. Sent to.

  Then, the refrigerant sent to the liquid connection pipe 61d is sent to the use side expansion valve 51d of the use unit 3d.

  The refrigerant sent to the use side expansion valve 51d is subjected to heat exchange with indoor air supplied by the indoor fan 53d in the use side heat exchanger 52d after the flow rate is adjusted in the use side expansion valve 51d. Evaporates into a low-pressure gas refrigerant. On the other hand, the indoor air is cooled and supplied to the room, and the cooling operation of the utilization unit 3d is performed. The low-pressure gas refrigerant evaporated in the use side heat exchanger 52d is sent to the merged gas connection pipe 65d of the branch unit 4d.

  The low-pressure gas refrigerant sent to the merged gas connection pipe 65d is sent to the low-pressure gas refrigerant communication pipe 9 through the low-pressure gas control valve 67d and the low-pressure gas connection pipe 64d.

  The low-pressure gas refrigerant sent to the low-pressure gas refrigerant communication pipe 9 is returned to the suction side of the compressor 21 through the low-pressure gas side shut-off valve 33.

  The refrigerant sent to the heat source side expansion valves 26, 27 is adjusted in flow rate at the heat source side expansion valves 26, 27, and then the outdoor air supplied by the outdoor fan 34 in the heat source side heat exchangers 24, 25. By performing heat exchange, it evaporates into a low-pressure gas refrigerant and is sent to the heat exchange switching mechanisms 22 and 23. The low-pressure gas refrigerant sent to the heat exchange switching mechanisms 22, 23 evaporates in the use side heat exchanger 52 d, merges with the low-pressure gas refrigerant, and is returned to the suction side of the compressor 21.

  In this way, the operation in the simultaneous cooling and heating operation (mainly heat radiation load) is performed. Note that the heat radiation load of the entire use side heat exchangers 52a, 52b, 52c, and 52d is reduced due to a decrease in the number of use units (that is, use side heat exchangers functioning as refrigerant radiators) that perform the heating operation. In this case, by causing the first heat source side heat exchanger 24 to function as a refrigerant radiator, the heat radiation load of the first heat source side heat exchanger 24 and the evaporation load of the second heat source side heat exchanger 25 are reduced. The operation of canceling and reducing the evaporation load of the heat source side heat exchangers 24 and 25 as a whole is performed.

(3) Operation when leakage of refrigerant is detected In the cooling and heating simultaneous operation type air conditioner 1, as described above, a flammable refrigerant such as R32 is enclosed in the refrigerant circuit 10, and the leakage is detected. As the refrigerant leakage detection means, refrigerant sensors 57a, 57b, 57c, and 57d are provided. When the refrigerant leakage is detected by the refrigerant sensors 57a, 57b, 57c, 57d, the refrigerant is supplied from the usage unit in which the refrigerant leakage is detected among the usage units 3a, 3b, 3c, 3d to the heat source unit 2. It is preferable to continue the cooling operation and the heating operation of other utilization units while collecting.

  Here, when recovering the refrigerant from the utilization unit in which the refrigerant leakage is detected to the heat source unit 2, the refrigerant leakage is continued while continuing the cooling operation and the heating operation in the other utilization units where the refrigerant is not leaking. It is necessary to store the refrigerant sent from the detected utilization unit in the heat source unit 2.

  Therefore, here, when the leakage of the refrigerant is detected, the refrigerant is leaked by performing the following operation using the refrigerant adjustment container 41 and the refrigerant adjustment pipes 42 and 45, etc. While continuing the operation of other utilization units that have not been performed, the refrigerant can be recovered to the heat source unit 2 from the utilization unit in which leakage of the refrigerant has been detected.

  Next, regarding the operation when the leakage of the refrigerant is detected, the use units 3a, 3b, and 3c perform the cooling operation, and only the first heat source side heat exchanger 24 functions as a refrigerant radiator. The case where the refrigerant leaks in the usage unit 3a is described as an example with reference to FIGS. 9 and 10 (see FIG. 4). Here, FIG. 9 is a flowchart of the operation when refrigerant leakage is detected, and FIG. 10 shows the operation (refrigerant flow) when refrigerant leakage is detected during cooling operation (low evaporation load). It is a figure shown (at the time of collection | recovery to the refrigerant | coolant adjustment container 41). The operation when the refrigerant leakage is detected is also performed by the control units 20, 50a, 50b, 50c, 50d, 60a, 60b, 60c, 60d.

  First, in step ST1, when any of the refrigerant sensors 57a, 57b, 57c, and 57d as the refrigerant leakage detection means detects refrigerant leakage (here, the refrigerant sensor 57a for the use unit 3a detects refrigerant leakage). ), The process proceeds to step ST2.

  Next, in step ST2, in order to recover the refrigerant from the usage unit 3a (leakage machine) in which the refrigerant leakage is detected to the heat source unit 2, the usage unit 3a (leakage machine) in which the refrigerant leakage is detected is handled. Open and close various valves. Specifically, the high pressure gas control valve 66a and the use side expansion valve 51a corresponding to the use unit 3a (leakage machine) are closed, and the low pressure gas control valve 67a is opened. As a result, the usage unit 3a (leakage machine) is isolated from other refrigerant circuit parts, and the usage unit 3a (leakage machine) is in communication with the heat source unit 2 through the branch unit 4a and the low-pressure gas refrigerant communication pipe 9. Can do. In addition, here, in addition to opening / closing operations of various valves corresponding to the utilization unit 3a (leakage machine) in which refrigerant leakage is detected, the refrigerant adjustment inlet valve 43 is opened, and the heat source side refrigerant circuit 12 is heated. An operation of branching from the liquid side portion of the heat exchangers 24 and 45 and causing the refrigerant to flow into the refrigerant adjustment container 41 is performed. Here, the refrigerant adjustment outlet valve 46 is in a closed state.

  Thereby, the refrigerant | coolant which exists in the utilization unit 3a (leakage machine) is sent to the suction | inhalation side of the compressor 21 of the heat source unit 2 through the branch unit 4a and the low pressure gas refrigerant | coolant connecting pipe 9. FIG. Thus, the operation | movement which collect | recovers refrigerant | coolants to the heat-source unit 2 from the utilization unit 3a (leak machine) by which leakage of the refrigerant | coolant was detected is started. At this time, the refrigerant recovered to the heat source unit 2 from the utilization unit 3a (leak machine) in which the refrigerant leakage is detected is extracted from the main circulation flow of the refrigerant in the refrigerant circuit 10 (here, the heat source side heat exchangers 24 and 25). (From the liquid side) can be branched by the refrigerant adjustment tube 42 and stored in the refrigerant adjustment container 41. For this reason, even during the operation of recovering the refrigerant from the usage unit 3a (leakage machine) to the heat source unit 2, the cooling operation can be continued in the usage units 3b and 3c in which leakage of other refrigerants is not detected.

  Next, in step ST3, the recovery of the refrigerant from the usage unit 3a (leakage machine) in which the refrigerant leakage is detected to the heat source unit 2 (here, the recovery of the refrigerant from the usage unit 3a to the heat source unit 2) is completed. Determine whether or not. Specifically, from the start of refrigerant recovery in step ST2 (after the refrigerant adjustment inlet valve 43 is opened), when a predetermined time T1 has elapsed, when the refrigerant adjustment container 41 reaches the predetermined liquid level L1, or When the low pressure P in the use unit 3a (leakage machine) in which the refrigerant leakage is detected becomes equal to or lower than the predetermined pressure P1, the refrigerant collection end condition that can be regarded as the refrigerant collection is completed is satisfied. Judge that it is. That is, here, the volume of the refrigerant adjustment container 41 is large enough to store the amount of refrigerant to be collected, and from the start of refrigerant collection in step ST2 (after the refrigerant adjustment inlet valve 43 is opened). When the predetermined time T1 has elapsed or when the refrigerant adjustment container 41 has reached the predetermined liquid level L1, it is basically determined that a sufficient amount of refrigerant has been recovered. However, when the refrigerant recovered from the utilization unit in which the refrigerant leakage is detected to the heat source unit is small, a predetermined time T1 from the start of refrigerant recovery in step ST2 (after the refrigerant adjustment inlet valve 43 is opened). Before the refrigerant adjustment container 41 reaches the predetermined liquid level L1, there may be no refrigerant to be recovered by the heat source unit 2 from the use unit 3a (leaker) in which refrigerant leakage is detected. . Therefore, here, the determination condition based on the low pressure P in the use unit 3a (leakage machine) in which the refrigerant leakage is detected is added together with the determination condition based on the time and the liquid level. Here, whether or not the refrigerant adjustment container 41 has reached the predetermined liquid level L1 is determined based on the temperature on the discharge side of the compressor 21 when the liquid refrigerant is returned from the refrigerant adjustment container 41 to the compressor 21 through the liquid level detection tube 48. (Temperature Td detected by the discharge temperature sensor 40) is reduced. Specifically, the liquid level detection valve 49 is opened, and the temperature (here, the discharge side of the compressor 21). When the temperature Td) detected by the discharge temperature sensor 40 becomes equal to or lower than the predetermined temperature Td1, it is determined that the liquid level has reached the predetermined liquid level L1. Further, whether or not the low pressure P in the use unit 3a (leakage machine) in which refrigerant leakage is detected has become equal to or lower than the predetermined pressure P1 is determined by the temperature of the refrigerant in the use side heat exchanger 52a of the use unit 3a (leakage machine). Specifically, the pressure of the refrigerant in the use side heat exchanger 52a of the use unit 3a (leakage machine) (here, the temperature detected by the liquid side temperature sensor 58a) is used. When the low pressure P), which is a pressure value converted into the saturation pressure, becomes equal to or lower than the predetermined pressure P1, the refrigerant to be recovered by the heat source unit 2 from the use unit 3a (leak machine) in which leakage of the refrigerant is detected. It is determined that it has disappeared.

  Note that the refrigerant recovery end condition is not limited to a combination of all the above three conditions, but any combination of two conditions such as a combination of time and low pressure or a combination of liquid level and low pressure. Or only one of the conditions may be used. And as a refrigerant | coolant collection | recovery completion | finish condition, when employ | adopting the determination conditions by the low pressure P in the utilization unit 3a (leakage machine) by which the refrigerant | coolant leakage was detected, from the utilization unit 3a (leakage machine) by which the refrigerant | coolant leakage was detected. After confirming that there is no refrigerant to be recovered in the heat source unit 2, the refrigerant recovery can be finished promptly.

  Next, in step ST4, in order to end the recovery of the refrigerant from the use unit 3a (leak machine) in which the refrigerant leak is detected to the heat source unit 2, the use unit 3a (leak machine) in which the refrigerant leak is detected. Open and close various valves corresponding to. Specifically, the high pressure gas control valve 66a and the low pressure gas control valve 67a corresponding to the use unit 3a (leakage machine) are closed. Then, the refrigerant adjustment inlet valve 43 opened to recover the refrigerant is closed, and the refrigerant is supplied from the liquid side portions of the heat source side heat exchangers 24 and 45 of the heat source side refrigerant circuit 12 to the refrigerant adjustment container 41. Perform an operation to prevent inflow. In step ST2, when the liquid level detection pipe 48 is detecting the liquid level of the refrigerant adjustment container 41, an operation of closing the liquid level detection valve 49 is also performed.

  Thereby, a refrigerant | coolant can be collect | recovered to the heat-source unit 2 from the utilization unit 3a (leak machine) by which the leakage of the refrigerant | coolant was detected. And after collection | recovery of a refrigerant | coolant is complete | finished, the utilization unit 3a (leakage machine) and the liquid level adjustment container 41 can be made into the state isolated from the other refrigerant circuit parts. Further, even after the refrigerant is recovered, the cooling operation in the use units 3b and 3c in which leakage of other refrigerants is not detected can be continued as in the case of the refrigerant recovery.

  Here, in the case where the usage units 3a, 3b, and 3c are performing the cooling operation and only the first heat source side heat exchanger 24 functions as a refrigerant radiator, Although the case where leakage has occurred has been described as an example, the above-described refrigerant recovery operation using the refrigerant adjustment container 41 and the refrigerant adjustment pipes 42 and 45 can be performed even in the case of heating operation or simultaneous cooling and heating operation. It is.

(4) Modified Example When the refrigerant sensors 57a, 57b, 57c, and 57d as refrigerant leakage detecting means detect refrigerant leakage as in the above embodiment, the refrigerant adjustment inlet valve 43 is opened to adjust refrigerant. In the method of recovering the refrigerant in the container 41, if there is a large amount of refrigerant recovered from the use unit in which leakage of the refrigerant is detected to the heat source unit 2, or if the volume of the refrigerant adjustment container 41 is small, the refrigerant adjustment container 41 has a refrigerant. May not be able to accumulate.

  Therefore, here, when the refrigerant sensors 57a, 57b, 57c, and 57d as the refrigerant leakage detection means detect the leakage of the refrigerant, after a predetermined time T1 has elapsed since the refrigerant adjustment inlet valve 43 was opened, or After the refrigerant adjustment container 41 reaches the predetermined liquid level L1, the heat source side heat exchangers 24 and 25 are caused to function as refrigerant radiators.

  Next, regarding the operation when the leakage of the refrigerant in the present modification is detected, the utilization units 3a, 3b, 3c are performing the cooling operation, and only the first heat source side heat exchanger 24 is the refrigerant radiator. The case where the refrigerant leaks in the use unit 3a as an example will be described with reference to FIGS. Here, FIG. 11 and FIG. 12 are flowcharts of operations when refrigerant leakage is detected in the present modification, and FIG. 13 is a flowchart when refrigerant leakage is detected during cooling operation (low evaporation load). It is a figure (at the time of recovery to the 2nd heat source side heat exchanger 25) which shows operation (flow of a refrigerant). The operation when the refrigerant leakage is detected according to this modification is also performed by the control units 20, 50a, 50b, 50c, 50d, 60a, 60b, 60c, and 60d. Further, the processes in steps ST1, ST2, and ST4 are the same as those in steps ST1, ST2, and ST4 in the above-described embodiment (see FIG. 9). Therefore, the description is omitted here, and the processes in steps ST13 to ST17 are described. To do.

  In steps ST13 and ST14, it is determined whether or not the refrigerant recovery end condition is satisfied in the state in which the refrigerant is being collected in the refrigerant adjustment container 41 (see FIG. 10), as in step ST3 of the above embodiment.

  However, here, before satisfying the determination condition based on the time and the liquid level in step ST14 (that is, since the refrigerant adjustment inlet valve 43 in step ST2 is opened), the predetermined time T1 has not elapsed, and the refrigerant adjustment The refrigerant leaks only when the container 41 has not reached the predetermined liquid level L1 and the determination condition due to the low pressure in step ST13 is satisfied (when the low pressure P in the leaking machine becomes equal to or lower than the predetermined pressure P1). Assuming that the refrigerant to be recovered from the detected use unit 3a (leakage machine) to the heat source unit 2 runs out, the refrigerant adjustment inlet valve 43 is closed and the refrigerant adjustment container is in the same manner as in step ST4 of the above embodiment. The refrigerant recovery to 41 is finished.

  On the other hand, when the determination condition by the low pressure in step ST13 is satisfied (that is, when the low pressure P in the leaker is not equal to or lower than the predetermined pressure P1) and the determination condition by the time and the liquid level in step ST14 is satisfied ( That is, when the predetermined time T1 has elapsed since the refrigerant adjustment inlet valve 43 in step ST2 is opened or when the refrigerant adjustment container 41 has reached the predetermined liquid level L1), the refrigerant adjustment container 41 has a refrigerant. However, it is assumed that there is still a refrigerant to be collected, but the process proceeds to step ST15.

  In step ST15, the refrigerant adjustment inlet valve 43 is closed to complete the recovery of the refrigerant into the refrigerant adjustment container 41 and to increase the number of heat source side heat exchangers 24 and 25 that function as refrigerant radiators. Do. Specifically, when there is a stopped heat source side heat exchanger among a plurality (here, two) of the heat source side heat exchangers 24 and 25, the stopped heat source side heat exchanger is replaced with the refrigerant. In order to function as a radiator, the heat exchange switching mechanism corresponding to the stopped heat source side heat exchanger is switched to the heat radiation operation state, and the heat source side expansion valve corresponding to the stopped heat source side heat exchanger is opened. To. Also, there is no stopped heat source side heat exchanger among the plurality (here, two) of heat source side heat exchangers 24, 25, but there is a heat source side heat exchanger that functions as a refrigerant evaporator. In order to make the heat source side heat exchanger functioning as a refrigerant evaporator function as a refrigerant radiator, the heat exchange switching mechanism corresponding to the heat source side heat exchanger functioning as a refrigerant evaporator is put into a heat radiation operation state. The heat source side expansion valve corresponding to the heat source side heat exchanger that functions as a refrigerant evaporator is switched to an open state. Here, the use units 3a, 3b, and 3c are performing a cooling operation, and only the first heat source side heat exchanger 24 functions as a refrigerant radiator. In order to function the second heat source side heat exchanger 25 as a refrigerant radiator, the second heat exchange switching mechanism 23 corresponding to the stopped second heat source side heat exchanger 25 is switched to the heat radiation operation state, and The second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 being stopped is opened.

  Thus, here, after the predetermined time T1 has elapsed since the refrigerant adjustment inlet valve 43 was opened, or after the refrigerant adjustment container 41 has reached the predetermined liquid level L1, the heat source side heat exchanger (here, The second heat source side heat exchanger 25) functions as a refrigerant radiator. As a result, when the refrigerant is recovered from the use unit 3a (leak machine) in which the refrigerant leakage is detected to the heat source unit 2, the refrigerant that cannot be stored in the refrigerant adjustment container 41 is converted into the heat source side heat exchangers 24, 25 (here) Then, it can be stored in the second heat source side heat exchanger 25). In addition, here, as described above, the second heat source side heat exchanger 25 having a large volume out of the two heat source side heat exchangers 24 and 25 is caused to function as a refrigerant radiator. It is possible to reliably store the refrigerant that cannot be stored in 41.

  Then, in step ST16, it is determined whether or not the same low pressure determination condition as in step ST13 is satisfied, and there is no refrigerant to be recovered in the heat source unit 2 from the use unit 3a (leaker) in which refrigerant leakage is detected. After that, in step ST17, in order to end the recovery of the refrigerant from the use unit 3a (leak machine) in which the refrigerant leak is detected to the heat source unit 2, the use unit 3a (leak machine) in which the refrigerant leak is detected. Open and close various valves corresponding to. Specifically, the high pressure gas control valve 66a and the low pressure gas control valve 67a corresponding to the use unit 3a (leakage machine) are closed. And operation which returns the heat source side heat exchanger which functions as a heat radiator of the refrigerant increased in order to collect | recover a refrigerant | coolant to the original state is performed. Specifically, in the case where the heat source side heat exchanger that has been stopped among a plurality (here, two) of the heat source side heat exchangers 24 and 25 is functioning as a refrigerant radiator, the stopped state In order to return to, the corresponding heat source side expansion valve is closed. In addition, when a heat source side heat exchanger functioning as a refrigerant evaporator among a plurality (here, two) of heat source side heat exchangers 24 and 25 is functioning as a refrigerant radiator, In order to return to the state of functioning as an evaporator, the corresponding heat exchange switching mechanism is switched to the evaporation operation state. Here, the case where the use units 3a, 3b, and 3c are performing the cooling operation and only the first heat source side heat exchanger 24 functions as a refrigerant radiator is taken as an example. In order to return the second heat source side heat exchanger 25 that has been functioning as a refrigerant radiator for recovery to a stopped state, the second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 is provided. Close.

  Here, in the case where the usage units 3a, 3b, and 3c are performing the cooling operation and only the first heat source side heat exchanger 24 functions as a refrigerant radiator, Although the case where leakage has occurred has been described as an example, the above-described refrigerant recovery operation can be performed even in the case of heating operation or simultaneous cooling / heating operation.

  Specifically, for example, the usage units 3a, 3b, 3c, and 3d perform the heating operation, and both the heat source side heat exchangers 24 and 25 function as a refrigerant radiator (heat dissipation). In the case of a large load) (see FIG. 5), since the high-pressure gas control valve 66a and the use-side expansion valve 51a are open and the low-pressure gas control valve 67a is closed, leakage of the refrigerant is detected. In order to recover the refrigerant from the used unit 3a (leakage machine) to the heat source unit 2, in step ST2, the high pressure gas control valve 66a and the use side expansion valve 51a are closed, and the low pressure gas control valve 67a and the refrigerant adjustment inlet valve The operation of opening 43 is performed. Thereafter, if it is determined in steps ST13 and ST14 that the refrigerant cannot be fully stored in the refrigerant adjustment container 41, one of the heat source side heat exchangers 24 and 25 functioning as an evaporator of the refrigerant (for example, the first In order to cause the two heat source side heat exchanger 25) to function as a refrigerant radiator, in step ST15, the second heat exchange switching mechanism 23 corresponding to the second heat source side heat exchanger 25 is switched to the heat radiation operation state, and The second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 is opened (see FIG. 14).

  Further, for example, in the case of heating operation (small heat radiation load) in which the usage units 3a, 3b, and 3c are performing the heating operation and only the first heat source side heat exchanger 24 functions as a refrigerant radiator ( In FIG. 6), since the high-pressure gas control valve 66a and the use-side expansion valve 51a are in the open state and the low-pressure gas control valve 67a is in the closed state, the use unit 3a (the refrigerant leakage is detected) In order to recover the refrigerant from the leaker) to the heat source unit 2, in step ST2, the high-pressure gas adjustment valve 66a and the use-side expansion valve 51a are closed, and the low-pressure gas adjustment valve 67a and the refrigerant adjustment inlet valve 43 are opened. . Thereafter, when it is determined in steps ST13 and ST14 that the refrigerant cannot be fully stored in the refrigerant adjustment container 41, in order to function the stopped second heat source side heat exchanger 25 as a refrigerant radiator, step In ST15, the second heat exchange switching mechanism 23 corresponding to the second heat source side heat exchanger 25 is switched to the heat radiation operation state, and the second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 is opened. (See FIG. 15).

  Further, for example, the use units 3a, 3b, and 3c perform the cooling operation, the use unit 3d performs the heating operation, and only the first heat source side heat exchanger 24 functions as a refrigerant radiator. In the case of simultaneous operation (mainly evaporation load) (see FIG. 7), since the low-pressure gas control valve 67a and the use-side expansion valve 51a are open and the high-pressure gas control valve 66a is closed, the refrigerant In order to recover the refrigerant from the use unit 3a (leak machine) in which the leakage of the heat is detected to the heat source unit 2, in step ST2, an operation of closing the use side expansion valve 51a and opening the refrigerant adjustment inlet valve 43 is performed. Thereafter, when it is determined in steps ST13 and ST14 that the refrigerant cannot be fully stored in the refrigerant adjustment container 41, in order to function the stopped second heat source side heat exchanger 25 as a refrigerant radiator, step In ST15, the second heat exchange switching mechanism 23 corresponding to the second heat source side heat exchanger 25 is switched to the heat radiation operation state, and the second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 is opened. The state is set (see FIG. 16).

  Further, for example, the use units 3a, 3b, and 3c perform heating operation, the use unit 3d performs cooling operation, and both the heat source side heat exchangers 24 and 25 function as a refrigerant evaporator. In the case of operation (mainly a heat radiating load) (see FIG. 8), the high-pressure gas control valve 66a and the use-side expansion valve 51a are open and the low-pressure gas control valve 67a is closed. In order to recover the refrigerant from the use unit 3a (leak machine) in which leakage has been detected to the heat source unit 2, in step ST2, the high-pressure gas control valve 66a and the use-side expansion valve 51a are closed, and the low-pressure gas control valve 67a and the refrigerant An operation of opening the adjustment inlet valve 43 is performed. Thereafter, if it is determined in steps ST13 and ST14 that the refrigerant cannot be fully stored in the refrigerant adjustment container 41, one of the heat source side heat exchangers 24 and 25 functioning as an evaporator of the refrigerant (for example, the first In order to cause the two heat source side heat exchanger 25) to function as a refrigerant radiator, in step ST15, the second heat exchange switching mechanism 23 corresponding to the second heat source side heat exchanger 25 is switched to the heat radiation operation state, and The second heat source side expansion valve 27 corresponding to the second heat source side heat exchanger 25 is opened (see FIG. 17).

(5) Other Modifications In the embodiment and the modification described above, only one heat source unit 2 is provided. However, the heat source unit 2 is not limited to this and may be two or more. Moreover, in said embodiment and modification, although the several heat source side heat exchanger is comprised from the two heat source side heat exchangers 24 and 25, it is not limited to this, For example, three or more You may be comprised from the heat source side heat exchanger.

  In the above embodiment and the modification, the branch units 4a, 4b, 4c, and 4d corresponding to the plurality of usage units 3a, 3b, 3c, and 3d are connected, but the present invention is not limited to this. The branch unit may be configured to be grouped for each of a plurality of usage units.

  In the above-described embodiments and modifications, the refrigerant sensors 57a, 57b, 57c, and 57d as the refrigerant leakage detection means are provided in the usage units 3a, 3b, 3c, and 3d. However, the present invention is not limited to this. The sensors 57a, 57b, 57c, and 57d may be provided in the indoor space where the utilization units 3a, 3b, 3c, and 3d are installed. In the above-described embodiment and modification, the refrigerant sensors 57a, 57b, 57c, and 57d are used as the refrigerant leakage detection means. However, the present invention is not limited to this, and the state of the refrigeration cycle operation (high pressure time) The presence or absence of refrigerant leakage may be detected by a change).

  In the above embodiment and modification, the liquid level detection tube 48 is used to detect the liquid level of the refrigerant adjustment container 41. However, the present invention is not limited to this, and a liquid level sensor or the like is used. May be.

  In the above-described embodiment and modification, the temperature detected by the liquid-side temperature sensors 58a, 58b, 58c, and 58d is used for the low pressure in the utilization unit in which the refrigerant leakage is detected. However, the present invention is not limited to this. Instead, a pressure sensor may be provided, or a temperature detected by another temperature sensor may be used.

  The present invention is widely applicable to a cooling and heating simultaneous operation type air conditioner configured by connecting a plurality of utilization units, branching units, and heat source units via three refrigerant communication pipes.

DESCRIPTION OF SYMBOLS 1 Heating / cooling simultaneous operation type air conditioner 2 Heat source unit 3a, 3b, 3c, 3d Use unit 4a, 4b, 4c, 4d Branch unit 7 Liquid refrigerant communication pipe 8 High and low pressure gas refrigerant communication pipe 9 Low pressure gas refrigerant communication pipe 21 Compressor 24 1st heat source side heat exchanger 25 2nd heat source side heat exchanger 41 Refrigerant adjustment container 42, 45 Refrigerant adjustment pipe 43 Refrigerant adjustment inlet valve 51a, 51b, 51c, 51d Use side expansion valve 52a, 52b, 52c, 52d Use Side heat exchanger 57a, 57b, 57c, 57d Refrigerant sensor (refrigerant leakage detection means)
66a, 66b, 66c, 66d High pressure gas regulating valve 67a, 67b, 67c, 67d Low pressure gas regulating valve

JP 2009-299910 A

Claims (4)

A plurality of utilization units (3a, 3b, 3c, 3d) having utilization side expansion valves (51a, 51b, 51c, 51d) and utilization side heat exchangers (52a, 52b, 52c, 52d);
A heat source unit (2) having a compressor (21) and a plurality of heat source side heat exchangers (24, 25);
A high and low pressure gas refrigerant communication pipe (8) drawn from the heat source unit;
A low-pressure gas refrigerant communication pipe (9) drawn from the heat source unit;
A liquid refrigerant communication pipe (7) drawn from the heat source unit;
The use units are connected to the high-low pressure gas refrigerant communication pipe, the low-pressure gas refrigerant communication pipe, and the liquid refrigerant communication pipe, and high-pressure gas control valves (66a, 66b, 66c, 66d) corresponding to the use units. ) And a branch unit (4a, 4b, 4c, 4d) having low pressure gas control valves (67a, 67b, 67c, 67d);
With
Refrigerant leakage detection means (57a, 57b, 57c, 57d) for detecting refrigerant leakage is provided,
Refrigerant adjustment pipes (42, 45) are connected to the heat source unit so as to branch the refrigerant from the liquid side of the heat source side heat exchanger,
The refrigerant adjustment pipe is provided with a refrigerant adjustment container (41) capable of storing refrigerant, and a refrigerant adjustment inlet valve (43) is provided on the inlet side of the refrigerant adjustment container,
When the refrigerant leakage detection means detects refrigerant leakage, the refrigerant adjustment inlet valve is opened, and the refrigerant is collected from the use unit in which refrigerant leakage is detected into the refrigerant adjustment container of the heat source unit. And
After a predetermined time has elapsed since the refrigerant adjustment inlet valve was opened,
The refrigerant adjustment inlet valve is closed to end the recovery of the refrigerant into the refrigerant adjustment container, and the number of the heat source side heat exchangers functioning as a refrigerant radiator is increased, and refrigerant leakage is detected. Recovering the refrigerant from the utilization unit to the heat source side heat exchanger of the heat source unit;
Cooling and heating simultaneous operation type air conditioner (1). A plurality of utilization units (3a, 3b, 3c, 3d) having utilization side expansion valves (51a, 51b, 51c, 51d) and utilization side heat exchangers (52a, 52b, 52c, 52d);
A heat source unit (2) having a compressor (21) and a plurality of heat source side heat exchangers (24, 25);
A high and low pressure gas refrigerant communication pipe (8) drawn from the heat source unit;
A low-pressure gas refrigerant communication pipe (9) drawn from the heat source unit;
A liquid refrigerant communication pipe (7) drawn from the heat source unit;
The use units are connected to the high-low pressure gas refrigerant communication pipe, the low-pressure gas refrigerant communication pipe, and the liquid refrigerant communication pipe, and high-pressure gas control valves (66a, 66b, 66c, 66d) corresponding to the use units. ) And a branch unit (4a, 4b, 4c, 4d) having low pressure gas control valves (67a, 67b, 67c, 67d);
With
Refrigerant leakage detection means (57a, 57b, 57c, 57d) for detecting refrigerant leakage is provided,
Refrigerant adjustment pipes (42, 45) are connected to the heat source unit so as to branch the refrigerant from the liquid side of the heat source side heat exchanger,
The refrigerant adjustment pipe is provided with a refrigerant adjustment container (41) capable of storing refrigerant, and a refrigerant adjustment inlet valve (43) is provided on the inlet side of the refrigerant adjustment container,
When the refrigerant leakage detection means detects refrigerant leakage, the refrigerant adjustment inlet valve is opened, and the refrigerant is collected from the use unit in which refrigerant leakage is detected into the refrigerant adjustment container of the heat source unit. And
After the refrigerant adjustment container reaches a predetermined liquid level,
The refrigerant adjustment inlet valve is closed to end the recovery of the refrigerant into the refrigerant adjustment container, and the number of the heat source side heat exchangers functioning as a refrigerant radiator is increased, and refrigerant leakage is detected. Recovering the refrigerant from the utilization unit to the heat source side heat exchanger of the heat source unit;
Cooling and heating simultaneous operation type air conditioner (1). The heat source side heat exchanger includes a first heat source side heat exchanger (24) and a second heat source side heat exchanger (25) having a larger volume than the first heat source side heat exchanger. ,
After a predetermined time has elapsed since the refrigerant adjustment inlet valve (43) was opened, or after the refrigerant adjustment container (41) has reached a predetermined liquid level, the second heat source side heat exchanger is connected to the refrigerant. To function as a radiator,
The cooling and heating simultaneous operation type air conditioner (1) according to claim 1 or 2 . Refrigerant from the utilization unit in which leakage of refrigerant is detected to the heat source unit (2) after the low pressure in the utilization units (3a, 3b, 3c, 3d) in which leakage of refrigerant has been detected becomes a predetermined pressure or less. End the collection of
The cooling and heating simultaneous operation type air conditioner (1) according to any one of claims 1 to 3 .

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