JP2016011782A - Heating/cooling simultaneous operation type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable refrigerant recovery from a utilization unit where refrigerant leakage is detected to a heat source unit while continuing the operation of other utilization units where refrigerant does not leak in a heating/cooling simultaneous operation type air conditioner configured by connecting a plurality of utilization units, branch units and heat source units through three refrigerant communication pipes.SOLUTION: A heating/cooling simultaneous operation type air conditioner(1) includes refrigerant leakage detection means (57a,57b,57c,57d) that detect refrigerant leakage. During an operation where there exist a heat source unit in which a heat source side heat exchanger operates as a heat radiator of a refrigerant and a heat source unit in which a heat source side heat exchanger operates as an evaporator of the refrigerant, when refrigerant leakage is detected, the refrigerant is recovered from a utilization unit where refrigerant leakage is detected to the heat source unit in which the heat source side heat exchanger operates as the heat radiator of the refrigerant by increasing a high pressure in the heat source unit in which the heat source side heat exchanger operates as the heat radiator of the refrigerant.

Description

  The present invention relates to a cooling and heating simultaneous operation type air conditioning apparatus, and in particular, a cooling and heating simultaneous operation type air conditioning configured by connecting a plurality of utilization units, branching units, and a plurality of heat source units via three refrigerant communication pipes. Relates to the device.

  Conventionally, as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-299910), a plurality of indoor units (use units), a cooling / heating switching unit (branch unit), and a plurality of outdoor units (heat source units) are high and low pressure gases. There is an air conditioner (cooling and heating simultaneous operation type air conditioner) configured by being connected via a connection pipe, 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 utilization units, branching units, and a plurality of heat source units via three refrigerant communication pipes. An object of the present invention is to enable the recovery of the refrigerant from the usage unit in which leakage of the refrigerant is detected to the heat source unit while continuing the operation of the other usage units that are not present.

  A cooling / heating simultaneous operation type air conditioner according to a first aspect includes a plurality of utilization units, a plurality of heat source units, a high-low pressure gas refrigerant communication tube drawn from the heat source unit, and a low-pressure gas refrigerant communication tube drawn from the heat source unit. And 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 heat source side heat exchanger. 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, there is provided a refrigerant leakage detection means for detecting refrigerant leakage, a heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator among the plurality of heat source units, and the heat source side heat exchanger is the refrigerant. In the operation where there is a heat source unit that functions as an evaporator, when the refrigerant leak detection means detects the refrigerant leak, the high pressure in the heat source unit in which the heat source side heat exchanger functions as the refrigerant radiator is leaked. The refrigerant is recovered from the utilization unit in which the refrigerant leakage is detected to the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator.

  Here, the ability of the heat source side heat exchanger to store the refrigerant of the heat source side heat exchanger of the heat source unit by making the high pressure in the heat source unit that functions as a refrigerant radiator higher than before detecting leakage of the refrigerant. Can be increased. And the refrigerant | coolant collect | recovered by the heat-source unit from the utilization unit by which leakage of the refrigerant | coolant was detected can be stored in the heat-source side heat exchanger of the said heat-source unit. 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.

  The cooling / heating simultaneous operation type air conditioning apparatus according to the second aspect is the same as the cooling / heating simultaneous operation type air conditioning apparatus according to the first aspect, wherein the heat source unit heat exchanger functions as a refrigerant radiator. By making the rotational speed relatively larger than that before the refrigerant leakage is detected with respect to the rotational speed of the compressor included in the heat source unit in which the heat source side heat exchanger functions as the refrigerant evaporator, The exchanger increases the high pressure in the heat source unit that functions as a refrigerant radiator.

  Here, the heat source side heat exchanger increases the number of rotations of the compressor included in the heat source unit that functions as the refrigerant radiator, so that the heat source side heat exchanger functions more than the heat source unit that functions as the refrigerant evaporator. The heat exchanger can easily flow the refrigerant to the heat source unit that functions as a refrigerant radiator. Thereby, when recovering the refrigerant from the utilization unit in which the leakage of the refrigerant is detected to the heat source unit, a large amount of the refrigerant can be distributed to the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator.

  The cooling / heating simultaneous operation type air conditioning apparatus according to the third aspect is the same as the cooling / heating simultaneous operation type air conditioning apparatus according to the first aspect, wherein each heat source unit is connected to the liquid side of the heat source side heat exchanger. The heat source side heat exchanger has a valve, and the opening of the heat source side expansion valve of the heat source unit that the heat source side heat exchanger functions as a refrigerant radiator is made smaller than before the refrigerant leakage is detected. The exchanger increases the high pressure in the heat source unit that functions as a refrigerant radiator.

  Here, by reducing the opening of the heat source side expansion valve of the heat source unit that the heat source side heat exchanger functions as a refrigerant radiator than before detecting the leakage of the refrigerant, the corresponding heat source side heat exchanger The refrigerant can be easily stored. Thereby, when recovering the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit, the heat source side heat exchanger can store as much of the refrigerant distributed to the heat source unit that functions as a refrigerant radiator. .

  The cooling / heating simultaneous operation type air conditioning apparatus according to the fourth aspect is the same as the cooling / heating simultaneous operation type air conditioning apparatus according to the third aspect, wherein the utilization side expansion valve of the utilization unit other than the utilization unit in which leakage of the refrigerant is detected is opened. The degree is made larger than before the refrigerant leakage is detected.

  When the refrigerant leakage detection means detects refrigerant leakage, if the opening of the heat source side expansion valve of the heat source unit that the heat source side heat exchanger functions as a refrigerant radiator is smaller than before detecting refrigerant leakage The balance between the thermal load of the entire plurality of utilization units and the thermal load of the plurality of heat source units may be lost.

  Therefore, here, as described above, the opening degree of the utilization side expansion valve of the utilization unit other than the utilization unit in which the leakage of the refrigerant is detected is made larger than that before the leakage of the refrigerant is detected. Thereby, it is possible to recover the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit while balancing the thermal load of the entire plurality of utilization units and the thermal load of the plurality of heat source units.

  The cooling / heating simultaneous operation type air conditioner according to the fifth aspect is the heat / cooling simultaneous operation type air conditioner according to any of the first to fourth aspects, wherein each heat source unit is connected to the liquid side of the heat source side heat exchanger. A refrigerant adjustment pipe connected to branch the refrigerant is provided, and the refrigerant adjustment pipe is provided with a refrigerant adjustment container capable of storing the refrigerant, and a refrigerant adjustment inlet valve is provided on the inlet side of the refrigerant adjustment container. Is provided. In the operation in which there is a heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator among the plurality of heat source units, and there is a heat source unit in which the heat source side heat exchanger functions as an evaporator of the refrigerant. When the refrigerant leakage detection means detects refrigerant leakage, the heat source side heat exchanger opens the refrigerant adjustment inlet valve of the heat source unit that functions as a refrigerant radiator.

  When there is a large amount of refrigerant recovered from the utilization unit in which the refrigerant leakage is detected to the heat source unit, the high pressure in the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator is more than before the refrigerant leakage is detected. There is a case where the refrigerant cannot be stored in the heat source side heat exchanger of the heat source unit only by increasing it.

  Therefore, here, as described above, the refrigerant recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit is branched from the liquid side of the heat source side heat exchanger by the refrigerant adjustment pipe, and heat source side heat exchange is performed. The heater is stored in the refrigerant adjustment container of the heat source unit that functions as a refrigerant radiator. Thus, when the refrigerant is recovered from the utilization unit in which leakage of the refrigerant is detected to the heat source unit, the heat source side heat exchanger and the refrigerant adjustment container are combined and stored even when the amount of the recovered refrigerant is large. be able to.

  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 aspect, the refrigerant is transferred from the usage unit in which leakage of the refrigerant is detected to the heat source unit while continuing the cooling operation or heating operation in the other usage unit in which the refrigerant has not leaked. Can be recovered.

  In the cooling and heating simultaneous operation type air conditioner according to the second aspect, the heat source unit heat exchanger functions as a refrigerant radiator when the refrigerant is recovered from the use unit in which refrigerant leakage is detected to the heat source unit. It is possible to distribute a large amount of refrigerant.

  In the cooling and heating simultaneous operation type air conditioning apparatus according to the third aspect, the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator when recovering the refrigerant from the utilization unit in which leakage of the refrigerant is detected to the heat source unit It is possible to accumulate as much refrigerant as possible.

  In the cooling and heating simultaneous operation type air conditioner according to the fourth aspect, the heat unit of the plurality of utilization units and the heat load of the plurality of heat source units are balanced to the heat source unit from the utilization unit in which refrigerant leakage is detected. The refrigerant can be recovered.

  In the cooling and heating simultaneous operation type air conditioner according to the fifth aspect, when recovering the refrigerant from the utilization unit in which the refrigerant leakage is detected to the heat source unit, the heat source side heat The exchanger and the refrigerant adjustment container can be stored together.

It is a schematic block diagram of the cooling-heating simultaneous operation type air conditioning apparatus concerning one Embodiment of this invention. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the cooling-heating simultaneous operation of a 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 which shows the operation | movement (flow of a refrigerant | coolant) when the leakage of a refrigerant | coolant is detected at the time of simultaneous cooling and heating operation. It is a flowchart of operation | movement when the leakage of the refrigerant | coolant in the modification 1 is detected. It is a schematic block diagram of the cooling-heating simultaneous operation type air conditioner in the modification 2. It is the schematic which shows the structure of a refrigerant | coolant adjustment container. 12 is a flowchart of an operation when a refrigerant leak is detected in Modification 2. It is a figure which shows operation | movement (flow of a refrigerant | coolant) when the leakage of a refrigerant | coolant is detected at the time of the cooling-heating simultaneous operation in the modification 2.

  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. 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 / heating simultaneous operation type air conditioner 1 includes a plurality (here, four) of use units 3a, 3b, 3c, 3d, a plurality (here, two) of heat source units 2a, 2b and branch units 4a, 4b, 4c, 4d (here, four units corresponding to each of the usage units 3a, 3b, 3c, 3d) are connected to three refrigerant communication pipes (liquid refrigerant communication pipe 7, high-low pressure gas refrigerant communication pipe 8, low-pressure gas refrigerant). It is configured by being connected via a communication pipe 9). That is, the vapor compression refrigerant circuit 10 of the cooling and heating simultaneous operation type air conditioner 1 includes heat source units 2a and 2b, utilization units 3a, 3b, 3c, and 3d, branch units 4a, 4b, 4c, and 4d, and refrigerant. The communication pipes 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 / heating simultaneous operation type air conditioner 1, a plurality of heat source units 2a, 2b are selected in accordance with the heat load of the plurality of utilization units 3a, 3b, 3c, 3d taking into consideration the heat recovery (simultaneous cooling / heating operation). It is configured to balance the heat load.

<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 units 2a and 2b via the refrigerant communication pipes 7, 8, and 9 and the branch units 4a, 4b, 4c, and 4d. It is composed.

  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 units 2a, 2b and the branch unit 4a.

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

  Next, the configuration of the heat source units 2a and 2b will be described. In addition, since the heat source unit 2a and the heat source unit 2b have the same configuration, only the configuration of the heat source unit 2a will be described here, and the configuration of the heat source unit 2b will be denoted by the reference numerals indicating the respective parts of the heat source unit 2a. Instead of the subscript “a”, the subscript “b” is added, and description of each part is omitted.

  The heat source unit 2a mainly constitutes a part of the refrigerant circuit 10 and has a heat source side refrigerant circuit 12a (in the heat source unit 2b, the heat source side refrigerant circuit 12b). The heat source side refrigerant circuit 12a mainly includes a compressor 21a, a plurality (here, two) heat exchange switching mechanisms 22a, 23a, and a plurality (here, two) heat source side heat exchangers 24a, 25a, and A plurality of (here, two) heat source side expansion valves 26a, 27a, a high / low pressure switching mechanism 30a, a liquid side closing valve 31a, a high / low pressure gas side closing valve 32a, and a low pressure gas side closing valve 33a. Have.

  Here, the compressor 21a 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 28a.

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

  The first heat source side heat exchanger 24a 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 24a is connected to the first heat exchange switching mechanism 22a, and the liquid side thereof is connected to the first heat source side expansion valve 26a. The second heat source side heat exchanger 25a is a device for performing heat exchange between the refrigerant and the outdoor air. For example, the second heat source side heat exchanger 25a 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 25a is connected to the second heat exchange switching mechanism 23a, and the liquid side thereof is connected to the second heat source side expansion valve 27a. Here, the first heat source side heat exchanger 24a and the second heat source side heat exchanger 25a are configured as an integral heat source side heat exchanger. The heat source unit 2a has an outdoor fan 34a 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 24a and 25a are connected to the heat source unit 2a. It is possible to exchange heat with the flowing refrigerant. The outdoor fan 34a is driven by an outdoor fan motor 29a capable of controlling the rotational speed.

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

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

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

  The heat source unit 2a is provided with various sensors. Specifically, the suction pressure sensor 38a for detecting the pressure of the refrigerant on the suction side of the compressor 21a, the discharge pressure sensor 39a for detecting the pressure of the refrigerant on the discharge side of the compressor 21a, and the discharge side of the compressor 21a A discharge temperature sensor 40a for detecting the temperature of the refrigerant is provided. The heat source unit 2a includes a heat source side control unit 20a that controls operations of the respective units 22a, 23a, 26a, 27a, 28a, 29a, and 30a constituting the heat source unit 2a. And the heat source side control part 20a has the microcomputer and memory provided in order to control the heat source unit 2a, and uses side control part 50a, 50b, 50c of use unit 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 4 a, 4 b, 4 c, 4 d are interposed between the use units 3 a, 3 b, 3 c, 3 d and the heat source units 2 a, 2 b together with the refrigerant communication tubes 7, 8, 9. Part.

  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 a plurality (here, four) of use units 3a, 3b, 3c, 3d, and a plurality (here, two) of the heat source units 2a, 2b. The high-low pressure gas refrigerant communication pipe 8 drawn from the heat source units 2a and 2b, the low-pressure gas refrigerant communication pipe 9 drawn from the heat source units 2a and 2b, the liquid refrigerant communication pipe 7 drawn from the heat source units 2a and 2b, and a 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 units 2a and 2b include compressors 21a and 21b and heat source side heat exchangers 24a, 25a, 24b, and 25b. 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.

(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 FIG.

  As the refrigeration cycle operation of the cooling and heating simultaneous operation type air conditioner 1, there are various refrigeration cycle operations. As a characteristic refrigeration cycle operation, the heat source side among a plurality of (here, two) heat source units 2a and 2b. There is a simultaneous cooling and heating operation in which there is a heat source unit in which the heat exchanger functions as a refrigerant radiator and a heat source unit in which the heat source side heat exchanger functions as an evaporator of the refrigerant. That is, this simultaneous cooling / heating operation is performed by using a cooling unit (that is, an operation in which the use-side heat exchanger functions as a refrigerant evaporator) and a heating operation (ie, the use-side heat exchanger functions as a refrigerant radiator). The heat source side heat exchanger functions as a refrigerant radiator and the heat source side heat exchanger evaporates the refrigerant against the heat load of the entire utilization unit. This is a refrigeration cycle operation that balances by mixing heat source units that function as a vessel.

  In addition, operation | movement of the heating / cooling simultaneous operation type air conditioning apparatus 1 including such a refrigerating cycle operation is performed by said control part 20a, 20b, 50a, 50b, 50c, 50d, 60a, 60b, 60c, 60d.

  In the simultaneous cooling and heating operation, for example, the use units 3a and 3b are in the cooling operation, and the use units 3c and 3d are in the heating operation (that is, the use side heat exchangers 52a and 52b function as a refrigerant evaporator and are used. The side heat exchangers 52c and 52d function as a refrigerant radiator), the heat source side heat exchangers 24a and 25a exist as the refrigerant radiator, and the heat source side heat exchanger 2a exists. When performing the operation in which the heat source unit 2b in which 24b and 25b function as a refrigerant evaporator exists, the refrigerant circuit 10 of the cooling and heating simultaneous operation type air conditioner 1 is configured as shown in FIG. (See the arrows attached to the refrigerant circuit 10 in FIG. 2).

  Specifically, in the heat source unit 2a, the heat exchange side heat exchange is performed by switching the heat exchange switching mechanisms 22a and 23a to the heat radiation operation state (the state indicated by the solid lines of the heat exchange switching mechanisms 22a and 23a in FIG. 2). The devices 24a and 25a are made to function as refrigerant radiators. Moreover, the opening degree of the heat source side expansion valves 26a and 27a is adjusted. In the heat source unit 2b, the heat exchanger switching mechanisms 22b and 23b are switched to the evaporation operation state (the state shown by the broken lines of the heat exchanger switching mechanisms 22b and 23b in FIG. 2), whereby the heat source side heat exchangers 24b and 25b are switched. It is designed to function as a refrigerant evaporator. Further, the high / low pressure switching mechanism 30b is switched to the heat radiation load operation state (the state indicated by the broken line of the high / low pressure switching mechanism 30a in FIG. 2). Moreover, the opening degree of the heat source side expansion valves 26b and 27b is adjusted. In the branch units 4a, 4b, 4c, and 4d, the high pressure gas control valves 66c and 66d and the low pressure gas control valves 67a and 67b are opened, and the high pressure gas control valves 66a and 66b and the low pressure gas control valve are opened. By closing 67c and 67d, the usage-side heat exchangers 52a and 52b of the usage units 3a and 3b function as a refrigerant evaporator, and the usage-side heat exchangers 52c and 52d of the usage units 3c and 3d As a refrigerant radiator, and the use side heat exchangers 52a, 52b of the use units 3a, 3b and the suction side of the compressor 21a of the heat source unit 2a are connected via the low-pressure gas refrigerant communication tube 9 And the use side heat exchangers 52c, 52d of the use units 3c, 3d and the discharge side of the compressor 21b of the heat source unit 2b are connected to the high-low pressure gas refrigerant link. Via a tube 8 which is in 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 b of the heat source unit 2 b passes through the high-low pressure switching mechanism 30 b and the high-low pressure gas side shut-off valve 32 b to the high-low pressure gas refrigerant communication pipe 8. Sent.

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

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

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

  The high-pressure gas refrigerant compressed and discharged by the compressor 21a of the heat source unit 2a is sent to the heat source side heat exchangers 24a and 25a through the heat exchange switching mechanisms 22a and 23a. The high-pressure gas refrigerant sent to the heat source side heat exchangers 24a and 25a radiates heat by exchanging heat with outdoor air as a heat source supplied by the outdoor fan 34a in the heat source side heat exchangers 24a and 25a. The refrigerant radiated in the heat source side heat exchangers 24a and 25a is adjusted in flow rate in the heat source side expansion valves 26a and 27a, and then sent to the liquid refrigerant communication pipe 7 through the liquid side closing valve 31a.

  A part of the refrigerant sent to the liquid refrigerant communication tube 7 is sent to the heat source unit 2b, and the remainder merges with the refrigerant radiated in the use side heat exchangers 52c and 52d.

  Then, the refrigerant sent to the heat source unit 2b is sent to both the heat source side expansion valves 26b and 27b through the liquid side closing valve 31b. The refrigerant sent to the heat source side expansion valves 26b and 27b is subjected to heat exchange with the outdoor air supplied by the outdoor fan 34b in the heat source side heat exchangers 24b and 25b after the flow rate is adjusted in the heat source side expansion valves 26b and 27b. Is evaporated to become a low-pressure gas refrigerant, which is sent to the heat exchange switching mechanisms 22b and 23b. The low-pressure gas refrigerant sent to the heat exchange switching mechanisms 22b and 23b is returned to the suction side of the compressor 21b.

  Moreover, the refrigerant merged in the liquid refrigerant communication pipe 7 is branched into two and sent to the liquid connection pipes 61a and 61b of the branch units 4a and 4b.

  Then, the refrigerant sent to the liquid connection pipes 61a and 61b is sent to the use side expansion valves 51a and 51b of the use units 3a and 3b.

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

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

  Then, the low-pressure gas refrigerant sent to the low-pressure gas refrigerant communication pipe 9 is branched into two and passes through the low-pressure gas side closing valves 33a and 33b to the suction side of the compressors 21a and 21b of the heat source units 2a and 2b. Returned.

  In this way, the operation in the simultaneous cooling and heating operation is performed. Here, since it is assumed that the flow rate of the refrigerant radiated in the heat source side heat exchangers 24a and 25a of the heat source unit 2a is larger than the flow rate of the refrigerant sent to the heat source unit 2b, the heat source of the heat source unit 2a A part of the refrigerant radiated in the side heat exchangers 24a and 25a is sent to the heat source unit 2b in the liquid refrigerant communication tube 7, and the rest merges with the refrigerant radiated in the use side heat exchangers 52c and 52d. Flowing. However, when the flow rate of the refrigerant radiated in the heat source side heat exchangers 24a and 25a of the heat source unit 2a is smaller than the flow rate of the refrigerant sent to the heat source unit 2b, the heat source of the heat source unit 2a in the liquid refrigerant communication tube 7 In some cases, after the refrigerant radiated in the side heat exchangers 24a and 25a and the refrigerant radiated in the use side heat exchangers 52c and 52d merge, a part of the refrigerant flows so as to be sent to the heat source unit 2b.

(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 refrigerant leakage is detected by the refrigerant sensors 57a, 57b, 57c, and 57d, the utilization unit in which the refrigerant leakage is detected among the utilization units 3a, 3b, 3c, and 3d is transferred to the heat source units 2a and 2b. It is preferable to continue the cooling operation and heating operation of the other utilization units while collecting the refrigerant.

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

  Therefore, here, among the plurality (here, two) of heat source units 2a and 2b, there is a heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator, and the heat source side heat exchanger is made of refrigerant. In the cooling and heating simultaneous operation in which the heat source unit functioning as an evaporator is present, when the leakage of the refrigerant is detected, the following operation is performed to continue the operation of the other usage units that are not leaking the refrigerant. The refrigerant can be recovered from the use unit in which leakage of the refrigerant is detected to the heat source units 2a and 2b.

  Next, regarding the operation when refrigerant leakage is detected, the usage units 3a and 3b are in the cooling operation, the usage units 3c and 3d are in the heating operation, and the heat source side heat exchangers 24a and 25a are in the refrigerant operation. Use in the case where there is a heat source unit 2a that functions as a radiator, and the heat source side heat exchangers 24b and 25b perform operation in which there is a heat source unit 2b that functions as a refrigerant evaporator (see FIG. 2). The case where refrigerant leakage occurs in the unit 3a will be described as an example with reference to FIGS. Here, FIG. 3 is a flowchart of the operation when refrigerant leakage is detected, and FIG. 4 is a diagram illustrating the operation (refrigerant flow) when refrigerant leakage is detected during the simultaneous cooling and heating operation. . The operation when the refrigerant leakage is detected is also performed by the control units 20a, 20b, 50a, 50b, 50c, 50d, 60a, 60b, 60c, and 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, the heat source side heat exchangers 24a and 25a have a high pressure Pc1 in the heat source unit 2a that functions as a refrigerant radiator, which is higher than before the refrigerant leakage is detected, and the utilization unit in which the refrigerant leakage is detected. The heat source side heat exchangers 24a and 25a recover the refrigerant from 3a (leakage machine) to the heat source unit 2a that functions as a refrigerant radiator. For example, if the high pressure Pca in the heat source unit 2a before detecting the refrigerant leak is Pcan, the Pcar is set higher than this Pcan. Here, the high pressure Pca in the heat source unit 2a is a pressure value detected by the discharge pressure sensor 39a. Here, in order to increase the high pressure Pca in the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as a refrigerant radiator (that is, to increase from Pcan to Pcar), the heat source side heat exchangers 24a and 25a The rotation speed Na of the compressor 21a included in the heat source unit 2a that functions as a refrigerant radiator, and the rotation speed Nb of the compressor 21b included in the heat source unit 2b in which the heat source side heat exchangers 24b and 25b function as a refrigerant evaporator. On the other hand, it is made relatively larger than before detecting the leakage of the refrigerant. For example, without changing the rotational speed Nb of the compressor 21b before and after detecting the refrigerant leakage, the rotational speed Na of the compressor 21a is made larger than before the refrigerant leakage is detected, or the rotational speed Nb of the compressor 21b is detected. The ratio (= Na / Nb) of the rotational speed Na of the compressor 21a with respect to is made larger than before the refrigerant leakage is detected.

  Thereby, the refrigerant | coolant which exists in the utilization unit 3a (leakage machine) is sent to the suction side of the compressors 21a and 21b of the heat source units 2a and 2b through the branch unit 4a and the low-pressure gas refrigerant communication pipe 9. Thus, the operation | movement which collect | recovers a refrigerant | coolant to the heat-source unit 2a, 2b from the utilization unit 3a (leak machine) by which the leakage of the refrigerant | coolant was detected is started. At this time, by setting the high pressure Pca in the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as a refrigerant radiator to be higher than before detecting the leakage of the refrigerant, the heat source side heat exchanger 24a of the heat source unit 2a. , The ability to store 25a refrigerant is increasing. For this reason, the refrigerant | coolant collect | recovered by the heat source unit 2a, 2b from the utilization unit 3a (leakage machine) by which the leakage of the refrigerant | coolant was detected is accumulated in the heat source side heat exchanger 24a, 25a of the heat source unit 2a with high pressure Pca raised. be able to. In addition, here, the heat source side heat exchangers 24a and 25a increase the rotational speed Na of the compressor 21a included in the heat source unit 2a in which the heat source unit 2a functions as a refrigerant radiator, whereby the heat source side heat exchangers 24b and 25b become the refrigerant. The heat source side heat exchangers 24a and 25a can more easily flow the refrigerant to the heat source unit 2a functioning as a refrigerant radiator than the heat source unit 2b functioning as an evaporator. As a result, when the refrigerant is recovered from the utilization unit 3a (leak machine) in which refrigerant leakage is detected to the heat source units 2a and 2b, the heat source side heat exchangers 24a and 25a function as a refrigerant radiator. It is possible to distribute a large amount of refrigerant. Further, even during the operation of recovering the refrigerant from the usage unit 3a (leakage machine) to the heat source unit 2, the cooling operation and the heating operation are continued in the usage units 3b, 3c, and 3d in which other refrigerant leakage is not detected. Is possible.

  Next, in step ST3, the refrigerant is collected from the use unit 3a (leak machine) in which refrigerant leakage is detected to the heat source units 2a and 2b (here, the refrigerant is collected from the use unit 3a to the heat source units 2a and 2b). ) Is finished. Specifically, when a predetermined time has elapsed from the start of the refrigerant recovery in step ST2, it is determined that the refrigerant recovery end condition that can be regarded as the completion of the refrigerant recovery is satisfied. The refrigerant recovery end condition may use the temperature or pressure of the refrigerant in the usage-side heat exchanger 52a of the usage unit 3a (leakage machine) instead of the time from the start of the refrigerant recovery.

  Next, in step ST4, in order to end the recovery of the refrigerant from the use unit 3a (leaker) in which the refrigerant leakage is detected to the heat source units 2a and 2b, the use unit 3a (leakage in which the refrigerant leakage is detected). Open and close various valves corresponding to the machine. 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 heat source side heat exchangers 24a and 25a raised for recovering the refrigerant return the high pressure Pca of the heat source unit 2a functioning as a refrigerant radiator to the state before the refrigerant leakage is detected (original state). Perform the operation. Here, the heat source side heat exchangers 24a and 25a function as refrigerant radiators and the heat source unit 2a has a compressor 21a having a rotational speed Na as the rotational speed before the refrigerant leakage is detected (original rotational speed). Return it.

  Thereby, a refrigerant | coolant can be collect | recovered to the heat-source unit 2a 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) can be made into the state isolated from the other refrigerant circuit part. Further, even after the refrigerant is recovered, the cooling operation and the heating operation in the use units 3b, 3c, and 3d in which leakage of other refrigerants is not detected can be continued as in the case of the refrigerant recovery.

(4) Modification 1
In the above embodiment, in step ST2, in order to make the high pressure Pca in the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as the refrigerant radiators higher than before detecting the refrigerant leakage, the compressor 21a However, the present invention is not limited to this.

  For example, by making the opening MVa of the heat source side expansion valves 26a, 27a of the heat source unit 2a, in which the heat source side heat exchangers 24a, 25a function as a refrigerant radiator, smaller than before detecting refrigerant leakage, The high pressure Pca in the heat source unit 2a in which the side heat exchangers 24a and 25a function as a refrigerant radiator may be increased.

  In this case, by making the opening MVha1, MVha2 of the heat source side expansion valves 26a, 27a smaller than before detecting the leakage of the refrigerant, it is easy to store the refrigerant in the corresponding heat source side heat exchangers 24a, 25a. can do. As a result, when the refrigerant is recovered from the utilization unit 3a (leak machine) in which refrigerant leakage is detected to the heat source units 2a and 2b, the heat source side heat exchangers 24a and 25a function as a refrigerant radiator. It is possible to accumulate as much refrigerant as possible.

  However, in this way, the opening MVha1 and MVha2 of the heat source side expansion valves 26a and 27a of the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as a refrigerant radiator are more than before the refrigerant leakage is detected. If the method of making it small is adopted, there is a possibility that the balance between the thermal loads of the plurality of utilization units 3a, 3b, 3c, and 3d and the thermal loads of the plurality of heat source units 2a and 2b may be lost.

  For this reason, in step ST2, the opening MVha1 and MVha2 of the heat source side expansion valves 26a and 27a of the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as a refrigerant radiator are detected from before the refrigerant leakage is detected. The opening MVub, MVuc, MVud of the use side expansion valves 51b, 51c, 51d of the use units 3b, 3c, 3d other than the use unit 3a (leakage machine) in which the refrigerant leak is detected are It is preferable to make it larger than before leakage is detected (see step ST12 in FIG. 5). And after refrigerant | coolant collection | recovery is complete | finished, the opening degree MVub, MVuc of utilization side expansion valve 51b, 51c, 51d of utilization units 3b, 3c, 3d other than utilization unit 3a (leakage machine) by which leakage of the refrigerant | coolant was detected, The MVud is returned to the opening (original opening) before the refrigerant leakage is detected (see step ST14 in FIG. 5).

  Thereby, in this modification, the usage unit 3a in which leakage of the refrigerant is detected while balancing the thermal load of the entire plurality of usage units 3a, 3b, 3c, 3d and the thermal load of the plurality of heat source units 2a, 2b. The refrigerant can be recovered from the (leaker) to the heat source units 2a and 2b.

  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 of steps ST1 and ST3 are the same as those in the above embodiment.

(5) Modification 2
In the above embodiment and Modification 1, when there is a large amount of refrigerant recovered from the utilization unit 3a (leakage machine) in which refrigerant leakage is detected to the heat source units 2a and 2b, the heat source side heat exchangers 24a and 25a are If the high pressure Pca in the heat source unit 2a functioning as a refrigerant radiator is set higher than before detecting leakage of the refrigerant, the refrigerant may not be stored in the heat source side heat exchangers 24a and 25a of the heat source unit 2a.

  Therefore, here, when the refrigerant adjustment containers 41a and 41b are provided in the respective heat source units 2a and 2b and the refrigerant leakage is detected by the refrigerant sensors 57a, 57b, 57c, and 57d as the refrigerant leakage detection means, The heat source side heat exchanger of the heat source unit in which the side heat exchanger functions as a refrigerant radiator is used in combination with the refrigerant adjustment container, so that the refrigerant from the utilization unit in which the leakage of the refrigerant is detected is accumulated.

  Specifically, as shown in FIGS. 6 and 7, in this modification, each heat source unit 2a, 2b branches the refrigerant from the liquid side of the heat source side heat exchangers 24a, 25a, 24b, 25b. The refrigerant adjustment pipes 42a, 45a, 42b, 45b are connected, and the refrigerant adjustment pipes 42a, 45a, 42b, 45b are provided with refrigerant adjustment containers 41a, 41b capable of storing the refrigerant, Refrigerant adjustment inlet valves 43a and 43b are provided on the inlet side of the refrigerant adjustment containers 41a and 41b.

  The refrigerant adjustment tubes 42a, 45a, 42b, 45b include first refrigerant adjustment tubes 42a, 42b and second refrigerant adjustment tubes 45a, 45b. The first refrigerant adjustment pipes 42a and 42b are connected to the heat source side refrigerant circuits 12a and 12b so that one end of the first refrigerant adjustment pipes 42a and 42b branches the refrigerant from the liquid side of the heat source side heat exchangers 24a, 25a, 24b, and 25b. Are connected to the inlets of the refrigerant adjustment containers 41a and 41b. The second refrigerant adjustment pipes 45a and 45b have one end connected to the outlets of the refrigerant adjustment containers 41a and 41b and the other ends joined to the suction sides of the compressors 21a and 21b. It is connected to the. In the refrigerant adjustment pipes 42a, 45a, 42b, 45b, the inlet side of the refrigerant adjustment containers 41a, 41b, that is, the first refrigerant adjustment pipes 42a, 42b are provided with refrigerant adjustment inlet valves 43a, 43b that can be opened and closed. The refrigerant adjustment outlet valves 46a and 46b are provided on the outlet sides of the refrigerant adjustment containers 41a and 41b, that is, on the second refrigerant adjustment tubes 45a and 45b. Here, electromagnetic valves are employed as the refrigerant adjustment inlet valves 43a and 43b and the refrigerant adjustment outlet valves 46a and 46b, but electric expansion valves capable of adjusting the opening degree may be employed. The first refrigerant adjustment pipes 42a and 42b have inlet check valves 44a that allow only the flow of refrigerant from the liquid side of the heat source side heat exchangers 24a, 25a, 24b, and 25b toward the refrigerant adjustment containers 41a and 41b, 44b is provided. The second refrigerant adjustment tubes 45a and 45b are provided with outlet capillary tubes 47a and 47b for limiting the flow rate by reducing the pressure of the refrigerant flowing through the second refrigerant adjustment tubes 45a and 45b.

  The refrigerant adjustment containers 41a and 41b are containers capable of storing refrigerant, and are connected to the heat source side refrigerant circuits 12a and 12b via the refrigerant adjustment pipes 42a, 45a, 42b, and 45b. The first refrigerant adjustment pipes 42a and 42b are connected so that the refrigerant flows in from the upper parts of the refrigerant adjustment containers 41a and 41b, and the second refrigerant adjustment pipes 45a and 45b are supplied from the lower parts of the refrigerant adjustment containers 41a and 41b. Connected to drain. In addition, one end of the liquid level detection tubes 48a and 48b is connected to the refrigerant adjustment containers 41a and 41b so that the refrigerant flows out from the position of the predetermined liquid level L1 near the full liquid. The other ends of the liquid level detection pipes 48a and 48b are connected so as to merge with intermediate portions of the second refrigerant adjustment pipes 45a and 45b. The liquid level detection tubes 48a and 48b are provided with liquid level detection valves 49a and 49b that can be opened and closed. Here, electromagnetic valves are employed as the liquid level detection valves 49a and 49b, but an electric expansion valve capable of adjusting the opening degree may be employed.

  And here, operation for storing a liquid in a refrigerant | coolant adjustment container is added to step ST2, ST4 of said embodiment, and operation of step ST22, ST24 shown in FIG. 8 is performed. That is, the high pressure Pca in the heat source unit 2a in which the heat source side heat exchangers 24a and 25a function as a refrigerant radiator is made higher than before the refrigerant leakage is detected, and the heat source side heat exchangers 24a and 25a radiate the refrigerant. The refrigerant adjustment inlet valve 43a of the heat source unit 2a functioning as a container is opened.

  Then, as shown in FIG. 9, the refrigerant recovered to the heat source unit 2a from the utilization unit 3a (leak machine) in which leakage of the refrigerant is detected is transferred from the liquid side of the heat source side heat exchangers 24a and 25a to the refrigerant adjustment pipe 42a. The heat source side heat exchangers 24a and 25a can be stored in the refrigerant adjustment container 41a of the heat source unit 2a that functions as a refrigerant radiator. Thereby, when recovering the refrigerant from the utilization unit 3a (leak machine) in which the refrigerant leakage is detected to the heat source units 2a and 2b, even if the recovered refrigerant is large, the heat source side heat exchanger 24a, 25a and the refrigerant adjustment container 41a can be stored together.

  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 of steps ST1 and ST3 are the same as those in the above embodiment. Here, the operation for storing the liquid in the refrigerant adjustment container is added to steps ST2 and ST4 of the above embodiment. However, the liquid storage in the refrigerant adjustment container is performed in steps ST12 and ST14 of the first modification. You may make it add operation for doing.

(6) Other Modifications In the embodiment and the modification described above, the heat source side heat exchanger of each heat source unit 2a, 2b is composed of two heat source side heat exchangers 24a, 25a, 24b, 25b. It is not limited to this, For example, you may be comprised from one heat source side heat exchanger, and may be comprised from three or more heat source side heat exchangers.

  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).

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

DESCRIPTION OF SYMBOLS 1 Cooling and heating simultaneous operation type air conditioner 2a, 2b 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 21a , 21b Compressors 24a, 25a, 24b, 25b Heat source side heat exchangers 26a, 27a, 26b, 27b Heat source side expansion valves 41a, 41b Refrigerant adjustment containers 42a, 45a, 42b, 45b Refrigerant adjustment tubes 43a, 43b Refrigerant adjustment inlet valves 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 (5)

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 plurality of heat source units (2a, 2b) having a compressor (21a, 21b) and a heat source side heat exchanger (24a, 25a, 24b, 25b);
High and low pressure gas refrigerant communication pipes (8) drawn from the plurality of heat source units;
A low-pressure gas refrigerant communication pipe (9) drawn from the plurality of heat source units;
A liquid refrigerant communication pipe (7) drawn from the plurality of heat source units;
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,
Among the plurality of heat source units, there is the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator, and there is the heat source unit in which the heat source side heat exchanger functions as a refrigerant evaporator. In operation, when the refrigerant leakage detection means detects refrigerant leakage, the high pressure in the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator is made higher than before the refrigerant leakage is detected. Then, the heat source side heat exchanger recovers the refrigerant from the use unit in which refrigerant leakage is detected to the heat source unit that functions as a refrigerant radiator,
Cooling and heating simultaneous operation type air conditioner (1). The number of revolutions of the compressor of the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator, and the number of revolutions of the compressor in the heat source unit in which the heat source side heat exchanger functions as a refrigerant evaporator. Increasing the high pressure in the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator by making it relatively larger than that before detecting leakage of the refrigerant with respect to the rotational speed,
The cooling and heating simultaneous operation type air conditioner (1) according to claim 1. Each of the heat source units (2a, 2b) has a heat source side expansion valve (26a, 27a, 26b, 27b) connected to the liquid side of the heat source side heat exchanger (24a, 25a, 24b, 25b). And
The heat source side heat exchanger is configured such that the heat source side heat exchanger functioning as a refrigerant radiator has a smaller opening of the heat source side expansion valve than before detecting leakage of the refrigerant. Increasing the high pressure in the heat source unit that functions as a refrigerant radiator,
The cooling and heating simultaneous operation type air conditioner (1) according to claim 1. An opening degree of the use side expansion valve of the use unit other than the use unit in which leakage of the refrigerant is detected is set to be larger than that before the refrigerant leak is detected;
The cooling and heating simultaneous operation type air conditioner (1) according to claim 3. Each of the heat source units (2a, 2b) includes refrigerant adjustment tubes (42a, 45a, 42b, 45b) connected to branch the refrigerant from the liquid side of the heat source side heat exchanger (24a, 25a, 24b, 25b). )
The refrigerant adjustment pipe is provided with refrigerant adjustment containers (41a, 41b) capable of storing refrigerant, and is provided with refrigerant adjustment inlet valves (43a, 43b) on the inlet side of the refrigerant adjustment container,
Among the plurality of heat source units, there is the heat source unit in which the heat source side heat exchanger functions as a refrigerant radiator, and there is the heat source unit in which the heat source side heat exchanger functions as a refrigerant evaporator. In operation, when the refrigerant leakage detection means detects refrigerant leakage, the heat source side heat exchanger opens the refrigerant adjustment inlet valve of the heat source unit that functions as a refrigerant radiator,
The cooling and heating simultaneous operation type air conditioner (1) according to any one of claims 1 to 4.

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