JP2015075259A - Refrigeration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an error in refrigerant amount determination, in a refrigeration device having a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver and a use side heat exchanger, and capable of performing a normal operation and a refrigerant amount determination operation by switching them.SOLUTION: A refrigeration device (1) has a refrigerant circuit (10) including a compressor (21), heat source side heat exchangers (24, 25), a receiver (28) and use side heat exchangers (52a, 52b, 52c, 52d), and it is capable of performing a normal operation and a refrigerant amount determination operation by switching them. Then, here, a receiver bypass pipe (38) for bypassing the receiver (28) is connected to the refrigerant circuit (10), and in the refrigerant amount determination operation, a refrigerant is flowed in the receiver bypass pipe (38) for bypassing the receiver (28).

Description

  The present invention has a refrigerant circuit including a refrigeration apparatus, in particular, a compressor, a heat source side heat exchanger, a receiver, and a usage side heat exchanger, and according to a heat load required from the usage side heat exchanger. The present invention relates to a refrigeration apparatus that can be switched between a normal operation that is a refrigeration cycle operation and a refrigerant amount determination operation that is a refrigeration cycle operation for determining the suitability of the amount of refrigerant in a refrigerant circuit.

  Conventionally, as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-292212), a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver, and a use side heat exchanger is provided, and refrigerant amount determination is performed. There is an air conditioner (refrigeration apparatus) having a function (refrigerant amount determination function) for determining whether or not the refrigerant amount in the refrigerant circuit is appropriate by operating. This refrigeration apparatus includes a normal operation that is a refrigeration cycle operation according to a heat load required from the use side heat exchanger, and a refrigerant amount determination operation that is a refrigeration cycle operation for determining the suitability of the refrigerant amount in the refrigerant circuit. In the refrigerant quantity determination operation, the liquid level detection means such as a liquid level detection tube is used to keep the liquid level of the receiver constant and determine whether the refrigerant quantity in the refrigerant circuit is appropriate. I am doing so.

  However, when performing the refrigerant amount determination while keeping the receiver liquid level constant during the refrigerant amount determination operation, it is necessary to provide the receiver with a liquid level detection means, and a liquid level detection tube is used as the liquid level detection means. In some cases, sufficient accuracy may be difficult to obtain, and as a result, the liquid level of the receiver cannot be kept constant, and the error in determining the refrigerant amount may not be reduced. Thus, in a refrigeration apparatus having a refrigerant circuit including a receiver, it is desired to reduce an error in refrigerant amount determination when adding a refrigerant amount determination function.

  An object of the present invention is to provide a refrigeration circuit having a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver, and a usage side heat exchanger, which can be switched between a normal operation and a refrigerant amount determination operation. In the apparatus, an error in determining the refrigerant amount is to be reduced.

  The refrigeration apparatus according to the first aspect has a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver, and a use side heat exchanger, and heat required from the use side heat exchanger. It is possible to switch between a normal operation that is a refrigeration cycle operation according to the load and a refrigerant amount determination operation that is a refrigeration cycle operation for determining the suitability of the refrigerant amount in the refrigerant circuit. Here, a receiver bypass pipe that bypasses the receiver is connected to the refrigerant circuit, and in the refrigerant amount determination operation, the refrigerant is caused to flow through the receiver bypass pipe to bypass the receiver.

  Here, as described above, the refrigerant can be prevented from flowing through the receiver by the receiver bypass pipe during the refrigerant quantity determination operation. For this reason, it is possible to determine the suitability of the amount of refrigerant in the refrigerant circuit in a state where the receiver is disconnected from the refrigerant circuit (that is, a state where no refrigerant is introduced into the receiver). Thereby, the error at the time of refrigerant quantity determination can be made small here.

  The refrigeration apparatus according to the second aspect is the refrigeration apparatus according to the first aspect, wherein the refrigerant circuit is provided with a receiver backflow prevention mechanism that suppresses the refrigerant that bypasses the receiver through the receiver bypass pipe from flowing into the receiver. .

  Here, as described above, the refrigerant that bypasses the receiver by the receiver backflow prevention mechanism can be prevented from flowing into the receiver. Thereby, the state which disconnected the receiver from the refrigerant circuit at the time of a refrigerant | coolant amount determination driving | operation can be maintained here.

  The refrigeration apparatus according to the third aspect is the refrigeration apparatus according to the first or second aspect, wherein the refrigerant circuit is provided with a heat source side flow rate adjustment mechanism for adjusting a flow rate of the refrigerant flowing through the heat source side heat exchanger, A receiver bypass pipe is connected to the refrigerant circuit so as to branch from a portion between the heat source side heat exchanger and the heat source side flow rate adjusting mechanism of the refrigerant circuit.

  Here, as described above, since the receiver bypass pipe is connected so as to branch from the portion between the heat source side heat exchanger and the heat source side flow rate adjustment mechanism of the refrigerant circuit, the heat source side flow rate adjustment mechanism during normal operation. The refrigerant that has passed through the heat source side heat exchanger is guided to the receiver, and the refrigerant that has passed through the heat source side heat exchanger is guided to the receiver bypass pipe by closing the heat source side flow rate adjustment mechanism during the refrigerant amount judgment operation. The receiver can be bypassed. Thereby, here, at the time of transition from the normal operation to the refrigerant amount determination operation, the receiver can be surely switched to a state where it is disconnected from the refrigerant circuit.

  A refrigeration apparatus according to a fourth aspect is the refrigeration apparatus according to any one of the first to third aspects, wherein the receiver bypass pipe has a bypass-side flow rate adjustment mechanism that adjusts a flow rate of the refrigerant flowing through the receiver bypass pipe. ing.

  Here, as described above, since the bypass-side flow rate adjustment mechanism is provided in the receiver bypass pipe, the refrigerant that has passed through the heat source-side heat exchanger bypasses the receiver by closing the bypass-side flow rate adjustment mechanism during normal operation. In such a case, by opening the bypass side flow rate adjusting mechanism during the refrigerant amount determination operation, the refrigerant that has passed through the heat source side heat exchanger can be guided to the receiver bypass pipe to bypass the receiver. Thereby, here, when returning from the refrigerant quantity determination operation to the normal operation, it is possible to surely switch to a state in which the receiver is used.

  In the refrigeration apparatus according to the fifth aspect, in the refrigeration apparatus according to the fourth aspect, the receiver bypass pipe suppresses the reverse flow of the refrigerant from the bypass side flow rate adjustment mechanism side in the upstream portion of the bypass side flow rate adjustment mechanism. It has a bypass backflow prevention mechanism.

  Here, as described above, since the bypass backflow prevention mechanism is provided in the upstream portion of the bypass flow rate adjustment mechanism of the receiver bypass pipe, the refrigerant bypasses the receiver bypass pipe when the bypass side flow rate adjustment mechanism is opened. Backflow can be suppressed.

  A refrigeration apparatus according to a sixth aspect is the refrigeration apparatus according to the fifth aspect, wherein the receiver bypass pipe has a liquid seal prevention pipe that bypasses the bypass backflow prevention mechanism.

  Here, as described above, since the liquid seal prevention pipe that bypasses the bypass backflow prevention mechanism is provided in the receiver bypass pipe, the bypass backflow prevention mechanism and bypass of the receiver bypass pipe are closed in a state where the bypass side flow rate adjustment mechanism is closed. Liquid sealing at the portion between the side flow rate adjusting mechanism can be prevented.

  A refrigeration apparatus according to a seventh aspect is the refrigeration apparatus according to any one of the first to sixth aspects, wherein a receiver degassing pipe connecting the upper part of the receiver and the suction side of the compressor is connected to the receiver. Yes.

  Here, since the receiver degassing pipe is connected to the receiver as described above, the liquid refrigerant present in the receiver is extracted under reduced pressure by evaporating the liquid refrigerant existing in the receiver during the refrigerant amount determination operation, and the receiver Can be brought close to an empty state. Thereby, the error at the time of refrigerant quantity determination can be made still smaller here.

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

  In the refrigeration apparatus according to the first aspect, the suitability of the refrigerant amount in the refrigerant circuit can be determined with the receiver disconnected from the refrigerant circuit (that is, the refrigerant is not introduced into the receiver). The error at the time of determination can be reduced.

  In the refrigeration apparatus according to the second aspect, the state where the receiver is disconnected from the refrigerant circuit can be maintained during the refrigerant amount determination operation.

  In the refrigeration apparatus according to the third aspect, the receiver can be reliably switched to a state in which the receiver is disconnected from the refrigerant circuit at the time of transition from the normal operation to the refrigerant amount determination operation.

  In the refrigeration apparatus according to the fourth aspect, it is possible to reliably switch to the state in which the receiver is used when returning from the refrigerant quantity determination operation to the normal operation.

  In the refrigeration apparatus according to the fifth aspect, the refrigerant can be prevented from flowing back through the receiver bypass pipe in the state where the bypass-side flow rate adjustment mechanism is opened.

  In the refrigeration apparatus according to the sixth aspect, liquid sealing at the portion between the bypass backflow prevention mechanism and the bypass side flow rate adjustment mechanism of the receiver bypass pipe can be prevented while the bypass side flow rate adjustment mechanism is closed.

  In the refrigeration apparatus according to the seventh aspect, during the refrigerant amount determination operation, the liquid refrigerant present in the receiver is evaporated under reduced pressure to be extracted to the suction side of the compressor, and the receiver can be brought close to an empty state. Thus, the error in determining the refrigerant amount can be further reduced.

1 is a schematic configuration diagram of a cooling and heating simultaneous operation type air conditioning apparatus as an embodiment of a refrigeration apparatus according to the present invention. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the cooling operation of normal operation mode. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating operation of normal operation mode. 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 normal operation mode. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the heating / cooling simultaneous driving | operation (heat dissipation load main body) of normal operation mode. It is a flowchart of the refrigerant | coolant automatic charging operation of refrigerant | coolant amount determination operation mode. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the refrigerant | coolant automatic charging operation of refrigerant | coolant amount determination operation mode. It is a graph which shows the relationship between the subcooling degree of the refrigerant | coolant in the liquid side of the heat source side heat exchanger in the refrigerant | coolant amount determination driving | operation, and the refrigerant | coolant amount in a refrigerant circuit. It is a flowchart of the refrigerant | coolant leakage detection driving | operation of refrigerant | coolant amount determination operation mode. It is a figure which shows the operation | movement (flow of a refrigerant | coolant) in the refrigerant | coolant leak detection driving | operation of refrigerant | coolant amount determination operation mode.

  Hereinafter, an embodiment of a refrigeration apparatus according to the present invention will be described based on the drawings. In addition, the specific structure of the freezing apparatus concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Refrigeration Device (Cooling and Heating Simultaneous Operation Type Air Conditioner) FIG. 1 is a schematic configuration diagram of a cooling and heating simultaneous operation type air conditioning device 1 as an embodiment of the refrigeration device according to 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 and heating simultaneous operation type air conditioner 1 mainly includes one heat source unit 2, a plurality of (here, four) use units 3 a, 3 b, 3 c, 3 d, and each use unit 3 a, 3 b, 3 c, 3 d. Connecting units 4a, 4b, 4c, and 4d connected to each other, and refrigerant communication tubes 7 and 8 that connect the heat source unit 2 and the utilization units 3a, 3b, 3c, and 3d via the connection units 4a, 4b, 4c, and 4d. , 9. 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, connection units 4a, 4b, 4c, and 4d, and a refrigerant communication tube. 7, 8 and 9 are connected to each other. 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 tubes 7, 8, and 9 and the connection 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 utilization side refrigerant circuit 13a mainly has a utilization side flow rate adjustment valve 51a and a utilization side heat exchanger 52a.

  The usage-side flow rate adjustment valve 51a is an electric expansion valve that can adjust the opening degree connected to the liquid side of the usage-side heat exchanger 52a in order to adjust the flow rate of the refrigerant flowing through the usage-side heat exchanger 52a. is there.

  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 sucking indoor air into the unit and exchanging heat, and then supplying the indoor air as supply air to the indoor unit 53a. It is possible to exchange heat with the refrigerant flowing through The indoor fan 53a is driven by the indoor fan motor 54a.

  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.

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

  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, Heat source side flow rate adjustment valves 26 and 27 as heat source side flow rate adjustment mechanisms corresponding to the two heat source side heat exchangers 24 and 25, a receiver 28, a bridge circuit 29, a high / low pressure switching mechanism 30, and a liquid side closure It has a valve 31, a high / low pressure gas side closing valve 32, and a low pressure gas side closing valve 33.

  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 21a. A charging nozzle 21b used for connecting a refrigerant cylinder or the like when charging the refrigerant is connected to the suction side of the compressor 21.

  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 flow rate adjustment 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 flow rate adjustment 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. 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 34a capable of controlling the rotational speed.

  A first heat source side flow rate adjustment valve 26 as a heat source side flow rate adjustment mechanism is arranged on 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. It is an electric expansion valve that can be connected to adjust the opening. Further, the second heat source side flow rate adjustment valve 27 as the heat source side flow rate adjustment mechanism adjusts the flow rate of the refrigerant flowing through the second heat source side heat exchanger 25 and the like. This is an electric expansion valve connected to the side and capable of adjusting the opening.

  The receiver 28 is a container for temporarily storing the refrigerant flowing between the heat source side heat exchangers 24 and 25 and the use side refrigerant circuits 13a, 13b, 13c, and 13d. A receiver inlet pipe 28 a is provided in the upper part of the receiver 28, and a receiver outlet pipe 28 b is provided in the lower part of the receiver 28. The receiver inlet pipe 28a is provided with a receiver inlet on / off valve 28c capable of opening / closing control. The inlet pipe 28 a and the outlet pipe 28 b of the receiver 28 are connected between the heat source side heat exchangers 24 and 25 and the liquid side shut-off valve 31 via the bridge circuit 29.

  The receiver 28 is connected to a receiver degassing pipe 41. The receiver degassing pipe 41 is provided in the upper part of the receiver 28 separately from the receiver inlet pipe 28 a, and connects the upper part of the receiver 28 and the suction side of the compressor 21. The receiver degassing pipe 41 is provided with a receiver degassing flow rate adjusting valve 42 as a receiver degassing flow rate adjusting mechanism in order to adjust the flow rate of the refrigerant degassed from the receiver 28. Here, the receiver gas vent flow control valve 42 is an electric expansion valve capable of adjusting the opening.

  In the bridge circuit 29, when the refrigerant flows from the heat source side heat exchangers 24, 25 toward the liquid side closing valve 31 side, and when the refrigerant flows from the liquid side closing valve 31 side to the heat source side heat exchangers 24, 25 side. In any case where the refrigerant flows in the direction, the refrigerant has a function of causing the refrigerant to flow into the receiver 28 through the receiver inlet pipe 28a and out of the receiver 28 through the receiver outlet pipe 28b. The bridge circuit 29 has four check valves 29a, 29b, 29c, and 29d. The inlet check valve 29a is a check valve that only allows the refrigerant to flow from the heat source side heat exchangers 24 and 25 to the receiver inlet pipe 28a. The inlet check valve 29b is a check valve that only allows refrigerant to flow from the liquid-side closing valve 31 side to the receiver inlet pipe 28a. That is, the inlet check valves 29a and 29b have a function of circulating the refrigerant from the heat source side heat exchangers 24 and 25 side or the liquid side closing valve 31 side to the receiver inlet pipe 28a. The outlet check valve 29c is a check valve that allows only the refrigerant to flow from the receiver outlet pipe 28b to the liquid side closing valve 31 side. The outlet check valve 29d is a check valve that only allows refrigerant to flow from the receiver outlet pipe 28b to the heat source side heat exchangers 24 and 25. That is, the outlet check valves 29c and 29d have a function of circulating the refrigerant from the receiver outlet pipe 28b to the heat source side heat exchangers 24 and 25 side or the liquid side closing valve 31 side.

  The high / low pressure switching mechanism 30 compresses the high-pressure gas refrigerant discharged from the compressor 21 when the high-pressure gas refrigerant is sent to the use-side refrigerant circuits 13a, 13b, 13c, and 13d (hereinafter referred to as “radiation load main operation state”). The discharge side of the compressor 21 and 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 circuit 13a, When not sent to 13b, 13c, 13d (hereinafter referred to as "evaporative load main operation state"), the high / low pressure gas side shut-off valve 32 and the suction side of the compressor 21 are connected (high in FIG. 1). (Refer to the solid line of the low-pressure switching 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. The liquid side closing valve 31 is connected to the receiver inlet pipe 28a or the receiver outlet pipe 28b via the bridge circuit 29. The high / low pressure gas side closing valve 32 is connected to the high / low pressure switching mechanism 30. The low pressure gas side closing valve 33 is connected to the suction side of the compressor 21.

  A receiver bypass pipe 38 that bypasses the receiver 28 is connected to the heat source side refrigerant circuit 12 that is a part of the refrigerant circuit 10. The receiver bypass pipe 38 is a state in which the receiver 28 is disconnected from the refrigerant circuit 10 so as not to flow the refrigerant to the receiver 28 by flowing the refrigerant and bypassing the receiver 28 in the refrigerant amount determination operation described later (that is, This is a refrigerant pipe for setting the refrigerant in a state where no refrigerant is introduced into the receiver 28. Here, the receiver bypass pipe 38 is branched from a portion between the heat source side heat exchangers 24 and 25 of the heat source side refrigerant circuit 12 and the heat source side flow rate adjustment valves 26 and 27 as a heat source side flow rate adjustment mechanism. The receiver bypass pipe 38 merges with the receiver outlet pipe 28 b on the outlet side of the receiver 28. The receiver outlet pipe 28b is provided with a receiver backflow prevention check valve 28d as a receiver backflow prevention mechanism for suppressing the refrigerant bypassing the receiver 28 through the receiver bypass pipe 38 from flowing into the receiver 28. Here, the check valve 28d for preventing the backflow of the receiver is a check valve provided at a portion between the outlet of the receiver 28 in the receiver outlet pipe 28b and the joining portion of the receiver bypass pipe 38.

  The receiver bypass pipe 38 mainly includes a first bypass branch pipe 38a branched from the liquid side of the first heat source side heat exchanger 24 and a second bypass branch branched from the liquid side of the second heat source side heat exchanger 25. It has a pipe 38b and a bypass merging pipe 38c that joins the bypass branch pipes 38a and 38b. The receiver bypass pipe 38 is provided with a bypass-side flow rate adjustment valve 39 as a bypass-side flow rate adjustment mechanism in order to adjust the flow rate of the refrigerant flowing through the receiver bypass pipe 38. Here, the bypass-side flow rate adjustment valve 39 is an electric expansion valve provided in the bypass merging pipe 38c and capable of adjusting the opening degree. In addition, the receiver bypass pipe 38 has a check valve 40a for bypass backflow prevention as a bypass backflow prevention mechanism that suppresses the backflow of the refrigerant from the bypass side flow rate adjustment valve 39 side at a portion upstream of the bypass side flow rate adjustment valve 39. , 40b. Here, the check valves 40a and 40b for bypass backflow prevention are check valves provided in the bypass branch pipes 38a and 38b. Furthermore, the receiver bypass pipe 38 is provided with a liquid seal prevention pipe 38d that bypasses the bypass backflow prevention check valves 40a and 40b. Here, the liquid seal prevention pipe 38d is branched from the liquid side of the first heat source side heat exchanger 24, and the outlet side of the bypass backflow check check valves 40a and 40b of the receiver bypass pipe 38 and the bypass side flow control valve. 39 is a refrigerant tube that merges with the portion 39 and has a capillary tube.

  The heat source unit 2 is provided with various sensors. Specifically, a suction pressure sensor 71 that detects the pressure of the refrigerant on the suction side of the compressor 21, a suction temperature sensor 72 that detects the temperature of the refrigerant on the suction side of the compressor 21, and a discharge side of the compressor 21 A discharge pressure sensor 73 for detecting the pressure of the refrigerant and a liquid side temperature sensor 74 for detecting the temperature of the refrigerant on the liquid side of the heat source side heat exchangers 24 and 25 are provided. Further, the heat source unit 2 includes a heat source side control unit 20 that controls operations of the respective units 21 a, 22, 23, 26, 27, 28 c, 30, 34 a, 39, and 41 constituting 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.

<Connection unit>
The connection 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 connection units 4 a, 4 b, 4 c, 4 d are interposed between the use units 3, 4, 5 and the heat source unit 2 together with the refrigerant communication tubes 9, 10, 11, and constitute a part of the refrigerant circuit 10. ing.

  Next, the configuration of the connection units 4a, 4b, 4c, and 4d will be described. Since the connection unit 4a and the connection units 4b, 4c, and 4d have the same configuration, only the configuration of the connection unit 4a will be described here, and the configuration of the connection 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 connection unit 4a mainly constitutes a part of the refrigerant circuit 10, and includes a connection side refrigerant circuit 14a (in the connection units 4b, 4c, and 4d, connection side refrigerant circuits 14b, 14c, and 14d, respectively). Yes. The connection side refrigerant circuit 14a mainly includes a liquid connection pipe 61a and a gas connection pipe 62a.

  The liquid connection pipe 61a connects the liquid refrigerant communication pipe 7 and the use side flow rate adjustment valve 51a of the use side refrigerant circuit 13a.

  The gas connection pipe 62a includes a high pressure gas connection pipe 63a connected to the high and low pressure gas refrigerant communication pipe 8, a low pressure gas connection pipe 64a connected to the low pressure gas refrigerant communication pipe 9, and a high pressure gas connection pipe 63a and a low pressure gas connection. It has a merged gas connection pipe 65a that merges the pipe 64a. The merged gas connection pipe 65a is connected to the gas side of the use side heat exchanger 52a of the use side refrigerant circuit 13a. The high pressure gas connection pipe 63a is provided with a high pressure gas on / off valve 66a capable of opening / closing control, and the low pressure gas connection pipe 64a is provided with a low pressure gas on / off valve 67a capable of opening / closing control.

  When the use unit 3a performs the cooling operation, the connection unit 4a opens the low-pressure gas on / off valve 67a and allows the refrigerant flowing into the liquid connection pipe 61a through the liquid refrigerant communication pipe 7 to be used on the use-side refrigerant circuit. The refrigerant evaporated by heat exchange with the indoor air in the use side heat exchanger 52a through the use side flow rate adjustment valve 51a of 13a and through the combined gas connection pipe 65a and the low pressure gas connection pipe 64a is sent through the use side heat exchanger 52a. It can function to return to the low-pressure gas refrigerant communication tube 9. Further, the connection unit 4a closes the low pressure gas on / off valve 67a and opens the high pressure gas on / off 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 and the merged gas connection pipe 65a is sent to the use-side heat exchanger 52a of the use-side refrigerant circuit 13a, and the refrigerant radiated by heat exchange with room air in the use-side heat exchanger 52a is It can function to return to the liquid refrigerant communication pipe 7 through the use side flow rate adjustment valve 51a and the liquid connection pipe 61a. This function is provided not only by the connection unit 4a but also by the connection units 4b, 4c, and 4d. Can be switched individually to function as a refrigerant evaporator or radiator.

  Moreover, the connection unit 4a has the connection side control part 60a which controls operation | movement of each part 66a, 67a which comprises the connection unit 4a. The connection-side control unit 60a includes a microcomputer and a memory provided for controlling the connection 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 use side refrigerant circuits 13a, 13b, 13c, 13d, the heat source side refrigerant circuit 12, the refrigerant communication tubes 7, 8, 9 and the connection side refrigerant circuits 14a, 14b, 14c, 14d are connected. Thus, the refrigerant circuit 10 of the cooling and heating simultaneous operation type air conditioner 1 is configured. In the cooling and heating simultaneous operation type air conditioner 1, the refrigerant circuit 10 including the compressor 21, the heat source side heat exchangers 24 and 25, the receiver 28, and the use side heat exchangers 52a, 52b, 52c, and 52d is provided. The refrigeration apparatus which has is comprised. Here, as will be described later, the normal operation, which is the refrigeration cycle operation according to the heat load required from the use side heat exchangers 52a, 52b, 52c, 52d, and the suitability of the refrigerant amount in the refrigerant circuit 10 are determined. It is possible to switch and perform the refrigerant quantity determination operation which is a refrigeration cycle operation for determination. Here, as described above, the receiver bypass pipe 38 that bypasses the receiver 28 is connected to the refrigerant circuit 10, so that the refrigerant flows through the receiver bypass pipe 38 in the refrigerant amount determination operation described later. An operation for bypassing the receiver is performed.

(2) Operation | movement of freezing apparatus (cooling / heating simultaneous operation type air conditioning apparatus) Next, operation | movement of the cooling / heating simultaneous operation type air conditioning apparatus 1 is demonstrated.

  The operation mode of the cooling and heating simultaneous operation type air conditioner 1 roughly includes a normal operation mode which is a refrigeration cycle operation corresponding to a heat load required from the use side heat exchangers 52a, 52b, 52c and 52d, and a refrigerant circuit. 10 can be divided into a refrigerant amount determination operation mode that is a refrigeration cycle operation for determining the suitability of the refrigerant amount in the engine 10.

  The normal operation mode includes 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 In this operation, 24 and 25 are made to function as refrigerant radiators. 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 an operation for functioning 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 an operation to function 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. The operation is to function as an evaporator.

  The refrigerant quantity determination operation mode includes a refrigerant automatic charging operation and a refrigerant leakage detection operation. Here, in the refrigerant automatic charging operation, the refrigerant circuit 10 is operated until the refrigerant amount in the refrigerant circuit 10 reaches the target amount while performing the operation for stabilizing the state of the refrigerant circulating in the refrigerant circuit 10 (refrigerant amount determination operation). In this operation, the refrigerant is filled. The refrigerant leakage detection operation detects whether or not the refrigerant amount in the refrigerant circuit 10 satisfies the reference amount (that is, whether or not the refrigerant leaks from the refrigerant circuit 10 to the outside) while performing the refrigerant amount determination operation. Driving.

  In addition, operation | movement of the heating-and-cooling simultaneous operation type air conditioning apparatus 1 containing these operation modes is performed by said control part 20, 50a, 50b, 50c, 50d, 60a, 60b, 60c, 60d.

<Normal operation mode>
-Cooling operation-
During the cooling operation in the normal operation mode, for example, all of the usage units 3a, 3b, 3c, and 3d are in the cooling operation (that is, all of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant evaporator. When 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. 2 (for the refrigerant flow, (See arrow attached to refrigerant circuit 10 in FIG. 2).

  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. 2), and the second heat exchange switching mechanism The heat source side heat exchangers 24 and 25 are made to function as refrigerant radiators by switching the state 23 to the heat radiation operation state (the state indicated by the solid line of the second heat exchange switching mechanism 23 in FIG. 2). . Further, the high / low pressure switching mechanism 30 is switched to the evaporative load main operation state (the state indicated by the solid line of the high / low pressure switching mechanism 30 in FIG. 2). Further, the opening degree of the heat source side flow rate adjusting valves 26 and 27 as the heat source side flow rate adjusting mechanism is adjusted, and the receiver inlet on / off valve 28c is in an open state. Further, by closing the bypass-side flow rate adjustment valve 39 as the bypass-side flow rate adjustment mechanism, the refrigerant is allowed to flow through the receiver 28 without flowing the refrigerant through the receiver bypass pipe 38. In the connection units 4a, 4b, 4c and 4d, the use units 3a and 3b are opened by opening the high pressure gas on / off valves 66a, 66b, 66c and 66d and the low pressure gas on / off valves 67a, 67b, 67c and 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 usage-side flow rate adjustment valves 51a, 51b, 51c and 51d are adjusted in opening.

  In such a refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to 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 radiates 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. To do. The refrigerant that has radiated heat in the heat source side heat exchangers 24 and 25 is adjusted in flow rate in the heat source side flow rate adjusting valves 26 and 27, and then merges and passes through the inlet check valve 29a and the receiver inlet on / off valve 28c. Sent to. The refrigerant sent to the receiver 28 is temporarily stored in the receiver 28, and then passes through the receiver backflow prevention check valve 28 d, the outlet check valve 29 c, and the liquid side closing valve 31 as a receiver backflow prevention mechanism. And sent to the liquid refrigerant communication tube 7.

  And the refrigerant | coolant sent to the liquid refrigerant communication pipe | tube 7 is branched into four, and is sent to the liquid connection pipes 61a, 61b, 61c, 61d of each connection unit 4a, 4b, 4c, 4d. The refrigerant sent to the liquid connection pipes 61a, 61b, 61c, 61d is sent to the usage-side flow rate adjustment valves 51a, 51b, 51c, 51d of the usage units 3a, 3b, 3c, 3d.

  The refrigerant sent to the usage-side flow rate adjustment valves 51a, 51b, 51c, 51d is adjusted in flow rate at the usage-side flow rate adjustment valves 51a, 51b, 51c, 51d, and then used-side heat exchangers 52a, 52b, 52c. , 52d evaporates into a low-pressure gas refrigerant by exchanging heat with the indoor air supplied by the indoor fans 53a, 53b, 53c, 53d. 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. Then, the low-pressure gas refrigerant is sent to the merged gas connection pipes 65a, 65b, 65c, and 65d of the connection units 4a, 4b, 4c, and 4d.

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

  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 in the normal operation mode 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, and 52d becomes small, only one of the heat source side heat exchangers 24 and 25 (for example, the first heat source side heat exchanger 24) dissipates the refrigerant. The operation to function as a vessel is performed.

-Heating operation-
During the heating operation in the normal operation mode, for example, all of the usage units 3a, 3b, 3c, and 3d function as a heating operation (that is, all of the usage-side heat exchangers 52a, 52b, 52c, and 52d function as a refrigerant radiator). When the heat source side heat exchangers 24 and 25 function as a refrigerant evaporator, the refrigerant circuit 10 of the air conditioner 1 is configured as shown in FIG. (See arrow attached to refrigerant circuit 10 in FIG. 3).

  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. 3), and the second heat exchange switching mechanism is selected. The heat source side heat exchangers 24 and 25 are caused to function as refrigerant evaporators by switching the operation state to the evaporation operation state (the state indicated by the broken line of the second heat exchange switching mechanism 23 in FIG. 3). . Further, the high / low pressure switching mechanism 30 is switched to a heat radiation load main operation state (a state indicated by a broken line of the high / low pressure switching mechanism 30 in FIG. 3). Further, the opening degree of the heat source side flow rate adjusting valves 26 and 27 as the heat source side flow rate adjusting mechanism is adjusted, and the receiver inlet on / off valve 28c is in an open state. Further, by closing the bypass-side flow rate adjustment valve 39 as the bypass-side flow rate adjustment mechanism, the refrigerant is allowed to flow through the receiver 28 without flowing the refrigerant through the receiver bypass pipe 38. In the connection units 4a, 4b, 4c, and 4d, the high pressure gas on / off valves 66a, 66b, 66c, and 66d are opened, and the low pressure gas on / off 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 usage-side flow rate adjustment valves 51a, 51b, 51c and 51d are adjusted in opening.

  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 connection units 4a, 4b, 4c, 4d. It is done. The high-pressure gas refrigerant sent to the high-pressure gas connection pipes 63a, 63b, 63c, 63d passes through the high-pressure gas on / off valves 66a, 66b, 66c, 66d and the merged gas connection pipes 65a, 65b, 65c, 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 flow rate adjusting valves 51a, 51b, 51c, 51d, and then the liquid connection pipes of the connection units 4a, 4b, 4c, 4d. 61a, 61b, 61c and 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 the receiver 28 through the liquid side closing valve 31, the inlet check valve 29b, and the receiver inlet opening / closing valve 28c. After the refrigerant sent to the receiver 28 is temporarily stored in the receiver 28, the heat source side flow rate adjustment valve 26, through a receiver backflow prevention check valve 28d and an outlet check valve 29d as a receiver backflow prevention mechanism, 27 to both. The refrigerant sent to the heat source side flow rate adjustment valves 26, 27 is adjusted in flow rate in the heat source side flow rate adjustment valves 26, 27, and then is supplied to the outdoor source 34 by the outdoor fan 34 in the heat source side heat exchangers 24, 25. By evaporating with air, 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 and 23 merges and returns to the suction side of the compressor 21.

  In this way, the operation in the heating operation in the normal operation mode 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, only one of the heat source side heat exchangers 24, 25 (for example, the first heat source side heat exchanger 24) evaporates the refrigerant. The operation to function as a vessel is performed.

-Simultaneous cooling and heating operation (mainly evaporation load)-
During simultaneous cooling / heating operation (mainly evaporation load) in the normal operation mode, for example, the utilization units 3a, 3b, 3c are in cooling operation, and the utilization unit 3d is in heating operation (that is, utilization side heat exchangers 52a, 52b, 52c functions as a refrigerant evaporator, and the use side heat exchanger 52d functions as a refrigerant radiator), and the first heat source side heat exchanger 24 functions as a refrigerant radiator. The refrigerant circuit 10 of the harmony device 1 is configured as shown in FIG. 4 (see the arrows attached to the refrigerant circuit 10 of FIG. 4 for the refrigerant flow).

  Specifically, in the heat source unit 2, the first heat exchange switching mechanism 22 is switched to the heat dissipation operation state (the state indicated by the solid line of the first heat exchange switching mechanism 22 in FIG. 4), 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 main operation state (the state indicated by the broken line of the high / low pressure switching mechanism 30 in FIG. 4). Further, the opening degree of the first heat source side flow rate adjustment valve 26 as the heat source side flow rate adjustment mechanism is adjusted, and the second heat source side flow rate adjustment valve 27 as the heat source side flow rate adjustment mechanism is in a closed state, and the receiver inlet The on-off valve 28c is in an open state. Further, by closing the bypass-side flow rate adjustment valve 39 as the bypass-side flow rate adjustment mechanism, the refrigerant is allowed to flow through the receiver 28 without flowing the refrigerant through the receiver bypass pipe 38. In the connection units 4a, 4b, 4c, and 4d, the high-pressure gas on-off valve 66d and the low-pressure gas on-off valves 67a, 67b, and 67c are opened, and the high-pressure gas on-off valves 66a, 66b, 66c, and the low-pressure gas By closing the on-off 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 usage-side flow rate adjustment valves 51a, 51b, 51c and 51d are adjusted in opening.

  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 connection 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 on-off 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 radiated heat in the use side heat exchanger 52d is sent to the liquid connection pipe 61d of the connection unit 4d after the flow rate is adjusted in the use side flow rate adjustment valve 51d.

  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 that has radiated heat in the first heat source side heat exchanger 24 is adjusted in flow rate in the first heat source side flow rate adjustment valve 26 and then sent to the receiver 28 through the inlet check valve 29a and the receiver inlet opening / closing valve 28c. The refrigerant sent to the receiver 28 is temporarily stored in the receiver 28, and then passes through the receiver backflow prevention check valve 28 d, the outlet check valve 29 c, and the liquid side closing valve 31 as a receiver backflow prevention mechanism. And sent to the liquid refrigerant communication tube 7.

  The refrigerant radiated in the use side heat exchanger 52d and sent to the liquid connection pipe 61d is sent to the liquid refrigerant communication pipe 7 and radiated in the first heat source side heat exchanger 24 to be radiated. It merges with the refrigerant sent to.

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

  The refrigerant sent to the usage-side flow rate adjustment valves 51a, 51b, 51c is adjusted in flow rate at the usage-side flow rate adjustment valves 51a, 51b, 51c, and then the indoor fan in the usage-side heat exchangers 52a, 52b, 52c. By exchanging heat with the indoor air supplied by 53a, 53b, 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. Then, the low-pressure gas refrigerant is sent to the merged gas connection pipes 65a, 65b, and 65c of the connection units 4a, 4b, and 4c.

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

  Then, 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 gas-side closing valve 33.

  In this way, the operation in the simultaneous cooling / heating operation (mainly the evaporation load) in the normal operation mode 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 (mainly heat radiation load)-
During simultaneous cooling / heating operation (mainly heat radiation load) in the normal operation mode, for example, the usage units 3a, 3b, 3c perform heating operation, and the usage unit 3d performs cooling operation (that is, usage-side heat exchangers 52a, 52b, 52c functions as a refrigerant radiator and the use side heat exchanger 52d functions as a refrigerant evaporator), and only the first heat source side heat exchanger 24 functions as a refrigerant evaporator. The refrigerant circuit 10 of the air conditioner 1 is configured as shown in FIG. 5 (see the arrows attached to the refrigerant circuit 10 in FIG. 5 for the refrigerant flow).

  Specifically, in the heat source unit 2, by switching the first heat exchange switching mechanism 22 to the evaporation operation state (the state indicated by the broken line of the first heat exchange switching mechanism 22 in FIG. 5), the first heat source switching mechanism 22 Only the heat exchanger 24 functions as a refrigerant evaporator. Moreover, the high / low pressure switching mechanism 30 is switched to the heat radiation load main operation state (the state indicated by the broken line of the high / low pressure switching mechanism 30 in FIG. 5). Further, the opening degree of the first heat source side flow rate adjustment valve 26 as the heat source side flow rate adjustment mechanism is adjusted, and the second heat source side flow rate adjustment valve 27 as the heat source side flow rate adjustment mechanism is in a closed state, and the receiver inlet The on-off valve 28c is in an open state. Further, by closing the bypass-side flow rate adjustment valve 39 as the bypass-side flow rate adjustment mechanism, the refrigerant is allowed to flow through the receiver 28 without flowing the refrigerant through the receiver bypass pipe 38. In the connection units 4a, 4b, 4c and 4d, the high pressure gas on / off valves 66a, 66b and 66c and the low pressure gas on / off valve 67d are opened, and the high pressure gas on / off valve 66d and the low pressure gas on / off valve 67a, 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 usage-side flow rate adjustment valves 51a, 51b, 51c and 51d are adjusted in opening.

  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 three and sent to the high-pressure gas connection pipes 63a, 63b, 63c of the connection units 4a, 4b, 4c. The high-pressure gas refrigerant sent to the high-pressure gas connection pipes 63a, 63b, and 63c passes through the high-pressure gas on / off valves 66a, 66b, and 66c and the merged gas connection pipes 65a, 65b, and 65c, and the use side of the use units 3a, 3b, and 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 dissipated heat in the usage-side heat exchangers 52a, 52b, and 52c is adjusted in flow rate in the usage-side flow rate adjustment valves 51a, 51b, and 51c, and then into the liquid connection pipes 61a, 61b, and 61c of the connection units 4a, 4b, and 4c. Sent.

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

  A part of the refrigerant merged in the liquid refrigerant communication pipe 7 is sent to the liquid connection pipe 61d of the connection unit 4d, and the rest passes through the liquid side closing valve 31, the inlet check valve 29b, and the receiver inlet opening / closing valve 28c. It is sent to the receiver 28.

  The refrigerant sent to the liquid connection pipe 61d of the connection unit 4d is sent to the usage-side flow rate adjustment valve 51d of the usage unit 3d.

  The refrigerant sent to the use-side flow rate adjustment valve 51d is subjected to heat exchange with the 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 flow rate adjustment valve 51d. As a result, it 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. Then, the low-pressure gas refrigerant is sent to the merged gas connection pipe 65d of the connection 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 on-off valve 67d and the low-pressure gas connection pipe 64d.

  Then, 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 gas-side closing valve 33.

  The refrigerant sent to the receiver 28 is temporarily stored in the receiver 28 and then flows through the first heat source side flow rate through the receiver backflow prevention check valve 28d and the outlet check valve 29d as a receiver backflow prevention mechanism. It is sent to the control valve 26. The refrigerant sent to the first heat source side flow rate adjustment valve 26 is adjusted in flow rate in the first heat source side flow rate adjustment valve 26, and then is supplied to the outdoor side supplied by the outdoor fan 34 in the first heat source side heat exchanger 24. By evaporating with air, it evaporates into a low-pressure gas refrigerant and is sent to the first heat exchange switching mechanism 22. The low-pressure gas refrigerant sent to the first heat exchange switching mechanism 22 merges with the low-pressure gas refrigerant returned to the suction side of the compressor 21 through the low-pressure gas refrigerant communication tube 9 and the gas-side shut-off valve 33, 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) in the normal operation mode 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 second heat source side heat exchanger 25 to function as a refrigerant radiator, the evaporation load of the first heat source side heat exchanger 24 and the heat radiation 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.

<Refrigerant amount judgment operation mode>
-Automatic refrigerant charging operation-
First, the operation | movement in the refrigerant | coolant automatic filling driving | operation of refrigerant | coolant amount determination operation mode is demonstrated using FIGS. Here, FIG. 6 is a flowchart of the automatic refrigerant charging operation. FIG. 7 is a diagram illustrating an operation (refrigerant flow) in the refrigerant automatic charging operation in the refrigerant quantity determination operation mode. FIG. 8 is a graph showing the relationship between the degree of refrigerant subcooling on the liquid side of the heat source side heat exchangers 24 and 25 and the amount of refrigerant in the refrigerant circuit 10 in the refrigerant quantity determination operation.

  Here, at the site, the heat source unit 2 preliminarily filled with the refrigerant, the utilization units 3a, 3b, 3c, and 3d and the connection units 4a, 4b, 4c, and 4d are connected via the refrigerant communication tubes 7, 8, and 9, respectively. After the refrigerant circuit 10 is connected and configured, an example in which the refrigerant circuit 10 is additionally filled with a refrigerant that is insufficient according to the length of the refrigerant communication tubes 7, 8, 9 will be described.

  First, the shut-off valves 31, 32, 33 of the heat source unit 2 are opened, and the refrigerant previously filled in the heat source unit 2 is filled in the refrigerant circuit 10.

  Next, when a service person or the like issues a command to perform the refrigerant automatic charging operation in the refrigerant amount determination operation mode through the remote controller (not shown) or the control unit 20, 50a, 50b, 50c, 50d, etc. The refrigerant automatic charging operation is performed in the procedure from step S11 to step S14.

  When the start command for the automatic refrigerant charging operation is issued, the refrigerant amount determination operation in step S11 is started. In this refrigerant amount determination operation, as in the cooling operation in the normal operation mode (see FIG. 2), all of the usage units 3a, 3b, 3c, and 3d are in the cooling operation (that is, the usage-side heat exchangers 52a, 52b, 52c, 52d performs an operation in which all functions as a refrigerant evaporator), and heat source side heat exchangers 24 and 25 perform an operation in which they function as a refrigerant radiator.

  However, in the refrigerant quantity determination operation, unlike the cooling operation in the normal operation mode, the following device control is performed to mainly stabilize the state of the refrigerant circulating in the refrigerant circuit 10. Specifically, the rotational speed of the outdoor fan 34 is controlled so that the high pressure in the refrigerant circuit 10 (here, the pressure of the refrigerant detected by the discharge pressure sensor 73) becomes the target high pressure (hereinafter referred to as “high pressure control”). ”). Further, the operating capacity of the compressor 21 is controlled so that the low pressure in the refrigerant circuit 10 (here, the refrigerant pressure detected by the suction pressure sensor 71 is used) becomes the target low pressure (hereinafter referred to as “low pressure control”). )doing. Further, the degree of superheat of the refrigerant in the portion from the gas side of the use side heat exchangers 52a, 52b, 52c, 52d to the suction side of the compressor 21 (here, the refrigerant pressure detected by the suction pressure sensor 71 is the saturation of the refrigerant). The temperature of the use side flow rate adjustment mechanisms 51a, 51b, 51c, 51d is adjusted so that the temperature becomes the target superheat degree by using the temperature difference obtained by subtracting the refrigerant temperature detected by the suction temperature sensor 72 from the saturation temperature. The opening degree is controlled (hereinafter referred to as “superheat degree control”). Further, the bypass-side flow rate adjustment valve 39 as the bypass-side flow rate adjustment mechanism is controlled (hereinafter referred to as “receiver bypass control”) so as to cause the refrigerant to flow through the receiver bypass pipe 38 and bypass the receiver 28. Here, the reason why the high pressure control is performed is that the amount of refrigerant in the high pressure portion of the refrigerant circuit 10 (for example, the heat source side heat exchangers 24 and 25 and the liquid refrigerant communication pipe 7) greatly affects the high pressure in the refrigerant circuit 10. It is. The low pressure control and the superheat control are performed because the amount of refrigerant in the low pressure portion of the refrigerant circuit 10 (for example, the use side heat exchangers 52a, 52b, 52c, 52d and the gas refrigerant communication pipes 8, 9) is reduced. This is because it greatly affects the low pressure in the circuit 10 and the dryness of the refrigerant. Furthermore, the reason why the receiver bypass control is performed is that, in the refrigerant circuit 10 having the receiver 28, how much refrigerant amount exists in the receiver 28 greatly affects the error at the time of refrigerant amount determination. That is, by performing high-pressure control, low-pressure control, and superheat degree control, the state of the refrigerant circulating in the refrigerant circuit 10 is substantially stabilized, whereby the change in the amount of refrigerant in the refrigerant circuit 10 is caused by heat source side heat exchange. The degree of supercooling of the refrigerant on the liquid side of the vessels 24 and 25 (here, the refrigerant pressure detected by the discharge pressure sensor 73 is converted into the refrigerant saturation temperature, and this saturation temperature is detected by the liquid side temperature sensor 74. However, if the refrigerant is introduced into the receiver 28, a change in the amount of refrigerant in the receiver 28 occurs and the refrigerant amount changes. This is because the degree of supercooling does not change appropriately. On the other hand, it is conceivable to keep the receiver liquid level constant as in the conventional case, but it is necessary to provide the liquid level detection means on the receiver 28, and when the liquid level detection tube is used as the liquid level detection means In some cases, it may be difficult to obtain sufficient accuracy, and it is difficult to keep the liquid level of the receiver 28 constant. As a result, a situation in which the degree of supercooling of the refrigerant does not change appropriately occurs. .

  Therefore, here, in order to obtain a situation where the state of the refrigerant circulating in the refrigerant circuit 10 is stabilized and the degree of supercooling of the refrigerant changes appropriately, the receiver bypass is combined with the high pressure control, the low pressure control, and the superheat degree control. Control is performed. The receiver bypass control mainly causes the refrigerant to flow through the receiver bypass pipe 38 to bypass the receiver 28. Specifically, control is performed to open a bypass-side flow rate adjustment valve 39 as a bypass-side flow rate adjustment mechanism provided in the receiver bypass pipe 38. In addition to the control for opening the bypass side flow rate adjustment valve 39, the control for closing the heat source side flow rate adjustment valves 26 and 27 as the heat source side flow rate adjustment mechanism is performed. Further, control is performed to open the receiver gas vent flow control valve 42 as the receiver gas vent flow control mechanism provided in the receiver gas vent pipe 41. As a result, as shown in FIG. 7, the refrigerant is not allowed to flow through the receiver 28 by the receiver bypass pipe 38, and the cooling operation is performed in a state where the receiver 28 is disconnected from the refrigerant circuit 10 (that is, the refrigerant is not introduced into the receiver 28). Will be done. In addition, since the receiver outlet pipe 28b is provided with a receiver backflow prevention check valve 28d as a receiver backflow prevention mechanism, the refrigerant bypassing the receiver 28 through the receiver bypass pipe 38 may flow into the receiver 28. It is suppressed. Furthermore, by opening the receiver gas vent flow control valve 42 as the receiver gas vent flow control mechanism, the liquid refrigerant present in the receiver 28 evaporates under reduced pressure and is extracted to the suction side of the compressor 21. 28 approaches an empty state.

  While performing the refrigerant amount determination operation with the control for stabilizing the state of the refrigerant circulating in the refrigerant circuit 10 as described above, the refrigerant circuit 10 is additionally charged in the refrigerant circuit 10 in step S12. Here, the additional charging of the refrigerant is performed by connecting a refrigerant cylinder or the like to the charging nozzle 21b provided on the suction side of the compressor 21, as shown in FIG.

  After the refrigerant charging in step S12 is started, the degree of refrigerant subcooling on the liquid side of the heat source side heat exchangers 24 and 25 is detected, and in step S13, the refrigerant amount in the refrigerant circuit 10 shown in FIG. It is determined whether or not the refrigerant subcooling target value SCt corresponding to the target amount Mt has been reached (appropriateness of the refrigerant amount in the refrigerant circuit 10). Specifically, when the amount of refrigerant to be additionally charged is small and the amount of refrigerant has not reached the target amount Mt, the degree of supercooling of the refrigerant becomes smaller than the target value SCt, but the additional charging of refrigerant proceeds. As a result, the degree of supercooling of the refrigerant increases. In step S13, the processes in steps S12 and S13 are repeated until the degree of refrigerant supercooling reaches the target value SCt (that is, until the refrigerant amount reaches the target value Mt in the refrigerant circuit 10).

  If it is determined in step S13 that the target amount Mt of the refrigerant amount in the refrigerant circuit 10 has been reached, the process proceeds to step S14 and the additional charging of the refrigerant is terminated.

  In this way, the operation in the refrigerant automatic charging operation in the refrigerant quantity determination operation mode is performed.

-Refrigerant leak detection operation-
Next, the operation in the refrigerant leakage detection operation in the refrigerant amount determination operation mode will be described with reference to FIGS. Here, FIG. 9 is a flowchart of the refrigerant leakage detection operation in the refrigerant quantity determination operation mode. FIG. 10 is a diagram illustrating an operation (refrigerant flow) in the refrigerant leak detection and charging operation in the refrigerant amount determination operation mode.

  Here, it is determined whether or not the amount of refrigerant in the refrigerant circuit 10 satisfies the reference amount after the various operations in the normal operation mode are performed for a predetermined time (that is, whether or not the refrigerant leaks from the refrigerant circuit 10 to the outside). The case of detection will be described as an example.

  First, when a service person or the like issues a command to perform the refrigerant leakage detection operation in the refrigerant quantity determination operation mode through the remote controller (not shown), the control unit 20, 50a, 50b, 50c, 50d, or the like (step S21). The refrigerant leakage detection operation is performed in the following steps S22 to S25.

  Next, when an instruction to start the refrigerant leakage detection operation is made, the refrigerant amount determination operation in step S22 is started. This refrigerant amount determination operation is the same operation as the refrigerant amount determination operation in step S11 of the automatic refrigerant charging operation. That is, as shown in FIG. 10, all of the usage units 3a, 3b, 3c, and 3d are in the cooling operation (that is, the usage-side heat exchangers 52a, 52b, 52c, and 52d all function as a refrigerant evaporator). The heat source side heat exchangers 24 and 25 perform an operation of functioning as a refrigerant radiator, and perform receiver bypass control together with high pressure control, low pressure control, and superheat degree control. As a result, as in the automatic refrigerant charging operation, the state of the refrigerant circulating in the refrigerant circuit 10 is stabilized, and a situation in which the degree of subcooling of the refrigerant appropriately changes can be obtained.

  While performing the refrigerant amount determination operation with the control for stabilizing the state of the refrigerant circulating in the refrigerant circuit 10 as described above, the degree of refrigerant subcooling on the liquid side of the heat source side heat exchangers 24 and 25 is detected, In step S23, whether or not the reference amount Ms of the refrigerant amount in the refrigerant circuit 10 shown in FIG. 8 (for example, the target amount Mt of the refrigerant amount during the automatic refrigerant charging operation) is satisfied (propriety of the refrigerant amount in the refrigerant circuit 10). Determine. Specifically, when the refrigerant does not leak from the refrigerant circuit 10 to the outside, the degree of supercooling of the refrigerant becomes substantially the same as the reference value SCs of the degree of supercooling corresponding to the reference amount Ms of the refrigerant amount. When the refrigerant leaks from the refrigerant circuit 10 to the outside, the degree of supercooling of the refrigerant becomes smaller than the reference value SCs.

  If it is determined in step S23 that the reference amount Ms of the refrigerant amount in the refrigerant circuit 10 is satisfied, the return processing to the normal operation mode in step S24 is performed, and the reference amount of the refrigerant amount in the refrigerant circuit 10 is determined. If it is determined that Ms is not satisfied, the process proceeds to step S25, and the fact that the refrigerant has leaked is indicated to the remote controller (not shown), the control unit 20, 50a, 50b, 50c, 50d, or the like. A warning is displayed, and the process of returning to the normal operation mode in step S24 is performed. In the return processing to the normal operation mode in step S24, control for opening the heat source side flow rate adjustment valves 26 and 27 as the heat source side flow rate adjustment mechanism and control for closing the bypass side flow rate adjustment valve 39 as the bypass side flow rate adjustment mechanism are performed. Thus, the refrigerant is switched to flow through the receiver 28 without flowing through the receiver bypass pipe 38 (that is, the state where the refrigerant is not introduced into the receiver 28 is canceled). And it returns to various driving | operations of a normal driving | operation mode as shown in FIGS.

  In this way, the operation in the refrigerant leakage detection operation in the refrigerant quantity determination operation mode is performed.

  The refrigerant leakage detection operation is set in the remote controller (not shown), the control unit 20 or the like so that the refrigerant leakage detection operation is executed periodically, for example, once every two months. When it becomes, you may make it drive | work automatically.

(3) Features of the refrigeration apparatus (cooling / heating simultaneous operation type air conditioner) The cooling / heating simultaneous operation type air conditioner 1 has the following characteristics.

<A>
Here, as described above, it is possible to prevent the refrigerant from flowing into the receiver 28 by the receiver bypass pipe 38 during the refrigerant quantity determination operation (FIGS. 7 and 10). For this reason, it is possible to determine the suitability of the refrigerant amount in the refrigerant circuit 10 in a state where the receiver 28 is disconnected from the refrigerant circuit 10 (that is, a state where no refrigerant is introduced into the receiver 28). Thereby, the error at the time of refrigerant quantity determination can be made small here.

<B>
Here, as described above, it is possible to prevent the refrigerant bypassing the receiver 28 from flowing into the receiver 28 by the receiver backflow prevention check valve 28d as the receiver backflow prevention mechanism. That is, during the refrigerant quantity determination operation, the refrigerant flows into the receiver outlet pipe 28b from the liquid side of the heat source side heat exchangers 24 and 25 through the receiver bypass pipe 38. The refrigerant flowing into the receiver outlet pipe 28b is received by the receiver. 28 is prevented from flowing back into the receiver 28 from the outlet. Thereby, the state which disconnected the receiver 28 from the refrigerant circuit 10 at the time of a refrigerant | coolant amount determination driving | operation can be maintained here.

<C>
Here, as described above, the receiver bypass pipe 38 branches from a portion between the heat source side heat exchangers 24 and 25 of the refrigerant circuit 10 and the heat source side flow rate adjustment valves 26 and 27 as the heat source side flow rate adjustment mechanism. Therefore, the refrigerant that has passed through the heat source side heat exchangers 24 and 25 is guided to the receiver 28 by opening the heat source side flow rate adjusting valves 26 and 27 during normal operation, and the heat source side flow rate adjustment during refrigerant amount determination operation. By closing the valves 26 and 27, the refrigerant that has passed through the heat source side heat exchangers 24 and 25 can be guided to the receiver bypass pipe 38 to bypass the receiver 28. Thereby, here, the receiver 28 can be surely switched to a state in which the receiver 28 is disconnected from the refrigerant circuit 10 when shifting from the normal operation to the refrigerant amount determination operation.

<D>
Here, as described above, the receiver bypass pipe 38 is provided with the bypass-side flow rate adjustment valve 39 as a bypass-side flow rate adjustment mechanism. Therefore, by closing the bypass-side flow rate adjustment valve 39 during normal operation, The refrigerant that has passed through the heat exchangers 24 and 25 is prevented from bypassing the receiver 28, and the refrigerant that has passed through the heat source side heat exchangers 24 and 25 is opened by opening the bypass side flow rate adjustment valve 39 during the refrigerant amount determination operation. 38 to bypass the receiver 28. Thereby, here, when returning from the refrigerant quantity determination operation to the normal operation, it is possible to surely switch to the state in which the receiver 28 is used.

<E>
Here, as described above, the check valves 40a and 40b for bypass backflow prevention as the bypass backflow prevention mechanism are provided on the upstream side of the bypass side flow control valve 39 as the bypass side flow control mechanism of the receiver bypass pipe 38. Therefore, it is possible to prevent the refrigerant from flowing back through the receiver bypass pipe 38 in a state where the bypass-side flow rate adjustment valve 39 is opened. For example, at the time of transition from the normal operation to the refrigerant amount determination operation, when both the heat source side flow rate adjustment valves 26 and 27 and the bypass side flow rate adjustment valve 39 as the heat source side flow rate adjustment mechanism are opened, Depending on the pressure difference between the receiver outlet pipe 28b and the liquid side of the heat source side heat exchangers 24 and 25, the refrigerant may flow back through the receiver bypass pipe 38. However, the check valves 40a and 40b for preventing the backflow of the bypass Such a backflow can be suppressed.

<F>
Here, as described above, the receiver bypass pipe 38 is provided with the liquid seal prevention pipe 38d that bypasses the bypass backflow prevention check valves 40a and 40b as the bypass backflow prevention mechanism. In a state in which the bypass side flow rate adjustment valve 39 is closed, liquid sealing at a portion between the bypass backflow prevention check valves 40 a and 40 b and the bypass side flow rate adjustment valve 39 of the receiver bypass pipe 38 can be prevented. For example, in normal operation, since the bypass-side flow rate adjustment valve 39 is closed, the portion of the receiver bypass pipe 38 between the bypass backflow prevention check valves 40a and 40b and the bypass-side flow rate adjustment valve 39 is liquid. Although there is a risk of sealing, such liquid sealing can be prevented by the liquid sealing prevention tube 38d.

<G>
Here, since the receiver degassing pipe 41 is connected to the receiver 28 as described above, the liquid refrigerant present in the receiver 28 is evaporated under reduced pressure during the refrigerant amount determination operation so that the suction side of the compressor 21 The receiver 28 can be extracted and brought close to an empty state. Thereby, the error at the time of refrigerant quantity determination can be made still smaller here. In particular, as described above, the receiver 28 is separated from the refrigerant circuit 10 by the receiver bypass pipe 38 (that is, the refrigerant is not introduced into the receiver 28). The receiver 28 can be brought close to an empty state without hindering the circulation of the refrigerant in the inside 10.

(4) Modifications In the above embodiment, the configuration example of the cooling and heating simultaneous operation type air conditioner 1 is described as a refrigeration apparatus to which the present invention is applied. However, the present invention is not limited to this. That is, even a cooling / heating switching operation type or a cooling operation dedicated type air conditioner has a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver, and a use side heat exchanger, and the use side Switching between normal operation, which is a refrigeration cycle operation according to the heat load required from the heat exchanger, and refrigerant amount determination operation, which is a refrigeration cycle operation for determining the suitability of the refrigerant amount in the refrigerant circuit, can be performed. If possible, the present invention can be applied.

  Moreover, in said embodiment, although the structure where the heat source side heat exchanger was divided | segmented into the two heat source side heat exchangers 24 and 25 is employ | adopted, it does not need to be a division structure. In this case, only one heat source side flow rate adjusting valve as the heat source side flow rate adjusting mechanism or one bypass branch pipe of the receiver bypass pipe 38 is required.

  The present invention has a refrigerant circuit including a compressor, a heat source side heat exchanger, a receiver, and a use side heat exchanger, and is a refrigeration cycle operation according to a heat load required from the use side heat exchanger. The present invention can be widely applied to a refrigeration apparatus capable of switching between a normal operation and a refrigerant amount determination operation that is a refrigeration cycle operation for determining the suitability of the refrigerant amount in the refrigerant circuit.

1 Cooling and heating simultaneous operation type air conditioner (refrigeration equipment)
DESCRIPTION OF SYMBOLS 10 Refrigerant circuit 21 Compressor 24, 25 Heat source side heat exchanger 26, 27 Heat source side flow control valve (heat source side flow control mechanism)
28 Receiver 28d Receiver backflow prevention check valve (Receiver backflow prevention mechanism)
38 Receiver bypass pipe 38d Liquid seal prevention pipe 39 Bypass side flow control valve (Bypass side flow control mechanism)
40a, 40b Bypass backflow prevention check valve (bypass backflow prevention mechanism)
41 Receiver degassing pipe 52a-52d Use side heat exchanger

JP 2006-292212 A

Claims (7)

It has a refrigerant circuit (10) including a compressor (21), a heat source side heat exchanger (24, 25), a receiver (28), and a use side heat exchanger (52a, 52b, 52c, 52d). A refrigerant amount determination operation that is a normal operation that is a refrigeration cycle operation according to a heat load required from the use-side heat exchanger, and a refrigeration cycle operation that determines the suitability of the refrigerant amount in the refrigerant circuit. In a refrigeration system that can be switched between
A receiver bypass pipe (38) for bypassing the receiver is connected to the refrigerant circuit;
In the refrigerant amount determination operation, the refrigerant is caused to flow through the receiver bypass pipe to bypass the receiver.
Refrigeration equipment (1). The refrigerant circuit (10) is provided with a receiver backflow prevention mechanism (28d) that suppresses the refrigerant bypassing the receiver (28) through the receiver bypass pipe (38) from flowing into the receiver.
The refrigeration apparatus (1) according to claim 1. The refrigerant circuit (10) is provided with a heat source side flow rate adjusting mechanism (26, 27) for adjusting the flow rate of the refrigerant flowing through the heat source side heat exchanger (24, 25),
The receiver bypass pipe (38) is connected to the refrigerant circuit (10) so as to branch from a portion between the heat source side heat exchanger and the heat source side flow rate adjustment mechanism of the refrigerant circuit.
The refrigeration apparatus (1) according to claim 1 or 2. The receiver bypass pipe (38) has a bypass side flow rate adjustment mechanism (39) for adjusting the flow rate of the refrigerant flowing through the receiver bypass pipe.
The refrigeration apparatus (1) according to any one of claims 1 to 3. The receiver bypass pipe (38) is provided with a bypass backflow prevention mechanism (40a, 40b) for suppressing a backflow of the refrigerant from the bypass side flow rate adjustment mechanism side at a portion upstream of the bypass side flow rate adjustment mechanism (39). Have
The refrigeration apparatus (1) according to claim 4. The receiver bypass pipe (38) includes a liquid seal prevention pipe (38d) that bypasses the bypass backflow prevention mechanism (40a, 40b).
The refrigeration apparatus (1) according to claim 5. The receiver (28) is connected to a receiver degassing pipe (41) that connects the upper part of the receiver and the suction side of the compressor (21).
The refrigeration apparatus (1) according to any one of claims 1 to 6.

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