JP3963192B1 - Air conditioner - Google Patents

Abstract

An object of the present invention is to reduce the pressure of a high-pressure gas pipe and prevent liquid refrigerant from being accumulated in the high-pressure gas pipe due to condensation.
An air conditioner 1 is an air conditioner that performs a refrigerant amount determination operation for determining a refrigerant amount in a refrigerant circuit 10, and includes a heat source unit 2, use units 3a to 3c, and expansion mechanisms V2, V9a. V9c, first refrigerant gas pipe 52, second refrigerant gas pipe 53, refrigerant liquid pipe 51, switching mechanisms 4a to 4c, bypass circuits 27, 43a to 43c, and bypass circuit opening / closing means V3 and V13a to V13c and the control part 8 are provided. The switching mechanism can switch between the first state and the second state. The bypass circuit opening / closing means is provided on a bypass circuit that bypasses the first refrigerant gas pipe and the second refrigerant gas pipe, and opens and closes the bypass circuit. The control unit opens the bypass circuit opening / closing means before performing the refrigerant quantity determination operation.
[Selection] Figure 1

Description

  The present invention relates to a refrigerant circuit of an air conditioner and an air conditioner including the refrigerant circuit.

Conventionally, in order to determine whether the amount of refrigerant in the refrigerant circuit of the air conditioner is excessive or insufficient, a method of simulating refrigeration cycle characteristics and using this calculation result to determine whether the amount of refrigerant is excessive or insufficient has been proposed. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 3-186170

However, in the technology of Patent Document 1, in the multi-air conditioner capable of simultaneous cooling and heating, when performing the refrigerant amount determination operation in the all-room cooling operation, the high-pressure gas pipe extending from the outdoor unit to the cooling / heating selection unit is on the cooling / heating selection unit side. Therefore, the refrigerant is condensed and accumulated in the pipe, which may increase the detection error.
An object of the present invention is to make a high-pressure gas pipe low in a refrigerant amount determination operation of a multi-air conditioner capable of simultaneous cooling and heating, and to prevent liquid refrigerant from being accumulated in the high-pressure gas pipe due to condensation.

  An air conditioner according to a first aspect of the present invention is an air conditioner that performs a refrigerant amount determination operation for determining a refrigerant amount in a refrigerant circuit, and includes a heat source unit, a utilization unit, an expansion mechanism, and a first gas refrigerant pipe. , A second gas refrigerant pipe, a liquid refrigerant pipe, a switching mechanism, a bypass circuit, a bypass circuit opening / closing means, and a control unit. The heat source unit includes a compression means for compressing the refrigerant gas and a heat source side heat exchanger. The utilization unit has a utilization side heat exchanger. The first gas refrigerant pipe extends from the discharge side of the compression means to the utilization unit. The second gas refrigerant pipe extends from the suction side of the compression means to the utilization unit. The liquid refrigerant pipe extends from the heat source side heat exchanger to the utilization unit. The switching mechanism can switch between the first state and the second state. The first state is a state in which the refrigerant flowing in the liquid refrigerant pipe is evaporated in the use side heat exchanger and then flows into the second gas refrigerant pipe. The second state is a state in which the refrigerant flowing through the first gas refrigerant pipe flows into the liquid refrigerant pipe after being condensed in the use side heat exchanger. The bypass circuit bypasses the first gas refrigerant pipe and the second gas refrigerant pipe. The bypass circuit opening / closing means is provided on the bypass circuit and opens and closes the bypass circuit. The control unit opens the bypass circuit opening / closing means before performing the refrigerant quantity determination operation.

  This air conditioner has two lines of refrigerant piping, and the switching mechanism can freely set the cooling operation and the heating operation by switching between the first state (cooling state) and the second state (heating state). It is. In this air conditioning apparatus capable of simultaneous cooling and heating, for example, the refrigerant quantity determination operation is performed by setting all the rooms (all the utilization units) to the first state (cooling state) in the switching mechanism (cooling / heating selection unit). Since the first gas refrigerant pipe (high-pressure gas pipe) extending from the unit to the switching mechanism is closed, there is a risk that the refrigerant will condense and accumulate in the pipe, increasing detection errors.

  Therefore, in the present invention, a bypass circuit opening / closing means (bypass valve) for bypassing the first gas refrigerant pipe and the second gas refrigerant pipe is provided, and the bypass circuit opening / closing means (bypass valve) is opened during the refrigerant amount determination operation. By doing so, the pressure difference between the first gas refrigerant pipe and the second gas refrigerant pipe is reduced, and the accumulation of liquid refrigerant due to condensation in the first gas refrigerant pipe is prevented. For this reason, highly accurate refrigerant quantity determination operation becomes possible.

An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the bypass circuit opening / closing means is provided in the heat source unit.
In this air conditioner, the bypass circuit opening / closing means is provided in the heat source unit. Therefore, the bypass circuit can be provided in the refrigerant circuit without performing piping work for the bypass circuit at the time of construction. For this reason, the effort and cost concerning construction can be reduced.

An air conditioner according to a third aspect of the present invention is the air conditioner according to the first or second aspect of the present invention, further comprising a switching unit. The switching unit is a unit different from the heat source unit and the utilization unit. The switching unit has a switching mechanism. The bypass circuit opening / closing means is provided in the switching unit.
In this air conditioner, a bypass circuit opening / closing means is provided in the switching unit. The refrigerant hardly flows through the first gas refrigerant pipe only by providing the bypass circuit opening / closing means in the heat source unit. For this reason, the temperature of the gas refrigerant in the pipe changes due to the inflow heat from the outside air, the refrigerant density may change, and the detection error may increase.

  Therefore, in the present invention, a bypass circuit opening / closing means for bypassing the first gas refrigerant pipe and the second gas refrigerant pipe is provided in the switching unit, and by using this together, a low-pressure gas refrigerant is introduced into the first gas refrigerant pipe. It makes it easy to flow. For this reason, it can suppress that the gas refrigerant in a pipe changes in temperature by the inflow heat from outside air, and can reduce a detection error. In addition, the bypass circuit can be provided in the refrigerant circuit without performing piping work for the bypass circuit at the time of construction. For this reason, the effort and cost concerning construction can be reduced.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to any of the first to third aspects of the present invention, further comprising a temperature detecting means. The temperature detecting means detects a refrigerant temperature in the first gas refrigerant pipe and outputs a refrigerant temperature detection value. The control unit corrects the determined refrigerant amount determined by the refrigerant amount determination operation based on the refrigerant temperature detection value.
In this air conditioner, by providing a bypass circuit, the first gas refrigerant pipe bypasses the first gas refrigerant pipe and the second gas refrigerant pipe, and the refrigerant gas pressure distribution in the pipe is equalized. Is difficult to flow. For this reason, the temperature of the gas refrigerant in the pipe changes due to the inflow heat from the outside air, the refrigerant density may change, and the detection error may increase.
Therefore, in the present invention, the detection error can be reduced by providing temperature detection means in the first gas refrigerant pipe and correcting the refrigerant density in the pipe using the refrigerant temperature detection value. For this reason, more accurate refrigerant quantity determination operation is possible.

An air conditioner according to a fifth aspect is the air conditioner according to the fourth aspect, wherein the temperature detecting means is provided in the switching unit.
This air conditioner is provided with temperature detection means on the first gas refrigerant pipe in the switching unit. Therefore, at the time of construction, the temperature detecting means can be provided on the first gas refrigerant pipe without providing the temperature detecting means on the refrigerant communication pipe. For this reason, the effort and cost concerning construction can be reduced.

  An air conditioner according to a sixth aspect of the present invention is the air conditioner according to the fourth or fifth aspect of the present invention, wherein the temperature detection device is provided in the heat source unit.

  This air conditioner is provided with temperature detecting means on the first gas refrigerant pipe in the heat source unit. Therefore, at the time of construction, the temperature detecting means can be provided on the first gas refrigerant pipe without providing the temperature detecting means on the refrigerant communication pipe. For this reason, the effort and cost concerning construction can be reduced. Moreover, by using together with the temperature detection means in the switching unit of the fifth invention, the refrigerant density in the pipe can be corrected with higher accuracy.

  In the air conditioner according to the first aspect of the present invention, a bypass circuit opening / closing means (bypass valve) for bypassing the first gas refrigerant pipe and the second gas refrigerant pipe is provided, and the bypass circuit opening / closing means is opened during the refrigerant amount determination operation. By doing so, the pressure difference between the first gas refrigerant pipe and the second gas refrigerant pipe is reduced, and the accumulation of liquid refrigerant due to condensation in the first gas refrigerant pipe is prevented. For this reason, highly accurate refrigerant quantity determination operation becomes possible.

In the air conditioner according to the second aspect of the present invention, the bypass circuit can be provided in the refrigerant circuit without performing bypass piping work during construction. For this reason, the effort and cost concerning construction can be reduced.
In the air conditioner according to the third aspect of the present invention, a bypass circuit opening / closing means for bypassing the first gas refrigerant pipe and the second gas refrigerant pipe is provided in the switching unit, and by using this together, the first gas refrigerant pipe is provided in the first gas refrigerant pipe. The low-pressure gas refrigerant is easy to flow. For this reason, it can suppress that the gas refrigerant in a pipe changes in temperature by the inflow heat from outside air, and can reduce a detection error. In addition, the bypass circuit can be provided in the refrigerant circuit without performing piping work for the bypass circuit at the time of construction. For this reason, the effort and cost concerning construction can be reduced.

In the air conditioner according to the fourth aspect of the invention, the temperature detection means is provided in the first gas refrigerant pipe, and the detection error can be reduced by correcting the refrigerant density in the pipe using the refrigerant temperature detection value. For this reason, more accurate refrigerant quantity determination operation is possible.
In the air conditioner according to the fifth aspect of the present invention, the temperature detecting means can be provided on the first gas refrigerant pipe without providing the temperature detecting means in the refrigerant communication pipe at the time of construction. For this reason, the effort and cost concerning construction can be reduced.

  In the air conditioner according to the sixth aspect of the present invention, the temperature detecting means can be provided on the first gas refrigerant pipe without providing the temperature detecting means in the refrigerant communication pipe at the time of construction. For this reason, the effort and cost concerning construction can be reduced. Moreover, by using together with the temperature detection means in the switching unit of the fifth invention, the refrigerant density in the pipe can be corrected with higher accuracy.

Hereinafter, embodiments of an air-conditioning apparatus according to the present invention will be described based on the drawings.
(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to an embodiment of the present invention. The 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 air conditioner 1 mainly includes an outdoor unit 2 as one heat source unit, a plurality of (in this embodiment, three) use units connected in parallel to the indoor units 3a to 3c, Connection units 4a-4c provided corresponding to the indoor units 3a-3c, a first refrigerant communication pipe group 5 for connecting the outdoor unit 2 and the connection units 4a-4c, the connection units 4a-4c, and the indoor unit 3a To 3c are connected to the second refrigerant communication pipe group 7. The first refrigerant communication pipe group 5 includes a first liquid refrigerant communication pipe 51, a high-pressure gas refrigerant communication pipe 52, and a low-pressure gas refrigerant communication pipe 53, and the second refrigerant communication pipe group 7 includes a second liquid refrigerant communication pipe. 71a to 71c and second gas refrigerant communication pipes 72a to 72c. For example, the air conditioner 1 performs a cooling operation for a certain air-conditioned space and performs a heating operation for another air-conditioned space to meet the requirements of the indoor air-conditioned space in which the indoor units 3a to 3c are installed. Accordingly, the cooling and heating simultaneous operation is possible. That is, the vapor compression refrigerant circuit 10 of the air conditioner 1 of the present embodiment includes an outdoor unit 2, indoor units 3a to 3c, connection units 4a to 4c, a first refrigerant communication pipe group 5, and a second The refrigerant communication piping group 7 is connected.

<Indoor unit>
The indoor units 3a to 3c are installed in a ceiling of a room such as a building by hanging or hanging, or on a wall surface of the room by wall hanging or the like. The indoor units 3 a to 3 c are connected to the connection units 4 a to 4 c via the second refrigerant communication pipe group 7 and constitute a part of the refrigerant circuit 10.

  Next, the configuration of the indoor units 3a to 3c will be described. Since the indoor unit 3a and the indoor units 3b and 3c have the same configuration, only the configuration of the indoor unit 3a will be described here. As for the configuration of the indoor units 3b and 3c, each part of the indoor unit 3a will be described. Xb and Xc are attached instead of Xa shown, and description of each part is omitted. For example, the indoor fan 32a of the indoor unit 3a corresponds to the indoor fans 32b and 32c of the indoor units 3b and 3c.

The indoor unit 3 a mainly has an indoor refrigerant circuit 30 a that constitutes a part of the refrigerant circuit 10. The indoor refrigerant circuit 30a mainly includes an indoor expansion valve V9a as an expansion mechanism and an indoor heat exchanger 31a as a use side heat exchanger.
The indoor expansion valve V9a is an electric expansion valve connected to the liquid side of the indoor heat exchanger 31a in order to adjust the flow rate of the refrigerant flowing in the indoor refrigerant circuit 30a.

The indoor heat exchanger 31a is a cross fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins, and functions as a refrigerant evaporator during cooling operation to cool indoor air. It is a heat exchanger that functions as a refrigerant condenser and heats indoor air during heating operation.
The indoor unit 3a has an indoor fan 32a as a blower fan that sucks indoor air into the unit and exchanges heat with a refrigerant in the indoor heat exchanger 31a and then supplies the air as indoor air. . The indoor fan 32a is a fan capable of changing the air volume Wr of air supplied to the indoor heat exchanger 31a. In the present embodiment, the indoor fan 32a is a centrifugal fan or a multiblade fan driven by a motor 33a composed of a DC fan motor. Etc.

  Various sensors are provided in the indoor unit 3a. On the liquid side of the indoor heat exchanger 31a, a liquid side temperature sensor T9a that detects the temperature of the refrigerant (that is, the refrigerant temperature corresponding to the condensation temperature Tc during the heating operation or the evaporation temperature Te during the cooling operation) is provided. Yes. A gas side temperature sensor T10a that detects the temperature Teo of the refrigerant is provided on the gas side of the indoor heat exchanger 31a. On the indoor air inlet side of the indoor unit 3a, an indoor temperature sensor T11a that detects the temperature of the indoor air flowing into the unit (that is, the indoor temperature Tr) is provided. In the present embodiment, the liquid side temperature sensor T9a, the gas side temperature sensor T10a, and the room temperature sensor T11a are composed of thermistors. Moreover, the indoor unit 3a is provided with the indoor side control part 34a which controls operation | movement of each part which comprises the indoor unit 3a. And the indoor side control part 34a has the microcomputer, memory, etc. which were provided in order to control the indoor unit 3a, and is with the remote control (not shown) for operating the indoor unit 3a separately. It is possible to exchange control signals and the like between them, and exchange control signals and the like between the outdoor unit 2 and the connection units 4a to 4c via the transmission line 8a.

<Outdoor unit>
The outdoor unit 2 is installed outside a building or the like, and is connected to the connection units 4 a to 4 c via the first refrigerant communication pipe group 5, thereby constituting the refrigerant circuit 10.
Next, the configuration of the outdoor unit 2 will be described. The outdoor unit 2 mainly has an outdoor refrigerant circuit 20 that constitutes a part of the refrigerant circuit 10. The outdoor refrigerant circuit 20 mainly includes a compressor 21, a four-way switching valve V1, an outdoor heat exchanger 22 as a heat source side heat exchanger, an outdoor expansion valve V2 as an expansion mechanism, an accumulator 23, A supercooler 24 as a temperature adjusting mechanism, a first bypass refrigerant circuit 27, a pressure reducing circuit 28, a liquid side closing valve V4, a high pressure gas side closing valve V5, a low pressure gas side closing valve V6, and a first high pressure And a gas on-off valve V8.

The compressor 21 is a compressor whose operating capacity can be varied. In the present embodiment, the compressor 21 is a positive displacement compressor driven by a motor 21a whose rotation speed Rm is controlled by an inverter. In the present embodiment, the number of the compressors 21 is only one. However, the present invention is not limited to this, and two or more compressors may be connected in parallel according to the number of indoor units connected.
The four-way switching valve V1 is a valve provided for causing the outdoor heat exchanger 22 to function as an evaporator and a condenser. The four-way switching valve V <b> 1 is connected to the refrigerant gas side of the outdoor heat exchanger 22, the suction side accumulator 23 of the compressor 21, the discharge side of the compressor 21, and the decompression circuit 28. When the outdoor heat exchanger 22 is caused to function as a condenser, the discharge side of the compressor 21 and the refrigerant gas side of the outdoor heat exchanger 22 are connected, and the accumulator 23 on the suction side of the compressor 21 is depressurized. The circuit 28 is connected. Conversely, when the outdoor heat exchanger 22 functions as an evaporator, the refrigerant gas side of the outdoor heat exchanger 22 and the suction side accumulator 23 of the compressor 21 are connected, and the discharge side of the compressor 21 The decompression circuit 28 is connected.

The outdoor heat exchanger 22 is a heat exchanger that can function as a refrigerant evaporator and a refrigerant condenser. In the present embodiment, the outdoor heat exchanger 22 is a cross fin type fin and fin that exchanges heat with the refrigerant using air as a heat source.・ Tube type heat exchanger. The outdoor heat exchanger 22 has a gas side connected to the four-way switching valve V <b> 1 and a liquid side connected to the first liquid refrigerant communication pipe 51.
The outdoor expansion valve V <b> 2 is an electric expansion valve connected to the liquid side of the outdoor heat exchanger 22 in order to adjust the pressure and flow rate of the refrigerant flowing in the outdoor refrigerant circuit 20.

  The outdoor unit 2 has an outdoor fan 25 as a blower fan for sucking outdoor air into the unit and exchanging heat with the refrigerant in the outdoor heat exchanger 22 and then discharging the air outside. The outdoor fan 25 is a fan capable of changing the air volume Wo of air supplied to the outdoor heat exchanger 22, and in this embodiment, is a propeller fan or the like driven by a motor 25a composed of a DC fan motor. .

The accumulator 23 is connected between the four-way selector valve V1 and the compressor 21, and can store surplus refrigerant generated in the refrigerant circuit 10 in accordance with fluctuations in the operating load of the indoor units 3a to 3c. It is a container. The accumulator 23 is connected to the connection units 4a to 4c via the low-pressure gas side closing valve V6 and the low-pressure gas refrigerant communication pipe 53.
In this embodiment, the supercooler 24 is a double-pipe heat exchanger, and is provided to cool the refrigerant that is condensed in the outdoor heat exchanger 22 and then sent to the indoor expansion valves V9a to V9c. ing. The subcooler 24 is connected between the outdoor expansion valve V2 and the liquid side closing valve V4.

Moreover, the 2nd bypass refrigerant circuit 6 as a cooling source of the subcooler 24 is provided. In the following description, a portion obtained by removing the second bypass refrigerant circuit 6 from the refrigerant circuit 10 will be referred to as a main refrigerant circuit for convenience.
The second bypass refrigerant circuit 6 branches a part of the refrigerant sent from the outdoor heat exchanger 22 to the indoor expansion valves V9a to V9c via the connection units 4a to 4c from the main refrigerant circuit and to the suction side of the compressor 21. It is connected to the main refrigerant circuit to return. Specifically, the second bypass refrigerant circuit 6 uses a part of the refrigerant sent from the outdoor expansion valve V2 to the indoor expansion valves V9a to V9c via the connection units 4a to 4c, and the outdoor heat exchanger 22 and the subcooler 24. And the branch circuit 61 connected to branch from the position between the second bypass refrigerant circuit 6 side of the subcooler 24 and the outlet side of the compressor 21 so as to return to the suction side of the compressor 21. And a confluence circuit 62 connected thereto. The branch circuit 61 is provided with a bypass expansion valve V7 for adjusting the flow rate of the refrigerant flowing through the second bypass refrigerant circuit 6. Here, the bypass expansion valve V7 is an electric expansion valve. Thereby, the refrigerant sent from the outdoor heat exchanger 22 to the indoor expansion valves V9a to V9c via the connection units 4a to 4c is depressurized by the bypass expansion valve V7 in the subcooler 24, and then the second bypass refrigerant circuit. It is cooled by the refrigerant flowing through 6. That is, the capacity control of the subcooler 24 is performed by adjusting the opening degree of the bypass expansion valve V7.

  The first bypass refrigerant circuit 27 is a circuit that bypasses the piping between the high-pressure gas side closing valve V5 and the discharge side of the compressor 21 and the piping between the low-pressure gas side closing valve V6 and the accumulator 23. is there. On the first bypass refrigerant circuit 27, a first bypass on-off valve V3 is provided. Here, the first bypass on-off valve V3 is an electromagnetic valve capable of circulating and blocking the refrigerant.

The decompression circuit 28 has a capillary tube C 1 and is connected to the four-way switching valve V 1 and the accumulator 23.
The liquid side closing valve V4, the high pressure gas side closing valve V5, and the low pressure gas side closing valve V6 are external devices and pipes (specifically, the first liquid refrigerant communication pipe 51, the high pressure gas refrigerant communication pipe 52, and the low pressure). It is a valve provided at the connection port with the gas refrigerant communication pipe 53). The liquid side closing valve V4 is connected to the outdoor heat exchanger 22 via the supercooler 24 and the outdoor expansion valve V2. The high pressure gas side closing valve V <b> 5 is connected to the discharge side of the compressor 21. The low-pressure gas side shut-off valve V6 is connected to the suction side of the compressor 21 via the accumulator 23.

The first high-pressure gas on-off valve V8 is provided on a pipe on the high-pressure gas side branched from the discharge side of the compressor 21, and is composed of an electromagnetic valve capable of flowing and blocking the high-pressure gas refrigerant to the high-pressure gas refrigerant communication pipe 52. .
The outdoor unit 2 is provided with various sensors. Specifically, the outdoor unit 2 includes a suction pressure sensor P1 that detects the suction pressure Ps of the compressor 21, a discharge pressure sensor P2 that detects the discharge pressure Pd of the compressor 21, and a suction temperature Ts of the compressor 21. And a discharge temperature sensor T2 for detecting the discharge temperature Td of the compressor 21 are provided. The suction temperature sensor T <b> 1 is provided at a position between the accumulator 23 and the compressor 21. The outdoor heat exchanger 22 includes a heat exchange temperature sensor that detects the temperature of the refrigerant flowing in the outdoor heat exchanger 22 (that is, the refrigerant temperature corresponding to the condensation temperature Tc during the cooling operation or the evaporation temperature Te during the heating operation). T3 is provided. On the liquid side of the outdoor heat exchanger 22, a liquid side temperature sensor T4 for detecting the refrigerant temperature Tco is provided. A liquid pipe temperature sensor T5 for detecting the temperature of the refrigerant (that is, the liquid pipe temperature Tlp) is provided at the outlet of the subcooler 24 on the main refrigerant circuit side. An outdoor temperature sensor T6 that detects the temperature of the outdoor air flowing into the unit (that is, the outdoor temperature Ta) is provided on the outdoor air inlet side of the outdoor unit 2. The junction circuit 62 of the second bypass refrigerant circuit 6 is provided with a bypass temperature sensor T7 for detecting the temperature of the refrigerant flowing through the outlet of the subcooler 24 on the second bypass refrigerant circuit 6 side. The high-pressure gas pipe between the high-pressure gas side closing valve V5 and the first high-pressure gas on / off valve V8 has a first high-pressure gas pipe temperature sensor T8 that detects the temperature of the refrigerant (that is, the first high-pressure gas pipe temperature Th1). Is provided. In the present embodiment, the suction temperature sensor T1, the discharge temperature sensor T2, the heat exchange temperature sensor T3, the liquid side temperature sensor T4, the liquid pipe temperature sensor T5, the outdoor temperature sensor T6, the bypass temperature sensor T7, and the first high pressure gas pipe temperature. The sensor T8 is a thermistor.

  The outdoor unit 2 also has an outdoor control unit 26 that controls the operation of each part constituting the outdoor unit 2. And the outdoor side control part 26 has an inverter circuit etc. which control the microcomputer provided in order to control the outdoor unit 2, a memory, and the motor 21a, etc., and the indoor side control part of indoor unit 3a-3c Control signals and the like can be exchanged via the transmission line 8a between 34a to 34c and connection side control units 44a to 44c of connection units 4a to 4c described later. That is, the control part 8 which performs operation control of the whole air conditioning apparatus 1 with the transmission line 8a which connects between the indoor side control parts 34a-34c, the connection side control parts 44a-44c, the outdoor side control part 26, and each control part. Is configured.

  As shown in FIG. 2, the control unit 8 is connected so as to receive detection signals from various sensors P1, P2, T1 to T8, T9a to T9c, T10a to T10c, T11a to T11c, and T12a to T12c. And various devices and valves 21, 25, 32a to 32c, V1 to V3, V7, V8, V9a to V9c, V10a to V10c, V11a to V11c, V12a to V12c, V13a to V13c based on these detection signals and the like. Connected so that it can be controlled. The control unit 8 is connected to a warning display unit 9 including an LED or the like for notifying that a refrigerant leak has been detected in the refrigerant leak detection operation described later. Here, FIG. 2 is a control block diagram of the air conditioner 1.

<Connection unit>
The connection units 4a to 4c are installed together with the indoor units 3a to 3c in a room such as a building. The connection units 4 a to 4 c are interposed between the indoor units 3 a to 3 c and the outdoor unit 2 together with the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7, and constitute a part of the refrigerant circuit 10. is doing.

  Next, the configuration of the connection units 4a to 4c will be described. Since the connection unit 4a and the connection units 4b and 4c have the same configuration, only the configuration of the connection unit 4a will be described here. As for the configuration of the connection units 4b and 4c, each part of the connection unit 4a will be described. The reference numerals Yb and Yc are attached instead of the reference numerals Ya, and the description of each part is omitted. For example, the supercooler 41a of the connection unit 4a corresponds to the supercoolers 41b and 41c of the connection units 4b and 4c.

The connection unit 4a constitutes a part of the refrigerant circuit 10 and includes a connection-side refrigerant circuit 40a. The connection-side refrigerant circuit 40a mainly includes a supercooler 41a, a decompression circuit 42a, a third bypass refrigerant circuit 43a, a low pressure gas on / off valve V10a, and a second high pressure gas on / off valve V11a.
The subcooler 41a sends a part of the liquid refrigerant returned to the first liquid refrigerant communication pipe 51 to the subcooler 41a through the decompression circuit 42a described later when the indoor units 3a to 3c perform the cooling and heating simultaneous operation. This is a device for supercooling the liquid refrigerant returned to the one-liquid refrigerant communication pipe 51. A part of the liquid refrigerant introduced into the supercooler 41 a evaporates by heat exchange and is returned to the outdoor refrigerant circuit 20 through the low-pressure gas refrigerant communication pipe 53. In the decompression circuit 42a, a decompression circuit on-off valve V12a and a capillary tube C2a are connected in series.

The third bypass refrigerant circuit 43 a is a circuit that bypasses the high-pressure gas refrigerant communication pipe 52 and the low-pressure gas refrigerant communication pipe 53. A second bypass on-off valve V13a is provided on the third bypass refrigerant circuit 43a. Here, the second bypass on-off valve V13a is an electromagnetic valve capable of circulating and blocking the refrigerant.
The low-pressure gas on / off valve V10a is connected to the low-pressure gas refrigerant communication pipe 53 and is an electromagnetic valve capable of circulating and blocking the refrigerant.

The second high-pressure gas on-off valve V11a is connected to the high-pressure gas refrigerant communication pipe 52 and is an electromagnetic valve capable of circulating and blocking the refrigerant.
When the indoor unit 3a performs the cooling operation, the connection unit 4a opens the low-pressure gas on-off valve V10a and closes the second high-pressure gas on-off valve V11a. As a result, the connection unit 4a sends the liquid refrigerant flowing in from the first liquid refrigerant communication pipe 51 to the indoor expansion valve V9a of the indoor refrigerant circuit 30a, the pressure is reduced by the indoor expansion valve V9a, and evaporation is performed in the indoor heat exchanger 31a. It is possible to function to return the gas refrigerant returned to the low-pressure gas refrigerant communication pipe 53.

  Further, when the indoor unit 3a performs the heating operation, the connection unit 4a closes the low pressure gas on / off valve V10a and opens the second high pressure gas on / off valve V11a. Thereby, the connection unit 4a sends the high-pressure gas refrigerant flowing from the high-pressure gas refrigerant communication pipe 52 to the gas side of the indoor heat exchanger 31a in the indoor refrigerant circuit 30a, and is condensed in the indoor heat exchanger 31a. The liquid refrigerant can function to return to the first liquid refrigerant communication pipe 51.

Further, the connection unit 4a is provided with a second high-pressure gas pipe temperature sensor T12a that detects the temperature of the refrigerant (that is, the second high-pressure gas pipe temperature Th2) on the high-pressure gas refrigerant flow path. In the present embodiment, the second high-pressure gas pipe temperature sensor T12a is a thermistor.
Furthermore, the connection unit 4a includes a connection-side control unit 44a that controls the operation of each unit constituting the connection unit 4a. The connection-side control unit 44a includes a microcomputer and a memory provided to control the connection unit 4a, and exchanges control signals and the like with the indoor-side control unit 34a of the indoor unit 3a. Can be done.

  As described above, the outdoor refrigerant circuit 20 and the indoor refrigerant circuits 30a to 30c are connected via the connection refrigerant circuits 40a to 40c, so that the refrigerant circuit 10 of the air conditioner 1 is configured. And in the air conditioning apparatus 1 of this embodiment, it becomes possible to perform what is called simultaneous cooling and heating operation, for example, indoor unit 3c performs heating operation, while indoor unit 3a, 3b performs cooling operation. Yes.

<First refrigerant communication pipe group, second refrigerant communication pipe group>
The first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7 are refrigerant pipes constructed on site when the air conditioner 1 is installed at an installation location such as a building. Those having various lengths and pipe diameters are used according to installation conditions such as a combination of an indoor unit and a connection unit. For this reason, for example, when a new air conditioner 1 is installed, in order to calculate the refrigerant charging amount, information such as the lengths and pipe diameters of the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7 is calculated. However, the information management and the calculation of the refrigerant amount are complicated. In addition, when the existing unit is used to update the indoor unit, the outdoor unit, or the connection unit, information such as the length and diameter of the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7 is lost. There are times.

  As described above, the indoor refrigerant circuits 30a to 30c, the outdoor refrigerant circuit 20, the connection refrigerant circuits 40a to 40c, the first refrigerant communication pipe group 5, and the second refrigerant communication pipe group 7 are connected. The refrigerant circuit 10 of the air conditioner 1 is configured. In other words, the refrigerant circuit 10 is composed of the second bypass refrigerant circuit 6 and a main refrigerant circuit excluding the second bypass refrigerant circuit 6. In the air conditioner 1 according to the present embodiment, the control unit 8 including the indoor side control units 34a to 34c, the connection side control units 44a to 44c, and the outdoor side control unit 26 has four paths in the outdoor unit 2. The switching valve V1 and the first high-pressure gas on-off valve V8 and the low-pressure gas on-off valve V10a and the second high-pressure gas on-off valve V11a in the connection units 4a to 4c are switched between cooling operation, heating operation, and cooling / heating simultaneous operation. In addition, the devices of the outdoor unit 2, the indoor units 3a to 3c, and the connection units 4a to 4c are controlled according to the operation load of the indoor units 3a to 3c.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 of this embodiment is demonstrated.
As an operation mode of the air conditioner 1 of the present embodiment, control of the components of the outdoor unit 2, the indoor units 3a to 3c, and the connection units 4a to 4c is normally performed according to the operation load of each indoor unit 3a to 3c. After installation of the operation mode and the components of the air conditioner 1 (specifically, not limited to after the initial installation of the device, for example, after remodeling such as adding or removing components such as indoor units, A test run mode for performing a test run performed after repair, etc., and a refrigerant leak detection operation for determining whether or not a refrigerant leaks from the refrigerant circuit 10 after the test run is finished and a normal operation is started There is a mode.

  In the normal operation mode, mainly the cooling operation for cooling all the indoor units 3a to 3c and the heating for heating all the indoor units 3a to 3c according to the cooling and heating loads of the indoor units 3a to 3c. The operation includes simultaneous cooling and heating operations in which some of the indoor units 3a to 3c perform the cooling operation while the other indoor units perform the heating operation. In addition, regarding the simultaneous cooling and heating operation, when the outdoor heat exchanger 22 of the outdoor unit 2 functions as an evaporator due to the air conditioning load of the entire indoor units 3a to 3c (evaporation operation state), the outdoor unit 2 The outdoor heat exchanger 22 can be divided into a case where the outdoor heat exchanger 22 is operated as a condenser (condensation operation state). Note that the cooling and heating simultaneous operation mentioned here is specifically an operation in which the indoor unit 3a performs the cooling operation and the remaining indoor units 3b and 3c perform the heating operation, for example.

The test operation mode mainly includes an automatic refrigerant charging operation for charging the refrigerant into the refrigerant circuit 10, a pipe volume determination operation for detecting the volumes of the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7, The initial refrigerant quantity detection operation for detecting the initial refrigerant quantity after installing the component device or after charging the refrigerant in the refrigerant circuit 10 is included.
Hereinafter, the operation | movement in each operation mode of the air conditioning apparatus 1 is demonstrated.

<Normal operation mode>
(Cooling operation)
First, the cooling operation in the normal operation mode will be described with reference to FIGS. 1 and 2.
During the cooling operation, in the outdoor refrigerant circuit 20 of the outdoor unit 2, the outdoor heat exchanger 22 functions as a condenser by switching the four-way switching valve V1 to the state shown by the solid line in FIG. ing. The outdoor expansion valve V2 is fully opened. The liquid side closing valve V4, the high pressure gas side closing valve V5, and the low pressure gas side closing valve V6 are opened, and the first high pressure gas on / off valve V8 is closed.

  In the indoor units 3a to 3c, each of the indoor expansion valves V9a to V9c has a superheat degree SHr of the refrigerant at the outlet of the indoor heat exchangers 31a to 31c (that is, the gas side of the indoor heat exchangers 31a to 31c). The opening degree is adjusted so as to be constant at the value SHrs. In this embodiment, the superheat degree SHr of the refrigerant at the outlets of the indoor heat exchangers 31a to 31c is detected by the liquid side temperature sensors T9a to T9c from the refrigerant temperature values detected by the gas side temperature sensors T10a to T10c. The suction pressure Ps of the compressor 21 detected by subtracting the temperature value (corresponding to the evaporation temperature Te) or detected by the suction pressure sensor P1 is converted into a saturation temperature value corresponding to the evaporation temperature Te, and the gas side It is detected by subtracting the saturation temperature value of the refrigerant from the refrigerant temperature value detected by the temperature sensors T10a to T10c. Although not adopted in the present embodiment, a temperature sensor that detects the temperature of the refrigerant flowing in each of the indoor heat exchangers 31a to 31c is provided, and the refrigerant temperature corresponding to the evaporation temperature Te detected by the temperature sensor. You may make it detect the superheat degree SHr of the refrigerant | coolant in the exit of each indoor heat exchanger 31a-31c by subtracting a value from the refrigerant temperature value detected by gas side temperature sensor T10a-T10c.

  The opening of the bypass expansion valve V7 is adjusted so that the superheat degree SHb of the refrigerant at the outlet of the subcooler 24 on the second bypass refrigerant circuit 6 side becomes the superheat degree target value SHbs. In the present embodiment, the superheat degree SHb of the refrigerant at the outlet of the subcooler 24 on the second bypass refrigerant circuit 6 side is a saturation corresponding to the evaporation temperature Te by the suction pressure Ps of the compressor 21 detected by the suction pressure sensor P1. This is detected by converting to a temperature value and subtracting the saturation temperature value of the refrigerant from the refrigerant temperature value detected by the bypass temperature sensor T7. Although not adopted in this embodiment, a temperature sensor is provided at the inlet of the second bypass refrigerant circuit 6 side of the subcooler 24, and the refrigerant temperature value detected by this temperature sensor is detected by the bypass temperature sensor T7. By subtracting from the refrigerant temperature value, the superheat degree SHb of the refrigerant at the outlet of the subcooler 24 on the second bypass refrigerant circuit 6 side may be detected.

  In the connection units 4a to 4c, the second high pressure gas on / off valves V11a to V11c are closed and the low pressure gas on / off valves V10a to V10c are opened. Thereby, the indoor heat exchangers 31a to 31c of the indoor units 3a to 3c function as an evaporator, and the indoor heat exchangers 31a to 31c of the indoor units 3a to 3c and the suction side of the compressor 21 of the outdoor unit 2 are connected. The low pressure gas refrigerant communication pipe 53 is connected. Further, the pressure reducing circuit on / off valves V12a to V12c are in a closed state.

  When the compressor 21, the outdoor fan 25, and the indoor fans 32a to 32c are started in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant. Thereafter, the high-pressure gas refrigerant is sent to the outdoor heat exchanger 22 via the four-way switching valve V1, and is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 25. Become. Then, this high-pressure liquid refrigerant passes through the outdoor expansion valve V2, flows into the supercooler 24, and is further cooled by exchanging heat with the refrigerant flowing through the second bypass refrigerant circuit 6 to be in a supercooled state. . At this time, a part of the high-pressure liquid refrigerant condensed in the outdoor heat exchanger 22 is branched to the second bypass refrigerant circuit 6, and after being decompressed by the bypass expansion valve V 7, is returned to the suction side of the compressor 21. . Here, a part of the refrigerant passing through the bypass expansion valve V7 evaporates by being depressurized to near the suction pressure Ps of the compressor 21. And the refrigerant | coolant which flows toward the suction | inhalation side of the compressor 21 from the exit of the bypass expansion valve V7 of the 2nd bypass refrigerant circuit 6 passes the subcooler 24, and is indoors from the outdoor heat exchanger 22 by the side of a main refrigerant circuit. Heat exchange is performed with the high-pressure liquid refrigerant sent to the units 3a to 3c.

  Then, the high-pressure liquid refrigerant in a supercooled state is sent to the indoor units 3a to 3c via the liquid-side closing valve V4, the first liquid refrigerant communication pipe 51, and the connection units 4a to 4c. The high-pressure liquid refrigerant sent to the indoor units 3a to 3c is depressurized to the vicinity of the suction pressure Ps of the compressor 21 by the indoor expansion valves V9a to V9c, and becomes a low-pressure gas-liquid two-phase refrigerant to exchange the indoor heat. The heat is exchanged with room air in the indoor heat exchangers 31a to 31c and evaporated to become a low-pressure gas refrigerant.

  The low-pressure gas refrigerant is sent to the low-pressure gas refrigerant communication pipe 53 through the low-pressure gas on / off valves V10a to V10c of the connection units 4a to 4c. The low-pressure gas refrigerant is sent to the outdoor unit 2 via the low-pressure gas refrigerant communication pipe 53 and flows into the accumulator 23 through the low-pressure gas side closing valve V6. The low-pressure gas refrigerant that has flowed into the accumulator 23 is again sucked into the compressor 21.

(Heating operation)
During the heating operation, in the outdoor refrigerant circuit 20 of the outdoor unit 2, the four-way switching valve V1 is switched to the state shown by the broken line in FIG. 1, so that the outdoor heat exchanger 22 functions as an evaporator and the high pressure The high-pressure gas refrigerant compressed and discharged in the compressor 21 is supplied to the indoor units 3a to 3c through the gas refrigerant communication pipe 52. The degree of opening of the outdoor expansion valve V2 is adjusted in order to reduce the refrigerant flowing into the outdoor heat exchanger 22 to a pressure at which the refrigerant can be evaporated in the outdoor heat exchanger 22 (that is, the evaporation pressure Pe). Yes. Further, the liquid side closing valve V4, the high pressure gas side closing valve V5, and the low pressure gas side closing valve V6 are opened, and the bypass expansion valve V7 and the first high pressure gas on / off valve V8 are opened.

  In the indoor units 3a to 3c, the indoor expansion valves V9a to V9c are such that the degree of supercooling of the refrigerant SCr at the outlets of the indoor heat exchangers 31a to 31c (that is, the liquid side of the indoor heat exchangers 31a to 31c) is the degree of supercooling. The opening degree is adjusted so as to be constant at the target value SCrs. In the present embodiment, the degree of refrigerant supercooling SCr at the outlets of the indoor heat exchangers 31a to 31c is converted into a saturation temperature value corresponding to the condensation temperature Tc from the discharge pressure Pd of the compressor 21 detected by the discharge pressure sensor P2. Then, it is detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensors T9a to T9c from the saturation temperature value of the refrigerant. In addition, although not employ | adopted in this embodiment, the temperature sensor which detects the temperature of the refrigerant | coolant which flows through each indoor heat exchanger 31a-31c is provided, and the refrigerant | coolant temperature corresponding to the condensation temperature Tc detected by this temperature sensor The subcooling degree SCr of the refrigerant at the outlets of the indoor heat exchangers 31a to 31c may be detected by subtracting the value from the refrigerant temperature value detected by the liquid side temperature sensors T9a to T9c.

In the connection units 4a to 4c, the low pressure gas on / off valves V10a to V10c are closed and the second high pressure gas on / off valves V11a to V11c are opened, whereby the indoor heat exchangers 31a to 31c of the indoor units 3a to 3c are used as condensers. Become functional. Further, the pressure reducing circuit on / off valves V12a to V12c are in an open state.
When the compressor 21, the outdoor fan 25, and the indoor fans 32a to 32c are started in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant. It is sent to the high pressure gas refrigerant communication pipe 52 via the valve V1 and the high pressure gas side closing valve V5.

  The high-pressure gas refrigerant sent to the high-pressure gas refrigerant communication pipe 52 is sent to the connection units 4a to 4c. The high-pressure gas refrigerant sent to the connection units 4a to 4c is sent to the indoor units 3a to 3c through the second high-pressure gas on / off valves V11a to V11c. The high-pressure gas refrigerant sent to the indoor units 3a to 3c is subjected to heat exchange with indoor air in the indoor heat exchangers 31a to 31c to be condensed into high-pressure liquid refrigerant, and then the indoor expansion valves V9a to V9a to When passing through V9c, the pressure is reduced according to the opening degree of the indoor expansion valves V9a to V9c.

  And the refrigerant | coolant which passed indoor expansion valve V9a-V9c is sent to the subcoolers 41a-41c of connection unit 4a-4c. The supercooled refrigerant liquid is sent to the outdoor unit 2 via the first liquid refrigerant communication pipe 51 and further decompressed via the liquid side closing valve V4 and the outdoor expansion valve V2, and then the outdoor heat exchange. Flows into the vessel 22. Then, the low-pressure gas-liquid two-phase refrigerant flowing into the outdoor heat exchanger 22 exchanges heat with the outdoor air supplied by the outdoor fan 25 to evaporate into a low-pressure gas refrigerant, and the four-way switching valve V1. Flows into the accumulator 23. Then, the low-pressure gas refrigerant that has flowed into the accumulator 23 is again sucked into the compressor 21.

(Simultaneous cooling / heating operation / evaporation load)
Among the indoor units 3a to 3c, for example, a cooling / heating simultaneous operation in which the indoor unit 3a is cooled and the indoor units 3b and 3c are heated, depending on the air conditioning load of the entire indoor units 3a to 3c. An operation (evaporation operation) for causing the outdoor heat exchanger 22 of the unit 2 to function as an evaporator will be described. At this time, as in the above-described heating operation mode, the four-way switching valve V1 is switched to the state shown by the broken line in FIG. 1, whereby the outdoor heat exchanger 22 functions as an evaporator and the high-pressure gas refrigerant communication pipe. The high-pressure gas refrigerant compressed and discharged by the compressor 21 is supplied to the two indoor units 3b and 3c that perform the heating operation through 52. At this time, the bypass expansion valve V7 is closed, and the first high-pressure gas on-off valve V8 is opened.

In the indoor unit 3a, the indoor expansion valve V9a is, for example, the degree of superheat of the indoor heat exchanger 31a (specifically, the refrigerant temperature detected by the liquid side temperature sensor T9a and the refrigerant detected by the gas side temperature sensor T10a). The degree of opening is adjusted according to the cooling load of the indoor unit 3a, such as the degree of opening is adjusted based on the temperature difference from the temperature.
In the connection unit 4a, the second high pressure gas on / off valve V11a is closed and the low pressure gas on / off valve V10a is opened. Thus, the indoor heat exchanger 31a of the indoor unit 3a functions as an evaporator, and the indoor heat exchanger 31a of the indoor unit 3a and the suction side of the compressor 21 of the outdoor unit 2 are connected via the low-pressure gas refrigerant communication pipe 53. Connected. Further, the pressure reducing circuit on / off valve V12a is in a closed state.

In the indoor units 3b and 3c, the indoor expansion valves V9b and V9c have excessive refrigerant supercooling degrees SCr at the outlets of the indoor heat exchangers 31b and 31c (that is, the liquid side of the indoor heat exchangers 31b and 31c). The opening degree is adjusted so as to be constant at the cooling target value SCrs.
In the connection units 4b and 4c, the low pressure gas on / off valves V10b and V10c are closed and the second high pressure gas on / off valves V11b and V11c are opened. Thereby, the indoor heat exchangers 31b and 31c of the indoor units 3b and 3c are in a state of functioning as a condenser. Further, the pressure reducing circuit on / off valves V12b and V12c are in an open state.

In this state of the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to the high-pressure gas refrigerant communication pipe 52 through the high-pressure gas side closing valve V5.
Then, the high-pressure gas refrigerant sent to the high-pressure gas refrigerant communication pipe 52 is sent to the indoor units 3b and 3c through the connection units 4b and 4c and the second high-pressure gas on / off valves V11b and V11c. The high-pressure gas refrigerant sent to the indoor units 3b and 3c exchanges heat with indoor air in the indoor heat exchangers 31b and 31c to be condensed into high-pressure liquid refrigerant, and then the indoor expansion valves V9b and V9c. Is passed, the pressure is reduced according to the opening degree of the indoor expansion valves V9b, V9c. On the other hand, room air is heated and supplied indoors.

  The refrigerant that has passed through the indoor expansion valves V9b and V9c is sent to the subcoolers 41b and 41c of the connection units 4b and 4c to be supercooled. The supercooled refrigerant liquid is sent to the first liquid refrigerant communication pipe 51, and a part of the liquid refrigerant sent to the first liquid refrigerant communication pipe 51 is sent to the connection unit 4a. And the refrigerant | coolant sent to the connection unit 4a is sent to the indoor expansion valve V9a of the indoor unit 3a.

The refrigerant sent to the indoor expansion valve V9a is depressurized by the indoor expansion valve V9a and then evaporated by exchanging heat with the indoor air in the indoor heat exchanger 31a to become a low-pressure gas refrigerant. On the other hand, room air is cooled and supplied indoors. Then, the low-pressure gas refrigerant is sent to the connection unit 4a.
The low-pressure gas refrigerant sent to the connection unit 4a is sent to the outdoor unit 2 through the low-pressure gas on / off valve V10a and the low-pressure gas refrigerant communication pipe 53, and flows into the accumulator 23 via the low-pressure gas side closing valve V6. Then, the low-pressure gas refrigerant that has flowed into the accumulator 23 is again sucked into the compressor 21.

On the other hand, the remaining refrigerant excluding the refrigerant sent from the first liquid refrigerant communication pipe 51 to the connection unit 4a and the indoor unit 3a is sent to the outdoor heat exchanger 22 through the liquid side closing valve V4 of the outdoor unit 2, It is evaporated in the heat exchanger 22 to become a low-pressure gas refrigerant. This gas refrigerant is sucked into the compressor 21 via the four-way switching valve V1 and the accumulator 23.
(Simultaneous cooling / heating operation / condensation load)
Among the indoor units 3a to 3c, for example, in the cooling / heating simultaneous operation mode in which the indoor units 3a and 3b are cooled and the indoor unit 3c is heated, depending on the air conditioning load of the entire indoor units 3a to 3c, An operation (condensation operation) for causing the outdoor heat exchanger 22 of the outdoor unit 2 to function as a condenser will be described. At this time, the four-way switching valve V1 is switched to the state shown by the solid line in FIG. 1 so that the outdoor heat exchanger 22 functions as a condenser and the compressor 21 is connected to the indoor unit 3c through the high-pressure gas refrigerant communication pipe 52. The high-pressure gas refrigerant compressed and discharged in is supplied. At this time, the first high-pressure gas on-off valve V8 is open.

  In the indoor units 3a and 3b, the indoor expansion valves V9a and V9b are, for example, the degree of superheat of the indoor heat exchangers 31a and 31b (specifically, the refrigerant temperature and gas side detected by the liquid side temperature sensors T9a and T9b). The opening degree is adjusted according to the cooling load of each indoor unit 3a, 3b, for example, the opening degree is adjusted based on the temperature difference between the refrigerant temperature detected by the temperature sensors T10a, T10b).

  In the connection units 4a and 4b, the second high pressure gas on / off valves V11a and V11b are closed and the low pressure gas on / off valves V10a and V10b are opened. Thereby, the indoor heat exchangers 31a and 31b of the indoor units 3a and 3b function as an evaporator, and the indoor heat exchangers 31a and 31b of the indoor units 3a and 3b and the suction side of the compressor 21 of the outdoor unit 2 are connected. The low pressure gas refrigerant communication pipe 53 is connected. Further, the pressure reducing circuit on / off valves V12a and V12b are in a closed state.

In the indoor unit 3c, the indoor expansion valve V9c is detected, for example, by the degree of supercooling of the indoor heat exchanger 31c (specifically, the refrigerant temperature detected by the liquid side temperature sensor T9c and the gas side temperature sensor T10c). The opening degree is adjusted in accordance with the heating load of the indoor unit 3c, such as the opening degree is adjusted based on the temperature difference from the refrigerant temperature.
In the connection unit 4c, the low pressure gas on / off valve V10c is closed and the second high pressure gas on / off valve V11c is opened. Thereby, the indoor heat exchanger 31c of the indoor unit 3c enters a state of functioning as a condenser. Further, the pressure reducing circuit on / off valve V12c is in an open state.

In such a state of the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is sent to the outdoor heat exchanger 22 through the four-way switching valve V1, and the high-pressure gas through the high-pressure gas side closing valve V5. It is also sent to the refrigerant communication pipe 52.
The high-pressure gas refrigerant sent to the outdoor heat exchanger 22 is condensed in the outdoor heat exchanger 22 and becomes a liquid refrigerant. Then, the liquid refrigerant is sent to the first liquid refrigerant communication pipe 51 through the liquid side closing valve V4.

Further, the high-pressure gas refrigerant sent to the high-pressure gas refrigerant communication pipe 52 is sent to the connection unit 4c. The high-pressure gas refrigerant sent to the connection unit 4c is sent to the indoor heat exchanger 31c of the indoor unit 3c through the second high-pressure gas on / off valve V11c.
The high-pressure gas refrigerant sent to the indoor heat exchanger 31c is condensed by exchanging heat with indoor air in the indoor heat exchanger 31c of the indoor unit 3c. On the other hand, indoor air is heated and supplied indoors. The refrigerant condensed in the indoor heat exchanger 31c passes through the indoor expansion valve V9c and is then sent to the connection unit 4c.

The refrigerant sent to the connection unit 4c is sent to the first liquid refrigerant communication pipe 51 and merged with the refrigerant sent to the first liquid refrigerant communication pipe 51 through the liquid-side closing valve V4. The refrigerant flowing through the first liquid refrigerant communication pipe 51 is sent to the indoor expansion valves V9a and V9b of the indoor units 3a and 3b via the connection units 4a and 4b.
The refrigerant sent to the indoor expansion valves V9a and V9b is depressurized by the indoor expansion valves V9a and V9b, and then evaporated by exchanging heat with the indoor air in the indoor heat exchangers 31a and 31b. It becomes. On the other hand, room air is cooled and supplied indoors. Then, the low-pressure gas refrigerant is sent to the connection units 4a and 4b.

The low-pressure gas refrigerant sent to the connection units 4a and 4b is sent to the low-pressure gas refrigerant communication pipe 53 through the low-pressure gas on-off valves V10a and V10b. The low-pressure gas refrigerant sent to the low-pressure gas refrigerant communication pipe 53 is sucked into the compressor 21 via the low-pressure gas side closing valve V6 and the accumulator 23.
The operation control in the normal operation mode as described above is performed by the control unit 8 (more specifically, the indoor side control units 34a to 34c, the connection side) functioning as normal operation control means for performing normal operation including cooling operation and heating operation. This is performed by the control units 44a to 44c, the outdoor side control unit 26, and the transmission lines 8a) connecting the control units 34a to 34c, 44a to 44c, 26.

<Trial run mode>
Next, the trial operation mode will be described with reference to FIGS. Here, FIG. 3 is a flowchart of the test operation mode. In the present embodiment, in the test operation mode, first, the refrigerant automatic charging operation in step S1 is performed, then the pipe volume determination operation in step S2 is performed, and further, the initial refrigerant amount detection operation in step S3 is performed.

  In the present embodiment, the outdoor unit 2 pre-filled with the refrigerant, the indoor units 3a to 3c, and the connection units 4a to 4c are installed at an installation location such as a building, and the first refrigerant communication pipe group 5 and the second refrigerant are installed. After connecting through the communication pipe group 7 and configuring the refrigerant circuit 10, the refrigerant that is insufficient depending on the volume of the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7 is added to the refrigerant circuit 10. The case of filling will be described as an example.

(Step S1: Refrigerant automatic charging operation)
First, the liquid side closing valve V4, the high pressure gas side closing valve V5, and the low pressure gas side closing valve V6 of the outdoor unit 2 are opened to fill the refrigerant circuit 10 with the refrigerant filled in the outdoor unit 2 in advance.
Next, an operator who performs a test operation connects a refrigerant cylinder for additional charging to a service port (not shown) of the refrigerant circuit 10 and remotely to the control unit 8 directly or through a remote controller (not shown). When a command to start a trial run is issued from step S4, the control unit 8 performs steps S11 to S13 shown in FIG. Here, FIG. 4 is a flowchart of the automatic refrigerant charging operation.

(Step S11: refrigerant quantity determination operation)
When an instruction to start the automatic refrigerant charging operation is made, the refrigerant circuit 10 is in a state where the four-way switching valve V1 of the outdoor unit 2 is indicated by a solid line in FIG. 1 and the indoor expansion valves V9a to V9a of the indoor units 3a to 3c V9c, the low pressure gas on / off valves V10a to V10c of the connection units 4a to 4c, and the outdoor expansion valve V2 are opened, and the first high pressure gas on / off valve V8 of the outdoor unit 2 and the second high pressure gas on / off valves of the connection units 4a to 4c. V11a to V11c are closed, the compressor 21, the outdoor fan 25, and the indoor fans 32a to 32c are activated to forcibly cool all the indoor units 3a to 3c (hereinafter referred to as all indoor unit operations). Is done. At this time, the first bypass on-off valve V3 on the first bypass refrigerant circuit 27 in the outdoor unit 2, and the second bypass on-off valves V13a to V13c on the third bypass refrigerant circuits 43a to 43c in the connection units 4a to 4c, Is opened, and the refrigerant pressure in the high-pressure gas refrigerant communication pipe 52 and the low-pressure gas refrigerant communication pipe 53 is equalized.

  Then, as shown in FIG. 5, in the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged in the compressor 21 is flown from the compressor 21 to the outdoor heat exchanger 22 that functions as a condenser. 5 (refer to the portion from the compressor 21 to the outdoor heat exchanger 22 in the hatched portion in FIG. 5), the outdoor heat exchanger 22 functioning as a condenser is liquidated from the gas state by heat exchange with outdoor air. The high-pressure refrigerant that changes in phase flows (see the portion corresponding to the outdoor heat exchanger 22 in the hatched and black hatched portions in FIG. 5), and the indoor expansion valves V9a to V9a to The flow path to V9c (including the outdoor expansion valve V2, the main refrigerant circuit side portion of the subcooler 24 and the first liquid refrigerant communication pipe 51) and the flow path from the outdoor heat exchanger 22 to the bypass expansion valve V7 Is Pressure refrigerant flows (refer to the portions from the outdoor heat exchanger 22 to the indoor expansion valves V9a to V9c and the bypass expansion valve V7 in the black hatched portion in FIG. 5), and the indoor heat exchanger that functions as an evaporator Low-pressure refrigerant that changes phase from a gas-liquid two-phase state to a gas state flows through the portions 31a to 31c and the portion of the subcooler 24 on the second bypass refrigerant circuit 6 side through heat exchange with room air or the like (see FIG. 5) (refer to the indoor heat exchangers 31 a to 31 c and the subcooler 24) among the grid-like hatching and hatched hatching portions of FIG. 5, and the flow paths from the indoor heat exchangers 31 a to 31 c to the compressor 21. In the high pressure gas side and low pressure gas side flow paths (including the third bypass refrigerant circuits 43a to 43c), the high pressure gas refrigerant communication pipe 52, the low pressure gas refrigerant communication pipe 53, the first of the connection units 4a to 4c. Low-pressure gas refrigerant flows through the flow path including the bypass refrigerant circuit 27 and the accumulator 23 and the flow path from the portion on the second bypass refrigerant circuit 6 side of the supercooler 24 to the compressor 21 (FIG. 5). Among the hatched portions of the line, portions from the indoor heat exchangers 31a to 31c to the compressor 21 (including the connection units 4a to 4c, the high-pressure gas refrigerant communication pipe 52, and the low-pressure gas refrigerant communication pipe 53) and a supercooler 24) (refer to the part from the second bypass refrigerant circuit 6 side to the compressor 21). FIG. 5 is a schematic diagram showing the state of the refrigerant flowing in the refrigerant circuit 10 in the refrigerant quantity determination operation (illustration of the four-way switching valve V1 and the like is omitted).

  Next, the following device control is performed to shift to an operation for stabilizing the state of the refrigerant circulating in the refrigerant circuit 10. Specifically, the indoor expansion valves V9a to V9c are controlled (hereinafter referred to as superheat control) so that the superheat degree SHr of the indoor heat exchangers 31a to 31c functioning as evaporators is constant, and the evaporation pressure Pe is The operation capacity of the compressor 21 is controlled so as to be constant (hereinafter referred to as evaporation pressure control), and the outdoor heat exchanger 25 uses the outdoor heat exchanger so that the refrigerant condensing pressure Pc in the outdoor heat exchanger 22 becomes constant. The supercooler 24 controls the air volume Wo of the outdoor air supplied to 22 (hereinafter referred to as condensing pressure control) so that the temperature of the refrigerant sent from the supercooler 24 to the indoor expansion valves V9a to V9c becomes constant. The indoor heat exchangers 31a-3 are controlled by the indoor fans 32a-32c so that the refrigerant evaporating pressure Pe is stably controlled by the above evaporating pressure control. The air volume Wr of room air supplied to the c is a constant.

  Here, the evaporation pressure control is performed in the indoor heat exchangers 31a to 31c functioning as an evaporator, while the low-pressure refrigerant is changed in phase from a gas-liquid two-phase state to a gas state by heat exchange with indoor air. Refrigerant in the flowing indoor heat exchangers 31a to 31c (refer to the portion corresponding to the indoor heat exchangers 31a to 31c in the lattice-shaped hatched and hatched portions in FIG. 5 and hereinafter referred to as the evaporator section C). This is because the amount greatly affects the evaporation pressure Pe of the refrigerant. And here, by controlling the operating capacity of the compressor 21 by the motor 21a whose rotational speed Rm is controlled by the inverter, the refrigerant evaporating pressure Pe in the indoor heat exchangers 31a to 31c is made constant, and the evaporator section The state of the refrigerant flowing in C is stabilized. That is, a state in which the amount of refrigerant in the evaporator C is mainly changed by the evaporation pressure Pe is created. In the control of the evaporation pressure Pe by the compressor 21 of the present embodiment, the refrigerant temperature values (corresponding to the evaporation temperature Te) detected by the liquid side temperature sensors T9a to T9c of the indoor heat exchangers 31a to 31c are used as the saturation pressure. The operating capacity of the compressor 21 is controlled so that this pressure value becomes constant at the low pressure target value Pes (that is, control for changing the rotational speed Rm of the motor 21a) is performed so that the refrigerant becomes a refrigerant. This is realized by increasing or decreasing the refrigerant circulation amount Wc flowing in the circuit 10. Although not employed in the present embodiment, the compressor 21 detected by the suction pressure sensor P1, which is an operation state quantity equivalent to the refrigerant pressure at the refrigerant evaporation pressure Pe in the indoor heat exchangers 31a to 31c, is used. The compressor 21 is set so that the suction pressure Ps becomes constant at the low pressure target value Pes, or the saturation temperature value (corresponding to the evaporation temperature Te) corresponding to the suction pressure Ps becomes constant at the low pressure target value Tes. May be controlled, and the refrigerant temperature value (corresponding to the evaporation temperature Te) detected by the liquid side temperature sensors T9a to T9c of the indoor heat exchangers 31a to 31c becomes constant at the low pressure target value Tes. As such, the operating capacity of the compressor 21 may be controlled.

  And by performing such evaporation pressure control, in the refrigerant | coolant piping containing the low pressure gas refrigerant | coolant communication piping 53 and the accumulator 23 from the indoor heat exchangers 31a-31c to the compressor 21 (in the hatched part of the hatching of FIG. 5) Among them, the state of the refrigerant flowing through the indoor heat exchangers 31a to 31c to the compressor 21 (hereinafter referred to as the gas refrigerant circulation part D) is also stable, mainly to the refrigerant pressure in the gas refrigerant circulation part D. A state in which the refrigerant amount in the gas refrigerant circulation portion D is changed by the evaporation pressure Pe (that is, the suction pressure Ps), which is an equivalent operation state quantity, is created.

  Condensation pressure control is performed in the outdoor heat exchanger 22 in which a high-pressure refrigerant flows through a phase change from a gas state to a liquid state by heat exchange with outdoor air (hatched hatching and black hatching in FIG. 5). This is because the amount of refrigerant in the portion corresponding to the outdoor heat exchanger 22 (hereinafter referred to as the condenser part A) greatly affects the refrigerant condensing pressure Pc. And since the condensing pressure Pc of the refrigerant | coolant in this condenser part A changes largely from the influence of outdoor temperature Ta, it controls the air volume Wo of the indoor air supplied to the outdoor heat exchanger 22 from the outdoor fan 25 with the motor 25a. Thus, the refrigerant condensing pressure Pc in the outdoor heat exchanger 22 is kept constant, and the state of the refrigerant flowing in the condenser part A is stabilized. That is, the state in which the amount of refrigerant in the condenser A changes mainly due to the degree of supercooling SCo on the liquid side of the outdoor heat exchanger 22 (hereinafter referred to as the outlet of the outdoor heat exchanger 22 in the description of the refrigerant amount determination operation). Is producing. In the control of the condensation pressure Pc by the outdoor fan 25 of the present embodiment, the compressor 21 detected by the discharge pressure sensor P2, which is an operating state quantity equivalent to the refrigerant condensation pressure Pc in the outdoor heat exchanger 22, is used. The discharge pressure Pd or the temperature of the refrigerant flowing through the outdoor heat exchanger 22 detected by the heat exchange temperature sensor T3 (that is, the condensation temperature Tc) is used.

  And by performing such condensing pressure control, the flow path from the outdoor heat exchanger 22 to the indoor expansion valves V9a to V9c (the outdoor expansion valve V2 and the part on the main refrigerant circuit side of the subcooler 24 and the first liquid High-pressure liquid refrigerant flows through the flow path from the outdoor heat exchanger 22 to the bypass expansion valve V7 of the second bypass refrigerant circuit 6, and the indoor heat expansion from the outdoor heat exchanger 22 to the indoor expansion. The pressure of the refrigerant in the portions up to the valves V9a to V9c and the bypass expansion valve V7 (see the black hatched portion in FIG. 5, hereinafter referred to as the liquid refrigerant circulation portion B) is also stable, and the liquid refrigerant circulation portion B becomes the liquid refrigerant. It is sealed with a stable state.

  Further, the liquid pipe temperature control is performed in the refrigerant pipe including the first liquid refrigerant communication pipe 51 extending from the supercooler 24 to the indoor expansion valves V9a to V9c (in the liquid refrigerant circulation part B shown in FIG. This is to prevent the refrigerant density from changing from the cooler 24 to the indoor expansion valves V9a to V9c). In the capacity control of the subcooler 24, the refrigerant temperature Tlp detected by the liquid tube temperature sensor T5 provided at the outlet of the subcooler 24 on the main refrigerant circuit side becomes constant at the liquid tube temperature target value Tlps. As described above, the flow rate of the refrigerant flowing through the second bypass refrigerant circuit 6 is increased or decreased to adjust the amount of exchange heat between the refrigerant flowing through the main refrigerant circuit side of the subcooler 24 and the refrigerant flowing through the second bypass refrigerant circuit 6 side. Has been realized. In addition, increase / decrease in the flow volume of the refrigerant | coolant which flows through this 2nd bypass refrigerant circuit 6 is performed by opening degree adjustment of the bypass expansion valve V7. In this way, liquid pipe temperature control is realized in which the refrigerant temperature in the refrigerant pipe including the first liquid refrigerant communication pipe 51 extending from the supercooler 24 to the indoor expansion valves V9a to V9c is constant.

  Then, the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 22 (that is, the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger 22) exerted by the increase in the amount of refrigerant due to the refrigerant circuit 10 being filled with the refrigerant. Even if there is a change, by performing such a constant liquid pipe temperature control, the effect of the change in the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 22 is supercooled from the outlet of the outdoor heat exchanger 22. It fits only in the refrigerant piping leading to the vessel 24. For this reason, the change in the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 22 is caused by the refrigerant piping from the subcooler 24 to the indoor expansion valves V9a to V9c including the first liquid refrigerant communication piping 51 in the liquid refrigerant circulation portion B. It will be in a state that does not affect.

  Furthermore, the superheat degree control is performed because the amount of refrigerant in the evaporator section C greatly affects the dryness of the refrigerant at the outlets of the indoor heat exchangers 31a to 31c. The degree of superheat SHr of the refrigerant at the outlets of the indoor heat exchangers 31a to 31c is controlled on the gas side of the indoor heat exchangers 31a to 31c (hereinafter referred to as refrigerant amount determination operation) by controlling the opening degree of the indoor expansion valves V9a to V9c. In the description, the refrigerant superheat degree SHr in the indoor heat exchangers 31a to 31c is made constant at the superheat degree target value SHrs (that is, the gas refrigerant at the outlets of the indoor heat exchangers 31a to 31c is used). The state of the refrigerant flowing in the evaporator section C is stabilized by making it overheated.

And the state which a gas refrigerant | coolant flows reliably to the gas refrigerant | coolant distribution part D is created by performing such superheat degree control.
By the various controls described above, the state of the refrigerant circulating in the refrigerant circuit 10 is stabilized, and the distribution of the refrigerant amount in the refrigerant circuit 10 becomes constant. When the refrigerant starts to be charged, it is possible to create a state in which the change in the refrigerant amount in the refrigerant circuit 10 appears mainly as a change in the refrigerant amount in the outdoor heat exchanger 22 (hereinafter, this operation is referred to as refrigerant). (It is assumed to be volume judgment operation).

The control as described above is performed by the control unit 8 (more specifically, the indoor side control units 34a to 34c, the connection side control units 44a to 44c, the outdoor side, which functions as a refrigerant amount determination operation control unit that performs the refrigerant amount determination operation. The control unit 26 and the transmission lines 8a) connecting the control units 34a to 34c, 44a to 44c, and 26 perform the process of step S11.
Note that, unlike the present embodiment, when the outdoor unit 2 is not prefilled with refrigerant, the constituent devices are abnormally stopped prior to the processing in step S11 when the refrigerant amount determination operation is performed. It is necessary to charge the refrigerant until the amount of the refrigerant is low.

(Step S12: Calculation of refrigerant amount)
Next, while performing the refrigerant amount determination operation, the refrigerant circuit 10 is additionally charged with the refrigerant. At this time, the control unit 8 functioning as the refrigerant amount calculating means performs additional refrigerant charging in step S12. The refrigerant amount in the refrigerant circuit 10 is calculated from the refrigerant flowing through the refrigerant circuit 10 or the operating state quantity of the component equipment.

  First, the refrigerant quantity calculating means in this embodiment will be described. The refrigerant quantity calculating means calculates the refrigerant quantity in the refrigerant circuit 10 by dividing the refrigerant circuit 10 into a plurality of parts and calculating the refrigerant quantity for each of the divided parts. More specifically, for each divided part, a relational expression between the refrigerant amount of each part and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is set, and these relational expressions are used. The amount of refrigerant in each part can be calculated. In the present embodiment, the refrigerant circuit 10 is in a state where the four-way switching valve V1 is indicated by a solid line in FIG. 1, that is, the discharge side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 22, and In the state where the suction side of the compressor 21 is connected to the outlets of the indoor heat exchangers 31a to 31c via the low-pressure gas side closing valve V6 and the low-pressure gas refrigerant communication pipe 53, the compressor 21 part and the compressor 21 are four-way A portion up to the outdoor heat exchanger 22 (hereinafter referred to as a high pressure gas pipe portion E) including the switching valve V1 (not shown in FIG. 5), a portion of the outdoor heat exchanger 22 (that is, the condenser portion A), In the liquid refrigerant circulation part B, the part from the outdoor heat exchanger 22 to the supercooler 24 and the inlet side half of the part on the main refrigerant circuit side of the supercooler 24 (hereinafter referred to as the high temperature side liquid pipe part B1); Of the subcooler 24 in the liquid refrigerant circulation part B The outlet side half of the medium circuit side part and the part from the supercooler 24 to the liquid side shut-off valve V4 (not shown in FIG. 5) (hereinafter referred to as the low temperature side liquid pipe part B2), the liquid refrigerant circulation part B Part of the first liquid refrigerant communication pipe 51, the liquid side refrigerant flow paths of the connection units 4a to 4c and the second liquid refrigerant communication pipes 71a to 71c (hereinafter referred to as liquid refrigerant communication pipe part B3), Of the liquid refrigerant circulation part B, the second of the gas refrigerant circulation parts D including the first liquid refrigerant communication pipe 51 and the indoor expansion valves V9a to V9c and the indoor heat exchangers 31a to 31c (ie, the evaporator part C). A portion from the gas refrigerant communication pipes 72a to 72c (hereinafter referred to as an indoor unit part F) and a high pressure gas side refrigerant flow path in the high pressure gas refrigerant communication pipe 52 and the connection units 4a to 4c in the gas refrigerant circulation part D ( Third bypass refrigerant circuits 43a to 43c A portion including the second bypass on-off valves V13a to V13c on the high-pressure gas side (hereinafter referred to as the high-pressure gas refrigerant communication pipe portion G1), and the low-pressure gas refrigerant communication pipe 53 in the gas refrigerant circulation portion D; The second gas refrigerant communication pipes 72a to 72c and the low pressure gas side refrigerant flow paths in the connection units 4a to 4c (including the second bypass on-off valves V13a to V13c on the low pressure gas side of the third bypass refrigerant circuits 43a to 43c); Between the high pressure gas side closing valve V5 (not shown in FIG. 5) and the first high pressure gas on / off valve V8 in the gas refrigerant circulation portion D (hereinafter referred to as the low pressure gas refrigerant communication pipe portion G2). A portion (hereinafter referred to as a first low pressure gas pipe portion H), a low pressure gas side closing valve V6 (not shown in FIG. 5) to the first bypass refrigerant circuit 27, the first bypass refrigerant circuit 27, and the first bypass refrigerant. Circuit 27 To the four-way switching valve V1 and the first bypass refrigerant circuit 27 to the compressor 21 including the accumulator 23 (hereinafter referred to as the second low-pressure gas pipe part I), and the liquid refrigerant circulation part B A portion from the high temperature side liquid pipe portion B1 to the second low pressure gas pipe portion I including a portion of the bypass expansion valve V7 and the subcooler 24 on the second bypass refrigerant circuit 6 side (hereinafter referred to as a second bypass circuit portion J). The relational expression is set for each part. In addition, let the part which combined the high pressure gas refrigerant communication piping part G1 and the low pressure gas refrigerant communication piping part G2 be the gas refrigerant communication piping part G. Next, the relational expressions set for each part will be described.

In the present embodiment, the relational expression between the refrigerant amount Mog1 in the high-pressure gas pipe part E and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mog1 = Vog1 × ρd
This is expressed as a functional expression obtained by multiplying the volume Vog1 of the high-pressure gas pipe E of the outdoor unit 2 by the refrigerant density ρd in the high-pressure gas pipe E. The volume Vog1 of the high-pressure gas pipe E is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. Moreover, the density ρd of the refrigerant in the high-pressure gas pipe E can be obtained by converting the discharge temperature Td and the discharge pressure Pd.

The relational expression between the refrigerant amount Mc in the condenser part A and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mc = kc1 * Ta + kc2 * Tc + kc3 * SHm + kc4 * Wc
+ Kc5 × ρc + kc6 × ρco + kc7
A function of the outdoor temperature Ta, the condensation temperature Tc, the compressor discharge superheat degree SHm, the refrigerant circulation amount Wc, the saturated liquid density ρc of the refrigerant in the outdoor heat exchanger 22, and the refrigerant density ρco at the outlet of the outdoor heat exchanger 22 Expressed as an expression. Note that the parameters kc1 to kc7 in the above relational expression are obtained by regression analysis of the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. The compressor discharge superheat degree SHm is the superheat degree of the refrigerant on the discharge side of the compressor, and the discharge pressure Pd is converted into the saturation temperature value of the refrigerant, and the saturation temperature value of the refrigerant is subtracted from the discharge temperature Td. can get. The refrigerant circulation amount Wc is expressed as a function of the evaporation temperature Te and the condensation temperature Tc (that is, Wc = f (Te, Tc)). The saturated liquid density ρc of the refrigerant is obtained by converting the condensation temperature Tc. The refrigerant density ρco at the outlet of the outdoor heat exchanger 22 is obtained by converting the condensation pressure Pc obtained by converting the condensation temperature Tc and the refrigerant temperature Tco.

The relational expression between the refrigerant amount Mol1 in the high temperature side liquid pipe part B1 and the operation state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mol1 = Vol1 × ρco
As a functional expression obtained by multiplying the volume Vol1 of the high temperature side liquid pipe portion B1 of the outdoor unit 2 by the refrigerant density ρco in the high temperature side liquid pipe portion B1 (that is, the refrigerant density at the outlet of the outdoor heat exchanger 22 described above). expressed. Note that the volume Vol1 of the high temperature side liquid pipe portion B1 is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant amount Mol2 in the low temperature side liquid pipe part B2 and the operation state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mol2 = Vol2 × ρlp
This is expressed as a functional expression obtained by multiplying the volume Vol2 of the low temperature side liquid pipe portion B2 of the outdoor unit 2 by the refrigerant density ρlp in the low temperature side liquid pipe portion B2. The volume Vol2 of the low temperature side liquid pipe part B2 is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. Further, the refrigerant density ρlp in the low temperature side liquid pipe portion B2 is the refrigerant density at the outlet of the supercooler 24, and is obtained by converting the condensation pressure Pc and the refrigerant temperature Tlp at the outlet of the supercooler 24. .

The relational expression between the refrigerant amount Mlp in the liquid refrigerant communication pipe part B3 and the operation state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mlp = Vlp × ρlp
The density of the refrigerant in the liquid refrigerant communication pipe portion B3 is the volume Vlp of the portion that combines the first liquid refrigerant communication pipe 51, the liquid side refrigerant flow paths of the connection units 4a to 4c, and the second liquid refrigerant communication pipes 71a to 71c. It is expressed as a function equation multiplied by ρlp (that is, the density of the refrigerant at the outlet of the subcooler 24). Here, Vlp is divided into the volume Vlp1 of the portion where the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c are combined, and the volume Vlp2 of the liquid side refrigerant flow path of the connection units 4a to 4c. Is done. The volume Vlp1 of the portion where the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c are combined is such that the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c are the air conditioner 1. This is a refrigerant pipe that is installed on the site when installing it at the installation location such as a building, so you can enter values calculated locally from information such as length and pipe diameter, and information such as length and pipe diameter And the controller 8 calculates from the input information of the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c, or the pipe volume determination operation is performed as described later. It is calculated using the operation result. Further, the volume Vlp2 of the liquid side refrigerant flow path of the connection units 4a to 4c is a known value before the connection units 4a to 4c are installed at the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant amount Mr in the indoor unit part F and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mr = kr1 × Tlp + kr2 × ΔT + kr3 × SHr + kr4 × Wr + kr5
The refrigerant temperature Tlp at the outlet of the supercooler 24, the temperature difference ΔT obtained by subtracting the evaporation temperature Te from the indoor temperature Tr, the superheat degree SHr of the refrigerant at the outlets of the indoor heat exchangers 31a to 31c, and the indoor fans 32a to 32c. It is expressed as a function expression of the air volume Wr. Note that the parameters kr1 to kr5 in the above relational expression are obtained by regression analysis of the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. Here, the relational expression of the refrigerant amount Mr is set corresponding to each of the three indoor units 3a to 3c, and the refrigerant amount Mr of the indoor unit 3a, the refrigerant amount Mr of the indoor unit 3b, and the indoor unit 3c. The total refrigerant amount of the indoor unit F is calculated by adding the refrigerant amount Mr. When the models and capacities of the indoor unit 3a, the indoor unit 3b, and the indoor unit 3c are different, relational expressions having different values of the parameters kr1 to kr5 are used.

  The gas refrigerant communication pipe part G is divided into a high pressure gas refrigerant communication pipe part G1 and a low pressure gas refrigerant communication pipe part G2, and the refrigerant amount Mgp of the gas refrigerant communication pipe part G is the refrigerant amount of the high pressure gas refrigerant communication pipe part G1. This is a value obtained by adding Mgph and the refrigerant amount Mgpl of the low-pressure gas refrigerant communication pipe part G2. Further, the volume Vgp of the gas refrigerant communication pipe part G is a value obtained by adding the volume Vgph of the high pressure gas refrigerant communication pipe part G1 and the volume Vgpl of the low pressure gas refrigerant communication pipe part G2. That is, these relational expressions are as follows.

Mgp = Mgph + Mgpl
Vgp = Vgph + Vgpl
The relational expression between the refrigerant amount Mgph in the high-pressure gas refrigerant communication pipe part G1 and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mgph = Vgph × ρgph
The high-pressure gas refrigerant communication pipe 52 and the high-pressure gas-side refrigerant passages in the connection units 4a to 4c (including the second bypass on-off valves V13a to V13c on the high-pressure gas side of the third bypass refrigerant circuits 43a to 43c). It is expressed as a function formula obtained by multiplying the combined volume Vgph by the refrigerant density ρgph in the high-pressure gas refrigerant communication pipe part G1. Here, Vgph is the volume Vgph1 of the high-pressure gas refrigerant communication pipe 52 and the high-pressure gas-side refrigerant flow path in the connection units 4a to 4c (the second bypass on-off valve V13a on the high-pressure gas side of the third bypass refrigerant circuits 43a to 43c). To V13c) (including up to V13c). The volume Vgp1 of the high-pressure gas refrigerant communication pipe 52 is the same as that of the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c. Because it is a refrigerant pipe that is installed on site when installing at a location such as, etc., enter values calculated locally from information such as length and pipe diameter, or enter information such as length and pipe diameter locally And it calculates by the control part 8 from the information of these input high-pressure-gas-refrigerant connection piping 52, or it calculates using the operation result of piping volume determination driving | operation as mentioned later. In addition, the refrigerant density ρgph in the high-pressure gas refrigerant communication pipe section G1 includes the refrigerant density ρs on the suction side of the compressor 21, the high-pressure gas side closing valve V5 and the first high-pressure gas on-off valve V8 in the outdoor unit 2. The refrigerant density ρoh in the high-pressure gas side pipe between them, the refrigerant density ρbsh in the high-pressure gas-side refrigerant flow path in the connection units 4a to 4c, and the outlets of the indoor heat exchangers 31a to 31c (that is, the second gas refrigerant) It is an average value with the density ρeo of the refrigerant in the inlet pipes 72a to 72c). The density ρs of the refrigerant is obtained by converting the suction pressure Ps and the suction temperature Ts. The density ρoh of the refrigerant is obtained by converting the first high-pressure gas pipe temperature Th1. The density ρbsh of the refrigerant is obtained by converting the second high-pressure gas pipe temperature Th2. The refrigerant density ρeo is obtained by converting the evaporation pressure Pe, which is a conversion value of the evaporation temperature Te, and the outlet temperatures Teo of the indoor heat exchangers 31a to 31c. Further, the volume Vgp2 of the high pressure gas side refrigerant flow path (including the second bypass open / close valves V13a to V13c on the high pressure gas side of the third bypass refrigerant circuits 43a to 43c) in the connection units 4a to 4c is determined by the connection units 4a to 4c. 4c is a known value before being installed at the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant quantity Mgpl in the low-pressure gas refrigerant communication pipe part G2 and the operation state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mgpl = Vgpl × ρgpl
The low pressure gas refrigerant communication pipe 53, the second gas refrigerant communication pipes 72a to 72c, and the low pressure gas side refrigerant flow path in the connection units 4a to 4c (the second bypass opening and closing on the low pressure gas side of the third bypass refrigerant circuits 43a to 43c). The volume Vgpl of the portion including the valves V13a to V13c) is multiplied by the refrigerant density ρgpl in the low-pressure gas refrigerant communication pipe part G2. Here, Vgpl is the volume Vgpl1 of the portion where the low-pressure gas refrigerant communication pipe 53 and the second gas refrigerant communication pipes 72a to 72c are combined, and the low-pressure gas-side refrigerant flow path (third bypass refrigerant in the connection units 4a to 4c). And the second bypass on-off valves V13a to V13c on the low-pressure gas side of the circuits 43a to 43c). The volume Vgpl1 of the part combining the low-pressure gas refrigerant communication pipe 53 and the second gas refrigerant communication pipes 72a to 72c is the part including the first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipes 71a to 71c and the high pressure. Similarly to the gas refrigerant communication pipe 52, the low pressure gas refrigerant communication pipe 53 and the second gas refrigerant communication pipes 72a to 72c are refrigerant pipes that are installed on site when the air conditioner 1 is installed at an installation location such as a building. Therefore, a value calculated locally from information such as length and pipe diameter is input, or information such as length and pipe diameter is input locally, and the low-pressure gas refrigerant communication pipe 53 and the second gas that have been input are input. It calculates by the control part 8 from the information with refrigerant | coolant communication piping 72a-72c, or uses the operation result of piping volume determination driving | operation as mentioned later. The refrigerant density ρgpl in the low-pressure gas refrigerant communication pipe part G2 is equal to the refrigerant density ρs on the suction side of the compressor 21 and the outlets of the indoor heat exchangers 31a to 31c (that is, the second gas refrigerant communication pipes 72a to 72c). And the refrigerant density ρeo at the inlet). The refrigerant density ρs is obtained by converting the suction pressure Ps and the suction temperature Ts. The refrigerant density ρeo is the conversion value of the evaporation temperature Te and the outlet temperature Teo of the indoor heat exchangers 31a to 31c. Is obtained by converting. Further, the volume Vgpl2 of the low pressure gas side refrigerant flow path (including the second bypass open / close valves V13a to V13c on the low pressure gas side of the third bypass refrigerant circuits 43a to 43c) in the connection units 4a to 4c is determined by the connection units 4a to 4c. 4c is a known value before being installed at the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant amount Mog2 in the first low-pressure gas pipe part H and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mog2 = Vog2 × ρoh
This is expressed as a functional expression obtained by multiplying the volume Vog2 of the first low-pressure gas pipe H in the outdoor unit 2 by the refrigerant density ρoh in the first low-pressure gas pipe H. Note that the volume Vog2 of the first low-pressure gas pipe H is a known value before being shipped to the installation location, and is stored in the memory of the controller 8 in advance.

The relational expression between the refrigerant amount Mog3 in the second low-pressure gas pipe part I and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mog3 = Vog3 × ρs
This is expressed as a functional expression obtained by multiplying the volume Vog3 of the second low-pressure gas pipe section I in the outdoor unit 2 by the refrigerant density ρs in the second low-pressure gas pipe section I. The volume Vog3 of the second low-pressure gas pipe part I is a known value before being shipped to the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant amount Mob in the second bypass circuit section J and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mob = kob1 × ρco + kob2 × ρs + kob3 × Pe + kob4
The refrigerant density ρco at the outlet of the outdoor heat exchanger 22, the refrigerant density ρs at the outlet of the subcooler 24 on the bypass circuit side, and the evaporation pressure Pe are expressed as functional expressions. The parameters kob1 to kob3 in the above relational expression are obtained by performing regression analysis on the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. Further, the volume Mob of the second bypass circuit portion J may have a smaller refrigerant amount than other portions, and may be calculated by a simpler relational expression. For example,
Mob = Vob × ρe × kob5
This is expressed as a functional expression obtained by multiplying the volume Vob of the second bypass circuit portion J by the saturated liquid density ρe and the correction coefficient kob in the portion of the subcooler 24 on the second bypass circuit side. Note that the volume Vob of the second bypass circuit unit J is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. Further, the saturated liquid density ρe in the portion on the second bypass circuit side of the subcooler 24 is obtained by converting the suction pressure Ps or the evaporation temperature Te.

  In the present embodiment, the number of outdoor units 2 is one, but when a plurality of outdoor units are connected, the refrigerant amounts Mog1, Mc, Mol1, Mol2, Mog2, Mog3, and Mob related to the outdoor units are: A relational expression of the refrigerant amount of each part is set corresponding to each of the plurality of outdoor units, and the total refrigerant quantity of the outdoor unit is calculated by adding the refrigerant amount of each part of the plurality of outdoor units. It has become. In addition, when a plurality of outdoor units having different models and capacities are connected, a relational expression of the refrigerant amount of each part having different parameter values is used.

As described above, in the present embodiment, the refrigerant quantity of each part is calculated from the refrigerant flowing through the refrigerant circuit 10 or the operation state quantity of the component device in the refrigerant quantity judgment operation using the relational expression for each part of the refrigerant circuit 10. Thus, the refrigerant amount of the refrigerant circuit 10 can be calculated.
And since this step S12 is repeated until the conditions of determination of the appropriateness | suitableness of the refrigerant | coolant amount in below-mentioned step S13 are satisfy | filled, it is about each part of the refrigerant circuit 10 until it completes after the additional charge of a refrigerant | coolant is started. Using the relational expression, the amount of refrigerant in each part is calculated from the operating state amount when the refrigerant is charged. More specifically, the refrigerant amount Mo in the outdoor unit 2, the refrigerant amount Mr in each of the indoor units 3a to 3c, and the connection units 4a to 4c that are necessary for determining whether the refrigerant amount is appropriate in step S13 described later. The refrigerant amount Mbs (= Vlp2 × ρlp + Vgp2 × ρgp) (that is, the refrigerant amount of each part of the refrigerant circuit 10 excluding the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7) is calculated. Here, the refrigerant amount Mo in the outdoor unit 2 is calculated by adding the refrigerant amounts Mog1, Mc, Mol1, Mol2, Mog2, Mog3, and Mob of each part in the outdoor unit 2 described above.

In this way, the control unit 8 that functions as the refrigerant amount calculating means for calculating the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 or the operation state quantity of the component device in the refrigerant automatic charging operation, the step S12. Is performed.
(Step S13: Determination of appropriateness of refrigerant amount)
As described above, when additional charging of the refrigerant into the refrigerant circuit 10 is started, the refrigerant amount in the refrigerant circuit 10 gradually increases. Here, when the volume of the first refrigerant communication pipe group 5 is unknown, the refrigerant amount to be charged in the refrigerant circuit 10 after the additional charging of the refrigerant may be defined as the refrigerant amount of the entire refrigerant circuit 10. Can not. However, if attention is paid only to the outdoor unit 2, the indoor units 3a to 3c, and the connection units 4a to 4c (that is, the refrigerant circuit 10 excluding the first refrigerant communication pipe group 5 and the second refrigerant communication pipe group 7), Since the optimum refrigerant amount of the outdoor unit 2 in the normal operation mode can be known in advance by detailed simulation, this refrigerant amount is stored in advance in the memory of the control unit 8 as the filling target value Ms, and the above relational expression is obtained. The refrigerant amount Mo of the outdoor unit 2, the refrigerant amount Mr of the indoor units 3a to 3c, and the refrigerant of the connection units 4a to 4c calculated from the refrigerant flowing in the refrigerant circuit 10 in the automatic refrigerant charging operation or the operation state quantity of the component device. It is sufficient to perform additional charging of the refrigerant until the value of the refrigerant amount obtained by adding the amount Mbs reaches the charging target value Ms. That is, in step S13, the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2, the refrigerant amount Mr of the indoor units 3a to 3c, and the refrigerant amount Mbs of the connection units 4a to 4c in the automatic refrigerant charging operation is the charging target value. This is a process for determining whether or not the amount of refrigerant charged in the refrigerant circuit 10 by additional charging of refrigerant is appropriate by determining whether or not Ms has been reached.

  In step S13, the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2, the refrigerant amount Mr of the indoor units 3a to 3c, and the refrigerant amount Mbs of the connection units 4a to 4c is smaller than the charging target value Ms. If the additional charging of the refrigerant has not been completed, the process of step S13 is repeated until the charging target value Ms is reached. Further, when the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2, the refrigerant amount Mr of the indoor units 3a to 3c, and the refrigerant amount Mbs of the connection units 4a to 4c reaches the charging target value Ms, Is completed, and step S1 as the automatic refrigerant charging operation processing is completed.

  In the refrigerant amount determination operation described above, as the additional charging of the refrigerant into the refrigerant circuit 10 proceeds, the degree of supercooling SCo at the outlet of the outdoor heat exchanger 22 tends to increase mainly, and the outdoor heat exchanger. The refrigerant amount Mc in 22 increases, and the refrigerant amount in other parts tends to be kept substantially constant. For this reason, the charging target value Ms is set as a value corresponding to only the refrigerant amount Mo of the outdoor unit 2, not the outdoor unit 2, the indoor units 3a to 3c, and the connection units 4a to 4c, or the outdoor heat exchange. It may be set as a value corresponding to the refrigerant amount Mc of the vessel 22 and additional refrigerant charging may be performed until the charging target value Ms is reached.

As described above, the control unit 8 that functions as a refrigerant amount determination unit that determines the suitability of the refrigerant amount in the refrigerant circuit 10 in the refrigerant amount determination operation of the automatic refrigerant charging operation (that is, whether or not the charging target value Ms has been reached). Step S13 is performed.
(Step S2: Pipe volume judgment operation)
When the automatic refrigerant charging operation in step S1 is completed, the process proceeds to a pipe volume determination operation in step S2. In the pipe volume determination operation, the processing of step S21 to step S25 shown in FIG. Here, FIG. 6 is a flowchart of the pipe volume determination operation.

(Steps S21 and S22: Pipe volume determination operation for liquid refrigerant communication pipe and calculation of volume)
In step S21, liquid refrigerant communication piping including indoor unit total number operation, condensation pressure control, liquid pipe temperature control, superheat degree control, and evaporation pressure control is performed in the same manner as the refrigerant amount determination operation in step S11 in the automatic refrigerant charging operation described above. The pipe volume determination operation for the part B3 is performed. Here, the liquid pipe temperature target value Tlps of the refrigerant temperature Tlp at the outlet on the main refrigerant circuit side of the subcooler 24 in the liquid pipe temperature control is set as the first target value Tlps1, and the refrigerant amount determination operation is performed based on the first target value Tlps1. Is the first state (see the refrigeration cycle indicated by the line including the broken line in FIG. 7). FIG. 7 is a Mollier diagram showing the refrigeration cycle of the air-conditioning apparatus 1 in the pipe volume determination operation for the liquid refrigerant communication pipe.

  Next, from the first state in which the refrigerant temperature Tlp at the outlet on the main refrigerant circuit side of the subcooler 24 in the liquid pipe temperature control is stabilized at the first target value Tlps1, other equipment control, that is, condensing pressure control, overheating, is performed. Without changing the conditions of the degree control and the evaporation pressure control (that is, without changing the superheat degree target value SHrs and the low pressure target value Tes), the liquid pipe temperature target value Tlps is different from the first target value Tlps1. The second state is changed to the target value Tlps2 and stabilized (see the refrigeration cycle shown by the solid line in FIG. 7). In the present embodiment, the second target value Tlps2 is a temperature higher than the first target value Tlps1.

  Thus, since the density of the refrigerant | coolant in liquid refrigerant communication piping part B3 becomes small by changing from the stable state in a 1st state to a 2nd state, the refrigerant | coolant amount of liquid refrigerant communication piping part B3 in a 2nd state Mlp decreases as compared to the refrigerant amount in the first state. And the refrigerant | coolant decreased from this liquid refrigerant communication piping part B3 will move to the other part of the refrigerant circuit 10. FIG. More specifically, as described above, since the conditions for equipment control other than the liquid pipe temperature control are not changed, the refrigerant amount Mog1 in the high pressure gas pipe E and the first low pressure gas pipe H The refrigerant amount Mog2, the refrigerant amount Mog3 in the second low-pressure gas pipe part I, the refrigerant quantity Mgph in the high-pressure gas refrigerant communication pipe part G1, and the refrigerant quantity Mgpl in the low-pressure gas refrigerant communication pipe part G2 are kept substantially constant, so that the liquid refrigerant The refrigerant decreased from the communication pipe part B3 moves to the condenser part A, the high temperature side liquid pipe part B1, the low temperature side liquid pipe part B2, the indoor unit part F, and the second bypass circuit part J. That is, the refrigerant amount Mc in the condenser part A, the refrigerant quantity Mol1 in the high temperature side liquid pipe part B1, the refrigerant quantity Mol2 in the low temperature side liquid pipe part B2, and the indoor unit part by the amount of refrigerant reduced from the liquid refrigerant communication pipe part B3 The refrigerant amount Mr in F and the refrigerant amount Mob in the second bypass circuit portion J increase.

  The control as described above is performed by the control unit 8 (more specifically, the indoor side control unit that functions as a pipe volume determination operation control unit that performs a pipe volume determination operation for calculating the volume Mlp of the liquid refrigerant communication pipe unit B3. 34a to 34c, the connection side control units 44a to 44c, the outdoor side control unit 26, and the transmission line 8a) connecting the control units 34a to 34c, 44a to 44c, 26, are performed as the process of step S21.

Next, in step S22, the change from the first state to the second state makes use of the phenomenon that the refrigerant decreases from the liquid refrigerant communication pipe part B3 and moves to the other part of the refrigerant circuit 10 to make liquid refrigerant communication. The volume Vlp of the piping part B3 is calculated.
First, an arithmetic expression used to calculate the volume Vlp of the liquid refrigerant communication pipe portion B3 will be described. The amount of refrigerant that has decreased from the liquid refrigerant communication piping section B3 and moved to the other part of the refrigerant circuit 10 by the above-described pipe volume determination operation is defined as the refrigerant increase / decrease amount ΔMlp, and the refrigerant in each part between the first and second states. ΔMc, ΔMol1, ΔMol2, ΔMr, and ΔMob (here, the refrigerant amount Mog1, the refrigerant amount Mog2, the refrigerant amount Mog3, the refrigerant amount Mgph, and the refrigerant amount Mgpl are omitted because they are kept substantially constant). Then, the refrigerant increase / decrease amount ΔMlp is, for example,
ΔMlp = − (ΔMc + ΔMol1 + ΔMol2 + ΔMr + ΔMob)
It can be calculated from the function expression Then, by dividing the value of ΔMlp by the refrigerant density change Δρlp between the first and second states in the liquid refrigerant communication pipe section B3, the volume Vlp of the liquid refrigerant communication pipe section B3 can be calculated. . Note that, although the calculation result of the refrigerant increase / decrease amount ΔMlp is hardly affected, the refrigerant quantity Mog1 and the refrigerant quantity Mog2 may be included in the above-described function formula.

Vlp = ΔMlp / Δρlp
Further, since the volume Vlp2 of the liquid side refrigerant flow path of the connection units 4a to 4c is a known value before the connection units 4a to 4c are installed at the installation location, the liquid refrigerant communication pipe part B3 obtained by calculation is used. The first liquid refrigerant communication pipe 51 and the second liquid refrigerant communication pipe 71a, which are refrigerant pipes constructed on site when the air conditioner 1 is installed at a place such as a building, are subtracted from the volume Vlp of The volume Vlp1 of the portion combined with 71c can be obtained.

  Note that ΔMc, ΔMol1, ΔMol2, ΔMr, and ΔMob calculate the refrigerant amount in the first state and the refrigerant amount in the second state by using the relational expressions for the respective parts of the refrigerant circuit 10 described above, and It is obtained by subtracting the refrigerant amount in the first state from the refrigerant amount in the two states. The density change amount Δρlp is calculated from the refrigerant density at the outlet of the subcooler 24 in the first state and the refrigerant density at the outlet of the subcooler 24 in the second state, and further from the refrigerant density in the second state. It is obtained by subtracting the density of the refrigerant in the first state.

Using the above arithmetic expression, the volume Vlp of the liquid refrigerant communication pipe section B3 can be calculated from the refrigerant flowing through the refrigerant circuit 10 in the first and second states or the operation state quantity of the component equipment.
In the present embodiment, the state is changed so that the second target value Tlps2 in the second state is higher than the first target value Tlps1 in the first state, and the refrigerant in the low temperature side liquid pipe part B2 is changed to another temperature. The refrigerant amount in the other part is increased by moving to the part, and the volume Vlp of the liquid refrigerant communication pipe part B3 is calculated from this increased amount. The second target value Tlps2 in the second state is the first state. The state is changed so that the temperature is lower than the first target value Tlps1 in FIG. 1, and the refrigerant amount in the other part is decreased by moving the refrigerant from the other part to the liquid refrigerant communication pipe part B3. May calculate the volume Vlp of the liquid refrigerant communication pipe section B3.

As described above, the liquid refrigerant communication pipe for calculating the volume Vlp of the liquid refrigerant communication pipe section B3 from the refrigerant flowing in the refrigerant circuit 10 in the pipe volume determination operation for the liquid refrigerant communication pipe section B3 or the operation state quantity of the component equipment. The process of step S22 is performed by the control unit 8 functioning as a pipe volume calculating means.
(Steps S23 and S24: Pipe volume determination operation for gas refrigerant communication pipe and calculation of volume)
After the above-described steps S21 and S22 are completed, in step S23, the piping volume for the gas refrigerant communication piping section G including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat control, and the evaporation pressure control. Perform judgment operation. Here, the low pressure target value Pes of the suction pressure Ps of the compressor 21 in the evaporation pressure control is set as the first target value Pes1, and the state in which the refrigerant amount determination operation is stabilized at the first target value Pes1 is set as the first state (FIG. (Refer to the refrigeration cycle indicated by a line containing 8 dashed lines). FIG. 8 is a Mollier diagram showing the refrigeration cycle of the air-conditioning apparatus 1 in the pipe volume determination operation for the gas refrigerant communication pipe.

  Next, from the first state where the low pressure target value Pes of the suction pressure Ps of the compressor 21 in the evaporation pressure control is stabilized at the first target value Pes1, other device control, that is, liquid pipe temperature control, condensation pressure control, and The second target value Pes2 is different from the first target value Pes1 without changing the superheat degree control condition (that is, without changing the liquid pipe temperature target value Tlps and the superheat degree target value SHrs). To a stable second state (refer to the refrigeration cycle shown only by the solid line in FIG. 8). In the present embodiment, the second target value Pes2 is a pressure lower than the first target value Pes1.

  Thus, since the density of the refrigerant | coolant in gas refrigerant communication piping part G becomes small by changing from the stable state in the 1st state to the 2nd state, the refrigerant quantity of gas refrigerant communication piping part G in the 2nd state Mgp decreases compared to the refrigerant amount in the first state. And the refrigerant | coolant decreased from this gas refrigerant communication piping part G will move to the other part of the refrigerant circuit 10. FIG. More specifically, as described above, since the device control conditions other than the evaporation pressure control are not changed, the refrigerant amount Mog1 in the high-pressure gas pipe part E and the refrigerant quantity in the high temperature side liquid pipe part B1 Mol 1, the refrigerant amount Mol 2 in the low temperature side liquid pipe part B 2, and the refrigerant quantity Mlp in the liquid refrigerant communication pipe part B 3 are kept substantially constant, and the refrigerant reduced from the gas refrigerant communication pipe part G is the first low-pressure gas pipe part H, the second low-pressure gas pipe part I, the condenser part A, the indoor unit part F, and the second bypass circuit part J will be moved. That is, the refrigerant amount Mog2 in the first low-pressure gas pipe part H, the refrigerant quantity Mog3 in the second low-pressure gas pipe part I, the refrigerant quantity Mc in the condenser part A, the amount of the refrigerant reduced from the gas refrigerant communication pipe part G, The refrigerant quantity Mr in the unit part F and the refrigerant quantity Mob in the second bypass circuit part J will increase.

  The above control is performed by the control unit 8 (more specifically, the indoor side control unit that functions as a pipe volume determination operation control unit that performs a pipe volume determination operation for calculating the volume Vgp of the gas refrigerant communication pipe unit G. 34a to 34c, the connection side control units 44a to 44c, the outdoor side control unit 26, and the transmission line 8a) connecting the control units 34a to 34c, 44a to 44c, 26, are performed as the process of step S23.

Next, in step S24, the change from the first state to the second state makes use of the phenomenon that the refrigerant decreases from the gas refrigerant communication pipe part G and moves to the other part of the refrigerant circuit 10 to make the gas refrigerant communication. The volume Vgp of the piping part G is calculated.
First, an arithmetic expression used for calculating the volume Vgp of the gas refrigerant communication pipe section G will be described. Refrigerant increase / decrease amount ΔMgp is defined as the refrigerant amount that has decreased from the gas refrigerant communication pipe part G and moved to the other part of the refrigerant circuit 10 by the pipe volume determination operation described above, and the refrigerant in each part between the first and second states. Assuming that the amount of increase / decrease is ΔMc, ΔMog2, ΔMog3, ΔMr, and ΔMob (here, the refrigerant amount Mog1, the refrigerant amount Mol1, the refrigerant amount Mol2, and the refrigerant amount Mlp are omitted because they are kept substantially constant) The quantity ΔMgp is, for example,
ΔMgp = − (ΔMc + ΔMog2 + ΔMog3 + ΔMr + ΔMob)
It can be calculated from the function expression Then, by dividing the value of ΔMgp by the refrigerant density change Δρgp between the first and second states in the gas refrigerant communication pipe part G, the volume Vgp of the gas refrigerant communication pipe part G can be calculated. . Note that, although the calculation result of the refrigerant increase / decrease amount ΔMgp is hardly affected, the refrigerant quantity Mog1, the refrigerant quantity Mol1, and the refrigerant quantity Mol2 may be included in the above-described functional formula.

Vgp = ΔMgp / Δρgp
ΔMc, ΔMog2, ΔMog3, ΔMr, and ΔMob calculate the refrigerant amount in the first state and the refrigerant amount in the second state by using the relational expressions for the respective parts of the refrigerant circuit 10 described above. The density change amount Δρgp is obtained by subtracting the refrigerant amount in the first state from the refrigerant amount in the two states, and the density change amount Δρgp is equal to the refrigerant density ρs on the suction side of the compressor 21 in the first state, The refrigerant density ρoh in the high-pressure gas-side piping between the high-pressure gas side shut-off valve V5 and the first high-pressure gas on-off valve V8, the refrigerant density ρbsh in the high-pressure gas side refrigerant flow path in the connection units 4a to 4c, To calculate the average density with the refrigerant density ρeo at the outlets of the indoor heat exchangers 31a to 31c and subtract the average density in the first state from the average density in the second state. Therefore, it is obtained.

The volume Vgp of the gas refrigerant communication pipe section G can be calculated from the refrigerant flowing through the refrigerant circuit 10 in the first and second states or the operation state quantity of the component equipment using the above arithmetic expression.
Further, the volume Vgp2 of the high pressure gas side refrigerant flow path and the low pressure gas side refrigerant flow path (including the third bypass refrigerant circuit 43a to 43c part) in the connection units 4a to 4c is set at the installation location of the connection units 4a to 4c. Since it is a known value before being installed, it is subtracted from the volume Vgp of the gas refrigerant communication pipe part G obtained by calculation, so that the air conditioner 1 is installed on the site when it is installed at a place such as a building. The volume Vgp1 of the portion combining the high-pressure gas refrigerant communication pipe 52, the low-pressure gas refrigerant communication pipe 53, and the second gas refrigerant communication pipes 72a to 72c, which are refrigerant pipes, can be obtained.

  In the present embodiment, the state is changed so that the second target value Pes2 in the second state is lower than the first target value Pes1 in the first state, and the refrigerant in the gas refrigerant communication pipe section G is changed to another The amount of refrigerant in the other part is increased by moving to the part, and the volume Vlp of the gas refrigerant communication pipe part G is calculated from this increased amount. However, the second target value Pes2 in the second state is the first state. The state is changed so that the pressure is higher than the first target value Pes1 in the above, and the refrigerant amount in the other part is decreased by moving the refrigerant from the other part to the gas refrigerant communication pipe part G. From the above, the volume Vlp of the gas refrigerant communication pipe part G may be calculated.

Thus, the gas refrigerant communication pipe for calculating the volume Vgp of the gas refrigerant communication pipe part G from the refrigerant flowing in the refrigerant circuit 10 in the pipe volume determination operation for the gas refrigerant communication pipe part G or the operation state quantity of the component equipment. The process of step S24 is performed by the control unit 8 functioning as a pipe volume calculating means.
(Step S25: Determination of the validity of the result of the pipe volume determination operation)
After the above-described steps S21 to S24 are completed, in step S25, whether or not the result of the pipe volume determination operation is appropriate, that is, the volume Vlp of the liquid refrigerant communication pipe part B3 calculated by the pipe volume calculating means. And the volume Vgp of the gas refrigerant communication pipe part G are determined as appropriate.

Specifically, as in the following inequality, determination is made based on whether the ratio of the volume Vlp of the liquid refrigerant communication pipe part B3 to the volume Vgp of the gas refrigerant communication pipe part G obtained by the calculation is within a predetermined numerical range. To do.
ε1 <Vlp / Vgp <ε2
Here, ε1 and ε2 are values that are varied based on the minimum value and the maximum value of the pipe volume ratio in a feasible combination of the heat source unit and the utilization unit.

When the volume ratio Vlp / Vgp satisfies the above numerical range, the processing of step S2 for the pipe volume determination operation is completed. When the volume ratio Vlp / Vgp does not satisfy the above numerical range, The pipe volume determination operation and the volume calculation process in steps S21 to S24 are performed.
Thus, whether or not the result of the pipe volume determination operation described above is appropriate, that is, the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G calculated by the pipe volume calculation means. The process of step S25 is performed by the control unit 8 that functions as a validity determination unit that determines whether or not is appropriate.

In the present embodiment, the pipe volume determination operation for the liquid refrigerant communication pipe section B3 (steps S21 and S22) is performed first, and then the pipe volume determination operation for the gas refrigerant communication pipe section G (step S23, S22). Although S24) is performed, the pipe volume determination operation for the gas refrigerant communication pipe section G may be performed first.
Further, in the above-described step S25, when it is determined a plurality of times that the result of the pipe volume determination operation in steps S21 to S24 is not appropriate, or more simply, the volume Vlp of the liquid refrigerant communication pipe part B3 and the gas refrigerant When it is desired to make a determination with the volume Vgp of the communication pipe part G, although not shown in FIG. 6, for example, in step S25, it is determined that the result of the pipe volume determination operation in steps S21 to S24 is not valid. Later, the pipe length of the refrigerant communication pipe part K is estimated from the pressure loss in the portion (hereinafter referred to as the refrigerant communication pipe part K) that combines the liquid refrigerant communication pipe part B3 and the gas refrigerant communication pipe part G. Shifting to a process of calculating the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G from the pipe length and the average volume ratio, the volume of the liquid refrigerant communication pipe part B3 It may be obtained and the volume Vgp of lp and the gas refrigerant communication pipe portion G.

  Further, in the present embodiment, there is no information such as the length and the diameter of the refrigerant communication pipe K, and the volume Vlp of the liquid refrigerant communication pipe B3 and the volume Vgp of the gas refrigerant communication pipe G are unknown. As a premise, a case has been described in which the pipe volume determination operation is performed to calculate the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G. This function is used in combination with the function of calculating the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G by inputting information such as the length and the pipe diameter. May be.

  Further, the function of calculating the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G using the above-described pipe volume determination operation and the operation result is not used, and the refrigerant communication pipe part K In the case of using only the function of calculating the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G by inputting information such as length and pipe diameter, the above-described validity determination means (Step S25) may be used to determine whether or not the input information such as the length and the diameter of the refrigerant communication pipe section K is appropriate.

(Step S3: Initial refrigerant quantity detection operation)
When the pipe volume determination operation in step S2 is completed, the process proceeds to the initial refrigerant amount detection operation in step S3. In the initial refrigerant amount detection operation, the processing of step S31 and step S32 shown in FIG. Here, FIG. 9 is a flowchart of the initial refrigerant quantity detection operation.

(Step S31: Refrigerant amount determination operation)
In step S31, similar to the refrigerant amount determination operation in step S11 of the above-described automatic refrigerant charging operation, the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control. Is done. Here, the liquid pipe temperature target value Tlps in the liquid pipe temperature control, the superheat degree target value SHrs in the superheat degree control, and the low pressure target value Pes in the evaporation pressure control are, in principle, the refrigerant amount determination in step S11 of the automatic refrigerant charging operation. The same value as the target value in operation is used.

In this way, the control unit 8 functioning as the refrigerant amount determination operation control means for performing the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control, performs step S31. Is performed.
(Step S32: Calculation of refrigerant amount)
Next, the control circuit 8 functioning as the refrigerant amount calculation means while performing the refrigerant amount determination operation described above, from the refrigerant flowing through the refrigerant circuit 10 in the initial refrigerant amount detection operation in step S32 or the operation state amount of the component device, the refrigerant circuit 10. The amount of refrigerant in is calculated. The refrigerant amount in the refrigerant circuit 10 is calculated using a relational expression between the refrigerant amount in each part of the refrigerant circuit 10 and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device. By the above-described pipe volume determination operation, the volume Vlp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G, which were unknown after installation of the components of the air conditioner 1, are calculated and known. Therefore, by multiplying the volume Vgp of the liquid refrigerant communication pipe part B3 and the volume Vgp of the gas refrigerant communication pipe part G by the refrigerant density, the refrigerant quantity Mlp and the gas refrigerant in the liquid refrigerant communication pipe part B3 are obtained. By calculating the refrigerant amount Mgp of the communication pipe part G and adding the refrigerant amounts of other parts, the initial refrigerant amount of the entire refrigerant circuit 10 can be detected. This initial refrigerant amount is used as a reference refrigerant amount Mi for the entire refrigerant circuit 10 that serves as a reference for determining whether or not there is leakage from the refrigerant circuit 10 in the refrigerant leakage detection operation described later. And stored in the memory of the control unit 8 as the state quantity storage means.

In this way, the control unit 8 that functions as a refrigerant amount calculating means that calculates the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 in the initial refrigerant amount detection operation or the operation state quantity of the component device, performs the steps. The process of S32 is performed.
<Refrigerant leak detection operation mode>
Next, the refrigerant leakage detection operation mode will be described with reference to FIGS. 1, 2, 5, and 10. Here, FIG. 10 is a flowchart of the refrigerant leak detection operation mode.

In the present embodiment, when detecting whether or not the refrigerant has leaked from the refrigerant circuit 10 to the outside due to an unforeseen cause on a regular basis (for example, when it is not necessary to perform air conditioning on holidays or late at night). An example will be described.
(Step S41: refrigerant quantity determination operation)
First, when the operation in the normal operation mode such as the cooling operation and the heating operation described above has passed for a certain time (for example, every six months to one year), the operation mode is automatically or manually switched from the normal operation mode to the refrigerant leakage detection operation mode. Thus, similar to the refrigerant quantity determination operation in the initial refrigerant quantity detection operation, the refrigerant quantity determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed. Here, the liquid pipe temperature target value Tlps in the liquid pipe temperature control, the superheat degree target value SHrs in the superheat degree control, and the low pressure target value Pes in the evaporation pressure control are, in principle, the refrigerant quantity determination operation in the initial refrigerant quantity detection operation. The same value as the target value in step S31 is used.

  This refrigerant amount determination operation is performed for each refrigerant leakage detection operation. For example, the outdoor heat exchanger is different depending on the operating conditions such as when the condensation pressure Pc is different or when refrigerant leakage occurs. Even when the refrigerant temperature Tco at the outlet 22 fluctuates, the liquid pipe temperature control keeps the refrigerant temperature Tlp in the liquid refrigerant communication pipe section B3 constant at the same liquid pipe temperature target value Tlps.

In this way, the control unit 8 functioning as the refrigerant amount determination operation control means for performing the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed in step S41. Is performed.
(Step S42: Calculation of refrigerant amount)
Next, the control unit 8 that functions as the refrigerant amount calculation means while performing the refrigerant amount determination operation described above, determines whether the refrigerant flowing in the refrigerant circuit 10 in the refrigerant leakage detection operation in step S42 or the operation state amount of the component device in the refrigerant circuit 10 Is calculated. The refrigerant amount in the refrigerant circuit 10 is calculated using a relational expression between the refrigerant amount in each part of the refrigerant circuit 10 and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device. Similarly to the initial refrigerant quantity detection operation, the volume Vlp of the liquid refrigerant communication pipe part B3 and the gas refrigerant communication pipe part G, which were unknown after the installation of the components of the air conditioner 1, are performed by the pipe volume determination operation described above. Since the volume Vgp is calculated and known, the liquid refrigerant communication pipe is obtained by multiplying the volume Vgp of the liquid refrigerant communication pipe B3 and the volume Vgp of the gas refrigerant communication pipe G by the refrigerant density. The refrigerant amount Mlp of the refrigerant circuit 10 as a whole can be calculated by calculating the refrigerant amount Mlp of the part B3 and the refrigerant amount Mgp of the gas refrigerant communication pipe part G and further adding the refrigerant amounts of the other parts. .

Here, as described above, since the temperature Tlp of the refrigerant in the liquid refrigerant communication pipe section B3 is kept constant at the same liquid pipe temperature target value Tlps by the liquid pipe temperature control, the refrigerant in the liquid refrigerant communication pipe section B3. The amount Mlp is kept constant even when the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 22 fluctuates regardless of the operating condition of the refrigerant leak detection operation.
In this way, the control unit 8 that functions as the refrigerant amount calculating means for calculating the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 or the operation state quantity of the component device in the refrigerant leak detection operation, causes the step S42. Is performed.

(Steps S43 and S44: Determination of appropriateness of refrigerant amount, warning display)
When the refrigerant leaks from the refrigerant circuit 10 to the outside, the amount of refrigerant in the refrigerant circuit 10 decreases. When the amount of refrigerant in the refrigerant circuit 10 decreases, the degree of supercooling SCo at the outlet of the outdoor heat exchanger 22 tends to decrease, and accordingly, the amount of refrigerant Mc in the outdoor heat exchanger 22 decreases. The refrigerant amount in other parts tends to be kept substantially constant. Therefore, the refrigerant amount M of the entire refrigerant circuit 10 calculated in step S42 described above is based on the reference refrigerant amount Mi detected in the initial refrigerant amount detection operation when refrigerant leakage from the refrigerant circuit 10 occurs. When the refrigerant leakage from the refrigerant circuit 10 does not occur, the reference refrigerant amount Mi becomes almost the same value.

Utilizing this fact, in step S43, it is determined whether or not the refrigerant has leaked. And in step S43, when it determines with the leakage of the refrigerant | coolant from the refrigerant circuit 10 not having arisen, a refrigerant | coolant leakage detection operation mode is complete | finished.
On the other hand, if it is determined in step S43 that refrigerant has leaked from the refrigerant circuit 10, the process proceeds to step S44, and a warning is sent to the warning display unit 9 informing that the refrigerant leak has been detected. After the display, the refrigerant leak detection operation mode is terminated.

In this way, refrigerant leak detection, which is one of the refrigerant quantity determination means, detects whether or not there is a refrigerant leak by determining the appropriateness of the refrigerant quantity in the refrigerant circuit 10 while performing the refrigerant quantity determination operation in the refrigerant leak detection operation mode. The processing of steps S42 to S44 is performed by the control unit 8 functioning as a means.
As described above, in the air conditioner 1 of the present embodiment, the control unit 8 includes the refrigerant amount determination operation unit, the refrigerant amount calculation unit, the refrigerant amount determination unit, the pipe volume determination operation unit, the pipe volume calculation unit, and the validity determination. The refrigerant amount determination system for determining the suitability of the refrigerant amount filled in the refrigerant circuit 10 is configured by functioning as the means and the state quantity accumulation unit.

(3) Features of air conditioner (A)
In this air conditioner 1, when performing the refrigerant amount determination operation with the indoor units 3a to 3c in all the rooms being in the cooling operation state, the high pressure gas refrigerant communication pipe part G1 from the outdoor unit 2 to the connection units 4a to 4c is closed. As a result, the refrigerant condenses and accumulates in the piping, which may increase detection errors. Accordingly, the first bypass refrigerant circuit 27 and the third bypass refrigerant circuits 43a to 43c that bypass the high-pressure gas refrigerant communication pipe part G1 and the low-pressure gas refrigerant communication pipe part G2 are provided, and the first bypass is performed during the refrigerant amount determination operation. By opening the on-off valve V3 and the second bypass on-off valves V13a to V13c, the pressure difference between the high-pressure gas refrigerant communication pipe part G1 and the low-pressure gas refrigerant communication pipe part G2 is reduced, and the high-pressure gas refrigerant communication pipe part Prevents liquid refrigerant from being accumulated due to condensation to G1. For this reason, highly accurate refrigerant quantity determination operation becomes possible. The first bypass on / off valve V3 and the third bypass on / off valve are provided in the outdoor unit 2 and in the connection units 4a to 4c. The first bypass on-off valve V3 is provided in the outdoor unit 2, and the third bypass on-off valve is provided in the connection units 4a to 4c. By using these together, the low-pressure gas refrigerant flows also in the high-pressure gas refrigerant communication pipe section G1. It becomes easy, the temperature change of the gas refrigerant can be minimized, and the detection error can be reduced. In addition, a bypass circuit can be provided in the refrigerant circuit 10 without performing bypass piping work during construction. For this reason, the effort and cost concerning construction can be reduced.

(B)
The air conditioner 1 further includes a temperature sensor in the high-pressure gas refrigerant communication pipe portion G1. For this reason, even if the temperature of the gas refrigerant in the high-pressure gas refrigerant communication pipe section G1 changes due to inflow heat from outside air and the like, and the refrigerant density changes, the refrigerant density can be corrected based on the temperature detection value by the temperature sensor. Become. Therefore, the detection error can be reduced. For this reason, more accurate refrigerant quantity determination operation is possible. Moreover, this air conditioning apparatus 1 is provided with a first high-pressure gas pipe temperature sensor T8 in the heat source unit in the high-pressure gas refrigerant communication pipe section G1, and second high-pressure gas pipe temperature sensors T12a to T12c in the connection units 4a to 4c. Is provided. Therefore, the refrigerant density in the pipe can be corrected with higher accuracy by using the first high-pressure gas pipe temperature sensor T8 and the second high-pressure gas pipe temperature sensors T12a to T12c together. Further, the temperature detecting means can be provided in the refrigerant circuit 10 without providing a temperature sensor in the high-pressure gas refrigerant pipe at the time of construction. For this reason, the effort and cost concerning construction can be reduced.

(4) Other Embodiments Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments and can be changed without departing from the scope of the invention. It is.
(A)
In the above-described embodiment, an example in which the present invention is applied to an air conditioner including one outdoor unit has been described. However, the present invention is not limited to this, and the present invention is applied to an air conditioner including a plurality of outdoor units. It may be applied. Moreover, although the air-cooled outdoor unit which used the external air as the heat source is used as the outdoor unit 2 of the air conditioner 1, a water-cooled or ice heat storage outdoor unit may be used.

(B)
In the above embodiment, the first bypass refrigerant circuit 27 is provided on the outdoor unit 2 side and the third bypass refrigerant circuits 43a to 43c are provided on the connection units 4a to 4c side as the bypass circuit. Only two sides may be sufficient, and only the connection units 4a-4c side may be sufficient.

(C)
In the above-described embodiment, the first high pressure gas pipe temperature sensor T8 is provided on the outdoor unit 2 side and the second high pressure gas pipe temperature sensors T12a to T12c are provided on the connection units 4a to 4c side as temperature sensors. May be only on the outdoor unit 2 side or only on the connection units 4a to 4c side. Further, the temperature sensor may not be provided.

(D)
In the above-described embodiment, the outdoor side control unit 26, the indoor side control units 34a to 34c, and the connection side control units 44a to 44c exchange control signals via the transmission line 8a to control the air conditioner 1 as a whole. However, the present invention is not limited to this, and a control unit that controls the entire air conditioner 1 may be provided in the outdoor unit 2 or in the indoor units 3a to 3c. The connection units 4a to 4c may be provided, or a single unit may be provided as the control unit.

  The air conditioner according to the present invention reduces the pressure difference between the first gas refrigerant communication pipe and the second gas refrigerant communication pipe, prevents liquid refrigerant from being accumulated due to condensation in the first gas refrigerant communication pipe, A highly accurate refrigerant amount determination operation is possible, and it is useful as a refrigerant circuit of an air conditioner and an air conditioner equipped with the refrigerant circuit.

The schematic block diagram of the air conditioning apparatus concerning one Embodiment of this invention. The control block diagram of an air conditioning apparatus. Flowchart of test operation mode. The flowchart of a refrigerant | coolant automatic charging operation. The schematic diagram which shows the state of the refrigerant | coolant which flows through the refrigerant circuit in refrigerant | coolant amount determination driving | operation (illustration of a four-way switching valve etc. is abbreviate | omitted). The flowchart of piping volume determination driving | operation. The Mollier diagram which shows the refrigerating cycle of the air conditioning apparatus in the pipe | tube volume determination driving | operation for liquid refrigerant communication piping. The Mollier diagram which shows the refrigerating cycle of the air conditioning apparatus in the pipe volume determination driving | operation for gas refrigerant | coolant communication piping. The flowchart of an initial refrigerant quantity detection driving | operation. The flowchart of a refrigerant | coolant leak detection operation mode.

Explanation of symbols

1 Air conditioner 2 Outdoor unit (heat source unit)
21 Compressor (compression means)
22 Outdoor heat exchanger (heat source side heat exchanger)
27 First bypass refrigerant circuit (bypass circuit)
3a-3c Indoor unit (Usage unit)
31a-31c Indoor heat exchanger (use side heat exchanger)
4a to 4c Connection unit (switching mechanism / switching unit)
43a to 43c third bypass refrigerant circuit (bypass circuit)
8 control unit V3 first bypass on-off valve (bypass circuit on-off means)
V13a to V13c Second bypass opening / closing valve (bypass circuit opening / closing means)
T8 First high-pressure gas pipe temperature sensor (temperature detection means)
T12a to T12c Second high pressure gas pipe temperature sensor (temperature detection means)

Claims (6)

An air conditioner (1) that performs a refrigerant amount determination operation for determining a refrigerant amount in a refrigerant circuit,
A heat source unit (2) including a compression means (21) for compressing the refrigerant gas and a heat source side heat exchanger (22);
Utilization units (3a-3c) including utilization side heat exchangers (31a-31b);
An expansion mechanism (V2, V9a to V9c);
A first gas refrigerant pipe (46a to 46c, 52, 92) extending from the discharge side of the compression means to the utilization unit;
Second gas refrigerant pipes (47a to 47c, 53, 93) extending from the suction side of the compression means to the utilization unit;
Liquid refrigerant piping (35a to 35c, 45a to 45c, 51, 91) extending from the heat source side heat exchanger to the utilization unit;
A first state in which the refrigerant flowing in the liquid refrigerant pipe evaporates in the use side heat exchanger and then flows into the second gas refrigerant pipe, and the refrigerant flowing in the first gas refrigerant pipe is in the use side heat exchanger. A switching mechanism (4a-4c) capable of switching between a second state flowing into the liquid refrigerant pipe after being condensed;
A bypass circuit (27, 43a to 43c) for bypassing the first gas refrigerant pipe and the second gas refrigerant pipe;
Bypass circuit opening / closing means (V3, V13a to V13c) provided on the bypass circuit for opening and closing the bypass circuit;
A controller (8) for opening the bypass circuit opening / closing means before performing the refrigerant quantity determination operation;
An air conditioner (1) comprising: The bypass circuit opening / closing means (V3) is provided in the heat source unit.
The air conditioner (1) according to claim 1. A switching unit (4a-4c) separate from the utilization unit and the heat source unit is further provided,
The switching unit has the switching mechanism,
The bypass circuit opening / closing means (V13a to V13c) is provided in the switching unit.
The air conditioner (1) according to claim 1 or 2. Temperature detecting means (T8, T12a to T12c) for detecting a refrigerant temperature in the first gas refrigerant pipe and outputting a refrigerant temperature detection value;
The controller corrects the determined refrigerant amount determined by the refrigerant amount determination operation based on the refrigerant temperature detection value.
The air conditioner (1) according to any one of claims 1 to 3. The temperature detecting means (T8) is provided in the switching unit.
The air conditioner (1) according to claim 4. The temperature detecting means (T12a to T12c) is provided in the heat source unit.
The air conditioner (1) according to claim 4 or 5.

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