WO2018003096A1

WO2018003096A1 - Air-conditioning device

Info

Publication number: WO2018003096A1
Application number: PCT/JP2016/069539
Authority: WO
Inventors: 博幸岡野
Original assignee: 三菱電機株式会社
Priority date: 2016-06-30
Filing date: 2016-06-30
Publication date: 2018-01-04
Also published as: GB201817754D0; GB2564995B; GB2564995A; JP6636151B2; JPWO2018003096A1

Abstract

This air-conditioning device comprises: a heat source unit that has a compressor, a flow path switching valve, and a heat-source-side heat exchanger; a plurality of indoor units that have load-side heat exchangers and perform cooling operations or heating operations; a low-pressure pipe and a high-pressure pipe that connect the heat source unit and the indoor units; a relay unit that has a first branch portion, which has first opening-closing valves which are switched to connect one end of the load-side heat exchangers to the low-pressure pipe, and second opening-closing valves which are switched to connect said ends of the load-side heat exchangers to the high-pressure pipe, and a second branch portion, which connects the other end of the load-side heat exchangers to the high-pressure pipe through first expansion valves and to a medium-pressure return pipe through second expansion valves; a leakage detection unit that detects leakage of a refrigerant; and a control device that controls the first expansion valves and the second expansion valves. The control device performs pump down operation for closing all the first expansion valves and the second expansion valves and recovering the refrigerant to the heat source unit when the leakage of the refrigerant is detected by the leakage detection unit.

Description

Air conditioner

The present invention relates to an air conditioner having a relay that distributes a refrigerant supplied from a heat source unit to a plurality of indoor units.

Conventionally, in an air conditioner using a refrigeration cycle such as a heat pump cycle, a heat source unit having a compressor and a heat source side heat exchanger and an indoor unit having an expansion valve and a load side heat exchanger are connected by a pipe, and the refrigerant is It has a flowing refrigerant circuit. When the refrigerant evaporates or condenses in the load-side heat exchanger, the air conditioner absorbs heat or dissipates heat from the air in the air-conditioning space that is the heat exchange target, and changes the pressure and temperature of the refrigerant flowing in the refrigerant circuit. Air conditioning is performed while There has also been proposed an air conditioner including a heat source unit, a plurality of indoor units, and a relay unit that distributes the refrigerant supplied from the heat source unit to the plurality of indoor units. In such an air conditioner, whether or not a cooling operation or a heating operation is necessary in each of a plurality of indoor units is automatically determined according to a set temperature of a remote controller attached to the indoor unit and a temperature around the indoor unit. Thus, the cooling / heating simultaneous operation in which the cooling operation or the heating operation is performed for each indoor unit is performed.

In recent years, from the viewpoint of preventing global warming and the impact on human bodies due to leakage of flammable refrigerant into the room and preventing combustion, it is necessary to take safety measures against refrigerant leakage. There has been proposed an air conditioner in which the above measures have been taken (see, for example, Patent Document 1).
In Patent Document 1, in an air conditioner that performs simultaneous cooling and heating operations, a valve device is newly provided between the relay machine and the indoor unit, and when the refrigerant leaks, the valve device is closed, Prevents refrigerant from leaking outside the indoor unit.

Japanese Patent No. 4076753

However, the air conditioner disclosed in Patent Document 1 requires a new valve device between the relay unit and the indoor unit in order to prevent the refrigerant from leaking outside the indoor unit. Or the cost becomes high as a system. In addition, there is a problem that if the valve is only closed to prevent leakage of the refrigerant, it takes time to recover the refrigerant when the device is repaired thereafter.

The present invention has been made to solve the above-described problems, and provides an air conditioner that can suppress the leakage of the refrigerant and reduce the time for collecting the refrigerant with an inexpensive configuration. is there.

An air conditioner according to the present invention includes a compressor, a flow path switching valve, a heat source device having a heat source side heat exchanger, and a plurality of indoor units having a load side heat exchanger and performing a cooling operation or a heating operation. A first on-off valve that switches one of the load side heat exchangers to be connected to the low-pressure pipe, and a low-pressure pipe and a high-pressure pipe that connect the heat source machine and each indoor unit, and A first branch portion having a second on-off valve that switches the one of the load-side heat exchangers to be connected to the high-pressure pipe, and the other of the load-side heat exchangers is connected to a first expansion valve. A relay having a second branching portion connected to the high-pressure liquid pipe through the second expansion valve and connected to the return intermediate pressure pipe, a leakage detection unit for detecting refrigerant leakage, and the first And a control device for controlling the second expansion valve. After detecting refrigerant leakage by parts, and performs pump down operation for collecting the refrigerant into the heat source apparatus by closing all of the first expansion valve and the second expansion valve.

The air conditioner according to the present invention includes a leakage detection unit that detects refrigerant leakage. When the leakage detection unit detects refrigerant leakage, the control device closes all expansion valves and performs pump-down operation. And recover the refrigerant to the heat source machine side. In other words, when refrigerant leakage is detected, the indoor unit is shut off by the expansion valve to suppress the refrigerant leakage to the outside of the indoor unit, and the refrigerant is recovered from the indoor unit to the heat source unit side. Can be shortened. Further, since it is not necessary to provide a new valve in addition to the expansion valve in order to suppress the leakage of the refrigerant to the outside of the indoor unit, an inexpensive configuration can be achieved.

It is a refrigerant circuit figure showing the air harmony device concerning an embodiment of the invention. It is a refrigerant circuit figure which shows the state at the time of the cooling operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit figure which shows the state at the time of the heating only operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit diagram which shows the state at the time of the cooling main operation | movement of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit figure showing the state at the time of heating main operation of the air harmony device concerning an embodiment of the invention. It is a flowchart which shows the operation | movement at the time of the refrigerant | coolant leakage detection of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit figure showing the state at the time of pump down operation of the air harmony device concerning an embodiment of the invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings, the relationship of the size of each component may be different from the actual one.

Embodiment.
Hereinafter, embodiments of an air-conditioning apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a refrigerant circuit diagram showing an air conditioner 1 according to an embodiment of the present invention.
Hereinafter, the structure of the air conditioning apparatus 1 which concerns on this Embodiment is demonstrated using FIG.
As shown in FIG. 1, the air-conditioning apparatus 1 includes a heat source unit 100, a plurality of

indoor units

300a and 300b, a relay unit 200, and a control unit 10.

In the present embodiment, the case where two

indoor units

300a and 300b are connected to one heat source unit 100 is illustrated, but the number of heat source units 100 may be two or more. The number of

indoor units

300a and 300b may be three or more.

As shown in FIG. 1, the air conditioner 1 includes a heat source device 100,

indoor units

300 a and 300 b, and a relay device 200 connected by a pipe to configure a refrigerant circuit in which a refrigerant circulates.
The heat source unit 100 has a function of supplying hot or cold to the two

indoor units

300a and 300b. The two

indoor units

300a and 300b are connected in parallel to each other and have the same configuration.

The

indoor units

300a and 300b have a function of cooling or heating an air-conditioning target space such as a room by using heat or cold supplied from the heat source device 100.
The repeater 200 is interposed between the heat source unit 100 and the

indoor units

300a and 300b, and has a function of switching the flow of refrigerant supplied from the heat source unit 100 in response to a request from the

indoor units

300a and 300b. .

The air conditioner 1 also includes a load capacity detection unit 20 that detects the heating / cooling load capacity of the plurality of

indoor units

300a and 300b. Here, the cooling / heating load capacity is a cooling load capacity and a heating load capacity in the plurality of

indoor units

300a and 300b. The load capacity detection unit 20 includes liquid tube

temperature detection units

303a and 303b and gas tube

temperature detection units

304a and 304b.

The heat source unit 100 and the relay unit 200 are connected on the high-pressure side by a high-pressure pipe 402 through which a high-pressure refrigerant flows, and on the low-pressure side by a low-pressure pipe 401 through which a low-pressure refrigerant flows. Further, the repeater 200 and the

indoor units

300a and 300b are connected by

gas branch pipes

403a and 403b, respectively. A gas-state refrigerant mainly flows through the

gas branch pipes

403a and 403b. Moreover, the relay machine 200 and the

indoor units

300a and 300b are connected by

liquid branch pipes

404a and 404b, respectively. A liquid refrigerant mainly flows through the

liquid branch pipes

404a and 404b.

(Heat source machine 100)
The heat source device 100 has a function of supplying warm or cold to the

indoor units

300a and 300b.
The heat source unit 100 is connected to a variable capacity compressor 101, a flow path switching valve 102 that switches a direction in which the refrigerant flows in the heat source unit 100, a heat source side heat exchange unit 120, and a suction side of the compressor 101, and is in a liquid state. An accumulator 104 that stores the refrigerant and a heat source side flow path adjustment unit 140 that restricts the direction in which the refrigerant flows.
The flow path switching valve 102 is illustrated as a four-way valve, but may be configured by combining a two-way valve or a three-way valve.

The heat source side heat exchange unit 120 includes a main pipe 114, a heat source side heat exchanger 103, and a heat source side blower 112.
The heat source side heat exchanger 103 functions as an evaporator or a condenser. The heat source side heat exchanger 103 is for exchanging heat between the refrigerant and the outdoor air in the case of the air cooling type, and for exchanging heat between the refrigerant and water or brine in the case of the water cooling type.

The heat source side blower 112 varies the amount of air blown to the heat source side heat exchanger 103 and controls the heat exchange capacity.
One of the main pipes 114 is connected to the flow path switching valve 102 and the other is connected to the high-pressure pipe 402, and the heat source side heat exchanger 103 is provided in the middle.

The heat source side flow path adjustment unit 140 includes a third check valve 105, a fourth check valve 106, a fifth check valve 107, and a sixth check valve 108.
The third check valve 105 is provided in a pipe connecting the heat source side heat exchange unit 120 and the high pressure pipe 402 and allows the refrigerant to flow from the heat source side heat exchange unit 120 toward the high pressure pipe 402.
The fourth check valve 106 is provided in a pipe connecting the flow path switching valve 102 of the heat source apparatus 100 and the low pressure pipe 401, and allows the refrigerant to flow from the low pressure pipe 401 toward the flow path switching valve 102.

The fifth check valve 107 is provided in a pipe connecting the flow path switching valve 102 and the high pressure pipe 402 of the heat source device 100 and allows the refrigerant to flow from the flow path switching valve 102 toward the high pressure pipe 402.
The sixth check valve 108 is provided in a pipe connecting the heat source side heat exchange unit 120 and the low pressure pipe 401, and allows the refrigerant to flow from the low pressure pipe 401 toward the heat source side heat exchange unit 120.

Further, the heat source apparatus 100 is provided with a discharge pressure detection unit 126 and a suction pressure detection unit 127.
The discharge pressure detection unit 126 is provided in a pipe connecting the flow path switching valve 102 and the discharge side of the compressor 101, and detects the discharge pressure of the compressor 101. The discharge pressure detection unit 126 includes, for example, a pressure sensor and transmits a detected discharge pressure signal to the control device 10.
The discharge pressure detection unit 126 may have a storage device or the like. In this case, the discharge pressure detection unit 126 accumulates the detected discharge pressure data in a storage device or the like for a predetermined period, and transmits a signal including the discharge pressure data detected every predetermined cycle to the control device 10.

The suction pressure detection unit 127 is provided in a pipe connecting the flow path switching valve 102 and the accumulator 104 and detects the suction pressure of the compressor 101. The suction pressure detection unit 127 includes a pressure sensor, for example, and transmits a signal of the detected suction pressure to the control device 10.
Note that the suction pressure detection unit 127 may include a storage device or the like. In this case, the suction pressure detection unit 127 accumulates the detected suction pressure data in a storage device or the like for a predetermined period, and transmits a signal including the suction pressure data detected every predetermined cycle to the control device 10.

(

Indoor units

300a, 300b)
The

indoor units

300a and 300b include load-

side heat exchangers

301a and 301b that function as condensers or evaporators, respectively.

The

indoor units

300a and 300b are provided with gas

pipe temperature detectors

304a and 304b and liquid

pipe temperature detectors

303a and 303b, respectively.
The gas pipe

temperature detection units

304a and 304b are respectively provided between one of the load

side heat exchangers

301a and 301b and the relay machine 200, and connect the load

side heat exchangers

301a and 301b and the relay machine 200, respectively. The temperature of the refrigerant flowing in the

gas branch pipes

403a and 403b is detected. The gas pipe

temperature detection units

304 a and 304 b are configured by, for example, a thermistor and transmit a detected temperature signal to the control device 10.

Note that the gas pipe

temperature detection units

304a and 304b may have a storage device or the like. In this case, the gas pipe

temperature detection units

304a and 304b accumulate the detected temperature data in a storage device or the like for a predetermined period, and transmit a signal including the detected temperature data for each predetermined period to the control device 10. .

The liquid pipe

temperature detection units

303a and 303b are respectively provided between the other of the load

side heat exchangers

301a and 301b and the relay machine 200, and connect the load

side heat exchangers

301a and 301b and the relay machine 200, respectively. The temperature of the refrigerant flowing through the

liquid branch pipes

404a and 404b is detected. The liquid tube

temperature detection units

303 a and 303 b are configured by, for example, a thermistor and transmit a detected temperature signal to the control device 10.

Note that the liquid tube

temperature detection units

303a and 303b may have a storage device or the like. In this case, the liquid tube

temperature detection units

303a and 303b accumulate the detected temperature data in a storage device or the like for a predetermined period, and transmit a signal including the detected temperature data for each predetermined period to the control device 10. .

(Repeater 200)
The relay unit 200 is interposed between the heat source unit 100 and the

indoor units

300a and 300b, switches the flow of the refrigerant supplied from the heat source unit 100 in response to a request from the

indoor units

300a and 300b, and supplies it from the heat source unit 100 The refrigerant to be distributed is distributed to the plurality of

indoor units

300a and 300b.
The relay machine 200 includes a first branch part 240, a second branch part 250, a gas-liquid separator 201, a relay bypass pipe 209, a high pressure gas pipe 402A, a high pressure liquid pipe 402B, and a return intermediate pressure pipe 401A. A liquid outflow side flow rate adjustment valve 204, a heat exchange unit 26, and a relay bypass flow rate adjustment valve 205.

One of the first branch parts 240 is connected to the

gas branch pipes

403a and 403b, and the other is connected to the low pressure pipe 401 and the high pressure gas pipe 402A. The refrigerant flow direction during the cooling operation and the refrigerant flow during the heating operation. The direction is different. The first branching section 240 includes

heating solenoid valves

202a and 202b and cooling

solenoid valves

203a and 203b.

One of the

heating solenoid valves

202a and 202b is connected to the

gas branch pipes

403a and 403b and the other is connected to the high-pressure gas pipe 402A, and is opened during the heating operation and closed during the cooling operation. It is.
Each of the cooling

electromagnetic valves

203a and 203b is connected to the

gas branch pipes

403a and 403b and the other is connected to the low pressure pipe 401, and is opened during the cooling operation and closed during the heating operation. is there.

The cooling

electromagnetic valves

203a and 203b correspond to the “first on-off valve” of the present invention, and the heating

electromagnetic valves

202a and 202b correspond to the “second on-off valve” of the present invention.

One of the second branch parts 250 is connected to the

liquid branch pipes

404a and 404b, and the other is connected to the return intermediate pressure pipe 401A and the high pressure liquid pipe 402B. The refrigerant flow direction during the cooling operation and the refrigerant flow during the heating operation are connected. The distribution direction is different. The second branch portion 250 includes

first expansion valves

210a and 210b and

second expansion valves

211a and 211b.

The

first expansion valves

210a and 210b and the

second expansion valves

211a and 211b have a function of adjusting the flow rate of the refrigerant flowing through the

indoor units

300a and 300b. The

first expansion valves

210a and 210b and the

second expansion valves

211a and 211b are configured by, for example, electric expansion valves with variable opening degrees.

One of the

first expansion valves

210a and 210b is connected to the

liquid branch pipes

404a and 404b, and the other of the

first expansion valves

210a and 210b is connected to the high-pressure liquid pipe 402B. During the cooling operation, the load-

side heat exchangers

301a and 210b are connected. The degree of opening is controlled in order to control the superheat amount on the outlet side of 301b.
One of the

second expansion valves

211a and 211b is connected to the

liquid branch pipes

404a and 404b, and the other of the

second expansion valves

211a and 211b is connected to the return intermediate pressure pipe 401A. During the heating operation, the load-side heat exchangers 301a, The degree of opening is controlled to control the amount of subcooling on the outlet side of 301b.

Each of the

indoor units

300a and 300b has a function of cooling or heating an air-conditioning target space such as a room by using heat or cold supplied from the heat source device 100.
The gas-liquid separator 201 separates the refrigerant in the gas state and the refrigerant in the liquid state, the inflow side is connected to the high pressure pipe 402, and the gas outflow side is connected to the first branch 240 through the high pressure gas pipe 402A. The liquid outlet side is connected to the second branch 250 through the high-pressure liquid pipe 402B.
The relay bypass pipe 209 connects the second branch 250 and the low pressure pipe 401 with the high pressure liquid pipe 402B.

The liquid outflow side flow rate adjustment valve 204 is connected to the liquid outflow side of the gas-liquid separator 201, and is composed of, for example, an electric expansion valve with variable opening. The liquid outflow-side flow rate adjustment valve 204 adjusts the flow rate of the liquid refrigerant flowing out of the gas-liquid separator 201.

The heat exchange unit 26 includes a first heat exchange unit 206 and a second heat exchange unit 207.
The first heat exchanging unit 206 is provided in a pipe between the liquid outflow side of the gas-liquid separator 201 and the liquid outflow side flow rate adjustment valve 204 and the relay bypass pipe 209. The first heat exchanging unit 206 exchanges heat between the liquid refrigerant flowing out of the gas-liquid separator 201 and the refrigerant flowing through the relay bypass pipe 209 toward the low pressure pipe 401.
The second heat exchange unit 207 is provided in the pipe on the downstream side of the liquid outflow side flow rate adjustment valve 204 and the relay bypass pipe 209. The second heat exchange unit 207 exchanges heat between the refrigerant that has flowed out of the liquid outflow side flow rate adjustment valve 204 and the refrigerant that flows through the relay bypass pipe 209 toward the low-pressure pipe 401.

The relay bypass flow rate adjustment valve 205 is connected to the upstream side of the second heat exchanging unit 207 in the relay bypass pipe 209, and is configured by, for example, an electric expansion valve having a variable opening. The relay bypass flow rate adjustment valve 205 adjusts the flow rate of the refrigerant flowing into the relay bypass pipe 209 out of the refrigerant flowing out from the second heat exchange unit 207.

Further, the relay machine 200 is provided with a first liquid outflow pressure detection unit 231, a second liquid outflow pressure detection unit 232, and a relay bypass temperature detection unit 208.
The first liquid outflow pressure detection unit 231 is provided between the first heat exchange unit 206 and the liquid outflow side flow rate adjustment valve 204 and detects the pressure of the refrigerant on the liquid outflow side of the gas-liquid separator 201. Is. The first liquid outflow pressure detection unit 231 includes, for example, a pressure sensor, and transmits a detected pressure signal to the control device 10. Note that the first liquid outflow pressure detector 231 may include a storage device or the like. In this case, the first liquid outflow pressure detection unit 231 accumulates the detected pressure data in a storage device or the like for a predetermined period, and transmits a signal including the detected pressure data for each predetermined period to the control device 10. .

The second liquid outflow pressure detection unit 232 is provided between the liquid outflow side flow rate adjustment valve 204 and the second heat exchange unit 207, and detects the pressure of the refrigerant flowing out of the liquid outflow side flow rate adjustment valve 204. Is. The second liquid outflow pressure detection unit 232 includes, for example, a pressure sensor and transmits a detected pressure signal to the control device 10. The second liquid outflow pressure detection unit 232 may include a storage device or the like. In this case, the second liquid outflow pressure detector 232 accumulates the detected pressure data in a storage device or the like for a predetermined period, and transmits a signal including the detected pressure data for each predetermined period to the control device 10. .

Here, the liquid outflow side flow rate adjustment valve 204 has an opening degree so that the difference between the pressure detected by the first liquid outflow pressure detection unit 231 and the pressure detected by the second liquid outflow pressure detection unit 232 is constant. Has been adjusted.

The relay bypass temperature detector 208 is provided in the relay bypass pipe 209 and detects the pressure of the refrigerant flowing through the relay bypass pipe 209. The relay bypass temperature detection unit 208 is configured by, for example, a thermistor and transmits a detected temperature signal to the control device 10. The relay bypass temperature detection unit 208 may have a storage device or the like. In this case, the relay bypass temperature detection unit 208 accumulates the detected temperature data in a storage device or the like for a predetermined period, and transmits a signal including the detected temperature data for each predetermined period to the control device 10.

Here, the relay bypass flow rate adjustment valve 205 is detected by the pressure detected by the first liquid outflow pressure detector 231, the pressure detected by the second liquid outflow pressure detector 232, and the relay bypass temperature detector 208. The opening degree is adjusted based on at least one of the measured temperatures.

(Refrigerant)
In the air conditioner 1, a refrigerant is filled in a pipe. As the refrigerant, for example, natural refrigerant such as carbon dioxide (CO ₂ ), hydrocarbon, helium, HFC410A, combustible R32 refrigerant, or the like is used. In addition, the inside of the piping of the air conditioning apparatus 1 may be filled with a heat medium instead of the refrigerant. The heat medium is, for example, water, brine or the like.

(Leakage detection part)
The leak detection unit 400 is a refrigerant leak detection unit that detects a refrigerant leak and outputs a signal. For example, a change in resistance value that occurs when a metal oxide semiconductor comes into contact with the refrigerant gas is detected in the refrigerant gas in the air. This is a semiconductor gas sensor that detects the concentration. In addition, it may be other than a semiconductor gas sensor, for example, a non-dispersive infrared sensor that detects the amount of infrared rays absorbed by the gas, a refrigerant gas concentration cannot be measured, but a detector that can detect the presence or absence of a refrigerant gas, An oxygen concentration meter or the like that measures the oxygen concentration in the room may be used. Information that the leakage of the refrigerant is detected by the leakage detector 400 is transmitted to the control device 10 and is used as a trigger for the pump-down operation.

In addition, in this Embodiment, although it is the structure provided with the one leak detection part 400 with respect to all the systems, it is not limited to it, The leak detection part 400 is 1: for each indoor unit or each living room. If it is set as the structure provided by 1 relationship, it can be judged in which indoor unit system or which living room system the refrigerant | coolant leaked.

(Control device 10)
The control device 10 controls the entire system of the air conditioner 1, and is configured by a microprocessor unit including, for example, a CPU and a memory. The control device 10 includes gas pipe

temperature detection units

304a and 304b, liquid pipe

temperature detection units

303a and 303b, a first liquid outflow pressure detection unit 231, a second liquid outflow pressure detection unit 232, a relay bypass temperature detection unit 208, and a discharge pressure. Based on the detection information received from the detection unit 126 and the suction pressure detection unit 127 and the instruction from the remote controller (not shown), the drive frequency of the compressor 101, the rotation speed of the heat source side blower 112, the load side heat The number of rotations of an indoor fan (not shown) provided in the

exchangers

301a and 301b, switching of the flow path switching valve 102, opening and closing of the

heating solenoid valves

202a and 202b and the cooling

solenoid valves

203a and 203b, the first Control the opening degree of the

expansion valves

210a and 210b, the

second expansion valves

211a and 211b, the liquid outflow side flow rate adjustment valve 204, and the relay bypass flow rate adjustment valve 205.

In addition, although the control apparatus 10 is comprised by the 1st control apparatus 141 provided in the heat-source equipment 100, and the 2nd control apparatus 220 provided in the relay machine 200, it is not limited to this, A heat-source equipment 100,

indoor units

300a, 300b, and repeater 200 may be installed only, or may be installed in all of them. Further, the control device 10 may be mounted separately from the heat source unit 100, the

indoor units

300a and 300b, and the relay unit 200. Note that the first control device 141 and the second control device 220 are communicably connected to each other by wireless or wired communication, and can transmit and receive various data. Furthermore, the control device 10 may be configured by a single control device.

Further, the control device 10 includes a storage unit 11 and a setting unit 12. In the present embodiment, the storage unit 11 and the setting unit 12 are provided in the heat source unit 100, but may be provided in addition to the heat source unit 100. Further, the storage unit 11 and the setting unit 12 may be provided separately from the control device 10.

The storage unit 11 stores data necessary for the control device 10 to perform processing temporarily or for a long period of time, and includes, for example, a memory.
The setting means 12 has a function of determining whether the air conditioner 1 is a cooling main operation or a heating main operation. Further, the setting unit 12 has a function of determining whether or not the condensation target temperature of the heat source side heat exchanger 103 is equal to or higher than the condensation target temperature threshold in the cooling main operation. The setting means 12 calculates the heating / cooling load capacity from the number of indoor units that are performing the cooling operation and the number of indoor units that are performing the heating operation among the plurality of

indoor units

300a and 300b. Also good. The setting unit 12 may calculate the heating / cooling load capacity from the discharge pressure detected by the discharge pressure detection unit 126 or the suction pressure detected by the suction pressure detection unit 127. In this case, the discharge pressure detection unit 126 or the suction pressure detection unit 127 is a component of the load capacity detection unit 20.

Next, the operation of the air conditioner 1 will be described.
The air conditioner 1 includes a cooling only operation, a heating only operation, a cooling main operation, and a heating main operation as operation modes.
The all cooling operation is a mode in which all the

indoor units

300a and 300b perform the cooling operation.
The all heating operation is a mode in which all the

indoor units

300a and 300b perform the heating operation.
The cooling main operation is a mode in which the capacity of the cooling operation is larger than the capacity of the heating operation among the simultaneous cooling and heating operations.
The heating main operation is a mode in which the heating operation capacity is larger than the cooling operation capacity in the simultaneous cooling and heating operation.

(Cooling only)
FIG. 2 is a refrigerant circuit diagram illustrating a state during a cooling only operation of the air-conditioning apparatus 1 according to the embodiment of the present invention. In FIG. 2, the high-pressure refrigerant is indicated by a solid line arrow, and the low-pressure refrigerant is indicated by a broken line arrow. The same applies to FIGS. 3 to 5 described later.
First, the cooling only operation of the air conditioner 1 will be described with reference to FIG. In the all-cooling operation, in the air conditioner 1, all the

indoor units

300a and 300b are performing the cooling operation.
As shown in FIG. 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102 and is heat-exchanged with outdoor air blown by the heat-source side blower 112 in the heat-source side heat exchanger 103. To condense. The condensed and liquefied refrigerant passes through the third check valve 105 and the high-pressure pipe 402 and reaches the gas-liquid separator 201 of the repeater 200.

The refrigerant is separated into a gaseous refrigerant and a liquid refrigerant by the gas-liquid separator 201. The liquid refrigerant flowing out from the liquid outflow side of the gas-liquid separator 201 passes through the first heat exchange unit 206, the liquid outflow side flow rate adjustment valve 204, the second heat exchange unit 207, and the high pressure liquid pipe 402B. The second branching section 250 is reached and branches there. The branched refrigerant flows into the

indoor units

300a and 300b through the

first expansion valves

210a and 210b and the

liquid branch pipes

404a and 404b, respectively.

The refrigerant that has flowed into the

indoor units

300a and 300b is depressurized to a low pressure by the

first expansion valves

210a and 210b controlled by the superheat amount on the outlet side of the load

side heat exchangers

301a and 301b, respectively. The decompressed refrigerant flows into the load-

side heat exchangers

301a and 301b, and is heat-exchanged with indoor air in the load-

side heat exchangers

301a and 301b to be evaporated. At that time, the entire room is cooled. Then, the refrigerant in a gas state passes through the

gas branch pipes

403a and 403b and the cooling

electromagnetic valves

203a and 203b of the first branch portion 240, and then merges and passes through the low pressure pipe 401.

Also, a part of the refrigerant that has passed through the second heat exchange unit 207 flows into the relay bypass pipe 209. The refrigerant flowing into the relay bypass pipe 209 is decompressed to a low pressure by the relay bypass flow rate adjustment valve 205, and then passes through the liquid outflow side flow rate adjustment valve 204 in the second heat exchange unit 207, that is, the relay bypass. Heat exchange with the refrigerant before branching to the pipe 209 evaporates. Further, in the first heat exchange unit 206, the refrigerant is evaporated by exchanging heat with the refrigerant before flowing into the liquid outflow side flow rate adjustment valve 204. The evaporated refrigerant flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling

electromagnetic valves

203a and 203b. Thereafter, the merged refrigerant passes through the fourth check valve 106, the flow path switching valve 102, and the accumulator 104 and is sucked into the compressor 101.

In the cooling only operation, the

heating solenoid valves

202a and 202b are closed. The cooling

electromagnetic valves

203a and 203b are opened. Since the low pressure pipe 401 is low pressure and the high pressure pipe 402 is high pressure, the refrigerant flows through the third check valve 105 and the fourth check valve 106. Further, the

second expansion valves

211a and 211b are closed so that no refrigerant flows.

(All heating operation)
FIG. 3 is a refrigerant circuit diagram illustrating a state of the air-conditioning apparatus 1 according to the embodiment of the present invention during a heating only operation.
Next, the heating only operation of the air conditioner 1 will be described with reference to FIG. In the all heating operation, in the air conditioner 1, all the

indoor units

300a and 300b perform the heating operation.
As shown in FIG. 3, the high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102, passes through the fifth check valve 107 and the high-pressure pipe 402, and the gas-liquid of the relay machine 200. The separator 201 is reached.

The refrigerant is separated into a gaseous refrigerant and a liquid refrigerant by the gas-liquid separator 201. The gaseous refrigerant that has flowed out from the gas outflow side of the gas-liquid separator 201 passes through the high-pressure gas pipe 402A, reaches the first branching section 240, and branches there. The branched refrigerant flows into the

indoor units

300a and 300b through the

heating solenoid valves

202a and 202b and the

gas branch pipes

403a and 403b, respectively.

The refrigerant that has flowed into the

indoor units

300a and 300b undergoes heat exchange with the indoor air in the load-

side heat exchangers

301a and 301b, respectively, and is condensed and liquefied. At that time, the entire room is heated. The condensed and liquefied refrigerant passes through the

second expansion valves

211a and 211b controlled by the subcool amounts on the outlet side of the load

side heat exchangers

301a and 301b, respectively.

The refrigerant that has passed through the

second expansion valves

211a and 211b passes through the return intermediate pressure pipe 401A and the second heat exchange unit 207, flows into the relay bypass pipe 209, and is reduced to a low pressure by the relay bypass flow rate adjustment valve 205. In the second heat exchange unit 207, heat is exchanged with the refrigerant that has passed through the liquid outflow side flow rate adjustment valve 204, that is, the refrigerant before branching to the relay bypass pipe 209, and evaporates. Further, in the first heat exchange unit 206, the refrigerant is evaporated by exchanging heat with the refrigerant before flowing into the liquid outflow side flow rate adjustment valve 204. The evaporated refrigerant flows into the low pressure pipe 401, passes through the sixth check valve 108, undergoes heat exchange with the outdoor air blown by the heat source side blower 112 in the heat source side heat exchanger 103, and evaporates into gas. The gasified refrigerant passes through the flow path switching valve 102 and the accumulator 104 and is sucked into the compressor 101.

In the all heating operation, the

heating solenoid valves

202a and 202b are opened. The cooling

electromagnetic valves

203a and 203b are closed. In addition, since the low pressure pipe 401 has a low pressure and the high pressure pipe 402 has a high pressure, the refrigerant flows through the fifth check valve 107 and the sixth check valve 108. In addition, the liquid outflow side flow rate adjustment valve 204 is closed. Further, the

first expansion valves

210a and 210b are closed so that the refrigerant does not flow.

(Cooling operation)
FIG. 4 is a refrigerant circuit diagram illustrating a state during the cooling main operation of the air-conditioning apparatus 1 according to the embodiment of the present invention.
Next, the cooling main operation of the air conditioner 1 will be described with reference to FIG. In the cooling main operation, the air conditioner 1 has a cooling request from the indoor unit 300a and a heating request from the indoor unit 300b.
As shown in FIG. 4, the high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102, and is heat-exchanged with outdoor air blown by the heat source side blower 112 in the heat source side heat exchanger 103. To condense. The condensed and liquefied refrigerant passes through the third check valve 105 and the high-pressure pipe 402 and reaches the gas-liquid separator 201 of the repeater 200.

The refrigerant is separated into a gaseous refrigerant and a liquid refrigerant by the gas-liquid separator 201. The liquid refrigerant flowing out from the liquid outflow side of the gas-liquid separator 201 passes through the first heat exchange unit 206, the liquid outflow side flow rate adjustment valve 204, the second heat exchange unit 207, and the high pressure liquid pipe 402B. 2 branching section 250 is reached. And a refrigerant | coolant flows in into the indoor unit 300a through the 1st expansion valve 210a of the 2nd branch part 250, and the liquid branch pipe 404a.

The refrigerant flowing into the indoor unit 300a is depressurized to a low pressure by controlling the superheat on the outlet side of the load-side heat exchanger 301a by the first expansion valve 210a. The decompressed refrigerant flows into the load-side heat exchanger 301a, and is heat-exchanged with indoor air in the load-side heat exchanger 301a to be evaporated and gasified. At that time, the room in which the indoor unit 300a is installed is cooled. The refrigerant in a gas state flows into the low-pressure pipe 401 through the gas branch pipe 403a and the cooling electromagnetic valve 203a of the first branch 240.

On the other hand, the gaseous refrigerant flowing out from the gas outflow side of the gas-liquid separator 201 passes through the high-pressure gas pipe 402A, the heating solenoid valve 202b of the first branch 240, and the gas branch pipe 403b to the indoor unit 300b. Inflow. The refrigerant that has flowed into the indoor unit 300b is heat-exchanged with indoor air in the load-side heat exchanger 301b to be condensed and liquefied. At that time, the room where the indoor unit 300b is installed is heated. Then, the condensed and liquefied refrigerant passes through the liquid branch pipe 404b, the subcooling amount on the outlet side is controlled by the second expansion valve 211b, and becomes a liquid state of intermediate pressure between high pressure and low pressure. The refrigerant in the intermediate pressure liquid state flows into the second heat exchange unit 207 through the return intermediate pressure tube 401A.

Thereafter, the refrigerant flows into the relay bypass pipe 209 and is depressurized to a low pressure by the relay bypass flow rate adjustment valve 205, and then passes through the liquid outflow side flow rate adjustment valve 204 in the second heat exchange unit 207, that is, the relay. Heat exchanges with the refrigerant before branching to the bypass pipe 209 evaporates. Further, in the first heat exchange unit 206, the refrigerant is evaporated by exchanging heat with the refrigerant before flowing into the liquid outflow side flow rate adjustment valve 204. The evaporated refrigerant flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling electromagnetic valve 203a. Thereafter, the merged refrigerant passes through the fourth check valve 106, the flow path switching valve 102, and the accumulator 104 and is sucked into the compressor 101.

In the cooling main operation, the heating solenoid valve 202a is closed and the heating solenoid valve 202b is opened. The cooling electromagnetic valve 203a is opened, and the cooling electromagnetic valve 203b is closed. Further, since the low pressure pipe 401 is low pressure and the high pressure pipe 402 is high pressure, the refrigerant flows through the third check valve 105 and the fourth check valve 106. Further, since the second expansion valve 211a is closed, the refrigerant does not flow. Further, since the first expansion valve 210b is closed, the refrigerant does not flow.

(Heating-based operation)
FIG. 5 is a refrigerant circuit diagram illustrating a state of the air-conditioning apparatus 1 according to the embodiment of the present invention during a heating main operation.
Next, the heating main operation of the air conditioner 1 will be described with reference to FIG. In the heating main operation, the air conditioner 1 has a heating request from the indoor unit 300b and a cooling request from the indoor unit 300a.
As shown in FIG. 5, the high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102, passes through the fifth check valve 107 and the high-pressure pipe 402, and reaches the gas-liquid of the relay machine 200. The separator 201 is reached.

The refrigerant is separated into a gaseous refrigerant and a liquid refrigerant by the gas-liquid separator 201. The gaseous refrigerant that has flowed out from the gas outflow side of the gas-liquid separator 201 passes through the high-pressure gas pipe 402A and reaches the first branch 240. And a refrigerant | coolant flows in into the indoor unit 300b through the heating solenoid valve 202b of the 1st branch part 240, and the gas branch pipe 403b.

The refrigerant that has flowed into the indoor unit 300b is heat-exchanged with indoor air in the load-side heat exchanger 301b to be condensed and liquefied. At that time, the room where the indoor unit 300b is installed is heated. Then, the condensed and liquefied refrigerant is controlled by the second expansion valve 211b at the subcooling amount on the outlet side, and becomes a liquid state at an intermediate pressure between the high pressure and the low pressure. The refrigerant in the intermediate pressure liquid state passes through the liquid branch pipe 404b, the second expansion valve 211b of the second branch section 250, and the return intermediate pressure pipe 401A, and flows into the second heat exchange section 207. At this time, it flows out from the liquid outflow side of the gas-liquid separator 201 and merges with the refrigerant in the liquid state that has passed through the first heat exchange unit 206 and the liquid outflow side flow rate adjustment valve 204. The merged refrigerant branches into a refrigerant that flows into the second branch portion 250 through the high-pressure liquid pipe 402B and a refrigerant that flows into the relay bypass pipe 209.

The refrigerant that has flowed into the second branch section 250 flows into the indoor unit 300a through the first expansion valve 210a and the liquid branch pipe 404a of the second branch section 250. The refrigerant flowing into the indoor unit 300a is depressurized to a low pressure by controlling the superheat on the outlet side of the load side heat exchanger 301a by the first expansion valve 210a. The decompressed refrigerant flows into the load-side heat exchanger 301a, and is heat-exchanged with indoor air in the load-side heat exchanger 301a to be evaporated and gasified. At that time, the room in which the indoor unit 300a is installed is cooled. The refrigerant in a gas state flows into the low-pressure pipe 401 through the gas branch pipe 403a and the cooling electromagnetic valve 203a of the first branch 240.

On the other hand, the refrigerant flowing into the relay bypass pipe 209 is decompressed to a low pressure by the relay bypass flow rate adjustment valve 205 and then passed through the liquid outflow side flow rate adjustment valve 204 in the second heat exchange unit 207, that is, the relay bypass. Heat exchange with the refrigerant before branching to the pipe 209 evaporates. Further, in the first heat exchange unit 206, the refrigerant is evaporated by exchanging heat with the refrigerant before flowing into the liquid outflow side flow rate adjustment valve 204. The evaporated refrigerant flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling electromagnetic valve 203a. Thereafter, the merged refrigerant passes through the sixth check valve 108 and flows into the heat source side heat exchanger 103.

The refrigerant exchanges heat with outdoor air blown by the heat source side blower 112 in the heat source side heat exchanger 103 to evaporate and then is sucked into the compressor 101 through the flow path switching valve 102 and the accumulator 104. .

In the heating main operation, the heating solenoid valve 202b is opened, and the heating solenoid valve 202a is closed. The cooling electromagnetic valve 203a is opened, and the cooling electromagnetic valve 203b is closed. In addition, since the low pressure pipe 401 has a low pressure and the high pressure pipe 402 has a high pressure, the refrigerant flows through the fifth check valve 107 and the sixth check valve 108. Further, since the second expansion valve 211a is closed, the refrigerant does not flow. Further, since the first expansion valve 210b is closed, the refrigerant does not flow.

FIG. 6 is a flowchart showing the operation of the air-conditioning apparatus 1 according to the embodiment of the present invention when refrigerant leakage is detected.
Next, the operation | movement at the time of the refrigerant | coolant leakage detection of the air conditioning apparatus 1 is demonstrated with reference to FIG.
The leak detection unit 400 detects whether or not the refrigerant has leaked from the refrigerant circuit (step S1).
And when it is detected by the leak detection part 400 that the refrigerant | coolant leaked (Yes of step S1), the detection signal is transmitted to the control apparatus 10 (step S2).

At this time, when the air conditioner 1 is in the cooling only operation (Yes in step S3), the operation is continued with the operation mode as it is.
On the other hand, when the operation mode is other than the cooling only operation, that is, when any of the heating only operation, the cooling main operation, and the heating main operation is stopped (No in step S3), the control device 10 Is forcibly switched to the cooling only operation (step S4).

The control device 10 is in the cooling only operation, but closes all the

first expansion valves

210a and 210b and the

second expansion valves

211a and 211b (step S5). Note that the indoor unit is set so as not to be thermo-off even when the suction temperature reaches the set temperature.

Next, for example, if the leak detection unit 400 and the indoor unit or the living room can correspond to each other, that is, if the leak detection unit 400 can detect the leakage of the refrigerant for each indoor unit system or each room system, for example. (Yes in step S6), the control device 10 opens only the cooling

electromagnetic valve

203a or 203b of the system in which the refrigerant has leaked (step S7).
On the other hand, if the leak detection unit 400 and the indoor unit or the room are not compatible with each other, that is, if the leak detection unit 400 cannot detect the refrigerant leak for each indoor unit system or each room system (step S6). No), the control device 10 opens all the cooling

electromagnetic valves

203a and 203b (step S8).
In addition, even if the leak detection unit 400 and the indoor unit or the living room can respectively correspond, when it is desired to check the entire system of the air conditioner 1, all the cooling

electromagnetic valves

203a and 203b may be opened.

At this time, all the

heating solenoid valves

202a and 202b are closed for the cooling only operation.

Then, the control apparatus 10 starts the pump down driving | operation of the air conditioning apparatus 1 (step S9). The details of the pump-down operation will be described later.
The pump-down operation is performed until the recovery of the refrigerant is completed. When the recovery of the refrigerant is completed (Yes in step S10), the control device 10 stops the compressor 101 and closes all the cooling

electromagnetic valves

203a and 203b. (Step S11), the process ends.

As for the refrigerant recovery determination, for example, by attaching a liquid level determination means to the accumulator 104, it is possible to determine that the recovery is complete when a certain amount is exceeded. Or if it collects with a liquid refrigerant, since the suction side of compressor 101 will be sucked in with a gas refrigerant, suction pressure will fall. This can be detected by the suction pressure detection unit 127, and it can be determined that the recovery is completed when the pressure becomes a predetermined pressure, for example, less than 1 kg / cm ² .

(Pump down operation)
FIG. 7 is a refrigerant circuit diagram illustrating a state during the pump-down operation of the air-conditioning apparatus 1 according to the embodiment of the present invention.
Next, the pump-down operation of the air conditioner 1 will be described with reference to FIG.
As shown in FIG. 7, the high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102 and is heat-exchanged with outdoor air blown by the heat-source side blower 112 in the heat-source side heat exchanger 103. To condense. The condensed and liquefied refrigerant passes through the third check valve 105 and the high-pressure pipe 402 and reaches the gas-liquid separator 201 of the repeater 200.

The refrigerant is separated into a gaseous refrigerant and a liquid refrigerant by the gas-liquid separator 201. The liquid refrigerant that flows out from the liquid outflow side of the gas-liquid separator 201 flows in the order of the first heat exchange unit 206, the liquid outflow side flow rate adjustment valve 204, and the second heat exchange unit 207, but the first expansion valve. Since 210a, 210b and the

second expansion valves

211a, 211b are closed, the refrigerant does not flow into the

indoor units

300a, 300b.

The

heating solenoid valves

202a and 202b are closed, the cooling

solenoid valves

203a and 203b are opened, and the refrigerant present in the

indoor units

300a and 300b is cooled by the cooling

solenoid valves

203a and 203b. Therefore, the amount of refrigerant existing in the

indoor units

300a and 300b is reduced by evaporating and is eventually recovered.

Here, each indoor unit can be operated as a cooling operation to operate the indoor fan, promote evaporative gasification and agitate the indoor air with the fan, but it is necessary to operate the indoor fan. It is not something to do. Then, the refrigerant that has become a gas state in the

indoor units

300a and 300b passes through the

gas branch pipes

403a and 403b and the cooling

electromagnetic valves

203a and 203b of the first branch section 240, respectively, and then merges to pass through the low-pressure pipe 401. Pass through.

Also, a part of the refrigerant that has passed through the second heat exchange unit 207 flows into the relay bypass pipe 209. At this time, it is desirable that the liquid outflow side flow rate adjustment valve 204 and the relay bypass flow rate adjustment valve 205 have the maximum opening in the control range, and thereby flow into the relay bypass pipe 209 in a low dryness state, that is, in a state where there is a lot of liquid. Therefore, the refrigerant recovery time can be shortened.

The liquid refrigerant that has flowed into the relay bypass pipe 209 flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling

electromagnetic valves

203a and 203b. Thereafter, the merged refrigerant passes through the fourth check valve 106 and the flow path switching valve 102 and is collected in the accumulator 104. When the recovery of the refrigerant is completed, the compressor 101 is automatically stopped and all the cooling

solenoid valves

203a and 203b are closed.

As mentioned above, according to the air conditioning apparatus 1 which concerns on this Embodiment, according to the air conditioning apparatus 1 which concerns on this Embodiment, it is provided with the leak detection part 400 which detects the leakage of a refrigerant | coolant, and the control apparatus 10 is leak detection. When the refrigerant leakage is detected by the section 400, all the expansion valves that are the refrigerant inflow gates to the

indoor units

300a and 300b are closed, the pump down operation is performed, and the refrigerant is recovered to the accumulator 104 of the heat source unit 100 It is.

That is, when refrigerant leakage is detected, the indoor unit is shut off to prevent refrigerant leakage outside the indoor unit, and the refrigerant is recovered from the indoor unit to the heat source unit 100, thereby reducing the refrigerant recovery time. be able to. In addition, the indoor unit is blocked by an expansion valve to prevent refrigerant leakage outside the indoor unit, and it is not necessary to provide a new valve to prevent refrigerant leakage outside the indoor unit. Can be.

In the present embodiment, when the pump-down operation is performed, the refrigerant is recovered to the accumulator 104 of the heat source apparatus 100, but is not limited thereto, and is recovered to the compressor 101, the piping, etc. of the heat source apparatus 100. Also good.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus, 10 control apparatus, 11 memory | storage means, 12 setting means, 20 load capacity detection part, 26 heat exchange part, 100 heat source machine, 101 compressor, 102 flow path switching valve, 103 heat source side heat exchanger, 104 Accumulator, 105 third check valve, 106 fourth check valve, 107 fifth check valve, 108 sixth check valve, 112 heat source side blower, 114 main pipe, 120 heat source side heat exchange unit, 126 Discharge pressure detection unit, 127, suction pressure detection unit, 140 heat source side flow path adjustment unit, 141, first control device, 200 relay, 201, gas-liquid separator, 202a heating solenoid valve, 202b heating solenoid valve, 203a cooling Solenoid valve, 203b Cooling solenoid valve, 204 Liquid outflow side flow rate adjustment valve, 205 Relay bypass flow rate adjustment valve, 206th Heat exchange section, 207 second heat exchange section, 208 relay bypass temperature detection section, 209 relay bypass pipe, 210a first expansion valve, 210b first expansion valve, 211a second expansion valve, 211b second Expansion valve, 220, second control device, 231, first liquid outflow pressure detection unit, 232, second liquid outflow pressure detection unit, 240, first branching unit, 250, second branching unit, 300a indoor unit, 300b indoor unit, 301a Load side heat exchanger, 301b Load side heat exchanger, 303a Liquid pipe temperature detection part, 303b Liquid pipe temperature detection part, 304a Gas pipe temperature detection part, 304b Gas pipe temperature detection part, 400 Leak detection part, 401 Low pressure pipe , 401A return intermediate pressure tube, 402 high pressure tube, 402A high pressure gas tube, 402B high pressure liquid tube, 403a gas branch tube, 403b gas Tube, 404a liquid branch pipes, 404b liquid branch pipe.

Claims

A heat source machine having a compressor, a flow path switching valve, and a heat source side heat exchanger;
A plurality of indoor units having a load-side heat exchanger and performing a cooling operation or a heating operation;
A low-pressure pipe and a high-pressure pipe connecting the heat source unit and each indoor unit;
A first on-off valve that switches to connect one of the load-side heat exchangers to the low-pressure pipe; and a second switch that switches to connect the one of the load-side heat exchangers to the high-pressure pipe A first branch having an on-off valve and the other of the load-side heat exchangers are connected to a high-pressure liquid pipe via a first expansion valve and to a return intermediate pressure pipe via a second expansion valve. A relay having a second branching section,
A leak detector for detecting refrigerant leakage;
A control device for controlling the first expansion valve and the second expansion valve;
The controller is
An air conditioner that performs a pump-down operation of closing all the first expansion valves and the second expansion valves and recovering the refrigerant to the heat source unit when the leakage detection unit detects leakage of the refrigerant.
A plurality of indoor units have a cooling only operation mode in which all cooling operations are performed, and other operation modes,
The controller is
Before starting the pump down operation,
The air conditioning apparatus according to claim 1, wherein if the operation mode is other than the cooling only operation mode, the flow path switching valve is switched so as to be in a cooling only operation mode.
The controller is
The air conditioning apparatus according to claim 1 or 2, wherein when the leakage detection unit detects refrigerant leakage, all the first on-off valves are opened.
The leakage detector is provided for each indoor unit,
The controller is
The air conditioner according to claim 1 or 2, wherein when the leakage of the refrigerant is detected by the leakage detection unit, the first on-off valve corresponding to the indoor unit in which the leakage of the refrigerant is detected is opened.
The air conditioner according to any one of claims 1 to 4, wherein the heat source unit includes an accumulator.