JP2006170541A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple constitution capable of realizing cooling/heating mixed operation, and efficiently operating an outdoor unit with high efficiency in accordance with the difference between cooling capacity and heating capacity in an air conditioner comprising a plurality of indoor units. <P>SOLUTION: In this air conditioner 1, the plurality of indoor units 6 are connected with the outdoor unit 2. The outdoor unit 2 comprises a first outdoor heat exchanger 21 and a second outdoor heat exchanger 26, a second opening and closing valve 20 is mounted in a first pipe 18 connecting the first outdoor heat exchanger 21 and a four-way valve 13, and a second bypass pipe 23 is connected between the second opening and closing valve 20 and the first outdoor heat exchanger 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner including a plurality of indoor units and capable of mixed cooling and heating operations.

As an air conditioner in which a plurality of indoor units are connected in parallel to one outdoor unit, two outdoor heat exchangers having different capacities are arranged in parallel to the compressor, and these outdoor heat exchangers are passed through. The refrigerant flow to be switched is switched by a three-way valve and a solenoid valve, and an outdoor heat exchanger that is in an operating state is selected, and the capacity control is performed by switching the air volume of the outdoor blower step by step (for example, Patent Documents) 1). Moreover, as an air conditioner with a reduced number of switching valves, the piping on the discharge side of the compressor is connected to the first port of the four-way valve, and two outdoor heat exchangers are connected in parallel to the second port. A high-pressure gas pipe connected to the outdoor unit is connected to the third port, and a pipe for collecting the refrigerant to the compressor is connected to the fourth port (for example, see Patent Document 2). When the plurality of indoor units mainly perform cooling operation (cooling-main operation), the first port and the second port are connected, and the third port and the fourth port are connected. . When a plurality of indoor units are mainly in heating operation (during heating-main operation), the first port and the third port are connected, and the second port and the fourth port are connected. . In such an air conditioner, the cost can be reduced and the size of the apparatus can be suppressed by reducing the number of switching valves.
Japanese Patent Laid-Open No. 9-60994 JP 2004-329661 A

However, the air conditioner disclosed in Patent Document 1 requires a switching valve for switching the flow path for each outdoor heat exchanger, and such a switching valve is expensive like a three-way valve or a four-way valve. Since the valve is a large valve, there is a problem that the device is expensive and large. Further, when two outdoor heat exchangers having different capacities are used, a different design is required as compared with a general multi-type air conditioner having the same capacity, which causes an increase in cost.
In the air conditioner disclosed in Patent Document 2, when performing the cooling and heating mixed operation, the outdoor unit is efficiently operated according to the difference between the output of the outdoor unit that performs the cooling operation and the output of the outdoor unit that performs the heating operation. It was hoped that.
The present invention has been made in view of such circumstances, and an object thereof is to provide a simple configuration for realizing a cooling and heating mixed operation in an air conditioner including a plurality of indoor units, The outdoor unit is operated efficiently in accordance with the difference between the cooling capacity and the heating capacity.

An invention according to claim 1 of the present invention that solves the above problems includes an outdoor unit including a compressor, a four-way valve, a first outdoor heat exchanger, a second outdoor heat exchanger, and an expansion valve, an indoor heat exchanger, And a plurality of indoor units provided with expansion valves, and a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe that connect the indoor unit and the outdoor unit via a cooling / heating switching device, The compressor is connected to the first port, and the liquid piping is connected to the second port via the expansion valve after the first and second outdoor heat exchangers are connected in parallel. The high-pressure gas pipe is connected to the third port, the fourth port is connected to the low-pressure gas pipe, and the second port and the first and second outdoor heat exchangers are connected to each other. 1 bypass pipe is connected, and this first bypass pipe is provided with a first on-off valve, The second bypass pipe is connected between the connection point of the first bypass and the first outdoor heat exchanger, and the second bypass pipe is connected to the third port. The high-pressure gas pipe is connected between a check valve provided closer to the third port than the connection point of the first bypass pipe, and the plurality of indoor units are operated mainly by cooling. While the first and second ports and the third and fourth ports are connected to each other, when operating mainly on heating, the first and third ports, and the The air conditioner is characterized in that the second and fourth ports are connected to each other.
In this air conditioner, during the cooling main operation, the second outdoor heat exchanger is operated as a condenser to generate liquid refrigerant, which corresponds to the difference between the evaporation capacity and the condensation capacity on the indoor unit side from this liquid refrigerant. Liquid refrigerant is supplied to the indoor unit, and the remainder is supplied to the first outdoor heat exchanger to be converted into gas refrigerant, which is then sucked into the compressor through the second bypass pipe. Further, during heating-main operation, a part of the gas refrigerant is supplied to the first outdoor heat exchanger through the second bypass, and the liquid refrigerant generated here is supplied to the second outdoor heat exchanger from the indoor unit. Merge with refrigerant.

The invention according to claim 2 is the air conditioner according to claim 1, wherein in the pipe connected from the second port to the first outdoor heat exchanger, the first bypass pipe is connected to the first bypass pipe. A second on-off valve is provided between the connection points of the two bypass pipes, and a third on-off valve is provided on the second bypass pipe.
In this air conditioner, during the cooling main operation or the heating main operation, the second on-off valve between the connection point of the first bypass pipe and the connection point of the second bypass pipe is closed, and the third bypass pipe is connected. Open the on-off valve and allow the refrigerant to flow through each outdoor heat exchanger in turn. During cooling operation or heating operation, the second on-off valve between the connection point of the first bypass pipe and the connection point of the second bypass pipe is opened, and the third on-off valve of the second bypass pipe is closed. Let the refrigerant flow in the same direction to each of the outdoor heat exchangers.

The invention according to claim 3 is the air conditioner according to claim 1 or claim 2, wherein the expansion valve is directly connected to the first outdoor heat exchanger, and the flow rate of the refrigerant is adjustable. In the air conditioner, which is a flow rate control valve and a second flow rate control valve that is directly connected to the second outdoor heat exchanger and capable of adjusting the flow rate of the refrigerant, The flow rate is controlled by the second flow rate control valve on the second outdoor heat exchanger side. When increasing the amount of liquid refrigerant supplied to the indoor unit, the opening of the second flow control valve is reduced.

According to a fourth aspect of the present invention, in the air conditioner according to the second aspect, when operating mainly with cooling, a difference in operating capacity between the indoor unit that performs cooling operation and the indoor unit that performs heating operation is predetermined. The first and third on-off valves are opened and the second on-off valve is closed when the capacity is equal to or less than the above capacity.
In this air conditioner, the gas refrigerant discharged from the compressor is not directly flown into the first outdoor heat exchanger because the second on-off valve is closed, so that the first bypass and the second outdoor heat are not directly flown into the first outdoor heat exchanger. Split to the exchanger. Part of the liquid refrigerant formed by heat exchange in the second outdoor heat exchanger is supplied to the indoor unit, and the rest passes through the first outdoor heat exchanger and is recovered from the second bypass pipe to the compressor. In this way, by operating the second outdoor heat exchanger as a condenser and the first outdoor heat exchanger as an evaporator, the operating capacity on the outdoor unit side is reduced according to the operating capacity difference on the indoor unit side.

According to a fifth aspect of the present invention, in the air conditioner of the second aspect, when operating mainly with heating, a difference in operating capacity between the indoor unit that performs cooling operation and the indoor unit that performs heating operation is predetermined. The first and second on-off valves are closed and the third on-off valve is opened when the capacity is equal to or less than the above capacity.
In this air conditioner, the gas refrigerant discharged from the compressor is divided into a high-pressure gas pipe and a second bypass. The gas refrigerant passing through the second bypass pipe flows into the first outdoor heat exchanger because the second on-off valve is closed. The liquid refrigerant formed by heat exchange in the first outdoor heat exchanger merges with the liquid refrigerant recovered from the indoor unit, flows into the second outdoor heat exchanger, and becomes a gas refrigerant. The gas refrigerant is recovered from the four-way valve to the compressor without flowing through the first bypass pipe because the first on-off valve is closed. In this way, by operating the first outdoor heat exchanger as a condenser and the second outdoor heat exchanger as an evaporator, the operating capacity on the outdoor unit side is reduced according to the operating capacity difference on the indoor unit side.

  According to the present invention, when a plurality of indoor units are mixed in a cooling and heating operation and the difference between the evaporation capacity and the condensation capacity on the indoor unit side is equal to or less than a predetermined capacity, one of the two outdoor heat exchangers is connected to the condenser. Since the other is operated as an evaporator, each other's ability is partially offset, and the condensation capacity of the outdoor unit as a whole, or the evaporation ability is reduced to balance with the capacity difference on the indoor unit side. It can be operated efficiently according to the operation status of the indoor unit. Further, when the flow path adjusting means is an on-off valve, the device configuration can be simplified, and the size and cost of the device can be reduced.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the air conditioner 1 according to this embodiment has one outdoor unit 2, and the outdoor unit 2 includes a high-pressure gas pipe 3, a liquid pipe 4, a low-pressure gas pipe 5, and a cooling / heating switching machine. A plurality of indoor units 6 are connected in parallel via 35 to form an indoor unit group 7.

The outdoor unit 2 includes a compressor 10, and a discharge pipe 11 of the compressor 10 is connected to a first port 13 </ b> A of a four-way valve 13 through an oil separator 12. The four-way valve 13 can switch the flow path by switching control of a control device (not shown). In FIG. 1, the first port 13A and the second port 13B are connected, and the third port 13C Although the fourth port 13D is connected, it is also possible to connect the first port 13A and the third port 13C and connect the second port 13B and the fourth port 13D.
A pipe 14 is connected to the second port 13B of the four-way valve 13, and a first bypass pipe 15 is connected in the middle of the pipe 14, and the first bypass pipe 15 is in turn, A first on-off valve 16 made of an electromagnetic valve and a check valve 17 are provided and then connected to the high-pressure gas pipe 3. The check valve 17 is set so as to prevent the backflow of the gas refrigerant from the high-pressure gas pipe 3 side. The high-pressure gas pipe 3 is a pipe disposed between the third port 13C of the four-way valve 13 and each outdoor unit 6.

  Furthermore, a first pipe 18 and a second pipe 19 are connected to the pipe 14, and in the first pipe 18, a second on-off valve 20 that functions as a flow path switching means, The 1 outdoor heat exchanger 21 and the 1st expansion valve 22 as a flow control valve are arrange | positioned in series. A second bypass pipe 23 is connected between the second on-off valve and the first outdoor heat exchanger 21, and the second on-off pipe 23 is a third on-off valve 24 serving as a flow path switching unit. Is disposed on the four-way valve 13 side of the high-pressure gas pipe 3. In addition, each on-off valve 20 and 24 can use the electromagnetic valve which can be fully closed. Further, a check valve 25 is disposed in the high-pressure gas pipe 3 between the connection point of the first bypass pipe 15 and the connection point of the second bypass pipe 23. This check valve 25 is set so as to prevent the backflow of the gas refrigerant from the indoor unit 6 side.

The second pipe 19 is joined with the first pipe 18 after a second outdoor heat exchanger 26 and a second expansion valve 27 that is a flow rate adjusting valve are arranged in series. The joined pipe 28 is connected to the liquid pipe 4 via the receiver tank 29.
Further, a pipe 30 is connected to the fourth port 13D of the four-way valve 13, and this pipe 30 joins the low-pressure gas pipe 5 and then connects to the suction pipe 32 of the compressor 10 via the accumulator 31. Has been.

  Here, the high-pressure gas pipe 3, the liquid pipe 4, and the low-pressure gas pipe 5 extending from the outdoor unit 2 toward the indoor unit group 7 are connected to the indoor units 6 after branching in the cooling / heating switching machine 35. ing. The branch pipe 3 </ b> A of the high-pressure gas pipe 3 is provided with an on / off valve 36. An open / close valve 37 is provided in the branch pipe 5 </ b> A of the low-pressure gas pipe 5. These branch pipes 3 </ b> A and branch pipes 5 </ b> A join one by one and are connected to one end side of the indoor heat exchanger 38 of the indoor unit 6. The branch pipe 4 </ b> A of the liquid pipe 4 is provided with an expansion valve 39 in the indoor unit 6 and is connected to the other end side of the indoor heat exchanger 38.

  Next, the operation of this embodiment will be described. In the air conditioner 1, a cooling operation in which all of the plurality of indoor units 6 are cooled, a heating operation in which all of the indoor units 6 are heated, and a cooling / heating mixed operation in which the cooling operation and the heating operation are mixed for each indoor unit 6. And can be implemented. In the case of the cooling and heating mixed operation, the cooling main operation or the heating main operation can be mainly performed. The cooling main operation is an operation in which the cooling operation is dominant, that is, the total value of the evaporation capacity of the indoor unit group 7 is larger than the total value of the condensation capacity. The heating main operation is an operation in which the heating operation is dominant, that is, the total value of the condensation capacity of the indoor unit group 7 is larger than the total value of the evaporation capacity.

  First, during the cooling operation, the four-way valve 13 is switched so that the first port 13A and the second port 13B are connected, the first and third on-off valves 16 and 24 are closed, and the second on-off valve 20 is opened. Further, the expansion valves 22 and 27 are set to the same predetermined opening. In the cooling / heating switching machine 35, all the on-off valves 36 are closed and all the on-off valves 37 are opened. The high-pressure gas refrigerant discharged from the compressor 10 passes through each of the two outdoor heat exchangers 21 and 26 and becomes high-pressure liquid refrigerant. After being depressurized by the expansion valves 22 and 27, the liquid refrigerant passes through the receiver tank 29. In each indoor unit 6 that is in the cooling operation through the pipe 4, the pressure is further reduced by the expansion valve 39, and then the low-pressure gas refrigerant passes through the indoor heat exchanger 38, and the interior is cooled by the evaporation heat absorbed at this time. The gas refrigerant is recovered from the low-pressure gas pipe 5 to the compressor 10 through the branch pipe 5A.

  During the heating operation, the four-way valve 13 is switched so that the first port 13A and the third port 13C are connected, the first and third on-off valves 16 and 24 are closed, and the second on-off valve 20 is opened. Further, the expansion valves 22 and 27 are set to the same predetermined opening. In the cooling / heating switching machine 35, the on-off valve 36 is opened and the on-off valve 37 is closed. The high-pressure gas refrigerant discharged from the compressor 10 passes from the high-pressure gas pipe 3 through the branch pipe 3A and becomes a liquid refrigerant in the indoor heat exchanger 38 of each indoor unit 6 that is performing heating operation. To heat the room. The liquid refrigerant is decompressed by the expansion valve 39 and then flows from the branch pipe 4 </ b> A through the liquid pipe 4 into the receiver tank 29. From here, the flow is divided into the first pipe 18 and the second pipe 19, and further decompressed by the expansion valves 22 and 27, and then converted into a low-pressure gas refrigerant by the outdoor heat exchangers 21 and 26. The valve 13 enters from the second port 13B, exits from the third port 13D, passes through the pipe 20, and is recovered by the compressor 10.

Further, the operation during the cooling main operation will be described with reference to a specific example shown in FIG. In FIG. 2, in order to distinguish each indoor unit 6, reference numerals 6A to 6D are assigned to the indoor units. Further, the case where the indoor unit 6C performs a cooling operation with an evaporation capacity of 1.0 HP (Hybrid horsepower) and the indoor unit 6D performs a heating operation with a condensation capacity of 0.7 HP is illustrated.
In the cooling / heating switching machine 35, the opening / closing valve 37 on the indoor unit 6C side and the opening / closing valve 36 on the indoor unit 6D side are opened, and the other opening / closing valves 36, 37 are all closed. In the indoor unit 6C, the liquid refrigerant is supplied from the branch pipe 4A of the liquid pipe 4, the room is cooled by heat exchange, and the low-pressure gas refrigerant is discharged to the low-pressure gas pipe 5 through the branch pipe 5A. In the indoor unit 6D, the gas refrigerant is supplied from the high-pressure gas pipe 3, the room is heated by heat exchange, and the liquid refrigerant is discharged to the liquid pipe 4 through the branch pipe 4A. As a result, liquid refrigerant equivalent to 1.0 HP is consumed in the indoor unit 6C, whereas liquid refrigerant equivalent to 0.7 HP is generated in the indoor unit 6D. Therefore, a liquid equivalent to 0.3 HP, which is a difference in capacity between the two, is generated. Insufficient refrigerant. Although the shortage of the liquid refrigerant may be supplied from the outdoor unit 2, the capacities of the first and second outdoor heat exchangers 21 and 26 are normally designed to be large, and each corresponds to, for example, 3 HP. In such a case, the capacity of any of the outdoor heat exchangers 21 and 26 is excessive. For example, when any of the outdoor heat exchangers 21 and 26 is operated as a 0.3 HP condenser, the heat balance is lost. As a result, the operating efficiency is lowered.

  Therefore, the outdoor unit 2 switches the four-way valve 13 so that the first port 13A and the second port 13B are connected. Further, the first on-off valve 16 is opened, the second on-off valve 20 is closed, and the third on-off valve 24 is opened. The high-pressure gas refrigerant from the compressor 10 is divided into the first bypass pipe 15 and the second pipe 19 and supplied to the high-pressure gas pipe 3 and the second outdoor heat exchanger 26, respectively. The high-pressure liquid refrigerant generated by the second outdoor heat exchanger 26 is divided into the liquid pipe 4 and the first outdoor heat exchanger 21, and the first outdoor heat exchanger 21 generates low-pressure gas refrigerant. . Then, the gas refrigerant is recovered from the second bypass pipe 23 to the compressor 10 through the four-way valve 13 and the pipe 30. At this time, the second expansion valve 27 is fully opened, the first expansion valve 22 is depressurized and the flow rate is controlled, and the second outdoor heat exchanger 26 is operated with a condensation capacity of 3.0 HP. The exchanger 21 is operated with an evaporation capacity of 2.7 HP. As a result, the liquid refrigerant corresponding to the capacity difference of 0.3 HP between the outdoor heat exchangers 21 and 26 remains, that is, the condensation capacity of the outdoor unit 2 as a whole becomes 0.3 HP, and the liquid supplied from the outdoor unit 3 The shortage of liquid refrigerant on the indoor units 6C and 6D side described above is satisfied by the refrigerant. The high-pressure gas refrigerant discharged from the compressor 10 passes through the first bypass pipe 15 and is supplied from the high-pressure gas pipe 3 to the outdoor unit 6D. Since the stop valve 25 is provided, the high-pressure gas refrigerant flowing through the first bypass pipe 15 and the low-pressure gas refrigerant flowing through the second bypass pipe 23 are not mixed. In such cooling-main operation, the path circulating through the compressor 10, the high-pressure gas pipe 3, the indoor units 6C and 6D, the liquid pipe 4, and the low-pressure gas pipe 5 serves as the first refrigerant circulation circuit, and both outdoor heat The path passing through the exchangers 21 and 26 is the second refrigerant circulation circuit.

Furthermore, the effect | action at the time of heating main operation | movement is demonstrated with reference to the specific example shown in FIG. FIG. 3 shows a case where the indoor unit 6A performs a cooling operation with an evaporation capacity of 0.7 HP, and the indoor unit 6B performs a heating operation with a condensation capacity of 1.0 HP.
In the cooling / heating switching machine 35, the open / close valve 37 on the indoor unit 6A side and the open / close valve 36 on the indoor unit 6B side are opened, and the other open / close valves 36 and 37 are all closed. In the indoor unit 6A, the liquid refrigerant is supplied from the branch pipe 4A of the liquid pipe 4, the room is cooled by heat exchange, and the low-pressure gas refrigerant is discharged to the low-pressure gas pipe 5 through the branch pipe 5A. In the indoor unit 6B, the gas refrigerant is supplied from the high-pressure gas pipe 3, the room is heated by heat exchange, and the liquid refrigerant is discharged to the liquid pipe 4 through the branch pipe 4A. As a result, liquid refrigerant equivalent to 0.7 HP is consumed in the indoor unit 6A, whereas liquid refrigerant equivalent to 1.0 HP is generated in the indoor unit 6B. Therefore, a liquid equivalent to 0.3 HP, which is a difference in capacity between the two, is generated. The refrigerant becomes excessive. The excess of the liquid refrigerant may be recovered by the outdoor unit 2. However, as described above, for example, if one of the outdoor heat exchangers 21 and 26 is operated as a 0.3 HP evaporator, the heat balance is lost. As a result, the operating efficiency is lowered.

  For this reason, the outdoor unit 2 switches the four-way valve 13 so that the first port 13A and the third port 13C are connected. Further, the first on-off valve 16 and the second on-off valve 20 are closed, the third on-off valve 24 is opened, and the high-pressure gas refrigerant from the compressor 10 is supplied to the high-pressure gas pipe 3 and the second bypass pipe 23. To divert. The gas refrigerant flowing through the second bypass pipe 23 becomes a liquid refrigerant in the first outdoor heat exchanger 21. This liquid refrigerant merges with the liquid refrigerant recovered from the liquid pipe 4, is supplied to the second outdoor heat exchanger 26, becomes a low-pressure gas refrigerant, passes through the pipe 14, the four-way valve 13, and the pipe 30. It is recovered by the compressor 10. At this time, the first expansion valve 22 is fully opened, the second expansion valve 27 is depressurized and the flow rate is controlled, and the first outdoor heat exchanger is operated with a condensation capacity of 2.7 HP, while the second outdoor heat exchange is performed. When the chamber 26 is operated at an evaporation capacity of 3.0 HP, the total evaporation capacity of the outdoor unit 2 becomes 0.3 HP, and it becomes possible to evaporate excess liquid refrigerant generated in the indoor units 6A and 6B. In such a heating-main operation, a path that circulates the compressor 10, the high-pressure gas pipe 3, the indoor units 6A and 6B, the liquid pipe 4, and the low-pressure gas pipe 5 serves as a first refrigerant circulation circuit, and both outdoor heat The path passing through the exchangers 21 and 26 is the second refrigerant circulation circuit.

  In this embodiment, it has the 1st, 2nd outdoor exchangers 21 and 26 connected in parallel at the time of cooling operation or heating operation, and it is constituted so that the circulation direction of the refrigerant may be switched by the four-way valve 13, The third port 13C and the first outdoor heat exchanger 21 can be connected by the second bypass pipe 23, and the gas refrigerant from the compressor 10 is sequentially passed through the outdoor heat exchangers 21 and 26. . Therefore, one of the outdoor heat exchangers 21 and 26 can be used as a condenser, and the other can be used as an evaporator, so that a part of the capacity of the outdoor heat exchangers 21 and 26 can be offset and the total heat The exchange capacity can be reduced. As a result, during the cooling and heating mixed operation, the balance between the indoor unit 6 side and the outdoor unit 2 side is maintained even when the difference between the evaporation capacity (cooling capacity) and the condensation capacity (heating capacity) on the indoor unit 6 side is equal to or less than a predetermined capacity. be able to. At this time, the second on-off valve 20 is provided between the first outdoor heat exchanger 21 and the second port 13B of the four-way valve 13, and the third on-off valve 24 is provided in the second bypass pipe 23. The flow path can be switched only by the opening / closing operation. Further, since the first and second expansion valves 22 and 27 are provided for each of the outdoor heat exchangers 21 and 26, in addition to the refrigerant pressure control, the amount of refrigerant supplied to the outdoor heat exchangers 21 and 26 It is possible to control the capacity of the heat exchanger. In addition, it is possible to switch between the cooling operation, the heating operation, the cooling main operation, and the heating main operation by one four-way valve 13 and three on-off valves 16, 20, and 24. Miniaturization and cost reduction can be achieved.

The present invention is not limited to the above-described embodiment, and can be applied without departing from the spirit of the present invention.
For example, only the first on-off valve 16 may be provided without providing the check valve 17.
The same operation and effect can be obtained by providing an expansion valve as a flow rate adjusting valve instead of the first on-off valve 16 and providing one expansion valve in the pipe 28 instead of the expansion valves 22 and 27. can get. The flow path switching means may be a three-way valve provided at a connection point between the first pipe 18 and the second bypass pipe 23.

It is a figure which shows the system configuration | structure of the air conditioner which concerns on embodiment of this invention. It is a figure explaining the flow of the refrigerant at the time of cooling main operation. It is a figure explaining the flow of the refrigerant at the time of heating main operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Outdoor unit 3 High pressure gas piping 4 Liquid piping 5 Low pressure gas piping 6, 6A, 6B, 6C, 6D Indoor unit 10 Compressor 13 Four-way valve (switching valve)
13A 1st port 13B 2nd port 13C 3rd port 13D 4th port 14 Piping 15 1st bypass piping 20 2nd on-off valve 21 1st outdoor heat exchanger 22 1st expansion valve 23 2nd bypass piping 24 3rd on-off valve 26 2nd outdoor heat exchanger 27 2nd expansion valve

Claims (5)

A compressor, a four-way valve, a first outdoor heat exchanger, a second outdoor heat exchanger, an outdoor unit provided with an expansion valve, an indoor heat exchanger, a plurality of indoor units provided with an expansion valve, the indoor unit and the A high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe that connect the outdoor unit via a cooling / heating switching device;
In the four-way valve, the first port is connected to the compressor, and the second port is connected to the first and second outdoor heat exchangers in parallel, and then the liquid is passed through the expansion valve. A pipe, a third port connected to the high-pressure gas pipe, a fourth port connected to the low-pressure gas pipe, the second port, the first and second outdoor heat exchangers, A first bypass pipe is connected between the first bypass pipe and the first on-off valve. The first bypass pipe is connected to the high-pressure gas pipe. The first bypass connection point and the first outdoor heat are connected to the first bypass pipe. A second bypass pipe is connected to the exchanger, and the second bypass pipe is provided closer to the third port than a connection point between the third port and the first bypass pipe of the high-pressure gas pipe. Connected to a non-return valve When the indoor unit is operated mainly as a cooling unit as a whole, the first and second ports are connected to each other, and the third and fourth ports are connected to each other. An air conditioner characterized in that the first and third ports are connected to the second and fourth ports, respectively.   In a pipe connected from the second port to the first outdoor heat exchanger, a second on-off valve is provided between a connection point of the first bypass pipe and a connection point of the second bypass pipe, and the first The air conditioner according to claim 1, wherein a third on-off valve is provided in the 2-bypass pipe.   The expansion valve is directly connected to the first outdoor heat exchanger and is directly connected to the first flow control valve capable of adjusting the flow rate of the refrigerant and the second outdoor heat exchanger, and adjusts the flow rate of the refrigerant. The air conditioner according to claim 1 or 2, wherein the air conditioner is a possible second flow control valve.   When operating mainly with cooling, when the operating capacity difference between the indoor unit that performs cooling operation and the indoor unit that performs heating operation is equal to or less than a predetermined capacity, the first and third on-off valves are opened, The air conditioner according to claim 2, wherein the second on-off valve is closed. When an operation capacity difference between the indoor unit performing the cooling operation and the indoor unit performing the heating operation is equal to or less than a predetermined capacity when operating mainly with heating, the first and second on-off valves are closed, The air conditioner according to claim 2, wherein the third on-off valve is opened.

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