JPH07120089A - Multi-room type air conditioner - Google Patents

Abstract

PURPOSE:To control evaporation capacity, condensation capacity in response to an operating state of an indoor unit with low-cost specifications and to obtain a high reliability of a, compressor and a stable operating state of a system in a control of an outdoor heat exchanger. CONSTITUTION:A first path of a four-way valve 3 is connected to a discharge side of a compressor 2, a second path of the valve 3 is connected to a suction side of the compressor 2, a third path of the valve 3 is connected to a gas tube 16 through a first outdoor side two-way valve 21, and one of a first outdoor side heat exchanger 4 is connected to a fourth path of the valve 3 through a second outdoor side two-way valve 22. Further, it is connected to the third path of the valve 3 through a third outdoor side two-way valve 23, and one of a second outdoor side heat exchanger 5 is connected to the fourth path of the valve 3, and connected to a gas tube 16 through a fourth outdoor side two-way valve 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner, and more particularly to control of an outdoor heat exchanger.

[0002]

2. Description of the Related Art Conventionally, as a multi-room type air conditioner of this type, for example, there is one disclosed in Japanese Patent Laid-Open No. 4-110576.

The conventional multi-room air conditioner of the above-mentioned publication will be described below with reference to the drawings.

In FIG. 5, reference numeral 1 denotes an outdoor unit of a multi-room air conditioner, which includes a compressor 2, a four-way valve 3, a first outdoor heat exchanger 4, a second outdoor heat exchanger 5, and a second outdoor heat exchanger 5. 1 outdoor side 2 way valve 6, 2nd outdoor side 2 way valve 7, 3rd outdoor side 2 way valve 4, 4th outdoor side 2 way valve 9, outdoor side expansion valve 10, discharge gas pipe 1
Made of one. An indoor unit 12 includes an indoor expansion valve 13 and an indoor heat exchanger 14.

The outdoor unit 1 and the indoor unit 12 are annularly connected by a liquid pipe 15 and a gas pipe 16 to form a refrigerant circuit 17. The first path of the four-way valve 3 is on the discharge side of the compressor 2, the second path of the four-way valve 3 is on the suction side of the compressor 2, and the four-way valve 3
Of the first and second outdoor heat exchangers 4 and 5 communicates with the fourth passage of the four-way valve 3, and the first and second outdoor heat The other one of the exchangers 4 and 5 joins via the first and second outdoor two-way valves 6 and 7, respectively, is connected to the liquid pipe 15 via the outdoor expansion valve 10, and The piping between the outdoor heat exchanger 4 and the first outdoor two-way valve 6 and the piping between the second outdoor heat exchanger 5 and the second outdoor two-way valve 7 are respectively the third and the third. 4 is connected to the discharge side of the compressor 2 via the outdoor two-way valves 6 and 7.

One of the indoor heat exchangers 14 has a gas pipe 16
The other side of the indoor heat exchanger 14 is connected to the indoor expansion valve 1
It is connected to the liquid pipe 15 via 3. It should be noted that three indoor units 12 are connected in this conventional example, and the subscripts a, b, and c are added to distinguish them.

Next, the operation of the multi-room air conditioner having the above structure will be described. First, the case of the cooling operation will be described. The flow of the refrigerant in this case is indicated by a solid arrow, the first outdoor two-way valve 6 is open, the second outdoor two-way valve 7 is open, the third outdoor two-way valve 8 is closed, and the fourth outdoor four-way valve is closed. The outdoor two-way valve 9 is closed, and each indoor expansion valve 13a, 13b, 13c has an opening degree corresponding to each indoor load. The high-temperature high-pressure gas discharged from the compressor 2 is condensed and liquefied by the first outdoor heat exchanger 4 and the second outdoor heat exchanger 5 via the four-way valve 3, and the first outdoor two-way valve. 6, passing through the second outdoor two-way valve 7, through the outdoor expansion valve 10 is decompressed by the indoor expansion valves 13a, 13b, 13c, and enters the indoor heat exchangers 14a, 14b, 14c, respectively. After evaporating and vaporizing, it returns to the compressor 2 through the four-way valve 3 to perform the cooling operation.

Next, the case of heating operation will be described. The flow of the refrigerant in this case is represented by a dashed arrow, the first outdoor two-way valve 6 is open, the second outdoor two-way valve 7 is open, the third outdoor two-way valve 8 is closed, and the fourth outdoor four-way valve is closed. The outdoor two-way valve 9 is closed, and each indoor expansion valve 13a, 13b, 13c has an opening degree corresponding to each indoor load. The high-temperature high-pressure gas discharged from the compressor 2 is passed through the four-way valve 3 to each indoor heat exchanger 14a, 14b, 14c.
To the interior of each indoor expansion valve 13a,
The pressure is reduced by the outdoor expansion valve 10 via 13b and 13c,
Passing through the first outdoor two-way valve 6 and the second outdoor two-way valve 7,
After entering the first outdoor heat exchanger 4 and the second outdoor heat exchanger 5 to evaporate and vaporize, the air is returned to the compressor 2 via the four-way valve 3 to perform the heating operation.

Next, the case of the defrosting operation will be described with reference to FIG. First, a case where only the first outdoor heat exchanger 4 is defrosted will be described. The flow of the refrigerant in this case is indicated by a solid arrow, the first outdoor two-way valve 6 is closed, the second outdoor two-way valve 7 is open, the third outdoor two-way valve 8 is open, and the fourth outdoor four-way valve is open. The outdoor two-way valve 9 is closed, and the indoor expansion valves 13a, 13b, 13c are closed.
Is an opening degree according to each indoor load. A part of the high-temperature high-pressure gas discharged from the compressor 2 is guided to the indoor heat exchangers 14a, 14b, 14c via the four-way valve 3, where it is condensed and liquefied to the indoor expansion valves 13a, 13b. , 13c, the pressure is reduced by the outdoor expansion valve 10, and the second outdoor two-way valve 7
And enters the second outdoor heat exchanger 5 and evaporates and vaporizes.
The rest of the high-temperature high-pressure gas discharged from the compressor 2 passes through the discharge gas pipe 11 and the third outdoor two-way valve 8 and is condensed in the first outdoor heat exchanger 4 (first outdoor heat The exchanger 4 is defrosted). After that, it merges with the refrigerant that has passed through the second outdoor heat exchanger 5, returns to the compressor 2 via the four-way valve 3, and performs the defrosting operation.

Next, a case where only the second outdoor heat exchanger 5 is defrosted will be described. The flow of the refrigerant in this case is indicated by a broken line arrow, the first outdoor two-way valve 6 is open, the second outdoor two-way valve 7 is closed, the third outdoor two-way valve 8 is closed, and the fourth outdoor four-way valve is closed. The outdoor two-way valve 9 is open, and each indoor expansion valve 13a, 13b, 13
c is the opening degree according to each indoor load. A part of the high-temperature high-pressure gas discharged from the compressor 2 is guided to the indoor heat exchangers 14a, 14b, 14c via the four-way valve 3, where it is condensed and liquefied to the indoor expansion valves 13a, 13b. , 13c, the pressure is reduced by the outdoor expansion valve 10, passes through the first outdoor two-way valve 6, enters the first outdoor heat exchanger 4, and is evaporated and vaporized. The rest of the high-temperature high-pressure gas discharged from the compressor 2 passes through the discharge gas pipe 11 and the fourth outdoor two-way valve 9, and is condensed in the second outdoor heat exchanger 5 (second outdoor heat). The exchanger 5 is defrosted). After that, it merges with the refrigerant that has passed through the first outdoor heat exchanger 4, and returns to the compressor 2 via the four-way valve 3,
Perform defrosting operation.

Therefore, when it is necessary to defrost the outdoor heat exchanger in this manner, the first outdoor heat exchanger 4 or the second outdoor heat exchanger 5 is alternately defrosted while performing the heating operation. It can be performed.

[0012]

However, in the above configuration, in the case of the cooling small capacity operation (for example, the indoor unit operation of 2.3 kW with respect to the outdoor unit of 29.1 kW), the minimum capacity of the compressor (5 Evaporation capacity is 2.
Since it is as small as 3 kW and the condensing capacity is as large as 14.05 kW, the condensing pressure drops extremely. In the case of heating small capacity operation (for example, indoor unit operation of 2.3 kW against outdoor unit of 29.1 kW), the condensation capacity is 2.3 kW, which is smaller than the minimum capacity of the compressor (equivalent to 5.8 kW), and evaporation capacity. Is 14.0
Since it is as large as 5 kW, the condensation pressure rises extremely. Therefore, there are problems that the reliability of the compressor is deteriorated and stable operation of the system cannot be ensured.

The present invention has been made in view of the above problems,
It is an inexpensive specification that controls the evaporation capacity and condensation capacity according to the operating status of the indoor unit to ensure the reliability of the compressor and the stable operating status of the system, and also enables heating operation during defrosting of the outdoor heat exchanger. A multi-room air conditioner is provided.

[0014]

In order to solve the above problems, the present invention provides a compressor, a four-way valve, a first outdoor heat exchanger,
Second outdoor heat exchanger, first outdoor expansion valve, second outdoor expansion valve, first outdoor two-way valve, second outdoor two-way valve, third outdoor two-way Valve, an outdoor unit including a fourth outdoor two-way valve, and a plurality of indoor units including an indoor expansion valve and an indoor heat exchanger are connected via a gas pipe and a liquid pipe, and the four-way valve One way is on the discharge side of the compressor, and the second side of the four-way valve
A passage to the suction side of the compressor, a third passage of the four-way valve to the gas pipe through the first outdoor two-way valve, and one of the first outdoor heat exchangers to the first outdoor heat exchanger. It is connected to the fourth passage of the four-way valve via the second outdoor two-way valve, and the third passage
Communicating with the third passage of the four-way valve via the outdoor two-way valve,
One of the second outdoor heat exchangers is the fourth one of the four-way valve.
The first and second outdoor heat exchangers, which communicate with the gas pipe through the fourth outdoor two-way valve, and the first and second outdoor heat exchangers, respectively. Through an outdoor expansion valve of the indoor side heat exchanger, one of the indoor side heat exchanger is connected to the gas pipe, and the other side of the indoor side heat exchanger is connected to the indoor side expansion valve. It is connected to the liquid pipe.

[0015]

In the multi-room air conditioner of the present invention, one of the outdoor heat exchangers acts as a condenser and the other outdoor heat exchanger acts as an evaporator during the cooling and heating small capacity operation by the above-mentioned configuration. It balances compression capability, evaporator capacity and condenser capacity. In addition, the heating operation can be performed during defrosting of the outdoor heat exchanger.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a multi-room air conditioner of the present invention will be described below with reference to the drawings. The same parts as those of the prior art are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 18 denotes an outdoor unit of a multi-chamber air conditioner, which includes a first outdoor expansion valve 19, a second outdoor expansion valve 20, a first outdoor two-way valve 21, and a second outdoor expansion valve 21. It has a second outdoor two-way valve 22, a third outdoor two-way valve 23, and a fourth outdoor two-way valve 24.

The first passage of the four-way valve 3 is on the discharge side of the compressor 2,
The second path of the four-way valve 3 is on the suction side of the compressor 2, the third path of the four-way valve 3 is on the gas pipe 16 via the first outdoor two-way valve 21,
One side of the first outdoor heat exchanger 4 communicates with the fourth passage of the four-way valve 3 via the second outdoor two-way valve 22 and four-way via the third outdoor two-way valve 23. One of the second outdoor heat exchangers 5 communicating with the third passage of the valve 3 is connected to the fourth passage of the four-way valve 3.
While communicating with the passage, it also communicates with the gas pipe 16 via the fourth outdoor two-way valve 24, and the other one of the first and second outdoor heat exchangers 4 and 5 is the first and the second, respectively. It is mergingly connected to the liquid pipe 15 via the second outdoor expansion valves 19 and 20.

Next, the operation in such a configuration will be described. First, the case of the cooling operation will be described.
The flow of the refrigerant in this case is indicated by a solid arrow, the four-way valve 3 is for cooling, the first outdoor two-way valve 21 is open, the second outdoor two-way valve 22 is open, and the third outdoor two-way valve. 23 is closed, the fourth outdoor two-way valve 24 is closed, each indoor expansion valve 13a, 13b, 13
c is the opening degree according to each indoor load.

The high-temperature high-pressure gas discharged from the compressor 2 is
It is condensed and liquefied by the first outdoor heat exchanger 4 and the second outdoor heat exchanger 5 via the four-way valve 3 and the second outdoor two-way valve 22, and the first outdoor expansion valve 19 2 outdoor expansion valve 20
Through the indoor expansion valves 13a, 13b, 13c, and after entering the indoor heat exchangers 14a, 14b, 14c to be vaporized and vaporized respectively, the first outdoor two-way valve 21,
Returning to the compressor 2 via the four-way valve 3, the cooling operation is performed.

Next, the case of heating operation will be described. The flow of the refrigerant in this case is indicated by a dashed arrow, the four-way valve 3 is heated, the first outdoor two-way valve 21 is open, the second outdoor two-way valve 22 is open, and the third outdoor two-way valve. 23 is closed, the fourth outdoor two-way valve 24 is closed, each indoor expansion valve 13a, 13b, 13
c is the opening degree according to each indoor load.

The high-temperature high-pressure gas discharged from the compressor 2 is
It is guided to each indoor heat exchanger 14a, 14b, 14c via the four-way valve 3 and the first outdoor two-way valve 21, where it is condensed and liquefied and then passed through each indoor expansion valve 13a, 13b, 13c. The pressure is reduced by the first outdoor expansion valve 19 and the second outdoor expansion valve 20, enters the first outdoor heat exchanger 4 and the second outdoor heat exchanger 5 and evaporates and vaporizes Outdoor two-way valve 2
2. Return to the compressor 2 via the four-way valve 3 to perform heating operation.

Next, a case where the outdoor heat exchanger is operated on one side will be described with reference to FIG. First, the case of the cooling operation will be described. Here, the operating state of each indoor unit 12 is the indoor unit 1
2a, 12b ... Stop, indoor unit 12c ... Cooling is performed, and the flow of the refrigerant in this case is indicated by solid arrows, the four-way valve 3 is cooling, the first outdoor expansion valve 19 is fully closed, and the second outdoor expansion valve is 20
Is open, the first outdoor two-way valve 21 is open, the second outdoor two-way valve 22 is closed, the third outdoor two-way valve 23 is open, and the fourth outdoor two-way valve 24 is closed. The indoor expansion valve 13c is opened according to the indoor load, and the indoor expansion valves 13a and 13b are fully closed.

The high-temperature high-pressure gas discharged from the compressor 2 is
It is condensed and liquefied in the second outdoor heat exchanger 5 via the four-way valve 3, passes through the second outdoor expansion valve 20, and passes through the indoor expansion valve 13
After depressurizing at c, the heat enters the indoor heat exchanger 14c and is vaporized, respectively, and then returns to the compressor 2 through the first outdoor two-way valve 21 and the four-way valve 3 to perform the cooling operation.

Next, the case of heating operation will be described. Here, the operating state of each indoor unit 12 is the indoor unit 12a, 12b.
... Stop, indoor unit 12c ... Heating is performed, and the flow of the refrigerant in this case is indicated by a dashed arrow, the four-way valve 3 is heated, the first outdoor expansion valve 19 is fully closed, and the second outdoor expansion valve 20 is open. , The first outdoor two-way valve 21 is open, the second outdoor two-way valve 22 is closed,
The third outdoor two-way valve 23 is open, and the fourth outdoor two-way valve 24
Is closed, the indoor expansion valve 13c is opened according to the indoor load, and the indoor expansion valves 13a and 13b are slightly opened.

The high-temperature high-pressure gas discharged from the compressor 2 is
Gas pipe 16 through four-way valve 3 and first outdoor two-way valve 21
Flow into. Part of the refrigerant flowing into the gas pipe 16 is guided to the indoor heat exchanger 14c, where it is condensed and liquefied and flows into the liquid pipe 15 via the indoor expansion valve 13c. Gas pipe 16
The rest of the refrigerant that has flowed into the indoor heat exchangers 14a, 14
It is condensed in b and flows into the liquid pipe 15 through the indoor expansion valves 13a and 13b. Then, after merging with the refrigerant that has passed through the indoor heat exchanger 14c, the pressure is reduced by the second outdoor expansion valve 20, enters the second outdoor heat exchanger 5, and is evaporated and vaporized,
The second outdoor two-way valve 22 and the four-way valve 3 are returned to the compressor 2 to perform the heating operation.

Next, the case of the defrosting operation will be described with reference to FIG. First, a case where only the second outdoor heat exchanger 5 is defrosted will be described. The flow of the refrigerant in this case is represented by a solid arrow, the four-way valve 3 is for cooling, the first outdoor two-way valve 21 is closed, the second outdoor two-way valve 22 is closed, and the third outdoor two-way valve. 23 is open, the fourth outdoor two-way valve 24 is open, and each indoor expansion valve 13a, 13b, 13c has an opening degree corresponding to each indoor load.

A part of the high-temperature high-pressure gas discharged from the compressor 2 is introduced into the indoor heat exchangers 14a, 14b, 14c via the four-way valve 3 and the fourth outdoor two-way valve 24, where Is condensed and liquefied in and flows into the liquid pipe 15 through the indoor expansion valves 13a, 13b, 13c. The rest of the high-temperature high-pressure gas discharged from the compressor 2 passes through the four-way valve 3 and is condensed in the second outdoor heat exchanger 5 (the second outdoor heat exchanger 5 is defrosted), It flows into the liquid pipe 15 via the second outdoor expansion valve 20. Then, the indoor heat exchangers 14a, 14b, 14c
The refrigerant that has passed through the first outdoor expansion valve 19 is decompressed, enters the first outdoor heat exchanger 4, and is evaporated and vaporized.
After returning to the compressor 2 via the outdoor two-way valve 23 and the four-way valve 3, the defrosting operation is performed.

Next, a case where only the first outdoor heat exchanger 4 is defrosted will be described. The flow of the refrigerant in this case is indicated by a dashed arrow, the four-way valve 3 is heating, and the first outdoor two-way valve 21 is used.
Open, the second outdoor two-way valve 22 closes, the third outdoor two-way valve 23 opens, the fourth outdoor two-way valve 24 closes, and each indoor expansion valve 13a, 13b, 13c The opening degree corresponds to each indoor load.

A part of the high-temperature high-pressure gas discharged from the compressor 2 flows into the gas pipe 16 through the four-way valve 3 and the first outdoor two-way valve 21, and the indoor side heat exchangers 14a and 14b. , 1
4c, where it is condensed and liquefied, and each indoor expansion valve 13
It flows into the liquid pipe 15 via a, 13b, and 13c.

The rest of the high-temperature high-pressure gas discharged from the compressor 2 is first passed through the four-way valve 3 and the third outdoor two-way valve 23.
Is condensed in the outdoor heat exchanger 4 of the first outdoor heat exchanger 4
Is defrosted) and flows into the liquid pipe 15 via the first outdoor expansion valve 19. Then, the indoor heat exchangers 14a, 14
b, 14c merges with the refrigerant, is decompressed by the second outdoor expansion valve 20, enters the second outdoor heat exchanger 5, evaporates and vaporizes, and returns to the compressor 2 via the four-way valve 3, Perform defrosting operation.

Therefore, when it is necessary to defrost the outdoor heat exchanger in this way, the first outdoor heat exchanger 4 or the second outdoor heat exchanger 5 is alternately defrosted while performing the heating operation. It can be performed.

Next, the case of the cooling small capacity operation will be described with reference to FIG. Here, the operating state of each indoor unit 12 is: indoor unit 12a ... cooling, indoor unit 12b, 12c ... stopped,
The flow of the refrigerant in this case is represented by a solid arrow, the four-way valve 3 is for cooling, the first outdoor two-way valve 21 is open, the second outdoor two-way valve 22 is closed, and the third outdoor two-way valve. 23 is open, the fourth outdoor two-way valve 24 is closed, the indoor expansion valve 13a is opened according to each indoor load, and the indoor expansion valves 13b and 13c are fully closed.

The high-temperature high-pressure gas discharged from the compressor 2 is
It is condensed and liquefied in the second outdoor heat exchanger 5 via the four-way valve 3, and flows into the liquid pipe 15 via the second outdoor expansion valve 20. A part of the refrigerant flowing into the liquid pipe 15 is decompressed by the indoor expansion valve 13a, enters the indoor heat exchanger 14a, evaporates and vaporizes, and then passes through the gas pipe 16 and the first outdoor two-way valve 21. Flow into the third passage of the four-way valve 3. The remaining refrigerant flowing into the liquid pipe 15 is decompressed by the first outdoor expansion valve 19,
The refrigerant that has entered the first outdoor heat exchanger 4 and has been evaporated and vaporized, then flows into the third passage of the four-way valve 3 via the third outdoor two-way valve 23, and passes through the indoor heat exchanger 14a. And then return to the compressor 2 through the four-way valve 3 to perform cooling small capacity operation.

Next, the case of the heating small capacity operation will be described. Here, the operating state of each indoor unit 12 is the indoor unit 12a ...
The heating and the indoor units 12b, 12c ... are stopped, and the flow of the refrigerant in this case is indicated by a dashed arrow. The four-way valve 3 is heated, the first outdoor two-way valve 21 is open, and the second outdoor two-way valve 22. Is closed, the third outdoor two-way valve 23 is open, the fourth outdoor two-way valve 24 is closed, the indoor expansion valve 13a is opened according to the indoor load, and the indoor expansion valves 13b and 13c are slightly opened. It is open.

A part of the high-temperature high-pressure gas discharged from the compressor 2 flows into the gas pipe 16 via the four-way valve 3 and the first outdoor two-way valve 21. A part of the refrigerant flowing into the gas pipe 16 is guided to the indoor heat exchanger 14a, condensed and liquefied therein, and then flows into the liquid pipe 15 through the indoor expansion valve 13a. The rest of the refrigerant flowing into the gas pipe 16 is the indoor heat exchanger 14
b, 14c are condensed in each indoor expansion valve 13b, 13c
Through the liquid pipe 15. And the indoor heat exchanger 1
4a merges with the refrigerant.

The rest of the high-temperature high-pressure gas discharged from the compressor 2 passes through the four-way valve 3 and the third outdoor two-way valve 23, and then the first
Is condensed in the outdoor heat exchanger 4 of the first outdoor expansion valve 19
Through the liquid pipe 15. Then, it merges with the refrigerant that has passed through the indoor heat exchangers 14a, 14b, 14c, is decompressed by the second outdoor expansion valve 20, and the second outdoor heat exchanger 5
Enters and evaporates, and returns to the compressor 2 via the four-way valve 3,
Perform small capacity heating operation.

Therefore, the cooling small capacity operation (for example, 29.1)
When the minimum capacity of the compressor is 5.8 kW when the indoor unit operation is 2.3 kW with respect to the kW outdoor unit, the capacity of the second outdoor heat exchanger 5 is increased to 5.8 kW as the first outdoor heat exchanger. By controlling the capacity of No. 4 to 3.5 kW, and at the time of heating small capacity operation (for example, indoor unit operation of 2.3 kW for outdoor unit of 29.1 kW, minimum capacity of compressor 5.8 kW), By controlling the capacity of the outdoor heat exchanger 5 of No. 2 to 5.8 kW and the capacity of the first outdoor heat exchanger 4 to 3.5 kW, the compression function power, the evaporator capacity, and the condenser capacity are balanced. It is possible to secure a stable state in a cycle.

As described above, when the outdoor heat exchanger needs to be defrosted, the first outdoor heat exchanger 4 or the second outdoor heat exchanger 5 is alternately defrosted while performing the heating operation. It can be performed. Furthermore, during cooling small capacity operation and heating small capacity operation, one of the outdoor heat exchangers is operated as a condenser and the other is operated as an evaporator, and the imbalance of compression function force, evaporator capacity, and condenser capacity, which has occurred conventionally, is unbalanced. Can be optimized, and the reliability of the compressor and the stable operating state of the system can be secured.

[0040]

As is apparent from the above description, the present invention provides a compressor, a four-way valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a first outdoor expansion valve and a first outdoor expansion valve. An outdoor unit including a second outdoor expansion valve, a first outdoor two-way valve, a second outdoor two-way valve, a third outdoor two-way valve, and a fourth outdoor two-way valve;
A plurality of indoor units including an indoor expansion valve and an indoor heat exchanger are connected via a gas pipe and a liquid pipe, and the first path of the four-way valve is on the discharge side of the compressor and the first path of the four-way valve. Two passages are on the suction side of the compressor, a third passage of the four-way valve is on the gas pipe via the first outdoor two-way valve, and one of the first outdoor heat exchangers is The second outdoor two-way valve communicates with the fourth passage of the four-way valve, and the third outdoor two-way valve communicates with the third passage of the four-way valve. One of the outdoor heat exchangers communicates with the fourth passage of the four-way valve and also communicates with the gas pipe through the fourth outdoor two-way valve, and the first and second outdoor heat exchangers are connected. The other one of the exchangers is respectively connected via the first and second outdoor expansion valves,
Connected to the liquid pipe, one of the indoor heat exchangers,
The other one of the indoor heat exchangers is connected to the liquid pipe via the indoor expansion valve in the gas pipe.

Therefore, when the outdoor heat exchanger needs to be defrosted, the first outdoor heat exchanger 4 or the second outdoor heat exchanger 5 is alternately defrosted while performing the heating operation. You can Furthermore, during cooling small capacity operation and heating small capacity operation, one of the outdoor heat exchangers is operated as a condenser and the other is operated as an evaporator, so that the compression function, the evaporator capacity, and the condenser capacity, which have been generated conventionally, can be reduced. The imbalance can be optimized, and the reliability of the compressor and the stable operating state of the system can be secured.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a multi-room air conditioner according to a first embodiment of the present invention.

FIG. 2 is a refrigeration cycle diagram showing an operating state of the outdoor heat exchanger on one side of the multi-room air conditioner of the embodiment.

FIG. 3 is a refrigeration cycle diagram showing a defrosting operation state of the multi-room air conditioner of the same embodiment.

FIG. 4 is a refrigeration cycle diagram showing a small capacity operation state of the multi-room air conditioner of the same embodiment.

FIG. 5 is a refrigeration cycle diagram of a conventional multi-room air conditioner.

FIG. 6 is a refrigeration cycle diagram showing a defrosting operation state of the conventional multi-room air conditioner.

[Explanation of symbols]

 2 Compressor 3 Four-way valve 4 First outdoor heat exchanger 5 Second outdoor heat exchanger 12 Indoor unit 13 Indoor expansion valve 14 Indoor heat exchanger 15 Liquid pipe 16 Gas pipe 18 Outdoor unit 19 1st Outdoor expansion valve 20 second outdoor expansion valve 21 first outdoor two-way valve 22 second outdoor two-way valve 23 third outdoor two-way valve 24 fourth outdoor two-way valve

Claims (1)

[Claims] 1. A compressor, a four-way valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a first outdoor expansion valve, a second
Outdoor unit including an outdoor expansion valve, a first outdoor two-way valve, a second outdoor two-way valve, a third outdoor two-way valve, and a fourth outdoor two-way valve, and an indoor expansion A plurality of indoor units consisting of a valve and an indoor heat exchanger are connected via a gas pipe and a liquid pipe, the first passage of the four-way valve is on the discharge side of the compressor, and the second passage of the four-way valve is On the suction side of the compressor, the third passage of the four-way valve is connected to the gas pipe via the first outdoor two-way valve,
One of the outdoor heat exchangers of (1) is connected to the fourth passage of the four-way valve via the second outdoor two-way valve, and the other one of the four-way valve is connected via the third outdoor two-way valve. It communicates with a 3rd path, one side of the 2nd outdoor heat exchanger communicates with the 4th way of the 4 way valve, and also connects with the gas pipe via the 4th outdoor 2 way valve. , The other one of the first and second outdoor heat exchangers is joined to the liquid pipe through the first and second outdoor expansion valves, respectively, and one of the indoor heat exchangers Is a multi-chamber air conditioner in which the gas pipe and the other one of the indoor heat exchangers are connected to the liquid pipe through the indoor expansion valve.