KR20050002962A - Multi-chamber type air conditioner and control method thereof - Google Patents

Abstract

PURPOSE: A multi-room air conditioner and a method for controlling the same are provided to improve the cooling performance of a cooling indoor unit by supplying an appropriate amount of a refrigerant to the cooling indoor unit even if an outdoor temperature exchanges or a pipe between an outdoor unit and an indoor unit becomes long. CONSTITUTION: An outdoor unit(100) includes compressors(103a,103b), a four-way valve(104), an outdoor electromotive expansion valve(102), and outdoor heat exchangers(101a,101b). A plurality of indoor units(200a,200b,200c,200d) include indoor electromotive expansion valves(202a,202b,202c,202d) and indoor heat exchangers(201a,201b,201c,201d) respectively. Valves(301a,301b,301c,301d, 302a,302b,302c,302d) for converting a refrigerant flow convert flow direction of a refrigerant from the compressors to each indoor heat exchanger or from each indoor heat exchanger to the compressors. An electromotive expansion valve(303) is installed at an exit of the indoor heat exchanger acting as an evaporator for controlling an amount of the refrigerant flowed into the indoor heat exchanger acting as a condenser and the compressors from the indoor heat exchanger acting as an evaporator. An outdoor air temperature sensor(108) detects a temperature of outdoor air of the outdoor unit. A control device controls openness of the electromotive expansion valve for controlling an amount of the refrigerant flowed into the cooling indoor unit from the heating indoor unit in simultaneous cooling and heating operations according to an output value of the outdoor temperature sensor.

Description

Multi-chamber type air conditioner and control method

The present invention relates to a multi-chamber air conditioner, and more particularly, to a multi-chamber air conditioner including one or more outdoor units and two or more indoor units and simultaneously performing heating and cooling operations in indoor units.

Japanese Patent Laid-Open No. Hei 6-317360 discloses a multi-room air conditioner that performs simultaneous heating and cooling operations in indoor units.

As shown in FIG. 1, the multi-room air conditioner includes an outdoor unit 1 including a variable capacity compressor 2, a four-way valve 3, an outdoor side expansion valve 5, and an outdoor side heat exchanger 4. ), A first chamber 6a including an indoor electric expansion valve 7a and an indoor heat exchanger 8a, and an indoor electric heat expansion valve 7b and an indoor heat exchanger 8b. The first branch unit 20a including the two chambers 6b, the discharge side solenoid valve 21a and the suction side solenoid valve 21b, and the discharge side solenoid valve 22a and the suction side solenoid valve 22b. It includes a second branch unit 20b provided.

Referring to the operation of FIG. 1, when the first chamber is heated and the second chamber is cooled, the high-pressure refrigerant for heating discharged from the compressor 2 is heated through the high-pressure gas pipe 21a. It passes through and flows into the liquid pipe 9 through the indoor-side electric expansion valve 7a. This liquid refrigerant branches from the A portion, partly flows into the cooling indoor side heat exchanger 8b, and the rest flows into the outdoor side heat exchanger 4. In the part A, the outdoor side electric expansion valve 5 is controlled in accordance with the pressure of the liquid pipe in order to supply an appropriate amount of liquid refrigerant to the cooling indoor side heat exchanger 8b.

In the conventional multi-chamber air conditioner of FIG. 1, when the piping distance between the outdoor unit 1 and the indoor units 8a and 8b is increased, the amount of the refrigerant which is stagnated in the liquid pipe increases, so that the amount of the refrigerant flowing into the cooling indoor unit 8b is relatively increased. This decreases. In addition, if the outdoor air temperature of the outdoor unit is relatively low, the pressure on the outdoor side is lowered, so that the amount of the refrigerant flowing into the cooling chamber 8b is reduced because the refrigerant flows to the outdoor side. As such, when the amount of the refrigerant flowing into the cooling chamber does not reach an appropriate amount, the performance of the cooling chamber is deteriorated.

In addition, in FIG. 1, the outdoor side electric expansion valve 4 is controlled in order to introduce an appropriate amount of the liquid refrigerant passing through the heating indoor unit 8a into the cooling indoor unit 8b. However, by using the outdoor motor expansion valve 4, it is necessary to adjust the opening degree of the outdoor motor expansion valve in consideration of the superheat degree control of the outdoor heat exchanger acting as an evaporator, thereby constantly supplying a proper amount of refrigerant to the cooling chamber. There is a problem that is difficult to do.

The present invention is to solve the above-mentioned problems, an object of the present invention is to supply a refrigerant in a sufficient amount of the cooling room when the indoor units are air-conditioned at the same time in the main heating operation, multi-chamber air for improving the cooling capacity of the cooling room It is to provide a conditioner and a control method thereof.

1 is a control block diagram of a conventional multi-chamber air conditioner.

2 is a control block diagram of a multi-chamber air conditioner according to an embodiment of the present invention.

3 is a control flowchart of a control method of a multi-chamber air conditioner during simultaneous heating and cooling operations in FIG. 2.

4 is a graph showing the cooling performance of the cooling chamber which is changed by adjusting the opening degree of the air-conditioning switching side electric expansion valve at a specific indoor and outdoor temperature.

5 is a graph showing the cooling performance of the cooling chamber which is changed by adjusting the opening degree of the air-conditioning switching side electric expansion valve at different indoor and outdoor temperatures.

* Description of the symbols for the main functions of the drawings *

100: outdoor unit 108: outdoor temperature sensor

200a ~ 200d: Indoor unit 201a ~ 201d: Indoor side heat exchanger

202a ~ 202d: Indoor electric expansion valve 203a: Outlet temperature sensor

204a: inlet temperature sensor 300: air conditioning switch

303: air-conditioning switching side electric expansion valve 303 ': valve for adjusting flow rate

The multi-chamber air conditioner of the present invention for achieving the above object has a plurality of outdoor units having a compressor, a four-way valve, an outdoor electric expansion valve, an outdoor heat exchanger, and a plurality of indoor air expansion valves and an indoor heat exchanger. An indoor unit and a refrigerant flow direction switching valve for switching the flow direction of the refrigerant from the compressor to each indoor side heat exchanger or each indoor side heat exchanger to the compressor, and an evaporator installed at the outlet side of the indoor heat exchanger acting as an evaporator. It includes an air-conditioning switching device having an electric expansion valve for controlling the amount of refrigerant flowing into the indoor heat exchanger and the compressor in the indoor heat exchanger acting as a condenser.

The air-conditioning switching side electric expansion valve is installed on a common pipe to which the outlet refrigerant pipes of the indoor heat exchangers acting as the evaporator are connected.

The air-conditioning switching device is characterized in that it further comprises a flow rate adjustment valve connected in parallel with the air-conditioning switching side electric expansion valve.

In addition, the multi-chamber air conditioner according to the present invention includes an outdoor unit having a compressor, a four-way valve, an outdoor electric expansion valve, an outdoor heat exchanger, a plurality of indoor units having an indoor electric expansion valve and an indoor heat exchanger, and a refrigerant. Refrigerant flow direction switching valve for changing the flow direction from the compressor to each indoor side heat exchanger or each indoor side heat exchanger to the compressor, the indoor side installed at the outlet side of the indoor heat exchanger acting as an evaporator to act as an evaporator An air-conditioning switching device having an indoor heat exchanger acting as a condenser in the heat exchanger and an electric expansion valve for controlling the amount of refrigerant flowing into the compressor, an outdoor air temperature sensor for detecting the outdoor air temperature of the outdoor unit, and heating during simultaneous heating and cooling operation. The cooling according to the output value of the outdoor temperature sensor to adjust the amount of refrigerant flowing from the indoor unit to the cooling chamber. And a control device for controlling the opening degree of the heating switching side electric expansion valve.

The control device is characterized in that for controlling the opening degree of the air-conditioning switching side electric expansion valve within 15% to 25% of the total opening.

The control device is characterized in that the lower the outdoor temperature, the more the opening degree of the air-conditioning switching side electric expansion valve is closed to increase the amount of refrigerant flowing from the heating chamber to the cooling chamber.

The air-conditioning switching device further includes a flow rate adjustment valve connected in parallel with the air-conditioning switching side electric expansion valve, the control device is characterized in that for closing the flow rate adjustment valve during the heating and cooling operation.

The indoor unit further includes an inlet and outlet temperature sensor for detecting the inlet and outlet piping temperature of the indoor side heat exchanger, and the control device controls the opening degree of the electric expansion valve according to the degree of superheat according to the output value of the inlet and outlet temperature sensor of the cooling chamber. It is characterized by further adjusting.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 is a control block diagram of a multi-chamber air conditioner according to an embodiment of the present invention. As shown in FIG. 2, the multi-chamber air conditioner according to the embodiment of the present invention includes one outdoor unit 100, four indoor units 200a, 200b, 200c, and 200d, an outdoor unit 100, and each indoor unit 200a, It comprises a cooling and heating switching unit 300 is installed on the hydraulic line between 200b, 200c, 200d.

The outdoor unit 100 includes an outdoor side heat exchanger (101a, 101b), an outdoor side electric expansion valve (102), two variable displacement compressors (103a, 103b), a four-way valve (104), an oil separator (105), and a receiver ( 106, the accumulator 107, and an outdoor temperature sensor 108 for detecting the outside air temperature of the outdoor unit.

Each indoor unit (200a, 200b, 200c, 200d) is configured to adjust the inlet and outlet piping temperatures of the indoor heat exchanger (201a, 201b, 201c, 201d), the electric expansion valve (202a, 202b, 202c, 202d) and the indoor heat exchanger. Inlet temperature sensors 203a, 203b, 203c, and 203d and outlet temperature sensors 204a, 204b, 204c and 204d for detecting are included.

Air-conditioning switching unit 300 is a high-pressure gas valve (301a, 301b, 301c, 301d) installed in the high pressure gas pipe (HPP) between the outdoor unit 100 and each indoor unit (200a, 200b, 200c, 200d), low pressure gas pipe (LPP) Low pressure gas valve (302a, 302b, 302c, 302d) respectively installed on the), the electric expansion valve 303 is installed on the common hydraulic line discharged to the outdoor unit 100 side from each indoor unit (200a, 200b, 200c, 200d) ). At this time, the high pressure gas valve (301a, 301b, 301c, 301d) and the low pressure gas valve (302a, 302b, 302c, 302d) is a flow direction of the refrigerant from the compressor to each indoor heat exchanger or each indoor heat exchanger to the compressor Refrigerant flow direction switching valve for switching.

One end of the four-way valve of the outdoor unit 100 and the high pressure gas valves 301a, 301b, 301c, and 301d of the air conditioning switch 300 are connected through the high pressure gas pipe HPP. In addition, the accumulator 107 of the outdoor unit 100 and the low pressure gas valves 302a, 302b, 302c and 302d of the air conditioner 300 are connected through a low pressure gas pipe LLP.

Meanwhile, a return pipe RP is installed between the outdoor side heat exchangers 101a and 101b of the outdoor unit 100 and the air conditioning unit 300, and the outdoor side electric expansion valve 102 is provided in the return pipe RP. Is installed. The flow rate adjusting valve 102 'is connected in parallel to the motor expansion valve 102.

The return pipe RP and the outlet pipes EP1, EP2, EP3, and EP4 of each of the indoor side heat exchangers 201a, 201b, 201c, and 201d are connected to each other, and the air conditioner 300 Motor expansion valve 303 is disposed. Therefore, instead of the outdoor side expansion valve 102, the separate air-conditioning switching is performed at the point where the refrigerant heat exchanged in each indoor side heat exchanger 201a, 201b, 201c, 201d of the indoor units 200a, 200b, 200c, 200d joins. By providing the side motor expansion valve 303, it is possible to prevent a phenomenon in which the refrigerant is stagnated in the liquid pipe when the return pipe resulting from the conventional method of controlling the outdoor motor expansion valve is lengthened.

In addition, a flow rate adjusting valve 303 'is connected in parallel to the motor expansion valve 303. By adjusting the electric expansion valve 303 and the flow control valve 303 ', the amount of refrigerant flowing into the outdoor heat exchanger 101 side and the indoor heat exchanger 201a side of the cooling chamber 200a is adjusted.

The compressors 103a and 103b, the four-way valve 104, the outdoor expansion valve 102, the air-conditioning switching side expansion valve 303, the flow control valve 303 ', high pressure gas valves 301a , 301b, 301c, 301d, low pressure gas valves 302a, 302b, 302c, 302d, etc., are driven by an outdoor controller (not shown), and indoor side expansion valves 202a, 202b, 202c, 202d are not shown. It is driven by each indoor controller shown.

Hereinafter, the process of simultaneous heating and cooling in the main heating operation will be described.

Referring to the operation of FIG. 2 when one indoor unit 200a is air-cooled in FIG. 2 and the other three indoor units 200b, 200c, and 200d are heated and operated simultaneously, first, all the low-pressure gas valves 302a, 302b, 302c and 302d are closed, the high pressure gas valve 301a on the cooling chamber side is closed, and the high pressure gas valves 301b, 301c and 301d on the heating chamber side are opened.

The high temperature and high pressure refrigerant gas compressed by the compressors 103a and 103b is passed to the indoor heat exchangers 201b, 201c and 201d which operate as a condenser through the high pressure gas pipe (HPP) and the high pressure gas valves 301b, 301c and 301d. Inflow and heat exchange. The refrigerant heat-exchanged in the indoor heat exchangers 201b, 201c, and 201d reaches the electric expansion valve 303 via the outlet pipes EP2, EP3, EP4 of the indoor heat exchangers. At this time, if the opening degree of the cooling / heating switching side electric expansion valve 303 is adjusted, the amount of refrigerant flowing into the outdoor heat exchanger (101a, 101b) side or the indoor heat exchanger (201a) side of the cooling chamber can be adjusted.

That is, when the flow rate adjusting valve 303 'of the air conditioning and switching device is closed and the opening degree of the electric expansion valve 303 is adjusted, heat exchange is performed in the indoor side heat exchangers 201b, 201c, and 20d of the heating chambers 200b, 200c, and 200d. The refrigerant flows into the outdoor heat exchanger (101a, 101b) and the appropriate amount of refrigerant flows into the indoor heat exchanger (201a) of the cooling chamber (200a) that operates as an evaporator through the outlet pipe (EP1) to exchange heat. The heat exchanged refrigerant is circulated to the accumulator 107 via a low pressure gas pipe (LPP). Accordingly, one indoor unit is cooled and the other three indoor units are heated.

Hereinafter, a method of controlling the opening degree of the air-conditioning switching side electric expansion valve during the simultaneous heating and cooling operation in the main heating operation in which one indoor unit is heated and the remaining three indoor units are heated.

3 is a control flowchart of a control method of a multi-chamber air conditioner during simultaneous heating and cooling operations in FIG. 2. As shown in FIG. 3, the outdoor air temperature is read through the outdoor temperature sensor 108 of the outdoor unit 100 (100).

After reading the outdoor air temperature, the opening degree of the air-conditioning switching side electric expansion valve 303 is adjusted according to the outdoor air temperature read. In more detail, first, it is determined whether the outdoor air temperature is lower than a preset temperature (110).

After comparing the outdoor air temperature and the preset temperature, the temperature difference between the outdoor air temperature and the preset temperature is calculated, and then the degree to which the electric expansion valve 303 is opened or closed is adjusted according to the calculated temperature difference. In general, when the outdoor air temperature is low, the amount of refrigerant flowing into the outdoor heat exchanger (101a, 101b) increases, while the amount of refrigerant flowing into the indoor heat exchanger of the cooling chamber is less than an appropriate amount. The cooling capacity of is lowered. Therefore, in this case, the control of closing the opening degree of the electric expansion valve 303 is performed to reduce the amount of refrigerant flowing into the outdoor heat exchanger side, and instead, the amount of refrigerant flowing into the indoor heat exchanger of the cooling chamber is increased (120). ).

On the other hand, when the outdoor air temperature is high, the amount of refrigerant flowing into the outdoor heat exchanger (101a, 101b) decreases, while the amount of refrigerant flowing into the indoor heat exchanger (201a) of the cooling chamber (200a) is excessively greater than the proper amount. It flows in and the cooling capacity of a cooling chamber deteriorates. Therefore, in this case, the control of opening the opening degree of the electric expansion valve 303 is performed to increase the amount of refrigerant flowing into the outdoor heat exchangers 101a and 101b, and instead, the indoor heat exchanger of the cooling chamber 200a ( Reduce the amount of refrigerant flowing into the 201a) (130).

At this time, the opening degree of the air-conditioning switching side expansion valve 303 is represented by the output step. For example, the total step is in the range of 2001 steps (control step is 0 to 2000), and the output step is 0 to completely close the opening degree of the valve. In this state, the output step 2000 is in a state where the valve opening degree is completely opened. In the embodiment of the present invention, the opening degree of the air-conditioning switching side electric expansion valve 3030 is controlled within the range of 15% to 25% of the total opening degree, that is, 300 to 500 steps according to the outdoor air temperature.

The inlet piping temperature is measured through the inlet and outlet temperature sensors 204a and 203a which detect the inlet and outlet piping temperatures of the indoor heat exchanger 201a of the air conditioner 200a after first adjusting the air-conditioning switching side electric expansion valve 303. Read the outlet piping temperature with (140).

The opening degree of the air-conditioning switching side electric expansion valve 303 is adjusted in accordance with the read inlet pipe temperature and outlet pipe temperature. In more detail, the temperature difference between the inlet pipe temperature and the outlet pipe temperature read first, that is, the superheat (inlet pipe temperature-outlet pipe temperature) is calculated (150).

After the degree of superheat is calculated, the opening degree of the heating / cooling switching side electric expansion valve 303 is secondarily adjusted according to the calculated degree of superheat. That is, it is determined whether the superheat degree calculated in the operation mode 150 satisfies the preset superheat degree in the normal state (160). If the superheat degree calculated as a result of the determination in the operation mode 160 is equal to the preset superheat degree, the amount of refrigerant flowing into the indoor heat exchanger 201a of the cooling chamber 200a is appropriate, and thus the current of the heating / cooling switching side electric expansion valve 303 A control to maintain the opening degree is performed to maintain the amount of refrigerant flowing into the indoor heat exchanger 201a of the cooling chamber 200a (170).

On the other hand, when the superheat degree calculated as a result of the determination in the operation mode 160 is greater than the preset superheat degree, since the refrigerant is excessively introduced into the indoor heat exchanger 201a of the cooling chamber 200a, the air conditioning switching side electric expansion valve 303 The amount of refrigerant flowing into the indoor heat exchanger 201a of the cooling chamber 200a is reduced by performing a control to open the opening degree of the cooling chamber 200a.

In addition, if the superheat degree calculated as a result of the determination in the operation mode 160 is less than the preset superheat degree, the refrigerant flowing into the indoor heat exchanger 201a of the cooling chamber 200a is insufficient, so the heating / cooling switching side electric expansion valve 303 The amount of refrigerant flowing into the indoor heat exchanger 201a of the cooling chamber 200a is increased by performing control to close the opening degree of the cooling chamber 200a (190).

As described above, in the embodiment of the present invention, the opening degree of the air-conditioning switching side electric expansion valve is controlled within the range of 15% to 25% of the total opening degree according to the outdoor temperature. In this case, as shown in FIGS. 4 and 5, respectively. Indoor air temperature 21 ℃ (Excluding humidity) / 17 ℃ (Humidity) and outdoor air temperature -5 ℃, Indoor air temperature 27 ℃ (Humidity excluding temperature) / 19 ℃ (Humidity) and outdoor air temperature Experimenting at -5 ℃ can be seen that the cooling performance of the cooling chamber improves up to about 116%. On the contrary, when the opening degree of the conventional outdoor electric expansion valve is adjusted, the cooling performance of the cooling chamber is only 14% to 40% under the same conditions. In addition, in the conventional method, even if the outdoor temperature is increased, the cooling performance of the cooling chamber is only about 77% at maximum. Therefore, in the embodiment of the present invention, if the opening degree of the air-conditioning switching side electric expansion valve 303 is controlled within the range of 15% to 25% of the total opening degree, that is, 300 to 500 steps, the cooling performance of the cooling chamber is significantly improved compared to the conventional one. There is an advantage.

As described in detail above, the present invention adjusts the amount of refrigerant flowing into the indoor heat exchanger of the cooling chamber from the indoor heat exchanger of the heating chamber on the common hydraulic line where the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger. By installing an electric expansion valve to control the air conditioner and adjusting the opening degree of the electric expansion valve according to the outdoor air temperature during simultaneous operation of air conditioning and heating, it is possible to supply a proper amount of refrigerant to the cooling room even if the outdoor temperature changes or the piping length between the outdoor unit and the indoor unit becomes long. Therefore, the cooling performance of the cooling chamber can be improved, so that the optimum heat recovery operation can be performed.

Claims (16)

An outdoor unit having a compressor, a four-way valve, an outdoor expansion valve, and an outdoor heat exchanger; A plurality of indoor units having an indoor expansion valve and an indoor heat exchanger; A refrigerant flow direction switching valve for switching the flow direction of the refrigerant from the compressor to each indoor side heat exchanger or each indoor side heat exchanger to the compressor, and installed at the outlet side of the indoor heat exchanger acting as an evaporator to act as an evaporator. A multi-chamber air conditioner including an air conditioner and a heat exchanger having an electric expansion valve for controlling the amount of refrigerant flowing into the compressor and the indoor heat exchanger acting as a condenser in the indoor heat exchanger. The multi-chamber air conditioner according to claim 1, wherein the air-conditioning switching side electric expansion valve is installed in a common pipe to which outlet refrigerant pipes of the indoor heat exchangers acting as the evaporator are connected. The multi-chamber air conditioner according to claim 1 or 2, wherein the air-conditioning switching device further includes a flow rate adjusting valve connected in parallel with the air-conditioning switching-side electric expansion valve. An outdoor unit having a compressor, a four-way valve, an outdoor expansion valve, and an outdoor heat exchanger; A plurality of indoor units having an indoor expansion valve and an indoor heat exchanger; A refrigerant flow direction switching valve for switching the flow direction of the refrigerant from the compressor to each indoor side heat exchanger or each indoor side heat exchanger to the compressor, and installed at the outlet side of the indoor heat exchanger acting as an evaporator to act as an evaporator. An air-conditioning and switching device including an electric expansion valve for controlling the amount of refrigerant flowing into the indoor heat exchanger and the compressor that acts as a condenser in the indoor heat exchanger; An outdoor air temperature sensor detecting an outdoor air temperature of the outdoor unit; A multi-chamber air conditioner including a control unit for controlling the opening degree of the air-conditioning switching side electric expansion valve according to the output value of the outdoor temperature sensor to adjust the amount of refrigerant flowing from the heating chamber to the cooling chamber during simultaneous heating and cooling. The multi-chamber air conditioner according to claim 4, wherein the control device adjusts the opening degree of the air-conditioning switching side electric expansion valve within 15% to 25% of the total opening degree. The method according to claim 4 or 5, wherein the control device is characterized in that the lower the outdoor temperature, the more the opening degree of the air-conditioning switching side electric expansion valve is closed to increase the amount of refrigerant flowing from the heating chamber to the cooling chamber. Multi-room air conditioner. The air conditioner according to claim 4, wherein the air-conditioning switching device further includes a flow rate adjusting valve connected in parallel with the air-conditioning switching side electric expansion valve, and the control device closes the flow rate adjusting valve during the simultaneous heating and cooling operation. Multi-room air conditioner. According to claim 4 or 5, wherein the indoor unit further comprises an inlet and outlet temperature sensor for detecting the inlet and outlet pipe temperature of the indoor heat exchanger, the control device is a superheat degree according to the output value of the inlet and outlet temperature sensor of the cooling chamber Multi-room air conditioner, characterized in that for further adjusting the opening degree of the electric expansion valve. An outdoor unit having a compressor, a four-way valve, an outdoor electric expansion valve, and an outdoor heat exchanger, a plurality of indoor units having an indoor electric expansion valve and an indoor heat exchanger, and the flow direction of the refrigerant in the indoor heat exchanger in the compressor. Or a refrigerant flow direction switching valve for converting each indoor side heat exchanger into a compressor and an indoor side heat exchanger installed at an outlet side of an indoor heat exchanger acting as an evaporator and acting as a condenser in an indoor heat exchanger acting as an evaporator. Cooling and heating switching device having an electric expansion valve for controlling the amount of refrigerant flowing into the air compressor and the compressor, and the control unit for controlling the compressor, the four-way valve, the refrigerant flow direction switching valve and the electric expansion valves and simultaneously heating and cooling the indoor units In the control method of the multi-room air conditioner to operate, When the air conditioning and heating at the same time read the outdoor air temperature through the outdoor temperature sensor, And controlling the opening degree of the air-conditioning switching-side electric expansion valve according to the temperature difference by comparing the read-out outdoor air temperature with a preset temperature. The control method of a multi-chamber air conditioner according to claim 9, wherein the opening degree of the air-conditioning switching side electric expansion valve is adjusted within 15% to 25% of the total opening degree. The control of the multi-chamber air conditioner according to claim 9 or 10, wherein when the outdoor air temperature is higher than a predetermined temperature, the opening degree of the air-conditioning switching side electric expansion valve is closed by an opening degree corresponding to the temperature difference. Way. The multi-chamber air conditioner according to claim 9 or 10, wherein when the outdoor air temperature is lower than a preset temperature, the air-conditioning switching side electric expansion valve is opened at a preset opening degree corresponding to the temperature difference. Control method. An outdoor unit having a compressor, a four-way valve, an outdoor electric expansion valve, and an outdoor heat exchanger, a plurality of indoor units having an indoor electric expansion valve and an indoor heat exchanger, and the flow direction of the refrigerant in the indoor heat exchanger in the compressor. Or a refrigerant flow direction switching valve for converting each indoor side heat exchanger into a compressor and an indoor side heat exchanger installed at an outlet side of an indoor heat exchanger acting as an evaporator and acting as a condenser in an indoor heat exchanger acting as an evaporator. Cooling and heating switching device having an electric expansion valve for controlling the amount of refrigerant flowing into the air compressor and the compressor, and the control unit for controlling the compressor, the four-way valve, the refrigerant flow direction switching valve and the electric expansion valve and simultaneously heating and cooling the indoor units In the control method of the multi-room air conditioner to operate, Read the outdoor air temperature through the outdoor temperature sensor, Primary adjustment of the opening degree of the electric expansion valve of the air-conditioning switching device according to the read outdoor temperature, Read the inlet and outlet pipe temperature through the inlet and outlet temperature sensor of the indoor unit in the cooling operation, And controlling the opening degree of the electric expansion valve on the basis of the read inlet and outlet piping temperatures. The control method of a multi-chamber air conditioner according to claim 13, wherein, during the primary adjustment, the electric expansion valve is adjusted within 15% to 25% of the total opening. The control method of a multi-chamber air conditioner according to claim 13 or 14, wherein the electric expansion valve is first adjusted when the outdoor air temperature is lower than a preset temperature. 15. The method of claim 13, wherein if the inlet pipe temperature of the indoor heat exchanger of the cooling chamber is higher than the outlet pipe temperature during the secondary adjustment, the opening degree of the electric expansion valve is gradually opened according to a high degree, and the inlet pipe temperature is the outlet pipe temperature. If lower, the control method of the multi-chamber air conditioner characterized in that the opening degree of the electric expansion valve is gradually closed according to the low degree.