Multi-unit air conditioner and method for controlling the same

1. A multi-unit air conditioner comprising:

a plurality of indoor units each comprising a power controller adapted to independently power on or off an associated one of the indoor units;

an outdoor unit connected with the indoor units, the outdoor unit comprising a microcomputer for controlling an operation of the outdoor unit, and enabling the outdoor unit to communicate with the indoor units;

at least one controller for determining whether each of the indoor units is in an operation state or in a non-operation state, and controlling an operation of a distributor in accordance with the result of the determination;

a refrigerant line connected to the outdoor unit;

branch refrigerant lines connected between the refrigerant line and the plurality of indoor units;

sub electronic expansion valves respectively arranged in the branch refrigerant lines; and

a main electronic expansion valve arranged in the refrigerant line, and

a plurality of first valves provided in the respective branch refrigerant lines,

wherein the at least one controller controls at least one of the plurality of first valves to be closed when a corresponding indoor unit is determined to be in the non-operation state, and controls the corresponding indoor unit to be operated for a predetermined period of time after the closing of at least one of the plurality of first valves.

2. The multi-unit air conditioner according to claim 1 , wherein the at least one controller is installed in at least one of the outdoor unit and the distributor, respectively.

3. The multi-unit air conditioner according to claim 1 , further comprising:

at least one second valve arranged in a refrigerant line through which the refrigerant from the indoor units is discharged into the outdoor unit.

4. The multi-unit air conditioner according to claim 3 , wherein each of the first and second valves is a solenoid valve controlled by the controller.

5. The multi-unit air conditioner according to claim 3 , wherein each of the first and second valves is a solenoid valve controlled by the microcomputer of the outdoor unit.

6. The multi-unit air conditioner according to claim 3 , wherein:

the at least one second valve comprises a plurality of second valves respectively arranged in branch refrigerant lines, through each of which the refrigerant from an associated one of the indoor units is discharged into the outdoor unit.

7. A multi-unit air conditioner comprising:

a plurality of indoor units;

an outdoor unit connected with the indoor units, the outdoor unit comprising a microcomputer for controlling an operation of the outdoor unit, and enabling the outdoor unit to communicate with the indoor units;

an electronic expansion valve arranged in a refrigerant line through which a refrigerant from the outdoor unit is introduced into the indoor units;

first valves arranged in a refrigerant line through which the refrigerant is introduced into the indoor units;

second valves arranged in a refrigerant line through which the refrigerant from the indoor units is discharged into the outdoor unit; and

at least one controller for determining whether each of the indoor units is in an operation state or in a non-operation state, and controlling an operation of a distributor in accordance with the result of the determination, the at least one controller being arranged in at least one of the outdoor unit and a distributor, respectively,

wherein the electronic expansion valve comprises:

sub electronic expansion valves respectively arranged in branch refrigerant lines, through each of which the refrigerant is introduced into an associated one of the indoor units; and a main electronic expansion valve arranged in the refrigerant line, through which the refrigerant is introduced into the indoor units, and which is branched into the branch refrigerant lines

wherein at least one of the first valves is controlled to be closed when a corresponding indoor unit is determined to be in the non-operation state, and the corresponding indoor unit is controlled to be operated for a predetermined period of time after the closing of the at least one of the first valves.

8. The multi-unit air conditioner according to claim 7 , wherein each of the first valves is arranged between an associated one of the sub electronic expansion valves and the indoor unit associated with the associated sub electronic expansion valve.

9. The multi-unit air conditioner according to claim 7 , wherein the electronic expansion valve and the first and second valves are controlled by the microcomputer of the outdoor unit.

10. The multi-unit air conditioner according to claim 7 , wherein the electronic expansion valve and the first and second valves are controlled by the controller.

11. The multi-unit air conditioner according to claim 7 , wherein each of the first and second valves is a solenoid valve controlled by the controller.

12. A multi-unit air conditioner comprising:

a plurality of indoor units;

an outdoor unit connected with the indoor units;

at least one controller for determining whether each of the indoor units is in an operation state or in a non-operation state, and controlling an operation of a distributor in accordance with the result of the determination;

refrigerant lines connected between the indoor units and the outdoor unit to allow refrigerant to flow from the outdoor unit to the respective indoor units; and

valves arranged in the respective refrigerant lines,

wherein the at least controller controls at least one of the valves to be closed when the corresponding indoor unit is determined to be in the non-operation state, and controls the corresponding indoor unit to be operated for a predetermined period of time after the closing of the at least one of the valves.