Air conditioner and method for controlling air conditioner

An air conditioner, comprising:

• an outdoor unit having a compressor configured to compress a refrigerant;
• at least one indoor unit having at least one indoor heat exchanger, in which the refrigerant is heat exchanged, at least one indoor expansion valve that expands the refrigerant by adjusting an opening thereof, and at least one leak sensor that senses leakage of the refrigerant;
• a gaseous line that connects the outdoor unit and the at least one indoor unit and through which gaseous refrigerant flows;
• a liquid line which connects the outdoor unit and the at least one indoor unit and through which liquid refrigerant flows;
• at least one first shut-off valve disposed adjacent to the at least one indoor unit that opens and closes the gaseous line;
• at least one second shut-off valve disposed adjacent to the at least one indoor unit that opens and closes the liquid line;
• and
• a controller configured to control operation of the compressor and to control opening and closing of the at least one first shut-off valve, the at least one second shut-off valve, and the at least one indoor expansion valve, wherein when the at least one leak sensor senses the leakage of the refrigerant, the controller closes the at least one second shut-off valve, expands the opening of the at least one indoor expansion valve, and maintains the operation of the compressor to return the refrigerant to the outdoor unit.

A method for controlling an air conditioner, the method comprising:

• operating a compressor to perform a heating operation;
• sensing leakage of a refrigerant in at least one indoor unit using at least one leak sensor;
• and
• when the leakage of the refrigerant is sensed, closing at least one first shut-off valve and at least one second shut-off valve that control refrigerant flow between the at least one indoor unit and an outdoor unit, and expanding an opening of at least one indoor expansion valve, and a supercooling expansion valve disposed in a supercooling pipe that connects a liquid line and an inlet of the compressor.

A method for controlling an air conditioner, the method comprising:

• operating a compressor to control a plurality of indoor units to perform a cooling operation;
• sensing leakage of a refrigerant in the plurality of indoor units using at least one leak sensor;
• and
• when the leakage of the refrigerant is sensed, closing at least one second shut-off valve, expanding an opening of at least one indoor expansion valve, and maintaining operation of the compressor to return the refrigerant to an outdoor unit.