Air-conditioning apparatus and method of controlling the same

An air-conditioning apparatus including a plurality of heat source apparatuses each including a compressor and an accumulator configured to accumulate refrigerant to be compressed by the compressor, the air-conditioning apparatus comprising:

• a refrigerant amount calculation unit configured to calculate an amount of the refrigerant accumulated in the accumulator in one of the plurality of heat source apparatuses that is to be controlled;
• a refrigerant differential amount calculation unit configured to calculate, in a case where the number of the plurality of heat source apparatuses is two, a differential amount between the amount of the refrigerant that is calculated by the refrigerant amount calculation unit and an amount of the refrigerant in the accumulator in an other one of the heat source apparatuses, and configured to calculate, in a case where the number of the plurality of heat source apparatuses is three or more, a differential amount between the amount of the refrigerant that is calculated by the refrigerant amount calculation unit and an average amount of amounts of the refrigerant accumulated in the accumulators in the plurality of heat source apparatuses;
• and
• a liquid equalization control unit configured to control the heat source apparatus to be controlled, based on the differential amount calculated by the refrigerant differential amount calculation unit, to thereby equalize the amounts of the refrigerant accumulated in the accumulators in the plurality of heat source apparatuses,
• wherein the refrigerant amount calculation unit is configured to:
• measure a level of a liquid surface of the refrigerant accumulated in the accumulator in the heat source apparatus to be controlled, and
• calculate the amount of the refrigerant accumulated in the accumulator in the heat source apparatus to be controlled, based on the measured level of the liquid surface, a volume of the accumulator in the heat source apparatus to be controlled, and a density of the refrigerant.