Air-conditioning apparatus

An air-conditioning apparatus comprising:

• a plurality of heat source units each including a compressor, a heat-source-side heat exchanger, a flow control valve, an accumulator, a bypass pipe that allows refrigerant to flow from a discharge side of the compressor to the accumulator, and a bypass adjusting valve configured to adjust a flow rate of refrigerant that flows in the bypass pipe;
• a use-side load connected to the heat source units by pipes, and including a use-side heat exchanger configured to cause heat exchange to be performed between refrigerant supplied from each of the heat source units and a use-side heat medium;
• a controller configured to control an operation of each of the heat source units;
• discharge temperature detection units each configured to detect a temperature of refrigerant discharged from the compressor of an associated one of the heat source units;
• and
• discharge pressure detection units each configured to detect a pressure of refrigerant discharged from the compressor of the associated heat source unit,
• wherein the controller includes
• a determination unit configured to determine whether or not a current operation is a non-normal operation in which the heat source units and the use-side load operate in a different manner from that in a heating operation or a cooling operation,
• a liquid equalization unit configured to equalize amounts of liquid refrigerant that flows in the heat source units, when the determination unit determines that the current operation is the non-normal operation, and
• a time measuring unit configured to measure time for which each of the heat source units operates,
• the determination unit is configured to determine that the current operation is the non-normal operation, when the time measured by the time measuring unit is less than a first time threshold or exceeds a second time threshold, or a discharge superheat degree calculated based on the temperature detected by the discharge temperature detection unit and the pressure detected by the discharge pressure detection unit is less than a discharge superheat degree threshold, and.
• the liquid equalization unit is configured to adjust the bypass adjusting valve of one of the heat source units that is determined to be in the non-normal operation by the determination unit.

An air-conditioning apparatus comprising:

• a plurality of heat source units each including a compressor, a heat-source-side heat exchanger, a flow control valve, and an accumulator;
• a use-side load connected to the heat source units by pipes, and including a use-side heat exchanger configured to cause heat exchange to be performed between refrigerant supplied from each of the heat source units and a use-side heat medium;
• a controller configured to control an operation of each of the heat source units;
• discharge temperature detection units each configured to detect a temperature of refrigerant discharged from the compressor of an associated one of the heat source units;
• and
• discharge pressure detection units each configured to detect a pressure of refrigerant discharged from the compressor of the associated heat source unit,
• wherein the controller includes
• a determination unit configured to determine whether or not a current operation is a non-normal operation in which the heat source units and the use-side load operate in a different manner from that in a heating operation or a cooling operation,
• a liquid equalization unit configured to equalize amounts of liquid refrigerant that flows in the heat source units, when the determination unit determines that the current operation is the non-normal operation, and
• a time measuring unit configured to measure time for which each of the heat source units operates,
• the determination unit is configured to determine that the current operation is the non-normal operation, when the time measured by the time measuring unit is less than a first time threshold or exceeds a second time threshold, or a discharge superheat degree calculated based on the temperature detected by the discharge temperature detection unit and the pressure detected by the discharge pressure detection unit is less than a discharge superheat degree threshold, and
• the liquid equalization unit is configured to adjust the flow control valve of one of the heat source units that is determined to be in the non-normal operation by the determination unit.