Air-conditioning apparatus

An air-conditioning apparatus, comprising:

• a main circuit including a compressor, a plurality of indoor heat exchangers, a plurality of pressure reducing devices, and an outdoor heat exchanger which are successively connected by pipes, the outdoor heat exchanger including a plurality of parallel heat exchangers;
• a first defrosting pipe branching off from the main circuit to supply a portion of refrigerant discharged from the compressor to one of the parallel heat exchangers which is to be defrosted;
• a first expansion device provided at the first defrosting pipe;
• a second defrosting pipe configured to return to the main circuit, the refrigerant supplied through the first defrosting pipe to the parallel heat exchanger to be defrosted;
• a first flow switching device configured to switch connection of each of the parallel heat exchangers on an end side thereof which is connected to the compressor, between connection to the first defrosting pipe and connection to the main circuit;
• a second expansion device provided on the second defrosting pipe, and configured to adjust a pressure of the refrigerant in the parallel heat exchanger to be defrosted;
• a flow control device provided between a connection point between an outlet of the second defrosting pipe and the main circuit and at least one of the indoor heat exchangers which function as evaporators, the flow control device being configured to switch connection of each of the parallel heat exchangers on an opposite end side of the end side connected to the compressor, between connection to the second defrosting pipe and connection to the main circuit, and adjust a pressure of the refrigerant in the at least one of the indoor heat exchangers which function as the evaporators;
• and
• a controller configured to control the first expansion device, the second expansion device, and the flow control device,
• wherein the controller controls the second expansion device and the flow control device individually in a first operation in which:
• a portion of the refrigerant discharged from the compressor is guided through the first defrosting pipe and the second defrosting pipe to pass through the parallel heat exchanger to be defrosted;
• at least one of the parallel heat exchangers, which are other than the parallel heat exchanger to be defrosted, are caused to function as evaporators;
• and at least one of the indoor heat exchangers are caused to function as evaporators, and an other at least one of the indoor heat exchangers are caused to function as condensers, and
• when the first operation is changed to a second operation in which:
• all the parallel heat exchangers function as evaporators;
• and at least one of the indoor heat exchangers function as evaporators and an other at least one of the indoor heat exchangers function as condensers, or when the second operation is switched to the first operation, the controller controls the flow control device based on a ratio of a cooling load of the at least one of the indoor heat exchangers which function as the evaporators to a heating load of the other at least one of the indoor heat exchangers which function as the condensers.