Air-conditioning apparatus

Abstract

In plural heat-source-side heat exchangers included in an outdoor unit of an air-conditioning apparatus, bypasses for defrosting are provided with flow-rate adjusting mechanisms for refrigerant flowing into the bypasses. The flow rates of the refrigerant which are to be adjusted by the flow-rate adjusting mechanisms are determined in accordance with ambient environments of plural heat-source-side heat exchangers.

1 . An air-conditioning apparatus comprising: an outdoor unit including a compressor, a flow-path switching unit and plural heat-source-side heat exchangers, the compressor, the flow-path switching unit and the heat-source-side heat exchangers being connected by pipes; and an indoor unit connected to the outdoor unit to air-condition a target space,
 wherein the outdoor unit includes:
 plural bypasses each having ends one of which is, in connection by pipes in the outdoor unit, connected to a discharge side of the compressor, and the other of which is connected to a suction side of the compressor, the bypasses being configured to cause refrigerant to flow through lower parts of the plural heat-source-side heat exchangers during a defrost operation of the air-conditioning apparatus; and 
 flow-rate adjusting mechanisms provided in the respective bypasses to adjust flow rates of refrigerant flowing into the plural bypasses. 
   
     
     
         2 . The air-conditioning apparatus of  claim 1 ,
 wherein the outdoor unit further comprises a controller and detection units configured to detect ambient temperatures of the plural heat-source-side heat exchangers, and   the controller controls the flow-rate adjusting mechanisms based on ambient temperatures which are detected by the respective detection units of the plural heat-source-side heat exchangers, and adjusts flow rates of the refrigerant flowing into the bypasses, immediately after start of the defrost operation of the air-conditioning apparatus, or after elapse of a set time from the start of the defrost operation.   
     
     
         3 . The air-conditioning apparatus of  claim 2 , wherein the flow-rate adjusting mechanisms are electronic expansion valves, and the controller adjusts opening degrees of the electronic expansion valves. 
     
     
         4 . The air-conditioning apparatus of  claim 1 , wherein the flow-rate adjusting mechanisms are capillary tubes, and the flow rates of the refrigerant flowing into the plural bypasses through the capillary tubes are set different from each other with respect to the plural heat-source-side heat exchangers.