Air-conditioning apparatus

Abstract

Provided is an air-conditioning apparatus configured so that a decrease in a refrigeration capacity can be suppressed without increasing the amount of refrigerant with which a refrigerant circuit is filled and that refrigerant can be suitably stored during a pump down operation. The air-conditioning apparatus includes a first on-off valve provided at a pipe between an expansion valve and a use side heat exchanger, a bypass branching from a pipe between the expansion valve and the first on-off valve and connected to a pipe at a suction-side of a compressor, and a refrigerant storage unit configured to store the refrigerant having passed through the bypass. In a pump down operation in which the compressor operates with the first on-off valve being in a closed state, the refrigerant having flowed out from the heat source side heat exchanger flows into the bypass, and then, is stored in the refrigerant storage unit.

1 . An air-conditioning apparatus comprising:
 a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion valve, and a use side heat exchanger are connected by pipes, and refrigerant circulates;   a first on-off valve provided at a pipe between the expansion valve and the use side heat exchanger;   a bypass branching from a pipe between the expansion valve and the first on-off valve or a pipe between the heat source side heat exchanger and the expansion valve and connected to a pipe on a suction side of the compressor; and   a refrigerant storage unit configured to store the refrigerant passed through the bypass, the refrigerant storage unit storing the refrigerant flowing into the bypass from the heat source side heat exchanger in a pump down operation in which the compressor operates with the first on-off valve being in a closed state.   
     
     
         2 . The air-conditioning apparatus of  claim 1 , further comprising:
 a first bypass on-off valve provided on a refrigerant inflow side of the bypass; and   a second bypass on-off valve provided on a refrigerant outflow side of the bypass,   wherein the refrigerant storage unit comprises a container storing the refrigerant, and is provided at the bypass between the first bypass on-off valve and the second bypass on-off valve,   the pump down operation is performed with the first bypass on-off valve being in an open state and the second bypass on-off valve being in the closed state, and   the refrigerant flowing into the bypass is stored in the container.   
     
     
         3 . The air-conditioning apparatus of  claim 1 , further comprising a second expansion valve provided at the bypass,
 wherein the refrigerant storage unit comprises an accumulator provided on the suction side of the compressor,   the bypass is connected to a pipe between an inflow side of the accumulator and the use side heat exchanger, and   in the pump down operation,
 the refrigerant flowing into the bypass is expanded by the second expansion valve, and then, flows into the accumulator, and 
 the refrigerant flowing into the accumulator is stored. 
   
     
     
         4 . The air-conditioning apparatus of  claim 1 , further comprising a gas-liquid separator provided at the pipe between the expansion valve and the first on-off valve,
 wherein the bypass connects a gas side of the gas-liquid separator and the pipe on the suction side of the compressor, and   in a cooling operation in which the heat source side heat exchanger serves as a condenser and the use side heat exchanger serves as an evaporator,
 a gaseous refrigerant separated by the gas-liquid separator flows into the bypass. 
   
     
     
         5 . The air-conditioning apparatus of  claim 1 , further comprising a gas-liquid separator provided at the pipe between the heat source side heat exchanger and the expansion valve,
 wherein the bypass connects a gas side of the gas-liquid separator and the pipe on the suction side of the compressor, and   in a heating operation in which the heat source side heat exchanger serves as an evaporator and the use side heat exchanger serves as a condenser,
 a gaseous refrigerant separated by the gas-liquid separator flows into the bypass.