Heat source unit and refrigeration apparatus

Abstract

A heat source unit includes a heat-source-side circuit and a controller. In the heat-source-side circuit, an expansion valve is located between a heat-source-side heat exchanger and a receiver. while the compression element of the heat-source-side circuit is stopped, the controller controls the expansion valve based on one or both of a refrigerant pressure in the receiver and a refrigerant pressure in the heat-source-side heat exchanger.

1 . A heat source unit connected to a utilization-side unit and configured to perform a refrigeration cycle, the heat source unit comprising:
 a heat-source-side circuit including a compression element with one or more compressors, a heat-source-side heat exchanger, an expansion valve, and a receiver; and   a controller configured to control the expansion valve,   wherein   in the heat-source-side circuit, the expansion valve is located between the heat-source-side heat exchanger and the receiver, and   while the compression element is stopped, the controller controls the expansion valve based on one or both of a refrigerant pressure in the receiver and a refrigerant pressure in the heat-source-side heat exchanger.   
     
     
         2 . The heat source unit of  claim 1 , wherein
 the controller switches the expansion valve to a closed state in response to a stop of the compression element, and thereafter performs a first operation to turn the expansion valve to an open state if the refrigerant pressure in the heat-source-side heat exchanger becomes lower than a first pressure.   
     
     
         3 . The heat source unit of  claim 2 , wherein
 after performing the first operation, the controller performs a second operation to turn the expansion valve to a closed state if the refrigerant pressure in the receiver becomes higher than a second pressure.   
     
     
         4 . The heat source unit of  claim 3 , wherein
 the heat-source-side circuit includes a venting passage configured to send a gas refrigerant in the receiver to the compression element, and   after performing the second operation, the controller performs a third operation to activate the compression element to suck the gas refrigerant in the receiver into the compression element through the venting passage if the refrigerant pressure in the receiver becomes higher than a third pressure.   
     
     
         5 . The heat source unit of  claim 1 , wherein
 the heat-source-side circuit is charged with carbon dioxide as a refrigerant.   
     
     
         6 . A refrigeration apparatus comprising:
 the heat source unit of  claim 1 ; and   a utilization-side unit connected to the heat source unit.