A refrigeration system comprising: a refrigerant circuit formed so that a plurality of utilization side circuits (31a, 31b) including their respective utilization side heat exchangers (33a, 33b) and valves (34a, 34b) associated with the respective utilization side heat exchangers are connected in parallel to a heat-source side circuit including a compressor and a heat-source side heat exchanger; each of the utilization side heat exchangers (33a, 33b) being capable of individually performing a heating operation to release heat from refrigerant in the utilization side heat exchanger (33a, 33b); control means that, in performing an operation in which at least one said utilization side heat exchanger (33a, 33b) in heating operation and at least one said inactive utilization side heat exchanger (33a, 33b) coexist, is configured to close the valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b); each of the utilization side heat exchangers being placed in a room and configured to release heat from refrigerant to a room air; characterized in that the valves being electric motor-operated valves (34a, 34b) and the control means is configured to fully close the electric motor-operated valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b); room temperature sensors (44, 45) for detecting the temperatures of rooms associated with the respective utilization side heat exchangers (33a, 33b) are provided around the respective utilization side heat exchangers (33a, 33b); the refrigerant circuit being configured to operate in a refrigeration cycle in which the pressure of refrigerant discharged from the compressor is at or above the critical pressure; and in that when a first specified time t1 has passed since full closure of the electric motor-operated valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b), the control means temporarily opens the electric motor-operated valve (34a, 35b) for a second specified time t2; the refrigeration system further comprising a correction means that corrects one or both of the first specified time t1 and the second specified time t2 based on the temperature detected by the room temperature sensor (44, 45) associated with the at least one inactive utilization side heat exchanger (33a, 33b). a refrigerant circuit formed so that a plurality of utilization side circuits (31a, 31b) including their respective utilization side heat exchangers (33a, 33b) and valves (34a, 34b) associated with the respective utilization side heat exchangers are connected in parallel to a heat-source side circuit including a compressor and a heat-source side heat exchanger; each of the utilization side heat exchangers (33a, 33b) being capable of individually performing a heating operation to release heat from refrigerant in the utilization side heat exchanger (33a, 33b); control means that, in performing an operation in which at least one said utilization side heat exchanger (33a, 33b) in heating operation and at least one said inactive utilization side heat exchanger (33a, 33b) coexist, is configured to close the valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b); each of the utilization side heat exchangers being placed in a room and configured to release heat from refrigerant to a room air; characterized in that the valves being electric motor-operated valves (34a, 34b) and the control means is configured to fully close the electric motor-operated valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b); room temperature sensors (44, 45) for detecting the temperatures of rooms associated with the respective utilization side heat exchangers (33a, 33b) are provided around the respective utilization side heat exchangers (33a, 33b); the refrigerant circuit being configured to operate in a refrigeration cycle in which the pressure of refrigerant discharged from the compressor is at or above the critical pressure; and in that when a first specified time t1 has passed since full closure of the electric motor-operated valve (34a, 34b) associated with the at least one inactive utilization side heat exchanger (33a, 33b), the control means temporarily opens the electric motor-operated valve (34a, 35b) for a second specified time t2; the refrigeration system further comprising a correction means that corrects one or both of the first specified time t1 and the second specified time t2 based on the temperature detected by the room temperature sensor (44, 45) associated with the at least one inactive utilization side heat exchanger (33a, 33b).