Refrigeration air conditioner, operation control method of refrigeration air conditioner, refrigerant amount control method of refrigeration air conditioner

摘要

In a refrigerating air conditioning system using refrigerant such as CO 2 used in a supercritical area, a highly efficient refrigerating air conditioning system is provided by adjusting the amount of refrigerant in a radiator which contributes to the efficiency of the system stably and quickly. During heat utilizing operation, the superheat at the exit of an evaporator 5 is controlled to a predetermined value by controlling the opening of an expansion valve 6 provided on the upstream side of the evaporator 5, and an expansion valve 9 is controlled so that the state of refrigerant in a connecting pipe on the high-pressure side becomes a supercritical state. In this state, a flow rate control valve 13 is controlled to change the density of the refrigerant stored in a refrigerant storage container 12 and the amount of refrigerant existing in the radiator 10 is adjusted. A target high-pressure value and a target value of the radiator exit temperature are set and the capacity of the compressor 3 is controlled to obtain the target values, and the amount of refrigerant existing in the radiator 10 is adjusted by the refrigerant amount adjusting circuit 20.