SYSTEM AND METHOD FOR CONTROL OF A TRANSCRITICAL REFRIGERATION SYSTEM

摘要

A system and method for a CO2 refrigeration system includes a compressor, a heat exchanger, a liquid receiver, a first valve, and a valve controller. The heat exchanger operates as a gas cooler when the CO2 refrigeration system is in a transcritical mode and as a condenser when the CO2 refrigeration system is in the subcritical mode. The first valve controls a flow of refrigerant from the heat exchanger to the liquid receiver. The valve controller monitors an outdoor ambient temperature and a pressure of refrigerant exiting the heat exchanger, determines whether the CO2 refrigeration system is in the subcritical mode or in the transcritical mode, determines a pressure setpoint based on the monitored outdoor ambient temperature, and controls the first valve based on a comparison of the determined pressure setpoint and the monitored pressure when the CO2 refrigeration system is in the transcritical mode.

主权项

1. A CO2 refrigeration system, operable in a subcritical mode and a transcritical mode, comprising:
at least one compressor; a heat exchanger that receives refrigerant discharged from the at least one compressor and that is operable as a gas cooler when the CO2 refrigeration system is operating in the transcritical mode and as a condenser when the CO2 refrigeration system is operating in the subcritical mode; a liquid receiver that receives refrigerant discharged from the heat exchanger; a first valve connected between the heat exchanger and the liquid receiver, the first valve controlling a flow of refrigerant from the heat exchanger to the liquid receiver; a valve controller that monitors an outdoor ambient temperature and a pressure of refrigerant exiting the heat exchanger, determines whether the CO2 refrigeration system is operating in the subcritical mode or in the transcritical mode, determines a pressure setpoint based on the monitored outdoor ambient temperature, and controls the first valve based on a comparison of the determined pressure setpoint and the monitored pressure of refrigerant exiting the heat exchanger when the CO2 refrigeration system is determined to be operating in the transcritical mode.