EP0981033A2 — Method for operating a refrigeration system in steady state operation

USPTO Abstract

A method of operating a refrigeration system in steady state operation drives the refrigerant system to the lowest capacity state which is still able to maintain operation within acceptable pressure and temperature limits. Generally, the system seeks to minimize the on and off compressor cycling. The lowest capacity state is achieved by throttling the compressor suction and by staging down the compressor operation from economized to normal and to unloaded mode while assuring that desired box temperature is maintained. Safety methods are incorporated into the system to ensure that the operation does not violate limits on suction pressure, discharge pressure, and compressor discharge temperature.