Abstract: A refrigeration control system is disclosed for operating a refrigeration system in a very efficient manner by controlling the refrigerant pressure in the refrigerant line between the liquid receiver and the evaporator at a pressure which is just above that at which bubbles ("flashgas") occur. An electronic sight glass is used to detect such flashgas bubbles in that liquid refrigerant line thereby indicating that more cooling capacity is required to properly operate the refrigeration system. The system controller can efficiently control various refrigeration components such that the electrical power drawn by the compressor motor is at an optimal or near-optimal rate of consumption at any given cooling requirement within the refrigeration system's cooling capacity. Some of the devices that can be controlled by the system controller include condenser fans, pressure control valves, reciprocating compressors, and screw compressors.

Abstract: A refrigeration control system is disclosed for operating a refrigeration system in a very efficient manner by controlling the refrigerant pressure in the refrigerant line between the liquid receiver and the evaporator at a pressure which is just above that at which bubbles ("flashgas") occur. An electronic sight glass is used to detect such flashgas bubbles in that liquid refrigerant line thereby indicating that more cooling capacity is required to properly operate the refrigeration system. The system controller can efficiently control various refrigeration components such that the electrical power drawn by the compressor motor is at an optimal or near-optimal rate of consumption at any given cooling requirement within the refrigeration system's cooling capacity. Some of the devices that can be controlled by the system controller include condenser fans, pressure control valves, reciprocating compressors, and screw compressors.