METHOD AND APPARATUS FOR CONTROLLING REFRIGERANT FLOW IN A REFRIGERATION SYSTEM

摘要

A water chiller refrigeration system is disclosed having a refrigerant expansion valve which is controlled by an electric digitally operated stepper motor. The system includes a first temperature sensor for generating an electrical analog signal corresponding with the saturated refrigerant temperature in the evaporator and a second temperature sensor for generating an electrical analog signal corresponding to the temperature of refrigerant entering the compression means of the compressor after having passed in heat exchange relation with the compressor motor. A microcomputer receives the generated temperature signals and provides a digital output signal to the stepper motor to rapidly and precisely adjust the refrigerant flow from the condenser to the evaporator in accordance with the actual superheat of refrigerant entering the compression means.