REFRIGERATOR ENERGY AND TEMPERATURE CONTROL

Apparatus and methodologies are provided to improve the refrigeration system (10) by precisely controlling refrigerator compartment and heat exchanger temperatures through continuous modulation of device speeds or positions to match capacity with instantaneous load. A controller (302) in a refrigerator (300) is configured to provide a plurality of control loops to control various operational aspects of selected components in the refrigerator. A first loop controls the operating speed of a compressor (364) based on temperature of the evaporator (370) or based on the desired speed of an evaporator fan (374). A second control loop controls speed of an evaporator fan (374) to maintain a prescribed freezer compartment (314) temperature. A third control loop maintains a prescribed temperature in a fresh food compartment (312). In certain embodiments selected of the control loops may be thermodynamically coupled by way of thermal interaction between the various cooled compartments rather than being electrically coupled. The control loops may be individually configured as one of a proportional, proportional-integral, or proportional-integral-derivative control loop.