Adaptive relay-based control of household freezers with on–off actuators

This paper describes an adaptive scheme for temperature control in household freezers with low-end sensing and actuation equipment, like on–off compressors and dampers. The scheme is based on an auxiliary filter introduced in the relay loop to alter and improve the characteristics of the induced oscillation. The filter is tuned adaptively to cope with system variability and uncertainty. Some tests on detailed simulation models of a commercial appliance are reported to validate the approach and show its effectiveness with respect to both food preservation and energy consumption requirements.