US Patent 7270278 Distributed intelligence control for commercial refrigeration

A commercial refrigeration system including a compressor, a condenser, a valve, and an evaporator coil, all of which are in fluid communication. The refrigeration system further including a fixture adapted to be cooled by the evaporator coil, a system controller operable to control operation of the refrigeration system, and a subsystem controller in communication with the system controller. The subsystem controller being operable to monitor at least one parameter of a subsystem having at least one of the compressor, condenser, valve, and fixture, and being further operable to execute a command from the system controller to affect the operation of the subsystem.