Energy management system for chilled product vending machine

摘要

A control circuit for cycling the evaporator fans on and off independently of the operation of the compressor of the refrigeration system is described. The evaporator fan is cycled on with the compressor and continues to run during the entire compressor ON cycle. A first timer causes the evaporator fan to run for an additional delay period following the cycling OFF of the compressor and the fans continue to blow air over the evaporator coil until the temperature of the evaporator coil is sufficiently above the freezing point of water (32 DEG F., 0 DEG C.). The fans are then cycled OFF. A second cycling timer is provided to intermittently cycle the evaporator fans on and off for predetermined short intervals following the above-described delay period, and during the time when the compressor is OFF. A third timer is provided to preclude freezing of the vended products and/or the evaporator coil when a vending machine is disposed in a below-freezing environment. This timer is enabled when the thermostatic temperature switch, which controls the compressor, opens, and will time out to cycle ON the evaporator fans for continuous operation for a predetermined period of time of the temperature switch remains open in excess of a predetermined period of time.