Abstract: An evaporator setpoint temperature for a refrigeration system is adjusted by an electronic control module to maximize a ratio of volume of condensate produced per unit of electricity consumed. When the control module detects a change in the relative humidity of air entering an evaporator in the refrigeration system, the module determines the new dew point for the air, compensates the dew point value by a predetermined offset value, and changes the setpoint for refrigerant temperature in the evaporator to the compensated dew point value. The control module operates the refrigeration system to drive the evaporator temperature to the compensated dew point value. Refrigeration system parameters measured and modified by the control module include operating speed of compressors, number of operating compressors, refrigerant flow through an expansion valve, compressor suction pressure, and fan speeds for the condenser and evaporator.