A direct current (DC) powered variable capacity air conditioning system is provided. The system includes a plurality of temperature sensors for monitoring the temperature of various components, locations and air flows within the system. The system additionally includes an integrated controller board that substantially simultaneously controls a variable speed DC compressor motor, a variable speed condenser air mover and a variable speed evaporator air mover in response to inputs from the sensors. By substantially simultaneously controlling the variable speed DC compressor motor, the variable speed condenser air mover and the variable speed evaporator air mover, the system substantially simultaneously controls at least one of a temperature and a volume of an evaporator output air flow. Thus, the system provides a continuum of evaporator output air flow temperatures and capacities for maintaining an approximately constant temperature within an enclosed environment.
 This invention was made with Government support under contract DE-FC26-04NT42106, awarded by the United States Department of Energy. The Government may have certain rights in this invention.