Explores the energy savings and first cost advantages of combining an indirect/evaporative cooling air handling unit design with that of a thermal energy storage (TES) central plant in the arid western climate of the USA. Notes that the physical size and consequently the installed cost of TES systems may be substantially reduced when evaporative cooling augments mechanical cooling., By collecting and routing the building return air through the exhaust side of an air to air heat exchanger much of the energy in the exhaust airstream can be recycled, precooling or preheating the incoming outdoor air. In the cooling cycle the exhaust side of the air to air heat exchanger may be wetted, allowing the dry building exhaust air to evaporate some of this water and thereby enhancing the heat exchanger's ability to extract heat from the hot entering outdoor airstream. Describes in some detail and analyses the operation of an evaporative cooling concept as one of several load reduction techniques that will make a TES a better investment for the owner. Notes benefits beyond installation and operating cost savings.