The selection of the optimum supply air temperature for a heating, ventilating, and air-conditioning (HVAC) system is highly system and application dependent. Current ASHRAE literature gives the designer considerable latitude in selecting the design supply air temperature. With the current use of ice storage systems for the purposes of reducing electrical demand there is an opportunity to reduce fan energy consumption in order to eliminate the refrigeration penalty associated with ice thermal energy storage systems. The supply of 40°F air directly to the room will reduce the air quantity, size of the air distribution system, and fan energy. This paper discusses the potential problems of supplying 40°F air to a room, recommends design guidelines, and shows through two case studies that 40°F air can be successfully supplied to a room producing a comfortable environment under all operating conditions.

KEYWORDS: Supply air, cold air distribution, air diffusers, air distribution equipment, air handlers.