The ABCs of DOAS (Dedicated Outdoor Air Systems)

Up to now, the use of a single HVAC unit to handle ventilation along with mechanical cooling was the aim of designers : it permitted to curb the cost of a building's mechanical system. In this article the author suggests a new design approach to treat the ventilation air and to manage the latent cooling load for the building. It consists in "splitting" the building's total cooling load with a DOAS. This approach allows each component of the HVAC system to do what it does best. The conditioned outdoor air can be delivered either directly to each occupied space or to the individual terminal units or air handlers serving those spaces. The use of DOAS is profitable, it makes the system simplified and maximize the thermal comfort.