The ABCs of DOAS: Dedicated Outdoor Air Systems PDF

To curb the initial cost of a building’s mechanical systems, designers have expended much time and effort to use a single HVAC unit to handle ventilation as well as mechanical cooling. High-occupancy spaces, such as classrooms, pose a particular challenge. This article explores the benefits of "splitting" the cooling load, that is, using a dedicated outdoorair unit to treat high latent-cooling load of outdoor air and zone-mounted terminal units to treat high sensible-cooling load of indoor air. Treating outdoor air separately makes it easy to verify sufficient ventilation airflow and enforces the maximum limit for relative humidity in occupied zones.