Dedicated outdoor air systems (DOAS) have been available for over 20 years, with the primary benefit being the ability to decouple outdoor air tempering from conditioned space thermal loads that can be handled by separate, secondary systems. Another key advantage of a DOAS is precise temperature and humidity control that may be difficult to achieve with a single air handling system such as a multi-zone VAV system.
State-of-the-art DOAS products can be used to provide precise temperature and humidity control year-round with Integrated Energy Efficiency Ratios (IEER) that exceed 20. Figure 1 shows the internal components on the supply air side of a DOAS unit from the outdoor air intake on the left to the supply fan on the right, with outdoor fans showing on top of the unit. Multiple sensors incorporated into units allow sophisticated control of components and subsystems to enhance reliability and energy performance. Remote monitoring and diagnostics allow setpoint and operational changes to be made off-site, which reduces the frequency and cost of on-site maintenance.