Very High Efficiency DOAS Requirements

Very High Efficiency DOAS for Commercial Buildings: System Requirements and Recommendations

Dedicated outside air systems (DOAS) separate heating and cooling from the ventilation system to allow for optimal control of each of these critical building functions. Building on the DOAS concept, a very high efficiency DOAS includes heat recovery ventilation and focuses on increased equipment efficiency and optimized system design. This approach has been proven to yield significant energy and cost savings in new and existing commercial buildings while providing better indoor air quality and improved occupant comfort. When compared to a code-minimum system upgrade, very high efficiency DOAS can reduce commercial building energy use by an average of 36%, and HVAC energy use by an average of 65%.

This System Requirements and Recommendations Summary provides manufacturers, designers and installers of very high efficiency DOAS systems with performance requirements and guidance for application in the Pacific Northwest climate zones. Additionally, the document provides design guidelines for added insight into the performance specification parameters and methods, and approaches for meeting corresponding requirements.

As developed over several years of research, market analysis, and demonstration project installations, these system requirements have been proven to decrease energy consumption, improve indoor-air quality, and improve occupant comfort over conventional systems. The very high efficiency DOAS addressed in this guideline includes high-efficiency energy/heat recovery ventilation (ERV/HRV) systems to serve the ventilation load installed in combination with a high-efficiency heating and cooling system. Often, the heating and cooling is provided by multi-zone air source heat pump systems, commonly referred to as variable refrigerant flow (VRF) or variable refrigerant volume (VRV) systems. However, other high-efficiency technologies, such as mini-split ductless heat pumps (DHP), ground-source heat pumps, ground-water/ground-source heat pumps, and air-to-water heat pump central plant systems, can also meet the requirements.

Learn more about the benefits and read recent case studies of how VHE DOAS is saving buildings energy at