September Chapter Meeting: Maximizing HVAC Efficiency, Flexibility, and Resiliency with Very High Efficiency Dedicated Outdoor Air Systems

With the ever-increasing environmental impacts of local pollution, extreme weather events and wildfires, there is a necessity for resilient, flexible, and extremely efficient HVAC systems. Unfortunately, while HVAC systems are critical to our comfort and well-being, conventional systems are costly to operate and contribute to over 50% of total energy usage in commercial buildings. Dedicated outdoor air systems (DOAS) are a proven solution for reducing energy consumption since they optimize the control and functionality of ventilation and thermal comfort separately. A very high efficiency approach to DOAS maximizes energy efficiency by decoupling ventilation air from comfort conditioning, including air-to-air heat recovery, right-sizing of a high efficiency heating and cooling system and minimizing fan power. This allows for many benefits, including:

• Demonstrated reduction of building HVAC energy use by an average of 69% over conventional systems,
• Excellent indoor air quality (IAQ) and thermal comfort,
• Proven flexibility and resiliency to adapt to changing occupant densities, increased IAQ requirements, and extreme weather events,
• Significant carbon emission reduction with minimal peak electric demand increases in sites that convert from gas to electric heat.

In partnership with local utilities and HVAC experts, this system approach has been installed and monitored in 12 small-to-medium commercial buildings, including in cold climates, that resulted in an average 69% reduction in HVAC energy use and a 48% reduction in whole-building energy use when compared to a code minimum system (often a packaged RTU). Attendees will learn the cost and energy savings outcomes of these Northwest-based projects. Additional topics to discuss include:

• WSEC 403.3.5 – Dedicated outdoor air systems
• WSEC 406.2.2.6 – High performance DOAS measure (as many as 40 additional energy efficiency credits)
• Economics of VHE DOAS vs. WSEC minimum
• ERV technologies that achieve 82% sensible recovery (micro-channel counter-flow HX, advanced rotary wheel HX, reciprocating dual-core HX)

Jordan Pratt, PE, CEM

Jordan is a Mechanical Engineer with a passion for energy efficiency. He has experience analyzing complex mechanical systems as well as installing, commissioning, metering, and testing a variety of equipment and systems. Prior to joining Energy 350, Jordan worked as a mechanical design engineer specializing in high performance and sustainable systems. Jordan is a registered Professional Engineer (PE) in Oregon and received a B.S. in Energy and Design Engineering and a M.S. in Sustainable Design and Construction from Stanford University.