The zero net energy (ZNE) concept of designing a facility, using “no more energy than is provided by on-site renewable energy sources,” seeks to reduce energy consumption, carbon emissions, and life-cycle costs. ZNE design is an important tool as an approach to sustainable design.
My most recent accomplishment includes ZNE analysis of a new physical fitness center at Joint Base Andrews. The USAF commissioned six prototype projects throughout the country to be analyzed for ZNE concepts. The fitness center was the most challenging of the six facility types due to its function and the Mid-Atlantic climate. Our approach centered on four distinct avenues of investigation: 1) analysis of program requirements and energy consumption 2) occupant/user behavior that could be altered to reduce energy consumption 3) research and analysis of as-built ZNE precedent facilities, and 4) life-cycle cost analyses.
Using integrated design analysis and BIM technology, our team evaluated both passive and active energy reduction measures to make the concept design as efficient as possible prior to the addition of renewable energy systems. Passive measures included facility massing, orientation, daylight harvesting, shading, natural ventilation, earth berms, and building materials. Active measures included ground source heat pumps, LED lighting, solar water heating, heat exchange systems, water use management, and system controls. Analysis of renewable energy systems included wind, hydro-electric, solar, and biomass combustion on-site. Due to the site’s size, location, active air base function, and available natural resources, solar photovoltaics emerged as the most advantageous renewable energy system. Our report provides the USAF with the knowledge to make informed decisions related to zero net energy based on energy conservation, life-cycle costs, and reductions in fossil fuel use.