Pursuing Net Zero Energy

This article originally published in the Department of Veterans Affairs’ ‘CFM Today’ publication in September 2012.

There has been a buzz in recent years over the idea of net-zero-energy buildings. Net-zero-energy simply means that, over the course of a year, a building generates enough renewable energy to cover its total energy usage. VA’s focus on net-zero-energy started with enactment of the Energy Independence and Security Act of 2007, which in part requires federal agencies to achieve net-zero energy in new buildings entering the planning phase in 2020 and beyond.

In August, members of CFM’s Facilities Standards Service participated in a tour of the recently constructed Net Zero Energy Residential Test Facility on the grounds of the National Institute of Standards and Technology (NIST) campus in Gaithersburg, Maryland. The net-zero-energy test facility, designed to replicate a 2,700 square foot home for a family of four people, will generate as much as fifteen percent more energy than it consumes on an annual basis. The facility uses solar photovoltaic and solar hot water systems to achieve this feat.

The project’s designers followed several simple concepts that can help all of us better understand the principles behind achieving net-zero-energy in our own facilities.

Tight Building Envelope

A building’s envelope is everything that separates interior spaces from the external environment. Walls, windows, doors, and roof all fall into this category. A key step in achieving an energy efficient building is to make the building’s envelope as tight as possible in order to minimize air and heat flow to and from conditioned spaces. Sufficient sealing and insulation contribute to a tight building envelope. The roof in the NIST facility, for example, has a thermal resistance factor, or R-value, of R-75, which is almost twice the code requirement.

Install Energy Efficient Equipment

Another important factor in achieving a highly efficient building is to specify and install energy-efficient equipment. The NIST facility has all the luxuries of a modern home. Dishwasher, refrigerator, clothes washer and dryer; the test facility has it all. The difference between the NIST facility and most homes is that the NIST facility uses only highly efficient appliances and equipment. In addition to using appliances that have the ENERGY STAR label, the home also features LED and CFL lighting and state-of-the-art heating and cooling technologies.

Integrated Design

Achieving a highly efficient design requires input from multiple design disciplines throughout every stage of design. Gone are the days where one specialist designs a specific portion of a building and then hands the design to the next specialist to add their piece. During the NIST net-zero-energy project, as well as during all VA projects, design teams work together to discuss important aspects of the design, share ideas, and ensure all aspects of the design mesh together seamlessly.

Achieving Net-Zero-Energy in VA Facilities

While VA still has a long way to go to achieve net-zero-energy in most of its new facilities, advances in technology and construction techniques promise to move VA closer to its goal of building all new facilities to achieve net-zero-energy starting in 2020. Research projects like the ones soon to be conducted at the NIST net-zero-energy test facility will break down barriers in technology and make net-zero-energy achievable in everyday facilities.