What is the ideal combination of building science techniques, design features, and products to build a mainstream net-zero house? The National Institute of Standards and Technology (NIST) aims to find out. Under construction on the NIST campus in Gaithersburg, Md., the Net Zero Energy Residential Test Facility—a two-story, 2,700-square-foot home—will provide researchers the opportunity to “develop and demonstrate the measurement science needed to achieve net-zero-energy homes.”
In addition to showcasing the viability of net-zero building, the house will serve as a living laboratory by simulating (via robotics and a control room in the detached garage) the lifestyle of a typical family of four. The ongoing, real-world field data could help move a broader swath of the country closer toward net-zero homes, including, according to NIST, by:
helping to improve models used to predict energy production of solar systems
developing measurement science to capture the efficiencies of various techniques for distributing conditioned air
improving models used to predict energy consumption
evaluating of the relative merits of various building control systems
analyzing the interaction between the building envelope, HVAC systems, and photovoltaics.
Along with an ultra-tight envelope and other efficiency-boosting details (see “Performance Details,” right), the team will install several duplicate systems that can be operated and measured independently, allowing for ongoing, comparative research. This includes three geothermal piping schemes (slinky loop, vertical loop, and horizontal loop) and three separate sets of ductwork; the home also will be prepped for future installation of mini-split systems.
The reconfigurable photovoltaic system will allow researchers to select a power output between 1.6 and 9.7 kW. Similarly, the solar thermal setup features a variable collector array size and storage tank capacity.
Participating in the project was a no-brainer for Bethesda Bungalows, which won the federal contract to serve as the prime subcontractor for the build. The Chevy Chase, Md.-based builder has enthusiastically embraced high-performance building during the past few years and was eager for the chance to dig even deeper. “There’s a lot to be learned here,” says Brad Beeson. What’s more, “It establishes us as a leader in the green building industry in the area. It helps to cement that reputation.” (See EcoHome’s ongoing coverage of the firm’s latest green project here and its award-winning Incredibly Green Home here.)
Along with Bethesda Bungalows, the team includes a number of building performance experts and organizations, including commercial builder Therrien Waddell, consulting firm Building Science Corp., and the DOE’s Building America program.
The house is designed to achieve LEED-Platinum, Energy Star Version 3.0, and Indoor Air Plus. Its official groundbreaking will take place March 25, with a scheduled completion target of Spring 2012.
Katy Tomasulo is Deputy Editor for EcoHome.