After three years of development, 16 months of construction, and an official ribbon-cutting ceremony on Sept. 12, the Net-Zero-Energy Residential Test Facility is now operational on the U.S. Commerce Department’s National Institute of Standards and Technology (NIST) campus in Gaithersburg, Md. The goal of the facility is four-fold, according to S. Shyam Sunder, director of the engineering laboratory at NIST: to demonstrate net-zero-energy capability, to serve as a test bed for advanced technologies, to quantify energy use, and to compare installed use to controlled use.
“We want to demonstrate that energy efficiency does not need to be at odds with a typical suburban neighborhood,” said NIST director and Under Secretary of Commerce for Standards and Technology Patrick Gallagher at the ribbon-cutting ceremony. “We think that by demonstrating that it’s possible to have the home design you want, with the energy efficiency you want, we’ll help speed the adoption of energy-efficient technologies and net-zero homes.”
The home, which is designed to achieve Energy Star Version 3.0 and Indoor airPLUS, was constructed to replicate typical features of homes in the Washington, D.C., area while integrating various energy-efficient systems. For example, the earth-coupled heat pump system features three fields—one with three vertical well loops where one, two, or all three can be activated; variable-length horizontal loops; and a slinky loop—that can be monitored and measured. The photovoltaic array can be reconfigured so that researchers can control the power output (between 2.6 kW and 10.2 kW), reconfigure DC to AC inverters, and change out modules on the rack-mount system to test new technologies. The PV system should generate enough electricity to power lights and appliances when weather permits, and excess energy will be fed into the local utility grid via a smart electric meter. On low-sun days that do not generate enough power for the house, the facility will pull power from the grid. It is anticipated, however, that it will produce enough over the course of a year to make up for any purchased energy, thus achieving net-zero-energy usage.
The home has multiple zoning capabilities for air distribution (floor, register, and perimeter vs. central), and is outfitted with a conventional duct system, a small duct, high-velocity system, and dedicated humidification-dehumidification-heat recovery systems ductwork. It also has some features that are traditionally commercial elements, such as several bioretention ponds surrounding the house. The structure features no gutters. Instead, stormwater is channeled to a 2-foot gravel perimeter, where it is then fed into corrugated piping that feeds it to the bioretention ponds. The fire detection and suppression systems, which are interfaced to NIST’s emergency services division, are also commercial grade, according to Stella Fiotes, director of the office of facilities and property management at NIST.
Every electrical circuit in the 2,700 square feet of living space and 1,500-square-foot unfinished basement is instrumented for measurement of point-of-use energy consumption. No one, however, will actually live in the home. For the first year, researchers will use the LEED-Platinum, two-story, four-bedroom home to demonstrate net-zero-energy usage for a virtual family of four. No humans will be allowed to enter the house during this year. Instead, mechanical controls and computer software (which are separated from the home in a detached garage) will activate the lights, hot water, and appliances at specific times and small devices in the home will emit heat and humidity to simulate the human occupants. NIST plans to make the data gathered during this year-long experiment available online.
Following the year-long experiment, NIST will begin developing methods of testing and metrics for emerging technologies, and will also plug and play different technologies to create different environments for extended testing.
The project was funded by the American Recovery and Reinvestment Act of 2009 and architectural design, training, and management support was provided by the Department of Energy through its Building America effort. It was designed by Building Science Corp., and constructed by contractor Therrin Waddell and subcontractor Bethesda Bungalows.
View videos of the Net-Zero-Energy Residential Test Facility: