GSA’s Green Proving Ground (GPG) program is one of the ways GSA advances the performance of our federal buildings. Designed to overcome new technology adoption barriers, GPG tests emerging technologies in GSA’s buildings to assess the impacts of real-world conditions. With results from these evaluations, GSA can use evidence-based information to spur the deployment of high-performing new technologies throughout GSA’s portfolio.
Today, GPG is announcing the release of evaluation results for three innovative technologies in the fields of renewable energy, building envelope, and water conservation.
Photovoltaic-Thermal (PV-T) Hybrid Solar Systems
In order to convert solar radiation into electricity, standard photovoltaic systems need a lot of sunlight, but shed a lot of excess heat in warmer climates. Photovoltaic-thermal (PV-T) hybrid solar systems address this problem by using a solar-thermal collector to capture that excess heat in a way that is useful for heating domestic water. In 2011, GPG commissioned the National Renewable Energy Laboratory to assess the performance of the nation’s first large-scale PV-T system installed at the Thomas P. O’Neill, Jr. Federal Building in Boston, MA. The evaluation found numerous lessons in system design, as well as operational best practices and deployment recommendations. Modeling found that PV-T should target buildings in locations with high utility costs and electric hot water backup, such as Honolulu, HI.
Applied Solar-Control Retrofit Films
Heat gain through windows accounts for a third of cooling energy demand in U.S. commercial buildings. Applied solar-control films can reduce that demand by reflecting or absorbing solar energy before it reaches interior spaces. In 2012, GPG commissioned Lawrence Berkeley National Laboratories to assess the performance of a liquid-applied, spectrally-selective absorbing film at the Goodfellow Federal Center in St. Louis, MO. Using results from St. Louis, LBNL modeled the energy performance of both spectrally-selective absorbing and reflective films in a range of climates and found potential combined heating and cooling savings of up to 29 percent with reflective films.
Weather-Station for Irrigation Control
Timer-based irrigation systems have been found to overwater landscapes by up to 50 percent–which could substantially contribute to outdoor water consumption at GSA sites. Weather-based irrigation control, by contrast, use local weather data to measure and respond to actual irrigation needs. In 2013, GPG commissioned the Pacific Northwest National Laboratory to assess an innovative smart-irrigation solution that connects a weather station to the building automation system (BAS) at the Hart-Dole-Inouye Federal Center in Battle Creek, MI. While, at present, connecting the weather station to the BAS remains a challenge, the potential 66 percent water savings demonstrated in Battle Creek supports the effectiveness of turnkey weather-based systems at landscaped sites in GSA’s portfolio.
Find these reports, 15 previously released reports, and more information about GSA’s Green Proving Ground program at www.gsa.gov/GPG.