Solar Decathlon House, Washington, D.C., 2007

"What we teach here is not just about generating energy in a building, but conserving energy within a building," says Barbara Gehrung, an assistant professor in the department of architecture at the Technical University in Darmstadt, Germany. Gehrung was one of the faculty advisers on Darmstadt's winning entry in the third annual Solar Decathlon sponsored by the U.S. Department of Energy in October 2007. The Decathlon program requires university teams to design 800-square-foot prototype houses that rely entirely on solar photovoltaics (PVs) for electricity during the 10-day competition on the National Mall in Washington, D.C.

 

Unlike other houses in the 2007 Solar Decathlon competition, Darmstadt University's house included porches in its total square footage, allowing for glass canopies for additional photovoltaics. The spaces also modulated outside air for the purposes of natural ventilation. Photos © Kaye Evans-Lutterodt (above left); Leon Schmidt/T.U. Darmstadt (above right and below).

 

Darmstadt's wood post-and-beam house incorporates photovoltaics in three ways: on the roof, on skylights, and on louvered doors. The team used Integrated Simulation Environment Language (INSEL) software, developed in Germany, to analyze the potential energy gains from the sun, as well as to lay out the best orientation for the house's active photovoltaic systems on the roof. Since the team wanted a flat roof, they realized they were at a disadvantage when compared to other houses with sloped roofs. This led them to incorporate the louvers on the east, west, and south facades.