By Patricia Daukantas
On the National Mall, practically on the doorstep of Washington, D.C.’s decision-makers, 20 teams of undergraduate and graduate students have spent the past week living on solar power.
The third-ever Solar Decathlon pits the collegians from the United States, Canada, Germany and Spain in a competition to design the kinds of completely solar-powered houses that our great-grandchildren may someday live in.
The Solar Decathlon gets its name from the 10 separate categories in which entries are judged: architecture, engineering, market viability, communications (with the public), comfort zone, appliances, hot water, lighting, energy balance and getting around (in small, street-legal electric vehicles powered off the house’s solar-power supply). As in the Olympic track-and-field decathlon, each contest nets the competitor a certain number of points, but there can be only one victor.
The categories reflect the notion that, to be successful, a solar-powered house must actually be comfortable to live in. It can’t be too hot or too cold, it must provide enough hot water for the dishwasher and the showers, and it should look reasonably attractive.
Two years ago, when I wrote about the 2005 Solar Decathlon, the weather had been cloudy for nearly the entire competition, and team members struggled to capture the available photons. This year, drought conditions in the mid-Atlantic region have caused plenty of clear October skies—and a lot more sunshine to work with for most of the week. (Cloudy weather rolled in yesterday, with some light rain today.)
Early in the week, the team from the Technical University of Darmstadt, Germany, was in the top spot. But after winning the communications contest, the University of Maryland—which, with its location in the Washington suburbs, is effectively the home team—took the lead and kept it for several days. Late this afternoon, however, Darmstadt was declared the overall victor.
Maryland’s so-called LEAF House uses 34 Sanyo HIT-205BA3 photovoltaic (PV) panels, which together generate 6,970 W of electricity in full sunshine. Low-mercury fluorescent bulbs and reflectors provided the overall indoor lighting with heavy use of LEDs, attached to a central dimming system, for task lighting.
The Darmstadt students, who had to send their entry across the Atlantic via container ship, placed Schott amorphous silicon PV panels on three sides of their house to supplement the 40 Sunpower SPR-210 roof-mounted panels. The team integrated LEDs into the ceiling, furniture and deck while providing ambient lighting through translucent wall panels.
Similar details on the other 18 houses in the competition—plus information on scoring criteria, blog entries and lots of photos—are available through links from the main Solar Decathlon Web site.
The Solar Decathlon is already accepting proposals for the October 2009 competition. The chosen participants will get a two-year, $100,000 grant toward solar-technology research. Also, American and Spanish officials are beginning plans for a European Solar Decathlon in 2010.
If you are near Washington and want to check out this year’s crop of futuristic homes, better move fast—tomorrow’s the last day of public display.
The solar village at night takes on a different appearance, especiallywhen the houses are lit up for the Lighting contest. In this photo, theCarnegie Mellon house looks lovely in the glow cast on the greenscape.(Credit: Kaye Evans-Lutterodt/Solar Decathlon)