The Solar Decathlon, run by the US Department of Energy (and sponsored in part by Popular Mechanics) is held every 2 years on the National Mall in Washington, D.C. The competition in 2009 saw some surprising entries and innovative solutions to passive design and solar technology. A selection of 20 college teams competed in the fields of architecture and engineering to design, build and operate the most attractive and energy-efficient solar powered home. Winners of the competition gain international recognition for their designs.

© Image by Stefano Paltera/US Dept. of Energy Solar Decathlon.

© Image by asla.org.

Hard-hatted Department of Energy inspectors roamed the Solar Decathalon job sites with check lists, stopping during PM’s stay to ask the workers, “Your PV situation under control? Any code violations I should know about?” The Hokies, like many on the Mall the first day, were still scrambling to get their house rebuilt in a matter of hours after shipping it to DC from Blacksburg, Virginia.

The team had already completed the heart of the system—a responsive pair of sliding panels designed to maximize the house’s efficiency in changing weather conditions. Faculty advisor Bob Schubert walked PM through the five layers that compose the system, which sandwiches each of the rectangular house’s longer north and south sides. On the exterior, a sliding Zahner zinc panel with machine-cut openings provides partial shade against the sun. Next, a layer of diffuse LEDs shines through the zinc screen, giving the house a glowing appearance in twilight. Both of these exterior panels can be set to slide in and out with the weather automatically. The house picks its settings via sensors embedded in its concrete floor. Behind the LED wall, a manually opened sliding door from Fleetwood separates indoors from out; riding in the track next to that is a robust sliding mesh screen. Inside the doors near the galley kitchen, a metallic curtain with a sun-reflecting coating automatically slides over the windows to reflect hot summer sunshine, or it retracts to allow solar heat gain during sunny winter days.

© Image by Harry Sawyers.

Most impressive about Virginia Tech’s plot on the mall, besides the sliding panel spectacle, was the extensive landscaping the school had done to dress up the site. Rookstool said that the team’s 2002 entry contained “about four potted juniper plants out front,” with little other embellishment. It’s quite a bit more elaborate this time around. “We didn’t want it to be a house sitting in the middle of nothing,” Rookstool said. “Otherwise, it just becomes a box.”

As students shoveled truckloads of gravel between plantings, fifth-year architecture student Travis Rookstool supervised a volunteer making a connection in the house’s passive grey water filtration system. Like its neighbors, Team California, Virginia Tech routes the water draining from the home’s kitchen sink and shower into the garden, where plants purify the waste water for use as irrigation elsewhere in the watery “yard.”

Nearby, a 1,000-gallon tank simulates a geothermal system Virginia Tech designed and built into the house, but was unable to implement due to drilling constraints on the Mall.

Maximum photovoltaic production under optimum conditions: 9-kW per hour.

Original source by Harry Sawyers.
From popularmechanics.com.