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January 11, 2010

The Solar Decathlon: Housing's Bright Spot


Teams design and build homes powered by the sun

This past October, taking a walk on the National Mall in Washington, D.C., might have been more like taking a walk into the future. Twenty solar-powered homes were sprawled across the mall's west end, transforming it from a park into something that resembled an innovative new housing development. Park purists take note: the transformation was only temporary. The homes were part of a competition.

"The Solar Decathlon is a competition for university schools of engineering and architecture to design, from the ground up, a solar-powered, high efficiency, self-sustaining house," says Solar Decathlon Director Richard King.

This was the fourth contest since 2002 and it is estimated that, over the years, more than 10,000 students have participated in the Solar Decathlon. This particular competition drew 20 teams from as far away as Spain and Germany. This is where mind meets muscle because the challenge is to both design and construct a "zero energy" home, meaning a home that produces as much solar energy as it consumes.

Factors for judging

"The decathlon gets its name from ten contests; so, we judge them for architecture, engineering excellence, market viability, communications, and lighting and interior design," explains King. Additional contests include heating and cooling, appliances, and even home entertainment.

"People have video games and Wii ® [consoles], home theater systems, a couple computers going and it really eats up energy," says King. This year, they added a net metering contest to the competition. It measures energy production and use, and teams get points if they produce more energy than they use.

Preparation for this competition started two years ago. Any group of students hoping to compete must submit it's proposal to a committee of architectural and engineering professionals for approval. With only 20 slots available, the selection process is tough. If selected, the teams are provided grants of $100,000 from the U.S. Department of Energy to go toward building, constructing and transporting the house. The $100,000 grant will not completely cover those costs, so teams are expected to find the rest of the funding elsewhere. They must apply for other grants, seek sponsorships or both.

Getting there

Once the home is constructed at a team's location, it must be disassembled and transported to Washington, D.C. That poses a lot of challenges, which Joe Rice, a decathlete from the University of Wisconsin-Milwaukee, knows all too well. "We were three inches too tall to drive through the state of Indiana so we had to drive all the way down around Illinois and back up through Ohio."

Despite Team UW-Milwaukee's transportation challenges, team members touted their home's carbon neutrality. All the wood in the home is from Wisconsin. "Through use of local materials and our solar array, we can get as close as we possibly can, excluding shipping," notes Rice.

Rice's journey from Wisconsin seems almost quaint after talking to Patrick Tauchert of Team Germany. The home's fašade was comprised of solar cells made mostly of glass. The entire process of shipping it over 4,000 miles from the Technical University at Darmstadt took nearly a month.

"In Germany, the roads are even smaller than in the United States, so it was quite a tough thing to create a house that is built in modules that can be transported on German roads," explains Tauchert. The trip also included an eight-day transatlantic ride on a ship. "I was really scared, but when we arrived in Norfolk and opened the package, everything was good and there was no broken glass at all."

Team Germany had a lot at stake coming into the contest. They were the defending champions from the last Solar Decathlon held in 2007. Since their house is covered by solar cells, they were hoping to produce twice the energy needed to keep the house running during the contest.

Innovations abound

Team Spain's slogan was "follow the sun," and they lived up to it! "We have a unique roof. It's a sun tracker in fact, so it pivots along the day following the sun," says Team Spain decathlete Irene Garrido. The Universidad PolitÚcnica de Madrid has filed for a patent for the system that makes the roof pivot and accurately track the sun.

Some of the teams were made up of students from a number of universities in a given area. For example, Team Boston was comprised of students from the Boston Architectural College and Tufts University. Together, the students designed a special gel that rests between panes of glass.

Stephen Messinger, an architecture student who says he likes to use thoughtful designs to improve the planet, explains how the window system works. "Sunlight gets absorbed by a gel layer that's in the middle of the system and then, over the course of a night, that solar energy slowly radiates into the house. It's 100 percent passive and can do 80 percent to 90 percent of the heating of your house."

Creativity is an important part of the contest as well. Cornell University team members wanted their home to somehow aesthetically represent the area around Ithaca, N.Y., so they created three cylindrical modules to reflect the shape of the grain silos that dot the rolling hills of upstate New York.

And the winner is...

The 2009 Solar Decathlon lasted nearly two weeks and received more than 300,000 house visits. A member from the University of Puerto Rico's team, Mariela Lugo, thinks that kind of turnout says something about the draw of solar power technology. "It demonstrates the interest of the public to see and know that you can do it in your own home."

Amid cheering and the music of the Black Eyed Peas' "I Got a Feeling," the announcement was made that, for the second time in a row, Team Germany took first place and defended their title as the Solar Decathlon champs. But the hope is that the efforts of all the teams will help the public better understand how the power of the sun can make the future a little brighter. The next contest is in 2011.

Miles O'Brien, Science Nation Correspondent
Jon Baime , Science Nation Producer


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