Solar Cells Info

By Gerry Shih, February 19, 2008
Source: The Statesman.com
http://www.statesman.com/blogs/content/shared-blogs/washington/washington/
entries/2008/02/19/officials_highl.html

By all accounts, the 2007 Solar Decathlon resembled a modern auto show – the hype around energy efficiency, the glimpses of future technology, the deja vu as German engineering upstages the American effort.   But while their automobile counterparts fret, American green tech engineers believe there are fortunes to be made in everything ranging from low-energy heating and cooling appliances to heat-efficient materials to whole modular homes that are starting to hit the market. On Tuesday, the director of the decathlon recapped some highlights of the competition, where twenty universities one-upped each other with fascinating feats of innovation.

The twenty universities from around the world, including four contenders from Germany, Spain, Canada and Puerto Rico, built green-friendly, solar-powered houses that were judged while on display on the National Mall toward the end of last year.

These genuinely attractive and liveable homes (given the addition of plumbing and other services like cable and Internet, perhaps, that were unavailable on the Mall lawn) ranged from about 500 to 800 square feet and were completely self-reliant in energy use.

Here’s a shot of the houses, and the some of the estimated 100,000 visitors who showed up over a one-week period to take a peek.
https://www.eere-pmc.energy.gov/SolarDecathlon07/images/10-12/1553450787.jpg

Germany’s Darmstadt Polytechnic barely edged out the University of Maryland in last year’s contest to nab first place after being judged along ten criteria, including architecture, engineering, market viability, hot water and appliances.  Richard King, the Department of Energy official who directed the decathlon, noted that although the aim of the competition was to use readily available commercial supplies, “some of these innovative products were invented or built for the first time on campus.”

Some highlights:
* The Darmstadt team used “phase changing” material that made their walls hold heat like a giant stone wall.
* The University of Maryland team created a waterfall of liquid calcium chloride (a highly absorptive salt that wicks humidity out of the air) to combat humidity
* The Georgia Tech team made windows out of exotic ethylene tetrafluoroethylene, a “miracle” translucent material that is 1 percent the weight of glass but bears 400 times its weight, transmits more light and insulates more heat.
* Santa Clara University put used blue denim to good use as insulation in the walls.

In these competitions, efficiently using generated power is key. Solar energy, usually collected by roof-mounted solar panels, is converted and stored in battery packs then used for a variety of purposes (one element of the competition is charging an electric car with leftover energy). King said the local energy company will provide an independent grid next year for competitors to use instead of dangerous battery packs.

Most of the homes were stylishly furnished with colorful modern furniture but barebones regarding appliances that use electricity or heat. Hot water is a valuable resource, and as some teams demonstrated, can be run beneath floorboards for heating, for showers and sinks, and even cooling.  But the UT-Austin team distinguished between responsible conservation and overzealous skimping — they threw in a hot tub on the back deck.