Part 2: Solar flexes its muscles at Decathlon

Dec. 1, 2007
Washington We began our coverage of the Solar Decathlon and several of the colleges and universities competing in the biennial competition last month (November, p. 20). As promised, here's Part 2. In third place, Santa Clara University was a late entry and jumped in when another team dropped out of competition ( At just 630-sq. ft., I expected SCU's house to cramped. The opposite

Washington — We began our coverage of the Solar Decathlon and several of the colleges and universities competing in the biennial competition last month (November, p. 20). As promised, here's Part 2.

In third place, Santa Clara University was a late entry and jumped in when another team dropped out of competition ( At just 630-sq. ft., I expected SCU's house to “feel” cramped. The opposite was true — the open construction and expansive porch that blended seamlessly into the home's open doorway made this home feel palatial!

One of several innovations centered on bamboo structural ceiling-beams that were engineered to support 10,300-lbs. each — a modern construction “green” innovation never before seen and their look was too good to cover up with something mundane, like drywall or plaster. Pull-down kitchen cabinet shelves drew “oohs” and “aahs” from the gathered crowd. Electro-chromatic windows that could be made opaque with the flip of a switch — for privacy that allows light to enter, but not prying eyes — gained immediate approval. Hidden indoor air sensors that controlled all mechanical functions ensured comfort would be maintained invisibly and silently. Bathroom walls shimmered in recycled glass from, of all things, Coke bottles!

But the one thing that really grabbed my attention: an absorption chiller system that was so out-there, it had never before seen any public exposure! So new in fact, that the manufacturer had yet to make it available to the general public because of the need to develop controls suitable for mass production. Santa-Clara's innovative efforts in designing controls have broken down the barrier — their designs will be utilized to produce controls for the absorption chiller units that will be mass-marketed.

We met Evan Sarkisian, a philosophy major, on the back porch. How, I wondered, did a philosophy major end up on a Solar Decathlon team? Turns out he was an engineering student and had begun helping on this project. While doing research at the college library on philosophy, he realized there was a connection and decided to explore this field of study in more depth. He'd worked with his father for years in the family's machine-shop, so he was handy with the mechanics, too, but it was Dad who encouraged him to “go for it” — he switched majors.

Look for Sarkisian's explanation of the absorption chiller on the SCU Website.

We covered the second place finisher, the University of Maryland, last month. Please see, however, my story in this issue on how I and Dan Foley helped them out with their punctured radiant floor tubing (p. 5).

At day's end, we secured an entry into the first place finisher, Technische Universität Darmstadt, Germany's solar house ( We'd been drawn in by the louvered PV panels doubling as sun-screen-porch-panels. Holger Wagner was responsible for these uniquely-designed one-of-a-kind louvered-panels and revealed how they worked in great detail. Each of the louvers holds one mini-PV panel. Each mini-PV panel is split into two separate PV panels and each one has a “back-current diode” that acts much like a one-way valve. Electrons excited by the sun's energy can exit to contribute to the PV-power, but they can't return.

So why does this matter I asked? Instead of treating me like a dummkopf, Wagner carefully explained why: “You see this shadow you are casting on the panels? Your shadow halts electricity production and, absent the back-current diodes, the power generated by the other panels seeing full sun would rush inward and ruin the PV circuits in the shaded panel.”

Darmstadt's back porch was very inviting. Its roof consisted of horizontally placed PV panels that acted like a pergola — providing partial shade and perfect function. The students here also chose to keep their rooftop PV panels flat because of the minimal loss of solar harvesting.

“In Germany, we have excellent government/utility cooperation,” they said. “We pay approximately 49-cents per kWh to purchase grid-power-generated electricity, but we are paid 70-cents for every kWh we produce and send to the grid. As a result, Germany is currently the world leader in PV solar installations.”

OK, I'm officially jealous! In fact, I think I was drooling.

But don't think Darmstadt had it any easier than their American counterparts! Shipping and customs nightmares equaled lost sleep and last-minute panic-mode glitches that seemed insurmountable. No one, it seems, gets through the Solar Decathlon unscathed. In the grand scope of things, that may just be for the best. Without adversity, there can be no real victory!

Common threads that ran through the exhibits: mini-split inverter heat pumps for back-up heating and the cooling/dehumidification needs; energy recovery ventilators; solar thermal with storage for both domestic potable water and hydronics with physical separation between the two fluids; scald-guard thermostatic mixing valves to protect humans interacting with potable hot water; radiant hydronic systems with assorted pumps/controls; hybrid lighting systems with automation; low-consumption plumbing fixtures, gray-water recycling and agriculture uses integrated to mesh with potable water recycling; rain water reclamation and reuse; innovative outside-the-box use of materials to harvest, or reject, the sun's energy at every twist and turn; and hordes of bright, cheerful, enthusiastic students about to embark on life's greatest journey while striving to make a difference and improve our lot in life. Our future is both bright and secure in the hands of this generation as they seek to put their indelible mark on society.

Each team will be fondly remembered and there are no losers in this contest. Austin's wood-fired combination hot-tub/hydronic heat source/stir-fry cooker lives on in my memory. Colorado's copper curtain-wall and unique thermal storage; Madrid's sliding solar panels with guide Yanaria Demay's radiant smiles leading the way; Cincinnati's great rear porch; Puerto Rico's Katiyana Martinez's organic gardening and hydroponic tour; Texas A&M's greenhouses using bat dung collected from their on-site bat house — the ultimate in recycling! And their all-too-cool-looking front porch water-gardens, wind turbines and array of vacuum tubes; Missouri-Rolla's Watts Radiant wall panel purring like a kitten and Adam Smith's mangled hand — he darn near sacrificed it to the effort; the Kansas “wall” of evacuated solar tubes — that rocked!; Cornell's gardens and racked solar support system; Georgia Institute's home that glowed at night through its translucent walls; Massachusetts Institute of Technology — technology and flexibility all rolled into one; Team Montreal's very attractive home — c'est magnifique!; University of Illinois at Urbana-Champaign's modular design — spectacular simplicity; Lawrence Technological University had two bedrooms, a flying pergola (stunning element) and outstanding gardens; while New York's Institute of Technology incorporated a roof pond.

For more on the 2007 Solar Decathlon, its rules and 10 areas of judging, please visit

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Dave Yates

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