For nine days in October, the National Mall in Washington, D.C., became a solar village of 20 energy-efficient homes for the U.S. Department of Energy's (DOE) third Solar Decathlon. The competition has teams from colleges and universities around the world design, finance, construct, and operate homes that are powered entirely by the sun. Teams submit proposals to the Solar Decathlon Proposal Review Committee, which selected this year's participants from a total of 30 proposals. (The 2009 request for proposals is available at www.solardecathlon.org.) The DOE funds teams with $100,000 each over a two-year period, however, this amount is not enough to cover all expenses and teams are required to outline additional fundraising plans in their proposals.
The decathlon, which is open to the public and had more than 100,000 visitors this year, includes 10 contests that relate to ways we use energy in our daily lives: architecture, engineering, market viability (whether the house has market appeal to the target audience chosen by each team), communications, comfort zone (to maintain a steady, comfortable temperature and humidity throughout the house), appliances, hot water (to supply the daily amount of hot water used by the average household), lighting, energy balance, and getting around (putting miles on an electric vehicle powered by the home's solar electric system). Scores from each contest are totaled, resulting in the overall winners of the competition--this year's top three were Germany's Technische Universitat Darmstadt, the University of Maryland, and Santa Clara University (SCU).
Some of the contests have juries to help determine the winner, the lighting contest among them. This year's lighting jury was composed of three professional lighting designers: Nancy Clanton, founder and president of Boulder, Colorado-based Clanton & Associates; Naomi Miller, principal of Troy, New York-based Naomi Miller Lighting Design; and Sandra Stashik, principal at Philadelphia-based Grenald Waldron Associates. They awarded 75 of the total 100 points in the lighting contest--50 points for electric lighting quality and 25 points for daylight quality. The remaining 25 points were determined by illuminance measurements taken at each home. While Maryland, Darmstadt, and Team Montreal (made up of students from Ecole de Technologie Superieure, Universite de Montreal, and McGill University) took the top three spots, respectively, in the eyes of the jury, once the points from the illuminance measurements were added, the overall lighting contest results put Darmstadt in first, Maryland in second, and Penn State in third.
With only a half hour to spend in each house during the day and 10 minutes at night, the jurors had a whirlwind day of judging. But despite the short time frame, Clanton, Miller, and Stashik did not have trouble coming to a consensus. "It was kind of surprising that although we all had different backgrounds, we all had very similar tastes in both daylighting and electric lighting," Miller says.
Students from each house had only 25 minutes total to explain their lighting design to the jury. "You could tell the schools that have lighting programs--the students really had all the right lingo [and] could talk about luminances and daylight. They really got it," Clanton says.
When judging daylight techniques, all three jurors were looking for views from the homes, in addition to sunlight that was pleasant and diffused in some way. "We wanted to make sure that there were no places where sun pouring in could really be uncomfortable," Miller explains. "We were looking for enough daylight in most spaces so you didn't need to turn on lights during the day."
Darmstadt used movable timber shutters equipped with photovoltaic cells on the outermost layer of the home to support energy supply while also controlling direct sunlight. The jurors found Darmstadt to have good views from its home in addition to a grasp on the concept of sun control thanks to the louvers.
Montreal, whose home Lumen|Essence had kiln-baked birch wood on the east, west, and north exteriors, took advantage of its location on the National Mall with "spectacular views," in Miller's words, of the Washington Monument from one end of the house and the U.S. Capitol from the other. Maryland also had great views, Clanton points out--the best being from the bathroom, a space where many of the teams did not incorporate daylight.
Maryland's LEAFHouse "beautifully integrated the daylight" and was the top choice of the jury in that regard, Miller says. John Kucia, a Maryland team leader who worked on the lighting design, says much attention was given to daylight, with electric light coming into play later (see image gallery). A translucent polycarbonate roof-ridge skylight system maximized natural light entering the house.
Montreal's architectural design was influenced by daylighting from the start. Team member Libby Dror, who helped with the lighting design, says the team actually changed its original house design to allow for more daylight.
On the other hand, Brian Drocco, the lighting designer for SCU, says his focus was electric lighting. "My primary goal was to make lighting in our house very functional," he says. Many fixtures used fluorescent lamps and could be dimmed. Although SCU had some great ideas, Stashik says its lighting score suffered because "they had a mix of too many different kinds of fixtures in the space."
While a variety of too many luminaires may have taken points away from SCU, the jurors said almost every home missed the mark on accent lighting. "They didn't realize just one table lamp would have done it and balanced things out," Clanton says. Miller expands on that, pointing out the need to bring light down to the work plane--and how doing so can make the space more intimate.
Another aspect many teams did not address was the lighting of vertical surfaces, the jurors say. "Most of them seemed to understand that you need to light the ceilings [by using] indirect lighting," Clanton says. "But then some excitement or lighting on a picture or wall was really lacking."