Solar Decathlon 2009
The team's house is sized up to regulations and sports solar-collectors on every available surface. An 11.1-kilowatt photovoltaic (PV) system composed of 40 single-crystal silicon panels lines the roof, and the walls are covered with 250 thin-film copper indium gallium diselenide (CIGS) panels, which are less efficient than silicon but perform better in cloudy conditions. The house produces twice as much energy as it needs, which earned the team the highest possible score in the net metering competition.
The interior of the cubic two-story home is kept comfortable with custom vacuum insulation panels that line the facade, and with phase-change materials inside the drywall — paraffin in the walls and salt hydrate in the ceiling. Those phase-change materials absorb and release heat when transforming from solid to liquid and vice versa. They are excellent insulators because they can store and then disperse large amounts of energy.
Automated louvers over the windows block the heat of the sun, and the heat pump system incorporates a boiler for heating and cooling and water heating.
University of Illinois at Urbana-Champaign
Gable Home, the creation of the students from Illinois, who took second place overall, aimed to marry traditional homebuilding techniques with advanced technology. The team drew on the agricultural roots of the school's surroundings, designing a gabled house with barn-wood paneling, a barn-door-like sliding shade mechanism, and a deck made of wood from a grain elevator. The team won the contests for hot water, appliances, and home entertainment, and came in second in comfort, lighting design, and net metering.
Despite only half the peaked roof facing south, the solar panels generated up to 9.1 kilowatts of direct current power. Gable Home is so energy-efficient — using 90 percent less energy than an average house — that the solar panels produce four times the energy needed.
Tremendous energy savings accrue from the nearly 12 inches (30 centimeters) of high-performance insulation incorporated into the walls, roof, and floor; a high-efficiency HVAC system custom-made to meet the minimal needs of the small home; a hot water system heat exchanger; and LED lighting. The team expects that the structure will be certified by the U.S. Passive House Institute in Urbana, Illinois.
The team from California, combining the efforts of students from Santa Clara University and California College of the Arts, got third place overall, and took first in the architecture competition and second in engineering. Their offering, Refract House, was focused on linking interior and exterior spaces through the use of a J-shaped, window-focused design. Guests could use their phones to text a code or scan a barcode to learn about the home's features.
The house is designed like a bent paperclip, with sections of the structure wrapping around a central patio. This setup focuses the interior on south-facing vistas, which make the home seem larger. In the warm California summers, the patio can be incorporated into a spacious indoor-outdoor living space.
The house makes such good use of sunshine that it has almost no need for heating, and a solar thermal absorption chiller supplies radiant cooling panels and provides waste heat used to warm water for the solar hot water system. The roof carries an 8.1-kilowatt PV system in one unbroken plane.
Team Ontario/ British Columbia
One of two Canadian teams in the decathlon, Team Ontario/ BC came in fourth overall with a small home fit for northern climes. Unable to depend on rooftop solar panels year-round, the team of students from three institutions — University of Waterloo, Ryerson University, and Simon Fraser University — focused instead on lower-elevation solar collection by installing an 11.9-kilowatt system of floor-to-ceiling PV panels on the outer walls. The panels alternated with quadruple-glazed windows on the south, east, and west sides, contributing to the team's goal of creating a strong link between indoors and out.
North House makes ample use of advanced energy-efficiency technologies, such as evacuated-tube solar collectors connected to cascading warm-water storage, R-60 insulation, flooring insulated with salt hydrate phase-change material, and automated window louvers. A notable feature of the house is the computerized "living interface system" that allows residents to control their energy expenditure via desktop and mobile devices.
King, the event director, praised the 2009 entrants for their efforts. "These students learned the subject very well," he says. "They're going to go out and assimilate into industry with all this knowledge and all this know-how behind them. They're also pushing technology — there's a lot of innovation out here."
While only one team can go home the winner every two years, all the contestants benefit from taking on the challenges of the Solar Decathlon.
The primary sponsor of the Solar Decathlon is the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, with its National Renewable Energy Laboratory and private-sector sponsors: Applied Materials, BP, Pepco, and Schneider Electric, among others.
The panel of judges for the 2009 Solar Decathlon was organized by topic. Architecture: Kevin Burke, Jonathan Knowles, Sarah Susanka. Engineering: Richard Bourne, David Click, Ted Prythero. Market viability: James Ketter, Joyce Mason, Paul Waszink. Lighting design: Nancy Clanton, Ron Kurtz, Naomi Miller. Communications: Maureen McNulty, Jaime Van Mourik, Alan Wickstrom.
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Katherine Gustafson is a Washington, D.C.-based writer and editor who has also published in the Huffington Post, the Christian Science Monitor, and the Iowa Review, among many others. More by Katherine Gustafson