Team Web site: www.uasolardecathlon.com
The Solar Decathlon qualifies as an ideal forum for experimenting with new technologies, materials, and systems. And that's just how the University of Arizona's 2009 Solar Decathlon team approached the competition, using it as a testing ground for many of the students' own research projects. The design of SEED [pod], as the house has been named, is based on the concept of achieving homeostasis (equilibrium) in the constantly changing environment of Arizona’s Sonoran desert. The students specifically engineered its many innovative systems to maintain environmental balance.
"We decided to create something that doesn't fight the climate, but works with it," explains Christopher Domin, associate professor and one of Team Arizona's principal investigators. The result is a site-adaptive house, with innovative systems specifically engineered by the students to achieve environmental balance for the SEED [pod].
Temperature, which can vary in the desert by at least 20 degrees between day and night, represented a major challenge and opportunity for Team Arizona. They found a solution through a series of cooperative systems. One graduate student designed a self-actuated shading system that responds to temperature changes by opening and closing folds of fabric that are attached to heat-reactive metal straps. The system works almost like human eyelids do, opening the fabric “eyes” to let light in through the window when temperatures are cooler, and closing the “eyes” when the mercury rises. (The team installed this system in one large SEED [pod] window.)
Along the house’s southern exposure, the team turned to a water wall, which absorbs the sun’s heat during the day and then releases that stored warmth into the home’s interior during the cooler nighttime. This too was designed by Team Arizona. Student Eddie Hall led the group in developing a vacuum-formed recyclable PET plastic "tank” sandwiched between two insulated glass windows with shades. During the day, that shade prevents heat gain inside the house from the water wall, while at night an exterior shade blocks the water wall’s heat from escaping and instead directs that warmth inside.
SEED [pod]'s framing system itself is a team-engineered innovation, constructed from laser-cut, bent, and folded sheet metal to form structural ribs. The house's structure is hinged along the bottom of the southern wall, allowing the roof to rotate and sit flat against the modular core for transportation. The roof pitch and the southern water wall can both be adjusted during construction to capitalize on a site's solar exposure. In addition, each v-shaped rib funnels rainwater to a collection tank.
With the hopes of increasing energy production, Team Arizona blanketed the home’s roof with Sanyo bi-facial PV panels, which capture light reflected by the house's white roof surface. An array of evacuated tubes also collects heat for the house's solar thermal water system.
According to fifth-year graduate architecture student Colleen Cummings, it's the interconnectedness of all of SEED [pod]'s systems that makes the house special. SEED [pod]'s structural rib framing system also supports the performance of the PV panels by creating a plenum space that allows air to move under the panels, cooling them and maximizing efficiency. Hot air is also exhausted from the building through the roof and under the panels to boost circulation while helping to maintain a balanced interior temperature.
But Team Arizona didn’t skimp on the interior appeal while as they designed SEED [pod]’s technological innovations. Warm wood paneling covers its one large loft-like living and sleeping space. The water wall filters light in ever-changing patterns while clerestory windows on the opposite wall flood the interior with brighter light. Sliding doors partition off the two sections of the bathroom from the sleeping area.
It adds up to a home that was clearly designed from a different perspective, both practically and visually. "I think [the Solar Decathlon competition] changes the way you think about building, the way you think about design," architecture student and Team Arizona member Cummings says. "I think it's going to make it unacceptable for me to work with a firm that doesn't support these sorts of ideals and goals."
Stephani Miller is associate web editor for residential architect and CUSTOM HOME magazines.