University of Tennessee’s Living Light is among the 2011 Solar Decathlon’s more straightforward expressions of form and function, with heavily glazed north and south walls and a compact, steel-framed rectangular shape that allows it to be lifted onto a set of truck-trailer wheels, coupled to a road tractor, and hauled down the highway like a moving van.

In designing Living Light, its first Decathlon entry, Team Tennessee said it was inspired by Cherokee shelters in East Tennessee and the cantilevered barns of Appalachia, where both winter and summer include challenging weather conditions. But the team also focused on how the home’s simple shape could be exploited to make the most of its passive solar and daylighting potential.

The house is 750 sq. ft. – notably smaller than most homes in the 2011 competition, where the limit on interior space is 1,000 sq. ft. The east and west ends, which contain the mechanical cores, feature R-30 stud walls. The 10.9-kW rooftop array is horizontal, and the white reflective roof under it is nearly so. The array, in this case, uses a copper indium gallium diselenide thin-film absorber wrapped inside cylindrical modules to capture sunlight from all directions.

Clear, translucent, and layered walls

Living Light’s north and south walls are layered with glazing in unconventional ways. Each wall is actually a double façade: on the outside, a single fixed pane of tempered R-1 glass sits on shock-absorbing mounts; on the inside, R-11.4 triple-pane windows, some of which are operable, sit in wood-veneered aluminum frames. Transparent glass dominates the south façade while translucent glass dominates the north façade, although the operable-window areas on each will be about the same.

One basic aim is to provide abundant daylighting for the structure and maximize passive solar gain when it’s needed in the winter. But the walls actually are as much about shading as they are about flooding the house with light. An automated, horizontal-blind system sandwiched between the inner and outer glass walls controls the amount of light let into the conditioned space. And as the blind slats warm up in the sun, a ventilation fan directs air to an energy-recovery ventilator to harvest the heat. The space between the inner and outer windows also is equipped with hidden electric lights whose automated operation is coordinated with that of the blinds to smooth transitions from daytime to night and back.

In addition to the energy-recovery ventilator, the HVAC system includes two ductless minisplit heat pumps. Team Tennessee says the house is designed for “young professionals with an average income of $100,000 working in the vibrant design, science, and technology industries of Nashville, Tennessee.” But after the Decathlon, it will hit the road rather than the real estate market, embarking on what the team had dubbed the Tennessee Tour. After that, it will serve as a laboratory for new technologies and collecting performance data.