The UNC Charlotte team is calling their UrbanEden “a tree planted in the forest of the city.” The Solar Decathlon home is designed for Charlotte’s temperate climate and increasingly urban lifestyle and blurs the line between inside and out by creating a series of connected indoor and outdoor rooms. Smart material choices, such as highly insulated concrete panels and glass, combined with creative use of simple technologies, allow for light-bathed urban garden living that’s completely powered, heated, and even cooled by the sun. The open steel frame facilitates a visual and physical connection to the private garden to urge inhabitants to get outside and enjoy the favorable climate.
UrbanEden’s structural system consists of precast geopolymer concrete walls and floors and a post and beam steel frame that does double duty supporting both the building and the conceptual plan. Five double-wythe insulated precast panels make-up the north, east, and west walls of the house facing the street, while monolithic, insulated double-wythe concrete walls separate the interior from the street. Each precast wall panel consists of six inches of styrofoam insulation between two wythes of concrete. A carbon fiber mat embedded in each wythe and passing through the insulation structurally connects the three layers into a structural insulated panel (SIP). Though the PV array is the usual focus of attention, it’s the building envelope that makes solar power possible for this home. The high-performance envelope reduces heating and cooling loads and allows the photovoltaic system to be smaller and more affordable. UrbanEden’s envelope was also designed to minimize heat and water vapor movement through the construction, while maximizing heat storage capacity by placing considerable mass in the living space.
As the team notes: “An energy efficient building that doesn’t last is like a fast boat that doesn’t float. UrbanEden is built to last, accruing its energy savings over many years and therefore amplifying its positive effect.” Team Charlotte is sure to be a top contender this year.
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