The Solar Decathlon Europe is not until 2014, but two European teams are competing stateside this year representing the Czech Republic and Austria.
Designed by students at the Czech Technical University, Air House targets not the typical young couples that constitute most first time homebuyers, but a demographic familiar to the students, their parents—the 50+ empty nesters. The team cites data that states that senior housing represents 20% of Czech households and that number is growing. Conceptualized as weekend country house, it transitions to a permanent residence as the owners retire.
Air House’s layout is straightforward: an independent L-shaped structure shrouded in a wood canopy and façade. The team calls it a “house within a house”, with the main living space is located long leg of the L. Unlike many of the entries, the Czech team’s interior is a single loft-like space, with a sliding door that opens directly onto the outdoor living room. Built-ins on the south side are beautiful detailed in unfinished birch, however the wall is chock-full of insulation. The short leg houses the bathroom and equipment for the radiant chilled ceiling system, rooftop solar panels, and the graywater collection system (to serve the house’s constructed wetlands).
LISI from Team Austria brings together students from Vienna University of Technology, St. Poelten University of Applied Sciences, Salzberg University of Applied Sciences, and the Austrian Institute of Technology. The house, not unlike SCI-Arc/Caltech’s DALE, surprisingly blurs the line between inside and outside. Large retractable sliding glass doors on the north and south sides disappear into the core areas leaving the living open to the elements, more like a covered courtyard than an interior. Lightweight curtains wrap the house for privacy and extra shade when low sun angles are at their most intense.
One student confessed that the glass doors, by the manufacturer Josko, were one of the most expensive parts of the construction. But considering how integral they are to the project, they seem worth it. They also point to two differences between the two European projects and some of the North American entries. First, the Czech and Austrian teams maximized single living areas and minimized auxiliary rooms, which streamlines passive heating and natural ventilation. (There’s a tiny, cave-like bedroom in LISI.) Second, heating, not cooling, is a larger pressing concern for energy use. Info graphics produced by the Austria team put numbers to this fact. Heating demands in Vienna are 9.7 kWh/m2 per year and cooling is 5.6 kWh/m2 per year. In Irvine, ostensibly a nicer climate year-round, the loads are actually higher due to cooling requirements; heating is 2.7 kWh/m2 per year and cooling is 10.6 kWh/m2 per year.
Or as Team Austria’s Philipp Klebert, a mechanical engineering student at Vienna UT, puts it: “In Austria, when we design passive houses for comfort, it is more about the heating. For most of us, this was our first time in Irvine and in the U.S.. We had to get used to the weather.”>