Photos: Techstyle Haus © Domaine de Boisbuchet, photo Julia Hasse 2015
Techstyle Haus, Lessac, France The challenge for this project’s designers was daunting: create a highly efficient solar-powered house from scratch, build it with materials that have never been used before in residential construction, then get the whole thing to France for an international competition. Techstyle Haus is a self-sustaining solar home built by students from Rhode Island School of Design, Brown University and University of Applied Sciences Erfurt in Germany for the 2014 Solar Decathlon Europe. The competition challenged 20 university teams from all over the world to build efficient, comfortable and sustainable solar homes.
Techstyle Haus’s gracefully curved exterior shell is made from a flexible textile material supported by steel structural ribs. The material, Sheerfill II architectural membrane (a fibreglass membrane coated in teflon), is generally used on the roofs of domed sports stadiums and airplane hangers, but has apparently never before been used in residential construction. The textile walls were insulated with mineral wool, and also feature Isover Vario vapour membranes and Saint-Gobain triple-glazed windows. When the outside temperature rises, phasechange materials in the house’s mechanical core change from solid to liquid, trapping unwanted heat in the process. When the temperature cools, the materials solidify, releasing that trapped heat to keep the house warm.
The house features air-to-water Viessmann and Daikin heat pumps for heating and cooling, Viessmann heat recovery ventilation, 24 square metres of electricity-producing solar PV and six square metres of solar thermal collectors for hot water. Meanwhile, greywater from sinks, showers and appliances is filtered and recycled to irrigate the gardens outside. Techstyle Haus finished third in the ‘comfort conditions’ category of the Solar Decathlon, and came 14th overall. Built to the passive house standard, it hits key targets for space heating demand (13.3 kWh/m2/yr) and airtightness (0.6 air changes per hour). The building now provides student accommodation at Domaine de Boisbuchet, a centre of art, architecture and design in west central France. u