Sunny prospects

Sunny prospects

Winning building by TU Darmstadt, Solar Decathlon 2009. Image: Stefano Paltera / US Department of Energy
Winning building by TU Darmstadt, Solar Decathlon 2009. Image: Stefano Paltera / US Department of Energy

The international 'Solar Decathlon', a competition held by the US Department of Energy in the capital Washington D.C., is the ultimate benchmark for students of architecture and their visions for living in the year 2020.

Every other year, student teams compete for the honour of having built the world's most sustainable and appealing solar house to date. To have a chance of winning, houses must be aesthetically pleasing, comfortable, and collect at least as much solar energy as its residents consume. A demanding jury of experts inspects every last corner of the energy-plus building to assess its performance. And in October 2009, for the second consecutive time, after eight days of field testing and nail-biting finals within a stone's throw of the US Capitol, the verdict was, “The winner is… Team Germany” – or to be more precise, just as two years before: “Technische Universität Darmstadt”.

A winning team

Interior view of TU Darmstadt’s solar house, 2009. Image: Thomas Ott
Interior view of TU Darmstadt’s solar house, 2009. Image: Thomas Ott

The Darmstadt 'power house', designed and built by 25 students from the Departments of Architecture and Electrical Engineering under Professor Manfred Hegger, demonstrates the outermost boundaries of the technically possible.

All four exterior facades are fitted with black reflecting shingles made of thin-film photovoltaic modules; the roof features crystal silicon solar cells. The solar-active, vacuum-insulated envelope of the building generates electricity for the entire house, from the heat pump and the LED light panels to the high-efficiency domestic appliances. The real show-stopper is the ultra-modern, smartly coordinated home technology, which residents operate intuitively via touch pad. In addition to the heat pump, a cooling ceiling and a sun-screening system ensure indoor comfort in every kind of weather. All systems are inter-connected, which enhances the building's energy efficiency.

This holistic concept was the major challenge: No participant could rely on their own contribution alone; all were responsible for overall success. The competition could only be won as a team. Right up until the last minute, students had to bundle their energy and knowledge to trump teams from Illinois and California who were slightly ahead of them. The deciding factor was the highly sophisticated and extremely efficient energy system of the house: Even in D.C.'s damp and chilly October weather, the electricity meter ticked in reverse.
And the story continues: By invitation of Solar Decathlon Europe, a team of TU Darmstadt architecture students built the world’s first energy-plus student hall of residence in Paris in 2014.