Solar architecture Solar decathlon europe Exciting but exhausting The first Solar Decathlon Europe took place in Madrid in Spain, France, Germany, England, Finland, China, and the US envision the future of energy-efficient June. In the solar architecture competition, 17 university con struction. With their zero-energy houses, they qualified for teams from three continents presented their vision of a the first-ever Solar Decathlon Europe (SDE), a solar zero-energy house. architecture competition for universities, which took place for the first time in the Spanish capital. In a he contrast could scarcely have been greater. neck and neck race, the American team from Virginia In the background, to the west of the Manzana- Polytechnic Institute & State University won the com- Tres River in Madrid, high-rises jutted skyward petition with its Lumenhaus, followed closely by two as they do in rapidly growing cities – functional but German teams. not exactly aesthetic. Nondescript energy guzzlers. On the opposite side of the river in late June, 17 Born in the USA houses overlooking the royal palace offer a counter- point to the high-rises with individualism and innova- The Solar Decathlon Europe is the progeny of the tion – a Chinese bamboo house with curved roofs, Solar Decathlon, held for the first time at the National compact bungalows with white, black, green or blue Mall in Washington D.C. in 2002. The competition has façades made of glass, wood, or plastic; a wooden been held biennially on the same spot since 2005. house on four legs and a shimmering metallic abode While university teams from around the globe are in- in the style of a container. Photovoltaic modules and vited to participate, most of the teams were from the solar collectors are on many of the roofs and façades. US. Until 2007, the US Department of Energy, which The structures show how 17 university teams from organises the competition, called for an off-grid, The Bamboo House of the energy-autonomous house. Since 2009, a net zero- Tongji University Shang- energy house with a balanced annual energy budget hai uses traditional lines is required. and modern technology. Photos (7): SDE The competition is not concerned with which house has the best energy concept. Interdisciplinary expert juries examine the houses in ten categories; hence the name, decathlon. Up to 1,000 points are awarded, based on subjective jury decisions and ob- jective measurements. The categories are: architec- ture, engineering and construction, solar systems, electrical energy balance, comfort conditions, appli- ances, communications and social awareness, indus- trialization and market viability, innovation and sus- tainability. To make them comparable, the houses may not have more than 75 m² of living space and are limited to a height of 5.5 m. First place in the Solar The Universidad Politécnica de Madrid (UPM), chitecture student and assistant juror Roberto Steck- Decathlon Europe went to the which participated in the Washington event in 2005, Ibarren. The following houses show the broad spec- Virginia Polytechnic Institute 2007 and 2009 drummed up interest in holding such trum of construction and energy concepts, as well as & State University team for its an event in Europe as well. In cooperation with the the wealth of the students’ ideas. Lumenhaus. Spanish Ministry of Housing and with the support of The only thing all of the houses shared in com- the US Department of Energy, the plan became a mon was the optimised thermal insulation, which the reality. The criteria for the US competition were adopt- teams achieved through very well insulated building ed for the most part. envelopes (at least 30 cm thick walls) and excellent solar shading. Many of the teams used passive ele- It takes steady nerves ments, such as phase change material (PCM) for inte- rior tempering. But none of the houses in Madrid The students from fields such as architecture, interior could completely do away with active systems. In the design, engineering, structural engineering, sustain- hot, dry climate of the Spanish metropolis, cooling ability, and energy systems worked on their projects stood in the foreground. Ventilation systems with for an average of two years. They waded arduously heat recovery and reversible heat pumps were often through 300 pages of performance test codes and used to achieve comfortable indoor temperatures. formulated 500 page project reports. They sought The competition rules required the houses to main- sponsors, negotiated with manufacturers, and built tain room temperatures no greater than 25°C. furniture, façades, and shading systems. They draft- ed communication concepts and brochures, then or- The Lumenhaus from Virginia ganised the transport of the houses to Madrid. Once in Madrid, they built their prototypes at lightning “If it gets too hot outside, the house reduces the need speed and presented them to the interested public for air conditioning by drawing its shade panels. for ten days in the blazing heat. When temperatures drop in winter, high-efficiency in- And, while the event did not attract as many visi- sulation panels slide in place to conserve heat.” That tors as the Solar Decathlon 2009 in Washington – is how the team from Virginia described the advan- some 300,000 over ten days – still, tages of its Lumenhaus. The name comes from lumen, organizers say that some 190,000 meaning “power of light”, and haus, a nod to the visitors turned out at the Villa Bauhaus architecture movement which inspired the Solar to size up the houses and prototype. All of the building services systems can be ply the students with ques- controlled via Apple’s new iPad tablet PC. The inter- tions. “Every house has some- face can also communicate with a weather station set thing unique,” points out ar- up in front of the house. Easy to transport. The house arrived at its loca- tion on four wheels, which were easily removed once it was in the correct spot. It can be taken away just as easily. Virginia Polytechnic Institute & State Univer- sity achieved first place in the competition with 811.83 points. The university had already participat- ed in the Solar Decathlon in Washington in 2009. Meanwhile, the team had “modified some systems,” according to architecture student Travis Rookstool. German team right on the heels That made it all the more satisfying for the team from the Rosenheim University of Applied Sciences which like the other 15 teams took part in the Solar Decathlon for the first time. The 30 members of team Sun & Wind Energy 8/2010 49 Solar architecture Solar decathlon europe The entry from Florida (left) was distinctive for its breeze- Rosenheim finished an extremely close second with thermal bridges. The Finns generate power with 60 m² way, which provides natural 810.96 points. Right on their heels with 807.49 of monocrystalline PV modules on the roof; they in- ventilation for the house. points, was the Stuttgart University of Applied stalled 5 m² of flat plate collectors to cover heating. The Finns (right) emphasised Sciences. In addition to these two teams, two other While Auvray was disappointed that the team did not sustainability, using only German teams participated, one from the Bergische take first place in the sustainability category, he said natural materials. Universität Wuppertal (6th place) and one from the that he was nonetheless proud that it was Finland’s Hochschule für Technik und Wirtschaft Berlin (10th first net zero energy house. place). Even though they entered separately, the four The Tongji University team from Shanghai also teams were often referred to as “Team Germany.” used typical Chinese building material – namely, What their prototypes demonstrated in particular bamboo. “It is a traditional Chinese residential house was the diverse range of possible façade types. The with the double-curved roof and the bamboo inside team from Rosenheim developed a privacy and sun and outside,” says team member Jiawei Wu. Vacuum shade made of white aluminium. Installed on the ex- insulation panels were used for insulation. The stu- terior walls, the system can be raised from the ground dents mixed PCM into the concrete-like wall material level as needed. While the Rosenheim students con- in order to keep the room temperature stable. PCM is cealed their 12.6 kW of PV behind a slightly elevated also integrated into the floor of the bedroom, allow- exterior wall, the team from Stuttgart decided to inte- ing residents to get by without ventilation. The Chi- grate some of their modules into the façade. nese installed bamboo mats on the exterior. Active Maximilian Martin, now a graduate, who worked on systems included a 9 kW system with modules pro- the project from the very beginning, explains, “We vided by Chinese manufacturer ENN and tube collec- wanted to use the photovoltaics not only as a techni- tors for hot water. cal element, but as a design element as well.” Like the house from China, the University of The students from Wuppertal also installed PV Florida building was built in a style typical of its coun- modules on the south-facing façade surfaces. Their try of origin. The students modelled their entry on so- entry stood out for the gray envelope covering the en- called “cracker houses.” This typically Florida-style tire house. The aluminium-coated awning fabric of- construction is tailored to the hot, humid climate in fers a high degree of shading, while at the same time the American state. The characteristic feature is the offering a view to the outside. The Berlin team’s breezeway, a corridor between the night area with house, called Living Equia, attracted attention with bedrooms and bath, and the living area with the its black façade.