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Weser Stadium in Bremen merges design and ecology
The virtuous versatility of the Makrolon® sheets from Bayer Sheet Europe was impressively demonstrated once more in the renovation of the Weser Stadium in Bremen, Germany. The building has set new standards for sports, architecture, and energy technology. It is the only sports venue in Germany that integrates a photovoltaic installation into the building design in order to generate energy in an environmentally friendly way. The roofing made of Makrolon®, the polycarbonate from Bayer MaterialScience, fits harmoniously into the roof design. In a few weeks, the second construction phase will start, creating an additional 770 m2 of roof with the transparent Makrolon® photovoltaic (PV) modules (manufactured by Sunovation GmbH in Elsenfeld, Germany).
1,500 m2 of the new roofing were already installed in 2009, using the innovative solar modules. The silicon cells, which are floating between two Makrolon® sheets, generate roughly 100 watts of electricity per square meter. The modules, which feature a special combination of functionality, creativity, and design, won the "Product of the year 2009" award of pro-K, the German Industrial Association for Semi- Finished Products and Consumer Products.
In Bremen, the solar modules are not just installed on the roof but they are fully integrated into the roofing. This makes the Makrolon® roof fit harmoniously into the architectural design, providing protection from wind and the elements. The distance between the cells is variable, and the use of partially transparent solar cells is also possible, which makes the modules highly translucent. Good translucency is especially important for healthy turf growth on the athletic field. The solar cells are bonded with a special technology that ensures a long life of the modules even for curved shapes. Tests on the scale 1:1 in real conditions demonstrated that the modules also comply with the fire protection requirements for the construction sector.
The company Hans Börner GmbH & CO KG in Nauheim, Germany, which was commissioned with the planning and installation of the roof, found that another advantage of the polycarbonate sheets is their low weight. The 3.5 m2 modules weigh 10.5 kg/m2, which is 60% less than glass. In sophisticated architectural designs, as in the case of the large overhanging roof of the Weser Stadium in Bremen, Makrolon® modules are often the only possible solution.
The modular structure - a sandwich-combination of solid sheets, three-wall sheets, and the interior floating silicon cells - created additional strengthening benefits, as the roof supports mechanical loads well. The 4-mm solid Makrolon® sheets are break-resistant and bendable. The sandwich-like structure provides the sensitive silicone cells with the best possible protection. The supporting bottom layer consists of 16-mm Makrolon® 3-wall sheet designed for maximum load transfer. And, last but not least, the thickness and the shape of the sheets have been tailored to the local conditions of the stadium in Bremen, which guarantees the modules a long life.