Academy of Further Education in Herne
Three months before the appointed opening of this complex, the world’s largest photovoltaic installation ever to be integrated in a building was connected to the electricity grid. The installation also serves as a means of sunscreening and daylight control.
One of the aims of the competition scheme was to create a large glazed hall with a cloud-like roof structure, the “microclimatic skin” of which was to be used to exploit passive solar energy. In the course of the planning, the idea of a photovoltaic installation was added to the concept. The cloud effect was to be created by varying the density of the solar modules. Over the buildings in the hall, the modules are laid out to a density of 86 per cent, thus providing the necessary sunscreening. To soften the contrast in brightness, the density was reduced to 58 per cent in the transitional zones. The central area of the roof was constructed without solar cells to ensure adequate daylighting in the spaces below. The numerous opening lights here also improve the indoor climate and the efficiency of the solar installation. The edge of the roof is lined with modular inverters, which convert solar current into 220 V alternating current. An artistic use of sunlight was achieved by incorporating holographic elements in the roof at certain points.
The protective “microclimatic skin” and the passive solar energy gains of the hall make it seem like an outdoor space in a mild climatic zone, thus reducing the energy needs of the buildings within it. The outer skins of these structures need be neither wind- nor waterproof and can be in a simple form of construction. The warm air that builds up beneath the roof can be used to reduce the amount of additional heating energy required in winter.
The load-bearing structure and the façade construction are in timber; i.e. a renewable raw material. The columns were constructed from 130-year-old fir stems.
A district generating plant uses firedamp from a former mine to produce electricity. The gas is more plentiful on dull days when the air pressure is low, so that the low solar energy yield under these conditions is balanced out. The academy thus represents a complex, holistic concept, both ecologically and socially.