Open-Air Swimming Pool in Nördlingen

One of the main conditions of the brief was that the water for the pools should be heated exclusively by solar energy. This form of energy is ideally suited to this purpose, since a single sunny day is adequate to raise the temperature of the water for all the pools to the required level; and the number of visitors to open-air baths reaches its normal level only on the second fine day after a period of bad weather. The most striking feature of the design is the independent roof construction, which is slightly inclined to follow the slope of the site and to capture more solar radiation. The sections of the roof act as a series of large-scale umbrellas, beneath which the actual volumes of the building are inserted, with open passageways between them. Where functionally necessary, the buildings are joined to the roof with strips of glazing. Great importance was attached to the integration of the solar system in the roof. An absorbent surface 1,400 m2 in area and consisting of black, unglazed solar storage mats was installed in the industrial sheet metal roofing system. After treatment, the water is pumped into the storage mats, where it is heated by 5°–10° C and then fed into the circulation for the pools. On sunny days, the plant has a heating capacity of 850 kW. A photovoltaic system on the roof of the changing rooms converts sunlight into electrical energy. It has an area of approximately 60 m2 and a maximum capacity of 7 kW. The energy generated is fed into the electrical network of the baths.