180 flats with the sunny heat

Alternative, low-priced energy will determine the future, even in branches like construction of new buildings. In 1998, the Hanseatic City of Rostock already prohibited the use of solid or liquid combustibles for heating fiats. What could become more obvious for sunny Mecklenburg-Vor Pommern than the production of heat in order to provide the service water? Undoubtedly, the use of the power of the sun. "WIRO-Wohnen in Rostock" Ltd. realised the dream of the city creating a new buildings in 2000. The annual need of heat is supplied up to the half by solar or geothermal energy. 108 fiats with a living area of 53 to 93 m² were built in the form of apartment buildings. The three-fioor houses were constructed in north and south direction and consist of traditional masonry with an increased amount of insulation. Several materials were assembled of long-lasting and low-maintenance building materials. The green roof terraces keep the dust emission low, implying a better climate for the whole building and its environment. An aeration system intensifies the exchange of air with speed of 50 m³/h.

At once the external design of the housing area catches one's attention and maybe that is why they call it "Helios" - like the sun-god. Suncollector units on the top of houses form the roofs of all 11 buildings to one unit. And with a shading calculation of 38 degrees, the optimal shape was found for them. Below the 982 m² roof area, a system of tubes meanders through the ground. The tubes contain a heat carrier medium transported under glass and warmed up by the sun. In order to balance seasonal fluctuations of the solar radiation, the housing area has an ingenious system of heat retention. It consists of a special heat storing unit and a subterranean storage, which are built up outside. In addition, this system has a natural groundwater conductor. With the use of solar energy it becomes possible to cover more than 60% of the whole annual need of heat. The rest will be covered by a conventional heating system with an ultra-modern heat-rating technique.

This principle leads also to reduced emission and less environmental pollution. The project was supported by the German Federal Ministry of Research and Mecklenburg-Vor Pommern. The construction costs per m² of living area were about 869 EUR and for the solar system of 138 EUR per m².

by Ms Renate Bremer