Design Review of German Central Solar Heating Plants

Members of the Working Group on Central Solar Heating Plants with Seasonal Storage (CSHPSS) gathered in Stuttgart, Germany in March 1995 to review the design of two German demonstration projects which are in the final design phase. The meeting was attended by 38 participants from seven countries.

The first project, located in Hamburg-Bramfeld, consists of several small blocks of 124 terraced houses. The estimate annual heat load is about 1,550 MWh. The solar heating plant, designed to cover 60% of the annual load for an average year, comprises 3000 m2 of roof-integrated collectors and 5000 m3 of water storage in a partially-buried concrete tank.

The building project in Friedrichshafen-Wiggenhausen/Sud consists of 570 apartments in eight multi-family blocks. The estimate annual heat load is about 4,100 MWh. The solar heating plant, designed to cover 47% of the annual load for an average year, comprises 5600 m2 of roof-integrated collectors and 12,000 m3 of water storage in a partially buried concrete tank. The building project will be constructed in two phases.

The first large solar heating plants were built in the late 1970's, with Sweden as the main pioneer. These plants were followed by several others in Denmark, the Netherlands, and Finland, as well as additional ones in Sweden. The present development scene is dominated by Germany where a number of small pilot plants have been built during the past three years and several large demonstration plants are planned.

Two major types of plants can be distinguished: district heating plants using ground-mounted collectors and group heating plants using roof-integrated collectors. Plants with ground-mounted collectors are found mainly in Sweden and Denmark while plants with roof-integrated collectors are found mainly in Sweden, Denmark, Germany and Austria. Systems with short-term storage are for the most part an established technology. The major challenge is to demonstrate more cost-effective seasonal storage applications in order to achieve high solar fractions (50 - 80%).

International cooperation on Central Solar Heating Plants with Seasonal Storage (CSHPSS) began in 1979 in the framework of Task 7 which lasted for 10 years. A working group was formed to continue exchange of information on this technology and to review the design of new plants.

The CSHPSS Working Group is currently led by Jan-Olof Dalenbäck, Chalmers University of Technology, Sweden. Fax: 46-31-772 1152