J. NuBbicker, Institute for Thermodynamics and Thermal Engineering (ITW), University of Stuttgart

D. Mangold, Solar — und Warmetechnik Stuttgart (SWT, ein Forschungsinstitut der Steinbeis-Stiftung)

W. Heidemann, Institute for Thermodynamics and Thermal Engineering (ITW), University of Stuttgart

H. Mtiller-Steinhagen, Institute for Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Solar — und Warmetechnik Stuttgart, DLR Stuttgart Institute for Technical Thermodynamics

The solar assisted district heating system with seasonal duct heat store in Neckar­sulm-Amorbach is being realised since 1997. In 2003 about 200 accommodation units, a school with gymnasium and a shopping centre were supplied with heat by the district heating system. So far 5,263 m2 of solar thermal collectors are installed; the volume of the duct heat store is presently 63,360 m3. In the duct heat store heat delivered from solar collectors is stored from summer to winter. The duct heat store was extended twice; the operation of the first and second extension started in 1999 respectively in 2002. The maximum temperature in the duct heat store is expected to be about 85 °C. In 2002 and 2003 a solar fraction based on the total heat demand (space heating and domestic hot water) of 39 % was reached. The planned solar fraction of 50 % is expected to be reached within the next years. This paper presents an overview about the present status of the system as well as operational experiences and characteristic data for the system.