By Klaus Hennecke, DLR, Germany
4. Design, materials and requirements to operate parabolic trough systems with new Silicon Oil as new HTF
State of the art parabolic trough power plants utilize a eutectic mixture of diphenyl oxide and biphenyl as the heat transfer fluid, which limits the maximum operating temperature of the solar field to about 400°C. Recent developments of silicon oil promise increased thermal stability, enabling improved performance of the power cycle due to increased operating temperatures. Furthermore, freeze protection equipment and operation will be greatly reduced due to the low freezing point. To fully reap the benefits of the new fluid, the design of turbine cycle, solarfield, field piping and storage system should be adapted to the advanced properties.
5. Potential use of solar thermal energy in industrial processes
With an annual demand of approximately 300 TWh in the mediterranean countries alone, industrial process heat at temperatures up to 250°C is a significant potential market for solar thermal technologies. A major barrier for their wide spread application is the need for individually engineered solutions for each application, taking into consideration the relevant process parameters and site specific conditions. Design guidelines for the appropriate integration of solar heat into industrial processes developed within a joint task of IEA Solar Heating and Cooling and SolarPACES will be presented together with examples of realized pilot systems.
Klaus Hennecke is the Head of Department of Line Focus Systems at the DLR Institute of Solar Research. In the current work of his department emphasis is on co-operation with industry to support the development and market entry of the next generation of parabolic trough and linear Fresnel technologies.
Qualified as Aerospace Engineer in 1978 at the Federal German Forces University in Munich, Klaus Hennecke started his career as air engineering officer in the Federal German Navy. Since joining DLR’s Energy Technology Division in 1989, his work has mainly been related to parabolic trough technology with a special focus on processes and system integration for alternative heat transfer fluids to achieve cost reductions and increased system performance. Within the IEA SolarPACES cooperation, he is the Operating Agent for Task IV: Solar Heat for Industrial Processes.