Concentrating Solar Collectors for Process Heat up To 250°C and Small-Scale CSP – Integrated Optical Design for Improved Performance
Abstract
Concentrating solar collectors like small Parabolic Troughs and Linear Fresnel Collectors are particularly well suited to generate process heat at temperatures between 120 °C and 250 °C in countries with a high potential of direct irradiation. Other applications are combined solar generation of solar heat, industrial cold and electricity, especially in regions with instable power supply and within island grids. The economic viability of such systems and applications has been shown in a study carried out by Fraunhofer ISE (MEDIFRES). With our integrated design approach we are supporting industrial partners in the development of small scale collectors by systematically investigating the effects of reflector material, geometrical configuration, manufacturing and site specific conditions. We characterize relevant components in the laboratory and use the detailed results in our design studies. Combination of sophisticated optical modeling via ray tracing, experimental testing and site conditions results in optimal matching of collector geometry and materials ass well as optimized performance and more precise yield calculations. The detailed optical modeling provides the basis for an overall cost-optimized collector design. Exemplary results of a design study for a small parabolic trough using aluminum reflectors are shown, focusing on the influence of optical errors and collector geometry on performance.