a low-cost dynamic shadow detection system for site evaluation

Abstract

Partial shadowing caused by moving clouds results in spatially and timely alternating supply of direct irradiation to large solar collector fields with extensions of 1 km² and more. Fluctuating inhomogeneous irradiation may lead to harmful dynamic changes of load and temperature in various components of CSP plants. In order to avoid harmful wear and stress the power stations have to be shut down under these weather conditions and production capacity is lost. On the other hand, operation and control strategies for continuous plant operation can be developed with dynamic simulation when appropriate data is available. The paper gives an overview on existing cloud and shadow detection methods and presents a new system for dynamic cloud detection based on autonomous miniature light sensors. Performance analysis by simulation and laboratory experiment was done and showed the feasibility of the system. The cost of the system is estimated as about 10 k€, independent from the field size. The system is especially applicable for site evaluation as it is completely independent from other installations