Pinhole Camera Sun Finders: On Field Characterization

The use of sun finders is essential to optimize the performance of solar concentration systems. A sun finder based on the pin-hole camera principle has been developed for Concentrating Photo Voltaic systems, which require pointing precision of the order of 0.01 angular degrees. Several configurations of this device were implemented and they were tested in laboratory and outdoor. This paper discusses the outdoor characterization of a set of sun finders, analyzing the results. Features and performances measured in real conditions are in good agreement with the data obtained in the laboratory, under controlled and reproducible conditions. The field of view of the sun finder can be customized by varying the pinhole-detector distance allowing to use it in many applications. Even if the results show that the pointing precision exceeds 0.01 degrees, the sun finder is simple, useful, adjustable and economic.