Optical sensors for solar pointing

A simple, efficient and low-cost sun tracking method is presented: it is based on optical pointers used as "sun finders" and on a double guiding system. A passive tracker provides the preliminary orientation, then an active system with the sun finder realizes fine positioning and adjustments. Two optical sensors for solar pointing are proposed discussing working principle and applications. The two-axis pointer is appropriate for solar concentrators coupled to optical fibers or tiny photovoltaic cells; while the one-axis sensor is suitable for linear tracking collectors. They can be adapted to every specific application and to every solar collection device. The sensors were optically characterized indoor, under controlled and reproducible conditions, and outdoor in real working situations.