Hybrid Strategy for Bi-Axial Solar Tracking System

The technical efficacy and economic sustainability of modern solar conversion systems are strongly related to the level of irradiance incident to the solar collector and, then, converted to heat and/or electrical power. A sun tracking system represents an effective solution to achieve the purpose of obtaining a significant increase of the performances of solar energy systems. Aim of this paper is to present a hybrid strategy for altitude-azimuth sun tracking system applied to solar energy conversion plants. The proposed approach allows to follow the Sun apparent motion, from sunrise to sunset, thanks to a proper combination of both a forward and a feedback control loop. A completely automatic real-time monitoring platform, developed with LabViewTM programming language, implements the proposed control strategy so that the sun collimation is guaranteed on both axes of motion. Preliminary positioning before sunrise and system switch off at sunset or due to the occurrence of danger conditions are, also, properly considered. Details about these logics of control and the required device to implement them are widely discussed in this paper. The developed strategy and device are applied to a solar concentrator system to test accuracy in sun collimation. A trial campaign is conducted considering different setting conditions. Obtained results are presented and properly commented.