Design and Characterization of a single-axis solar tracker system for Small Scale Parabolic trough collectors

Abstract

ABSTRACT This paper introduces a detailed design and development of a solar tracker (ST) prototype for small-sized parabolic trough collectors (PTCs) with one degree of freedom. The PTCs are intended to produce industrial heat at a moderate temperature. The contribution of this work lies in its introduction of a new and optimized solar tracker, which prioritizes both accuracy and cost-efficiency in its design. This aspect was emphasized throughout the experimental investigation, along with a comparison of findings from existing literature. Therefore, the open-loop strategy based on the solar position algorithm (SPA) is adopted here to determine the tracking-elevation angle. A software algorithm is proposed and implemented in a control unit managed by low-cost board. Then, the tracking angle is updated by controlling the electro-mechanical system using an on-off hysteresis approach. An experimental characterization of the tracker is carried out regarding the tracking precision by directly measuring the errors in positioning angle and their impact on the optical losses. The obtained results show good performance of the tracker with a standard deviation of tracking errors of 0.55°, which is adequate for such collectors with tolerance angles of more than 2°. This makes the 96th percentile of the optical loss efficiency almost zero for our PTC.