Design and Implementation of an Open-Loop Solar Tracking System

Abstract

Solar tracker, by directing a collector face towards the sun, can maximize energy extraction from solar system. There are different ways of solar tracking. In this thesis work we aim towards developing an open loop solar tracker that tracks the sun about single tilted axis with an optimum tracker rotation. From time, date and location inputs taken into our device, we have calculated solar position using PSA (Platforma Solar de Almería) algorithm. From the calculated data we have optimized the single axis tracker rotation for maximum received solar radiation. We have implemented the optimum tracker rotation with a DC motor mechanically coupled with a linear multi turn wire-wound potentiometer. The potentiometer which is calibrated with respect to rotation angle sends a position feedback to the control unit. Depending on the given position feedback the control unit terminates the rotation at the required position (representing the respective optimum rotation angle) and goes through a definite interval. Thus the sun is tracked at certain intervals. In the design the robustness and reliability of the system has been emphasized. Finally we have experimentally analyzed the accuracy of tracking rotation and improved energy harvesting by tracking. The errors in angle range within ±5°. On a 30% overcast day, we have obtained 21% more energy by the designed tracking panel system with respect to a fixed panel system.