Novel high precision low-cost dual axis sun tracker based on three light sensors

This study aims to test a new type of dual axes solar tracker based on just three Light Dependent Resistors (LDR) as optical sensors in order to achieve a high precision sun tracking that satisfies the requirements of solar concentration systems. This new system is integrated into a solar concentrator that uses a set of Fresnel mirrors and an evacuated tube collector as an absorber so that it can be used as a solar water heater. The 3D-printed support that holds LDRs have three compartments to maintain the three LDRs firmly in their place. One is placed on the left and the other on the right side of the support. These two LDRs are responsible for the azimuthal tracking while the third LDR is placed in the center and its responsibility is elevation tracking. This central LDR is covered under an alveolus hollow tube with a length of 45mm crossed all along its center with a 0.4mm slot that lets sun rays reach the central LDR at the bottom of the alveolus hollow tube. A setup was made to collect data based on a pyranometer and three thermocouples positioned at specific points on the evacuated tube collector to record the temperature variation.