Solar Tracking Systems in Compound Parabolic Concentrators

The growing significance of solar energy as a sustainable replacement for fossil fuels is evident, prompting the adoption of solar concentrators like compound parabolic concentrators (CPCs) to tap into this resource. These concentrators, when paired with solar tracking systems, optimize energy yield by aligning with the sun's motion throughout the day and year. This article delves into solar tracking systems' role in CPCs, spotlighting their benefits, constraints, and ongoing enhancement endeavors. A solar water heating system employing a north-facing CPC design was devised for this study. The setup comprised a reflective aluminum foil concentrator enclosed in a commercial aluminum casing, insulated with polyurethane foam. A receiver, coated with matte black absorptive paint, housed a copper tube. A Programmable Logic Controller (PLC) managed the system, its performance superior and reliable. An algorithm was formulated to enable solar tracking using climatic data from a Davis weather station. The year-long meteorological data from the Polytechnic University of Puebla indicated effective solar radiation use, with temperatures surpassing 100 °C for 7–8 h when employing the solar tracking system. The control algorithm, programmed in MATLAB, utilized power, angular velocity, and torque equations to set control parameters. The study examined both PID and Fractional Order PID (FOPID) control methods. Integrating FOPID control into digital devices required Z-transform, with block programming through Simulink software. The FOPID control system's block diagram was outlined using Freescale technology. Validation via PLC-based FOPID control exhibited stable temperature responses with minimal variations due to thermal inertia. This project conducted at the Technological University of Puebla showcases the promise of solar energy, particularly with CPCs and solar tracking systems. The results contribute to environmental preservation and underscore the significance of sustainable energy sources.