Automated Sun-Tracking System as Part of the Photovoltaic Thermal Installation with Solar Radiation Concentration

Resumo

Automated Sun-tracking systems are important elements of solar power devices, which make it possible to increase the amount of solar energy converted to consumer formats during the daylight period, especially true for devices with solar energy concentration. In this study, we investigated the parameters of functioning of the Sun-tracking system built into the photovoltaic thermal installation with parabolic cylindrical concentrators of solar radiation, as well as the main characteristics of the complex as a whole. With attention to the installation structure and tracking system schematics, the studies were carried out on natural solar radiation, with simultaneous measurement of the photovoltaic characteristics and the solar radiation flux density using a pyranometer. The installation parameters were estimated in relation to the angular motion of the Sun across the celestial hemisphere. Due to numerous heterogeneous factors affecting the result, the experimental data were largely statistical in nature. For this reason, the parameters were evaluated using methods of regression analysis. In a number of experimental dependences, the correlation coefficient of the short-circuit current and the solar radiation flux density reached 98%. The studies allowed us to estimate the accuracy of Sun tracking at 1.5–2 angular degrees. In this case, the short-circuit current in the photovoltaic part of the installation varied by ±4% within an hour. In the course of field studies, the fraction of scattered solar radiation was estimated at ~20% of the total intensity. The concentration coefficient of 5.0–5.1 times was calculated from the dependence of the short-circuit current on the solar radiation intensity.