Enhanced energy extraction in an open loop single-axis solar tracking PV system with optimized tracker rotation about tilted axis

Abstract

We compare the energy extracted from single-axis solar tracking systems employing optimized rotation about the tilted axis and the azimuth axis, respectively. It is shown that the optimized rotation about the tilted axis has the potential to extract significantly higher energy, particularly at lower latitudes. An open loop single-axis solar tracking system that tracks the sun through optimized rotation about the tilted axis is proposed and demonstrated. The system takes the location parameters, axis tilt, and the initial time and date as inputs and calculates the solar position at any given time. The solar position in turn decides the optimized rotation. In a prototype using a single potentiometer based angle determination method, the error between the computed and implemented rotation angles remains within ±3°. The tracking system with optimized rotation about the tilted axis extracted 20.01% more energy than a fixed panel system as opposed to 11.72% for that of the azimuth tracking system at the same tilt angle under identical conditions on a clear day at a latitude of 23.81°N. These percentage enhancements are in agreement with theoretical predictions. On a partially cloudy day, the advantages of the optimized rotational tracking about the tilted axis are diminished as the optimized rotational tracking system extracted 8.59% more energy than the fixed panel, whereas the azimuth tracking system extracted 7.86% more energy with respect to the fixed panel system at the same tilt angle at the same latitude.