Performance evaluation of sun tracking photovoltaic systems: A case study

This paper presents a case study to investigate the performance of Photovoltaic (PV) systems with optimally selected sun tracking for Indian climate. In order to achieve this, the performance of single axis and two axis sun tracking is compared. The single axis tracking further includes horizontal east-west, horizontal north-south, fixed slope rotated about vertical axis and north-south parallel to earth´s axis tracking. The mathematical model to find solar radiation, different tracking angles and output electrical power from a PV module is also presented. In addition to this, the paper also presents the effect of varying the tilt angle on collected monthly solar radiation. The performance analysis is done for the climate condition in Roorkee, India. All the models are simulated using the script file in Matlab for daily, monthly, seasonally and annual periods. On the basis of annual and daily analyses, maximum solar radiation is collected using two axis tracking compared to the single axis tracking and fixed horizontal surfaces. In case of Roorkee, the yearly radiation gain by two axis tracker is 3.7% and 47.3% with respect to single axis tracking and fixed horizontal surfaces, respectively. The result from seasonal analyses shows that two axis tracking surfaces provide better performance as compared to single axis tracking for the autumn and winter season and both gives the same performance in spring and summer seasons. The result indicates that two axis tracking is optimal system for Roorkee climate if it rotates about horizontal north-south single axis for spring and summer. In this way initial cost, complexity and extra input solar energy can be reduced. If the tilt is set to be approximately equal to latitude, the average optimal energy can be collected. The PV module using two axis tracking annually gives 11.12 kW maximum electrical power output, which is approximately twice the annual power generated by the fixed horizontal surfaces.