The new hydro-mechanical solar tracker: Performance testing with a PV panel

Abstract

This paper describes work carried out to test the performance of a newly invented solar tracker. It is a gravity driven, bladder-flow controlled, Hooke coupled inclined non polar axis solar tracker. The performance of the tracker when coupled with a PV panel was first modelled in MATLAB® using the Perez anisotropic diffuse radiation and the King cell temperature models. Experiments with two identical 90 Wp panels were done over a 40 day period in outdoor conditions. One PV panel was fixed on optimised slope, the other, was driven by the tracker about a similarly sloped axis. Weather data consisting of total and diffuse radiation, ambient temperature and wind speed was also collected using a Campbell Scientific weather station adjacent the panels. This data was used to simulate performances of the panels in the MATLAB® model. TRNSYS simulations were also done for the two panels. The three sets of results were compared. It was found that the tracked panel yielded 34% more energy than the fixed one and that the experimental results correlated more closely with the MATLAB® models than with TRNSYS ones. Results also indicated that the efficacy of the tracking device could be influenced by the timing of cloudiness during the day and by wind speed.