Improvement in PV output using a simple single-axis tracker

Abstract

A major portion of the 10% energy yield targeted to be reached locally through renewable energy sources by 2020, can be met by installing PV panels. However, such a course of action will come across constraints that have to be dealt with to achieve that end. On the one hand, Malta’s geographical position gives it a great solar potential which should be fully exploited, yet on the other hand its limited surface area of 316km2 , together with its dense population, present a drawback that rules out sizeable inland solar farms. This work is an attempt to find an alternative to the current local situation regarding PV module installations. At present, the accepted policy followed is to install fixed PV arrays to maximise the energy yield which is in turn fed into the grid. The study looks into ways how the existing approach can be reviewed, revised and bettered if the stationary arrays found on domestic, public and industrial rooftops were replaced by tracking PV systems, and what the outcome would be. Detailed analyses, backed by concrete results, were taken up to find out whether opting for different yet simple single-axis solar trackers was more effective in the harvesting of solar energy. Besides, the trackers themselves were then compared to find which one gave the best yield. Moreover, the matter of lowering the reference tilt angle from 30° to 15° to shorten the shadow length, thus enhancing the roof area and whether this adversely affected the amount of energy produced was also explored. The device with a 15° inclination would be an ideal structure for sites of historical importance as it would minimise any unsightly visual impact in aesthetically sensitive areas. The preceding construction stage entailed designing and building four structures on which five identical panels were mounted. The east-to-west diurnal solar tracker had both the 15° and 30° tilt angles fixed to one and the same structure, while the variable tilt tracker was a separate set-up. So were the two stationary set-ups, one at a 15° inclination angle, the other being the reference at 30°. A data logger monitored and registered throughout all the power that was generated. The study also entailed investigating the capital cost and rate of return from the set-ups if each was to be installed as a distinct PV array.