Design of a dual axis solar tracker concept for photovoltaic applications

Solar energy is an abundant and clean resource. However, solar energy applications face challenges of low efficiency and high capital investments. To mitigate low efficiencies, electro-mechanical trackers that follow the sun path to enhance reception of solar energy are used. Usually these devices are complex in design. In this study, a simpler and less energy consuming dual axis solar tracker concept is designed and evaluated. A design process model consisting of the three main phases; planning, functional analysis, and design evaluation, was used. The planning phase involved the generation of design requirements and constraints. During this phase, existing dual axis solar trackers were reviewed, an energy output efficiency map was generated, and the fundamental functional objectives embodied in the most efficient ones were collated. In addition, design requirements of an existing 1.3 MW photovoltaic solar power plant at Phakalane (Botswana) were established using a questionnaire and interview approach by the author.

From the collated functional objectives and the generated requirements from the Phakalane solar plant, key requirements and constraints were identified which were then used to generate design alternatives of a less energy consuming and a simpler dual axis solar tracking system, using a functional analysis technique. From the design alternatives, the best concept was selected using a weighted evaluation matrix based on a five point Likert scale. A three dimensional solid model of the selected concept was developed using a SolidWorks® platform. The concept was then, compared to existing dual axis trackers, on the basis of design complexity and energy consumption of the position mechanisms using Keating (2000) design complexity metric and a What-If analysis, respectively. The designed dual axis solar tracker concept was found to be ten per cent (10%) less complex when compared with existing trackers. Therefore, this study realised a simpler and less energy consuming dual axis solar tracking concept for implementation.