Wind loading and its effects on photovoltaic modules: An experimental–Computational study to assess the stress on structures

Photovoltaic modules are one of the intensively used technologies that provide a renewable energy alternative to electricity generation. Consequently, these devices have been studied using different approaches in order to determine their aerodynamic characteristics. Nevertheless, there is still a lack of guidelines from the codes of practice that could enable users and manufacturers to chose/recommend different types of photovoltaic modules according to siting and operation conditions. In order to provide more data about the influence of the photovoltaic module aerodynamics on its constitutive structural elements, an interdisciplinary approach is advisable. In this study the subject is addressed through experimental measurements and numerical assessment of a standard photovoltaic module under different conditions. Boundary layer wind tunnel tests were performed to determine wind loads over ground mounted photovoltaic modules, considering two situations: stand-alone and forming an array of panels. Several wind directions and inclinations of the photovoltaic modules were taken into account in order to detect possible wind load combinations that may lead to a condition not prescribed by the codes of practice. All tests were carried out using rigid models of the photovoltaic modules, that is, the experimental analysis is limited to static wind tunnel testing. A detailed numerical evaluation is performed using the finite element method (FEM) to identify critical structural sections. For the stand-alone case, the most influential wind flow directions correspond to oblique directions for local pressures and along wind direction for overall forces. For the case of the photovoltaic module array, it is observed that the wind loading over the leading panels is decisive for the design. According to the numerical results, the central support device is the most critical structural component.