On the evaluation of wind loads on solar panels: The scale issue

Solar power can improve the quality of life and reduce dependency on traditional energies that are a significant source of pollution and global warming. Solar panels are common devices used for collecting solar energy. To balance between sustainability and resilience, it is essential to provide an accurate estimate of the design wind loads for the solar panels. Traditionally design wind loads for buildings and other structures are obtained using building codes and standards. The solar panels represent a relatively recent technology and indeed there is no complete guidance ready for codification of wind loads on these types of structures. Available wind tunnel data show discrepancies in wind loads on solar panels, owing to inconsistent model scales and test flows, among other factors. To eliminate such discrepancies in the test results and to allow for accurate wind load estimation, the current paper investigates the geometric scale and the inflow turbulence characteristics as potential causes of high uncertainties. Computational fluid dynamics (CFD) simulations are employed and results are compared with available wind tunnel data, as a complementary tool with a potential to simulate wind loads at full-scale. The results show that the geometric scale is a primary reason for the discrepancies in peak wind loads, which can be avoided by adapting the inflow turbulence and using a proper testing protocol. The results show an evidence of the correctness of a hypothesis that the lack of large-scale turbulence can dramatically affect peak wind loads on test objects. Consequently, recommendations are articulated regarding the best usage of the available wind load estimation tools. This is expected to lead to consistent and accurate results from wind tunnel testing and CFD simulations, a crucial step toward codification of wind loads on solar panels.