CFD simulation and validation of a self-cleaning solar panel surface with superhydrphilic coating

Solar panel conversion efficiency, typically in the 20 percent range, is reduced by dust, grime, pollen, and other particulates that accumulate on the solar panel. Cleaning dirty panels to maintain peak efficiency is especially hard to do for large solar-panel arrays. The purpose of this study is to develop a transparent, anti-soiling Nano-TiO2 coating to minimize the need for occasional cleaning. In our study, a 2-D rainwater runoff model of tilted solar panel surfaces based on the Nusselt solution was established to have a better understanding and to predict the behavior of runoff rain water, especially when in contact with solar-panel surfaces with Nano-TiO2 coating. Our simulation results demonstrate that solar-panel surfaces with Nano-TiO2 coating create a smooth glass surface which cannot hold water, showing features of more pronounced and increasing runoff water film thickness and velocity compared to the uncoated surfaces during a rain event resulting in a better self-cleaning effect. Validation of our model was performed on titled solar panels in real time outdoor exposure testing in Germany and Switzerland. It was found that dust particles do not readily adhere to the surfaces of the coated slides when compared to uncoated slide surfaces, thereby showing great potential for its use in harsh environmental conditions. This study suggests that application of the super-hydrophilic self-cleaning solar panel coating maximizes energy collection and increases the solar panel's energy efficiency.