Droplet dominated dust removal and power recovery under varying surface wettability and panel inclination

Surface soiling on photovoltaic modules weakens incident irradiance and can markedly impair electrical output. In this work, droplet-assisted cleaning is investigated as a route for recovering PV performance. Droplet dynamics are resolved with a multiphase VOF formulation, and droplet-particle adhesion and transport are described through an API-based liquid-bridge force model. Particle settling on PV panels with different inclination angles is first quantified, and the resulting influence on electrical performance is then evaluated. The removal behavior of droplets over surfaces with different contact angles is further analyzed, together with the corresponding recovery of PV output. The modeling framework is verified by comparison with theoretical predictions and experimental observations. The results indicate that increasing the panel tilt from 20° to 40° reduces the deposited dust density from 4.79 g/m 2 to 4.19 g/m 2 , while the generated power increases from 3.99 W to 4.10 W. A lower surface contact angle generally improves droplet-based cleaning. In this research, the maximum removal ratio reaches 25.9% at a 90° contact angle and a 30° panel tilt, where the PV output increases by 5.2%; by contrast, a 170° contact angle gives the lowest removal ratio of 11.8% and a power gain of only 2.4%. Furthermore, the droplet cleaning efficiency decreases with particle density but increases with droplet diameter. These findings offer guidance for optimizing wettability and inclination in self-cleaning PV module design.