Effects of particle sizes and tilt angles on dust deposition characteristics of a ground-mounted solar photovoltaic system

The dust deposition behaviours of ground-mounted solar photovoltaic (PV) panels and their effects on the PV efficiency were numerically investigated. The shear stress transport k-ω turbulence model with the inlet user-defined function profiles and the discrete particle model were used to predict the wind flow fields and the dust deposition rates of a PV panel. A grid independence study was conducted, and the mean pressure coefficient was validated with the related experimental data. The effects of the different dust particle diameters and the different tilt angles of the PV panels on the dust deposition characteristics were investigated carefully. The results showed the dust deposition rates of a PV panel were considerably affected by the different tilt angles. The dust deposition rates were considerably higher for the upward PV installations than for the downward ones. Moreover, the dust deposition rates were greater when the solar PV panel was more horizontal with the ground. The peak deposition rates were observed for the 150-μm dust particles for all of the tilted PV panel angles. The maximum deposition rates were 14.28%, 13.53%, 6.79% and 9.78% for the tilted PV panel angles of 25°, 40°, 140° and 155°, respectively. Moreover, the main deposition mechanisms of the solar PV panel were analysed and discussed for the different dust particle sizes and PV panel installation angles. Finally, an empirical model was developed for estimating the PV output reductions caused by the dust deposition for different tilt angles, which could be applied in practical engineering applications.