Analyzing wind cleaning process on the accumulated dust on solar photovoltaic (PV) modules on flat surfaces

In this study, the particle resuspension theory was used to estimate the wind cleaning process of the dust particles deposited on flat solar photovoltaic (PV) module surfaces. The model includes the effects of adhesion force, as well as, the hydrodynamic force and torque for rolling detachment model in the analysis. The required shear velocity and actual wind velocity for resuspension of particles with diameter ranging from 0.1 to 100 mu m were evaluated, varied from 0.23 to 57.56 m/s and 0.82 to 2219.8 m/s, respectively. The effect of particle size and composition on the required removal velocity was also analyzed. Verified with the experimental deposited dust size distribution, large particles with diameter larger than 1 mu m were effectively removed by wind. However, wind cleaning process for small particles was found not to be effective due to the large required shear velocity for detachment. In addition to particle sizes, the influence of compositions on the wind cleaning process can be negligible.