Mechanism of photovoltaic module soiling in the presence of dew

Although condensation plays an important role in photovoltaic (PV) soiling, the mechanism of interaction among the condensate, dust particle, and PV surface has not been effectively elucidated. In this work, the dynamic behavior of dust/condensate during condensation and evaporation is investigated. Further, quantitative measurements are performed after drying. In addition, the effects of surface wettability and dust types on soiling are studied. A surface with a hydrophobic coating is found to have enhanced dust rearrangement/agglomeration by reducing surface coverage and particle adhesion . However, the hydrophobicity of particles is unfavorable because of the weak water-solid force. Based on these results, an explanative mechanism for the morphology and spatial distribution of dust mass after drying according to the force analysis is proposed. Two mechanisms account for surface soiling in the presence of dew: contact status between condensate and particles and condensation mode on the surface. This finding may guide the development of suitable strategies to prevent or mitigate soiling.