Influence of Wind Speed on Volcano Ash Removal From Self-Cleaning Cover Films Dedicated for Photovoltaics

Abstract

Soiling can significantly reduce the performance of photovoltaic (PV) modules. One source of soiling is volcano eruptions that eject dust contaminants, which can detrimentally affect PV systems. A microtextured fluoropolymer cover film for a PV module was evaluated as a passive antisoiling solution. In this case, the wind was investigated as a natural force to determine whether it can realize the desired self-cleaning functionality instead of the more commonly employed water droplets. Removal of dust particles of different size categories was investigated inside a wind tunnel. The results demonstrate dust removal of up to ∼90% from wind speeds of 8 m/s. Removal of small dust particles requires higher wind speeds compared with larger dust particles. Smaller dust particles were observed to be trapped within the microtexture cavities. Based on a multicrystalline PV minimodule, a performance recovery between 9.7%–24.0% in terms of short-circuit current density ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ), relative to the soiled device, was projected. Utilization of wind for dust removal shows potential but would require further optimization of the microtexture design to enhance the self-cleaning function.