Impact of dust deposition and brush-based dry cleaning on glass transmittance for PV modules applications

Here, we present research addressing one of the main challenges facing the efficient production of solar energy in arid regions where solar insolation is at its highest, but where the significant challenges of pervasive dust, sand storms and insufficient rain can dramatically alter the feasibility of harvesting solar energy. In this study, the impact of dust on the light transmittance through low iron glass was assessed for different periods of time. Additionally, different cleaning mechanisms were briefly reviewed including the promising technique of dry cleaning using robotic systems. This paper explores the effect of dry cleaning for the removal of dust particles settled down on glass and the impact of brushing on the transmission of the glass. It was demonstrated that dry cleaning using Nylon brushes does not have a significant, permanent effect on the optical characteristics of the glass surface, even when the brush is used to clean a dusty surface. Significantly, the process of brushing dusty samples does improve transmittance over the un-brushed state. However, the cleaning efficiency of the nylon brushes is not as high as cleaning using water and delicate wipers. The glass samples showed some changes in the surface of the glass after brushing, however, this was shown not to have a permanent effect on the optical characteristics of the glass after the simulated equivalent of 20 years of cleaning. Therefore, the data presented in this paper demonstrates the need for careful testing in the development and assessment of dry cleaning dust mitigation solutions. It also offers an indication of the technology's positive potential and elucidates some of the most important obstacles that need to be overcome. (C) 2016 Elsevier Ltd. All rights reserved.