Performance assessment of the anti-soiling coating on solar mirrors soiling in the arid climate of Ouarzazate-Morocco

Abstract

Soiling of solar reflectors is a great challenge in regions with high aerosol concentrations and little rain such as arid and semi-arid climates. Actually, cleaning operations of the solar field in the CSP plants take a crucial part in the O&M costs. Coating is among the preventive mitigation methods, aiming to repel the dust from the solar collector’s surface. This approach based on the treatment of surface properties, has seen a great technological development in the last few years. In this paper, the performance of an anti-soiling coating applied on several sets of mirror samples has been evaluated in real outdoor conditions on different heights at the arid site in Ouarzazate. Systematic measurements of the cleanliness factor during a year of exposure have been analyzed, taking into account the nature of the surrounding environment. Through this work, many findings have been obtained, which are considered very promising for the studied anti-soiling coating. The coated mirrors have shown a positive performance during the whole period of exposure, where the maximum cleanliness gain has achieved 7 pp. It was found that a maximum soiling rate of 2.54 pp/day was attributed to uncoated samples. This coating has significantly reduced the number of soiling particles deposited on the mirrors surface by 75.5%. This result is considered very valuable for the anti-soiling coating, enhancing its application in sites characterized by high levels of soiling.