Combined Soiling and Abrasion Testing of Antisoiling Coatings

Soiling of photovoltaic (PV) modules reduces the energy yield and can lead to extremely high losses, especially in desert environments. Therefore, Antisoiling coatings (ASC) are developed to reduce the dust accumulation, but, even if the coating can reduce natural soiling rates, frequent cleaning is still necessary. However, regular cleaning of PV modules by using dry brushes or other technologies can damage the coated glass surfaces. In this article, the damage and abrasion potential of harsh dry brush cleaning is examined for three different ASC, which also possess antireflective (AR) properties. Both changes of antisoiling functionality and antireflective properties are investigated in detail by spectroscopic sample characterization and advanced laboratory soiling tests in a dust chamber. The results indicate significant degradation of the optical and antisoiling properties of the coatings depending on the number of brush cycles used. However, the results suggest that by using more gentle cleaning technologies, the coating functionality could be maintained throughout typical lifetimes of PV modules.