Artificial Soiling of Functional Coatings and Performance Testing
Christiane Siess, Thomas Kaltenbach, Markus Heck, Elisabeth Klimm
Fraunhofer ISE, Freiburg, Germany

The accumulation of dust can cause significant performance losses of solar energy systems, unfortunately especially on sites which are most attractive for the use of solar energy. In this paper, we share an evaluation of dirt repellent coatings as a way of mitigating those effects. For that purpose, a set of solar glass samples with different anti-soiling coatings has been analyzed and artificially soiled, before exposing it at an outdoor weathering test site in Freiburg for several weeks. It has been found that all of the samples could almost fully recover their initial transmittance after a moderate or strong rain event. Light rain and morning dew, however, seem to further enhance the problem.