Sandstorm erosion testing of anti-reflective glass coatings for solar energy applications

Components for concentrating solar power applications can suffer from optical performance loss due to their permanent exposure to the environment. There is still lack of experience regarding the destructive effects of sand- and duststorms on glass envelope materials for receiver tubes of parabolic-trough collectors for iconcentrating solar power (CSP) plants. So far no accelerated aging guideline is formulated yet to account for the performance loss of optical components due to particle erosion to a realistic extent. Within this study 4 different anti-reflective (AR) coatings deposited on borosilicate glass are subjected to an artificial sandstorm test and their resistance towards erosion is evaluated. An uncoated borosilicate glass is also tested as reference. Noticeable differences were obtained depending on the type of coating. Microscope analysis and light transmission measurements in the spectrophotometer were undertaken and it could be concluded that the selection of an AR coating should not only be based on the initial optical performance but also in accordance with meteorological data, especially when erosive sandstorms are expected for the chosen site of the CSP plant.