Performance Investigation and Analysis of Anti-Soiling Coatings in Hot Desert Climate

In this paper, the performance of hydrophobic coating on glass coupons and photocatalytic hydrophilic coating on solar modules installed in hot desert climate is analyzed using different test methods. Results reveal that after one month of outdoor exposure, and before cleaning the samples, the transmittance of uncleaned coated coupons reduced by 12.5% in comparison to 17.6% for the uncoated coupon. This result confirms the anti-soiling effect of the coating. After cleaning, the transmittance of the coated glass coupons under light exposure was slightly higher than coated coupons placed under shade, as well as higher in comparison to the uncoated coupons. This phenomenon could be caused by the degradation of the coating layer by light and high temperature. It is also observed that the wetting angle reduces with light exposure. In addition, the external quantum efficiency peak of the uncoated solar module was found to be higher than the coated module by approximately 1%. The I-V curves show higher power losses over the exposure time for coated module due to light soaking. These results provide an insight into the actual performance of different commercial anti-soiling coatings under hot desert conditions.