Mitigation of Dust Impact on Solar Collectors by Water-Free Cleaning With Transparent Electrodynamic Films: Progress and Challenges

Energy-yield loss caused by soiling of photovoltaic modules and concentrated solar power (CSP) mirrors in utility-scale power plants installed in semiarid lands and deserts would result in unsustainable demands for fresh water needed for cleaning. This paper reviews the progress of the electrodynamic screen (EDS) film technology for frequent water-free cleaning with low-energy requirements. Results presented here, based on laboratory-scale EDS-film-laminated solar panel cleaning, show that the output power can be restored higher than 95% of the initial power under clean conditions. For solar mirrors, the specular reflection efficiency can be maintained over 90% ensuring high efficiency of the CSP plants. Operation of the EDS film for maintaining high optical efficiency of solar collectors requires less than 0.2 Wh/m(2)/cleaning cycle. Principles, optical modeling, construction, lamination of the EDS films on modules and mirrors, and experimental data showing optical efficiency restoration without water consumption are presented. Current challenges in developing electrodes that would meet optical and conduction properties, low-cost production, and meeting long-term outdoor durability of the EDS films are discussed. Index Terms-Cleaning,