The integration of transparent electro-dynamic screen (EDS) on the front surface of solar mirrors and glass cover plates of photovoltaic panels has a strong potential to significantly reduce the frequency of water-based cleaning needed to mitigate losses from dust depositions present in arid regions. The objective of our research was to develop and evaluate prototype transparent EDS-integrated mirrors and solar panels for their self-cleaning functions, with an aim to keep the collectors clean at a low cost without water or manual labor. This paper focuses on the design, fabrication, and laboratory evaluation of a prototype EDS integrated second surface mirrors and solar panels. The EDS consists of a set of parallel transparent electrodes screen-printed on the optical surface and embedded in a thin transparent dielectric film. By applying three-phase, low current, low frequency high voltage-pulses to the electrodes, electro-dynamic repulsion forces and a traveling wave are created for removing dust particles from the surface of the collectors. Design and construction of an environmental test chamber to simulate different atmospheric conditions of semi-arid and arid areas with respect to temperature, RH, and dust deposition conditions are briefly described. A non-contact specular reflectometer was designed, constructed and calibrated for measuring specular reflection efficiency of the mirrors. Laboratory evaluation of the performance of the EDS-integrated collectors was completed using humidity controlled environment test chamber where the prototype mirrors and panels were examined for their self-cleaning action. In each experiment, the solar collectors were loaded with dust until the specular reflectance of the test mirror or the short circuit current of the panel showed a significant decrease. The EDS was then operated for one minute and the relative output was recorded. The results show that the specular reflectivity of EDS mirrors and the short circuit current of the EDS panels can be restored by more than 90% of the values measured under the clean conditions.
Brush-painted superhydrophobic silica coating layers for self-cleaning solar panels
