Performance of Photovoltaic Modules with Self-Cleaning Coating Surface After Two Years of Outdoor Exposure in South Spain

Abstract

The deposition of a film with self-cleaning and anti-reflective properties on the surface of the modules reduces the soiling losses and facilitates cleaning when it rains. In this paper we present a comparative study of the performance of photovoltaic modules with and without coating in order to determine the soiling losses as well as the influence of tilt angle on these losses. Two different procedures for quantifying soiling losses have been used: The first one measuring transmittance losses of the module and the second one analyzing the values of the daily performance ratio. Measurements were carried out for two periods: the photovoltaic modules were placed with a south orientation and 21° (first period of measurements) and 40 ° (second period of measurements) tilt angles. The obtained results show that coated modules exhibit lower soiling losses that those without coating and therefore better values of daily yield. Then, soiling losses depend on the module tilt angle and are lower when module inclination is higher.