TiO2-based nanocoating with self-cleaning and anti-reflective properties: effects on PV performance

Photovoltaic modules operating in field conditions exhibit a significant reduction in their power output due to dust accumulated on their surface. Depending on the amount of dust accumulated the reduction in peak power has been reported in the range of 5-15%. The accumulated dust is linked to meteorological and environmental parameters such as humidity, precipitation, solar radiation, ambient temperature, dusty winds, air pollution, etc., but also to the location and surroundings of the installation and the period for which the PV modules have been left without cleaning. To reduce the effect of dust, research has been recently focused on coatings with self-cleaning properties that may be applied on PV glass surface. Also, coatings with spectral selective properties have been investigated to enhance PV performance. The purpose of this study is to examine the effect of a nanocoating with self-cleaning and anti-reflective properties on the performance of a PV module when applied on its glass surface. Particular interest is given to its anti-reflective properties which are assessed for angles-of-incidence of solar radiation greater than 40o, where reflectance is generally higher. The performance of two same PV modules one with and one without the coating is compared.