Solar mirrors coatings contribution under arid climate and different exposure conditions.

Solar mirrors are usually implemented on desert sites despite the arid meteorological conditions to take advantage of the high irradiation rate. These sites are characterized by high wind speeds which transport sand, dust and fine particles from the ground to the reflectors surface causing significant mechanical damage. Two major performances degradation could be observed in this type of environment: erosion and soiling. These two phenomena are impacted by several parameters including the nature of the mirror surface (coated, uncoated...), the weather conditions of the site (wind, humidity, rain...) and the mirrors configuration (inclination and orientation). In order to assess the impact of solar mirrors configuration, a study was carried out by exposing several types of solar mirrors in a desertic site on a special rack with varying inclination angles (0°, 45°, 90° and 135°) and facing two different directions (North and South). The weather data analysis showed that the dominant wind speeds come from the north direction, so the samples oriented in this direction undergo more degradation and the 90° inclination reach the greatest reflectance loss values. After 12 months of exposure, unexpectedly, the hard-coated samples show significant loss values compared to uncoated and antisoiling samples. [ABSTRACT FROM AUTHOR]