Lifetime prediction model of reflector materials for concentrating solar thermal energies in corrosive environments

Abstract

Concentrated solar thermal technologies play an essential role in the energetic transition which is currently facing our society. The energy generation in this technology vastly depends on the optical behaviour of the reflector materials of the solar field. Corrosion of solar reflectors might be an issue in locations with high corrosive environments because an excessive corrosion of the solar mirror could be catastrophic for the profitability of the concentrated solar thermal plant. This research is focusing on modelling the durability of four different solar reflector materials exposed outdoors by accelerated aging tests. For this purpose, ten locations suitable for concentrating solar thermal applications were classified depending on their corrosive aggressiveness. Commercial, free-lead and low-cost reflectors samples were exposed in all the sites to determine the influence of the corrosion in its durability. Corrosion defects appeared in the solar reflectors during outdoor exposure were properly reproduced by CASS test. Novel lifetime prediction models were developed for all the solar reflectors depending on the corrosive aggressiveness of the place. Number and thickness of the paint coatings employed in the solar mirrors were identified as one of the most important parameters to improve the energy generation of a CSP plant in corrosive environments. A reduction of the capital invested in the solar mirror purchase is expected for sites with low corrosivity.