Solar Reflector Materials Degradation Due to the Sand Deposited on the Backside Protective Paints

Concentrating solar power (CSP) technologies are foreseen to be a crucial actor in the future renewable energy mix. Soil accumulation on the optical surfaces of CSP plants involves significant expenses of the operation and maintenance activities because a high cleanliness level is required to achieve proper plant revenues. Normally, only the front side of the solar reflectors is cleaned to reflect the maximum possible amount of direct solar radiation towards the receiver. However, soil deposited on the backside of the reflector could provoke degradation and might need to be considered in the cleaning strategy. As this possible degradation has never been studied, this work is dedicated to assess if the backside of reflectors should be regularly cleaned. The influence of the sand in the possible paint degradation depends on its chemical composition and the weather conditions. Therefore, several climatic conditions of artificially soiled reflector samples with different types of sand were simulated in accelerated aging tests. Concerning the results obtained, the ambient conditions simulated by the damp heat and thermal cycling tests were the only ones that produced a significant degradation of the backside paints. Also, the sand from Ouarzazate was responsible for higher deterioration.