The assessment of reflector material durability for concentrated solar power based on environment exposure and accelerated aging test

Abstract

The reflector durability is essential to maintain suitable photo-to-thermal conversion in concentrated solar power plants. The present study evaluates the impact of environmental exposure and accelerated aging of the reflector material. The study is conducted to assess the reflector material's durability to withstand environmental exposure and accelerated aging test. The evaluation is conducted using four different reflector materials commonly used in concentrated solar power: stainless steel and silvered-glass mirror (solid-state reflector), aluminum and silvered-polymer film (sheet-based reflector). The environmental exposure and accelerated aging test are conducted for 1,080 hours according to the standard reference of ISO 8565:2011 and ASTM B117–11. The mass loss after exposure is used as a reference to determine the corrosion rate for each reflector. Further observation is conducted by using microscope light to observe the effect of exposure on the surface of the reflector. Each reflector indicates a different corrosion rate which implies different weather resistance for each reflector type. The highest corrosion rate is found on aluminum film, with a value of 295.8 g/m2.year. The accelerated aging test through neutral salt spray demonstrates that a metallic reflector has a higher corrosion rate compared to a silvered-glass mirror which uses silicon dioxide as the top coating. Microscope observation demonstrates that suitable protection from soiling elements for the silvered-glass mirror is mainly caused by the presence of silicon dioxide on the top surface of this reflector. The assessment suggests that a suitable coating can be developed to be used for reflector protection. Furthermore, the corrosion mechanism is observed clearly, which can be referred to the synthesis of new reflective material that withstands environment and salt exposure.