Accelerated ageing tests for durability study of solar absorber coatings on metallic substrate for solar thermal energy (STE) application

摘要

The Concentrated Solar Thermal Energy (STE) system requires components with a lifetime of more than 25 years to be profitable. Optical materials performances, such as mirrors and absorber coatings, are essential to the efficiency of the system. Any degradation of their optical properties leads to a reduced efficiency. In the frame of STAGE-STE project we are studying the durability of solar absorber coatings on metallic substrate for non-vacuum applications (in air). The definition of the test conditions was based on a critical review of the stress factors affecting the material such as temperature, humidity and saline atmosphere. The optical performances were measured over time for each sample to follow the variation of solar absorbance and emittance. For each test, a comparison of the performance criterion (PC=Δα-0.5ε < 0.05) variation gives a relative resistance of each absorber to the corresponding stress factor. In this paper we will present the results of the accelerated tests campaign on the three solar absorbers samples. Materials characterization was used to analyse the degradation process occurring on each sample. A lifetime prediction based on the calculation of the activation energy has been presented for the thermal test. Finally, the relevance of each test has been discussed.