A comparative analysis of opto-thermal figures of merit for high temperature solar thermal absorber coatings

Solar thermal absorber coatings play a key role in the efficiency of receivers for applications field Concentrated Power (CSP). The development stable spectral selective with high solar absorptance αsol and low emittance εth is often desired to reduce losses. However, quantitative indicators describing selectivity trade-off between seldom discussed literature. In this review, relevant opto-thermal figures merit are analyzed comparison reference coatings, including real ideal both black selective. made temperature ranging from 25 1000 °C concentration factor 20 1000, based on data measured at room 0.25 μm. New introduced, i.e. normalized ratio Si*, Ztrade-off, reflectance index SRI* peak Tpeak,opt. These metrics derived existing adapted CSP. set review offer complementary perspective detailed characterization any coating performance. For ηthermal Tpeak,opt respectively deemed more insightful than ηopt-th maximum steady-state TSST,max, when comparing relative performance two formulations.