Review of the spectrally selective (CSP) absorber coatings, suitable for use in SHIP

Abstract

A key component in the conversion process of concentrated solar power (CSP) into thermal energy is a solar absorber coating. Many experimental and simulated coatings for various substrates for CSP water/steam or molten salt absorbers have been developed. The main challenges today remain in the selection of a low-cost and effective fabrication method, appropriate for industrial production, and assessment of the degradation rate and service life of these coatings, which affect the efficiency of the plant and the LCOE. In this article, we review different types of mid- (100 < T < 400 °C) and high-temperature (>400 °C) absorber coatings and their fabrication methods. The emphasis is on the solar absorptance, thermal emittance and the long-term (>10 years) thermal stability of the coatings. Spectral selectivity of the coatings, which is more difficult and expensive than other means, was proven to be essential for a low-to-mid temperature range and low concentration ratios, yet for high temperatures and high concentration ratios, high solar absorptive coatings can achieve the same or even better performance than spectral selective ones. Important factors for an efficient CSP absorber are compatibility of the coating and substrate under cyclic temperature conditions and high heat transfer rate to a heat transfer medium.