Spectrally selective ultra-high temperature ceramic absorbers for high-temperature solar plants

Abstract

Ultra-high temperature ceramics are the ideal materials for extreme conditions owing to their very high melting points and good thermo-mechanical properties at high temperatures. For these reasons, they are widely known as materials for aerospace applications. This paper presents a comparative spectral characterization of zirconium, hafnium, and tantalum carbides ultra-high temperature ceramics for concentrating solar power applications. Room-temperature reflectance spectra have been measured from the ultraviolet wavelength region to the mid-infrared band. Using these spectral properties, the ceramics were evaluated as sunlight absorbers in receivers for high-temperature thermodynamic solar plants. V

Optical properties of black and white ZrO2 for solar receiver applications

“…Very recently, our group has studied several non-oxide materials belonging to the family of ultra-high temperature ceramics (UHTCs) [5][6][7][8][9][10], showing promising characteristics for solar absorber applications.…”

Control-Oriented Concentrated Solar Power Plant Model

“…These changes are at least 25-50 times that of any conventional power plant. The metal temperatures range from ambient to over 700°C on a daily basis during startups and shutdowns [9], and with transient clouds the solar irradiance can be reduced by 5% per second resulting in 600°C per minute change in metal temperature at high flux points on the receiver [10]. These conditions cause significant thermal stresses in materials which reduce the lifetime of the plant and increase maintenance costs.…”

The effect of increasing Si content in the absorber layers (CrAlSiNx/CrAlSiOyNx) of solar selective absorbers upon their selectivity and thermal stability

“…Selective solar thermal absorber coatings are divided into two main groups, the first being based on Cermets as the studied presented in [1][2][3][4] and the second are the metal nitrides and oxynitrides based on structures like the ones presented in [5][6][7]. Cermets allow to obtain efficient absorbers by changing their metal volume fraction to optimize their absorptance and emission [8].…”