Volume 39: Energy Transitions toward Carbon Neutrality: Part II

Hemispherical Emittance in Multilayer Solar Absorbers: A MATLAB-Based Approach for Optimizing Solar Thermal Efficiency Eliana Gaudino, Antonio Caldarelli, Daniela De Luca, Umar Farooq, Paolo Strazzullo, Emiliano Di Gennaro, Marilena Musto, Roberto Russo

Abstract

The thermal emissivity of selective solar absorbers is a critical determinant of their operational efficiency. This paper details the computation of hemispherical emissivity for multi-layered coatings, specifically designed and optimized for solar thermal applications, particularly within high vacuum flat collectors at temperatures up to 200°C. We employed a MATLAB script, underpinned by the transfer matrix method, to calculate the hemispherical emissivity. The calculated emissivity values aligned well with experimental measurements derived from sputter-deposited samples. Our findings underscore the efficacy of the designed multi-layered coatings in relation to their thermal emissivity characteristics, thus highlighting their potential for solar thermal applications.

Keywords solar thermal, solar energy, solar absorbers, multilayer coatings characterization, evacuated solar thermal collectors