Optimizing effectiveness and robustness for solar heat absorbers composed of a periodically nano-structured surface

Abstract

This work studies solar heat absorbers having periodic and rectangular nano-pillars on their surfaces. Design factors are periods, filling ratios, and pillar height. They are tailored using the design of experiments for absorption effectiveness and robustness. The former requires enlarging absorption within the solar spectrum as well as diminishing re-emission loss at long wavelengths. The latter refers to independence of absorption effectiveness from noise interference. Studied noise factors include dimensional deviations and variation of sunlight orientation. Effects from individual design factor and interactions between two design factors are all investigated. The selected absorbers exhibit appealing wavelengthselective absorptance spectra. Absorption effectiveness and robustness of these absorbers are quantitatively illustrated by a large response variable Q and its small variation S, respectively.