Solar Thermal Energy Conversion Enhanced by Selective Metafilm Absorber under Multiple Solar Concentrations at High Temperatures

TL;DR

This study demonstrates a multilayer metafilm absorber with high spectral selectivity and thermal stability that significantly improves solar-thermal conversion efficiency at high temperatures and multiple solar concentrations.

Contribution

The paper introduces a novel multilayer metafilm absorber that outperforms black absorbers in efficiency and stability for high-temperature solar thermal applications.

Findings

Achieved 57% efficiency at 371°C under 10 suns in lab tests.

Projected 83% efficiency for practical applications.

Demonstrated superior spectral selectivity and thermal stability.

Abstract

Concentrating solar power, particularly parabolic trough system with solar concentrations less than 50, requires spectrally selective solar absorbers that are thermally stable at high temperatures of 400degC above to achieve high efficiency. In this work, the solar-thermal performance of a selective multilayer metafilm absorber is characterized along with a black absorber for comparison by a lab-scale experimental setup that measures the steady-state absorber temperature under multiple solar concentrations. Heat transfer analysis is employed to elucidate different heat transfer modes and validate the solar-thermal experiment. Due to the superior spectral selectivity and excellent thermal stability, the metafilm absorber deposited on the cost-effective stainless steel foil could achieve the solar-thermal efficiency 57% at a steady-state temperature of 371degC under 10 suns during the lab-scale experiment with losses, while a highest efficiency of 83% was projected under the same conditions for practical solar thermal applications. The results here will facilitate the research and development of novel solar materials for high-efficiency solar thermal energy conversion.