Lanthanum hexaboride for solar energy applications

Elisa Sani,Luca Mercatelli,Luca Zoli,Marco Meucci,Diletta Sciti

doi:10.1038/s41598-017-00749-w

Elisa Sani, Luca Mercatelli + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-00749-w

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Abstract

We investigate the optical properties of LaB6 – based materials, as possible candidates for solid absorbers in Concentrating Solar Power (CSP) systems. Bulk LaB6 materials were thermally consolidated by hot pressing starting from commercial powders. To assess the solar absorbance and spectral selectivity properties, room-temperature hemispherical reflectance spectra were measured from the ultraviolet to the mid-infrared, considering different compositions, porosities and surface roughnesses. Thermal emittance at around 1100 K has been measured. Experimental results showed that LaB6 can have a solar absorbance comparable to that of the most advanced solar absorber material in actual plants such as Silicon Carbide, with a higher spectral selectivity. Moreover, LaB6 has also the appealing characteristics to be a thermionic material, so that it could act at the same time both as direct high-temperature solar absorber and as electron source, significantly reducing system complexity in future concentrating solar thermionic systems and bringing a real innovation in this field.

Highlights

We investigate the optical properties of LaB6 – based materials, as possible candidates for solid absorbers in Concentrating Solar Power (CSP) systems
From point of view of optical properties, strength points of ultra-high temperature ceramics (UHTCs) materials we have investigated so far are the intrinsic low thermal emittance and good spectral selectivity, while solar absorbance typically is to be improved, e.g. by proper surface treatments[38, 39]
Compared to previously investigated UHTCs, LaB6 has the appealing characteristics to be a thermionic material, so that it could act at the same time both as direct high-temperature solar absorber and as electron source, significantly reducing system complexity in future concentrating solar thermionic systems and bringing a real innovation in this field

Summary

Introduction

We investigate the optical properties of LaB6 – based materials, as possible candidates for solid absorbers in Concentrating Solar Power (CSP) systems. From point of view of optical properties, strength points of UHTC materials we have investigated so far are the intrinsic low thermal emittance and good spectral selectivity, while solar absorbance typically is to be improved, e.g. by proper surface treatments[38, 39].

Results

Conclusion