| Heat utilization of solar energy has been researched widely in our country nearly30years. Solar thermal hair as the most promising will undoubtedly become the focus of hotspots. Selective absorbing coating is a key material affecting the thermal efficiency of thesolar thermal collectors. It is a function film converting solar energy to heat directly, so toimprove the selective absorption performance has become the key.This paper introduces the significance of this research, history and the status quo of thesolar spectral selective absorbing coating in detail. Starting from the principle of selectiveabsorption, combined with previous work experience summary to selected materials andmembrane system structure, and using the Mathematica software program to optimize anddesign the film system parameters. Get to better selective absorption performance of coatingand more simple and effective optimization method, the experimental preparation of coatingprovide certain theoretical guidance and practical production. The research content specific asfollows:W-AlN metal-dielectric selective absorbing coatings were studied as tungsten thin filmwas chosen as the reflector. The volume fractions of W and thickness of absorbing coatingsand decreased layer were optimized and calculated by using Mathematica software.Optimization results show that the selective absorbing properties of the coatings has beendirect influenced by the volume fractions of W in the absorbing coatings; While, comparedwith the thickness of the low metal volume fraction absorbed layer, the thickness of highmetal volume fraction absorbed layer on the properties of selective absorbing was smaller.Optimal volume fractions of W in the low/high metal volume fraction absorbed layers were0.2/0.8, respectively, and the optimal thickness were0.1μm/0.05μm. The absorptivity of thecoating is0.841, the emissivity is0.021. After join the0.06μm AlN decreased layer, theabsorption rate is0.9195and the emission rate is0.0223. |
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