US 8,893,711 B2 · High temperature solar selective coatings

Abstract

Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti3SiC2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO2, Ti3O5. TiOx or TiOxN1-x with x 0 to 1. The silica can be at least one of SiO2, SiO2x or SiO2xN1-x with x=0 to 1.

Claims20

Dependent claims

A method for manufacturing a solar selective absorption material, comprising:

providing a substrate ;
applying thereto at least one layer of at least one IR reflective material;
applying to said at least one layer of the at least one IR reflective material at least one layer of at least one solar absorbent material including depositing materials to form said at least one solar absorbent material as a cermet;
and
applying at least one surface layer of at least one solar antireflective material, to produce a coated substrate having an overall high solar absorbance and a low IR emittance at elevated temperatures,
wherein the at least one solar absorbent cermet comprising the deposited materials comprises particles of at least one first metal in the form of a metal silicide, an elemental metal, and mixtures thereof dispersed in the solar absorbent material, wherein the at least one solar absorbent material comprises at least one second metal in the form of a metal oxide, a metal nitride, a metal oxynitride, a metal silicide, a metal boride, a metal carbide, a metal ternary compound, and mixtures thereof,
wherein the at least one first metal of the particles comprises at least one of a Group IVA metal, a Group VA metal, a Group VI metal, a noble metal, and mixtures thereof, and
wherein the at least one second metal of the solar absorbent material comprises at least one of a Group IVA metal, a Group VA metal, a Group VI metal, a metalloid, a noble metal, and mixtures thereof
wherein the high solar absorbance is greater than about 0.96.

6 more elements

Dependencies are inferred from the claim text.

High temperature solar selective coatings

Life of this patent

High temperature solar selective coatings

Life of this patent

Abstract

Claims20