HIGH TEMPERATURE SOLAR SELECTIVE COATINGS
First Claim
1. A method for manufacturing a solar selective absorption material, characterized essentially by the following steps:
- a) providing a substrate comprising an infrared reflecting metal;
b) applying thereto a layer of an IR reflective material;
c) applying to said layer of IR reflective material at least one layer of a solar absorbent material;
d) optionally, applying to said layer of solar absorbent material another layer of IR reflective material, followed by another layer of solar absorbent material, which steps can be repeated; and
e) applying at least one surface layer of solar antireflective material, to produce a coated substrate having overall high Solar absorbance and low IR emittance at elevated temperatures.
2 Assignments
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Accused Products
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 SiO2x, SiO2x or SiO2xN1−x with x=0 to 1.
130 Citations
23 Claims
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1. A method for manufacturing a solar selective absorption material, characterized essentially by the following steps:
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a) providing a substrate comprising an infrared reflecting metal; b) applying thereto a layer of an IR reflective material; c) applying to said layer of IR reflective material at least one layer of a solar absorbent material; d) optionally, applying to said layer of solar absorbent material another layer of IR reflective material, followed by another layer of solar absorbent material, which steps can be repeated; and e) applying at least one surface layer of solar antireflective material, to produce a coated substrate having overall high Solar absorbance and low IR emittance at elevated temperatures. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 21, 22, 23)
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16. A solar selective coated substrate comprising an infrared reflecting substrate, at least one layer of solar absorbent material and at least one layer of antireflective material, characterized by:
- a substrate comprising stainless steel, a plurality of layers of solar absorptive material comprising at least one refractory metal oxide, nitride or oxynitride and a plurality of layers of IR reflective material comprising at least one refractory metal silicide, boride or carbide, topped with at least one layer of solar antireflective material comprising at least one layer of a refractory metal oxide and at least one layer of a silica, producing a material having high solar absorptance and low IR emittance at elevated temperatures.
- View Dependent Claims (17, 18)
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19. The coated substrate is characterized by a top layer of antireflective material which is texturized to increase solar absorption and minimize surface reflection. Wherein said top layer of antireflective material is characterized by comprising at least one silica having a low index of refraction.
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20. A solar absorbent coaled substrate comprising an infrared reflecting substrate, at least one layer of solar absorbent material and at least one layer of antireflective material, characterized by a reflective substrate comprising stainless steel, at least two solar absorbent layers of cermet materials comprising particles of titanium silicide in a matrix comprising at least one refractory metal or metalloid oxide, each layer of said cermet material having either a high or low index of refraction and a differing volume fraction of said titanium silicide expressed as metal to the metal oxide matrix and an outer antireflective layer comprising at least one layer of titanium dioxide having a high index of refraction adjacent to at least one layer of silica having a low index of refraction.
Specification