Selective coating for solar panels
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorGlen E. McDonald
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Abstract
The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.
Claims8
In apparatus for collecting solar energy of the type having a composite heating panel for absorbing said solar energy and converting the same to heat, the improvement comprising
- a metallic substrate forming a high conductivity base for said panel, said substrate having at least one surface exposed to said solar energy,
- a layer of dull nickel on said one surface to lower the emissivity of said surface, and
- a coating of black chrome on said layer of dull nickel, said coating having a thickness between about 0.5 micron and about 2.5 microns and being highly absorbtive in the visible range.
A method of making a composite heating panel for a solar collector comprising the steps of
- depositing a layer of dull nickel to a thickness of about 0.0005 inch on a surface of a high thermal conductivity substrate to lower the emissivity thereof, and
- coating said layer of dull nickel with black chrome to a thickness between about 0.5 micron and about 2.5 microns to raise the absorbtivity of said surface in the visible range.
Dependencies are inferred from the claim text.