Solar radiation absorbing material

• US 4,048,980 A
• Filed: 03/08/1976
• Issued: 09/20/1977
• Est. Priority Date: 03/08/1976
• Status: Expired due to Term

• Current Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Original Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Inventors: Schmitt, Charles R., Googin, John M., Schreyer, James M., Whitehead, Harlan D.
• Primary Examiner(s): Camby, John J.
• Assistant Examiner(s): Yuen, Henry C.
• Application Number:
  US05/664,859
• Time in Patent Office: 561 Days
• Field of Search: 126/270, 126/271, 165/133, 138/145
• US Class Current: 126/661
• CPC Class Codes: F24S 70/20 characterised by absorbing coatings; characterised by surface treatment for increasing absorption
• CPC Class Codes: F24S 70/225 for spectrally selective absorption
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y10S 126/907 Absorber coating

Abstract

Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

Claims

1. In a solar collector comprising in combination means for absorbing solar energy from incident solar radiation and means for conducting said energy to a heat transfer medium, the improvement wherein said means for absorbing solar energy is provided with a solar selective surface comprising carbon, said surface having a majority of external pores within the range of about 0.2-2 micrometers.

2. The solar collector of claim 1 wherein said means for absorbing solar energy comprises a thermally conductive substrate and said solar selective surface comprises a solar selective array of carbon particles in a binder for adhering said carbon particles together and to said thermally conductive substrate.

3. The solar collector of claim 2 wherein a majority of said carbon particles have diameters within the range of about 0.2-10 micrometers.

4. The solar collector of claim 2 wherein said carbon particles have been fired to above 1900°

C.

7. The solar collector of claim 2 wherein said carbon particles have a majority of external pores within the range of about 0.2-2 micrometers.

8. The solar collector of claim 7 wherein said carbon particles have been fired to above 1900°

C.

5. A method of providing a thermally conductive substrate with a selective solar energy absorbing coating, said method comprising adhering a coating comprising carbon particles to said surface, a majority of said carbon particles having diameters within the range of 0.2-10 micrometers.

6. The method of claim 5 wherein said carbon particles are fired to above 1900°

C.

9. A method of providing a thermally conductive substrate with a selective solar energy absorbing coating, said method comprising adhering a coating comprising carbon particles to said surface, said carbon particles having a majority of external pores within the range of about 0.2-2 micrometers.

10. The method of claim 9 wherein said carbon particles are fired to above 1900°

C.