Weatherable solar reflector with high abrasion resistance

Patent metadata

Field	Value
Publication number	US-10042094-B2
Application number	US-201114342731-A
Country	US
Kind code	B2
Filing date	Sep 6, 2011
Priority date	Sep 6, 2011
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

Described herein are solar reflectors which provide a low cost reflector construction that has a unique set of attributes: high solar reflectance, abrasion resistance, UV stability, mechanical integrity, and flexibility. The abrasion resistance is enabled through incorporation of an abrasion-resistant coating into a polymer film metal mirror construction. Methods of using the solar reflectors in solar concentrating applications are also provided.

First claim

What is claimed is:

1. A solar reflector comprising:
an abrasion-resistant coating;
a reflective metal layer below the abrasion-resistant coating;
an adhesive layer below the reflective metal layer; and
a polymer film layer;
wherein the polymer film layer is provided between the abrasion-resistant coating and the reflective metal layer, or wherein the polymer film layer is provided between the reflective metal layer and the adhesive layer; and
wherein a hemispherical reflectance of the solar reflector is above 80% for wavelengths between 400 nm and 2200 nm.

2. The solar reflector of claim 1 , wherein the reflective metal layer comprises silver or aluminum.

3. The solar reflector of claim 1 further comprising a protective layer directly below the reflective metal layer.

4. The solar reflector of claim 3 , wherein the protective layer comprises copper, nickel, chrome, a metal alloy, a metal oxide, or any combination of these.

5. The solar reflector of claim 1 , wherein the abrasion-resistant coating comprises an acrylate.

6. The solar reflector of claim 1 , wherein the abrasion-resistant coating comprises ultraviolet absorbers.

7. The solar reflector of claim 1 , wherein the abrasion-resistant coating prevents more than a one percent decrease in specular reflectance of the solar reflector when subjected to 30 cycles of abrasive exposure from a Taber wheel loaded at 250 grams.

8. The solar reflector of claim 1 , wherein the abrasion-resistant coating absorbs less than an average of four percent of electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 400 nanometers to 2,500 nanometers.

9. The solar reflector of claim 1 , wherein the abrasion-resistant coating has a thickness selected over the range of 1 micron to 25 microns.

10. The solar reflector of claim 1 , wherein the abrasion-resistant coating is in physical contact with the polymer film layer.

11. The solar reflector of claim 6 , wherein the abrasion-resistant coating protects the polymer film layer, reflective metal layer, and adhesive layer from damage caused by electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 280 nanometers to 400 nanometers.

12. The solar reflector of claim 6 , wherein the abrasion-resistant coating transmits less than five percent of electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 250 nanometers to 350 nanometers.

13. The solar reflector of claim 6 , wherein the abrasion-resistant coating transmits greater than 33 percent of electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 350 nanometers to 400 nanometers.

14. The solar reflector of claim 1 , wherein the abrasion-resistant coating is the topmost layer of the solar reflector.

15. The solar reflector of claim 1 , wherein the abrasion-resistant coating is provided by gravure, reverse-roll, gap-coating, Meyer rod, slot-die, immersion, curtain, and air-knife application technique.

16. The solar reflector of claim 1 , wherein the adhesive layer comprises a pressure-sensitive adhesive.

17. The solar reflector of claim 1 , wherein the adhesive layer is chemically inert with respect to the reflective metal layer and the protective layer.

18. The solar reflector of claim 1 , wherein the polymer film layer comprises a polyester or polycarbonate.

19. The solar reflector of claim 1 , wherein the polymer film layer comprises ultraviolet absorbers.

20. The solar reflector of claim 19 , wherein the polymer film layer prevents transmission of at least 95 percent of electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 200 nanometers to 380 nanometers.

21. The solar reflector of claim 19 , wherein the polymer film layer transmits at least 96 percent of electromagnetic radiation incident to the solar reflector having wavelengths selected over the range of 380 nanometers to 2500 nanometers.

22. The solar reflector of claim 1 , wherein the polymer film layer has a thickness selected over the range of 10 microns to 150 microns.

23. The solar reflector of claim 1 , wherein the reflective metal layer has a thickness of less than 0.15 micron.

24. The solar reflector of claim 3 , wherein the protective layer has a thickness of less than 0.15 micron.

25. The solar reflector of claim 1 , wherein the adhesive layer has a thickness selected over the range of 5 microns to 100 microns.

26. The solar reflector of claim 1 , wherein a surface of the polymer film layer has been treated by an adhesion promotion technique; and wherein the adhesion promotion technique is a corona discharge, plasma, atomic layer deposition, or chemical etch adhesion promotion technique.

27. The solar reflector of claim 1 , wherein the adhesive layer is provided on a substrate.

28. The solar reflector of claim 1 for use in a concentrating solar, solar tube, light shelf, laminated sheet, or lighting reflector application.

29. A solar reflector comprising:
an abrasion-resistant coating;
a polyester layer directly below the abrasion-resistant coating;
a silver layer directly below the polyester layer;
a copper layer directly below the silver layer; and
an adhesive layer below the silver layer;
wherein the abrasion-resistant coating has a thickness selected over the range of 1 to 25 microns;
wherein the copper layer has a thickness selected over the range of 0.002 micron to 0.15 micron;
wherein the polyester layer comprises polyethylene terephthalate (PET); and
wherein the silver layer has a thickness selected over the range of 0.05 micron to 0.15 micron; and
wherein a hemispherical reflectance of the solar reflector is above 80% for wavelengths between 400 nm and 2200 nm.

30. A solar reflector comprising:
an abrasion-resistant coating;
a silver layer directly below the abrasion-resistant coating;
a copper layer directly below the silver layer;
a polyester layer directly below the copper layer; and
an adhesive layer below the silver layer;
wherein the abrasion-resistant coating has a thickness selected over the range of 1 to 25 microns;
wherein the copper layer has a thickness selected over the range of 0.002 micron to 0.15 micron;
wherein the polyester layer comprises polyethylene terephthalate (PET); and
wherein the silver layer has a thickness selected over the range of 0.05 micron to 0.15 micron; and
wherein a hemispherical reflectance of the solar reflector is above 80% for wavelengths between 400 nm and 2200 nm.

31. The solar reflector of claim 1 , wherein the solar reflector does not comprise an additional acrylic layer between the reflective metal layer and the abrasion-resistant coating.

32. A method of collecting solar radiation, the method comprising:
providing a solar reflector in optical communication with the sun;
providing a target in optical communication with the solar reflector; and
reflecting at least a portion of solar radiation incident on the solar reflector to the target;
wherein the solar reflector comprises:
an abrasion-resistant coating;
a reflective metal layer below the abrasion-resistant coating;
an adhesive layer below the reflective metal layer; and
a polymer film layer;

Assignees

• Gee Randy
• Digrazia Mike
• Jorgensen Gary
• Skyfuel Inc
• Alliance Sustainable Energy

Inventors

• Gee Randy
• Digrazia Mike
• Jorgensen Gary

Classifications

• B32B15/09

  comprising polyesters · CPC title

• F24S23/82

  characterised by the material or the construction of the reflector · CPC title

• B32B2307/416

  Reflective · CPC title

• B32B2307/71

  Resistive to light or to UV · CPC title

• B32B2307/584

  Scratch resistance · CPC title