Absorbent material and solar panel using such a material

Patent metadata

Field	Value
Publication number	US-9671137-B2
Application number	US-201414776147-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 15, 2013
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

The invention concerns a multilayer material comprising at least:
a support having a reflectance R higher than 80% for radiations of wavelengths higher than 5 μm, a selective layer comprising a combination of Vanadium oxides VO 2 and VO 2 O 2n+/−1 , with n>1, said selective layer having an absorbance higher than 75% for radiations of wavelengths comprised between 0.4 and 2.5 μm, regardless of the temperature T, and having, for radiations of wavelengths comprised between 6 and 10 μm, a transmittance Tr such that:
Tr>85% for T<Tc, a critical temperature, 20%≦Tr≦50% for T>Tc.

Application to the production of thermal solar panels having a low stagnation temperature and high performance.

First claim

The invention claimed is:

1. A multilayer material comprising at least:
a support having a reflectivity R higher than 80% for radiations of wavelengths higher than 5 μm,
a selective layer having a thickness comprised between 100 and 500 nm, said selective layer comprising a combination of vanadium oxides VO 2 and V n O 2n+/−1 , with n>1, said selective layer having an absorbance higher than 75% for radiations of wavelengths comprised between 0.4 and 2.5 μm, regardless of the temperature T, and having, for radiations of wavelengths comprised between 6 and 10 μm, a transmittance Tr such that:
Tr>85% for T<Tc, a critical temperature,
20%≦Tr≦50% for T>Tc,

wherein, for radiations of wavelengths comprised between 6 and 10 μm, the support has an optical index n1 and the selective layer has an optical index n2 such that:
n2<n1 regardless of the temperature T, and
n2<6 T>Tc.

2. Material according to claim 1 , wherein the selective layer has an extinction coefficient k lower than 4 for radiations of wavelengths comprised between 6 and 10 μm.

3. Material according to claim 1 , wherein, for radiations of wavelengths between 6 and 10 μm, the optical index n2 is comprised between 0.8*(n1) 1/2 and 1.2*(n1) 1/2 for T>Tc.

4. Material according to claim 1 , wherein the selective layer has a thickness comprised between 100 and 200 nm.

5. Material according to claim 1 , wherein the selective layer is doped with at least one metal M different from Vanadium.

6. Material according to claim 5 , wherein the selective layer is doped with aluminum and has a critical temperature comprised between 80° C. and 120° C.

7. Material according to claim 5 , wherein the selective layer has a concentration in the dopant M sufficient to form at least one oxide of the form M 1-x O x , with 0<x<1, x being the atomic fraction of oxygen in the oxide, so that the selective layer comprises a combination of oxides of the type VO 2 , V n O 2n+/−1 , and M 1-x O x .

8. Material according to claim 7 , wherein the oxide or oxides in the form M 1-x O x have a transmittance higher than 85% for infrared radiations whose wavelengths are comprised between 6 and 10 μm.

9. Material according to claim 8 , wherein the oxide of the form M 1-x O x is an aluminum oxide.

10. Material according to claim 1 , wherein the selective layer is covered with an antireflection layer having, for radiations whose wavelengths are comprised between 0.4 and 2.5 μm, an optical index n3<n2, n2 being the optical index of the selective layer.

11. Material according to claim 10 , wherein the antireflective layer has a thickness comprised between 10 and 150 nm.

12. Material according to claim 1 , further comprising, between the selective layer and the support, an adhesive layer, for example, a metal layer, an oxide layer, a layer of transition metal nitrides, or a layer of a mixture of these materials, having a thickness comprised between 5 and 100 nm.

13. Material according to claim 1 , wherein the selective layer comprises:
a combination of VO 2 and V 4 O 9 Vanadium oxides, or
a combination of VO 2 and V 6 O 13 Vanadium oxides, or
a combination of VO 2 and V 4 O 9 Vanadium oxides and Al 2 O 3 oxide.

14. Solar panel comprising a multilayer material according to claim 1 .

15. Material according to claim 2 , wherein, for radiations of wavelengths between 6 and 10 μm, the optical index n2 is comprised between 0.8*(n1) 1/2 and 1.2*(n1) 1/2 for T>Tc.

16. Material according to claim 5 , wherein the at least one metal M is aluminum, chromium, or titanium.

17. Material according to claim 8 , wherein the oxide of the form M 1-x O x is Al 2 O 3 .

18. Material according to claim 8 , wherein the oxide of the form M 1-x O x is an under-stoichiometric aluminum oxide.

19. A multilayer material comprising at least:
a support having a reflectivity R higher than 80% for radiations of wavelengths higher than 5 μm,
a selective layer having a thickness comprised between 100 and 500 nm, said selective layer comprising a combination of vanadium oxides VO 2 and V n O 2n+/−1 , with n>1, said selective layer having an absorbance higher than 75% for radiations of wavelengths comprised between 0.4 and 2.5 μm, regardless of the temperature T, and having, for radiations of wavelengths comprised between 6 and 10 μm, a transmittance Tr such that:
Tr>85% for T<Tc, a critical temperature,
20%≦Tr≦50% for T>Tc,

wherein the selective layer is covered with an antireflection layer having, for radiations whose wavelengths are comprised between 0.4 and 2.5 μm, an optical index n3<n2, n2 being the optical index of the selective layer.

20. Material according to claim 19 , wherein the antireflective layer has a thickness comprised between 10 and 150 nm.

Assignees

• Viessmann Faulquemont
• Centre Nat Rech Scient
• Univ De Lorraine

Inventors

• Mercs David
• Capon Fabien
• Corvisier Alan

Classifications

• C23C14/083

  of refractory metals or yttrium · CPC title

• C23C14/0641

  Nitrides (C23C14/0617 takes precedence) · CPC title

• G02B5/208

  for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation · CPC title

• F24S70/30

  Auxiliary coatings, e.g. anti-reflective coatings · CPC title

• Y02E10/40

  Solar thermal energy, e.g. solar towers · CPC title