Broadband reflectors, concentrated solar power systems, and methods of using the same

• US 9,523,516 B2
• Filed: 12/21/2009
• Issued: 12/20/2016
• Est. Priority Date: 12/30/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Chen, Daniel Ting-Yuan, Hebrink, Timothy J., Clear, Susannah C., Gilbert, Laurence R., Weber, Michael F., Yu, Ta-Hua, Sherman, Audrey A.
• Primary Examiner(s): Chen, Vivian
• Application Number:
  US13/142,910
• Publication Number:
  US 20120011850A1
• Time in Patent Office: 2,556 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/082 comprising vinyl resins; comprising acrylic resins
• CPC Class Codes: B32B 15/085 comprising polyolefins
• CPC Class Codes: B32B 15/088 comprising polyamides
• CPC Class Codes: B32B 15/09 comprising polyesters
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2250/42 Alternating layers, e.g. ABAB(C), AABBAABB(C)
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/205 Metallic coating
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2311/08 Silver
• CPC Class Codes: B32B 2311/12 Copper
• CPC Class Codes: B32B 2311/24 Aluminium
• CPC Class Codes: B32B 2311/30 Iron, e.g. steel
• CPC Class Codes: B32B 2323/00 Polyalkenes
• CPC Class Codes: B32B 2325/00 Polymers of vinyl-aromatic compounds, e.g. polystyrene
• CPC Class Codes: B32B 2327/00 Polyvinylhalogenides
• CPC Class Codes: B32B 2331/00 Polyvinylesters
• CPC Class Codes: B32B 2333/12 Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate
• CPC Class Codes: B32B 2367/00 : Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 2377/00 : Polyamides
• CPC Class Codes: B32B 2383/00 : Polysiloxanes
• CPC Class Codes: B32B 2551/00 : Optical elements
• CPC Class Codes: B32B 2551/08 : Mirrors
• CPC Class Codes: B32B 27/283 : comprising polysiloxanes
• CPC Class Codes: B32B 27/302 : comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
• CPC Class Codes: B32B 27/304 : comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/306 : comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/308 : comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/325 : comprising polycycloolefins
• CPC Class Codes: B32B 27/34 : comprising polyamides
• CPC Class Codes: B32B 27/36 : comprising polyesters
• CPC Class Codes: B32B 7/023 : Optical properties
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: F03G 6/06 : with solar energy concentrating means
• CPC Class Codes: F03G 6/061 : Parabolic linear or trough concentrators
• CPC Class Codes: F03G 6/063 : Tower concentrators
• CPC Class Codes: F24S 10/00 : Solar heat collectors using working fluids
• CPC Class Codes: F24S 10/70 : the working fluids being conveyed through tubular absorbing conduits
• CPC Class Codes: F24S 20/00 : Solar heat collectors specially adapted for particular uses or environments
• CPC Class Codes: F24S 20/20 : Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
• CPC Class Codes: F24S 2023/87 : Reflectors layout
• CPC Class Codes: F24S 2025/601 : by bonding, e.g. by using adhesives
• CPC Class Codes: F24S 2030/136 : for moving several solar collectors by common transmission elements
• CPC Class Codes: F24S 2030/16 : Hinged elements; Pin connections
• CPC Class Codes: F24S 23/00 : Arrangements for concentrating solar-rays for solar heat collectors
• CPC Class Codes: F24S 23/70 : with reflectors
• CPC Class Codes: F24S 23/74 : with trough-shaped or cylindro-parabolic reflective surfaces
• CPC Class Codes: F24S 23/77 : with flat reflective plates
• CPC Class Codes: F24S 23/82 : characterised by the material or the construction of the reflector
• CPC Class Codes: F24S 30/425 : Horizontal axis
• CPC Class Codes: F24S 50/20 : for tracking
• CPC Class Codes: G02B 17/006 : Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08
• CPC Class Codes: G02B 19/0019 : having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
• CPC Class Codes: G02B 19/0042 : for use with direct solar radiation
• CPC Class Codes: G02B 5/0841 : comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 6/0011 : the light guides being planar or of plate-like form
• CPC Class Codes: H01L 31/0547 : comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: H02S 20/00 : Supporting structures for PV modules
• CPC Class Codes: Y02E 10/40 : Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/44 : Heat exchange systems
• CPC Class Codes: Y02E 10/46 : Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines
• CPC Class Codes: Y02E 10/47 : Mountings or tracking
• CPC Class Codes: Y02E 10/52 : PV systems with concentrators
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/3154 : Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31681 : Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31692 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/3175 : Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/31757 : Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31909 : Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31913 : Monoolefin polymer
• CPC Class Codes: Y10T 428/31928 : Ester, halide or nitrile of addition polymer

Abstract

Broadband reflectors include a UV-reflective multilayer optical film and a VIS/IR-reflective layer. In various embodiments, the VIS/IR reflective layer may be a reflective metal layer or a multilayer optical film. Concentrated solar power systems and methods of harnessing solar energy using the broadband reflectors and optionally comprising a celestial tracking mechanism are also disclosed.

Claims

1. A broadband reflector comprising:

a UV-reflective multilayer optical film having a first major surface and comprising a UV-reflective optical layer stack, wherein the UV-reflective optical layer stack comprises first optical layers and second optical layers, wherein at least a portion of the first optical layers and at least a portion of the second optical layers are in intimate contact and have different refractive indexes, wherein the first optical layers comprise a first polymer and the second optical layers comprise a second polymer, and wherein neither the first polymer nor the second polymer absorb UV light in a wavelength range from 350 nanometers to 400 nanometers; and

a VIS/IR-reflective metal layer disposed on at least a portion of the first major surface.

2. The broadband reflector of claim 1, further comprising an adhesive layer disposed on the metal layer opposite the UV-reflective multilayer optical film.

3. The broadband reflector of claim 1, wherein the VIS/IR-reflective metal layer comprises at least one of silver, copper, stainless steel, or aluminum.

4. The broadband reflector of claim 1, wherein at least one of the following conditions is met:

the broadband reflector has an average light reflectivity of 90 percent over a wavelength range of 300 to 400 nanometers;

or

the broadband reflector has an average light reflectivity of at least 95 percent over a wavelength range of 350 to 2494 nanometers.

5. A concentrated solar power system comprising:

at least one broadband reflector according to claim 1 capable of being aligned to direct solar radiation onto a hollow receiver; and

a heat transfer fluid partially disposed within the hollow receiver.

6. The concentrated solar power system of claim 5, further comprising an electrical generator in fluid communication with the hollow receiver.

7. The concentrated solar power system of claim 5, further comprising a celestial tracking mechanism for the at least one broadband reflector.

8. The concentrated solar power system of claim 7,

wherein the celestial tracking mechanism comprises a louver pivotally mounted adjacent the hollow receiver, wherein the louver comprises the at least one broadband reflector.

9. A method of harnessing solar energy, the method comprising reflecting solar radiation using at least one broadband reflector according to claim 1 onto a hollow receiver containing a heat transfer fluid to provide a heated heat transfer fluid.

10. A method of using the broadband reflector of claim 1, the method comprising:

adhering the broadband reflector to an existing solar reflector adapted for use in a concentrated solar power system.

11. The broadband reflector of claim 1, wherein the UV-reflective multilayer optical film further comprises a tie layer that comprises the first major surface of the UV-reflective multilayer optical film.

12. The broadband reflector of claim 1, wherein the UV-reflective multilayer optical film further comprises a second major surface opposite the first major surface, and wherein the UV-reflective multilayer optical film further comprises an abrasion resistant layer that forms the second major surface of the UV-reflective multilayer optical film.

13. The broadband reflector of claim 1, wherein the UV-reflective multilayer optical film also reflects visible light.

14. A broadband reflector comprising:

a UV-reflective multilayer optical film having a first major surface and comprising a UV-reflective optical layer stack, wherein the UV-reflective optical layer stack comprises first optical layers and second optical layers, wherein at least a portion of the first optical layers and at least a portion of the second optical layers are in intimate contact and have different refractive indexes; and

a VIS/IR-reflective metal layer disposed on at least a portion of the first major surface, wherein;

(i) the first optical layers comprise a syndiotactic polystyrene and the second optical layers comprise a polydiorganosiloxane polyoxamide block copolymer;

or

(ii) the first optical layers comprise a syndiotactic polystyrene and the second optical layers comprise a copolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride;

or

(iii) the first optical layers comprise a polymethyl methacrylate and the second optical layers comprise a copolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride;

or

(iv) the first optical layers comprise a copolymer of ethylene and a cyclic olefin and the second optical layers comprise a copolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride;

or

(iv) the first optical layers comprise a copolymer of ethylene and vinyl acetate and the second optical layers comprise a copolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.

15. The broadband reflector of claim 14, wherein at least one of the following conditions is met:

the broadband reflector has an average light reflectivity of 90 percent over a wavelength range of 300 to 400 nanometers;

or

the broadband reflector has an average light reflectivity of at least 95 percent over a wavelength range of 350 to 2494 nanometers.

16. The broadband reflector of claim 14, wherein the UV-reflective multilayer optical film further comprises a second major surface opposite the first major surface, and wherein the UV-reflective multilayer optical film further comprises an abrasion resistant layer that forms the second major surface of the UV-reflective multilayer optical film.

17. The broadband reflector of claim 14, wherein the UV-reflective multilayer optical film also reflects visible light.

18. A concentrated solar power system comprising:

at least one broadband reflector according to claim 14 capable of being aligned to direct solar radiation onto a hollow receiver; and

a heat transfer fluid partially disposed within the hollow receiver.

19. The broadband reflector of claim 14, further comprising an adhesive layer disposed on the metal layer opposite the UV-reflective multilayer optical film.

20. The broadband reflector of claim 14, wherein the VIS/IR-reflective metal layer comprises at least one of silver, copper, stainless steel, or aluminum.