A CORRUGATED TRANSPARENT TOP PANEL FOR EITHER INCREASING OR DECREASING HARVESTING OF SOLAR RADIATION AND METHODS THEREOF

Abstract

The present invention generally pertains to a corrugated transparent top panel provided useful for either increasing or decreasing harvesting of solar radiation and to methods thereof. A special use of this panel is in photovoltaic cells, solar cells, walls, windows and agricultural structures.

Claims

1.-11. (canceled)

12. A transparent top panel (100) useful for providing a favorable incident angle for solar light at the exterior surface of a photovoltaic or solar cell, said transparent top panel comprising an exterior surface, having a layer configured for scattering and diffracting a solar light being incident thereto; wherein said layer comprises distance-d.sub.1-spaced primary corrugations made of at least one first transparent composition; said primary corrugations further comprising distance-d.sub.2-spaced secondary corrugations made of at least one second transparent composition by means of varying of a thickness or a refractive index thereof within said primary corrugations; said first distance d.sub.1 being at least 5 times said second distance d.sub.2; said secondary corrugations further comprising distance d.sub.3-spaced tertiary corrugations made of at least one third transparent composition by means of varying of a thickness or a refractive index thereof within said secondary corrugations; said second distance d.sub.2 being at least 5 times said third distance d.sub.3; wherein said primary corrugations form a regular, evenly-spaced pattern on said substrate, said secondary corrugations form a regular, evenly-spaced pattern on said primary corrugations and said tertiary corrugations form a regular, evenly-spaced pattern on said secondary corrugations; further wherein a cross-section of said tertiary corrugations comprises a plurality of different slopes; and said corrugations each comprise a base with a two-dimensional shape.

13. The transparent top panel (100) of claim 12, wherein a first shape of said primary corrugations is selected from a group consisting of circular cross-section, ellipsoidal cross-section and lenticular.

14. The transparent top panel (100) of claim 12, wherein a second shape of said primary corrugations is selected from a group consisting of tubular, cubic, truncated rectangular pyramid, spherical, and ellipsoidal.

15. The transparent top panel (100) of claim 12, wherein a first shape of said secondary corrugations is selected from a group consisting of circular cross-section, ellipsoidal cross-section and lenticular.

16. The transparent top panel (100) of claim 12, wherein a second shape of said secondary corrugations is selected from a group consisting of tubular, cubic, truncated rectangular pyramid, spherical, and ellipsoidal.

17. The transparent top panel (100) of claim 12, wherein a first shape of said tertiary corrugations is selected from a group consisting of circular cross-section, ellipsoidal cross-section and lenticular.

18. The transparent top panel (100) of claim 12, wherein a second shape of said tertiary corrugations is selected from a group consisting of tubular, cubic, truncated rectangular pyramid, spherical, and ellipsoidal.

19. The transparent top panel (100) of claim 12, wherein at least one of the following is true: a cross-section of a member of a group consisting of said primary corrugations, said secondary corrugations and any combination thereof comprises a plurality of different slopes; and at least a portion of a cross-section of a member of a group consisting of said primary corrugations, said secondary corrugations, said tertiary corrugations and any combination thereof is curved.

20. A transparent top panel (100) for providing a selected range of incident angles at which solar light is perpendicular to the exterior surface of a photovoltaic or solar cell; wherein a layer of said panel comprises distance-d.sub.1-spaced primary, substantially sinusoidal corrugations of magnitude M.sub.1; said primary corrugations further comprising distance-d.sub.2-spaced secondary, substantially sinusoidal corrugations of magnitude M.sub.2; said secondary corrugations further comprising distance d.sub.3-spaced tertiary, substantially sinusoidal corrugations of magnitude M.sub.3; wherein d.sub.3<d.sub.2<d.sub.1; and one or more parameters comprising distance ratios d.sub.1:d.sub.2 and d.sub.1:d.sub.3 are configured for a selected said range of incident angles.

21. The panel of claim 20, wherein said spacing ratio d.sub.1:d.sub.2 is at least about 5 and said spacing ratio d.sub.1:d.sub.3 is at least about 25.

22. The panel of claim 20, wherein said parameters configured for a said chosen range of incident angles further comprise the magnitude ratios M.sub.1:M.sub.2 and M.sub.1:M.sub.3.

23. The panel of claim 22, wherein said magnitude ratios are further selected for an amount of absorption by multiple reflections.

24. The panel of claim 20, at least partially provided in a gas phase, liquid phase, solid phase and any mixture or combination thereof.

25. The panel of claim 20, made of flexible material, semi-flexible material or inflexible material.

26. The panel of claim 20, made of polymer(s), glass(es), sol(s), gel(s), sol-gel(s), composite material(s) and any mixture or combination thereof.

27. The panel of claim 20, wherein said panel comprises a first surface and a second opposite surface said second surface is interconnected with or otherwise comprises an adhesive, glue or fixating means.

28. The panel of claim 20, wherein said distances d.sub.1, d.sub.2, and d.sub.3 are on a macro-, micro-, or nano-scale.

29. A method for providing a favorable incident angle for solar light at the exterior surface of a photovoltaic or solar cell, said method comprising steps of providing a transparent top panel (100) of claim 12.

30. A transparent top panel (100) useful for providing a favorable incident angle for solar light at the exterior surface of a photovoltaic or solar cell, said transparent top panel comprising an exterior surface, having a layer configured for scattering and diffracting a solar light being incident thereto; wherein said layer comprises primary, secondary and tertiary corrugations made of at least one first transparent composition; said primary corrugations further comprising secondary corrugations made of at least one second transparent composition by means of varying of a thickness or a refractive index thereof within said primary corrugations; said secondary corrugations further comprising tertiary corrugations made of at least one third transparent composition; at least a portion of said corrugations comprises a base with a two-dimensional shape.

31. A method for providing a favorable incident angle for solar light at the exterior surface of a photovoltaic or solar cell, said method comprising steps of providing a transparent top panel (100) of claim 30.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects of the present teachings and together with the description, serve to explain principles of the present teachings. In the figures:

[0049] FIG. 1 illustrates schematically and in an out-of-scale manner an upper surface of either a photovoltaic cell or solar cell (1) according to one embodiment of the invention;

[0050] FIG. 2 schematically and in an out-of-scale manner illustrates in a non-limiting manner several embodiments of corrugated transparent panel (100) according to another embodiment of the invention;

[0051] FIG. 3 schematically and in an out-of-scale manner illustrates in a non-limiting manner embodiment of secondary and tertiary corrugated transparent panels (100) according to other embodiments of the invention;

[0052] FIG. 4 schematically and in an out-of-scale manner illustrates in a non-limiting manner several embodiments of the macro, micro or nano structures according to another embodiment of the invention;

[0053] FIG. 5 schematically and in an out-of-scale manner illustrates in a non-limiting manner several embodiments of the macro-, micro- or nano-structures according to another embodiment of the invention;

[0054] FIGS. 6 and 7 disclose a half-bubble-like microsphere (124) and light projecting/intensifying glass-like lens-like macro-structure (125) according to yet other embodiments of the invention; and

[0055] FIGS. 8 and 9 disclose a solar/photovoltaic cell with panel (126) and greenhouse with panel (127) according to yet other embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] Reference will now be made in detail to implementations of the present teachings, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0057] In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific implementations in which may be practiced. These implementations are described in sufficient detail to enable those skilled in the art to practice these implementations and it is to be understood that other implementations may be utilized and that changes may be made without departing from the scope of the present teachings. The following description is, therefore, merely exemplary.

[0058] The present invention generally pertains to a corrugated transparent top panel provided useful for either increasing or decreasing harvesting of solar radiation and to methods thereof. A special use of this panel is in photovoltaic cells, solar cells, windows, walls and agricultural structures.

[0059] The technology of the present invention is provided useful in various industries and utilizations, including, inter alia, coatings, film, patch, window shade that are widely used in all forms of human endeavor. Examples include commercial, industrial, medical, personal, residential and social. Industrial coatings, treatments and paint are used in many applications such as building interiors/exteriors, computers, consumer electronic devices, cosmetics, electrical, fabrics, furniture, home appliances, infrastructure, internal and/or external structural surfaces, luxury goods, telecommunications, mechanical and industrial equipment, media, medical devices and medical supplies. In addition to aesthetics of appearance, color, decoration, design and finish coatings are used for protection e.g. impermeability, hydrophobicity, shielding and resistance to electromagnetic, radio frequency, ultraviolet or other radiation. The acquisition of raw materials, manufacture production, transportation and application of such coatings consumes enormous amounts of energy and produces even greater volumes of greenhouse gasses, toxic waste products and other harmful emissions. Conventional coatings contain a high proportion of toxic materials and petrochemical products or derivatives. In the last half-century titanium and other metal oxides have been identified as possessing particular light scattering/absorbing properties. Such materials have been incorporated into many of these coatings.

[0060] This technology is provided for use in a variety of sectors and structural forms e.g. automotive, aviation, construction, engineering, transportation, etc. will realize substantial economic and ecological benefits. The invention described herein provides a method to influence temperature-dependent heat transport by modifying spectral emissivity and other features. The method concerns the engineering of active/passive wavelength and temperature dependent tunable coatings.

[0061] FIG. 1 illustrates schematically and in an out-of-scale manner an upper surface of either a photovoltaic cell or solar cell (1), optionally tilted southwards. In this embodiment, at least corrugated transparent panel (100), made of e.g., glass or polymers (PMMA, poly carbonate etc.) provides as the top of cell (1). Its curves are configured to maximize absorption of solar irradiation. Hence, in early mornings, when sun rises (E), eastern slopes faces light (12); whilst at sunset, light (11) from western sun (W) faces western slopes. Midday, when sun set (10) up above, concaved/convex panel maximize harvesting of solar energy.

[0062] Reference is now made to FIG. 2A-C, schematically and in an out-of-scale manner illustrating in a non-limiting manner several embodiments of corrugated transparent panel (100). As schematically illustrated in FIG. 2A, the sinusoidal or otherwise evenly or non-evenly waved surface of cross section 101 comprises a lower portion (1015) and a higher portion (1014). This waved, oscillating or fluted-wave one or more portion of the panel is characterized by either stiff walls (cross section, FIG. 2B, 102) or slim walls (perspective front view, FIG. 2C, 103), where minimum lines and maximum lines are either perpendicular to the continuous sine wave (see FIG. 2A, lines 1014 and 1015) or at least partially tilted (e.g., linearly, curved or rounded) to its main perpendicular axis

[0063] Reference is now made to FIG. 3A-D, where FIG. 3C schematically and in a non-limiting and out-of-scale manner illustrates a cross-section of a surface (100) of a transparent panel comprising a single sinusoid (204), FIG. 3A schematically and in a non-limiting and out-of-scale manner illustrates a cross-section of a surface (100) of a transparent panel with secondary sinusoidal corrugations (105) provided upon a primary sinusoidal wave (204), and FIGS. 3B and 3D schematically and in a non-limiting and out-of-scale manner illustrate a cross-section of a surface (100) of a transparent panel comprising secondary and tertiary sinusoidal corrugations (106) upon a primary sinusoidal wave (204).

[0064] If the surface is curved or otherwise comprises a plurality of angles relative to a plane comprising an average height of the surface, the angle between a perpendicular to the surface and the sun will be different on different positions on the surface. This is indicated schematically for a single sinusoid (204) in FIG. 3C. For a single sinusoid (204), the sun's rays will be perpendicular to the surface at some time of the day if the angle between the sun and the horizon is between 45° (162) and 90° (161).

[0065] FIG. 3D schematically illustrates a portion of the surface (100) of FIG. 3B, which comprises three sine waves of different wavelengths. The dashed line (204) indicates the longest-wavelength sine wave, while the solid line (106) shows the surface. Perpendiculars (1061) are shown at several points on the surface (106). It can be seen that the range of angles formed by the perpendicular to the surface is greater for a surface with secondary and tertiary corrugations (106) than for the single sinusoid (204) of FIG. 3C. Table I shows the minimum angle formed by a perpendicular to a surface comprising either primary and secondary sinusoidal corrugations (third column), or primary, secondary and tertiary sinusoidal corrugations (fourth column). The maximum angle, in all cases, is 90°. In Table I, the frequency ratios vary while the magnitude ratios (M.sub.1:M.sub.2 and M.sub.1:M.sub.3) are kept constant.

TABLE-US-00001 TABLE I Minimum Minimum Angle, Angle, Surface Surface is Sum of is Sum of Sinusoids Sinusoids with with Ratio of Ratio of Frequencies Frequencies Wavelengths Wavelengths f.sub.1 and f.sub.2 f.sub.1, f.sub.2 and f.sub.3 λ.sub.1:λ.sub.2 λ.sub.1:λ.sub.3 (°) (°)  5:1  25:1 26.5 12.5   6:1  30:1 24.8 11.0   6:1  36:1 24.8 9.9 10:1  50:1 18.5 5.4 10:1  80:1 18.5 11.6  10:1 100:1 18.5 4.4 10:1 160:1 18.5 3.1 11:1 101:1 17.6 4.4 11:1 110:1 17.6 4.1 12:1 110:1 16.4 4.0

[0066] From Table I, it can be seen that the third sinusoid significantly increases the range of angles over which the sun will be perpendicular to the surface, thereby increasing the portion of the day during which the sun is efficiently absorbed and decreasing the amount by which the surface needs to be rotated to follow the sun.

[0067] Tuning can also be done by varying the relative magnitudes of the secondary and tertiary corrugations relative to the primary corrugations. Table II shows some exemplary minimum angles for different relative magnitudes. All have the same relative wavelengths, λ.sub.1:λ.sub.2 is 6:1 and λ.sub.1:λ.sub.3 is 30:1. In all cases, the maximum angle is 90°.

TABLE-US-00002 TABLE II Minimum Minimum Angle, Angle, Surface Surface is Sum of is Sum of Sinusoids Sinusoids with with Ratio of Ratio of Magnitudes Magnitudes Magnitudes Magnitudes M.sub.1 and M.sub.2 M.sub.1, M.sub.2 and M.sub.3 M.sub.1:M.sub.2 M.sub.1:M.sub.3 (°) (°) 1:2  1:20 14.2 10.4  1:5  1:10 24.8 11   1:5  1:20 24.8 15.3  1:10 1:10 32.5 12.4  1:10 1:20 32.5 18.1  1:30 1:60 40.5 31.0 

[0068] In addition, in at least some part of the surface, the tertiary corrugations are close-packed, allowing multiple reflections and further increasing possible absorption of sunlight. Some exemplary areas where multiple reflections are likely to occur for at least some sun angles are schematically illustrated in grey in FIG. 3D. Other such areas, although not greyed, are clearly present. The amount of absorption by multiple reflection can be adjusted by adjusting the relative magnitudes of the secondary and tertiary corrugations relative to the primary corrugation and to each other. A smaller magnitude of the tertiary corrugations or a longer wavelength for the tertiary corrugations relative to the secondary corrugations will decrease the amount of absorption due to multiple reflection by decreasing the area where multiple reflections can occur.

[0069] For a structure such as that illustrated in FIG. 3D, in which the left-facing sides and the right-facing sides defined by the primary corrugation are mirror images of each other, the fraction of sunlight absorbed at a given amount of time before local noon will be the same as the fraction of sunlight absorbed at the same amount of time after local noon.

[0070] Aforesaid primary, secondary, tertiary arrangements are merely an example for macro structures, e.g., scaled from 0.01 cm to 1 cm, from 1 cm to 100 cm, from 100 cm to 1500 cm; and/or micro-structures, e.g., scaled from 0.01 μm to 1 μm, from 1 μm to 100 μm, from 100 to 1,500 μm; or nano-structures, e.g., scaled from 1 nm to 100 nm, from 100 nm to 500 nm, from 500 nm to 1,000 nm. Aforesaid primary, secondary, tertiary arrangements are at least partially provided in a liquid phase, solid phase or any mixture thereof, flexible, semi-flexible or inflexible or rigid mode.

[0071] In preferred embodiments, the frequency of the secondary corrugations is at least five times the frequency of the primary corrugations, and the frequency of the tertiary corrugations is at least five times the frequency of the secondary corrugations, so that the frequency of the tertiary corrugations is at least 25 times the frequency of the primary corrugations. In other words, the wavelength of the secondary corrugations is no more than ⅕ the wavelength of the primary corrugations, and the wavelength of the tertiary corrugations is no more than ⅕ the wavelength of the secondary corrugations.

[0072] The secondary corrugations can be of the same material as the primary corrugations, with a varying refractive index across the surface generated by the varying thickness of the material caused by the primary and secondary corrugations, the secondary corrugations can be of a different material than the primary corrugations, with the two materials having a different refractive index and any combination thereof.

[0073] The tertiary corrugations can be of the same material as the secondary corrugations, with a varying refractive index across the surface generated by the varying thickness of the material caused by the secondary and tertiary corrugations, the tertiary corrugations can be of a different material than the secondary corrugations, with the two materials having a different refractive index and any combination thereof.

[0074] Reference is now made to FIG. 4, schematically and in an out-of-scale manner illustrates in a non-limiting manner several embodiments of the macro, micro or nano structures wherein their top view is substantially rounded 107, provided in top or bottom wave line (104) and/or anywhere in-between those lines, rounded top and ellipsoidal base 108, rounded base and top 109, ellipsoidal arrangement (110) having a main longitudinal axis being parallel to wave base 1015 and/or top 104b lines; and ellipsoidal arrangement (110) having a main longitudinal axis being parallel to wave base 1015 line and/or top 1014 line, tertiary ellipsoidal arrangement and secondary arrangement (111,112, respectively) having a main longitudinal axis being tilted or perpendicular to either or both wave base 1015 and/or top 1014.

[0075] Reference is now made to FIG. 5, schematically and in an out-of-scale manner illustrates in a non-limiting manner several embodiments of the macro-, micro- or nano-structures, on either planar (1) or texturized (waved etc.) plane, wherein cross section of a concave shaped structure is at least partially, homogenously or heterogeneously having a very thin wall (nano-scale 114), wider wall (micro-scale, 115) or is filled member (116). The primary (118a), secondary (118b), tertiary arrangements structures can be rectangular, circular or otherwise shaped. Hence, as shown in a 3D perspective manner, substantially tubular structures (119), substantially cubic structures (120), substantially pyramidal structures (121) shapes or any mixture and combination thereof (e.g., concave 123a, c and convex 123b integrated or non-integrated multiple or singular structures, respectively, are provided useful.

[0076] The present device provides a corrugated surface where the corrugations are controllable, tunable and regular. The corrugations, including the tertiary corrugations, are preferably significantly longer than they are wide, unlike etched structures which are dependent on the crystallinity of the substrate so that etched structures on a crystalline material are typically approximately equi-axed. Furthermore, etching of an amorphous material reduces the thickness of the amorphous layer approximately evenly; no semi-regular peaks which are usable for refracting sunlight are produced.

[0077] Corrugations that are at least partially curved in cross-section and are preferably significantly longer than they are wide will more efficiently capture sunlight than approximately equi-axed structures that have flat sides. For example, for pyramidal structures, if the structure is aligned so that east-facing sides of the pyramids face the morning sun and the west-facing sides of the pyramids face the afternoon sun, then, when the sunlight is perpendicular to the sun-facing surfaces for an angle in a horizontal plane, approximately half of the sunlight will miss the surfaces entirely, by passing between the adjacent pyramids. If the sunlight strikes the sunward-facing surfaces at a horizontally-oblique angle, some of the sunlight will strike the south-facing surfaces, but such sunlight will strike the south-facing surfaces at a glancing angle and thus will not be efficiently absorbed, since, if the sunlight strikes east-facing sides of pyramids at an oblique, horizontal, angle of θ.sub.h, then it will strike south (or north) facing sides at an angle of (90−θ.sub.h); for θ.sub.h close to 90° for efficiency in capture for east (or west) facing slopes, (90−θ.sub.h) will be close to 0 and capture will be inefficient.

[0078] In the device of the present invention, with corrugations significantly longer than they are wide, the gaps between capturing sections are relatively small to non-existent, so that most to all of the east-facing (or west-facing) slopes will capture sunlight, whatever the horizontal angle of the sunlight and the horizontally oblique angle at which the sunlight strikes the corrugations will be the same for most if not all of the corrugations.

[0079] In addition, the longer-wavelength corrugations are more efficient at trapping long wavelength light, whereas the shorter-wavelength corrugations are more efficient at trapping the short-wavelength light, thereby making absorption of light more efficient across the wavelength spectrum and ensuring more even absorption across a day, where the early morning, late evening light comprises more long-wavelength than the midday sun, which loses less short-wavelength light to atmospheric and dust absorption.

[0080] FIGS. 6 and 7 discloses a half-bubble-like microsphere (124) and light projecting/intensifying glass-like lens-like macro-structure (125) according to yet other embodiments of the invention.

[0081] FIGS. 8 and 9 discloses a solar/photovoltaic cell with panel (126) and greenhouse with panel (127) according to yet other embodiments of the invention.