US20070199563A1

US20070199563A1 - Apparatus for concentration and conversion of solar energy

Info

Publication number: US20070199563A1
Application number: US11/707,461
Authority: US
Inventors: Martin Fox
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-02-16
Filing date: 2007-02-16
Publication date: 2007-08-30

Abstract

The present invention is directed to an apparatus for the collection and conversion of light energy including a collector element defining the shape of a pentagon, and a concentrator including a plurality of pentagon shaped reflector elements symmetrically arranged around the collector element. Each of the reflector elements being disposed at an angle relative to a plane of the collector element and having an edge thereof substantially aligned with and adjacent one of the sides of the collector element.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 60/774,237 filed on Feb. 16, 2006 and titled “Apparatus for Concentration and Conversion of Solar Energy”. The disclosure of the provisional application is incorporated in its entirety herein by reference.

FIELD OF THE INVENTION

The present invention pertains generally to apparatus for the collection and conversion of solar energy to other types of useful energy. More particularly the invention is directed to an apparatus for the collection and conversion of light energy having a plurality of pentagonal reflector elements arranged about a pentagonal shaped collector element.

BACKGROUND OF THE INVENTION

Solar concentrators collect sunlight over an area and direct the light onto a collection or conversion element such as a photovoltaic element. Typically, the collection or conversion element defines a smaller surface area than that of the concentrator. In this way, the radiant energy incident on the entire area of the concentrator is directed to the collection or conversion element and converted to useful energy such as electrical power where the concentrator is coupled to a photovoltaic element.
Current solar collectors and conversions systems include a wide range of devices including the use of lenses and reflectors which are often very sensitive to the angle of incidence of the sunlight. Other devices employ tracking systems to track the sun's movement and thereby attempt to optimize the position of a solar collector relative to the angle of the sunlight.
Representative examples of prior art devices for the collection and conversion of solar energy include:
U.S. Pat. No. 6,700,055 to Barone discloses a solar concentrator system including a collector lens for collecting and at least partially focusing incident solar rays, a solar cell and a lens array positioned generally between the collector lens and the solar cell, the lens array directing the partially focused rays emerging from the collector lens onto the solar cell.
U.S. Pat. No. 6,700,054 to Cherney et al. which discloses a solar collection system and method having means for receiving solar radiation through a main refractive interface and means for internally reflecting at least once a portion of the solar radiation. The refractive medium may be liquid, gel or solid. The device can be integrated with a photovoltaic device, a photohydrolytic device, a heat engine, a light pipe or a photothermal receptor.
U.S. Pat. No. 6,840,645 discloses a light tube system for distributing sunlight or artificial light. One embodiment of the system includes a pair of opposed reflectors rotatably mounted to track the movement of the sun.
U.S. Pat. No. 6,061,181 is directed to a nontracking light converger including a housing surrounding a light absorbing means such as a heat conductive conduit or a photovoltaic cell collector plate. Angularly extending from the upper surface of the light absorbing means are a plurality of substantially triangular prisms for refracting and directing light from the open top of the housing downwardly towards the light absorbing means.
One disadvantage of many prior art devices is that they require one of more lenses for focusing the sunlight onto a solar cell or other device which can be an expensive components and significantly add to the cost of the energy generated.
Another disadvantage of many prior art systems is the requirement of a tracking system which also significantly adds to the cost of the energy.
Based on the foregoing, it is the general object of the present invention to provide an apparatus for the concentration and conversion of solar energy that overcomes many of the problems and drawbacks of prior art systems.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for the collection and conversion of light energy including a collector element defining the shape of a pentagon, and a concentrator including a plurality of pentagon shaped reflector elements symmetrically arranged around the collector element. Each of the reflector elements disposed at an angle relative to a plane of the collector element and having an edge thereof substantially aligned with and adjacent one of the sides of the collector element.
In one embodiment, the concentrator includes five reflector elements each defining the shape of a regular pentagon, a regular pentagon having five sides of equal length. The apparatus of the present invention including reflector elements shaped as regular pentagons provides an increased concentration of 2.5 times the suns radiation on the collector element or “2.5 suns”.
In other embodiments of the present invention irregular pentagons are utilized to provide further enhanced concentration of light incident on the collector element.
One object of the present invention is to provide an apparatus for solar concentration on a collector element ranging from about 3 times to about 6 times the incident radiation of the sun.
Another object of the present invention is to provide a cost effective solar collection and conversion device including only readily available reflective materials, such as flat mirrors configured according to novel geometries so as to produce enhanced solar concentration.
Another object of the present invention is to provide an apparatus for solar collection and conversion which is small and lightweight and useful for various applications such as recharging batteries for electronic devices such as cellular telephones, computers, personal digital assistants (PDAs), and other similar devices.
Another object of the present invention is to provide large-scale apparatus for solar collection and conversion for mounting on buildings, vehicles, or in remote locations having limited access to electrical power.
Another object of the present invention is to provide an apparatus for solar collection and conversion wherein the energy produced by the apparatus allows for recouping the cost of the apparatus within a range of about two to about four years.
A further object of the present invention is to provide an apparatus for solar collection and conversion that includes embodiments that are affordable and cost-effective for industrial, municipal, residential and personal applications.
These and other objects, features and advantages of the present invention will become more apparent in view of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of an apparatus for the collection and conversion of light energy according to the present invention.
FIG. 2 is an illustration showing an example of the reflection of solar rays incident on the reflective elements of the present invention.
FIG. 3 is an illustration comparing the geometry of two different pentagons useful in various embodiments of the concentrator of the present invention.
FIG. 4 is an illustration showing the geometry of the irregular shaped pentagon of FIG. 2 in accordance with one embodiment of the concentrator of the present invention wherein the reflectors abut an adjacent reflector throughout substantially the entire length of the adjoining sides therebetween.
FIG. 5 is an illustration showing the geometry of another pentagon used in accordance with another embodiment of the concentrator of the present invention.
FIG. 6 is a perspective view of one embodiment of a light pipe in accordance with the present invention.
FIG. 7 is a perspective view of one embodiment of a thermal oven in accordance with the present invention.
FIG. 8 is a perspective view of one embodiment of a photovoltaic electrical power generator in accordance with the present invention.
FIG. 9 is a perspective view of a solar water heater according to the present invention.
FIG. 10 is an illustration of a solar tracking photovoltaic electrical power generator according to the present invention.
FIG. 11 shows a plurality of the apparatus of the present invention shown mounted on a flat surface collectively forming a collector array.
FIGS. 12A and 12B are perspective views of one embodiment of the apparatus of the present invention which is collapsible.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, one embodiment of an apparatus for the collection and conversion of light energy in accordance with the present invention is generally referred to by the reference number 10. The apparatus 10 includes a collector or conversion element hereinafter referred to generally as a “collector element” and identified by the reference numeral 12. A concentrator 13 includes a plurality of reflector elements 14 arranged about the perimeter of the collector element 12 and disposed at an angle Θ relative to a plane P defined by the collector element 12 and the X and Y axes shown in FIG. 1.
In a preferred embodiment of the present invention, as shown in FIG. 1, the collector element 12 includes a collector surface 15 which defines a regular pentagon, i.e. a pentagon having five sides of equal length. The collector element 12 includes a plurality of photovoltaic solar cells 16 arranged throughout the collector surface 15 for converting the radiant energy incident on the solar cells to electrical power. Typically, the solar cells 16 utilize crystalline silicon or gallium-arsenide or other materials which are known in the art.
A plurality of reflector elements 14 are arranged symmetrically around the perimeter of the collector element 12. In the FIG. 1 embodiment, the reflector elements 14 each define a regular pentagon 17 wherein a lower edge 18 of each of the regular pentagons is arranged to abut an edge 20 of the collector surface which is adjacent thereto. In the FIG. 1 embodiment, the reflector elements 14 are each disposed at angle Θ equal to sixty degrees from the collector surface 15 resulting in each of the regular pentagons 17 having a side edge 22 being spaced apart from the side edge 22 of an adjacent regular pentagon at an angle of approximately 4 degrees (the spacing being identified by the reference number 24 in FIG. 1).
FIG. 2 illustrates the reflection R of a light ray I incident on one of the reflector elements 14 of the apparatus 10. The incoming light ray I is reflected from the reflector element 14 and is incident on the collector surface 15 at an opposite edge thereof. Although not shown, intermediate light rays incident on the reflector element 14 are equally distributed to the collector element 12 throughout the collector surface 15.
In the FIG. 1 embodiment, there is a five to one ratio between the area of the collector surface 15 and the total working area of the five reflector elements 14 thereby increasing the effective area of the collector surface 15. The light gathering ability of the apparatus 10 is defined generally by the additional effective area of the collector element 12. In the FIG. 1 embodiment, each of the reflector elements 14 provide illumination equal to approximately 50% the light energy incident on the collector surface 15 directly. Thus, with five reflector elements 14 the available solar photonic radiation incident on the collector surface 15 is increased by a factor of 2.5. Accordingly, the increased light energy of 2.5 times that incident directly on the collector surface 15, plus the 1 times the light which is incident directly on the collector surface equals a total of 3.5 times the suns radiation on the collector surface or 3.5 “suns”. Thus, the FIG. 1 embodiment of the apparatus 10 according to the present invention including five reflector elements 14 which each define a regular pentagon 17 provides a total collection power of approximately 3.5 suns.
In other embodiments of the present invention, the apparatus 10 is constructed using reflector elements 14 which define irregular pentagons. Two examples are identified following including a discussion of the advantages of the different arrangements.
Referring to FIGS. 3 and 4, an irregular pentagon 30 is provided for the reflector elements 14 of the present invention that provides uniform illumination of the collector surface 15 and forms a “closed geometry” concentrator 13 of the apparatus 10 such that the reflector elements 14 adjacent to one another abut along substantially the entire length of the side edges 22 thereof. (See FIG. 11). This closed geometry of the irregular pentagon 30 provides for the maximum mechanical strength of the concentrator 13 wherein a plurality of the reflector elements are coupled together adjacent one another along the edges 22 thereof. Additionally, the pentagon 30 provides for efficient usage of the material of the reflector elements 14 as there should be no waste between the side edges 22 thereof when multiple reflector elements are formed from a single sheet of material. The reflector elements 14 can be attached one to the other and to the collector element 15 using various methods including adhesives, clamps, brackets or similar devices.
The above-identified characteristics of pentagon 30 are achieved by reducing the elevation angle Θ from 60 degree of the regular pentagon 17 of FIG. 1, to 58.2824 degree, increasing the base internal angles B to 110.905 degree, and a linear compression of 0.85064 (thereby reducing the height h) of the pentagon. The apparatus 10 having a plurality of reflector elements 14 corresponding to the shape of pentagon 30 provides a dosed geometry for the concentrator 13 yielding a solar concentration of 3.24 suns.
The geometry of pentagon 30 is particularly effective for a concentrator 13 formed from a unitary embossed reflective plate with single crystal photovoltaic elements in a well thereof which provides the collector element 12. Also due to the more open geometry resulting from the lower angle of elevation Θ, the pentagon 30 design provides improved efficiency than the regular pentagon for use in stationary non-tracking systems.
Referring again to FIG. 1, in another embodiment, the concentrator 13 is formed using the regular pentagons 17 in a closed geometry configuration by including a non-reflective gap-filler material to close the gaps 24 between the reflector elements 14. Typically, a non-reflective material can be used to black out the reflector portion of a mirror in the areas 24, or the regular pentagon shaped reflector is mounted to a base plate shaped as the regular pentagon 17 with a border to include the areas 24. Accordingly, the apparatus 10 includes a concentrator 13 having a closed geometry structure with the reflector elements 14 defined by regular pentagons 17.
Referring to FIG. 5, another embodiment of the apparatus 10 provides a closed geometry concentrator 13 having a plurality of reflector elements 14 each defining an irregular pentagon 40 based on a dodecahedron which defines an elevation angle Θ equal to 63.4 degree relative to the collector element 12. Thus, in a dodecahedral embodiment, the concentrator 13 includes five pentagons 40 arranged at an elevation angle Θ equal to 63.4 degree relative to the collector element 12. As shown in FIG. 5, the pentagon 40 includes base internal angles B equal to 108 degree, and a linear extension of 1.34164, thereby increasing the height h of a regular pentagon 17. The pentagon 42 represents the active reflecting portion of the reflector element 14 for maintaining uniform illumination of the collector element 12 at the elevation angle Θ equal to 63.4 degree. The concentrator 13 having a plurality of reflector elements 14 corresponding to the shape of pentagon 40 provides a closed geometry for the concentrator 13 yielding a solar concentration of 4.0 suns which is a 14% increase over the concentrator 13 formed from the regular pentagons 17.
In general, when the elevation angle Θ of the reflector elements 14 is increased, the half angles between the sun and the normal to the reflector elements are also increased and the outer reflected rays are pulled inward. Increasing the height of the pentagon allows the outer rays to be reflected so as to contact the collector element 12 at an opposing edge thereof thereby providing an increase in the light energy incident on the collector element 12 when compared with a concentrator 13 formed of regular pentagons 17.
Referring again to FIG. 5, in the dodecahedral embodiment, the concentrator 13 provides a dosed geometry structure as defined by five of the pentagons 40; however, to maintain uniform illumination on the collector element 12, the reflective element utilized is restricted to the pentagon 44. The areas 46 shown between the pentagons are blacked out or left open such that there is no reflective surface in these areas. Thus, in the dodecahedral embodiment, even though the black out areas 46 are required, the concentrator 13 provides a closed geometry structure yielding a 4 sun concentration incident on output of the collector element.
In other embodiments of the present invention, the concentrator 13 can provide still further increases in concentration levels; e.g., at an elevation angle Θ of 67 degree, the concentrator will provide a concentration of approximately 4.5 sun; at an elevation angle Θ of 71 degree, the concentrator will provide a concentration of approximately 5 sun; at further increased elevation angles, a maximum concentration level of 6 sun is achievable. However, concentrators 13 providing these higher concentrations require larger reflector elements 14 which can be impractical for some applications due in part to the cost of the reflectors utilized.
Referring to FIG. 6, in another embodiment of the present invention, the apparatus 10 includes a concentrator 13 coupled to a collector element 12 including a light pipe 46.
In the FIG. 7 embodiment, the apparatus 10 includes a concentrator 13 coupled to a collector element 12 including a thermal oven 48 or other type of photothermal receptor.
Referring to FIG. 8, another embodiment of the apparatus 10 includes a collector element 12 including a photovoltaic array 50 coupled to a solar controller 52.
Referring to FIG. 9, another embodiment of the apparatus 10 includes a collector element 12 having a tubing array 54 for carrying a liquid or gel for transferring concentrated radiant energy from the concentrator 13 thereto.
Referring to FIG. 10, the apparatus 10 in accordance with the present invention includes a tracking mechanism 56 and controller 58 therefor, for tracking the movement of the sun and focusing the collector element 12 towards the sun for further increasing the incidence of sunlight on the collector element. The tracking mechanism 56 provides a means of tracking the position of a source of incident light and adjusting the position of the apparatus 10 with respect thereto so as to optimize the collection of light energy.
Referring to FIG. 11, in another embodiment of the present invention, a plurality of the apparatus 10 are arranged adjacent one another attached to a surface 60 collectively forming a collector array 62.
Referring to FIGS. 12A and 12B, one embodiment of the apparatus 10 of the present invention includes a concentrator 13 which is collapsible wherein each of the reflective elements 14 is pivotably coupled to the collector element 12 and movable between open and dosed positions. When the reflector elements 14 are in the open position, shown in FIG. 12A, the collector element 12 is exposed and the apparatus 10 is operational. In the closed position, shown in FIG. 12B, the concentrator 13 includes each of the reflector elements 14 folded over one another such that the reflective portions thereof and the collector element 12 are protected from the weather. The reflector elements 14 may be folded up for convenience, storage, portability and/or to protect the reflector elements and the collection element from damage, moisture and environmental exposure.
In the FIGS. 12A and 12B embodiment, the concentrator 13 includes reflector elements 14 defining regular pentagons 17 such that the concentrator defines an open structure having a gap between the side edges 22 of the adjacent reflector elements as set forth above. This open geometry of the concentrator 13 facilitates the pivotable arrangement of the reflector elements 14 required for the collapsible and/or portable design of the FIG. 12 embodiment of the apparatus 10.
In other embodiments of the apparatus 10, the reflective elements are connected to the collection element 12 by a connector such as a fixed, adjustable, hinged, rotatable, and remotely controllable connector.
In various embodiments of the present invention, the reflector elements 14 are manufactured from materials including mirrors, reflective plastic materials, reflective metal materials and elements enclosing reflective particles suspended in a fluid, gel or solid medium.
The collection element 12 can include photovoltaic cells, photovoltaic panels, coiled tubing containing a heatable fluid, a light pipe, a solar oven, a water heater, a hot water-powered turbine, and devices suitable for recharging batteries as well as other types of energy conversion devices.
Accordingly, the present invention apparatus for the collection and conversion of light energy 10 provides an efficient method to collect and concentrate light and other forms of radiation including sunlight, moonlight, lightning, artificial light, reflected light, refracted light and UV radiation.
The foregoing description of embodiments of the invention have been presented for the purpose of illustration and description, it is not intended to be exhaustive or to limit the invention to the form disclosed. Obvious modifications and variations are possible in light of the above disdosure. The embodiments described were chosen to best illustrate the principals of the invention and practical applications thereof to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

Claims

1. An apparatus for the collection and conversion of light energy comprising:

a collector element defining the shape of a pentagon, and

a concentrator including a plurality of pentagon shaped reflector elements symmetrically arranged around the collector element, each of the reflector elements disposed at an angle relative to a plane of the collector element and having an edge thereof substantially aligned with and adjacent one of the sides of the collector element.

2. The apparatus of claim 1 wherein the reflective elements are positioned at about a 60 degree angle relative to the plane of the collection element.

3. The apparatus of claim 1 wherein the reflective elements are positioned relative to the collection element at angles corresponding to those in a dodecahedron Platonic solid.

4. The apparatus of claim 1 wherein each of the reflective elements are positioned relative to the collection element an angle thereto to uniformly distribute the reflected light across a surface of the collector element.

5. The apparatus of claim 1 wherein each of the shape of at least one of the reflective elements defines a regular pentagon.

6. The apparatus of claim 1 wherein the geometry of at least one of the reflective elements is that of an irregular pentagon.

7. The apparatus of claim 1 wherein the reflective elements comprise one or more regular pentagons and one or more irregular pentagons.

8. The apparatus of claim 1 wherein the reflective elements are connected to the collection element by a connection mode selected from the group comprising: fixed, adjustable, hinged, rotatable, and remotely controllable.

9. The apparatus of claim 1 further comprising a means of tracking the position of a source of incident light and adjusting the position of the apparatus with respect thereto so as to optimize the collection of light energy.

10. The apparatus of claim 1 wherein the reflective elements are selected from the group comprising mirrors, reflective plastic materials, reflective metal materials and elements enclosing reflective particles suspended in a fluid, gel or solid medium.

11. The apparatus of claim 1 wherein the collection element is selected from the group comprising photovoltaic cells, photovoltaic panels, coiled tubing containing a heatable fluid, light pipe, solar oven, water heater, hot water-powered turbine, and devices suitable for recharging batteries.

12. The apparatus of claim 1 wherein the pentagonal reflective elements abut the adjoining such elements along most or all of their respective abutting edges.

13. The apparatus of claim 1 wherein the reflective elements are positioned relative to the plane of the collection element at an angle between about 50 degrees and about 72 degrees.

14. The apparatus of claim 1 wherein the reflective elements are positioned relative to the plane of the collection element at an angle between about 58 degrees and about 62 degrees.

15. The apparatus of claim 1 wherein the reflective elements are positioned relative to the collection element at any angle that provides at least 2 suns of light concentration on the collector element.

16. An apparatus for the collection and conversion of solar energy comprising a plurality of pentagon-shaped reflective elements symmetrically arranged around a pentagon-shaped collector element.

17. The apparatus of claim 16 wherein at least one of the reflective elements defines the geometry of a regular pentagon.

18. The apparatus of claim 16 wherein at least one of the reflective elements defines the geometry of an irregular pentagon and wherein the collection element defines the geometry of a regular pentagon.

19. The apparatus of claim 1 wherein the reflective elements may be folded up for convenience, portability and to protect said elements and the collection element from damage, moisture environmental exposure.