CA2690311A1 - Solar panel with light focusing optics and waveguide - Google Patents
Solar panel with light focusing optics and waveguide Download PDFInfo
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- CA2690311A1 CA2690311A1 CA 2690311 CA2690311A CA2690311A1 CA 2690311 A1 CA2690311 A1 CA 2690311A1 CA 2690311 CA2690311 CA 2690311 CA 2690311 A CA2690311 A CA 2690311A CA 2690311 A1 CA2690311 A1 CA 2690311A1
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/04—Prisms
- G02B5/045—Prism arrays
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
- F24S23/12—Light guides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
- H01L31/0547—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
- F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
- F24S2023/87—Reflectors layout
- F24S2023/872—Assemblies of spaced reflective elements on common support, e.g. Fresnel reflectors
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/52—PV systems with concentrators
Abstract
An apparatus is provided for the concentration of solar energy in a panel from a large receiving surface to a small emitting region. An optical element array directs incident sunlight by total internal reflection through a series of apertures where the light is laterally propagated between two mirrored surfaces to a region for harvesting by a solar energy collector such as a photo-voltaic cell or heat absorbent material. The optical element array and mirrored surfaces can be made extremely thin. The invention can advantageously reduce the size, weight and cost of the panel. Further the lateral propagation of concentrated light in an air medium reduces light absorption by the apparatus material resulting in less heat buildup.
Description
Solar Panel with Light Focusing Optics and Waveguide Field of the Invention This invention relates to the field of solar panels and more specifically to concentrating solar panels.
Background of the Invention Solar panels are generally large flat surface areas of solar absorbing material that convert the solar energy into usable heat or electricity or both. In thermal applications it is desirable to concentrate the sunlight to provide more efficient heat transfer as a result of higher achievable temperatures. In photovoltaic applications it is desirable to concentrate the light energy to use less semiconductor material for similar or enhanced levels of output power.
Generally concentrating solar apparatus including the present invention use solar tracking to enhance their efficiency further. Solar tracking can be either single axis or preferably dual axis. A solar panel that is lighter, thinner and more durable would have significant advantages in that less expensive and lighter duty solar tracking mechanisms could be deployed.
One general problem common to concentrating solar power collectors is that there can be a significant buildup of heat in the optical section of the panel.
Photovoltaic semiconductor material becomes less efficient at higher operating temperatures and may even suffer permanent damage if the operating temperatures are too high for sustained periods. Lenses fabricated from acrylic like materials may suffer distortions and other degradation from excessive heat.
Therefore it would be advantageous to have a concentrating solar panel design that did not accumulate heat.
Concentrating panels are presently available that use a variety of mirrors and lenses to focus the light from an input region of large cross sectional area into an output region of significantly smaller cross sectional area. Typically solar concentrating systems try to achieve concentrations of 500 to 1000 suns. To achieve these higher concentrations of solar energy typically involves constructing complex apparatus to accommodate the longer focal lengths of lens and mirror assemblies capable of receiving light over a large cross sectional area and outputting light over a small cross sectional area. Higher levels of solar concentration require even larger surface areas be integrated resulting in even thicker panels to accommodate focal lengths. Increases in the size and weight of the panel will correspondingly increase the size, strength and power requirements of the two axis tracking system. Further, more complex and larger assemblies may add to material, manufacturing, shipping and assembly costs.
Further larger assemblies introduce significant cross sectional area that may generate large forces when exposed to wind in the final installed environment.
There are examples in the previous art of solid lens concentrating systems that have been developed and optimized to be thinner and lighter. For example the lens and waveguide system taught by Morgan (WO 2008/131561) is made of acrylic. The present invention seeks to address a serious limitation of the solid lens design while retaining the objective of making a thinner and lighter panel.
Advances in semiconductors for PV (Photo Voltaic) applications have continued to be made. For example Emcor Corporation has introduced Germanium based PV technology that can convert sunlight at 40 percent efficiency at a concentration of up 500 suns generating approximately 20 watts per square centimeter, but can maintain 36 percent efficiency at a concentration of 1182 suns generating 42.9 watts per square centimeter. A solid acrylic lens system will deform under the heat of this level of solar concentration and so will require additional cooling technologies and expense in order to take advantage of these semiconductor innovations. The waveguide in the present invention uses highly polished aluminum foils that have been vacuum vapor deposited with silver with air in between reducing the thermal mass of the system significantly.
A solid acrylic lens array like that taught by Morgan would also be made in a dedicated tool. Advances in semiconductors of several technologies result in varying efficiency, size, cost tradeoffs. Germanium and Galium Arside semiconductors are extremely efficient and expense resulting in a desire for high concentration. Silicon semiconductors are less efficient but far less expensive. It would be advantageous to be able to adjust the size of the output aperture of a solar collection panel with minimal increase in material and weight and the opportunity to reuse tooling. In particular it would be advantageous to be able to use various sized pieces of semiconductor to achieve a variety of output power and cost configurations. It is apparent that at each time there will be an optimal price per watt achievable by using either less efficient material at lower concentration or highly efficient material at higher concentration. It would be advantageous if the panel design could accommodate both scenarios, or any intermediate scenario, with minimal variation in weight or cost.
Summary of the Invention A light guide solar panel comprising:
A light insertion stage made by molding lens elements into acrylic that direct and focus incident sunlight through optical apertures coupled to a waveguide. The waveguide is comprised of two flat surface reflecting mirrors such that the output aperture is air preventing heat buildup in the waveguide. The upper panel has slots cut into it which receive the focused and redirected light from the light insertion stage.]
Description of Drawings Drawing 1 A preferred embodiment of the light insertion array Drawing 2 A preferred embodiment of the upper mirror Drawing 3 A preferred embodiment of the lower mirror Drawing 4 A preferred embodiment of the solar panel assembly showing a single light ray Drawing 5 A preferred embodiment of the solar panel assembly showing multiple light rays Drawing 6 Secondary optics formed from mirror or solid elements for further light concentration and output beam shaping.
Description of Preferred Embodiments The present invention is comprised of a solar light insertion stage (2) that, through the use of an array of reflecting optical elements, (5,6) simultaneously focuses and redirects the light through a corresponding series of apertures (7) located at the focus points (4) into an optical waveguide comprised of a first mirror (8) formed with slots (7) matching each optical element. The waveguide is comprised of two surface reflecting mirrors facing each other. The upper mirror (8) has slots and has its reflecting side facing away from the light insertion stage and has slots cut into it to receive the light from the optical insertion stage. A
second mirror(9) is oriented at an angle to the first mirror with its reflecting side facing the first mirror.
The light insertion stage admits light into its receiving face and then focuses and redirects light through the slots in the the waveguide by total internal reflection.
Poly-methylmethacrylate (PMMA), having an index of refraction of 1.49 is a suitable material for forming the light input stage and the reflecting surface stage of the light insertion module. The critical angle for PMMA with air is approximately 42.5 degrees. The reflecting optical elements are constructed such that incident sunlight hits the element between the critical angle and 90 degrees.
In a preferred embodiment the light insertion stage has a flat surface that receives the sunlight and the optical elements that reflect the light are molded into in a suitable curve on the opposite side of the light insertion stage.
These optical element curves could include parabolic, elliptical, hyperbolic, flat, cubic, Cassegrain optics, Winston Cone optics, lenses, Fresnel optics, holograms, prismatic edges and a locus of points. Manufacturing methods of the light insertion stage and its optical elements will further affect the quality of the focusing and redirecting of the light resulting in either smaller or larger apertures into the waveguide section of the light panel.
Drawing #4 shows the path that a single light ray takes through the solar collection panel. In one preferred embodiment the optical element array is organized along parallel lines, all focusing and redirecting light in the same direction, such redirection further enhanced by the waveguide planar mirror being slanted in the same direction such that the solar light is exclusively concentrated on one side of the panel.Light passes from air (1) into the light insertion stage (2) that is made of a transparent material with an optical index of refraction greater than air. The light hits a parabolically shaped edge of the light insertion stage (6), where, because it is less than the critical angle, it is totally internally reflected towards the focus (4). The light exits the optical element array at edge (5).
Edge (5) edge five is formed as a lens in a concentric circle centered at the focus of the parabolic edge (6). Therefore the light hits edge (5) orthogonally and does not change its direction.
In a second embodiment the lens array is organized concentric circles, all focusing and redirecting light towards the center of the panel, such redirection further enhanced by the waveguide planar mirror being formed as a cone such that the solar light is exclusively concentrated to the center of the panel.
The waveguide is principally formed by two mirrors with their reflective sides facing each other.
In the parallel embodiment of the invention the first mirror (8) is located substantially parallel to the light insertion stage and has a series of parallel slots (7) cut into it corresponding in a one to one fashion with the optical elements of the light insertion stage. In practice in order to minimize light leakage back into the light insertion stage the mirror elements can actually be oriented at a slight angle (10), generally between 1 and five degrees. It is preferred that the mirrors reflect off of their surfaces. Highly polished thin sheets of aluminum that have been vacuum vapor deposited with silver like those manufactured by the Alanod Company are suitable for forming the first and second mirror surfaces. The reflection importantly occurs at the surface to minimize refractions and to maximizing control over the light paths. The second flat planar mirror (9) is oriented facing the first mirror at an angle to the first mirror (12) such that edge of the second mirror enhances the redirection of the light received through the slots in the first mirror to the edge of the light panel. Once the sunlight has been directed through the aperture slots into the waveguide the light rays are continually directed to the edge of the solar panel where they exit through the output aperture (13) and are available to be harvested by solar photovoltaic or solar thermal devices. Importantly the angle and length of the second planar mirror can be varied (14) in order to adjust the size of the output aperture, and as a result to vary the amount of sunlight concentration. Thus very thin, high concentration assemblies or thicker, low concentration assemblies can be made with minimal changes in the construction, weight or amount of material used.
Further because the waveguide has air between the mirrors there is minimal heat buildup in the waveguide when configured for high solar concentrations in the 500 to 1000 sun range. If necessary the system can be inexpensively cooled with either passive or active means.
In the concentric circular embodiment of the invention the first mirror is located substantially parallel to the light insertion stage and has a series of slots cut into it corresponding in a one to one fashion with the concentric circular optical elements of the light insertion stage. The second mirror, which has been formed in a conical shape is oriented facing the first mirror such that the slope of the second mirror enhances the redirection of the light received through the slots in the first mirror towards the center of the light panel.
The orientation of the two mirrors that comprise the waveguide stage of the solar panel is such that minimal light can escape from the waveguide back into the insertion stage. The light is directed to the output region through a series of reflections. The size of the output aperture can be varied significantly by varying the angle of the second mirror relative to the input stage.
Background of the Invention Solar panels are generally large flat surface areas of solar absorbing material that convert the solar energy into usable heat or electricity or both. In thermal applications it is desirable to concentrate the sunlight to provide more efficient heat transfer as a result of higher achievable temperatures. In photovoltaic applications it is desirable to concentrate the light energy to use less semiconductor material for similar or enhanced levels of output power.
Generally concentrating solar apparatus including the present invention use solar tracking to enhance their efficiency further. Solar tracking can be either single axis or preferably dual axis. A solar panel that is lighter, thinner and more durable would have significant advantages in that less expensive and lighter duty solar tracking mechanisms could be deployed.
One general problem common to concentrating solar power collectors is that there can be a significant buildup of heat in the optical section of the panel.
Photovoltaic semiconductor material becomes less efficient at higher operating temperatures and may even suffer permanent damage if the operating temperatures are too high for sustained periods. Lenses fabricated from acrylic like materials may suffer distortions and other degradation from excessive heat.
Therefore it would be advantageous to have a concentrating solar panel design that did not accumulate heat.
Concentrating panels are presently available that use a variety of mirrors and lenses to focus the light from an input region of large cross sectional area into an output region of significantly smaller cross sectional area. Typically solar concentrating systems try to achieve concentrations of 500 to 1000 suns. To achieve these higher concentrations of solar energy typically involves constructing complex apparatus to accommodate the longer focal lengths of lens and mirror assemblies capable of receiving light over a large cross sectional area and outputting light over a small cross sectional area. Higher levels of solar concentration require even larger surface areas be integrated resulting in even thicker panels to accommodate focal lengths. Increases in the size and weight of the panel will correspondingly increase the size, strength and power requirements of the two axis tracking system. Further, more complex and larger assemblies may add to material, manufacturing, shipping and assembly costs.
Further larger assemblies introduce significant cross sectional area that may generate large forces when exposed to wind in the final installed environment.
There are examples in the previous art of solid lens concentrating systems that have been developed and optimized to be thinner and lighter. For example the lens and waveguide system taught by Morgan (WO 2008/131561) is made of acrylic. The present invention seeks to address a serious limitation of the solid lens design while retaining the objective of making a thinner and lighter panel.
Advances in semiconductors for PV (Photo Voltaic) applications have continued to be made. For example Emcor Corporation has introduced Germanium based PV technology that can convert sunlight at 40 percent efficiency at a concentration of up 500 suns generating approximately 20 watts per square centimeter, but can maintain 36 percent efficiency at a concentration of 1182 suns generating 42.9 watts per square centimeter. A solid acrylic lens system will deform under the heat of this level of solar concentration and so will require additional cooling technologies and expense in order to take advantage of these semiconductor innovations. The waveguide in the present invention uses highly polished aluminum foils that have been vacuum vapor deposited with silver with air in between reducing the thermal mass of the system significantly.
A solid acrylic lens array like that taught by Morgan would also be made in a dedicated tool. Advances in semiconductors of several technologies result in varying efficiency, size, cost tradeoffs. Germanium and Galium Arside semiconductors are extremely efficient and expense resulting in a desire for high concentration. Silicon semiconductors are less efficient but far less expensive. It would be advantageous to be able to adjust the size of the output aperture of a solar collection panel with minimal increase in material and weight and the opportunity to reuse tooling. In particular it would be advantageous to be able to use various sized pieces of semiconductor to achieve a variety of output power and cost configurations. It is apparent that at each time there will be an optimal price per watt achievable by using either less efficient material at lower concentration or highly efficient material at higher concentration. It would be advantageous if the panel design could accommodate both scenarios, or any intermediate scenario, with minimal variation in weight or cost.
Summary of the Invention A light guide solar panel comprising:
A light insertion stage made by molding lens elements into acrylic that direct and focus incident sunlight through optical apertures coupled to a waveguide. The waveguide is comprised of two flat surface reflecting mirrors such that the output aperture is air preventing heat buildup in the waveguide. The upper panel has slots cut into it which receive the focused and redirected light from the light insertion stage.]
Description of Drawings Drawing 1 A preferred embodiment of the light insertion array Drawing 2 A preferred embodiment of the upper mirror Drawing 3 A preferred embodiment of the lower mirror Drawing 4 A preferred embodiment of the solar panel assembly showing a single light ray Drawing 5 A preferred embodiment of the solar panel assembly showing multiple light rays Drawing 6 Secondary optics formed from mirror or solid elements for further light concentration and output beam shaping.
Description of Preferred Embodiments The present invention is comprised of a solar light insertion stage (2) that, through the use of an array of reflecting optical elements, (5,6) simultaneously focuses and redirects the light through a corresponding series of apertures (7) located at the focus points (4) into an optical waveguide comprised of a first mirror (8) formed with slots (7) matching each optical element. The waveguide is comprised of two surface reflecting mirrors facing each other. The upper mirror (8) has slots and has its reflecting side facing away from the light insertion stage and has slots cut into it to receive the light from the optical insertion stage. A
second mirror(9) is oriented at an angle to the first mirror with its reflecting side facing the first mirror.
The light insertion stage admits light into its receiving face and then focuses and redirects light through the slots in the the waveguide by total internal reflection.
Poly-methylmethacrylate (PMMA), having an index of refraction of 1.49 is a suitable material for forming the light input stage and the reflecting surface stage of the light insertion module. The critical angle for PMMA with air is approximately 42.5 degrees. The reflecting optical elements are constructed such that incident sunlight hits the element between the critical angle and 90 degrees.
In a preferred embodiment the light insertion stage has a flat surface that receives the sunlight and the optical elements that reflect the light are molded into in a suitable curve on the opposite side of the light insertion stage.
These optical element curves could include parabolic, elliptical, hyperbolic, flat, cubic, Cassegrain optics, Winston Cone optics, lenses, Fresnel optics, holograms, prismatic edges and a locus of points. Manufacturing methods of the light insertion stage and its optical elements will further affect the quality of the focusing and redirecting of the light resulting in either smaller or larger apertures into the waveguide section of the light panel.
Drawing #4 shows the path that a single light ray takes through the solar collection panel. In one preferred embodiment the optical element array is organized along parallel lines, all focusing and redirecting light in the same direction, such redirection further enhanced by the waveguide planar mirror being slanted in the same direction such that the solar light is exclusively concentrated on one side of the panel.Light passes from air (1) into the light insertion stage (2) that is made of a transparent material with an optical index of refraction greater than air. The light hits a parabolically shaped edge of the light insertion stage (6), where, because it is less than the critical angle, it is totally internally reflected towards the focus (4). The light exits the optical element array at edge (5).
Edge (5) edge five is formed as a lens in a concentric circle centered at the focus of the parabolic edge (6). Therefore the light hits edge (5) orthogonally and does not change its direction.
In a second embodiment the lens array is organized concentric circles, all focusing and redirecting light towards the center of the panel, such redirection further enhanced by the waveguide planar mirror being formed as a cone such that the solar light is exclusively concentrated to the center of the panel.
The waveguide is principally formed by two mirrors with their reflective sides facing each other.
In the parallel embodiment of the invention the first mirror (8) is located substantially parallel to the light insertion stage and has a series of parallel slots (7) cut into it corresponding in a one to one fashion with the optical elements of the light insertion stage. In practice in order to minimize light leakage back into the light insertion stage the mirror elements can actually be oriented at a slight angle (10), generally between 1 and five degrees. It is preferred that the mirrors reflect off of their surfaces. Highly polished thin sheets of aluminum that have been vacuum vapor deposited with silver like those manufactured by the Alanod Company are suitable for forming the first and second mirror surfaces. The reflection importantly occurs at the surface to minimize refractions and to maximizing control over the light paths. The second flat planar mirror (9) is oriented facing the first mirror at an angle to the first mirror (12) such that edge of the second mirror enhances the redirection of the light received through the slots in the first mirror to the edge of the light panel. Once the sunlight has been directed through the aperture slots into the waveguide the light rays are continually directed to the edge of the solar panel where they exit through the output aperture (13) and are available to be harvested by solar photovoltaic or solar thermal devices. Importantly the angle and length of the second planar mirror can be varied (14) in order to adjust the size of the output aperture, and as a result to vary the amount of sunlight concentration. Thus very thin, high concentration assemblies or thicker, low concentration assemblies can be made with minimal changes in the construction, weight or amount of material used.
Further because the waveguide has air between the mirrors there is minimal heat buildup in the waveguide when configured for high solar concentrations in the 500 to 1000 sun range. If necessary the system can be inexpensively cooled with either passive or active means.
In the concentric circular embodiment of the invention the first mirror is located substantially parallel to the light insertion stage and has a series of slots cut into it corresponding in a one to one fashion with the concentric circular optical elements of the light insertion stage. The second mirror, which has been formed in a conical shape is oriented facing the first mirror such that the slope of the second mirror enhances the redirection of the light received through the slots in the first mirror towards the center of the light panel.
The orientation of the two mirrors that comprise the waveguide stage of the solar panel is such that minimal light can escape from the waveguide back into the insertion stage. The light is directed to the output region through a series of reflections. The size of the output aperture can be varied significantly by varying the angle of the second mirror relative to the input stage.
This allows the optimization of the solar panel design to a wide variety of PV
materials and thermal absorbing materials.
Immediately prior to solar harvesting the light can be further concentrated by introducing additional optical elements (drawing six) into the ends of the two mirrors forming the waveguide. These final stage elements can significantly increase the intensity of the output light while simultaneously redirecting or the light onto the PV solar collection region or optimizing the shape of the light panel output aperture to optimally illuminate the PV die. For example a square piece of semiconductor would be matched to a square output area.
These final stage output concentrators could include forming a full Winston cone (offset parabola), half Winston cone or simple bend into the final mirror stage.
Because the mirror is formed from thin aluminum sheets it can be formed, bent and is up to 9 percent ductile. An advantage of the present system is that the accumulation of heat at the solar collector does not propagate back into the solar panel. This eliminates the need for special cooling or interface elements.
The optical element array can be fabricated from a slab of transparent material with an index of refraction greater than air. In a preferred embodiment the array of optical elements of the light insertion stage are formed into the slab of transparent material.
At least one element of the array is comprised of a parabolic reflector that redirects the light towards a focus located at the center of the corresponding slot cut in the upper mirror of the waveguide. As the light exits the light insertion stage it passes through a second concentric optical element oriented with the focus of the parabola as its center such that the light rays hitting the exit edge of the optical element are orthogonal to the edge and remain substantially unchanged in their direction. Manufacturing tolerances and techniques will result in the accuracy of the lenses relative to the orientation of the slots in the mirror and may result in a higher or lower level of concentration.
materials and thermal absorbing materials.
Immediately prior to solar harvesting the light can be further concentrated by introducing additional optical elements (drawing six) into the ends of the two mirrors forming the waveguide. These final stage elements can significantly increase the intensity of the output light while simultaneously redirecting or the light onto the PV solar collection region or optimizing the shape of the light panel output aperture to optimally illuminate the PV die. For example a square piece of semiconductor would be matched to a square output area.
These final stage output concentrators could include forming a full Winston cone (offset parabola), half Winston cone or simple bend into the final mirror stage.
Because the mirror is formed from thin aluminum sheets it can be formed, bent and is up to 9 percent ductile. An advantage of the present system is that the accumulation of heat at the solar collector does not propagate back into the solar panel. This eliminates the need for special cooling or interface elements.
The optical element array can be fabricated from a slab of transparent material with an index of refraction greater than air. In a preferred embodiment the array of optical elements of the light insertion stage are formed into the slab of transparent material.
At least one element of the array is comprised of a parabolic reflector that redirects the light towards a focus located at the center of the corresponding slot cut in the upper mirror of the waveguide. As the light exits the light insertion stage it passes through a second concentric optical element oriented with the focus of the parabola as its center such that the light rays hitting the exit edge of the optical element are orthogonal to the edge and remain substantially unchanged in their direction. Manufacturing tolerances and techniques will result in the accuracy of the lenses relative to the orientation of the slots in the mirror and may result in a higher or lower level of concentration.
The waveguide is formed from highly reflective material with the preferred embodiment being surface reflected such that the light waves reflect of the inside edges of the waveguide. Conventional rear side reflecting mirrors could also be used but could result in further refractions and internal reflections that may diminish the efficacy of the solar panel through either light leakage or energy absorption.
In one embodiment secondary optics can be oriented at the output aperture of the waveguide to further concentrate the light onto PV (Photo Voltaic) devices. In another embodiment light absorbing devices can be oriented to take advantage of the concentrated light energy.
In another embodiment the reflector surface of the light insertion stage can be constructed by a locus of points that are non-parabolic allowing a higher concentration of incident sunlight by the solar concentrating panel. The advantage of non-parabolic shape of the elements is that certain curves, like curves represented by cubic or higher order equations can concentrate light into a region rather than a single point. This is an excellent feature of the invention because practically the slot in the mirror has to be made a finite by metal stamping, laser cutting, waterjet cutting, parallel alignment of individual pieces or similar methods width whereas the focus of a parabola is a point.
If this region is sized to be the same area as the slot cut into the mirror then one skilled in the art would realize that a totally internally reflective lens shaped like such a curve would intersect a higher percentage of the light received on the flat surface of the panel and direct that light through the aperture of finite width into the waveguide. In practice the redirecting lens contemplated by this invention re-directing lens may have advantages over the parabolic lens in that it can be can be made thinner and lighter while at the same time achieving higher concentration than the simple parabolic lens. In order to further optimize the light redirecting qualities a similarly shaped lens can be constructed on the exit face of the light insertion stage such that further optimization of the light beam shape can be made utilizing the fact that transmission from a slower optical medium to a faster optical medium causes redirection of the light rays.
At the present time it is the intention that the shape of the reflective surfaces by formed by injection molding or a form of machining that allows the part to be manufactured using line of draw tooling. Changes or improvements in the manufacturing method, or breaking the parts into multiple pieces that are assembled by different methods than those presently contemplated may be able to further reduce the weight and cost of the solar concentrating panel.
In one embodiment secondary optics can be oriented at the output aperture of the waveguide to further concentrate the light onto PV (Photo Voltaic) devices. In another embodiment light absorbing devices can be oriented to take advantage of the concentrated light energy.
In another embodiment the reflector surface of the light insertion stage can be constructed by a locus of points that are non-parabolic allowing a higher concentration of incident sunlight by the solar concentrating panel. The advantage of non-parabolic shape of the elements is that certain curves, like curves represented by cubic or higher order equations can concentrate light into a region rather than a single point. This is an excellent feature of the invention because practically the slot in the mirror has to be made a finite by metal stamping, laser cutting, waterjet cutting, parallel alignment of individual pieces or similar methods width whereas the focus of a parabola is a point.
If this region is sized to be the same area as the slot cut into the mirror then one skilled in the art would realize that a totally internally reflective lens shaped like such a curve would intersect a higher percentage of the light received on the flat surface of the panel and direct that light through the aperture of finite width into the waveguide. In practice the redirecting lens contemplated by this invention re-directing lens may have advantages over the parabolic lens in that it can be can be made thinner and lighter while at the same time achieving higher concentration than the simple parabolic lens. In order to further optimize the light redirecting qualities a similarly shaped lens can be constructed on the exit face of the light insertion stage such that further optimization of the light beam shape can be made utilizing the fact that transmission from a slower optical medium to a faster optical medium causes redirection of the light rays.
At the present time it is the intention that the shape of the reflective surfaces by formed by injection molding or a form of machining that allows the part to be manufactured using line of draw tooling. Changes or improvements in the manufacturing method, or breaking the parts into multiple pieces that are assembled by different methods than those presently contemplated may be able to further reduce the weight and cost of the solar concentrating panel.
Claims (4)
1. A light guide solar panel comprising A light insertion stage made by molding lens elements into acrylic that direct and focus incident sunlight through optical apertures coupled to a waveguide. The waveguide is comprised of two flat surface reflecting mirrors such that the output aperture is air preventing heat buildup in the waveguide. The upper panel has slots cut into it which receive the focused and redirected light from the light insertion stage.
2. The light guide solar panel of claim 1 wherein the light insertion stage optical elements are oriented in parallel with, and matching to the wave guide upper mirror slots.
3. The light guide solar panel of claim 1 or 2 wherein the elements are arranged in parallel lines.
4. The light guide solar panel of any one of claims 1, 2 and 3 wherein the elements are arranged in concentric circles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2690311 CA2690311A1 (en) | 2010-01-15 | 2010-01-15 | Solar panel with light focusing optics and waveguide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2690311 CA2690311A1 (en) | 2010-01-15 | 2010-01-15 | Solar panel with light focusing optics and waveguide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2690311A1 true CA2690311A1 (en) | 2011-07-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2690311 Abandoned CA2690311A1 (en) | 2010-01-15 | 2010-01-15 | Solar panel with light focusing optics and waveguide |
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| Country | Link |
|---|---|
| CA (1) | CA2690311A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111989532A (en) * | 2018-04-16 | 2020-11-24 | 罗米·M·费恩 | Manufacturing method, structure and application of passive radiation cooling |
-
2010
- 2010-01-15 CA CA 2690311 patent/CA2690311A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111989532A (en) * | 2018-04-16 | 2020-11-24 | 罗米·M·费恩 | Manufacturing method, structure and application of passive radiation cooling |
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