Abstract
An apparatus for generating electricity with the ability to distill a liquid and/or expand a working fluid and/or produce mechanical energy and/or produce thermal energy and/or produce chemical transformations through separately utilizing light in the infrared (IR) region and light within the visible and ultraviolet (UV) regions. The apparatus uses methods to capture diffuse and direct polychromatic light, concentration and multiplication of that light up to 1000 times or more, collimation of light, separation of the spectrum into the IR and UV/visible bands, generation of electricity through conversion of at least UV/visible light, and useful conversion of infrared light into applications to generate a distilled liquid or compound, expand a working fluid, produce mechanical energy, produce thermal energy, produce chemical energy and/or generate additional electricity. Non-reflected radiant energy may be used to operate a suitable photovoltaic cell or stack of cells. In alternative embodiments, the spectral separator may reflect most radiant energy incident upon it to one or more photovoltaic cells and pass infrared to an accumulator for use as heat energy to generate mechanical or chemical energy or generate further electrical energy.
Claims
1. Apparatus for obtaining radiant energy from a polychromatic radiant energy source, the apparatus comprising: a flat, configurable concentrating lens for concentrating the radiant energy to a multiple of incident radiant energy, the multiple being a factor of up to approximately ten times or more; a converging domed Fresnel lens mounted on the flat, configurable concentrating lens for further concentrating the radiant energy to a combined multiplication factor being approximately one thousand times or more, the flat and domed Fresnel lens forming a converging Fresnel lens system; a spectral separator at an angle between 20° and 80° to the concentrated light for separating the concentrated radiant energy into spectral bands, the spectral separator being approximately ten times smaller in surface area than the Fresnel lens system; a photovoltaic device for receiving a first spectral band comprising visible light passed by the spectral separator and converting the received first spectral UV/visible band into electricity; and a second device for receiving a second spectral band comprising infrared electromagnetic energy reflected by the spectral separator and for utilizing at least one of converted electrical energy and infrared heat energy received in said infrared electromagnetic energy.
2. The apparatus of claim 1 wherein the ratio between the sizes of the flat lens in combination with the converging domed Fresnel lens and a detector area of either the first or the second device ranges from one thousand to twenty-five hundred times.
3. The apparatus of claim 1 wherein the concentrator comprises a collimator and a diverging Fresnel lens after the collimator.
4. The apparatus of claim 1 wherein the collimator concentrator and Fresnel lens system comprise a converging Fresnel lens for concentrating the radiant energy to a multiple of incident energy of approximately one thousand times and an energy efficiency in excess of 36% and up to 60% or more between the incident energy and useful energy output.
5. The apparatus of claim 1 wherein the collimator concentrator and Fresnel lens system comprise a shaped converging Fresnel lens having a circular footprint on a flat surface to capture diffused incident light providing up to 15% or greater light capturing capability.
6. The apparatus of claim 1 wherein the spectral separator comprises a dichroic lens and the spectral bands comprise a first spectral band comprising ultraviolet and visible light bands, and a second spectral band comprising infrared electromagnetic energy of wavelengths of 700 nm and up to 1000 nm.
7. The apparatus of claim 6 wherein the dichroic lens comprises a plurality of dichroic lenses operable at different bands in the combined visible and ultraviolet spectrum.
8. The apparatus of claim 1 further comprising a dual axis tracking motor system for moving said apparatus to follow a direct or diffuse source of solar electromagnetic radiation.
9. The apparatus of claim 4 further comprising an infrared Fresnel lens.
10. The apparatus of claim 1 wherein the second device includes a heat accumulator.
11. The apparatus of claim 1 wherein the second device includes a gallium antimonide (GaSb) photovoltaic device, responsive to the spectral separator, to convert the second spectral band comprised of infrared electromagnetic energy into electricity.
12. Apparatus for obtaining radiant energy from a polychromatic radiant energy source, the apparatus comprising: a collimator concentrator for concentrating the radiant energy to a multiple of incident radiant energy, the multiple being a factor of up to approximately ten or more; a Fresnel lens having a dome shape on a flat surface for concentrating radiant energy to a multiple of incident radiant energy to a combined multiplication factor of up to two thousand times; a spectral separator for separating the concentrated radiant energy into spectral bands, the spectral separator comprising a transmitter of one spectral band and a reflector of the second spectral band; a first photovoltaic device, responsive to the spectral separator, for receiving a first spectral band comprising visible and ultraviolet light and converting the received first spectral band into electricity; and a second photovoltaic device for receiving a second spectral band comprising infrared electromagnetic energy and for utilizing at least heat energy received in said infrared electromagnetic energy.
13. The apparatus of claim 12 further comprising a converging Fresnel lens for further concentrating the radiant energy to a factor up to two thousand times the Fresnel lens having a square shape and being a multiple of forty times the size of the first and second devices.
14. The apparatus of claim 12 further wherein the spectral separator comprises a hot dichroic lens.
15. The apparatus of claim 12 wherein the spectral separator comprises a cold dichroic lens.
16. The apparatus of claim 12 comprising an array of Fresnel lens, collimator and spectral separators focusing energy at a central accumulator.
17. A method for converting radiant solar energy to electric energy and to another form of energy comprising: a collimator concentrator for concentrating the electromagnetic, radiant energy to a multiple of incident electromagnetic radiant energy, the multiple being a factor of up to approximately ten times or more; a Fresnel lens system for concentrating the electromagnetic, radiant energy to a multiple of incident electromagnetic radiant energy, the combined multiplication factor of the collimator concentrator and the Fresnel lens system being approximately up to one thousand times or more; a spectral separator for separating the concentrated radiant energy into first and second spectral bands, the first spectral band comprising the visible light spectrum and the second spectral band comprising the infrared electromagnetic, radiant energy band; a first photovoltaic device, responsive to the spectral separator, for receiving the first spectral band and converting the received first spectral band into electricity; and a second photovoltaic device, responsive to the spectral separator, for receiving the second spectral band and for utilizing energy received in said second spectral band of said infrared electromagnetic, radiant energy for a different application than for conversion to electricity.
18. The method of claim 17 wherein the other form of energy is one of mechanical, chemical, electrical and thermal energy where electrical energy is provided by the first photovoltaic device and the second photovoltaic device with an overall light to electricity conversion efficiency in excess of fifty percent.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 provides an overall system diagram showing a first embodiment of a radiant energy concentrator system including a spectral separator.
[0044] FIG. 2 provides an enlarged diagram of light devices including the spectral separator of FIG. 1.
[0045] FIG. 3(A)-(B) provide alternative embodiments of light devices including a collimator and Fresnel lens systems for separating received radiant energy into bands for electrical, chemical and mechanical energy generation.
[0046] FIG. 4(A) shows a perspective view of an exemplary array of 2 by 2 Fresnel lens systems for delivering a first visible light band to respective photovoltaic cells and dichroic lenses for transmitting infrared light as heat to a central collector column of heat for delivery to various mechanical and chemical systems as will be further discussed herein; FIG. 4(B) shows a side view of the embodiment of FIG. 4(A) and FIG. 4(C) shows a bottom view of the embodiment of FIG. 4(A).
[0047] FIG. 5 in table and schematic form shows what may be referred to herein as the Five C's or principles of operation of a preferred embodiment of a hybrid solar concentrator, namely, Capture, Concentrate, Collimate and Constructively Convert and more to show new domed lens and components taken from what Parker has recently sent. A domed concentrator Fresnel Lens receives diffuse and point source sun light and focuses the received light, for example, on to a spectral separator for focusing on a UV/visible PV cell and an IR p/n junction cell.
[0048] FIGS. 6 through 11 provide a step-by-step process of constructing a high efficiency hybrid solar concentrator. The structure described simultaneous manages both heat and optics to achieve the most efficient conversion. Collimation is used to uniformly apply both intensity and color to reduce hot spots and structural moieties. Also, spectral reduces heat generation on from visible and infrared on both photovoltaic devices, thus reducing the heat load required to manage. Lastly, use of the Al monoblock with heat fins easily radiates any excess heat from the system which produces a high efficiency, low cost solar technology.
[0049] FIG. 6 shows in perspective view a domed Fresnel lens for capturing direct sunlight as well as diffuse light from the sun and outputting and concentrating the light like a funnel for reception at collimator 615 in a structure comprising brackets 645 for holding a collimator/separator/PV cells assembly seen in FIG. 6 only as collimator 615. As can be seen from FIG. 6, the domed Fresnel lens comprises a circular domed portion and a flat portion for focusing received light on collimator 615.
[0050] FIG. 7 shows in side view the brackets 645 and the domed Fresnel lens 620 with electrical conductors coming from the bottom of an assembly for generating electricity (not shown) comprising the collimator, spectral separator (hot or cold), a UV/visible PV cell below and reflected IR is received by a IR p/n junction cell.
[0051] FIG. 8 shows the assembly of a collimator 615, a spectral separator such as a cold mirror 840 for reflecting infrared energy to IR detector 870 seen as a first rectangular chip and a UV/visible detector or PV cell 850. The entire assembly is preferably provided with a heat sink 885 for alleviating heat build-up and protecting the chips from damage.
[0052] FIG. 9 shows a side cut-away view of the assembly of FIG. 8 with the collimator 615 cut in half exposed at the top and with spectral separator 840 reflecting infrared to PV p/n junction 870 and UV/visible to a UV/visible PV multi junction cell only visible because of a bolt for fixing the cell to the assembly. Again, the assembly is shown having a heat sink 885.
[0053] FIG. 10 exemplifies the reception at a UV/visible PV cell that is 10 mm by 10 mm such that the combination of the domed Fresnel lens, the collimator, the spectral separator (for example, a cold mirror) provides an even uniformity of irradiance within a 10 mm diameter circle at best focus. Because of the combination, multiplication magnitudes on the order of one to two thousand power are achieved and because of the dark regions, the integrated circuit assembly of the PV cell is left undisturbed by damaging heat.
[0054] FIG. 11 provides a top view of an aluminum monoblock assembly with the collimator and spectral separator removed. What is left are the heat sink 885, the UV/visible PV cell 850 and the IR p/n junction cell 870 showing electrical and heat conduction.
[0055] FIG. 12 shows an assembly of four such electricity generators with their respective dome-shaped Fresnel lens 620-1 through 620-4 at the top.
[0056] FIG. 13 shows dual axis tracking where a motor may track the sun from sunrise to sunset and a second motor may operate the North/South axis for tilting the structure of four cells to mtch the changing seasons and height of the sun in the sky.
[0057] FIG. 14 shows a graph of angle of incidence (AOI) measured against power on a detector such as a UV/visible detector for a domed Fresnel lens versus a conventional flat Fresnel lens, the graph showing a great increase in power over an AOI of zero to 0.2 degrees.
[0058] FIG. 15 shows the geometry of dimensions between lenses, cold mirrors and detectors where A is the distance from the Fresnel lens to the detector (in the case of a domed lens, the distance from the maximum sag to the detector, B is the distance from the vertex of a custom negative lens to a detector and dimension C is the midpoint of the cold mirror (spectral separator) to the detector.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0059] Similar reference characters will be used with reference to FIGS. 1-14 to represent similar elements. Referring to an example reference numeral XYY, X may represent the figure number where the component first appears and YY the two digit reference numeral for a similar earlier described component. An embodiment of a high efficiency hybrid solar concentrator may be described by way of introduction to what may be referred to as the five C's: capture, concentrate, collimate and constructively convert. First, we will discuss capture which has as an object the task of both capturing diffuse light and solar origin light. In connection with one embodiment of the present invention, the function of capture is best performed by a circular Fresnel lens 520 laid on a flat Fresnel lens surface. The high power solar concentrator may use this specially shaped Fresnel lens to obtain concentration on the order of one thousand suns or one thousand power concentration. The Fresnel lens may be converging and bends incident light beams to converge on a collimator. A spectral separator follows, for example, at a forty-five degree angle to direct IR in one direction to an IR detector and pass UV/visible light to a UV/visible light detector so that the IR does not disrupt the collection of UV/visible. The present system preferably uses dual axis tracking of the sun as it moves across the sky to provide up to 40% higher electricity generation than fixed tilt ground mounted systems. Dual axis tracking typically involves the use of a first system for daily sunrise to sunset tracking and a second system for compensating for the height in the sky of the sun between winter and summer by tilting a solar panel. In a subsequent discussion of FIG. 13, dual axis tracking will be discussed further.
[0060] The second C stands for collimator 15, 515 which may use a diverging Fresnel lens or similar lens to straighten subtending solar rays and so collect diffuse light. As shown in FIG. 5, subtending light is transformed into collimated light by collimator 15, 515. In more plain language, the collimator may make crooked light straight for passing to a spectrum separator. The collimator assists in controlling the size or intensity of the light beam hitting each solar PV integrated circuit. Lack of control of the light, on the other hand, can cause the light to unintentionally reach parts of each integrated circuit or solar circuit card assembly. Over time, the concentrated light may diminish the production capability of the chip resulting in significant power losses. The collimator also may ensure that light is cast uniformly on the solar detector chips of two types (infrared and UV/visible). If the light is not collimated, the lack of uniformity in distribution can cause hot spots and/or structural moieties in the semiconductor.
[0061] A spectrum separator may be a cold (or hot) mirror having a dichroic film. In one embodiment, UV and visible solar radiation is separated from infrared solar energy. The UV/visible light energy is passed to a UV/visible photovoltaic device 850 which may be ten millimeters in diameter (circular) or, in another example, ten millimeters square or comprise one square centimeter, approximately, for ideally receiving an even uniformity of both bandwidth across the UV/visible spectra and intensity as will be discussed, for example, with reference to FIG. 10.
[0062] On the other hand, the spectrum separator may comprise a dichroic film for passing infrared radiation to an infrared photovoltaic cell 570 of similar size to that of the UV/visible PV cell or ten millimeters by ten millimeters (one centimeter in diameter if circular or one centimeter square if square). The concentrated light is split into UV/visible light and infrared radiation. The UV/visible light is directed to a double junction PV cell or integrated circuit assembly which may convert fifty-three percent of the UV/visible light into electricity. The infrared radiation may be directed to a p/n junction cell which may convert approximately thirty percent of infrared radiation into electricity. Conventional PV and concentrated PV (CPV) efficiency is reduced by the thermal effects of infrared photons. Thus, infrared radiation reduces efficiency by increasing the temperature of the cell which in turn reduces effective conduction of electrons thus reducing efficiency by ten to twenty-five percent on hot days. As a result of the five C's approach, the embodiments described herein may operate at a concentration ratio of approximately one thousand five hundred suns (or one thousand five hundred magnification), or even two thousand suns and generate electricity (using both infrared and UV/visible cells) at an efficiency of approximately forty percent compared with the state-of-the art eighteen percent.
[0063] FIG. 1 provides an overall system diagram showing a first embodiment of a radiant energy concentrator system including a spectral separator. Electromagnetic radiation 10, for example, radiant energy from the sun may transmit light onto a collimator 15 first or directly on to a Fresnel lens 20. Collimator 15 collects and multiplies energy incident on it by a predetermined factor. By electromagnetic radiation 10, for example, radiant energy from the sun is used herein to comprise polychromatic visible light, infrared, ultraviolet and all other energy received at the earth's surface from the sun either directly or by diffusion. A suitable collimator 15, 515, for example, may be one obtained from Remote Light Inc. of Colorado, which may multiply incident radiation by a factor of up to ten or more (as well as straighten crooked light, for example, diffuse light from around the collimator as received from the much larger Fresnel lens. In other words, in alternative embodiments, collimator 15, 515 may collect, receive and multiply radiant energy from, for example, sun source 10, (or alternatively, Fresnel lens 20 may first receive radiant energy from sun source 10), as will be explained further with reference to FIG. 3. Each of the collimator 15, 515 and Fresnel lens devices may be a multiplier and a capturer of incident solar direct or diffuse energy. If the Fresnel lens 20 receives radiant energy from sun source (direct or diffuse), it can multiply incident radiation by a factor of up to one thousand or more.
[0064] The collimator 15, according to FIGS. 1, 2 and 3 may multiply the received electromagnetic radiation 10 by a predetermined factor. The collimator 15 acts as a funnel or light pipe for capturing light received from various directions including reflected light from sunlight bouncing off a building. According to FIGS. 1, 2 and 3, collimator 15 collects and concentrates radiant energy for reception at Fresnel lens 20, for example, on the order of a factor of up to one hundred times or more. The approximate distance between collimator 15 and Fresnel lens 20 is on the order of two to five centimeters in one embodiment, depending on the collimator 15 and Fresnel lens characteristics and parameters.
[0065] Furthermore, for example, a converging Fresnel lens 20 may multiply the electromagnetic radiation it receives directly from the sun source one thousand times or from the collimator 15 by a further predetermined factor. In one example, if collimator 15 multiplies by up to ten or more and converging Fresnel lens 20 by up to one hundred or more then, incident radiant energy is multiplied by a total factor of up to one thousand or more. In an alternative embodiment, the concentrating Fresnel lens 20 may be a shaped Fresnel lens; (see the converging dome-shaped lens of FIGS. 6 and 7) having an approximately which concentrates both direct and indirect light onto a collimator 515 (or a diverging Fresnel lens 30). A dome-shaped lens combined with a square flat lens of approximately 400 mm by 400 mm and the circular dome having a circular footprint having a diameter in a range from 250 mm to 300 mm with 283 mm a preferred value, clearly outperforms a conventional flat converging Fresnel lens by laboratory testing as seen in the graph of FIG. 14 showing power of detector versus angle of incidence or degree by a factor of two and the detector is moved to a position of best focus where a ninety percent power on detector is measured between 0° and eight degrees AOI.
[0066] The domed Fresnel lens may be 400 mm×400 mm×3 millimeters and be manufactured of Polymethyl Methacrylate, a form of plastic. A cold mirror at either 35 mm×35 mm×3.3 mm or 25×25×3.3 mm may be constructed of borofloat glass from Schott AG of Mainz, Germany, with a dichroic film coating to reflect a preferred band, for example, IR and pass UV/visible. A custom negative lens may be matched with a domed Fresnel lens and a cold mirror at 35×35 millimeters and dimension A from the Fresnel lens to the detector is 419.5. Dimension B is the distance from the vertex of the custom negative lens to the detector at 39 millimeters and dimension C may be the midpoint between the cold mirror and the detector or sixteen millimeters per FIG. 15.
[0067] A conventional flat lens has been compared with a dome-shaped lens on a flat Fresnel lens surface and a twenty-five millimeters by twenty-five millimeters cold mirror and with a thirty-five millimeters by thirty-five millimeters cold mirror. With a 35×35 mm cold mirror, efficiency of energy conversion was greatly improved with a 10 mm×10 mm PV UV/visible detector. The hybrid solar concentrator provides high efficiency, low failure rate solar energy conversion in two separate solar bands, IR and UV/visible.
[0068] When a Fresnel lens is used as a concentrator, due to the light focusing characteristic of the Fresnel lens, a Fresnel lens is desirably used in conjunction with a motor system 80 or a plurality of light reflectors, not shown, for collecting and delivering the light to Fresnel lens 20 so that it may be further delivered without loss of radiant energy to system 30, 40, 50, 60, 70. The converging Fresnel lens 20, for example, may transmit light it receives onto a diverging Fresnel lens 30.
[0069] Converging Fresnel lens 20 and all elements shown below the Fresnel lens 20 in FIGS. 1 and 2 may be moved as the sun moves across the sky in the various seasons of the year (shorter or longer daylight hours) via a dual axis tracking motor system 80 controlled according to a sun calendar. A processor and associated software for motor control are not shown but may be used to program the motor system 80, for example, using GPS to identify the coordinates of a system according to the present invention to be installed. The motor system 80, in one embodiment, may be more conveniently used if the converging Fresnel lens 20 is used without a collimator 10. A similar motor system 80 is known, for example, from the field of telecommunications transmission and reception, for example, satellite tracking motor control systems with a difference being that the present system 80 may track the travel of the sun 10 or other source of electromagnetic radiation, if it is a moving source, for example, tracking the sun as it travels across the sky; (see FIG. 13).
[0070] As the light exits the diverging Fresnel lens 30, the light may be further collimated by a collimator not shown in FIG. 1 or 2, but see FIG. 3B. Visible and invisible light (for example, ultraviolet) exiting the Fresnel lens 30 of FIG. 1 or 2 may be transmitted through a spectrum separator, for example, a dichroic lens 40 and onto a solar photovoltaic cell 50 which produces electrical energy directly. The depicted spectrum separator 40 is shown at an angle of approximately 45°. In alternative embodiments, the angle may be between 20° and 80° depending on, for example, the desired location of a receiver such as a photovoltaic cell 50 or electrical or other energy accumulator 70 (for example, for accumulating heat energy). Accumulator 70 may, in one embodiment, comprise a steam or Stirling engine available from Edmund Scientific for generating an expanding liquid or gas. In another embodiment, accumulator 70 may be a conventional heat accumulator known in the art for receiving and accumulating infrared energy or may comprise a gallium antimonide (GaSb) p/n junction photovoltaic device doped with Zn and Te to convert infrared radiation to electricity at up to 30% conversion levels. Gallium arsenide may also be used in an alternative embodiment.
[0071] A plurality of stacked hot or cool spectrum separators, for example, dichroic lenses, 40 may receive light and transmit or reflect the light at different spectral bands to different photovoltaic cells 50 or accumulators 70 operable at different spectral bands at different receiving locations. On the other hand, infrared light may be reflected from the dichroic lens 40 either onto an accumulator 70, a further collimator, not shown, or is focused through an IR Fresnel lens 60 onto an accumulator 70. Moreover, in one embodiment, an array of 2×2 or other array of Fresnel lenses (FIG. 4, FIG. 12 or FIG. 13) and spectrum separators may direct infrared energy to a single, central accumulator 70. Thus, the depicted IR Fresnel lens 60 may be optional or useful to increase the overall electrical efficiency or for mechanical or chemical energy generation. The accumulator 70 then may, for example, either distill liquid, expand a working fluid, produce mechanical energy, generate thermal energy, convert hazardous waste into fuel and/or generate electrical energy.
[0072] FIGS. 3(A) to (C) show a plurality of embodiments utilizing collimator 15 and Fresnel lenses 20 in various combinations with hot or cold spectral separators 40. For example, FIG. 3A shows an embodiment where collimator 15 multiplies and collects radiant energy and transmits received, collected radiant energy to Fresnel lens 20a which focuses the radiant energy on spectral separator 40 which may be hot or cold. If separator 40 is hot, it passes infrared energy to be focused by further Fresnel lens 20c on to an accumulator 70 not shown below. Separator 40 reflects visible light toward Fresnel lens 20b for delivery to a photovoltaic cell 50 not shown. If a cold separator is used, the infrared energy is reflected by separator 40 and reflected toward Fresnel lens 20b at the right for focusing on an accumulator 70, not shown, proximate the spectral separator. UV/visible light is passed by cold separator 40 to a Fresnel lens 20c to a photovoltaic cell 50 below the spectral separator (not shown).
[0073] FIG. 3B may be similarly explained to one of ordinary skill understanding that FIG. 3B comprises Fresnel lens 20a as a first multiplier for transmitting radiant energy it receives to collimator 15. Collimator 15 pipes the received radiant energy to hot or cold separator 40, for example, a suitable dichroic filter. If separator 40 is hot, it passes infrared energy to be focused by further Fresnel lens 20c on to an accumulator 70 not shown below. Separator 40 reflects visible light toward Fresnel lens 20b for delivery to a photovoltaic cell 50 not shown. If cold, the infrared energy is reflected by separator 40 and reflected toward Fresnel lens 20b at the right for focusing on an accumulator 70 not shown. Visible light is passed by cold separator 40 to a Fresnel lens 20c to a photovoltaic cell 50 below (not shown).
[0074] FIG. 3C may be similarly explained to one of ordinary skill understanding that FIG. 3C comprises first Fresnel lens 20a as a first multiplier for transmitting radiant energy it receives to second Fresnel lens 20b as a second multiplier. Second Fresnel lens 20b transmits the received radiant energy to hot or cold separator 40, for example, a suitable dichroic filter. If separator 40 is hot, it passes infrared energy to be focused by further Fresnel lens 20d on to an accumulator 70 not shown below. Separator 40 reflects visible light toward Fresnel lens 20c for delivery to a photovoltaic cell 50 not shown. If cold, the infrared energy is reflected by separator 40 and reflected toward Fresnel lens 20c at the right for focusing on an accumulator 70 not shown. Visible light is passed by cold separator 40 to a Fresnel lens 20d to a photovoltaic cell 50 below (not shown).
[0075] FIG. 4(A) is a perspective view drawing showing a Fresnel lens system in the form of a two by two array for multiplying light and delivering the infrared portion of the spectrum to a single accumulator 70 at the center of a system of a two by two array of separators 40. FIG. 4(B) provides a side view of the system of FIG. 4(A) showing the steps of concentration, collimation separation and energy generation (where the concentration and collimation steps may be reversed). FIG. 4(B) may show a photovoltaic cell as a white box and an energy accumulator as a black box where only the black box is seen in bottom view FIG. 4(C). By using a collimator 15 (not shown) to collect diffuse radiant energy for each Fresnel lens 20 of such a system as depicted in FIG. 4(A), the overall efficiency of conversion of incident radiant energy to, for example, electric energy may be increased from a typical 18% to an efficiency in excess of 40% and, in one embodiment, in excess of 60%. Converging Fresnel lenses 20a, 20b, 20c and 20d are shown receiving incident radiant energy and delivering and multiplying received energy to a system as seen in FIG. 2 comprising, for example, at least a spectrum separator 40 for reflecting IR and a photovoltaic cell 50 for generating electricity. An accumulator 70, shaped as a central cylindrical column, receives infrared heat energy which may be converted to chemical or electrical or mechanical energy. Each photovoltaic cell has output leads 75 which may be collected and passed through an aperture in the planar base surface of the system.
[0076] One or a plurality of embodiments of a system such as may be seen in FIG. 4(A) through FIG. 4(C) may be mounted, for example, on the roof of a manufacturing facility with hazardous waste as an output. The visible spectrum may be used for generating electricity for running the plant and the infrared energy for use as heat and chemical energy for treating the effluent waste output and converting the waste to fuel, for example, a hydrocarbon fuel.
[0077] Now, a model of an embodiment of a high efficiency hybrid solar concentrator will be discussed with reference to FIGS. 6 through 11. The structure described simultaneous manages both heat and optics to achieve the most efficient conversion. Collimation is used to uniformly apply both intensity and color to reduce hot spots and structural moieties. Also, spectral separation reduces heat generation from UV/visible and infrared on both photovoltaic devices, thus reducing the heat load required to manage. Lastly, use of the Al (Aluminum) monoblock with heat fins and conventional heat dissipation easily radiates any excess heat from the system which produces a high efficiency, low cost solar technology. For example, the Fresnel lens system may be 40 centimeters by 40 centimeters while the IR or UV/visible chip size is one cm.sup.2. This results in a multiplication of one thousand six hundred between the lens system area and the chips' area, and as per FIG. 10, a uniform distribution and high efficiency of solar energy conversion to electrical energy leaving little heat energy to dissipate by the conventional means.
[0078] FIG. 6 shows in perspective view a domed Fresnel lens 620 for capturing direct sunlight as well as diffuse light from the sun and outputting and concentrating the light like a funnel for reception at collimator 615 in a structure comprising brackets 645 for holding a collimator/separator/PV cells assembly seen in FIG. 6 only as collimator 615. As can be seen from FIG. 6, the domed Fresnel lens 620 comprises a circular domed portion and a flat square portion for focusing received light on collimator 615. The lens may be constructed of Polymethyl Methacrylate, be 400 mm by 400 mm by 3 mm where a flat Fresnel lens portion may have a 0.5 mm pitch. The range in size may be between 200 mm×200 mm and 500 mm×500 mm. A typical range of ratio then is from 400 to 2500×. Given that in one embodiment 400 mm is forty centimeters, the overall area is 40×40 or 1600 cm.sup.2. Also, given that the size of PV cells is one cm.sup.2, the overall size of the Fresnel lens system is one thousand six hundred times the size of either a UV/visible multijunction chip or a IR p/n junction chip, both with high electrical coversion and little residual heat and so high concentration ratios are achieved on the order of one to two thousand (compared with the prior art at 40×).
[0079] FIG. 7 shows in side view the brackets 645 and the domed Fresnel lens 620 with electrical conductors coming from the bottom of an assembly for generating electricity (not shown) comprising the collimator, spectral separator (preferably cold), a UV/visible PV cell below and reflected IR is received by a IR p/n junction cell to the side.
[0080] FIG. 8 shows the assembly of a collimator 615, a spectral separator such as a cold mirror 840 for reflecting infrared energy to IR detector 870 seen as a first rectangular chip and a UV/visible detector or PV cell 850 below the spectral separator (cold mirror). The entire assembly is preferably provided with heat management. In particular, due to the high conversion of solar energy to electricity, there is little residual heat energy to disperse. Known heat dissipating techniques may be used to protect the assembly from reach such a temperature as 200° C. So, for example, a heat sink 885 as well as other known measures are taken for alleviating heat build-up and protecting the chips and circuit assemblies from damage. As already explained, there is a uniform distribution of the solar energy on either cell and the energy does not reach to circuit assembly components. Moreover, the IR energy is removed from the incident energy and converted separately to electricity from the remaining UV/visible energy.
[0081] FIG. 9 shows a side cut-away view of the assembly of FIG. 8 with the collimator 615 cut in half exposed at the top and with spectral separator 840 reflecting infrared to PV p/n junction 870 and UV/visible to a UV/visible PV cell only visible because of a bolt for fixing the cell to the assembly. Again, the assembly is shown having conventional heat dissipation such as including a heat sink 885.
[0082] FIG. 10 exemplifies the reception at a UV/visible PV cell that is 10 mm by 10 mm such that the combination of the domed Fresnel lens, the collimator, the spectral separator (for example, a cold mirror) provides an even uniformity of irradiance within a 10 mm diameter circle at best focus. Because of the combination, multiplication magnitudes on the order of one to two thousand power are achieved and because of the dark regions, the integrated circuit assembly of the PV cell is left undisturbed by damaging heat.
[0083] FIG. 11 provides a top view of an aluminum monoblock assembly with the collimator and spectral separator removed. What is left are the conventional heat dissipation represented by heat sink 885, the UV/visible PV cell 850 and the IR p/n junction cell 870 showing electricity generation at over 50% efficiency and heat conduction.
[0084] FIG. 12 shows an assembly of four such electricity generators with their respective dome-shaped Fresnel lens 620-1 through 620-4 at the top. The two by two array is preferred for forming a structure for following the sun as is seen by the embodiment of FIG. 13.
[0085] FIG. 13 shows dual axis tracking where a motor may track the sun from sunrise to sunset and a second motor may operate the North/South axis for tilting the structure of four cells to match the changing seasons and height of the sun in the sky.
[0086] FIG. 14 shows a graph of angle of incidence (AOI) measured against power on a detector such as a UV/visible detector for a domed Fresnel lens versus a conventional flat Fresnel lens, the graph showing a great increase in power over an AOI of zero to 0.2 degrees.
[0087] FIG. 15 shows the geometry of dimensions between lenses, cold mirrors and detectors where A is the distance from the Fresnel lens to the detector (in the case of a domed lens, the distance from the maximum sag to the detector, B is the distance from the vertex of a custom negative lens to a detector and dimension C is the midpoint of the cold mirror (spectral separator) to the detector. A custom negative lens is used and preferred over negative lens NT45922, a domed Fresnel lens is used with the dimensions given above and a cold mirror is used for reflecting IR and passing UV/visible. The domed converging Fresnel lens has a maximum transmission of approximately 89%. A preferred value of A is 419.5 mm. A preferred value of B is 30 mm, and a preferred value of C is 16 mm. Irradiance is defined as power divided by area. Including a transmission loss T associated with optics, irradiance E is equal to TP/A (where P is power and A is area). The maximum irradiance of the preferred embodiment is 0.0160 (with a 35 mm×35 mm cold mirror) and power is at 0.708.
[0088] All patents and articles referenced herein should be deemed to be incorporated herein by reference in their entirety as to their entire subject matter. One of ordinary skill in the art should only deem the several embodiments of a solar concentrator and conversion apparatus and method described above to be limited by the scope of the claims which follow.
