Solar Concentration and Cooling Devices, Arrangements and Methods
Arrangements may include a concentrator constructed and arranged to receive incident electromagnetic energy and to concentrate the incident electromagnetic energy to a greater intensity level; an electromagnetic receiving device comprising a first surface constructed and arranged to receive the concentrated electromagnetic energy, and a second surface opposite the first surface; a heat transport device comprising at least one duct and a first surface; and a thermal interface layer physically connected to at least a portion of the second surface of the electromagnetic energy receiving device and the first surface of the heat transport device, the thermal interface material being both electrically and thermally conductive. Related methods and additional arrangements are also described.
The present application is a continuation of, and claims priority pursuant to 35 U.S.C. §120 to, U.S. patent application Ser. No. 12/257,158 filed on Oct. 23, 2008, which claims priority pursuant to 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/996,273 filed Nov. 8, 2007; U.S. Provisional Application No. 61/071,410 filed Apr. 28, 2008; U.S. Provisional Application No. 61/071,411 filed Apr. 28, 2008; and U.S. Provisional Application No. 61/071,412 filed Apr. 28, 2008. The entire contents of each of which is incorporated herein by reference.
FIELDThe present invention relates to devices, arrangements and techniques for improved high-concentration conversion of electromagnetic energy, such as solar energy, to thermal energy and/or electricity with enhanced removal and/or transport of converted electromagnetic energy created at high concentration levels.
BACKGROUNDIn this specification where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.
Concentrating energy, such as solar energy, maximizes the ability to derive other forms of output therefrom. However, very high heat densities are often produced by sun concentrations of more than 1,000 times the nominal concentration of the sun's energy. This concentration is sometimes referred to as “1,000×” or “1,000 suns.” Some or all parts of an arrangement that are exposed to these levels of heat density may be destroyed or are rendered ineffective or inefficient. Consequently, at least some commercially available solar cells specify that they are not intended for use above 1,000 suns.
Moreover, conventional systems for achieving relatively high levels of solar concentration can require large and complex optical arrangements. Such arrangements often have a long focal length, and thus a large separation distance between the optics and the member receiving the concentrated solar energy. The size and complexity of such arrangements necessitates assembly of the various components in the field. Such assembly requires skill and precision, and adds to the overall cost of the system.
Therefore, it would be advantageous to provide improved structures, arrangements and techniques for cooling and heat transportation which have improved efficiency. In particular, it would be advantageous to provide such improvements in the areas of concentrated solar-thermal, photovoltaic and other concentrated solar electric power generation, as well as in other industries or applications such as the electronics industry. It would also be advantageous to provide adequate cooling under high solar concentration levels to prevent failure of concentrated solar systems and arrangements that may occur because of overheating. Finally, there is a need to provide concentrated solar-thermal, photovoltaic and other concentrated solar electric power generation arrangements with a simple, low-profile construction that enables rapid and cost-effective manufacture and assembly by mass-production techniques.
SUMMARYThe present invention may provide devices, arrangements, systems, and methods for improved heat transport, extraction, cooling, storage and management.
The principles and embodiments of the present invention can be utilized in conjunction with solar thermal, photovoltaic and other solar electric power generation applications.
The present invention may include devices, arrangements, and methods that generate very high heat densities. Such devices, arrangements and methods may include high heat densities produced by high sun concentration levels, such as 10× or more, 1,000× or more, 1,600× or more, 1,800× or more, 2,000× or more, or 10,000× or more.
According to one aspect, the present invention provides devices, arrangements and techniques that produce highly concentrated solar energy and directs that energy onto one or more solar cell, resulting in efficient energy conversion with fewer solar cells than an arrangement that lacks such high concentration levels. Thus, the present invention provides effective electrical power generation with a relatively lower cost per unit area.
According to a further optional aspect, the present invention provides efficient cooling or transporting of heat away from one or more solar cell, resulting in higher energy conversion efficiency. Thus, higher solar concentrations combined with efficient cooling or heat transport provides higher electrical power output per unit area of the solar cell, or solar cell array.
According to an additional aspect, the present invention provides an arrangement constructed to provide the above-mentioned performance benefits, while having a relatively low-profile form factor. The present invention can also provide a construction an arrangement which is suitable for manufacture by mass-production techniques, as opposed to relatively costly and laborious field assembly.
According to the present invention there is provided an arrangement comprising: a concentrator constructed and arranged to receive incident electromagnetic energy and to concentrate the incident electromagnetic energy to a greater intensity level; an electromagnetic energy receiving device comprising a first surface constructed and arranged to receive the concentrated electromagnetic energy, and a second surface opposite the first surface; at least one optical relocator constructed and arranged to re-direct concentrated electromagnetic energy onto at least a portion of the first surface; a heat transport device comprising at least one duct and a first surface; and a thermal interface layer physically connected to at least a portion of the second surface of the electromagnetic energy receiving device and the first surface of the heat transport device, the thermal interface material being thermally conductive, electrically conductive, or both.
According to a further aspect, the present invention provides an arrangement comprising: a photovoltaic solar cell comprising a first surface for receiving concentrated solar energy incident thereon, and a second opposing surface; a heat transport device comprising a first surface; and a thermal interface layer physically connected to the second surface of the solar cell and the first surface of the heat transport device, the thermal interface material being electrically and/or thermally conductive; wherein the arrangement converts the concentrated solar energy to at least 37 Watts of DC electricity/cm2 of photovoltaic cell area.
According to a another aspect, there is provided an array comprising: at least one concentrator, the at least one concentrator constructed and arranged to receive incident electromagnetic energy and to concentrate the incident electromagnetic energy to a greater intensity level; a plurality of electromagnetic energy receiving devices, each device comprising a first surface constructed and arranged to receive concentrated electromagnetic energy, and a second surface opposite the first surface; at least one optical relocator constructed and arranged to re-direct concentrated electromagnetic energy onto at least a portion of the first surface; at least one heat transport device comprising a first surface; and a thermal interface layer physically connected to at least a portion of the second surface of the electromagnetic energy receiving device and the first surface of the heat transport device, the thermal interface material being thermally conductive, electrically conductive, or both.
According to an additional aspect, the present invention provides an arrangement comprising: at least one concentrator constructed and arranged to receive incident electromagnetic energy and to concentrate the incident electromagnetic energy to a greater intensity level; at least one electromagnetic energy receiving device comprising a first surface constructed and arranged to receive the concentrated electromagnetic energy; a heat transport device in thermal communication with the at least one electromagnetic energy receiving device; and at least one optical relocator constructed and arranged to re-direct concentrated electromagnetic energy onto at least a portion of the first surface.
According to still another aspect, the present invention provides an arrangement comprising a circuit board comprising an upper electrically insulating layer having an opening disposed therein; an electromagnetic energy receiving device comprising a first surface having an active area and a second opposing surface, the active area in communication with the opening in the insulating layer; and a relocator comprising a member, the member comprising a first opening, a second opening, and converging side surfaces connecting the first and second openings, the side surface converging toward the second opening, the second opening disposed for direct communication with the opening in the insulating layer; wherein electromagnetic energy incident upon the relocator is directed onto the active area of the electromagnetic energy receiving device.
According to another additional aspect, the present invention provides an arrangement comprising a circuit board; and an array of solar cells disposed on the circuit board; wherein the solar cells of the array are electrically connected to at least one of the protection diodes, blocking diodes, or bypass diodes, in either a series or parallel relationship so as to provide a desired voltage and current combination.
According to an additional aspect, the present invention provides an arrangement comprising a circuit board comprising an upper electrically insulating layer having an opening disposed therein; an electromagnetic energy receiving device comprising a first surface having an active area and a second opposing surface, the active area in communication with the opening; an electrical contact area in electrical communication with the active area; an optical relocator comprising a member, the member comprising a first opening, a second opening, and converging side surfaces connecting the first and second openings, the side surfaces converging toward the second opening, and the second opening disposed for direct communication with the opening in the upper insulating layer; wherein electromagnetic energy incident upon the relocator is directed onto the active area of the electromagnetic energy receiving device.
Unless otherwise defined herein or in the remainder of the specification, all technical and scientific terms used herein have meanings commonly understood by those of ordinary skill in the art to which the present invention pertains.
Before describing the present invention in detail, it is to be understood that the terminology used in the specification is for the purpose of describing particular embodiments, and is not necessarily intended to be limiting. As used in this specification and the appended claims, the singular forms “a”, “an” and “the” do not preclude plural referents, unless the context clearly dictates otherwise. It is to be understood that reference herein to first, second, third and fourth components (etc.) does not limit the present invention to embodiments where each of these components is physically separable from one another. For example, a single physical element of the invention may perform the features of more than one of the claimed first, second, third or fourth components. Conversely, a plurality of separate physical elements working together may perform the claimed features of one of the claimed first, second, third or fourth components. Similarly, reference to first, second (etc.) method steps does not limit the invention to only separate steps. According to the invention, a single method step may satisfy multiple steps described herein. Conversely, a plurality of method steps could, in combination, constitute a single method step recited herein. In addition, the steps are not necessarily limited to the order in which they are set forth herein.
As used herein, the term “electromagnetic energy receiving device” means one or more devices arranged for receiving one or more forms of electromagnetic energy, such as solar energy, infrared energy, far infrared energy, microwave energy, sound energy, phonon energy, or radio waves, and converting the electromagnetic energy incident thereon to one or more forms of energy which differ than the form which is incident thereon. The converted energy may take the form of electrical current, heat, mechanical energy and/or fluid pressure. Such electromagnetic energy receiving devices include, but are not limited to, photovoltaic solar cells and passive solar thermal receptors.
As used herein, the term “heat transfer media” means a vapor, a single fluid, mixed fluids, or multiphase fluids. The heat transfer media may have any suitable pressure, including pressures equal to, less than, or higher than, atmospheric pressure. The heat transfer media may include, but is not limited to, one or a combination of: organic fluid, inorganic fluid, biological fluid, water, steam, oil, solid particles or structures of organic, inorganic or biological materials, and various sizes of particles or structures having micro- or nano-sized dimensions, including but not limited to tetrapods and millipods. When present in the form of a mixture, the heat transfer media may take the form of a colloidal dispersion or emulsion.
As used herein, the term “duct” shall mean one or more structures capable of containing or conducting the heat transfer media therethrough. The duct includes structures such as channels, canals, tubes, conduits, passageways, tubules and capillaries. The duct may be open or closed. The term “duct” is not limited to any particular material, cross-sectional geometry or dimension. For purposes of illustration, the duct can be provided with dimensions on the order of 1 nm to 10 cm.
DETAILED DESCRIPTIONAn exemplary arrangement formed according to the principles of the present invention is illustrated in
The arrangement 10 further comprises at least one electromagnetic energy receiving device 14. The electromagnetic energy receiving device 14 comprises a first surface 16 for receiving the concentrated electromagnetic energy EC thereon, and a second surface 18, opposite the first surface 16. The electromagnetic energy receiving device 14 can take any suitable form. For example, according to certain illustrative embodiments, the electromagnetic energy receiving device 14 can comprise one or more photovoltaic solar cell, or one or more thermal receptors. A thermal receptor receives the electromagnetic energy EC and converts it, primarily to thermal energy, which can in turn be captured in utilized for performing useful work such as heating water. Heated water can of course be used for number of different useful purposes, including powering steam turbines for generating electricity.
According to the illustrative embodiment of
According to yet another alternative, the heat transport device 20 may omit the heat transfer media, and simply radiate heat to the surrounding environment via any number of known configurations, such as external fins (see, e.g.,
The arrangement 10 may further include a thermal interface layer 24 physically connected to at least a portion of the second surface 18 of the electromagnetic energy receiving device 14, and to at least a portion of the first surface 22 of the heat transport device 20. According to certain aspects, there are no other intervening layers, components, or materials between the second surface 18 of the electromagnetic energy receiving device 14, the thermal interface layer 24, and the first surface 22 of the heat transport device 20. The thermal interface layer 24 preferably possesses high thermal conductivity. The thermal interface layer 24 optionally possesses high electrical conductivity as well. For example, the thermal interface layer 24 can have a thermal conductivity of 1 W/m*K up to 10,000 W/m*K, and optionally may have an electrical conductivity of 10 siemens to 10 micro-siemens, or more. The thermal interface layer 24 can be formed from any suitable material possessing the above-mentioned high thermal conductivity and high electrical conductivity. The thermal interface layer can be formed from one or more layers of a matrix of one or more combination(s) of a variety of multiphase material, with phase changing properties. According to nonlimiting examples, the thermal interface layer may comprise one or more of: a silver alloy, tin-indium alloy, tin-bismuth alloy, lead-free solder, liquid metal, liquid metal alloy, organic material, inorganic material, thermal grease, solder, polymer, various sizes of structures in micro, nano or other dimensions including tetrapods and millipods, and films of a variety of thicknesses, being at least thermally conductive to ensure an efficient heat transport path, which also may include electrical conductivity provided through the same or an alternate path, or portion of the path, as the thermal transport path. According to a further alternative embodiment, the thermal interface layer 24 can be formed from the designer composite material as described in copending provisional and non-provisional U.S. patent application Ser. Nos. 61/071,412 and 12/257,235 entitled “Composite Material Compositions, Arrangements and Methods Having Enhanced Thermal Conductivity Behavior.”
The thermal interface layer 24 can be provided with any suitable thickness, pattern, or geometry. According to one illustrative example, the thermal interface layer 24 comprises a relatively continuous layer that is 10 nm-5 mm in thickness having an area corresponding to the entire area of the second surface 18 of the electromagnetic energy receiving device 14.
When embodied in the context of a photovoltaic device or arrangement, the present invention is particularly effective or efficient in converting incident solar energy EI into electricity. For example, arrangements formed as described herein and according to the principles of the present invention are expected to produce electricity on the order of up to 400 W/m2 of photovoltaic system area, or more.
According to an additional embodiment of the present invention, an alternative arrangement 10′ formed according to the principles of the present invention is illustrated in
The assembly 10′ is illustrated at a first position in
A tracking system or assembly formed according to a further alternative embodiment which can be utilized in connection with the devices and arrangements of the present invention is illustrated in
An arrangement constructed according to a further optional embodiment of the present invention is illustrated in
The arrangement 100 may further comprise at least one electromagnetic energy receiving device, such as at least one photovoltaic solar cell 114. Any suitable photovoltaic solar cell can be used in conjunction with the arrangement 100. The photovoltaic solar cell 114 may comprise conventional electronic packaging components associated therewith. Alternatively, a photovoltaic solar cell 114 may have any such electronic packaging components removed therefrom, as is the case with the embodiment illustrated in
The photovoltaic solar cell 114 comprises a first surface 116 for receiving the concentrated solar energy EC thereon, and a second surface 118, opposite the first surface 116. According to certain embodiments, the arrangement 100 may include electrical contacts or connectors 140 which provide electrical communication between the least one photovoltaic solar cell 140 and another component of the arrangement, such as a printed circuit board 142.
According to the illustrative embodiment, the arrangement 100 further includes at least one heat transport device 120. The at least one heat transport device 120, preferably transports thermal energy away from the at least one photovoltaic solar cell 114. The heat transport device 120 can take any suitable form capable of performing the above-mentioned thermal energy transfer. The heat transport device 120 can implement either passive or active cooling techniques. Thus, for example, a heat transfer media can be circulated within the heat transport device 120 via at least one inlet 144 and at least one outlet 146, thereby forming an active cooling system. The heated media, once removed through the outlet 146 may optionally be circulated through a heat transfer device, such as a radiator (not shown), and returned via the inlet 144. The heat transport device 120 may optionally comprise at least one duct 138 therein. Heat transfer media may be circulated within the heat transport device 120, at least partially through the at least one duct 138. Alternatively, the heat transport device 120 can define a closed system containing a heat transfer media therein.
According to yet another alternative, the heat transport device may omit the heat transfer media, and simply radiate heat to the surrounding environment via any number of known configurations, such as external fins and the like.
The heat transport device 120 can be formed of any suitable material, preferably a material that has a high thermal conductivity value. Thus, the heat transport device 120 can be formed from any of the material described above in connection with heat transport device 20. The heat transport device 120 may also comprise a first surface 122.
The arrangement 100 may further include a thermal interface layer 124 physically connected to at least a portion of the second surface 118 of the at least one photovoltaic solar cell 114, and to at least a portion of the first surface 122 of the heat transport device 120. According to certain aspects, there are no other intervening layers, components, or materials between the second surface 118 of the electromagnetic energy receiving device 114, the thermal interface layer 124, and the first surface 122 of the heat transport device 120. The thermal interface layer 124 preferably possesses high thermal conductivity. The thermal interface layer 124 may optionally possess high electrical conductivity, and may possess any of the thermal and/or electrical performance capabilities discussed herein in connection with thermal interface layer 24. The thermal interface layer 124 can be formed from any suitable material discussed above in connection with thermal interface layer 24. The thermal interface layer 124 can be provided with any suitable thickness, pattern, or geometry. According to one illustrative example, the thermal interface layer 124 comprises a layer having a thickness of 10 nm-5 mm that is a continuous layer having an area corresponding to the entire area of the second surface 118 of the electromagnetic energy receiving device 114.
Mounting the at least one photovoltaic solar cell 114 directly on the heat transport device 120, without the typical ceramic substrate solar cell packaging, enables maximum heat transfer from the solar cell to the heat transport device 120. In addition, since the thermal interface layer 124 and the heat transport device 120 can both be electrically conductive, the entire second surface 118 of the solar cell 114 can form a main electrical contact or electrode. Making the heat transport device 120 as one leg of an electrical circuit provides an opportunity to enhance the cooling capability. While not wishing to be bound to any particular theory, improved cooling is believed to result from the following phenomenon. First, direct thermal phonon coupling (material lattice vibration) of the solar cell in contact with the heat transport device. Second, the direct flow of heat energy carrying free electrons from the solar-cell to the cool the heat transport device because the heat transport device is part of the electrical circuit (electron-electron energy transfer is faster
in transferring energy to induce progressive local lattice vibration which is slower). When the solar-cell converts the sun's electromagnetic radiation into electrons, the electrons carry away approximately 20% of the heat energy lowering the temperature an additional 20%. This energy is no longer heating the cell. This extra cooling was measured directly during experiments. Third, solar-cell packaging substrate is typically germanium, which is transparent to the longer wavelengths of the solar energy. These longer wavelengths cannot be utilized by the cell to convert to electricity and end up as heat. The invention provides a direct path for the longer wavelengths to pass through the solar cell to the cool heat transport device without heating the cell. Heat from the cells is quickly moved away from the junction with the heat transport device.
Alternatively, the present invention can be combined directly with conventional solar cell arrangements that include their standard ceramic substrate and/or mounting and still provide advantages and benefits due to the exceptional cooling and heat transport properties.
The electromagnetic energy receiving device(s) collect energy. This energy can be put to one or more primary uses: generating electric current directly from the incident energy and/or heating a working fluid or a heath transfer media, such as water. The heated working fluid or heat transfer media can optionally be used to produce electricity as well, such as by using it to drive turbines and the like.
Where the electromagnetic energy receiving device is a photovoltaic solar cell, the heat transport device can serve to transport heat away from the solar cell to keep the solar cell cool. Since the energy conversion efficiency of the cell is reduced for every degree centigrade of temperature increase above 25° C., by transporting heat away from the solar cell the cell maintains its efficiency in converting solar energy to electricity.
Depending on the application and customer requirements, it may be valuable to compromise on the electrical conversion efficiency by reducing/regulating the heat transfer media flow through and around the cells and cell package to collect more heat per unit of heat transfer media flow rate. For example, hot water can be produced for utility applications. For every degree increase in cell junction temperature achieved by reduced water flow rate and some recirculation of the water, there is a compromise in the electrical conversion efficiency, yet on the other hand, a gain in increased temperature of the water coming out of each cell.
Very high thermal conductivity composites and thin films can be used in cooling and heat transfer to efficiently move the heat from the junction of the solar cells to the heat transport device. Efficient thermal transfer coupling techniques are used to transfer heat from the conductive part to the convective part of the system.
An illustrative non-limiting embodiment of an arrangement including closed-type cooling construction is illustrated in
According to a further aspect of the present invention, an array can be formed, optionally from a plurality of the above described arrangements 100. One such array or module 200 formed according to the principles of the present invention is illustrated in
A plurality of electromagnetic energy receiving devices 214 are provided to receive concentrated electromagnetic energy EC. The electromagnetic energy receiving devices 214 can have any of the features or characteristics of the electromagnetic energy receiving devices 14, 114 described herein. The array or module 200 may comprise one or more electrical contacts 240 which commonly electrically connect all or some of the electromagnetic energy receiving devices 214. The contacts 240 may also be used to connect a plurality of modules 200 to one another. In addition, as described herein, the electromagnetic energy receiving devices 214 can be electrically connected with additional components, such as one or more printed circuit boards 242.
The plurality of electromagnetic energy receiving devices 214 are connected to one or more heat transport device 220. According to the illustrated embodiment, a single heat transport device 220 is associated with all of the electromagnetic energy receiving devices 214 of the array or module 200. However, it is contemplated that a different heat transport device can be associated with each individual electromagnetic energy receiving device to 214, or that a number of subgroups of electromagnetic energy receiving devices 214 each share a respective heat transport device. The at least one heat transport device to 220 can have any of the features or characteristics of the previously described heat transport devices 20, 120. Thus, as illustrated in
A thermal interface layer 224 is provided between a second surface of each electromagnetic energy receiving device 214, and a first surface of the at least one heat transport device to 220. The thermal interface layer 224 can have any of the features or characteristics of the previously described thermal interface layers 24, 124.
The array or module 200 may also be associated with a suitable tracking device, such as the tracking device 28 illustrated in
As illustrated in
The array or module 200 may possess a modular construction. Each module would contain concentrator, electromagnetic energy receiving, heat transport and thermal interface components. Thus, by selecting the number of individual modules which can be connected together, one can easily select and change the overall size of the array or module 200. An array 250 formed from a plurality of modules is illustrated in
Arrangements 600, 600′ formed according to additional aspects of the present invention are illustrated in
The arrangements 600, 600′ may additionally comprise at least one concentrator 604, 604′ for receiving incident electromagnetic energy SE. According to the illustrative, non-limiting example, the concentrator 604, 604′ may comprise one or more of the optical elements previously described therein. For example, the concentrator may comprise a multiple-lens Fresnel lens array panel. This panel may optionally be mounted in grooves 603 of a frame or support 612, 612′. This panel may be in the form of a one or two dimensional array. Thus, for example, the panel may be in the form of a planar or curved array. The concentrator 604, 604′ is configured to concentrate and focus high-intensity electromagnetic or solar energy 614 of up to or greater than 1000× or less than 10,000× onto one or more electromagnetic receiving device(s) 616. The electromagnetic energy receiving device(s) may comprise one or more photovoltaic solar cell. The electromagnetic energy receiving devices of arrangement 600′ are present, but not visible in
According to certain embodiments, the arrangements 600, 600′ or modules are designed, packaged and sealed for environmental protection while operating under extreme environmental conditions. The modules may be environmentally or hermetically sealed with a pressure balance to accommodate fluctuations and environment of conditions, such as temperature, pressure, moisture, etc. the overall design of the arrangements 600, 600′ may be designed for proper matching of the relative coefficients of thermal expansion between the components, parts and packaging materials which make up the arrangements or modules. As noted above, the concentrator 604, 604′, which may optionally be in the form of a panel, can be mounted in grooves 603 of a frame or support 612, 612′. According to certain embodiments, a seal is formed between the grooves 603 and those portions of the panel or concentrator 604, 604′ received therein. According to further embodiments, one or more sides of the module are sealed with cover plates 625 which can be secured in any suitable manner to the frame 612, 612′, such as by mechanical fasteners or adhesive. The cover plates 625 may optionally include a bead of elastomeric sealant or other gasket-like structure 630 to help improve the seal formed between the cover plates 625 and the frame 612, 612′. According to yet another optional embodiment, the arrangements 600, 600′ may optionally be provided with filters 640 that define a semi-permeable barrier between the outside environment and the interior portion of the module. The filters 640 served to provide an effective barrier to contamination, yet permit the external environmental pressure and pressure inside the module to equilibrate or fluctuate. According to one optional modification of this construction, the filters 640 may be replaced by substantially nonpermeable diaphragms which provide a barrier, yet also served to permit the pressures to equilibrate via flexure of the diaphragm inwardly are outwardly, as necessary.
To attain high-concentrations of solar energy requires accurate positioning of components to keep the solar rays focus on the solar-cells. To this end any suitable tracking system can be utilized in conjunction with the arrangements 600, 600′ including any of the tracking systems described herein. The arrangements 600, 600′ may additionally include one or more optical relocator 610, 610′ designed to re-direct possibly misaligned rays of energy onto a desired area of the one or more electromagnetic energy receiving device 616. It should be understood that any of the various embodiments described herein may optionally include a relocator device of the type described herein. In a more fundamental aspect, the relocator 610, 610′ comprises a member 617 constructed to re-direct incident electromagnetic energy SE onto at least a portion of a first surface of an electromagnetic energy receiving device 616. The member 617 may comprise a first opening 618, 618′, a second opening 619, and converging side surfaces 620 extending between the first opening 618, 618′ and the second opening 619. Thus, the member 617 may be narrower at the bottom relative to the top. Here, the “top” is the side closest to incident electromagnetic energy. The first opening 618, 618′ may be formed such that the diameter thereof is larger than the beam width of concentrated energy transmitted from the at least one concentrator 604, 604′. The second opening 619 may be sized such that it is slightly larger than at least a portion of the first surface of the one or more electromagnetic energy receiving device 616. The converging side surfaces 620 may be provided with any suitable geometry or configuration. According to non-limiting examples, the converging side surfaces 620 can be multifaceted, cup-shaped, frustoconical, or in the form of a regular or irregular polygonal frustum. The slope of the side surfaces 620 may all be the same, or may differ relative to each other. The slope of one or more side surfaces 620 may be constant or variable. According to further non-limiting examples, one or more of the side surfaces 620 may take the form of a curved shape, an irregular polygon, a triangle, a rectangle, a square, a trapezoid or other polygon. The converging side surfaces 620 may optionally be polished, anodized, or otherwise coated or treated so as to enhance the degree of optical reflection. According to an alternative embodiment, an optical material 623 having an index of refraction greater than air may be provided in the member 617 between the first and second openings 618, 618′, 619 which has the effect of additionally concentrating the incident electromagnetic energy. The optical material may comprise one or more of: plastic, acrylic material, quartz, glass, metal, semiconductor material, films and fluid-filled structures. According to yet another optional embodiment, at least a portion of the side surfaces 620 may be formed from or coated with a photovoltaic material 651, and electrically connected to the output of the arrangement 600, 600′ or device.
References made herein to photovoltaic material are intended to encompass any material for conversion of energy incident therein to electricity that can be applied as a coating. Illustrative, non-limiting examples include: cadmium telluridium, copper indium gallium diselenide, amorphous silicon, dye sensitized nano-sized titanium dioxide particles, and (poly(N-vinylcarbazole) PVK nano-composites.
According to an additional embodiment, the relocator comprises a plate 610, 610′ having a plurality of members 617 formed therein. The relocator plate 610, 610′ may be mounted within slots 607 of a frame or support 612, 612′. The relocator plate 610, 610′ can be formed by any suitable technique, such as by punching, molding or stamping. The relocator plate 610, 610′ can be formed from any suitable material such as a metal like an aluminum or aluminum alloy. Optionally, the plate may be coated with a material to enhance its reflective or optical properties, such as a metal oxide coating. Thus, the relocator plate 610, 610′ is capable of final solar concentration and/or image re-location. A misaligned energy beam enters first opening 618, is reflection down off the converging sides 620 of the member 617, and exits the second opening 619 where it is thereby re-directed to the desired location on an electromagnetic energy receiving device 616.
As a more general principle, any surface of any of the various components of the arrangements described in the present disclosure that is exposed directly or indirectly to solar or electromagnetic energy can be coated with a suitable photovoltaic material. Thus, the energy to electricity conversion for the arrangement is maximized. By way of example, the top surface 652 of a relocator plate (e.g., 610, 610′) can be provided with a coating 654 of any suitable photovoltaic material, such as those photovoltaic materials described above.
Additional advantageous aspects of the present invention can be gleaned by reference to the illustrative arrangement 700 depicted in
The area between the inner surface 809 and the outer surface 810 could contain or be formed from an optically transparent or opaque material. When the area is made up of opaque material, the inner surface is made of reflective surface accomplished with or without reflective coating, sputtering, etching, polishing or surface treatment. When the area between the inner surface 809 and outer surface 810 contains or is made from a transparent material, the transparent material could be doped to create graded refractive index so that the light falling on the inner surface is reflected back through total internal reflection. The light that falls on any part of the surface 809 is guided to the bottom opening 806 through total internal reflection to the electromagnetic energy receiving device 616. The inside surface 809 may also be at least partially made of, or coated with a photovoltaic material, so that any misaligned light could be converted to electricity.
As shown in
According to the illustrated embodiment, the multiple layer flexible circuit or board 900 is made of insulation 909, 912, and copper plated surfaces 910, 918, anode 911 and cathode 925. Referring to
As noted previously, the thermal interface material 923 can made of a high thermal conductivity composite with eccentric thermal conductivity of lateral thermal conductivity in the X and Y direction much higher than in the vertical Z direction, thus very efficiently spreading the heat to a large surface of 924 is achieved.
An additional optional embodiment formed according to the principles of the present invention is illustrated in
In order to further elucidate the benefits and advantages of the present invention, reference will now be made to the following illustrative, non-limiting examples.
EXAMPLESHeat greater than 100 W/cm2 occurs at concentrations of approximately 1,000 suns or more. It should be noted that electronic devices melt in seconds without proper cooling at this level of heat density.
It has been difficult to concentrate more than 600 suns on a solar cell of 1 cm2 in size, mainly because the heat density produced melts the solar cell, if efficient heat transfer techniques are not used.
A solar-cell testing apparatus, associated with sidereal solar tracking apparatus using a modified equatorial telescope mount was retrofitted with the following capabilities: The degree of solar irradiance was controlled with a series of masks having different aperture sizes, thereby allowing concentrations from 1-Sun to 1688-Suns to be produced. Solar energy was focused to an area of 1 cm2; the cell surface temperature was measured with a non-contact IR sensor; emf and ampere values of a single 1 cm2 solar cell at various X-suns was measured; and heat flux at various X-suns was also measured for system calibration.
A conventional solar cell was combined with a cooling arrangement formed according to the present invention. A conventional 1 square cm solar cell (commercially available from Spectrolabs Inc.) was utilized. One such solar cell was stripped of its packaging and attached to a thermal transport block formed of a copper alloy via a thin layer of thermal interface material formed from a silver alloy material. For comparison, another arrangement like the one described above was prepared, except the packaging of the solar cell was left intact. For purposes of comparison, a conventional solar cell assembly without the cooling arrangement of the present invention was utilized. These arrangements we evaluated at various X-suns using the above-described experimental set-up. The results of this comparison is summarized in the following Table I.
As evident from the above, significant gains in cooling and heat transport efficiency is obtained, relative to the conventional arrangement, by the present invention.
All numbers expressing quantities of ingredients, constituents, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about.” Notwithstanding that the numerical ranges and parameters set forth, the broad scope of the subject matter presented herein are approximations, the numerical values set forth are indicated as precisely as possible. Any numerical value, however, may inherently contain certain errors resulting, for example, from their respective measurement techniques, as evidenced by standard deviations associated therewith.
Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention. Terminology used herein should not be construed in accordance with 35 U.S.C. §112, ¶6 unless the term “means” is expressly used in association therewith.
Claims
1. An arrangement comprising:
- a concentrator constructed and arranged to receive incident electromagnetic energy and to concentrate the incident electromagnetic energy to a greater intensity level;
- an electromagnetic energy receiving device comprising a first surface constructed and arranged to receive the concentrated electromagnetic energy, and a second surface opposite the first surface;
- at least one optical relocator constructed and arranged to re-direct concentrated electromagnetic energy onto at least a portion of the first surface;
- a heat transport device comprising at least one duct and a first surface; and
- a thermal interface layer physically connected to at least a portion of the second surface of the electromagnetic energy receiving device and the first surface of the heat transport device, the thermal interface material being thermally conductive, electrically conductive, or both.
Type: Application
Filed: Apr 27, 2011
Publication Date: Aug 18, 2011
Inventors: KRS Murthy (San Jose, CA), Robert S. Block (Reno, NV), Allen J. Amaro (Fremont, CA)
Application Number: 13/095,564
International Classification: F24J 2/08 (20060101);