WO2013025380A1

WO2013025380A1 - Evacuated solar thermal electric generator

Info

Publication number: WO2013025380A1
Application number: PCT/US2012/049617
Authority: WO
Inventors: Mitchell Jay NEWDELMAN
Original assignee: Newdelman Mitchell Jay
Priority date: 2011-08-15
Filing date: 2012-08-03
Publication date: 2013-02-21

Abstract

An evacuated solar thermal electric generator is disclosed. The generator has a conductive heat receiving element having a heat receiving surface and a heat sink portion disposed away from the heat receiving surface. The generator has a heat resistant enclosure that includes a top encasing that is at least partially transparent, and a bottom encasing that is joined to the top encasing to create an airtight seal. The bottom encasing has a surface or cavity for receiving at least part of the heat receiving element such that at least part of the heat sink portion is in direct contact with the bottom encasing. A vacuum is provided in a space within the enclosure between at least a part of the heat receiving surface and the top encasing. A thermoelectric generating material is thermally coupled to the heat receiving element for conversion of solar thermal energy to electrical energy.

Description

Evacuated Solar Thermal Electric Generator

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation in part of U.S. Patent Application Serial No, 12/791,579 filed on June 1, 2010, the entire disclosure of which is mcorporated herein by reference in its entirety. This application also claims priority to United States Patent Application Serial No. 61/573,036 filed August 5, 2011 entitled "Evacuated Solar Thermal Electric Generator" by NewDelman, the entire disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1 . Field of the invention

[0001] This disclosure relates generally to solar energy, and. more particularly, to an evacuated solar thermal electric generator.

(0002]

2. Description of related art

[0003] The predominant way to generate electricity from solar energy is currently through photovoltaic materials. Photovoltaic materials are semiconductors such as monocrystalline silicon, polyerystalline silicon, amorphous silicon, as well as other materials like gallium arsenide and copper indium diselenide. Photovoltaic materials convert light directly into electricity at the atomic level. Materials that exhibit the photoelectric effect absorb photons and release electrons. This release of electrons can be captured and results in the production of an electric current by the photovoltaic material.

[0004] In addition to photovoltaic materials that convert light directly into electricity, a temperature difference in a material can also produce an electric potential. Materials that exhibit this phenomenon are known as thermoelectric materials. The Seebeck effect refers to the conversion of a temperature difference into an electric current. In the alternative, the Peltier effect refers to the conversion of electric current into a temperature difference.

[0005] Solar thermal energy collectors are currently a viable alternative energy solution. Currently, several major types of solar thermal energy collectors are known, including evacuated tube collectors, flat panel collectors and bulb type collectors. 10006] Bulb type solar collectors (BTC), such as that disclosed in U.S. Patent No. 4,084,576, utilize a bulb-style housing and a central spire to which sunlight is directed. Pathways are provided for a circulating heat exchanging medium (such as a gas or liquid) to absorb heat. BTCs have not gained widespread acceptance. The use of heat exchanging gas and/or fluid pathways make manufacture and use difficult, as extra energy must be provided to pump the gas and/or fluid, and considerations must be taken for possible engineering problems associated with heat conveying gasses and fluids being channeled through small diameter tubing. As a result, BTCs are not adaptable, scalable, nor easy or cheap to manufacture. These shortcomings of BTCs have limited their use and acceptance.

[0007] Flat panel or flat plate collectors consist of a simple heat-absorbing "black-box" (sometimes evacuated of air) that collects solar energy as heat and removes the heat using a heat- exchanging pipe or medium (such as a liquid or gas). Similarly, evacuated tube collectors or glass vacuum tubes (GVT) consist of a heat-absorbing medium (usually in the form of a 'U' type hollow tube or heat pipe) that is partially or fully inserted within an evacuated transparent glass tube. These collectors are usually installed in arrays where many such tubes are attached to a few heat exchanger manifolds, which utilize a heat exchanging method to carry away useful heat.

[0008] Both flat panel collectors and evacuated tube collectors suffer many deficiencies. Evacuated tube collectors are complicated to install and utilize a large amount of space, due to the arrangement of the tubes in the array. Additionally, the total area provided for solar absorption is low relative to the amount of space needed for the array, due to the need to enclose the absorber within a glass tube. Flat panel collectors are similarly cumbersome, and therefore difficult to install. A flat panel collector is typically not evacuated of air, resulting in large heat losses to the cooler ambient environment. Evacuating the flat panel collector to solve this issue is feasible but troublesome, as the flat panel collector uses a metal frame with a standard-sized glass pane position along a top surface (sometimes with a second glass pane on a bottom surface). They therefore require glass-to-metal vacuum seals, which will invariably result in loss of vacuum if ever the seal is broken.

[0009] Longevity is also an issue with evacuated tube collectors, as the vacuum integrity of cost-effective tubes is limited by the quality of the materials and components used in its manufacture and the evacuation techniques employed to generate the internal vacuum. As a result, even in the best cases, manufacturers typically guarantee no more than ten years of vacuum integrity unless highly expensive manufacturing materials and/or methods are used. Furthermore, both flat panel and evacuated tube type collectors require secondary considerations with respect to spatial positioning and life cycle. Therefore, their potential for integration into architectural design is practically nonexistent, due to their size and the logistics of their use. Both are difficult to install in or alongside the vertical fagade of structures, and neither is aesthetically pleasing.

[0010] While the capture and use of solar thermal energy is attractive due the environmental and cost benefits, fitting a building with appropriate heat transfer devices such as fluid filled tubing adds complexity. The ability to use captured thermal energy as electricity certainly increases the attractiveness of a thermal energy installation.

[0011] A solar thermal energy conductive device such as the one disclosed in United States Patent Application Publication Number US2011/0290235 Al that is adaptable in shape, scalable in size and aesthetically appealing, and that can be used not only for thermal energy collection but also, as described herein, for electricity generation, has not heretofore been disclosed or suggested in the art. BRIEF SUMMARY OF THE INVENTION

In one aspect of this disclosure, an evacuated solar thermal electric generator is disclosed. The generator comprises a conductive heat receiving element having a heat receiving surface and a heat sink portion disposed away from the heat receiving surface. The evacuated solar thermal electric generator further comprises a heat resistant enclosure that includes a top encasing that is at least partially transparent, and a bottom encasing that is joined to the top encasing to create an airtight seal. The bottom encasing having a cavity for receiving at least part of the heat receiving element such that at least part of the heat sink portion is in direct contact with the bottom encasing. A vacuum is provided in a space within the enclosure between at least a part of the heat receiving surface and the top encasing. Solar energy is transmitted to the heat receiving surface through the transparent top encasing and is transferred through the heat receiving element to the heat sink portion. A thermoelectric generating material is thermally coupled to the heat receiving element for conversion of thermal energy to electrical energy.

[0012] In another aspect of this disclosure, a method for making an evacuated solar thermal electric generator is disclosed. The method comprises providing a conductive heat receiving element having a heat receiving surface and a heat sink portion disposed away from the heat receiving surface. At least part of the heat receiving element is inserted into a cavity formed in a bottom encasing so that at least part of the heat sink portion is in direct contact with the bottom encasing. A thermoelectric generating material is thermally coupled to the heat receiving element and an electrical current carrying element is attached to the thermoelectric generating material. The bottom encasing is joined to a top encasing that is at least partially transparent to define a heat resistant enclosure and create an airtight seal. A vacuum is provided in a space within the enclosure between at least a part of the heat receiving surface and the top encasing. Wherein the generator is adapted to transmit solar energy to the heat receiving surface through the transparent top encasing and transfer the energy through the heat receiving element to the heat sink portion, the thermoelectric generating material that is thermally coupled to the heat receiving element in turn converts thermal energy to electrical energy.

[0013] In another aspect of this disclosure, a method of generating electricity is disclosed. The method comprises installing the solar thermal electric generator in a sun-facing facade of a structure.

The foregoing has been provided by way of introduction, and is not intended to limit the scope of this invention as defined by this specification, claims, and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by reference to the following drawings, in which like numerals refer to like elements, and in which:

[0014]

[0 151 FIG. 1 is an exploded cross sectional view of an exemplary evacuated solar thermal conductive device;

[0016] FIG. 2 is a cross sectional view of the solar thermal conductive device of FIG. 1 installed on a heat exchanging device;

[0017]

[0018] FIG. 3 is a bottom view of an illustrative configuration of heat sink sections protruding from the bottom of the evacuated solar thermal conductive device;

[0019]

[0020] FIG. 4 is a bottom view of an alternate illustrative configuration of heat sink sections protruding from the bottom of the evacuated solar thermal conductive device;

[0021]

[0022] FIG. 5 is a cross sectional view of another exemplary embodiment of the evacuated solar thermal conductive device;

[0023]

[0024] FIG. 6 is a cross sectional view of another exemplary embodiment of the evacuated solar thermal conductive device; [0025} FIG. 7 is an exploded cross sectional view of an exemplary evacuated solar thermal electric generator;

[0026]

[0027J FIG. 8 is a bottom view of an exemplary evacuated solar thermal electric generator;

[0028]

[0029] FIG. 9 is a typical installation of an exemplary evacuated solar thermal electric generator;

[0030] FIG. 10 is a perspective bottom view of an exemplary evacuated solar thermal electric generator; and

[0031] FIG. 11 is a perspective top view of an exemplary evacuated solar thermal electric generator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For a general understanding of the present invention, reference is made to the drawings, i the drawings, like reference numerals have been used throughout to designate identical elements.

The present invention will be described in connection with a preferred embodiment; however, it will be understood that there is no intent to limit the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by this specification, claims, and the attached drawings.

Disclosed is a solar thermal electric generator that builds upon the novel Evacuated Solar Thermal Conductive Device of NewDelman, as disclosed in United States Published Patent Application Number US201 1/0290235, the entire disclosure of which is incorporated herein by reference.

[0032] United States Published Patent Application Number US201 1/0290235 to NewDelman discloses a new type of solar thermal energy conductive device, which may be referred to as a photonic heat sink (PHS). The PITS preferably includes a heat receiving element (HRE) having an internal heat sink instead of the conventional heat pipe or heat-exchanging medium. The heat sink may be attached to or integrally formed as a single component with the main heat receiving surface of the HRE. The HRE, with its heat sink and heat receiving surface, is preferably enclosed within a housing, which is preferably sealed and at least partially evacuated of air.

[0033] The resulting solar thermal conductive device or PHS is advantageous because there is no specific shape or size requirement for any single component of the conductive device. As a result, solar thermal conductive device units may accommodate any range of conditions. For example, the solar thermal conductive device units may be designed small enough so that a single installer could install an entire array of conductive devices with no specialized tools or lifting equipment. Alternatively, the conductive devices may be modified in size, shape, color and/or aperture to serve as a functional and aesthetically pleasing building facade (including artful designs or signage) composed of a plurality of such devices.

[0034] The ability to alter the shape of the housing, heat sink and heat receiving element makes the conductive device highly adaptable with respect to both energy production requirements and practical considerations for its installation and spatial usage. The overall shape of the solar thermal energy conductive device or PHS may be modified according to usage requirements. For example, the overall shape may be round, ovular, triangular, rectangular or some other complex or irregular shape. A preferred shape may be square or rectangular (essentially cuboid) with slightly rounded edges for ease of handling. In addition, one of the corners may be indented to allow for easy alignment, placement and removal of the PHS device for maintenance or installation purposes when such devices are installed in an array abutting one another. Alternatively, each edge may terminate in a sharp perpendicular edge so that, when laid side-by-side in an array, the PHS devices would present a generally smooth and flat surface, useful for, for example, an aesthetically pleasing building facade.

[0035] The use of a heat sink instead of the more common heat pipe or heat exchanger (such as a fluid or gas) makes the PHS device far simpler to manufacture, increasing cost effectiveness, modularity, and longevity, while reducing complexity. Additionally, the use of a glass-to-glass seal in the outer enclosure also improves the longevity of the internal vacuum, as effective glass- to-glass seals are easy to produce compared to glass-to-metal seals, such as those used in evacuated flat panel type collectors. Finally, the alterability of the shape of the heat receiving element (HRE), in conjunction with the ability to fill a large portion of the housing with the heat receiving element ensures a large ratio of surface area for receiving solar energy (e.g. via the aperture) relative to the space required to install the solar thermal energy conductive device.

[0036] Referring now to the drawings, FIG. 1 illustrates a preferred evacuated solar thermal conductive device or PHS 100. The device 100 preferably includes an enclosure 100a formed from a top hemisphere encasing 101 and a bottom hemisphere encasing 102. The top hemisphere encasing 101 preferably has a dome-like shape, with the slope of the dome falling off at a gradient as it tapers down to the edge. This configuration may be advantageous for allowing sunlight into the enclosure 100a from a wide range of angles and at various latitudes north or south of the equator, which may be useful if the solar thermal conductive device 100 is to remain static while the sun traverses the sky over the course of the day (as a result of the earth's rotation). Top hemisphere encasing 101 may be formed of any translucent high heat-resistant glass or glass-like material. The glass may be, for example, completely clear, or colored for aesthetic purposes and may be flat, convex, concave or even angular such as a pyramid or even a hemisphere of a regular or irregular geodesic form. Pyrex™ is a commercially available transparent and heat-resistant material, which may be used to form top hemisphere encasing 101. Alternatively, thick tempered glass (such as the glass utilized in older sealed-beam headlamps) may be utilized, as it has high resistance to incidental and/or weather damage (e.g. , rocks and hail). The material is preferably selected to withstand both the external and internal environmental conditions to which the solar thermal energy conductive device 100 will be subjected. |(K)37] Bottom hemisphere encasing 102 may also be formed of any glass or glass-like material, and may be opaque or translucent according to the needs of the end user. Bottom hemisphere encasing 102 may also include an optional reflective coating 104, which preferably extends around at least part of the interior circumference of the bottom hemisphere encasing 102 (as depicted in FIG. 1) to redirect additional solar light towards an encapsulated heat receiving element (HRE) 105. Alternatively, the reflective coating 104 may be installed around at least part of an external circumference of the bottom hemisphere encasing 102 (as depicted in FIG. 2). The reflective coating 104 is preferably made of any suitable reflective material with the ability to withstand the environmental conditions within or without the enclosure 100.

[0038] The heat receiving element 105 forms the core of the solar thermal conductive device 100. The heat receiving element 105 preferably includes a heat receiving surface 106 and one or more heat sinks 107. The heat receiving surface 106 and one or more heat sinks 107 may be integrally formed as part of a the heat receiving element 105, or they may be separate pieces joined together in a conventional manner, such as, for example, bonding, fastening, welding, soldering, cladding, etc. Solar energy, in the form of light, may strike the heat receiving surface 106, heating the heat receiving surface 106. This absorbed heat is transmitted by conduction in a direction toward the one or more heat sinks 107.

[0039] The heat receiving element 105 is preferably made of one or more conductive materials, such as (but not limited to) copper, iron, steel or aluminum. A combination or alloy of such materials may also be used, if desired. Other materials may also be utilized according to usage requirements. For example, weight restrictions, cost, materials availability and other considerations may limit the possible materials with which to create the heat receiving element

105. New or currently undiscovered exotic and/or non-traditional conductive materials (such as, for example, graphene on a metal substrate and unidirectional conductive polymers) are also contemplated, and may be utilized to make the heat receiving element 105 as technology and understanding advances. Additionally, heat sinks 107 are preferably shaped according to end user requirements, and may be of any configuration, such as (but not limited to) fingers, protrusions, fins, flanges, etc. as appropriate to maximize, for example, spatial utility or conduction, convection and/or thermal radiation in the selected heat exchanger. In the preferred embodiment, heat sinks 107 preferably protrude away from the main body 105a of the heat receiving element 105.

[0040] The heat receiving element 105 may be colored via an external coating or a material selected to form the body of the heat receiving element 105 (or some combination thereof). Alternatively, the top hemisphere encasing 101 may be wholly or partially tinted or otherwise colored. In this manner, an array of PHS devices 100 with one or more colors may then be installed on a fagade in an arrangement, creating an aesthetically pleasing colored facade, visual image, pattern, etc. While black is clearly a preferred color in terms of maximizing the amount of absorbed light (and therefore heat), other hues, such as (but not limited to) red, green, blue, etc. may also be utilized in conjunction with an acceptable reduction in heat absorbing efficiency, balancing a need to be aesthetically pleasing while remaining practical as an energy collecting array of PHS devices.

[0041] Positioning the point of heat transfer (i.e., the portion of the heat sink 107 in contact (direct or indirect) with a heat exchanger) away from the main body 105a of the solar thermal energy conductive device 100 may be advantageous as it forces heat to travel away from the main body 105a in a direction towards the heat sink 107. Additionally, the preferred PHS design eliminates many serious impediments associated with current solar technologies utilizing an internally circulating liquid or gas heat exchanger medium usually confined in a small diameter tube or conduit. Because the solar thermal energy conductive device 100 does not need to account for impediments caused by the use of an internally circulating liquid or gas (such as changing mechanical pressure), engineering and manufacturing the solar thermal energy conductive device 100 is simplified over preexisting devices. As a result, the solar thermal energy conductive device 100 is highly scalable, both in shape, color and usage.

[0042] The heat receiving element (HRE) 105, like the enclosure 100a, may be shaped according to the needs of the end user. The heat receiving surface 106 of HRE 105 is preferably configured to maximize the surface area available for receiving solar energy. For this reason, the heat receiving surface 106 may be configured to take up the maximum amount of space available in the lower hemisphere encasing 102, or the lower hemisphere encasing 102 may be molded to conform to the final shape of the heat receiving element 105, as depicted in the illustrative embodiment of FIG. 2. Preferably, the top outer edge of the heat receiving element 105 does not extend laterally beyond the top perimeter of the bottom hemisphere encasing 102 to avoid difficulty during manufacturing, particularly with respect to the creation of vacuum 201 (described below) within the interior of enclosure 100a.

[0043] Once both components are formed, heat receiving element 105 may be inserted or pressed into the bottom hemisphere encasing 102 during assembly of the PUS device 100.

Alternatively, heat receiving element 105 may be inserted or pressed into a molten, still pliant bottom hemisphere encasing 102 (if the materials and manufacturing logistics allow), causing the bottom hemisphere encasing 102 to conform to the shape of the heat receiving element 105 and create an even greater airtight fit between the heat receiving element 105 and the bottom hemisphere encasing 102. In either case, insertion of heat receiving element 105 preferably leaves no space between the heat receiving element 105 and the internal surface of the bottom hemisphere encasing 102.

[0044] Top hemisphere encasing 101 and bottom hemisphere encasing 102 may be joined or fused together to define a seam 103, which preferably extends around the entire circumference of both top hemisphere encasing 101 and bottom hemisphere encasing 102 to form an airtight seal. As mentioned earlier, top hemisphere encasing 101 and bottom hemisphere encasing 102 may have any desired shape. However, it is preferable that their perimeters along the edge of seam 103 be similarly shaped (if not identical) to ease the process of sealing the enclosure 100a. Sealing may be accomplished according to conventional techniques known in the art, dependent on the material (or materials) selected to create top hemisphere encasing 101 and bottom hemisphere encasing 102. Seam 103 is preferably strong enough to hold and support an evacuated vacuum 201 within the interior of enclosure 100a. Vacuum 201 preferably encompasses at least the entirety of the heat receiving surface 106. As mentioned above, by enclosing the entirety of the heat receiving surface 106 within vacuum 201, heat dissipation to the cooler ambient environment outside the top hemisphere encasing 101 is substantially reduced. Any type of vacuum generating device or method may be utilized to create vacuum 201 within the interior of the enclosure 100a. For example, a "gettering" type vacuum pump may be utilized, as it may achieve a considerably longer vacuum life span relative to other vacuum generating processes (such as the vacuum generated in a sealed, enclosed space by mechanical pump),

[0045] Alternative forms of the heat receiving element 105 are also contemplated, including hollow elements filled with components that enhance certain characteristics of the heat receiving element 105. For example, the heat receiving element 105 may be hollow and filled with a gas, liquid, polymer or even thermoplastic plasma (or some combination of the above) to enhance conductivity and/or reduce weight. Alternatively, openings may be formed in the sections of the hollow heat receiving element 105 that are in contact with the vacuum region 201 of the enclosure 100a, which preferably reduces the weight of the PHS device 100 without impeding the overall heat conductivity of the device.

[0046] In another alternative embodiment, the heat receiving element (HRE) 105 is formed with a mushroom- like shape. The dome/cap of the HRE 105 receives and absorbs sunlight, and transmits heat energy via conduction in a direction toward the stem-like heat sink of the HRE. which passes the heat energy on to a heat exchanger for recovery of energy (in a manner similar to the embodiment depicted in FIG. 6). No specific form is required, as the physical shape and configuration of the disclosed solar thermal energy conductive device 100 is intended to be flexible to accommodate a wide variety of needs and uses. Even heat resistant (tempered) flat glass could be used partially or entirely with top and bottom (and glass side elements if the top and or bottom are flat) fused to form an internal space capable housing the HRE and capable of being evacuated.

[0047] The heat receiving element 105 may also be coated with a coating that aids heat absorption. One particularly advantageous coating may be niobium (Nb), which has excellent solar thermal heat absorption qualities. Other rare absorption metals (or metal alloys) may be also be used as desired, such as (but not limited to) titanium (Ti), zirconium (Zr). hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), barium (Ba), vanadium (V). tantalum (Ta), thorium (Th), etc.

[0048] FIG. 2 illustrates the assembled solar thermal conductive device or PHS 100 installed in a heat exchanging device 200. The solar thermal energy conductive device 100 may be used with (or adapted to be used with) many possible forms of heat exchanging devices 200, including heat manifolds or other similar heat transport devices (such as, for example, a device known as a "header") that can be used to store or transport the solar thermal heat collected by the PHS device 100. Preferably, the heat exchanging device 200 and solar thermal energy conductive device 100 can be mated or otherwise coupled directly to one another. In the preferred embodiment illustrated in FIG. 2, the lower portion (including heat sinks 107) of the solar thermal energy conductive device 100 is preferably inserted or pressed into a prefabricated slot or groove 202 formed in the heat exchanging device 200 to thereby form a tight fit between heat exchanging device 200 and the solar thermal energy conductive device 100. The solar thermal energy conductive device 100 may be secured to the heat exchanging device 200 utilizing any suitable known technique or mechanism 203, such as (but not limited to) the use of pressure clips, O-rings, clamps, screw-downs and other conventional locking mechanisms. Mechanism 203 may complement or, preferably, double as an air and water tight seal to prevent contamination of the contact surface 202 or interior of the heat exchanging device 200. The external walls of heat exchanging device 200 are also preferably insulated with insulating layer 200a in a conventional manner to better retain heat and minimize heat loss while transferring the collected heat away from the PHS device 100. For example, layer 200a may constitute a small outer insulating casing, wrapping or coating that covers the exposed surfaces of heat exchanging device 200.

[0049] Heat exchanging devices 200 may take the form, for example, of a specially designed and engineered sun-facing wall of a building facade, where the wall itself holds PHS devices 100. PHS devices 100 may be fitted/installed from either side, but all preferably protrude to its exterior to allow light to reach the heat receiving elements 105. Heat sinks 107 preferably protrude into the interior of the wall for insertion into a heat-exchanging manifold that is affixed to or built into the interior side of the wall. Alternatively, the heat-exchanging manifold may comprise the wall itself, wherein an outer wall and inner wall encapsulate a space for collecting heat. The space may include a heat-exchanging medium (such as, for example, a fluid, gas, etc. ) for carrying the collected heat, which may be used for heating and or cooling the building, or for generating electricity by venting the collected heat through a turbine.

[0050] FIGS. 3 and 4 arc bottom perspective views of two illustrative configurations of heat sinks 107. In the two illustrative configurations, heat sinks 107 (and the accompanying portion of the bottom hemisphere encasing 102) extend down and away from the main body 105a of the HRE 105 of the solar thermal energy conductive device 100. Such a configuration is preferable when the solar thermal energy conductive device 100 is to be installed into a heat exchanging device for heat exchange, wherein the heat sinks 107 must protrude away from the body of the PHS device to make contact with a heat exchanger medium (such as a gas or liquid).

[0051] In FIG. 4, flow lines 401 illustrate possible avenues of fluid or gas flow around heat sinks 107 after the solar thermal energy conductive device has been installed in a heat- exchanging device. The heat sinks 107 may be positioned as to encounter the heat exchanger medium and force the medium to move around the heat sinks 107 (as represented by flow lines 401 ).

[0052] This preferably lengthens the contact duration between heat sinks 107 and the heat exchanger medium and may, therefore, increase the amount of heat removed to the exchanger per cycle. As stated earlier, any configuration of heat sinks 107 may be implemented as desired or necessary, as the PHS 100 allows for unique modularity in terms of shape, size and scale. 10053] It should be noted, however, that thermal shock may damage the solar thermal energy conductive device 100 (or its components) if, for example, it is suddenly exposed to low temperature heat exchanging fluid or gas after having reached a sufficiently high temperature. Therefore, measures should preferably be taken to avoid damaging thermal shock, such as (but not limited to) venting of excess heat or, preferably, maintaining constant contact between the solar thermal energy conductive device 100 and the heat exchanging medium to minimize the temperature differential between them.

[0054] FIG. 5 illustrates another embodiment of the evacuated solar thermal conductive device or PHS 100. Like the embodiment illustrated in FIGS. 1 -2, the PHS device 100 illustrated in FIG. 5 includes a top hemisphere encasing 101 and bottom hemisphere encasing 102, seam 103 and heat receiving element 105. However, unlike the previous embodiment, heat sink 107 preferably does not extend or project from the evacuated solar thermal conductive device 100. Instead, heat sink 107 may have a generally flat bottom surface. This configuration may be advantageous for connection to a heat receiving manifold designed to accommodate a shallow insertion of the solar thermal conductive device 100. Heat exchange would occur as heat exchanging fluid or gas passes along (and thereby contacts) the flat bottom of the solar thermal conductive device 100. However, vacuum 201 persists around the heat receiving surface

106 to prevent unwanted heat loss to the cooler ambient environment.

[0055] FIG. 6 illustrates another embodiment of the evacuated solar thermal energy conductive device or PHS 100, which may be advantageous for a user who desires the heat sink

107 to make direct contact with a heat exchanging medium. Like the other embodiments, the PHS device 100 includes a top hemisphere encasing 101 and bottom hemisphere encasing 102, seam 103 and heat receiving element 105. Vacuum 201 persists around the heat receiving surface 106 of the HRE 105 in the assembled PHS device 100 to prevent unwanted heat loss to the cooler ambient environment. However, heat sink 107 preferably includes a heat sink protrusion 107a, which extends beyond the bottom hemisphere encasing 102. The protrusion 107a may make direct contact with a heat exchanging medium when the solar thermal energy conductive device 100 is installed in a heat exchanging device. It is understood that the protrusion 107a as shown is illustrative. The protrusion 107a may take the form of any shape, size and penetrative depth required. For example, the protrusion 107a may be designed to help support or attach the PHS device 100 to or through a building wall/facade, or directly into a heat exchanging manifold, thereby reducing the mechanical load on the PHS device, or even eliminating the need for a separate means of attachment.

[0056] Additional considerations may need to be taken to maintain the internal integrity of this alternative embodiment of the solar thermal energy conductive device 100 illustrated in FIG. 6. For example, the vacuum 201 is ideally maintained by the extremely tight fit between the bottom of heat receiving element 105 (including protrusion 107a) and the internal surface of bottom hemisphere encasing 102. However, additional sealing/bonding may be required between bottom hemisphere encasing 102 and the base of protrusion 107a to maintain the air and water tight seal within the enclosure 100a. The shape of the PHS device 100 may be selected to enable a superior vacuum seal/bond between the bottom hemisphere encasing 102 and the protrusion 107a by maximizing the contact area between the bottom hemisphere encasing 102 and the receiving heat element 105 (as depicted in FIG. 6). The increased contact area available for creating the seal may provide a more long lasting or even quasi-permanent bond/seal relative to the bond/seal on a conventional evacuated flat panel collector. Additionally, a layer of material with diminished heat conduction properties may be interposed between the heat receiving element 105 and bottom hemisphere encasing 102 to further reduce the amount of heat that reaches the seal, thereby increasing the efficiency of the device.

[0057] Also depicted in FIG. 6 is an optional optical enhancer 601 formed on the top hemisphere encasing 101, which may serve to enhance the quantity or quality of light (via, for example, focusing) of sunlight striking the heat receiving surface 106 of HRE 105. Optical enhancer 601 may be implemented, for example, by a special material coating, specialized shaping of the top hemisphere encasing 1 1, texturing of the internal surface of top hemisphere encasing 101, fluting, magnification and/or focusing lens shapes, etc.

[0058] In an alternative embodiment, the PHS device 100 may be utilized to implement a "solar chimney," in which heat collected by way of a PHS device 100 (or an array of such devices) is vented to create electrical energy. When collected solar heat is not required and/or desired for use, excess heat may be collected and vented/redirected into a chimney style vent (using known chimney drafting techniques). The rising hot air may then drive a turbine located at or near the top of the vent to produce electricity. The vent structure may be affixed to or constitute part of a larger structure in which the PHS device(s) 100 is installed, such as a building. This configuration is advantageous because it allows one to control the operating temperature of the PHS device 100 (or an array of such devices) by allowing the venting of excess heat. Additionally, vented excess heat may be partially recaptured for use as electricity, supplementing and/or complementing the heat collecting function of the PHS device 100.

[0059] In an alternative embodiment, the top hemisphere encasing 101 may be bonded/sealed directly to heat receiving element 105, with the space between these elements defining an evacuated vacuum region. The efficacy of this embodiment is dependent upon the quality of the glass-to-metal seal. [0060] Turning now to FIG. 7, an exploded cross sectional view of an exemplary evacuated solar thermal electric generator is depicted. Various embodiments of the solar thermal conductive device of NewDelman have been disclosed herein. The novel solar thermal conductive device according to NewDelman is modified to produce electricity from the thermal heat that has been collected by the device. This allows for a modular and efficient source of electricity in applications such as building exteriors, facades, and the like. A thermoelectric generating (TEG) material is attached to the back side of the solar thermal conductive device of NewDelman where in use it will experience a temperature gradient between the heat sink of the solar thermal conductive device of NewDelman and the cooler air of the inwardly facing (as applied to a building, for example) surface of the thermoelectric generating (TEG) material. It should be noted at this point that the thermoelectric generating (TEG) material may be applied to the solar thermal conductive device of NewDelman either during manufacturing or as a retrofit to existing installations of evacuated solar thermal collectors. Examples of thermoelectric generating (TEG) materials include, but are not limited to, Bismuth chalcogenides such as Bismuth Telluride, Lead telluride, inorganic clathrates, magnesium group IV compounds, silicides, skutteradite materials, homologous oxide compounds, half heusler alloys, silicon- germanium alloys, various nanomaterials, and the like.

[0061J The exemplary evacuated solar thermal electric generator 700 of FIG. 7 is shown in exploded cross sectional view. The fundamentals of the underlying solar thermal conductive device having been previously described herein, the exemplary device depicted in FIG. 7 has a heat sink 107 that does not extend or project from the device. Other embodiments, as previously described and envisioned herein, may have heat sinks or heat receiving elements in various shapes, sizes, and may, in some embodiments of the present invention, extend or project from the device. The heat receiving element 105 may be formed from a conductive material such as copper, iron, steel, aluminum, or the like. The heat receiving element 105 may be cast, machined, or otherwise formed to fit the bottom hemisphere encasing 102. The heat sink 107 is in contact with the bottom hemisphere encasing 102 and heat transfer from the heat sink 107 through the bottom hemisphere encasing 102 is possible either through the materials themselves, or through the assistance of thermally conductive grease, vias, protruding or otherwise extending features, or the like. In addition, heat sink fins, honeycomb or mesh structures, bonding and heat transfer materials, nanopartieles and nanostructured materials, and the like, may be employed to facilitate heat transfer. Attached to the bottom hemisphere encasing 102 is thermal electric generating material such as the thermoelectric generating (TEG) straps 703 depicted in FIG. 7. The TEG straps 703 may be bonded directly to the bottom hemisphere encasing 102, or, in some embodiments of the present invention, the TEG straps 703 or a similar thermoelectric generating structure may be attached to another material and then fastened to the bottom hemisphere encasing 102. For example, the thermoelectric generating material may be applied to a film or coating and then to the bottom hemisphere encasing 102 to allow for ease of replacement or retrofit. This would allow for upgrades as thermoelectric generating materials improve, replacement of defective thermoelectric (TEG) structures, or upgrade from a thermal device to a thermoelectric generating device. Further, in some embodiments of the present invention, the thermoelectric generating (TEG) material may be directly printed or bonded to the bottom hemisphere encasing 102, and may, in some embodiments of the present invention, employ a material or process that allows for removal of the thermoelectric generating (TEG) material from the bottom hemisphere encasing 102. In addition, protective coatings may be applied to the thermoelectric generating (TEG) material to protect it from such factors as environmental conditions. The thermoelectric generating (TEG) material may be applied by bonding, coating, printing, mechanical attachment, or the like. An example of a suitable material and process is that which is disclosed in United States Patent 7,790,137 B2 to Xiao et al. and entitled "Metal Telluride Nanocrystals And Synthesis Thereof, the entire disclosure of which is incorporated herein by reference. While the thermoelectric generating material is depicted in FIG. 7 in the form of straps, other geometries and physical structures may also be employed. In some embodiments of the present invention, the thermoelectric generating (TEG) material is combined with a support structure such as a plastic support structure. In some embodiments of the present invention, the thermoelectric generating (TEG ) material is combined with other metals such as copper, for example copper pads, to allow for thermal and/or electrical connections. In some embodiments of the present invention, the heat receiving element 105 is thermally coupled to a heat exchanging device such as previously described herein, and a thermoelectric generating (TEG) material is thermally coupled to the heat exchanging device. The thermoelectric generating (TEG) material may be directly bonded or printed to the bottom hemisphere encasing 102 through a process such as thick film or 3D printing, mechanical bonding, chemical bonding, mechanical fastening (such as, for example, pressure clips) or the like. In addition, heat sink fins, honeycomb structures, bonding and heat transfer materials, nanoparticles and nanostructured materials, and the like, may be employed to facilitate bonding or fastening. The bottom hemisphere encasing 102 with thermoelectric generating (TEG) material may also be referred to as a bottom hemisphere thermoelectric generating (TEG) structure 701. Further, as used throughout this specification, the term "hemisphere" refers to a part of a whole three dimensional object, not necessarily a sphere and not necessarily a half of the three dimensional object. For example, the solar thermal conductive device and the solar thermal electric generator, as described, depicted, and envisioned herein, may be a sphere, but also may be a cube, a cuboid, a square based pyramid, a triangular based pyramid, a cone, a triangular prism, a cylinder, a rhombohedron, an irregularly shaped or amorphous three dimensional object, or the like.

[0062] Also depicted in FIG. 7 are standoff posts 705 and 707. FIG. 8 depicts, in addition to the first standoff post 705 and second standoff post 707, a third standoff post 709 and a fourth standoff post 71 1. These standoff posts are exemplary only, and may vary in shape, size, material, and quantity. The standoff posts may be made from a metal, a plastic, or other such structurally suitable material. As thermoelectric generating materials require a temperature gradient to operate, the standoff posts allow the evacuated solar thermal electric generator 700 to be mounted slightly away from a building or other surface to facilitate air movement and subsequent cooling of one side of the thermoelectric generating (TEG) material such as the TEG strap 703. In certain applications or conditions, supplemental mechanical ventilation such as fans or blowers may be required. Thermal gradients may also be created and used to develop airflow on the back side of the solar thermal electric generator. The standoff posts may be made of a metal, a plastic, or other suitable material and may be attached to the bottom hemisphere TEG structure 701 by way of adhesives. mechanical fasteners, supplemental mechanical fittings, chemical or thermal bonding, and the like.

[0063] In some embodiments of the present invention, the geometry of the solar thermal electric generator may be round, as depicted in Figures 7-11 , or may be of another geometry such as that of a square, rectangle, octagon, pentagon, hexagon, or the like. Size may also vary dependent on, for example, the application. In addition, geometries that resemble solar thermal flat panels may be employed. [§§64] Turning now to FIG. 8, a bottom view of an exemplary evacuated solar thermal electric generator is depicted. The bottom of the standoff posts can be clearly seen along with the TEG straps 703. The geometry of the TEG straps 703 may vary, and may, in some embodiments of the present invention, cover the majority of the bottom surface of the evacuated solar thermal electric generator 700. In some embodiments of the present invention, a single TEG strap may be employed, or a plurality of TEG straps, dots, disks, or the like, may be employed in other embodiments of the present invention. Any known type of waste heat dissipaters may be employed on the cold exterior side of the thermoelectric generator (TEG), such as loosely packed aluminum mesh that draws the waste heat away from the TEG to maintain a cold temperature differential with the hot side of the TEG that is against the exterior of the bottom hemisphere of the photonic heat sink (PHS) opposite the heat receiving element (HRE). Interconnecting the TEG straps 703 are electrical current carrying elements such as the series wires 803. Series wiring promotes cumulative voltage summation, and may be desirable in some applications. In other applications, parallel wiring is employed to increase the quantity of current provided while maintaining a voltage lower than that typically provided by series wiring. A wire outlet 805 is also depicted, which may include a connector or other termination device or structure. The wiring may be made from copper, aluminum, silver, gold, steel, or other suitable conductor. Further, the wiring may be of a single conductor or multiple conductors. In some embodiments of the present invention, a conductive ground plane may be employed that serves as a return path for current such that only a single wire is needed. In other embodiments of the present invention, multiple wires or multiple conductors are employed either in separate insulation jackets or as multi-strand wire. In still further embodiments, the electrical current carrying elements may be printed conductive traces, metal components, or the like. In addition, the wire outlet 805 may terminate on a connector or, in some embodiments of the present invention, may terminate on a standoff post that also serves as an electrical connector. A power inverter to convert direct current to alternating current may also be employed to convert the direct current from the thermal electric generator (TEG) straps 703 into alternating current for building related electrical power.

[0065] FIG. 9 is a typical installation of an exemplary evacuated solar thermal electric generator. A building 900, for example, may have a plurality of solar thermal electric generators 700 attached to its exterior. The solar thermal electric generators 700 may be configured in such a way as to provide aesthetic qualities to the building, thus providing "venustas" to buildings, walls, and related structures. The solar thermal electric generators 700 may take on various shapes, sizes, colors, and configurations to meet the aesthetic needs of the architect, building or structure owner, or similar interested party. In addition to purely aesthetic designs, the solar thermal electric generators 700 may be rendered into lettering, logos, or advertising. The solar thermal electric generator 700 may be installed in a partial or full sun- facing wall, roof, or the facade of any built structure. To facilitate installation, placement, or replacement of the solar thermal electric generators 700, a track mount 901 may be employed that provides placement and fixturing of each solar thermal electric generator 700 and also, in some embodiments of the present invention, provides for electrical power transfer through a series of bus bars that can be contacted electrically by way of posts, tabs, rails, or even the standoff posts of the solar thermal electric generator 700. This track mount 901 may, in some embodiments of the present invention, be similar to the track mounts used for track lighting and the like. While FIG. 8 depicts a wire outlet 805 to terminate the thermoelectric generating (TEG) straps 703, such a wire outlet 805 may terminate on a post, tab, rail, or the standoff posts to facilitate ohmic contact with the conductive bus bars of the track mount 901.

[0066] For a complete understanding of the evacuated solar thermal electric generator, FIG. 10 is a perspective bottom view of an exemplary evacuated solar thermal electric generator clearly showing the TEG straps 703, standoff posts, and associated wiring 803 and 805. A waste heat material such an aluminum mesh may be employed in some embodiments of the present invention (not shown). FIG. 11 is a perspective top view of an exemplary evacuated solar thermal electric generator. The bottom hemisphere encasing 102 is partially visible and the top hemisphere encasing 101 is clearly visible.

[0067] Various geometries, sizes, colors, features, and visual attributes of the solar thermal electric generator 700 may be envisioned after reading this specification with the accompanying drawings and claims, and such modifications are to be considered within the spirit and broad scope of the present invention and its various embodiments.

It is, therefore, apparent that there has been provided, in accordance with the various objects of the present invention, An Evacuated Solar Thermal Electric Generator. While the various objects of this invention have been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of this specification, claims, and the attached drawings.

Claims

What is claimed is:

1. An evacuated solar thermal electric generator comprising:

a conductive heat receiving element having a heat receiving surface and a heat sink portion disposed away from the heat receiving surface;

a heat resistant enclosure that includes a top encasing that is at least partially transparent, and a bottom encasing joined to the top encasing to create an airtight seal, the bottom encasing having a surface for receiving at least part of the heat receiving element such that at least part of the heat sink portion is in direct contact with the bottom encasing;

wherein a vacuum is provided in a space within the enclosure between at least a part of the heat receiving surface and the top encasing, and solar energy is transmitted to the heat receiving surface through the transparent top encasing and is transferred through the heat receiving element to the heat sink portion; and a thermoelectric generating material thermally coupled to the heat receiving element.

2. The solar thermal electric generator of Claim 1, further comprising an electrical current carrying element electrically coupled to the thermoelectric generating material.

3. The solar thermal electric generator of Claim 1, wherein the thermoelectric generating material is selected from the group consisting of Bismuth Telluride, Lead telluride, inorganic clathrates, magnesium group IV compounds, silicides, skutterudite materials, homologous oxide compounds, half heusler alloys, and silicon-germanium alloys,

4. The solar thermal electric generator of Claim 1, wherein the heat receiving element does not contact the top encasing.

5. The solar thermal electric generator of Claim 1, wherein at least an internal portion of the bottom encasing has a reflective coating.

6. The solar thermal electric generator of Claim 1, wherein the top and bottom encasings are made of heat resistant glass.

7. The solar thermal electric generator of Claim 1, wherein the heat sink portion is completely contained within the enclosure.

8. The solar thermal electric generator of Claim 7, wherein the cavity in the bottom encasing is configured to conforni to a shape of the heat sink portion so that the heat sink portion fits tightly within the cavity.

9. The solar thermal electric generator of Claim 1, wherein the heat sink portion is at least partially exposed outside the enclosure and the thermoelectric generating material makes thermal contact with the heat sink portion.

10. The solar thermal electric generator of Claim 1, wherein the heat sink portion includes a plurality of heat sinks projecting away from the heat receiving surface.

11. The solar thermal electric generator of Claim 10, wherein the bottom encasing includes a plurality of cavities, each cavity receiving one of the plurality of heat sinks and conforming to a shape of the received heat sink to provide for a tight fit between the received heat sink and the cavity.

12. The solar thermal electric generator of Claim 1, wherein the vacuum is generated by a gettering type vacuum pump.

13. The solar thermal electric generator of Claim 1 , wherein the heat receiving element is at least partially coated with a heat absorption material.

14. The solar thermal electric generator of Claim 13. wherein the heat absorption material comprises niobium.

15. The solar thermal electric generator of Claim 13, wherein the heat absorption material is selected from the group consisting of titanium, zirconium, hafnium, scandium, yttrium, lanthanum, barium, vanadium, tantalum and thorium.

16. The solar thermal electric generator of Claim 1 , wherein the heat receiving element is formed from a conductive material selected from the group consisting of copper, iron, steel and aluminum.

17. The solar thermal electric generator of Claim 1 , wherein the heat receiving element is thermally coupled to a heat exchanging device.

18. The solar thermal electric generator of claim 17, wherein the thermoelectric generating material is thermally coupled to the heat exchanging device.

19. The solar thermal electric generator of Claim 1 , wherein the heat receiving element is hollow.

20. The solar thermal electric generator of Claim 19, wherein the hollow heat receiving element contains a conductivity enhancing material.

21. The solar thermal electric generator of Claim 20, wherein the conductivity enhancing material is selected from the group consisting of a gas, liquid, polymer, graphene and thermoplastic plasma,

22. The solar thermal electric generator of Claim 19, wherein hollow portions of the hollow heat receiving element are in contact with the vacuum.

23. The solar thermal electric generator of Claim 1 , wherein the heat receiving element is coated with a material to achieve a desired color.

24. The solar thermal electric generator of Claim 23, wherein the material is niobium.

25. The solar thermal electric generator of Claim 1, wherein the heat receiving element is formed of a material to achieve a desired color.

26. The solar thermal electric generator of Claim 1, wherein the solar thermal electric generator is installed in a sun-facing facade of a structure.

27. The solar thermal electric generator of Claim 1, wherein the sun-facing encasing is at least partially tinted to achieve a desired color.

28. A method for making an evacuated solar thermal electric generator, comprising: providing a conductive heat receiving element having a heat receiving surface and a heat sink portion disposed away from the heat receiving surface;

inserting at least part of the heat receiving element into a surface in a bottom encasing so that at least part of the heat sink portion is in direct contact with the bottom encasing;

thermally coupling a thermoelectric generating material to the heat receiving element;

attaching an electrical current carrying element to the thermoelectric generating material;

joining the bottom encasing to a top encasing that is at least partially transparent to define a heat resistant enclosure and create an airtight seal; and

providing a vacuum in a space within the enclosure between at least a part of the heat receiving surface and the top encasing;

wherein the device is adapted to transmit solar energy to the heat receiving surface through the transparent top encasing and transfer the energy through the heat receiving element to the heat sink portion.

29. The method of Claim 28, wherein the heat receiving element does not contact the top encasing.

30. The method of Claim 28, further comprising coating at least an internal portion of the bottom encasing with a reflective coating.

31. The method of Claim 28, wherein the top and bottom encasings are made of heat resistant glass.

32. The method of Claim 28, wherein the heat sink portion is completely contained within the enclosure.

33. The method of Claim 32, wherein the surface of the bottom encasing is configured to conform to a shape of the heat sink portion so that the heat sink portion fits tightly within the cavity.

34. The method of Claim 28, wherein the heat sink portion is at least partially exposed outside the enclosure and the thermoelectric generating material makes thermal contact with the heat sink portion.

35. The method of Claim 28, wherein the heat sink portion includes a plurality of heat sinks projecting away from the heat receiving surface.

36. The method of Claim 35, wherein the bottom encasing includes a plurality of cavities, each cavity receiving one of the plurality of heat sinks and conforming to a shape of the received heat sink to provide for a tight fit between the received heat sink and the cavity.

37. The method of Claim 28, wherein the vacuum is generated by a gettering type vacuum pump.

38. The method of Claim 28, further comprising at least partially coating the heat receiving element with a heat absorption material.

39. The method of Claim 38, wherein the heat absorption material comprises niobium.

40. The method of Claim 38, wherein the heat absorption material is selected from the group consisting of titanium, zirconium, hafnium, scandium, yttrium, lanthanum, barium, vanadium, tantalum and thorium.

41. The method of Claim 28. wherein the heat receiving element is formed from a conductive material selected from the group consisting of copper, iron, steel and aluminum.

42. The method of Claim 28, further comprising coupling the solar thermal conductive device to a heat exchanging device.

43. The method of claim 42, wherein the thermoelectric generating material is thermally coupled to the heat exchanging device.

44. The method of Claim 28, wherein the heat receiving element is hollow.

45. The method of Claim 44, wherein the hollow heat receiving element contains a conductivity enhancing material.

46. The method of Claim 45, wherein the conductivity enhancing material is selected from the group consisting of a gas, liquid, polymer or thermoplastic plasma.

47. The method of Claim 44, wherein hollow portions of the hollow heat receiving element are in contact with the vacuum.

48. The method of Claim 28, wherein the heat receiving element is coated with a material to achieve a desired color.

49. The method of Claim 48, wherein the material is niobium,

50. The method of Claim 28, wherein the heat receiving element is formed of a material to achieve a desired color.

51. The method of Claim 28, wherein the top encasing is at least partially tinted to achieve a desired color.

52. A method of generating electricity comprising the step of installing the solar thermal electric generator of claim 1 in a sun-facing facade of a structure.