WO1980001438A1

WO1980001438A1 - Energy production and storage apparatus

Info

Publication number: WO1980001438A1
Application number: PCT/US1979/001157
Authority: WO
Inventors: E Gomez
Original assignee: E Gomez
Priority date: 1979-01-02
Filing date: 1979-12-31
Publication date: 1980-07-10
Also published as: EP0020758A1

Abstract

One energy production device is a current generator, which is located in a temperature gradient between a heat source region (32) and a heat sink region (34). The generator comprises a first continuous material (12) having thermoelectric characteristics and having a repetitive shape with one portion extending between the source (32) and sink (34) and the other portion (18) between the sink and source, and a second material having thermoelectric characteristics electrically connected with only one of said first or second portions of the first material. A thermopile (10) is thus formed and plating techniques can be employed to connect the second material to the first material in the repetitive first or second portions of the first material. In this way, the thermopile (10) is formed of a repetitive series of thermocouples. The conductivities of the two materials are substantially equal. The conductors (60), (62) of another form of the energy production device are joined at thermocouple junctions, (68), with the junction areas being relatively large compared with the normal cross-sectional area of the conductor elements. By providing large cross-sectional areas of the thermocouple junctions, reduction in resistance and heat concentration is achieved, so that the resulting thermocouple and thermopile (10) may easily be used for solar energy collection to produce an electrical current and voltage related to the available solar energy. Energy storage is accomplished for use with a thermoelectric generator in which thermopiles (34'') are provided. The source of solar energy (30'') irradiates upon the latent heat storage device (38'') to enable the heat to be stored at a relatively constant temperature to serve as the source of heat for a greater period of time than that which the solar source is providing energy. Apparatus is provided to enhance the temperature gradient in which the thermopile is located in order to increase the thermoelectric energy generated.

Description

Energy Production and Storage Apparatus

Technical Field

This invention relates to energy generation and storage devices. The invention is directed toward novel arrangements of thermocouple and thermopile elements for generation of energy and for an improved current generator.

Conventionally, thermocouples are formed of two wires or rods of different materials joined at respective junctions, with one of the junctions being a hot region, while the other is a cold region.

In accordance with well known principles, a thermoelectric voltage is formed between the junctions, and one of the materials is broken to form a set of terminals so that current can flow between the junctions and through the materials.

Thermocouples formed of conductor elements have been employed as temperature sensing elements in many types of environments, especially with cookware. One of the important aspects of these thermocouples is the effect of sensing of the temperature level, and such elements have been constructed with the junction between the conductors being as small as possible, in order to enable the junction to be in close proximity to the source of heat.

Current generators are conventionally constructed of well known components placed in a temperature gradient. Such components formed as a thermocouple can generate electric currents.

With the advent of the need to discover alternate sources of energy, solar energy has been considered a prime resource. Thermocouples and thermopiles are generally formed of semiconductor elements in various environments for utilizing the heat generated by the sun to form thermopiles which serve as a source of electrical current and voltage. Semiconductor materials have inherent disadvantages, especially relating to cost and resistance levels, so that the voltage generated in the elements often does not enable large currents to be developed. In other aspects, semiconductor materials are formed of precious metals, which are becoming increasingly difficult to obtain and increasingly expensive. The field of solar energy collection, storage and generation has been expanding greatly in the recent past. There are many different devices for collecting the energy of the sun, and these devices generally include a means for receiving the solar energy upon a plate of solar collectors, which solar energy is converted into other forms of usable energy. One of the active areas of present concern is the generation of electric power from solar energy, and the present invention is directed to this type of system. One of the conventional problems found in solar generators is the inability to provide thermoelectric power during low sunlight periods. An object of this invention is to provide an improved thermocouple formed of conventional conductor elements which are suitable for the generation of electrical energy from the sun.

Another object of this invention is to provide a newly improved current generator, which is easy to manufacture, inexpensive, and susceptible of being used in regions of heat and cold.

Still another object of this invention is to provide a thermoelectric generator utilizing solar energy, which is capable of producing thermoelectric power during periods of time when sunlight is unavailable.

Background Art

A novelty search has been conducted and the following five references are believed to be the most relevant references discovered with regard to the instant inventionof the thermocouple.

3,023,257 E. W. Fritts Feb. 27, 1962

3,130,084 S. J. Loring April 21, 1964

3,434,203 W. Thorp March 25, 1969

3,879,229 W. Gilbert April 22, 1975

3,981,751 Z. Dashevsky et al Sept. 21, 1976

The patent to Fritts discloses thermocouples formed of semiconductor elements employing copper conductors 19 to connect the thermocouple elements. The present invention differs from the Fritts disclosure in many regards, especially relating to the utilization of conductor elements, which are different in cost and composition from the semiconductor elements used by Fritts. Further, the present invention provides for large junction areas with the large area junctions being formed by the mating surfaces at the hot and cold junctions of the thermocouple.

The patent to Loring is generally directed to a solar thermoelectric generator employing a parabolic heat reflector to concentrate the heat at the hot junction portion 11 of the thermocouple 10. The thermocouple is formed by two semiconductor materials with the cross-sectional area between the two being different to compensate for different thermoelectric material properties.

The Loring patent is also different from the present invention in regard to its employment of semiconductor materials as well as other features as will be more apparent hereinafter.

The patent to Thorp is also directed to semiconductor elements forming a thermocouple with a thermoelectric generator being formed of a plurality of stack pairs of layers of two different thermoelectric materials. The Thorp reference also shows the employment of semiconductor materials, which has been discussed above with regard to the patents to Fritts and Loring.

The patent to Gilbert is also directed to a thermopile formed of semiconductor materials joined together. Further, the Gilbert patent does illustrate the possible concept of the provision of a junction between the materials having a larger crosssectional area than either of the materials. Since the Gilbert patent illustrates the utilization of semiconductor materials, an important feature, of the present invention is missing from the Gilbert reference.

The patent to Dashevsky is generally related to thermocouples and thermopiles formed of semiconductor materials, and note is taken of the showing in Column 2, lines 21, et seq. of the statement that the intrinsic resistance or the thermoelement is affected by the width of the branch employed. Insofar as the Dashevsky patent illustrates the generally known concept of an inverse relationship between resistance and surface area, it can be considered relevant to the instant invention.

Patent No. 3,070,643, issued to Toulmin was the only patent discovered to be relevant to the new thermopile invention. The present invention relates to an entirely new construction for thermopiles. The new construction comprises a first material which is continuous and has repetitive segments with one portion extending between the regions of heat and cold and the other portion of the repeat segment extending from the cold to the hot region. A second material is joined to alternate repeat segments of the first material and the resulting thermopile assembly generates an electrical current under the influence of a temperature gradient.

In some aspects and as discussed below, the invention is similar to a thermocouple, but all thermocouples are formed with separate elements joined together, with neither of the elements comprising a continuous strip extending from repetitive thermocouple segment to thermocouple segment.

Insofar as the second material is electrically connected to only one portion of the first material extending between the source and sink, it is possible that the Thomson effect is operative. The Thomson effect is generally described in the aboveidentified patent to Toulmin, Column.1, lines 44-50, and this patent fails to show or suggest a structure similar to the applicant's novel current generator.

The Shaffer, 2,984,696 is related to energy storage. The Shaffer patent fails to show, suggest or disclose the provision or use of energy storage means, such as employing a latent heat of fusion technique, and therefore is inapplicable to the present invention.

An article appearing in the March 1977 issue of Consulting Engineer, Volume 48, No. 3, entitled "Designing and Citing Solar Power Plants" shows theuse of thermo-storage in connection with solar collectors. Since the specific arrangement illustrated and claimed in the present invention is neither shown, suggested nor disclosed in said publication, applicant's invention, as claimed, ispatentable over this publication.

Disclosure of Invention

In accordance with the principles of this invention, in one embodiment some of the objects are accomplished by providing a thermocouple formed oftwo conductors, with the conductors being joined in hot and cold regions. Each of the conductors has a generalized cross-sectional area, and the thermocouple comprises such conductors having a junction area significantly greater than the cross-sectional area of either of the elements. The use of large area junctions reduces the resistance in the thermocouple electrical path enabling an increase in current to be realized. Further, such large area junctions tend to minimize loss of junction heat by enlarging the area subjected to said heat.

In addition, this Invention provides a current generator to be located in a temperature gradient between a heat source region and a heat sink region, with the generator comprising a first continuous material having thermoelectric characteristics and having a first portion extending between the source and sink and a second portion extending between the sink and source, and a second material having thermoelectric characteristics electrically connected with only one of said first or second portions of the first material. By providing a continuous material, the ability to form a thermopile is efficiently achieved, since the second material may be joined or plated onto the first material on alternate repeat segments thereof. It is required that the second material be electrically connected to the first material, and this may be achieved by plating processes or any other process for efficiently and quickly adhering the second material to a portion of the first material. The conductivites of the materials, preferably are almost equal.

It should be noted that the Seebeck effect has been described above, but the operation of the present invention is not explainable only in accordance with this effect. It is possible that the Thomson effect also is in operation, but, to the present, the applicant Is unaware of any standard physical theory which can explain the functioning of this new thermocouple current generator structure, The storage system of this invention comprises a solar collector for receiving energy from the solar source, an absorber plate and heat storage means for absorbing the solar energy and storing this solar energy, the storage means comprising a latent heat storage medium, and locating said thermopiles in the region of said heat storage means to cause thermoelectric power to be generated. The provision of a latent heat storage medium in combination with the absorber plate for the solar collector in order to provide a temperature gradient sufficient to cause the thermopiles to generate thermoelectric power permits energy accumulation during the day for use at night, by controlling the temperature at which the medium changes from state to state.

Temperature rises during the day until the melting point of the medium is reached, and the heat input from the sun thereafter further melts the medium, without raising the temperature of the storage medium. At night, or when the sun is cloud covered, the heat storage again changes state, such as by freezing, releasing the heat absorbed to provide a source of heat for the thermopiles. Since the material chosen can have its latent heat fusion selected, while the material remains partially molten, the temperature remains constant and therefore, the voltage output of the thermoelectric generator or thermopiles also is constant.

Brief Description of Drawings

Fig. 1 is a perspective view of one embodiment of the present invention illustrating C-shape elements.

Fig. 2 is a cross-section taken through one of said C-shape elements.

Fig. 3 is a side view of the embodiment illustrated in Fig. 1.

Fig. 4 is a perspective view of another embodiment of the instant invention illustrating square zshape elements.

Fig. 5 is another embodiment of the invention illustrating square z-shape elements arranged in overlapping relationship.

Fig. 6 is a pictorial representation of the method of forming another embodiment of the instant invention. Fig. 7 is a top view of the thermopile formed in accordance with the method illustrated in Fig. 6.

Fig. 8 is a side view of an embodiment of the current generator of this invention. Fig. 9 is a perspective view of another embodiment of the current generator of this invention. Fig. 10 is an assembly view illustrating one method of forming the current generator of this invention.

Figs. 11 and 12 are embodiments of this invention formed in accordance with the method illustrated in Fig. 10.

Fig. 13 is another embodiment of the current generator of this invention.

Fig. 14 is a perspective view of one embodiment of the energy storage invention in which a latent heat storage medium is employed with a solar collector and thermopiles.

Fig. 15 Is an alternate embodiment, similar to Fig. 14, in which parabolic solar collectors are employed.

Fig. 16 is a schematic representative diagram illustrating another embodiment of the invention in which heat is stored in a region remotely located from a thermopile. Fig. 17 is another view similar to Fig. 16 in which the thermopiles and heat storage medium are remotely located from the absorber.

Fig. 18 is another embodiment similar to Figs. 16 and 17 in which the thermopiles are remotely located from the heat storage medium which itself is remotely located from the heat absorber.

Fig. 19 is another view similar to Fig. 18 in which parabolic collectors are utilized for receiving the solar energy. Best Mode for Carrying out the Invention

Turning now to the drawings, there is shown in Figure 1 an embodiment of the invention comprising a thermopile generally designated with the numeral 10 formed of an element 12 comprising a conductor of one material and another element 14 formed of a conductor of a same or dissimilar material, with the elements having a square C-shape.

Elements 12 and 14 comprise intermediate sections 16 and 18, respectively and upper leg portions 20 and 22 respectively, and lower leg portions 24 and 26 respectively. A generalized cross-sectional shape is generated along a plane 28 which is sub stantially perpendicular to the plane formed by the conductor elements, and the cross-sectional area 30 of the elements is illustrated in Fig. 2. The crosssectional area is generally rectangular and is approximately the same through the leg and Intermediate portions of the elements 12 and 14.

As illustrated in Figure 1, a thermopile is formed of successive pairs of reversely arranged square C-shape elements located between a heat source 32 and a heat sink 34. When the elements 12 and 14 are placed side-by-side a conducting spacer 36 is employed between respective legs of adjacent elements so as to make electrical connections at the thermoelectric junction. Thus, a thermoelectric junction is formed at the upper portion of the first element 12 which has its leg 20 in an electrical contact with leg 22 of element 14. As may be seen, the junction surface is the facing surfaces of legs 20 and 22, whose cross-sectional areas is significantly greater than the cross-sectional area of either the elements, as illustrated in Figure 2.

The arrangement of C-shape elements has advantageous features in that there is a minimum of heat transfer across the element, since intermediate section 16 is a thin connecting portion between legs 20 and 24. Such a thin intermediate portion minimizes heat flow between the heat source 32 and heat sink 34, so as to maximize temperature differences between the thermoelectric junctions, in order to increase the voltage developed therebetween.

Referring to Figure 3, there is shown a thermopile formed of repetitive pairs of oppositely¹ disposed squared C-shape elements. Referring to Figure 1, the current flows through leg 24, up intermediate sections 16, through leg 20, across the junction between legs 20 and 22, down intermediate section 18, into leg 26 across the junction between leg 26 and the leg of the next C-shape element 38, along the bottom leg of C-shape element 38 and upwardly through its intermediate portion to the next junction, which Is at the next upper leg. In this fashion, the current flows alternatively upwardly and downwardly through the C-shape elements with a number of thermocouples forming the thermopile. Figure 4 illustrate another embodiment of the instant invention in which squared z-shape elements are employed with the junction being formed between the facing surfaces of reversely disposed squared z-shape elements. In particular, the thermoelectric current will flow as indicated by the arrow through the bottom leg of first element 40 upwardly through the intermediate section across the junction between the first element 40 and second element 42, downwardly through the intermediate section of element 42, across the junction between element 42 and the next element 44 and upwardly through the intermediate section of element 44. The thermopile is formed of a number of such elements, with the heat-source 46being located at one junction area while the heat sink 48 is located at the opposite junction area. The difference in voltage formed at the junctions due to the thermoelectric differences enables the current to flow through the sequence of joined thermoelectric elements to form the thermocouple and thermopile of the instant invention. The area of the thermocouple junction is the facing surface of the adjoining elements which is relatively large in comparison to the cross-sectional area of any of the elements.

Figure 5 illustrates yet another embodiment of this invention where the thermocouple and thermopile is formed of overlapped squared z-shape elements 50 and 52. A heat source 54 is located at the upper junctions while heat sink 56 is located in the lower junctions. Thermoelectric current flows through the thermopile as indicated by the arrow. Such thermoelectric current crosses the junction between the matching respective legs of elements 50 and 52 and then vertically through the respective intermediate portions of the elements 52, then along the need for separate conductors to be integrated in the thermocouples.

Materials which may serve as elements in the thermocouple of this invention are generally identified as being electrical conductors. Materials such as nickel, nickel alloys, iron, iron alloys, and iron alloys with silicon, especially ductile iron may all be employed. Additionally, copper may be employed as well as copper alloys.

The individual elements illustrated in the prior figures may be easily formed by conventional metal forming techniques. The specific C and Z shapes employed are not intended to be limiting but are merely illustrative of conductor elements employed in the thermocouple with the junction between adjacent thermocouple elements being formed of the elements themselves because, of their electrical current carrying characteristics. These shapes also provide for large junction areas and narrow inter mediate sections

As another aspect of this invention, the relative surface areas may be arranged to be sized in relation to the resistivity of the materials in order to minimize impedance differences at the junctions.

Figures 6 and 7 illustrate one method of forming large numbers of thermocouples, with a series of triangular thermocouples being produced. Referring to Figure 6, a plurality of first conductors 60 are laid in parallel relationship to each other and on a slant and a plurality of second conductors 62 are laid crosswise across first conductors 60 with intersections formed therebetween as at 64. A grid is formed of elements 60 and 62 so interlaced and a cutting operation is performed along lines 66 after the materials 60 and 62 have been joined at their intersections. The resulting thermocouple is illustrated in Figure 7 and the junction 68 between elements 60 and 62 is formed of the overlapping portions of the elements joined at their intersections. The thermocouple and thermopile formed in accordance with Figures 6 and 7 is then placed between heat source 70 and heat sink 72, so that the junctions are located in the respective heat source and heat sink regions to generate an electric current through the thermopile. As may further be seen, the thermocouple formed in accordance with Figure 7 comprises conductors joined in regions of relative heat and cold with the area of the junction 68 being substantially larger than the cross-sectional area taken through a plane perpendicular to the conductors, since conductors 60 and 62 are thin strips of metal.

Although this invention has been described with solar energy being the source of heat, it is understood that the novel thermopile of this invention may be used with any source of heat. For instance, the invention may recapture energy usually disposed of such as heat escaping from a building during the winter. Other sources of heat may be employed.

Figure 8 illustrates an embodiment of the current generator invention in which a first continuous material 10' is formed of a thermoelectric material constructed to extend between a region of heat 12' and a region of cold 14'. The material 10' is formed into a repetitive series of similar patterns, with a first Intermediate portion 16' extending from the region of sink to source and the second intermediate portion 18' extending between source and sink. The first material has top portion 20' formed as well as base portion 22', with the top and base portions lying within the regions of relative heat and cold.

A second material 24' having thermoelectric characteristics is electrically connected to intermediate portion 16 and extends between the sink and source 14' the number of joining operations encountered in the prior art.

As an example, a standard thermopile with 10 thermocouples requires 20 separate elements, 10 of material 200 and 10 of material 202. Nineteen joining operations are required to construct said thermopile. In accordance with the invention, the present thermopile requires only a single piece of continuous material 200, to which 10 pieces of material 202 are joined by simple joining operations.

By employing a continuous strip for one of the two materials, -a rigid base for the assembly of the thermopile may be achieved, and enables such techniques as electroplating to be employed to connect the second material to the first.

Fig. 10 illustrates yet another technique for joining the discrete material 30' to the continuous material 32', by merely folding material 30' about material 32' to achieve the desired electrical connection between these two materials. Figures 11 and 12 illustrate two other embodiments of the current generator in accordance with this invention, with the current generator 40' of Fig. 11 being folded into the step-wave shape after a joining operation, such as the operation illustrated in Fig. 10. Figure 12 illustrates a current generator folded into a triangular form, with the second material joined to the first continuous material along only one leg of each triangular repeat segment 50'. The embodiment illustrated in Fig. 12 is formed after the second material is connected to the first material. Fig. 13 is a side view of yet another embodiment of this invention in which the first material is formed as a continuous step-wave 60' while the second material comprises discrete squared z-shape segments electrically connected, by way of plating or otherwise, to corresponding repetitive segments of continuous piece 60'. In accordance with the principles of this current generator invention, the continuous material may be a conductor or semiconductor, and the discrete material may also be a conductor or semiconductor, and any combination of conductors or semiconductors joined together by way of plating, gluing, or other techniques may be employed. It is important that the second material be electrically joined to the first material between the regions of hot and cold, and the joining techniques could be such so that there is discontinuous electrical contact or continuous electrical contact between these regions.

Referring now to Fig. 14, a source of light such as solar light irradiates from direction 10" toward a transparent cover 12" , which is formed of a double wall transparent construction, and the light passes through said transparent cover 12" to impinge upon an absorber plate 14". The absorber plate absorbs the solar energy and is integrally formed with a heat storage medium and 'means 16". A plurality of thermopiles 18" are connected below and to the heat storage medium 16", and thermal insulation 20" is provided in the upper region of thermopiles 18" in the area of the heat storage medium. A bottom radiator plate 22" is provided to cool the bottom portion of the thermopiles which are remotely located from the heat storage medium 16".

The invention will be briefly described in further detail with regard to Fig. 14, while the other embodiments will be described hereafter.

The transparent cover 12" may be formed of a double cover for purposes of heat insulation, and is capable of passing sunlight therethrough to irradiate on the absorber plate 14". The absorber plate has the heat storage means and medium 16" integrally formed therewith, and one possible arrangement being to provide a double plate for absorber plate 14" having a heat storage medium such as lithium nitrite, stannous chloride or aluminum iodide filled therein. During the day, the temperature will rise until the melting point of the materials stored within the heat storage means 16" reaches its melting point, and the heat input from the sun thereafter would further melt the heat storage material, without raising the temperature thereof. When the source of solar light terminates, the heat storage medium state changes, and in this case, would freeze, and heat would be released at a constant temperature as the material continues to change from its molten to the solid state .

In order to further insulate and retain the heat stored in medium 16", thermal insulation 20" is tightly packed against the bottom of the heat storage means 16" to hold the heat therewithin as efficiently as possible. Interspersed between the heat insulation means 20" are thermopiles 18", which have a general vertical orientation. The thermopiles are arranged so that the top portion is in the proximity of the heat storage means, while the bottom portion is in the proximity of the radiator plate 22".

In operation, thermopiles provide thermoelectric power related to the temperature gradient between the upper and lower portions thereof, and with the present invention, the upper temperature is maintained fairly constant over a large period of time. The period of time will be greater than that during which the sun is shining, and is related to the material used as the heat storage medium as well as the other construction features for ensuring temperature gradient across the thermopiles and retaining heat in the heat storage means 16". The above-described chemicals have a general latent heat of fusion at approximately 150°, and under conventional collection proceedings, normal irradiated sun passing through the transparent cover absorber plate and heat storage medium will easily reach that level.

As a matter of design choice and overall efficiency, maximum power output would be less than peak power obtainable under maximum sun conditions, such as at high noon. To provide for peak power demand greater than that supplied by the heat storage device, a supplemental battery system can be provided which would store electricity when the demand is below peak. This battery system need only store enough energy for several hours of maximum demand, and the system does not have to accommodate to fluctuating voltages from a solar collector, since the voltage output from the solar collector system illustrated in Fig. 14 is constant in view of the constant temperature achieved through use of a latent heat of fusion material forming the heat storage medium. Fig. 15 is a perspective view of another embodiment of my invention in which parabolic collectors 24" are employed to collect the solar energy. In view of the parabolic shape of these collectors, which replaces the transparent cover of the embodi ment of Fig. 1, absorbers 26" have a different configuration and sit within the base of the parabolic collectors to absorb the heat collected by collectors 24". In other respects, the embodiment of Fig. 2 is similar to Fig. 1 with a storage means 16" being provided having a storage medium for changing its state to store the heat through the latent heat of fusion principle described above. Further, there is provided thermal insulation 20", thermopiles 18" and a bottom radiator plate 22" which are arranged in the same manner and accomplish the same function as described above with regard to Fig. 14. The parabolic collectors enable the temperature to which the absorber plate can be heated to be increased over that achievable with the flat absorber plates and as a consequence, an increase In stored energy is achievable with said parabolic collectors.

The embodiments illustrated in Figsj.14 and 15 represent a compact thermoelectric generator system. Energy may also be stored, as is currently done for solar heating and cooling systems, in a tank located away from the absorber plate. This is a more complicated system, but has the advantage that a separate tank may be better insulated. Heat transfer from the collector to the tank may be effected by a fluid heat transfer medium, by heat pipes or by the storage material itself. In this case, it may be advantageous to store heat in the transition from liquid to gas of a substance with a suitable boiling point. The thermopiles could be attached to the solar absorber, and the flow of heat to and from the storage tank can be adjusted, as appropriate. Figures 3 through 6 illustrate such systems.

Referring now to Fig. 16, there is shown a source of light 30" irradiating upon an absorber plate 32" below which are connected thermopiles 34" . A conduit 36" is provided connected between absorber 32" and a remote storage tank 38". The storage medium, as described above, may be chosen to be a material which stores heat in the transition from liquid to gas, and the gaseous materials carried In conduits 36" between absorber plate 32" and storage tank 38". A valve 40" is provided between the absorber plate 32" and storage tank 38" to allow the storage material to pass from the absorber plate to the storage tank when the gaseous state has been reached. The storage tank may be provided with an outer thermal insulation covering 42" surrounding a heat storage medium 44" within which there is located a heat exchanger 46". The heat storage medium 44" changes from its liquid to gaseous state in accordance with the temperature to which the absorber plates is subjected, and valve 40' enables the remotely located heat storage medium to flow between thermopiles 34" and the storage tank 38", as appropriate for the generation of thermoelectric power from the thermopiles. The thermopiles may be arranged to have a suitable radiator plate (not shown) as appropriate.

Referring now to Fig. 17, there is shown yet another embodiment of a remotely located storage tank 38" in which a source of light 30" irradiates upon an absorber plate 32". In the embodiment of Fig. 17, valve 40" (see Fig. 16) is dispensed with, and a conduit 36" is provided between absorber plate 32" and storage tank 38". The heat storage tank 38" is surrounded by a thermal insulation 42" , and an additional thermal insulation 48" is provided on the bottom of absorber 32". The heat exchanger 46" is located within storage tank 38", and in this embodiment, thermopiles 34" are located in the region of the storage tank 38". This arrangement may be suitable where a large construction facility is employed in which the thermopiles are remotely located from the absorber plate. Although the efficiency is somewhat reduced, the size of the thermopiles and storage tank may be significantly larger than that achievable with the more compact unit of Figs. 14 and 16, so that longer term storage of power may be provided.

Fig. 18 is yet another embodiment of a remotely located storage tank 38'" having a source of light 30'" impinging upon an absorber plate 32"'. Insulation 48"' is located beneath absorber plate 32", and conduit 36'". carries the storage medium or heat transfer material from absorber plate 32"' to storage tank 38"'. Located within storage tank 38"' is a heat exchanger 46"' in which the heat storage medium is located as well as an outer thermal insulation 42"'. A valve 40"' allows further heat transfer medium to flow between the storage tank and the remotely located thermopiles 34"'. This arrangement as shown in Fig. 18 is similar to that of Fig. 17 in which the heat may be stored remotely from the collectors. The further embodiment of Fig. 18 allows for the generation of electricity by thermopiles 34"' at any time desired merely by operating valve 40"'. Thus, there is complete autonomy in the operation of the energy system illustrated in Fig. 18. Fig. 19 is yet another embodiment of my invention, which is similar to Fig. 18, but concentrating collectors 50" are substituted for the flat plate collectors found in the embodiments illustrated in Figs. 16 through 18. In all respects, the apparatus of Fig. 19 operates similarly to Fig. 18.

As illustrated above, my invention serves to accomplish four key functions, which are not found in the prior art.

My invention permits energy accumulation during the day and utilization of the energy during the day and at night. Depending upon the quantity of heat storage medium selected, and upon the temperature at which the latent heated fusion comes into operation, the energy storage can be for long periods of time. Further, peak power demands may be met by the provision of relatively efficient and small battery sytems, and in view of the constant voltage output provided by my invention., such storage batteries may be efficiently charged.

Since the temperature remains constant in view of the latent heat of fusion techniques, voltage regulation is provided without recourse to complicated electronics circuitry. Voltage will remain constant as long as the temperature does, and since maximum current depends upon the internal resistance, maximum power generation may also be constant.

Although the peak efficienty of the solar converter is higher without latent heat storage, since the maximum temperature is higher, the average efficiency over a twenty-four period is increased significantly by the use of latent heat storage, since it keeps the convertor working at a fairly high efficiency for a much longer period of time. Latent heat storage in the collector plate also serves to regulate the temperature in the region of the collector, and prevent the temperature from rising above design limits to damage the collector.

Provision of energy upon demand, as with the valve arrangement in Figs. 16, 18 and 19 represents a significant improvement .over the art, and further enables large scale thermoelectric generators to be provided.

Claims

1. A thermocouple comprising two materials joined in regions of relative heat and cold , each of said materials comprising an electrical conductor, each of said conductors having a general cross-sectional area taken along a plane substantially perpendicular to the plane formed by the conductor, said conductors being electrically joined together at mating surfaces thereof with the junction area of the mating surfaces between the conductors being greater than the cross-sectional area of either of the conductors.

2. The thermocouple as claimed in Claim 1, wherein each of the mating surface is planar.

3. The thermocouple as claimed in Claim 1, wherein each of said conductors comprises leg members separated by an intermediate section, said junction between said conductors comprising respective pairs of said leg members joined together.

4. The thermocouple as claimed in Claim 3, wherein each of said conductors comprises a squared C-shape member, with the junction between said conductors formed by electrically joining contiguously located leg portions of respective conductors.

5. The thermocouple as claimed in Claim 4, wherein the cross-sectional area of each of said squared C-shaped members is substantially rectangular in shape, with said conductors being placed in sideby-side orientation, further comprising electrically conducting spacer means being placed between the respective side surfaces of the leg portions for forming said electrical junction.

The thermocouple as claimed in Claim 1, wherein said conductors are arranged to be side-by-side with said junction formed by adjoining surfaces contacting each other.

7. The thermocouple as claimed in Claim 3, wherein each of said conductors comprises a squared Z- shape and said junction is formed by placing said conductors in face-to-face contact such that the side surface of the leg of one conductor touches the side surface of the leg of another conductor.

The thermocouple as claimed in Claim 3, wherein each of said conductors comprises a squared Z- shape and said junction is formed by touching the upper surface of one leg of said conductor to the bottom surface of one leg of the other conductor, such that said mating surface is formed by the overlapping upper and lower surface portions of the mating leg segments of the conductors.

9. The thermocouple as claimed in Claim 1, wherein said conductors are formed of metal strips connected to form a triangular shape with the vertex of the triangle formed by the overlapping of said elements forming said junction.

10. The thermocouple as claimed in Claim 1, wherein each of said conductors is formed of a different metal.

11. The thermocouple as claimed in Claim 10, wherein one of said conductors comprises an iron metal and the other comprises an iron alloy.

12. The thermopile comprising a plurality of thermocouples each comprising pairs of electrical conductors joined in regions of relative heat and cold, each of said conductors having a general cross-sectional area taken along a plane substantially perpendicular to the plane formed by the conductor, said pairs of conductors being electrically joined together at mating surfaces with the junction area of the mating surfaces between the conductors being greater than the crosssectional areas of the conductors.

13. A current generator for solar energy located in a temperature gradient between a heat source region and a heat sink region, said generator comprising a first continuous material having thermoelectric characteristics and having a first portion extending between said source and sink and a second portion extending between said sink and source, and a second material having thermoelectric characteristics electrically connected with only one of said first or second portions of said first material, said first and second materials being of substantially equal conductivity.

14. A current generator as claimed in Claim 13, wherein said second material comprises a different composition from said first material.

15. A current generator as claimed in Claim 13, wherein said second material is in physical contact with said first material, said physical contact forming said electrical connection with said first material,

16. A current generator as claimed in Claim 15, wherein said second material is plated onto said first material.

17. A current generator as claimed in Claim 15 , wherein said second material is in continuous electrical contact with said first material.

18. A current generator as claimed in Claim 13, wherein said first continuous material comprises a single square wave-shape comprising a base portion located in the sink region and a top portion in the source region and two step portions connected between said top and base, said second material being in continuous contact with said first material along one of said two step portions.

19. A current generator as claimed in Claim 18, wherein said second material is plated to said first material.

20. A current generator as claimed in Claim 18, wherein said second material is folded about said first material such that a sandwich of said first and second material is formed at said one step portion.

21. A current generator as claimed in Claim 13, wherein said first continuous material comprises a triangular shape formed of two legs with the top of said triangular shape formed by said two legs being in the source region and the base being in the sink region, said second material being in continuous contact with said first material along one of said legs.

22. A current generator as claimed in Claim 21, wherein said second material is plated to said first material.

23. A current generator as claimed in Claim 13, wherein said first and second materials are conductors.

24. A current generator as claimed in Claim 13, wherein said first and second materials are semi-conductors.

25. A current generator for solar energy located in a temperature gradient between a heat source region and a heat sink region, said generator comprising an electrically continuous material having repeat segments with each of said segments having one portion extending from said source to sink regions and at least a second portion extending from said sink to source regions, and a second electrically conductive material electrically connected with at repeat portions of said repeat segments of said first material, said first and second materials being of substantially equal conductivity.

26. A current generator as claimed in Claim 25, wherein said second material comprises a different composition from said first material.

27. A current generator as claimed in Claim 25, wherein said second material is in physical contact with said first material, said physical contact forming said electrical connection with said first material.

28. A current generator as claimed in Claim 27, wherein said second material is plated onto said first material.

29. A current generator as claimed in Claim 27, wherein said second material is in continuous electrical contact with said first material.

30. A current generator as claimed in Claim 25, wherein said first continuous material comprises a single square wave shape comprising a base located in the sink region and a top in the source region and two step portions connected between said top and base, said second material being in continuous contact with said first material along one of said two step portions.

31. A current generator as claimed in Claim 30, wherein said second material is plated to said first material.

32. A current generator as claimed in Claim 30, wherein said second material is folded about said first material such that a sandwich of said first and second material is formed at said one intermediate connecting, portion.

33. A current generator as claimed in Claim 25, wherein said first continuous material comprises a triangular shape formed of two legs with the top of said triangular shape formed by said two legs being in the source region and the base being in the sink region, said second material being in continuous contact with said first material along one of said legs.

34. A current generator as claimed in Claim 33, wherein said second material is plated to said first material.

35. A thermoelectric generator comprising a thermopile having one end to be placed in a hot region and the other end in a cold region, for the generation of electricity, means for generating regions of relative heat arid cold comprising solar collector means for receiving power from a solar source, absorber plate means connected with said solar collector means to absorb the heat of the sun impinging on said solar collector means,heat storage means for storing the heat absorbed in said absorber plate, said heat storage means comprising a storage material having a latent heat of fusion, said storage material changing its state under the influence of temperatures reached when said absorber receives said heat, said heat storage means conveying its stored heat to said thermopiles to cause electric power to be generated.

36. A thermoelectric generator as claimed in Claim 35, further comprising a radiator means connected with said thermopiles in said cold region to enhance the temperature gradient across said thermopile.

37. A thermoelectric generator as claimed in Claim 36, further comprising a transparent cover located between the solar source and said absorber plate said transparent cover comprising a double walled plate.

38. A thermoelectric generator as claimed in Claim 36, further comprising insulation means located beneath said heat storage means and held in contact therewith, said solar source being located above said heat storage means.

39. A thermoelectric generator as claimed in Claim 38, wherein said heat storage medium is integrally formed with said absorber plate, said absorber plate and storage medium comprising a sealed container located below said absorber plate, said sealed container holding said storage medium.

40. A thermoelectric generator as claimed in Claim

35, wherein said solar collector means comprises parabolic collectors.

41. A thermoelectric generator as claimed in Claim 35, wherein said heat storage means is remotely located from said solar collector means and said absorber plate means, further comprising heat exchange fluid for transferring the heat from said absorber plate to said heat storage means, and conduit means connected between said heat storage means and said absorber plate means for carrying said fluid.

42. A thermoelectric generator as claimed in Claim 41, further comprising valve means located in said conduit to control the time when the heat storage means supplies its stored heat to said thermopiles.

43. A thermoelectric generator as claimed in Claims 35 or 42, wherein said thermopiles are connected with said absorber plate means.

44. A thermoelectric generator as claimed in Claim 41, wherein said thermopiles are connected to said heat storage means.

45. A thermoelectric generator as claimed in Claim 41, further comprising second conduit means connected between said heat storage means and thermopiles, said thermopiles being remotely located with respect to said heat storage means, and heat exchange fluid located in said second conduit means, said second conduit comprising second valve means for controlling the flow of heat from said heat storage means to said thermopiles.

46. A thermoelectric generator as claimed in Claims 41 or 45, wherein said heat exchange fluid is formed of said storage material having said latent heat of fusion.