Method of and apparatus for thermal energy-to-electrical energy conversion using charge carrier excitation transfer through electrostatic coupling between hot and relatively cold juxtaposed surfaces separated by a small gap and using single carrier cold-side conversion

Abstract

An improved method of and apparatus for thermal-to-electric conversion involving relatively hot and cold juxtaposed surfaces separated by a small vacuum gap wherein the cold surface provides an array of single charge carrier converter elements along the surface and the hot surface transfers excitation energy to the opposing cold surface across the gap through Coulomb electrostatic coupling interaction.

1 . In a thermal-to-electric conversion apparatus, relatively hot and cold juxtaposed surfaces separated by a small vacuum or gas gap, the cold surface providing a chip array of single charge carrier converter elements, and the hot surface electrostatically transferring excitation energy to the opposing cold surface converter elements across the gap through Coulomb electrostatic coupling interaction. 
     
     
         2 . The conversion apparatus of  claim 1  wherein an electron from a first electron reservoir is introduced into a lower level excitation state of each of the converter elements on the cold surface, and then Coulomb-couples across the gap to a carrier charge on the hot surface, producing a quantum correlation therebetween that leads to excitation transfer from the hot surface to the cold surface that promotes said electron to a higher level excitation state. 
     
     
         3 . The conversion apparatus of  claim 2  wherein said excited higher level state electron thereupon tunnels to a second cold-surface electron reservoir maintained at an elevated potential relative to said first reservoir, and an electrical load is connected between the reservoirs and driven by the current caused by the promoted electron(s). 
     
     
         4 . The conversion apparatus of  claim 3  wherein only a single type carrier charge is promoted at a time. 
     
     
         5 . The conversion apparatus of  claim 4  wherein the single carrier charge is one of electrons or holes. 
     
     
         6 . The conversion apparatus of  claim 3  wherein the converter elements comprise an array of semi-conductor elements that are chip-integrated along the cold surface in a matrix substrate and interconnected by a network of electron reservoir conductors or buses within the chip substrate to provide the appropriate series and/or parallel connections amongst and between the elements of the array. 
     
     
         7 . The conversion apparatus of  claim 6  wherein the sets of said respective first and second electron reservoir conductors or buses in the array are commonly connected to opposite sides of said load. 
     
     
         8 . The conversion apparatus of  claim 6  wherein the semi-conductor elements are of InSb material and/or Ga 0.31 In 0.69 Sb material. 
     
     
         9 . The conversion apparatus of  claim 6  wherein the material of the hot surface is selected from the group consisting of flat metal, metallic copper, semi-metal, and highly doped semiconductor material. 
     
     
         10 . The conversion apparatus of  claim 6  wherein the election reservoir conductors or buses are of doped n-type InSb. 
     
     
         11 . The conversion apparatus of  claim 6  wherein the chip matrix substrate on the cold side is GaSb. 
     
     
         12 . The conversion apparatus of  claim 6  wherein the hot surface is about 1300K and the relatively cold surface is about 300K. 
     
     
         13 . The conversion apparatus of  claim 6  wherein the carrier converter elements are in the form of an array of one or more of semi-conductor dots or bars of varied geometry, semi-conductor short cylinders or wires, and small sheets providing quantum wells integrated within the chip substrate. 
     
     
         14 . The conversion apparatus of  claim 13  wherein the semi-conductor elements and the interconnecting conductors or buses are integrated in the substrate, with some oriented parallel to the cold surface, and some horizontally and/or vertically oriented. 
     
     
         15 . The conversion apparatus of  claim 13  wherein dimensions of the dots or bars are of the order of about 50 to 120 Å. 
     
     
         16 . A method of converting thermal to electric energy, that comprises, juxtaposing relatively cold-side conversion and relatively hot-side radiating surfaces separated by a small gap; providing lower state electrons on or near the cold surface; Coulomb-coupling the lower state electrons to the carrier charges on the hot surface; transferring heat from the hot-side surface through the coupling to said cold-side surface lower-state electrons to excite them to a higher state; collecting the higher state electrons at or near the cold surface to generate a higher potential; and extracting the resulting converted electric energy in response to said higher potential. 
     
     
         17 . The method of  claim 16  wherein the conversion cold-side surface comprises an array of interconnected converter elements each having respective quantum wells supporting the lower and higher electron states, and maintained at a ground potential. 
     
     
         18 . The method of  claim 17  wherein said collecting of the higher state electrons is effected by tunneling between such ground wells and higher potential wells on the cold side. 
     
     
         19 . The method of  claim 16  wherein the converter elements are caused to promote only a single type of carrier charge at a time. 
     
     
         20 . The method of  claim 19  wherein the single carrier type charge is one of electrons or holes.