Systems and methods of thermal energy storage

Abstract

Systems and methods of energy storage and release comprise at least one storage vessel and a combined conveyor and heat transfer device linked to the at least one storage vessel by at least one discharge device. The combined conveyor and heat transfer device includes a rotatable conveyor drum and at least one heat transfer fluid conduit within the rotatable conveyor drum. A granular material travels from the at least one storage vessel to the combined conveyor and heat transfer device via the at least one discharge device, and the rotatable conveyor drum moves the granular material therethrough in counterflow to a flow of heat transfer fluid traveling through the heat transfer fluid conduit.

1 . A system of energy storage and release, comprising:
 at least one storage vessel;   a combined conveyor and heat transfer device linked to the at least one storage vessel by at least one discharge device, the combined conveyor and heat transfer device including:
 a rotatable conveyor drum; and 
 at least one heat transfer fluid conduit within the rotatable conveyor drum; 
   wherein a granular material travels from the at least one storage vessel to the combined conveyor and heat transfer device via the at least one discharge device, and the rotatable conveyor drum moves the granular material therethrough in counterflow to a flow of heat transfer fluid traveling through the heat transfer fluid conduit.   
     
     
         2 . The system of  claim 1  wherein the granular material is sand. 
     
     
         3 . The system of  claim 1  wherein the rotatable conveyor drum is an Archimedes screw. 
     
     
         4 . The system of  claim 1  wherein the rotatable conveyor drum comprises one or more vanes fixed to an inner surface thereof. 
     
     
         5 . The system of  claim 1  wherein the at least one storage vessel has at least one angled wall. 
     
     
         6 . The system of  claim 1  wherein the at least one heat transfer fluid conduit comprises a plurality of fluid conduits arranged in a bundle. 
     
     
         7 . The system of  claim 1  wherein when the rotatable conveyor drum rotates the granular material pours over the at least one heat transfer fluid conduit such that heat exchange occurs between the granular material and the heat transfer fluid. 
     
     
         8 . The system of  claim 4  wherein the rotatable conveyor drum rotates such that the one or more vanes pick up and rain the granular material over the at least one heat transfer fluid conduit. 
     
     
         9 . The system of  claim 1  wherein the at least one storage vessel comprises a first and second storage vessel, the first storage vessel having a higher temperature than the second storage vessel. 
     
     
         10 . The system of  claim 1  wherein the stored energy is heat gathered by, or discharged to, a concentrating solar thermal power plant. 
     
     
         11 . The system of  claim 4  wherein the one or more vanes are one of: spiral shaped, longitudinally straight, substantially T-shaped and substantially V-shaped. 
     
     
         12 . A method of storing thermal energy, comprising:
 providing a granular material and a heat transfer fluid, the heat transfer fluid having a temperature relatively higher than a temperature of the granular material;   conveying the granular material and the heat transfer fluid such that the granular material pours over a tube carrying the heat transfer fluid such that heat exchange occurs between the granular material and the heat transfer fluid.   
     
     
         13 . The method of  claim 12  wherein the granular material travels in overall counterflow to a flow of heat transfer fluid. 
     
     
         14 . The method of  claim 12  wherein the granular material travels in overall cocurrent flow to a flow of heat transfer fluid. 
     
     
         15 . The method of  claim 12  wherein the granular material is sand. 
     
     
         16 . The method of  claim 12  further including releasing stored thermal energy, comprising:
 providing a granular material and a heat transfer fluid, the granular material having a temperature relatively higher than a temperature of the heat transfer fluid; 
 conveying the granular material and the heat transfer fluid such that the granular material pours over a tube carrying the heat transfer fluid such that heat exchange occurs between the granular material and the heat transfer fluid. 
 
     
     
         17 . A combined conveyor and heat transfer device, comprising:
 a rotatable conveyor drum; and   at least one heat transfer fluid conduit within the rotatable conveyor drum;   wherein the rotatable conveyor drum moves a granular material therethrough in counterflow to a flow of heat transfer fluid traveling through the heat transfer fluid conduit.   
     
     
         18 . The device of  claim 17  wherein the rotatable conveyor drum is an Archimedes screw. 
     
     
         19 . The device of  claim 17  wherein when the rotatable conveyor drum rotates the granular material pours over the at least one heat transfer fluid conduit such that heat exchange occurs between the granular material and the heat transfer fluid. 
     
     
         20 . The device of  claim 17  wherein the rotatable conveyor drum is capable of rotating at one or more speeds.