Methods and systems for thermal energy storage and recovery

Abstract

Thermal energy storage and recovery methods and systems are provided herein, which utilize a thermal energy storage vessel. The vessel comprises a packed bed of chemically inert particulates exhibiting high thermal conductivity. A gaseous heat transfer fluid (e.g., steam) is fed to the vessel, whereby at least a portion of the fluid condenses on the particulates and transfers latent heat to the particulates. During a heat recovery step, a heat recovery fluid (e.g., air) is fed to the vessel, whereby sensible heat transfers from the particulates to the heat recovery fluid. The warmed heat recovery fluid may then be used to provide required heat for a variety of applications.

1 . A method of storing thermal energy contained within a condensable fluid for later use comprising:
 feeding a gaseous heat transfer fluid into a vessel comprising a packed bed of inert particulates;   contacting said gaseous heat transfer fluid with said inert particulates and condensing at least a portion of said heat transfer fluid on said inert particulates, wherein said contacting and condensing step transfers at least a portion of the latent heat contained within said gaseous heat transfer fluid to said particulates; and   storing said portion of the latent heat within said particulates for a period of time until at least a portion of the stored latent heat can be recovered from said particulates.   
     
     
         2 . The method of  claim 1 , wherein said heat transfer fluid is steam. 
     
     
         3 . The method of  claim 2 , further comprising generating said steam using energy from a renewable steam generator. 
     
     
         4 . The method of  claim 1 , further comprising the step of recovering said portion of the stored latent heat from said particulates, said recovering step comprising:
 feeding a heat recovery fluid to said vessel;   contacting said heat recovery fluid with said inert particulates and transferring thermal energy from said particulates to said heat recovery fluid in the form of sensible heat, thereby forming a warmed heat recovery fluid.   
     
     
         5 . The method of  claim 4 , further comprising directing said warmed heat recovery fluid to a heat exchange unit. 
     
     
         6 . The method of  claim 5 , wherein said heat exchange unit comprises a component of an absorption refrigeration system. 
     
     
         7 . The method of  claim 5 , wherein said heat exchange unit comprises a component of an indoor heating system. 
     
     
         8 . The method of  claim 4 , wherein said heat recovery fluid is air. 
     
     
         9 . The method of  claim 4 , wherein said recovering step occurs over a greater period of time than said contacting and condensing step. 
     
     
         10 . A thermal energy storage system comprising:
 an evaporator adapted for vaporizing a fluid stream;   a vessel comprising at least one packed bed of inert particulates and having at least one fluid inlet and at least one fluid outlet; and   a conduit configured to direct the vaporized fluid stream from the evaporator to said at least one fluid inlet,   said at least one fluid outlet configured to remove a condensate of the vaporized fluid stream from said vessel.   
     
     
         11 . The system of  claim 10 , wherein said evaporator is a steam generator. 
     
     
         12 . The system of  claim 11 , wherein said steam generator is a renewable steam generator. 
     
     
         13 . The system of  claim 10 , wherein said vaporized fluid stream comprises steam. 
     
     
         14 . The system of  claim 10 , further comprising:
 a heat exchange unit; and   a second conduit configured to direct a heat recovery fluid from said one or more fluid outlets to said heat exchange unit.   
     
     
         15 . The system of  claim 14 , wherein said heat recovery fluid is air. 
     
     
         16 . The system of  claim 14 , wherein said heat exchange unit comprises a component of an absorption refrigeration system. 
     
     
         17 . The system of  claim 14 , wherein said heat exchange unit comprises a component of an indoor heating system. 
     
     
         18 . The system of  claim 10 , wherein said at least one packed bed of inert particulates comprises a cylindrical chamber and a plurality of solid, spherical particles having an average diameter of less than 3 millimeters. 
     
     
         19 . The system of  claim 18 , wherein said particles have an average diameter of from about 1 mm to 3 mm. 
     
     
         20 . The system of  claim 10 , wherein said particulates comprise at least one of alumina, graphite, silica, quartz, ceramic, or rock.