System and process for using solar radiation to produce electricity

Abstract

A system for capturing solar radiation at a variable rate and providing heat at a constant rate to an electrical generating station is described. The system uses a thermal storage component that includes two or more thermal storage zones to coordinate the rate and quantity of heat delivered to the generating station.

1 . A system for using solar radiation to produce electricity, comprising:
 (a) a solar collector that receives solar radiation at a variable rate, measured as joules per hour, and uses said radiation to heat a thermal transfer fluid;   (b) a thermal storage component connected to said collector, said thermal storage component comprising at least a first thermal storage zone and a second thermal storage zone, said storage zones comprise ceramic packing elements, wherein said first zone's heat transfer coefficient per unit volume exceeds said second zone's heat transfer coefficient per unit volume by at least 10 percent; and   to (c) an electrical generating station connected to said thermal storage component, wherein said thermal transfer fluid transfers heat at a constant rate, measured as joules per hour, and a constant temperature to said generating station.   
     
     
         2 . The system of  claim 1  wherein said first zone's specific heat capacity exceeds said second zone's specific heat capacity by at least 10 percent. 
     
     
         3 . The system of  claim 1  wherein the geometric surface area per unit volume of said first zone's packing elements exceeds said the geometric surface area per unit volume of second zone's packing elements by at least 10 percent. 
     
     
         4 . The system of  claim 1  wherein said first zone's mass per unit volume exceeds said second zone's mass per unit volume by at least 10 percent. 
     
     
         5 . The system of  claim 1  wherein said generating station houses an expandable fluid that reversibly converts from a liquid to a gas in response to increases and decreases in the temperature of the expandable fluid, and wherein said transfer of heat to said generating station expands the volume of the expandable fluid which drives said generator. 
     
     
         6 . The system of  claim 3  wherein said first storage zone's geometric surface area per unit volume exceeds said second zone's geometric surface area per unit volume by at least 15 percent. 
     
     
         7 . The system of  claim 1  wherein said zones comprise randomly oriented packing elements. 
     
     
         8 . The system of  claim 1  wherein said system further comprises a supplemental source of heat. 
     
     
         9 . The system of  claim 1  wherein said system further comprises a thermal equilibration tank. 
     
     
         10 . A system for using solar radiation to produce electricity, comprising:
 (a) a solar collector that receives solar radiation at a variable rate, measured as joules per hour, and uses said radiation to heat a thermal transfer fluid;   (b) a thermal storage component connected to said collector, said thermal storage component comprising at least a first thermal storage zone and a second thermal storage zone, said storage zones comprise ceramic packing elements wherein the individual thermal conductivity of said first zone's packing elements exceeds the individual thermal conductivity of said second zone's packing elements by at least 10 percent; and   (c) an electrical generating station connected to said thermal storage component, wherein said thermal transfer fluid transfers heat at a constant rate, measured as joules per hour, and a constant temperature to said generating station.   
     
     
         11 . The system of  claim 10  wherein the individual mass of said first zone's packing elements exceeds the individual mass of said second zone's packing elements by at least 10 percent. 
     
     
         12 . The system of  claim 10  wherein the individual heat capacity of said first zone's packing elements exceeds the individual heat capacity of said second zone's packing elements by at least 10 percent. 
     
     
         13 . An apparatus, for receiving solar radiation at a variable rate and dispensing heat at a constant rate, comprising: at least a first thermal storage zone and a second thermal storage zone, said storage zones comprise ceramic packing elements, wherein said first zone's heat transfer coefficient per unit volume exceeds said second zone's heat transfer coefficient per unit volume by at least 10 percent. 
     
     
         14 . The apparatus of  claim 13  wherein said first zone's specific heat capacity exceeds said second zone's specific heat capacity by at least 10 percent. 
     
     
         15 . The apparatus of  claim 13  wherein the geometric surface area per unit volume of said first zone's packing elements exceeds the geometric surface area per unit volume of second zone's packing elements by at least 10 percent. 
     
     
         16 . The apparatus of  claim 13  wherein said first zone's mass per unit volume exceeds said second zone's mass per unit volume by at least 10 percent. 
     
     
         17 . The apparatus of  claim 15  wherein the geometric surface area per unit volume of said first zone's packing elements exceeds the geometric surface area per unit volume of second zone's packing elements by at least 15 percent. 
     
     
         18 . The apparatus of  claim 14  wherein said first zone's specific heat capacity exceeds said second zone's specific heat capacity by at least 15 percent. 
     
     
         19 . The apparatus of  claim 13  further comprising a thermal transfer fluid disposed within said storage zones. 
     
     
         20 . The apparatus of  claim 13  wherein said first thermal storage zone comprises a plurality of pipes having the same inside diameter, each pipe comprising ceramic media disposed therein. 
     
     
         21 . The apparatus of  claim 13  wherein said first thermal storage zone comprises at least a first pipe having a length to width ratio of at least 5:1, said first pipe comprising packing elements disposed therein, said apparatus further comprising a fluid distribution system connected to said pipe and a fluid collection system connected to said first pipe. 
     
     
         22 . The apparatus of  claim 13  wherein said zones comprise randomly oriented ceramic packing elements. 
     
     
         23 . The apparatus of  claim 21  wherein said second thermal storage zone comprises a second pipe having a length to width ratio of at least 5:1, said second pipe comprising packing elements disposed therein, wherein the diameter of said second pipe is at least ten percent larger than the diameter said first pipe, said second pipe connected to said fluid distribution system and said fluid collection system. 
     
     
         24 . The apparatus of  claim 23  further comprising a third zone comprising a third pipe having a length to width ratio of at least 5:1, said third pipe comprising packing elements disposed therein, wherein the diameter of said third pipe is at least ten percent larger than the diameter said second pipe, said third pipe connected to said fluid distribution system and said fluid collection system. 
     
     
         25 . The apparatus of  claim 21  further comprising a heat transfer fluid disposed within said first pipe and in contact with said packing elements. 
     
     
         26 . An apparatus, for receiving solar radiation at a variable rate and dispensing heat at a constant rate, comprising: at least a first thermal storage zone and a second thermal storage zone, said storage zones comprise ceramic packing elements, wherein the individual thermal conductivity of said first zone's packing elements exceeds the individual thermal conductivity of said second zone's packing elements by at least 10 percent. 
     
     
         27 . The apparatus of  claim 26  wherein the individual heat capacity of said first zone's packing elements exceeds the individual heat capacity of said second zone's packing elements by at least 10 percent. 
     
     
         28 . The apparatus of  claim 26  wherein the individual mass of said first zone's packing elements exceeds the individual mass of said second zone's packing elements by at least 10 percent. 
     
     
         29 . A process, for using solar radiation to produce electricity, comprising:
 (a) receiving solar radiation at a variable rate and converting said radiation to heat;   (b) within a twenty-four hour period, storing at least twenty-five percent of said heat in a thermal storage component comprising a first storage zone and a second storage zone; and   (c) transferring said heat at a constant rate, measured as joules per hour, and a constant temperature to an electrical generating station.   
     
     
         30 . The process of  claim 29  wherein, within a 24 hour period, step (a) comprises receiving said solar radiation for at least 2 hours and no more than 18 hours. 
     
     
         31 . The process of  claim 29  wherein step (c) comprises transferring said heat solely from said first thermal storage zone and then solely from said second thermal storage zone. 
     
     
         32 . The process of  claim 29  wherein step (c) comprises transferring said heat simultaneously from said first thermal storage zone and said second thermal storage zone.