Liquid-air transpired solar collectors

Abstract

The invention, in some embodiments, relates to solar energy collectors, and methods of use thereof. In some embodiments, the invention relates to liquid-air transpired solar energy collectors, and methods of use thereof. In some embodiments, the invention relates to thermal energy transfer systems that comprise solar energy collectors, and methods of use thereof. In some embodiments of the invention, methods of constructing solar energy collectors are provided.

What is claimed is: 
     
         1 . A solar energy collector comprising:
 a housing forming a cavity for containing a first fluid, the cavity having at least one outlet configured and arranged for allowing the first fluid to exit from the cavity;   a solar absorber comprising a plurality of openings, the solar absorber being configured and arranged for absorbing incident solar radiation, thereby acquiring thermal energy, and for allowing passage of the first fluid through each of the plurality of openings into the cavity such that thermal energy is transferred to the first fluid; and   at least one conduit extending through the cavity, the at least one conduit configured and arranged for allowing passage of a second fluid through the cavity such that the second fluid is fluidically isolated from the first fluid and such that thermal energy is transferred to the second fluid.   
     
     
         2 . The solar energy collector of  claim 1 , wherein the at least one conduit is attached to the solar absorber. 
     
     
         3 . The solar energy collector of  claim 1 , wherein the openings are circular holes. 
     
     
         4 . The solar energy collector of  claim 3 , wherein the circular holes have a diameter in a range of 1 mm to 10 mm. 
     
     
         5 . The solar energy collector of  claim 1  wherein the openings comprise louvers. 
     
     
         6 . The solar energy collector of  claim 1 , wherein the openings are arranged in a triangular or hexagonal pattern or square pattern. 
     
     
         7 . The solar energy collector of  claim 1 , wherein the pitch of the openings is in a range of 10 mm to 50 mm. 
     
     
         8 . The solar energy collector of  claim 1 , wherein the areal density of openings in the solar absorber is in a range of 400 to 40,000 openings/m 2 . 
     
     
         9 . The solar energy collector of any preceding claim, wherein the plurality of openings are configured and arranged such that the following relationship is satisfied: 
       
         
           
             
               
                 0.25 
                 < 
                 
                   
                     
                       ( 
                       
                         pitch 
                         
                           D 
                           h 
                         
                       
                       ) 
                     
                     
                       - 
                       1.21 
                     
                   
                    
                   
                     Re 
                     d 
                     0.43 
                   
                 
                 < 
                 1.039 
               
               , 
             
           
         
         wherein pitch is the average distance between the center of each opening, D h  is the diameter of each opening, and Re d  is a Reynolds number based on air flowing through the openings at an air flow velocity through each opening within a range of 0.001 m/s to 0.01 m/s. 
       
     
     
         10 . The solar energy collector of any preceding claim further comprising a first fluid flow device configured and arranged for moving a first fluid out of the cavity through the at least one outlet. 
     
     
         11 . The solar energy collector of  claim 10 , wherein the first fluid flow device is further configured and arranged for moving the first fluid through the plurality of openings into the cavity, and toward the at least one outlet. 
     
     
         12 . The solar energy collector of  claim 1 , wherein the cavity comprises at least one inlet, separate from the plurality of openings in the solar absorber, configured and arranged for allowing the first fluid to enter into cavity such that it combines with the first fluid entering into the cavity through the plurality of openings. 
     
     
         13 . The solar energy collector of  claim 12 . further comprising a first fluid flow device configured and arranged for moving the first fluid through the plurality of openings and the at least one inlet into the cavity, and moving the first fluid toward the at least one outlet. 
     
     
         14 . The solar energy collector of  claim 10 , wherein the first fluid flow device is a fan or pump. 
     
     
         15 . The solar energy collector of  claim 1 , wherein the first fluid is air. 
     
     
         16 . The solar energy collector of  claim 10 , wherein the first fluid flow device is configured and arranged for moving the first fluid through the at least one conduit at a thermal capacitance rate per unit area of the solar absorber surface that is exposed to solar radiation in a range of 1 W/m 2 -K to 100 W/m 2 -K. 
     
     
         17 . The solar energy collector of  claim 1  further comprising a second fluid flow device configured and arranged for moving the second fluid through the at least one conduit. 
     
     
         18 . The solar energy collector of  claim 17 , wherein the second fluid flow device is a pump. 
     
     
         19 . The solar energy collector of  claim 1 , wherein the second fluid is a liquid. 
     
     
         20 . The solar energy collector of  claim 19 , wherein the second fluid is water or an aqueous solution. 
     
     
         21 . The solar energy collector of  claim 17 , wherein the second fluid flow device is configured and arranged for moving the second fluid through the at least one conduit at a mass flow rate per cross-sectional area of the conduit of less than 0.02 kg/s-m 2 . 
     
     
         22 . The solar energy collector of  claim 17 , wherein the second fluid flow device is configured and arranged for moving the second fluid through the at least one conduit at a thermal capacitance rate per unit area of the solar absorber surface that is exposed to solar radiation in a range of 4 W/m 2 -K to 200 W/m 2 -K. 
     
     
         23 . The solar energy collector of  claim 1 , wherein the solar absorber is a plate having a length in a range of 1 m to 5 m and a width in a range of 1 m to 5 m. 
     
     
         24 . The solar energy collector of  claim 1 , wherein the absorber has an emissivity of at least 0.8. 
     
     
         25 . The solar energy collector of  claim 1 , wherein the cavity has a substantially rectangular cross-section. 
     
     
         26 . The solar energy collector of  claim 23 , wherein the substantially rectangular cross-section has a depth in a range of 0.025 m to 0.5 m. 
     
     
         27 . The solar energy collector of  claim 23 , wherein the substantially rectangular cross-section has a perimeter in a range of 1 m to 4 m. 
     
     
         28 . The solar energy collector of  claim 1  further comprising a support structure configured and arranged to position the absorber at a desired zenith angle. 
     
     
         29 . The solar energy collector of  claim 1  further comprising
 a first fluid flow device configured and arranged for moving the first fluid from within the cavity through the at least one outlet at a first fluid capacitance rate, {dot over (m)}c p     first fluid    and 
 a second fluid flow device configured and arranged for moving the second fluid through the at least one conduit, at a second fluid capacitance rate, {dot over (m)}c p     second fluid   , such that R {dot over (m)}cp  is between 0.4 and 0.7, 
 wherein {dot over (m)}c p     first fluid    is the product of the mass flow rate of the first fluid through the at least one outlet and the heat capacity of the first fluid, 
 wherein {dot over (m)}c p     second fluid    is the product of the mass flow rate of the second fluid through the at least one conduits and the heat capacity of the second fluid, and 
 wherein: 
 
       
         
           
             
               
                 R 
                 
                   
                     m 
                     . 
                   
                    
                   cp 
                 
               
                
               
                   
               
                
               is 
                
               
                   
               
                
               
                 
                   
                     
                       m 
                       . 
                     
                      
                     
                       c 
                       
                         p 
                         
                           first 
                            
                           
                               
                           
                            
                           fluid 
                         
                       
                     
                   
                   
                     
                       
                         m 
                         . 
                       
                        
                       
                         c 
                         
                           p 
                           
                             first 
                              
                             
                                 
                             
                              
                             fluid 
                           
                         
                       
                     
                     + 
                     
                       
                         m 
                         . 
                       
                        
                       
                         c 
                         
                           p 
                           
                             second 
                              
                             
                                 
                             
                              
                             fluid 
                           
                         
                       
                     
                   
                 
                 . 
               
             
           
         
       
     
     
         30 . A method of operating a solar energy collector, the method comprising:
 positioning a solar energy collector of  claim 1  in an appropriate environment such that solar radiation impinges on the solar absorber, thereby transferring thermal energy to the solar absorber;   causing a first fluid to move into the cavity through the plurality of openings in the solar absorber and out of the cavity through the at least one outlet, wherein thermal energy is transferred to the first fluid; and   causing a second fluid to move through the at least one fluid conduit, wherein thermal energy is transferred to the second fluid.   
     
     
         31 . The method of  claim 30 , wherein the first fluid is caused to move from within the cavity out through the at least one outlet at a first fluid capacitance rate, {dot over (m)}c p     first fluid   , and
 to the second fluid is caused to move through the at least one conduit at a second fluid capacitance rate, {dot over (m)}c p     second fluid   , such that R {dot over (m)}cp  is between 0.4 and 0.7,   wherein {dot over (m)}c p     first fluid    is the product of the mass flow rate of the first fluid through the at least one outlet and the heat capacity of the first fluid,   wherein {dot over (m)}c p     second fluid    is the product of the mass flow rate of the second fluid through the at least one conduits and the heat capacity of the second fluid, and   wherein:   
       
         
           
             
               
                 R 
                 
                   
                     m 
                     . 
                   
                    
                   cp 
                 
               
                
               
                   
               
                
               is 
                
               
                   
               
                
               
                 
                   
                     
                       m 
                       . 
                     
                      
                     
                       c 
                       
                         p 
                         
                           first 
                            
                           
                               
                           
                            
                           fluid 
                         
                       
                     
                   
                   
                     
                       
                         m 
                         . 
                       
                        
                       
                         c 
                         
                           p 
                           
                             first 
                              
                             
                                 
                             
                              
                             fluid 
                           
                         
                       
                     
                     + 
                     
                       
                         m 
                         . 
                       
                        
                       
                         c 
                         
                           p 
                           
                             second 
                              
                             
                                 
                             
                              
                             fluid 
                           
                         
                       
                     
                   
                 
                 . 
               
             
           
         
       
     
     
         32 . The method of  claim 30 , wherein the first fluid is air. 
     
     
         33 . The method of  claim 30 , wherein the second fluid is water or an aqueous solution. 
     
     
         34 . The method of  claim 30 , wherein the step of causing the first fluid to move through the housing from the at least one inlet to the at least one outlet, comprises operating the first fluid flow device. 
     
     
         35 . The method of  claim 34 , wherein the first fluid flow device is a fan or pump. 
     
     
         36 . The method of  claim 30 , wherein the step of causing the second fluid to move through the at least one fluid conduit, comprises operating the second fluid flow device. 
     
     
         37 . The method of  claim 34 , wherein the first fluid flow device is a pump. 
     
     
         38 . A system comprising:
 (a) a solar energy collector of  claim 1 ,
 wherein the solar energy collector comprises:
 (i) a first fluid flow device configured and arranged for moving a first fluid from within the cavity out through at least one fluid outlet, and 
 (ii) a second fluid flow device configured and arranged for moving a second fluid through the at least one conduit, and 
 
   (b) a liquid desiccant regeneration device,
 wherein the at least one fluid outlet and the at least one conduit are configured and arranged for supplying the first fluid and the second fluid to the liquid desiccant regeneration system. 
   
     
     
         39 . The system of  claim 38 , wherein the liquid desiccant regeneration (LDR) device is a spray cooled type LDR device, packed bed type LDR device or falling film type LDR device. 
     
     
         40 . The system of  claim 38 , wherein the at least one fluid outlet is configured and arranged for supplying the first fluid to provide thermal energy for heating of a desiccant, and the at least one conduit is configured and arranged for supplying the second fluid to provide thermal energy for regenerating the desiccant.