Abstract:
A solar energy collection conduit ( 10 ) comprising an optical concentrator ( 40 ) incorporated into an outer tube ( 30 ) having a sunlight-transmitting ceiling ( 32 ). The concentrator ( 40 ) focuses, guides, directs, and/or otherwise concentrates sunlight towards a pipe ( 50 ). Fluid ( 60 ) conveyed by the pipe ( 50 ) can be heated to very high temperatures (e.g., up to and above about 100° C., about 200° C., and/or about 300° C.).

Description:
RELATED APPLICATION 
       [0001]    This application claims priority under 35 USC § 119 (e) to U.S. Provisional Patent Application No. 61/702,631 filed on Sep. 18, 2012. The entire disclosure of this provisional patent application is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    A tried-and-true solar energy collection conduit comprises an outer tube having a wall defining a collection chamber, this chamber-defining wall having a ceiling which transmits sunlight therethrough. A pipe resides within a sunlight-absorbing region of the collection chamber and conveys fluid therethrough. Reflectors and shields can be strategically placed to maximize heat transfer to the fluid-conveying pipe. And when optical concentrating lens are added to the equation, it is possible to heat the fluid to very high temperatures (e.g., up to and above about 100° C., about 200° C., and/or about 300° C.). 
       SUMMARY 
       [0003]    A solar energy collection conduit is provided wherein an optical concentrator is incorporated into the outer tube. In this manner, solar energy can be focused along the entire length of the fluid-conveying pipe (as opposed to spaced target areas). 
     
    
     
       DRAWINGS 
         [0004]      FIGS. 1-9  show some possible embodiments of the solar energy collection conduit and the corresponding  FIGS. 1A-9A  show sections of the respective conduit. 
           [0005]      FIG. 10  shows a plurality of the solar energy collection conduits connected in series to form a panel-like cell. 
           [0006]      FIGS. 11-14  show the solar energy collection cell as the fluid-heating component in a power generation system, a water heating system, a desalination system, and a regeneration system. 
       
    
    
     DESCRIPTION 
       [0007]    Referring now to the drawings, and initially to  FIG. 1 , the solar energy collection conduit  10  comprises a collection chamber  20  including a sunlight-absorbing region  21 . An outer tube  30  includes a wall  31  defining the collection chamber  20  and this chamber-defining wall  31  has a ceiling  32  which transmits sunlight therethrough. The chamber  20  can be evacuated and/or it can be filled with a sunlight-absorbing medium. 
         [0008]    An optical concentrator  40  is incorporated into the wall  31  of the outer tube  30 . More particularly, in the embodiment shown in  FIG. 1 , the optical concentrator  40  is incorporated into the light-transmitting ceiling  32  of the wall  31 . The concentrator  40  causes sunlight transmitted through the ceiling  22  to be directed, focused, or otherwise concentrated towards the sunlight-absorbing region  21  of the chamber  20 . 
         [0009]    The light-transmitting ceiling  32  can preferably extend substantially the entire length of the collection chamber  30 . And the optical concentrator  40  can preferably extend substantially the length of the light-transmitting ceiling  32 . 
         [0010]    As only the ceiling  32  need be transparent to sunlight, non-ceiling sections of the wall  31  can be made of a nontransparent material. If the light-transmitting ceiling  32  is formed in one piece with rest of the chamber-defining wall  31 , non-ceiling sections can be made opaque by, for example, painting them black. The chamber-defining wall  31  and/or the light-transmitting ceiling  32  can be made from acrylic (e.g., PMMA), polycarbonate, and/or traditional glass materials. They can be formed by injection molding, compression molding, extrusion, machining, or cell casting. 
         [0011]    The solar energy collection conduit  10  can further comprise a pipe  50  and a fluid  60  which is conveyed therethrough. The fluid-conveying pipe  50  resides in the sunlight-absorbing region  21  of the collection chamber  20 . The pipe  50  can be made of a metal (e.g., copper), ceramic, or any other heat-conducting material. The fluid can be water, seawater, oil, refrigerant, or other suitable liquid or gas. Thanks to the optical concentrator  40 , it is possible to heat the fluid  60  within the pipe  50  to very high temperatures (e.g., up to and above about 100° C., about 200° C., and/or about 300° C.). 
         [0012]    A reflector plate  70  can be positioned to reflect sunlight upwards back into the sunlight-absorbing region  21  of the collection chamber  20 . In the illustrated embodiments, for example, the plate  70  is positioned beneath the fluid-conveying pipe  50 . Other reflection and/or refraction devices can be positioned within the chamber  20 . And conduits  10  and/or chambers  20  without such devices are feasible and foreseeable. 
         [0013]    Referring additionally to  FIG. 1A , the concentrator  40  comprises a substrate  41  and sunlight-concentrating features  42  formed on this substrate  41 . The substrate  41  extends downward from the interior surface  33  of the ceiling  32  and the features  42  are formed on the substrate&#39;s lower surface  43 . The sunlight-concentrating features  42  in this embodiment comprise Fresnel prisms. 
         [0014]    In the conduit  10  shown in  FIG. 2  (and  FIG. 2A ), the sunlight-concentrating features  42  also comprise Fresnel prisms. But in this embodiment, the substrate  41  extends upward from an exterior surface  34  of the ceiling  32  and the sunlight-concentrating features are formed on the substrate&#39;s upper surface  44 . 
         [0015]    In the conduit  10  shown in  FIGS. 3-6 , the sunlight-concentrating features  42  comprise meniscus lens ( FIGS. 3-4 ) or they comprises planoconvex lens ( FIGS. 5-6 ). The substrate  41  can extend downward from the interior surface  33  of the ceiling  32  and the features  42  can be formed on the substrate&#39;s lower surface  43  ( FIG. 3  and  FIG. 5 ). Or the substrate  41  can extend upward from the exterior surface  34  of the ceiling  32  and the features  42  can be formed on the substrate&#39;s upper surface  44  ( FIG. 4  and  FIG. 6 ). 
         [0016]    In the conduit  10  shown in  FIGS. 7-9 , the substrate  41  is situated within the chamber  20  at a location downward from the ceiling  32  and upward from the sunlight-absorbing region  21 . The substrate  41  can extend laterally across the width the wall  31 . The solar-concentrating features  42  can comprise Fresnel prisms ( FIG. 7 ), meniscus lens ( FIG. 8 ), or planoconvex lens ( FIG. 9 ). 
         [0017]    The substrate  41  can be formed in one piece with the chamber-defining wall  31 . Alternatively, the substrate  41  can be formed as a separate piece from the wall  31  and then attached thereto by notching, press-fitting, adhesive, soldering, or other appropriate attachment techniques. A further option is to mold or otherwise form the substrate  41  onto the wall  31 . The features  42  can be formed at the same time as the rest of the substrate  41  and/or they can be featured thereon during a latter manufacturing stage. 
         [0018]    The substrate  41  can be made of any suitable material which is optically transparent, compatible with attachment to the wall  31 , and capable of carrying the sunlight-concentrating features  42 . Acceptable candidates could include, for example, acrylic, polycarbonate, or glass. The substrate  41  and/or the features  42  can be made by injection molding, compression molding, extrusion, machining, and/or cell casting. 
         [0019]    As shown in  FIG. 10 , a plurality of the solar energy collection conduits  10  can be connected in series to form a panel-like cell  80 . 
         [0020]    And as shown in  FIGS. 11-14 , this cell  80  can be the fluid-heating component of a power generation system  91 , a water heating system  92 , a desalination system  93 , or a heat battery reconstitution system  94 . 
         [0021]    One may now appreciate that a solar energy collection conduit  10  is provided wherein an optical concentrator  40  is incorporated into the outer tube  30 . Although the conduit  10 , the chamber  20 , the tube  30 , the concentrator  40 , the pipe  50 , the fluid  60 , the plate  70 , the cell  80 , and/or the systems  91 - 94  have been shown and described with respect to certain embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings.