Solar heating reflecting element suitable for molding

Abstract

A solar energy collecting apparatus for heating a working fluid using the plurality of substantially identical reflective elements arranged in rows is provided. Each reflective element comprises a substantially rectangular element having opposing side walls and opposing end walls which together form a bottom edge for supporting the reflective element on a flat support such as a sheet metal or molded base. Each reflective element further includes a top wall connected with and supported by the side walls and the end walls. The top wall is formed to provide a reflective surface facing away from the bottom edge and is formed in a shape for reflecting solar radiation falling thereon, from a range of incident angles, to a focal axis. The focal axis of each reflective element is substantially parallel with a longitudinal axis of the reflective element and when the reflective elements are arranged in parallel rows, each row includes a focal axis along its longitudinal length. The reflective surface is coated with a reflective layer such as vacuum deposited aluminum, metabolized paint or by other reflective coatings to reflect solar energy to the focal axis. Ideally, the reflective element is formed by molding a material in a mold such that the mold forms the shape of the reflective surface. In the preferred embodiment of the present invention the reflective element is molded in a press mold from a material comprising hydrated silicates of aluminum which is plastic when wet but which becomes a hard ceramic when fired in an oven. In another aspect of the invention, a solar energy collecting apparatus comprises a working fluid conduit comprising a plurality of fluid carrying members positioned one above each row of reflective elements and substantially coincident with the focal axis of the row. The fluid carrying members are connected together by a plurality of connecting members such that a continuous working fluid conduit passes a working fluid over each row of reflective elements. The working fluid conduit may be movably supported with respect to the base such that each of the plurality of fluid carrying members is movable away from the focal axis when no heating of the working fluid is desired.

What I claim and desire to secure by Letters of Patent of the United States are the following:  
     
         1 . A solar energy collecting apparatus for heating a working fluid comprising: 
 a plurality of substantially identical reflective elements arranged in rows each reflective element including a reflective surface formed in a shape and coated with a reflective layer to reflect solar energy incident thereon to a focal axis;    a working fluid conduit comprising a plurality of fluid carrying members positioned one above each row of reflective elements and substantially coincident with the focal axis, each fluid carrying member being connected with another fluid carrying member by a connecting member such that a continuous working fluid conduit passes a working fluid over each row of reflective elements; and,    a base member for fixedly supporting the reflective elements in rows and for supporting the fluid carrying members of the working fluid conduit.    
     
     
         2 . The solar energy collecting apparatus according to  claim 1  wherein the working fluid conduit is movably supported with respect to the base and the plurality of substantially identical reflective elements arranged in rows such that each of the plurality of fluid carrying members is movable away from the focal axis.  
     
     
         3 . The solar energy collecting apparatus according to  claim 1  wherein each of the reflective elements is formed by molding a material in a mold and wherein the mold forms the shape of the reflective surface.  
     
     
         4 . The solar energy collecting apparatus according to  claim 3  wherein the mold is a press mold.  
     
     
         5 . The solar energy collecting apparatus according to  claim 3  wherein the material comprises hydrated silicates of aluminum which is plastic when wet but which becomes a hard ceramic when fired in an oven.  
     
     
         6 . The solar energy collecting apparatus according to  claim 1  wherein the reflective layer is selected from the group consisting of, a reflective paint, a metalized layer and an adhesive backed reflective coating.  
     
     
         7 . The solar energy collecting apparatus according to  claim 5  wherein the reflective layer comprises a metalized layer deposited by electro-plating.  
     
     
         8 . The solar energy collecting apparatus according to  claim 5  wherein the reflective layer comprises a layer of metal aluminum applied by vacuum deposition.  
     
     
         9 . The solar energy collecting apparatus according to  claim 1  further comprising a pump for pumping the working fluid through the continuous working conduit.  
     
     
         10 . The solar energy collecting apparatus according to  claim 2  further comprising: 
 four hydraulic pistons attached to the base such that one piston is positioned substantially at each corner of the solar collector and wherein a hydraulic flow circuit passes a fluid at a high pressure to each of the four hydraulic pistons;  
 two support brackets each supported at distal ends thereof by one of the four hydraulic pistons hydraulic piston, and wherein each of the support brackets supports one end of each of each of the fluid carrying members such that when the fluid is at the high pressure each of the support bracket is raised by the hydraulic pistons thereby raising each of the fluid carrying members to a position which is substantially coincident with the focal axis and further wherein when the fluid is at a low pressure each of the support brackets is lowered to move each of the fluid carrying members away from the focal axis.  
 
     
     
         11 . The solar energy collecting apparatus acoording to  claim 10  wherin the fluid is the working fluid.  
     
     
         12 . The solar energy collecting apparatus according to  claim 11  further comprising a pump for pumping the working fluid through the continuous working conduit and the hydraulic flow circuit.  
     
     
         13 . The solar energy collecting apparatus according to  claim 10  further comprising: 
 a fours sided enclosure comprising two opposing side member and two opposing end members each fastened to the base for enclosing the rows of reflective elements, the four hydraulic pistons and the working fluid conduit; and  
 an enclosure cover comprising a transparent top for allowing sunlight to enter the enclosure and fall onto the reflective elements, the cover being fastened to the four sided enclosure by a bracket such that the cover and the four sided enclosure and the base form an chamber enclosing the reflective elements and the working fluid conduit and wherein the chamber is substantially sealed form outside air to reduce convective heat lose from the working fluid conduit as the working fluid passes through the solar collector.  
 
     
     
         14 . The solar energy collecting apparatus according to  claim 1  wherein each of the rows comprises a plurality of reflective elements assembled together.  
     
     
         15 . The solar energy collecting apparatus according to  claim 1  wherein each of the fluid carrying members comprises a hollow tube having an elliptical shape and wherein the long axis of the ellipse is substantially parallel to the base.  
     
     
         16 . A reflective element for reflecting solar energy to a focal axis in a solar collecting apparatus comprising: 
 a substantially rectangular element having opposing side walls and opposing end walls which together form a bottom edge for supporting the reflective element on a flat support member and further comprising a top wall connected with and supported by the side walls and the end walls, and wherein the top wall further includes;    a reflective surface facing away from the bottom edge and formed in a shape for reflecting solar radiation falling thereon from a range of incident angle to a focal axis said focal axis being substantially parallel with a longitudinal axis of the reflective element; and,    wherein the reflective surface is coated with a reflective layer for reflecting solar energy.    
     
     
         17 . The reflective element according to  claim 16  wherein the reflective surface has a constant radius R with respect to a locus axis positioned above the reflective surface and wherein the focal axis lies equidistant from the reflective surface and the locus axis.  
     
     
         18 . The reflective element according to  claim 16  wherein the reflective surface has a surface conforming to a shape defined by the set of points M (X, Y) wherein a vertex of the shape lies at the point V=(0, 0) and wherein Y 2 =2pX and further wherein the focal axis of the surface is positioned at the point F=(p/2, 0).  
     
     
         19 . The reflective element according to  claim 18  wherein p falls in the range of 0.5 to 3 inches.  
     
     
         20 . The reflective element according to  claim 17  wherein R falls in the range of 2 to 6 inches.  
     
     
         21 . The solar energy collecting apparatus according to  claim 16  wherein the reflective element is formed by molding a material in a mold and wherein the mold forms the shape of the reflective surface.  
     
     
         22 . The reflective element according to  claim 21  wherein the mold is a press mold.  
     
     
         23 . The reflective element according to  claim 21  wherein the molding material comprises hydrated silicates of aluminum which is plastic when wet but which becomes a hard ceramic when fired in an oven.  
     
     
         24 . A method for heating a working fluid with solar radiation comprising the steps of: 
 attaching a plurality of substantially identical reflective elements each having a focal axis to a base arranged in a plurality of rows such that each row includes a focal axis which is substantially parallel with a longitudinal axis the row;    supporting a working fluid conduit on the base comprising a plurality of fluid carrying members positioned one above each row of reflective elements in a position which is substantially coincident with the focal axis; and,    interconnecting each fluid carrying member with another fluid carrying member by a connecting member such that a continuous working fluid conduit passes a working fluid over each row of reflective elements; and,    pumping a working fluid through the working fluid conduit while the reflective elements are exposed to sun light.    
     
     
         25 . The method according to  claim 24  further comprising the step of moving the working fluid conduit with respect to the base and the plurality of rows such that each of the plurality of fluid carrying members is movable away from the focal axis.  
     
     
         26 . The method according to  claim 24  further comprising the step of forming each of the reflective elements by molding a material in a mold and wherein the mold forms the shape of the reflective surface.  
     
     
         27 . The method according to  claim 24  further comprising the step of supporting the solar collecting apparatus by an adjustable support frame for supporting the solar collecting apparatus in a desired orientation with respect to the sun.  
     
     
         28 . A method for making a reflective element for reflecting solar energy to a focal axis in a comprising the steps of: 
 forming an element having opposing side walls and opposing end walls which together form a bottom edge for supporting the reflective element on a flat support member and further comprising a top wall connected with and supported by the side walls and the end walls;    forming a reflective surface facing away from the bottom edge in a shape for reflecting solar radiation falling thereon from a range of incident angle to a focal axis, said focal axis being substantially parallel with a longitudinal axis of the reflective element; and,    coating the reflective surface with a reflective layer for reflecting solar energy to the focal axis.    
     
     
         28 . The method according to  claim 27  further comprising the step of forming the reflective surface with a constant radius R with respect to a locus axis positioned above the reflective surface and wherein the focal axis lies equidistant from the reflective surface and the locus axis.  
     
     
         29 . The method according to  claim 27  further comprising the step of forming the reflective surface to conform to a shape defined by the set of points M (X, Y) wherein a vertex of the shape lies at V=(0, 0) and wherein Y 2 =2pX and further wherein the focal axis of the surface is positioned at the point F=(p/2, 0).