Apparatuses and methods for providing a secondary reflector on a solar collector system

Abstract

A solar collector system is provided that comprises an absorber tube, a primary reflector, and a secondary reflector. In certain embodiments, the primary and secondary reflectors are positioned on opposing sides of the absorber tube, such that their respective focal points converge upon a longitudinal axis of the absorber tube. The secondary reflector may be configured with a substantially transparent surface facing away from the absorber tube, so as to permit passage of light beams there-through. Opposing surfaces of the secondary and primary reflectors, namely those facing substantially toward the absorber tube contain a reflective coating thereon to facilitate redirection of light beams toward the absorber tube. The solar collector system includes in certain embodiments a frame assembly, whereby the primary reflector, the secondary reflector, and the absorber tube are all configured to unitarily rotate about a common pivot axis defined by at least a portion of the frame assembly.

That which is claimed: 
     
         1 . A solar collector system, said system comprising:
 an absorber tube;   a primary reflector having a primary reflective surface portion configured to substantially reflect one or more light beams making contact therewith substantially toward the absorber tube; and   a secondary reflector having a secondary reflector surface portion configured to reflect the one or more light beams reflected from the primary reflector further toward the absorber tube,   wherein the absorber tube is positioned intermediate the primary reflector and the secondary reflector, such that the absorber tube is configured to collect one or more of the light beams reflected from the primary reflector surface portion and one or more of the light beams reflected from the secondary reflector surface portion.   
     
     
         2 . The solar collector system of  claim 1 , said system further comprising a frame assembly configured to define a unitary pivot axis, wherein the primary reflector, the secondary reflector, and the absorber tube are operatively attached to at least a portion of the frame assembly the first support member such that the primary reflector, the secondary reflector, and the absorber tube rotate as a single unit, said single unit being configured to rotate substantially about said unitary pivot axis whereas the primary reflector, the secondary reflector, and the absorber tube each remain stationary relative to one another so as to minimize misalignment there-between. 
     
     
         3 . The solar collector system of  claim 2 , wherein said unitary pivot axis substantially corresponds with a center of gravity of said single unit formed by the primary reflector, the secondary reflector, and the absorber tube. 
     
     
         4 . The solar collector system of  claim 3 , wherein longitudinal axes of the secondary reflector and the absorber tube are offset relative to said unitary pivot axis. 
     
     
         5 . The solar collector system of  claim 2 , wherein:
 the frame assembly comprises a first support member and a second support member;   the first support member comprises at least one elongate member having a distal end, adjacent to which said secondary reflector is operatively mounted, so as to offset a longitudinal axis of the secondary reflector from said unitary pivot axis a distance corresponding generally to a length of said at least one elongate member; and   the second support member comprises at least one elongate member having a distal end, adjacent to which said absorber tube is operatively mounted, so as to offset a longitudinal axis of the absorber tube from said unitary pivot axis a distance corresponding generally to a length of said at least one elongate member.   
     
     
         6 . The solar collector system of  claim 5 , wherein said length of said at least one elongate member of said first support member is substantially greater than said length of said at least one elongate member of said second support member, such that said absorber tube is positioned substantially intermediate said primary reflector and said secondary reflector. 
     
     
         7 . The solar collector system of  claim 2 , wherein said unitary pivot axis is configured to permit concurrent rotation of said primary reflector, said secondary reflector, and said absorber tube through an angle of up to 270 degrees. 
     
     
         8 . The solar collector system of  claim 1 , wherein said primary reflector comprises a substantially parabolic trough reflector, said substantially parabolic trough reflector defining a substantially parabolic arc, said substantially parabolic arc having a focal point. 
     
     
         9 . The solar collector system of  claim 8 , wherein said substantially parabolic arc has a diameter lying in a range of from approximately three meters to approximately seven meters. 
     
     
         10 . The solar collector system of  claim 9 , wherein said diameter is approximately five meters. 
     
     
         11 . The solar collector system of  claim 8 , wherein said focal point defines a focal line, said focal line being substantially aligned with a longitudinal axis of said absorber tube. 
     
     
         12 . The solar collector system of  claim 11 , wherein said focal line and said longitudinal axis of said absorber tube are positioned a distance relative to said parabolic trough reflector, said distance lying in a range of from approximately 1.5 meters to approximately 4.5 meters. 
     
     
         13 . The solar collector system of  claim 12 , wherein said distance is between approximately 2.0 and 2.5 meters. 
     
     
         14 . The solar collector system of  claim 8 , wherein said focal point is calculated by dividing a square of a diameter of the parabolic arc by the result of multiplying a depth of the parabolic arc by sixteen. 
     
     
         15 . The solar collector system of  claim 8 , wherein said substantially parabolic trough reflector is formed from two distinct mirror panels, each of said mirror panels being positioned on opposing sides of a unitary pivot axis substantially parallel to a longitudinal axis of said primary reflector. 
     
     
         16 . The solar collector system of  claim 1 , wherein said secondary reflective surface portion of said secondary reflector is formed by a substantially reflective coating, said reflective coating having unidirectional reflective properties, such that light beams may pass there-through substantially unhindered in at least one direction. 
     
     
         17 . The solar collector system of  claim 1 , wherein said secondary reflector comprises a substantially parabolic trough reflector, said substantially parabolic trough reflector defining a substantially parabolic arc, said substantially parabolic arc having a focal point. 
     
     
         18 . The solar collector system of  claim 17 , wherein said substantially parabolic arc has a diameter lying in a range of from approximately one meters to approximately three meters. 
     
     
         19 . The solar collector system of  claim 17 , wherein said focal point defines a focal line, said focal line being substantially aligned with a longitudinal axis of said absorber tube. 
     
     
         20 . The solar collector system of  claim 19 , wherein said focal line and said longitudinal axis of said absorber tube are positioned a distance apart from said secondary reflector, said distance lying in a range of from approximately 0.25 meters to approximately 2.5 meters. 
     
     
         21 . The solar collector system of  claim 17 , wherein said secondary reflector is formed from two distinct mirror panels, each of said mirror panels being positioned on opposing sides of a unitary pivot axis that is substantially parallel to a longitudinal axis of said primary reflector. 
     
     
         22 . The solar collector system of  claim 17 , wherein said primary reflector comprises a substantially parabolic trough reflector, said substantially parabolic trough reflector defining a substantially parabolic arc, said substantially parabolic arc having a focal point. 
     
     
         23 . The solar collector system of  claim 17 , wherein said secondary reflector comprises a dual parabolic trough reflector, said dual parabolic trough reflector defining at least two substantially parabolic arcs, each substantially parabolic arc having a focal point corresponding substantially with a longitudinal axis of said absorber tube. 
     
     
         24 . A solar collector system, said system comprising:
 a frame assembly configured to define a unitary pivot axis;   a primary reflector, the primary reflector being operatively attached to at least a portion of said frame assembly;   a secondary reflector, the secondary reflector being operatively attached to at least a portion of said frame assembly; and   an absorber tube, the absorber tube being operatively attached to at least a portion of said frame assembly such that the absorber tube is positioned substantially intermediate the primary reflector and the secondary reflector,   wherein the primary reflector, the secondary reflector, and the absorber tube form a single unit, said single unit being configured to rotate substantially about the unitary pivot axis whereas the primary reflector, the secondary reflector, and the absorber tube each remain stationary relative to one another so as to minimize misalignment there-between.   
     
     
         25 . A method of using a solar collector system to maximize collection of light beams directed thereon by an external light source, the method comprising the steps of:
 (A) providing a system comprising:
 (1) a frame assembly configured to define a unitary pivot axis; 
 (2) a primary reflector, the primary reflector being operatively attached to at least a portion of the frame assembly; 
 (3) a secondary reflector, the secondary reflector being operatively attached to at least a portion of the frame assembly; and 
 (4) an absorber tube, the absorber tube being operatively attached to at least a portion of the frame assembly such that the absorber tube is positioned intermediate the primary reflector and the secondary reflector and the primary reflector, the secondary reflector, and the absorber tube form a single unit; 
   (B) positioning said single unit in a first orientation, said first orientation corresponding to a position at which, during a first period of time, a volume of light beams directed onto said primary reflector is maximized; and   (C) rotating said single unit to a second orientation, said second orientation corresponding to a position at which, during a second period of time different from said first period of time, said volume of light beams directed onto said primary reflector is maximized, wherein said rotating occurs about said unitary pivot point such that the primary reflector, the secondary reflector, and the absorber tube within the single unit each remain stationary relative to one another so as to minimize misalignment there-between.