Fresnel solar collector arrangement

Abstract

The invention relates to a Fresnel solar collector arrangement consisting essentially of a receiver ( 1 ) and a mirror arrangement associated with the receiver ( 1 ). The arrangement is temperature-compensated by the use of materials with the same temperature expansion coefficient for the receiver mast ( 2 ) and the mirror supporting framework ( 4 ), and the adjustment of the primary mirror ( 6, 6 ′) in relation to the sun by a mechanical coupling of the mirror is simplified by means of an electromotive connecting rod.

1 . Fresnel solar collector arrangement having at least one receiver ( 1 ) mounted on a receiver supporting framework, elevated relative to several primary mirrors ( 6 ,  6 ′) that are disposed on a mirror supporting framework ( 4 ) on both sides of the receiver ( 1 ) so as to pivot, in such a manner that the solar radiation reflected by the primary mirrors ( 6 ) is focused at least essentially onto the receiver ( 1 ), and the primary mirrors ( 6 ) are, in each instance, made to track the sun, wherein the mirror supporting framework ( 4 ) that extends bilaterally outward from the receiver supporting framework is mounted in a fixed location in the region of the receiver supporting framework and/or in connection with the receiver supporting framework and, for the remainder is mounted to slide, i.e. in constraint-free manner, at least to a great extent. 
     
     
         2 . Fresnel solar collector arrangement according to  claim 1 , wherein the receiver supporting framework and the mirror supporting framework ( 4 ) are made from a material having at least largely identical material expansion coefficients, preferably from steel  37 , in each instance. 
     
     
         3 . Fresnel solar collector arrangement according to  claim 1 , wherein the receiver ( 1 ) comprises an absorber tube that is mounted in an elevated manner by means of a row of receiver masts ( 2 ), preferably disposed in an imaginary straight line, which essentially form the receiver supporting framework, and that the mirror supporting framework ( 4 ) comprises supporting rails ( 5 ) that are spaced apart from one another and connected in a framework-like manner by means of appropriate struts, if necessary, whereby these supporting rails ( 5 ) extend outward at least essentially orthogonally from an imaginary straight line of the receiver masts ( 2 ) disposed in a row, and that these supporting rails ( 5 ) are fixed in place in connection with the receiver masts ( 2 ), or in the foundation region of the receiver masts ( 2 ), and otherwise are mounted to slide. 
     
     
         4 . Fresnel solar collector arrangement according to  claim 1 , wherein the primary mirrors ( 6 ,  6 ′) disposed on a common supporting rail ( 5 ) along an imaginary line parallel or perpendicular to the longitudinal expanse of the absorber tube of the receiver ( 1 ), are combined to form a primary mirror group, whereby the primary mirrors ( 6 ,  6 ′) of the primary mirror group are mechanically coupled by means of a common setting element and, as a result, are made to track the sun together. 
     
     
         5 . Fresnel solar collector arrangement according to  claim 4 , wherein the primary mirrors ( 6 ) assigned to one or more supporting rails ( 5 ) disposed in an imaginary extension relative to one another are combined to form a primary mirror group. 
     
     
         6 . Fresnel solar collector arrangement according to  claim 5 , wherein the primary mirrors ( 6 ,  6 ′) of the primary mirror group are, in each instance, mounted to pivot on the supporting rail(s) ( 5 ), whereby these primary mirrors ( 6 ) are rigidly connected with one another by means of a connecting rod ( 10 ,  10 ′), preferably driven by an electric motor, and can be pivoted together, relative to the absorber tube of the receiver ( 1 ), by means of linear movement of the connecting rod ( 10 ,  10 ′) in the direction of the longitudinal expanse of the connecting rod ( 10 ,  10 ′), in terms of their respective angle of incidence. 
     
     
         7 . Fresnel solar collector arrangement according to  claim 6 , wherein the primary mirrors ( 6 ,  6 ′) of a primary mirror group are firmly connected with one another by means of a tracking shaft ( 17 ), for the purpose of common pivoting, which shaft is essentially disposed parallel to the longitudinal expanse of the absorber tube, to rotate relative to the supporting rails ( 5 ). 
     
     
         8 . Fresnel solar collector arrangement according to  claim 7 , wherein the tracking shaft ( 17 ) is mounted in a roller bearing block ( 15 ) that surrounds the shaft, whereby the shaft is held in the roller bearing block ( 15 ) by means of a multiplicity, preferably three, of barrel-shaped roller elements ( 16 ,  16 ′,  16 ″), in such a manner that axial rotation of the tracking shaft ( 17 ) is made possible. 
     
     
         9 . Fresnel solar collector arrangement according to  claim 5 , wherein the connecting rod ( 10 ,  10 ′) can be displaced by a motor in the direction of its longitudinal expanse, by means of a linear motor ( 11 ). 
     
     
         10 . Fresnel solar collector arrangement according to  claim 6 , wherein the linear motor ( 11 ) is preferably disposed in the region of the receiver mast ( 2 ), and one or more connecting rods ( 10 ,  10 ′) are driven by the linear motor ( 11 ), whereby the primary mirrors ( 6 ) disposed on the right of the receiver ( 1 ) are moved opposite the primary mirrors ( 6 ′) on the left of the receiver ( 1 ), for the purpose of tracking, whereby this opposite movement is implemented by means of a corresponding deflection mechanism provided on only one side of the receiver ( 1 ). 
     
     
         11 . Fresnel solar collector arrangement according to  claim 1 , wherein a heat storage medium, preferably steam or thermal oil, flows inside the absorber tube. 
     
     
         12 . Fresnel solar collector arrangement according to  claim 10 , wherein the receiver ( 1 ) additionally comprises a secondary reflector assigned to the absorber tube, which essentially absorbs the scattered radiation reflected by the primary mirrors ( 6 ,  6 ′), and deflects it onto the absorber tube. 
     
     
         13 . Fresnel solar collector arrangement according to  claim 1 , wherein the dimensions and spacings of the primary mirrors ( 6 ,  6 ′) are dimensioned in such a way that mutual shadowing of the primary mirrors ( 6 ,  6 ′) is precluded, at least to a great extent.