Linear fresnel solar arrays and components therefor

Abstract

Described herein are solar energy collector systems, components for solar energy collector systems, and methods for installing solar energy collector systems. The components for solar energy collector systems include but are not limited to solar radiation absorbers, receivers, drives, drive systems, reflectors, and various support structures. The solar energy collection systems, solar radiation absorbers, receivers, drives, drive systems, reflectors, support structures, and/or methods may be used, for example, in LFR solar arrays.

1 . A solar energy collector system comprising:
 an elevated receiver comprising a solar radiation absorber;   first and second reflector fields positioned on opposite sides relative to a center of the receiver;   wherein:   each reflector field comprises reflectors arranged into one or more parallel reflector rows extending generally in a direction parallel to a length of the receiver;   the reflectors each comprise a reflective surface configured to direct incident solar radiation to form a line focus at the solar radiation absorber in the receiver;   the reflectors are configured to be driven to at least partially track diurnal motion of the sun; and   at least one reflector from the first and/or second reflector field has a focal length that is greater than a distance between the reflective surface of the at least one reflector and the solar radiation absorber.   
     
     
         2 . The solar energy collector system of  claim 1 , wherein the one or more parallel reflector rows comprises an outer row, and the at least one reflector having a focal length that is greater than a distance between the reflective surface of the at least one reflector and the solar radiation absorber is positioned in the outer row. 
     
     
         3 . The solar energy collector system of  claim 1 , wherein the at least one reflector has a focal length that is about 1% to about 15% greater than the distance between the reflective surface of the at least one reflector and the solar radiation absorber. 
     
     
         4 . A solar energy collector system comprising:
 an elevated receiver comprising a solar radiation absorber;   first and second reflector fields positioned on opposite sides relative to a center of the receiver;   wherein:   each reflector field comprises reflectors arranged into one or more parallel reflector rows extending generally in a direction parallel to a length of the receiver;   the reflectors each comprise a reflective surface configured to direct incident solar radiation to the solar radiation absorber in the receiver; and   the reflectors are configured to be driven to at least partially track diurnal motion of the sun,   wherein the reflectors are arranged so that a focal length of each reflector is generally correlated with a distance between that reflector and the receiver.   
     
     
         5 . A reflector for use in a solar energy collector system, the reflector comprising a reflective surface configured to direct incident solar radiation to form a line focus at a solar radiation absorber in an elevated receiver, and the reflector configured to be driven to at least partially follow diurnal motion of the sun, wherein the reflector has a focal length greater than a distance between the reflective surface of the reflector and the solar radiation absorber. 
     
     
         6 . The reflector of  claim 5 , wherein the focal length of the reflector is about 1% to about 15% longer than the distance between the reflective surface of the reflector and the solar radiation absorber. 
     
     
         7 . A solar energy collector system comprising:
 an elevated receiver extending in a longitudinal direction;   a vertical support structure configured to support the elevated receiver; and   first and second guy wires,   wherein:   the first guy wire is coupled to the vertical support structure at a first coupling point, extends laterally from the vertical support structure to a first anchoring point, and has a first resonance frequency between the first coupling point and the first anchoring point; and   the second guy wire is coupled to the vertical support structure at a second coupling point, extends laterally from the vertical support structure to a second anchoring point, and has a second resonance frequency between the second coupling point and the second anchoring point, wherein the second resonance frequency is different from the first resonance frequency.   
     
     
         8 . The solar energy collector system of  claim 7 , wherein the first resonance frequency differs from the second resonance frequency by at least about 20 percent. 
     
     
         9 . A set of guy wires, the set comprising first and second guy wires, each of the first and second guy wires comprising a distal end and a proximal end, wherein:
 the distal end of the first guy wire is configured to be coupled to a distal end of a ground-anchored vertical support structure of a solar energy collector system at a first coupling point, and the proximal end of the first guy wire is configured to be anchored to the ground and/or to an anchoring structure at a first anchoring point;   the distal end of the second guy wire is configured to be coupled to the distal end of the vertical support structure at a second coupling point, and the proximal end of the second guy wire is configured to be anchored to the ground and/or to an anchoring structure at a second anchoring point; and   the first guy wire has a first resonance frequency between the first coupling and anchoring points when coupled to the vertical support structure at the first coupling and anchoring points, the second guy wire has a second resonance frequency between the second coupling anchoring points when coupled to the vertical support structure at the second coupling and anchoring points, and the first resonance frequency is different from the second resonance frequency.   
     
     
         10 . The set of guy wires of  claim 9 , further comprising a third guy wire comprising a distal end and a proximal end, wherein the distal end of the third guy wire is configured to be coupled to the vertical support structure at a third coupling point, the proximal end of the third guy wire is configured to be anchored to the ground and/or to an anchoring structure at a third anchoring point, and the third guy wire has a third resonance frequency between the third coupling point and the third anchoring point that is different from at least one of the first and second resonance frequencies. 
     
     
         11 . The set of guy wires of  claim 9 , wherein a length of the first guy wire between the first coupling point and the first anchoring point is different than a length of the second guy wire between the second coupling point and the second anchoring point. 
     
     
         12 . The set of guy wires of  claim 9 , wherein a width of the first guy wire between the first coupling point and the first anchoring point is different than a width of the second guy wire between the second coupling point and the second anchoring point. 
     
     
         13 . A solar energy collector system comprising:
 an elevated receiver comprising a solar radiation absorber;   a plurality of vertical support structures configured to support the elevated receiver, the vertical support structures distributed longitudinally along a length of the elevated receiver; and   an arrangement of longitudinal guy wires, wherein each longitudinal guy wire extends between two adjacent ones of the plurality of vertical support structures, and the vertical support structures and/or the arrangement of longitudinal guy wires are configured to stabilize the solar energy collector system and to accommodate longitudinal thermal expansion of one or more components of the elevated receiver.   
     
     
         14 . The solar energy collector system of  claim 13 , wherein the arrangement of longitudinal guy wires comprises a density of longitudinal guy wires that decreases as a distance from a longitudinal center of the elevated receiver increases. 
     
     
         15 . The solar energy collector system of  claim 13 , wherein the arrangement of longitudinal guy wires comprises a first set of generally parallel single longitudinal guy wires, each single longitudinal guy wire in the first set extending generally in a first diagonal direction between two adjacent ones of the plurality of vertical support structures. 
     
     
         16 . The solar energy collector system of  claim 15 , wherein:
 the arrangement of longitudinal guy wires further comprises a second set of generally parallel single longitudinal guy wires, each single longitudinal guy wire in the second set extending generally in a second diagonal direction between two adjacent ones of the plurality of vertical support structures; and   the first set and second sets of longitudinal guy wires are positioned on opposite sides relative to a longitudinal center of the receiver.   
     
     
         17 . A method of installing a linear Fresnel solar reflector system, the method comprising:
 arranging a plurality of reflectors into reflector rows;   providing a receiver body comprising a receiver channel, the receiver channel comprising first and second sidewalls and an aperture each extending along a length of the receiver channel;   arranging a plurality of solar radiation absorbing tubes lengthwise in the receiver channel;   inserting a window into the receiver channel in a direction transverse to the length of the receiver channel;   securing the window over the aperture so that the window forms a junction with each of the first and second sidewalls of the receiver channel to form a cavity housing the solar radiation absorbing tubes;   orienting the receiver body so that the length of the receiver channel is generally parallel to the reflector rows;   elevating the receiver body comprising the receiver channel, the solar radiation absorber tubes, and the window to an installed vertical receiver position that is above the plurality of reflectors; and   aligning the plurality of reflectors so that each reflector directs incident solar radiation through the window to be at least partially incident on one or more of the solar absorber tubes when the receiver body is in the installed vertical receiver position.   
     
     
         18 . The method of  claim 17 , comprising securing the window to the receiver channel with fasteners before elevating the receiver body to the installed vertical receiver position. 
     
     
         19 . The method of  claim 17 , wherein elevating the receiver body comprises:
 anchoring a proximal end of a jointed vertical support structure to the ground;   angling a distal end of the jointed vertical support structure toward the ground;   securing the receiver body to the distal end of the jointed vertical support structure; and   applying lateral force to the distal end of the jointed vertical support structure to elevate the receiver body.   
     
     
         20 . The method of  claim 17 , comprising applying lateral force to the distal end of the jointed vertical support structure with a tether. 
     
     
         21 . The method of  claim 18 , further comprising threading the tether through one or more pulleys to control the application of lateral force to the distal end of the jointed vertical support structure. 
     
     
         22 . A vertical support structure, comprising:
 a proximal end configured to be anchored to the ground;   a distal end configured to be coupled to an elevated receiver in a solar energy collector system; and   a first joint, wherein the first joint is configured to:
 allow the distal end of the vertical support structure to be angled toward the ground for coupling the receiver thereto at or near ground level while the proximal end of the vertical support structure is anchored to the ground; and 
 allow the distal end of the vertical support structure to be elevated with the application of lateral force to the distal end of the vertical support structure, so that a receiver coupled thereto can be elevated to a vertical installed receiver position. 
   
     
     
         23 . The vertical support structure of  claim 22 , comprising a second joint positioned distally relative to the first joint, wherein:
 the second joint can be flexed independently from the first joint;   the second joint is configured to:
 allow the distal end of the vertical support structure to be angled more toward the ground than the first joint while the proximal end of the vertical support structure is anchored to the ground; and 
 allow the distal end of the vertical support structure to be elevated with application of lateral force to the distal end of the vertical support structure, so that the receiver coupled thereto can be elevated to the vertical installed receiver position. 
   
     
     
         24 . The vertical support structure of  claim 22 , further comprising a tether coupled to the distal end of the vertical support structure, wherein the tether is configured to apply lateral tension to the distal end of the vertical support structure to elevate a receiver coupled thereto. 
     
     
         25 . The vertical support structure of  claim 24 , further comprising one or more pulleys, wherein the tether is configured to be threaded through the one or more pulleys to guide the position of the tether as lateral tension is applied to the distal end of the vertical support structure. 
     
     
         26 . A method for making a carrier frame for supporting reflector elements in a linear Fresnel solar reflector system, the method comprising:
 providing first and second platforms, each platform comprising a first end and an opposite second end;   providing a first reflector support comprising one or more attachment tabs affixed to the first reflector support;   fixing the first reflector support to the second end of the first platform;   temporarily coupling the first reflector support to the first end of the second platform with the one or more attachment tabs so that the first and second platforms each extend from opposite sides of the first reflector support; and   aligning the second platform with the first platform with the one or more attachment tabs.   
     
     
         27 . The method of  claim 26 , further comprising fixing the first end of the second platform to the first reflector support after aligning the first platform with the second platform. 
     
     
         28 . The method of  claim 26 , further comprising providing second and third reflector supports, wherein the second reflector support is coupled to the first end of the first platform so that the first platform is supported between the first and second reflector supports, and the third reflector support is coupled to the second end of the second platform so that the second platform is supported between the first and third reflector supports. 
     
     
         29 . The method of  claim 26 , comprising aligning the first platform with the second platform to within about 5 mm. 
     
     
         30 . A carrier frame for supporting reflector elements in a linear Fresnel reflector system, the carrier frame comprising:
 first and second platforms, each platform comprising first and second ends; and   a first reflector support comprising a first side and a second opposite side, and at least one attachment tab affixed to the first reflector support, wherein:   the second end of the first platform is fixed to the first side of the first reflector support;   the first end of the second platform is removably attached to the first reflector support with at least one attachment tab, so that the first and second platforms extend from opposite sides of the first reflector support; and   the at least one attachment tab is configured to allow alignment of the second platform relative to the first platform and to allow securing of the second platform to the first reflector support in an aligned position.   
     
     
         31 . The carrier frame of  claim 30 , further comprising second and third reflector supports, wherein the second reflector support is fixed to the first end of the first platform so that the first platform is supported between the first and second reflector supports, and the third reflector support is fixed to the second end of the second platform so that the second platform is supported between the first and third reflector supports. 
     
     
         32 . The carrier frame of  claim 30 , wherein the attachment tab comprises a threaded hole configured to accept a threaded bolt coupled to the second platform. 
     
     
         33 . The carrier frame of  claim 30 , wherein the attachment tab is configured to allow rotation and/or translation of the second platform to align the second platform with the first platform. 
     
     
         34 . A method for installing an elevated receiver into a solar energy collector system, the method comprising:
 anchoring a vertical support structure to the ground; and   lifting a receiver with a hoist coupled to the vertical support structure; and   coupling the receiver to the vertical support structure to install the receiver in the solar energy collector system.   
     
     
         35 . The method of  claim 34 , wherein the vertical support structure comprises a shelf, and coupling the receiver to the vertical support structure comprises supporting the receiver on the shelf. 
     
     
         36 . The method of  claim 34 , comprising:
 anchoring a row of vertical support structures to the ground, at least one of the vertical support structures comprising a hoist;   positioning an elongated receiver at or near ground level along the row of vertical support structures;   lifting the elongated receiver with the hoist; and   coupling the elongated receiver to the row of vertical support structures to install the receiver in the solar energy collector system.   
     
     
         37 . The method of  claim 34 , comprising removing the hoist after the receiver has been installed. 
     
     
         38 . A vertical support structure for use in a solar energy collector system, the vertical support structure comprising:
 at least one post configured to be anchored to the ground;   a hoist configured to lift an elevated receiver; and   at least one mounting member configured to support the receiver in an elevated installed position.   
     
     
         39 . The vertical support structure of  claim 38 , wherein the at least one mounting member comprises a shelf. 
     
     
         40 . The vertical support structure of  claim 38 , comprising two posts, each post configured to be coupled to the ground, wherein the posts are angled toward each other and interconnected at or near a peak of the vertical support structure. 
     
     
         41 . The vertical support structure of  claim 38 , wherein the hoist is mounted to an auxiliary portion of the vertical support structure, and the auxiliary portion is configured to be removed after the receiver is installed. 
     
     
         42 . The method of  claim 17 , wherein elevating the receiver body to an installed vertical receiver position comprises:
 anchoring at least one post of a vertical support structure to the ground;   elevating the receiver body with a hoist coupled to the vertical support structure; and   coupling the elevated receiver body to the vertical support structure.