Solar energy collection system

Abstract

In one aspect of the present invention, a solar energy collection system that includes multiple longitudinally adjacent collectors is described. The collectors are coupled end to end to form a collector row. Each collector includes a reflector, one or more solar receivers and a support structure. There is a space between the support structures of adjacent collectors in the collector row, where the reflectors of the adjacent collectors extend beyond the underlying support structures to form a substantially continuous reflective surface over the space. A coupling device is positioned in the space between the tube assemblies. The coupling device connects and helps to rotate the support structures of the adjacent collectors. Some embodiments relate to various types of coupling devices and collector arrangements.

1 . A solar energy collection system that includes a collector row that extends along a longitudinal axis and tracks the sun in at least one dimension by rotating about a pivot axis, the solar energy collection system comprising:
 a plurality of longitudinally adjacent collectors that are coupled end to end along the longitudinal axis to form the collector row, each collector comprising:
 a reflector; 
 at least one solar receiver; and 
 a support structure that supports the at least one solar receiver and the reflector, there being a space between the support structures of adjacent collectors in the collector row, wherein the reflectors of the adjacent collectors extend beyond the underlying support structures to form a substantially continuous reflective surface over the space; and 
   a coupling device that is positioned in the space between the support structures, the coupling device connecting the support structures of the adjacent collectors and arranged to help rotate the adjacent collectors.   
     
     
         2 . A solar energy collection system as recited in  claim 1 , wherein the reflectors of the collectors in the collector row are arranged to form a substantially continuous flux line on the receivers of the collectors in the collector row. 
     
     
         3 . A solar energy collection system as recited in  claim 1 , wherein a gap between the reflectors of adjacent collectors in the collector row is less than approximately 10 millimeters. 
     
     
         4 . A solar energy collection system as recited in  claim 1 , wherein:
 each solar receiver includes one or more photovoltaic cells; and   a gap between the reflectors of the adjacent collectors is less than at least one selected from the group consisting of: 1) approximately 30% of the width of one of the photovoltaic cells; 2) approximately 20% of the width of one of the photovoltaic cells; and 3) approximately 10% of the width of one of the photovoltaic cells.   
     
     
         5 . A solar energy collection system as recited in  claim 1 , wherein the reflectors of the collector row are arranged to have a range of tilt angles that are at least one selected from the group consisting of: 1) at least ±85° around the pivot axis; 2) at least ±80° around the pivot axis; 3) at least ±75° around the pivot axis; and 4) at least ±70° around the pivot axis. 
     
     
         6 . A solar energy collection system as recited in  claim 1 , wherein:
 no part of the support structure of each collector extends longitudinally beyond the reflector of the collector; and   neither the support structure nor the at least one solar receiver of each collector are positioned in front of an optical aperture of the reflector.   
     
     
         7 . A solar energy collection system as recited in  claim 1 , wherein the coupling device includes at least one alignment feature that is arranged to help hold together the coupling device and the support structures of the adjacent collectors without use of welding. 
     
     
         8 . A solar energy collection system as recited in  claim 1 , wherein a gap between the reflectors of adjacent collectors is covered with a splice, the splice and the reflectors arranged to reflect light to form a substantially continuous flux line on the at least one receiver, the splice being coupled with the reflectors such that movement of the reflectors along the longitudinal axis is allowed. 
     
     
         9 . A solar energy collection system as recited in  claim 1 , wherein:
 the plurality of longitudinally adjacent collectors includes a first collector and a second collector that are arranged adjacent to one another; and   the coupling device is a drive coupling device that is positioned between the support structures of the first and second collectors and includes a motor and a slew drive that is coupled with and driven by the motor, the slew drive arranged to apply rotational torque to the support structures of the adjacent first and second collectors.   
     
     
         10 . A solar energy collection system as recited in  claim 9 , wherein the slew drive includes a stationary portion and a rotatable portion, the rotatable portion being coupled to and arranged to rotate the support structures of the adjacent first and second collectors. 
     
     
         11 . A solar energy collection system as recited in  claim 10 , further comprising a mounting post that supports the drive coupling device, the mounting post including a bottom end and a top end, wherein the bottom end of the mounting post is mounted on the ground and the top end of the mounting post is attached with and physically supports the stationary portion of the slew drive. 
     
     
         12 . A solar energy collection system as recited in  claim 9 , further comprising a planetary drive that is coupled with the motor and the slew drive, the planetary drive arranged to reduce the rotational speed of the motor to a speed appropriate for driving the collector row. 
     
     
         13 . A solar energy collection system as recited in  claim 9 , wherein the plurality of collectors further includes a third collector, the solar energy collection system further comprising:
 a non-drive coupling device that couples the support structure of the third collector with the support structure of the first collector to extend the collector row in the longitudinal direction, the non-drive coupling device arranged to transfer rotational torque from the rotation of the support structure of the first collector to the support structure of the third collector.   
     
     
         14 . A solar energy collection system as recited in  claim 13 , wherein the non-drive coupling device includes a transfer arm that helps connect the support structures of the first and third collectors, the transfer arm including one or more flexible portions that allow the transfer arm to move in the longitudinal direction to help compensate for differential thermal expansion along the length of the collector row. 
     
     
         15 . A solar energy collection system as recited in  claim 7 , wherein each alignment feature includes an alignment hole and a precision dowel that is arranged to fit through the alignment hole to help secure portions of the drive coupling device to portions of the adjacent collectors. 
     
     
         16 . A solar energy collection system as recited in  claim 1 , wherein each solar receiver includes at least one photovoltaic cell. 
     
     
         17 . A solar energy collection system as recited in  claim 1  wherein:
 the reflector of each collector includes a substantially concave reflective surface that is arranged to direct incident sunlight to the at least one solar receiver using a single reflection; 
 the at least one solar receiver of each collector includes a first solar receiver and a second solar receiver, each solar receiver having a photovoltaic cell, the first and second solar receivers being positioned adjacent to one another over a center of the collector, wherein faces of the photovoltaic cells of the first and second solar receivers face away from one another; and 
 at least portions of the at least one solar receiver are positioned at a height that is higher than a top edge of the reflector. 
 
     
     
         18 . A solar energy collection system as recited in  claim 1  wherein:
 the reflector of each collector includes a substantially concave reflective surface that is arranged to direct incident sunlight to the at least one solar receiver using a single reflection; 
 the at least one solar receiver of each collector are positioned at the periphery of the collector; and 
 at least portions of the at least one solar receiver are positioned at a height that is higher then a top edge of the reflector.