TERRAIN FOLLOWING SOLAR TRACKER
A solar tracker, solar array, and method of designing a solar tracker or array including a plurality of piers, a torque tube supported by the piers, each pier having a common reveal from the earth and the torque tube has a relative angle from a first pier to a second pier of between 0.25 and about 0.75 degrees.
1 . A terrain following solar tracker comprising:
a plurality of piers mounted into a non-uniformly sloped terrain and arranged in a row, one or more of the plurality of piers being at differing heights relative to other piers of the plurality of piers due to the non-uniformly sloped terrain;
a continuous torque tube extending along the plurality of piers at the differing heights such that the continuous torque tube substantially follows a contour of the non-uniformly sloped terrain, the continuous torque tube formed of a plurality of torque tube sections, the continuous torque tube supported by a plurality of bearing assemblies that are respectively mounted on the plurality of piers at the differing heights relative to one another, the continuous torque tube bending to conform to the plurality of piers at the differing heights as the continuous torque tube extends along the plurality of piers;
a first section of the plurality of torque tube sections extending from a first pier of the plurality of piers to a second pier of the plurality of piers; and
a second section of the plurality of torque tube sections extending from the second pier of the plurality of piers to a third pier of the plurality of piers, the piers being at differing heights causing bending along the first section to form a relative angle between the first section and the second section of up to 0.75 degrees to enable the continuous torque tube to follow contour variations in the non-uniformly sloped terrain.
2 . The terrain following solar tracker of claim 1 , wherein the relative angle formed between the first section and the second section is a difference between a first slope measured near a midpoint of the first section and a second slope measured near a midpoint of the second section.
3 . The terrain following solar tracker of claim 1 , wherein the relative angle formed between the first section and the second section is a difference between a first average angle measured from the first pier to the second pier and a second average angle measured from the second pier to the third pier.
4 . The terrain following solar tracker of claim 1 , wherein a difference in pier height from the first pier to the second pier is between 0 and 15 inches.
5 . The terrain following solar tracker of claim 4 , wherein a difference in pier height from the first pier to the second pier is between 1.5 and 4.5 inches.
6 . The terrain following solar tracker of claim 1 , wherein a maximum north-south slope is between 3.5 and 10 degrees.
7 . The terrain following solar tracker of claim 1 , wherein one or more relative angles formed between adjacent torque tube sections of the plurality of torque tube sections varies along the continuous torque tube such that the continuous torque tube is substantially parallel to the contour variations in the rolling terrain.
8 . The terrain following solar tracker of claim 1 , wherein one or more relative angles formed between adjacent torque tube sections of the plurality of torque tube sections varies along the continuous torque tube such that the continuous torque tube follows elevational variations in the rolling terrain.
9 . The terrain following solar tracker of claim 1 , wherein the continuous torque tube is pre-loaded to conform to the plurality of piers at the differing heights as the continuous torque tube extends along the plurality of piers, and wherein a difference in pier height from the first pier to the second pier causes pre-loading along the first section to enable the continuous torque tube to follow contour variations in the rolling terrain.
10 . The terrain following solar tracker of claim 9 , wherein one or more relative angles formed between adjacent torque tube sections varies along the continuous torque tube such that the bending and pre-loading of the continuous torque tube causes the continuous torque tube to follow elevational variations in the rolling terrain.
11 . The terrain following solar tracker of claim 1 , wherein each torque tube section of the plurality of torque tube sections has a first swaged end and a second unswagged end such that the first swaged ends are inserted into the second unswagged ends to form the continuous torque tube.
12 . The terrain following solar tracker of claim 11 , wherein the first swaged ends of the plurality of torque tube sections being inserted into the second unswagged ends of the plurality of torque tube sections forms overlapping sections having a double-wall thickness.
13 . The terrain following solar tracker of claim 12 , wherein one or more of the overlapping sections is disposed proximate one or more piers of the plurality of piers.
14 . The terrain following solar tracker of claim 13 , wherein the overlapping sections are placed proximate the piers of the plurality of piers where bending moments caused by bending of the continuous torque tube are highest.
15 . The terrain following solar tracker of claim 1 , wherein the continuous torque tube formed of the plurality of torque tube sections is a pre-loaded continuous torque tube.
16 . The terrain following solar tracker of claim 15 , wherein the pre-loaded continuous torque tube passes through the plurality of bearing assemblies that are respectively mounted on the piers at the differing heights.
17 . The terrain following solar tracker of claim 15 , wherein a central longitudinal axis of the first section of the continuous torque tube is angularly deflected from a central longitudinal axis of the second section of the continuous torque tube up to 0.75 degrees to enable the continuous torque tube to follow contour variations in the rolling terrain.
18 . A terrain following solar tracker comprising:
a plurality of piers mounted into a non-uniformly sloped terrain and arranged in a row, one or more of the plurality of piers being at differing heights relative to other piers of the plurality of piers due to the non-uniformly sloped terrain;
a continuous torque tube extending along the plurality of piers at the differing heights such that the continuous torque tube substantially follows a contour of the non-uniformly sloped terrain, the continuous torque tube formed of a plurality of torque tube sections, the continuous torque tube supported by a plurality of bearing assemblies that are respectively mounted on the plurality of piers at the differing heights relative to one another, the continuous torque tube bending to conform to the plurality of piers at the differing heights as the continuous torque tube extends along the plurality of piers;
a first section of the plurality of torque tube sections extending from a first pier of the plurality of piers to a second pier of the plurality of piers; and
a second section of the plurality of torque tube sections extending from the second pier of the plurality of piers to a third pier of the plurality of piers, the piers being at differing heights causing bending along the first section of up to 0.75 degrees to enable the continuous torque tube to follow contour variations in the non-uniformly sloped terrain.
19 . The terrain following solar tracker of claim 18 , wherein a difference in pier height from the first pier to the second pier is between 0 and 15 inches.
20 . The terrain following solar tracker of claim 19 , wherein a difference in pier height from the first pier to the second pier is between 1.5 and 4.5 inches.
21 . The terrain following solar tracker of claim 18 , wherein a maximum north-south slope is between 3.5 and 10 degrees.
22 . The terrain following solar tracker of claim 18 , wherein one or more relative angles formed between adjacent torque tube sections of the plurality of torque tube sections varies along the continuous torque tube such that the continuous torque tube is substantially parallel to the contour variations in the rolling terrain.
23 . The terrain following solar tracker of claim 18 , wherein one or more relative angles formed between adjacent torque tube sections of the plurality of torque tube sections varies along the continuous torque tube such that the continuous torque tube follows elevational variations in the rolling terrain.
24 . The terrain following solar tracker of claim 18 , wherein the continuous torque tube is pre-loaded to conform to the plurality of piers at the differing heights as the continuous torque tube extends along the plurality of piers, and wherein a difference in pier height from the first pier to the second pier causes pre-loading along the first section to enable the continuous torque tube to follow contour variations in the rolling terrain.
25 . The terrain following solar tracker of claim 24 , wherein one or more relative angles formed between adjacent torque tube sections varies along the continuous torque tube such that the bending and pre-loading of the continuous torque tube causes the continuous torque tube to follow elevational variations in the rolling terrain.
26 . The terrain following solar tracker of claim 18 , wherein each torque tube section of the plurality of torque tube sections has a first swaged end and a second unswagged end such that the first swaged ends are inserted into the second unswagged ends to form the continuous torque tube.
27 . The terrain following solar tracker of claim 26 , wherein the first swaged ends of the plurality of torque tube sections being inserted into the second unswagged ends of the plurality of torque tube sections forms overlapping sections having a double-wall thickness.
28 . The terrain following solar tracker of claim 27 , wherein one or more of the overlapping sections is disposed proximate one or more piers of the plurality of piers.
29 . The terrain following solar tracker of claim 28 , wherein the overlapping sections are placed proximate the piers of the plurality of piers where bending moments caused by bending of the continuous torque tube are highest.
30 . The terrain following solar tracker of claim 18 , wherein the continuous torque tube formed of the plurality of torque tube sections is a pre-loaded continuous torque tube.
31 . The terrain following solar tracker of claim 30 , wherein the pre-loaded continuous torque tube passes through the plurality of bearing assemblies that are respectively mounted on the piers at the differing heights.
32 . The terrain following solar tracker of claim 30 , wherein a central longitudinal axis of the first section of the continuous torque tube is angularly deflected from a central longitudinal axis of the second section of the continuous torque tube up to 0.75 degrees to enable the continuous torque tube to follow contour variations in the rolling terrain.