U.S. patent application number 11/577323 was filed with the patent office on 2007-09-20 for system for supporting energy conversion modules.
This patent application is currently assigned to ARIZONA PUBLIC SERVICE COMPANY. Invention is credited to Herbert T. Hayden.
Application Number | 20070215145 11/577323 |
Document ID | / |
Family ID | 37660554 |
Filed Date | 2007-09-20 |
United States Patent
Application |
20070215145 |
Kind Code |
A1 |
Hayden; Herbert T. |
September 20, 2007 |
System for Supporting Energy Conversion Modules
Abstract
A structure (26) for supporting an array (22) of solar panels
(24) in a solar energy collection system (20) includes a support
assembly (140) formed from a ganged pier (44). The ganged pier (44)
includes a truss (68), a post (46) downwardly extending from the
truss (68) for attachment to a footing (48), and posts (50)
upwardly extending from the truss (68). The structure (26) further
includes torsion tubes (34), each of which is pivotally retained by
one of the posts (50) to form parallel rows (32) of torsion tubes
(34). Multiple ganged piers (44) can be interconnected to increase
the number of rows (32) of the system (20). The solar panels (24)
are attached to the torsion tubes (34) to form the array (22).
Inventors: |
Hayden; Herbert T.; (Tempe,
AZ) |
Correspondence
Address: |
MESCHKOW & GRESHAM, P.L.C.
5727 NORTH SEVENTH STREET, SUITE 409
PHOENIX
AZ
85014
US
|
Assignee: |
ARIZONA PUBLIC SERVICE
COMPANY
400 North Fifth Street
Phoenix
AZ
85004
|
Family ID: |
37660554 |
Appl. No.: |
11/577323 |
Filed: |
April 28, 2006 |
PCT Filed: |
April 28, 2006 |
PCT NO: |
PCT/US06/16202 |
371 Date: |
April 14, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11184661 |
Jul 18, 2005 |
7252083 |
|
|
11577323 |
Apr 14, 2007 |
|
|
|
Current U.S.
Class: |
126/704 |
Current CPC
Class: |
F24S 25/617 20180501;
F24S 30/425 20180501; F24S 2025/017 20180501; Y02E 10/47 20130101;
F24S 2030/136 20180501; F24S 2030/16 20180501 |
Class at
Publication: |
126/704 |
International
Class: |
F24J 2/38 20060101
F24J002/38 |
Claims
1. A structure (26) for supporting an array (22) of energy
conversion modules (24) above a surface (28) comprising: an
elongated rigid member (68); a first base (46) supporting said
rigid member (68); a second base (46) spaced apart from said first
base (46) and supporting said rigid member (68), said first and
second bases (46) being configured for attachment to said surface
(28); posts (50) extending from a top edge (72) of said rigid
member (68); and torsion tubes (34), one each of said torsion tubes
(34) being pivotally retained by one each of said posts (50) to
form parallel rows (32) of said torsion tubes (34), said torsion
tubes (34) being configured for attachment of said energy
conversion modules (24) to form said array (22).
2. A structure (26) as claimed in claim 1 wherein said elongated
rigid member (68) comprises a truss.
3. A structure (26) as claimed in claim 1 wherein said rigid member
(68) is a first rigid member (68a), said posts are first posts
(50), said torsion tubes (34) are first torsion tubes, and said
structure (26) further comprises: a second elongated rigid member
(68b) having a second end (86) coupled with a first end (84) of
said first rigid member (68a), said second base (46) further
supporting said second rigid member (68b); second posts (50)
extending from a second top edge (72) of said second rigid member
(68b); and second torsion tubes (34), one each of said second
torsion tubes (34) being pivotally retained by one each of said
second posts (50) to form additional parallel rows (32) of said
second torsion tubes (34) that are substantially parallel to said
parallel rows (32) of said first torsion tubes (34), said second
torsion tubes (34) being configured for attachment of additional
ones of said energy conversion modules (24).
4. A structure (26) as claimed in claim 3 further comprising a
connector (80) coupled to one of said first end (84) of said first
rigid member (68a) and said second end (86) of said second rigid
member (68b), and said connector (80) being slidably coupled with
the other of said first end (84) of said first rigid member (68a)
and said second end (86) of said second rigid member (68b).
5. A structure (26) as claimed in claim 1 wherein said rigid member
(68) is a first rigid member (68), said posts (50) are first posts,
and said structure (26) further comprises: a second elongated rigid
member (68) in substantially parallel, spaced-apart alignment with
said first rigid member (68); a third base (46) supporting said
second rigid member (68) and being configured for attachment to
said surface (28); and second posts (50) extending from a second
top edge (72) of said second rigid member (68), said second posts
(50) being in parallel alignment with said first posts (50) and
pivotally retaining said torsion tubes (34).
6. A structure (26) as claimed in claim 1 further comprising: a
drive mechanism (38) having a body (92) configured for attachment
to said surface (28) and a rod member (96) extendible from said
body (92); torque arms (90), a first arm end (102) of one each of
said torque arms (90) non-pivotally supporting one each of said
torsion tubes (34); and an actuator (40) pivotally supporting a
second arm end (104) of said each of said torque arms (90) and in
communication with said rod member (96) such that extension of said
rod member (96) from said body (92) moves said actuator (40) to
enable rotation of said torsion tubes (34), via said torque arms
(90).
7. A structure (26) as claimed in claim 6 wherein a first end (134)
of said rod member (96) pivotally couples to said body (34).
8. A structure (26) as claimed in claim 7 wherein a second end
(136) of said rod member (96) pivotally couples to said actuator
(40).
9. A structure (26) as claimed in claim 6 wherein: said actuator
(40) comprises a plurality of eye sections (130); and said second
arm end (104) of said each of said torque arms (90) comprises a pin
member (128), said pin member (128) interfacing with one of said
plurality of eye sections (130).
10. A structure (26) as claimed in claim 6 wherein said actuator
(40) is in substantially parallel alignment with said elongated
rigid member (68).
11. A structure (26) as claimed in claim 6 wherein said elongated
rigid member (68) is positioned proximate said actuator (40).
12. A structure (26) as claimed in claim 6 wherein said actuator
(40) is a non-articulating element.
13. A structure (26) as claimed in claim 6 wherein said surface
(28) is a foundation (94) and said structure (26) further comprises
a support section (98) coupled to a first end of said elongated
rigid member (68), said support section (98) and said body (92) of
said drive mechanism (38) being coupled to said foundation
(94).
14. A structure (26) as claimed in claim 13 wherein a first one of
said posts (50) is coupled to a top of said support section (98),
and a first one of said torsion tubes (34) is retained by said
first one of said posts.
15. A structure (26) as claimed in claim 13 wherein said support
section (98) includes a pivot section for pivotal attachment of
said rod member (96).
16. A structure (26) as claimed in claim 13 wherein said first base
(46) is located proximate a second end of said elongated rigid
member (68).
17. A structure (26) as claimed in claim 1 wherein said energy
conversion modules (24) are flat, rectangular solar panels, and
said torsion tubes (34) are north-south oriented to define a
north-south axis (36).
18. A structure (26) for supporting an array (22) of energy
conversion modules (24) above a surface (28) comprising: a ganged
pier (44) comprising an elongated rigid member (68) and posts (50)
upwardly extending from said rigid member (68); torsion tubes (34),
one each of said torsion tubes (34) being pivotally retained by one
each of said posts (50) to form parallel rows (32) of said torsion
tubes (34), said torsion tubes (34) being configured for attachment
of said energy conversion modules (24) to form said array (22); an
actuator (148) having a body (150) and a rod (152) extendible from
said body (150), one of said body (150) and said rod (152) being
attached to said ganged pier (44); torque arms (90), a first arm
end (102) of one each of said torque arms (90) non-pivotally
supporting one each of said torsion tubes (34); and a linkage
member (144) pivotally supporting a second arm end (104) of said
each of said torque arms (90), said linkage member (144) being in
communication with another of said body (150) and said rod (152) to
enable rotation of said torsion tubes (34) and said energy
conversion modules (24) via said torque arms (90).
19. A structure (26) as claimed in claim 18 wherein said ganged
pier (44) further includes a lower post (46) downwardly extending
from said rigid member (68) and attached to a footing (48) formed
in said surface (28), and said one of said body (150) and said rod
(152) is attached to said ganged pier (44) proximate said lower
post (46).
20. A structure (26) as claimed in claim 18 wherein said elongated
rigid member (68) comprises a truss.
21. A structure (26) as claimed in claim 18 further comprising a
pivot element (154) pivotally attaching said one of said body (150)
and said rod (152) to said ganged pier (44).
22. A structure (26) as claimed in claim 18 further comprising a
pivot element (156) for pivotal communication between said another
of said body (150) and said rod (152) and said linkage member
(144).
23. A structure (26) as claimed in claim 18 wherein said linkage
member (144) is longitudinally aligned with said elongated rigid
member (68) of said ganged pier (44).
24. A structure (26) as claimed in claim 18 wherein said linkage
member (144) is a non-articulating element.
25. A structure (26) as claimed in claim 18 further comprising: a
second ganged pier (44) comprising a second elongated rigid member
(68) having a second end coupled with a first end of said rigid
member (68) and second posts (50) upwardly extending from said
second rigid member (68); second torsion tubes (34), one each of
said second torsion tubes (34) being pivotally retained by one each
of said second posts (50) to form additional parallel rows (32) of
said second torsion tubes (34) that are substantially parallel to
said first torsion tubes (34), additional ones of said energy
conversion modules (24) being attached to said second torsion tubes
(34); a second actuator (148) having a second body (150) and a
second rod (152) extendible from said second body (150), one of
said second body (150) and said second rod (152) being attached to
said second ganged pier (44); second torque arms (90), a third arm
end of one each of said second torque arms (90) non-pivotally
supporting one each of said second torsion tubes (34); and a second
linkage member (144) pivotally supporting a fourth arm end of said
each of said second torque arms (34), said second linkage member
(144) being in communication with another of said second body (150)
and said second rod (152) to enable rotation of said second torsion
tubes (34) and said additional energy conversion modules (24) via
said second torque anus (90).
26. A structure (26) as claimed in claim 25 further comprising a
controller (158) in communication with each of said first and
second actuators (148), said controller (158) managing extension of
said first and second rods (152) to enable concurrent rotation of
said first and second torsion tubes (34).
27. A solar energy collection system (20) comprising: an array (22)
of flat, rectangular solar panels (24); and a structure (26) for
supporting said array (22) of solar panels (24) above a surface
(28), said structure (26) comprising: an elongated rigid member
(68); a base (46) coupled to a bottom edge (70) of said rigid
member (68) for attachment to said surface (28); a first base (46)
supporting said rigid member (68); a second base (46) spaced apart
from said first base (46) and supporting said rigid member (68),
said first and second bases (46) being configured for attachment to
said surface (28); posts (50) extending from a top edge (72) of
said rigid member (68); and torsion tubes (34), one each of said
torsion tubes (34) being pivotally retained by one each of said
posts (50) to form parallel rows (32) of said torsion tubes (34),
said torsion tubes (34) being north-south oriented to define a
north-south axis (36), and said solar panels (24) being attached to
said torsion tubes (34) to form said array (22).
28. A solar energy collection system (20) as claimed in claim 27
wherein said elongated rigid member (68) comprises a truss.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of solar energy
collection systems. More specifically, the present invention
relates to a structure for supporting an array of solar energy
conversion modules.
BACKGROUND ART
[0002] Due to the finite supply of fossil energy sources, the
global environmental damage caused by fossil fuels, increasing
energy demand, and economic forces, society is becoming compelled
to diversify energy resources. One such technology that has
received significant attention is the use of solar energy.
[0003] Solar energy collection systems are used for a variety of
purposes, for example, as utility interactive power systems, power
supplies for remote or unmanned sites, and cellular phone
switch-site power supplies. An array of energy conversion modules,
such as, photovoltaic (PV) modules, in a solar energy collection
system can have a capacity from a few kilowatts to a hundred
kilowatts or more, depending upon the number of PV modules, also
known as solar panels, used to form the array. The solar panels can
be installed wherever there is exposure to the sun for significant
portions of the day.
[0004] In general terms, a solar energy collection system includes
an array of solar panels arranged in the form of rows and mounted
on a support structure. The solar panels are oriented to optimize
the solar panel energy output to suit the particular solar energy
collection system design requirements. Solar panels may be mounted
on a fixed structure, with a fixed orientation and fixed tilt, or
may be mounted on a tracking structure that aims the solar panels
toward the sun as the sun moves across the sky during the day and
as the sun path moves in the sly during the year. Tracking the sun
can lead to a significant increase in annual radiation falling on
the tracked surface, thus an increase in efficiency, relative to a
fixed structure.
[0005] Significant technological progress has been achieved in the
design and production of solar panels, accompanied by increased
efficiency and reductions in manufacturing cost. Another a major
cost element involved in the establishment of a wide-scale solar
energy collection system is the cost of the support structure used
to mount the solar panels of the array in proper position for
receiving and converting solar energy.
[0006] Many different support structures for solar panels have been
proposed and implemented. Unfortunately, many of these support
structures are so costly and mechanically complicated that they
have hindered the widespread introduction of solar arrays for the
generation of commercial and industrial electricity. In addition to
the mechanical complexity of such support structures, costs are
also largely influenced by the number and size of the footings to
which the support structure is fastened. The cost of footings is
governed by labor costs, soil conditions, and site preparation
costs, as well as the cost and availability of concrete.
[0007] A shortage of cement, the basic ingredient for concrete, has
been exacerbated by a continued housing boom and import
constraints, and has resulted in significant increases in the cost
of cement. The shortage of cement afflicts many regions, and is
particularly problematic in the United States across the sunbelt,
from Florida to California. Of course, the sunbelt is likely to
also be the desired location for large solar energy collection
systems due to the abundant sunshine.
[0008] As a result of the cost and mechanical complexity of
existing solar energy collection systems, and the costs associated
with constructing the footings to which the support structure is
fastened, there has been an unwillingness to proceed with
wide-scale solar energy collection systems, despite their obvious
advantages in terms of desired environmental effects and
conservation of fossil energy sources.
DISCLOSURE OF INVENTION
[0009] Accordingly, it is an advantage of the present invention
that a structure for supporting energy conversion modules is
provided.
[0010] It is another advantage of the present invention that a
structure for supporting energy conversion modules is provided
having a stable geometry that reduces the number of concrete
footings.
[0011] Another advantage of the present invention is that a
structure is provided for supporting energy conversion modules that
is mechanically straightforward.
[0012] Yet another advantage of the present invention is that a
structure is provided that is stable in wind and other weather
phenomena.
[0013] The above and other advantages of the present invention are
carried out in one form by a structure for supporting an array of
energy conversion modules above a surface. The structure includes
an elongated rigid member, a base coupled to a bottom edge of the
rigid member for attachment to the surface, and posts extending
from a top edge of the rigid member. The structure further includes
torsion tubes, one each of the torsion tubes being pivotally
retained by one each of the posts to form parallel rows of the
torsion tubes. The torsion tubes are configured for attachment of
the energy conversion modules to form the array.
[0014] The above and other advantages of the present invention are
carried out in another form by a solar energy collection system.
The system includes an array of flat, rectangular solar panels and
a structure for supporting the solar panels above a surface. The
structure includes an elongated rigid member, a base coupled to a
bottom edge of the rigid member for attachment to the surface, and
posts extending from a top edge of the rigid member. The structure
further includes torsion tubes, one each of the torsion tubes being
pivotally retained by one each of the posts to form parallel rows
of torsion tubes. The torsion tubes are north-south oriented to
define a north-south axis, and the solar panels are attached to the
torsion tubes to form the array.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] A more complete understanding of the present invention may
be derived by referring to the detailed description and claims when
considered in connection with the Figures, wherein like reference
numbers refer to similar items throughout the Figures, and:
[0016] FIG. 1 shows a perspective view of a solar energy collection
system for collecting solar energy in accordance with a preferred
embodiment of the present invention;
[0017] FIG. 2 shows a perspective view of the solar energy
collection system with solar panels removed for visualizing the
underlying components of the system;
[0018] FIG. 3 shows a perspective view of the solar energy
collection system with torsion tubes and an actuator removed for
visualizing an underlying support structure;
[0019] FIG. 4 shows an exploded perspective view of a rigid
subassembly utilized to form one of the support assemblies of FIG.
3;
[0020] FIG. 5 shows a side view of the rigid subassembly of FIG.
4;
[0021] FIG. 6 shows an exploded partial perspective view of
connectors used to couple a pair of trusses to form the support
assemblies of FIG. 3;
[0022] FIG. 7 shows a partial perspective view of a junction
between a pair of trusses of a rigid subassembly coupled utilizing
the connectors of FIG. 6;
[0023] FIG. 8 shows a side schematic view of one of the support
assemblies that includes five of the rigid subassemblies of FIG.
4;
[0024] FIG. 9 shows a partial perspective view of the solar energy
collection system of FIG. 1 including a drive mechanism, an
actuator, and torque arms for enabling rotation of torsion tubes of
the system;
[0025] FIG. 10 shows a perspective view of a support section of the
solar energy collection system;
[0026] FIG. 11 shows a perspective view of a flexible connection
between an actuator and a torque arm of the solar energy collection
system;
[0027] FIG. 12 shows a partial side schematic view of a drive
mechanism interconnected with the actuator and a number of torque
arms of the solar energy collection system;
[0028] FIG. 13 shows a partial side view of a support assembly for
the solar energy collection system that includes multiple drive
mechanisms in accordance with an alternative embodiment of the
present invention; and
[0029] FIG. 14 shows an enlarged partial perspective view of the
support assembly of FIG. 13 illustrating one of the drive
mechanisms.
BEST MODES FOR CARRYING OUT THE INVENTION
[0030] FIG. 1 shows a perspective view of a solar energy collection
system 20 for collecting solar energy in accordance with a
preferred embodiment of the present invention. Solar energy
collection system 20 is a single-axis solar tracking system. A
single-axis tracking system represents a reasonable compromise
between fixed, non-tracking, systems and multiple-axis tracking
systems. That is, a single-axis tracking system achieves the
benefit of an increase in efficiency over a fixed system without
the undesirable complexity and cost of a multiple-axis tracking
system.
[0031] System 20 generally includes an array 22 of flat,
rectangular energy conversion modules 24 and an underlying support
structure 26 for supporting array 22 above a surface 28 of the
earth. System 20 moves array 22 of energy conversion modules 24
around a single axis, and therefore approximates tracking of the
actual position of the sun.
[0032] Each of energy conversion modules 24 incorporates at least
one device, e.g., a photovolataic and/or thermovoltaic cell or a
solar panel made using such cells, configured to convert solar
energy into electrical energy. For the remainder of this document,
energy conversion modules 24 are referred to herein as solar panels
24. However, the use of alternative energy conversion modules 24
does not depart from the spirit of the present invention.
[0033] Solar panels 24 are arranged in rows 32, and are supported
by torsion tubes 34. In an exemplary embodiment, solar panels 24
are roughly 150 W solar panels that are approximately four feet
long. System 20 includes multiple rows 32, in this exemplary case,
twenty-one rows 32 of thirty-four solar panels each. Consequently,
such a system may be capable of producing over one hundred
kilowatts of electricity, thereby making it suitable for commercial
and/or industrial applications. However, the present invention is
not limited to the specific configuration of solar panels presented
herein, but may instead be scaled to accommodate other size panels
and/or different quantities of rows 32 and solar panels 24.
[0034] Torsion tubes 34 are generally north-south oriented to
roughly define a north-south axis 36. However, nothing requires
high precision in this orientation. A drive mechanism 38 gradually
rotates rows 32 of solar panels 24 throughout the day from an
east-facing direction in the morning to a west-facing direction in
the afternoon. Rows 32 of solar panels 24 are subsequently brought
back to the east-facing orientation for the next day. Although a
north-south orientation of torsion tubes 34 is shown, such is not a
limitation of the present invention. Alternatively, the present
invention may incorporate a seasonal orientation in which torsion
tubes 34 are roughly arranged in an east-west orientation and solar
panels 24 are rocked in a north-south direction to accommodate
seasonal movement of the sun.
[0035] System 20 desirably rotates around an axis that is generally
horizontal. However, that is not a limitation of the present
invention. Alternatively, system 20 may be adapted to rotate around
an axis that is tilted on an angle relative to horizontal that
corresponds to the latitude of the location. A tilted single-axis
tracking structure generally achieves a performance that is
improved relative to horizontal single-axis tracking structures
because it places the array of solar panels on average closer to
perpendicular relative to the path of the sun.
[0036] Referring to FIG. 2 in connection with FIG. 1, FIG. 2 shows
a perspective view of solar energy collection system 20 with solar
panels 24 removed for visualizing the underlying components of
system 20. With solar panels 24 removed, support structure 26,
torsion tubes 34, and drive mechanism 38 are visible. Drive
mechanism 38 is in communication with an actuator 40, and actuator
40 is in communication with torsion tubes 34. Consequently,
actuation of drive mechanism 38 enables rotation of torsion tubes
34 via actuator 40 to rotate rows 32 of solar panels 24 from an
east-facing direction in the morning to a west-facing direction in
the afternoon.
[0037] Now referring to FIG. 3 in connection with FIGS. 1-2, FIG. 3
shows a perspective view of solar energy collection system 20 with
torsion tubes 34 and actuator 40 removed for visualizing support
structure 26. Support structure 26 includes one or more support
assemblies 42. In the exemplary embodiment of FIGS. 1-3, system 20
includes three support assemblies 42 in substantially parallel
spaced-apart alignment.
[0038] Each of support assemblies 42 includes a number of
interconnected, rigid subassemblies 44. Each of rigid subassemblies
44 includes a single base 46 (see FIG. 4) that is fastened to a
concrete footing 48, and each of rigid subassemblies 44 includes a
number of posts 50 to which torsion tubes 34 are coupled. As shown,
each subassembly 44 carries four posts 50, each of which pivotally
retains one of torsion tubes 34. Thus, one footing 48 is utilized
for every four posts 50. This configuration directly contrasts with
prior art systems in which separate footings are utilized for each
of the posts.
[0039] Through the utilization of multiple support assemblies 42 of
rigid subassemblies 44, a support structure 26 is provided that is
stable in wind. This stability is achieved despite a reduction in
quantity of footings 48 relative to prior art configurations.
Moreover, rigid subassemblies 44 can be manufactured offsite,
rather than at the intended location of system 20, and support
assemblies 42 can subsequently be assembled at the intended
location of system 20. Consequently, the use of support structure
26 simplifies the construction of system 20 and achieves
significant savings in terms of the use of pre-manufactured
subassemblies, labor, site preparation, and concrete costs.
Although rigid subassemblies 44 are described herein as including
four posts 50, this is not a limitation of the present invention.
Rather, rigid subassemblies 44 can be adapted to include other
quantities of multiple posts 50.
[0040] Support structure 26 further includes one or more rigid
supports 52 (e.g., stiff rod members) coupled to the top of each of
rigid subassemblies 44 and extending away from a longitudinal axis
54 of rigid subassemblies 44. A distal end 56 of each of rigid
supports 52 is fixed to a footing 58 in surface 28. Rigid supports
52 limit bowing, or flexure, in the north-south direction, and
provides support for resistance to transverse overturning, or
wobbling. As shown, rigid supports 52 associated with rigid
subassemblies 44 of two adjacent support assemblies 42 may
optionally attach to the same footings 58 for economy.
[0041] Posts 50 of each of support assemblies 42 are in parallel
alignment with one another. That is, posts 50 of a first support
assembly 42a, a second support assembly 42b, and a third support
assembly 42c are aligned in rows 32 such that three aligned posts
50 pivotally retain one of torsion tubes 34 (FIG. 2).
[0042] In a preferred embodiment, each generally horizontal column
60 of support structure 26 is arranged substantially perpendicular
to the generally horizontal rows 32 of torsion tubes 34 (FIG. 2),
and includes one of support assemblies 42. However, as illustrated
in FIG. 3, solar energy collection system 20 may optionally have
one or more columns 60 of posts 64 set in individual concrete
footings 66 and spaced-apart from support assemblies 42. Outer
columns 60 of posts 64 set in individual concrete footings 66 may
alternatively be employed to allow easier human access to solar
panels 24 as needed. Posts 64 are accordingly aligned with posts 50
in each of rows 32, and pivotally retain torsion tubes 34 (FIG.
2).
[0043] Referring to FIGS. 4-5, FIG. 4 shows an exploded perspective
view of a one of rigid subassemblies 44 utilized to form one of
support assemblies 42 (FIG. 3), and FIG. 5 shows a side view of
rigid subassembly 44. As mentioned above, a number of rigid
subassemblies 44 are assembled to form one of support assemblies
42. Accordingly, the following discussion applies equally to all
rigid subassemblies 44 that make up each of support assemblies
42.
[0044] Rigid subassembly 44 includes an elongated rigid member 68
and base 46 coupled to a bottom edge 70 of rigid member 68 for
attachment to one of footings 48. Posts 50 extend from a top edge
72 of rigid member 68. Each of posts 50 pivotally retains one of
torsion tubes 34, of which only one is shown in partial form. The
retaining element of each of posts 50 may be in the form of a
ring-shaped collar 74 that loosely retains one of torsion tubes 34,
thereby allowing it to pivot in response to actuation via drive
mechanism 38 (FIG. 1), discussed below.
[0045] In a preferred embodiment, elongated rigid member 68 is a
truss, i.e., a framework of straight slender struts connected at
joints. Elongated rigid member 68, referred to hereinafter as truss
68, is a simple span with each member designed to carry a tension
or compression force. Thus, truss 68 acts like a beam to support
multiple torsion tubes 34 on posts 50, and multiple solar panels 24
(FIG. 1). Truss 68 is utilized in a preferred embodiment because it
is economically manufactured by multiple commercial vendors and can
be readily procured for use within solar energy collection system
20 (FIG. 1). However, those skilled in the art will recognize that
other girder structures, such as an I-beam, may alternatively be
employed for supporting torsion tubes 34 on posts 50, and solar
panels 24.
[0046] Rigid subassembly 44 further includes a rigid support 76
that extends from top edge 72 of truss 68 and couples to an outer
edge 78 of base 46. Like rigid supports 52, rigid support 76
provides additional support for resistance to transverse
overturning, or wobbling, when subassembly 44 is under load.
Although support structure 26 is shown as having both rigid
supports 52 (FIG. 3) and rigid support 76, support structure 26 may
alternatively include either rigid supports 52 or rigid support 76.
Furthermore, subassembly 44 may be sufficiently rigid so that
neither rigid supports 52 nor rigid support 76 are necessary for
providing resistance to transverse overturning.
[0047] Rigid subassembly 44 further includes connectors 80 that
form the connection between pairs of rigid subassemblies 44 of
support assemblies 42 (FIG. 3). Multiple rigid subassemblies 44 may
be connected serially to allow additional rows 32 (FIG. 1) of solar
panels 24 to be supported by system 20 (FIG. 1).
[0048] Referring to FIGS. 6-7, FIG. 6 shows an exploded partial
perspective view of connectors 80 used to couple a pair of trusses,
i.e. a first truss 68a and a second truss 68b, to form one of
support assemblies 42 (FIG. 3). FIG. 7 shows a partial perspective
view of a junction 82 between a first end 84 of first truss 68a and
a second end 86 of second truss 68b utilizing connectors 80.
[0049] Base 46 (FIG. 4) is not shown in FIGS. 6-7 for simplicity of
illustration. However, it should be understood that base 46 will be
coupled to bottom edge 70 of one of first and second trusses 68a
and 68b proximate junction 82. Similarly, one of posts 50 (FIG. 4)
coupled to top edge 72 of one of first and second trusses 68a and
68b, and generally vertically aligned with base 46, is not shown in
FIGS. 6-7 for simplicity of illustration.
[0050] In an exemplary embodiment, each of connectors 80 is formed
of angle iron, i.e., a metal strip of iron or steel bent to form a
right angle. Connectors 80 are fixedly coupled to one of first and
second trusses 68a and 68b, respectively, and are slidably coupled
to the other of first and second trusses 68a and 68b. By way of
example, each of four connectors 80 is welded to first end 84 of
first truss 68a, and each of connectors 80 overlaps and slides
along second end 86 of second truss 68b. This slideable coupling of
connectors 80 between first and second trusses 68a and 68b,
respectively, at junction 82 serves to accommodate thermal
expansion, i.e., any increase in dimensions of first and second
trusses 68a and 68b as a result of an increase in temperature while
preventing vertical movement. Utilizing four connectors 80 and
positioning them on four opposing corners of first and second ends
84 and 86 of respective first and second trusses 68a and 68b
ensures that first and second trusses 68a and 68b are retained
parallel and in serial alignment relative to one another despite
thermal expansion induced movement.
[0051] Connectors 80 manufactured from angle iron are
advantageously utilized due to their ready availability,
simplicity, and low cost. However, the use of angle iron for the
use of connectors 80 is not a limitation. Those skilled in the art
will recognize that alternative connectors may be employed in which
one portion of the connector is fixed to one of first and second
trusses 68a and 68b, respectively, and another portion of the
connector is allowed to slide relative to the other of first and
second trusses 68a and 68b in response to thermal expansion.
[0052] FIG. 8 shows a side schematic view of one of support
assemblies 42 that includes five interconnected rigid subassemblies
44. A pair of bases 46 (i.e., base 46 of a first one of
subassemblies 44 and a second base 46 of an adjacent one of
subassemblies 44, that is spaced apart from base 46 of the first
subassembly 44) support one of trusses 68, for example, first truss
68a (FIG. 6). Thus the term "support" encompasses a physical
coupling, or attachment, as well as via the slidable coupling of
first and second trusses, 68a and 68b, respectively (FIG. 6), as
discussed above.
[0053] In addition, since each of subassemblies 44 includes only
one base 46, an additional base 88 should be coupled to bottom edge
70 of an endmost one of subassemblies 44. Alternatively, a support
section (described in connection with FIG. 9) may be coupled to an
end of second support assembly 42b (FIG. 3) in lieu of additional
base 88. A junction formed between the endmost one of subassemblies
44 and base 88 or the alternative support section desirably
includes a slidable coupling, such as connectors 80 described
above, to accommodate thermal expansion.
[0054] Each of rigid subassemblies 44 includes four posts 50 for
pivotally retaining torsion tubes 34 (FIG. 2). Consequently,
interconnection of multiple rigid subassemblies 44 enables the
formation of additional rows 32 (FIG. 2) of torsion tubes 34 all of
which are substantially parallel to one another.
[0055] FIG. 9 shows a partial perspective view of solar energy
collection system 20 including drive mechanism 38, actuator 40, and
torque arms 90 for enabling rotation of torsion tubes 34. FIG. 9
further shows actuator 40 positioned proximate second support
assembly 42b, of which only a portion is shown, and oriented
generally parallel to second support assembly 42b.
[0056] Drive mechanism 38 includes a body 92 configured for
attachment to a foundation 94 and a rod member 96 extendible from
body 92. A support section 98 is also configured for attachment to
foundation 94. Support section 98 includes a pair of posts 100,
each of which has ring-shaped collar 74 coupled thereto for
pivotally retaining one of torsion tubes 34. Posts 100 establish a
first one of rows 32 of array 22 (FIG. 1), and are aligned with
posts 50 and posts 64 of other columns 60 of support structure 26,
as described in connection with FIG. 3. Support section 98
additionally provides an attachment point for a first one of rigid
subassemblies 44 of second support assembly 42b.
[0057] Each of torque arms 90 includes a first arm end 102 that
non-pivotally supports one of torsion tubes 34. More specifically,
first arm end 102 of each of torque arms 90 is in fixed engagement
with one of torsion tubes 34. In contrast, actuator 40 pivotally
supports a second arm end 104 of each of torque anus 90. That is,
each of torque arms 90 is enabled to pivot about a flexible
connection 106, such as a pivot, hinge, or the like, formed between
actuator 40 and second arm end 104. The term "supports" utilized
herein refers to a feature of the present invention in which torque
arms 90 are in communication with, or coupled to, torsion tubes 34
and actuator 40. Those skilled in the art will understand that this
coupling can be implemented by various known techniques.
[0058] Actuator 40 is in communication with rod member 96 such that
extension or retraction of rod member 96 relative to body 92 moves
actuator 40 to enable rotation of each of torsion tubes 34 via
torque arms 90. More specifically, collars 74 of posts 50 (only one
of which is visible) and collars 74 of posts 100 pivotally retain
torsion tubes 34, but torsion tubes 34 do not pivot relative to
first arm end 102 of torque arms 90. Consequently, forward/backward
linear movement of actuator 40, as represented by a bi-directional
arrow 108, yields corresponding pivotal, or rotational, movement of
torsion tubes 34, as represented by an arrow 110. Since solar
panels 24 (FIG. 1) are fixedly coupled to torsion tubes 34,
pivoting movement 110 of torsion tubes 34 rotates rows 32 of solar
panels 24.
[0059] Drive mechanism 38 drives array 22 (FIG. 1) of solar panels
24 by a single generally horizontal linear actuator 40. A variety
of mechanisms may be employed to form drive mechanism 38, such as
hydraulic cylinder, a screw-type mechanism, and so forth. This
single drive mechanism 38 is thus capable of moving all rows 32
(FIG. 1) of array 22 from an east-facing direction in the morning
to a west-facing direction in the afternoon. In the embodiment
described above, drive mechanism 38 is desirably capable of
applying more than 50,000 pounds of force to move and/or hold array
22 in windy conditions. However, drive mechanism 38 may be
alternatively configured to apply an appropriate amount of force in
accordance with the particular size and configuration of a
different array of solar panels. Drive mechanism 38 may be actuated
by a timer that causes rod member 96 to extend or retract in
response to the time of day. Alternatively, drive mechanism 38 may
be in communication with a light sensor which actuates drive
mechanism 38 in response to the direction of the sunlight.
[0060] FIG. 10 shows a perspective view of support section 98 of
solar energy collection system 20 (FIG. 1). As discussed briefly
above, support section 98 attaches to foundation 94 (FIG. 9).
Support section 98 includes a pair of base members 112 upon which
posts 100 are affixed. Braces 114 provide additional support for
posts 100. In an exemplary embodiment, posts 100 are generally
rectangular in cross-section for ready attachment of one of rigid
subassemblies 44 (FIG. 4), although such a shape is not a
limitation of the present invention. A first pivot axis 116 is
positioned at ring-shaped collars 74 mounted on posts 100. First
pivot axis 116 represents pivotal movement 110 of torsion tubes 34
(FIG. 9).
[0061] Support section 98 further includes an eye section 118
mounted on each of base members 112. Eye section 118 pivotally
supports rod member 96 (FIG. 9), thereby enabling pivotal coupling
between rod member 96 and body 92 (FIG. 9) of drive mechanism 38
(FIG. 9) about a second pivot axis 126. Thus, rod member 96 is
pivotally retained between braces 114. As rod member 96 extends
from or retracts toward body 92, rod member 96 is allowed to pivot
about second pivot axis 126 to accommodate vertical movement of
actuator 40 (discussed below).
[0062] FIG. 11 shows a perspective view of flexible connection 106
between actuator 40 and second arm end 104 of one of torque arms 90
of solar energy collection system 20 (FIG. 1). FIG. 11 illustrates
only one flexible connection 106. However, the following discussion
applies equally to each of flexible connections 106 between
actuator 40 and each of torque arms 90. In a preferred embodiment,
second arm end 104 of each of torque arms 90 includes a pin member
128. Actuator 40 includes a plurality of eye sections 130. Flexible
connection 106 is established by directing pin member 128 through
eye section 130. Pin member 128 is preferably pivotally retained in
eye section 130 utilizing a fastener (not shown) such as a cap nut,
a cotter pin, and the like known to those skilled in the art. The
pivoting retention of pin member 128 in eye section 130 yields a
robust flexible connection 106 about a third pivot axis 132 for
translating linear movement 108 of actuator 40 to pivotal movement
of torsion tubes 34 (FIG. 1).
[0063] FIG. 12 shows a partial side schematic view of drive
mechanism 38 interconnected with actuator 40 and a number of torque
arms 90 of solar energy collection system 20. In a preferred
embodiment, actuator 40 is a non-articulating element. More
specifically, actuator 40 may be a single elongated member or a
series of linked members that are not allowed to articulate
relative to one another so that actuator is rigid along its entire
length. This rigid configuration of actuator 40 resists binding as
actuator 40 moves, as opposed to prior art articulated systems.
[0064] As further shown in FIG. 12, a proximal end 134 of rod
member 96 pivotally couples to body 92 at eye section 118 of
support section 98. In addition, a distal end 136 of rod member 96
pivotally couples to each of actuator 90, and an actuator end 138
of actuator 40 at a first one of eye sections 130 on actuator 40
via an associated one of pin members 128. Thus, rod member 96 is
further able to pivot relative to actuator 40. Pivoting action of
rod member 96 at second pivot axis 126 and third pivot axis 132
allows vertical adjustment of rod member 96, while maintaining
actuator 40 in a generally horizontal orientation relative to
surface 28.
[0065] Referring to FIGS. 13-14, FIG. 13 shows a partial side view
of a support assembly 140 for solar energy collection system 20
that includes multiple drive mechanisms 142 in accordance with an
alternative embodiment of the present invention. FIG. 14 shows an
enlarged partial perspective view of support assembly 140
illustrating one of drive mechanisms 142. Support assembly 140
including drive mechanisms 142 may be utilized in lieu of support
assemblies 42 (FIG. 3) and drive mechanism 38 (FIG. 1) to further
reduce the cost and mechanical complexity of solar energy
collection system 20.
[0066] Support assembly 140 can be utilized to support array 22
(FIG. 1) of energy conversion modules, or solar panels 24. It
should be noted however that support structure 26 (FIG. 2) for
solar energy collection system 20 utilizing support assembly 140
need not have a configuration of five columns 60 (FIG. 3). Rather,
such a support structure may instead have a configuration that
includes a single central column 60 having support assembly 140 and
any remaining columns 60 having individual concrete piers, or
footings 66 (FIG. 3).
[0067] Support assembly 140 includes a number of interconnected,
rigid subassemblies 44 and torsion tubes 34. Each of rigid
subassemblies 44 serves as a pier, i.e., a generally vertical
structural support, for a number of torsion tubes 34. Accordingly,
rigid subassemblies 44 are referred to hereinafter as ganged piers
44. Only two interconnected ganged piers 44 are shown for
simplicity of illustration. However, solar energy collection system
20 utilizing support assembly 140 can employ more or less than two
of ganged piers 44. The following discussion applies equally to
each of ganged piers 44. Accordingly, ganged piers 44 and their
components will be discussed below in their singular form for
simplicity.
[0068] As discussed in detail in connection with FIGS. 4-9 above,
ganged pier 44 includes elongated rigid member 68, in the form of a
truss. Base 46, in the form of a downwardly extending post 46,
extends below rigid member 68. Downwardly extending post 46 is
fastened to concrete footing 48. Ganged pier 44 further includes
posts 50 upwardly extending from rigid member 68. Ganged pier 44
carries four upwardly extending posts 50, each of which pivotally
retains one of torsion tubes 34.
[0069] Support assembly 140 includes torque arms 90, one each of
torque arms 90 being associated with one each of torsion tubes 34.
In this exemplary configuration, four torque arms 90 are associated
with each of the four torsion tubes 34 carried by each ganged pier
44. First end 102 of torque arm 90 non-pivotally supports one of
torsion tubes 34, as previously discussed. Second end 104 of torque
arm 90 extends away from its corresponding one of torsion tubes 34
in a direction substantially perpendicular to the plane formed by
solar panels 44 for row 32 (FIG. 1).
[0070] Support assembly 140 further includes a number of linkage
actuators, in the form of rigid elongated linkage members 144, and
drive mechanisms 142. In a preferred embodiment, each ganged pier
44 has its own one of linkage members 144 and drive mechanisms 142.
Thus, linkage members 144 and drive mechanisms 142 are described in
singular form in connection with ganged pier 44. However, the
following discussion applies equally to all linkage members 144 and
drive mechanisms 142 of support assembly 140.
[0071] Each linkage member 144 may be a single elongated member or
a series of linked sections that are not allowed to articulate
relative to one another so that linkage member 144 is rigid along
its entire length. This rigid configuration of linkage member 144
resists binding as linkage member 144 moves. Linkage member 144
pivotally supports second end 104 of each of torque arms 90
associated with ganged pier 44. For example, a first pivot element
146, such as a pintle mechanism, may rotatably couple linkage
member 144 and torque arms 90 associated with ganged pier 44.
[0072] Drive mechanism 142 includes a linear actuator 148 having a
body 150 and a rod 152 extendible from body 150. Body 150 is
attached to ganged pier 44, preferably proximate to downwardly
extending post 46. A second pivot element 154 pivotally attaches
body 150 to ganged pier 44. Rod 152 is in communication with
linkage member 144. More specifically, rod 152 couples to linkage
member 144 through an under-hanging projection, in the form of a
third pivot element 156. A variety of mechanisms may be employed to
form linear actuators 148, such as a hydraulic cylinder, a
screw-type mechanism, and so forth, known to those skilled in the
art.
[0073] A controller, i.e., a control source 158, is in
communication with each of linear actuators 148 of support assembly
140. Control source 158 manages concurrent extension and retraction
of rod 152 of each of actuators 146. Thus, as control source 158
causes each rod 152 of each of actuators 146 to extend and retract,
each of linkage members 144 moves in a corresponding east-west
direction. Movement of linkage members 144 causes the associated
torque arms 90, torsion tubes 34 and solar panels 24 to rotate in
unison. Pivoting action at first, second, and third pivot elements
146, 154, and 156 permits vertical adjustment of torque arms 90 and
actuator 144 relative to linkage member 144, while maintaining
linkage member 144 in a generally horizontal orientation relative
to surface 28 and longitudinally aligned with ganged pier 44.
[0074] The multiple linear actuators 148 are thus capable of moving
only those rows 32 (FIG. 1) of array 22 (FIG. 1) established by the
four torsion tubes 34 associated with one of ganged piers 44.
Through the implementation of multiple linear actuators 148 in
support assembly 140, each individual actuator 148 need apply
significantly less force to move and/or hold four rows 32 (FIG. 1)
of array 22 (FIG. 1) than the force needed for drive mechanism 38
to control all rows 32 of array 22. In addition, by having each of
actuators 144 mounted on their associated one of ganged piers 44, a
closed load loop is provided within ganged pier 44. Accordingly,
the loads that each of actuators 144 needs to accommodate are not
distributed to the earth, but are confined within ganged pier 44.
The lower load actuators 148 and the closed load loop within each
of ganged piers 44 eliminates the need for sizable, deep, and
expensive footings found in prior art systems. Furthermore, the
wide separation between footings 48 yields a more efficient
technique for managing overturning loads than in prior art systems.
Thus, costs associated with constructing footings, in terms of both
materials and labor, are significantly reduced while concurrently
yielding a stable structure.
[0075] In summary, the present invention teaches of a single axis
tracking structure for supporting energy conversion modules, such
as solar panels. The structure includes a number of spaced-apart
support assemblies that in turn include a number of interconnected
rigid truss subassemblies. This rigid structure yields a support
structure having a geometry that is stable in wind and other
weather phenomena. Moreover, the rigid structure enables a
reduction in the number and size of concrete footings to which the
structure is attached. A reduction in the number and size of
concrete footings significantly drives down the costs associated
with constructing the footings to which the support structure is
fastened. In addition, the actuator linkage and single drive
mechanism for concurrently pivoting all solar panels of an array is
mechanically straightforward, thereby reducing manufacturing,
assembly, and maintenance costs of the support structure. The
reduction in concrete requirements and the mechanical simplicity of
the support structure may greatly assist in the expansion of
wide-scale solar energy collection systems.
[0076] Although the preferred embodiments of the invention have
been illustrated and described in detail, it will be readily
apparent to those skilled in the art that various modifications may
be made therein without departing from the spirit of the invention
or from the scope of the appended claims. For example, the quantity
and size of the solar panels may vary from that which is shown,
thereby affecting the number and size of the support assemblies of
the support structure.
* * * * *