U.S. patent application number 12/389286 was filed with the patent office on 2010-08-19 for solar concentrator truss assemblies.
This patent application is currently assigned to John Danhakl. Invention is credited to Steve Thorne.
Application Number | 20100206303 12/389286 |
Document ID | / |
Family ID | 42558818 |
Filed Date | 2010-08-19 |
United States Patent
Application |
20100206303 |
Kind Code |
A1 |
Thorne; Steve |
August 19, 2010 |
Solar Concentrator Truss Assemblies
Abstract
Solar concentrator truss assemblies and arrays of solar
concentrator truss assemblies are disclosed. The solar concentrator
truss assembly has a V-shaped frame joined with a solar panel to
form a triangulated truss. The solar concentrator truss assembly is
lightweight and strong, and does not require extensive additional
structural support for installation. The array of solar
concentrator truss assemblies is motion controlled by a computer to
move the array into preferable positions with regards to
sunlight.
Inventors: |
Thorne; Steve; (Berkeley,
CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Danhakl; John
Pacific Palisades
CA
|
Family ID: |
42558818 |
Appl. No.: |
12/389286 |
Filed: |
February 19, 2009 |
Current U.S.
Class: |
126/696 |
Current CPC
Class: |
H02S 20/32 20141201;
Y02B 10/12 20130101; F24S 25/16 20180501; F24S 30/425 20180501;
F24S 25/15 20180501; H01L 31/0547 20141201; Y02E 10/47 20130101;
H02S 20/22 20141201; F24S 2030/136 20180501; Y02B 10/10 20130101;
F24S 23/77 20180501; Y02E 10/52 20130101; H02S 20/23 20141201 |
Class at
Publication: |
126/696 |
International
Class: |
F24J 2/10 20060101
F24J002/10 |
Claims
1. A solar concentrator truss assembly, comprising: a generally
V-shaped frame including an inner surface, the inner surface
including a first and second concentrating portion, the inner
surface including an unexposed portion located between the first
and second concentrating portion; and a solar panel including a
sun-facing surface and a bottom surface, the solar panel received
by the inner surface; wherein the solar panel bridges the inner
surface to form a truss with the generally V-shaped frame, such
that the sun-facing surface and the first and second reflective
portions are exposed to each other, and the bottom surface is
exposed to the unexposed portion.
2. The solar concentrator truss assembly of claim 1, wherein the
first and second concentrating portions are separated from one
another by an angle ranging from 60 to 90 degrees.
3. The solar concentrator truss assembly of claim 1, wherein the
first and second concentrating portions include reflective adhesive
films disposed thereon.
4. The solar concentrator truss assembly of claim 1, wherein the
generally V-shaped frame is constructed from a single piece of
sheet metal.
5. The solar concentrator truss assembly of claim 1, wherein the
inner surface includes shoulders complementary shaped to receive
the solar panel.
6. The solar concentrator truss assembly of claim 1, wherein the
solar panel is a stress bearing member.
7. The solar concentrator truss assembly of claim 1, wherein the
generally V-shaped frame additionally includes at least one
ventilation passage positioned below the bottom surface of the
solar panel.
8. The solar concentrator truss assembly of claim 1, wherein the
solar panel additionally includes an elongated axle extending past
the generally V-shaped frame.
9. The solar concentrator truss assembly of claim 1, wherein the
generally V-shaped frame includes an opening for a dowel socket in
the unexposed portion.
10. A solar concentrator array, comprising: a frame, including at
least one elongated beam; a plurality solar concentrator truss
assemblies, each solar concentrator assembly including: a generally
V-shaped frame including an inner surface, the inner surface
including a first and second concentrating portion, the inner
surface including an unexposed portion located between the first
and second concentrating portion, the generally V-shaped frame
including a socket; and a solar panel including a sun-facing
surface and a bottom surface, the solar panel bridging the inner
surface to form a truss with the generally V-shaped frame, such
that the sun-facing surface and the first and second reflective
portions are exposed to each other, the solar panel including an
elongated axle extending past the generally V-shaped frame and
rotatably coupled to the at least one elongated beam; and a motion
apparatus including a plurality of dowels, each respective dowel
moveably coupled to a respective socket of a respective generally
V-shaped frame for moving each respective solar concentrator truss
assembly around a respective axle.
11. The solar collector array of claim 10, wherein the frame
additionally includes a second elongated beam parallel to the at
least one elongated beam, wherein the axle of each respective solar
concentrator assembly is additionally rotatably coupled to the
second elongated beam.
12. The solar collector array of claim 10, wherein each generally
V-shaped frame is constructed from a single piece of sheet
metal.
13. The solar collector array of claim 10, wherein the first and
second concentrating portions are separated from each other by an
angle ranging from 60 to 90 degrees.
14. The solar collector array of claim 10, wherein the motion
apparatus additionally includes an elongated connecting rod coupled
to a linkage, and a motor moveably coupled to the linkage.
15. The solar collector array of claim 10, wherein the motion
apparatus additionally includes a motor moveably coupled to the
plurality of dowels, and a computer assembly operationally coupled
to the motor, the computer assembly configured to store and execute
instructions for controlling movement of the motor.
16. The solar collector array of claim 15, wherein the motion
apparatus additionally includes a directional light meter
operationally coupled to the computer assembly, the directional
light meter supplying a signal to the computer assembly, the signal
used to execute instructions for controlling movement of the
motor.
17. The solar collector array of claim 15, wherein the computer
assembly includes stored data, the stored data used to execute
instructions for controlling movement of the motor.
18. The solar collector array of claim 17, wherein the stored data
includes a location of the solar collector array, time, and
date.
19. The solar collector array of claim 10, additionally comprising
at least one inverter operationally coupled to the plurality solar
concentrator assemblies.
20. A solar concentrator truss assembly, comprising: a generally
V-shaped frame formed from a single piece of sheet metal, and
including a first planar member and a second planar member
separated by a 60 degree angle, the first planar member including:
a first inner surface, the first inner surface including a first
unexposed portion and a first concentrating portion, and a first
indented shoulder between the first unexposed portion and a first
concentrating portion, the second planar member including: a second
inner surface, the second inner surface including a second
unexposed portion and a second concentrating portion, and a second
indented shoulder between the second unexposed portion and a second
concentrating portion, the first and second inner surfaces being
exposed to each other; and a photovoltaic panel including a
sun-facing surface, a bottom surface, a first photovoltaic end, a
second photovoltaic end, and an elongated axle extending past the
generally V-shaped frame, the first photovoltaic end connected with
the first indented shoulder, the second photovoltaic end connected
with the second indented shoulder, the sun-facing surface being
exposed to the first and second reflective portions, the bottom
surface being exposed to the first and second unexposed portions,
wherein the first and second concentrating portions each include
reflective adhesive film, and wherein the photovoltaic panel is a
stress bearing member.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to devices and
systems for moveable solar panels. More particularly, the invention
relates to solar concentrator truss assemblies and arrays of
computer controlled solar concentrator truss assemblies.
[0002] A solar panel, such as a photovoltaic panel, apart from
lesser reflections, can only make use of direct light energy which
is incident to the surface of the solar panel. Thus, the amount of
light energy to be converted by the solar panel is limited to the
surface area of the solar panel. Solar concentrators, or
Concentrating Solar Photovoltaics (CPV), may be used to further
increase the amount of light energy received by a solar panel. A
solar concentrator is commonly a highly reflective surface, such as
a mirror, which is positioned to reflect light outside the area of
the solar panel to the surface of the solar panel. Thus, by using a
solar concentrator a solar panel can capture additional focused
light energy which would otherwise be unavailable. To take further
advantage of direct light energy, a solar panel and solar
concentrator may be moveable, and positioned such that the solar
panel is normal, i.e., perpendicular, to incoming light beams.
However, solar panels will typically capture over 96% of light
incident within 15 degrees of normal, thus, even a slight movement
of a solar panel may be of great use. Solar concentrator systems
are technologically divided by low, medium, and high concentration
ratios. Low concentration solar concentrator systems have a solar
concentration value in the range of 2-10 suns. For economic
reasons, conventional silicon solar cells are typically used, and,
at these concentrations, the heat flux is low enough that the cells
do not need to be actively cooled. A system with a low
concentration ratio can have a high acceptance angle and thus does
not require active solar tracking. Medium concentration solar
concentrator systems, with concentrations of 10 to 100 suns,
require solar tracking and cooling, which makes them more complex.
High concentration solar concentrator systems employ concentrating
optics consisting of dish reflectors or Fresnel lenses that
concentrate sunlight to intensities of 200 suns or more, which
require high-capacity heat sinks to prevent thermal destruction and
to manage temperature related performance losses.
[0003] Solar energy is an increasing popular form of energy use, as
light energy is freely obtained, and also produces no pollutants.
Many governments are also mandating laws which require the
reduction of pollution causing energy plants, further making solar
energy a viable option. However, costs of computer controlled
moveable solar panel systems can make implementation unviable. Most
solar panel systems are added to roofs of existing buildings, which
were not designed to support continuous loads other than the weight
of roofing material. Moveable solar panel systems are often
complex, and heavy, and thus require reinforcement of the building
structure for additional framing. Additionally, solar concentrators
are often not integral to existing solar panels, thus, adding more
installation and fabrication costs, weight, and complexity.
Accordingly, many people are dissuaded from installing solar panel
systems because the initial costs of installation are higher than
potential energy savings.
[0004] Therefore, a need remains for moveable solar panel
assemblies which incorporate solar concentrators, that do not
suffer from the above-described shortcomings.
BRIEF SUMMARY OF THE INVENTION
[0005] The present invention relates to solar concentrator truss
assemblies and solar concentrator arrays. In one embodiment a solar
concentrator truss assembly has a generally V-shaped frame
including an inner surface. The inner surface has a first and
second concentrating portions. The inner surface has an unexposed
portion located between the first and second concentrating
portions. The solar concentrator truss assembly also has a solar
panel having a sun-facing surface and a bottom surface. The solar
panel is supported by the inner surface. The solar panel bridges
the inner surface to form a truss with the generally V-shaped
frame, such that the sun-facing surface and the first and second
reflective portions are exposed to each other, and the bottom
surface is exposed to the unexposed portion.
[0006] In one aspect, the first and second concentrating portions
are separated by an angle ranging from 60 to 90 degrees.
[0007] In another aspect, the first and second concentrating
portions have reflective adhesive films.
[0008] In yet another aspect, the generally V-shaped frame is
constructed from a single piece of sheet metal.
[0009] In yet another aspect, the inner surface has shoulders to
support the solar panel.
[0010] In yet another aspect, the solar panel is a stress bearing
member.
[0011] In yet another aspect, the generally V-shaped frame
additionally has at least one ventilation passage positioned below
the bottom surface of the solar panel.
[0012] In yet another aspect, the solar panel additionally has an
elongated axle extending past the generally V-shaped frame.
[0013] In yet another aspect, the generally V-shaped frame has a
dowel socket located about the unexposed portion.
[0014] In another embodiment a solar concentrator array has a
frame, including at least one elongated beam. The solar
concentrator array also has a plurality solar concentrator truss
assemblies. Each solar concentrator assembly has a generally
V-shaped frame having an inner surface. The inner surface has first
and second concentrating portions. The inner surface has an
unexposed portion located between the first and second
concentrating portions. The generally V-shaped frame has a socket.
The solar panel has a sun-facing surface and a bottom surface. The
solar panel bridges the inner surface to form a truss with the
generally V-shaped frame, such that the sun-facing surface and the
first and second reflective portions are exposed to each other. The
solar panel has an elongated axle extending past the generally
V-shaped frame. The axle is rotatably coupled to the at least one
elongated beam. The solar concentrator array also includes a motion
apparatus having a plurality of dowels. Each respective dowel is
moveably coupled to a respective socket of a respective V-shaped
frame for moving each respective solar concentrator assembly around
a respective axle.
[0015] In one aspect, the frame additionally has a second elongated
beam parallel to the at least one elongated beam. The axle of each
respective solar concentrator assembly is additionally rotatably
coupled to the second elongated beam.
[0016] In another aspect, each generally V-shaped frame is
constructed from a single piece of sheet metal.
[0017] In yet another aspect, the first and second concentrating
portions are separated by an angle ranging from 60 to 90
degrees.
[0018] In yet another aspect, the motion apparatus additionally has
an elongated connecting rod coupled to a linkage, and a motor
moveably coupled to the linkage.
[0019] In yet another aspect, the motion apparatus additionally has
a motor moveably coupled to the plurality of dowels, and a computer
assembly operationally coupled to the motor. The computer assembly
is configured to store and execute instructions for controlling the
movement of the motor.
[0020] In yet another aspect, the motion apparatus additionally has
a directional light meter operationally coupled to the computer
assembly. The directional light meter supplies a signal to the
computer assembly. The signal is used to execute instructions for
controlling the movement of the motor.
[0021] In yet another aspect, the computer assembly has stored
data. The stored data is used to execute instructions for
controlling the movement of the motor.
[0022] In yet another aspect, the stored data includes the location
of the solar collector array, time, and date.
[0023] In yet another aspect, the solar concentrator array
additionally has at least one inverter operationally coupled to the
plurality of solar concentrator assemblies.
[0024] In yet another embodiment, a solar concentrator truss
assembly includes a generally V-shaped frame formed from a single
piece of sheet metal. The generally V-shaped frame has a first
planar member and a second planar member separated by a 60 degree
angle. The first planar member has a first inner surface, the first
inner surface including a first unexposed portion and a first
concentrating portion. The first planar member also has a first
indented shoulder between the first unexposed portion and a first
concentrating portion. The second planar member has a second inner
surface. The second inner surface has a second unexposed portion
and a second concentrating portion. The second planar member also
has a second indented shoulder between the second unexposed portion
and a second concentrating portion. The first and second inner
surfaces are exposed to each other. The solar concentrator truss
assembly also has a photovoltaic panel including a sun-facing
surface, a bottom surface, a first photovoltaic end, a second
photovoltaic end, and an elongated axle extending past the
generally V-shaped frame. The first photovoltaic end is connected
with the first indented shoulder. The second photovoltaic end is
connected with the second indented shoulder. The sun-facing surface
is exposed to the first and second reflective portions. The bottom
surface is exposed to the first and second unexposed portions. The
first and second concentrating portions each have reflective
adhesive film disposed on them. The photovoltaic panel is a stress
bearing member.
[0025] For a further understanding of the nature and advantages of
the invention, reference should be made to the following
description taken in conjunction with the accompanying figures. It
is to be expressly understood, however, that each of the figures is
provided for the purpose of illustration and description only and
is not intended as a definition of the limits of the embodiments of
the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1A is a frontal perspective view of a solar
concentrator truss assembly in accordance with one embodiment of
the present invention.
[0027] FIGS. 1B and 1C are front views of the solar concentrator
truss assembly in use, in accordance with one embodiment of the
present invention.
[0028] FIG. 1D is a front view of a solar concentrator truss
assembly in accordance with one embodiment of the present
invention.
[0029] FIG. 2A is a top view of a flat metal sheet for forming a
V-shaped frame in accordance with one embodiment of the present
invention.
[0030] FIGS. 2B, 2C, and 2D are partial-top, front, and
partial-side views, respectively, of a formed V-shaped frame in
accordance with one embodiment of the present invention.
[0031] FIG. 3A is a perspective view of a solar concentrator array
in accordance with one embodiment of the present invention.
[0032] FIG. 3B is a partial cross-sectional view of the solar
concentrator array of FIG. 3A.
[0033] FIGS. 3C and 3D are partial cross-sectional views of a
portion of the solar concentrator array of FIG. 3A.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present invention relates to adjustable solar
concentrator truss assemblies. The solar concentrator truss
assembly includes a photovoltaic panel which can be preferably
orientated to face towards the sun. The solar concentrator truss
assembly utilizes a photovoltaic panel as a stressed member of the
truss to form a light weight and low cost assembly. The light
weight of the solar concentrator truss assembly enables mounting to
a simple frame or directly to a parapet of a building. The solar
concentrator truss assembly can include an axle for pivoting the
solar concentrator truss assembly about an axis. A plurality of
solar concentrator truss assemblies can be used in an array, with
each solar concentrator truss assembly being moved in unison by a
computer controlled motion mechanism. The details of the exemplary
embodiments of the present invention are explained with reference
to FIGS. 1A-3C.
[0035] Solar Concentrator Truss Assembly:
[0036] FIG. 1A shows a front perspective view of a solar
concentrator truss assembly 100. The solar concentrator truss
assembly 100 includes a generally V-shaped frame 102 and a solar
panel 104. The V-shaped frame 102 and solar panel 104 form a
structural truss configured as a triangular truss, thus, the solar
panel 104 is a structural and stress bearing member of the truss.
The truss configuration provides strength for long spans of the
solar concentrator truss assembly 100 over an axis A. For some
lengths, the solar concentrator truss assembly 100 can be strong
enough to support its own cantilevered weight, as well as withstand
compressive and buckling forces experienced from environmental
forces. For example, the solar concentrator truss assembly 100 can
be mounted only on one end to cantilever in free air. For some
lengths, the solar concentrator truss assembly 100 can be strong
enough to span long distances without buckling under its own
weight. For example, the solar concentrator truss assembly 100 can
be mounted only on both ends, thus, the truss requires no middle
support, such as shown in FIG. 3A as discussed below.
[0037] As disclosed herein, the solar panel 104 may include any
energy transforming device which transforms light energy into a
different form of energy, for example electrical energy or thermal
energy. The solar panel 104 includes a panel frame capable of
withstanding torsion, compression, and tension forces subjected
from environmental conditions. In one example, the solar panel may
be constructed as a conventional array of photovoltaic modules, and
may additionally include an internal DC to AC inverter (not shown).
The photovoltaic modules may be crystalline silicon modules,
flexible thin film modules, rigid thin film modules, multijunction
modules, or a combination thereof. The photovoltaic modules may
also incorporate plastic luminescent solar concentrators or
laminated glass luminescent solar concentrators for added
efficiency. In some embodiments, the solar panel does not require a
separate frame as the structure of the photovoltaic modules (e.g.,
laminated high strength glass) may be sufficiently rigid to act as
a stress bearing member. The solar panel is not limited to
photovoltaic technology and may be a solar thermal collector for
heating a liquid, such as water or oil.
[0038] The generally V-shaped frame 102 is preferably constructed
from a single piece of sheet metal with a central bend angle 108 of
about 60 degrees for optimum truss strength, including acceptable
tolerances, for example .+-.5 degrees. Alternatively, the generally
V-shaped frame 102 may be formed from a thermoplastic polymer sheet
or a molded thermoset polymer. The V-shaped frame 102 may also be
formed from a single piece of sheet metal using common bending
technology. Construction of the V-shaped frame is not limited to
bending technology, for example, the V-shaped frame 102 may be
formed from separate panels that welded, bonded, riveted, or bolted
together to form the generally V-shaped frame 102. The inner
surface 110 of the V-shaped frame includes concentrating portions
112 which are exposed to a sun-facing portion of the solar panel.
The concentrating portions 112 include or support adhesively
applied reflective coatings for concentrating light to the solar
panel. Commercially available high reflectivity (94%) films, such
as boPET polyester, can be used. Alternatively, the concentrating
portions 112 may include other reflective surfaces applied on top
of or integrated with the inner surface 110. Such other reflective
surfaces include mirrors, reflective metallic coatings (e.g.
chrome), or polished surfaces. The inner surface 110 of the
V-shaped frame 102 also includes an unexposed surface region 114
beneath and facing the bottom surface of the solar panel 104. For
the purposes of this disclosure, "unexposed" regards portions of
the inner surface 110 aside from the concentrating portions 112.
Thus, the unexposed surface region 114 may be exposed to direct or
indirect sunlight, however, the unexposed surface region 114 does
not concentrate light to the solar panel. The inner surface 110 of
the V-shaped frame may include at least one opening 116 passing
through the V-shaped frame to provide ventilation to the bottom of
the solar panel 104 to prevent it from overheating, as the
efficiency of a photovoltaic panel will reduce when overheated. The
openings 116 also serve to lighten the V-shaped frame 102, and
reduce the effects of wind-borne aerodynamic forces. A cooling
system (not shown), e.g., electric fans, may also be included in
the unexposed surface region 114 to help manage transient thermal
loads. A cooling system may not be required in parts of the world,
or during times of the year, where sun intensity is low. The
V-shaped frame 102 includes indented shoulders 118 for mounting the
solar panel 104. The shoulders 118 add rigidity to the V-shaped
frame 102 and also provides attachment points and a support surface
for the solar panel 104. The V-shaped frame 102 includes hems 119
to help stiffen the concentrating portions 112.
[0039] The solar concentrator truss assembly 100, which is in the
form of a braced truss includes many advantages. Less structural
parts are needed, as the solar panel 104 is a stressed member of
the truss. Accordingly, the solar panel 104 may include an axle
(not shown), or other mounting device, for mounting the solar
concentrator truss assembly 100 to a separate frame. The solar
concentrator assembly is also simple to fabricate, as the V-shaped
frame 102 may be simply scaled to accommodate off the shelf solar
panels. Some examples of off the shelf photovoltaic panels are
PV-UD185MF5 by Mitsubishi Solar and KD180GX-LP by Kyocera. Many
other photovoltaic panels are available on the market.
[0040] FIGS. 1B and 1C shows a front view of the solar concentrator
truss assembly 100 in use. The solar concentrator truss assembly
100 has been positioned to have the sun-facing surface 122, of the
solar panel 104, be normal as possible to beams of light 120. The
concentrating portions 112 are shown to preferentially reflect
beams of light 120 to the solar panel 104. Accordingly, the
concentrating portions 112 increase the amount of energy available
to the solar panel 104, resulting in greater energy output, as
compared to a solar panel 104 without the concentrating portions.
The performance of the solar concentrator truss assembly 100 may
also be expressed as a ratio R, for example the total area of
sunlight collected A.sub.C or harvested divided by the area of the
panel face A.sub.P, or R=A.sub.C/A.sub.P. A.sub.C may be the
A.sub.P plus the area of the concentrating portions 112. In one
embodiment, an preferred ratio R ranges from 1.2 to 2.0.
[0041] FIG. 1D shows an alternative front view of a solar
concentrator truss assembly 124 in use. The solar concentrator
truss assembly 124 is constructed similarly to the solar
concentrator truss assembly 100 shown in FIGS. 1A-1C. Angle 108 is
preferably 60 degrees for maximum truss strength, however, in some
cases angle 108 may be larger than 60 degrees, for example, if the
solar panel 104 is extremely wide. Thus, angle 108 may be larger
than 60 degrees to reduce weight and space requirements for a wide
solar panel 104. Accordingly, corresponding angle 126 may also be
less than 60 degrees. Alternatively, angle 108 may remain 60
degrees, however, angle 128 may be altered in increase reflectivity
of the concentrating portions 112. Angle 128 should generally be in
the range of 45-60 degrees, as angles less than 45 degrees result
in little to no light reflected 130 towards the solar panel 104,
and angles greater than 60 degrees do not optimally spread light
across the solar panel 104, accordingly, an angle of separation 132
between the concentrating portions may range from 60 to 90
degrees.
[0042] V-Shaped Frame Construction:
[0043] FIG. 2A shows a top view of a metal sheet 200 for forming a
V-shaped frame. The metal sheet 200 shows preferential fold lines
202, mounting holes 204, optional cut outs 206, and cuts 208 for a
dowel socket. The flat metal sheet 200 may be formed from a variety
of metals, for example, steel, stainless steel, and aluminum. The
mounting holes 204 and optional cut outs 206 may be formed by laser
or plasma cutting, stamping, drilling, or milling operations. The
metal sheet 200 may also be formed from a pre-perforated sheet of
metal, which includes a plurality of uniformly placed holes
throughout the sheet of metal. A pre-perforated sheet of metal can
remove the need for fabricating mounting holes 204, and optional
cut outs 206, as the perforation promotes ventilation.
[0044] FIG. 2B shows a partial top view of a V-shaped frame 210
formed from the metal sheet 200. The V-shaped frame 210 may be
formed from a conventional brake press, using manual or air
bending. As shown, shoulders 212 have been formed in the region of
the mounting holes 204 for bottom mounting of a solar panel.
Concentrating portions 214 of the V-shaped frame 210 may have
reflective coatings adhesively applied. The V-shaped frame 210 may
also include protective coatings, for example, paint, powder
coating, ceramic coating, and chrome plating. Two parallel cuts for
a dowel socket 208 are also provided.
[0045] FIG. 2C shows a front view of the V-shaped frame 210. The
V-shaped frame 210 includes hems 216 to help stiffen the
concentrating portions 214. The hems 216 may also include features
(not shown) to prevent birds from resting on the hems 216 and
potentially soiling the concentrating portions 214 or solar panel,
for example, spikes or barbs. The V-shaped frame 210 includes a
preferential bend 218 of 60 degrees, as shown. The shoulders 212
are shown to each include a bottom mounting surface 212.1 and side
mounting surface 212.2 for mounting a solar panel. The dowel socket
208 is shown formed from folding the material between the two
parallel cuts shown in FIG. 2B, into a diamond shape as shown. More
than one dowel socket 208 may be provided.
[0046] FIG. 2D shows a partial side view of the V-shaped frame 210.
The side mounting surface 212.2 of the shoulder 212 is shown with
mounting holes 204 for side mounting of a solar panel.
[0047] Solar Concentrator Array:
[0048] FIG. 3A shows a perspective view of a solar concentrator
array 300. The solar concentrator array includes a plurality of
solar concentrator truss assemblies 302, a frame 303, and a motion
apparatus 306. The plurality of solar concentrator truss assemblies
302 share the construction of the various solar concentrator truss
assemblies described herein. The frame 303 includes elongated beams
304 mounted to each side of the plurality of solar concentrator
truss assemblies 302. The beams 304 can be mounted to supports 308
for attachment to a roof or other supporting structure.
Alternatively, the beams 304 can be mounted directly to, or
integral with, a wall or parapet of a building structure, which
removes the need for supports 308. The strength of the plurality of
solar concentrator truss assemblies 302 allows for great lengths to
be spanned, and thus the solar concentrator array 300 may span an
entire rooftop, from parapet to parapet, which prevents the need to
puncture the roofs membrane with supports 308. Although two beams
304 are shown, the stiffness of plurality of solar concentrator
truss assemblies 302 requires only one beam 304, thus, the
plurality of solar concentrator truss assemblies 302 can be mounted
only on one end to cantilever in free air. The beams 304 are
preferably positioned in an east-west direction such that the
plurality of solar concentrator truss assemblies 302 can tilt to
follow the movement of the earth relative to the sun. The motion
apparatus 306 includes a computer assembly 310, a motor assembly
312, and an optional DC/AC inverter 316 with associated wiring and
electrical connections. The plurality of solar concentrator truss
assemblies 302 each generally rotate in unison around a respective
axis of rotation AR, which is generally orientated in a north-south
direction.
[0049] The computer assembly 310 includes a processor, memory, and
communications bus, all operationally connected to each other. The
communications bus can be optionally connected to an external
computer, server, or network of servers. The computer assembly 310
can be a general purpose computer or an embedded controller. The
computer assembly 310 controls the motion of the plurality of solar
concentrator truss assemblies 302 by controlling the motor assembly
312. The plurality of solar concentrator truss assemblies 302
include respective solar panels, which are preferentially
synchronized to be continuously or periodically moved to place
solar panel surfaces into positions as normal to incoming sunlight
as possible. The synchronization can be done using tables that
maximize the incoming solar irradiation for the different times of
day and year. The tables of solar irradiation angles are widely
available. An example of such tables is given in Table 9.1.4 on
page 9-13 of Marks' Standard Handbook for Mechanical Engineers by
Eugene A. Avallone, Theodore Baumeister, Ali Sadegh, and Lionel
Simeon Marks (McGraw-Hill Professional, 2006, ISBN 0071428674).
Other synchronization methods can involve solar irradiation sensors
or directional light meters operationally coupled to the computer
assembly 310, and capable of determining the angle of solar
irradiation. An example of such a solar irradiation sensor capable
of automatically determining its location through a Global
Positioning System and then calculating the angle of solar
irradiation is the Wheeler Sunpredictor.TM. by LISTECH from
Windsor, Australia. Other devices for determining the angle of
solar irradiation may also be used. Tabulated or measured values of
the angle of solar irradiation can be uploaded to the
communications bus, and stored as data on the memory. The data can
be used by additional software stored on the memory to execute
instructions by the processor to calculate the appropriate movement
of the solar concentrator truss assemblies 302. Alternatively, the
computer assembly 306 may be controlled by a external computer
communicating through the communications bus.
[0050] FIG. 3B shows a partial cross-sectional view A-A of a the
solar concentrator array 300. The view shows a drive side of a
solar concentrator truss assembly 302.1 of the plurality of solar
concentrator truss assemblies 302. Each solar concentrator truss
assembly 302.1 of the plurality of solar concentrator truss
assemblies 302 shares the same construction as shown, which can
also be mirrored to the other side of each solar concentrator truss
assembly 302. 1. The other side (not shown) of the solar
concentrator truss assembly 302.1 looks similar except it does not
generally include a dowel socket 324, dowel 326, connecting rod
328, and conduit 329, however, in some embodiments the other side
(not shown) may be identical. The solar concentrator truss assembly
302.1 includes a solar panel 318 which acts as a stressed member of
a truss. The solar panel 318 includes an axle 320 extending from
the solar panel 318, and rotatably coupled to the beam 304 by a
bearing 322. Accordingly, the solar concentrator truss assembly
302.1 may rotate about the axis of rotation AR of the axle 320. The
solar concentrator truss assembly 302.1 also includes a dowel
socket 324 which is moveably coupled to a dowel 326. The dowel 326
is further moveably connected to a connecting rod 328 which imparts
motion to the dowel 326, and further to the dowel socket 324, to
move the concentrator truss assembly 302.1 about the axle 320.
Energy collected by solar concentrator truss assembly 302.1 is
conducted through power cables into conduit 329.
[0051] FIGS. 3C and 3D shows a partial cross-sectional view B-B of
a portion of the solar concentrator array 300. FIG. 3C shows the
plurality of solar concentrator truss assemblies 302 tracking the
sun in a morning-time period, with the plurality of solar
concentrator truss assemblies 302 generally facing eastwards. FIG.
3D shows the plurality of solar concentrator truss assemblies 302
tracking the sun in a noon-time period, with the plurality of solar
concentrator truss assemblies 302 generally facing up. The
plurality of solar concentrator truss assemblies 302 is shown, each
solar concentrator truss assembly 302.1 moveably coupled to a dowel
326. In simplistic terms, the movement of the plurality of solar
concentrator truss assemblies 302 is generally described as a
six-bar linkage, the links include the frame 303, worm screw 332,
linkage 330, connecting rod 328, and at least two solar
concentrator truss assemblies 302.1, with the frame 303 being a
fixed link. As the worm screw 332 moves in and out, the plurality
of solar concentrator truss assemblies 302 tilt about respective
axles 320. FIG. 3C shows the worm screw 332 extended towards the
west which causes the linkage 330 to extend the connecting rod 328
and cause the plurality of solar concentrator truss assemblies 302
to face eastwards. FIG. 3D shows the worm screw 332 generally
centrally positioned which causes the linkage 330 to lower the
connecting rod 328 and cause the plurality of solar concentrator
truss assemblies 302 to face upwards. The worm screw 332 may also
be extended towards the east which causes the linkage 330 to again
raise the connecting rod 328 and cause the plurality of solar
concentrator truss assemblies 302 to face westwards (not
shown).
[0052] Each solar concentrator assembly 302.1 rotates about a
respective axle 320 due receiving force from a respective dowel
326. The dowels 326 are moveably connected to the connecting rod
328, each dowel 326 being in a fixed relationship to each other.
The connecting rod 328 is further moveably coupled to the linkage
330. The linkage 330 translates linear motion imparted by motor
assembly 312 into circular motion about each axle 320. In use, the
motor assembly 312 moves the worm screw 332 in a linear direction,
for example, back and forth along the east-west direction as shown.
The motor assembly 312 and axles 320 are fixed in location relative
to the frame 303, however, the worm screw 332, linkage 330, and
connecting rod 328 (and dowels 326) are moveable relative to the
frame 303. Thus, linear movement of the worm screw 332 causes the
linkage 330 and connecting rod 328 (and dowels 326) to move, and in
turn cause the plurality of solar concentrator truss assemblies 302
to rotate in unison about each respective axle 320. The pattern of
movement is determined by the relationship between the dowels 326
and axles 320. As the axles 320 are fixed relative to the frame
303, each dowel 326 moves in a circular pattern about each
respective axle 320. The dowels 326 are fixed in location with
respect to each other, thus, the circular movement of each dowel
326 causes the connecting rod 328 to maintain a horizontal attitude
and "rock" back and forth. The motion of the plurality of solar
concentrator truss assemblies 302 is generally limited to follow
the movement of the earth relative to the sun, however, the
plurality of solar concentrator truss assemblies 302 can be
completely inverted to cause the solar panels to face down in
inclement weather. The motor assembly 312 can be a worm driven gear
box assembly having a high gear ratio. Many worm driven gear box
assemblies that produce linear motion are available on the market.
One example is Action Jac.TM. linear actuator by Nook Industries,
Inc., Ohio. Other mechanisms for the motion apparatus 306 are
possible. One example is an engagement of the gears on a driveshaft
connected to respective gears on each solar concentrator truss
assembly 302.1. Another example is using a cam guide on the
connecting rod 328 for each dowel, for example a groove machined in
the cam guide or a mounted track. Thus, each dowel would follow a
circular cam profile which further eliminates the need for the
linkage 330. Other examples of the mechanisms for adjusting the
panel pivot angle are rack and pinion, belt and pulley, and
hydraulic or pneumatic cylinder drives, or a combination of
different mechanisms.
[0053] As will be understood by those skilled in the art, the
present invention may be embodied in other specific forms without
departing from the essential characteristics thereof. For example,
the motion apparatus 306 may receive electrical energy directly
from the photovoltaic panels. Furthermore, the frame 304 may host
different numbers of photovoltaic panels having differing sizes.
The frame 304 may also impart a second axis of motion, (e.g., tilt
the about the east-west axis shown in FIG. 3A) as described in
co-assigned U.S. patent application Ser. No. 12/353,143, the
entirety of which is incorporated by reference herein. Many other
embodiments are possible without deviating from the spirit and
scope of the invention. These other embodiments are intended to be
included within the scope of the present invention, which is set
forth in the following claims.
* * * * *