U.S. patent application number 12/367977 was filed with the patent office on 2011-08-18 for rack assembly for solar energy collecting module.
Invention is credited to Linus Eric Wallgren.
Application Number | 20110198304 12/367977 |
Document ID | / |
Family ID | 43622789 |
Filed Date | 2011-08-18 |
United States Patent
Application |
20110198304 |
Kind Code |
A1 |
Wallgren; Linus Eric |
August 18, 2011 |
Rack Assembly for Solar Energy Collecting Module
Abstract
A rack assembly for supporting a solar energy collecting module
on a support surface is provided that has a plurality of upright
frames and a transverse element connected to the plurality of
upright frames. An associated method of constructing the rack
assembly is also provided.
Inventors: |
Wallgren; Linus Eric;
(Bethesda, MD) |
Family ID: |
43622789 |
Appl. No.: |
12/367977 |
Filed: |
February 9, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61049567 |
May 1, 2008 |
|
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Current U.S.
Class: |
211/41.1 |
Current CPC
Class: |
F24S 40/85 20180501;
F24S 25/13 20180501; Y10T 29/49826 20150115; Y02E 10/50 20130101;
F24S 25/16 20180501; H02S 20/24 20141201; Y02E 10/47 20130101 |
Class at
Publication: |
211/41.1 |
International
Class: |
A47F 7/00 20060101
A47F007/00 |
Claims
1-23. (canceled)
24. A solar energy collection assembly for mounting on a support
surface, the assembly comprising: a solar collecting module, a wind
deflector, a rack assembly including: a plurality of upright
triangular-shaped frames, each frame comprising: a first leg
extending substantially parallel to the support surface in a first
direction, a second leg extending from the first leg at a first
angle relative to the first leg, the second leg supporting the
module at an angle relative to the support surface, a third leg
extending from the first leg at a second angle relative to the
first leg and connected to the second leg to form the
triangular-shaped frame, and a transverse member connected to the
first leg of each of the plurality of frames and extending
substantially parallel to the support surface in a second
direction, the third leg supporting the wind deflector at the
second angle relative to the first leg, the wind deflector being
separate from the third leg and extending along substantially the
entire length of the third leg.
25. The assembly of claim 24 further comprising at least three
triangular shaped frames and at least two solar collecting
modules.
26. The assembly of claim 24 further comprising at least three
solar collecting modules, and wherein the plurality of
triangular-shaped frames numbers one more than the number of solar
collecting modules.
27. The assembly of claim 24 wherein at least one leg is made of
roll-formed sheet metal.
28. The assembly of claim 24 wherein each of the legs is made of
roll-formed sheet metal.
29. The assembly of claim 24 wherein the transverse member is made
of roll-formed sheet metal.
30. The assembly of claim 29 wherein the roll-formed sheet metal of
the transverse member is corrosion resistant steel.
31. The assembly of claim 29 wherein the roll-formed sheet metal of
the transverse member defines a ballast tray.
32. The assembly of claim 31 wherein the transverse member has an
open channel for receiving a ballast.
33. The assembly of claim 24 wherein the solar collecting module
includes an edge, and wherein the wind deflector includes a flange
adapted to retain the edge of the solar collecting module.
34. The assembly of claim 24 wherein the solar collecting module
includes an edge and wherein the second leg comprises a clip
securing the edge of the solar collecting module.
35-42. (canceled)
43. A solar energy collection assembly for mounting on a support
surface, the assembly comprising: a solar collecting module, a wind
deflector, a rack assembly including: a plurality of upright
triangular-shaped frames, each frame comprising: a first leg
extending substantially parallel to the support surface in a first
direction, a second leg extending from the first leg at a first
angle relative to the first leg, the second leg supporting the
module at an angle relative to the support surface, a third leg
extending from the first leg at a second angle relative to the
first leg and connected to the second leg to form the
triangular-shaped frame, and a transverse member connected to the
first leg of each of the plurality of frames and extending
substantially parallel to the support surface in a second
direction, the third leg supporting the wind deflector at the
second angle relative to the first leg, the wind deflector being
separate from the third, the wind deflector spanning the distance
between two adjacent frames of the plurality of frames.
44. The assembly of claim 43 wherein the rack assembly comprises
three triangular-shaped frames.
45. The assembly of claim 44 wherein the wind deflector is a first
wind deflector and further comprising a second wind deflector.
46. The assembly of claim 45 wherein the first wind deflector and
the second wind deflector extend along substantially the entire
width of the rack assembly.
47. The assembly of claim 43 further comprising at least three
solar collecting modules, and wherein the plurality of
triangular-shaped frames numbers one more than the number of solar
collecting modules.
48. The assembly of claim 43 wherein at least one leg is made of
roll-formed sheet metal.
49. The assembly of claim 43 wherein the transverse member is
roll-formed sheet metal.
50. The assembly of claim 43 wherein the transverse member defines
a ballast tray for receiving a ballast.
51. The assembly of claim 43 wherein the solar collecting module
includes an edge and wherein the second leg comprises a clip
securing the edge of the solar collecting module.
Description
RELATED APPLICATION DATA
[0001] This application claims priority under 35 U.S.C.
.sctn.119(c) to U.S. Provisional Patent Application Ser. No.
61/049,567, filed on May 1, 2008, which is hereby incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention relate to a rack
assembly for mounting solar energy collecting modules and an
associated method for constructing a rack assembly.
DESCRIPTION OF RELATED ART
[0003] Pholovoltaies (PV) is the field of technology and research
related to the application of solar cells for energy by converting
sunlight directly into electricity. Due to the growing demand for
clean sources of energy, the manufacture of solar cells and PV
arrays has expanded dramatically in recent years. These mechanisms
may be may be ground-mounted or built into the roof or walls of a
building, financial incentives, such as preferential feed-in
tariffs for solar-generated electricity, and net metering, have
supported solar PV installations in many countries.
[0004] A variety of solar energy collecting modules currently
exist. One such module is a PV panel which converts solar energy
into electricity. Another module is a solar thermal collector which
harnesses solar energy for heal. The modules can have different
geometries, but are commonly made with a generally flat
construction. PV panels are often electrically connected in
multiples as solar photovoltaic arrays to convert energy from the
sun into electricity. In operation, photons from sunlight knock
electrons into a higher state of energy, creating electricity.
Solar cells produce direct current electricity from light, which
can be used for such tasks as powering equipment or recharging a
battery. Cells require protection from the environment and are
packaged usually behind a glass sheet. When more power is required
than a single cell can deliver, cells are electrically connected
together to form PV modules, or solar panels.
[0005] Multiple issues have prevented the growth of solar energy
from becoming even more explosive. The most pervasive of these
issues may be installation and material costs. However, due to
economies of scale, solar panels become less expensive as people
use and buy more and as manufacturers increase production to meet
demand. Thus, the cost and price is expected to drop in the years
to come.
[0006] Solar energy collecting modules are currently used in a
variety of settings, including commercial, residential, and
industrial environments. These modules are typically mounted on a
structure secured to a support surface, such as a rooftop.
Different considerations affect the design and construction of the
mounting structures for the modules. These factors include ease of
manufacture and installation, minimization of related costs, and
resistance to environmental factors such as wind forces.
[0007] Various problems have hindered the use and development of
existing mounting structures. For example, because of lift forces
created by wind gusts, existing mounting structures have often
generated inadequate frictional forces to maintain satisfactory
contact with the underlying support surface. Despite efforts made
to reduce mounting structure surface area to create a mounting
structure that minimizes lilt forces created by the wind, it has
often been viewed as necessary to secure the mounting structures to
the rooftop or other base supporting surface. This attachment
process often proves to be harmful and destructive to the
underlying supporting surface. For example, the installer may be
required to penetrate the roof shingles, roofing paper, and
sheathing. This penetration makes the roofless weather resistant
and thus may result in damage to the building itself.
[0008] Additionally, materials for the mounting structures are
often expensive and manufacturing and installation have been
complicated, thus adding to the expense of the mounting structure.
An increase to the cost of the system negatively impacts the
financial advantage that consumers expect from a solar energy
solution.
[0009] Generally, solving any one of the aforementioned problems
has magnified the other existing problems and no suitable solution
has been found for a secure mounting structure having a reasonable
cost.
[0010] Accordingly, a practical solution is needed that provides a
secure mounting rack assembly with a novel construction for
mounting solar energy collecting modules. Additionally, a solution
is needed for providing an efficient and inexpensive method of
constructing the novel rack assemblies.
SUMMARY OF THE EMBODIMENTS
[0011] In a first aspect, an embodiment comprises a rack assembly
for supporting a solar energy collecting module on a support
surface. The rack assembly comprises a plurality of upright frames
and a transverse element connected to the plurality of frames. Each
frame comprises a first base leg extending substantially parallel
to the support surface in a first direction and a second leg
extending from the first leg at an angle relative to the first leg.
The second leg supports the solar energy collecting module at an
angle relative to the support surface. A transverse member is
connected to the first leg of each of the plurality of frames and
extends substantially parallel to the support surface in a second
direction substantially perpendicular to the first direction. The
plurality of upright frames is constructed by roll forming at least
one leg of the upright frame from sheet metal.
[0012] In a further aspect, an embodiment comprises a rack assembly
for supporting a solar energy collecting module on a support
surface. The rack assembly comprises a plurality of upright
triangular frames. Each triangular frame comprises a first leg
extending substantially parallel to the support surface in a first
direction and a second leg extending from the first leg at a first
angle relative to the first leg. The second leg supports the solar
energy collecting module at an angle relative to the support
surface. Each frame additionally includes a third leg extending
from the first leg at a second angle relative to the first leg, the
third leg supporting a wind deflector plate at an angle relative to
the support surface, the third leg connected with the second leg to
form the triangular frame. Each frame further includes a transverse
member connected to the first leg of each of the plurality of
frames and extending substantially parallel to the support surface
in a second direction.
[0013] In another aspect, an embodiment comprises a method for
constructing a rack assembly for supporting a solar energy
collecting module on a support surface. The method comprises roll
forming a first and second section of channel from sheet metal. The
first and second sections of channel are connected to form an
upright frame. A transverse element is attached to the upright
frame. The upright frame comprises a first leg formed from the
first section of channel and extending substantially parallel to
the support surface. The upright frame also comprises a second leg
formed from the second section of channel and extending from the
first leg at an angle relative to the first leg.
[0014] In an additional aspect, an embodiment comprises a method
for on-site construction of a rack assembly for supporting a solar
energy collecting module on a support surface. The method comprises
providing for a roll forming machine and a coil of sheet metal
adjacent an installation location, using the roll forming machine
to form a plurality of channels from the coil of sheet metal, and
constructing an upright frame from the channels. The frame
comprises a horizontally extending leg, a first upwardly angled
leg, and a second upwardly angled leg. A transverse element is
connected to a plurality of upright frames.
[0015] Other objects, features, and characteristics of the present
embodiments will become apparent upon consideration of the
following description and the appended claims.
BRIEF DESCRIPTION OF THE FIGURES
[0016] In the drawings, like reference characters generally refer
to the same pans throughout the different views. In the following
description, various embodiments of the present invention are
described with reference to the following drawings, in which:
[0017] FIG. 1 is a front perspective view of a rack assembly
according to a first embodiment.
[0018] FIG. 2 is a rear perspective view of a rack assembly
according to the first embodiment.
[0019] FIG. 3 is a side view of a rack assembly in accordance with
an additional embodiment of the invention.
[0020] FIG. 4 is a perspective view of a clip for use with multiple
embodiments of the invention.
[0021] FIG. 5 is a perspective view of a rack assembly according to
a further embodiment of the invention.
[0022] FIG. 6 is a top plan schematic view of a rack assembly array
in accordance with an additional embodiment of the invention.
[0023] FIG. 7 is a perspective view illustrating an alternative
rack assembly embodiment.
[0024] FIG. 8 is a perspective view illustrating a pop-rivet
attachment of a stiffening rib to a frame in accordance with the
alternative embodiment of the invention.
[0025] FIG. 9 is a perspective view illustrating laminates attached
to the stiffening ribs in accordance with the alternative
embodiment of the invention.
[0026] FIG. 10 is a perspective view illustrating a junction
between the laminate, the stiffening rib, and the rack assembly in
accordance with the alternative embodiment of the invention.
DETAILED DESCRIPTION
[0027] FIG. 1 illustrates a first embodiment of a rack assembly
100. The rack assembly 100 may include a plurality of frames 104.
Each frame 104 may include a base leg 112 and one or more
additional legs 114 and 116. The rack assembly may additionally
include clips 106 and panels 122 having flanges 108. A transverse
member 110 may extend the length of the rack assembly 100 and
friction pads 130 may be affixed to the base of the rack assembly
100.
[0028] In the illustrated embodiment, two solar energy collecting
modules 102 are mounted on three frames 104. The solar energy
collecting modules 102 are of the kind that is generally flat, such
as photovoltaic modules. The solar energy collecting modules 102
are mounted on the rack assembly 100 at a predetermined angle and
are secured by clips 106 and flange portions 108 of panels 122. The
transverse member 110 extends the length of the rack assembly 100
and is secured to the frames 104 on the base leg 112 of each of the
frames 104. The transverse member 110 may serve as a ballast tray
for adding additional weight to the rack assembly 100.
[0029] The rack assembly 100 may be mounted on relatively leveled
and mildly sloping surfaces, such as for example on the roof of a
building. The friction pads 130 affixed to the bottom of the frames
104 may provide additional support for retaining the rack assembly
100 on a support surface. The friction pads 130 may be made of
rubber and may be affixed in a variety of configurations using one
of a variety of techniques. In the illustrated embodiment, one
friction pad 130 is juxtaposed adjacent each end of the base leg
112 of the frame 104. However, it should be understand that one
friction pad 130 or a larger number of friction pads 130 may be
affixed in alternative configurations.
[0030] FIG. 2 illustrates the rack assembly 100 as shown in FIG. 1
from a rear perspective view. As can be seen more clearly, two
panels 122 extend the width of the rack assembly 100. The panels
122 are dimensioned to serve as wind deflectors to eliminate uplift
forces. Each panel 122 spans the distance between two frames 104,
which corresponds approximately to the width of each solar energy
collecting module 102.
[0031] Longer panels that span the lull width of the rack assembly
100 may also be used. The panels 122 may be secured to the frames
104 using any appropriate fastening method, such as adhesive,
screws, bolts, or pop rivets. As set forth above, with respect to
FIG. 1, the panels 122 include flange portion 108 which serves to
retain the lop edges of each solar energy collecting module
102.
[0032] FIG. 3 is a side view of a rack assembly 300. The frame 304
shown in this embodiment has a triangular shape. The frame 304
includes a base leg 312 and two angled legs 314, 316. Each leg 312,
314, 316 is preferably comprised of U-shaped channel pieces. The
U-shaped channel pieces may be easily manufactured from roll-formed
sheet metal, as will be described in more detail below. The legs
312, 314, and 316 may be juxtaposed at pre-selected angles 324,
326, and 328.
[0033] Other frame geometries may also be used, frames may have
less than three legs or more than three legs. Frames may have
closed geometries, such as a triangle or square, or open
geometries, such as an open angle formed by two legs.
[0034] Using a triangle frame embodiment as illustrated in FIG. 3,
the base leg 312 rests on a support surface. One or more frictional
pads 330 may be affixed to a portion of the base leg 312 that
contacts the support surface. In the embodiment of FIG. 3, the
first angled leg 314 supports the solar energy collecting module
302, and the second angled leg 316 supports a panel 322.
[0035] The incline angle 324 of first angled leg 314 may be
predetermined in order to maximize the interception of solar
energy. Similarly, the incline angle 328 between the first 314 and
second 316 angled legs may be predetermined to utilize the wind
deflecting properties of the panels 322 and to control the amount
of uplift generated by wind passing over the rack assembly 300. The
incline angles 324, 326, and 328 of the first angled leg 314 and
the second angled leg 316 may be adjusted by varying the lengths of
the first and second angled legs 314, 316. Additionally, one or
more transverse members 310 may be connected to the base leg 312 of
the frame 304. The transverse member 310 may be used as a ballast
tray.
[0036] FIG. 4 illustrates a clip 406 used to secure the bottom edge
of solar energy collecting modules 402. The height of the clip 406
may be selected to approximately equal the height of the solar
energy collecting module 402 such that the solar energy collecting
module 402 can be firmly and securely inserted into the clip 406.
The clip 406 may be manufactured separately from the frame 404 of
the rack assembly 400 and secured onto the frame 404 using
fasteners such as screws, bolts, or pop rivets. The clip 406 may
alternatively be made by punching out and bending a piece of the
frame 404. A lab 452 maybe used to separate and longitudinally
align adjacent solar energy collecting modules 402.
[0037] FIG. 5 illustrates an additional embodiment of a rack
assembly 500 in which seventeen frames 504 support sixteen solar
energy collecting modules 502. The embodiments shown in FIGS. 1-5
are exemplary only and rack assemblies with different numbers of
frames may be constructed to hold different numbers of solar energy
collecting modules depending on need. Longer rack assemblies may
require multiple pieces of transverse member 510 in order to
connect all the frames.
[0038] FIG. 6 is a lop plan schematic view of a rack assembly array
600. As shown in FIG. 6, rack assemblies 610 are combined to form a
rack assembly array 600. Although shown with three rack assemblies
610, a rack assembly array may include more or fewer rack
assemblies. Additionally, the rack assemblies do not need to be of
the same size. Rows of rack assemblies 610 may be connected to
adjacent rows with sections of galvanized steel strut 602. The
steel strut 602 ties the sections of rack assemblies 610 together
to spread force loads and may additionally be used as mounting
points to which electrical conduit runs can be affixed.
[0039] FIG. 7 is a perspective view illustrating an alternative
rack assembly embodiment. A rack assembly 700 includes a frame 704
for use with a solar energy collecting module in the form of an
unframed PV laminate. The frame 704 may have a triangular
configuration including a base member 712 connected with angled
members 714 and 716. One or more stiffening ribs 740 may be
provided and may be connected to angled members 714 of multiple
frames 704, the connection may be facilitated through the use of
pop-rivets or other fasteners. The rack assembly 700 may also
include one or more transverse members (1110, FIG. 11), which may
serve as ballast trays.
[0040] In order to mount PV laminates, an adhesive or other
fastening means may be applied to affix the PV laminates to the
stiffening ribs 740. In addition to supporting the PV laminates,
the stiffening ribs 740 may function as a bonded grounding path for
the assembly 700.
[0041] Similarly to the embodiments described above with respect to
FIGS. 1-5, the rack assembly 700 may be constructed from galvanized
sheet metal members assembled with pop-rivets or other
fasteners.
[0042] FIG. 8 is a perspective view illustrating a pop-rivet
attachment 842 of a stiffening rib 840 to a frame 804 in accordance
with the alternative embodiment of FIG. 7. More specifically, the
stiffening rib 840 is attached by the pop-rivet attachment 842 to
angled arm 814 of the frame 804. In the illustrated embodiment, a
flange 808 may provide additional stability.
[0043] FIG. 9 is a perspective view illustrating PV laminates 950
attached to a plurality of stiffening ribs 940 in accordance with
an embodiment of the invention. Such attachment is preferably
accomplished through the use of an adhesive, but may alternatively
be accomplished through other fastening mechanisms. Flange portions
908 of panels 922 may operate to encase edges of the PV laminates
950. In the illustrated embodiment, two PV laminates 950 are
mounted on three stiffening ribs 940. However, it should be
understood that in alternative embodiments, any suitable number of
stiffening ribs 940 may be implemented for attachment to the PV
laminates 950.
[0044] FIG. 10 is a perspective view illustrating a junction
between PV laminates 1050, a stiffening rib 1040, and a rack
assembly 1004 in accordance with the embodiment of the invention
illustrated in FIGS. 7-9. FIG. 10 additionally illustrates a
pop-rivet connector 1042 securing the stiffening rib 1040 to the
rack assembly 1004. Additionally, panels 1022 may include flanges
1008 that cover an edge of the stiffening rib 1040 and further
encase an edge of the PV laminates 1050.
[0045] FIG. 11 is a side view illustrating an additional embodiment
of the invention. In this embodiment, one or more transverse ribs
1140 are attached to angled arm 1114 by pop-rivet attachment 1142.
One or more stiffening ribs 1144 are separately attached to a PV
laminate 1150, preferably using adhesive 1146. The shapes of the
transverse ribs 1140 and stiffening ribs 1144 are complementary,
such that the PV laminate 1150 may be attached to the rack assembly
1100 by inserting the stiffening ribs 1144 into the transverse ribs
1140. The two complementary ribs may be secured together using
locking labs, adhesive, fasteners, such as pop-rivets or screws, or
other appropriate means. In this manner, the rack assembly 1100 may
be assembled at the job site, and the stiffening ribs 1144 may be
adhered to the PV laminate 1150 at another location in a controlled
environment in order to minimize temperature or moisture concerns.
The assembly of PV laminate 1150 and stiffening ribs 1144 may then
be transported to the job site and snapped onto the transverse ribs
1140 previously mounted to the rack assembly 1100.
[0046] The rack assembly according to the described embodiments has
a relatively simple construction, which may be easily manufactured.
Referring to FIG. 1, the frames 104 of rack assembly 100 may be
constructed using channel pieces fabricated from a roll forming
process. Roll forming is a continuous bending operation in which a
long strip of is passed through consecutive sets of rolls, or
stands, each performing only an incremental part of a bend, until a
desired cross-sectional profile is obtained. A variety of
cross-sectional profiles can be produced using varied roll tools.
Roll formed sections are generally lighter and stronger than
extrusions of a similar shapes, as they have been work hardened in
a cold state. Other advantages of roll forming include the fact
that that roll formed parts can be made having a finish or already
painted, furthermore, in comparison to extrusion processes, labor
for roll forming is greatly reduced.
[0047] Roll forming lines can be set up with multiple
configurations to punch and cut off parts in a continuous
operation, for cutting a part to length, the lines can be set up to
use a pre-cut die where a single blank runs through the roll mill,
or a post-cut die where the profile is cutoff after the roll
forming process, features may be added in a hole, notch,
embossment, or shear form by punching in a roll forming line. These
part features can be done in a pre-punch application before roll
forming starts, in a mid-line punching application during roll
forming, or a post punching application after roll forming is
completed. Some roll forming lines incorporate only one of the
above punch or cutoff applications, others incorporate some or all
of the applications in one line.
[0048] A roll forming process for forming the channel pieces used
in the frames of disclosed embodiments may include feeding sheet
metal from a coil through a plurality of roll pass combinations in
a roll pass machine. The sheet metal may be galvanized steel.
Galvalume or any other appropriate sheet metal. In accordance with
the embodiments displayed in FIGS. 1-10, the resulting channel
pieces may have a substantially U-shape with a flat bottom wall and
a pair of opposed upstanding side walls. The roll pass machine may
include flying punches to form cut-outs and sheering devices to cut
the channel into pieces of predetermine lengths. Once formed, the
channel pieces are connected together using fasteners to form
frames. Three channel pieces of different lengths may be fastened
together into a triangular shape having a base leg and two angled
legs.
[0049] Another manufacturing embodiment includes forming each of
the frames from a single channel piece. Instead of roll forming
each leg as a separate piece of channel, the roll pass machine may
be used to form a single channel long enough to form a full frame.
Notches may be formed in the sidewalls of the channel to facilitate
bending the single channel piece into the frame shape. The roll
pass machine may use one or more flying punches to cut the notches
during the roll forming process, or, as set forth above, the
notches may be cut independently before or after the channel is
formed. The notched piece of channel can then be folded into a
frame and fastened together using fasteners.
[0050] Following the formation of frames, a transverse member (such
as member 110 shown in FIG. 1) is fastened to a predetermined
number of frames to form a rack assembly. A single transverse
member may be used to span the full width of the rack assembly or
multiple transverse members may be used to span the full width. The
transverse element may also be formed using a roll forming
process.
[0051] Referring to FIG. 4, clip 406 may be formal from cut or
stamped sheet metal patterns. A first bend is used to form the lop
of the clip and a second bend is used to form the bottom of the
clip that is fastened to the frame. A clip may also be made during
the roll forming process of the channels. A flying punch may form a
cutout portion in a channel which may then be bent to form the
clip.
[0052] Referring to FIGS. 1 and 2, panel 122 may be formed from cut
or stamped sheet metal patterns. A first bend may be used to form
the flange portion 108. The panel may be secured to the rack
assembly 104 after the solar energy collecting module 102 is placed
on the assembly and into the clips 106 so that the flange portion
108 retains the top edge of the solar energy collecting module
102.
[0053] Furthermore, with respect to the embodiment of FIGS. 7-11.
PV laminates 750 are attached to the stiffening ribs 740 by means
of an adhesive. Adhesion of the sheet metal stiffening ribs 740 to
the backside of the laminate 740 is preferably accomplished in a
controlled environment in order to minimize temperature or moisture
concerns. Attachment of the stiffening ribs 740 to the triangular
base structures 704 is preferably accomplished by implementing a
pneumatic pop-rivet gun. This can be accomplished al the job
site.
[0054] The case of manufacture allows for construction of a rack
assembly on-site at an installation location. A portable roll
forming machine may be brought to an installation location where
the channels for the frame and transverse members may be
fabricated. The channels may then be fastened together to form the
frames and the transverse member fastened to the frames to form a
rack array, for a rooftop installation, the channels and transverse
member may be formed on the ground and then lifted up to the roof
where the frames and rack array are formed. A conveyor bell may be
used to lift the rack array elements to the roof.
[0055] Having described certain embodiments of the invention, it
will be apparent to those of ordinary skill in the art that other
embodiments incorporating the concepts disclosed herein may be used
without departing from the spirit and scope of the invention. The
described embodiments are to be considered in all respects as only
illustrative and not restrictive.
* * * * *