U.S. patent application number 12/886973 was filed with the patent office on 2011-03-24 for isolation mount and photovoltaic module and roofing system incorporating the same.
Invention is credited to Annett Eiffert, Patrina Eiffert.
Application Number | 20110067327 12/886973 |
Document ID | / |
Family ID | 43767663 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110067327 |
Kind Code |
A1 |
Eiffert; Patrina ; et
al. |
March 24, 2011 |
ISOLATION MOUNT AND PHOTOVOLTAIC MODULE AND ROOFING SYSTEM
INCORPORATING THE SAME
Abstract
An isolation mount for supporting, for example, a photovoltaic
cell. The isolation mount includes an isolator body, a first
membrane adjacent to a lower surface of the body, and a second
membrane extending over the isolator body that includes a
peripheral margin that is at least partially sealed or adhered to
the first membrane. At least one connector is supported by the
isolator body and at least one fastener extends through the second
membrane to secure the connector to the isolator body. The
connector may include a mounting rail, posts, or an air channel
assembly. The isolation mount construction may be incorporated into
a photovoltaic module or photovoltaic roofing system for use on the
roof of a building.
Inventors: |
Eiffert; Patrina; (Golden,
CO) ; Eiffert; Annett; (Fair Oaks, CA) |
Family ID: |
43767663 |
Appl. No.: |
12/886973 |
Filed: |
September 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11933902 |
Nov 1, 2007 |
7810286 |
|
|
12886973 |
|
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Current U.S.
Class: |
52/173.3 ;
52/698; 52/745.21 |
Current CPC
Class: |
Y02E 10/50 20130101;
F24S 25/11 20180501; Y02B 10/10 20130101; Y02E 10/47 20130101; F24S
2025/6001 20180501; F24S 25/61 20180501; Y02B 10/20 20130101; H02S
20/23 20141201; F24S 25/60 20180501 |
Class at
Publication: |
52/173.3 ;
52/698; 52/745.21 |
International
Class: |
E04D 13/18 20060101
E04D013/18; E04B 1/38 20060101 E04B001/38; E04B 7/18 20060101
E04B007/18 |
Claims
1. An isolation mount, comprising: an isolator body having upper
and lower surfaces; a first membrane adjacent to said lower
surface; a second membrane extending over said isolator body and
including a peripheral margin that is sealed to said first
membrane; at least one connector supported by said isolator body;
and at least one fastener extending through said second membrane
and securing said at least one connector to said isolator body.
2. An isolation mount according to claim 1 wherein said isolator
body is a thermal barrier.
3. An isolation mount according to claim 1 including a relief
fitting extending through said second membrane.
4. An isolation mount according to claim 1 wherein said at least
one fastener extends from said isolator body.
5. An isolation mount according to claim 4 wherein said at least
one connector includes a mounting rail.
6. An isolation mount according to claim 4 wherein said at least
one connector includes an air channel assembly.
7. An isolation mount according to claim 4 wherein said at least
one connector includes a mounting post.
8. An isolation mount according to claim 7 wherein said at least
one post extends through said second membrane.
9. An isolation mount according to claim 8 including a connector
seal extending around each said at least one post, said connector
seal including a flange portion sealed to said second membrane.
10. An isolation mount according to claim 1 including a washer
element interposed between said isolator body and said second
membrane, wherein said at least one fastener extends from said
washer element.
11. An isolation mount according to claim 10 including a third
membrane interposed between said isolator body and said washer
element.
12. An isolation mount according to claim 1 wherein the seal is at
least one of a hermetic seal or a waterproof seal.
13. A photovoltaic module for use on the roof of a building,
comprising: at least one isolator body having upper and lower
surfaces; a first membrane adjacent to said lower surface; a second
membrane extending over said isolator body and including a
peripheral margin that is sealed to said first membrane; and at
least one photovoltaic cell secured to said isolator body.
14. A photovoltaic module according to claim 13 including an air
channel assembly interposed between said isolator body and said
photovoltaic cell.
15. A photovoltaic module according to claim 13 wherein said
photovoltaic cell is secured to said second membrane with
adhesive.
16. A photovoltaic module according to claim 13 wherein said
photovoltaic cell is secured to said second membrane with
cooperative hook and loop material.
17. A photovoltaic module according to claim 13 including a
plurality of connectors supported by said isolator body and wherein
said photovoltaic cell is secured by said connectors.
18. A photovoltaic module according to claim 17 including at least
one fastener extending from said second membrane and securing each
said connector to said isolator body.
19. A photovoltaic module according to claim 18 wherein said at
least one fastener is captive to said membrane by a washer that is
induction welded to said membrane.
20. A photovoltaic module according to claim 18 including a roof
deck panel supporting said module.
21. A photovoltaic module according to claim 17 wherein said
photovoltaic cell is a non-glass solar panel and said connectors
secure said solar panel along at least a portion of one of its
edges.
22. A photovoltaic module according to claim 21 wherein said
connectors each comprise a clip.
23. A photovoltaic module according to claim 21 wherein said
connectors each comprise a strap.
24. A photovoltaic roofing system for use on the roof of a
building, the system comprising: at least one isolator body; a
first membrane disposed between said at least one isolator body and
the building; at least one second membrane extending over said at
least one isolator body; means to seal the first membrane to the at
least one second membrane; a plurality of connectors supported by
said at least one isolator body; and at least one photovoltaic cell
mounted to said connectors.
25. A photovoltaic roofing system according to claim 24 including
at least one fastener extending through said second membrane and
securing each said connector to said isolator body.
26. A photovoltaic roofing system according to claim 25 wherein
each connector includes a mounting rail.
27. A photovoltaic roofing system according to claim 25 wherein
each connector includes a mounting post.
28. A photovoltaic roofing system according to claim 24 including a
roof deck disposed between said first membrane and said
building.
29. A method for deploying a photovoltaic system on a surface, the
method comprising: pre-assembling a first membrane and a second
membrane to form a cavity, said second membrane including a
plurality of connectors; securing said first membrane to the
surface; filling said cavity with foam; and mounting at least one
photovoltaic cell to said connectors.
30. The method according to claim 29 including induction welding a
captive fastener to said second membrane.
31. The method according to claim 29 wherein said foam is injected
into said cavity.
32. The method according to claim 29 wherein said surface is the
ground and wherein said first membrane is comprised of geomembrane
material.
33. The method according to claim 32 wherein said first membrane is
secured to the ground with a plurality of stakes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/933,902, filed Nov. 1, 2007, the disclosure
of which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The traditional roof assembly provides protection to the
building and its contents from the effects of weather. The
technology of the present application relates to a roofing assembly
that incorporates solar panels as well as provides protection to
the building and its contents from the effects of weather.
BACKGROUND
[0003] Commercial flat and low-sloped roofing systems provide
moisture resistance, thermal resistance (R-value) and dimensional
stability as part of the building envelope.
[0004] Flat and low-slope roof membranes fall into two main
materials categories a) polymer based and b) bitumen based. Within
polymer based low-slope roof systems there are two major types:
Thermosets (TS), including Ethylene Propylene Diene Monomer (EPDM)
and Chlorosulfonated Polyethylene (CSPE), and Thermoplastics (TP),
including Poly Vinyl Chloride (PVC), Thermoplastic Polyolefin
(TPO), Chlorinated Polyethylene (CPE) and Keytone Ethylene Ester
(KEE). Within the bitumen based low-slope roof systems there are
two categories: Built-up Roofing (BUR) including Asphalt and Coal
Tar and Modified Bitumen (Mod. Bit.) including Atactic
polypropylene (APP) and Styrene-Butadiene Styrene (SBS).
[0005] Membrane roof materials and systems are designed to meet the
requirements of the building in specific climatic conditions and
are specified based on the cost, long-term weatherability,
resistance to stress caused by expansion and contraction from
fluctuations in temperature, ultraviolet light resistance, solar
reflectance and emittance, tensile strength, water and fire
resistance, wind uplift, elongation and thermal expansion, dynamic
puncture resistance and resistance to rooftop contaminants such as
acid rain and air pollution. Exposure to extreme environments,
ultraviolet rays and thermal stresses age the useful life of roof
membrane systems.
[0006] Roof membrane systems are either mechanically fastened,
ballasted, heat welded or fully adhered with adhesives and
solvents. Membranes are both un-reinforced and reinforced with
polyesters or fiberglass for strength and dimensional stability and
available in a range of thickness from 45 mils to 90 mils. In the
roofing industry, thicker roof membranes are considered more
durable.
[0007] Flexible roof membranes are attached to the roof using one
of three methods. Ballasted roof membranes require that the
membrane material be laid directly over roof insulation or the roof
deck and attached at the perimeter and held in place by gravel
ballast or pavers. This system offers a low installation cost.
However, the system is restricted by the weight that the roof deck
is designed to support. In addition, the ballast material must be
removed to locate leaks, making repairs time consuming and costly.
In a second method, fully-adhered roof membranes require that the
roof membrane be adhered to the roof with contact adhesive. This
lightweight system yields high wind resistance and can be used with
most deck types. However, fully adhered roof systems depend on the
roof insulation to which they are adhered for wind uplift
resistance. Roof pads are also often required in high traffic areas
to prevent the compression of insulation, delamination of
insulation facers, and general damage to the membrane, such as
punctures and tears. In a third method, mechanically-attached roof
membranes are attached to steel and wood decks with fasteners.
[0008] The Environmental Protection Agency's ENERGY STAR.RTM. Roof
Products Program has established a minimum standard that requires
low-slope reflective roof products to have an initial solar
reflectance of at least 65 percent, and a reflectance of at least
50 percent after three years of weathering to be considered a `Cool
Roof`, energy efficient or high performance roof. Cool Roofs
typically incorporate bright white membranes that keep moisture out
while reflecting ultraviolet and infrared radiation, protecting the
underlying insulation and roofing substrate from deterioration.
These Cool Roof systems reduce building energy consumption by up to
40 percent, improve insulation performance to reduce winter heat
loss and summer heat gain and can potentially reduce HVAC equipment
capacity requirements. The Cool Roof reflects light and heat away
from the roof deck to assist with maintaining low air conditioning
loads and is considered an energy efficiency measure. Reflecting
light off the roof membrane results in lower lifetime membrane
temperatures and lengthen the life of the roofing system. The
success of sustainability initiatives such as the U.S. Green
Building Council's LEED rating system, have encouraged the roofing
industry to develop cool roof systems that meet or exceed
requirements for the U.S. EPA's ENERGY STAR.RTM. label for roofing
membranes.
[0009] The term "photovoltaic" is derived from the root words
"photo", meaning light, and "voltaic", meaning electricity.
Sunlight, the common power source for photovoltaic systems, is
composed of photons. The amount of energy in a photon is
proportional to the frequency of its light. When photons strike a
photovoltaic cell, the photons are either reflected or absorbed.
When a photon is absorbed, its energy is transferred to an atom of
the cell, where an electron leaves its normal position associated
with that atom and moves into a current. A portion of the energy
created is electrical, while another portion is thermal in
nature.
[0010] Photovoltaic cells react to different wavelengths of light
as a function of their material composition. Common photovoltaic
cell materials include: single crystalline silicon, polycrystalline
silicon and amorphous silicon, gallium arsenide, copper indium
diselenide, cadmium telluride, dye-sensitive and nano-technologies.
In addition, photovoltaic cells, laminates and modules can be
composed of two or more layers of different photovoltaic materials
with different wavelengths and bandwidth sensitivities to yield
improved energy conversion efficiencies.
[0011] When exposed to light, photovoltaic cells increase in
temperature, which affects each photovoltaic cell materials' energy
conversion efficiency in a unique manner. This is measured and
known as the Installed Nominal Operating Cell Temperature (INOCT).
For example, the efficiency of the crystalline silicon solar cell
strongly depends on its operating temperature and the efficiency of
the amorphous is less affected by its operating temperature.
Accordingly, thin film and flexible amorphous silicon systems have
been commercially accepted and flush mounted to membrane roof
systems. U.S. Pat. No. 4,860,509 and U.S. Patent Publication No.
2005/0072456 teach examples of flexible, photovoltaic material
roofing assemblies, adhered to a single-ply roofing membrane. In
the field, however, flexible amorphous silicon cell temperatures
have been documented to exceed 77.degree. C. (170.degree. F.).
Canadian Patent No. 2,554,494 provides an example of the use of
crystalline photovoltaic cells, in a layered fashion that includes
a base, flexible membrane layer, a semi-rigid support layer, the
photovoltaic layer and a protective layer forming a unitary
structure to be adhered directly to the roof. Each of these
photovoltaic membrane systems, however, allows the transmission of
heat from the photovoltaic cells to the building structure,
limiting the operative efficiency and life of the photovoltaic
cells and damaging the structural materials of the building and its
protective envelope system.
[0012] In the field, it is known in the photovoltaic community that
for each degree Celsius that a crystalline photovoltaic cell
increases over its standard test conditions (STC) rated
temperature, its performance goes down by .05% of its rated power.
Additionally, when photovoltaic cells are integrated into an
insulated roof system, there is little opportunity for heat loss
off the backside of the modules and this heat is transferred into
the building envelope.
[0013] Most crystalline silicon based PV arrays exhibit a relative
efficiency temperature sensitivity of 0.5%/1.degree. C. It is
estimated that thin film amorphous silicon and cadmium arrays,
although not as well documented due to their newness in the field,
exhibit less than half of the performance temperature sensitivity
of crystalline photovoltaic arrays. SANDIA National Laboratory
conducted a study that states that, "maintaining an open rack air
flow results in 20.degree. C. reduction in average operating
temperature, a nearly a 10% greater amount of annual energy (for
crystalline silicon), and an untold increase in life expectancy
compared to direct mounted arrays on an insulated roof surface."
Unfortunately, photovoltaic specialists have focused on the
photovoltaic's INOCT and have not addressed the architectural
impact of the increase of cell temperature on the roof system
beneath, the heat transfer impact on the buildings thermal
performance or the integrity of the building envelope.
[0014] Since the late 1980's, building integrated photovoltaic
(BIPV) technology and systems have been developed as part of a
movement towards whole building design and the efficient,
sustainable use of resources. The objective of BIPV technology is
to have one system that serves as the protective building envelope
and also generates electric power for use within the building in
the form of electric roof membranes, electric windows and glazing,
electric awnings, electric roof tiles, electric standing seam metal
roofing and the like. U.S. Pat. No. 6,553,729 and U.S. Pat. No.
6,729,081 teach examples of photovoltaic modules that are adhered
directly to a roof, wall or other portion of the building structure
using an adhesive. These photovoltaic systems generate on-site
distributed electric power that will offset building electrical
loads, decrease building electrical demand, put less demand stress
on the local utility transmission system, allow surplus power to be
fed back into the utility grid and may provide continuous power
supply during utility grid outage.
[0015] Photovoltaic membrane roof systems installed on low-sloped
roofs may be attached to the roof using mechanical fasteners,
ballast or adhesives. As the photovoltaic cell heats up, thermal
energy is trapped behind its surface, against the roof membrane,
insulation board and deck beneath the photovoltaic cell. Over time,
the photovoltaic system effectively stresses and ages the building
system underneath establishing a core physical incompatibility of a
direct interface between the two systems. Accordingly, prior art
systems that directly attach photovoltaic systems to roof decks
tend to reduce the performance life of the building materials by
elevating temperatures in the building envelope system. Elevated
temperatures accelerate and increase the degradation rates of most
materials. A common rule of thumb for polymers states that the
material life expectancy is reduced by half for each 10.degree. C.
rise in average temperature.
[0016] Photovoltaic systems mounted directly onto the building
envelope trap heat into the roof deck creating a series of hot
spots or heat islands on the roof which not only stresses and
accelerate the aging of the roof membrane and deck underneath but
negatively affecting the building's energy system. The trapped
thermal energy can result in greater heat transfer to the building
interior and produce a greater demand for air conditioning, which
results in a strain on both operating costs and the electric power
grid. Such systems further inhibit the ability of the roof
insulation to work optimally, in effect requiring that air
conditioning loads increase, due to the photovoltaic system. This
is inconsistent with the objective of using the photovoltaic
system.
SUMMARY
[0017] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key aspects or essential aspects of the claimed subject matter.
Moreover, this Summary is not intended for use as an aid in
determining the scope of the claimed subject matter.
[0018] A photovoltaic membrane system is provided for use on a
building and, optionally, incorporated into the building envelope.
It is a low profile, lightweight, photovoltaic integrated membrane
system that inhibits the transfer of heat from the photovoltaic
cells to the building envelope or interior building materials and
space, without trapping the thermal energy behind the photovoltaic
cell, laminate or module.
[0019] One or more photovoltaic cells, laminates or modules are
provided at an upper layer of the system. A thermal barrier is
disposed between the one or more photovoltaic cells and a
structural member of the building, such as a roof deck. The thermal
barrier is positioned to isolate the one or more photovoltaic
modules from the building envelope. The thermal barrier may be
provided as a series of wedge shapes, incorporated within the
membrane system, sloped and spaced in rows, in a manner to optimize
the electrical performance of the photovoltaic membrane assembly
for the building. An air channel assembly may be disposed between
the one or more photovoltaic cells, laminates or modules and the
thermal barrier to ventilate heated air from beneath the one or
more photovoltaic cells away from the system and the building.
[0020] In one aspect, the thermal barrier is formed from a light
weight material that substantially inhibits thermal transmission
from the one or more photovoltaic modules to the building envelope.
A roof membrane layer may be disposed between the one or more
photovoltaic modules and the roof deck. A layer of roofing membrane
may be disposed between the thermal barrier and the roof deck.
Another aspect sandwiches the thermal barrier between layers of
roofing membrane. Still another aspect may simply dispose a layer
of roofing membrane between the one or more photovoltaic modules
and the thermal barrier.
[0021] An air channel assembly may be disposed between the one or
more photovoltaic modules and the thermal barrier, be part of the
photovoltaic module, or be provided as part of the thermal barrier.
The air channel assembly may be provided to have at least one air
channel that is positioned to direct heated ambient air within the
air channel assembly away from the photovoltaic system.
[0022] The system may be provided in an assembled form that may be
permanently or removably coupled with the envelope of a building.
In another aspect, the system may be provided in component parts to
be assembled at the building during installation. In one aspect,
roofing membrane may be provided with markings to indicate where
photovoltaic modules and thermal barriers should be located with
respect to the roofing membrane, prior to installing the system on
the building.
[0023] Also contemplated is an isolation mount that includes an
isolator body, which may be a thermal barrier, a first membrane
adjacent to a lower surface of the body, and a second membrane
extending over the isolator body that includes a peripheral margin
that is at least partially sealed or adhered to the first membrane.
At least one connector is supported by the isolator body and at
least one fastener extends through the second membrane to secure
the connector to the isolator body. The connector may include a
mounting rail, posts, or an air channel assembly. Alternatively,
the fasteners may be captive and attached to the membrane without
penetrating the membrane. For example, the fastener may be
induction welded to the second membrane.
[0024] The isolation mount may include a washer element interposed
between the isolator body and the second membrane, where the
fasteners extend from the washer element. The isolation mount may
also include a third membrane interposed between the isolator body
and the washer element.
[0025] A photovoltaic module for use on the roof of a building also
is provided for in the present application. The photovoltaic module
includes at least one isolator body, a first membrane adjacent to a
lower surface of the body, and a second membrane extending over the
isolator body that includes a peripheral margin that is at least
partially sealed to the first membrane. A plurality of connectors
are supported by the isolator body and at least one photovoltaic
cell is mounted to the connectors. A roof deck panel may be
included that supports one or more modules.
[0026] A photovoltaic roofing system for use on the roof of a
building also is contemplated. The photovoltaic roofing system may
include at least one isolator body, and a plurality of isolator
bodies. A first membrane is disposed between the isolator bodies
and the building. At least one second membrane extends over the
isolator bodies and is adhered to the first membrane. A plurality
of connectors are supported by the isolator bodies and at least one
photovoltaic cell is mounted to the connectors. The system may
further include a roof deck that is disposed between the first
membrane and the building.
[0027] Also contemplated is a method for deploying a photovoltaic
roofing system on the roof of a building. The method comprises
pre-assembling a first membrane and a second membrane to form a
cavity. The second membrane includes a plurality of connectors for
supporting a solar panel. The first membrane is secured to the roof
and the cavity is filled with foam. The foam is injected into the
cavity to form an isolator body. A photovoltaic cell may then be
mounted to the connectors.
[0028] These and other aspects of various embodiments of the
disclosed technology will be apparent after consideration of the
Detailed Description and Figures herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Non-limiting and non-exhaustive embodiments of the disclosed
technology are described with reference to the following figures,
wherein like reference numerals refer to like parts throughout the
various views unless otherwise specified.
[0030] FIG. 1 depicts exemplary embodiments of the photovoltaic
membrane assembly as it may be coupled with the envelope of a
building;
[0031] FIG. 2A depicts a preassembled embodiment of the
photovoltaic membrane system;
[0032] FIG. 2B depicts modular components of the photovoltaic
membrane system before their installation on a building;
[0033] FIG. 3A depicts a partially exploded view of the integrated
photovoltaic membrane system with an air channel assembly;
[0034] FIG. 3B depicts a partially exploded view of the
photovoltaic membrane system without an air channel assembly;
[0035] FIG. 4A depicts a cut-away, side elevation view of the
photovoltaic membrane system depicted in FIG. 3A;
[0036] FIG. 4B depicts a cut-away, side elevation view of the
photovoltaic membrane system depicted in FIG. 3B;
[0037] FIGS. 5A-5D depict various embodiments of air channels that
may be incorporated with the photovoltaic membrane system;
[0038] FIGS. 6A-6D depict various different embodiments of thermal
barriers that may be used with the photovoltaic membrane
system;
[0039] FIG. 7A depicts one manner in which the thermal barrier of
the photovoltaic membrane system can be coupled with a
building;
[0040] FIG. 7B depicts another manner in which the thermal barrier
of the photovoltaic membrane system can be coupled with a
building;
[0041] FIG. 7C depicts still another manner in which the thermal
barrier of the photovoltaic membrane system can be coupled with a
building;
[0042] FIGS. 8A-8C depict various different embodiments of thermal
barriers and thermal barrier units that may be used with the
photovoltaic membrane system;
[0043] FIG. 9 depicts an exploded perspective view of a
photovoltaic roofing system that includes an isolation mount
according to an exemplary embodiment;
[0044] FIG. 10 is an exploded perspective view depicting an
embodiment of an isolation mount;
[0045] FIG. 11A depicts a perspective view of an isolation mount
according to another exemplary embodiment;
[0046] FIG. 11B depicts an exploded perspective view of the
isolation mount depicted in FIG. 11A;
[0047] FIG. 12 depicts a partial perspective view of an isolation
mount for a thin film type solar panel according to an exemplary
embodiment;
[0048] FIG. 13 is an enlarged partial perspective view of the
isolation mount shown in FIG. 12;
[0049] FIG. 14 is a partial perspective view of an isolation mount
for use with thin film type solar panels according to another
exemplary embodiment;
[0050] FIG. 15 illustrates an exemplary flat pattern for a second
membrane;
[0051] FIG. 16 is a side view illustrating a captive fastener
configuration for mounting solar panels to an isolation mount;
[0052] FIG. 17 is an exploded side view of the captive fastener
configuration shown in FIG. 16;
[0053] FIG. 18 is an exploded partial perspective view illustrating
the installation of washer elements for use with the captive
fastener configuration shown in FIGS. 16 and 17;
[0054] FIG. 19 is a partial perspective view of the isolator body
with washer elements shown in FIG. 18;
[0055] FIG. 20 is top plan view of multiple photovoltaic modules
pre-assembled to a membrane sheet;
[0056] FIG. 21 is side view in elevation of the multi module
assembly shown in FIG. 20;
[0057] FIG. 22 is a top plan view of an anchor for mounting a
membrane sheet to the ground;
[0058] FIG. 23 is a side view in elevation of the anchor shown in
FIG. 22; and
[0059] FIG. 24 is a partial perspective view of an isolation mount
including a wire management sleeve.
DETAILED DESCRIPTION
[0060] Embodiments are described more fully below with reference to
the accompanying figures, which form a part hereof and show, by way
of illustration, specific exemplary embodiments. These embodiments
are disclosed in sufficient detail to enable those skilled in the
art to practice the technology of the present application. However,
embodiments may be implemented in many different forms and should
not be construed as being limited to the embodiments set forth
herein. The following detailed description is, therefore, not to be
taken in a limiting sense.
[0061] In one aspect, the photovoltaic membrane system 10 disposes
an isolator body, which may be in the form of a thermal barrier 12,
between one or more photovoltaic cells 14 and the roof deck 16 of a
building 18 to which the photovoltaic membrane system 10 is
coupled. The thermal barrier 12 of the photovoltaic membrane system
10 serves as a physical separation barrier. Specifically, thermal
barrier 12 is positioned to significantly limit heat transfer from
the photovoltaic cells 14 to the building 18, its interior spaces,
and its envelope that may include: a protective roof membrane 20,
insulation 22, and roof deck 16. The thermal barrier 12 may also be
formed from materials that embody fire resistance properties to
provide additional protection to the roof of the building 18.
[0062] The thermal barrier 12 may be formed from a variety of
materials that include: thermoset polymers; thermoplastics;
extruded or molded copolymers; foam; rigid closed cell
polyisocyanurate foam core; gypsum glass mat board; fiberglass;
fiber board; vapor retardant; slipsheet; flame retardant; cap
sheet; or some combination of the aforementioned materials. Each of
the aforementioned materials possess similar qualities that
individually or in combination retard the transfer of heat and can
withstand wide variations in temperature and weather conditions
present in most climates.
[0063] With reference to FIGS. 6A-6D, the thermal barrier 12 may be
shaped to resemble a low-profile, flat wedge or low-profile tapered
wedge. The exterior perimeter walls of the thermal barrier may be
aerodynamically shaped to direct airflow and minimize wind forces
on the photovoltaic membrane system 10. One or more peaks 24 and
valleys 26 may be formed into the thermal barrier 12 to provide a
profile resembling that depicted in FIG. 6D. The peaks 24 of the
thermal layer 12 are formed to support the photovoltaic cells 14,
angled and sloped to increase the electrical performance of the
solar cells, whereas the valleys 26 form channels that permit the
flow of fluids, such as air or water between one or more
photovoltaic cells 14 and the thermal barrier 12. Accordingly, the
spaces formed between the one or more photovoltaic cells 14 and the
valleys 26 of the thermal barrier 12 will promote thermal isolation
between the photovoltaic cells 14 and the building 18. Such spaces
will form insulative barriers utilizing natural convection air
flow. The warmed ambient air will escape into the environment or
may be directed into conduits that collect the warm air for uses
within the building 18. In addition or in the alternative, pipes
may be mounted in the valleys 26 such that the valleys 26 may be
used as a heat exchanger with water or air pipes.
[0064] With reference to FIGS. 8A-8C, it is contemplated that the
thermal barrier could be provided as a plurality of separate
thermal barrier units 12'. In one aspect, the thermal barrier units
12' may be provided as low-profile blocks, having little or no
slope to their shape, such as those depicted in FIG. 8A. In another
aspect, the thermal barrier units 12' may be shaped to take the
form of individual tapered wedges, such as those depicted in FIG.
8C. While such thermal barrier units 12' may be used as the sole
thermal barrier 12, they may also be used in combination with the
previously described thermal barrier 12, such as depicted in FIG.
8B. In any of the contemplated arrangements that use the thermal
barrier units 12', air channels (such as those previously described
are provided between the thermal barrier units 12' once they are in
their final assembly position.
[0065] With reference to FIGS. 7A-7C, the thermal barrier 12 may be
coupled with the roof of the building 18 in various different
manners. For example, FIG. 7A depicts one manner in which he
thermal barrier 12 may be coupled with a roof by positioning the
thermal barrier 12 directly on a roof membrane surface 20. FIG. 7B,
depicting an alternate embodiment, demonstrates that the thermal
barrier 12 may be placed between two or more layers of roof
membrane material 20. In still another alternate embodiment, FIG.
7C demonstrates that the thermal barrier 12 may be placed under a
layer of roofing membrane 20, onto the roof deck 16. In one
particular embodiment, it is envisioned that the thermal barrier 12
may be provided as interlocking preformed insulation boards that
are coupled with the roof, beneath the roofing membrane 20. Also,
optional fire resistant layers may be included. The fire resistant
layers may include for example and without limitation materials
such as aluminum foil with fiberglass scrim, a synthetic film, or
treated gypsum board, such as DensDeck.RTM. available from
Georgia-Pacific.
[0066] The photovoltaic cells 14 of the photovoltaic membrane
system 10 are formed into arrays shaped as rows. Specifically,
low-profile, flat solar panels may be spaced in rows closely
adjacent one other. Alternatively, low-profile, tapered wedge shape
panels are laid out in rows at a predetermined space between rows
to avoid one row of solar panels from shading the next row to
optimize electrical performance.
[0067] The thermal barrier 12 may be provided with a reflective
layer 28 to enhance the thermal protection afforded by the thermal
barrier 12. In one aspect, the reflective layer 28 may be provided
in the form of a bright white reflective surface or reflective
metal material. By providing such a reflective layer 28, heat
radiated from the photovoltaic cell 14 is reflected back toward the
photovoltaic cell 14, away from the building 18. Where an air
channel assembly 30 is provided, the reflected heat may be passed
away from the building 18 and the photovoltaic system through the
air channel assembly 30.
[0068] In one aspect, the thermal protection afforded by the
thermal barrier 12 may be increased by providing an air channel
assembly 30. With reference to FIGS. 3A, 4A and 5A-5D, an air
channel assembly 30 may be provided between the photovoltaic cells
14 and the thermal barrier 12. In one embodiment, the air channel
assembly 30 is provided to form a physical air space between the
photovoltaic cells 14 and the thermal barrier 12. Air within the
air channel assembly 30 serves as an insulative layer that inhibits
the transfer of heat from the underside of the photovoltaic cells
14 to the thermal barrier 12. However, in another aspect, the air
channel assembly 30 is provided with one or more openings 32 that
promote the expulsion of heated air away from the photovoltaic
membrane system 10 and the building 18.
[0069] Generally, the air channel assembly 30 may be formed to
provide protective air gaps, cavities or spaces that allow
ventilation and circulation behind the photovoltaic cells 14. The
specific configuration of the channels within the air channel
assembly 30 may vary from one embodiment to another to accommodate
particular design considerations. Various design considerations
may, for example call to confuse, deflect and reduce wind uplift
forces that engage the photovoltaic membrane system 10. Heated air
within the air channel assembly 30 will tend to dissipate through
the openings 32 naturally by convection. In the end, the
combination of the air channel assembly 30 with the thermal barrier
12 will increase the electrical output of the photovoltaic cells 14
by keeping them cooler. Perhaps more importantly, however, these
structures will help alleviate the damaging effects of heat being
trapped against one or more components to the building envelope,
such as roof membrane systems 20.
[0070] In one aspect, thermal energy may also be captured from the
photovoltaic cells 14 using the air channel assembly 30. Rather
than expelling the heated air from the air channel assembly
openings 32, the thermal energy within the air channel assembly 30
may be redirected for use within the building energy system. For
example, heated air may be directed into the building 18 during
winter months. In another aspect, the heated ambient air may be
used as a heat exchanger to pre-warm water for use within the
building 18.
[0071] It is contemplated that the photovoltaic system 10 may be
attached to a roof membrane material 20 in the factory or on a
jobsite in the field. For example, the rows of photovoltaic cells
14 may be pre-attached to a roof membrane material 20 in a strip
format. Providing photovoltaic membrane strips of this nature will
limit installation decisions at job sites by roofers and speed the
installation of the system. However, in various situations,
preassembly may not be preferred, including custom roofing
applications. In such instances, roofing membrane material 20 may
be pre-marked with indelible ink, paint, and adhesive or scored to
provide direction as to where to attach the photovoltaic cells
14.
[0072] In attaching the photovoltaic membrane system 10 with a
roof, a variety of attachment methods may be employed that are
currently used for installing traditional roof membrane systems.
For example, the system may be coupled with the roof using
mechanical fasteners. Other techniques, such as heat-welding
methods, glues, pressure-sensitive or peel-and-stick adhesives may
be used. In still other embodiments, the photovoltaic membrane
system 10 may be ballasted to the top surface of the roofing
membrane 20, insulation board 22 or fastened directly to the roof
deck 16.
[0073] It is contemplated that the photovoltaic membrane system 10
may be provided as a permanent installation or made a part of a
temporary, removable photovoltaic system. Specifically, the
photovoltaic membrane system 10 may be fully integrated as the roof
membrane layer 20 or with one or more roof membrane layers 20 of
the building envelope. Where provided in a removable fashion, the
photovoltaic membrane system 10 may be ideal for use as a portable
power supply or removable personal property equipment for power
purchase agreements. Various possibilities for temporary attachment
include the use of ballasting techniques or anchoring the system in
place between the rows and along perimeter PVC pipes or other
polymer extrusion. The system may also be anchored over the rows.
It is further contemplated that other fastening methods may be
used, including the use of grommets attached with cables or guy
wires to perimeter parapet walls or to anchors in roof.
[0074] It is further contemplated that the photovoltaic membrane
system could be used in various applications beyond buildings. For
example, the system could be deployed on the ground, such as on a
landfill, mining site, or waste disposal cell. The system could be
adhered to the geomembrane of a landfill. Geomembranes are made of
various materials. Some common geomembrane materials are EPDM
rubber (ethylene propylene diene Monomer, Low-Density Polyethylene
(LDPE), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC),
Polyurea and Polypropylene (PP). Another type of geomembrane is
bituminous geomembrane (such as Environap), which is actually a
layered product of glass and bitumen-impregnated non-woven
geotextile. The geomembrane may be water tight or water
permeable.
[0075] FIG. 9 depicts an isolation mount 105, which may be used to
support a photovoltaic cell 114 on a roof surface 116. The
isolation mount 105 and the photovoltaic cell 114 may be combined
to form a photovoltaic module for use on the roof of a building.
Isolation mount 105 includes an isolator body 112, a first, or
lower, membrane 122 that is adjacent to the lower surface of
isolator body 112, and a second, or top, membrane 120 that extends
over the isolator body 112. Second membrane 120 includes a
peripheral margin 123 that is at least partially sealed to first
membrane 122. The membranes may be sealed or adhered to each other
by hot air weld, dielectric high radio frequency welding, water
resistant solvent-based adhesive, and the like. Ideally, the
peripheral margin 123 forms a hermetic seal or a waterproof seal
between first membrane 122 and second membrane 120. The membranes
may be comprised of water resistant materials such as
thermoplastics (TP), thermosets (TS), thermoplastics olefins (TPO),
polyvinyl chloride (PVC), chlorinated polyethylene (CPE),
chlorosulfanated polyethylene (CPSE), keytone ethylene ester (KEE),
ethylene propylene diene rubber (EPDM), tri-polymer alloy (TPA),
combinations thereof, and the like. The membranes, particularly the
upper membrane that extends over the isolator body, may be formed
by, for example, heating the membrane material and vacuum forming
over the isolator body or similarly shaped mold (i.e.
thermoforming). The membrane may be a preformed shell formed by
injection molding or thermoforming, for example.
[0076] Alternatively, the upper membrane may be formed by folding a
flat pattern 600, as illustrated in FIG. 15, and hot air welding
the flaps in the folded configuration. Pattern 600 includes a
central portion 602, a back portion 604, and right and left side
portions 606 and 608 respectively. In order to form the top
membrane the side portions 606, 608 are folded down along lines 601
and 603 respectively. Back portion 604 is folded down along line
605. Flaps 610 and 612 are then folded along lines 607 and 609
respectively at which point flaps 610 and 612 may be attached to
side portions 606 and 608. As explained above, the flaps may be
heat, induction, or radio frequency (RF) welded or otherwise
adhered to the side portions. It can be appreciated that once
folded the flat pattern forms a wedge shaped top membrane as
described herein with respect to the various embodiments.
Peripheral portions 623'-623''' comprise a peripheral margin that
may be used to attach the top membrane to the roof membrane or the
bottom membrane of the isolation mount.
[0077] Photovoltaic cell 114 may be adhered to the top membrane 120
with adhesive, such as adhesive tape or painted adhesive.
Photovoltaic cell 114 may also be attached to the top membrane 120
with cooperative hook and loop material such as Velcro.RTM.. In
this instance, however, isolation mount 105 includes a pair of
connectors in the form of mounting rails 130(1) and 130(2), which
are supported by isolator body 112. Mounting rails 130 may in turn
support a photovoltaic cell 114. Mounting rails 130 may comprise,
for example, metal or plastic and may be molded, machined, or
extruded. Various connectors may be employed, such as rails, posts,
air channel assemblies (see above), cooperative hook and loop
material, and the like. The mounting rails are also adapted to
secure the photovoltaic cell 114 to the isolation mount 105. In
this embodiment, a plurality of fasteners 140 extend through
isolator body 112 and second membrane 120 in order to secure
mounting rails 130 to the isolation mount. Washers 142 may be used
to distribute clamping forces generated by fasteners 140 across a
larger area of the lower surface of isolator body 112. Fasteners
140 may extend through holes 125 formed in the second membrane 120
or the fasteners may pierce through membrane 120. Fasteners 140,
holes 125, and washers 142 may be applied with caulk or the like to
seal the leak path formed by the device. Similarly, isolator body
112 may be preformed with holes, or as shown here, the fasteners
may pierce through the isolator body 112. In this case, where the
isolator body 112 is a thermal barrier, the body may be formed of a
foam material conducive to piercing with a suitable fastener.
Fasteners 140 may engage the mounting rails 130 directly, as with
threads, or the fasteners 140 may cooperate with mating fasteners
or nuts 144.
[0078] Depending on the application, isolator body 112 may be
formed from various materials. For example, as shown in FIG. 9
isolator body 112 is comprised of a thermal barrier material for
use with photovoltaic cells as described above. While some of the
embodiments are described with respect to photovoltaic cells, the
isolation mount may be used to mount other equipment. For example,
isolator body 112 may be formed of a vibration dampening material
for mounting reciprocating equipment. Examples of suitable
materials for the isolator body include, for example and without
limitation, faced or unfaced insulation board, expanded polystyrene
(EPS), polyisocyanurate foam, fiber glass insulating board,
plywood, oriented strand board (OSB), gypsum board, DensDeck.RTM.,
wood fiber, fiberglass board, coverboard, plastic, plastic blend
materials, and the like. The isolator body may also be formed of a
two part liquid or expanding spray foam that is injected between
the first and second membranes. Example spray foams that may be
used include polyisocyanurate spray foam, closed-cell polyurethane
spray foam, open-cell polyurethane spray foam, phenolic spray foam,
icynene spray foam or other spray foam.
[0079] It should be appreciated that a photovoltaic roofing system
110 is also contemplated, which employs an isolation mount, such as
isolation mount 105 described above. With continued reference to
FIG. 9, roofing system 110 could include a plurality of isolator
bodies 112, wherein the lower membrane 122 extends beneath the
isolator bodies and functions as a roof membrane. A plurality of
second membranes 120 may be disposed over each of the isolator
bodies. Alternatively, a single upper membrane 120 could extend
over the plurality of bodies. It is further contemplated that such
a multiple isolator body construction could be preformed and folded
or rolled for convenient deployment on a roof surface 116.
Alternatively, the first and second membranes could be adhered to
each other without the isolator body. In such a case the membranes
could be deployed on the roof and thereafter injected (i.e.
inflated) with foam or two part liquid as explained above. The
roofing system may also include roof deck panels. The panels may be
formed from materials including metal, fibrous cement, gypsum,
cementitious wood fiber, OSB, lightweight insulating concrete
decks, and the like.
[0080] FIG. 10 depicts another embodiment of an isolation mount
205, which is similar to the embodiment described above with
respect to FIG. 9. However, in this embodiment isolation mount 205
includes washer element 150 interposed between isolator body 212
and second membrane 220. Optionally, a third membrane 224 may be
interposed between isolator body 212 and washer element 150. In
this embodiment, fasteners 140 extend from washer element 150 and
through second membrane 220 and through mounting rails 130. As
shown in this case, fasteners 140 engage mating fasteners (nuts)
144 thereby developing clamping force to secure mounting rails 132
to isolation mount 205. As an option, additional washers 142 and
146 may be used as shown. In this case washer element 150
distributes the clamping force over a relatively large area of
second membrane 220 providing resistance to wind uplift and damage
to the mount. Washer element 150 may be comprised of faced or
unfaced insulation board, expanded polystyrene, polyisocyanurate
foam, fiber glass insulating board, plywood, oriented strand board,
gypsum board, DensDeck.RTM., wood fiber, fiberglass board,
coverboard, thermoformed, compressed or injection molded plastic
and plastic blend materials, to name a few. It should be
appreciated that the construction of this embodiment may be
incorporated into a photovoltaic module and/or photovoltaic roof
system as explained above with respect to FIG. 9.
[0081] FIGS. 11A and 11B depict yet another embodiment of an
isolation mount 305. Isolation mount 305 is similar to that as
described above with respect to FIG. 9. In this case, however, each
connector 330(1)-330(4) includes a mounting post 332. Mounting
posts 332 may be comprised of for example, extruded plastic or
pipe. Each mounting post 332 extends through an opening 325 formed
through second membrane 320. Opening 325 may be formed by extruding
a cylindrical portion upwardly from membrane 320. For example,
openings 325 may be formed by a die-punch operation including
heating the membrane prior to punching. Fasteners 140 extend
through washers 142, isolator body 312, and engage posts 332. Posts
332 are further secured to the isolation mount with connector seals
334, which include a flange portion 331. Connector seals 334 may be
formed in a similar manner to that as described above for openings
325. The flange portions 331 of connector seals 324 are sealed to
second membrane 320. Connector seals 334 are also sealed to posts
332 with a suitable water resistant caulk, such as for example,
polyurethane caulk, non-shrink grout, sealing mastic, silicone,
glue, and the like. Optionally, a tension or draw band 336 may be
secured around the connector seal and post in order to further
inhibit ingress of water or other fluid into the isolation mount.
As above, it should be appreciated that the construction of this
embodiment may be incorporated into a photovoltaic module and/or
photovoltaic roof system as explained above with respect to FIG.
9.
[0082] FIG. 12 illustrates an exemplary embodiment of an isolation
mount 405 for use in a system 410 using thin film or laminate type
solar panels 414. Laminate type solar panels from manufacturers
such as UniSolar.RTM. often include adhesive 425 for adhering the
panel directly to the membrane material. However, there is concern
that as the solar panel heats up, as described above, the adhesive
bond may slip or weaken. Accordingly, in order to help ensure the
attachment of the solar panel 414 to the top membrane 420,
connectors in the form of fastener clips 430 are integrated into
the isolation mount 405. With further reference to FIG. 13 it can
be appreciated that the clips 430 are positioned on a corresponding
boss 432 that is elevated above the top membrane 420. The boss 432
is raised sufficiently to provide clearance 426 for typical
adhesive material 425 used to adhere the solar panel 414 to the
membrane 420. Each clip 430 is spaced slightly above its
corresponding boss 432 to provide clearance for an edge of the
solar panel 414 to slide between the top of the clip 430 and boss
432 as shown in FIG. 12. One ordinarily skilled in the art will
recognize that clip 430 and boss 432 could comprise separate pieces
or be integrally formed, such as by injection molding.
[0083] The isolation mount 405 also includes a fitting 450 which
allows any water or air that may accumulate within the isolation
mount 405 to drain therefrom. Fitting 450 extends through the side
of the top membrane into the interior of the mount. The fitting 450
may include a screen or other filtering element (see FIG. 13), such
as sintered metal or plastic, to prevent the ingress of dirt and
insects, for example. Fitting 450 could also be a check valve to
allow air and water out but prevent air, water, and debris from
entering the isolator. It is contemplated that a similar fitting
450 could be implemented on any of the embodiments described herein
as desired. Moreover, fitting 450 could be used as an inlet to
inflate the isolation mount with spray foam as explained above.
[0084] FIG. 14 illustrates another exemplary embodiment of an
isolation mount 505 for use with thin film, laminate type, or
otherwise non-glass solar panels 514. In this embodiment the
laminate panels 514 are secured to the membrane by straps 530.
Straps 530 extend along the length of solar panels 514 and include
fingers 532 on each end that extend along a portion of the solar
panel's width. Straps 530 and fingers 532 are welded or otherwise
fastened to the adjacent membrane to form a pocket in order to help
secure solar panels 514 in position.
[0085] FIGS. 16 and 17 illustrate the attachment of fasteners 740
to membrane 720 according to another exemplary embodiment. In this
embodiment, fasteners 740 are captive with respect to washers 744.
Fasteners 740 are carriage bolts having a square shank which
engages a square hole 746 formed through washer 744, thereby
preventing rotation of the fasteners relative to washers 744.
Washers 744 are induction welded to membrane 720 without
penetrating the membrane. Each washer is bonded to the membrane
with an induction welder. The washers include a heat activated
adhesive. A suitable induction welder is produced by Sika.RTM.
Sarnafil.RTM. and marketed as the Rhinobond System.
[0086] The Rhinobond System is typically used to install only one
washer to the underside of a membrane. However, as shown in the
figures, two fasteners 740 and washers 744 are bonded to membrane
720; one on the top side one on the underside. With further
reference to FIGS. 18 and 19, the fastener on the top side of the
membrane may be used to attach solar panel mounting connectors,
while the fastener on the under side of the membrane is used to
anchor the solar panel and membrane to the isolator body. The
fastener 740 extending from the underside of the membrane 720 is
configured to extend through the isolator body where an additional
washer 742 may be used to distribute clamping forces generated by
fasteners 740 across a larger area of the lower surface of isolator
body 712. The Rhinobond System may be modified to help facilitate
welding two fasteners simultaneously by forming a hole in the
Rhinobond machine through the middle of induction coil. The hold
would allow the fastener to extend therethrough moving the
induction coil closer to the washers. The two fasteners may also be
installed in an offset arrangement such that the washer and
fastener on the top of the membrane is offset from the washer and
fastener on the bottom. In an offset arrangement the washers can be
welded to the membrane one at a time.
[0087] FIGS. 20 and 21 illustrate an alternative configuration for
preassembling multiple photovoltaic modules to a membrane sheet
820, similar to that shown above in FIG. 2A. The modules may be
folded and stacked onto or next to each other in an accordion
fashion. The sheet can be quickly pulled apart on the jobsite for a
cost effective installation. In this configuration, the modules are
preassembled on a standard roll of membrane material having a
length (L) and a width (W). For example the roll may be 100 feet
long and 8 feet wide. Modules may be preassembled to geomembrane
material and be installed as one unit to reduce onsite labor. FIGS.
20 and 21 illustrate attaching 48 solar panels 814 (4 on each
isolation mount 805) on isolator bodies to create one large
membrane that will cover an area approximately 100 feet.times.8
feet. This can be used as the watertight layer of the roof, as the
single ply membrane layer in a roof assembly to integrate multiple
photovoltaic units at one time, or as a solar geomembrane cap to
cover a landfill to inhibit water migration from the landfill into
the groundwater, streams, rivers etc. The membrane material may be
anchored to the ground using an anchor 900 as shown in FIGS. 22 and
23. Anchor 900 includes a washer 944 and a stake 940. The washer
944 is attached to the stake 940 with a suitable fastener 950 as
shown. The fastener engages a bent over portion 943 of stake 940.
Stake 940 also includes at least one barb 942, or as shown here a
plurality of barbs, operative to help retain the stake 940 in the
ground.
[0088] FIG. 24 illustrates an isolation mount 105 that includes a
wire management sleeve 107 attached thereto. The wire management
sleeve 107 could be adhered or heat welded to any one of the
isolation mount embodiments disclosed herein. The wire management
sleeve 107 is sized and configured to accommodate wire or conduit
103 associated with the photovoltaic cells.
[0089] The technology of the present application is applicable to
all photovoltaic technologies including but not limited to
individual cells or layered cells comprising of single crystalline
silicon, polycrystalline silicon and amorphous silicon, gallium
arsenide, copper indium diselenide, cadmium telluride,
dye-sensitive and nano-technologies. It is contemplated that one or
more embodiments may further incorporate the use of thin film and
organic photovoltaic technologies, developed as paint or film
coatings instead of separate photovoltaic cells, laminates or
modules.
[0090] Accordingly, the technology of the present application has
been described with some degree of particularity directed to the
exemplary embodiments. It should be appreciated, though, that the
technology of the present application is defined by the following
claims construed in light of the prior art so that modifications or
changes may be made to the exemplary embodiments without departing
from the inventive concepts contained herein.
* * * * *