US20100313928A1

US20100313928A1 - Photovoltaic Array With Array-Roof Integration Member

Info

Publication number: US20100313928A1
Application number: US12/483,022
Authority: US
Inventors: Douglas H. Rose; Carl LENOX
Original assignee: Individual
Current assignee: SunPower Corp
Priority date: 2009-06-11
Filing date: 2009-06-11
Publication date: 2010-12-16
Also published as: WO2010144226A1; US20160079911A1; US9716465B2

Abstract

One embodiment relates to a photovoltaic (PV) apparatus. The PV apparatus includes a plurality of photovoltaic modules arranged in an array and attached to a support structure which is attached to a roof. Each of the photovoltaic modules comprises a plurality of photovoltaic cells. A first array-roof integration member is attached to a first side of the array. The array-roof integration member covers a gap between the first side of the array and the roof. Another embodiment relates to a method of installing a photovoltaic apparatus upon a sloped roof. Another embodiment relates to a kit for mounting a photovoltaic apparatus on a roof. Other embodiments, aspects and features are also disclosed herein.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to photovoltaic systems installed on roofs.
2. Description of the Background Art
Photovoltaic cells, also referred to as “solar cells,” are well known devices for converting solar radiation to electrical energy. Photovoltaic cells may be packaged together in a photovoltaic module (“PV module”), which comprises a plurality of interconnected photovoltaic cells. A rigid frame may surround the solar cells of the PV module. A photovoltaic installation may include a PV array, which includes a plurality of interconnected PV modules. The PV array may be installed on a rooftop.

SUMMARY

One embodiment relates to a photovoltaic (PV) apparatus. The PV apparatus includes a plurality of photovoltaic modules arranged in an array and attached to a support structure which is attached to a roof. Each of the photovoltaic modules comprises a plurality of photovoltaic cells. A first array-roof integration member is attached to a first side of the array. The array-roof integration member covers a gap between the first side of the array and the roof so that the array appears integrated with the roof.
Another embodiment relates to a method of installing a photovoltaic apparatus upon a sloped roof. A support structure is attached to a roof, and a plurality of photovoltaic modules are attached to the support structure so as to form a photovoltaic array. A first array-roof integration member is attached to a first side of the photovoltaic array. The array-roof integration member covers a gap between the first side of the photovoltaic array and the roof so that the array appears integrated with the roof.
Other embodiments, aspects and features are also disclosed herein.
These and other features of the present invention will be readily apparent to persons of ordinary skill in the art upon reading the entirety of this disclosure, which includes the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top planar view of a solar panel on a roof with an array-roof integration member in accordance with an embodiment of the invention.

FIG. 2 is a side cross-sectional view of a solar panel on a roof with an array-roof integration member in accordance with an embodiment of the invention.

FIG. 3 is a front cross-sectional view of a solar panel on a roof with an array-roof integration member in accordance with an embodiment of the invention.

FIG. 4 is a top planar view of an array of solar panels on a roof with an array-roof integration member in accordance with an embodiment of the invention.

FIG. 5 is a top planar view of an array of solar panels on a roof with a plurality of array-roof integration members in accordance with an embodiment of the invention.

FIG. 6A is a front cross-sectional view of a solar panel or panels on an uneven roof structure with a conventional member.

FIG. 6B is a front cross-sectional view of a solar panel or panels on an uneven roof structure with an array-roof integration member in accordance with an embodiment of the invention.

FIG. 7 is a top planar view of a solar panel (photovoltaic module) in accordance with an embodiment of the invention.

The use of the same reference label in different drawings indicates the same or like components.

DETAILED DESCRIPTION

In the present disclosure, numerous specific details are provided, such as examples of apparatus, components, and methods, to provide a thorough understanding of embodiments of the invention. Persons of ordinary skill in the art will recognize, however, that the invention can be practiced without one or more of the specific details. In other instances, well-known details are not shown or described to avoid obscuring aspects of the invention.
Residential photovoltaic systems are most commonly mounted on roofs using a retrofit installation system (for example, a rail system or a non-rail system) which provides a uniform plane for the modules and allows air flow under the modules. Such a retrofitted system may be installed on an asphalt or composite shingle roof without the need to remove existing roofing material. Unfortunately, the retrofit installation makes the array look like it is a separate structure on top of the roof, and it also reveals visual imperfections in the roof.
An alternative system uses roof-integrated solar panels. For example, the SunTile™ system available from SunPower Corporation of San Jose, Calif. has the advantage of appearing built-into a roof. However, such roof-integrated systems are generally meant to be installed exclusively with concrete tile roofs, and such systems require either installation in new construction, or removing existing roofing materials for a retrofit installation. Furthermore, the integrated solar panels typically run at a higher temperature and thus with a lower conversion efficiency
The present application discloses the use of an array-roof integration member which is designed for asphalt or composite shingle roofs to provide a mechanism for visually integrating a solar array into a roof while allowing the mounting of the solar modules at conventional rail height. Advantageously, this permits adequate airflow under the solar panel array and lowers the cost of achieving the aesthetics of integrated solar panels for shingled roofs. Higher conversion efficiency is typically achieved versus integrated solar panels.
In FIGS. 1-3, a single solar panel is shown for purposes of simplicity in explanation. In practice, an array including a plurality of interconnected solar panels is installed on a roof, as shown, for example, in FIGS. 4-5.
FIG. 1 is a top planar view of a solar panel 104 on a roof 102 with an array-roof integration member 108 in accordance with an embodiment of the invention. The solar panel 104 is installed on the roof using panel supports 106. In one implementation, the panel supports 106 may comprise a rail system, for example. In other implementations, the panel supports 106 may comprise non-rail systems, such as, for example, the smart mount system available from SunPower Corporation of San Jose, Calif. or other non-rail systems.
FIG. 2 is a side cross-sectional view of a solar panel 104 on a roof structure 102 with an array-roof integration member 108 in accordance with an embodiment of the invention. This view shows a layer of roof shingles 202 on the roof structure 102. The array-roof integration member 108 is affixed to the frame of the solar panel 104 and may also be affixed to the roof 102.
In accordance with an embodiment of the invention, as shown in FIG. 2, the array-roof integration member 108 may be a flexible member so as to be configurable to a curved profile. In accordance with another embodiment, the array-roof integration member 108 may be configured with a surface color which is selected from a set of surface colors so as to visually match or be visually complementary to a surface color of the roofing material. In another embodiment, the array-roof integration member 108 may be a flexible member and also configured with a surface color which is selected from a set of surface colors so as to visually match or be visually complementary to a surface color of the roofing material.
As further shown in FIG. 2, the array-roof integration member 108 may cover a lower part of one side of the frame of the solar panel 104. Alternatively, the array-roof integration member 108 may cover an entire side of the frame of the solar panel 104.
As further shown, the array-roof integration member 108 is advantageously attached to a side of the solar panel 104 and to the roof 102. Various mechanisms may be used to attach the array-roof integration member 108, including, for example, screws, nails, or other attaching mechanisms.
FIG. 3 is a front cross-sectional view of a solar panel 104 on a roof 102 with an array-roof integration member 108 in accordance with an embodiment of the invention. This view is parallel to the plane of the roof and shows how the array-roof integration member 108 covers from view the space between the solar panel 104 and the roof 102.
As shown, one embodiment of the array-roof integration member 108 includes air gaps (or vents or slits) 302 to facilitate airflow underneath the solar panel 104. The air gaps 302 may be vertical as shown. In other implementations, the air gaps 302 may be otherwise configured, such as horizontally or in other forms.
In accordance with one embodiment, the air gaps 302 of the array-roof integration member 108 is configured on the bottom of the array with a net free vent area (NFVA) to provide the equivalent venting as at least a two inch stand-off height for rack mount systems if the sides do not allow airflow (so that the airflow is only in the top-to-bottom direction). Here, NFVA refers to the unblocked area in percentage. If the sides are open (so that airflow is also in the side-to-side direction), then of the array-roof integration member 108 may be configured with a smaller NFVA.
For example, given an installation where the sides do not allow for airflow, if the installed stand-off height is to be four inches and the array-roof integration member is nearly perpendicular to the plan of the array, then the air gaps 302 would be configured with at least fifty percent (50%) unblocked area or NFVA (2 inches divided by four inches). In a preferable embodiment, the array-roof integration member has slope relative to the array, thus providing a greater length of the member compared to the height of the array. Thus, for example, a roof-integration member of approximately 6″ in length on an array with a 4″ stand-off height could be configured with approximately 25-40% unblocked area to provide nearly equivalent airflow.
In one embodiment, the array-roof integration member 108 may be fabricated so as to include the same roof shingles on its surface as the roof 102. This advantageously provides for visual integration. The roof shingles may be attached to an underlying support piece of the array-roof integration member 108.
Alternatively, the array-roof integration member 108 may be fabricated to have a surface color and/or pattern and/or texture that matches or nearly matches the roof shingles. The array-roof integration members 108 may be fabricated with a set of colors and/or patterns to match a variety of roof shingles. In one implementation, the surface color and/or pattern may be formed on an array-roof integration member 108 made of molded plastic.
In an exemplary embodiment, the array-roof integration member 108 is designed to be compatible with and installed upon a roof with relatively thin shingles, such as, for example, composite or asphalt shingles. The relatively thin shingles may be, for example, less than half an inch in thickness.
FIG. 4 is a top planar view of an array 400 of solar panels 104 on a roof 102 with an array-roof integration member 108 in accordance with an embodiment of the invention. As shown, the array 400 may not necessarily be rectangular, although it could be rectangular in a typical installation. Supports between the solar panels 104 and the roof 102 are not shown in this view. As shown, the array-roof integration member 108 may be affixed to one side of the array 400 of solar panels 104. In an exemplary embodiment, the array-roof integration member 108 may be affixed to the side of the array 400 which faces the bottom (lower) portion of the roof 102 so as to cover the gap between the solar panels 104 and the roof 102 from view by persons standing on the ground and viewing the roof 102. The array-roof integration member may include a means to remove debris that may collect underneath the member and/or the PV modules. For example, a hinge or detachment 402 may be located at the top of the integration member to allow pivot motion or detachment of at least a portion of the integration member.
FIG. 5 is a top planar view of an array 500 of solar panels 104 on a roof 102 with a plurality of array-roof integration members 108 in accordance with an embodiment of the invention. As shown, the array 500 may not necessarily be rectangular, although it could be rectangular in a typical installation. Supports between the solar panels 104 and the roof 102 are not shown in this view. As shown, the array-roof integration members 108 may be affixed to two or more sides of the array 500 of solar panels 104. In the embodiment shown, the array-roof integration members 108 may be affixed to three sides of the array 500, all sides except for the side facing the top (upper) portion of the roof. In this case, the array-roof integration members 108 more completely cover the gap between the solar panels 104 and the roof 102 from view by persons standing on the ground and viewing the roof 102.
FIG. 6A is a front cross-sectional view of a solar panel or panels 104 on an uneven roof structure 602 with a conventional rigid member 604. As shown, the conventional rigid member 604 may be attached to the frame of the solar panel(s) 104 and typically has horizontally-configured vents. In this example, the roof structure is shown to be uneven or bent (not straight). For purposes of illustration, the amount of uneven-ness shown in FIG. 6A is exaggerated compared with a typical uneven roof situation. Due to the uneven roof structure 602, there is a gap formed between the rigid member 604 and the roof 602. This gap 604 is undesirable and is generally aesthetically displeasing to people looking up at the roof. Furthermore, the conventional rigid member 604 is not selected to be either matched to the roof color or complementary to the roof color.
FIG. 6B is a front cross-sectional view of a solar panel or panels on an uneven roof structure with an array-roof integration member 108 in accordance with an embodiment of the invention. In this case, an array-roof integration member 108 is manufactured to be flexible such that it may be configured between the solar panel(s) 104 and the uneven roof structure 602. As shown, the array-roof integration member 108 may be installed to advantageously cover the entire gap between the solar panel(s) 104 and the uneven roof structure 602 such that there is no gap between the integration member 108 and the uneven roof 602. In addition, the array-roof integration member 108 may have a surface color which is selected from a set of surface colors so as to either match the roof color or be complementary to the roof color.
FIG. 6B further shows the air gaps (or vents or slits) 302 in the array-roof integration member 108 which differs from the horizontal vents of the conventional member 604. These air gaps 602 may be vertical as shown, but may also be otherwise configured, such as horizontally, in other implementations.
FIG. 7 is a top planar view of a solar panel (photovoltaic module) 700 in accordance with an embodiment of the invention. The solar panel 700 includes an array of solar cells 702. In addition, areas 704 are present between and around the solar cells 702. In these areas 704, a backsheet of the solar panel 700 is typically visible.
In one embodiment of the present invention, the solar panels 700 are fabricated with a clear (transparent or translucent) backsheet without color. When such a solar panel 700 with a clear backsheet is installed on the roof, the color of the roof surface shows through backsheet-visible areas 704. This advantageously provides an array of areas on the solar panel which match the roof surface in color. In other words, it provides an automatic color tie-in between the solar panel array and the surrounding roof area.
Moreover, the solar panel 700 with the clear backsheet may be further fabricated with bifacial solar cells. Such a configuration advantageously provides further collection of solar energy from light passing through the clear backsheet-visible areas 704 to the backside of the solar cells 702.
In an alternate embodiment, the solar panels 700 are fabricated with a backsheet having a color to match or complement the color of the roof surface. Furthermore, the array-roof integration member(s) 108 may also be fabricated to have a color to match or complement the color of the roof surface. In one specific implementation, grey colored backsheets and panel-integration member(s) may be used for roofs in a “cool” color family, and brown colored backsheets and panel-integration member(s) may be used for roofs in a “warm” color family.
While specific embodiments of the present invention have been provided, it is to be understood that these embodiments are for illustration purposes and not limiting. Many additional embodiments will be apparent to persons of ordinary skill in the art reading this disclosure.

Claims

1. A photovoltaic apparatus comprising:

a support structure attached to a roof;

a plurality of photovoltaic modules arranged in an array and attached to the support structure so as to form a gap between the roof and the array; and

a first array-roof integration member attached to a first side of the array, wherein the array-roof integration member covers the gap so that the array appears integrated with the roof.

2. The apparatus of claim 1, wherein the array-roof integration member is a flexible member.

3. The apparatus of claim 1, wherein the array-roof integration member has a surface color or color pattern and surface texture which is selected from amongst a set of surface colors or color patterns and surface textures to visually match a color or color pattern and texture of the roof.

4. The apparatus of claim 1, wherein the array-roof integration member has a surface color which is selected from amongst a set of surface colors to be visually complementary to a color of the roof.

5. The apparatus of claim 1, wherein the roof is sloped, and wherein the first side of the array is located on a lower portion of the sloped roof, further comprising:

a second array-roof integration member attached to a second side of the array, wherein the array-roof integration member covers a gap between the second side of the array and the roof; and

a third array-roof integration member attached to a third side of the array, wherein the array-roof integration member covers a gap between the third side of the array and the roof.

6. The apparatus of claim 1, wherein the array-roof integration member is covered with shingles which are less than half an inch in thickness.

7. The apparatus of claim 6, wherein the array-roof integration member comprises a plurality of shingles attached to a support piece.

8. The apparatus of claim 1, wherein the array-roof integration member comprises molded plastic having a colored surface.

9. The apparatus of claim 1, wherein the array-roof integration member comprises formed metal having a colored surface.

10. The apparatus of claim 1, wherein a rigid frame surrounds each photovoltaic module.

11. The apparatus of claim 1, further comprising:

a plurality of air gaps in the first array-roof integration member, wherein the air gaps are configured to provide a predetermined minimum net free vent area.

12. The apparatus of claim 1, further comprising:

a clear backsheet in each photovoltaic module; and

areas on each photovoltaic module through which the backsheet of the module is visible.

13. The apparatus of claim 12, wherein the photovoltaic modules comprise bifacial modules which collect solar energy from both faces of each module.

14. The apparatus of claim 1, further comprising:

a module with a colored back sheet chosen to complement or match the roof color.

15. The apparatus of claim 1, further comprising:

a mechanism to remove debris.

16. A method of installing a photovoltaic apparatus upon a sloped roof, the method comprising:

attaching a support structure to a roof;

attaching a plurality of photovoltaic modules to the support structure so as to form a photovoltaic array, each of the photovoltaic modules comprising a plurality of photovoltaic cells; and

attaching a first array-roof integration member to a first side of the photovoltaic array, wherein the array-roof integration member covers a gap between the first side of the photovoltaic array and the roof so that the array appears integrated with the roof.

17. The method of claim 16, wherein the array-roof integration member is a flexible member.

18. The method of claim 16, wherein the array-roof integration member has a surface color or color pattern and surface texture which is selected from amongst a set of surface colors or color patterns and surface textures to visually match a color or color pattern and surface texture of the roof.

19. The method of claim 16, wherein the array-roof integration member has a surface color which is selected from amongst a set of surface colors to be visually complementary to a color of the roof.

20. The method of claim 16, wherein the first side of the array is located on a lower portion of the roof, further comprising:

attaching a second array-roof integration member to a second side of the array, wherein the array-roof integration member covers a gap between the second side of the array and the roof; and

attaching a third array-roof integration member to a third side of the array, wherein the array-roof integration member covers a gap between the third side of the array and the roof.

21. The method of claim 16, wherein the roof is covered with shingles which are less than half an inch in thickness.

22. A photovoltaic apparatus comprising:

a support structure attached to a sloped roof, wherein the roof is covered with shingles which are less than half an inch in thickness;

a plurality of photovoltaic modules arranged in an array and attached to the support structure, each of the photovoltaic modules comprising a plurality of photovoltaic cells; and

an array-roof integration member attached to a side of the array, wherein the side of the array is located on a lower portion of the sloped roof, wherein the array-roof integration member covers a gap between the side of the array and the roof, and wherein the array-roof integration member is selected from a predetermined set of said members so as to have a visible surface which is visually compatible with the shingles.

23. A kit for mounting a photovoltaic apparatus on a roof comprising:

a support structure configured for attachment to a roof;

a plurality of photovoltaic modules configured to be attached to the support structure so as to form a gap between the roof and the array; and

an array-roof integration member configured to be attached to a first side of the array such that the array-roof integration member covers the gap so that the array appears integrated with the roof.