GB2543345A

GB2543345A - Apparatus for securing a photovoltaic module to a batten on a roof

Info

Publication number: GB2543345A
Application number: GB1518314.8A
Authority: GB
Inventors: Brand Ryan; Rose Eastwell Hannah; Eltringham Steven; Italiano Peter; Charles Sturgeon Jonathan
Original assignee: Solar Century Holdings Ltd
Current assignee: Solar Century Holdings Ltd
Priority date: 2015-10-16
Filing date: 2015-10-16
Publication date: 2017-04-19
Also published as: GB201518314D0

Abstract

An apparatus for securing a photovoltaic module 206 to a roof batten 105 with a module frame having no predrilled fastening holes, where the apparatus is C-shaped in cross section with an upper flange which fits between the frame and the batten 105, a lower flange under the batten and a web abutting the side of the batten. The lower flange may have, in the direction away from the web, a first portion angled towards the upper flange, and a second portion 404 angled away from the upper flange. A self-tapping fastening element 901 may be screwed through the frame of the solar panel, through said apparatus and into the batten. The apparatus may be formed from a metal or alloy, with an elastic modulus enabling bending, and may be formed via an aluminium extrusion process. The gap between flanges may be 25mm and fit a BS5534 compliant batten.

Description

Apparatus for Securing a Photovoltaic Module to a Batten of a Roof

CROSS REFERENCE TO RELATED APPLICATIONS

This application represents the first application for a patent directed towards the invention and the subject matter.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus for securing a photovoltaic module to a batten of a roof, and a method of using said apparatus.

Photovoltaic modules (also known as solar panels) are increasingly being installed as part of a roof as opposed to as a superstructure over a roof, as part of a trend referred to as building-integrated photovoltaics. In residential settings, this involves completely replacing existing roofing elements such as tiles or slates with photovoltaic modules, which tend to form an interlocking, modular system. Examples of such systems are available from the present applicant, such as the C21e (RTM) range.

Newer designs such as SunStation (RTM), also available from the present applicant, address issues such as catering for different batten spacings in the multitude of different roofs so as to reduce production and installation complexity. A problem encountered with attempts to provide such a universal system is that there are compromises in terms of the fastening elements that must be used. In addition, because the photovoltaic modules are much larger than a normal roofing element, the load they create is spread over fewer points. This may result in the photovoltaic modules not being secured to the battens of the roof to the requisite degree to pass more stringent wind uplift rests.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided an apparatus for securing a photovoltaic module to a batten of a roof, said photovoltaic module being of the type having a frame with no pre-drilled holes for fastening elements, having the features set out in claim 1.

According to another aspect of the present invention, there is provided a method of installing a photovoltaic module on a roof having battens, the photovoltaic module being of the type having a frame with no pre-drilled holes for fastening elements, comprising the steps set out in claim 8.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Figure 1 shows a residential building 101 where the present invention can be deployed as part of the installation of an array of photovoltaic modules;

Figure 2 shows a photovoltaic module 112; and

Figure 3 shows a cross-section of a prior art installation of the photovoltaic modules 109 and 112;

Figure 4 shows an apparatus 401 for securing a photovoltaic module to a batten of a roof according to the present invention;

Figures 5A and 5B show, respectively, the apparatus 401 and a variant thereof in cross section;

Figure 6 shows the insertion of the apparatus 401 onto a batten 105;

Figure 7 shows the apparatus 401 in place on the batten 105;

Figure 8 shows the photovoltaic module 112 placed on the apparatus 401;

Figure 9 shows the photovoltaic module 112 being secured to the apparatus 401 using a fastening element; and

Figure 10 shows a cross-sectional view of the photovoltaic module 112 after being secured to the batten 105 of the roof 102 using the apparatus 401.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 A residential building 101 is illustrated in Figure 1, having a roof 102. In the present example, the building 101 is a house having a tiled roof, and so it comprises a plurality of tiles arranged and mounted using conventional techniques. It should be noted that, although the roofing elements, such as element 103, are tiles in the present example, in alternative roofs embodying the present invention, the roof is formed of other types of roofing elements such as fibre cement slates, artificial or reconstituted slates, plain natural slates, interlocking tiles, etc.

As illustrated in the Figure, the roof 102 is in the process of being retiled, and thus its rafters 104 and battens 105 mounted thereon are exposed. In the present example, the building 101 is located in the United Kingdom, and so the battens 105 are BS5534 standards-compliant and so have a cross section of 50 millimetres in width and 25 millimetres in depth. It will be appreciated that the principles of the invention disclosed herein are not particular to the exact size of batten, and so other standard batten sizes may be accommodated.

An engineer is in the process of installing an array 106 of interlocking photovoltaic modules onto the roof to enable power generation for the building 101 using solar energy. Each one of the photovoltaic modules 107, 108, 109, 110, 111 and 112 in the array is identical, and so each module matches the other ones; the description herein of photovoltaic module 112 is thus applicable for all in the array.

Figure 2

The photovoltaic module 112 is illustrated in isolation in Figure 2.

The photovoltaic module 112 comprises a photovoltaic laminate 201 surrounded by a frame 202. The frame comprises a rear edge 203, a front edge 204, a right edge 205 and a left edge 206. The front edge 204 is designed to overlap the rear edge of a matching photovoltaic module -referring to Figure 1, this would be photovoltaic module 111.

Referring again to Figure 2, the right edge 205 is designed to interlock with the left edge of a matching photovoltaic module - referring to Figure 1, this would be photovoltaic module 109.

Ease of manufacture and installation of the photovoltaic module illustrated in Figure 2 is increased by it having no pre-drilled holes for fastening elements. Thus, the same photovoltaic modules may be installed on a wide variety of roofs irrespective of batten spacing. Thus, instead of pre-drilled holes for fastening elements, the left edge 206 only includes a scribed channel 207 therealong. During installation, self-tapping sheet metal screws are inserted at each intersection of the scribed channel 207 and the battens 105 of the roof 102. In this way, the battens 105 of the roof effectively form part of the chassis of the array 106

Figure 3 A cross sectional view of the interlock between photovoltaic module 112 and 109 in the direction from the ridge to the eaves of the roof when installation has been completed in accordance with methods and apparatus of the prior art is shown in Figure 3.

As shown in the Figure, the right edge 205 of the photovoltaic module 112 interlocks with the left edge 301 of the photovoltaic module 109. The left edge 301 is secured to one of the battens 105 by, as described previously, a self-tapping sheet metal screw 302.

As will be immediately apparent, the self-tapping sheet metal screw 302 whilst being specified to assist ease of installation, is not optimal for engagement with a wooden batten due to the incorrect thread type. There is also a limit on the length of screw that can be specified, as the depth of the battens 105 is fixed at 25 millimetres in the present example. The screw cannot exit the underside of the batten, as there is a risk that the tip could pierce the felt or sarking of the roof, compromising its weather tightness.

Due to this use of self-tapping sheet metal screws, it has been found that the required resistance to wind uplift is not met in some circumstances. Even the addition of two screws per batten has been found in testing not to secure the array 106 to the required degree. However, ease of installation is still paramount, especially to aid in increasing the uptake of solar power and reduce costs.

Figure 4

An apparatus 401 for securing a photovoltaic module to a batten of a roof, where the photovoltaic module has a frame with no pre-drilled holes for fastening elements, is shown in isometric view in Figure 4.

The apparatus 401 generally takes the form of a substantially square-cornered C-shape extrusion. It therefore comprises an upper flange 402, a web 403 and a lower flange 404.

As will be described further with reference to Figures 6 to 10, the apparatus 401 is intended to be placed over the batten in a roof to which a photovoltaic module is to be secured. The apparatus in practice will be placed between the batten and the frame, with a fastener such as a selftapping screw screwed through the frame and into the apparatus 401.

Figures 5A & 5B

The apparatus 401 is shown in cross-section in Figure 5A.

In order to assist the fitting of the apparatus 401 over a roofing batten, the lower flange 404 includes, in the direction away from the web 403, a first portion 501 which is angled towards the upper flange 402, and a second portion 502 which is angled away from the upper flange 402.

This allows the opening between the upper flange 402 and the lower flange 404 to be larger than the batten to assist in locating it thereon.

In a specific embodiment, the apparatus 401 is made from a metal or alloy that allows sufficient deformation so that the upper flange 402 and lower flange 404 can bend apart so that the first portion 501 of the lower flange will lie parallel to the upper flange 402. This can be done by selecting a material with an elastic modulus to allow this small degree of deformation, to assist installation, but still provide the strength required to effectively clamp the photovoltaic module to the batten.

Thus, in the present example, the apparatus 401 is aluminium, and in a specific embodiment is an extrudate of aluminium formed by extrusion of the known type. As described previously, however, in other embodiments, the apparatus could be made of steel or another metal or alloy and made by other processes. A variant of the apparatus 401 is shown in Figure 5B, in which serrations 511 are incorporated on the inner surface of the lower flange 404 to grip the batten following installation.

Figure 6

The beginning of process of installation of the apparatus 401 to assist in securing photovoltaic module 112 to roof 102 is shown in Figure 6.

After obtaining the apparatus 401, it is lined up with a batten 105 at a suitable position so that the frame 202 of the photovoltaic module 112 will line up with it. This may be achieved by marking the batten appropriately, as shown in the drawing by marks 601 and 602.

The apparatus 401 is inserted over the batten 105 in the direction 603 from the ridge to the eaves of the roof 102.

Alternatively, the photovoltaic module 112 may be placed on the batten 105 first, with the apparatus 401 being slid into position under the frame 202.

Figure 7

The apparatus 401 is shown inserted on the batten 105 in Figure 7.

Installation of the apparatus 401 is such that the upper flange 402 lies above the batten 105, the web 403 abuts the ridge-side edge of the batten 105, and the lower flange 404 fits under the batten 105.

It will be appreciated that an example of apparatus 401 will be used on each batten 105 covered by the photovoltaic module 112 going down the roof 102.

Figure 8

The photovoltaic module 112 is shown installed on the apparatus 401 in Figure 8. The photovoltaic module 112 is placed on the roof 102 such that the left edge 206 lies over the apparatus 401.

Figure 9

The photovoltaic module 112 is shown being secured to the apparatus 401 in Figure 9. In this example, a shorter self-tapping sheet metal screw 901 is inserted in the scribe mark 207 on the left edge 206 of the frame 202 of the photovoltaic module 112. It is then screwed through the left edge 206, into the apparatus 401 and into the batten 105.

Figure 10

The combination of the photovoltaic module 112 and the apparatus 401 following installation is shown in cross section in the direction along the ridge of the roof in Figure 10.

It will be seen that the apparatus 401 now provides the main means for securing the photovoltaic module 112 to the batten 105. Whilst the screw 901 still penetrates the batten 105, and this may assist in terms of preventing lateral movement, it is no longer solely relied on for withdrawal resistance during wind uplift events.

Thus, the apparatus 401 moves the primary concentration point of force away from the interface between the thread of screw 901 and the batten, to the interface of the lower flange 404 and the batten. In this way, considering the roof 102 and array 106 as a whole, updrafts pull against the underside of the battens on the roof, rather than on the threads of the selftapping screws such as screw 901 in the battens.

In addition, it will be recognised that the join between the photovoltaic modules and the various apparatuses 401 on the roof is supplied by sheet metal screws, and thus the threads thereof are optimal for the application, unlike in the prior art installation in which they interface with the wooden battens. In this way, installation of the array 106 is kept simple, but the requirements in terms of uplift resistance may be met.

Further distribution of load may be provided by extending the length of the upper flange 402 and the lower flange 404 of the apparatus 401. Such an alternative configuration will assist in a reduction of the bending of the battens 105 during updraft events.

In alternative roofing environments in which sandwich panels are used rather than more traditional rafter-based construction, it is possible to provide additional strength by provision of a fastening element of a length sufficient to not only pierce the upper flange 402, but to also pass all the way through the rafter 105 and through the lower flange 404. This is because there is no felt or sarking which may be compromised by the exiting of the tip of the fastening element in such a construction. In this way, the apparatus 401 will be tightened around the batten 105 by the pulling together of the upper and lower flanges by the fastening element.

Claims

CLAIMS The invention claimed is:

1. An apparatus for securing a photovoltaic module to a batten of a roof, said photovoltaic module being of the type having a frame with no pre-drilled holes for fastening elements, wherein: the apparatus has a substantially square-cornered C-shape cross section comprising an upper flange to fit between said frame and said batten, a web to abut a ridge-side edge of said batten, and a lower flange to fit under said batten.

2. The apparatus of claim 1, in which the lower flange comprises, in the direction away from the web, a first portion angled towards the upper flange, and a second portion angled away from the upper flange.

3. The apparatus of claim 2, in which the apparatus is made from a metal or an alloy having an elastic modulus to allow the rear flange to bend such that the first portion may lie parallel to the upper flange under deformation.

4. The apparatus of any one of claims 1 to 3, in which the lower flange comprises one or more serrations on its inner surface to grip the roofing batten.

5. The apparatus of any one of claims 1 to 4, in which the apparatus is formed by a process of extrusion.

6. The apparatus of claim 5, in which the apparatus is an extrudate of aluminium.

7. The apparatus of any one of claims 1 to 6, in which a gap between the upper flange and the lower flange is 25 millimetres to fit a BS5534 standard-compliant batten.

8. A roof having a batten to which a photovoltaic module has been secured using an apparatus according to any one of claims 1 to 7 in combination with a fastening element.

9. A method of installing a photovoltaic module on a roof having battens, the photovoltaic module being of the type having a frame with no pre-drilled holes for fastening elements, comprising the steps of: obtaining an apparatus according to any one of claims 1 to 7; positioning said apparatus over a batten of the roof; placing the frame on the roof, such that it lies over said apparatus; screwing a self-tapping fastening element through the frame, through said apparatus and into the batten.

10. Apparatus substantially as herein described with reference to and as shown in the accompanying drawings.