GB2576691A

GB2576691A - Solar roof tiles

Info

Publication number: GB2576691A
Application number: GB1808365.9A
Authority: GB
Inventors: Mason Andrew
Original assignee: Champion Mouldings Ltd
Current assignee: Champion Mouldings Ltd
Priority date: 2018-05-22
Filing date: 2018-05-22
Publication date: 2020-03-04
Anticipated expiration: 2038-05-22
Also published as: GB2576691B; GB201808365D0

Abstract

A roof tile 10 comprises a plastics main body portion 12 and an integrally-formed solar PV panel , wherein the solar PV panel is over-moulded into the main body 12 with a layer 22 of plastics overlying a front surface of the PV panel . The thickness of the layer overlying the PV panel is sufficiently thin and transparent to as to permit solar radiation to penetrate therethrough to the front surface of the PV panel. The cover layer may be <0.5mm thick. The cover lay may be transparent to UV light and may have a UV-transmittance of >50% at light wavelengths of <300nm. Internal wiring is suitably provided, with weatherproof connectors for connecting the roof tile 10 to a wiring loom 20. The tile may have fixing holes or slots 34.

Description

SOLAR ROOFTILES

This invention relates to solar roof tiles.

It has been proposed, in recent years, to install solar panels, that is to say photovoltaic cells, on the roofs of buildings for the purposes of locally-generating electrical power from sunlight. Known photovoltaic (PV) arrays tend to be fitted on top of the existing roof structure because it is widely accepted that the PV panels themselves need to be directly exposed to sunlight for maximum efficiency. However, as the PV cells themselves tend to have a silver-bluish hue, PV arrays can be unsightly and/or appear quite different from the underlying roof structure (which is typically tiled).

There also exists, in certain areas, a problem associated with obtaining planning permission for the installation of PV arrays, especially in listed building or conservation areas. The reason for this is that the installation of a PV array can be deemed to detract from the overall aesthetics of the building/area, which can lead to outright PV installation prohibition, or permission to install, but with restrictions imposed.

A need therefore exists for an improved type of solar PV array, which can be fitted unobtrusively onto existing tiled roofs.

According to the invention, there is provided a roof tile comprising a plastics main body portion and an integrally-formed solar PV panel, wherein the solar PV panel is over-moulded into the main body with a layer of plastics overlying a front surface of the PV panel.

Unlike known roof tile-like PV systems, where the PV panel is exposed at the surface, the PV panel of the present invention is located slightly below the surface and is covered by a layer of plastics. Accepted wisdom in the art indicates not covering the PV panel in any way so as to optimise the amount of light that can be absorbed by it. This necessarily results in the PV panel being outwardly visible and thus potentially giving rise to an undesirable aesthetic.

By contrast, however, the PV panel of the present roof tile is over-moulded within the main body and is thus, at least partially, obscured from view. This runs against the accepted wisdom in the art (of leaving the PV panel's front surface exposed) and the skilled person will readily appreciate that there would naturally be a decrease in efficiency of the solar PV panel by doing this.

However, the present invention proposes to over-mould a solar PV panel with a very thin layer of plastics, which, due to its material of manufacture, and/or the thickness of the said layer, is either substantially transparent to UV radiation, or is only minimally absorptive of UV radiation.

By selecting the appropriate material, colour and for thickness of plastic from which the main body is manufactured, it is possible to visually obscure the solar PV panel from view (thereby avoiding the intrusive, and/or unsightly shiny and/or silver-blue hue), but at the same time, to allow sufficient UV light to penetrate the layer to reach the solar PV panel underneath.

Suitably, the layer of plastics overlying the front surface of the PV panel is less than 2mm thick, preferably less than 1mm thick, and most preferably, less than 0.5mm thick. This can be accomplished, in practice, by employing a process akin to IML (in-mould labelling) so as to obtain a thin flash layer overlying the PV panel. Clearly (due to mass - thickness absorption considerations) the thinner the layer of plastics overlying the front surface of the PV panel, the greater the efficiency of the PV panel will be, in use.

Suitably, the material from which the main body is made, or at least the layer overlying the front surface of the PV panel is UV-transmissive, by which it is meant, having a transmittance of >50% at light wavelengths of <300nm. Clearly, the higher the transmittance of the material at visible/UV wavelengths, the greater the efficiency of the PV panel will be, in use.

Other advantages of this configuration (i.e. having a layer of plastics overlying the front surface of the PV panel) include enabling the outer surface of the main body to be manufactured so as to resemble a conventional roof tile, that is to say having an undulated/stippled/uneven surface. This may further obscure the PV panel from view, which may add to the benefits of the invention.

Moreover, because the PV panel of the invention is over-moulded into the main body of the rooftile, it is protected, to a certain extent, from the elements. This may lengthen the life/duty cycle of the PV panel, and may facilitate cleaning the roof tiles post-installation. For example, the invention permits the use of a pressure washer, without risking damaging the PV panel, which is located underneath the (protective) layer of plastics overlying the front surface of the PV panel.

Suitably, electrical connections are integrally formed into (the rear) of the roof tile to enable the roof tile to be electrically connected to a power circuit. In a preferred embodiment of the invention, cables connecting the contacts of the solar PV panel are embedded within the main body and emerge from the main body via a releasable electrical connection. Suitably, the releasable electrical connection is waterproof/water resistant, (e.g. IP-rated), so as to withstand the elements. Such a configuration enables a wiring loom to be fitted to a roof prior to tiling with roof tiles according to the invention, thereby enabling the roof tiles to be plugged into the wiring loom as they are installed one by one. This also has the advantage of enabling faulty tiles to be subsequently removed and replaced individually, without having to re-wire the entire array.

Preferably, roof tiles comprise fixing means to enable them to be secured to a roof. This typically comprises an upper flanged portion of each roof tile, which has mounting formations, such as through holes, which enable the tile to be nailed, screwed, or otherwise affixed to an underlying roof structure.

Preferred embodiments of the invention shall now be described, by way of example only, with a reference to the accompanying drawings in which:

Figure 1 is a schematic cross-sectional view of a roof tile in accordance with the invention;

Figure 2 is a front perspective view of a roof tile in accordance with the invention; and

Figure 3 is a schematic, perspective view of a roof tile system partially installed on a roof.

Referring to Figure 1 of the drawings, a roof tile 10 comprises a main body 12, which is manufactured from, for example, injection-moulded plastics. Over-moulded within, that is to say embedded within, the main body 12 is a solar PV panel 14. A cable 16 connects the solar PV panel 14 to a waterproof connector 18, for onward connection to a wiring loom 20.

It can be seen, from Figure 1 of the drawings that the main body 12 comprises a thin layer 22 of plastics material, the thickness 26 of which is ideally less than 1mm. The thin layer 22 overlies a front face 24 of the solar PV panel 14.

For the reasons previously stated, the thickness 26 of the thin layer 22 is sufficiently small to enable UV radiation 28 to penetrate the thin layer 22 and interact with the front surface 24 of the solar PV panel 14, thereby generating an electrical current, which is outputted via the connector 18 and cable 16 to the wiring loom 20.

Referring to Figure 2, a roof tile 10 in accordance with the invention has a main body 12 comprising an upper part 30 and a lower part 40. The upper part 30 has a tab portion 32, which comprises slotted apertures 34 through which mounting screws (not shown) can be inserted. The upper part 30 also has a further set of slotted apertures 36 located in recesses 38. The former slotted apertures 34 are aligned substantially vertically, and this permits vertical adjustment 40 of the roof tile 10; whereas the latter slotted apertures 36 are aligned horizontally, and this permits lateral adjustment 42 of the roof tile 10, during installation.

To secure the rooftiles 10 to an underlying structure, a screwor other fastener can be inserted through the latter slotted apertures 36 and then through a vertical slotted aperture 34 of an underlying roof tile. This gives rise to the staggered/overlapping arrangement depicted in Figure 3 of the drawings.

To facilitate alignment and the correct spacing of the roof tiles 10, various markers/indicia are provided on upper part 30 of the roof tile 10, as can be seen in Figures 2 and 3 of the drawings.

The upper part 30 of the roof tile 10 has cut away sections 46 and these enable connections of the wiring loom (not shown) to be fed up between underlying tiles to connect to the connectors 18 of uppermost tiles.

The lower part 40 of the roof tile 10 has a textured outer surface 22 which, in the illustrated embodiment, is textured so as to resemble a slate. To properly mimic the appearance of slate tiles, the edges 48 of the lower part 40 are uneven and rounded-off, as can be seen, in particular in Figures 2 and 3 of the drawings.

The lower part 40 of the rooftile 10 has embedded within it, a solar PV panel 14, whose outline is indicated in Figures 2 and 3 of the drawings. It will be seen that the majority of the solar PV panel

14 is exposed - even when overlying tiles 10 are placed on top thereof. It will be apparent that due to the orientation of the slotted apertures 34, that the amount of overlap between the lower edge 52 of an upper tile and the upper periphery 56 of the solar PV panel 14 can be user-adjusted. Ideally, there would be no overlap - so as to present the maximum possible surface area of the solar PV panel to instant light but it would also be appreciated, that in certain situations, a certain amount of overlap may be required, for example where the roof battens so dictate.

The thickness 26 of the material 22 overlying the solar PV panel 14 is very thin so as to reduce, as far as possible, the absorption of light instant on the solar PV panel 14 underneath.

It will be appreciated that the foregoing embodiments are merely exemplary of the invention and that the invention is not restricted to the particular shape/configuration of the roof tiles shown.

For example, the length and width of the roof tiles 10 may be adjusted to resemble other types of roof tile, as could its surface finish 22 and the edge profiles 48 thereof.

Claims

1. A roof tile comprising a plastics main body portion and an integrally-formed solar PV panel, wherein the solar PV panel is over-moulded into the main body with a layer of plastics overlying a front surface of the PV panel.

2. The roof tile of claim 1, wherein the solar PV panel is over-moulded with the layer of plastics, and wherein due to the thin layer's material of manufacture, and/or its thickness, the layer of plastics is substantially transparent to UV radiation, or is only minimally absorptive of UV radiation.

3. The roof tile of claim 1 or claim 2, wherein the thickness of layer of plastics overlying the front surface of the PV panel is less than 2mm.

4. The roof tile of any preceding claim, wherein the thickness of layer of plastics overlying the front surface of the PV panel is less than 1mm.

5. The roof tile of any preceding claim, wherein the thickness of layer of plastics overlying the front surface of the PV panel is less than 0.5mm.

6. The roof tile of claim 5, wherein the tile is formed by an in-mould labelling-like process whereby a thin flash layer is formed, which overlies the PV panel.

7. The roof tile of any preceding claim, wherein the material from which the layer overlying the front surface of the PV panel is made is UV-transmissive.

8. The roof tile of claim 7, wherein the UV-transmissive material has a transmittance of >50% at light wavelengths of <300nm.

9. The roof tile of any preceding claim, further comprising one or more electrical connections integrally formed into the roof tile to enable the roof tile to be electrically connected to a power circuit.

10. The roof tile of claim 9, comprising cables connecting contacts of the solar PV panel, which are embedded within the main body and emerge from the main body via a releasable electrical connection.

11. The roof tile of claim 10, wherein the releasable electrical connection is waterproof/water resistant.

12. The roof tile of any preceding claim, further comprising fixing means adapted, in use, to enable the roof tile to be secured to a roof.

13. The roof tile of claim 12, wherein the fixing means comprises an upper flanged portion of the roof tile, which has through holes.

14. The roof tile of claim 13, wherein the through holes comprise slotted apertures.

15. The roof tile of any preceding claim, wherein an outer surface of the main body comprises a textured surface.