WO2010007103A1

WO2010007103A1 - Roofing panel and roof structure

Info

Publication number: WO2010007103A1
Application number: PCT/EP2009/059082
Authority: WO
Inventors: Laurentius Gerardus Johannes Wolters
Original assignee: We Engineering Bv
Current assignee: We Engineering Bv
Priority date: 2008-07-18
Filing date: 2009-07-15
Publication date: 2010-01-21
Anticipated expiration: 2011-01-18
Also published as: NL1035720C2

Abstract

The invention relates to a roofing panel comprising a subsequently box-like structure having an upper surface, a lower surface of identical shape, which is arranged parallel to and spaced from said upper surface, and a circumferential edge extending along the circumference of said upper surface and said lower surface and therebetween, wherein the upper surface is formed by the upper surface of an absorption solar collector and the cavity of the box-like structure is filled with an insulation material.

Description

ROOFING PANEL AND ROOF STRUCTURE

The invention relates to a roofing panel for use in a roof structure. Such roofing panels are commonly used in the construction of new buildings for guickly providing a frame consisting of rafters and purlins with a covering construction, on which roof tiles, for example, can subseguently be laid. Such roofing panels usually consist of an upper plate and a lower plate of identical shape, which lower plate is arranged parallel to and spaced from the upper plate. The space between said upper plate and said lower plate is filled with an insulation material, such as polyurethane foam or polystyrene foam, for example.

It has furthermore become more and more common to take into account the possibility of alternative energy sources when designing new buildings. Solar collectors are freguently used in that regard. Such solar collectors are mounted on the roof and connecting pipes for the solar collector are passed through the roofing panels to the interior of the building.

The solar collectors may be either absorption collectors or photovoltaic collectors. In the case of photovoltaic solar collectors, use is made of the photovoltaic effect, making it possible to extract electric energy directly from sunlight. In the case of absorption solar collectors, a heat-exchanging fluid is heated by means of the sunlight, which fluid can subseguently be utilised for heating rooms or heating tap water, making use of a heat exchanger installed in the building, or for generating electric energy through conversion, for example by a Stirling engine.

These common constructions, in which a solar collector is mounted on an existing roof, entail high costs and have a long cost recovery period. Because of this, the acceptance level of solar collectors on a roof is limited.

It is an object of the invention to reduce the costs of installing a solar collector on the roof so as to increase the acceptance level of such solar collectors. According to the invention, this objective is accomplished with a roofing panel comprising a subseguently box-like structure having an upper surface, a lower surface of identical shape, which is arranged parallel to and spaced from said upper surface, and a circumferential edge extending along the circumference of said upper surface and said lower surface and therebetween, wherein the upper surface is formed by the upper surface of an absorption solar collector and the cavity of the box-like structure is filled with an insulation material. Since the solar collector forms part of the roofing panel, forming at least the upper surface thereof, the roofing panel with the integrated solar collector can readily be installed on a new building to be constructed. The roofing panels are installed on a frame consisting of rafters and purlins in a usual manner, after which only the connecting of the solar collector needs to take place. Since the solar panel forms the upper surface of the roofing panels, there is no longer a need for additional protection, such as roof tiles, for example. Roof tiles need not be provided, therefore. The advantage of such a roofing panel according to the invention is that it makes it possible to realise a significant cost reduction. In one embodiment of the roofing panel according to the invention, the insulation material is a cured foam, such as polyurethane foam or polystyrene foam, for example . Such foams have the advantage of imparting significant rigidity to the roofing panel whilst keeping the weight relatively low .

In a preferred embodiment of the roofing panel according to the invention, a photovoltaic film is provided on the upper surface of the absorption solar collector. Such a photovoltaic film is very thin, usually it is less than 1 mm thick, so that the heat from the solar radiation can readily pass through the photovoltaic film and reach the absorption solar collector. The sunlight itself is converted into electricity by the photovoltaic film. The sunlight is thus optimally utilised, because the solar collector and the photovoltaic film make it possible to utilise the heat as well as the light.

In another preferred embodiment of the roofing panel according to the invention, the absorption solar collector comprises a flat plate forming the upper surface and a lower plate provided on the bottom side of said flat plate, which lower plate is provided with a relief, such that channels are formed between said flat plate and said lower plate. Preferably, the relieved lower plate comprises a padded relief.

Such a construction is easy to manufacture by spot- welding a relatively thin steel sheet to a relatively thick steel sheet, after which a medium is pressed between the two layers, such that the relatively thin plate is deformed and a relief of channels is obtained. Additional advantages of this construction are that a strong surface is obtained for the roofing panel and that the upper surface is flat, so that providing the photovoltaic film will be easy, and that such a construction of steel sheets provides good heat conduction .

In another embodiment of the roofing panel according to the invention, the inlet and the outlet of the absorption solar collector terminate in the cavity of the box-like structure. Said inlet and outlet are thus hidden from view.

Preferably, connecting pipes extend from the inlet and the outlet of the absorption solar collector through the circumferential edge. In this way, the inlet and the outlet can be connected without difficulty, whilst the lines remain largely hidden from view.

In yet another embodiment of the roofing panel according to the invention, the electrical connection points of the photovoltaic film are provided on the circumferential edge of the roofing panel.

In yet another preferred embodiment of the roofing panel according to the invention, the roofing panel comprises coupling means on at least two opposed circumferential sides for coupling two adjacent roofing panels together and possibly coupling connecting pipes. As a result, the roofing panels can be readily arranged to abut each other, and a roof-covering whole can be guickly obtained. The invention further comprises a roof structure comprising a frame of rafters and purlins and roofing panels according to the invention mounted on said frame, which roofing panels are arranged to abut each other.

In a preferred embodiment of the roof structure according to the invention, said roof structure further comprises fitting panels for covering roof parts not covered by the roofing panels so as to cover the frame in its entirety. Preferably, said fitting panels are provided with connecting pipes lines for the absorption solar collectors and the photovoltaic films of the roofing panels . The use of fitting panels makes it possible to produce roofing panels having fixed dimensions, with standardised connections for the solar collector and the films . In a roof structure according to the invention, said roofing panels are arranged to abut each other, and preferably connected together, with the fitting panels ensuring that the roof is fully covered. In addition to that, the fitting panels ensure that the supply and discharge pipes to and from the roofing panels are largely hidden from view and that the connections can be readily made.

The upper surface of the fitting panels is preferably likewise provided with a photovoltaic film. In this way the available surface area is optimally utilised and there is no colour difference between the roofing panels and the fitting panels.

The above and further aspects of the invention will now be explained in more detail with reference to the appended drawings.

Figure 1 is a cross-sectional view of a part of a first embodiment of a roofing panel according to the invention .

Figure 2 is a cross-sectional view of a part of a second embodiment of a roofing panel according to the invention .

Figure 3 is a top plan view of an embodiment of a roof structure according to the invention.

Figure 4 is a cross-sectional view of the roof structure of figure 3.

Figure 5 shows a stand-alone application of a roofing panel according to the invention. Figure 6 shows in cross-sectional view a special use of a roofing panel according to the invention.

In figure 1 a first embodiment 1 of a roofing panel according to the invention is shown, to which a fitting panel 2 is connected. The roofing panel 1 comprises an absorption solar collector consisting of a thick upper plate 3 and a thin padded lower plate 4. An outlet connection 5 is provided on the lower plate 4. The solar collector 3, 4 forms the upper surface of the roofing panel 1. A wooden lower plate 6 is arranged spaced from the flat plate 3. In a roof structure, said wooden plate 6 forms the ceiling of the roof .

The space between the solar collector 3, 4 and the lower plate 6 is filled with an insulation material 7. A connecting pipe 8, which is connected to the connection 5, further extends through said insulation material 7.

The connecting pipe 8 extends up to the lateral surface of the roofing panel 1, where it is connected, by means of a coupling piece 9, to a supply or discharge pipe 10 in the fitting panel 2. Said fitting panel 2 likewise comprises an upper plate 11 and a wooden lower plate 12, preferably with an insulation material 13 therebetween. Supply pipes 10 and 14 are provided in said fitting panel 2. Furthermore, a channel 23 is provided, through which the connecting wires for the photovoltaic layer may extend, for example. Said photovoltaic layer is not shown in the figure, but it is provided on the flat plate 3 of the absorption solar collector 3, 4.

The circumferential edge of the roofing panel 1 is provided with a protrusion 15, which slips into a groove 16 in the fitting panel 2 or in an adjacent roofing panel 1. In this way a connection between the roofing panel 1 and the fitting panel 2 is provided, so that in any case the upper surface 3 and the upper surface 11 will be aligned. To obtain an adequate seal, a rubber string and/or a putty may be provided in said joint 15, 16.

In figure 2 a second embodiment of a roofing panel 20 is shown. Said roofing panel 20 is quite similar to the roofing panel 1 of figure 1, and consequently like parts are provided with the same numerals.

Unlike the roofing panel 1 of figure 1, the roofing panel 20 does not have a wooden lower plate, but it is comprises a steel lower plate 22. Said steel lower plate 22 is flanged, so that the plate 22 forms part of the circumferential edge, and is provided with connecting means 15, which slip into the groove 16 of the fitting panel 21. Figure 2 clearly shows the manner in which two roofing panels 20 can be connected by means of a fitting panel 21.

Figure 3 shows a top plan view of a roof structure 30 according to the invention. The roof structure 30 consists of a number of roofing panels 1, which are connected in a usual manner. See figure 1, for example, in this regard. Fitting panels 2 are provided between the roofing panels 1 and/or on either side thereof. Pipes 10, 14 are provided in said fitting panels 2, which pipes connect the fluid for the absorption solar collector 3, 4. Via a connecting point 31, the pipes 10, 14 extend to, for example, an installation for storing, using or converting the heat .

Figure 4 shows a cross-sectional view of the roof structure 30 of figure 3. The roof structure 30 comprises a number of purlins 32, which support the roofing panels and the fitting panels 1, 2. Via the point 31, the pipes 10, 14 enter the building, where they can be connected to an installation 33 (not shown in detail) . Said insulation 33 processes the heat obtained from the absorption solar collectors 3, 4. Said heat may be stored, it may be used for heating a space or for heating tap water, or it may be used for generating electricity therefrom.

In addition to that, said installation 33 may, on the contrary, be designed to heat the fluid of the absorption solar collectors 3, 4. When the roofing panels are covered with ice and snow, it may thus be easy to clear the roof of ice by causing hot fluid to flow through the absorption solar collectors.

Figure 5 shows a stand-alone application of a roofing panel 1 according to the invention. Although the roofing panels 1 are in principle intended for use as a roof, said panels 1 may also be used as a freestanding solar collector. The roofing panel 1 is to that end placed on a frame of bars 40, 41, so that the roofing panel 1 will be oriented at a desired angle relative to the incident solar radiation. Since the roofing panel is used only as a solar collector, a thinner insulation layer 42 may be used, if desired. In that case the connections 43, 44 of the solar collector will project from the bottom side of the roofing panel 1. The connections 43, 44 are in turn connected to an installation 45. Figure 6 shows a special use of a roofing panel according to the invention. The roofing panel 1 is placed vertically in this figure and forms part of a cavity wall consisting of an outer skin 50 and an inner skin 51. The roofing panel 1 is provided at the level of the inner skin 51. An insulating pane 52 is provided at the level of the outer skin 50. A space 53 is thus formed between the pane 52 and the roofing panel 1. Incident solar radiation will heat the air in the space 53. Said heat can subsequently be utilised by the solar collector 3 in the roofing panel 1. Ventilation grilles 54, 55 and flaps 56, 57 are provided at the upper side and the lower side, respectively, of the roofing panel 1. Said flaps 56, 57 make it possible to have air circulate through the space 53 and to utilise part of the incident heat directly for heating the building.

Furthermore, ventilation grilles 58, 59 are provided on the outer side, which grilles enable air to circulate. By suitably positioning the flaps 56, 57, fresh air can be made to flow through the space 53, in which said fresh air is heated, and subsequently enter the interior space .

Claims

1. A roofing panel comprising a substantially box- like structure having an upper surface, a lower surface of identical shape, which is arranged parallel to and spaced from said upper surface, and a circumferential edge extending along the circumference of said upper surface and said lower surface and therebetween, wherein the upper surface is formed by the upper surface of an absorption solar collector and the cavity of the box-like structure is filled with an insulation material.

2. A roofing panel according to claim 1, wherein the insulation material is a solidified foam, such as polyurethane foam or polystyrene foam.

3. A roofing panel according to claim 2 or 2, wherein a photovoltaic film is provided on the upper surface of the absorption solar collector.

4. A roofing panel according to any one of the preceding claims, wherein the absorption solar collector comprises a flat plate forming the upper surface and a lower plate provided on the bottom side of said flat plate, which lower plate is provided with a relief, such that channels are formed between said flat plate and said lower plate.

5. A roofing panel according to claim 4, wherein the relieved lower plate comprises a padded relief.

6. A roofing panel according to any one of the preceding claims, wherein the inlet and the outlet of the absorption solar collector terminate in the cavity of the box-like structure.

7. A roofing panel according to claim 6, wherein connecting pipes extend from the inlet and the outlet of the absorption solar collector through the circumferential edge.

8. A roofing panel according to any one of claims 3-7, wherein the electrical connection points of the photovoltaic film are provided on the circumferential edge of the roofing panel.

9. A roofing panel according to any one of the preceding claims, wherein at least two opposed circumferential sides comprise coupling means for coupling two adjacent roofing panels together and possibly coupling connecting pipes.

10. A roof structure comprising a frame of rafters and purlins and roofing panels according to any one of the preceding claims mounted on said frame, which roofing panels are arranged to abut each other.

11. A roof structure according to claim 10, comprising fitting panels for covering roof parts not covered by the roofing panels so as to cover the frame in its entirety.

12. A roof structure according to claim 11, wherein the fitting panels are provided with connecting lines for the absorption solar collectors and the photovoltaic films of the roofing panels.