ROOF PANEL WITH AN INTEGRATED SOLAR PANEL AND ROOF COMPRISING SUCH PANELS

DESCRIPTION The present invention, according to a first aspect thereof, relates to a roof panel with an integrated BIPV-type solar panel, comprising a casing with a bottom plate and upright side walls and a solar panel which extends above said bottom plate, spaced therefrom by some distance, and which substantially closes said casing, wherein at least one opening is present in the roof panel between the solar panel and the casing at the bottom side remote from the ridge of the roof when the roof panel is used on a roof. The abbreviation BIPV stands for "Building Integrated Photovoltaic", which means that the panel is or is to be mounted on a roof instead of roof tiles. This in contrast to solar panels designed for placement on the roof tiles of a roof. A known BIPV-type roof panel comprises a casing with three upright circumferential walls, viz. an upper wall and two side walls. Unless stated otherwise, it is the orientation intended for use on a sloping roof that is meant when the orientation of a roof panel is mentioned herein. The casing is designed to be fixed to the roof boarding. At the bottom side, the bottom plate ends without an upright wall. At the upper side, the three upright walls each blend into edges extending away from the panel, and in use roof tiles are supported on the upper edge and on one side edge, whilst the other side edge itself is supported on roof tiles. In some cases roof tiles are supported on the upper edge and both side edges. The roof panel is thus incorporated in the roof as if the roof panel were one large roof tile. A solar panel extends between the two side edges, to which it is also attached. At the upper side, the solar panel is spaced from the upper wall of the casing, to be true, but upon placement of the solar panel the gap thus present is covered by a roof tile or a roof panel disposed there above, which is supported on the roof panel in question and which overlaps the roof panel in question up to a position beyond said gap. This makes it possible to provide a roof panel provided with an integrated solar panel, which is at least substantially watertight or at least raintight at the upper side and on the sides. Any undesirable rainwater can be discharged from the roof panel via the opening at the bottom side of the panel, in such a manner that said rainwater can flow away over roof tiles disposed thereunder. The opening at the bottom side also

provides some ventilation, so that the temperature in the roof panel cannot run up (too) high when the roof panel is exposed to the blazing sunshine.

The object of the present invention is to provide a roof panel with an integrated solar panel as referred to in the introduction, with which a higher energy output can be realised under comparable conditions than with the known roof panel. This object is accomplished by the present invention in that at least one air outlet opening is provided in addition to said at least one opening present at the bottom side of the roof panel, so that in use at least one ventilation channel extends between the bottom plate and the solar panel from said at least one opening at the bottom side of the panel, which functions as an air inlet opening, to said at least one air outlet opening. Air that flows through said at least one ventilation channel cools the bottom surface of the solar panel, and thus the solar panel itself, resulting in an improved energy output of the solar panel in comparison with the solar panel in the known roof panel. The object of the present invention is thus accomplished. Small openings that may cause leakage currents may be present in the known roof panel. Think in this connection of screw holes or of a poor seal between the casing and the solar panel. Said openings cannot be regarded as a ventilation openings, of course, because the total area thereof does not suffice to make a (substantial) ventilation flow possible. If they would make a small airflow possible at all, the effect thereof would pale into insignificance when compared with the ventilation through the aforesaid (air inlet) opening at the bottom side of the known roof panel, through which some air could also flow out, of course. The ventilation means are designed to noticeably improve ventilation in comparison with the ventilation through the existing opening in the known roof panel. This is realised by enabling air to flow between two openings.

Said at least one air outlet opening is preferably provided in the casing of the roof panel. Air outlet openings can be easily provided in the casing, which air outlet openings, apart from ventilating of the solar panel, do no affect the operation thereof. In a preferred embodiment of the present invention, said at least one air outlet opening is provided in an upright wall of the casing. This enables air to flow along the surface of the solar panel and thus provide an adequate cooling of the solar panel.

If said at least one air outlet opening is provided in the upper upright

wall of the casing, this enables air to flow from the bottom side of the bottom surface to the upper side of the bottom surface, i.e. along the entire length of the solar panel. This ventilating airflow can thus cool the entire bottom surface of the solar panel. To prevent rainwater from flowing into the casing via the upper wall of the casing and reach the roof boarding, or at least impede such a flow of rainwater, it is preferable if the upper edge of said at least one air outlet opening in the upper upright wall of the casing slightly extends inwards into the casing. In this way a sort of lean-to is created, and the rainwater will fall on the bottom plate of the casing via the inwardly extending edge.

Alternatively, said at least one air outlet opening may be provided in the bottom plate of the casing. The casing is usually mounted on tile laths of the roof, so that sufficient space for enabling the airflow is present between the bottom plate of the roof panel and the lower part of the roof boarding. The tile laths function as spacers in that case. Because of this, a small amount of water might reach the roof boarding. This need not be a problem because such small amounts of water will not cause any leakage of the roof. To prevent leakage, however, casings not having any air outlet openings in the bottom plate may be provided for the lowermost roof panels. To provide a sufficiently large air outlet area and ensure a minimum required strength, it is preferable if the casing is provided with a series of air outlet openings. Said series may for example consist of a row of side-by-side air outlet openings in an upright wall. Connections between said openings impart strength to the casing. The present invention, according to a second aspect thereof, relates to a roof comprising at least two partially overlapping roof panels disposed one above the other, wherein said at least one air outlet opening in the lower roof panel of the two overlapping roof panels is unobstructed. Thus, air can flow out through the air outlet opening. In fact, the opening in question cannot be defined as an air outlet opening if the opening is obstructed by a higher roof panel or by a roof tile. After all, ventilation through an obstructed opening is not possible.

The present invention will be explained in more detail hereafter with reference to the appended figures, in which:

Figure 1 is a perspective view of a part of a tiled roof provided with

solar panels according to the present invention;

Figure 2 is a larger-scale detail view of the part Il in figure 1 ;

Figure 3 is a cross-sectional view along the line Ill-Ill in figure 1 ; and Figure 4 is another detail view of the roof panel of figure 1.

Figure 1 shows a perspective view of a part of a roof 1 comprising roof boarding with longitudinal battens 2 and tile laths 3. As the figure shows, roof tiles 4 and roof panels 5 according to the present invention provided with a solar panel 6 are present on the tile laths 3. Figure 2 shows a detail view of the part Il in figure 1. Roof panels

5a, 5b are mounted on the tile laths 3. The upper roof panel 5a partially overlaps the roof panel 5b disposed there below. The roof panels 5a, 5b comprise a metal casing 7a, 7b, respectively, a bottom 8a, 8b, respectively, and an upper upright wall 9. The solar panel 6a is supported inter-alia on the upright wall 9a and is held spaced from the bottom 8a at the bottom side of the roof panel 5a by means of a spacer 10a.

Figure 3 is a cross-sectional view along the line Ill-Ill in figure 1. Tile laths 3 are fixed to longitudinal battens 2, and on said tile laths 3 roof panels 5a, 5b and roof tiles 4 are provided. The roof panels have a metal casing 7 with a bottom 8 and an upper upright wall 9. Solar panels 6 are placed on the respective casings 7, which solar panels are supported on side walls 11 , brackets 12 and spacers 10. The roof tile 4 extends over the roof panel 5a beyond the upper upright wall. The roof panel 5a in turn extends over the roof panel 5b beyond the upper upright wall 9b.

Figure 4 shows a detail view comparable with the view shown in figure 2, in this case with partially cutaway roof tiles, however. The arrows Pb indicate an inlet air flow through the gap 15 between the metal casing 7 and the solar panel. The arrows Po indicate an outlet air flow between the solar panel 6 and the metal casing 7 and subsequently through the air outlet openings 13.

Referring now to the figures, there is shown a part of a roof 1 which is provided with two roof panels 5a, 5b disposed above each other. The roof panels 5a and 5b are of the BIPV-type and take the place of roof tiles on the roof 1. When air flows into a roof panel 5a, 5b through an air inlet opening 14 present therein, the air will flow upwards between the bottom 8 of the casing 7 and the bottom surface of the solar panel 6. In the embodiment that is shown in the figure, the air will exit the solar panel via the air outlet openings 13 at the upper side of the roof panel 5 and

flow into the roof construction under the roof tiles 4. While flowing upwards, the air flows along the bottom surface of the solar panels 6, thus cooling the solar panels. Because of the lower temperature of the solar panels 6 (in comparison with solar panels according to the prior art), a comparatively high energy output can be realised with the solar panels according to the present invention.

In the foregoing, the present invention has been explained with reference to one specific embodiment of the present invention. It will be understood that neither the drawings nor the description have a limitative effect on the scope of the present invention, which is defined in the appended claims. Many variants, which may or may not be obvious to the skilled person, are conceivable within the scope of the invention. Thus, air outlet openings are only present in the upper wall of the metal casing in the description and in figure 4. Air outlet openings may also be present elsewhere in the roof panel, however, for example in the bottom of the casing or in side walls thereof.