WO2002053990A1

WO2002053990A1 - Covering element for roofs and walls of buildings

Info

Publication number: WO2002053990A1
Application number: PCT/EP2001/014991
Authority: WO
Inventors: Francesca Nappini
Original assignee: Abb Service S.R.L.
Priority date: 2000-12-29
Filing date: 2001-12-18
Publication date: 2002-07-11
Also published as: ITMI20002872A1; IT1319741B1

Abstract

A covering element (1) for roofs and walls of buildings and the like, whose particularity consists of the fact that it comprises a panel which internally accommodates a coil (2) for the passage of a heat transfer fluid, the upper surface (5) of the panel, meant to be exposed to solar radiation (7), being transparent, at least one photovoltaic cell (6) being arranged below the coil (2), in order to receive the solar radiation (7) and convert it into electric power.

Description

COVERING ELEMENT FOR ROOFS AND WALLS OF BUILDINGS

DESCRIPTION

The present invention relates to a covering element for roofs and walls of buildings, having improved functionality. More particularly, the invention relates to a covering element that is suitable to provide a covering for roofs of buildings, having improved functionality.

It is known that roof coverings currently in use are generally constituted by roofing tiles, whose sole function is to protect the loft floor from atmospheric agents. Although said tiles perform the above cited protective task, they do not allow to produce electric power by utilizing solar energy or to convey light from the outside of the roof to the inside of the house.

Currently, when one wishes to obtain electric power from sunlight, one installs solar panels, which are placed on the top of the tiles, therefore as an addition to them, accordingly increasing the weight of the roof and the overall cost. Furthermore, in order to collect solar energy for lighting, heating and the like, it is necessary to provide alternative solutions to be combined with the existing roof tiles, such as for example skylights provided in said roof. In this case also, however, it is evident that providing an opening in the roof for conveying into the building the sunlight that arrives from outside is an expensive operation that is not simple to perform.

In particular, the use of solar energy that is incident on the ground has already been the subject of studies that have led to the provision of devices capable of collecting this energy. Specifically, said devices are: - photovoltaic cells, which directly convert the solar energy into electric power;

« solar panels, which use the solar energy to heat a heat transfer fluid, which is used in turn to produce sanitary hot water and/or to heat buildings.

For photovoltaic cells, conversion efficiency is low and therefore large surfaces are required in order to meet the average consumption of an apartment (for example 3 kW). Currently, the average dimensions of a panel that generates 50

W are approximately 1 m , and therefore 3 kW must be produced with approximately 60 m². Furthermore, these devices often must be placed over the existing covering of the roof, as explained earlier, and thus constitute an additional cost for new buildings.

Finally, the efficiency of the panel depends on its exposure, i.e. inclination with respect to the ground and the azimuth for the various latitudes. Usually, the panels are installed according to an "average" exposure, which means that their efficiency varies through the day.

The aim of the present invention is to provide a covering element for roofs and walls of buildings that allows to provide a modular covering with a plurality of integrated characteristics. Within the scope of this aim, an object of the present invention is to provide a covering element for roofs and walls of buildings that can replace currently existing tiles and internally integrates the heating, electric power generation, and optical guide functions.

Another object of the present invention is to provide a covering element for roofs and walls of buildings that is very rapid to assemble.

Another object of the present invention is to provide a covering element for roofs and walls of buildings that allows to reduce the overall cost of the roof provided by using said tiles.

Another object of the present invention is to provide a covering element for roofs and walls of buildings that is highly reliable, relatively simple to provide, and at competitive costs.

This aim, these objects and others that will become apparent hereinafter are achieved by a covering element for roofs and walls of buildings and the like, characterized in that it comprises a panel which internally accommodates a coil for the passage of a heat transfer fluid, the upper surface of said panel, meant to be exposed to solar radiation, being transparent, at least one photovoltaic cell being arranged below said coil, in order to receive said solar radiation and convert it into electric power.

Further characteristics and advantages of the invention will become apparent from the description of preferred but not exclusive embodiments of the covering element according to the present invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a schematic perspective view of the use of the covering elements according to the present invention;

Figure 2 is a schematic plan view of the structure of the covering element according to the present invention; Figure 3 is a schematic plan view of the covering element according to the present invention;

Figure 4 is a transverse sectional view of the covering element according to the present invention.

With reference to the above cited figures, the covering element according to the present invention, generally designated by the reference numeral 1, comprises a panel which is made of plastics and contains preferably at least one of the following devices; a mini solar panel, photovoltaic cells, optical guides. Essentially, the particularity of the element 1 resides in that it is capable of integrating in a single component systems capable of generating electric power, hot water and light, all this with small dimensions. The element 1 therefore comprises, as shown in Figure 2, a coil 2, which is provided with an inlet 3 for introducing a cold fluid, e.g. cold water and with an outlet 4 for discharging hot fluid, e. g. hot water. Said coil acts as a solar panel, since the upper surface 5 of the element 1 is transparent to incident solar radiation and is therefore capable of heating a heat transfer fluid that flows through the coil 2.

Conveniently, the element 1 is provided with photovoltaic cells 6, which are conveniently arranged below the coil 2, i.e., at the part of the covering element that is meant to be directed toward the inside of the building.

Essentially, the solar radiation 7 that strikes the element 1 follows the paths described hereafter:

- part of it is captured by an optical waveguide 10 and transferred as light to the inside of the building by means of a suitable circuit; - part of it passes through the transparent material 5 of the surface of the element 1, and a fraction of this part, designated by the reference numeral 11, does not affect the hot water generation circuit, i.e., the coil 2, while the remaining part 12 passes through said circuit.

Part of the fraction 11 that strikes the transparent material heats it and another part passes through it. The energy for heating the material is then absorbed by the heat transfer fluid contained within the coil 2. The portion that passes through the thickness of the element 1 is reflected by the lower surface of the covering element, which is conveniently parabolic, and is therefore concentrated onto the photovoltaic cells 6. All rays incident to a parabolic surface are in fact reflected onto a fixed point, i.e. the focus, where the cell is conveniently positioned. Said lower surface is advantageously coated with a layer of material that reflects sunlight.

Part of the fraction 12 that is incident to the hot water generation circuit (coil 2) is absorbed by said circuit, to generate hot water, and another part passes through it. This last part is treated like the fraction 11, since it is reflected by the lower parabolic surface of the element 1 and is directed onto the photovoltaic cells.

The pipes that constitute the coil 2 are conveniently shaped and elliptical, so that they themselves act as a magnifying lens, and therefore the radiation 7 is concentrated.

Essentially, the element 1 reduces the dimensions of current installations for the following reasons: - it does not require two different types of solar panel (electric and thermal panels), since these functions are included in the single panel that is provided;

- solar radiation is concentrated, and therefore a smaller number of photovoltaic cells 6 is needed to provide the same electric power generation;

- average efficiency increases, since the system is less sensitive to solar exposure, i.e., to the inclination with respect to the ground and the azimuth for the various latitudes.

Efficiency increases because the lower surface concentrates at the focus, i.e., at the position of the cells 6, radiation arriving from any direction. Accordingly, an increased exposure during daytime and in the various seasons is achieved. Fixed solar panels instead cannot have the same efficiency, since the angle of incidence of the solar radiation varies according to the time of day and the season.

The covering element thus conceived can of course be used for new buildings as roofing, or can be installed instead of conventional tiles, allowing to save weight and material, on the roof of a building or also on a vertical wall exposed to solar radiation.

Construction by means of plastic material in fact allows a low weight and, at the same time, a very high resistance to aging. The element 1 is furthermore provided with an optical output connector 20 and with a connector for drawing direct current 21.

Furthermore, the element 1 is of the modular type and can be installed on a roof, which must be provided with^' manifolds 25 arranged substantially parallel to each other so as to form a supporting structure for the individual covering elements 1.

The manifolds 25 constitute coupling points for the individual covering elements 1, which are provided with quick couplings.

The material of which each covering element is made must have the following characteristics: great resistance to aging, transparency to solar radiation, ability to absorb impacts (caused for example by hail) and ability to withstand considerable temperature variations.

In practice it has been found that the covering element according to the invention fully achieves the intended aim and objects, since it allows to integrate in a single structure the simultaneous generation of electric power, hot water and light.

The covering element according to the invention is extremely light and highly reliable and can easily replace existing tiles in order to provide roofing with a high integration of energy generation systems or on walls exposed to solar radiation.

The covering element thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

Claims

1. A covering element for roofs or walls of buildings and the like, characterized in that it comprises a panel which internally accommodates a coil for the passage of a heat transfer fluid, the upper surface of said panel, meant to be exposed to solar radiation, being transparent, at least one photovoltaic cell being arranged below said coil, in order to receive said solar radiation and convert it into electric power.

2. The covering element according to claim 1, characterized in that said coil is constituted by at least one pair of pipes arranged side by side and having an elliptical cross-section, at least one photovoltaic cell being arranged below said tubes.

3. The covering element according to claim 2, characterized in that the lower surface of said panel, arranged opposite said upper surface suitable to receive the incident solar radiation, has a parabolic shape at each one of said pipes and is covered with at least one layer of material suitable to reflect solar radiation.

4. The covering element according to one or more of the preceding claims, characterized in that said photovoltaic cell is arranged at the focus of said parabolic surface, opposite said transparent upper surface of said panel.

5. The covering element according to one or more of the preceding claims, characterized in that it comprises at least one waveguide suitable to receive said incident radiation and to transmit light from the surface of said panel that lies opposite said transparent upper surface.

6. The covering element according to one or more of the preceding claims, characterized in that it comprises an inlet for said cold heat transfer fluid and an outlet for said heat transfer fluid heated by the incident radiation.

7. The covering element according to one or more of the preceding claims, characterized in that it furthermore comprises an optical connector and an electrical power outlet for drawing electric current generated by said one or more photovoltaic cells.

8. The covering element according to one or more of the preceding claims, characterized in that it comprises quick couplings for engagement in a manifold to which said covering element is to be connected.

9. A roof or wall of a building and the like, characterized in that it comprises a plurality of manifolds suitable to form a supporting structure for a plurality of covering elements according to one or more of the preceding claims.

10. The roof or wall of a building according to claim 9, characterized in that each one of said manifolds comprises feeder and return pipes for said heat transfer fluid, electric cables and optical fibers.