EP2245380A1

EP2245380A1 - Solar energy system

Info

Publication number: EP2245380A1
Application number: EP09708130A
Authority: EP
Inventors: Arne Moberg; Peter Kjaerboe; Frederic Telander
Original assignee: Soltech Energy Sweden AB
Current assignee: Soltech Energy Sweden AB
Priority date: 2008-02-07
Filing date: 2009-02-06
Publication date: 2010-11-03
Also published as: ES1068955U; ES1068955Y; EP2245380A4; SE533796C2; SE0850011L; WO2009099390A1

Abstract

The present invention relates to a solar energy system comprising a space (1 ) in the roof or wall of a building, in which space a flowing medium may be circulated between an inlet opening (7) and an outlet opening (8). According to the invention several beams (9-13) are arranged in the flowing path of the medium between the inlet opening (7) and the outlet opening (8), which beams are permeable for the medium to allow flow of the medium between the inlet opening and the outlet opening.

Description

SOLAR ENERGY SYSTEM

TECHNICAL FIELD

The present invention relates to a solar energy system comprising a space in a roof or wall of a building, in which space a flowing medium may be circulated between an inlet opening and an outlet opening.

BACKGROUND OF THE INVENTION

Such a solar energy system is known from WO 02/33331 A1. The system known from this document comprises an outer layer of light permeable material and a light absorbing material layer, on which permeated light incides. Under the light absorbing layer an air filled space exists, in which the air is heated when light incides towards the light absorbing material layer. In the document is suggested an embodiment in which the light permeable material layer is built up by transparent elements, having the same shape as conventional roofing tiles. There is however no detailed description of such an embodiment in the mentioned document.

The object of the present invention is to improve a solar energy system according to above such that it may be extended over an entire roof or an entire wall, is easy to assemble on existing buildings as well as in production of new buildings and which allows assembly of light permeable elements with a similar appearance as conventional roofing tiles in the same manner as such. SUMMARY OF THE INVENTION

These objects are achieved by a solar energy system comprising a space in a roof or wall of a building, in which space a flowing medium may be circulated between an inlet opening and an outlet opening, characterised in that one or several beams are arranged in the flowing path of the medium between the inlet opening and the outlet opening, which beams are permeable for the medium to allow flow of the medium between the inlet opening and the outlet opening. Due to the fact that several beams are arranged in the space it is ensured that the light absorbing material layer, which outwardly delimits the space and lath, supporting the roofing tiles, receives the required support. Further the permeability of the beams implies that the medium may flow from the inlet opening to the outlet opening irrespective of the row of beams arranged in the space. Thereby is achieved that the solar energy system according to the invention becomes more flexible and can be adjusted to all the loads such as load of snow, load of person etc., which may arise during assembly and use of the solar energy system on existing buildings or in the production of new buildings. The possible size of the space is then limited only by roof size or wall size.

In a first preferred embodiment each medium permeable beam comprises an elongated first element, an elongated second element and a web provided with opening, which web connects the first and second elements with each other.

In a variant the web consists of a row of separated spacer elements, which for example have a circular or oval cross section.

In a second preferred embodiment each medium permeable beam is made of metal or composite material and comprises a base and two legs protruding from the base, which legs each comprises a number of openings.

Said space is delimited outwardly by a gas tight, light absorbing material layer. Inwardly the space is limited by a material layer, which may be constituted by a wall layer or roof layer in the building to which the solar energy system is assembled or a material layer added in connection to the installation of the solar energy system.

Said space may be arranged on the roof of a building and the medium permeable beams may extend from one base of the roof or from each of the bases of the roof in direction towards the roof ridge. The medium permeable beams may also extend horizontally instead of in the direction towards the roof ridge. In such an embodiment the distance between the roof trusses of the roof suitably constitutes a multiple of the distance between the spacer elements and the permeable beams are arranged in such a way in said space that a spacer element is located vertically above each roof truss. In a wall or on a roof the beam may also be assembled diagonally in order to constitute a supporting strut.

Said space is preferably divided into two subspaces between the inlet opening and the outlet opening, wherein the space containing the inlet opening is smaller than the space containing the outlet opening, and that a passage exists between the two subspaces, which passage is located in the opposite end of the subspaces relative to the inlet opening and outlet opening. By such a formation a self circulation of a flowing medium between inlet and outlet may arise in the space when light incides on the absorbing material layer.

DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the enclosed drawings, in which:

Fig. 1 schematically shows a perspective view of a space of a solar energy system according to a first preferred embodiment of the invention with removed light absorbing layer; Fig. 2 schematically shows a cross sectional view from the side of a part of the solar energy system;

Fig. 3 schematically shows a perspective view of a part of a medium permeable beam according to a second preferred embodiment;

Fig. 4 schematically shows a side view of the beam in fig. 3;

Fig. 5 schematically shows a cross sectional view along the line V-V in fig. 4;

Fig. 6 and 7 show the same views as in fig. 5 of beams, constituting variants of the beam in fig. 3;

Fig. 8 schematically shows a perspective view of a part of a medium permeable beam according to a third preferred embodiment, and

Fig. 9 shows a side view of the beam in fig. 8.

DESCRIPTION OF EMBODIMENTS

Fig. 1 schematically shows a space 1 of a solar energy system according to the invention. The space 1 is delimited laterally by beams 2, 3 or similar elements, upwardly by a roof ridge 4 or a beam depending on if the space is arranged in a wall or on a roof, downwardly by a board 5 of a base of a roof or by a beam 5, inwardly by a material layer 6 and outwardly by a light absorbing layer, not shown in fig. 1. Further the space comprises an inlet opening 7 and an outlet opening 8. The space 1 is filled by means of a suitable medium. If the medium in the space 1 is air, the openings 2 and 3 may be directly connected to the air inside the building, otherwise to inlets and outlets respectively of a heat exchanger or other type of heat absorbing component in an energy storing or energy emitting device. In the described embodiment the flowing medium is constituted by air. _,

5

Inside the space 1 a row of beams 9-13 is arranged. The beams 9-13 extend parallel to each other and to the short sides 2, 3 of the space. Further, the height of the beams 9-13 is equal to the distance between the internal material layer 6 and the light absorbing layer, which is necessary in order for them to fulfil their supporting function. Air may thereby not pass below or above the beams 9-13, apart from possible leakage flow which may arise due to irregularities or the like in the upper or under sides of the beams.

The beams 9-13 each constitute I-beams with an upper foot portion 14, and a lower foot portion 15 and a web 16. The web 16 of the beam 9 is provided with an opening 17 while the web of the beams 10-13 are provided with at least two openings 17. The only occurring opening 17 in the beam 9 is placed in the end of the beam being located distal to the inlet opening 7. The beam 9 divides the space 1 into a first subspace containing the inlet opening 7, and a second subspace containing the outlet opening 8. By this placement of the beam 9 with an opening 17 it is achieved that the air has to flow downwardly in the first subspace and through the opening 17 in the beam 9, which debouches into a lower part of the second subspace. Due to the fact that the second subspace containing the outlet opening 8 is larger than the first subspace containing the inlet opening a self circulation is achieved in the space 1 when light heats up the air in the space 1 so that a flow of air from the inlet 7 goes downwardly in the first subspace and flows into the other subspace through the opening 17 in the beam 9, after which the air in the second subspace flows towards the outlet 8. Due to the fact that the beams 10-13 contain at least two openings 17 each this air flow is not stopped towards the outlet 8 to any notable extent.

In the embodiment shown in fig. 1 the beam 9 containing only one opening is placed closest to the inlet opening 7, which give the smallest possible subspace and thereby biggest difference in size between the first and the second subspace. It is of course possible to instead allow the beam to change place with any of the other beams, e.g. beam 10 in figure 1 , in order to thereby change the relationship in size between the first and second subspace. In the shown example the beams 9-13 are placed such that they also fulfil a supporting function, e.g. by the supporting lath for the roofing tiles if the space 1 is located on a roof, and are therefore arranged on equal distance from each other. If another relationship in size is desired between the first and the second subspace than what is permitted by the supporting function of the beams it is of course possible to arrange on an optional place a beam with only one opening or which end does not reach all the way to the lower edge of the space 1 between the rest of the beams in the space. Such a beam would then only have a delimiting function and would thus not need to extend parallel with the rest of the beams. If such a merely delimiting beam is used all other beams in the space 1 should have at least two openings 17.

The beams 10-13 with two openings shown in fig. 1 are only shown as schematic examples. The webs 16 of these beams may have more openings 17 than the two shown in the figure and the openings may have a different shape, e.g. circular, oval, triangular, rectangular, etc., and other dimensions than shown in the figures. The web need also not be built up by a material piece out of which openings have been pressed or in other ways received, but may be built up by bars or similar elements, building a crossbar.

In fig. 2 a cross sectional view of a part of the solar energy system is shown in an embodiment, in which the space 1 is arranged on a roof. As mentioned earlier the space 1 is limited outwardly by a layer 18 of a light absorbing material, e.g. a black painted layer of metal, fibre cloth or other material. The layer 6 delimiting the space 1 inwardly may be a tongued and grooved sealing, board, masonite etc. or an isolating cloth or plastic layer. Further the beams 2, 9-13, 3 support a row of horizontally mounted supporting lath 19, on which the roofing tiles 20 are suspended. The roofing tiles 20 are transparent such that light inciding thereon goes through the roofing tiles and hits the light absorbing layer 18. The roofing tiles may for example be made of glass or plastic or another transparent material. When light hits the layer 18, which advantageously is black or has any other shade or colour, promoting light absorption, the light is transformed into heat, which is then emitted to the air in the space 1. By the different relationships in size between the first subspace and the second subspace a self circulation will begin when the temperature in the space exceeds the temperature in the space intended to be heated. Naturally it is possible to support this self circulation with one or more fans, which in addition gives the advantage that the start and progress of the air circulation may be optionally controlled.

In fig. 3-7 a second embodiment of beam 21 for use in the space 1 is shown. In fig. 3 a perspective view of a part of the beam 21 arranged between a light absorbing layer 18 and a material layer 6, for example a tongued and grooved sealing, in fig. 4 a part of the beam 21 is shown in a side view and in fig. 5 the beam 21 is shown in a cross sectional view. The beam 21 is constituted by a beam with an upper foot portion 22, a lower foot portion 23 and a web being constituted by a row of separated spacer elements 24, of which only one is shown in fig. 3. The beam shown in fig. 3 is horizontally arranged on a roof and extends across the entire width of the roof. In fig. 3 an upper U-shaped border 25 of metal is also shown, on which light permeable roofing tiles may be suspended and which replaces conventional supporting lath. By the occurrence of the horizontal border 21 under the light absorbing layer 18 the border 25 is given smaller dimensions than a conventional supporting lath, which results in the fact that it casts less shadow on the light absorbing layer than a conventional supporting lath. In order to allow runoff of possible water on the light absorbing layer the U-shaped border 25 is provided with a number of openings 27. If this U-shaped border is given the same colour or shade as the light absorbing layer 18 it absorbs light and visually melts together with the light absorbing layer.

A solar energy system in which the medium permeable beams 21 extend horizontally thus has the technical effect that supporting lath, arranged on these and on which supporting lath medium permeable roofing tiles may be suspended, may replace and be given smaller dimensions than a conventional supporting lath, which results in the fact that it casts less shadow on a light absorbing layer and therefore that the efficiency increases.

The upper and lower foot portions 22, 23 respectively, have in the embodiment shown bevelled edges such that they in cross section has the shape of truncated triangles with the tips turned towards each other. Thereby the pressure drop is reduced when air is flowing through the free spaces between the spacer elements 24. It is of course possible to give the upper and lower foot portions a different cross sectional shape, for example square or rectangular. The bevelled edges may even be given an arched shape.

The spacer elements 24 have in the embodiment shown a rectangular cross section, but also these elements may be given a different cross sectional shape. In fig. 6 a similar cross sectional view as in fig. 5 is shown as a variant of spacer elements 24', in which the edges of the spacer elements towards each other in cross section has a triangular shape. Other cross sectional shapes, such as arched shape, is conceivable. A spacer element with arched shaped edges turned towards each other may be formed such that its cross sectional shape becomes circular or oval. In fig. 7 a beam 21 , having spacer elements 24" with circular cross section is shown.

By horizontal placement of the beams 21 a separating element must naturally be arranged in the space 1 if it is desired to use the advantage of the self circulation of the air in the space, which arises by differently sized subspaces.

Beams 21 may naturally also be placed such that they extend from the roof base to the roof ridge instead of horizontally, such as the beams 9-13 in fig. 1. In such an arrangement of beams 21 a separating element is naturally needed, which either replaces one of the beams 21 or is placed between two of these. By such a placement of the beams 21 the spacer elements 24' may be shaped with a V-shaped cross section only on one of the edges facing each other, wherein the beams are arranged such that the V-shaped tip of the spacer elements is directed downwardly in the first subspace, where the gas is flowing downwardly, and upwardly in the second subspace, where the gas is flowing upwardly.

In fig. 8 and 9 a third embodiment of an air permeable beam 27 is shown suitable to be used in the space 1 in similar views as fig. 3 and 4. This beam 27 is made of metal and has an U-like shape with a base 28 and two legs 29, 30. The leg 30 forms in the embodiment an angle of 90° to the base 28 while the leg 29 forms a larger, obtuse angle to the base 28 than the leg 30. The legs 29, 30 are terminated by two folded out fastening flanges, which are used to fix the beam to the foundation, which for example may be constituted by a tongued and grooved sealing or by the roof trusses of the roof. Further the legs 29, 30 each has a row of arch like openings 31 , extending along the length of the beam 27. The shape and size of the openings 31 may be varied as well as their placement. For example they may be constituted by circular or oval openings, extending in a row or two or several rows displaced relative to each other along the length of the beam 27.

In the embodiment shown the beam 27 is extending horizontally across the width or the roof and a border 32 is fixed to the base 28 of the beam 27 with screws, extending through the intermediate light absorbing layer 18. Other fastening devices than screws or rivets may of course be used in order to join supporting lath (the border 32), light absorbing layer and beam 27. The border 32 has an L-shaped lower part 33 and an upper foot portion 34. One of the legs 35 of the L-shaped lower part 33 constitutes fastening part for fixing the border to the foundation while a row of openings 37 extend along the length of the border 32 in order to allow runoff of possible water flowing in between roofing tiles, which are supported by the beam 27 and border 32, and the light absorbing layer 18. The border gives the same advantages as the border 25, described with reference to fig. 3, compared to a conventional supporting lath. All the beams described may be arranged to extend from the roof base of a roof to its roof ridge or extend horizontally or alternatively diagonally. According to one embodiment according to fig. 3-7, where the beam is extending horizontally, the spacer elements should be arranged such that a spacer element ends up above each roof truss. For example the centre distance between the spacer elements may be adjusted to a centre distance of both 60 cm and 120 cm of roof trusses. Other distances between the roof trusses naturally give other centre distances between the spacer elements. Generally it can be mentioned that the distance between the roof trusses should be an integer multiple of the distance between the spacer elements.

In all the described embodiments the medium permeable beams in roof application are placed above the roof trusses, which is preferred. It is naturally also possible to instead place the beams under the roof trusses and let the spaces between the roof trusses constitute parts of the space 1.

In the described embodiments the space 1 may be formed on existing roof constructions and the described beams constitute additional or replacement beams to already existing construction elements. In the production of new buildings however the space 1 may be provided in an easy way by the fact that the roof trusses are constituted by permeable beams according to any of the embodiments, e.g. the beams 2, 3, 9-13 may constitute roof trusses in a newly produced building. Naturally the beam dimensions need to be adjusted to the loads being supported.

The medium permeable beams in fig. 1-7 may be made of wood, metal while the beam according to fig. 8 and 9 is made of metal. It is also conceivable to use plastic or composite material. The light absorbing layer may be constituted by black painted sheet metal or a fibre fabric coated with a thin layer of metal and on top of this a thin layer of dark colour. A layer based on fibre fabric is preferred due to assembly and handling reasons. Other flexible materials than fibre fabric may be used in a light absorbing layer coated with metal and colour layers. The described embodiments may naturally be varied within the frame of the invention, especially with reference to shapes of the elements forming part of the beams. For example U-beams with short legs may be used in the embodiment shown in fig. 1 instead of I-beams. Also tubular beams with medium permeable opposite sides may be used. Further, the legs in the beam shown in fig. 8 may form the same angle with the base and not different angles. Even though the description of the embodiments primarily have been focused on roof application of the solar energy system, this may also be applied on walls. The flowing medium need not be constituted by air, although this is preferred, but may be constituted by another gas or a gas mixture or a liquid medium, for example water. If other media than air is used higher demands on impenetrability of the space are required. Further the inlet and/or outlet opening may consist of more than one opening and more than one space 1 may be arranged on one roof or one wall. The invention should therefore only be limited by the content in the enclosed claims.

Claims

1. Solar energy system comprising a space (1) in the roof or wall of a building, in which space a flowing medium may be circulated between an inlet opening (7) and an outlet opening (8), characterized in that several beams (9-13; 21 ; 27) are arranged in the flowing path of the medium between the inlet opening (7) and the outlet opening (8), which beams are medium permeable to allow flow of medium between the inlet opening and the outlet opening.

2. System according to claim 1 , in which each medium permeable beam comprises an elongated first element (14; 22), an elongated second element

(15; 23) and a web (16; 24; 24'; 24") provided with an opening, said web connecting the first and second elements to each other.

3. System according to claim 2, in which the web is constituted by a row of separated spacer elements (24; 24'; 24").

4. System according to claim 3, in which the spacer elements have circular or oval cross section.

5. System according to claim 1 , in which each medium permeable beam (27) is made of metal or composite material and comprises a base (28) and two legs (29, 30) extending from the base, which legs each comprises a row of openings (31).

6. System according to any of claims 1-5, in which said space (1) is outwardly delimited by a gas tight, light absorbing material layer (18).

7. System according to claim 6, in which said space (1) is arranged on the roof of a building and the medium permeable beams (9-13; 21 ; 27) extend from the base of the roof or each base of the roof in direction towards the roof ridge.

8. System according to claim 6, in which said space (1) is arranged on the roof of a building and the medium permeable beams (9-13; 21 ; 27) extend horizontally.

9. System according to claim 2 or 3, and 6 and 8, in which the distance between the roof trusses of the roof constitute a multiple of the distance between the spacer elements (24; 24'; 24") and the medium permeable beams (21) are so arranged in said space (1) that a spacer element is located vertically above each roof truss.

10. System according to any preceding claim, in which said space (1) is divided into two subspaces between the inlet and outlet opening, wherein the space containing the inlet opening (7) is smaller than the space containing the outlet opening (8), and that a passage (17) exists between the two subspaces, which passage is located in the opposite end of the subspaces relative to the inlet opening (7) and outlet opening (8).