US20080190412A1

US20080190412A1 - Device For Collectting Rainwater And Solar Energy Originating From Visible Radiation

Info

Publication number: US20080190412A1
Application number: US11/909,648
Authority: US
Inventors: Christian Cristofari
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-03-25
Filing date: 2006-03-24
Publication date: 2008-08-14
Also published as: FR2883588A1; EP1869267A1; WO2006100395A1; FR2883588B1

Abstract

Device for collecting rainwater and heat originating from solar radiation to both drain the rainwater and generate sanitary or heating hot water, capable of being fitted at the base of a roof or on the edge of a balcony, comprising an open channel 2 having longitudinal walls and side walls 7, 8, characterized in that a translucent or transparent covering element 3 is fitted inside the open channel 2, being maintained by the side walls 7, 8 and defining inside the open channel a watertight sealed chamber 2 b, in that a heat-exchanger device 12 inside which a heat-transfer fluid can circulate is fitted inside said sealed chamber 2 b, and in that the translucent covering element 3 defines, with at least a part of a longitudinal wall of the channel 2, a flow section for the rainwater.

Description

The subject of the present invention is a device for recovering rainwater and solar energy originating from light radiation. This collection device is intended for buildings and is able to be mounted at the base of a roof or on the edge of a balcony.
The importance that needs to be given to energy control is known, particularly in buildings, for developing solar devices capable of reducing the energy divide.
Solar energy can be recovered by using solar sensors generally positioned on the roof of the buildings. Inside these sensors a heat-transfer fluid is set in motion which can then be used to transmit the heat inside the rooms, for example by means of individual solar water heaters (ISWH) and/or floors fitted with passages for the heat-transfer fluid (sometimes called “direct solar floors” or COMBI).
Water- or heat-transfer fluid-based solar converters are known, generally made of metal or composite materials, comprising a bottom part consisting of a box, an insulator, an absorber and a collector and a top part consisting of a translucent or transparent panel thus providing a greenhouse effect. Also known are heat-transfer fluid-based solar converters made of metallic materials and of glass that can be used in vacuum operation.
Normally, these converter devices or solar sensors used in the buildings have a flat geometry (assemblies of vacuum modules or tubes for an area of 2 m×1 m for example) and have only a single functionality, to collect the heat deriving from the solar radiation.
The object of the present invention is to increase the efficiency of solar energy collection compared to the devices normally used, thus to increase the heat efficiency of these solar devices, and to propose a solar product that is fully integrated into the building, and having at least a dual function of rainwater recovery and collection of the energy deriving from the solar radiation.
Another object of the present invention is to provide a device that is lightweight, easy to fit and that can generate heat and/or electricity.
To this end, the present invention provides for the use of physical effects linked to the conversion of the solar radiation such as absorption and the greenhouse effect by using for its structure a collection device mounted on the base of a roof of a building or on the edge of a building balcony.
Heat recovery is achieved through a heat exchanger using the greenhouse effect, and which is installed on a sanitary or heating hot water production device. The collection device thus offers a dual function, being capable of both recovering the rainwater and recovering the solar energy to transmit it to a heat-transfer fluid which can be water or another fluid. Furthermore, depending on the coating of the heat-exchanger's absorber, it is also possible to generate electricity.
In one embodiment, the device for collecting rainwater and energy originating from solar radiation that makes it possible to both drain the rainwater and generate sanitary or heating hot water, or even electricity, can be mounted at the base of a roof or on the edge of a balcony and comprises an open channel having longitudinal walls and side walls.
A translucent or transparent covering element is fitted inside the open channel, being maintained by the side walls and defining, inside the open channel, a watertight sealed chamber.
A heat-exchanger device, inside which a heat-transfer fluid can circulate, is fitted inside said sealed chamber.
The translucent covering element defines, with at least a part of a longitudinal wall of the channel, a flow section for the rainwater.
In one embodiment, the translucent or transparent covering element comprises a plate defining, with a part of the longitudinal walls, the watertight sealed chamber.
Advantageously, the bottom part of the channel defines the watertight sealed chamber.
In another embodiment, the device also comprises at least one longitudinal bottom wall positioned in the open channel at a distance from a bottom wall of the channel, said longitudinal bottom wall forming the bottom of the watertight sealed chamber and partly delimiting the flow section for the rainwater.
The longitudinal bottom wall can be made of synthetic materials (polymer or composite type), glass, metal or alloy.
Advantageously, the longitudinal bottom wall extends from one of the internal longitudinal walls of the open channel to the vicinity of the opposite internal longitudinal wall so as to leave a space between said opposite internal wall and the longitudinal bottom wall.
In another embodiment, the translucent covering element is of generally tubular form.
Advantageously, the device comprises an additional trough positioned inside the open channel and partly surrounding the translucent covering element, said trough being covered by a reflecting element so as to increase the solar concentration effect inside the translucent covering element. The additional trough is preferably connected to one of the longitudinal walls of the open channel.
The absorber, which can have different inclinations according to the latitude of the installation site and the geometry of the device, ensures an optimum solar radiation concentration effect with a high efficiency.
The open channel and the side walls can be made of synthetic materials (polymer or composite type), glass, metal or alloy.
The open channel, over its part concerning the recovery of solar heat, has a translucent or transparent covering providing the greenhouse effect and can, in its bottom part, have an insulating plate.
The open channel, over its part concerning the evacuation of the rainwater, can be coated on the inside, with a reflecting coating so as to increase the solar concentration effect.
In a preferred embodiment, the heat-exchanger device consists of a metal plate, preferably corrugated, which serves as an absorber, and at least one metal pipe for carrying the heat-transfer fluid.
Preferably, the corrugated metal plate is coated on its top side with a selective black paint, a black coating produced by anodization, or a mono- or polycrystalline silicon type mineral coating, absorbing the heat optimally and radiating in the long wavelengths, so maximizing the greenhouse effect.
The metal pipe or pipes can be welded to the bottom side of the corrugated metal plate and fixed to the side walls of the open channel. The corrugated profile provides for a greater heat efficiency by concentration effect. There is advantageously a separation between the corrugated metal plate and the translucent or transparent covering, so favouring temperature rise inside the solar sensor part.
Advantageously, the metal plate is coated with at least one mineral to convert the radiation into electricity. The mineral coating can, for example, be silicon.
In another embodiment, the heat-exchanger device comprises at least one metal or composite synthetic material line welded fixed to the side walls and used to convey the heat-transfer liquid.
Preferably, the metal line(s) is/are covered with a selective black paint, a black coating produced by anodization, or a mono- or polycrystalline silicon type mineral coating, the lines made of composite synthetic material incorporate black monochromatic polymers, so absorbing the heat optimally and radiating in the long wavelengths, so maximizing the greenhouse effect.
There is a separation between the metal or composite synthetic material lines and the translucent or transparent covering, so favouring temperature rise inside the solar sensor part.
In an advantageous embodiment, the side walls can be interlinked by a simple join, fitted together, glued or welded, which can be provided, for expansion effects, with a polymer seal.
The watertight sealed chamber can form a controlled-atmosphere enclosure.

The invention will be better understood from studying particular embodiments described as by no means limiting examples and illustrated by the appended drawings, in which:

FIG. 1 is a top view of a first embodiment of a device according to the invention;

FIGS. 2, 3 and 4 are top views of individual modules intended to be assembled to form a second embodiment of a device according to the invention;

FIG. 5 is a section through V-V of FIG. 1 showing the internal structure of the device;

FIG. 6 is a section through VI-VI of FIG. 1;

FIG. 7 is a section through VII-VII of FIG. 2, showing the internal structure of the join of a module with another module or with a rainwater down connector;

FIG. 8 is a cross-sectional view through VIII-VIII of FIG. 1;

FIG. 9 is a section corresponding to the section of FIG. 5 showing the internal structure of a third embodiment of a device according to the invention;

FIG. 10 is a section corresponding to the section of FIG. 6 showing the internal structure of the third embodiment of a device according to the invention;

FIG. 11 is a section showing the internal join structure of a module of FIGS. 9 and 10 with another module of the same type or with a rainwater down connector to form a fourth embodiment of the invention;

FIG. 12 is a section corresponding to the section of FIG. 5 showing the internal structure of a fifth embodiment of the invention;

FIG. 13 is a section corresponding to the section of FIG. 5 showing the internal structure of a sixth embodiment of the invention;

FIG. 14 is a top view of a seventh embodiment of a device according to the invention;

FIGS. 15, 16 and 17 are top views of individual modules intended to be assembled to form an eighth embodiment of a device according to the invention;

FIG. 18 is a section through XVIII-XVIII of FIG. 14 showing the internal structure of the device;

FIG. 19 is a section through XIX-XIX of FIG. 14;

FIG. 20 is a section corresponding to the section of FIG. 18 showing the internal structure of a ninth embodiment of a device according to the invention;

FIG. 21 is a section corresponding to the section of FIG. 19 showing the internal structure of the ninth embodiment of the device according to the invention;

FIG. 22 is a section corresponding to the section of FIG. 18 showing the internal structure of a tenth embodiment of a device according to the invention;

FIG. 23 is a section similar to that of FIG. 18, illustrating a variant;

FIG. 24 is a section similar to that of FIG. 22, illustrating a variant;

FIG. 25 is a section corresponding to the section of FIG. 18 showing the internal structure of an eleventh embodiment of a device according to the invention; and

FIG. 26 is a section through XXIV-XXIV of FIG. 14.

A first embodiment of the device for collecting rainwater and energy originating from solar radiation is referenced 1 overall in FIGS. 1, 5, 6 and 8. The device 1 comprises an open channel 2, and a translucent or transparent covering element or plate 3 of generally rectangular form. The device 1 is here represented mounted on the edge of a roof 19 of a building, like a conventional gutter.
Of course, the positioning of the device 1 on the edge of a roof 19 is by no means exclusive, it would also be possible to consider mounting the device on the edge of a balcony.
The open channel 2 comprises on its two smallest sides, a flat side wall 7 of the same section as the section of the open channel 2, as illustrated in FIG. 8. The open channel 2 also comprises, on its opposite side, a flat side wall 8 of section delimited by a part of the section of the open channel 2 and by one of the fixing strips 4 of the covering plate 3, as illustrated in FIG. 7. The open channel 2 can comprise, in different sections, one or several transverse flat plates 9 of section delimited by a part of the section of the open channel 2 and by the bottom edge of the covering 3, as illustrated in FIG. 6, and this, in order to reinforce the mechanical strength of the device, and so ensure a good rigidity.
The translucent or transparent covering plate 3 is fixed on its edges 10 to the internal part of the open channel 2 and to the side walls 7, 8. Fixing strips 4 secure the covering plate 3.
The side wall 8 and the plates 9 provide support for the heat exchanger while the translucent or transparent covering plate 3 is supported by the side walls 7 and 8 and the plates 9.
FIG. 5 illustrates the internal structure of the device 1. The plate 3 defines, with the bottom part of the channel 2, a watertight sealed chamber 2 b. The watertight chamber 2 b is therefore defined by the covering element 3 and a part of the longitudinal walls of the open channel 2.
An insulating plate 11 can be fixed inside the channel 2. The plate 11 has the same profile as the open channel 2 and thus covers all the bottom of the chamber 2 b. A heat exchanger 12 is fitted in the chamber 2 b and comprises a corrugated metal plate 12 a on the bottom side of which are fixed, for example by welding, two metal pipes 5. As a variant, it would also be possible to consider providing a single metal pipe.
The two metal pipes 5 enable a heat-transfer fluid to flow according to the arrows 14 from one of the sides of the wall 8 to the wall 7 with a return to the wall 8, for example through a 180° return bend not shown in the figures.
The two pipes 5 of the heat exchanger 12 end in two nozzles 6 which project inside the channel 2 and can be connected respectively to a feed and extraction pipe, or even to a 180° return bend, not shown in the figures. These feed and extraction pipes can be incorporated in a rainwater downpipe. This option makes it possible to fully integrate the device 1 in the structure of the building. As a variant, just a single pipe could be used with nozzles located on both sides of the device.
To increase the heat efficiency, a reflecting coating can be applied to the part open to the air 2 a of the internal side of the open channel 2 (FIG. 5).
The collection device 1 illustrated in FIG. 1 can be divided up over its length to then present several collection modules joined to each other. Examples of such modules, referenced 1 a, 1 b and 1 c, are illustrated in FIGS. 2, 3 and 4, in which similar elements are given the same references. It is thus possible to produce long collecting lengths.
The part of the open channel 2 intended to convey rainwater according to the arrows 15, is here delimited by the part open to the air 2 a of the internal side of the open channel 2 (FIG. 5) and by the translucent or transparent covering plate 3. The rainwater is conveyed from the wall 7 to the wall 8 and rainwater is collected over the entire length of the device referenced 1 or of the various modules referenced 1 a, 1 b and 1 c.
A drip device 16 can be glued, welded or moulded on the bottom part of the open channel 2 (FIG. 5). A ventilation and evacuation orifice (not shown) can be provided through the side walls 7 and 8.
The material forming the channel 2 can be metal like that forming the heat exchanger 12. As a variant, the material forming the channel 2 can be a synthetic polymer or any other material appropriate for collecting rainwater. It would also be possible to consider providing a vacuum in the chamber 2 b.
Although the description has been given in relation to an exemplary embodiment where the heat exchanger comprises two flow and return passages for a heat-transfer fluid, it would also be possible to envisage a variant with just one heat-transfer fluid passage. It would also be possible to consider an absorber comprising a flat metal plate. The geometry of the profile of the open channel 2 is in no way essential and forms other than those illustrated could perfectly well be used.
The third embodiment of the water collection device illustrated in FIGS. 9 and 10 differs from the embodiments of the preceding figures in that the open channel 2 also comprises a longitudinal bottom wall 17 fixed to the side walls 7, 18 of the open channel 2, and a wall 21 extending said bottom wall 17 upward towards the transparent covering plate 3. Said covering plate 3 is fixed on its edges 10 to the walls 7, 18, 21 and to the internal longitudinal wall of the channel 2 located alongside the roof 19 of the building, with the fixing strips 4 securing the covering plate 3.
The bottom wall 17 extends from the internal longitudinal wall of the channel 2 located alongside the roof 19 of the building to the vicinity of the opposite internal longitudinal wall. The longitudinal bottom wall 17 is positioned in the open channel 2, distanced from the bottom wall of the channel. For example, the wall 17 can be fitted at mid-height of the channel 2. Said longitudinal bottom wall forms the bottom of the watertight sealed chamber 2 b, the wall 21 forming one of the sides of said chamber. Thus, the chamber is delimited by the walls 7, 18, 17 and 21, by the internal longitudinal wall of the channel 2 located alongside the roof 19 of the building, and by the covering plate 3.
The insulating plate 11 here has the same profile as that of the sealed chamber 2 b and covers the walls 17 and 21 and a portion of the longitudinal internal wall of the channel located alongside the roof 19 of the building.
The longitudinal bottom wall 17 leaves a space between the bottom wall of the channel and said wall 17. In a similar way, the wall 21 leaves a space between itself and the longitudinal internal wall of the channel located on the side opposite to the roof 19 of the building.
In other words, the watertight chamber 2 b is located in a top part of the channel 2, offset from the bottom and from the longitudinal internal wall of the channel located on the side opposite to the roof 19. Thus, the rainwater is conveyed on the translucent covering plate 3, but also between the wall 21 and the part open to the air 2 a of the internal wall of the open channel, and between the wall 17 and the bottom wall of the channel.
In this embodiment, the rainwater can thus flow over the translucent covering plate 3, over the side and under the chamber 2 b. The flow section for the rainwater is therefore significantly increased.
As illustrated in FIG. 10, in order to reinforce the mechanical resistance of the device and ensure a good rigidity, the open channel 2 comprises, in different sections, one or more transverse flat plates 20 delimited by the opposite longitudinal internal walls of the open channel 2. The covering 3 and the longitudinal bottom wall 17 bear on one of the front sides of said transverse plates 20.
So as to obtain long collecting lengths, the device illustrated in FIGS. 9 and 10 can be divided up over its length to present a number of collection modules joined to each other.
The internal structure of a join of one module to another module is represented in FIG. 11, which illustrates in section a flat side wall 18 of the device delimited by one of the fixing strips 4 of the covering plate 3, by the opposite longitudinal internal walls of the open channel 2. The bottom wall 17 bears on the front side of the plate 18.
The multiple-collection device according to the invention presents numerous advantages regarding its integration in the buildings, its bulk, its positioning, its weight since it can be modular and its enhanced performance by concentration effect. As a variant, it would also be possible to consider integrating the device in an existing gutter preferably having an identical profile and/or providing for a vacuum to be created in the chamber 2 b.
As a variant, it would also be possible to consider providing a different arrangement illustrated in FIG. 12, in which the similar elements are given the same references, wherein the bottom wall 17 extends from the internal longitudinal wall of the channel 2 located on the side opposite to the roof 19 of the building. The wall 21 leaves a space between itself and the longitudinal internal wall 22 of the channel located alongside the roof 19 of the building. In this variant, the chamber 2 b is delimited by the walls 7, 18, 17 and 21, by the internal longitudinal wall of the channel 2 located on the side opposite to the roof 19 of the building, and by the covering plate 3.
In a variant of embodiment illustrated in FIG. 13 in which the identical elements are given the same references, the chamber 2 b extends inside the open channel 2, leaving a space on either side between itself and the internal longitudinal walls of the channel, 2.
The chamber 2 b here comprises a wall 23 extending the bottom wall 17 upward, on the side opposite to the wall 21, towards the transparent covering plate 3. Thus, the wall 23 leaves a space between itself and the longitudinal internal wall 22 of the channel located alongside the roof 19 of the building.
In these conditions, the chamber 2 b is delimited by the walls 7, 18, 17, 21 and 23, and by the covering plate 3.
In order to reinforce the mechanical resistance of the device and ensure a good rigidity, it is possible to secure at least one of the walls 21 and 23 of the chamber 2 b with the corresponding wall of the channel 2, for example using spacers.
In the embodiment illustrated in FIGS. 14, 18 and 19 in which similar elements are given the same references, the device 1 comprises a tubular covering element or pipe 24 which is fixed at each of its free ends to the transverse flat walls 25 that are added at each end of the open channel 2. The pipe 24 is translucent or transparent.
The walls 25 are identical to each other and present a section partly delimited by the section of the open channel 2 but leaving a space between the bottom wall 2 a of the open channel 2 and their respective bottom edge in order to allow rainwater to flow in said channel.
In this embodiment, the internal side wall of the pipe 24 thus delimits the watertight sealed chamber 2 b, in this case cylindrical, inside which the heat exchanger 12 is fitted.
The variant of embodiment illustrated in FIGS. 20 and 21 differs from the preceding embodiment in that the open channel 2 also comprises an additional trough 26 extending inside said channel.
The trough 26 is provided with a rectilinear part 26 a extending, from a top free end of the longitudinal wall 27 opposite to the roof 19, towards the bottom wall 2 a, and a concave part 26 b oriented upward which prolongs the free end of the rectilinear part 26. The concave part 26 b presents a semi-circular profile. The concave part 26 b is configured so as to partly surround the bottom portion of the pipe 24, being located in the vicinity of said pipe 24. Inside the trough 26, the rainwater is thus partially drained.
Advantageously, the trough 26 is coated on its bottom part with a reflective covering (not represented) so as to increase the solar concentration effect inside the sealed chamber 2 b which is located above the concave part 26 b of the trough 26. In practice, in these conditions, the solar radiation directed towards the trough 26 is reflected to the chamber 2 b, which significantly increases the solar energy recovered by the device.
In other words, the design of such an additional trough 26 oriented upward, partly surrounding the pipe 24, and covered with a reflective material, makes it possible to increase the heat efficiency of the device 1.
In this variant of embodiment, the device 1 comprises transverse flat walls 27 which are added to each end of the open channel 2. The walls 27 are identical to each other and have a section delimited by the section of the open channel 2, but leaving a space between the bottom wall 2 a of the open channel 2 and their respective bottom edge in order to allow rainwater to flow inside the open channel 2 and inside the trough 26.
In other words, in section, the bottom edges of the plates 27 are offset upward relative to the bottom end of the trough 26.
In a variant of embodiment, the pipe 24 can also be provided with a cylindrical metal plate covering the internal side wall of said pipe and linked to the corrugated metal plate 12 a, and an additional external cylindrical side wall delimiting a sealed cylindrical chamber radially surrounding the internal side wall of the pipe 24 and the heat exchanger 12, said duly created additional chamber advantageously containing a vacuum. In other words, this vacuum chamber surrounds the sealed chamber 2 b.
The embodiment illustrated in FIG. 22 differs from the preceding embodiment illustrated in FIGS. 20 and 21 in that the trough 26 is connected to the channel 2 alongside the side wall 22 by a wall 29 extending the roof 19 outward so that the concave part 26 of the trough 26 partially bears against the side wall 22.
In the variant of embodiment illustrated in FIG. 23, a plurality of tubular covering elements 24 are placed side by side in the open channel 2. Apart from this particular feature, this variant is similar to that of FIG. 18.
In a variant of embodiment illustrated in FIG. 24, which is similar to that illustrated in FIG. 22, a plurality of tubular covering elements 24 are placed side by side in the open channel 2. Furthermore, the channel 26 has a number of concave parts 26 b, each surrounding a tubular covering element 24.
In the variant of embodiment illustrated in FIG. 25 in which similar elements are given the same references as in FIGS. 18 to 22, the trough 26 extends inside the open channel 2, leaving on either side a space between itself and the internal longitudinal walls of the channel 2. The trough 26 thus leaves a space between the concave part 26 b and the longitudinal wall 22, and between the rectilinear part 26 a and the opposite wall 2 a.
In order to reinforce the mechanical resistance of the device and ensure a good rigidity, it is possible to secure at least one of the parts 26 a and 26 b with the corresponding wall facing the channel 2, for example using spacers.
As illustrated in FIG. 26, in order to reinforce the mechanical resistance of the device 1, the open channel 2 advantageously comprises, in different sections, one or more transverse flat plates 29 of section delimited by the section of the open channel 2, but leaving a space between the bottom wall 2 a of the open channel 2 and their respective bottom edge in order to allow rainwater to flow inside the open channel 2 and inside the trough 26. The plates 28 also comprise a housing 30 for the pipe 24 to pass through.
With the invention, a device for collecting rainwater and heat originating from solar radiation is obtained, in which the watertight sealed chamber for collecting solar energy is fitted inside the open channel. The chamber is either partly delimited by a translucent covering plate or formed by a translucent pipe.
In other words, regardless of the embodiment of the invention, the device forms a combined compact assembly in which the collection of energy is performed in the channel provided for rainwater flow.
Furthermore, regardless of the embodiment, it may be particularly advantageous to provide an additional trough oriented upward, partly surrounding the watertight chamber which is either partly defined by the translucent covering plate, or delimited by the translucent pipe, and which is covered with a reflective material for increasing the heat efficiency of the device.
Moreover, the positioning of a channel oriented upward which is open over all its length makes it possible to obtain a device which provides this dual energy and rainwater collection function in a particularly simple and cost-effective way, while at the same time limiting the risk of water flowing outside of said channel.
The multiple-collection device according to the invention can be associated, like a conventional gutter, with downpipes via down connectors and, like a conventional solar sensor, with a regulation loop and a storage vessel or tank for storing the duly generated hot water, and/or with equipment using electricity for its operation.

Claims

1. Device for collecting rainwater and heat originating from solar radiation to both drain the rainwater and generate sanitary or heating hot water, capable of being mounted at the base of a roof or on the edge of a balcony, comprising an open channel (2) having longitudinal walls and side walls (7, 8), characterized in that a translucent or transparent covering element (3; 24) is fitted inside the open channel (2), being maintained by the side walls (7, 8) and defining, inside the open channel, a watertight sealed chamber (2 b), in that a heat-exchanger device (12), inside which a heat-transfer fluid can circulate, is fitted inside said sealed chamber (2 b), and in that the translucent covering element (3) defines, with at least a part of a longitudinal wall of the channel. (2), a flow section for the rainwater.

2. Device according to claim 1, in which the translucent or transparent covering element (3) comprises a plate defining, with a part of the longitudinal walls, the watertight sealed chamber (2 b).

3. Device according to claim 1 or 2, in which the bottom part of the channel (2) defines the watertight sealed chamber (2 b).

4. Device according to claim 1 or 2, also comprising at least one longitudinal bottom wall (17) positioned in the open channel at a distance from a bottom wall of the channel, said longitudinal bottom wall forming the bottom of the watertight sealed chamber (2 b) and partly delimiting the flow section for the rainwater.

5. Device according to claim 4, in which the longitudinal bottom wall (17) extends from one of the internal longitudinal walls of the open channel to the vicinity of the opposite internal longitudinal wall so as to leave a space between said opposite internal wall and the longitudinal bottom wall (17).

6. Device according to claim 1, in which the translucent covering element (24) is of generally tubular form.

7. Device according to any one of the preceding claims, comprising an additional trough (26, 26 b) positioned inside the open channel (2) and partly surrounding the translucent covering element, said trough being covered by a reflecting element so as to increase the solar concentration effect inside the translucent covering element.

8. Device according to claim 7, in which the additional trough (26) is preferably connected to one of the longitudinal walls of the open channel (2).

9. Device according to claim 6, in which a plurality of tubular covering elements (24) are placed side by side.

10. Device according to claims 7 and 9 taken together, in which the additional trough has several concave parts (26 b) each surrounding a tubular covering element (24).

11. Device according to any one of the preceding claims, divided up over its length and having several modules (1 a, 1 b and 1 c) joined to one another.

12. Device according to any one of the preceding claims, in which an insulating plate (11) is positioned on at least a part of the internal side of the longitudinal walls of the bottom part of the open channel (2) inside the watertight sealed chamber (2 b).

13. Device according to any one of the preceding claims, in which a reflecting coating is applied to the internal side of a part open to the air (2 a) of the longitudinal wall of the open channel (2).

14. Device according to any one of the preceding claims, in which one or several transverse flat plates (9), on which the bottom side of the covering element (3) bears, are fitted in the bottom part of the channel (2) to increase its rigidity.

15. Device according to any one of the preceding claims, in which the material forming the open channel (2) is different from that of the heat-exchanger device (12).

16. Device according to any one of the preceding claims, in which the heat-exchanger device (12) comprises a corrugated metal plate (12 a) on the bottom side of which is welded at least one metal pipe (5), in which the heat-transfer fluid circulates.

17. Device according to claim 16, in which the metal plate (12 a) is coated with at least one mineral to convert the radiation into electricity.

18. Device according to any one of the preceding claims, in which the watertight sealed chamber (2 b) forms a controlled-atmosphere enclosure.