WO1998008117A1

WO1998008117A1 - Lens tile and solar energy system

Info

Publication number: WO1998008117A1
Application number: PCT/AT1997/000187
Authority: WO
Inventors: Johann Windholz
Original assignee: Johann Windholz
Priority date: 1996-08-16
Filing date: 1997-08-13
Publication date: 1998-02-26
Also published as: AU3840697A

Abstract

This invention concerns a lens plate (1) in the form of a one-piece, rectangular, homogeneous glass plate out of colorless optical glass, Plexiglas, or some similar substance, in which a plurality of lenses (2) of the same form and optical configuration have been pressed in. One of the two surfaces of the plate (1) is configured flat or with only slight indentations or protuberances in the corresponding lens areas. To obtain a high concentration of sun light and good protection against weathering upon use in a solar energy system (7), the invention provides that the lenses (2) be placed behind and next to one another in a grid layout, when viewed from above, without intermediate spaces between the single lenses (2).

Description

Lens plate and solar system

The invention relates to a lens plate in the form of a one-piece, rectangular, homogeneous glass plate made of colorless optical glass, acrylic glass (plexiglass) or the like, in which a plurality of lenses of the same shape and optical configuration is incorporated by pressing, one of the two surfaces of the plate being flat or is designed with only slight indentations or bulges in the corresponding lens areas. Furthermore, the invention relates to a method for producing such a lens plate and its use in solar systems. In particular, the invention also relates to a solar system with a lens plate attached to a housing and having a plurality of lenses, under which there is a unit to be irradiated with the concentrated light.

A comparable lens plate and a method for its production are known from GB 150 736 A. Partly the same, partly differently shaped lens elements are produced on a band of glass, which are spaced from each other; however, after the glass has solidified, the lens elements are broken out in order to obtain individual lenses, with subsequent processing of the lenses by grinding and polishing being necessary in order to remove the superfluous edge regions.

Various devices for concentrating sunlight on the solar elements of these systems are known in the field of solar systems. Either reflector or lens systems are used for this, the solar element being designed either as a solar collector for hot water or hot air preparation, or as a solar cell for generating electricity.

For example, a solar system for heating water is known from DE 29 07 245 A; As a cover for the housing of the solar system, a lens plate is provided, which consists of a plurality of convex cylindrical lenses crossing one another at right angles, which are joined together, so that virtually individual square converging lenses are formed at the crossing points of the cylindrical lenses, which more sunlight or less cruciform on the top of a box-shaped container located under the lens plate in the housing, in which the water to be heated circulates. However, this construction is not very efficient in terms of sunlight concentration and is prone to dust accumulation in the gaps between the cylindrical lenses. In order to protect the lens plate against weather influences such as dust, rain and snow, a flat glass plate should be arranged in front of the lens plate. However, this results in a further reduction in the usable light radiation by absorption in or reflection on the glass plate.

From DE 27 12 913 A a solar system is known in which circular lenses are arranged in rows and columns at a distance from one another in a cover plate of a metallic housing, the focal point of which lies on the top of an intermediate plate arranged in the housing, which together with the Bottom and the side walls of the housing forms a chamber in which a gaseous or liquid heat carrier to be heated circulates. Due to the opaque areas of the cover plate located between the lenses, only a portion of the incident light radiation can be used.

From GB 2 277 198 A a solar system with a lens plate is known which consists of concave-convex cylindrical lenses, which are lined up next to one another in order to concentrate the light beams in strips on elongate semiconductor elements which are designed as a combination of a voltaic element with a Peltier element.

Furthermore, from DE 1 089 018 B cylinder lenses are known which are arranged above voltaic elements.

US Pat. No. 5,409,550 A and US Pat. No. 5,123,968 A disclose solar systems with voltaic elements which are arranged in rows and columns at intervals, circular Fresnel lenses being incorporated in a lens plate in plan view to focus the light beams. The areas of the lens plate lying between the lenses do not contribute to the focusing, so that a reduced optical efficiency results.

A solar system for generating warm air has become known, for example, from DE 29 43 159 A. This solar system consists of a box-shaped housing with a frame, from the top of which a glass plate is attached as a lid is. A corrugated sheet-shaped absorber plate is arranged below the glass plate, below which there is an oblique radiation plate with holes which lie exactly below the troughs of the absorber plate. At the higher end of the radiation plate there is an air inlet in the frame and an air outlet is provided at the lower end, the air being blown in under pressure.

The object of the invention is to provide a lens system in the form of a lens plate which, in addition to its optical suitability for efficiently concentrating sunlight on solar elements, also has good protection against the effects of weather, in particular also hailstorm, and can be produced with little effort. It is also an object of the invention to provide an inexpensive method for producing such a lens plate. It is also an object of the invention to propose a solar system in which the lens plate enables optimal optical efficiency when using the light radiation and withstands weather influences without impairing the optical efficiency.

The lens plate according to the invention of the type mentioned at the outset is characterized in that the lenses are lined up one behind the other and side by side in a top view in grid form, without any spaces between the individual lenses. Through these measures in the sense of an extremely dense arrangement of the lenses, the above-mentioned objective can be met well, because due to the close bundling of light and the good illumination of the gaps, an optimal use of the available surface of the lens plate for concentrating the sunlight on the Solar elements is given. Furthermore, a compact, stable structure of the lens plate is obtained, which ensures good protection against mechanical stresses and weather influences.

According to a preferred embodiment of the invention it is provided that all lenses are either plano-convex, concave-convex or biconvex, and that the thickness of the lens plate, measured between the individual lenses and in the edge areas, is at least 5 mm. On the one hand, this ensures a good optical concentration of the light rays on the solar ment and on the other hand ensures a high mechanical strength of the lens plate.

In practice, it has proven to be particularly advantageous if 720 lenses are provided on an area of 970 mm × 450 mm, the lens diameter of which is between 24 mm and 50 mm. This dimensioning is particularly suitable for existing solar systems for retrofitting and for systems in modular construction.

It is also advantageous if the focal length of the lenses is between 50 mm and 70 mm. This enables a particularly space-saving and compact unit of lens plate plus solar element to be achieved.

In order to achieve an even better weather resistance of the lens plate, it is advantageous if the glass is thermally hardened by quenching.

An advantageous, economical method for producing the lens plate according to the invention by pressing a mass of glass or plastic is characterized in that the molten mass is pressed in a manner known per se between hollow, water-cooled rollers, the spacing of which corresponds to the thickness of the lens plate, and into a subsequent one Cooling channel passed, cooled and relaxed, if necessary thermally hardened and then divided into plates. This method has proven to be particularly useful and inexpensive.

As already mentioned, the lens plate according to the invention is used particularly advantageously in solar systems for solar power generation, hot water preparation or warm air preparation.

A particularly advantageous solar system of the type mentioned at the outset is characterized in that the lens plate is formed with planar-convex or concave-convex lenses which adjoin one another in rows and columns without gaps, and in plan view, and in that the lenses with their flat or concave side face outwards are arranged. With this design, practically said surface of the lens plate can contribute to radiation focusing; in addition, a build-up of dust, rain, etc. on the flat or concave top of the lens plate is largely avoided, and also a any cleaning of the lens plate is made possible quickly and easily.

With regard to a compact design of the solar system with a relatively low overall height, it has proven to be advantageous if the lenses have a side length of 24 mm and a focal length of 50 to 70 mm. As a result, a large number of lenses with a relatively short focal length per unit area can be arranged in the solar system.

For the optional generation of electrical current, or for hot water preparation or for warm air preparation, it is provided that a voltaic module, an absorber container, or an absorber metal plate is arranged under the lens plate.

A structurally advantageous embodiment of the solar system is characterized in that the lens plate is held in groove-shaped recesses at the upper end portion of a frame forming the housing, which is closed at the bottom by a base plate. This enables simple assembly or disassembly of the lens plate or the voltaic module, the absorber container, or the absorber plate.

A particularly useful embodiment of the solar system also consists in that the frame has laterally led protrusions which are arranged at an end portion of the frame. This makes it possible to build or install the solar system on or in a load-bearing surface.

In the case of using the solar system for warm air preparation, it is particularly advantageous if the absorber metal plate is designed as a corrugated sheet and that the cones of light bundled by the lenses are directed onto the corrugations of the corrugated sheet. It is furthermore advantageous if bores are provided in the corrugation troughs of the corrugated sheet for extracting the warm air to a suction connection in the base plate. These measures can further increase the heat exchange effect between the corrugated sheet and the air to be heated.

The invention is explained in more detail below on the basis of preferred exemplary embodiments illustrated in the drawing, to which, however, it should not be restricted. Show it:

Fig.l shows a detail of a lens plate in plan view; 2 shows a detail of a lens plate according to Fig.l with plano-convex lenses in side view;

3 shows a detail of a lens plate according to Fig.l with concave-convex lenses in side view;

4 shows a single lens with areas omitted in the dense arrangement in the lens plate in comparison to a conventional round lens;

5 shows a single concave-convex lens together with the associated solar element in a side view;

6 shows a single plano-convex lens in a perspective view;

7 shows a perspective view of a solar system;

8 shows part of a solar system for generating electricity on average;

9 shows part of a solar system for hot water preparation on average; and

Fig.10 a part of a solar system for warm air preparation on average.

In Fig.l to 3, 1 generally designates a rectangular lens plate in plan view, which consists of a plurality of individual lenses 2 of square shape. The length L of the lens plate 1 is 970 mm and its width B is 450 mm, with an upper and lower edge B1 of 9 mm each, and a left and right edge B2 of 5 mm each to the lenses 2. This results in an area A occupied by the lenses 2 of 960 mm × 432 mm (approx. 0.4 m ² ), on which 720 square lenses 2 with a side length S of 24 mm are accommodated.

2 shows a lens plate 1 with an arrangement of plano-convex lenses 2, arrows L showing the direction of the incident sun rays. The lenses 2 arranged in rows and columns without a space have a thickness D of at least 5 mm at their abutments or edge regions. The radius Rl of the convexly curved surface is chosen so that a focal length of the lenses 2 of 50 to 70 mm results.

In the lens plate 1 shown in FIG. 3, concavo-convex lenses 2 are provided, the radius of the convexly curved surface again being denoted by R1 and the radius of the concavely curved surface by R2. Here, too, the radii R1, R2 are selected so that they have a focal length of 50 to 70 mm becomes .

There is of course also the possibility that the lenses 2 are biconvex.

FIG. 4 shows a single lens 2 as a “cutout” of a fictitious round lens with a diameter D of 33 mm, the circular segments which are omitted being designated by 4.

5 shows a concave-convex lens 2 together with a solar element 5 of a solar system, the solar element 5 being either a solar collector for hot water or hot air preparation or a solar cell for generating electricity; a light cone 6 emanating from the lens 2 is directed onto this solar element 5.

The individual plano-convex lens 2 shown in FIG. 6 shows its structure in a particularly clear manner.

Colorless optical glass, acrylic glass (plexiglass) or the like is provided as the material for the lens plate 1, the lens plate being produced by pressing a mass of glass or plastic between two embossing rollers in such a way that the molten mass is known between hollow, water-cooled rollers, the distance of which corresponds to the thickness of the lens plate, is pressed through. The web thus obtained is then passed into a subsequent cooling channel, cooled and relaxed, optionally thermally hardened and finally divided into plates.

The lens plate according to the invention is intended for use in optical solar systems for power generation, hot water or hot air preparation.

7 to 10, for example, 7 generally designates a solar system with a box-shaped metallic housing 8 on the lens plate 1 which forms the upper side of the housing and, as described above, consists of seamlessly and grid-shaped square lenses 2. The lenses 2 have a side length of 24 mm, so that a total of 720 lenses 2 can be arranged with a width of 450 mm and a length of 970 mm of the lens plate 1.

The solar system 7 shown in FIG. 8 is used to generate electricity and for this purpose has a voltaic module 9 which is arranged at a distance from the lens plate 1 in the bottom region of the housing 8. Cable connections for the voltaic module 9 are included Designated 10.

The housing 8 consists of a frame 11 forming the four side walls of the housing 8 and a base plate 13 fastened to the frame 11 by means of screws 12. The lens plate 1 is positively held in groove-shaped recesses 14 of the frame 11 at the upper end portion of the frame 11. Likewise, the voltaic module 9 is positively held in groove-shaped recesses 15 in the lower end section of the frame 11.

The lenses 2 of the lens plate 1 are, for example, plano-convex and have a corresponding radius R in order to achieve a focal length of 50 to 70 mm. The incident solar radiation 16 is bundled by the lenses 2 to form a light cone 17, which is directed at the individual solar elements (not shown in detail) of the voltaic module 9.

8, strip-shaped projections 18 with a bore 19 for receiving fastening screws (not shown) are provided on the side of the frame 11 for fastening or anchoring the housing 8 to a load-bearing surface; the projections 18 are optionally attached either in the lower or in the upper end section of the frame 11, depending on whether a construction or an installation of the solar system 7 on or in the ground is planned.

The solar system 7 shown in FIG. 9 is used for hot water preparation; For this purpose, an absorber container 20 is arranged at a distance from the lens plate 1 in the bottom region of the housing 8 as a heat exchanger unit, with an inlet 21 through the bottom plate 13 for the water to be heated and an outlet (not shown) for the heated water, the absorber container 20 in same as the voltaic module 9 in the solar system 7 according to FIG. 8 in a recess 15 of the frame

11 is supported. Likewise, the lens plate 1 is held in the recess 14 of the frame 11, the lenses 2 being concavo-convex and having a focal length of 50 to 70 mm. In turn, strip-shaped projections 18 are provided for mounting the solar system 7 according to FIG.

Finally, the solar system 7 shown in FIG. 10 is used for warm air preparation; an absorber metal plate 22 in the form of a corrugated sheet 23 is arranged at a distance from the lens plate 1 in the bottom region of the housing 8 as a heat exchanger unit, which is held in the same way as the voltaic module 9 in the solar system 7 according to FIG. 8 in a recess 15 of the frame 11; the base plate 13 has an opening 24 into which a suction nozzle 25 for the heated air is inserted. The air to be heated flows in via an inlet connection (not shown) arranged above the corrugated sheet 23 in the frame 11 and passes through bores 26 in the corrugated sheet 23 into the space below the corrugated sheet 23, from where it reaches the suction connection 25. The bores 26 are provided in the corrugation troughs 27 of the corrugated sheet 23, and the air is extracted from the suction connection 25 by means of a fan (not shown). The corrugated sheet 23 is oriented or held in such a way that the light cones 17 bundled by the lenses 2 are directed or focused onto the wave crests 28 of the corrugated sheet 23.

In the solar system 7 shown in FIG. 8, the flat sides of the lenses 2 form the upper side of the lens plate 1, while in the solar systems shown in FIGS. 9 and 10, concave sides of the lenses 2 form the upper side of the lens plate 1, whereby in both cases a easy and simple cleaning of the top of the lens plate 1 can be done.

Claims

Claims:

1. lens plate (1) in the form of a one-piece, rectangular, homogeneous glass plate made of colorless optical glass, acrylic glass (plexiglass) or the like, in which a plurality of lenses (2) of the same shape and optical configuration is incorporated by pressing, one of the two Surfaces of the plate (1) is flat or with only slight indentations or bulges in the corresponding lens areas; characterized in that the lenses (2) are arranged one behind the other and side by side in a plan view in a raster form directly, without gaps between the individual lenses (2), (Fig.l).

2. Lens plate according to claim 1, characterized in that all lenses (2) are either plano-convex, concave-convex or biconvex, and that the thickness (D) of the lens plate (1), measured between the individual lenses (2) and in the edge areas, is at least 5 mm.

3. Lens plate according to claim 1 or 2, characterized in that 720 lenses (2) are provided on an area of 970 mm x 450 mm, the lens diameter between 24 mm and

Is 50 mm.

4. Lens plate according to one of claims 1 to 3, characterized in that the focal length of the lenses (2) is between 50 mm and 70 mm.

5. Lens plate according to one of claims 1 to 4, characterized in that the glass is thermally hardened by quenching.

6. A method for producing a lens plate according to one of claims 1 to 5, by pressing a mass of glass or plastic between two embossing rollers, characterized in that the molten mass in a known manner between hollow, water-cooled rollers, the distance between the thickness of the Corresponds to the lens plate, pressed through and into a ß cooling channel passed, cooled and relaxed, if necessary thermally hardened and then divided into plates.

7. Use of the lens plate according to one of claims 1 to 5 in optical solar systems (7) for solar power generation, hot water preparation or hot air preparation.

8. Solar system (7) with a lens plate (1) attached to a housing (8) and having a plurality of lenses (2), under which there is a unit (9; 20; 22) to be irradiated with the concentrated light in the housing (8) located, characterized in that the lens plate (1) is designed according to one of claims 1 to 5.

9. Solar system (1) with a housing (8) attached lens plate (1), under which in the housing (8) is a unit to be irradiated with the concentrated light (9; 20; 22), characterized in that the Lens plate (1) is formed with rows and columns seamlessly adjoining, in plan view square, plano-convex or concave-convex lenses (2), and that the lenses (2) are arranged with their flat or concave side facing outwards.

10. Solar system according to claim 9, characterized in that the lenses (2) have a side length of 24 to 50 mm and a focal length of 50 to 70 mm.

11. Solar system according to one of claims 8 to 10, characterized in that a voltaic module under the lens plate (1)

(9) is arranged.

12. Solar system according to one of claims 8 to 11, characterized in that an absorber container (20) is arranged under the lens plate (1).

13. Solar system according to one of claims 8 to 10, characterized in that an absorber metal plate (22) is arranged under the lens plate (1).

14. Solar system according to one of claims 8 to 13, characterized in that the lens plate (1) in groove-shaped recesses (14) at the upper end portion of a housing (8) forming frame (11) is held, which is on the underside by a base plate (13) is completed.

15. Solar system according to claim 14, characterized in that the frame (11) has laterally strip-shaped projections (19) which are arranged on an end portion of the frame (11).

16. Solar system according to one of claims 13 to 15, characterized in that the absorber metal plate (22) is designed as a corrugated sheet (23), and that the cones of light (17) bundled by the lenses (2) on the crests (28) of the corrugated sheet (23) are directed.

17. Solar system according to claim 16, characterized in that in the troughs (26) of the corrugated sheet (23) bores (26) for extracting the warm air to an extraction nozzle (25) in the base plate (13) are provided.