DE102008001640A1 - Photovoltaic concentrator for concentrating sunlight for use in e.g. photovoltaic panel, has mirror component allowing incident light to be deflected onto absorbing element that is statically mounted with respect to mirror component - Google Patents

Abstract

The concentrator (100) has a statically mounted channel or trough-shaped mirror component (10) for allowing incident light i.e. sunlight, to be deflected onto a photovoltaic absorbing element (20), a solar cell, a solar cell plate or a solar cell bar. The absorbing element is statically mounted with respect to the mirror component. A massive optically transparent body (50) or a hollow body is filled with gas e.g. air, or with fluid e.g. water. The mirror component and a cooling device are integrated into the body. The mirror component is covered by an optically transparent cover plate. The cover plate is made of acryl or glass.

Description

Technical area

The present invention relates to a device for concentrating incident light, in particular of sunlight, provided, comprising at least one statically mounted trough or trough-shaped mirror body, by means of which the incident light on at least one photovoltaic absorber means, in particular at least one solar cell, for example at least a solar cell plate or at least one solar cell latch, is deflectable. (see document DE 202 20 390 U1 from the prior art).

State of the art

conventional Planar photovoltaic systems in use today have large-area silicon modules and are very expensive to manufacture, with production costs currently more than fifty percent by the cost of Silicon are intended.

Out For this reason, photovoltaic concentrators are increasing in recent times for use; Here, as concentrators of the light bundling serving devices of geometric optics, means derer a multiplication of the radiation density and thus a minimization of absorber losses can be achieved.

by virtue of the increased efficiency of photovoltaic systems can reduce the silicon cost by a reduced area of solar cells and thus the ratio of solar cell costs to the total costs be lowered.

such built up with lenses and / or with mirrors of various kinds Although concentrator systems reduce the problem of high silicon costs by the concentration factor of the concentrator (factor 10 up to Factor 1,000); However, such concentrator systems are with a connected much higher mechanical effort, because this Type of light concentration requires a relatively complex mechanical Tracking.

At least in Central and Northern Europe, such concentrators have due to the cloudy climate there has not yet been enforced because Concentrators mainly use direct radiation. Although the proportion of diffuse radiation in the total radiation can be up to fifty percent, the diffuse remains Radiation at least in tracking concentrators mostly unused.

in this connection becomes primary with regard to the design of photovoltaic concentrators between static systems and tracked systems distinguished. Static concentrators are as usual Flat or planar collectors permanently mounted, but have a design-related a concentration ratio that increases with the acceptance angle of the Radiation decreases.

By the big acceptance angle is with static photovoltaic systems however, limited use of the diffused light is possible. Typically, the concentration ratio is one-dimensional static concentrators in the range up to about 2. For this reason are the space requirements and the production costs related to the Concentration factor relatively high.

tracked Photovoltaic systems reach concentration factors of over 100, but this is a very elaborate Mechanics and control required; this is especially true for biaxial tracked systems, so that the development of such tracked photovoltaic systems mainly limited to large systems.

By the high wind load is with tracked photovoltaic systems a stable support required so that tracked Concentrators typically require a large area and hardly possible integration in buildings is.

Even though even diffused light creates a certain brightness in the concentrator, can also be highly concentrated tracking Photovoltaic systems barely use this diffuse radiation and are suitable thus mainly for sunny climates, for example in southern Europe.

in principle can tracked systems with higher Acceptance angles are designed to diffuse light or stray light to use. However, then decreases the concentration ratio and thus the utilization of direct radiation. This increases the relative overhead for tracking and for fixation.

Based on the fact that for small to medium-sized photovoltaic systems, especially in cloudy climates, the problem is that static concentrators reach too low concentration ratios, but tracking concentrators require a very high cost for tracking and fixation, is in the document DE 202 20 390 U1 proposed a semistatic photovoltaic concentrator, wherein the base member is a static, fixed mirror, whereas the absorber is movable with the solar cells parallel to the focal plane, whereby the focus on the absorber surface is achieved.

From the publication WO 89/05520 A1 an arrangement is known in which in a solar cell module a plurality of double-acting solar cells are provided, which are arranged above an array of a plurality of mutually parallel trough-shaped and semi-circular in cross-section mirrors; These mirrors redirect the part of the solar radiation incident on the underside of the solar cells next to the solar cells.

In the publication EP 0 059 464 A1 discloses a solar concentrator with a concave mirror concentrating the solar radiation on an absorber surface located between the mirror and the sun. The mirror is formed by a solid block of transparent material whose bottom is convexly curved and mirrored. In or on the top of the block, the absorber surface is arranged.

From the publication DE 195 08 071 A1 an arrangement is known in which in a solar cell according to the principle of thermovoltaics by the concentration of the sun's rays in the focal point or in the focal line of a specular cavity a higher energy yield than in a flat arrangement of the cells is achieved.

Other concentrator systems of the prior art are in the documents US 4,115,149 . US 4,191,164 . US 4,388,481 . US 5 062 899 . US 5,344,496 . WO 83/01292 A1 . WO 96/24014 A1 and WO 2004/109195 A2 disclosed.

The The concentrator systems discussed above is their efficiency loss at temperature increase during operation as well as the increase in resistance the solar cells in Teilabschattung together. The resistance increases by heat and / or by Teilabschattung draw one Reduction of electricity generation, because the solar elements are connected in series.

In summary can be found that the known concentrator systems are mechanically complex and require a high level of maintenance, whereas the planar systems available today are too expensive due to the high silicon cost.

Besides There are also systems made of polysilicon photovoltaic modules and / or are built from thick film photovoltaic modules. Such a Although construction is cheaper than a structure made of silicon photovoltaic modules, However, it regularly has a lower efficiency.

presentation of the present invention: object, solution, advantages from the disadvantages and shortcomings set out above, as well as is in appreciation of the outlined prior art The present invention is based on the object, a device of the aforementioned type so that a significant Cost reduction by using a concentrator system without moving Parts is achievable.

These The object is achieved by a device with the specified in claim 1 Characteristics solved. Advantageous embodiments and expedient developments The present invention is defined in the subclaims characterized.

The The present invention is basically based on utilization the defocusing of light radiation; this means at concave, especially spherical or parabolic domed, mirrors the arrangement of the photovoltaic Absorbers or solar cells below the focal point.

at Spherical mirrors this effect by the Kaustik supported in a very substantial way. The shape of a Parabolic mirror goes well at small opening angles approximated a spherical mirror shape. A parabolic mirror Although, in the true sense, no caustic, but arises also a burning surface when the object to be illuminated, So the solar cell is mounted below the focal point.

There the photovoltaic absorber means with respect to the mirror body Static mounted according to the invention is for the photovoltaic concentrator device according to the invention no mechanically-technologically complex manufacturing process required; Rather, the mechanical effort for the production, in particular for mechanical suspension, of the individual Modules comparable to or less than the mechanical effort for the production of planar systems available today.

As a result the use of the caustic and / or the fuel surface at least a readily available spherical or parabolic mirror surface, the present invention in a preferred development, neither complicated lens systems nor ground surfaces. This will be a mechanical stable modular construction without moving parts, so that a maintenance-free of the entire system is given.

According to one advantageous development of the present invention is achieved by a trough-shaped embodiment of the spherical or parabolic mirror surface a significant reduction achieved the shading. Here, the active side of the solar cells be facing with advantage the mirror surface, ie in the Be directed inside of the mirror.

As a result, is a direct shadowing within the invention Photovoltaic concentrator device not possible, so that the efficiency of the arrangement according to the present Invention can be increased.

by virtue of the preferably planar surface of the concentrator system According to the present invention, the mirror firmly on a building, preferably on the roof of a building Building, to be mounted. Due to the static mounting can the concentrator system according to the present Invention even replace a part of the roof, which in turn one represents significant cost advantage.

There the achievable performance of solar cells with increasing temperature decreases, it is expedient in the concentrator device according to the present invention for to ensure sufficient cooling of the absorber, for Example by means of at least one integrated in the optical body Heat dissipation system through which not only one Significant increase in the efficiency of the photovoltaic process or process can be achieved, but also heat energy for other use, for example for heating or heating purposes, can be provided.

For this can be at least one cooling system, for example at least a heat sink integrated in the optical system, and / or at least one active cooling is provided, in which the photovoltaic absorber by a flowing over Coolant is cooled. As already mentioned above implied, the active cooling brings the same time Advantage with itself that the received warmth for example for Heating or heating purposes can be used in addition.

All in all the present invention is characterized by a concentrator effect in a body or hollow body of optically transparent Material, which is a mechanically simple to produce and easily assembled system without mechanical Tracking is.

The present photovoltaic concentrator device has a focus on a focal plane and / or below a focal plane Focal plane or surface, wherein at least in the case of use a spherical mirroring of the optical body In addition, the effect of Kaustik comes into play.

through The present invention is a multiplication of the radiation density and thus minimizing losses in the photovoltaic absorber, as opposed to a cost reduction of the photovoltaic modules conventional systems by more than a factor of two.

The The present invention further relates to a photovoltaic field, a photovoltaic panel or a photovoltaic panel comprising several Devices according to the above Art, the modular to the field, to the panel or to the plate composed can be and expediently one have common optically transparent cover.

The The present invention finally relates to the use at least one device according to the above specified type and / or at least one photovoltaic array, at least a photovoltaic panel or at least one photovoltaic panel according to the type of concentration set forth above of incident light, in particular of sunlight, on at least a photovoltaic absorber, in particular at least one Solar cell, for example on at least one solar panel or on at least one solar cell latch.

Brief description of the drawings

As already discussed above, there are various possibilities for embodying and developing the teaching of the present invention in an advantageous manner. For this purpose, reference is made on the one hand to the claims subordinate to claim 1, on the other hand further embodiments, features and advantages of the present invention will be described below with reference to 1A to 5B illustrated embodiments explained in more detail.

It shows:

1A a schematic cross-sectional view of a component of an embodiment of a device according to the present invention;

1B a schematic cross-sectional view of a first embodiment of a device according to the present invention;

2A a schematic cross-sectional view of a component of an embodiment of a device according to the present invention;

2 B a schematic cross-sectional view of a second embodiment of a device according to the present invention;

2C a schematic cross-sectional view of a third embodiment of an apparatus according to the present invention;

2D a schematic cross-sectional view of a fourth embodiment of a device according to the present invention;

3A in a schematic cross-sectional view of a part of the device 1A and 1B ;

3B in a schematic cross-sectional view of the device 3A at central incidence of light;

4A in a schematic cross-sectional view of the device 3A at oblique incidence of light on the in 4A left area of the device;

4B in a schematic cross-sectional view of the device

4A at oblique incidence of light on the in 4B right area of the device;

5A in a schematic cross-sectional view of the basis of calculation for the device 5B ; and

5B in a schematic cross-sectional view of a third embodiment of an apparatus according to the present invention.

Same or similar embodiments, elements or features are in 1A to 5B provided with identical reference numerals.

Best way to execute of the present invention

In order to avoid superfluous repetitions, the following explanations concerning the embodiments, features and advantages of the present invention (unless stated otherwise) refer to all in 1A to 5B illustrated exemplary embodiments of devices 100 . 100 ' . 100 '' according to the present invention.

As 1A is removable, points the photovoltaic concentrator 100 . 100 ' . 100 '' a spherical or parabolic concave mirror 10 For example, from polished aluminum surface or from mirrored polystyrene, such as mirrored Polysterolplatten on, wherein the cavity of this mirror coating 10 may be filled with a medium such as a gas, for example with air, or with a transparent liquid, for example with water, or with an optically transparent material.

The in relation to the mirror body 10 statically mounted (standard commercial) solar cells 20 are located below the focal point of the mirror 10 in his caused by the Kaustik Brennfläche. In 1B is one of the possible arrangements of the photovoltaic absorber means, that is the solar cells 20 in the focal plane or surface of the mirror 10 shown.

• – insbesondere beliebig zur Brennebene oder Brennfläche des Spiegel körpers 10 gewinkelte und/oder
• – insbesondere beliebig zueinander gewinkelte Anordnung der photovoltaischen Absorbermittel 20 ist möglich (vgl. Ausführungsbeispiel gemäß 2D).

In principle, the photovoltaic absorber agent 20 essentially parallel (cf. 2 B ) or substantially perpendicular (cf. 2C ) to the focal plane or focal surface of the mirror body 10 be arranged. Also any,

• - In particular arbitrary to the focal plane or focal surface of the mirror body 10 angled and / or
• - In particular arbitrarily mutually angled arrangement of the photovoltaic absorber means 20 is possible (cf. 2D ).

In 1B the dashed line forms the so-called envelope (= envelope or envelope) of the caustic, where the envelope is understood as the curve that touches each curve of the family of curves in a single point. The focal surface is the extension of the dot-dash line.

The representation in 2A is removable, that the concentrator system 100 . 100 ' . 100 '' a cover formed for the purpose of translucence or optical transparency, for example, of (acrylic) glass 40 in the form of a cover plate, with the concave mirror 10 screwed and, for example, may have an optical refractive index n of about 1.5 or higher.

To better exploit diffused and / or oblique incident light, the planar cover 40 (see. 2A . 5B ) be provided with at least one thin coating, in particular with at least one thin film and / or with at least one thin layer of different production methods for light deflection. This results in an equivalent or comparable mode of action as in the case of refraction effects on optically different dense media.

• – an der Oberseite und/oder an der Unterseite der Abdeckung 40 oder
• – an der Oberseite eines massiven, optisch transparenten Körpers 50 angeordnet sein.

By this optional technical measure, the angular range of the obliquely incident light can be increased. The thin films and / or thin layers can

• - at the top and / or bottom of the cover 40 or
• - at the top of a massive, optically transparent body 50 be arranged.

To the efficiency of photovoltaic or solar cells 20 To raise is a hollow, with gas, to Example with air, flowed through or by liquid, for example, water, heat sink passed through 30 provided on the one exemplary dimensioning of fifteen millimeters having solar cells 20 are mounted (see. 2 B ).

Commercially are solar cells as plates in the format of about 150 millimeters up about 150 millimeters available; also solar cell bars with a dimension of about 15 millimeters to about 150 millimeters are commercially available and in the present invention used.

This cooling system, which is operated with gas, for example with air, and / or with liquid, for example with water, is basically optional, because at 2 B Although achievable concentrator factor can be used with a cooling housing, but also without liquid.

Two typical beam paths of the reflected radiation are in 3B as in 4A . 4B shown:

3A illustrates the principal ray path with substantially perpendicularly incident sunlight, whereas 4A and 4B show the principal ray path at an angle of incidence of the accepted solar radiation of about twenty degrees.

As 3A such as 4A . 4B Removable, the light rays in the focal plane of the spherical or parabolic mirror 10 concentrated and hit the arranged in the focal plane or below the focal plane absorber or solar cells 20 To a large Acceptance angle and a uniform illumination of the absorber surface 20 to ensure.

This arrangement in the photovoltaic concentrator 100 . 100 ' . 100 '' allows the solar cells 20 even with not perpendicular, but obliquely incident light without tracking the concentrator 100 . 100 ' . 100 '' illuminate. Furthermore, the caustic effect also causes scattered light and / or diffuse light a concentration of light in the focal surface and thus an optimal photovoltaic behavior not only in direct or oblique incidence of light, but also in diffused light and / or in scattered light. It should be remembered that obliquely incident light and diffused light are closest to northern European light conditions.

As with the device 100 . 100 ' . 100 '' According to the present invention concentration ratios between about the factor 2 and about the factor 10 are readily feasible (the actual concentration factor depends inter alia on the arrangement of the solar cells 20 in the burning surface), the silicon cost in the present invention is reduced by this factor over planar modules, thereby causing a significant cost reduction. In the embodiment according to 2 B a ratio of about 1: 3 is reproduced.

In 5B is the cross section of a photovoltaic concentrator module 100 represented according to the present invention. This module-shaped device 100 has a concave trough-shaped or trough-shaped, in cross-section spherical or parabolic curved mirror 10 as well as a cover plate 40 on, at the mirror 10 facing bottom underside of the rectangular cross-section heat sink 30 is attached, in its lower part, in turn, the solar cells 20 are arranged laterally bar-shaped.

The cooling element arranged below the focal point, for example 30 may be formed of aluminum and have an exemplary dimension of fifteen millimeters to twenty millimeters to two millimeters.

Such, based 5B illustrated arrangement 100 is mechanically simple and inexpensive to implement, requires no tracking and has a closed, flat surface in the form of the cover plate 40 , as is not uncommon in conventional planar systems.

Because of the effect of the mirror 10 and the associated caustics of the entire concentrator body 50 it is clear in its interior, that is 1A to 5B also illustrated the system essentially independently of the problem of partial shading, which adversely affects the operation of conventional planar systems.

A concentrator array or panel in accordance with the present invention may be constructed in a variety of ways 5B shown modular photovoltaic devices 100 have under a closed surface.

Of the Modular construction of the present invention makes it possible not only, the carrier body directly in a carrier frame but also allows the use of solar cells other materials than silicon. This distinguishes the present Photovoltaic concentrator very much of conventional concentrator setups and is also a prerequisite for a "service friendliness" of System.

A built-up photovoltaic array or photovoltaic panel has an area of about one square meter and may, for example, comprise twenty individual modules, each of which has an exemplary dimension of about one hundred millimeters to about five hundred millimeters. An equivalent arrangement can also be constructed with parabolic mirrors.

by virtue of its planar surface can be such a photovoltaic field or panel to be mounted firmly on a building, for Example to be integrated into the roof of a building.

100

Device for concentrating incident light, in particular sunlight (= embodiment according to 1B . 2 B . 5B )

100 '

Device for concentrating incident light, in particular sunlight (= embodiment according to 2C )

100 ''

Device for concentrating incident light, in particular sunlight (= embodiment according to 2D )

10

concave mirror or mirrors, in particular mirror bodies or mirroring

20

photovoltaic Absorber, in particular photovoltaic element or solar cell, for Example solar cell plate or solar cell latch

30

cooling device or coolant

40

Cover, in particular cover plate or cover plate

50

hollow body or body

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 20220390 U1 [0001, 0013]
• WO 89/05520 A1 [0014]
• EP 0059464 A1 [0015]
• - DE 19508071 A1 [0016]
• US 4115149 [0017]
• US 4191164 [0017]
• US 4388481 [0017]
• - US 5062899 [0017]
• - US 5344496 [0017]
• WO 83/01292 A1 [0017]
• WO 96/24014 A1 [0017]
• WO 2004/109195 A2 [0017]

Claims (12)

For concentrating incident light, in particular sunlight, provided device ( 100 ; 100 '; 100 '' ), comprising at least one statically mounted channel or trough-shaped mirror body ( 10 ), by means of which the incident light on at least one photovoltaic absorber ( 20 ), in particular to at least one solar cell, for example to at least one solar cell plate or at least one solar cell latch, is deflectable, characterized in that the photovoltaic absorber means ( 20 ) with respect to the mirror body ( 10 ) is statically mounted. Device according to claim 1, characterized by at least one solid, optically transparent body ( 50 ) or - by at least one filled with gas, for example with air, or with liquid, for example with water, hollow body. Device according to claim 1 or 2, characterized in that the mirror body ( 10 ) - is at least approximately spherical or parabolic in cross section and / or - in the body or in the hollow body ( 50 ) is integrated. Device according to at least one of claims 1 to 3, characterized in that the photovoltaic absorber means ( 20 ) in or below the focal plane or focal plane of the mirror body (in particular caused by the caustic) ( 10 ) is arranged. Device according to at least one of claims 1 to 4, characterized by at least one, in particular in the body or in the hollow body ( 50 ) integrated, cooling device ( 30 ), for example made of aluminum. Device according to claim 5, characterized in that the photovoltaic absorber means ( 20 ) at the cooling device ( 30 ), in particular - substantially parallel or - substantially perpendicular or - at least at an arbitrary angle to the focal plane or focal plane of the mirror body ( 10 ) is arranged. Device according to at least one of claims 1 to 6, characterized by at least one mirror body ( 10 ) including the photovoltaic absorber agent ( 20 ) covering, optically transparent cover ( 40 ), in particular cover plate, for example made of acrylic or glass. Device according to claim 7, characterized in that the cover ( 40 ) is provided with at least one light-deflecting coating, in particular with at least one light-deflecting film and / or with at least one light-deflecting layer. Apparatus according to claim 8, characterized in that the light-deflecting coating - at the photovoltaic absorber means ( 20 ) facing side of the cover ( 40 ) and / or at the photovoltaic absorber means ( 20 ) facing away from the cover ( 40 ) or - at the top of the solid, optically transparent body ( 50 ) is arranged. Device according to claim 5 or 6 and according to at least one of claims 7 to 9, characterized in that the cooling device ( 30 ) at the mirror body ( 10 ) facing the underside of the cover ( 40 ) is arranged. Photovoltaic panel or photovoltaic panel, comprising a plurality of devices ( 100 ; 100 '; 100 '' ) according to at least one of claims 1 to 10. Use of at least one device ( 100 ; 100 '; 100 '' ) according to at least one of claims 1 to 10 and / or at least one photovoltaic panel or photovoltaic panel according to claim 11 for concentrating incident light, in particular sunlight, on at least one photovoltaic absorber means ( 20 ), in particular on at least one solar cell, for example on at least one solar cell plate or on at least one solar cell latch.