WO2016169537A1 - Mirror for concentrating sunlight for a solar power installation, method for operating a solar power installation and solar power installation - Google Patents

Mirror for concentrating sunlight for a solar power installation, method for operating a solar power installation and solar power installation Download PDF

Info

Publication number
WO2016169537A1
WO2016169537A1 PCT/DE2015/000386 DE2015000386W WO2016169537A1 WO 2016169537 A1 WO2016169537 A1 WO 2016169537A1 DE 2015000386 W DE2015000386 W DE 2015000386W WO 2016169537 A1 WO2016169537 A1 WO 2016169537A1
Authority
WO
WIPO (PCT)
Prior art keywords
mirror
solar power
characterized
segments
power plant
Prior art date
Application number
PCT/DE2015/000386
Other languages
German (de)
French (fr)
Inventor
Jürgen KLEINWÄCHTER
Original Assignee
Kleinwächter Jürgen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DE102015005221 priority Critical
Priority to DE102015005221.7 priority
Application filed by Kleinwächter Jürgen filed Critical Kleinwächter Jürgen
Publication of WO2016169537A1 publication Critical patent/WO2016169537A1/en

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S23/82Arrangements for concentrating solar-rays for solar heat collectors with reflectors characterised by the material or the construction of the reflector
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S23/71Arrangements for concentrating solar-rays for solar heat collectors with reflectors with parabolic reflective surfaces
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S2023/83Other shapes
    • F24S2023/833Other shapes dish-shaped
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S2023/87Reflectors layout
    • F24S2023/874Reflectors formed by assemblies of adjacent similar reflective facets
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/40Solar thermal energy
    • Y02E10/42Dish collectors

Abstract

The invention relates to a mirror for concentrating sunlight for a solar power installation, a method for operating a solar power installation and a solar power installation. Parabolic mirrors are known in the prior art. An important application of parabolic mirrors is the concentration of sunlight for the utilisation of solar energy. By means of concentrating using large parabolic mirrors, high temperature can be reached in the focal points thereof. The energy made available in this way can be used to melt metals or to produce steam. Small technical applications, such as solar cookers, also often use parabolic mirrors for concentrating solar energy. The invention proposes various advantageous mechanical and geometric approaches.

Description

 SUNLIGHT BINDING MIRROR FOR A SOLAR POWER PLANT, METHOD FOR OPERATING A SOLAR POWER PLANT AND A SOLAR POWER PLANT

The invention relates to a mirror for sunlight bundling for a solar power plant, a method for operating a solar power plant and a solar power plant. Parabolic mirrors are known in the art. An important application of parabolic mirrors is the bundling of sunlight for the utilization of solar energy. By bundling with large parabolic mirrors, high temperatures can be reached at their focal point. The available energy can be used to melt metals or generate steam. Small-scale applications, such as the solar cooker, often use parabolic mirrors to bundle solar energy (source: https://de.wikipedia.org/wiki/parbolspiegel, retrieved on 13 July 2015).

The invention has for its object to provide the prior art an improvement or an alternative. According to a first aspect of the present invention, this object is achieved by a sunlight-gathering mirror for a solar power plant, comprising a plurality of strip-shaped segments for shaping a resulting solar light to a focus-reflecting surface, the segments having a tangential extension.

Conceptually, it should be explained: A mirror of the genus relevant here bundles parallel incident light rays, thus thus especially the sunlight, towards a focus.

Confirmation copy | Mirrors of the genus considered here are generally of large dimensions, for example with a diameter of over one meter, often even with a diameter of over two or more than three meters. Due to the size and the production simplification such mirrors are regularly divided into strip-shaped segments. The strip-shaped segments are connected to each other and thereby form the reflective surface.

According to the first aspect of the invention presented here, the segments have a tangential extension. In simple terms, this means that the strips will have the shape of a section of an imaginary rotationally symmetrical body, the strips being taken from this imaginary body along the circumference.

An ideal mirror for bundling sunlight is a paraboloid of revolution. A rotational paraboloid is rotationally symmetric about a central axis. A strip has an extent along a circumference about this axis which is longer than the extension of the strip in the direction of the axis.

In the prior art it is well known to assemble strip-shaped segments in the axial direction of the rotary body. Because this type of division of the rotating body causes all the strips and thus all segments have an identi- see shape, which simplifies the manufacturing process at first glance.

The inventor has, however, now recognized that the overhead when using strips in the tangential direction is manageable. Above all, it is also possible to accept deviations from the ideal paraboloidal form of revolution, with the resulting losses being at the limit of the measurable range. The mirror can be constructed in a still good approximation to the ideal with identically shaped segments also over different heights along the axis of rotation.

Preferred, however, is an embodiment in which the mirror has differently shaped segments. The particularly preferred embodiment provides that the mirror at a height - with respect to the axis of rotation - identically shaped, laterally adjacent segments, however, has over the height differently shaped segments.

On the exit side of the mirror or the paraboloid or its approach, narrower shaped segments are preferably provided as vertex-side. The smaller the segments extend in the axial direction, the lower are the errors if the contour of the individual segment does not exactly correspond to a paraboloid of revolution, but differs therefrom.

A particular embodiment of the inventor provides that in the longitudinal, thus projecting to the axis boundary edges of each segment just no parabolic pieces are simulated as a geometry, but simply circular arc pieces. These can be manufactured and maintained considerably less expensive. However, as the mirror moves away from the vertex, the more significant it becomes that the error caused by the deliberately "wrong" geometry is minimized, as can be achieved by the shorter - in axial direction - segment sizes Segments with a tangential extension put together a parabolic mirror.

However, according to the present state of the art, the inventor considers it more skilful if a segment has edges that deviate from a paraboloid of revolution, especially edges with arc-shaped edges. A rotational paraboloid shape is expensive to manufacture, which has a negative effect on the costs. On the other hand, it is significantly cheaper and even in technically less developed environments possible to produce circular arc segment-shaped edges. The invention has recognized that the deviations from the paraboloidal parallicular shape are less than would be justified by the overhead of producing the paraboloidal paralloid form.

Thus, at least one segment should have different edges than the paraboloid of revolution shape.

In general, it should be expressly pointed out that in the context of the present patent application indefinite articles and numbers such as "a", "two" etc. should be understood as "at least" information, ie as "at least one" at least two ... " etc. unless express or implied from the context or obvious to one skilled in the art that it may or may not be meant to mean "just one ...", "two ..." and so on.

The proposed mirror preferably has recesses relative to a complete rotational body, in particular at least fifty percent of the surface of the rotary body.

For bundling the sunlight for a solar power plant usually only a small portion of the total surface is necessary, especially if the mirror has an intelligent tracking. According to a second aspect of the present invention, there is provided by the present invention a sunlight-concentrating mirror for a solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus-reflecting surface, which mirror may in particular also correspond to the first aspect of the invention the mirror is characterized records that the segments have a shaping pneumatic positive or negative pressure relative to an ambient pressure.

With such a construction, it is possible to shape the segments via the positive or negative pressure. This also implies that the segments are in any case designed to be airtight on the reflective surface or are at least designed to be dense for another fluid, be it a gas or a liquid. By introducing or discharging the fluid, the shape can be adjusted. For example, the construction may be such that, within a certain range around an ideal internal pressure to be set, the surface still assumes only very little deformation from the ideal shape, and thus does not unduly diminish the efficiency of the solar power plant. This also contributes to the fact that the invention can be used profitably in less well equipped areas.

A particularly simple case is inflation with air or aspiration of air. There is no need to use a special gas or liquid, and the segments can be particularly light. Ideally, the segments can easily collapse, be it for transport or maintenance or mining purposes. Several segments can be connected to each other via a fluid guide. With such a construction, a plurality of segments, especially all segments, of a mirror may be shaped via the simple injection or deflation of air or other fluid. A segment can have a transparent film and a reflective film, wherein the transparent film and the reflective film are connected to one another in airtight manner to form a bag, in particular are welded together.

Such a construction allows the transparent foil to be preferably assigned to the incident solar radiation so that the rays of the sun strike the reflecting foil through the transparent foil. The reflecting surface is thus within the bag, thus within the example inflated with overpressure pillow-like bag in the operation of the mirror, so that the reflective film is optimally protected against, for example, dust pollution.

If a segment identifies a support frame, then the mechanical loads on the support frame can be removed, and very lightweight constructions for the specular surface, such as foils, can be used.

A segment may comprise an inflatable tensioning element, in particular a hose, especially with different inner pressure chambers along a circumference.

In such a way, the tensioning element can be inflated, for example with air or another fluid, be it a gas or a liquid; The film-like reflecting surface is set in tension by the tensioning element and thereby assumes exactly the orientation to which the mirror is designed.

According to a third aspect of the present invention, the stated object solves a sunlight concentrating mirror for a solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular a mirror according to one or two of the aforementioned aspects of the invention the mirror is characterized in that the segments are designed as a mirror pad, having a fluoropolymer film.

140 In prototype experiments by the inventor, fluoropolymer films have been found to be ideal for the pillow-like mirrors.

Particularly suitable is ethylene-tetrafluoroethylene (ETFE).

Also have for a transparent film thicknesses between 50 μιη and 200 μπι found to be ideal, in particular between about 100 μπι and 150 μιη. For the reflecting surface, mirror films with an aluminum layer have proven to be ideal, in particular with a sputtered aluminum reflector.

According to a fourth aspect of the present invention by the stated object, a mirror for sunlight bundling for a solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular also formed according to one of the three preceding aspects of the invention, wherein the mirror characterized in that the segments have a mirror foil, wherein the mirror foil on its preferably non-reflective back has a mechanically reinforcing grid structure.

A reinforcing "grid structure" is to be understood as meaning that there are stripe or suture-like thickenings in the thickness of the film which may be interconnected.

Preferably, the lattice structure is rhombic.

According to a fifth aspect of the present invention by the stated object a method for operating a solar power plant with a mirror for sunlight bundling for the solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular for operating the solar power plant with a A mirror according to any of the aspects of the invention discussed above with regard to the mirror, the method being characterized by the gas depleting or gas filling segments for reducing the bundling effect in an emergency mode.

According to a sixth aspect of the present invention by the stated object a method for operating a solar power plant with a mirror for sunlight bundling for the solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular for operating the solar power plant with a mirror such as to one of the first four pect of the invention and / or described in accordance with a method according to the fifth present aspect of the invention, wherein the method is characterized in that the segments are vibrated by means of fluctuating compressed air to clean their surface. The amplitude which the segments assume by means of fluctuating compressed air into the surface is not primarily decisive. Rather, the vibration can be used to shake off snow or dust, for example.

According to a seventh aspect of the present invention, the stated object solves a solar power plant with a mirror for sunlight bundling, wherein the mirror on a spatial framework-like mirror carrier incident solar light is fixed reflective to a focus and the mirror support is equipped with a preferably motorized daytime tracking, the Tagesnachführung is set up to rotate the mirror support about an axis of rotation and thereby track the changing direction of incidence of the sun, wherein the solar power system characterized in that the axis of rotation is aligned with a structure of the solar power plant in the northern hemisphere to the North Star and the Tagesnachführung to is set up to rotate the mirror in an engine with an angular velocity of 15 ° / min about the axis of rotation, while leaving the focus and a receiver arranged in focus stationary. In addition, a seasonal tracking is preferably provided, which is set up here to tilt the mirror about at least 15 °, preferably at least 20 °, in particular about 23.5 ° about a tilt axis, wherein the tilt axis extends horizontally through the center of the turntable.

Such a solar power system is particularly advantageous if the mirror support is used to effect the Nachführmechanik, while the mirror support can carry the lightest possible mirror, such as a pillow-like, inflated mirror. Above all, mirrors come in accordance with the above-mentioned four aspects of the invention, and / or mirrors, in which the methods according to the fifth or sixth aspect of the invention are used. According to an eighth aspect of the present invention, the stated object solves a solar power plant with a mirror to sunlight bundling, wherein the mirror is mounted on a spatial framework-like mirror carrier incident solar light reflective to a focus and the mirror support is aligned with a preferred motorized daytime tracking, the Tagesnachführung set up is to rotate the mirror support about an axis of rotation and thereby track the changing direction of incidence of the sun, wherein the solar power system is characterized in that a control is provided having a focus sensor, a controller and a deformation motor, the controller with the focus sensor data-connected is and is operatively connected to the deformation motor, wherein the controller is adapted to, during operation of the solar power plant, the focus of the collimated sunlight by means of a deformation of at least one segment of the mirror a n to hold a target value.

It should be expressly understood that the "target value" may also have a tolerance range, wherein the tolerance range is preferably specified in the controller.

The "deformation motor" must be set up to regulate at least one segment, preferably all segments, of the mirror, whether jointly or individually controllable, to the designated focus, for example, it is conceivable that air slowly escapes from a cushion-like mirror segment For example, it would then be able to blow in further air into the segment via a pump and / or to adjust the segment at its edges one or more than one axis, ideally by all six spatial degrees of freedom. In this case, the segments can each be coupled adjacent to one another at their edges, but they can also be individually freely adjustable, that is, they can be arranged only unconnected adjacent to one another.

The invention will be explained in more detail below with reference to further explanations of the background theory and with reference to embodiments with reference to the drawings.

Show there

FIG. 1 schematically shows a paraboloid of revolution with a focus F, in which all light beams perpendicular to the entrance plane of the paraboloid unite,

FIG. 2 is a graph comparing the intercept factor with that of the ideal paraboloid over the diameter of the receiver aperture when the mirror is equidistant,

FIG. 3 shows in a three-dimensional graph the intercept profile of a fix-focus mirror constructed in six circle-sun sections in equinox position, FIG. 4 shows schematically in a section a transparent, flat foil and a reflective, flat foil,

FIG. 5 shows, in a spatial view, a section of a reflective film with a reinforcing grid structure,

FIG. 6 shows a partial section of a segment in a three-dimensional view, FIG. 7 schematically shows the cross-section already illustrated in FIG. 4 through a mirror segment with a mounting unit;

8 is a schematic sectional view of a vacuum level, FIG.

FIG. 9 shows a schematic view in a three-dimensional view of a lightweight membrane paraboloid with six segments,

FIG. 10 shows in a diagram the realizable intercept factors with the mirror geometry illustrated in FIG. 9,

FIG. 11 schematically illustrates, in a spatial view, an infinitesimally small area element of a film which is deformed under a pressure p, in order to explain the mechanical background;

FIG. 12 shows schematically in a spatial view a rotational paraboloid with surface elements as well as to illustrate the geometric background

FIG. 13 schematically shows the geometry of the tracking of the fixed-focus mirror presented here.

The present embodiments describe the structure, the mode of operation and the essential fields of application of an extremely light eccentric ("fixed-focus") quasi-parabolic sunlight concentrator, the reflectors consisting of arrangements of transparent and reflective structures limited by special profiles Polymer membranes whose surface shape is formed by controlled air overpressure or air underpressure.

The essential, underlying ideas of the inventors are: a) Extremely low basis weight of the respective mirrors - therefore low energy requirement for their production ("gray energy") - fast energetic amortization b) high surface quality (among other things low roughness) of the tensioned, mirrored membrane c) parabolic similar shape of the membrane in her elastic expansion range by targeted exposure to gas (air) over- or under-pressure.

In 1913, the Dutch physicist H. Hencky in his study "On the stress state of circular plates with vanishing flexural rigidity" formulated the formula for the description of the equilibrium form, which thin films, which are clamped in a circular and rigid manner in their periphery, are pressurized.

Figure imgf000013_0001

Where w r represents the deflection of a membrane in the z-axis. Differentiated, this equation yields:

Figure imgf000013_0002

For a parabola, the slope of the surface as a function of the radius is characterized by a linear function. The second term in equation (2). however, is a 3rd order term that shows that the "Hencky" membrane is steeper in the periphery than a parabola (similar to the spherical aberration of a spherical mirror).

H. Kleinwächter calculated the stress states (longitudinal and transverse stresses) in such an air-pressure deformed membrane, and recognized that an originally pla- ne membrane must be biased in an anisotropic manner in a systematic manner, so that it assumes an exactly parabolic shape after defined pressurization. For this purpose, an infinitesimally small surface element of a film is considered, which is deformed under the pressure p. Bending stresses in the film should be assumed to be negligible, cf. FIG. 11

For the equilibrium case, the balance of forces between the force F P caused by the pressure and the forces CTi and F a2 caused by the restraint tensions can be established.

The sizes can be used with reference to FIG. 1, wherein the voltage components opposite the pressure for small angles behave as shown in FIG. 1 b) of FIG. 11. p · p da x · p 2 d 2 = σ ά χ s p 2 da 2 + a da 2 · s p x d x

(4) Conversion of equation (4) results

Figure imgf000014_0001

For this purpose, it is assumed that the film deformed under atmospheric pressure takes the form of a z-axis rotating paraboloid with the focal length f. zW ~ 4f * (6)

By calculating the principal curvatures, due to the rotational symmetry, the two radii of curvature of the paraboloid p \ (with respect to the latitudinal circles) and pi (in the meridian direction) are determined as a function of only the quantity x (cf. FIG. 1).

Figure imgf000015_0001
Figure imgf000015_0002

The quotient of both radii of curvature to each other then gives

Figure imgf000015_0003

The stretching of the film in one direction in the surface element under consideration is added up by two components. The first component is the strain caused by the stress acting in this direction. The second component is caused by the transverse contraction resulting from the stress acting in the orthogonal direction.

1 v 1 v

ε 1 = σ 1 - - σ 2 - or ε 2 = σ 2 - - σ 1 -

(1

E denotes the modulus of elasticity of the film material and v its Poisson number, which describes the transverse contraction behavior in the material when stretched. The equation system of (10) resolved by σ \ and σι yields Ε (ε 1 + νε 2 )

 σ =

1 - ν 2 (Π) resp.

Ε (ε 2 + νε) (12). σ 2 =

1 - ν 2

The formulas (11) and (12) can now be used in (5) and obtained

Figure imgf000016_0001

Summing up for the preceding consideration, it can be said that a flat film under pressure takes on a paraboloidal shape if and only if the film stresses in the described anisotropy are realized.

From these considerations emerged the concept of the fixed-focus concentrator. An array of n identical film segment mirrors (typically trapezoidal) rotate about the polar axis at a continuous 15 ° / h and reflect sunlight over the small entrance aperture (focal plane of the mirror) into a cavity receiver. The seasonal adjustment (± 23.5 °) is made via a second axis passing through the aperture plane (see Figure 1).

Various prototypes were realized with aperture areas of 2 m 2 to 20 m 2 . Mean sunlight concentrations of well over 1,000 suns (mean concentration c> 1,000) were reached. This opens up the possibility of using cavity receivers and the effective achievement of process temperatures up to approx. 2000 ° C. The main advantage of the fix-focus concept over classic paraboloidal mirrors (where the receiver has to follow the sun tracking motion) is the mechanical decoupling of heavy, stationary receivers with and without storage. from the moving lightweight optics. Various areas of application were demonstrated with the prototypes:

Solar cooking around the clock using steel or sand as the storage medium

Operation of a thermochemical, reversible Mg - MgH 2 store for the base load operation of a Stirling engine ■ Themocatalytic receiver for splitting H2S into Hb and sulfur

Coupling the light into stationary light guides

metallurgy and ceramics

The conversion of eccentric paraboloid segments with anisotropic bias into a rational, economically feasible series production has not been successful for the following reasons:

1.) Complicated, time-consuming mechanical preload method

2.) Creep in the film - need for readjustment

3.) Since the preloads may only take place in the elastic region of the film extension, low preload forces lead to the wind sensitivity of the mirror segments with respect to deformation of the reflective membrane.

The inventors of the present application have set themselves the task of developing an eccentric lightweight parabolic mirror, which retains and improves the advantages of the described in the previous chapter fixed-focus mirror (fixed focus, low weight, mirror forming by gas (-air)) Pressure, but its inherent weaknesses (complicated anisotropic bias, deterioration of the image due to flow of the plastic, time-consuming and expensive production) avoid det.

For this purpose, two essential beyond the known prior art development and knowledge steps were necessary. First of all, the idea arose to extract the fixed-focus mirror not from long strips in the meridian direction but from long strips in the direction of rotation out of the paraboloid.

Fig. 1 is this fact again. In this case, (1) represents the original paraboloid of revolution with the focus F, in which all rays of light coinciding perpendicularly to the parabolic plane of the paraboloid join. Under (la) are three fixed-focus segments, in the meridian direction, as described in US Pat State of the art are already known, shown systematically.

The lateral profiles of these segments (2a) extending in the meridian direction must of course conform to the parabolic shape of the parent paraboloid, ie form parabola sections. On the other hand, the short upper and lower profiles (2b) delimiting the segments (1a) form circular sections. So that they deform parabolically under pressure, such prior art membrane mirrors, as described, must be selectively biased anisotropically due to the curvature that constantly changes in the meridian direction. If, however, the segments are formed in the direction of rotation according to the invention, as represented by three schematically represented segments (1b), the short sides (3b) will also close in good approximation (since they extend only for a short distance in the axial direction) arcs. The long sides of the boundary profiles (3a) form precise circular arcs anyway. Due to this boundary with circular arcs, with by definition constant radii of curvature, no anisotropic bias of the mirror membrane is necessary. The membrane cut to form a truncated cone only needs to remain homogeneous after being fixed to the frame. be tense.

Under controlled gas (air) pressurization, the individual segments (l b) form superimposed circular-segment segments whose foci overlap in F. With a sufficient degree of slenderness of the individual elements, the arrangement of an eccentric paraboloid according to the invention represents a very good approximation to the corresponding section of the ideal paraboloid, as shown in FIG.

FIG. 2 comparatively shows the intercept factor (relative size proportional to the irradiation power) of the arrangement according to the invention and the ideal paraboloid over the diameter of the receiver aperture in the case of the aquinox position of the mirror. The concentration ratios of the ideal fix-focus paraboloid are only marginally better. In the graphical representation of the intensity distribution, a deformation of the focal spot is barely recognizable. In the z-direction, the focal spot runs somewhat further due to the shape errors than in the y-direction. By optimizing the subdivision of the mirror surface (smaller segments at the top than at the bottom) and optimizing the alignment, the ideal paraboloid concentration could be further approximated.

FIG. 3 shows the intercept profile of a fix-focus mirror in equatorial position constructed from 6 circle-sun sections, according to the invention. The fact that the segments in the direction of rotation, as described, only need to be biased homogeneously, leads to the second innovation according erfindungsaspektgemäßen over the described prior art: the homogeneous pneumatic bias of the films.

This is illustrated in FIG. 4. In this case (4) is a transparent, flat film and (5) a reflective, flat film. Foils (4) and (5) are joined together at their edge (6) airtight.

The bag formed by (4) and (5) is made up as a matching truncated cone, which is then pulled over the frame structure (2 x 3a + 2 x 3b). the. Along the outer periphery of the frame runs an inflatable elastic hose or optionally an inelastic, flat ground plane tire (7).

If an overpressure pi is now applied inside the tube, it expands and exerts a defined tension on the foil. Here, the original bias of the film is not crucial, since the hose compensates this within certain limits over its extent and maintains the defined tension on the film. Temperature changes in the film are compensated by the hose in this way.

- h (Pi ~ P2)

° F - hR 2 - d F (14).

This situation becomes clear by establishing the equilibrium of forces between the tensile forces of the foils and the counteracting force on the inner frame (14). Here, OF represents the tension in the film, CIF the thickness of the film and HR the height of the inner frame. Pi represents the forming air pressure between the films (4) and (5), where pi »pi.

The tire (7) is held in position by the auxiliary profile (8).

In principle, it can run as a mono tube around the entire frame structure (whereby it runs in the corner regions 3a-3b in a fixed channel which prevents its bending) or consist of four individually inflatable, linear individual sections (2 x along 3a, 2 x along 3b).

The pressurized hose exerts a constant pressure on its inner wall. Now the tension in the membranes can also be applied anisotropically. The voltage anisotropy can then be controlled via the frame height HR. This anisotropy is maintained even with temperature changes in the film. Alternatively, the anisotropy can also be achieved according to the invention by replacing, instead of varying on the profile thickness of the tire along the membrane edge of n sections with different internal pressure arises.

The edge weld (6) is executed in its radii of curvature analogous to the curvature radii of the shaping profile (3a). Since the films (4) and (5) are preferably made of highly transparent and light-resistant fluoropolymer films, which are quite difficult to combine with conventional pressure heaters due to their high melting points with defined pressure, two methods are preferably used to solve this problem elegantly: Fusion by means of ultrasonic vibrations or by targeted laser beam injection. Both methods also allow a precise design of the required contour of the weld (6).

The choice of material of the mirror elements according to FIG. 4 is a clever option of the present invention. To ensure the main criteria, low weight, high precision and long life, according to the present state of knowledge of the inventors following material combinations are to be preferred:

Material of the mirror cushion

Fluoropolymer films, in particular ETFE in material thicknesses between 100 μιη and 150 μηι; Sunlight transmission of the transparent film (4)> 95%. Lifetime:> 30 years. Stain-resistant. Hail as a pneumatic pillow. Reflective foil preferably provided with puttied aluminum reflector: thus ultraviolet sunlight can be concentrated in focus, since the films are highly transparent even for the natural UV spectrum (300 - 400 nm). For this reason, the mirror technology of the invention is also very well suited for combination with photochemical and photocatalytic receivers (which as a rule benefit greatly from the fixed arrangement). Material of the mirror frame

For weight reasons, if metallic, aluminum profiles. In addition, non-metallic fiber composite materials are particularly well suited.

Material of the preload tire

Prefers ETFE hoses because of their lifetime under light and low coefficient of friction - thus easy lateral and vertical displacement, which facilitates the wrinkle-free bias of the reflector membranes.

The Vorspannpneu (6) compensated over a wide control range typically changes in the pressure in the pneumatic mirror due to ambient temperature changes and also temperature-induced elastic behavior of the films (4) and (5). Even a possible flow within the film can be corrected.

However, in order to exclude flow in principle, especially the reflective film (5) can be used erfindungsaspektgemäß as a flexible, lattice-reinforced composite. Figure 5 shows schematically such a composite. Here, (5) is a section of the specular film, (9) the visible on its underside lattice structure and (9a) is a typical pattern of this flexible lattice structure in rhombic form, which allows good biases in both the longitudinal and transverse directions. Such a film composite can-in particular according to the state of fluorine film technology-typically be implemented in the following manner: A thin grid of tensile fibers is positioned flat and then covered with a gel-like layer of "liquid fluorine film" so that no roughnesses of the grid penetrate. Finally, a composite of the fluorine side of the film (5) with the liquid film surface by gentle, flat surface realized pressure and the liquid film by evaporation of the solvent in the solid state.

In addition to avoiding flow when using this film variant, also the form of the mirror cushion can be chosen so large that even stronger exposure to wind does not significantly impair the optical precision of the elements. According to the invention, the biasing pnn (6) can also be used to achieve another important function: In concentrating solar paraboloids with high energy density in focus, there may be a need to "switch off" the energy supply by the radiation in a short time By a fast moving out of the mirror from the sun position or by folding a protective shield into the beam path, the former requires elaborate "high speed" in the mirror tracking and the second method must resort to problematic shields high heat load. In the case of the present invention, by rapidly depressurizing the biasing tang, the mirror geometry can be "defused" immediately.

If one works with fluctuating compressed air into the tire (6), a targeted vibration of the mirror pad surface can be achieved, whereby according to the invention dust, dirt and snow can be shaken off (supported by the low surface adhesion of the fluoropolymer membrane).

A light weight of the lightweight membrane segments (1-2 kg / m 2 ) is achieved by a structure similar to a model airplane wing. In Fig. 6 is a partial section of such a segment can be seen. In addition to the already described longitudinal and lateral profiles (3a, 3b), the auxiliary profile (8), the upper transparent (4) and the lower reflective film (5), and the barrel-shaped foil cushion (lb) here the cross support (3c) is located , It prevents the transverse contraction force, which occurs when the pad (1b) and the tire (6) not shown here from being deformed on the frame, from being unduly deformed. The segment shown schematically in Fig. 6 has the reasons described despite extreme lightweight construction and membrane construction a high optical quality. However, due to the deliberately chosen small dimensions of the profile frame (weight), it is relatively sensitive to torsion in the longitudinal direction. According to the invention, this torsional sensitivity is converted to a system advantage. Since the individual mirror segments are incorporated as an overall configuration in a lightweight torsion-stable lattice support structure, which serves as a mirror support, the ability of the segment adjustment is used when mounting on the mirror support.

In FIG. 7, the cross-section already explained by FIG. 4 is supplemented by a mirror segment by an assembly unit (8a) which is connected to the mirror-carrier space frame (10) by means of a length-adjustable strut (8b). In accordance with the invention, in this way several points of the mirror segment frame are connected to the space frame. By optical observation in the focal plane individual segments can be finely adjusted in this way. The mirror segment described so far acts as an overpressure mirror because a pneumatic overpressure is built up between the upper transparent film and the lower reflective film. This has the advantage that the reflector is protected from direct weather, but due to the two-time radiation passage through the film (4), a reflection loss of about 10% occurs. An optical aluminum layer has a reflectivity of approx. 90%, so that an optical efficiency of approx. 80% can be effectively expected.

From Fig. 8 shows that the described in Figure 4 overpressure mirror by adjusting the height of the profile (3a) can be realized in principle as a vacuum level, and thus with 90% optical efficiency. (3a) must be chosen so high that the reflective (5) and the transparent film (4) do not touch when in the space between (4) and (5) a focal length-dependent negative pressure is set. FIG. 9 schematically shows the structure of a six-segment eccentric lightweight membrane paraboloid according to the invention. The six mirrors are fixed in the manner discussed on the designed as a space frame mirror carrier. The axis of rotation of the parallactically mounted mirror passes through the center of the turntable (1 1) and points (on the northern hemisphere) to the Polarstern. This means that the angular velocity of the daytime tracking system is constantly 15 ° / min. Due to the high concentration of light which impinges on the focal plane in a relatively small solid angle range, the light is coupled through a pupil with the diameter of the focal spot into a highly effective cavity receiver (13). The seasonal Nahfuhrung (12) of the mirror in function of the sun altitude (± 23.5 °) (elevation) is accomplished via a second axis of rotation, which runs horizontally through the center of the turntable. Due to the lightweight construction of the mirror and the mirror carrier, the eccentric torques occurring as a function of the mirror position, as well as the adjustment of the elevation, are possible without complicated mechanical constructions.

With pneumatically shaped concentration mirrors surface qualities of approx. 3 mrad can be realized. FIG. 9b shows that with the mirror geometry shown in FIG. 9, intercept factors of almost 100% can be realized.

The main effect of the invention is to bring the great potential of the sun, especially for decentralized use in villages and settlements of the South to use. High-performance solar optics, which are used in the form of low-cost, lightweight and easy-to-assemble kits (assembly kits) due to the specific features of the invention, can make very significant contributions to local autonomy, quality of life and value creation.

A wide range of applications - from solar cooking around the clock, to water treatment in concentrated, natural UV light, to operation simple Stirling machines for power, power and cold are possible with it.

Claims

claims:
A sunlight-condensing mirror for a solar power plant, comprising a plurality of strip-shaped segments for shaping an incident solar light to a focus-reflecting surface, characterized in that the segments have a tangential extension.
2. Mirror according to claim 1, characterized in that it has differently shaped segments.
3. Mirror according to claim 2, characterized in that it has on the exit side of the parabolic mirror narrower segments than the crest side.
4. Mirror according to one of the preceding claims, characterized in that the mirror is formed as a parabolic mirror.
5. Mirror according to one of claims 1 to 3, characterized in that a segment of a Rotationsparaboloidform deviating edges, in particular circular arc segment-shaped edges.
6. Mirror according to one of the preceding claims, characterized in that it has recesses relative to a complete body of revolution, in particular at least 50% of the surface of the body of revolution.
7. Sunlight bundling mirror for a solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular a mirror according to any one of the preceding claims, characterized in that the segments have a shaping pneumatic overpressure or negative pressure relative to an ambient pressure.
8. A mirror according to claim 7, characterized in that a segment comprises a transparent film and a reflective film, wherein the transparent film and the reflective film are airtight to each other connected to a bag, in particular welded together.
9. Mirror according to claim 7 or 8, characterized in that a segment has a support frame.
10. Mirror according to one of claims 7 to 9, characterized in that a segment comprises an inflatable tensioning element, in particular a hose, especially with along a circumference different internal pressure chambers.
11. mirror for sunlight bundling for a solar power plant, comprising a plurality of segments for forming an incident solar light to a focus reflecting surface, in particular mirror according to one of the preceding claims, characterized in that the segments are designed as a mirror pad, having a fluoropolymer film.
12. Mirror according to claim 1 1, characterized in that a mirror pad ethylene-tetrafluoroethylene (ETFE).
13. Mirror according to claim 1 1 or 12, characterized in that a transparent film with a thickness between 50 μηι and 200 μπι is used, in particular between 100 μπι and 150 μιη.
14. Mirror according to one of claims 11 to 13, characterized in that a mirror foil is provided with an aluminum layer, in particular with a sputtered aluminum reflector.
15. A mirror for sunlight bundling for a solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular mirror according to one of the preceding claims, characterized in that the segments have a mirror foil, wherein the mirror foil on its non-reflective Rear has a mechanically reinforcing grid structure.
16. A mirror according to claim 15, characterized in that the grid structure is rhombic.
17. A method for operating a solar power plant with a mirror for sunlight bundling for the solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular for operating the solar power plant with a mirror according to one of the preceding claims, characterized in that the segments to reduce the bundle effect in an emergency mode gas-evacuated or gas filled.
18. A method for operating a solar power plant with a mirror for sunlight bundling for the solar power plant, comprising a plurality of segments for shaping an incident solar light to a focus reflecting surface, in particular for operating the solar power plant with a mirror according to one of the preceding claims, characterized in that the Segments are vibrated by means of fluctuating compressed air in order to clean their surface.
19. Solar power plant with a mirror for concentrating sunlight, wherein the mirror is mounted on a spatial framework-like mirror carrier incident solar light reflecting to a focus and the mirror carrier is equipped with a preferred motorized Tagesnachführung, the Tagesnachführung is adapted to rotate the mirror support about a rotation axis and thereby tracking the changing direction of incidence of the sun, characterized in that the axis of rotation is aligned in a structure of the solar power plant in the northern hemisphere to the North Star and the Tagesnachführung is set to the mirror when motorized at an angular velocity of 15 ° / min about the axis of rotation to rotate while leaving the focus and a receiver arranged in focus stationary.
20. Solar power plant according to claim 20, characterized in that a seasonal tracking is provided which is adapted to the mirror over at least 15 °, preferably over at least 20 °, in particular over about 23.5 ° to tilt a tilting axis, wherein the tilting axis extends horizontally through the center of the turntable.
Solar power plant with a mirror for concentrating sunlight, wherein the mirror is mounted on a spatial framework-like mirror carrier incident solar light reflecting to a focus and the mirror carrier is equipped with a preferred motorized Tagesnachführung, the Tagesnachführung is adapted to rotate the mirror support about an axis of rotation and thereby the tracking the changing direction of incidence of the sun, characterized in that a control is provided, which has a focus sensor, a controller and a deformation motor, wherein the controller is data-connected to the focus sensor and is operatively connected to the deformation motor, wherein the controller is adapted to in Operation of the solar power plant to keep the focus of the collimated sunlight by means of a deformation of at least one segment of the mirror at a desired value.
PCT/DE2015/000386 2015-04-23 2015-08-04 Mirror for concentrating sunlight for a solar power installation, method for operating a solar power installation and solar power installation WO2016169537A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE102015005221 2015-04-23
DE102015005221.7 2015-04-23

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AU2015392197A AU2015392197A1 (en) 2015-04-23 2015-08-04 Mirror for concentrating sunlight for a solar power installation, method for operating a solar power installation and solar power installation
DE112015006473.7T DE112015006473A5 (en) 2015-04-23 2015-08-04 Sunlight binding mirror for a solar power plant, method for operating a solar power plant and a solar power plant
CN201580081214.9A CN107810371A (en) 2015-04-23 2015-08-04 The speculum of solar facilities aggregation sunshine, the method and solar facilities for running solar facilities

Publications (1)

Publication Number Publication Date
WO2016169537A1 true WO2016169537A1 (en) 2016-10-27

Family

ID=54608212

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2015/000386 WO2016169537A1 (en) 2015-04-23 2015-08-04 Mirror for concentrating sunlight for a solar power installation, method for operating a solar power installation and solar power installation

Country Status (4)

Country Link
CN (1) CN107810371A (en)
AU (1) AU2015392197A1 (en)
DE (2) DE112015006473A5 (en)
WO (1) WO2016169537A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108717223A (en) * 2018-05-29 2018-10-30 上海交通大学 It is tensioned platform and is tensioned platform combination device with Film Optics shape face

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1476713A1 (en) * 1963-07-13 1969-02-06 Execution De Travaux Ind Et Ru Device, in particular for the production and use of Sonnenwaerme and the wind force for generating a motor force of steam, of artificial clouds and fresh water
US6953038B1 (en) * 2000-05-22 2005-10-11 Andreas Nohrig Concentrating solar energy system
KR20100027485A (en) * 2008-09-02 2010-03-11 한국에너지기술연구원 Parabolic reflectors and manufacturing methode thereof and a condenser thereby
WO2012055431A1 (en) * 2010-10-26 2012-05-03 Roland De Vicq Sunoven and method for constructing such a sunoven
WO2012151671A1 (en) * 2011-05-10 2012-11-15 Magna International Inc. Support arm assembly

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3030033C2 (en) * 1980-08-08 1990-08-30 Bomin-Solar Gmbh & Co Kg, 7850 Loerrach, De
DE4413056C1 (en) * 1994-04-15 1995-09-28 Htc Solar Forschungscentrum Gm Multi=chambered membrane solar concentrator
DE19923141A1 (en) * 1999-05-20 2000-11-23 Tkadlec Stanislav Inflatable reflector for antenna or optical telescope, has air chamber with supporting wall, and includes metallized reflection layer with inflation inlet
WO2005057620A2 (en) * 2003-12-04 2005-06-23 Essig John Raymond Jr Modular inflatable multifunction field-deployable apparatus and methods of manufacture
CN2879046Y (en) * 2006-02-04 2007-03-14 刘晓阳 Portable solar hearth
US8469023B2 (en) * 2006-09-27 2013-06-25 Airlight Energy Ip Sa Radiation collector
CN100545693C (en) * 2007-08-14 2009-09-30 北京实力源科技开发有限责任公司 Solar-energy light collector and concentrating method
CN201107460Y (en) * 2007-08-14 2008-08-27 北京实力源科技开发有限责任公司 Solar-energy light collector
CH699605A1 (en) * 2008-09-30 2010-03-31 Airlight Energy Ip Sa Solar Panel.
CH702469A1 (en) * 2009-12-17 2011-06-30 Airlight Energy Ip Sa Parabolic collector.
EP2559147A4 (en) * 2010-04-13 2017-05-17 Shelef, Ben Solar receiver
IL217059A (en) * 2011-12-18 2015-07-30 Or Hama Energy Ltd Lightweight system and method for dynamic solar energy utilization

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1476713A1 (en) * 1963-07-13 1969-02-06 Execution De Travaux Ind Et Ru Device, in particular for the production and use of Sonnenwaerme and the wind force for generating a motor force of steam, of artificial clouds and fresh water
US6953038B1 (en) * 2000-05-22 2005-10-11 Andreas Nohrig Concentrating solar energy system
KR20100027485A (en) * 2008-09-02 2010-03-11 한국에너지기술연구원 Parabolic reflectors and manufacturing methode thereof and a condenser thereby
WO2012055431A1 (en) * 2010-10-26 2012-05-03 Roland De Vicq Sunoven and method for constructing such a sunoven
WO2012151671A1 (en) * 2011-05-10 2012-11-15 Magna International Inc. Support arm assembly

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Also Published As

Publication number Publication date
DE112015006473A5 (en) 2017-12-28
AU2015392197A1 (en) 2017-12-14
DE102015009859A1 (en) 2016-10-27
CN107810371A (en) 2018-03-16

Similar Documents

Publication Publication Date Title
AU2016222389B2 (en) Lightweight low-cost solar concentrator
US6971756B2 (en) Apparatus for collecting and converting radiant energy
ES2351242T3 (en) Cylinder-parabolic collector.
US9022020B2 (en) Linear Fresnel solar arrays and drives therefor
EP2304334B1 (en) Trough collector for a solar power plant
US4286581A (en) Solar energy conversion system
ES2444720T3 (en) Solar collector
US5542409A (en) Solar concentrator system
US4435043A (en) Composite mirror panels
US8430090B2 (en) Solar concentrator apparatus with large, multiple, co-axial dish reflectors
AU2014210668A1 (en) Linear fresnel solar arrays and components therefor
JP4852233B2 (en) Receiver tube with tubular cover and parabolic trough collector having the same
US20160010789A1 (en) Single-axis drive system and method
KR100375113B1 (en) A roof having an integral solar energy concentrating system
US7923624B2 (en) Solar concentrator system
US7878191B2 (en) Solar collector stabilized by cables and a compression element
US7192146B2 (en) Solar concentrator array with grouped adjustable elements
EP1440479B1 (en) Solar electricity generator
US9568215B2 (en) Solar central receiver system employing common positioning mechanism for heliostats
US8695341B2 (en) Systems and methods for collecting solar energy for conversion to electrical energy
EP2702334B1 (en) Device for concentrating solar radiation in an absorber
US3906927A (en) Solar-thermal power system employing adjustable curvature reflective panels and method of adjusting reflective panel curvature
US8418687B2 (en) Parabolic solar trough systems with rotary tracking means
US9851544B2 (en) Concentrating solar power with glasshouses
US4552438A (en) Cable tensioned membrane solar collector module with variable tension control

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15797583

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 112015006473

Country of ref document: DE

WWE Wipo information: entry into national phase

Ref document number: 2015797583

Country of ref document: EP

ENP Entry into the national phase in:

Ref document number: 2015392197

Country of ref document: AU

Date of ref document: 20150804

Kind code of ref document: A

REG Reference to national code

Ref country code: DE

Ref legal event code: R225

Ref document number: 112015006473

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15797583

Country of ref document: EP

Kind code of ref document: A1