Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
  • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
  • F24S23/77—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with flat reflective plates
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S30/00—Arrangements for moving or orienting solar heat collector modules
  • F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
  • F24S30/42—Arrangements for moving or orienting solar heat collector modules for rotary movement with only one rotation axis
  • F24S30/425—Horizontal axis
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S50/00—Arrangements for controlling solar heat collectors
  • F24S50/20—Arrangements for controlling solar heat collectors for tracking
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
  • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
  • F24S2023/85—Micro-reflectors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
  • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
  • F24S2023/87—Reflectors layout
  • F24S2023/872—Assemblies of spaced reflective elements on common support, e.g. Fresnel reflectors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S30/00—Arrangements for moving or orienting solar heat collector modules
  • F24S2030/10—Special components
  • F24S2030/11—Driving means
• • Y—GENERAL 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/40—Solar thermal energy, e.g. solar towers
  • Y02E10/47—Mountings or tracking

Definitions

• the present invention relates to a device for concentrating incident light, in particular of sunlight, consisting of a plurality of adjacently arranged reflector units each having at least one movable reflective surface and a drive unit for moving the reflecting surface, and a control unit. which is connected to the drive units and which is designed such that it controls the drive units as a function of the incidence of light to the concentration of the incident light.
• the present device is mainly used in solar energy technology, in particular for the concentration of sunlight in solar thermal or photovoltaic systems for energy production or for decentralized solar cogeneration.
• the Vorrich ⁇ device allows the concentration of sunlight on any geometry, for example a saudi ⁇ dimensional absorber surface of a solar system or an approximately one-dimensional tube absorber, as it is known from parabolic trough concentrators.
• the line-concentrating systems include the so-called parabolic trough concentrators, as they come from, for example, DE 197 44 767 C2 or US Pat. No. 4,423,719, in which the incident parallel solar radiation is line-shaped through one or more parabolic reflecting surfaces Absorber tube, for example described in DE 102 31 467 B4, kon ⁇ centered.
• Parabolic trough concentrators are used in so-called SEGS power plants (Solar Energy Generating Systems), which achieve outputs in the order of magnitude of 50 MW and above.
• the absorber tube is usually surrounded by an evacuated glass tube.
• a cross section through a parabolic trough concentrator is shown in FIG. It shows how incident parallel light 7 is reflected by the parabolic shaped reflecting surface 2 onto the absorber tube 8.
• the absorber tube 8 is surrounded by the evacuated glass tube 9.
• the absorber tube 8 or the glass tube 9 is supported by a holder every 2 to 6 meters, depending on the size of the parabolic trough concentrator.
• the glass tube 9 is connected at this point usually via a bellows with the absorber tube 8. In the case of today's parabolic trough concentrators, this area is subjected to the same radiation density as the area in between.
• the point-concentrating plants include, for example, solar thermal power plants.
• a heat transfer medium With the heat transfer medium, a conventional heat power process is operated. The resulting heat and the process steam can be stored, decoupled and converted into electricity.
• the known heliostats of solar thermal systems have at least one, usually several reflector (mirror) with a mirror surface of several square meters to the order of 100 square meters and more.
• the construction of a helicopter today usually comprises a steel girder construction which absorbs the wind and weight loads. Mounted thereon is one or several reflecting surfaces, which as a rule consist of a glass plate mirrored on the back side. Other reflective elements include silver-coated polymers and thin-glass mirrors.
• the steel girder construction is connected with a linkage with corresponding drive, which allows movements of the steel girder construction by one or two independent axes.
• the control unit controls the articulation of the steel girder construction of the respective heliostats depending on the position of the sun so that the sunlight is always concentrated on the absorber surface.
• the articulation of the steel girder construction itself is usually mounted at a height of several meters above the ground, for example on a vertical mast.
• the glass mirrors used today have a thickness of 3 mm to 5 mm for reasons of strength.
• the dimensioning of the steel girder construction results from the maximum wind speed at which the mirrors are still to be used, whereby there is still sufficient
• FIG. 4 shows five known forms of heliostats which have been developed for the concentration of solar radiation. The different sizes of the illustrated heliostats reflect the size relationships. The realized mirror surface ranges from a few square meters up to about 150 square meters per helicopter.
• Figure 5 the principle of a known solar tower power plant is shown. It shows an array of heliostats 10 arranged on the earth's surface whose reflective surfaces 2 are arranged in the contour of a paraboloid which has a focal point 11 of the reflected radiation on the absorber surface for incident, parallel sunlight 7.
• a disadvantage of the known parabolic trough concentrators as well as the known heliostats is also that they require a considerable effort for the cleaning of the plants, since the large Spiegelflä ⁇ chen are often accessible only via lifts for the madesper ⁇ sonal.
• the solar energy concentrators described above in particular the heliostats used, have high material and manufac turing costs and a high weight. If one considers the specific weight in relation to the mirror surface of today's common heliostats, then this lies between 25 kg / m 2 and 60 kg / m 2 mirror surface. This weight is based on the necessary stiffness of the heliostats and can hardly be lowered for the same or similar embodiments for static reasons. Experiments with lightweight materials yielded no significant advantages because of the associated higher material costs.
• the object of the present invention is to provide a device for concentrating incident light, in particular sunlight, in such a way that the listed disadvantages resulting from the prior art are avoided, and the device has a smaller effect on the reflective surface ⁇ che referred, specific weight and kos ⁇ ten redesigner is produced.
• the device according to the invention for concentrating incident light, in particular sunlight consists of a plurality of reflector units arranged side by side, each having at least one movable reflective surface and a drive unit for moving the reflecting surface, and a control unit connected to the Drive units ver ⁇ is connected and which is designed such that it controls the drive units in dependence of the light incidence to the concentration of the incident light.
• the device is characterized in that the at least one reflective surface of a respective reflector unit has an area between 10 -8 m 2 and 0.5 m 2 , in particular between 10 -8 m 2 and 10 -4 m 2 and is movable by at least 2 axes, and that the drive units are microactuators.
• the reflector units of the present device with low heights are few Millimeters to a few decimetres producible bar.
• microactuators can be used as microactuators.
• the microactuator can also be a piezoelectric transducer or at least one piezoelectric transducer.
• the microactuators are connected to and controlled by a control unit. After a corresponding signal from the control unit, the microactuators move the reflecting surface of a reflector unit to a desired position. By thus changing the angle between the direction of incidence of the incident light and the reflecting surface, the direction of the reflected radiation can be directly influenced and controlled.
• the microactuators are designed and arranged such that, in the event of a power failure, they bring the reflecting surfaces of the reflector units into a starting position in which no concentrating effect for incident light occurs.
• This starting position can be a horizontal position be. This prevents overheating of the absorber surface.
• the reflective surface of a reflector unit is flat in the preferred embodiment and consists of a single mirror, in particular an anodized aluminum mirror, a membrane mirror or a silver-coated polymer mirror.
• the reflecting surface may be formed differently two- or dreidimen ⁇ sionale, for example, be concavely curved or arched ge. In the latter case, an additional concentration of the incident light occurs due to the reflection at the reflecting surface.
• the device according to the invention comprises a plurality of reflector units arranged side by side.
• the reflector units are preferably arranged in one or more arrays horizontally or at ground level or only slightly inclined and firmly mounted.
• the control unit is designed in such a way that it controls the reflector units combined into arrays, ie the respective drive units individually or in groups in at least two independent axes of motion.
• the individual reflecting surfaces must, according to the existing, fixed arrangement geometry of the reflector units and the projection surface, depend on a possibly variable position of the light source, for example of the sun. controlled were ⁇ the.
• the control unit is therefore designed in an embodiment for compensating the variable position of the sun such that it contains the microactuators and thus the reflecting surfaces of the reflector units controls according to a sun position algorithm.
• the current position of the sun is determined by the control unit by means of one or more suitable radiation sensors and used to control the microactuators.
• a light-transparent cover can be installed above the reflector units for additional protection against the influence of wind, soiling or other environmental influences.
• lateral enclosures can be provided which can be provided for better protection of the device with the transparent cover.
• the transparent cover should advantageously be mirrored on one or both sides.
• the device in addition, it is possible to construct the device as a complete unit.
• the reflector units are mounted on a base plate and, together with the lateral enclosures fixed thereto and the transparent cover, form a structural unit with a height of a few millimeters to a few decimetres.
• an automatic or semi-automatic cleaning system can be provided for cleaning the transparent cover.
• Main field of application of the present device is the solar energy technology.
• it can also be used for optical systems for image projection, for example for advertising purposes or for daylighting and daylighting in buildings.
• the device according to the invention fulfills the condition of a small radiation image to a particular extent by means of the very small and flat individual mirror.
• the device according to the invention makes it possible to reduce the weight and thus the material cost to a few kg / qm mirror surface and thus offers a high cost reduction potential.
• the individual reflecting surfaces move back into a horizontal orientation and defocus, for example the picture (radiation on the absorber surface).
• the system costs, for example, of a solar thermal power plant are reduced, because a fast emergency power supply for the reflector units can be dispensed with.
• the fast emergency power supply is required in today's heliostats, as they remain in position in case of power failure, which can lead to the destruction of the then uncooled absorber.
• structural measures are taken to cool the absorber.
• the achievable flat design allows integration of the concentrator as facade element or roof element. This results in completely new applications, e.g. in daylight use via light pipes.
• the device according to the invention is able to generate high concentrations of light (> 1,000kw / m) in variable focal points. This makes it possible for the first time to create small decentralized power plant units (for example with Sterling Motor) that can be used on coaxial and flat roofs for combined heat and power generation.
• small decentralized power plant units for example with Sterling Motor
• the device according to the invention allows almost any illumination of a picture surface.
• it is particularly suitable for combination with solar cells for the generation of photovoltaic electricity from concentrated solar radiation, since it guarantees a nearly homogeneous illumination of the solar cells with regard to the radiation density.
• the energy input per cell or a number of cells can be detected, e.g. By resistance measurement, the radiation flux distribution to the cells can be controlled by controlling the individual reflector units according to an optimal energetic use of the radiation.
• the device according to the invention is also suitable for generating a linear imaging of the incident radiation, as is the case in parabolic trough concentrators.
• the radiation can be directed at any time so that all radiation falls exclusively onto the absorber tube and the bellows connections are excluded from the irradiation.
• the present loss due to the irradiation of the bellows corresponds to about 5% of the concentrated radiation of a parabolic trough power plant.
• parabolic trough concentrators known today are tilted / rotated only in one axis according to the instantaneous position of the sun, part of the radiation always passes at the ends of the parabolic concentrator due to the non-perpendicular incidence of the radiation in the axial direction of the parabolic trough concentrator lost. This can also be avoided by the device according to the invention by controlling the individual reflecting surfaces.
• the ability to concentrate and direct the reflected light better achieves an increase in efficiency. As a result, mirror surface can be saved or a higher light output can be achieved with the same mirror surface.
• the reflector units can also be operated at higher wind speeds, which results in options for use on the coast or in the offshore area.
• FIG. 1 a array-shaped arrangement of reflector units with square reflecting surfaces, 1b, c show cross sections through the array of FIG. 1a along the section lines AA (FIG. 1b) and BB (FIG. 1c), FIG.
• FIG 3 is a schematic cross-sectional view of a parabolic trough concentrator with beam path (prior art)
• FIG. 4 schematic representation of known heliostats (prior art).
• Fig. 5 is a schematic representation of a solar thermal power plant with arranged heliostats and a raised attached absorber surface
• FIG. 1 a schematically illustrates an array-shaped arrangement of reflector units 1 according to the invention with individual rectangular reflecting surfaces 2.
• the reflecting surfaces 2 of the individual reflector units 1 are movable about two independent axes of movement 3.
• FIGS. 1 b and 1 c the positions of the individual reflecting surfaces 2 along the section lines AA and BB are represented by the array of reflective surfaces.
• Gate units 1 represents in the case of a nearly point-like concentration of the incident parallel light darge.
• the reflector units 1 are mounted on a bottom plate 4.
• the array of reflector units 1 is encompassed by a lateral border 5 and a transparent cover plate 6 which are firmly fixed to each other and to the bottom plate 4.
• FIG. 2 shows schematically the beam path which occurs according to FIGS. 1 b and 1 c.
• the reflector units can be controlled individually or in groups in other, not shown, applications of the device according to the invention Vor ⁇ direction by an appropriately trained Steuer ⁇ that from arbitrary radiation sources such as spotlights (light bulb) tube radiators (fluorescent tube) or pa ⁇ rallelem light (sun) Images with almost beechi ⁇ ger geometry (punctiform, rectangular, linear, broken lines, etc.) is generated.
• arbitrary radiation sources such as spotlights (light bulb) tube radiators (fluorescent tube) or pa ⁇ rallelem light (sun)
• FIGS. 3 to 5 represent devices of the prior art and have already been described in greater detail in the description of the description.

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Cited By (8)

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Citations (24)

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• 2004
  • 2004-11-12 DE DE102004054755A patent/DE102004054755B4/de not_active Expired - Fee Related
• 2005
  • 2005-07-04 WO PCT/DE2005/001171 patent/WO2006005303A1/de active Application Filing
  • 2005-07-04 EP EP05763326A patent/EP1771687A1/de not_active Withdrawn

Patent Citations (24)

Non-Patent Citations (6)

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