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
  • F24S10/00—Solar heat collectors using working fluids
  • F24S10/90—Solar heat collectors using working fluids using internal thermosiphonic circulation
  • F24S10/95—Solar heat collectors using working fluids using internal thermosiphonic circulation having evaporator sections and condenser sections, e.g. heat pipes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S20/00—Solar heat collectors specially adapted for particular uses or environments
  • F24S20/20—Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
• • 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
  • F24S23/30—Arrangements for concentrating solar-rays for solar heat collectors with lenses
• • 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
  • F24S23/30—Arrangements for concentrating solar-rays for solar heat collectors with lenses
  • F24S23/31—Arrangements for concentrating solar-rays for solar heat collectors with lenses having discontinuous faces, e.g. Fresnel lenses
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
  • F24S40/50—Preventing overheating or overpressure
  • F24S40/52—Preventing overheating or overpressure by modifying the heat collection, e.g. by defocusing or by changing the position of heat-receiving elements
• • 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
  • F24S20/00—Solar heat collectors specially adapted for particular uses or environments
  • F24S20/20—Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
  • F24S2020/23—Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants movable or adjustable
• • 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
  • F24S2023/86—Arrangements for concentrating solar-rays for solar heat collectors with reflectors in the form of reflective coatings
• • 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
• • 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
  • Y02E10/44—Heat exchange systems
• • 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
  • Y02E10/46—Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines
• • 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 solar collector of the type comprising, as a collector, a convergent lens having, in a manner known per se, a focal distance and an image focal plane on which are concentrated, in a line, called “focus image primary ", the beam of solar rays that receives said lens, said concentrated beam moving with the course of the sun.
• a solar collector of the type comprising, as a collector, a convergent lens having, in a manner known per se, a focal distance and an image focal plane on which are concentrated, in a line, called “focus image primary ", the beam of solar rays that receives said lens, said concentrated beam moving with the course of the sun.
• Such a lens is said to be “linear” in that its focus is a line.
• the present invention proposes to provide a simple and effective solution to overcome these disadvantages.
• the present invention provides a solar collector of the aforementioned type, wherein said convergent lens constitutes one of the walls of a box defined by: two pairs of side walls, a bottom wall and a front wall constituted by said lens, the side walls of each pair being parallel to each other, and each pair of side walls being perpendicular to the other pair, the side and bottom walls, inner side of the box being reflective, the depth p between the front wall and the bottom wall being smaller than the focal length f of the lens, so that, after multiple reflections, the ray beam thus reflected is concentrated on a line called "final image focus", symmetrical to said primary image focus relative to said bottom wall and belonging to a "close-up focal plane” itself symmetrical to said image focal plane with respect to said bottom wall, but located inside said box, said sensor enclosing a movable receiver held within said concentrated beam, or in a position at least secant to said beam, by means controlling the moving said receiver to move said beam.
• the front wall and the bottom of the box are perpendicular to the side walls; in other words, the box takes the form of a rectangular parallelepiped.
• the structure of the sensor according to the invention makes it possible to follow the course of the sun, by slaving to this race, not the orientation of the box, but the position of the receiver in the box.
• the servo-control means can be considerably lighter than if it were to move the whole box and, on the other hand, that the mobile element (the receiver) is protected from the outside by the box.
• the receiver is movably mounted in the focal plane image close to said lens or in a plane parallel to said close-up focal plane.
• Servo control means that can be used are in the field of skill of the person skilled in the art. In particular, they can apply principles similar to those implemented in the known sensors.
• the receiver in the absence of solar rays or insufficient radiation, the receiver can remain temporarily immobile in the box and come to reposition relative to the concentrated beam when the radiation has recovered to a sufficient level.
• a photonic flowmeter adapted to send signals to drive means to which the heat pipe is subjected.
• the center of the receiver In order for the receiver position to be optimal, that is, to receive all the concentrated beam, the center of the receiver must be located within an area that ranges from + jc to -Jc on both sides of said close-up focal plane, median to said area, Jc satisfying the relation
• r_ is the radius of the cross-section of the receiver if this section is circular or of the circle inscribed in the section of the receiver if this section is not circular, it being understood that by “center of the receiver” is meant the line parallel to the focus final image and passing through the center of the circle;
• sin [Atan] means sinus [arc tangent];
• d is the distance between the optical axis of the lens and the edge of the lens, taken in the plane containing said optical axis and which is perpendicular to the bottom of the box and orthogonal to the final image focus.
• the converging lens can take various forms as long as it concentrates the sun's rays along a line.
• the convergent lens may be plane-convex, biconvex or convergent meniscus.
• the convergent lens will be a Fresnel lens, for reasons of reducing the size and weight of the lens.
• a Fresnel lens also has the advantage of less absorbing rays that pass through it than other lenses.
• a plano-convex Fresnel lens that is to say a lens having a flat face and a sawtooth face
• said lens will preferably be mounted so that its face plane is turned towards the outside of said box.
• This orientation has the advantage of placing inside the box the face of the lens that is most likely to trap dirt, the flat face, outside, obviously being easier to clean.
• the Fresnel lens is biconvex, i.e. a lens having a convex smooth face and a sawtooth face, the lens will preferably be mounted so that its convex face is turned towards the outside of said box.
• the lens may be a convergent meniscus lens, i.e. a lens having a convex face and a concave face; such a lens will necessarily be mounted so that its convex face is facing outwardly of said box.
• the receiver is advantageously a heat pipe covered with a material whose absorption coefficient of the heat is greater than the heat emission coefficient.
• the heat pipe takes the form of a tube, possibly flexible, included in a vacuum tube, to limit the heat loss.
• the heat pipe is advantageously connected to an extraction exchanger fed with a heat transfer fluid to exploit the heat obtained, for example to heat water or another fluid, to heat a device or to generate solar cold.
• the receiver is an extraction exchanger supplied with a heat transfer fluid.
• the receiver may be a photovoltaic cell receiver.
• the receiver is capable of occupying two positions, namely a service position in which it receives a certain thermal energy and a retracted position in which it receives a lower thermal energy than in the service position.
• retractable means being able to move the receiver from its operating position to its retracted position, in the event of risk of overheating, for example, in the event that the circulation of coolant no longer occurs in the extraction exchanger .
• the receiver can be connected to a Stirling engine, that is to say an engine that exploits a temperature difference between a hot source and a cold source, especially for the purpose of generating electricity.
• a Stirling engine that is to say an engine that exploits a temperature difference between a hot source and a cold source, especially for the purpose of generating electricity.
• the surfaces of the lens are treated so as to reduce their potential deterioration with time, alterations which may consist, mainly on the outside, in soiling, and on the inner side in depositing metal particles ejected from the reflective surfaces.
• Such treatment may consist of a non-stick surface treatment increasing the wettability and obtained by application of thin layers consisting of SiOx-based compounds (SiO 2, etc.) and / or coatings which make it possible to reduce the adhesion of various pollutants, such as TiO 2 type photocatalytic compounds.
• Such an antireflection treatment has, in addition, the advantage of reducing the reflection, by the lens, the rays it receives according to certain incidences.
• the reflective walls alternatively, they may be made of removable reflective panels for cleaning, replacement or complete flattening of the box for transport or displacement.
• FIG. 1 is a diagram, in perspective, cutaway, of an embodiment of a box according to the invention
• FIGS. 2a, 2b and 2c illustrate various types of lenses that can be used according to the invention with identification of the thickness e_;
• FIGS. 3a and 3b are diagrams of one embodiment of the box according to the invention, illustrating the effect of the useful distance b on the depth of the box;
• FIGS. 4a and 4b are diagrams of one embodiment of a box according to the invention, seen in section in a plane perpendicular to the general direction of the lens, and illustrating the path of the solar rays in two angles. different;
• FIGS. 5a and 5b are diagrams illustrating the parameter k and the optimal positioning zone of the receiver, FIG. 5b being a view on a larger scale of the area of the final image focus of FIG. 5a, and
• the casing 1, in this embodiment of the invention is of rectangular parallelepipedal shape, composed of a front wall consisting of a linear converging lens 2, a rear wall or bottom 3 and side walls 4a-d.
• the inner faces of the side walls 4a-d and bottom 3 of the box 1 are reflective, either they are coated with a reflective film or they are lined with a removable reflective wall.
• the side wall 4b has a slot such as 5, in which is slidable a heat pipe 6 in a plane parallel to the general plane of the lens 2, the heat pipe being supported, opposite the slot, by appropriate means (not shown) allowing this sliding.
• the heat pipe 6 is sheathed with a material having a heat dissipation coefficient lower than its thermal absorption coefficient to limit the losses as much as possible.
• the casing 1 is extended by a housing 8 (dashed in FIG. 1) for the extraction exchanger 7 and a drive mechanism not shown in FIG. 1
• the housing 8 may have the same rectangular section as the casing 1 and be closely connected to avoid infiltration of rainwater or dust. It can be advantageously opaque to slow the aging of the hoses 9a and 9b ( Figure 6).
• the lens 2 of the box 1 is struck by the sun's rays at an incidence that varies with the time of day, the season, and so on. and two such different incidences are illustrated by the rays R and R 1 . If we come to the optical plane, FIG. 4a, which represents the casing 1 without the heat pipe 6 nor the extraction exchanger 7 for the clarity of the representation, we see that the lens 2 is constituted by a lens of Fresnel 2 convex plane whose flat face is turned towards the outside of the box.
• the thickness of the lens has been exaggerated in the figure also for the sake of clarity.
• the lens 2 has an optical axis AA, a focal length f greater than the depth p of the box 1 and an image focal plane PFI which is beyond the bottom 3 of said box 1.
• FIGS. 2a, 2b and 2c respectively show a plano-convex lens 2a, in this case a Fresnel lens, a biconvex lens 2b, and a meniscus lens 2c, forming one of the walls of a box which can be seen in FIG. primer of the side walls 4a and 4c.
• the plane face of the lens coincides with the plane FF passing through the adjacent edge of the side walls 4a-4d, and the penetration thickness e is the distance between this plane FF and the TT plane tangent to the most prominent part of the lens inside the box.
• the thickness e_ of penetration is the distance between the median plane of the lens, which is confuses with the plane FF, passing through the adjacent edge of the side walls 4a-4d, and the plane TT tangent to the most prominent part of the lens inside the box.
• the thickness e_ is substantially zero.
• FIGS. 3a and 3b where the lens has been schematized in the form of a simple rectangle designated 2a-c, to show that it may be any of the types of lenses 2a, 2b or 2c illustrated in Figures 2a to 2c, the parameters necessary for the determination of the depth of the box are indicated.
• the lens 2a-c has a thickness e_ and a focal distance f_, which distance determines the image focal plane PFI.
• the receiver 6 is in the plane PFIR situated at e + b1 of the plane FF, which is a special case, as will be seen with reference to FIGS. 5a and 5b.
• the bottom 3 of the box must be equidistant from the PFIR plane and the PFI plane.
• sun rays striking the lens 2 parallel to the ray R would focus on a primary image focus in the image focal plane PFI.
• the lateral reflecting walls, such as 4a, and the reflecting bottom 3 of the box stop the R-rays and reflect them until they focus on a final image focal point, in a close-up image plane PFIR parallel to the plane focal image PFI, but inside the box 1.
• this final image focus is seen in section, thus in the form of a point I.
• FIG. 4b is similar to FIG. 4a except that it illustrates another orientation of impact of the rays, such as R ', on the lens 2. As can be seen, at the end of multiple reflections, these rays R 'focus on a final image focus, also located in the PFIR plane, and this final image focus is seen in section in Figure 4b, thus in the form of a point I'.
• the final image focus of the R-rays and that of the R 'rays are located in the same plane PFIR, but along two different lines or, expressed otherwise, the linear final image focus moves in translation in the plane PFIR as and when measure of the sun's course.
• the heat pipe 6 which, in the particular case envisaged, is arranged in the plane PFIR, moves to follow this displacement in translation of the final linear image focus.
• motor means enslaving the displacement of the heat pipe to the race of the sun, or more precisely to the race of the concentrated ray beam towards the final image focus. This enslavement takes into account the location of the caisson, the season, the time of day, etc.
• the heat pipe may, in addition, be subjected to retractable means adapted to move it, if necessary, out of its operating position, to avoid overheating.
• the retracting means will move the heat pipe from its service position where it receives a certain thermal energy to a retracted position where it receives a lower thermal energy than in the service position.
• FIG. 5a there is the box 1 with its lens 2 and its bottom 3. It also shows a receiver 6a which has been presented in the form of a circular section device of radius r (see Figure 5b), but not necessarily circular. If the receiver is not circular, consider the circle in the non-circular section. The distance d used in the calculation of the value I is also identified in this figure.
• R 1 and R ⁇ are indicated solar rays forming the outer boundaries of the beam of rays striking the lens 2 with zero incidence.
• the beam bounded by Ri and R 2 converges towards the plane PFI but is stopped and reflected by the bottom 3 to converge in a concentrated beam towards the plane PFIR that crosses along a line seen in section I ", corresponding to the focus image final, to diverge beyond the RETP plan.
• concentrated beam thus delimits, on either side of the final image center I ", two X planes forming an angle ⁇ between them.
• the receiver receives the entire concentrated beam.
• a part of the concentrated beam namely the part which lies between, respectively, the plane of R 1 and R 2 and the tangents T 1 and T 2 to the receiver 6c do not hit the receiver.
• the line which passes through the center of the receiver and which is parallel to the final image focus I "(line C 3 for the receiver in position 6a, line C b for the receiver in position 6b) must be located in a zone of extent E ranging from + k to -k, on either side of the plane PFIR, k having to satisfy the relation
• positions 6a, 6b and 6c could just as easily be on the other side of the PFIR plane.
• FIG. 5b shows, in addition, for the receiver 6a a service position (in this case, within the beam concentrated and tangent to the planes bounding this beam) and a retracted position, illustrated in 6a 'or the receiver is totally out of the concentrated beam.
• the position ⁇ c could also be considered to constitute the retracted position of the receiver 6a.
• references E1 and E8 respectively designate the interior space of the box 1 and the interior space of the housing 8, separated by the partition 4b, slotted at 5.
• the heat pipe 6 and the exchanger 7 with its cold fluid supply according to 7a and its discharge in hot fluid according to 7b, as shown in FIG. 1. More specifically, this supply and this evacuation are done via flexible hoses, respectively 9a and 9b, connected to tubings, respectively 10a and 10b, themselves in fluid communication with the inside of the exchanger 7.
• Flexible tubes 9a and 9b are used, obviously, to allow the displacement of the heat pipe 6.
• the heat pipe 6 is connected, via a collar 11 provided with a fork 12a, 12b, to the axis of rotation of a pinion 13 which meshes with a rack 14, pinion 13 which is itself driven in rotation by a motor 15.
• the lens and the bottom of the box are not necessarily perpendicular to the side walls of said box, and not necessarily parallel to each other.
• the box could contain an extraction exchanger supplied with heat transfer fluid or a linear volume coated with photovoltaic cells, both mobile as has been described for the heat pipe.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Photovoltaic Devices (AREA)
• Optical Radar Systems And Details Thereof (AREA)
• Optical Elements Other Than Lenses (AREA)
• Lenses (AREA)

Applications Claiming Priority (3)

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• 2007
  • 2007-05-25 FR FR0703712A patent/FR2927155B1/fr not_active Expired - Fee Related
• 2008
  • 2008-03-03 BR BRPI0808429-7A patent/BRPI0808429A2/pt not_active IP Right Cessation
  • 2008-03-03 AU AU2008244185A patent/AU2008244185B2/en not_active Ceased
  • 2008-03-03 JP JP2009552243A patent/JP5253420B2/ja not_active Expired - Fee Related
  • 2008-03-03 US US12/530,009 patent/US20100024801A1/en not_active Abandoned
  • 2008-03-03 EP EP08775618A patent/EP2129974A2/de not_active Withdrawn
  • 2008-03-03 WO PCT/FR2008/000275 patent/WO2008132300A2/fr not_active Ceased
• 2009
  • 2009-09-06 EG EG2009091319A patent/EG25794A/xx active
  • 2009-09-11 MA MA32216A patent/MA31249B1/fr unknown

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