WO2008092195A1 - Ferme solaire à dispositif anticollision - Google Patents

Ferme solaire à dispositif anticollision Download PDF

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Publication number
WO2008092195A1
WO2008092195A1 PCT/AU2008/000096 AU2008000096W WO2008092195A1 WO 2008092195 A1 WO2008092195 A1 WO 2008092195A1 AU 2008000096 W AU2008000096 W AU 2008000096W WO 2008092195 A1 WO2008092195 A1 WO 2008092195A1
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WO
WIPO (PCT)
Prior art keywords
reflector
collision
array
heliostat
heliostats
Prior art date
Application number
PCT/AU2008/000096
Other languages
English (en)
Inventor
David Mills
Peter Le Lievre
Andrew Tanner
Original Assignee
Solar Heat And Power Pty Ltd
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 claimed from AU2007900390A external-priority patent/AU2007900390A0/en
Application filed by Solar Heat And Power Pty Ltd filed Critical Solar Heat And Power Pty Ltd
Publication of WO2008092195A1 publication Critical patent/WO2008092195A1/fr

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Classifications

    • 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
    • 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
    • F24S30/45—Arrangements for moving or orienting solar heat collector modules for rotary movement with two rotation axes
    • F24S30/455—Horizontal primary axis
    • 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
    • F24S2023/83—Other shapes
    • F24S2023/832—Other shapes curved
    • 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
    • F24S2030/13—Transmissions
    • F24S2030/131—Transmissions in the form of articulated bars
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S25/00—Arrangement of stationary mountings or supports for solar heat collector modules
    • F24S25/10—Arrangement of stationary mountings or supports for solar heat collector modules extending in directions away from a supporting surface
    • 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

  • This invention relates to a solar energy collector system that employs a field of heliostats for reflecting incident solar radiation to at least one target receiver.
  • the invention has application in the reflection and concentration of solar energy for such purposes as generating steam, heating various types of fluids, e.g., heat transfer fluids, contributing to chemical processing, such as in reforming processes, and irradiating photovoltaic cells.
  • Solar energy collector fields have been proposed and constructed for reflecting incident radiation toward at least one, e.g., tower-mounted receiver or absorber.
  • An example of one such field arrangement is provided in U.S. Patent No. 4,117,682.
  • each heliostat In collector fields that employ a plurality of separate heliostats for concentrating radiation on a receiver, each heliostat conventionally has a reflector structure that pivots about a fixed vertical axis for azimuthal tracking and about a horizontal axis (that is itself rotated about the vertical fixed axis) for tracking in elevation. Examples of such heliostats are disclosed in U.S. Patent Publication No. 2005/279953 (Gerst, published December 22, 2005) and International Patent Publication No. WO05/098327 (Yutaka et al., published October 20, 2005). An alternative heliostat arrangement is disclosed in
  • a reflector element for example, a hexagonally shaped reflector element
  • a carrier that is pivotal about an axis that is, as described, disposed parallel to the ground plane, with the axis of the reflector element being not parallel to the pivot axis of the carrier. Attention has been given to the maximization of energy concentration by maximizing the number of heliostats in a given field and by minimizing the so-called dead area; that is, by minimizing the spacing between adjacent rows and columns of the heliostats.
  • MTSA multi-tower solar array
  • Methods and systems that can reduce the probability of collisions between reflectors in a heliostat field are desired, particularly for closely-packed heliostat fields and/or when the heliostat fields comprise heliostats that have fixed vertical axes.
  • Solar energy collector arrays are described here that comprises at least one field of heliostats arranged to reflect incident solar radiation to at least one target receiver, e.g., a tower-mounted target receiver. Also disclosed here are methods, systems, and related computer programs, for detecting and avoiding collisions between heliostat reflector structures in a solar energy collector array.
  • heliostats in the solar energy collector arrays that are described here comprise a reflector structure that, in turn, comprises a reflector element arranged in use to pivot about first and second orthogonal axes and to reflect incident solar radiation to one ore more target receivers.
  • First and second actuators arranged when actuated to effect pivotal movement of the reflector structure about the first and second axes.
  • one of the first and second axes may be a fixed vertical axis or a fixed horizontal axis.
  • the solar energy collector arrays may also include a collision avoidance monitoring system that is configured to monitor the position to be occupied by the reflector structure of each heliostat in the array by reference to actuating signals to be delivered to the first and/or second actuators and detect for the potential for collision between two adjacent reflector structures by reference to the monitored positions to be occupied by the respective adjacent reflector structures.
  • a collision avoidance monitoring system that is configured to monitor the position to be occupied by the reflector structure of each heliostat in the array by reference to actuating signals to be delivered to the first and/or second actuators and detect for the potential for collision between two adjacent reflector structures by reference to the monitored positions to be occupied by the respective adjacent reflector structures.
  • solar energy collector arrays comprise two or more heliostats arranged to reflect solar radiation to at least one target receiver.
  • Each heliostat comprises a reflector structure comprising a reflector element arranged in use to reflect incident solar radiation to a target receiver, a vertically extending support member, first and second actuators configured to position the reflector structure, and a linkage coupling the reflector structure to the vertically extending support member.
  • the linkage is configured to confine rotation of the reflector structure to a collision volume.
  • the arrays also comprise a collision avoidance system that is provided to monitor the position of the reflector structure, and to detect for potential for collision by reference to the collision volume of the reflector structure, and collision volumes of one or more other reflector structures in the array, hi some of these arrays, the position of the reflector structures in the arrays may be monitored by reference to actuating signals to be delivered to and/or received from the first and second actuators.
  • a collision avoidance system that is provided to monitor the position of the reflector structure, and to detect for potential for collision by reference to the collision volume of the reflector structure, and collision volumes of one or more other reflector structures in the array, hi some of these arrays, the position of the reflector structures in the arrays may be monitored by reference to actuating signals to be delivered to and/or received from the first and second actuators.
  • the linkage may be configured to confine rotation of the reflector structure to at least a portion of a horizontally oriented central slice of a sphere, or to at least a portion of a vertically oriented central slice of a sphere, hi some of these latter arrays, the heliostats may be close-packed in a side-to-side arrangement with a vertical plane of a collision volume of one reflector structure adjacent to and aligned with a vertical plane of a collision volume of another reflector structure.
  • the methods comprise providing a three-dimensional numerical reflector representation to represent each reflector in at least a portion of an array.
  • Each three-dimensional numerical reflector representation stores dimensional data and three- dimensional positional data for its associated reflector.
  • the methods include arranging the three-dimensional numerical reflector representations to simulate at least the portion of the array.
  • the position of each reflector e.g., azimuth angle and zenith angle
  • may be tracked, and updated positional data may be stored with its associated numerical reflector representation.
  • a potential collision between reflectors may be detected by an intersection between any two numerical reflector representations.
  • the numerical reflector representation of at least one reflector in an array may have at least one dimension oversized relative to the actual scale of the reflector it represents.
  • the position of at least one reflector may be tracked in substantially real time to obtain updated positional data.
  • the methods may include updating positional data for at least one reflector with a lag time of less than about 2 seconds.
  • a desired positional move for a reflector in a heliostat may be simulated before that desired movement is initiated or carried out.
  • These methods include providing a three- dimensional numerical reflector representation to represent each reflector in at least a portion of an array, wherein each three-dimensional numerical reflector representation stores dimensional data and positional data for its associated reflector.
  • the numerical reflector representations may be arranged to simulate at least the portion of the array.
  • a movement for a first numerical reflector representation may be simulated to simulate a desired movement of a corresponding first reflector.
  • a potential collision between the first reflector and another reflector in the array may be detected by an intersection between the first numerical reflector representation and any other numerical reflector representation in the simulated array upon simulated movement of the first numerical reflector representation.
  • the methods and systems described may incorporate a variety of responses.
  • the methods may include manually overriding automatic movement of a reflector temporarily to effect manual actuation of the reflector of at least one of two potentially colliding heliostats in a manner to avoid collision.
  • the methods may include moving a first of two reflectors involved in a potential collision temporarily to a park position that avoids collision and, after moving the second reflector second to its required position, then moving the first reflector from the park position to its required position.
  • movement of one of two reflectors implicated in a potential collision may be delayed until the other reflector has been moved beyond a potential collision point.
  • Some methods may comprise automatically stopping movement of an affected reflector to avoid a potential collision and/or alerting an operator of the detection of a potential collision.
  • Some methods and/or systems may incorporate a combination of these responses.
  • Methods for causing a heliostat to track the position of the sun comprise determining a desired three-dimensional reflector position of a heliostat based on the position of the sun and the position of a target receiver.
  • the methods include converting the desired reflector position to first and second displacements.
  • a reflector of a heliostat is then moved to the desired position by linearly translating a first linear actuator (e.g., a linear actuator configured to change an azimuthal angle of the reflector) by a distance corresponding the first displacement, and linearly translating a second linear actuator (e.g., a linear actuator configured to change a zenith angle of the reflector) by a distance corresponding to the second displacement.
  • a first linear actuator e.g., a linear actuator configured to change an azimuthal angle of the reflector
  • a second linear actuator e.g., a linear actuator configured to change a zenith angle of the reflector
  • Computer programs encoding these methods, computer-readable storage media comprising computer-executable instructions for carrying out the methods, and systems are also provided.
  • the methods for detecting and avoiding collisions may be used in any suitable solar energy collector array, and in particular, may be used in solar energy collector arrays comprising fixed vertical axis heliostats.
  • FIG. 1 illustrates a rear perspective view of a variation of a heliostat with a tilted reflector structure.
  • FIG. 2 illustrates a side view of the variation of the heliostat shown in FIG. 1.
  • FIG. 3 shows a side view of the variation of the heliostat shown in FIG. 1, with a reflector structure tilted in a generally forward, upward- facing direction.
  • FIG. 4 illustrates a side view of the variation of a heliostat shown in FIG. 1, with a reflector structure tilted in a generally forward-facing direction.
  • FIG. 5 illustrates a rear view of the variation of the heliostat shown in FIG. 1.
  • FIG. 6 shows on an enlarged scale relative to FIG. 1 a carrier-mounting member of the heliostat.
  • FIGS. 7 A to 7D illustrate multiple views of another variation of a heliostat.
  • FIGS. 8 A to 8E provide multiple views of a variation of vertically extending support member that may be used with the heliostats described here.
  • FIGS. 9 A to 9C provide multiple views of a variation of a carrier-mounting member that may be used with the heliostats described here.
  • FIG. 10 illustrates another variation of a linkage between a vertically extending support member and a reflector structure that may be used with heliostats described here.
  • FIGS. 1 IA and 1 IB illustrate a variation of a heliostat having a fixed vertical pivot axis.
  • FIG. 12 illustrates an example of a vertically oriented central slice of a generally spherical volume traced out by rotation of a heliostat reflector structure about the first and second rotational axes.
  • FIG. 13 illustrates an example of a horizontally-oriented central slice of a generally spherical volume traced out by rotation of a heliostat reflector structure about the first and second rotational axes.
  • FIG. 14 shows a front, perspective view of a variation of a reflector structure with a reflector element partially cut away to reveal a carrier.
  • FIGS. 15A and 15B illustrate one variation of a method for securing a reflector element to a carrier.
  • FIG. 15B is a view along axis "A" shown in FIG. 15 A.
  • FIGS. 16A and 16B illustrate another variation of a method for securing a reflective element to a carrier.
  • FIG. 16B is a view along axis "B" as shown in FIG. 16A.
  • FIG. 17A is a diagrammatic representation of an example of a solar energy collector system having a generally rectangular field of heliostats and two target receivers.
  • FIG. 17B is a diagrammatic representation of another example of a solar energy collector system having two contiguous, generally rectangular fields of heliostats, each of which has a single target receiver.
  • FIG. 18 provides a diagrammatic representation of an example of a control/monitoring system that may be used for some variations of heliostats, e.g., heliostats in solar collector fields of FIGS. 17A and 17B.
  • FIG. 19 illustrates an example of a potential collision as detected by the intersection of two collision volumes.
  • FIG. 20 shows a flow chart for a variation of a method for avoiding collisions.
  • FIG. 21 shows a flow chart for another variation of a method for avoiding collisions
  • FIG. 22 illustrates a flow chart for a variation of a method for tracking the position of a reflector structure.
  • FIGS. 23A and 23B illustrate heliostat geometries.
  • FIG. 24 illustrates a function for converting an angle (e.g., an azimuthal or zenith angle) to a linear displacement.
  • an angle e.g., an azimuthal or zenith angle
  • the arrays may have any configuration, and in some cases are multi-tower solar arrays.
  • the reflector elements of the heliostats in the arrays may be moved to track diurnal motion of the sun.
  • the heliostats may be selected to allow relatively close side-to-side packing with a reduced probability of inter-reflector collisions.
  • a collision avoidance system may be employed with the arrays.
  • Methods for detecting and avoiding inter-reflector collisions in solar arrays comprising heliostats are described here, as well as methods for positioning heliostat reflectors, and for detecting positioning of heliostat reflectors.
  • the methods and systems described here may in general be used in connection with any type of heliostat, e.g., fixed vertical axis heliostats and/or fixed horizontal axis heliostats.
  • the solar energy collector arrays may comprise heliostats that comprise a reflector structure mounted on a support member, e.g., a vertically extending support member.
  • the reflector structure may be positioned to track diurnal motion of the sun, to direct incident solar radiation to a target receiver, e.g., a tower-mounted receiver, and/or to a stow or parked position.
  • the reflector structure of a heliostat comprises a reflective element that may be curved (e.g., cylindrical or spherical) to focus and concentrate the solar radiation, e.g., at a target receiver, or may be planar.
  • the reflector structure is coupled to the vertically extending support member via a linkage that is configured to support the reflector structure and to allow rotation around a first rotational axis, and rotation around a second rotational axis that is substantially orthogonal to the first rotational axis.
  • the heliostats may comprise a first actuator configured to effect rotation around the first rotational axis, and/or a second actuator configured to effect rotation around the second rotational axis. At least one of the first and second actuators may be a linear actuator. In some variations, both the first and second actuators are linear actuators.
  • the heliostats described here may be configured as fixed horizontal axis heliostats, where the reflector structure of each heliostat may be continuously positioned over at least a portion of a substantially vertical central slice of a generally spherical space, or as fixed vertical axis heliostats, where the reflector structure of each heliostat may be continuously positioned over a at least a portion of a substantially horizontal central slice of a generally spherical space.
  • central slice is meant to encompass any interior slice of a sphere and is not limited to slices that are centered on or incorporate the center of the sphere.
  • an inter-heliostat collision sphere mapped about by the motion of the reflector structure is effectively truncated at two opposing sides of the heliostats, and for fixed vertical axis heliostats a collision sphere is effectively truncated at top and bottom surfaces.
  • Such fixed horizontal axis heliostats may be packed relatively close together side-to-side (e.g., in rows) without the need for collision avoidance systems, but inter-row collisions may still be possible.
  • the reflector structure of the heliostats described here may be coupled to an upper (distal) end of a vertically extending structure via the linkage to allow for rotation about the first and second rotational axes.
  • the linkage may comprise two rotational elements, where a first rotational element allows the reflector structure to be pivoted around the first rotational axis, and a second rotational element allows the reflector structure to be pivoted around the second rotational axis.
  • the first and second rotational elements may have any suitable structure.
  • at least one of the first and second rotational elements may comprise one or more bearings, axles, gears, pivots, wheels, or combinations thereof.
  • the first and second rotational elements may in some variations be separate elements, e.g., the first rotational element may comprise a first bearing or first set of bearings, and the second rotational element may comprise a second bearing or a second set of bearings.
  • the first and second rotational elements may be part of a unitary element, e.g., a joint configured to allow rotation about two orthogonal axes.
  • the linkage between the reflector structure and the vertically extending support member may comprise one or more arms or other structural members that couple the reflector structure to a rotational element that is coupled to the vertically extending structure.
  • the linkage may comprise a carrier-mounting member, where the carrier-mounting member is coupled to the vertically extending support member via a first rotational element that allows rotation about a fixed horizontal axis. The carrier member may then be coupled to a carrier that is configured to support a reflector element via a second rotational element.
  • the first and second actuators are configured to rotate the reflector about the first and second rotational axes, respectively.
  • the first actuator is configured to apply force along a first actuator axis to rotate the reflector structure about the first rotational axis
  • the second actuator is configured to apply force along a second actuator axis to rotate the reflector structure about the second rotational axis.
  • neither the first nor the second actuator axes is parallel to the first or the second rotational axis. Any suitable type of actuator may be used in the heliostats described here.
  • geared drives e.g., electrically energized, pneumatically activated actuators, hydraulically energized, or any combination thereof may be used.
  • a series of electrical pulses may be applied to an actuator comprising a stepper motor to effect extension and retraction of the actuator.
  • the first and second actuators in a single heliostat may be identical or different.
  • any suitable type of reflector element may be used in the heliostats described here.
  • reflector elements in some variations may comprise a glass mirror that is coupled to the carrier (e.g., adhered to the carrier).
  • Reflector elements may have any suitable shape, e.g., rectangular, elongated, polyhedral, and the like.
  • Reflector elements may comprise a reflective surface (e.g., a mirror surface) that is flat, or curved.
  • various ones of the heliostats within a heliostat field may be provided with flat or concave reflector elements, depending upon the intended positions within the field of the respective heliostats.
  • near and far field heliostats may be provided with concave reflector elements and mid-field heliostats may be provided with flat reflector elements.
  • heliostat 1 comprises a reflector structure 11 that is supported by a ground-mounted or ground-anchored vertically extending support member 10.
  • vertically extending support members may comprise a tubular or generally cylindrical post or pedestal.
  • a vertically extending support member may comprise multiple posts or pedestals.
  • some vertically extending support members may comprise two, three or more angled struts.
  • the vertically extending support member may have any suitable dimensions, e.g., about Im to about 5m, e.g., about 3m or about 2m, e.g., about 1.75m.
  • Reflector structure 11 in turn, comprises a reflector element 18 and a carrier 17 that is configured to support the reflector element 18.
  • the reflector structure 11 is coupled to the vertically extending support member 10 so that the reflector structure 11 (and hence the reflector element 18) can be rotated about a first rotational axis, and independently about a second axis that is substantially orthogonal to the first axis, to reflect incident solar radiation to at least one tower-mounted receiver (not shown).
  • the heliostat shown in FIGS.
  • the first rotational axis 14 is located near an upper (distal) end 110 of the vertically extending support member 10.
  • the second rotational axis 28 may be generally parallel to a longitudinal axis 147 of the reflector structure 11.
  • the first rotational axis may be "fixed" relative to the
  • the first rotational axis is a fixed horizontal axis.
  • the heliostats described here comprise a linkage between the vertically extending support member and the reflector structure.
  • the linkage may comprise a first rotational element configured for rotation about the first rotational axis, and a second rotational element configured for rotation about the second rotational axis.
  • heliostat 1 comprises a linkage 148 that comprises a first rotational element 144 that is configured to allow rotation of reflector structure 11 around the first rotational axis 14, which in this case is a fixed horizontal axis.
  • the distal end 110 of vertically extending support member 10 may comprise a platform 12 configured to support the first rotational element 144.
  • the first rotational element 144 may have any suitable structure, e.g., one or more pivots, bearings, axles, gears, wheels, or the like.
  • the first rotational element 144 may comprise one or more bearings 13 (e.g., two or more spaced-apart self-aligning bearings 13, where the first (horizontal) rotational axis 14 extends through the spaced-apart bearings).
  • Platform 12, if present, may extend at least partially across the upper end of vertically extending support member 10, and in some variations platform 12 may cap or close an open upper end of vertically extending support member 10.
  • the linkage 148 comprises a second rotational element 145.
  • the second rotational element 145 may have any suitable structure that allows rotation of the reflector structure about the second rotational axis 28 that is substantially orthogonal to the first (horizontal) rotational axis 14.
  • the second rotational element 145 comprises a pivotal connector 21.
  • the second rotational element may have any suitable structure, e.g., a bearing, a gear, a wheel, an axel, or the like.
  • the linkage 148 comprises a carrier-mounting member 15 that is coupled to the vertically extending support member 10 via stub axles 16 that are journalled in the bearings 13.
  • the carrier mounting member 15 is pivotally mounted about the first (horizontal) rotational axis 14.
  • the carrier mounting member 15 supports a carrier 17 that, in turn, carriers a reflector element 18, which may be rectangular.
  • the carrier-mounting member 15 may comprise a pivotal arm 19 (e.g., a channel-shaped pivotal arm) and two spaced-apart downwardly projecting limbs 20 that carry the stub axles 16.
  • the second rotational element 145 that, in this case, comprises pivotal connector 21 is provided adjacent one end of the pivotal arm 19.
  • the pivotal connector 21 is connected to an extensible shaft portion 22 of a first actuator 23.
  • the first actuator 23 may comprise an electrically energized (telescopic) linear actuator that has a fixed body portion 24 connected to the vertically extending support member 10 by way of a clamp or other structure 25 that is pivotally connected to a distal portion 110 of the vertically extending support member 10.
  • the first actuator 23 When energized (e.g., positively and negatively, such as with positive and negative electrical pulses) the first actuator 23 extends and retracts along a first actuator axis 50 to impart counterclockwise and clockwise pivotal movement to the carrier-mounting member 15 relative to the vertically extending support member 10 and about the first (fixed horizontal) axis 14.
  • the first actuator axis may extend in a direction that is not aligned with either of the first and second rotational axes.
  • two lugs 26 are located at opposite ends of the pivotal arm 19 and provide bearings 27 through which the second rotational axis 28 extends.
  • the second rotational axis 28 is orthogonal to and independently pivotable about the first rotational axis 14.
  • the bearings 27 may carry short axles 29 by which the carrier 17 is pivotally mounted about the second axis 28 to the carrier-mounting member 15.
  • a downwardly-projecting limb 30 is located at one end of the pivotal arm 19 and may optionally carry a pivotal connection 31 for a clamp or other structure 32.
  • the clamp or structure 32 functions to provide a pivotal connection between the carrier- mounting member 15 and a second actuator 33.
  • the second actuator 33 may be similar to the first actuator 23.
  • the second actuator may comprise an electrically energized (telescopic) linear actuator that, with positive and negative energization, e.g., positive and negative electrical pulses, extends and retracts along a second actuator axis 51 to impart counterclockwise and clockwise pivotal movement to the carrier 17 about the second axis 28.
  • the second actuator axis may extend in a direction that is not aligned with either the first or second rotational axes, or with the first actuator axis.
  • the first and second actuators employed in the heliostats may be any suitable type of actuators (e.g., electrically driven, pneumatically driven, or hydraulically driven, or linear or nonlinear), and the first and second actuators may be identical or different.
  • FIGS. 7 A to 7D provide rear perspective, front, side, and top views, respectively, of the heliostat 700.
  • the heliostat 700 comprises vertically extending support member 710, a reflector structure 711 that comprises a carrier 717 that is configured to support a reflector element 718, and a linkage 748 coupling the reflector structure 711 to the vertically extending support member 710.
  • the linkage 748 comprises a first rotational element 744 that is configured to allow rotation of reflector structure 711 about a first rotational (fixed horizontal) axis 714.
  • Linkage 748 comprises a second rotational element 745 that is configured to rotate reflector structure 711 about a second rotational axis 728.
  • rotational element 745 comprises pivotal connectors disposed on opposite ends of a carrier- mounting element 715.
  • a first actuator 723 provides force along a first actuator axis 750 to effect clockwise and counterclockwise rotations about the first rotational axis 714
  • a second actuator 733 provides force along a second actuator axis 751 to effect clockwise and counterclockwise rotations about the second rotational axis 728.
  • the first actuator 723 is mounted to vertically extending support member 710, e.g., with a clamp or pivot tab 752, and is coupled at its distal end 755 to the carrier-mounting member 715 at position 753 to rotate the reflector structure 711 about axis 714 as the actuator 723 is extended and retracted.
  • the second actuator 733 is pivotally mounted to the carrier-mounting member 715, e.g., with a clamp or pivot tab 754, and is coupled to the carrier 717 at position 757 to rotate the reflector structure 711 about axis 728 as the actuator 733 is extended and retracted.
  • first rotational axis 714 is a fixed horizontal axis in this variation
  • actuator 723 can rotate the reflector structure 711 to follow elevational (zenith) changes in sun position
  • actuator 733 can rotate the reflector structure 711 to track azimuthal changes in sun position.
  • actuator 733 may alternatively be coupled to the carrier at position 758. In this variation, neither actuator axis is aligned with the first or second rotational axis.
  • FIGS. 8 A to 8E illustrate a variation of a vertically extending support member that may be used with any of the heliostats described here.
  • FIG. 8B is rotated 90° relative to FIG. 8 A
  • FIG. 8C provides an enlarged view of the encircled region A
  • FIG. 8D provides a top view
  • FIG. 8E provides an enlarged view of the encircled region B.
  • Vertically extending support member 810 comprises a post section 808 and a platform 812 disposed on the distal end 840 of member 810.
  • Platform 812 supports a first rotational element 844.
  • the first rotational element comprises two collinear stub axles that define a first rotational (fixed horizontal) axis 814.
  • FIGS. 9 A to 9D illustrate a variation of a carrier-mounting member that may be used with any of the fixed horizontal axis heliostats described here.
  • FIG. 9 A is a perspective view
  • FIG. 9B is a side view
  • FIG. 9C is a top view
  • FIG. 9D is an end view of a carrier-mounting member 915.
  • carrier-mounting member 915 comprises a pivotal arm 919 and two spaced-apart limbs 920 extending normal from the pivotal arm 919.
  • the limbs 920 each comprise an orifice 960 through which an axle or a pair of stub axles (not shown) may extend to define a first rotational axis 914.
  • Bearings 927 are provided on each of two lugs 926 disposed on opposite ends of pivotal arm 919.
  • a second rotational axis 928 extends through bearing 927.
  • a projecting limb 930 is disposed on one end 962 of the pivotal arm 919, and extends normal from the pivotal arm 919.
  • An actuator (not shown) configured for providing azimuthal motion of a reflector structure may be pivotally coupled to an end 961 of the limb 930.
  • An actuator mount 963 is disposed on an opposite end 964 of arm 919 and may be configured to be coupled (e.g., pivotally coupled) to an actuator (not shown) configured for providing elevational motion of a reflector structure (not shown).
  • FIG. 10 provides another variation of a linkage between a vertically extending support member and a reflector structure that may be used with any of the fixed horizontal axis heliostats described here.
  • the vertically extending support member 1010 comprises a top plate 1012 that supports a pair of lugs 1070, each comprising a bearing 1071.
  • the linkage comprises a first rotational element 1044 that comprises coaxial bearings 1071 with an axle 1072 extending through the bearings to define a first rotational (fixed horizontal) axis 1014.
  • the reflector structure 1011 is then structurally linked to rotational element 1044 via carrier-mounting member 1015 that is similar to carrier-mounting member 15 depicted in FIGS. 1 to 6, and carrier- mounting member 915 depicted in FIGS. 9 A to 9D.
  • FIGS. 1 IA and 1 IB illustrate a variation of a heliostat having a fixed vertical pivot axis.
  • FIG. 1 IA provides a perspective view
  • FIG. 1 IB provides a side view.
  • heliostat 69 comprises a ground-mounted or anchored vertically extending support member 40.
  • Vertically extending support member 40 may, for example, be similar to vertically extending support member 10 shown in FIG. 1 or vertically extending support member 810 shown in FIGS. 8A-8E.
  • Heliostat 69 comprises a reflector structure 41 that is coupled to the vertically extending support member 40.
  • the vertically extending support member 40 comprises an internal cavity (e.g., support member 40 may be hollow or tubular) so that a vertical shaft 42 may extend into the support member 40 and be journalled for rotation about a fixed vertical (first rotational) axis 43.
  • the shaft 42 may form a portion of a carrier-mounting member 44 so that the carrier-mounting member 44 is pivotal about the fixed vertical axis 43.
  • the carrier-mounting member 44 supports a carrier 45 that, in turn, carries a reflector element 46.
  • the carrier 45 may be substantially similar to those described above with respect to fixed horizontal axis heliostats.
  • the reflector element 46 may be any suitable reflector element, e.g., flat or curved, such as a cylindrical reflector or a spherical reflector. In some cases, reflector 46 is rectangular.
  • the carrier-mounting member 44 also incorporates a horizontally disposed support bar 47 that may be coupled (e.g., welded) to a distal (upper) end of the shaft 42.
  • the support bar 47 may be rotatable (with the shaft) about the vertical axis 43.
  • Two outwardly projecting lugs 48 may be located at opposite ends of the support bar 47 and may be connected to corresponding lugs 49 on the carrier 45, e.g., by way of pivot pins 50.
  • the pivot pins 50 may be aligned with a second rotational axis (horizontal) 51 that is substantially orthogonal to the first (fixed) vertical axis 43.
  • this coupling arrangement provides for pivoting of the carrier and reflector element about the vertical first (fixed) axis 43.
  • a connector arm 52 projects rearwardly from the support 47 and is coupled by way of a pivotal connector 53 to an extensible shaft portion 54 of a first actuator 55.
  • the first actuator 55 may, for example, comprise an electrically energized (telescopic) linear actuator.
  • the first actuator may have a fixed body portion 56 that is coupled to the support member 40, e.g., by way of a clamp or pivot tab (not shown) that is pivotally connected to a radius arm 57 that projects outwardly from an upper portion of the support member 40.
  • the first actuator 55 can extend and retract to impart counterclockwise and clockwise pivotal movement to the carrier-mounting member 44 relative to the support member 10 and about the first rotational (fixed vertical) axis 43.
  • a second actuator 56 interconnects the connector arm 52 and the carrier 45, again by way of pivotable connectors (not shown).
  • the second actuator 56 can function to effect counterclockwise and clockwise pivoting of the carrier 45 about the second rotational (horizontal) axis 51.
  • the first and second actuators may be any suitable actuators, e.g., electrically energized actuators, which may for example be actuators comprise a stepper motor to extend and retract upon receipt of a series of positive and negative electrical pulses. Further, the first and second actuators in the heliostat 69 may be identical or different.
  • FIGS. 12 and 13 illustrate examples of three-dimensional collision spaces traced out by the rotation of a reflector structure about its first and second rotational axes.
  • the relative placement of adjacent heliostats maybe determined by these three-dimensional collision spaces, or collision volumes.
  • the heliostat when rotated may occupy at least a portion of a vertically oriented central slice of a spherical volume.
  • the collision volume shown corresponds to possible rotation of the reflector structure in a 180 degree arc about the fixed horizontal rotational axis.
  • the collision volume is a correspondingly truncated portion of that shown in FIG.
  • the collision volume shown corresponds to possible rotation of the reflector structure in a 180 degree arc about the fixed vertical rotational axis.
  • the collision volume is a correspondingly truncated portion of that shown in FIG. 13.
  • heliostat 1200 comprises reflector structure 1211 that is coupled to vertically extending support member 1210 via linkage 1248.
  • Linkage 1248 is configured to allow rotation about a first fixed horizontal axis 1214, and independent rotation about a second axis 1228 that is substantially orthogonal to the first horizontal axis 1214.
  • the linkage 1248 comprises a carrier-mounting member 1215 that supports carrier 1217 of reflector structure 1211.
  • Carrier 1217 supports a reflector element (not shown).
  • the first actuator 1223 applies force along a first actuator axis 1250 to rotate the reflector structure 1211 about first horizontal axis 1214
  • the second actuator 1233 applies force along a second actuator axis 1251 to rotate the reflector structure 1211 about second rotational axis 1228.
  • the first actuator axis 1250 is not aligned with the first or second rotational axes
  • the second actuator axis is not aligned with the first or second rotational axes.
  • the collision space 1252 is truncated along the sides 1253 to form relatively planar vertical sides, close adjacent packing (e.g., within a row) of these heliostats is possible, e.g., a distance between outer edges of adjacent heliostats of less than about 6 inches, within less than about 5 inches, within less than about 4 inches, within less than about 3 inches, within less than about 2 inches, within less than about 1 inch, or even closer. There may still be collisions possible between rows of such fixed horizontal axis heliostats.
  • heliostat 1300 comprises reflector structure 1311 that is coupled to vertically extending support member 1310 via linkage 1348.
  • Linkage 1348 is configured to allow rotation about a first fixed vertical axis 1314, and rotation about a second axis 1328 that is substantially orthogonal to the first vertical axis 1314.
  • the linkage 1348 comprises a carrier-mounting member 1315 (similar to carrier mounting member 44 in FIGS. 1 IA and 1 IB) that supports carrier 1317 of reflector structure 1311.
  • Carrier 1317 supports a reflector element (not shown).
  • the first actuator 1323 applies force along a first actuator axis 1350 to rotate the reflector structure 1311 about first vertical axis 1314
  • the second actuator 1333 applies force along a second actuator axis 1351 to rotate the reflector structure 1311 about second rotational axis 1328.
  • the first actuator axis 1350 is not aligned with the first or second rotational axes
  • the second actuator axis is not aligned with the first or second rotational axes.
  • Heliostats similar to heliostats 1200 and 1300 may be employed in multi-tower solar arrays.
  • Multi-tower solar arrays may comprise target receivers located at opposite ends of a heliostat field.
  • the heliostat variations illustrated in FIGS. 12 and 13 may configured to be rotated over a range of angles corresponding for example, to about a 90° arc, about a 120° arc, or about a 150° arc of the collision space to track diurnal motion of the sun, and to direct incident radiation to a target receiver, hi some cases, one or more heliostats in an area may be configured to change the target receiver to which it is directing incident radiation.
  • FIG. 14 illustrates a variation of a reflector structure 1411 that may be used in any of the heliostats described here.
  • the carrier 1417 comprises a skeletal frame, which may be rectangular, having longitudinally extending frame portions 1434 and transverse ribs 1435.
  • the carrier 1417 has dimensions between about Im and about 3m, e.g., about 2m x about 2m, , about 2m x about 3m, about Im x about 2m, about 1.5m x about 2.5m, or about 1.8m x about 2.4m.
  • the carrier 1417 supports the reflector element 1418. As illustrated in an exaggerated way in FIG. 14, the longitudinally extending frame portions and the ribs may be curved.
  • FIG. 14 illustrates a variation of a reflector structure in which the longitudinal frame portions and ribs are curved orthogonally to each other, e.g., to form a spherical reflector element or mirror, other reflector structures may be used with the heliostats described here.
  • cylindrical reflector elements or flat (planar) reflector elements may be used.
  • curved reflector elements e.g., spherical or cylindrical
  • a radius of curvature within the range of for example about 40m to about 80m may be used. The actual or approximate radius of in any given situation may be dependent upon the distance that the heliostat is to be located from a target receiver.
  • Reflector elements used in reflector structures may comprise any suitable material.
  • reflector elements may comprise polished metal, or a glass mirror having a rear silvered surface. If present, a silvered surface may be coated or otherwise treated with a protective layer to reduce possible weathering effects.
  • Glass mirrors, when employed, may typically have a thickness of about 0.001m to about 0.005m, e.g., on the order of about 0.003m.
  • the reflector elements may be bonded to a carrier to form a reflector structure for use in the heliostats described here. Any suitable method may be used to bond reflector elements to carriers.
  • a reflector element may be secured to a carrier by bonding the rear face of a reflector element to the skeletal members of the carrier with an adhesive, e.g., a urethane adhesive, and the reflector element may be formed with a concavity that conforms with the curvatures (e.g., orthogonal or cylindrical) of the carrier by loading the reflector element against the carrier during the time that the adhesive takes to set and cure.
  • an adhesive e.g., a urethane adhesive
  • a reflector element 1518 maybe pressed against a former 1573 having a curved molding surface 1574.
  • the curvature of the molding surface 1574 may be selected to mirror the desired curvature of the reflector element 1518.
  • the desired reflector element is a cylindrical concave reflector having a radius of curvature such that the reflector ends are offset -2.5mm from a center of the reflector element
  • former 1573 can be made (e.g., machined) to have a curved convex molding surface 1573 with ends offset +2.5mm from a center to be aligned with the reflector element's center.
  • a mirror e.g., a glass panel
  • a flat carrier 1517 (which may be a steel carrier) may have adhesive 1577 placed on a surface to be bonded to the mirror. Any suitable type and application of adhesive may be used, e.g., polyurethane adhesive may be applied as beads to the bonding surface of the carrier. The adhesive-applied surface of the carrier 1517 maybe placed over the mirror 1518 pressed against the former 1573.
  • Pins 1575 coupled to a support frame 1576 may be used to align the mirror with the former, and to fix the height of the carrier above the mirror so that the adhesive when cured fixes the gap between the mirror and the carrier to set the desired curvature of the mirror.
  • FIGS. 16A and 16B An alternative method for imparting curvature to a reflector element is illustrated in FIGS. 16A and 16B.
  • a carrier 1617 is manufactured to have a predetermined radius of curvature, e.g., a spherical concave radius or a cylindrical concave radius.
  • the curved carrier 1617 may be supported from beneath, e.g., with adjustable support stands 1678.
  • a mirror 1618 may be pressed face up against the curved carrier 1617 with an adhesive (e.g., a urethane-based adhesive) interspersed between the mirror and the carrier. Force may be applied directly to the mirror (e.g., with weights such as sand bags) to press the mirror against the curved carrier.
  • an adhesive e.g., a urethane-based adhesive
  • an interface board 1679 e.g., a caul board
  • weights or force may be placed against the interface board to force the mirror against the curved carrier.
  • the interface board e.g., caul board
  • the interface board may function to distribute applied force over a surface area of the mirror.
  • an interface board may be used that distributes applied force over a majority of the surface area of the mirror, e.g., greater than about 60%, or greater than about 80% of the mirror's surface area.
  • FIGS. 17A and 17B Examples of solar energy collector arrays are shown diagrammatically in FIGS. 17A and 17B.
  • FIG. 17A provides a diagrammatic representation of an example of a solar energy collector system having a generally rectangular field of heliostats and two target receivers
  • FIG. 17B is a diagrammatic representation of another example of a solar energy collector system having two contiguous, generally rectangular fields of heliostats, each of which has a single target receiver.
  • the first and second actuators e.g., actuators 23 and 33 of fixed horizontal axis heliostat 1 shown in FIGS. 1 to 6 or actuators 55 and 56 of fixed vertical axis heliostat 69 shown in FIGS. 1 IA and 1 IB
  • a computer-driven processor 65 to provide for track diurnal movement of the sun, as illustrated diagrammatically in FIG. 18.
  • the first and second actuators e.g., first and second actuators 23 and 33 of heliostat 1 in FIGS. 1 to 6 or first and second actuators 55 and 56 of heliostat 69 in FIGS. 1 IA and 1 IB
  • positioning the reflector elements are actuated in a manner that is controlled to provide for substantially constant path angle of reflection from the heliostats with changes in azimuthal and elevational angle of the sun.
  • a selected heliostat (or a group of heliostats) is required to reorientate, for example to shift the direction of reflected radiation from one target receiver 64 to another
  • at least one of the first and second actuators of the relevant heliostats is actuated in a manner that is controlled to effect the reorientation.
  • the term "reflector” is meant to encompass a reflector structure (e.g., a structure comprising a carrier supporting a reflector element) and/or a reflector element (e.g., a mirror) of a heliostat.
  • a reflector structure e.g., a structure comprising a carrier supporting a reflector element
  • a reflector element e.g., a mirror
  • position or movement is meant to encompass position or movement of a reflector, i.e., a reflector structure, a reflector structure and a reflector element, or a reflector element.
  • the collision detection systems, collision avoidance systems and related methods described here utilize a simulated three-dimensional shape to represent a reflector, herein referred to as a reflector representation.
  • the reflector representations are numerical representations, and in some cases they may be graphically displayed.
  • An array, or a portion of an array may be simulated by creating a reflector representation for each reflector in that array or array portion, and arranging a set of reflector representations using positional data of reflectors in the array. Movements of the reflectors in the array may be simulated by numerically moving the reflector representations in the simulated array.
  • a reflector representation may represent its corresponding reflector to scale, or a reflector representation may be adjusted relative to the actual reflector.
  • one or more dimensions of a reflector representation may be changed relative to a reflector, e.g., by a multiplicative factor and/or by an offset.
  • at least one dimension of a reflector representation may be enlarged by at least about 1%, at least about 2%, at least about 5%, at least about 8%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, or at least about 30% relative to the actual scale of its corresponding reflector.
  • Such adjustments may be used in the collision avoidance methods and systems to adjust a margin for error and/or a time lag between a predicted collision and an actual physical collision.
  • each reflector representation can be confined to a calculated three-dimensional space (a calculated collision volume) analogous to, but not necessarily the same as, the three-dimensional space (actual collision volume) which movement of its corresponding reflector is confined.
  • volume 1252 may correspond to the actual collision volume for the reflector structure associated with heliostat 1200
  • volume 1352 may correspond to the actual collision volume for the reflector structure associated with heliostat 1300.
  • a calculated or simulated collision volume for a reflector representation may be calculated using dimensional data of its corresponding reflector, e.g., the width, height, and thickness of the reflector, and simulating movement of the reflector over its possible range of motion.
  • a simulated collision volume may be adjusted to be slightly larger than that corresponding to the physical dimensions of a reflector, e.g., by using a multiplicative factor (a percent), or by enlarging at least one dimension of the reflector representation relative to the actual scale of the reflector it represents.
  • a potential collision may occur when there is an intersection between any two collision volumes in a solar array. For example, potential collisions may be detected between adjacent ones of heliostats within a row, or between adjacent ones of heliostats between rows.
  • a solar energy collector array 200 comprises at least two heliostats 202 and 204.
  • Heliostat 202 comprises a first reflector structure 206 supported by a vertically extending support member 210
  • heliostat 204 comprises a second reflector structure 208 supported by a vertically extending-support member 212.
  • both heliostats 202 and 204 are fixed vertical axis heliostats, similar to those illustrated in FIGS. 1 IA and 1 IB and FIG. 13.
  • the intersection 214 in this illustrates indicates a potential collision.
  • the simulated array and the concept of a simulated collision volume for each simulated reflector representation may be used to predict, and hence to prevent, a physical collision between two reflectors. For example, if a reflector representation in a simulated array has one or more of its dimensions enlarged relative to its corresponding physical reflector, then the oversized reflector representation may collide with another reflector representation in the simulated array before such collision would occur in the physical array. Thus, oversizing one or more dimensions of a reflector representation relative to the physical reflector is one approach that may be used to predict a potential collision.
  • Some arrays may comprise one or more regions of close packed heliostats that may be susceptible to collisions, and one or more regions of heliostats that may not be susceptible to collisions. In those arrays, it may not be necessary to simulate the entire array, but only that part of the array for which collisions are a concern. For example, some arrays may utilize a collision detection system in connection with fixed vertical axis heliostats and may not use a collision detection system in connection with fixed horizontal axis heliostats, such as those illustrated in FIG. 12, that may be close paced without increasing the risk of inter-heliostat collision.
  • a variety of collision avoidance methods and systems may be derived using the collision detection method described above.
  • One variation of a method is illustrated in flow chart form in FIG. 20.
  • Dimensional data for each reflector is stored (300). Such dimensional data may include, for example, the width, height and thickness of the reflector. As stated above, the dimensional data may reflect scale dimensions, or may be different than scale dimensions (e.g., one or more dimensions may be slightly enlarged).
  • a three-dimensional numerical reflector representation is created for each reflector (302).
  • These methods include obtaining three dimensional positional data for each reflector, and storing that positional data in connection with the reflector representation associated with that reflector (304).
  • the positional data may include for example azimuthal angle and/or zenith angle, and may in some cases be stored as three- dimensional coordinates, e.g., (x, y, z).
  • the positional data for each reflector may be obtained in any suitable manner, but in some variations, the positional data for a reflector may be discerned from one or more actuators in the heliostat that are used to position that reflector. For example, if one or more linear actuators is used to position a reflector, the extensional position of the one or more linear actuators may be used to determine the position of that reflector.
  • the positional data for the reflector structure 18 may be determined from the extensional positions of linear actuators 23 and 33.
  • the positional data may be adjusted (e.g., scaled, offset, or the like) relative to actual scale.
  • An array, or at least a portion of an array may then be simulated using the reflector representations, including their associated positional data (304).
  • at least a portion of a simulated array may be graphically represented (306) e.g., to a display.
  • the positional data for each reflector may be periodically or continuously updated and stored in connection with its associated reflector representation (308).
  • the updating of the positional data may occur at any rate, e.g., each reflector representation may have its positional data updated about every 5 seconds, about every 4 seconds, about every 3 seconds, about every 2 seconds, about every second, or even more often, e.g., about every 0.5 seconds.
  • the methods may comprise updating the position of a heliostat in substantially real-time, e.g., with a lag time of less than about 5 seconds, less than about 2 second, less than about 1 second, or less than about 0.5 seconds.
  • the methods can then include monitoring the simulated array for any intersection between any two reflector representations (312), e.g., between the reflector representations for adjacent reflectors within a row, or between reflector representations for reflectors in different rows. If there is an intersection between reflector representations detected in the simulation (312), then a potential collision is detected (310). If a potential collision is detected, the methods may optionally include automatically and/or manually controlling one or more reflectors in an array prevent a collision (320) (not shown). Automatic and manual responses to potential collisions are described in more detail below. It should be pointed out that in these methods, the movement of reflectors may occur in parallel or in sequence. That is, the methods may include moving one reflector at a time, or may include moving more than one reflector at a time.
  • At least one of the reflector representations in a simulated array may be oversized in at least one dimension so that a simulated collision occurs before a physical collision.
  • the amount of oversizing in one or more dimensions may be adjusted to adjust the error for margin desired for potential collisions and/or to adjust the time lag between a simulated collision and a physical collision. For example, if only a short time lag is desired between a predicted collision and an actual collision, a relatively small amount of oversizing may suffice. If a longer time lag is desired between a predicted collision and an actual collision, a larger amount of oversizing in one or more dimensions may be used. If a larger margin for error in predicting potential collisions is desired, a relatively large amount of oversizing may be used.
  • FIG. 21 One such variation of a collision detection method is illustrated in flow chart form in FIG. 21.
  • a desired movement for one or more reflectors may be simulated and evaluated for collision potential before initiating or completing that movement.
  • the steps 400, 402, 404, and 406 are analogous to the steps 300, 302, 304, and 306 described in connection with FIG. 20.
  • a desired movement of one or more reflectors may be simulated (414).
  • the desired movement may be determined in any suitable manner, and may for example be calculated based on a known path of the sun and a time of day.
  • a desired movement for a reflector may be a move to a park or stow position. If the simulated reflector movement results in any intersection between reflector representations (412), then a potential collision is detected (410). If a potential collision is detected, then the methods may include automatically and/or manually controlling one or more reflectors to prevent a collision (420) (not shown). Possible manual and automatic responses to potential collisions are described in more detail below. If there is no intersection between numerical reflector representations, the desired movement of the reflector may be completed (416), and the positional data of one or more reflectors may be updated and stored in connection with the reflector representation associated with each reflector (408). It should be pointed out that while a potential movement of a reflector is being evaluated for potential for causing a collision as described here, the other reflectors in the array may be static or moving.
  • the methods for detecting potential collisions as described here may be incorporated into methods for automatically positioning reflectors, e.g., to track the. position of the sun and to reflect incident radiation to a desired target and/or to stow or park a reflector.
  • reflector positioning methods may comprise delivering movement instructions to a group of reflectors, collecting positional data from the group of reflectors, and feeding this positional data into a collision avoidance algorithm, such as those described in connection with FIGS. 20 and 21.
  • the methods for positioning a heliostat reflector comprise determining a desired reflector position. For example, if the reflector is being moved to track the sun, the desired reflector position may be based on the position of the sun and the position of a target receiver.
  • the methods described here comprise converting the desired three-dimensional reflector position to first and second displacements, and moving the reflector to the desired position by translating a first linear actuator by the first displacement, and translating the second linear actuator by the second displacement.
  • the first linear actuator may be configured to change an azimuthal angle of the reflector
  • the second linear actuator may be configured to change an elevational (zenith) angle of the reflector.
  • FIG. 22 One example of a method for tracking the position of a reflector structure in a heliostat is illustrated in FIG. 22.
  • a "tracking heliostat" is a heliostat that is configured to move its reflector structure to track the motion of the sun and to reflect incident solar radiation to a selected target (502).
  • a selected target 502
  • FIGS. 23A to 23B an example of a reflector and its associated actuators is provided in FIGS. 23A to 23B.
  • the latitude and longitude of the base of the target receiver may be stored.
  • a three-dimensional reflector position relative to the target receiver in an (x, y, z) coordinate space may also be stored.
  • reflector 618 is coupled to vertically extending member 610 via a linkage 648.
  • a first actuator 623 is configured to position the reflector elevationally (along a zenith), and a second actuator 633 is configured to position the reflector 618 azimuthally.
  • the geometrical parameters a, b, c, and e correspond to distances, and ⁇ Off corresponds to the initial angle of an actuator relative to the plane of the reflector. For example, ⁇ Off as illustrated in FIG. 23 A is 90°.
  • extensional positions of the actuators may correspond to a pulse count.
  • an extensional position of the actuator can be determined using the number of electrical pulses that have been delivered to the actuator and a factor indicating displacement per electrical pulse.
  • the extensional position of an actuator may be indicated herein as a "pulse count” or "pulse location.”
  • desired azimuth and zenith angles may be calculated for each tracking heliostat (504). To calculate these desired angles, a vector from the sun to the heliostat, and a vector from the heliostat to a desired target receiver may be determined. Vector algebra may then be used to calculate the desired zenith and azimuth angles of the heliostat to direct incident solar radiation to the target. After the desired azimuth and zenith angles have been determined, the angles can be translated into desired actuator extensional positions. For linear actuators incorporating a stepper drive, a pulse count corresponding to the desired extensional position for each actuator may be determined.
  • Geometrical parameters can be used to convert the desired angles into desired pulse counts or pulse locations for the actuators (506). Any suitable set of geometrical parameters may be used, e.g., distances and/or angles.
  • the geometrical parameter set comprising distances a, b, c, e, and the angle ⁇ 0f r as shown in FIGS. 23A to 23B may be used to convert a desired angle (e.g., azimuth or zenith) into a desired pulse location for the actuator configured to change that angle. If the desired pulse count is different than the existing pulse count for an actuator (508), instructions may be sent to that actuator to move to the desired pulse count location (510).
  • Instructions may be sent to and data received from an actuator using any appropriate interface, which may be a wireless or hard- wired interface.
  • an RS 485 communications link may be used to interface a heliostat with a control system (e.g., similar to controller 67 as illustrated in FIG. 18).
  • a function that depends on the geometric parameters may be derived to convert a desired three-dimensional position, e.g., an azimuthal angle and a zenith angle, to two linear displacements.
  • each heliostat may be calibrated at various times throughout a day or other time period to compensate for misalignment, cumulative numerical errors, and the like.
  • the geometrical parameters that allow for conversion of linear actuator displacement to reflector position may be re-determined, and stored for use in future movement of the reflector structure.
  • a function 2301 represents the dependence of a reflector angle (e.g., an azimuthal or zenith angle) on pulse count, which corresponds to a displacement of the linear actuator configured to change the angle.
  • the function 2301 is not linear.
  • a set of calibration points 2300 may be collected over a range of angles (e.g., azimuthal and/or zenith angles).
  • Curve fitting e.g., heuristic curve fitting, may be used to generate curve 2301 that depends on geometrical parameters (e.g., a, b, c, e, and ⁇ Of r in FIGS. 23 A and 23B).
  • the optimal values of these geometric parameters determined by fitting curve 2301 to calibration points 2300 may then be stored and used for future reflector movements, as described above.
  • the type and magnitude of the geometric parameters may be different for different actuators in a heliostat. For example, a different set of dimensions and/or angles may be used to describe the dependence of angle on linear displacement for each of the actuators in a heliostat.
  • the methods described here to move the position of a heliostat may be applied to determine or track the position of a heliostat. That is, by obtaining linear displacements of the first and second linear actuators driving a reflector, relative to known reference points, the position of that reflector may be determined.
  • the same conversion function used to convert three-dimensional positional data to two linear displacements may be used in reverse to convert two linear displacements to three-dimensional positional data.
  • the methods may allow precise determination of the position of a reflector structure, e.g., less than about lmm, less than about 0.5mm, or less than about 0.1mm. In some variations, the precision achieved may be improved by fitting the conversion function to a set of calibration points as shown in FIG.
  • the collision avoidance system may respond in any one of, or a combination of, several automatic and/or manual modes.
  • movement of at least one reflector implicated in a potential collision may be terminated (e.g., automatically) upon detection of the potential collision, and/or a warning may be sent to a user interface so that the user may evaluate the potential collision make a decision as to how to proceed.
  • a manual override may be implemented by a controller 67 temporarily to effect manual control or actuation of the reflector structure of at least one of two heliostats implicated in a potential collision in a manner to avoid colliding.
  • a collision avoidance control system might be automatically or manually activated to effect movement of a first of two reflector structures temporarily to a park position that avoids collision, and after moving the second reflector structure to its required position, then moving the first reflector structure from the park position to its required position.
  • a collision avoidance control system might be activated to automatically or manually delay movement of one of the two reflector structures until the other reflector structure has been moved beyond a potential collision point.
  • any of the methods described here may be used in combination with other methods described here, now known, or later developed. Further any of the methods may be encoded by a computer program, and computer-executable instructions for carrying out the methods may be stored on a computer-readable medium. Control systems, such as that illustrated in FIG. 18, may be adapted to carry out any of the methods described here.
  • the solar energy collector arrays described here may comprise any arrangement and/or combination of heliostats.
  • the heliostats may be arrayed in parallel east-west extending linear rows, or they may be located in curved rows, e.g., along an arc or loop, or in a spiral path.
  • the spacing between the rows of heliostats may be increased with increasing distance of the rows from a target receiver.
  • Any combination of horizontal fixed axis heliostats, and vertical fixed axis heliostats may be used in the arrays.
  • a collision avoidance system may be used in a solar energy collector array comprising fixed vertical axis heliostats, fixed horizontal axis heliostats, or a combination thereof.
  • the collision avoidance systems described here may be particularly useful for arrays incorporating fixed vertical axis arrays.
  • the potential for intra-row collisions for fixed horizontal heliostats may be ameliorated by the use of the variations of fixed horizontal axis heliostats described here, but the potential for inter-row collisions remains even for these heliostats.
  • the heliostat field may optionally have a generally rectangular or generally circular or oval perimeter and, in the southern hemisphere, a single target receiver may normally be positioned at or near the northern end of the field, either outside or within the boundary of the field.
  • target receivers may be located at opposite ends of the field.
  • a target receiver may be positioned within or adjacent each field.
  • the potential for shading of one heliostat by another heliostat may be alleviated as and when required by reorienting selected heliostats in one field to reflect incident solar radiation to a target receiver that normally is associated with another field.
  • the boundaries and/or shapes of heliostat fields e.g., contiguous heliostat fields, may effectively be changed, or change over time.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Mounting And Adjusting Of Optical Elements (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

La présente invention concerne des variantes de réseaux de capteurs solaires à héliostats. L'invention concerne également des procédés permettant de prédire et d'éviter les collisions entre réflecteurs des héliostats dans un réseau de capteurs solaires. Le réseau comprend des héliostats pourvus de réflecteurs tournant autour de deux axes sensiblement perpendiculaires entre eux. La rotation autour de chacun des axes est commandée par un actionneur pour chaque axe. Le déplacement d'un réflecteur est confiné dans un volume de collision tridimensionnel. Les procédés de détection et d'évitement des collisions consistent à simuler un réseau en créant des représentations tridimensionnelles de réflecteurs correspondant aux réflecteurs du réseau, et à détecter une éventuelle collision en réalisant l'intersection de chaque couple de représentations de réflecteurs dans le réseau simulé.
PCT/AU2008/000096 2007-01-29 2008-01-29 Ferme solaire à dispositif anticollision WO2008092195A1 (fr)

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AU2007900390 2007-01-29
AU2007900390A AU2007900390A0 (en) 2007-01-29 Solar energy collector field incorporating collision avoidance

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US7765705B2 (en) 2008-06-03 2010-08-03 Areva Solar, Inc. Methods and devices for characterizing a surface
US7810940B2 (en) 2008-06-03 2010-10-12 Areva Solar, Inc. Adjustable table for shaping a mirror
DE102010034986A1 (de) 2010-08-20 2012-02-23 Philipp Schramek Solares Zentralreceiversystem mit einem Heliostatenfeld
WO2012083383A1 (fr) * 2010-12-22 2012-06-28 Commonwealth Scientific And Industrial Research Organisation Etalonnage et commande d'héliostat
ITMI20110241A1 (it) * 2011-02-18 2012-08-19 Integra Renewable En Srl Impianto di conversione di energia solare con inseguitore solare perfezionato.
US8277592B2 (en) 2009-03-27 2012-10-02 Areva Solar, Inc. Method of shaping a reflector
EP2546975A1 (fr) * 2010-04-02 2013-01-16 Jianzhong Liu Dispositif de poursuite automatique du soleil
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ITRM20110635A1 (it) * 2011-11-30 2013-05-31 Shap Technology Corp Ltd Eliostato a focalizzazione ottimizzata
WO2012167776A3 (fr) * 2011-06-08 2013-08-15 Schletter Gmbh Support pour modules photovoltaïques
CN103257654A (zh) * 2012-02-17 2013-08-21 海德堡印刷机械股份公司 用于使用在用于利用太阳能的系统中的装置
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US9249785B2 (en) 2012-01-31 2016-02-02 Brightsource Industries (Isreal) Ltd. Method and system for operating a solar steam system during reduced-insolation events
WO2016089875A1 (fr) * 2014-12-01 2016-06-09 Wts Llc Dispositif de suivi à axe double
WO2016089885A1 (fr) * 2014-12-01 2016-06-09 Wts Llc Système de chauffage de fluide
WO2019230150A1 (fr) * 2018-05-31 2019-12-05 株式会社ＳｏｌａｒＦｌａｍｅ Dispositif d'héliostat
US10989420B2 (en) 2016-11-18 2021-04-27 Wts Llc Digital fluid heating system
JP7217567B1 (ja) * 2022-11-16 2023-02-03 株式会社Ｑｄジャパン 太陽追尾装置
US11946886B2 (en) 2014-12-01 2024-04-02 Wts Llc Fluid heating system

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Cited By (48)

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Publication number Priority date Publication date Assignee Title
US8739512B2 (en) 2007-06-06 2014-06-03 Areva Solar, Inc. Combined cycle power plant
US8378280B2 (en) 2007-06-06 2013-02-19 Areva Solar, Inc. Integrated solar energy receiver-storage unit
US8544272B2 (en) 2007-06-11 2013-10-01 Brightsource Industries (Israel) Ltd. Solar receiver
US9022020B2 (en) 2007-08-27 2015-05-05 Areva Solar, Inc. Linear Fresnel solar arrays and drives therefor
US8807128B2 (en) 2007-08-27 2014-08-19 Areva Solar, Inc. Linear fresnel solar arrays
US8360051B2 (en) 2007-11-12 2013-01-29 Brightsource Industries (Israel) Ltd. Solar receiver with energy flux measurement and control
US10041700B1 (en) 2007-11-26 2018-08-07 Esolar, Inc. Heliostat array layouts for multi-tower central receiver solar power plants
US8656907B2 (en) 2007-11-26 2014-02-25 Esolar, Inc. Heliostat array layouts for multi-tower central receiver solar power plants
US8739775B2 (en) 2008-02-14 2014-06-03 Brightsource Industries (Israel) Ltd. Devices, methods, and systems for control of heliostats
US7765705B2 (en) 2008-06-03 2010-08-03 Areva Solar, Inc. Methods and devices for characterizing a surface
US7810940B2 (en) 2008-06-03 2010-10-12 Areva Solar, Inc. Adjustable table for shaping a mirror
US8931475B2 (en) 2008-07-10 2015-01-13 Brightsource Industries (Israel) Ltd. Systems and methods for control of a solar power tower using infrared thermography
WO2010022027A3 (fr) * 2008-08-18 2010-06-17 Pratt & Whitney Rocketdyne, Inc. Joint d’héliostat
WO2010022027A2 (fr) * 2008-08-18 2010-02-25 Pratt & Whitney Rocketdyne, Inc. Joint d’héliostat
US8277592B2 (en) 2009-03-27 2012-10-02 Areva Solar, Inc. Method of shaping a reflector
US9003795B2 (en) 2009-11-24 2015-04-14 Brightsource Industries (Israel) Ltd. Method and apparatus for operating a solar steam system
US9170033B2 (en) 2010-01-20 2015-10-27 Brightsource Industries (Israel) Ltd. Method and apparatus for operating a solar energy system to account for cloud shading
EP2546975A1 (fr) * 2010-04-02 2013-01-16 Jianzhong Liu Dispositif de poursuite automatique du soleil
EP2546975A4 (fr) * 2010-04-02 2013-11-06 Jianzhong Liu Dispositif de poursuite automatique du soleil
AU2011235479B2 (en) * 2010-04-02 2014-08-21 Jianzhong Liu Automatic sunlight-tracking device
WO2012022418A2 (fr) 2010-08-20 2012-02-23 Philipp Schramek Système de récepteur central solaire comportant un champ d'héliostats
DE102010034986A1 (de) 2010-08-20 2012-02-23 Philipp Schramek Solares Zentralreceiversystem mit einem Heliostatenfeld
US9097438B2 (en) 2010-08-20 2015-08-04 Philipp Schramek Central receiver solar system comprising a heliostat field
WO2012083383A1 (fr) * 2010-12-22 2012-06-28 Commonwealth Scientific And Industrial Research Organisation Etalonnage et commande d'héliostat
EP2489961A1 (fr) * 2011-02-18 2012-08-22 Integra Renewable Energies S.r.l. Système de conversion d'énergie solaire avec suiveur solaire
ITMI20110241A1 (it) * 2011-02-18 2012-08-19 Integra Renewable En Srl Impianto di conversione di energia solare con inseguitore solare perfezionato.
WO2012167776A3 (fr) * 2011-06-08 2013-08-15 Schletter Gmbh Support pour modules photovoltaïques
ITRM20110635A1 (it) * 2011-11-30 2013-05-31 Shap Technology Corp Ltd Eliostato a focalizzazione ottimizzata
US9222702B2 (en) 2011-12-01 2015-12-29 Brightsource Industries (Israel) Ltd. Systems and methods for control and calibration of a solar power tower system
US9249785B2 (en) 2012-01-31 2016-02-02 Brightsource Industries (Isreal) Ltd. Method and system for operating a solar steam system during reduced-insolation events
CN103257654A (zh) * 2012-02-17 2013-08-21 海德堡印刷机械股份公司 用于使用在用于利用太阳能的系统中的装置
DE102012021106A1 (de) 2012-02-17 2013-08-22 Heidelberger Druckmaschinen Ag Vorrichtung für den Einsatz in Systemen zur Nutzung von Solarenergie
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WO2016089875A1 (fr) * 2014-12-01 2016-06-09 Wts Llc Dispositif de suivi à axe double
CN107429945A (zh) * 2014-12-01 2017-12-01 Wts有限公司 双轴追踪装置
WO2016089885A1 (fr) * 2014-12-01 2016-06-09 Wts Llc Système de chauffage de fluide
US10168412B2 (en) 2014-12-01 2019-01-01 Wts Llc Dual axis tracking device
US10495720B2 (en) 2014-12-01 2019-12-03 Wts Llc Control valve assembly for a fluid heating system
US11946886B2 (en) 2014-12-01 2024-04-02 Wts Llc Fluid heating system
CN107250687A (zh) * 2014-12-01 2017-10-13 Wts有限公司 流体加热系统
US10890645B2 (en) 2014-12-01 2021-01-12 Wts Llc Dual axis tracking method
US10989420B2 (en) 2016-11-18 2021-04-27 Wts Llc Digital fluid heating system
US11920801B2 (en) 2016-11-18 2024-03-05 Wts Llc Digital fluid heating system
JP2019213276A (ja) * 2018-05-31 2019-12-12 株式会社ＳｏｌａｒＦｌａｍｅ 太陽追尾装置
US11387773B2 (en) 2018-05-31 2022-07-12 Tressbio Laboratory Co., Ltd. Heliostat apparatus
WO2019230150A1 (fr) * 2018-05-31 2019-12-05 株式会社ＳｏｌａｒＦｌａｍｅ Dispositif d'héliostat
JP7217567B1 (ja) * 2022-11-16 2023-02-03 株式会社Ｑｄジャパン 太陽追尾装置
WO2024105896A1 (fr) * 2022-11-16 2024-05-23 株式会社Ｑｄジャパン Suiveur solaire

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