WO2015095424A1 - Récepteur solaire - Google Patents

Récepteur solaire Download PDF

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Publication number
WO2015095424A1
WO2015095424A1 PCT/US2014/070999 US2014070999W WO2015095424A1 WO 2015095424 A1 WO2015095424 A1 WO 2015095424A1 US 2014070999 W US2014070999 W US 2014070999W WO 2015095424 A1 WO2015095424 A1 WO 2015095424A1
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WO
WIPO (PCT)
Prior art keywords
dish
hub
arm
reflector
ring
Prior art date
Application number
PCT/US2014/070999
Other languages
English (en)
Inventor
Ben Shelef
Shmuel Erez
Original Assignee
Ben Shelef
Shmuel Erez
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
Application filed by Ben Shelef, Shmuel Erez filed Critical Ben Shelef
Publication of WO2015095424A1 publication Critical patent/WO2015095424A1/fr

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Classifications

    • 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
    • F24S40/20—Cleaning; Removing snow
    • 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
    • F24S23/71—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with parabolic reflective surfaces
    • 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
    • F24S23/82—Arrangements for concentrating solar-rays for solar heat collectors with reflectors characterised by the material or the construction of the reflector
    • 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
    • F24S25/13—Profile arrangements, e.g. trusses
    • 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
    • F24S25/50—Arrangement of stationary mountings or supports for solar heat collector modules comprising elongate non-rigid elements, e.g. straps, wires or ropes
    • 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
    • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S2023/87—Reflectors layout
    • F24S2023/874—Reflectors formed by assemblies of adjacent similar reflective facets
    • 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
    • F24S2025/01—Special support components; Methods of use
    • F24S2025/012—Foldable support elements
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/20—Solar thermal
    • 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

  • Figure 1 shows a conventional solar thermal dish design (manufactured by
  • the truss is made from a very large number of members, which have to be bolted, riveted, or welded together, in the field.
  • the large part count introduces tolerance stack-up errors, and the large number of joints are all sources of stress concentration, fatigue, and structural creep.
  • Thermal The temperature of the PV cells has to be kept low - typically less than
  • Optical Any lit area covered with the wires or traces used to collect the electricity from the front surface of the cells plus any gaps between the cells, do not produce electricity and thus lead to a corresponding loss in efficiency. Since the cells are small and the current densities large, these effects are much more significant than in non-concentrating PV cells.
  • tracking errors move the sun away from the center of the image, so the point of peak illumination moves around and does not coincide with the center of the receiver, thus requiring the field of view of the receiver to extend around the nominal position of the sun and resulting in an image that is even darker in its periphery.
  • the invention described herein is a dish-based solar power generation system that has several novel features whose utility is to reduce or eliminate the problems outlined above. While each of these features provides independent benefits and can be utilized alone or in combination with other features to enhance prior art systems, they can be made to work in concert with each other to provide a complete system, and so they are described jointly in this specification.
  • the effect of a tracking error on the ringed receiver is always a predictable non- uniformity illumination pattern, with minimum and maximum illumination occurring on diametrically opposed points, along the direction of the tracking error (which is itself not known), and illumination varying smoothly between the minimum to maximum points.
  • the cells are divided into several interleaved groups referred to as circuits, with each circuit having cells distributed essentially uniformly around the ring.
  • Each circuit is wired internally in parallel so in and of itself can accommodate non-uniform illumination.
  • the circuits can then be wired in series and only incur minimal stringing losses.
  • the output from the individual cells of any of the circuits is also used as the sensor for providing feedback to the closed-loop tracking system.
  • the ACS in combination with the reflector tiles can create any optics of revolution, including a traditional parabolic dish, and thus can be used with other PCU technologies such as thermal PCUs.
  • the reflector tile technology by itself can create reflective optical bodies for other geometries such as for parabolic troughs or rigid heliostats.
  • the ACS can be used for any lightweight approximately round reflector such as a stretched membrane heliostat reflector, or even for non-reflective surface such as thin film solar panels.
  • the ACS is useful when constructing a non-optical receiver or transmitter such as a direction RF antenna, where the reflective surfaces reflect longer wavelength EM radiation, often not for the purpose of producing power but for signal communication.
  • Figure 8 System overview - Offset paraboloid with ring photovoltaic receiver according to an embodiment of the invention
  • Figure 21 Reflector tile - Sheet metal core according to an embodiment of the invention
  • Figure 33 Carrier - The ACS with vertical band spokes according to an embodiment of the invention
  • Figure 39 Carrier - ACS with conical hub according to an embodiment of the invention
  • Figure 43 Deployment mechanism, ACS with ribs according to an embodiment of the invention
  • Figure 48 Band spoke according to an embodiment of the invention
  • FIG. 6 shows an embodiment of this invention using a solar thermal PCU.
  • the system is comprised of a pedestal [60], pivot actuation machinery [66] at the top of the pedestal, a dish reflector [61], a hexapod mount [62], a thermal PCU [63] having a hot end [64], and a heat exchanger [65].
  • the hot end is shown surrounded by heat absorbing coils in which the thermodynamic fluid flows, but in other embodiments the heat can be transferred directly through the wall of the hot end.
  • the shape of the primary optical reflector [81] surface is not a regular paraboloid as is customarily used, but rather a revolved shape with a generatrix in the shape of a parabola whose optical axis is parallel but offset in the radial direction from the axis of revolution of the dish.
  • this shape is called an offset paraboloid and abbreviated as OP.
  • any plane that contains the axis of revolution is referred to as a "meridian plane", and the two principal directions of the plane are the axial and radial directions.
  • the local circumferential direction is perpendicular to a meridian plane.
  • the shape in a meridian plane that creates the geometry of revolution is called a generatrix.
  • a surface is considered to be a surface of revolution even if it is only partial to a complete surface or revolution spanning a complete revolution of the generatrix about the axis of revolution.
  • the angle of acceptance in solar systems is the angle by which light rays can deviate from the nominal direction (parallel to the optical axis of the dish) and still be directed into the aperture of the PCU.
  • the "full angle” is used, which is the angle between the two most extreme light rays that still get directed into the aperture, (as opposed to the "half angle", which is the angle between the nominal ray and an extreme ray.
  • the full angle value is typically twice that of the half angle value.
  • PCU power conversion unit
  • a PCU can be photovoltaic, thermal, or employ a yet- unclassified technology.
  • the alignable carrier structure replaces the carrier truss in conventional dishes. It differs from a conventional truss in several ways. First and foremost, unlike a conventional truss which is of a fixed shape, the ACS is an adjustable structure, designed to be assembled first, and then tweaked into shape. Second, rather than being built entirely from rigid members like a conventional truss, the ACS mimics the structure of a tensile spoked bicycle wheel, where the radial load carrying members (the spokes) are slender and flexible (bendable) and only loaded in tension. This is achieved by preloading them in tension to a sufficient degree - to a tension higher than the maximum compressive load they would have otherwise experienced. This way, when an external load is applied, the pretension decreases and compressive forces never occur.
  • the resultant structure is kinematic, highly rigid, and unlike a traditional dish truss does not have lattice arms that cantilever from the center outwards - the ACS is actually most stiff and precise right at the rim. Just like a bicycle wheel, all the spokes merely pull the rim inwards, and the rim is compressed in the circumferential direction. It is the imbalance in spoke tensions that results from the application of load that provides the rigidity of the rim in respect to the hub, both for in-plane and out-of-plane forces.
  • spokes [ 102, 116] are pre- tensioned so as to never go slack, and therefore the rim segments [112] are always loaded in compression.
  • the hub barrel [100] is compressed by the combined action of the spokes
  • the spokes create a very strong and rigid spatial relationship between the hub and the rim (both in and out-of-plane) but the spokes themselves can be bent by pushing on them sideways in their mid-spans. Since the load on the solar dish will be distributed, the ribs function to stiffen the spokes against such deflections. Additionally, the ribs mediate mechanically between the straight spokes and the curved guide rulers which establish the final optical shape of the dish. The guide rulers are attached to the ribs in-factory during fabrication, and so this process can be done to a very high degree of accuracy - much higher than the accuracy of field assembly.
  • the alignment of the dish is indifferent to which optical shape is being created by the guide rulers, and this is very important if the desired optical shape is not a simple paraboloid. Additionally, the alignment of the dish can take place before any reflector tiles are installed on the ACS. This is also important since reflector tiles can later be replaced without affecting alignment.
  • the ACS is assembled around its hub on its pedestal.
  • the hub is first oriented vertically so it can spin around the vertical axis without wobbling. At that point, the
  • the ACS is 8 m in diameter
  • the 36 spokes are 1/4" multi-stranded 7x19 steel cable, preloaded in tension at about 500 kgf of force.
  • a typical hub has a diameter of about 10% of the dish diameter, and a height of about 25% of the dish diameter.
  • Other embodiments can have different proportions, diameters, numbers of spokes, cable thicknesses, and material selections.
  • the number of rim segments can be reduced very significantly from the value of thirty-six. As this is done, the length of the rim segments increases, and they become more susceptible to buckling. However, even having as few as six segments is still an approximation to a round rim.
  • the hub of the ACS is its backbone and most rigid and dense component.
  • the tracking actuation mechanism attaches to the back-side crown of the hub, and the front-side crown attaches to the PCU mount.
  • the rest of the ACS structure is distributed and will not support a concentrated load at any single point. This is a positive trait that indicates that material is used efficiently.
  • the fiduciary is a kinematic coupling.
  • Kinematic couplings are used to connect two objects in a way that a) relieves any stresses due to thermal expansion or misalignments and b) allows them to be disassembled from each other and then reassembled in a highly repeatable way, so each reassembly results in the same spatial relationship between the objects.
  • the kinematic coupling is later used to attach the PCU and other optical elements to the fiduciary interface [141].
  • a rotary laser guide is fastened to the fiduciary interface.
  • the fiduciary interface for both the primary mirror (ACS) alignment guide and as the positioning mechanism for the PCU, there is no need to later align the position of the PCU to the focal point or axis of the ACS.
  • the fiduciary interface in the embodiment below contains two triplets of co-located conical depressions - an inner one [157] for the RLG, and an outer one for the PCU.
  • Figure 15 shows an embodiment of the RLG which uses two intersecting laser beams that rotate around the main dish axis. This rotation describes two coaxial cones of light that intersect at a circle, which becomes the reference for the rim.
  • a baseplate [150] is mounted to the inner fiduciary interface [157], leaving the outer one free for mounting the PCU.
  • An inner guide tube [151] is attached to the baseplate and is perpendicular to it.
  • a coaxial outer tube [152] encapsulates the inner tube [151] and rotates around it.
  • a suitable bearing (not shown) may be provided between the inner and outer tubes.
  • a rigid carrier plate [153] carried two lasers
  • the fiduciary has two kinematic couplings and thus two triplets of cones - an inner one and an outer one - with the alignment guide attached to the inner triplet, leaving the outer one for the PCU, so the alignment guide can be mounted even when the PCU (described later) is in place.
  • Figure 16 shows another embodiment, in which three tooling balls [160] are placed on a reference plate [161] that attaches to fiduciary interface [162].
  • the distance between the balls is pre-known and they define a reference axis in the same way that the fiduciary interface does.
  • the alignment of the dish relative to the balls is ascertained either using a laser radar (such as Nikon model MV224) or photo grammetry techniques, using the edges of the rim tubes [163] as the defining features of the inspected geometry.
  • the tooling balls can be made a permanent feature of the fiduciary plate itself, situated permanently in the inner set of conical depressions.
  • the ACS can additionally be used for any lightweight approximately round reflector such as a stretched membrane heliostat reflector, or even for non-reflective surface such as thin film solar panels or Fresnel-lens sheets.
  • any lightweight approximately round reflector such as a stretched membrane heliostat reflector, or even for non-reflective surface such as thin film solar panels or Fresnel-lens sheets.
  • the tiles held by the ACS are transparent, refracting the light to a focal point behind the plane of the ACS.
  • the spokes [330] are bands oriented roughly in parallel with the optical axis of the dish, to minimize shading.
  • the reflective surface [331] of the dish in this embodiment is a Fresnel paraboloid, comprised of two paraboloid rings with different focal lengths but sharing the same focal point. Openings [332] in the gap between the rings help reduce pressure differentials across the dish caused by
  • a Fresnel paraboloid can have two or more rings.
  • the used water flows [226] down the face of the dish and is collected using a gutter [225] located on its inner rim and so can be reclaimed, filtered, and reused, allowing for frequent daily cleaning cycles, and plentiful use of cleaning water. This results in a cleaner mirror and increased electricity production.
  • the cold end of the thermal engine is connected to the coolant duct that leads to the condenser [246], and to the pipe that bring coolant back from the pump [not shown].
  • the ring geometry becomes advantageous when its width is small enough so that the grid on the cells can conduct the electricity to bus bars that are outside the ring. This advantage starts to become significant when the ring is narrower than 2 cm, but this is highly dependent on the technology used to fabricate the front-surface collection layer of the PV cell.
  • the ring geometry becomes advantageous when the diameter of the ring is much wider than the spot size created by the natural divergence of the light coming from the sun, which allows the optics to remain principally 2-dimensional since the curvature of the ring is negligible. This advantage becomes significant when the diameter of the ring is at least 10 times its width, but this also depends on the optical design of the secondary optical element as described further below.
  • the term “narrow ring PV receiver” is used to designate a photovoltaic receiver whose active photovoltaic surface is shaped as a ring that is narrow enough for the receiver to benefit from the specific advantages discussed in the context where the term is used. It is useful to think of any receiver as having a "characteristic width” which is the dimension determining how difficult it is to perform a certain task such as cooling or wire routing. In a two dimensional receiver with a shape such as a square or a circle, this dimension is the square root of the area. Thus a 400 cm receiver is "20 cm across”. A one dimensional, or “narrow”, receiver is therefore one in which the characteristic width is much smaller than the square root of its area. A ring with a circumference of 200 cm and a width of 2 cm would qualify as such, since for the same area, its characteristic width is only 10% that of the characteristic width of a two dimensional receiver.
  • Section A— A shows a diagram of the cell mount in cross section.
  • the PV cells [251] are soldered to two layers of double-sided metalized Alumina ceramic [254], which are in turn soldered to each other and to a copper carrier ring [252].
  • the Alumina serves as structural support to the PV cell, since unlike copper, its coefficient of thermal expansion is close to that of the typically Germanium based cell.
  • the soldered metalized coatings of the Alumina serve as current paths from the cell to the foils or wires [253a-d] leading to the collection circuit board (not shown).
  • Another way to describe the wiring of cells into circuits is that the cells of each circuit are required to avoid clustering near any contiguous region of the ring, so as to prevent any localized optical effect from influencing only one of the circuits.
  • any quadrant of the ring will nominally have exactly 25% of the cells of each circuit, but since the number of cells is finite in reality it might have one cell more.
  • a sufficient condition is to require that each quadrant will not have more than one more than 25% of the cells, rounded upwards.
  • the ring receiver is two cells wide, then a similar scheme is employed, except a checkerboard-like pattern can be used. It is important in that case to ensure that each circuit has a similar number of cells in each of the two concentric cell rings.
  • Figure 27 shows the physical structure of the receiver, comprised of the conical copper ring and cells [271], collection circuit boards [279], a secondary optical element (SOE) [270], a cooling structure [272], and a positioning interface to the fiduciary [273].
  • the ring is shown with a slice cut-through for purposes of illustration. The wiring between the PV cells and the collection circuit boards is not shown.
  • the generatrix is a two-dimensional compound parabolic concentrator (CPC). Unlike a standard revolved CPC, which is revolved around its own axis, this secondary is revolved around the main dish axis, and so forms a ring shape.
  • the CPC is realized as a cast glass solid refractive body using total internal refraction, but in other embodiments can also be realized as two reflective surfaces faces (e.g. using coated
  • the accepting aperture face [274] can be further curved in an undulating manner in order to help homogenize the light, as shown by the dotted line [274a] depicting the cross section of the aperture face of the SOE.
  • the manner of undulation has to be determined empirically using a ray-tracing computer program by trying different undulation curves and observing the illumination homogeneity.
  • a compound parabolic concentrator [Figure 38a] is a well-known nonimaging concentrator comprised of two opposing parabolic arcs [380] each of whose respective focal points lie on its opposing arc or its continuation.
  • the optical axis of the CPC [381] is the line of symmetry between the arcs.
  • the shape just described is a two-dimensional shape, and in two-dimensional optics a CPC is an ideal concentrator, since it accepts all rays arriving at its large aperture [383] within a certain acceptance angle [384] of the optical axis and directs them into the small aperture [382].
  • the traditional three-dimensional embodiment of the a CPC is a well-known nonimaging concentrator comprised of two opposing parabolic arcs [380] each of whose respective focal points lie on its opposing arc or its continuation.
  • the optical axis of the CPC [381] is the line of symmetry between the arcs.
  • the shape just described is a two
  • Coolant fluid arrives by a distribution conduit [275] and is pushed out through distribution holes in its wall [276] located next to a wick [277] located on the copper ring carrier, on the opposite side of the PV cells.
  • the short distance between the distribution holes and the wick ensures that the wick is saturated with coolant irrespective of the orientation of the ring, guaranteeing uniform cooling all around the circumference of the ring.
  • the coolant is allowed to boil out of the wick, with the vapor flowing onto the larger evacuation conduit [278], which is connected to a condenser and a pump that leads back to the distribution conduit.
  • the condenser is located inside the hub, shown separately. The flow conduits between the distribution and evacuation conduits and the condenser and pump are not shown in this drawing.
  • the advantage of using a phase-change over simple convective cooling is that the evaporation temperature is constant around the ring, even if some of the cells receive more illumination due for example to a tracking error.
  • a localized increase in heat load results in a localized increase in temperature.
  • the same localized increase in heat load simply results in an increased rate of boiling over that region.
  • each of the three spheres that are part of the receiver slides along its shaft until it sits tangent in the corresponding conical depression in the fiduciary.
  • This mount is unique, stress-free, and can accommodate thermal expansion. Since the fiduciary has multiple sets of three cones, other devices such as the Laser Alignment Guide can be attached to it while the PV receiver is in place.
  • the SOE in this embodiment is reflective rather than refractive, and so the bulk glass is replaced by two reflective walls [304a-b], which are typically created by simple machining, turning, or electroforming.
  • each spoke's point of contact with the hub is at a tangent to the hub.
  • the spokes are in the radial position, and any further expansion of the CEM only induces tension in the spokes and compression in the CEM. That is, each spoke's point of contact with the hub is at a ninety degrees, i.e., perpendicular to the hub.
  • Figure 4 shows another embodiment of the invention, in which the ribs [430] are already pre-attached to their spokes.
  • the ribs can be made thin and able to flex and wrap around the hub since they only work in bending and cannot buckle sideways under load since the reflector tiles and the spoke prevent it.
  • the curved ruler guides (described in Figure 10, item 104) on the ribs are slotted in order to reduce resistance to the wrapping deformation.
  • Each hub-side tensioner consists of a flexible band [440] connecting the spoke
  • Figure 6 shows another embodiment of the hub-side tensioners, in which the axial adjustor carries the side-load imparted by the spoke without the benefit of the flexible band.
  • Figure 7 shows both crowns of the hub with axial tensioners.
  • the back-side tensioners [461] are made hollow, and torsion rods [462] extend through them to the front-side tensioners [460].
  • An input shaft [520] has an eccentric crank pin [521] that is engaged into an arm [522] (thus functioning as a cam mechanism).
  • the arm is further engaged into a slide bearing [523] that is attached to the frame [524] of the transmission.
  • a traction pad [525] that cyclically engages and disengages an inner traction surface of the output wheel [526].
  • a set of bearings [527] center the output wheel relative to the frame [524].
  • Figure 54 shows a third embodiment, in which a central hub [540] is mounted on the eccentric crank pin.
  • This hub mechanism is common in circular piston engines, such as have been built for piston-driven aviation engines.
  • Figure 60 shows the cross-section of one example of a pressure-unfurling arm [580], implemented as a hose.
  • the external sleeve is of a construction similar to a fireman's hose, e.g., a woven fabric sleeve [600] that can fold and assume a flat cross-section when unpressurized, and changes to a straight and round cross-section tube when pressurized.
  • a curved resilient spring member Inside of the sleeve is embedded a curved resilient spring member [601] that supports the arm when unpressurized, and gives it its curled shape for the stowed position.
  • the spring can be made of metal, or from a material such as fiberglass or carbon fiber.
  • Figure 62 depicts this embodiment from a different view point, showing the outside of the central collection gutter [620], connected to a drain pipe [621], connected to a water processing system [622] that includes a holding tank (or more than one, if multiple fluids are used), filtration system, and a replenishment port [623] for fluids lost through evaporation or leakage.
  • a fluid selection manifold [624] a pressure pump [625] and pressure pipe [626] to supply the fluid to the arms.
  • a wave front sensor measures the intensity across a light beam, as a function of the direction the light is traveling at any given point.
  • the measurement is taken by using three elements: an opaque surface with an array of transparent pinholes, a gap, and an imaging device.
  • Figure 64 shows a cross section of the device, showing the cooling channels [640], conical holes [641], frosted glass [642], and a front-side transparent glass sheet [643] for protection.
  • the plate is fabricated front two layers, and the seam-line [644] is shown throughout the cross section.
  • a second embodiment designed for smaller beams, is built around a thin sheet of glass with a front-side reflective coating.
  • the coating is etched (using chemical, plasma, or other standard technique) to create the array of pinholes.
  • On the back side of the glass is mounted a CCD camera, and so no frosted glass is necessary.
  • an Alignable Carrier Structure comprised of providing a hub and pre-attached spokes wrapped around said hub, and a circular expandable scissor mechanism configured to space the distal ends of the spokes in an equal manner around the hub, and further configured so that in its fully expanded state the mechanism is no shorter than the perimeter of the rim of the Alignable Carrier Structure.
  • Ribs may be attached to the back spokes and also wrapped around said hub.
  • aspects of the invention further modify the rim members to rigid tubes, and said tubes can include spherical protrusions or depressions at their ends.
  • aspects of the invention can further have the hub including two crowns, each connected to spokes on a different side of the plane defined by the rim, and further comprising a mechanism for moving said crowns away from each other in the axial direction, such that said motion increases the tension in the spokes.
  • aspects of the invention can further comprise at least one adjustment mechanism connecting a spoke to the hub, said adjustment mechanism capable of changing the distance between a fixed point on the spoke and a fixed point on the hub.
  • aspects of the invention can further comprise at least one adjustment mechanism connecting a spoke to the rim, said adjustment mechanism capable of changing the distance between a fixed point on the spoke and a fixed point on the rim, and can have said adjustment mechanism connect two spokes to a common point on the rim, said two spokes being coplanar, and can further have said point being between an adjacent pair of said rigid members of the rim.
  • aspects of the invention can further have at least one of said tiles comprise an optical surface partial to an optical shape having a focal region, and have said optical surface be reflective and of a shape of a portion of a paraboloid or functional approximation thereof, or approximate a Fresnel paraboloid or functional approximation thereof, or approximate a portion of a paraboloid whose focal distance is between 0.5 and 1.5 times the diameter of the rim or approximate a portion of a concave surface depressed near its center and whose deviation from a flat plane is smaller than 10% of the diameter of the rim, or approximate a portion of a flat reflector or functional approximation thereof, or approximate a portion of an offset revolved paraboloid comprising a generatrix in the shape of a parabola whose optical axis is parallel but radially offset from the axis of revolution, or approximate a portion of an offset revolved paraboloid whose focal distance is between 0.5 and 1.5 times the diameter of the rim.
  • aspects of the invention can further comprise a kinematic coupling having two mating components, one of said mating components being rigidly connected to said hub, and a power conversion unit (PCU) and a rigid structure connecting said PCU to said hub, said PCU encompassing said axis of revolution of the dish.
  • PCU power conversion unit
  • aspects of the invention can further comprise an actuation subsystem between said rigid structure and the hub, said actuation system configured to tilt said rigid structure thereby moving the PCU in relation to said axis of revolution of the dish.
  • aspects of the invention can further have the PCU be a thermal engine comprising a hot compartment and a cold compartment, and wherein said thermal engine is oriented such that the hot compartment encompasses said focal region, and the cold
  • compartment lies along the imaginary line connecting the hot compartment and the hub, and is closer to the hub.
  • aspects of the invention can further comprise a heat rejection device located inside said hub and connected to said cold compartment.
  • aspects of the invention comprise a solar receiver having a power conversion layer in the shape of a ring, said ring having a first axis of revolution, a photovoltaic active front surface, a back surface, a width and a diameter, said width being less than 10% of said diameter.
  • aspects of the invention can further have said power conversion layer be of a shape belonging to the group consisting of cylindrical ring, flat ring, conical ring.
  • aspects of the invention can further comprise an annular substrate in thermal contact with said back surface of said power conversion layer, said annular substrate having the same axis of revolution as said photovoltaic layer and a thermal conductivity better than 100 W/m-K, and can also be specifically made from Copper, Aluminum, alloys of Copper, alloys of Aluminum, or a combination thereof.
  • aspects of the invention can further comprise a ring shaped first conduit configured to deliver coolant fluid onto the annular substrate, and having an axis of revolution coincident with said first axis of revolution.
  • aspects of the invention can further have said power conversion layer be comprised of a plurality of PV cells, said photovoltaic cells are grouped into a first number of circuits, the cells within each circuit being electrically connected in parallel, and physically distributed around the ring so that any quadrant of the ring contains at most a third of the cells of any circuit, and can have the circuits be further connected to each other in series, and can further have at least six cells per circuit.
  • aspects of the invention can further comprise a reflector dish connected to it through a rigid structure, where said reflector dish can further be comprised of a hub, rim a plurality of spokes, and a plurality of tiles, said rim being a slender member lying principally in a plane and forming the approximate shape of a ring, said hub being a rigid member located inside said rim and extending out from said plane in both directions, said spokes being slender tensile members connecting the rim to the hub and preloaded in tension, and said tiles having reflective surfaces and collectively forming a reflective shape having a ring-shaped focal region, said focal region coinciding with said ring-shaped photovoltaic receiver.
  • aspects of the invention comprise an apparatus for converting light energy into electric energy, comprising a reflector having a reflective surface shaped as a surface of revolution having a first generatrix and a first axis of revolution, whereby the reflective surface is configured to focus reflected radiation arriving along a direction parallel said first axis of revolution onto a ringed-shaped focus area.
  • aspects of the invention can further comprise a ring-shaped photovoltaic receiver positioned at the ringed-shaped focus area.
  • aspects of the invention can further have the photovoltaic converter comprise a plurality of photovoltaic cells, and can further have the plurality of photovoltaic cells be divided into contiguous zones, each zone having several photovoltaic cells, wherein one cell from each zone is electrically connected in parallel to one cell from each of the other zones.
  • Optical - SOE optical - SOE
  • the ring-shaped receiver comprise an optical concentrator focusing light received at the ring-shaped area onto the photovoltaic converter, and further have said optical concentrator is shaped as a shape of revolution whose axis of revolution is coincident with said first axis of revolution.
  • aspects of the invention further have the steps of securing the core to the front membrane and securing the back membrane to the core comprise adhering the core to the front membrane and adhering the back membrane to the core while the front membrane is held over the bending mold.
  • aspects of the invention further have the step of fabricating a core comprise corrugating a sheet of metal, followed by slotting the surfaces of the sheet that do not belong to said front surface of the core, followed by bending said unslotted front surface to approximate said desired curved surface
  • aspects of the invention further have the hexapod comprise six rods defining a base and a top, and wherein at the base the six rods are connected to form three pairs, each of the three pairs being connected to an actuator.
  • aspects of the invention further have a rotary manifold configured to allow said rotary subsystem to rotate while providing a fluid path from said stationary member to said inlet.
  • aspects of the invention comprise a method for controlling the wall thickness of vacuum molded parts consisting of providing a vacuum mold, vacuum generator, a plastic sheet, and a radiative heater, and further pre-painting said plastic sheet in a pattern to thereby generate regions of varying heat absorbance, heating said plastic sheet with said radiative heater thus generating regions of different temperatures in said sheet according to the regions of varying heat absorbance, attaching said sheet to said vacuum mold, and applying said vacuum source to said vacuum mold so that said sheet is sucked to conform to the shape of the vacuum mold, whereby hotter regions deform and flow more readily as the sheet is stretches and so become thinner than colder regions.
  • aspects of the invention comprise an optical concentrator comprising two revolved surfaces having a common axis of revolution and whose generatrix is a compound parabolic concentrator whose axis is offset and tilted to the axis of revolution so that its small aperture is closer to the common axis of revolution than its large aperture.
  • aspects of the invention further comprise a solid ring of optically transparent material wherein the two said revolved surfaces are part of the surface of said solid of revolution and are configured for total internal refraction of propagating radiation.
  • aspects of the invention further have the ring further comprise a radiation accepting surface of revolution at a distal position from the axis of revolution and a radiation emitting surface of revolution proximal the axis of revolution, and wherein the generatrix of said radiation receiving surface is curved in an undulating manner configured to homogenize radiation emitted from said radiation emitting surface.
  • aspects of the invention further comprise a photovoltaic arrangement positioned to receive solar radiation from said emitting surface.
  • aspects of the invention further comprise a plurality of coupling nodes spread evenly about the rim, and wherein each of the upper spokes is paired with a corresponding one of the lower spokes, and wherein each pair of upper and lower spokes is coupled to one of the coupling nodes.
  • aspects of the invention further have the rim comprise a plurality of rim segments, and further comprise a plurality of central joints, wherein each central joint is coupled between two rim segments.
  • aspects of the invention further comprise a plurality of stiffeners, each attached to one of the lower spokes.
  • aspects of the invention further have each of the tiles coupled to two of the stiffeners.
  • each of the stiffeners comprise an elongated guide provided on each side thereof, and wherein each of the tiles is pressed against the guides along its reflective upper surface.
  • aspects of the invention further have the reflective upper surface of each tile shaped to approximate a portion of an offset revolved paraboloid comprising a generatrix in the shape of a parabola whose optical axis is parallel but radially offset from the axis of revolution.
  • aspects of the invention further have the reflective upper surface of each tile shaped so that the plurality of tiles reflect incident light onto a focal area in the shape of a ring.
  • each of the tiles comprise a front reflective membrane, a back membrane, and a core provided in between the front reflective membrane and the back membrane.
  • aspects of the invention further comprise actuators coupled to the back side of the hexapod to adjust the position of the solar converter.
  • aspects of the invention further have the solar converter further comprise a secondary optical element focusing the light reflected from the tiles onto the photovoltaic cells.
  • aspects of the invention further have the secondary optical element comprise a two-dimensional compound parabolic concentrator.
  • aspects of the invention further have the solar converter further comprise a cooling system for cooling the photovoltaic cells.
  • aspects of the invention further have the plurality of solar cells divided into contiguous zones, each zone having several photovoltaic cells, wherein one cell from each zone is electrically connected in parallel to one cell from each of the other zones.
  • aspects of the invention further have the hub further comprise a heat exchanger for cooling fluids received from the solar converter.
  • aspects of the invention further have the step of adjusting tension further comprise illuminating the rim with a laser to ensure all points on the rim lie in a single plane.
  • aspects of the invention further have the step of mounting a plurality of reflective tiles further comprise mounting a plurality of stiffeners onto the second plurality of spokes, and mounting the plurality of reflective tiles onto the stiffeners.
  • aspects of the invention further have the step of pressing each of the tiles against at least two of the elongated guides comprises fastening a plurality of resilient members between each tile and its respective stiffeners.
  • aspects of the invention further have the step of mounting a solar converter at a focal location of the plurality of reflective tiles.
  • aspects of the invention further have the step of fabricating a heat exchanger inside the hub, and providing fluid conduits between the heat exchanger and the solar converter.
  • aspects of the invention further have the step of mounting a solar converter comprising arranging a plurality of photovoltaic solar cells in a ring.
  • Aspects of the invention further comprise the step of dividing the ring into contiguous zones, each zone having several of the photovoltaic solar cells, and electrically connecting in parallel one cell from each zone to one cell from each of the other zones.
  • aspects of the invention further comprise the step of forming the reflective tile by shaping a front reflective membrane to a desired curvature, and sandwiching a flexible core in between the front reflective membrane and a back membrane.
  • aspects of the invention further having the step of shaping a front reflective membrane to a desired curvature comprising shaping the front reflective membrane to a curvature such that the plurality of tiles when mounted together reflect incident light onto a focal area in the shape of a ring.
  • aspects of the invention further have the step of shaping a front reflective membrane to a desired curvature comprising shaping the front reflective membrane to approximate a portion of an offset revolved paraboloid comprising a generatrix in the shape of a parabola whose optical axis is parallel but radially offset from the axis of revolution,
  • a self-cleaning solar reflector comprising: a reflector dish having a surface approximating a surface of revolution having an axis of revolution, a base located around said axis of revolution, a support frame coupled to the base; and, at least one fluid conduit attached to said support frame and configured to direct a cleaning agent onto said reflector dish.
  • the support frame or the arm are configured to rotate around the base.
  • a motor may be coupled to the support frame and provide rotational motive force to the support frame.
  • the motor may be energized using electrical power or flow of fluid, which may be the same fluid injected by the arm onto the dish surface.
  • the fluid conduit may be a flexible hose, and include a resilient member forcing the hose to curl inwards in the absence of fluid pressure, thus stowing itself near center of the reflector dish when not in use.
  • a reclamation system may be provided to collect liquid that was sprayed on the dish. This prevents harmful chemicals from reaching the ground. It also enables recycling of water and detergents.
  • the reclamation system may includes a gutter system, a reservoir, a conduit to deliver collected liquid from the gutter to the reservoir, a high pressure conduit coupled between the reservoir and the arm, and a pump to deliver liquid from the reservoir to the arm.
  • the injectors are provided on the arm are configured such that the collective injection front of all the injectors of the arm follows curvature of the dish surface.
  • the injectors are provided on the arm are configured such that distance between the surface of the dish to the outlet of the injector is the same for all of the injectors.
  • aspects of the invention include a method for cleaning a reflector dish, comprising: providing a foldable fluid conduit about center portion of the reflector dish, wherein the foldable fluid conduit comprises injection outlets; injecting fluid into the foldable conduit so as to unfold the foldable conduit and inject the fluid via the injection outlets; rotate the conduit around the axis of symmetry of the reflector dish.
  • the step of injecting fluid may comprises: a step of injecting air and a step of injecting at least one liquid.
  • the liquid may comprises water.
  • the step of injecting liquid comprises injecting detergent liquid followed by injecting rinsing liquid.
  • a rotary transmission comprising: a frame, an input shaft and an output wheel, the output wheel having a traction surface, said input shaft connected to an eccentric element which is in turn connected to the proximal end of at least one arm, said arm further connected to the frame through a linear bearing, and having a traction surface on it distal end, and configured to cyclically engage and disengage from the traction surface of the said outer wheel.

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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)
  • Photovoltaic Devices (AREA)

Abstract

La présente invention concerne un système et un procédé d'entretien d'un réflecteur. Le système peut être incorporé de façon à faire partie intégrante de l'ensemble parabole et il peut être activé de manière autonome ou à distance. Le système peut comporter un contrôleur programmé pour activer le système en fonction d'un programme établi ou en fonction d'une baisse de la réflectivité de la lumière provenant de la parabole. Le système comprend un bras pliable qui est plié lorsqu'il n'est pas utilisé de manière à ne pas gêner le fonctionnement de la parabole. Lorsqu'il est utilisé, le bras se déplie et il comporte des injecteurs permettant d'injecter des fluides, tels que de l'air et/ou des liquides permettant de nettoyer la surface de la parabole. Le bras peut comporter des injecteurs d'eau suivis d'injecteurs d'air de séchage, telle une lame d'air. Le système peut comporter un système de collecte de déchets liquides, tel qu'une gouttière et un réservoir.
PCT/US2014/070999 2013-12-17 2014-12-17 Récepteur solaire WO2015095424A1 (fr)

Applications Claiming Priority (2)

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US201361917252P 2013-12-17 2013-12-17
US61/917,252 2013-12-17

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Publication number Priority date Publication date Assignee Title
WO2020070527A1 (fr) 2018-10-04 2020-04-09 Gkamanis Achilleas Centrale solaire améliorée
CN112229264A (zh) * 2020-11-02 2021-01-15 黄家乐 一种家用太阳能真空管清洗设备
CN112303936A (zh) * 2020-10-30 2021-02-02 湖南哲能赫新能源有限责任公司 太阳能热水器支架折叠结构及太阳能热水器
CN112594946A (zh) * 2020-12-16 2021-04-02 浙江中控太阳能技术有限公司 一种吸热系统及减小吸热系统下降管振动的方法

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US20080163864A1 (en) * 2006-11-22 2008-07-10 Theodore Edward Larson Adjustable solar collector and method of use
EP2153914A1 (fr) * 2008-08-08 2010-02-17 Ingenieria y Marketing, S.A. Procédé pour le nettoyage de miroirs à section parabolique d'une centrale thermosolaire et appareil pour la réalisation dudit procédé
US20100058703A1 (en) * 2008-08-29 2010-03-11 Werner Extrusion Solutions LLC Solar trough mirror frame, rolling rib, roller, cleaning apparatus and method
US20110247679A1 (en) * 2010-04-13 2011-10-13 Ben Shelef Solar receiver
US20120132258A1 (en) * 2009-05-19 2012-05-31 Emanuele ALBANESE Solar collector
US20130055516A1 (en) * 2011-09-07 2013-03-07 Song-hao WANG Glass surface cleaning device

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US2814529A (en) * 1955-09-21 1957-11-26 Vernon R Arnt Water dispersing device
US3059889A (en) * 1960-06-24 1962-10-23 Blaw Knox Co Tracking mount
DE102004036094B4 (de) * 2004-07-24 2007-11-22 Deutsches Zentrum für Luft- und Raumfahrt e.V. Waschapparat für einen Parabolrinnenkollektor
US20080163864A1 (en) * 2006-11-22 2008-07-10 Theodore Edward Larson Adjustable solar collector and method of use
EP2153914A1 (fr) * 2008-08-08 2010-02-17 Ingenieria y Marketing, S.A. Procédé pour le nettoyage de miroirs à section parabolique d'une centrale thermosolaire et appareil pour la réalisation dudit procédé
US20100058703A1 (en) * 2008-08-29 2010-03-11 Werner Extrusion Solutions LLC Solar trough mirror frame, rolling rib, roller, cleaning apparatus and method
US20120132258A1 (en) * 2009-05-19 2012-05-31 Emanuele ALBANESE Solar collector
US20110247679A1 (en) * 2010-04-13 2011-10-13 Ben Shelef Solar receiver
US20130055516A1 (en) * 2011-09-07 2013-03-07 Song-hao WANG Glass surface cleaning device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020070527A1 (fr) 2018-10-04 2020-04-09 Gkamanis Achilleas Centrale solaire améliorée
CN112303936A (zh) * 2020-10-30 2021-02-02 湖南哲能赫新能源有限责任公司 太阳能热水器支架折叠结构及太阳能热水器
CN112229264A (zh) * 2020-11-02 2021-01-15 黄家乐 一种家用太阳能真空管清洗设备
CN112594946A (zh) * 2020-12-16 2021-04-02 浙江中控太阳能技术有限公司 一种吸热系统及减小吸热系统下降管振动的方法

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