WO1999020953A1 - Apparatus for the collection of solar radiation - Google Patents

Apparatus for the collection of solar radiation Download PDF

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Publication number
WO1999020953A1
WO1999020953A1 PCT/GR1998/000025 GR9800025W WO9920953A1 WO 1999020953 A1 WO1999020953 A1 WO 1999020953A1 GR 9800025 W GR9800025 W GR 9800025W WO 9920953 A1 WO9920953 A1 WO 9920953A1
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WO
WIPO (PCT)
Prior art keywords
reflectors
absorber
sun
exploitation
immovable
Prior art date
Application number
PCT/GR1998/000025
Other languages
French (fr)
Inventor
Manousos Pattakos
John Pattakos
Emmanouel Pattakos
Original Assignee
Manousos Pattakos
John Pattakos
Emmanouel Pattakos
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 Manousos Pattakos, John Pattakos, Emmanouel Pattakos filed Critical Manousos Pattakos
Priority to AU93619/98A priority Critical patent/AU9361998A/en
Publication of WO1999020953A1 publication Critical patent/WO1999020953A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/08—Mirrors
    • G02B5/09—Multifaceted or polygonal mirrors, e.g. polygonal scanning mirrors; Fresnel mirrors
    • 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
    • F24S23/77—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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0543—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the refractive type, e.g. lenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0547—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
    • 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
    • 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
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

Definitions

  • FIG 1 it is shown the vertical cut of a number of immovable reflectors properly oriented and having their centers on a circle C. There are also shown two sets of parallel beams, drawn the first with continuous and the second with dashed line, falling to the centers of the reflectors. After their reflection these two sets of beams focus the first on a point F and the second on a point F' of the circle C.
  • FIG 2 it is shown, from another perspective, the system of FIG 1.
  • FIG 3 it is shown in schematic view a reflector/concentrator made of fragments of plane mirror. These mirrors can have a variety of forms and are located and oriented on the surface of a cylinder according a specific array. There is also shown some of the falling and the reflected sun light beams, as well as a concentrator, the long cylindrical pipe, where fall all the reflected beams.
  • FIG 4 it is shown another embodiment.
  • the reflector/concentrator is made of fifteen oblong plane mirrors fixed, according a specific array, on the surface of a wide cylinder. They are shown four sets of falling beams, each consisting of five parallel beams, as well as their reflections which are neither parallel nor intersected light beams but fall, all of them, on the surface of the thin cylindrical absorber which is located on the surface of the wide cylinder. The extensions of the reflected beams out of the absorber are also shown.
  • Ri is a reflector having its reflecting surface normal to the plane P at their intersection point K] .
  • R 2 is another reflector having its reflecting surface normal to the plane P at their intersection point K 2 .
  • Ai and A are two parallel beams on the plane P, falling at the points Ki and K 2 of the reflectors Ri and R 2 .
  • Bi and B 2 shown also with continuous line, are their reflected beams, respectively.
  • X] and X are the normal lines, shown with dashed dot line, at the surfaces of the reflectors Ri and R 2 at the points Ki and K 2 , respectively.
  • the axes Xi and X 2 lie on the plane P because Ri and R 2 have their surfaces at their points Ki and K 2 normal to the plane P.
  • F is the intersection or focusing point of the reflected beams Bi and B 2 .
  • the reflected beams from Ki and K 2 focus at another point F'.
  • the line interval KjK is seen, or appears, from both F and F' points by the same angle of sight, and according plane geometry the point F' lies on a circle C defined by the points Ki, K 2 and F.
  • a reflector R n has its reflecting surface normal to the plane P at their intersection point K n .
  • the falling beam A n at the point K n of the reflector R n lies on the plane P and is parallel to Aj and A 2 .
  • the reflected beams from the points Ki, K 2 and K n focus, no matter what the direction of the falling light, on the plane P, is. If the focusing point is the F for some direction of the falling light, and F' for another direction of the falling light, then the Ki, K 2 and F define a circle C where the F' lies, since the K ⁇ K 2 is seen from both F and F' points by the same angle.
  • the points Ki, K n and F also define a circle where the F' lies, since the K]K n is seen from both F and F ' points by the same angle.
  • the reflecting point K n of the reflector R n has to be located on the circle C, otherwise it is impossible for the reflected beams to be always, for any direction of the falling light on the plane P, focused. So the first two reflectors Ri and R 2 define a unique circle C where must be located all the reflecting points Ki, K 2 , .. , K n in order to all the reflected beams Bj, B 2 , .. , B n are being focused, no matter what the direction of the falling light, on the plane P, is. If the orientation of the reflectors Ri, R 2 , .. , R n , having their reflecting points Ki, K 2 , ..
  • FIG 2 it is shown, drawn with continuous line, a first set of falling parallel beams lying out of the plane P and their reflections. It is also shown, drawn with dashed line, the projections on the plane P of these falling and reflected beams.
  • FIG 2 it is shown, drawn with continuous line, a second set of parallel falling beams on the plane P and their reflections also on the plane P.
  • the reflections of the first set of falling beams are neither focused lines, nor intersecting lines. According to the physical laws of optics, the falling beam A on the reflector R at its point K, and the reflected beam B from the point K of the reflector R need to be symmetrical about the normal line X to the surface of the reflector R, at its reflecting point K.
  • each reflector R Since the reflecting surface of each reflector R has been selected to be normal to the plane P at its reflecting point K which lies on the plane P, the X axis of the reflector lies on the plane P. This means that the projections, on the plane P, of the falling beam at point K and of the reflected beam from point K are also symmetrical lines about the X axis.
  • the first set of falling beams, at the reflecting points of all the reflectors, are parallel to each other, so their projections on the Plane P is a set of parallel lines, shown with dashed line.
  • the reflected beams would be both focused on a point of the circle C according the preceding theory, and they would be identical to the projections, on the plane P, of the reflections of the first set of falling beams. Consequently although the reflected beams are lines neither focused nor intersected with one another, they all intersect, viz. illuminate, the same line L which is normal to the plane P at the point F ' of the circle C, where the projections of the reflected beams are focused. As the direction of the falling parallel beams changes, the position of the illuminated line L changes too. This illuminated line moves along the circle C, remaining normal to the plane P, viz. describing a cylindrical surface.
  • a number of reflectors infinitesimal or not, are located on the surface of a cylinder, like a mosaic, having, each one, a point of its reflecting surface on the surface of the cylinder, each one being oriented to have its reflecting surface, at said point, parallel to the axis of said cylinder and being oriented to illuminate with the reflected light from all said points, for some direction of the falling light, the same generatrix line of the cylinder, then for any other direction of the falling light the reflected light from all said points will illuminate only some generatrix line of said cylinder.
  • This illuminated line is not immovable but moves on the surface of the cylinder, as the direction of the falling light changes.
  • the sun is a sphere being at a distance, from the earth, about one hundred times its diameter.
  • the falling light from the sun is not a set of parallel beams.
  • the reflected sun light from a plane reflector is a set of rather diverging beams as they recede from the reflector.
  • the surface of the absorber normal to the cylinder axis must be at least equal to the maximum width, normal to the axis of the cylinder, of the plane reflectors used, plus about one hundredth of the diameter of the cylinder.
  • Each slice of the reflector/concentrator rather scatters than focuses the falling sun light, depending on the position of the sun on the sky, but the scattering is along the same single line for all the slices, and that is the point. What is achieved is that all the reflected sun light will be concentrated into a restricted area.
  • FIG 4 it is shown how a thin slice, normal to the axis of the basic cylinder, of a reflector/concentrator made of plane mirrors, reflects and concentrates, on an absorber, the falling sun light beams.
  • the upper side of the intersecting plane they are shown four sets of falling beams, each consisting of five parallel beams and each corresponding to a position of the sun on the sky. They are also shown the corresponding sets of reflected beams. None of these sets of reflected beams is focused, not even converging, but on the other hand all the reflected beams fall on the surface of the thin cylindrical absorber.
  • the reflector/concentrator can be considered as made of a number of such slices and the reflected sun light from each one of these slices falls on the surface of the same thin cylindrical absorber, the result is that all the falling sun light, after its reflection, is concentrated on the surface of the absorber.
  • dashed dot line is shown the section of the cylinder of the reflectors by the intersecting plane.
  • the four directions of the falling sun light were selected for simpler figure, in an effort to make unnecessary the motion of the absorber. If these four directions were randomly selected, then for each of them the absorber had to shift to its correct position along the dashed dot circle.
  • a number of pieces of plane mirror are located to have each one its central point or its central line, in case of oblong piece, on the surface of a cylinder with a diameter of 10 m, each one is oriented to be parallel to the axis of the cylinder and all the mirrors are oriented to illuminate with the reflected sun light from their surfaces the same generatrix line of the cylinder.
  • the orientation of this, covered with mirrors, cylindrical section is neither too vertical nor too horizontal, depending on the latitude of the place, so that an optimum efficiency, all over the year, is achieved.
  • the concentration factor that is the ratio of the density of the falling radiation on the surface of the absorber to the density of the falling sun radiation on the surface of the reflectors, is, according to the preceding theory and the selected dimensions, more than 30.
  • the length of the covered with mirrors area is 200 m.
  • the absorber is supported by arms 5 m long. These arms are rotatably supported at the axis of the cylinder, so the absorber, as the arms rotate, moves on the surface of the cylinder, located at any moment to coincide with the illuminated, by the reflected and concentrated sun light, generatrix line.
  • the orientation of the axis of the cylinder can be anyone, yet the necessary movement of the absorber is minimized when this orientation becomes the East- West. If the orientation of the cylinder is at East- West, at the days around equinox the absorber remains immovable the whole day, and at the days around solstice the absorber must oscillate on the cylindrical surface for more than 2 m during the day, assuming 10 m diameter of cylinder. With 1 KW/m 2 density of falling sun light and assuming a total efficiency of 20%, this unit can produce about 200 KW of power output or about 1.5 MWh of energy per day, enough for a small village.
  • the absorber can be the steam generator of a steam turbine power unit or a support covered with photocells with proper cooling for immediate production of electric power, it can also be a combination of them, etc.
  • the absorber can also be a high temperature oven for e.g. the manufacturing of bricks etc.
  • the motion of the absorber may be mechanical or computerized.
  • the position of the sun on the sky, each moment of the year, is exactly known or calculated for every place of the earth, so the mechanism that controls the movement of the absorber can be simple: a computer or even a calculator defines the exact direction of the falling sun light each moment and, according the geometry of the construction, determines the position of the illuminated generatrix line on the cylinder so it drives the mechanism which moves the absorber along the surface of the cylinder.
  • Units made up of a steam turbine at the exit of the collector moving a pump for water supply, for irrigation purposes or heat supply to disallination units by means of steam generating into collector, and combinations of them may include no electrical components.
  • a feature of the cylindrical surface is that the length, covered with mirrors, can be limitless.
  • a substantially cylindrical surface may include a small taper.

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Abstract

As long as a number of immovable mirrors are arranged on a cylindrical surface and oriented such that for one incident sunlight direction the reflected light from all of them passes through the same point on the same cylindrical surface, then for any other incident direction the reflected sunlight will be concentrated at another point on the same cylinder. For the general case of non-normal incidence, the reflected light is spread out in a line along the cylinder in the long axis direction. The line stays on the cylinder as the sun moves through the sky, but moves around it. Plane or parabolic strip mirrors or a mirror array are used with an absorber that is rotated to coincide with the illuminated moving line to track and collect the sunlight.

Description

APPARATUS FOR THE COLLECTION OF SOLAR RADIATION
A number of documents, concerned with the concentration of the solar energy are already at hands, like the patents US5022064 A 19910604, US4525853 A 19850625, SU1560944 A 900430, JP3140754 - 910614, RU2024801 Cl 941215, SUl 163104 A 850623, RU2003005 Cl 931115 and USA Patent No 4,698,833 and applications like EPO 85103119.5 and PCT/AU93/00453. The common objective, of all of them, is to increase the density of the solar energy falling onto the absorber, for the solar density on the earth surface, being on the range of 1 KW/m2, is not sufficient for effective and economic abso tion/transformation.
Here, a sufficient and necessary geometrical condition is applied on the nature of the sun rays, and the result is the focusing of any ray, falling on a wide area, onto a restricted area constituting a line. In FIG 1 it is shown the vertical cut of a number of immovable reflectors properly oriented and having their centers on a circle C. There are also shown two sets of parallel beams, drawn the first with continuous and the second with dashed line, falling to the centers of the reflectors. After their reflection these two sets of beams focus the first on a point F and the second on a point F' of the circle C. In FIG 2 it is shown, from another perspective, the system of FIG 1. Here it is also drawn a third set of parallel beams, lying out of the plane of the circle, intersecting the reflectors at their centers and drawn with continuous line. Their reflections constitute another set of not parallel beams, out of the plane of the circle, not focused, however, on the other hand all intersecting a line L, drawn as dashed dot line, normal to the plane P at the point of the circle C where the projections of the reflected beams focus. In FIG 3 it is shown in schematic view a reflector/concentrator made of fragments of plane mirror. These mirrors can have a variety of forms and are located and oriented on the surface of a cylinder according a specific array. There is also shown some of the falling and the reflected sun light beams, as well as a concentrator, the long cylindrical pipe, where fall all the reflected beams.
In FIG 4 it is shown another embodiment. The reflector/concentrator is made of fifteen oblong plane mirrors fixed, according a specific array, on the surface of a wide cylinder. They are shown four sets of falling beams, each consisting of five parallel beams, as well as their reflections which are neither parallel nor intersected light beams but fall, all of them, on the surface of the thin cylindrical absorber which is located on the surface of the wide cylinder. The extensions of the reflected beams out of the absorber are also shown. According to FIG 1, Ri is a reflector having its reflecting surface normal to the plane P at their intersection point K] . R2 is another reflector having its reflecting surface normal to the plane P at their intersection point K2. Ai and A , shown with continuous line, are two parallel beams on the plane P, falling at the points Ki and K2 of the reflectors Ri and R2. Bi and B2, shown also with continuous line, are their reflected beams, respectively. X] and X are the normal lines, shown with dashed dot line, at the surfaces of the reflectors Ri and R2 at the points Ki and K2, respectively. The axes Xi and X2 lie on the plane P because Ri and R2 have their surfaces at their points Ki and K2 normal to the plane P. F is the intersection or focusing point of the reflected beams Bi and B2. If the parallel falling beams change direction but remain on the plane P, like the beams drawn with dashed line, then the reflected beams from Ki and K2 focus at another point F'. The line interval KjK is seen, or appears, from both F and F' points by the same angle of sight, and according plane geometry the point F' lies on a circle C defined by the points Ki, K2 and F. Suppose that a reflector Rn has its reflecting surface normal to the plane P at their intersection point Kn. The falling beam An at the point Kn of the reflector Rn lies on the plane P and is parallel to Aj and A2. Suppose also that the reflected beams from the points Ki, K2 and Kn focus, no matter what the direction of the falling light, on the plane P, is. If the focusing point is the F for some direction of the falling light, and F' for another direction of the falling light, then the Ki, K2 and F define a circle C where the F' lies, since the KιK2 is seen from both F and F' points by the same angle. The points Ki, Kn and F also define a circle where the F' lies, since the K]Kn is seen from both F and F' points by the same angle. These two circles are identical, namely are the same circle, since they have three common points: the F, the F' and the Ki. This means that the reflecting point Kn of the reflector Rn has to be located on the circle C, otherwise it is impossible for the reflected beams to be always, for any direction of the falling light on the plane P, focused. So the first two reflectors Ri and R2 define a unique circle C where must be located all the reflecting points Ki, K2, .. , Kn in order to all the reflected beams Bj, B2, .. , Bn are being focused, no matter what the direction of the falling light, on the plane P, is. If the orientation of the reflectors Ri, R2, .. , Rn, having their reflecting points Ki, K2, .. ,Kn on the circle C, is selected so that for a direction of the falling light on the plane P, the reflected beams from all the Ki, K2, .. , Kn points are focused on a point F of the circle C, then for any other direction of the falling light on the plane P, the reflected beams from the Ki, K2, .. ,Kn points will all focus on a point of the same circle C. This is a sufficient and necessary geometrical condition. It is assumed now that the direction of the parallel falling beams is not parallel to the plane P, as illustrated in FIG 2. In FIG 2 are shown, from another viewpoint, the reflectors of FIG 1. In FIG 2 it is shown, drawn with continuous line, a first set of falling parallel beams lying out of the plane P and their reflections. It is also shown, drawn with dashed line, the projections on the plane P of these falling and reflected beams. In FIG 2 it is shown, drawn with continuous line, a second set of parallel falling beams on the plane P and their reflections also on the plane P. The reflections of the first set of falling beams are neither focused lines, nor intersecting lines. According to the physical laws of optics, the falling beam A on the reflector R at its point K, and the reflected beam B from the point K of the reflector R need to be symmetrical about the normal line X to the surface of the reflector R, at its reflecting point K. Since the reflecting surface of each reflector R has been selected to be normal to the plane P at its reflecting point K which lies on the plane P, the X axis of the reflector lies on the plane P. This means that the projections, on the plane P, of the falling beam at point K and of the reflected beam from point K are also symmetrical lines about the X axis. The first set of falling beams, at the reflecting points of all the reflectors, are parallel to each other, so their projections on the Plane P is a set of parallel lines, shown with dashed line. If these parallel lines on the plane P were the actual falling beams then the reflected beams would be both focused on a point of the circle C according the preceding theory, and they would be identical to the projections, on the plane P, of the reflections of the first set of falling beams. Consequently although the reflected beams are lines neither focused nor intersected with one another, they all intersect, viz. illuminate, the same line L which is normal to the plane P at the point F' of the circle C, where the projections of the reflected beams are focused. As the direction of the falling parallel beams changes, the position of the illuminated line L changes too. This illuminated line moves along the circle C, remaining normal to the plane P, viz. describing a cylindrical surface. According to the preceding analysis, if a number of reflectors, infinitesimal or not, are located on the surface of a cylinder, like a mosaic, having, each one, a point of its reflecting surface on the surface of the cylinder, each one being oriented to have its reflecting surface, at said point, parallel to the axis of said cylinder and being oriented to illuminate with the reflected light from all said points, for some direction of the falling light, the same generatrix line of the cylinder, then for any other direction of the falling light the reflected light from all said points will illuminate only some generatrix line of said cylinder. This illuminated line is not immovable but moves on the surface of the cylinder, as the direction of the falling light changes. There is not similarity between a cylindrical reflector and the one described. Accordingly, if the mentioned reflectors on the surface of the cylinder are typical plane mirrors, then the reflected light from the entire surface of the reflectors illuminates a generatrix line of the cylinder but also it illuminates some space around this generatrix line. The illuminated space around said generatrix line has a minimum dimension greater or equal to the width of the plane reflectors. Consequently, in order to concentrate all the reflected beams on the absorber, the width of the absorber has to be at least equal to the width of the wider plane reflector.
The sun is a sphere being at a distance, from the earth, about one hundred times its diameter. The result is that the falling light from the sun is not a set of parallel beams. Due to this, the reflected sun light from a plane reflector is a set of rather diverging beams as they recede from the reflector. For each meter away from a plane reflector there is about one centimeter increase of the width of the set of the diverging reflected sun light beams. As a result, in order to fall all the reflected light on the absorber, the surface of the absorber normal to the cylinder axis must be at least equal to the maximum width, normal to the axis of the cylinder, of the plane reflectors used, plus about one hundredth of the diameter of the cylinder. It causes a limit for the possible concentration factor achievable with a reflector/concentrator like the one described, viz. made of plane reflectors. If the reflectors are, for example, of parabolic form then the concentration factor could be even higher, but in most cases the achievable concentration factor even with plane reflectors, is enough.
Each slice of the reflector/concentrator rather scatters than focuses the falling sun light, depending on the position of the sun on the sky, but the scattering is along the same single line for all the slices, and that is the point. What is achieved is that all the reflected sun light will be concentrated into a restricted area.
In FIG 4 it is shown how a thin slice, normal to the axis of the basic cylinder, of a reflector/concentrator made of plane mirrors, reflects and concentrates, on an absorber, the falling sun light beams. In the upper side of the intersecting plane they are shown four sets of falling beams, each consisting of five parallel beams and each corresponding to a position of the sun on the sky. They are also shown the corresponding sets of reflected beams. None of these sets of reflected beams is focused, not even converging, but on the other hand all the reflected beams fall on the surface of the thin cylindrical absorber. As the reflector/concentrator can be considered as made of a number of such slices and the reflected sun light from each one of these slices falls on the surface of the same thin cylindrical absorber, the result is that all the falling sun light, after its reflection, is concentrated on the surface of the absorber. With dashed dot line is shown the section of the cylinder of the reflectors by the intersecting plane. In FIG 4 the four directions of the falling sun light were selected for simpler figure, in an effort to make unnecessary the motion of the absorber. If these four directions were randomly selected, then for each of them the absorber had to shift to its correct position along the dashed dot circle.
An embodiment of the present invention is described below. A number of pieces of plane mirror, either of oblong form of width less than 15 cm or just small fragments with maximum dimension less than 15 cm, are located to have each one its central point or its central line, in case of oblong piece, on the surface of a cylinder with a diameter of 10 m, each one is oriented to be parallel to the axis of the cylinder and all the mirrors are oriented to illuminate with the reflected sun light from their surfaces the same generatrix line of the cylinder. An oblong absorber of a width 15 cm + ( 10 m / 100 ), or about 25 cm, is located to coincide with the illuminated generatrix line. Some 120° of the surface of the cylinder is covered with mirrors. The orientation of this, covered with mirrors, cylindrical section is neither too vertical nor too horizontal, depending on the latitude of the place, so that an optimum efficiency, all over the year, is achieved. The concentration factor, that is the ratio of the density of the falling radiation on the surface of the absorber to the density of the falling sun radiation on the surface of the reflectors, is, according to the preceding theory and the selected dimensions, more than 30. The length of the covered with mirrors area is 200 m. The absorber is supported by arms 5 m long. These arms are rotatably supported at the axis of the cylinder, so the absorber, as the arms rotate, moves on the surface of the cylinder, located at any moment to coincide with the illuminated, by the reflected and concentrated sun light, generatrix line. The orientation of the axis of the cylinder can be anyone, yet the necessary movement of the absorber is minimized when this orientation becomes the East- West. If the orientation of the cylinder is at East- West, at the days around equinox the absorber remains immovable the whole day, and at the days around solstice the absorber must oscillate on the cylindrical surface for more than 2 m during the day, assuming 10 m diameter of cylinder. With 1 KW/m2 density of falling sun light and assuming a total efficiency of 20%, this unit can produce about 200 KW of power output or about 1.5 MWh of energy per day, enough for a small village. The absorber can be the steam generator of a steam turbine power unit or a support covered with photocells with proper cooling for immediate production of electric power, it can also be a combination of them, etc. The absorber can also be a high temperature oven for e.g. the manufacturing of bricks etc. The motion of the absorber may be mechanical or computerized. The position of the sun on the sky, each moment of the year, is exactly known or calculated for every place of the earth, so the mechanism that controls the movement of the absorber can be simple: a computer or even a calculator defines the exact direction of the falling sun light each moment and, according the geometry of the construction, determines the position of the illuminated generatrix line on the cylinder so it drives the mechanism which moves the absorber along the surface of the cylinder. Mechanisms that define accurately the direction of the falling sun light exist already in the state of the art. A number of obvious modifications could be applied. For example a slightly conical instead of cylindrical surface could be used as the base surface for securing the immovable reflectors. In a case like this a compromise as regards the concentration factor, the scheme and the motion of the absorber has to be done, but the basic idea of the cooperation of neighboring slices remains.
Units made up of a steam turbine at the exit of the collector moving a pump for water supply, for irrigation purposes or heat supply to disallination units by means of steam generating into collector, and combinations of them may include no electrical components. A feature of the cylindrical surface is that the length, covered with mirrors, can be limitless. A substantially cylindrical surface may include a small taper.

Claims

1. Apparatus for the exploitation of sun radiation comprising: a number of substantially immovable reflectors and at least one moving absorber of sun radiation; characterized in that; said immovable reflectors are secured substantially on a cylindrical surface; said immovable reflectors are oriented substantially parallel to the axis of said cylindrical surface; said immovable reflectors are oriented to illuminate with the reflected sun light from their surfaces, for some direction of the falling sun light, the same generatrix line of said cylindrical surface; said moving absorber is moving substantially on said cylindrical surface, positioned to coincide with the illuminated, by the reflected sun light from said immovable reflectors, generatrix line; so that an economic and reliable construction is achieved for the focusing and exploitation of the sun radiation.
2. Apparatus for the exploitation of sun radiation according claim 1, characterized in that the diameter of said cylindrical surface is sufficiently smaller than the height of the covered with said immovable reflectors part of said cylindrical surface.
3. Apparatus for the exploitation of sun radiation according claim 1, characterized in that said immovable reflectors are plane mirrors.
4. Apparatus for the exploitation of sun radiation according claim 1, characterized in that the axis of said cylinder is oriented substantially East- West, so that the necessary movement of said absorber is minimized and said reflectors are used effectively.
5. Apparatus for the exploitation of sun radiation according claim 1, characterized in that said absorber comprises photo cells for immediate transformation of sun radiation into electricity.
6. Apparatus for the exploitation of sun radiation according claim 1 , characterized in that said absorber contains working means for the absorption and the transformation of the focused sun energy.
7. Apparatus for the exploitation of sun radiation according claim 1, characterized in that said absorber is a steam or vapor generator.
8. Apparatus for the exploitation of sun radiation according claim 1, characterized in that said immovable reflectors are of proper parabolic form so that the achieved concentration factor to be the desirable one.
PCT/GR1998/000025 1997-10-20 1998-10-15 Apparatus for the collection of solar radiation WO1999020953A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002012799A2 (en) * 2000-08-07 2002-02-14 Ven, Juha Device for utilizing concentrated solar energy
EP2233859A1 (en) * 2007-12-28 2010-09-29 Tecnologia Solar Concentradora, SL Solar energy concentrator/collector device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3868823A (en) * 1972-04-06 1975-03-04 Gulf Oil Corp Concentrator, method, and system for utilizing radiant energy
US4071017A (en) * 1976-07-01 1978-01-31 General Atomic Company Tensioned reflector support system
US4106480A (en) * 1975-12-15 1978-08-15 Halm Instrument Co., Inc. Reflective solar heat collector
FR2443693A1 (en) * 1978-12-07 1980-07-04 Gen Atomic Co Concentration of radiated solar energy - utilises mirror comprising series of flat strips reflecting energy onto focal area
US4520794A (en) * 1982-03-05 1985-06-04 North American Utility Construction Corporation Solar energy concentrating slat arrangement and collector

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3868823A (en) * 1972-04-06 1975-03-04 Gulf Oil Corp Concentrator, method, and system for utilizing radiant energy
US4106480A (en) * 1975-12-15 1978-08-15 Halm Instrument Co., Inc. Reflective solar heat collector
US4071017A (en) * 1976-07-01 1978-01-31 General Atomic Company Tensioned reflector support system
FR2443693A1 (en) * 1978-12-07 1980-07-04 Gen Atomic Co Concentration of radiated solar energy - utilises mirror comprising series of flat strips reflecting energy onto focal area
US4520794A (en) * 1982-03-05 1985-06-04 North American Utility Construction Corporation Solar energy concentrating slat arrangement and collector

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002012799A2 (en) * 2000-08-07 2002-02-14 Ven, Juha Device for utilizing concentrated solar energy
WO2002012799A3 (en) * 2000-08-07 2002-04-18 Ven Juha Device for utilizing concentrated solar energy
BE1013638A3 (en) * 2000-08-07 2002-05-07 Ven Juha Device for use of concentrated solar energy.
EP2233859A1 (en) * 2007-12-28 2010-09-29 Tecnologia Solar Concentradora, SL Solar energy concentrator/collector device
EP2233859A4 (en) * 2007-12-28 2013-05-01 Tecnologia Solar Concentradora Sl Solar energy concentrator/collector device

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