US20160040910A1 - Sunlight concentrating apparatus - Google Patents
Sunlight concentrating apparatus Download PDFInfo
- Publication number
- US20160040910A1 US20160040910A1 US14/780,229 US201414780229A US2016040910A1 US 20160040910 A1 US20160040910 A1 US 20160040910A1 US 201414780229 A US201414780229 A US 201414780229A US 2016040910 A1 US2016040910 A1 US 2016040910A1
- Authority
- US
- United States
- Prior art keywords
- width direction
- reflecting part
- support plate
- plate
- end portion
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
Images
Classifications
-
- F24J2/38—
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S50/00—Arrangements for controlling solar heat collectors
- F24S50/20—Arrangements for controlling solar heat collectors for tracking
-
- F24J2/1052—
-
- 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
- F24S23/74—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with trough-shaped or cylindro-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
- F24S23/74—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with trough-shaped or cylindro-parabolic reflective surfaces
- F24S23/745—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with trough-shaped or cylindro-parabolic reflective surfaces flexible
-
- 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
- F24S23/81—Arrangements for concentrating solar-rays for solar heat collectors with reflectors flexible
-
- 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
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
- F24S30/42—Arrangements for moving or orienting solar heat collector modules for rotary movement with only one rotation axis
- F24S30/425—Horizontal axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
- F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
- F24S2023/87—Reflectors layout
- F24S2023/872—Assemblies of spaced reflective elements on common support, e.g. Fresnel reflectors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/11—Driving means
- F24S2030/115—Linear actuators, e.g. pneumatic cylinders
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/15—Bearings
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/47—Mountings or tracking
Definitions
- FIG. 23 illustrates a relationship between the thickness of the support plate and the flexural rigidity of the reflecting part
- FIG. 26 is a perspective view of support beams and the rib members
- the sunlight concentrating apparatus 1 includes 23 units arrayed in the axial direction.
- the function of the rhombic support plates 32 laid on the mirror plates 31 will be described later.
- frames 91 forming a pair are provided on both sides of the reflecting part 3 in the X direction.
- a cam rail 722 is provided at a position that opposes each sliding rod 71 .
- the shape of the cam rail 722 as viewed in the axial direction (Y direction) is an arc shape centered on the rotation axis of the main shaft part 2 , i.e., the central axis J 1 (see FIG. 6 ).
- a pair of rollers 721 is further provided in the end portion of each sliding rod 71 that is close to the rotating mechanism 4 .
- the portions of the reflection surface 30 on the +X and ⁇ X sides of the central linear region 39 bend in the same manner.
- the reflecting part 3 that is tilted to one circumferential angular position about the central axis J 1 is indicated by dashed double-dotted lines.
- the target portion can be taken as a cantilever where the width direction corresponds to the lengthwise direction.
- the lengthwise direction of the above-described cantilever corresponds to the width direction of the reflection surface 30 of the sunlight concentrating apparatus 1 .
- the fixed end (end portion on the central linear region 39 side) of the target portion is fixed to the main shaft part 2 , and the amount of deflection of the free end (end portion of the support plate 32 in the width direction) is changed by the bending mechanism 7 in accordance with the rotation of the main shaft part 2 .
- a bending mechanism that uses power independent of that of the rotating mechanism 4 may be employed.
- a bending mechanism having a motor may be disposed below the end portions of the reflecting part 3 , and the end portions of the reflecting part 3 may be moved in the central normal direction by the power of the motor.
- the drive of the bending mechanism is controlled by the control part in accordance with the rotation of the main shaft part 2 by the rotating mechanism 4 .
Abstract
A sunlight concentrating apparatus includes a plate-like reflecting part, with an upper reflection surface extending in an axial and a width direction, and a lower surface having a central linear region fixed to a main shaft part. A pair of bending mechanisms bend the reflection surface by moving opposite end portions in a central normal direction in accordance with a rotation of the main shaft part. The reflecting part includes a mirror plate and a support plate thereon. In the support plate, the ratio between the distance in the width direction from each end portion in the width direction and the second moment of area at this distance is constant between the end portion and the central linear region, allowing the reflection surface to be bent in an are shape.
Description
- The present invention relates to a sunlight concentrating apparatus for concentrating sunlight onto a heat collecting part.
- In recent years, solar heat collecting systems that collect solar heat energy by concentrating sunlight and heating a heating medium have been put into practical use. It is important for solar heat collecting systems to efficiently collect the solar heat energy. For example, International Publication No. 2011/086825 (Document 1) discloses a technique for, in a sunlight concentrating apparatus that tilts a reflecting mirror in accordance with the movement of the sun, efficiently guiding (reflected light of) sunlight to a heat collecting means by changing the degree of curve of the reflection surface in accordance with the tilting position of the reflecting mirror. More specifically, in the sunlight concentrating apparatus of
Document 1, the reflecting mirror is supported at the center, and the degree of curve of the reflection surface is changed by raising and lowering both side edge portions of the reflecting mirror in accordance with the tilting position of the reflecting mirror. - Incidentally, in order to efficiently concentrate sunlight onto the heat collecting part, a sunlight concentrating apparatus that changes the deflection of the reflection surface while rotating (tilting) the reflection surface, as in
Document 1, sets the tilt angle and curvature of the reflection surface such that the reflection surface follows a parabola that is focusing on the position of the heat collecting part and whose axis of symmetry is a straight line parallel to sunlight in a plane perpendicular to the rotation axis and passing through the heat collecting part. However, keeping the curvature of the reflection surface substantially constant, i.e., bending the reflection surface in a generally arc shape is not easy, and efficiently guiding the sunlight emitted onto the entire reflection surface to the heat collecting part is difficult.Document 1 discloses a technique for providing the reflecting mirror with a concave portion to change the rigidity of the reflecting mirror in a transverse cross-sectional direction and thereby changing the degree of curve of the reflecting mirror, but even with this technique, it is not easy to bend the reflection surface in a generally arc shape. - The present invention is intended for a sunlight concentrating apparatus for concentrating sunlight onto a heat collecting part, and it is an object of the present invention to bend a reflection surface in a generally arc shape.
- The sunlight concentrating apparatus according to the present invention includes a main shaft part that is long in a predetermined axial direction, a plate-like reflecting part having an upper surface that is a reflection surface extending in the axial direction and a width direction perpendicular to the axial direction, and having a lower surface in which a central linear region that extends in the axial direction at approximately a center in the width direction is fixed to the main shaft part, a main shaft supporter for supporting the main shaft part rotatably about a central axis parallel to the axial direction, a rotating mechanism for rotating the main shaft part to tilt the reflection surface, and a pair of bending mechanisms for bending the reflection surface by moving opposite end portions in the width direction of the reflecting part in a similar manner in a central normal direction in accordance with rotation of the main shaft part, the central normal direction being a direction perpendicular to the axial direction and the width direction of the reflection surface. The reflecting part has a cross-sectional shape that is perpendicular to the width direction and that changes along the width direction to bend the reflection surface in a generally arc shape.
- According to the present invention, the reflection surface can easily bend in a generally arc shape. Consequently, sunlight can efficiently be concentrated onto the heat collecting part.
- In a preferred embodiment of the present invention, when a mirror plate of the reflecting part or a support plate laid on the mirror plate is taken as a target plate member, a ratio between a distance in the width direction from each end portion of the reflecting part in the width direction and a second moment of area of the target plate member at the distance is constant between the end portion and the central linear region, or a ratio between the distance and flexural rigidity of the reflecting part at the distance is constant between the end portion and the central linear region.
- In this case, in one aspect, the reflecting part includes the mirror plate and the support plate, the target plate member is the support plate, and the support plate has a triangular portion between the end portion and the central linear region, the triangular portion having a base located in the central linear region and a vertex opposing the base and located in the vicinity of the end portion. In another aspect, the reflecting part includes the mirror plate and the support plate, and the support plate has a portion whose thickness or width in the axial direction gradually increases from the end portion toward the central linear region to make the ratio between the distance and the flexural rigidity of the reflecting part at the distance constant between the end portion and the central linear region.
- In another preferred embodiment of the present invention, the reflecting part includes a mirror plate, and a support beam extending in the width direction and for supporting the mirror plate. The support beam has a cross-sectional shape that is perpendicular to the width direction and that changes along the width direction to make a ratio between a distance in the width direction from each end portion of the reflecting part in the width direction and flexural rigidity of the reflecting part at the distance constant between the end portion and the central linear region.
- In yet another preferred embodiment of the present invention, when a portion of the reflecting part between each end portion in the width direction and the central linear region is divided into a plurality of sections in the width direction, a ratio between a distance in the width direction from the end portion to each section and an average value of flexural rigidity of the reflecting part in the section is approximately constant in the plurality of sections.
- These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
-
FIG. 1 is a plan view of a solar heat collecting system; -
FIG. 2 is a plan view of part of a sunlight concentrating apparatus; -
FIG. 3 is a front view illustrating the vicinity of the center of the sunlight concentrating apparatus; -
FIG. 4 is a cross-sectional view of the sunlight concentrating apparatus; -
FIG. 5 illustrates a rotating mechanism; -
FIG. 6 is a cross-sectional view of the sunlight concentrating apparatus; -
FIG. 7 illustrates a rod supporter; -
FIG. 8 illustrates a change in the width of a plate member; -
FIG. 9 is a plan view of part of a reflecting part; -
FIG. 10 illustrates deflection curves of a reflection surface; -
FIG. 11 illustrates deflection curves of the reflection surface when rib members are omitted; -
FIG. 12 illustrates tangential angular differences; -
FIG. 13 illustrates tangential angular differences when the rib members are omitted; -
FIG. 14 illustrates another example of the reflecting part; -
FIG. 15 illustrates deflection curves of the reflection surface; -
FIG. 16 illustrates tangential angular differences; -
FIG. 17 illustrates a change in the thickness of a member; -
FIG. 18 is a cross-sectional view of another example of the reflecting part; -
FIG. 19 illustrates a relationship between the width of the support plate and the flexural rigidity of the reflecting part; -
FIG. 20 illustrates a change in the width of the support plate; -
FIG. 21 is a plan view of the reflecting part; -
FIG. 22 is a cross-sectional view of another example of the reflecting part; -
FIG. 23 illustrates a relationship between the thickness of the support plate and the flexural rigidity of the reflecting part; -
FIG. 24 illustrates a change in the thickness of the support plate; -
FIG. 25 is a perspective view of another example of the reflecting part; -
FIG. 26 is a perspective view of support beams and the rib members; -
FIG. 27 is a cross-sectional view of the reflecting part; -
FIG. 28 is a perspective view of a support beam; -
FIG. 29 illustrates a change in the height of the support beams; -
FIG. 30.A is a perspective view of another example of the support beams; -
FIG. 30.B is a perspective view of another example of the support beams; -
FIG. 31 illustrates a change in the height of another example of the support beams; -
FIG. 32 illustrates tangential angular differences; -
FIG. 33 is a perspective view of another example of the support beams; -
FIG. 34 is a perspective view of another example of the support beams; and -
FIG. 35 illustrates another example of the solar heat collecting system. -
FIG. 1 is a plan view of a Fresnel solar heat collectingsystem 10 according to an embodiment of the present invention. InFIG. 1 , X, Y, and Z directions that are orthogonal to one another are indicated by arrows (the same applies to drawings described later). The solarheat collecting system 10 includes aheat collecting part 11 in which a heating medium flows, and a plurality of (inFIG. 1 , six)sunlight concentrating apparatuses 1 for concentrating sunlight onto theheat collecting part 11 to heat the heating medium in theheat collecting part 11. Theheat collecting part 11 is a tubular member that is long in the Y direction. Both ends of theheat collecting part 11 are supported by a pair ofstrut parts 12, and theheat collecting part 11 is disposed on the +Z side of the plurality ofsunlight concentrating apparatuses 1. The heating medium in theheat collecting part 11 is, for example, circulated between theheat collecting part 11 and an external electric power generator and used for electric power generation by the electric power generator. In the following description, the +Z side is referred to as the “upper side,” and the −Z side is referred to as the “lower side.” - The plurality of
sunlight concentrating apparatuses 1 are arrayed in the X direction below theheat collecting part 11. Eachsunlight concentrating apparatus 1 includes a generally tubularmain shaft part 2 that is long in the Y direction, a reflectingpart 3 that is fixed to themain shaft part 2 and is long along the length of the main shaft part 2 (i.e., in the Y direction, which is hereinafter referred to as an “axial direction”), and arotating mechanism 4 that is disposed in the vicinity of the center of themain shaft part 2 in the axial direction. The reflectingpart 3 has a plate-like shape and has an upper surface serving as areflection surface 30. As will be described later, thereflection surface 30 is tilted by therotating mechanism 4 rotating themain shaft part 2. The following description focuses on one of thesunlight concentrating apparatuses 1, but the othersunlight concentrating apparatuses 1 have the same configuration. -
FIG. 2 is a plan view of part of thesunlight concentrating apparatus 1. The reflectingpart 3 includes a plurality of mirror plates 31 (indicated by solid lines inFIG. 2 ) that form thereflection surface 30, and a plurality of support plates 32 (indicated by bold broken lines inFIG. 2 ) that are in contact with the lower surfaces of the plurality ofmirror plates 3. Eachmirror plate 31 is a rectangular (e.g., a rectangle of 1 meter (m) by 1.2 m) flexible member, and the plurality ofmirror plates 31 are arrayed in the axial direction with a small space therebetween. Eachsupport plate 32 is a rhombic flexible member, and the plurality ofsupport plates 32 are arrayed in the axial direction with a space therebetween. In the present embodiment, fourmirror plates 31 arrayed in the axial direction are taken as a single unit, and thesunlight concentrating apparatus 1 includes 23 units arrayed in the axial direction. The function of therhombic support plates 32 laid on themirror plates 31 will be described later. -
FIG. 3 is a front view illustrating the vicinity of the center of thesunlight concentrating apparatus 1 in the axial direction, andFIG. 4 is a cross-sectional view of thesunlight concentrating apparatus 1 as viewed from the position indicated by arrows IV-IV inFIG. 3 . As illustrated inFIGS. 3 and 4 , themain shaft part 2 has amain shaft body 21 that is a tubular member, and themain shaft body 21 is fixed to the lower surface of the reflectingpart 3 via a fixingmember 23 that is long in the axial direction (Y direction). Themain shaft body 21 is supported by amain shaft supporter 5. To be more specific, themain shaft supporter 5 includes a plurality ofsupport bases 51 installed on the ground. Eachsupport base 51 has tworollers 52 that are in contact with the outer peripheral surface of themain shaft body 21, and tworoller supporters 53 that respectively rotatably support the tworollers 52 on thesupport base 51. While twosupport bases 51 are illustrated inFIG. 3 , in actuality three ormore support bases 51 are arranged in the axial direction with a space therebetween. In this way, themain shaft supporter 5 supports themain shaft part 2 rotatably about a central axis J1 parallel to the axial direction (in the present example, the central axis J1 of the main shaft body 21). -
FIG. 5 illustrates therotating mechanism 4 as viewed in the +Y direction from the −Y side. InFIG. 5 , part of themain shaft part 2 is illustrated in cross section. Therotating mechanism 4 includes acylinder part 41 that is, for example, an electric cylinder, a hydraulic cylinder, or a pneumatic cylinder, and thecylinder part 41 is fixed to the ground via acylinder supporter 42 and is rotatable about an axis parallel to the Y direction. Themain shaft body 21 is provided with aconnector plate 22 that protrudes from the outer peripheral surface, and the end of a piston of thecylinder part 41 is fixed with a pin to theconnector plate 22. As indicated by solid lines and dashed double-dotted lines inFIG. 5 , thecylinder part 41 advances and retracts the piston to rotate themain shaft part 2 about the central axis J1 and to thereby tilt thereflection surface 30 of the reflectingpart 3. In actuality, the deflection (deflection curve) of the reflectingpart 3 changes in accordance with the rotation angle of themain shaft part 2 as will be described later, butFIG. 5 illustrates the reflectingpart 3 that is assumed as not being bent. In the following description, when the reflectingpart 3 is not bent, a direction along thereflection surface 30 and perpendicular to the axial direction is referred to as a “width direction.” That is, when the reflectingpart 3 is not bent, thereflection surface 30 extends in the axial direction and in the width direction. -
FIG. 6 is a cross-sectional view of thesunlight concentrating apparatus 1 as viewed from the position indicated by arrows VI-VI inFIG. 2 . A linear region 39 (hereinafter, referred to as a “centrallinear region 39”) that extends in the axial direction at approximately the center of the width direction is set on the lower surface of the reflectingpart 3. The fixingmember 23 that is long in the axial direction is fixed to the centrallinear region 39, and the reflectingpart 3 is fixed to themain shaft part 2. Thus, the reflectingpart 3 extends on both sides in the width direction from the centrallinear region 39, which is fixed to themain shaft part 2. Focusing on a portion of the reflectingpart 3 on one side in the width direction inFIGS. 4 and 5 , the portion is supported by the fixingmember 23 in a cantilever state. In the following description, the direction of the normal to the centrallinear region 39 of the reflectingpart 3, i.e., the direction perpendicular to the axial direction and the width direction, is referred to as a “central normal direction.” Although the width direction and the central normal direction are respectively parallel to the X direction and the Z direction inFIG. 6 , the width direction and the central normal direction are fixed directions relative to the reflectingpart 3, and when the reflectingpart 3 tilts, the width direction and the central normal direction are also respectively inclined relative to the X direction and the Z direction. - As illustrated in
FIGS. 2 and 6 , a slidingrod 71 that extends in the axial direction is provided on the lower surface side (the side opposite the reflection surface 30) of each end portion of the reflectingpart 3 in the width direction. To be precise, slidingrods 71 forming a pair are disposed on both sides in the width direction of the portion of themain shaft part 2 on the +Y side of therotating mechanism 4, and slidingrods 71 forming another pair are disposed on both sides in the width direction of the portion of themain shaft part 2 on the −Y side of therotating mechanism 4, as illustrated inFIG. 1 . In other words, four slidingrods 71 are provided in thesunlight concentrating apparatus 1. As illustrated inFIG. 6 , each slidingrod 71 has a rectangular cross-sectional shape that is perpendicular to the axial direction. Themain shaft part 2 is provided with a plurality ofrod supporters 81 for supporting the slidingrods 71, and the plurality ofrod supporters 81 are arranged in the axial direction with a space therebetween (seeFIG. 2 ). -
FIG. 7 illustrates arod supporter 81 as viewed in the −X direction from the +X side. As illustrated inFIGS. 6 and 7 , eachrod supporter 81 includes a pair of fixedarms 811 that protrude on both sides in the width direction from the outer peripheral surface of themain shaft body 21, and a pair ofadapter plates 812 that are respectively provided at the ends of the pair of fixedarms 811. Asupport frame 813 that protrudes outward in the width direction is provided in the lower part of eachadapter plate 812, and aroller 814 that is in contact with the lower surface of the slidingrod 71 and aroller supporter 815 that rotatably supports theroller 814 on thesupport frame 813 are provided on thesupport frame 813. Each slidingrod 71 is supported movably in the axial direction by therollers 814 of the plurality ofrod supporters 81. Note that the position of each slidingrod 71 relative to themain shaft part 2 in the width direction and the central normal direction is constant, and when themain shaft part 2 rotates, each slidingrod 71 also rotates about the central axis J1 along with themain shaft part 2. - As illustrated in
FIGS. 1 and 3 , frames 91 forming a pair are provided on both sides of the reflectingpart 3 in the X direction. Referring to theframe 91 illustrated inFIG. 3 , acam rail 722 is provided at a position that opposes each slidingrod 71. The shape of thecam rail 722 as viewed in the axial direction (Y direction) is an arc shape centered on the rotation axis of themain shaft part 2, i.e., the central axis J1 (seeFIG. 6 ). A pair ofrollers 721 is further provided in the end portion of each slidingrod 71 that is close to therotating mechanism 4. Therollers 721 forming a pair are disposed on both sides of thecam rail 722 in the axial direction and are respectively in contact with two cam surfaces that are opposite end surfaces of thecam rail 722 in the axial direction. The distance between the opposite cam surfaces of thecam rail 722 is constant, but the position of thecam rail 722 in the axial direction varies depending on the circumferential angular position about the central axis J1. Thus, when the slidingrod 71 rotates about the central axis J1 along with themain shaft part 2, thecam rail 722 will change the axial positions of the pair ofrollers 721. In other words, therollers 721 and thecam rail 722 convert the rotation of themain shaft part 2 into axial movement of the slidingrod 71, and the slidingrod 71 moves (slides) in the axial direction. As described above, in thesunlight concentrating apparatus 1, therollers 721 and thecam rail 722 implement a slidingmechanism 72 for sliding the slidingrod 71 in the axial direction in accordance with the rotation of themain shaft part 2. - In actuality, the
cam rail 722 provided on the +Y side of therotating mechanism 4 and thecam rail 722 provided on the −Y side are symmetric with respect to a plane perpendicular to the axial direction at the center of themain shaft part 2 in the axial direction. Thus, the slidingrod 71 provided on the +Y side of therotating mechanism 4 and the slidingrod 71 provided on the −Y side slide in opposite axial directions to each other. In other words, reaction forces acting in opposite axial directions and having approximately the same magnitude act respectively on thecam rail 722 on the +Y side and thecam rail 722 on the −Y side from the slidingrod 71 on the +Y side and the slidingrod 71 on the −Y side. Thus, the reaction forces acting on theentire frame 91, which supports both of the cam rails 722, with the movement of both of the slidingrods 71 cancel out each other. This prevents theframe 91 from tilting or falling down due to the reaction forces acting with the movement of the slidingrods 71. - As illustrated in
FIGS. 6 and 7 , arib member 33 that extends in the axial direction is fixed to the lower surface of each end portion (hereinafter, simply referred to as an “end portion”) of thesupport plate 32 of the reflectingpart 3 in the width direction. In actuality, the end portions of the plurality ofsupport plates 32 arrayed in the axial direction are coupled to one another by therib member 33. Amotion transmission mechanism 73 is further provided between therib member 33 and the slidingrod 71. Themotion transmission mechanism 73 includes alift rod 74 that is fixed to therib member 33, and aguide part 75 that is fixed to the upper surface of the slidingrod 71. Thelift rod 74 is inserted in twoframe parts 743, which are provided on theadaptor plate 812 and arranged in the central normal direction, and is supported movably in the central normal direction. Thelift rod 74 has aslit 741 in the lower part, and apin member 742 that extends in the width direction is provided in theslit 741. Theguide part 75 has a plate-like shape extending in the axial direction and in the central normal direction and is disposed in theslit 741 of thelift rod 74. Theguide part 75 has aguide hole 751 that is long in a direction inclined relative to the axial direction, and thepin member 742 is inserted in theguide hole 751. In this way, the slidingrod 71 and the end portion of thesupport plate 32 of the reflectingpart 3 are mechanically coupled to each other, and when the slidingrod 71 slides and moves in the axial direction, thelift rod 74 moves in the central normal direction to change the amount of deflection of the end portion of the reflecting part 3 (the amount of displacement from the state where the reflectingpart 3 is not bent). - As described above, the sliding
rod 71, the sliding mechanism 72 (seeFIG. 3 ), and themotion transmission mechanism 73 implement abending mechanism 7 for changing the amount of deflection of the reflectingpart 3 in accordance with the rotation of themain shaft part 2. In actuality, thebending mechanism 7 disposed on the +X side of themain shaft part 2 and thebending mechanism 7 disposed on the −X side inFIG. 6 have the same configuration and move the opposite end portions of the reflectingpart 3 by the same distance in the same direction in accordance with the rotation of themain shaft part 2. That is, the bendingmechanisms 7 as a pair move both end portions of the reflectingpart 3 in a similar manner in the central normal direction in accordance with the rotation of themain shaft part 2. Accordingly, the portions of thereflection surface 30 on the +X and −X sides of the centrallinear region 39 bend in the same manner. InFIG. 6 , the reflectingpart 3 that is tilted to one circumferential angular position about the central axis J1 is indicated by dashed double-dotted lines. - As described previously, the
cam rail 722 on the +Y side of therotating mechanism 4 and thecam rail 722 on the −Y side inFIG. 3 are symmetric with respect to a plane perpendicular to the axial direction at the center of themain shaft part 2 in the axial direction, and the slidingrods 71 on the +Y side of therotating mechanism 4 and the slidingrods 71 on the −Y side slide by the same distance in opposite axial directions to each other in accordance with the rotation of themain shaft part 2. Moreover, the guide holes 751 in theguide parts 75 of the slidingrods 71 on the +Y side of therotating mechanism 4 and the guide holes 751 in theguide parts 75 of the slidingrods 71 on the −Y side have symmetrical shapes with respect to the above plane. Thus, the amount of deflection of the end portion in the width direction of the portion of the reflectingpart 3 on the +Y side of therotating mechanism 4 is the same as the amount of deflection of the end portion in the width direction of the portion of the reflectingpart 3 on the −Y side. Accordingly, deflection curves of the reflection surface 30 (curves indicating the amount of deflection at each position in the width direction) are appropriately the same over the axial direction. - In the solar
heat collecting system 10 inFIG. 1 , therotating mechanisms 4 of the plurality ofsunlight concentrating apparatuses 1 are controlled by a control part (not shown) in accordance with the movement of the sun. In other words, a parabola that is focusing on the position of theheat collecting part 11 and passes through the position (the center of the width direction) of thereflection surface 30 and whose symmetry axis is a straight line parallel to sunlight in a plane perpendicular to the axial direction and passing through theheat collecting part 11 is assumed for each possible altitude of the sun at the site where the solarheat collecting system 10 is installed, and the slope of the tangent to the parabola at the position of thereflection surface 30 and the curvature of the parabola at that position are acquired. Then, themain shaft part 2 is rotated so that the tilt angle at the center of thereflection surface 30 in the width direction (the position of the central linear region 39) matches the slope of the tangent to the parabola at the actual altitude of the sun. The shape of the cam rails 722 (the amount of travel of the sliding rods 71) and the shape of the guide holes 751 (the amount of travel of the lift rods 74) are further determined in accordance with the rotation angle of themain shaft part 2 so that the curvature of thereflection surface 30 is approximated to the curvature of the parabola at the actual altitude of the sun. This allows thereflection surface 30 to tilt in accordance with the movement of the sun and allows the deflection curve of thereflection surface 30 to change in accordance with the tilt of thereflection surface 30, thus enabling efficient guiding (concentrating) of (reflected light of) sunlight to theheat collecting part 11. - Here, the curvature of a typical cantilever will be described. For a cantilever with a free end to which a load W perpendicular to the lengthwise direction of the cantilever is applied,
Expression 1 is satisfied on the basis of the relationship between the bending moment and the bending stress, where x is the distance from the fixed end at an arbitrary position in the lengthwise direction of the cantilever, R is the radius of curvature at that position, I is the second moment of area (the second moment of area relative to the neutral axis) at that position, E is Young's modulus (modulus of longitudinal elasticity), and L is the entire length of the cantilever in the lengthwise direction. -
W·R=E·I/(L−x) (Expression 1) - When a ratio between the distance (L−x) from the free end in the lengthwise direction of the cantilever and the second moment I of area (or flexural rigidity E·I) at the position indicated by the distance in the lengthwise direction of the cantilever is made constant over the entire length of the cantilever, i.e., the second moment I of area is proportional to the distance (L−x), the radius of curvature R is constant over the entire length of the cantilever, irrespective of the magnitude of the load W (or the amount of deflection of the free end), and therefore the cantilever bends in an arc shape.
- More specifically, the second moment I of area is expressed as (b·h3/12), where a cross section of the cantilever perpendicular to the lengthwise direction has a rectangular shape, h is the width of the cross section in the direction of the load, and b is the width of the cross section in a direction perpendicular to the direction of the load. When the cantilever is a member having a constant width h in the direction of the load and a constant ratio between the distance (L−x) from the free end in the lengthwise direction of the cantilever and the width b in the direction perpendicular to the direction of the load at this distance, i.e., a plate member having a triangular shape as viewed in the direction of the load, the cantilever bends in an arc shape, irrespective of the magnitude of the load W (or the amount of deflection of the free end).
- For example, when the Young's modulus E of this plate member is 205800 megapascals (MPa), the entire length L of the cantilever in the lengthwise direction is 587 millimeters (mm), the width (thickness) of the cantilever in the direction of the load is 3 mm, the width b in the direction perpendicular to the direction of the load (see the longitudinal axis on the right side in
FIG. 8 ) linearly changes from 1000 mm at the fixed end to approximately 0 mm at the free end as indicated by a line A1 inFIG. 8 , and the load W applied to the free end is approximately 158 newtons (N), the amount of deflection at each position in the lengthwise direction of the cantilever (see the longitudinal axis on the left side inFIG. 8 ) will be values indicated by circles inFIG. 8 . The amount of deflection at each position in the lengthwise direction of the cantilever is on an arc A2 having a radius of curvature of 5000 mm, and the plate member bends in an arc shape over its entire length. - When a portion of each
support plate 32 of the reflectingpart 3 inFIG. 2 between each end portion in the width direction and the centrallinear region 39 is focused on as a target portion, the target portion can be taken as a cantilever where the width direction corresponds to the lengthwise direction. In this way, the lengthwise direction of the above-described cantilever corresponds to the width direction of thereflection surface 30 of thesunlight concentrating apparatus 1. The fixed end (end portion on the centrallinear region 39 side) of the target portion is fixed to themain shaft part 2, and the amount of deflection of the free end (end portion of thesupport plate 32 in the width direction) is changed by thebending mechanism 7 in accordance with the rotation of themain shaft part 2. Thesupport plate 32 has a constant thickness and has a generally triangular portion between each end portion in the width direction and the centrallinear region 39, the triangular portion having a base located in the centrallinear region 39 and a vertex opposing the base and located in the vicinity of the end portion. That is, the width h in the direction of the load (i.e., the central normal direction) is constant, and the ratio between the distance (L−x) from the free end in the lengthwise direction of the cantilever and the width b in the direction (i.e., axial direction) perpendicular to the direction of the load at this distance is constant. - In actuality, the
support plate 32, which is bonded to themirror plates 31, is not identical to the above-described cantilever, but the reflectingpart 3 includingsuch support plates 32 can approximate the cross-sectional shape of thereflection surface 30 perpendicular to the axial direction to an arc shape, i.e., can bend thereflection surface 30 in a generally arc shape, as compared to the case where the support plates have a rectangular shape as viewed in the central normal direction. This consequently allows not only the sunlight emitted to the vicinity of the center of thereflection surface 30 in the width direction but also the sunlight emitted to the vicinity of the end portions to be efficiently guided to theheat collecting part 11, thus further improving the performance of concentrating sunlight. - Here, the
rib members 33 provided at the end portions of the reflectingpart 3 will be described.FIG. 9 is a plan view of part of the reflectingpart 3 and illustrates the vicinity of asingle mirror plate 31. As described previously, therib members 33 are connected to the end portions of the plurality ofsupport plates 32 arrayed in the axial direction. Therib members 33 are also in contact with the lower surfaces of themirror plates 31, between twosupport plates 32 adjacent to each other in the axial direction. That is, at the end portions of the reflectingpart 3 in the width direction, themirror plates 31 are supported by therib members 33 in the region where thesupport plates 32 are not present. This suppresses deflection of themirror plates 31 under their own weight between the plurality ofsupport plates 32. -
FIG. 10 illustrates deflection curves of thereflection surface 30 obtained through finite-element analysis conducted on a diagonally hatched region B1 of the reflectingpart 3 inFIG. 9 , andFIG. 11 illustrates deflection curves of thereflection surface 30 obtained through finite-element analysis conducted on the region B1 of the reflectingpart 3 when therib members 33 are omitted. The vertical axes inFIGS. 10 and 11 indicate the amount of deflection of thereflection surface 30. The horizontal axes indicate the position in the width direction, with the vicinity of the 0-mm position corresponding to a portion in the vicinity of the centrallinear region 39, and the vicinity of the 600-mm position corresponding to the end portion of the reflectingpart 3. The length of the region B1 in the width direction is 600 mm, and the length thereof in the axial direction is 500 mm. Themirror plates 31, thesupport plates 32, and therib members 33 are respectively made of glass, aluminum, and carbon steel (SS400) and respectively have thicknesses of 0.95 mm, 0.6 mm, and 3.2 mm. The amount of deflection (the amount of lift by the bending mechanisms 7) of the end portions of eachsupport plate 32 is 25 mm. The deflection curves at axial positions indicated by arrows with reference signs T1, T2, and T3 inFIG. 9 are respectively given reference signs C11, C12, and C13 inFIG. 10 and are respectively given reference signs D11, D12, and D13 inFIG. 11 . InFIGS. 10 and 11 , an ideal arc is indicated by a reference sign C0 (the same applies toFIG. 15 described later). - As illustrated in
FIG. 11 , even when therib members 33 are omitted, the deflection curves D11 to D13 approximately coincide with the ideal arc C0 in the range from the 0-mm position to the 500-mm position in the axial direction. In the vicinity of the 600-mm position, however, the deflection curve D12 at the axial position T2 where themirror plate 31 is not in contact with thesupport plate 32 is approximately 1.4 mm away from the ideal arc C0. In contrast, in the case where therib members 33 are provided, the deflection curves C11 to C13 approximately coincide with the ideal arc C0 in the entire range in the width direction from the 0-mm position to the 600-mm position as illustrated inFIG. 10 . Note that a maximum distance between the deflection curves C11 to C13 and the ideal arc C0 is approximately 0.4 mm. -
FIG. 12 illustrates differences (hereinafter, referred to as “tangential angular differences”) between the angles of tangents to the deflection curves C11 to C13 and the angle of a tangent to the ideal arc C0 at each position in the width direction inFIG. 10 , andFIG. 13 illustrates differences (tangential angular differences) between the angles of tangents to the deflection curves D11 to D13 and the angle of a tangent to the ideal arc C0 at each position in the width direction inFIG. 11 . InFIGS. 12 and 13 , the vertical axes indicate the tangential angular difference, and the horizontal axes indicate the position in the width direction. InFIG. 12 , lines indicating tangential angular differences that correspond respectively to the deflection curves C11 to C13 are respectively given reference signs C21, C22, and C23, and inFIG. 13 , lines indicating tangential angular differences that correspond respectively to the deflection curves D11 to D13 are respectively given reference signs D21, D22, and D23 (the same applies toFIG. 16 described later). - In
FIGS. 12 and 13 , the magnitudes (absolute value) of the tangential angular differences become a maximum in the vicinity ofposition 600 mm in the width direction. More specifically, when therib members 33 are omitted, the magnitude of the tangential angular difference at the axial position T2 in the vicinity ofposition 600 mm is approximately one degree as illustrated inFIG. 13 (see the line D22). In contrast, when therib members 33 are provided, the magnitude of the tangential angular difference at either of the axial positions T1 to T3 in the vicinity ofposition 600 mm is less than 0.6 degrees as illustrated inFIG. 12 . The reflectingpart 3 including therib members 33 can thus more efficiently concentrate sunlight onto theheat collecting part 11. -
FIG. 14 illustrates another example of the reflectingpart 3. The reflectingpart 3 inFIG. 14 includes anotherrib member 33 a between therib member 33 provided at each end portion in the width direction and the centrallinear region 39. Like therib members 33, therib members 33 a are also connected to the generally triangular portions of the plurality ofsupport plates 32 arrayed in the axial direction. In the space between the generally triangular portions of twosupport plates 32 adjacent to each other in the axial direction, therib members 33 a are in contact with the lower surfaces of themirror plates 31. The reflectingpart 3 including therib members mirror plates 31. -
FIG. 15 illustrates deflection curves obtained through finite-element analysis conducted on a diagonally hatched region B1 of the reflectingpart 3 inFIG. 14 . InFIG. 15 , the deflection curves at axial positions indicated by arrows with reference signs T1, T2, and T3 inFIG. 14 are respectively given reference signs C31, C32, and C33.FIG. 16 illustrates differences (tangential angular differences) between the angles of tangents to the deflection curves C31 to C33 at each position in the width direction inFIG. 15 and the angle of a tangent to an ideal arc C0. InFIG. 16 , lines indicating the tangential angular differences that correspond respectively to the deflection curves C31 to C33 are respectively given reference signs C41, C42, and C43. - As illustrated in
FIG. 15 , the reflectingpart 3 including therib members FIG. 14 allows the deflection curves C31 to C33 to approximately coincide with the ideal arc C0 in the entire range from the 0-mm position to the 600-mm position mm in the axial direction, like the reflectingpart 3 inFIG. 9 . The magnitudes of the tangential angular differences even in the vicinity of the 600-mm position are less than 0.6 degrees as illustrated inFIG. 16 . To be specific, the reflectingpart 3 inFIG. 14 can suppress the magnitude of the tangential angular difference to a value less than or equal to 0.2 degrees in approximately a 90% range in the width direction from the 0-mm position to the 600-mm position. Thus, sunlight can more efficiently be concentrated onto theheat collecting part 11. - The reflecting
part 3 inFIG. 9 may include arib member 33 at only a position distanced from each end portion between the end portion and the centrallinear region 39. In thesunlight concentrating apparatus 1, when the plurality ofsupport plates 32 arranged in the axial direction with a space therebetween are laid on therectangular mirror plates 31 whose sides are parallel to the axial direction and the width direction, at least one rib member that is connected to the generally triangular portions of the plurality ofsupport plates 32 and in contact with themirror plates 31 is provided at a position distanced in the width direction from the centrallinear region 39. This suppresses deflection of themirror plates 31 under their own weight between the plurality ofsupport plates 32 and allows sunlight to be efficiently concentrated onto theheat collecting part 11. If a plurality of (three or more than three) rib members are provided, the deflection of themirror plates 31 under their own weight between the plurality ofsupport plates 32 can be further suppressed. - The technique for easily bending the
reflection surface 30 in a generally arc shape by making the ratio between the distance of each end portion of thesupport plates 32 in the width direction and the second moment of area at this distance constant between the end portion and the centrallinear region 39 may be implemented by changing the width h in the direction of the load (the thickness in the central normal direction). As described previously, the second moment I of area of a rectangular cross section is expressed as (b·h3/12). Thus, when a member that has a constant width b in the direction perpendicular to the direction of the load and that has a constant ratio between the distance (L−x) from the free end in the lengthwise direction of the cantilever and the cube of the width h in the direction of the load at this distance is used as a cantilever, this member can bend in an arc shape, irrespective of the magnitude of the load w (or the amount of deflection of the free end). - For example, when the Young's modulus E of this member is 205800 MPa, the entire length L of the cantilever in the lengthwise direction is 587 mm, the width b of the cantilever in the direction perpendicular to the direction of the load is 1000 mm, the width h in the direction of the load (the thickness of the member; see the longitudinal axis on the right side in
FIG. 17 ) changes from the fixed end to the free end as indicated by line A3 inFIG. 17 , and the load W applied to the free end is approximately 237 N, the amount of deflection at each position in the lengthwise direction of the cantilever (see the longitudinal axis on the left side inFIG. 17 ) will be values indicated by circles inFIG. 17 . The amount of deflection at each position in the lengthwise direction of the cantilever is on an arc A4 having a radius of curvature of 5000 mm, and the member bends in an arc shape over its entire length. - Thus, when the support plates having a rectangular shape as viewed in the central normal direction, like the
mirror plates 31, are employed and the thickness of the target portions of the support plates in the direction of the load (central normal direction) are changed as indicated by line A3 inFIG. 17 , the cross-sectional shape of thereflection surface 30 perpendicular to the axial direction can be approximated to an arc shape, i.e., thereflection surface 30 can be bent in a generally arc shape, as compared to the case of using rectangular support plates having a constant thickness. Consequently, sunlight can more efficiently be concentrated onto theheat collecting part 11. - As can be seen from
Expression 1, thesunlight concentrating apparatus 1 can approximate the cross-sectional shape of thereflection surface 30 more closely to an arc shape by making the ratio between the distance from each end portion in the width direction and the flexural rigidity (i.e., the product of the second moment I of area and the Young's modulus E) of the reflecting part as a whole at this distance constant between the end portion and the centrallinear region 39. The following is a description of such a reflecting part. -
FIG. 18 is a cross-sectional view of another example of the reflecting part and illustrates a cross section of a reflecting part 3 a taken perpendicular to the width direction. InFIG. 18 , the neutral axis in the cross section of the reflecting part 3 a is indicated by a dashed dotted line with a reference sign J2. The reflecting part 3 a has a three-layer structure of amirror plate 31, arear plate 35, and asupport plate 32 a, each member having a rectangular cross-sectional shape. For example, themirror plate 31 is made of glass, therear plate 35 is made of aluminum, and thesupport plate 32 a is made of carbon steel. The reflecting part 3 a differs only in that the width of thesupport plate 32 a in the axial direction (width in the lateral direction inFIG. 18 ) is changed in order to make the ratio between the distance in the width direction from each end portion in the width direction and the flexural rigidity of the reflecting part 3 a as a whole at this distance constant between the end portion and the centrallinear region 39. Note that themirror plate 31 and therear plate 35 have the same shape as viewed in the central normal direction. Themirror plate 31, therear plate 35, and thesupport plate 32 a each have a constant thickness over the width direction. - It is assumed here that when the portion of the reflecting part 3 a between the end portion in the width direction and the central
linear region 39 is taken as a single cantilever, a cross section of the cantilever taken perpendicular to the axis line (i.e., the axis line extending in the longitudinal direction of the cantilever) remains in a flat plane perpendicular to the axial line even after the reflecting part 3 a is bent and deformed by the bendingmechanisms 7. At this time, the bending strain c can be expressed as (ε=y/R) because it is proportional to a distance y from the neutral axis J2 (neutral plane) and inversely proportional to the radius of curvature (bend radius) R. The bending stress σg on themirror plate 31 is obtained as the product of the Young's modulus Eg of themirror plate 31 and the bending strain ε and thus can be expressed as (σg=Eg·y/R). Similarly, the bending stress σa on therear plate 35 can be expressed as (σm=Ea·y/R), and the bending stress σc on thesupport plate 32 a can be expressed as (σc=Ec·y/R), where Ea and Ec are respectively the Young's moduli of therear plate 35 and thesupport plate 32 a. - As described above, the bending stress linearly changes with respect to the distance y from the neutral axis J2. Thus, an integral value of stresses in the entire cross section of each member, including the
mirror plate 31, therear plate 35, and thesupport plate 32 a, can be obtained by multiplying the stress (i.e., average stress) at the center of the member in the thickness direction by the thickness and the axial width of the member. Thus, an integral value of stresses in the entire cross section of themirror plate 31 can be expressed as (tg·bg·Eg·((tg/2)+ta+tc−y0)/R), an integral value of stresses in the entire cross section of therear plate 35 can be expressed as (ta·ba·Ea·((ta/2)+tc−y0)/R), and an integral value of stresses in the entire cross section of thesupport plate 32 a can be expressed as (tc·bc·Ec·((tc/2)−y0)/R), by using the thickness tg and width bg of themirror plate 31, the thickness to and width ba of therear plate 35, the thickness tc and width be of thesupport plate 32 a, and the distance y0 from the lower end of thesupport plate 32 a to the neutral axis J2.Expression 2 is obtained by setting the sum of these integral values to zero and simplifying the sum with respect to y0. InExpression 2, Kg is (tg·bg·Eg), Ka is (ta·ba·Ea), and Kc is (tc·bc·Ec). -
y0={Kg((tg/2)+ta+tc)+Ka((ta/2)+tc)+Kc·tc/2}/(Kg+Ka+Kc) (Expression 2) - Thus,
Expression 2 yields the distance y0 from the lower end of thesupport plate 32 a to the neutral axis J2 when the thickness tg and width bg of themirror plate 31, the thickness ta and the width ba of therear plate 35, and the thickness tc of thesupport plate 32 a are made constant and the width be of thesupport plate 32 a is an arbitrary value. This distance y0 indicating the position of the neutral axis J2 is then used to obtain the flexural rigidity of themirror plate 31, the flexural rigidity of therear plate 35, and the flexural rigidity of thesupport plate 32 a, and the sum of the values of the flexural rigidity is obtained as the flexural rigidity of the reflecting part 3 a as a whole. The relationship between the width be of thesupport plate 32 a and the flexural rigidity of the reflecting part 3 a as a whole is as illustrated inFIG. 19 , where the Young's modulus Eg of themirror plate 31 is 80000 MPa, the thickness tg thereof is 0.93 mm, the width bg thereof is 333 mm, the Young's modulus Ea of therear plate 35 is 69000 MPa, the thickness ta thereof is 0.6 mm, the width ba thereof is 333 mm, the Young's modulus Ec of thesupport plate 32 a is 200000 MPa, and the thickness tc thereof is 3.2 mm. As the width of thesupport plate 32 a decreases, the position of the neutral axis J2 is closer to themirror plate 31, and the flexural rigidity of the reflecting part 3 a as a whole sharply decreases. - When the length of the portion of the reflecting part 3 a between the end portion in the width direction and the central
linear region 39 is 630 mm and the load W applied to the end portion is 99.9 N, the distribution of the width be of thesupport plate 32 a in order to fix the radius of curvature R of thereflection surface 30 to a constant value of 5400 mm can be obtained on the basis of the relationship expressed byExpression 1 and illustrated inFIG. 19 and will be as illustrated inFIG. 20 . In other words, when the width (axial width) of thesupport plate 32 a of the reflecting part 3 a at each position in the width direction (position from the central linear region 39) is set in accordance withFIG. 20 , the ratio between the distance from the end portion in the width direction and the flexural rigidity of the reflecting part 3 a as a whole at this distance is constant. In actuality, if the load w applied to the end portion is changed in accordance with a necessary curvature (reciprocal of the radius of curvature R) in order to make constant the product of the load w applied to the end portion and the radius of curvature R, approximately theentire reflection surface 30 can be bent with that curvature. -
FIG. 21 is a plane view of the reflecting part 3 a. The actual reflecting part 3 a is configured such that a plurality ofsupport plates 32 a densely arranged in the axial direction (lateral direction inFIG. 21 ) are fixed to asingle mirror plate 31 and a singlerear plate 35. The cross section of the reflecting part 3 a inFIG. 18 corresponds to a cross section of the reflecting part 3 a taken perpendicular to the width direction (longitudinal direction inFIG. 21 ) in an axial range indicated by arrow with a reference sign V1 inFIG. 21 , i.e., in a range where asingle support plate 32 a is present. - In the reflecting part 3 a illustrated in
FIG. 21 , the lengths of the portions of themirror plate 31 and therear plate 35 between each end portion in the width direction and the centrallinear region 39 are 600 mm. On the other hand, the length of the portion of thesupport plate 32 a between eachend portion 321 in the width direction and the centrallinear region 39 is 630 mm. In the case of thesupport plate 32 a, the axial width of the portion from the centrallinear region 39 to the 600-mm position in the width direction satisfies the relationship illustrated inFIG. 20 , whereas the axial width of theend portions 321 that protrude outward of the end portions of themirror plate 31 and therear plate 35 is constant, for example. Therib members 33 extending in the axial direction are fixed to theend portions 321 of thesupport plates 32 a. That is, theend portions 321 of thesupport plates 32 a are moved in the central normal direction by the bending mechanisms 7 (seeFIG. 7 ). The edges (right and left curved edges inFIG. 21 ) of eachsupport plate 32 a on opposite sides in the axial direction are symmetric. The plurality ofsupport plates 32 a arrayed in the axial direction are of the same shape. The plurality ofsupport plates 32 a may be formed as an integral plate member. - As described above, in the
sunlight concentrating apparatus 1, thesupport plates 32 a have a portion whose width in the axial direction gradually increases from each end portion of the reflecting part 3 a in the width direction toward the centrallinear region 39 in order to make the ratio between the distance in the width direction from the end portion and the flexural rigidity of the reflecting part 3 a at this distance approximately constant between the end portion and the centrallinear region 39. This allows thereflection surface 30 to be bent to more closely approximate an arc shape. Consequently, the performance of concentrating sunlight onto theheat collecting part 11 can be further improved. - Here, assume the case in which the
mirror plate 31 and therear plate 35 of the reflecting part 3 a inFIG. 21 have the same length in the width direction as thesupport plate 32 a (i.e., theend portions 321 of thesupport plates 32 a do not protrude outward of the end portions of the mirror plate 31). In this case, in order to bend thereflection surface 30 in an accurate arc shape even in the vicinity of the opposite edges of themirror plate 31 in the width direction, the axial width of the end portions of thesupport plates 32 a to which the load is applied needs to be zero, but it is not possible to apply a load to portions having a width of zero. Thus, for the above-assumed reflecting part, the vicinity of the opposite edges of themirror plate 31 in the width direction cannot be bent in an accurate arc shape. - In contrast, for the reflecting part 3 a illustrated in
FIG. 21 , theend portions 321 of thesupport plates 32 a in the width direction are located outward of the end portions of themirror plate 31, and the pair of bendingmechanisms 7 move theend portions 321 of thesupport plates 32 a in the central normal direction. Thus, thereflection surface 30 can be (ideally) bent in an accurate arc shape even in the vicinity of the opposite edges of themirror plate 31 in the width direction, i.e., thereflection surface 30 of themirror plate 31 as a whole can be bent in an accurate arch shape. This technique of using the support plates whose opposite end portions protrude outward of the opposite end portions of themirror plate 31 may be employed in the reflectingpart 3 that uses thetriangular support plates 32 or in reflecting parts that use support plates whose thicknesses change in the width direction (seeFIG. 17 andFIG. 24 described later). - Note that the
support plate 32 a may have edges on both sides in the axial direction that are asymmetric while having an axial width that satisfies the relationship illustrated inFIG. 20 . While the reflecting part 3 a can improve handling of themirror plate 31 and the efficiency of assembly of thesunlight concentrating apparatus 1 by providing therear plate 35 on the lower surface of themirror plate 31, therear plate 35 may be omitted depending on the design of thesunlight concentrating apparatus 1. -
FIG. 22 is a cross-sectional view of yet another example of the reflecting part. A reflecting part 3 a illustrated inFIG. 22 has a three-layer structure of amirror plate 31, asupport plate 32 a, and an auxiliary plate 34 (a structure for sandwiching thesupport plate 32 a). For example, themirror plate 31 is made of glass or the like, thesupport plate 32 a is a resin foam (here, polyurethane foam), and theauxiliary plate 34 is a resin plate. In the reflecting part 3 a, only the thickness of thesupport plate 32 a is changed in order to make the ratio between the distance in the width direction from each end portion in the width direction and the flexural rigidity of the reflecting part 3 a as a whole at this distance constant between the end portion and the centrallinear region 39. Note that themirror plate 31, thesupport plate 32 a, and theauxiliary plate 34 have the same shape (e.g., the same rectangular shape) as viewed in the central normal direction. - When, for example, the axial length of the reflecting part 3 a is 1 mm, the relationship between the thickness tp of the
support plate 32 a and the flexural rigidity of the reflecting part 3 a as a whole can be obtained in the same manner as inFIG. 19 and will be as illustrated inFIG. 23 , where the Young's modulus of themirror plate 31 is 80000 MPa, the Young's modulus of thesupport plate 32 a is 100 MPa, the Young's modulus of theauxiliary plate 34 is 5000 MPa, the thickness tg of themirror plate 31 is 0.93 mm, and the thickness is of theauxiliary plate 34 is 2 mm. - When, in the reflecting part 3 a, the axial length is 1 m, the length of the portion between each end portion in the width direction and the central
linear region 39 is 600 mm, and the load W applied to the end portion is approximately 300 N, the distribution of the thickness tp of thesupport plate 32 a in order to fix the radius R of curvature of thereflection surface 30 to a constant value of 6000 mm can be obtained in the same manner as inFIG. 20 and will be as illustrated inFIG. 24 . - Incidentally, in the distribution of thickness indicated by the line A3 in
FIG. 17 , the change in thickness is very small, and even a slight error in thickness affects the deflection of thereflection surface 30. In contrast, with thesupport plate 32 a having the distribution of thickness inFIG. 24 , the change in thickness tp can be increased by relatively lowering the Young's modulus, and the influence of an error in thickness on the deflection of thereflection surface 30 can thereby be reduced. In other words, the tolerance during manufacture of thesupport plate 32 a can be increased, and this facilitates the manufacture of thesupport plate 32 a. From this viewpoint, the Young's modulus of thesupport plate 32 a is preferably less than or equal to one tenth of the Young's modulus of themirror plate 31, and is more preferably less than or equal to one hundredth thereof (practically, greater than or equal to 1/10000). - In the manufacture of the reflecting part 3 a, for example, a lower mold having an inner shape that follows the distribution of thickness in
FIG. 24 and an upper mold having a flat inner shape are prepared. Next, themirror plate 31 is mounted on the inner surface of the upper mold, and theauxiliary plate 34 is mounted on the inner surface of the lower mold. Then, a liquid material for forming support plates is poured into the space between themirror plate 31 and theauxiliary plate 34 and hardened. This allows easy manufacture of the reflecting part 3 a. - As described above, in the
sunlight concentrating apparatus 1, thesupport plates 32 a have a portion whose thickness gradually increases from each end portion of the reflecting part 3 a in the width direction toward the centrallinear region 39 in order to make the ratio between the distance in the width direction from the end portion and the flexural rigidity of the reflecting part 3 a at this distance approximately constant between the end portion and the centrallinear region 39. This allows thereflection surface 30 to be easily bent in a generally arc shape. In addition, thesupport plates 32 a are made of a material having a lower Young's modulus than themirror plate 31. This increases a change in the thickness of thesupport plate 32 a, thus allowing easy manufacture of thesupport plate 32 a. - Note that, depending on the design of the reflecting part 3 a, the linear relationship between the distance in the width direction from each end portion and the flexural rigidity of the reflecting part at this distance may be satisfied by further changing the thicknesses of the
mirror plate 31 and the auxiliary plate 34 (i.e., changing the thicknesses of some or all of the plate members of the reflecting part 3 a). In addition to the above change in thickness, the axial width of thesupport plates 32 a or theauxiliary plate 34 may be changed. Moreover, theauxiliary plate 34 may be omitted from the reflecting part 3 a, and the reflecting part 3 a may be formed of four or more layers. - While the above-described
sunlight concentrating apparatus 1 uses thesupport plates support plates FIG. 25 is a perspective view of a reflectingpart 3 b including support beams 32 b, andFIG. 26 is a perspective view of the support beams 32 b andrib members 33 of thereflection part 3 b.FIGS. 25 and 26 illustrate a portion from the center (central linear region 39) to one end portion in the width direction (the same applies toFIGS. 28 , 30.A, 30.B, 33, and 34 described later).FIG. 27 is a cross-sectional view of the reflectingpart 3 b and illustrates a cross section of the reflectingpart 3 b taken perpendicular to the width direction. - The reflecting
part 3 b includes amirror plate 31, arear plate 35, the support beams 32 b, and therib members 33. Therear plate 35, the support beams 32 b, and therib members 33 are made of aluminum or steel, for example. The cross sections of themirror plate 31 and therear plate 35 perpendicular to the width direction have a rectangular shape. The cross section of the support beams 32 b perpendicular to the width direction has a C shape that opens downward, and the support beams 32 b are so-called C-shaped beams. In the reflectingpart 3 b, only the height of the support beams 32 b in the central normal direction (height in the direction indicated by an arrow V2 inFIG. 28 ) is changed, as illustrated inFIG. 28 , in order to make the ratio between the distance in the width direction from each end portion in the width direction and the flexural rigidity of the reflectingpart 3 b as a whole at this distance constant between the end portion and the centrallinear region 39. Note that the cross-sectional shapes of themirror plate 31 and therear plate 35 remain constant over the width direction. Therib members 33 extending in the axial direction have, for example, a “T-shaped” cross-section perpendicular to the axial direction, and this shape remains constant over the axial direction. - For convenience of description, it is assumed here that the axial length of the reflecting
part 3 b is 1 m and the reflectingpart 3 b is provided with twosupport beams 32 b arrayed in the axial direction. In this case, the relationship between the height h of the support beams 32 b (the height excluding the plate thickness is as illustrated inFIG. 27 ; the same applies below) and the flexural rigidity EI of the reflecting part 3 a as a whole can be obtained as (EI=1.03 h5−377.88 h4+145535.88 h3+1012938.62 h2+2320440.49 h+45148140.06) in the same manner as described above, where the Young's modulus of themirror plate 31 is 80000 MPa, the Young's modulus of the support beams 32 b is 69000 MPa, the Young's modulus of therear plate 35 is 69000 MPa, the thickness tg of themirror plate 31 is 0.93 mm, the thickness to of therear plate 35 is 0.6 mm, the plate thickness is of the support beams 32 b is 1.6 mm, and the axial width bs of the support beams 32 b is 45 mm. - Thus, when, in the reflecting
part 3 b, the length of the portion between each end portion in the width direction and the centrallinear region 39 is 600 mm and the load W applied to the end portion per one meter of the axial length is approximately 200 N (20.4 kgf), the distribution of the height h of the support beams 32 b in order to set the radius R of curvature of thereflection surface 30 to a constant value of 5400 mm is as illustrated inFIG. 29 . For the actual support beams 32 b, the height h in the vicinity of the end portions in the width direction (in the vicinity of 600-mm position in the width direction) remains constant at several millimeters. In this way, the support beams 32 b have a portion whose height in the central normal direction gradually increases from the end portions toward the centrallinear region 39. - As described above, the reflecting
part 3 b is provided with the support beams 32 b for supporting themirror plate 31 from the underside, and the support beams 32 b has a cross-sectional shape that is perpendicular to the width direction and that gradually changes along the width direction so that the ratio between the distance in the width direction from each end portion of the reflectingpart 3 b in the width direction and the flexural rigidity of the reflectingpart 3 b at this distance remains constant between the end portion and the centrallinear region 39. This allows thereflection surface 30 to be bent in a generally arc shape. By using the support beams 32 b having a C-shaped cross-section, it is possible to achieve high rigidity with a small cross-sectional area and to reduce the weight of the reflectingpart 3 b as compared to the case of using the support plates (e.g., the weight of the reflecting part is one- to three-tenths of the weight in the case of using the triangular support plates). In addition, C-shaped beams having a constant height are readily available in the market and are relatively low cost. The support beams 32 b can thus be manufactured easily at low cost by applying a simple process on such C-shaped beams (for example, the manufacturing cost can be reduced one-third in the case of manufacturing triangular support plates), and therefore, the manufacturing cost of thesunlight concentrating apparatus 1 can be reduced. In the region of the reflectingpart 3 b where the support beams 32 are not present, themirror plate 31 is supported by therib members 33. This suppresses deflection of themirror plate 31 under its own weight between the plurality of support beams 32 b. - The cross-sectional shape of the support beams 32 b is not limited to the shape illustrated in
FIG. 27 , and may be other shapes. For example, support beams 32 b having a T-shaped cross-sectional shape as illustrated inFIG. 30.A may be used. Thesupport beam 32 b inFIG. 30.A also has a portion whose height in the central normal direction gradually increases from the end portions in the width direction toward the centrallinear region 39. Depending on the cross-sectional shape, the support beams 32 b may have a portion whose axial width gradually increases from the end portions in the width direction toward the centrallinear region 39. Moreover, both the width and height of cross sections of the support beams 32 b may change along the lengthwise direction of the support beams 32 b (the width direction of the reflection surface in the sunlight concentrating apparatus 1). For example, asupport beam 32 b illustrated inFIG. 30.B has a C-shaped cross-section, and both of the height and width of the cross section gradually change along the lengthwise direction of thesupport beam 32 b. More specifically, the height of the cross section is high and the width is narrow in the vicinity of the centrallinear region 39 of the support beams 32 b. In the vicinity of the end portions, on the other hand, the height of the cross section is low and the width is wide. Thesupport beam 32 b inFIG. 30.B can easily be manufactured in, for example, a single process of press forming performed on a strip plate member having a constant width, and since no other processes such as cutting is necessary, the material can be used with no waste. For the reflectingpart 3 b using the support beams 32 b, the ratio between the distance in the width direction from each end portion of the reflectingpart 3 b in the width direction and the flexural rigidity of the reflectingpart 3 b at this distance also remains constant between the end portion and the centrallinear region 39. - While, in the case of the
support plates support plates FIG. 31 illustrates another example of the distribution of the height h of the support beams 32 b inFIG. 27 . For thesupport beam 32 b, the height h changes in a polyline form between each end portion of the reflectingpart 3 b in the width direction (position at which thebending mechanisms 7 lift up the reflectingpart 3 b; here, in the vicinity of the 600-mm position in the width direction inFIG. 31 ) and the central linear region 39 (in the vicinity of the 0-mm position in the width direction inFIG. 31 ). In the reflectingpart 3 b including such support beams 32 b, when the portion between the end portion and the centrallinear region 39 is divided into a plurality of sections U of a constant width in the width direction, the ratio between the distance in the width direction from the end portion to the center of each section U and an average value of the flexural rigidity of the reflectingpart 3 b in the section U is approximately constant in the plurality of sections U. In this case as well, thereflection surface 30 can be bent in a generally arc shape. -
FIG. 32 illustrates tangential angular differences between the angle of a tangent to the deflection curve at each position of the reflectingpart 3 b in the width direction and the angle of a tangent to an ideal arc.FIG. 32 corresponds toFIGS. 12 , 13 and 16, and the deflection curves are obtained through finite-element analysis. In the finite-element analysis, the axial width of the reflectingpart 3 b is assumed to be 1000 mm, and inFIG. 32 , lines indicating changes in tangential angular difference at positions that are respectively spaced by 0 mm, 250 mm, and 500 mm from one end in the axial direction are respectively given reference signs F1, F2, and F3. - The support beams 32 b in
FIG. 31 can suppress the magnitude of the tangential angular difference to less than or equal to 0.2 degrees at any axial position in the range from the 0-mm position to the 550-mm position in the width direction, i.e., in an approximately 92% range of the entire length of themirror plate 31 in the width direction. Thus, sunlight can efficiently be concentrated onto theheat collecting part 11. Note that the number of sections U between each end portion and the centrallinear region 39 in order to satisfy the condition that the ratio between the distance in the width direction from the end portion to each section U and the average value of the flexural rigidity of the reflectingpart 3 b in the section U is approximately constant in the plurality of sections U is, example, three or more, and preferably five or more (e.g., 20 or less). -
FIGS. 33 and 34 are perspective views of other examples of the support beams 32 b. Thesupport beam 32 b illustrated inFIG. 33 has a C-shaped cross-sectional shape and has a plurality of circular throughholes 322 in opposite side portions parallel to the central normal direction and the width direction (the longitudinal direction of thesupport beam 32 b). The plurality of throughholes 322 are arrayed at a fixed pitch in the width direction, and the diameters of the plurality of throughholes 322 gradually decrease from the vicinity of the end portions of thesupport beam 32 b in the width direction toward the centrallinear region 39, excluding the end portions. Thesupport beam 32 b illustrated inFIG. 34 has a T-shaped cross-sectional shape and has a plurality of circular throughholes 322 in a portion that is parallel to the central normal direction and the width direction. The plurality of throughholes 322 are arrayed at a fixed pitch in the width direction, and the diameters of the plurality of throughholes 322 gradually decrease from the vicinity of the end portions of thesupport beam 32 b in the width direction toward the centrallinear region 39, excluding the end portions. The support beams 32 b inFIGS. 33 and 34 have cross-sectional shapes that are perpendicular to the width direction and that change intermittently along the width direction. - For the reflecting
parts 3 b including the support beams 32 b inFIGS. 33 and 34 , when the portion between each end portion and the centrallinear region 39 is divided into a plurality of sections U in the width direction, the ratio between the distance in the width direction from the end portion to the center of each section U and an average value of the flexural rigidity of the reflectingpart 3 b in the section U is approximately constant in the plurality of sections U. This allows thereflection surface 30 to be bent in a generally arc shape. In addition, the weight of the support beams 32 b can be reduced by forming the plurality of throughholes 322 in the support beams 32 b. Note that the support beams 32 b in FIGS. 28 and 30.A may also have a plurality of throughholes 322 to adjust the flexural rigidity in each section. - As described above, in the
sunlight concentrating apparatus 1, the reflecting part having a cross-sectional shape that is perpendicular to the width direction and that changes along the width direction (preferably, approximately over the width direction) so that thereflection surface 30 can be bent in a generally arc shape can be achieved in various forms. - The above-described
sunlight concentrating apparatus 1 can be modified in various ways. For example, the ratio between the distance from each end portion in the width direction and the second moment of area at this distance may be made constant between the end portion and the centrallinear region 39, by changing the thickness in the central normal direction in one range of a target portion of the support plate in the width direction (e.g., an approximately 80% range of the entire length from the fixed end) and changing the axial width in the other range. Alternatively, both of the thickness in the central normal direction and the width of the axial direction may be changed as necessary. For example, it is possible to employ a support plate whose target portion as viewed in the central normal direction has a generally triangular shape having a blunt vertex in the end portions and whose thickness in the central normal direction changes only in the vicinity of the end portions. As described above, the support plates in which the ratio between the distance in the width direction from each end portion in the width direction and the second moment of area at this distance is constant between the end portion and the centrallinear region 39 can be implemented in various forms (the same applies to the case where the ratio between the distance in the width direction from each end portion of the reflecting part in the width direction and the flexural rigidity of the reflection part at this distance is constant). - The
support plates 32 of the reflectingpart 3 may be omitted. In this case, themirror plate 31 is configured such that the ratio between the distance in the width direction from each end portion in the width direction and the second moment of area at this distance is constant between the end portion and the centrallinear region 39.FIG. 35 illustrates an example of such amirror plate 31 in which a plurality ofrhombic mirror plates 31 are densely arrayed. As described above, in thesunlight concentrating apparatus 1, thereflection surface 30 can be bent in a generally arc shape on condition that, when themirror plates 31 of the reflectingpart 3 or thesupport plates 32 laid on themirror plates 31 are taken as a target plate member, the ratio between the distance in the width direction from each end portion of the reflectingpart 3 and the second moment of area of the target plate member at this distance is constant between the end portion and the centrallinear region 39. Note that the axial widths and the thicknesses of the above-describedsupport plates mirror plates 31 inFIG. 35 may be changed in stages along the width direction. - The
sunlight concentrating apparatus 1 may include therotating mechanism 4 having a motor and rotate themain shaft part 2 via a speed-reduction mechanism. Alternatively, the slidingmechanism 72 may use mechanical elements (e.g., gears) other than cams to slide the slidingrods 71 in the axial direction in accordance with the rotation of themain shaft part 2. Moreover, in themotion transmission mechanism 73, the slidingrods 71 and the end portions of the reflectingpart 3 may be mechanically coupled to each other by a link mechanism, for example, so that the end portions of the reflectingpart 3 are moved in the central normal direction along with the sliding of the slidingrods 71. - Depending on the design of the
sunlight concentrating apparatus 1, a bending mechanism that uses power independent of that of therotating mechanism 4 may be employed. For example, a bending mechanism having a motor may be disposed below the end portions of the reflectingpart 3, and the end portions of the reflectingpart 3 may be moved in the central normal direction by the power of the motor. In this case, the drive of the bending mechanism is controlled by the control part in accordance with the rotation of themain shaft part 2 by therotating mechanism 4. - The heating medium in the
heat collecting part 11 of the solarheat collecting system 10 may be used in applications other than electric power generation. Thesunlight concentrating apparatus 1 having thereflection surface 30 that is a variable curved surface may be installed in facilities other than the solarheat collecting system 10. - The configurations of the above-described preferred embodiments and variations may be appropriately combined as long as there are no mutual inconsistencies.
- While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore to be understood that numerous modifications and variations can be devised without departing from the scope of the invention.
-
-
- 1 Sunlight concentrating apparatus
- 2 Main shaft part
- 3, 3 a, 3 b Reflecting part
- 4 Rotating mechanism
- 5 Main shaft supporter
- 7 Bending mechanism
- 11 Heat collecting part
- 30 Reflection surface
- 31 Mirror plate
- 32, 32 a Support plate
- 32 b Support beam
- 33, 33 a Rib member
- 39 Central linear region
- 321 End portion (of support plate)
- J1 Central axis
Claims (17)
1. A sunlight concentrating apparatus for concentrating sunlight onto a heat collecting part, comprising;
a main shaft part that is long in a predetermined axial direction;
a plate-like reflecting part having an upper surface that is a reflection surface extending in said axial direction and a width direction perpendicular to said axial direction, and having a lower surface in which a central linear region that extends in said axial direction at approximately a center in said width direction is fixed to said main shaft part;
a main shaft supporter for supporting said main shaft part rotatably about a central axis parallel to said axial direction;
a rotating mechanism for rotating said main shaft part to tilt said reflection surface; and
a pair of bending mechanisms for bending said reflection surface by moving opposite end portions in said width direction of said reflecting part in a similar manner in a central normal direction in accordance with rotation of said main shaft part, said central normal direction being a direction perpendicular to said axial direction and said width direction of said reflection surface,
wherein said reflecting part has a cross-sectional shape that is perpendicular to said width direction and that changes along said width direction to bend said reflection surface in a generally arc shape.
2. The sunlight concentrating apparatus according to claim 1 , wherein
when a mirror plate of said reflecting part or a support plate laid on said mirror plate is taken as a target plate member, a ratio between a distance in said width direction from each end portion of said reflecting part in said width direction and a second moment of area of said target plate member at said distance is constant between said each end portion and said central linear region, or a ratio between said distance and flexural rigidity of said reflecting part at said distance is constant between said each end portion and said central linear region.
3. The sunlight concentrating apparatus according to claim 2 , wherein
said reflecting part includes said mirror plate and said support plate,
said target plate member is said support plate, and
said support plate has a triangular portion between said each end portion and said central linear region, said triangular portion having a base located in said central linear region and a vertex opposing said base and located in the vicinity of said each end portion.
4. The sunlight concentrating apparatus according to claim 3 , wherein
said mirror plate is a rectangular plate having sides parallel to said axial direction and said width direction,
said reflecting part further includes another support plate that is disposed apart in said axial direction from said support plate and that is laid on said mirror plate, and
said another support plate has a triangular portion between said each end portion and said central linear region, said triangular portion having a base located in said central linear region and a vertex opposing said base and located in the vicinity of said each end portion.
5. The sunlight concentrating apparatus according to claim 4 , wherein
said reflecting part further includes a rib member that is connected to said triangular portion of said support plate and said triangular portion of said another support plate and in contact with said mirror plate at a position distanced in said width direction from said central linear region.
6. The sunlight concentrating apparatus according to claim 2 , wherein
said reflecting part includes said mirror plate and said support plate, and
said support plate has a portion whose thickness gradually increases from said each end portion toward said central linear region to make the ratio between said distance and the flexural rigidity of said reflecting part at said distance constant between said each end portion and said central linear region.
7. The sunlight concentrating apparatus according to claim 6 , wherein
said support plate is formed of a material having a lower Young's modulus than said mirror plate.
8. The sunlight concentrating apparatus according to claim 2 , wherein
said reflecting part includes said mirror plate and said support plate, and
said support plate has a portion whose width in said axial direction gradually increases from said each end portion toward said central linear region to make the ratio between said distance and the flexural rigidity of said reflecting part at said distance constant between said each end portion and said central linear region.
9. The sunlight concentrating apparatus according to claim 3 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
10. The sunlight concentrating apparatus according to claim 1 , wherein
said reflecting part includes:
a mirror plate; and
a support beam extending in said width direction and for supporting said mirror plate, and
said support beam has a cross-sectional shape that is perpendicular to said width direction and that changes along said width direction to make a ratio between a distance in said width direction from each end portion of said reflecting part in said width direction and flexural rigidity of said reflecting part at said distance constant between said each end portion and said central linear region.
11. The sunlight concentrating apparatus according to claim 10 , wherein
said support beam has a portion whose height in said central normal direction or whose width in said axial direction gradually increases from said each end portion toward said central linear region.
12. The sunlight concentrating apparatus according to claim 1 , wherein
when a portion of said reflecting part between each end portion in said width direction and said central linear region is divided into a plurality of sections in said width direction, a ratio between a distance in said width direction from said each end portion to each section and an average value of flexural rigidity of said reflecting part in said each section is approximately constant in said plurality of sections.
13. The sunlight concentrating apparatus according to claim 4 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
14. The sunlight concentrating apparatus according to claim 5 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
15. The sunlight concentrating apparatus according to claim 6 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
16. The sunlight concentrating apparatus according to claim 7 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
17. The sunlight concentrating apparatus according to claim 8 , wherein
with respect to said width direction, opposite end portions of said support plate are located outward of opposite end portions of said mirror plate, and
said pair of bending mechanisms moves said opposite end portions of said support plate in said central normal direction.
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013071174 | 2013-03-29 | ||
JP2013-071174 | 2013-03-29 | ||
JP2013172890 | 2013-08-23 | ||
JP2013-172890 | 2013-08-23 | ||
PCT/JP2014/056904 WO2014156725A1 (en) | 2013-03-29 | 2014-03-14 | Sunlight collection device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160040910A1 true US20160040910A1 (en) | 2016-02-11 |
Family
ID=51623706
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/780,229 Abandoned US20160040910A1 (en) | 2013-03-29 | 2014-03-14 | Sunlight concentrating apparatus |
Country Status (6)
Country | Link |
---|---|
US (1) | US20160040910A1 (en) |
EP (1) | EP2980507A4 (en) |
JP (1) | JP6018700B2 (en) |
CN (1) | CN105308398A (en) |
AU (1) | AU2014246335B2 (en) |
WO (1) | WO2014156725A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10859291B2 (en) * | 2015-01-23 | 2020-12-08 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Parabolic trough collector module, parabolic trough collector module unit and solar thermal power station |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10001297B1 (en) * | 2017-02-20 | 2018-06-19 | James T Ganley | Free-hanging parabolic trough reflectors for solar energy conversion systems |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2825326A (en) * | 1954-04-23 | 1958-03-04 | Jr William D Flynn | Reflector panel |
US4138994A (en) * | 1977-07-14 | 1979-02-13 | Shipley Jr Robert M | Solar heating unit |
US4166446A (en) * | 1976-12-03 | 1979-09-04 | Bbc Brown Boveri & Company Limited | Solar collector |
US5191876A (en) * | 1992-03-04 | 1993-03-09 | Atchley Curtis L | Rotatable solar collection system |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4106484A (en) * | 1977-03-31 | 1978-08-15 | Mega Analytical Research Services, Inc. | Adjustable solar concentrator |
US4141626A (en) * | 1977-05-31 | 1979-02-27 | Fmc Corporation | Method of and apparatus for collecting solar radiation utilizing variable curvature cylindrical reflectors |
US4719903A (en) * | 1985-11-21 | 1988-01-19 | Powell Roger A | Variable aperture, variable flux density, aerospace solar collector |
HU51370A (en) * | 1988-01-22 | 1990-04-30 | ||
JP2891074B2 (en) * | 1993-12-10 | 1999-05-17 | 三菱電機株式会社 | Reflector fixing device |
CN100545543C (en) * | 2007-08-28 | 2009-09-30 | 东北电力大学 | Utilize CD to gather solar energy and be converted into the method and the device of electric energy |
WO2010083292A1 (en) * | 2009-01-14 | 2010-07-22 | Skyfuel, Inc. | Apparatus and method for building linear solar collectors directly from rolls of reflective laminate material |
AU2010342008B2 (en) * | 2010-01-18 | 2014-09-25 | Hitachi Zosen Corporation | Solar light collecting device and solar heat collecting facility |
US20120275040A1 (en) * | 2011-04-27 | 2012-11-01 | Massachusetts Institute Of Technology | Precision parabolic mirror structures |
-
2014
- 2014-03-14 EP EP14775805.6A patent/EP2980507A4/en not_active Withdrawn
- 2014-03-14 AU AU2014246335A patent/AU2014246335B2/en not_active Ceased
- 2014-03-14 WO PCT/JP2014/056904 patent/WO2014156725A1/en active Application Filing
- 2014-03-14 CN CN201480018318.0A patent/CN105308398A/en active Pending
- 2014-03-14 US US14/780,229 patent/US20160040910A1/en not_active Abandoned
- 2014-03-14 JP JP2015508303A patent/JP6018700B2/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2825326A (en) * | 1954-04-23 | 1958-03-04 | Jr William D Flynn | Reflector panel |
US4166446A (en) * | 1976-12-03 | 1979-09-04 | Bbc Brown Boveri & Company Limited | Solar collector |
US4138994A (en) * | 1977-07-14 | 1979-02-13 | Shipley Jr Robert M | Solar heating unit |
US5191876A (en) * | 1992-03-04 | 1993-03-09 | Atchley Curtis L | Rotatable solar collection system |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10859291B2 (en) * | 2015-01-23 | 2020-12-08 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Parabolic trough collector module, parabolic trough collector module unit and solar thermal power station |
Also Published As
Publication number | Publication date |
---|---|
CN105308398A (en) | 2016-02-03 |
EP2980507A1 (en) | 2016-02-03 |
AU2014246335A1 (en) | 2015-10-29 |
JPWO2014156725A1 (en) | 2017-02-16 |
AU2014246335B2 (en) | 2016-10-20 |
WO2014156725A1 (en) | 2014-10-02 |
EP2980507A4 (en) | 2016-03-30 |
JP6018700B2 (en) | 2016-11-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2017041481A1 (en) | Display device | |
US9103566B2 (en) | Solar light collecting device and solar heat collecting facility | |
CN102156340B (en) | High-precision pose adjusting device for spliced grating | |
US20130269753A1 (en) | Mounting assemblies, solar trackers, and related methods | |
CN110095338B (en) | Test fixture | |
CN106965420A (en) | A kind of open 3D printer based on cold printing | |
US20160040910A1 (en) | Sunlight concentrating apparatus | |
CN102803861A (en) | Concave reflecting mirror for heliostat, and method for manufacturing the concave reflecting mirror | |
US8596802B2 (en) | Adjustable reflector for directing energy to a receiver | |
AU2011295296A1 (en) | Mirror module | |
CN102574341B (en) | Method for shaping a reflector | |
CN110170786A (en) | U-shaped rib assembling system | |
US7810940B2 (en) | Adjustable table for shaping a mirror | |
CN113075781B (en) | Large-area heliostat supporting structure | |
EP3190353A1 (en) | Solar collector | |
CN206884171U (en) | A kind of open 3D printer based on cold printing | |
CN208269436U (en) | A kind of mirror surface frame and tower photo-thermal power generation settled date mirror holder | |
CN111794903B (en) | Device and method for aligning a plurality of beams of spar caps of a wind turbine blade | |
CN110068908A (en) | A kind of heliostat mirror holder | |
CN209705558U (en) | Mirror frame structure and heliostat | |
CN214459558U (en) | Compensating device for beam bridge running gear | |
CN219688315U (en) | Auxiliary device convenient for adjusting carrier roller assembly | |
CN109530486B (en) | F shaped steel roll formula low temperature orthotic devices | |
CN219052707U (en) | Back stop linear guide rail adjusting device for bending machine | |
JP6066800B2 (en) | Solar concentrator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: HITACHI ZOSEN CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ASHIDA, SATOSHI;MA, DONGHUI;REEL/FRAME:037367/0780 Effective date: 20151009 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |