JP5462359B2 - Heliostat - Google Patents

Description

  The present invention relates to a heliostat capable of reflecting sunlight and collecting it at one point while tracking the sun.

  In order to effectively use sunlight, a heliostat is known as a light collecting device that simultaneously controls a plurality of mirrors while tracking the sun and collects sunlight reflected by the mirrors at one point. A plurality of mirrors of such a heliostat are rotated in a diurnal direction and a seasonal direction as a group, for example, as exemplified in Japanese Patent Publication No. 3784221, and the respective spots of the plurality of mirrors are superimposed on the target. Can be applied in the state.

  However, in such a conventional technique, although constituted by a plurality of mirrors, since they are rotated as a group, aberrations according to the outer diameter size as a group are generated. In other words, during the daytime when the solar altitude is high, the spots of the mirrors overlap with each other in a substantially circular shape and a substantially circular condensing spot is obtained, but in the morning and evening when the solar altitude is low, the angle of sunlight relative to the mirror is When it becomes smaller, the optical axis of the spot of each mirror shifts and the aberration of the focused spot increases. Therefore, the spot of each mirror deform | transforms into an ellipse shape, and the subject that the condensing spot of the same shape as daytime cannot be obtained arises.

  The present invention has been made by paying attention to such a conventional technique, and provides a heliostat capable of obtaining a condensing spot having the same shape without changing its shape throughout the day.

  According to the technical aspect of the present invention, the heliostat includes a first shaft that is rotatable, a second shaft that is rotatable in a direction orthogonal to the first axis, and a support member that is orthogonal to both ends of the second shaft. A lever that supports one or a plurality of mirrors at both ends of the support member, and enters the second shaft integrally formed with the support member and having a cylindrical structure, the support member being a lever And a cam means fixed to the first shaft and in pressure contact with the tip of the lever, the first member being rotatable about the axis of the support member with respect to the second shaft. When the rotation angle of the mirror related to the shaft is morning or evening, the cam means rotates the lever to change the angle of the mirror in the direction of opening in the rotation direction related to the first shaft.

  According to the present invention, when the rotation angle related to the first axis is morning and evening, the cam means changes the angle in the direction of opening the mirror in the rotation direction related to the first axis. Aberration in the direction can be canceled. When the incident angle of sunlight becomes oblique, the sun light reflected by the mirror crosses in the closing direction and does not collect light at one point, so the sun's altitude is lowered to correct it. Only in the morning and evening, the mirror was rotated in the opening direction. Therefore, even when the solar altitude is low in the morning and evening, in the direction related to the first axis, the spot shape does not deform into an ellipse, and it is easy to obtain a collective spot in which the spots having the same shape as the daytime are overlapped together. Become.

  Further, when the rotation angle related to the second axis is morning and evening, the cam means changes the angle in the direction to open the mirror in the rotation direction related to the second axis, so that the aberration in the direction related to the morning and evening second axis Can be canceled. When the incident angle of sunlight becomes oblique, the sun light reflected by the mirror crosses in the closing direction and does not collect light at one point, so the sun's altitude is lowered to correct it. Only in the morning and evening, the mirror was rotated in the opening direction. Therefore, even when the solar altitude is low in the morning and evening, in the direction related to the second axis, the spot shape is not deformed into an ellipse, and it is easy to obtain a collective spot in which the spots having the same shape as in the daytime are overlapped together Become.

  Furthermore, since the first axis is rotatable in the ecliptic direction and the second axis is rotatable in the declination direction, the sun can be easily tracked.

  In addition, since an encoder, an actuator, and a microcontroller are not used to correct the direction of each mirror 5, and automatic correction can be performed only by a passive mechanism, the reliability is high and the cost is not high.

FIG. 1 is a schematic diagram showing a beam-down type condensing system. FIG. 2 is a perspective view showing a heliostat. FIG. 3 is a schematic view showing a focused spot of the heliostat. FIG. 4 is a schematic view of the heliostat in a direction along the line SA-SA indicated by an arrow in FIG. 3. FIG. 5 is a schematic view corresponding to FIG. 4 in the morning and evening rotation state. FIG. 6 is an enlarged sectional view showing the cam means. 7 is a schematic plan view seen from the direction of the arrow DA in FIG. FIG. 8 is a schematic view of the heliostat in the direction along the line SB-SB in FIG. FIG. 9 is a schematic view corresponding to FIG. 8 in the morning and evening rotation state.

  1 to 9 are diagrams showing a preferred embodiment of the present invention. FIG. 1 shows a beam-down solar concentrator. In the center, an elliptical mirror 1 is installed in a downward state at a predetermined height by a support tower (not shown). The elliptical mirror 1 has a mirror surface that is part of a spheroid, and has a first focal point A and a second focal point B below it. Below this elliptical mirror 1, a heat conversion device 2 for converting sunlight L into heat energy is installed. Above the heat conversion device 2, a tapered cylindrical condensing mirror 3 is installed. Has been. A large number of heliostats 4 are provided on the ground around the heat conversion device 2 so as to surround the elliptical mirror 1.

  Each heliostat 4 is controlled in posture so as to always direct the sunlight L toward the first focal point A while tracking the sun S. If the sunlight L reflected by the heliostat 4 passes through the first focal point A, the sunlight L is reflected downward by the elliptical mirror 1 and is always collected at the second focal point B and passes through the condensing mirror 3. Then, the heat conversion device 2 is reached.

  In order to introduce the sunlight L reflected by the elliptical mirror 1 into the narrow condenser mirror 3, the sunlight L reflected by the heliostat 4 needs to be collected by a small spot having the same shape. Therefore, the heliostat 4 in this embodiment has a small structure with four mirrors 5.

  Next, the structure of the heliostat 4 will be described. The base 6 is provided with a bar 7 on the south side and a sensor 8 at the upper end. A support column 9 is provided on the north side of the base 6, and a first drive unit 10 is provided on the upper end thereof. The first drive unit 10 is provided with a first shaft 11 that is parallel to the rotation axis of the earth and has a predetermined angle with respect to the ground. The first shaft 11 is freely rotatable in the ascending direction X around the axis by the first drive unit 10 (see FIG. 3).

  A U-shaped frame 12 is fixed to the tip of the first shaft 11. The frame 12 is small in size, and a second shaft 13 having a cylindrical structure passes through the flanges on both sides thereof in a direction orthogonal to the first shaft 11. Specifically, the second shaft 13 is a metal pipe having a predetermined diameter, and both sides protrude to the outside of the flange. Between the frame 12 and the second shaft 13, a second drive unit 14 that rotates the second shaft 13 with respect to the first shaft 11 is provided.

  Support pipes 16 penetrate through the second shaft 13 projecting outward from the frame 12 through another frame 15 in the orthogonal direction. The second shaft 13 and the support pipe 16 form an overall H shape, and circular mirrors 5 are attached to both ends of the support pipe 16 at the four corners by brackets 17 that are rotatable with respect to the support pipe 16, respectively. The mirror 5 has a diameter of 50 cm and the mirror surface is a concave spherical surface. The effective focal length of the mirror 5 is set to the distance to the first focal point A of the elliptical mirror 1, respectively.

  A pair of sensor mirrors 18 is provided on the second shaft 13 inside the frame 12. The sensor mirror 18 is a horizontally long rectangle having a horizontal dimension of 30 cm and a vertical dimension of 20 cm.

  The sunlight L reflected by the sensor mirror 18 is received by the sensor 8. The sensor 8 is located between the sensor mirror 18 and the first focal point A, and the first focal point A exists on the extended line connecting the sensor mirror 18 and the sensor 8. Therefore, if the attitude of the mirror 5 is controlled so that the sunlight L from the sensor mirror 18 always goes to the center position of the sensor 8, the reflected sunlight L will surely go to the first focal point A beyond the sensor 8. Become. As described above, the sunlight L toward the first focal point A is reflected by the elliptical mirror 1 and always reaches the second focal point B.

  The directions of the four mirrors 5 are adjusted in advance so that the reflected lights of the mirrors 5 overlap each other as a condensed spot P at the first focal point A at the time of south and middle (see FIG. 3). That is, the aggregate of the four mirrors 5 can be regarded as one virtual spherical mirror. Furthermore, it is required that the condensing spot P is small at the first focal point A and that the shape does not deform during the day's operation. This is because, when the shape of the focused spot P is deformed and spherical aberration is generated, reflected light that deviates from the receiver of the thermal conversion device 2 that is the final focused section is generated.

  An outer cylinder portion 19 is provided outside the frame 12 of the second shaft 13. The outer cylinder portion 19 is slidable only in the longitudinal direction with respect to the second shaft 13 and is urged toward the first shaft 11 by a spring (not shown). The first shaft 11 is provided with a cam plate 20 whose position is fixed to the main body of the first driving unit 10 and the column 9. A cam follower 21 integrally formed with the outer cylinder portion 19 is in pressure contact with a spring (not shown). The cam surface of the cam plate 20 defines a curved surface having a curvature larger than that of the arc, and when the first shaft 11 is greatly rotated in the meridian direction X, that is, in the morning and evening, the cam follower 21 is placed outside (the first shaft 11 It is structured to push toward (radial direction). Another cam surface 22 is also formed on the end surface of the outer cylinder portion 19.

  In addition, a lever 23 that rotates integrally with a support pipe (support member) 16 is provided in the second shaft 13, and a cam follower 24 that presses against the cam surface 22 is provided at the tip thereof. The lever 23 is biased by a spring 25 in a direction in which the cam follower 24 is pressed against the cam surface 22.

  A rod-like cam bar 26 is connected to the brackets 17 at both ends of the support pipe 16. Each cam bar 26 is connected by a cam follower 27. A cam surface 28 is fixed to the second shaft 13 (the outer surface of the outer cylinder portion 19). The cam follower 27 is pressed against the cam surface 28 by urging means (not shown). The cam bar 26 is disposed in parallel to the position offset from the support pipe 16, and the connecting portion between the cam bar 26 and the bracket 17 is also offset from the support pipe 16 (not shown). The cam surface 28 has a substantially elliptical curved surface as shown in FIG. 8, and when the second shaft 13 is largely rotated in the declination direction Y, that is, in the morning and evening, the cam follower 27 is pushed outward, and the cam bar 26 is It has a structure that pulls inward.

  The curved surface shape of the cam surface of the cam plate 20 and the curved surface shape of the cam surface 28 can be appropriately set based on the mirror surface shape of the mirror 5, the positional relationship between the heliostat 4 and the first focal point A, the altitude of the sun, and the like. .

  Next, the operation will be described. When the mirror 5 rotates about the first axis 11 in the red meridian direction X, the condensing spots P of the four mirrors 5 are all substantially circular and overlap each other during the daytime. In the morning and evening, when the position of the sun S is lowered, the spot has become elliptical in the ecliptic direction X due to aberration, but according to this embodiment, the spot became morning and evening as shown in FIG. At this time, the cam follower 21 is pushed by the cam plate 20 to push the outer cylinder portion 19 outward. Then, the change of the cam surface 22 of the outer cylinder portion 19 and the cam follower 24 of the lever 23 causes the lever 23 to rotate together with the support pipe 16 to rotate the mirror 5 in the opening direction, thereby correcting the optical axis of the mirror 5. . Therefore, even in the morning and evening, the shape of the condensing spot P does not deform into an ellipse in the red longitude direction X. Conventionally, the reflected light from each mirror 5 intersects each other inward because of the spherical aberration of the mirror 5 constituting a part of one virtual spherical mirror, so that the focused spot P is deformed into an ellipse. It was. On the other hand, in the present invention, the mirrors 5 are corrected in the direction to open each other to cancel the deviation of the optical axes, so that there is no crossing of the reflected light and the light is condensed at one point of the condensing spot P. . In other words, this corresponds to the fact that the virtual spherical mirror can be deformed into an aspherical shape under the condition that the spherical aberration increases.

  Similarly, in the declination direction Y, as shown in FIG. 9, the bracket 17 is pulled by the cam bar 26 and rotates together with the mirror 5 due to the positional change between the cam follower 27 and the cam surface 28 of the cam bar 26. Even in the morning and evening, the shape of the focused spot P does not deform into an ellipse in the declination direction Y.

  In this way, the shape of the focused spot P is not deformed in both the ecliptic direction X and the declination direction Y, and the solar spot is always overlapped as one circular focused spot P, so that solar heat can be easily used.

  In the above description, a four-sheet heliostat in which one mirror 5 is provided at each end of the two support pipes 16 is taken as an example, but a plurality of mirrors 5 are provided at both ends of the support pipe 16. , 8 or 10 heliostats may be used.

  Moreover, although the circular shape of diameter 50cm was taken as an example as the mirror 5, it is not limited to this, A diameter other than 50cm may be sufficient and it does not need to be circular.

  Moreover, although the example of the beam down type solar condensing device was shown, the heliostat 4 of the present invention can also be used for a tower type solar concentrating device.

(US designation)
This international patent application is related to the designation of the United States, and Japanese Patent Application No. 2010-99016 filed on April 22, 2010 (filed on April 22, 2010) is prioritized under Section 119 (a) of the United States Patent Act. Incorporate the interests of the right and cite the disclosure.

Claims (3)

A first shaft rotating freely, a second shaft can freely rotate in a direction orthogonal to the first axis provided to pass through the support member perpendicular to the ends of the second shaft, at both ends to multiple respective said support member A heliostat supporting a mirror,
A lever that is integrally formed with the support member and enters the second shaft having a cylindrical structure, the support member being rotatable about the shaft center of the support member with respect to the second shaft via the lever. With some
A cam plate fixed to the first shaft and in pressure contact with the tip of the lever;
When morning evening, the cam plate rotates the lever, heliostats, characterized in that to an angle changes in a direction of opening to each other mirror in the direction of rotating about the first axis. A first shaft rotating freely, a second shaft can freely rotate in a direction orthogonal to the first axis provided to pass through the support member perpendicular to the ends of the second shaft, at both ends to multiple respective said support member A heliostat supporting a mirror,
A cam portion fixed to the second shaft;
A bracket provided integrally with a mirror at both ends of the support member and rotatable around the second axis;
A cam follower connected to the bracket, which is in pressure contact with the cam portion;
When morning evening, the cam follower rotates the bracket, heliostats, characterized in that to an angle changes in a direction of opening to each other mirror in the direction of rotating about the second axis.   The first axis is parallel to the rotation axis of the earth and is rotatable about the axis in the ecliptic direction related to the diurnal motion of the sun, and the second axis is the declination direction related to the seasonal motion of the sun. The heliostat according to claim 1 or 2, wherein the heliostat is rotatable.

Images