JP2012252299A - Heliostat system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heliostat system, even when reflected light from a mirror is deviated from a sensor, capable of training the reflected light on the sensor again.SOLUTION: The heliostat system reads a rotation angle of a mirror 5 at a time same as a time in a latest operating date from storage means, and outputs it to a heliostat 2. There is no difference in the movement trajectory of the sun S viewed from the heliostat 2 for a difference in several days, so that, when the mirror 5 is set to a state in the same time thereto, the sunlight L reflected by the mirror 5 is applied to a sensor 8 to make the sensor in a light receiving state.

Description

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

  In order to effectively use sunlight, a system is known in which the mirrors of a plurality of heliostats are simultaneously controlled while tracking the sun, and the sunlight reflected by the mirrors is collected on a target.

  A sensor is provided on a straight line connecting the mirror and the target of each heliostat. A light receiving element is provided inside the sensor. When the light receiving element receives sunlight, the sensor feedback-controls the mirror of the heliostat so as to maintain the light receiving state. By doing so, the heliostat can always reflect sunlight toward the target while tracking the sun (see, for example, Patent Document 1).

Japanese Patent No. 3784221

  However, in such conventional technology, once the sensor has received the sunlight from the mirror, it can continue to reflect the sunlight toward the target while maintaining the light receiving state. If, for some reason, sunlight from the mirror deviates from the sensor, the mirror cannot be controlled by the sensor, and sunlight cannot be directed to the target.

  The present invention has been made paying attention to such a conventional technique, and provides a heliostat system capable of directing reflected light to a sensor again even if reflected light from a mirror is detached from the sensor. It is aimed.

  The invention according to claim 1 is arranged on a straight line connecting a mirror and a target, a heliostat having a mirror that is rotatable in an azimuth direction related to the diurnal motion of the sun and an altitude direction related to the seasonal motion. A sensor that feedback-controls the rotation of the mirror to receive reflected sunlight and maintain the light-receiving state, a pyranometer that measures the amount of solar radiation around the heliostat, and the day before the azimuth and altitude directions of the mirror Storage means for storing the rotation angle on the working day of the vehicle, and when the amount of solar radiation is detected at a predetermined value or more and the sensor is not receiving sunlight reflected by the mirror, Control means for reading the rotation angle in the azimuth direction and altitude direction of the mirror at the time and outputting it to the heliostat.

  According to a second aspect of the present invention, there is provided solar constant speed tracking means for changing the rotation angle in the azimuth direction and the altitude direction of the mirror of the heliostat at a constant speed according to the moving speed of the sun when the solar radiation amount is less than a predetermined value. It is characterized by being.

  According to the first aspect of the present invention, the memory is stored in the case where the reflected light from the mirror is not in the light-receiving state even though the solar radiation meter detects the amount of solar radiation of a predetermined value or more. The rotation angle of the mirror at the same time on the most recent working day is read from the means and output to the heliostat. Since the movement trajectory of the sun as viewed from the heliostat is different if it is a difference of several days, if the mirror is set at the same time, the sunlight reflected by the mirror hits the sensor and enters a light receiving state. In this way, even if the reflected light from the mirror comes off the sensor, it can be returned to the sensor side again, so that the heliostat can reliably and continuously reflect sunlight toward the target.

  According to the second aspect of the present invention, when sunlight is blocked by clouds or the like, the mirror can be rotated at a constant speed according to the moving speed of the sun. By doing so, when there is no cloud and sunlight is revived, the rotation angle of the mirror is almost in the normal position with respect to the sensor, and the mirror can reflect the sunlight as it is and hit the sensor.

The whole perspective view which shows the state which has reflected sunlight toward the target with a heliostat. The perspective view which shows a heliostat. The perspective view which shows a sensor. Sectional drawing of the box in alignment with the arrow SA-SA line in FIG. Sectional drawing of the box which follows the arrow SB-SB line | wire in FIG. Explanatory drawing which shows the structure of a sensor. The rear view which shows the state which is reflecting sunlight toward a sensor from a mirror. Explanatory drawing which shows movement of the sun and rotation of a mirror. The top view which shows the non-regular light reception state of a sensor. The top view which shows the regular light reception state of a sensor. The block diagram which shows the whole structure. The figure which shows the state from which the reflected light from a mirror has remove | deviated from the sensor. The figure which shows the difference in the movement locus | trajectory of sunlight by a season. The figure which shows reading the memory | storage data of the latest working day.

  1 to 14 are diagrams showing a preferred embodiment of the present invention.

  A plurality of heliostats 2 are arranged around the tower 1. A target 3 is provided at the top of the tower 1, and sunlight L is reflected from the heliostat 2 toward the target 3.

  The heliostat 2 has a square mirror 5 supported by a U-shaped frame 4. The mirror 5 is rotatable in the altitude direction B around a horizontal axis supported by the altitude motor 6 on the frame 4. The mirror 5 can be rotated in the azimuth direction A by the azimuth motor 7 about the vertical axis together with the frame 4. The azimuth direction A is a direction related to the diurnal motion of the sun S, and the altitude direction B is a direction related to the seasonal motion of the sun S.

  Sensors 8 are respectively installed on straight lines connecting the mirror 5 and the target 3. The sensor 8 is installed in a stationary state on the ground.

  The sensor 8 has a circular introduction hole 9 formed on the heliostat 2 side. The introduction hole 9 is covered from the outside with a transparent cover 10 made of resin. A pair of light detection sensors 20a, 20b, 21a, and 21b are arranged on the inner bottom surface of the sensor 8 in an orthogonal cross shape. The two light detection sensors 20a and 20b face each other in the direction X (see FIG. 6) related to the azimuth direction A, and the other two light detection sensors 21a and 21b face each other in the direction Y related to the altitude direction B. is doing.

  A circular spot P of sunlight L introduced straight from the introduction hole 9 is formed at the center of the bottom surface of the sensor 8. In a state where the spot P is at the center of each of the light detection sensors 20a, 20b, 21a, and 21b, the received light amount between the pair of light detection sensors 20a, 20b and 21a, 21b is equal in both the direction X and the direction Y. Outputs from the light detection sensors 20a, 20b, 21a, and 21b are equal. When the outputs of the pair of light detection sensors 20a, 20b, 21a, and 21b are equal, no signal is output from the control means 11 to the altitude motor 6 and the azimuth motor 7. This state is the normal light receiving state of the sensor 8 (see FIG. 10). In the case of the regular light receiving state, sunlight L reflected at the center of the mirror 5 is introduced into the sensor 8 through the introduction hole 9.

  When the spot P of sunlight L from the introduction hole 9 is shifted from the center and the outputs of the light detection sensors 20a, 20b, 21a, and 21b are different (see FIG. 9), the control means 11 detects the state. Then, a signal is sent to the altitude motor 6 and the azimuth motor 7, and the mirror 2 of the heliostat 1 is rotated to correct the uneven state of the output.

  By such feedback control of the sensor 8, the mirror 5 can continuously reflect the sunlight L toward the sensor 8 side (target 3 side) while tracking the sun S.

  A pyranometer 12 is provided around the heliostat 2. This pyranometer 12 is for detecting whether the incident sunlight L has sufficient energy. For example, when the sunlight L is blocked by a cloud or the like, the control by the sensor 8 cannot be performed. In this case, the solar constant speed tracking means 13 switches to the solar constant speed tracking mode. The solar constant speed tracking mode is to change the rotation angle of the mirror 5 of the heliostat 2 in the azimuth direction and the altitude direction at a constant speed according to the moving speed of the sun.

  Therefore, even when the feedback control of the sensor 8 is not activated, the mirror 5 can be rotated at a constant speed according to the moving speed of the sun. Then, when there is no cloud and the sunlight L is revived, the rotation angle of the mirror 5 is almost in the normal position with respect to the sensor 8, and the sunlight 5 is reflected by the mirror 5 as it is. 8 can be applied. When sunlight L hits the sensor 8, feedback control is activated.

  Next, as shown in FIG. 12, the reflected light from the mirror 5 is detected from the sensor 8 for some reason, even though the solar radiation meter 12 detects the amount of solar radiation greater than a predetermined value and the solar constant speed tracking mode is differential. It may come off. In that case, the rotation angle of the mirror 5 at the same time on the most recent working day is read from the storage means 14 and output to the heliostat 2.

  That is, the movement trajectory of the sun S can be predicted by the season and time as shown in FIG. 13, but in this embodiment, the actual rotation angles in the azimuth direction A and altitude direction B of the mirror 5 controlled by the sensor 8 are determined. This is stored in the storage unit 14. Then, the rotation angles in the azimuth direction A and the altitude direction B of the mirror 5 at the same time on the latest working day are read and output to the heliostat 2. In the present embodiment, as shown in FIG. A non-working day is a day in which operation was not possible throughout the day due to rain or the like, and the other days are working days. A clock function may be added separately, but a clock function such as an RTC built in the control unit 14 may be used.

  Since the movement trajectory of the sun S viewed from the heliostat is different for several days, the sunlight L reflected by the mirror 5 can be controlled by hitting the sensor 8 if the mirror 5 is set at the same time. It becomes a state. Since the state in which the heliostat 2 has actually operated in the past is stored, not the prediction, the state of the mirror 5 can be reliably restored. Thus, even if the sunlight L from the mirror 5 comes off from the sensor 8, it can be returned to the sensor 8 side again, so that the reliable and continuous sunlight L toward the target 3 by the heliostat 2 is achieved. Can be reflected.

  In the above embodiment, the graticule type heliostat 2 that rotates the mirror 5 in the azimuth direction A and the altitude direction B is taken as an example, but it is an equatorial ritual type heliostat that rotates in the ecliptic direction and the declination direction. May be.

  Although the example which rotates the one big mirror 5 was shown, you may make it rotate the multi-mirror structure comprised by the some mirror.

2 Heliostat 3 Target 5 Mirror 8 Sensor 11 Control means 12 Solarimeter 13 Solar constant speed tracking means 14 Storage means A Azimuth direction B Altitude direction L Sunlight S Sun

Claims (2)

A heliostat having mirrors that are rotatable in an azimuth direction related to the diurnal motion of the sun and in an altitude direction related to the seasonal motion
A sensor that is arranged on a straight line connecting the mirror and the target, receives the sunlight reflected by the mirror, and feedback-controls the rotation of the mirror so as to maintain the light receiving state;
A pyranometer to measure the amount of solar radiation around the heliostat,
Storage means for storing the rotation angle on the working day before the previous day in the azimuth direction and altitude direction of the mirror;
Rotation angles in the azimuth and altitude directions of the mirror at the same time on the most recent working day from the storage means when the amount of solar radiation is detected and the sensor is not receiving sunlight reflected by the mirror And a control means for reading out and outputting to the heliostat.   Solar constant speed tracking means is provided for changing the rotation angle in the azimuth direction and altitude direction of the heliostat mirror at a constant speed according to the moving speed of the sun when the amount of solar radiation is less than a predetermined value. The heliostat system according to claim 1.

Images