The sun tracking control system based om sun position calculation using microcomputer.(Thai)

Abstract

This research presents a sun tracking control system based on sun position calculation using a microcomputer. The advantages of this system are that it can be operated under a low intensity of daylight and has low maintenance requirements because it does not use a photo sensor. This system consists of equipment for two axis independent movement which can track the sun’s position both in altitude and azimuth. The components for each axis consist of dc motor, driver, position sensor and digital controller. The procedure for the system operation is as follows. First, calculate the sun’s position in altitude and azimuth based on the geographic coordinate, date and time. After that, read the present altitude and azimuth angles from the system and compare with the angle value from calculation. This error is the control signal for controlling the system through the motor of each axis. This system is installed on the 5th floor of the Faculty of Engineering Building at Mahasarakham University. To test the system the total radiation was measured using two pyranometers. These pyranometers are installed on the sun tracking system and on a fixed surface at 15 degrees. The results show that the total radiation measured by the pyranometer on the sun tracking system is higher than the pyranometer which was installed on the fixed surface with an average value of 28.42%. In conclusion the proposed sun tracking system works well, because the results indicate that the measured collected solar energy on the moving surface is significantly higher than on the stationary surface. This control system can be applied for solar collectors to significantly improve efficiency.