Heliostat orientation system using a PLC based robot manipulator

Abstract

Solar energy reaching a given surface depends directly on sun's orientation and sensor's position. Concentrated solar power systems are using sun-tracking heliostats to reflect maximum solar heat to a thermal receiver mounted atop a central power tower. The focused heat boils water within the thermal receiver and produces steam to supply a turbine for power generation. Since sun's rays are constantly variable throughout a day one should constantly change the position of the heliostat using an orientation system. First, a program for calculating the daily, monthly and yearly position of the sun for any earth place is developed using MATLAB software. Then an orientation system based on a robot manipulator in order to allow the heliostat to move for sun's radiation tracking is proposed and described. The results show that this system allows accurate positioning and gives a higher solar energy yield in comparison to a fixed one. Each heliostat will be equipped with this system. For accurate and instantaneous automatic control of the robot manipulator a Programmable Logic Controller (PLC) is used. Satisfying simulation results have been obtained.