Design and construction of a solar tracking device.

Abstract

The major output of the project was to determine the energy and financial gain achieved in tracking the sun’s position when collecting solar energy versus having fixed tilt solar collectors. The use of solar energy as an alternative clean source of power has been limited because of low solar cell conversion efficiency and relatively expensive tracking devices and yet demand for energy continues to rise. The goal of this project was to design and construct a device that orients solar collectors towards the highest irradiation by; designing and constructing the mechanical part and designing an algorithm and electrical-control system based on time. The mechanical system was designed in Solid Works, and thereafter constructed with a car window worm gear system having a gear ratio of 70. The electrical-control system employed a stepper motor and an L298N motor driver, an SD card module and Real Time Clock module, two voltage regulators (the LM7805 and the LM2596), and an Arduino microcontroller in which the time based (chronological) algorithm was implemented in the Arduino C program to achieve the motion of the motor and subsequently the collector’s angular velocity of 15°/ℎ. The mechanical and electrical control system achieved tracking for 16 days without failing, and results obtained show that indeed there is a daily gain in power collected of 19.1 % when solar modules are oriented towards the sun during the day. It was also shown that a worm gear system with a stepper motor saved 73.5 % of electrical power and the only challenges experienced were in current measurement with the ACS-712 current sensors that led to relatively low quality results with some days of data being completely eliminated during analysis. The NPV of the system designed and constructed, which was calculated for tracking and static systems to be UgShs (521,051) and UgShs (61,388) respectively, indicated that the project is not financially feasible in the timeline of 25 years considered although it could be possibly found feasible if the project scaled up, and economies of scale used. For one who desires to work on the same or a similar project, better methods of current sensing e.g. shunt resistors, implementation the electrical control system on a Printed circuit board and a microcontroller chip instead of the board, and inclusion of an inclinometer to provide feedback, and thus improve the accuracy of the system should be considered.