Operation of two – axis solar tracking by the discharge of water from a tank hanging by a non - circular sprocket wheel

Abstract

Two-axis solar tracking system operated by the discharge of water from a bottom hole of a tank filled with water was designed, constructed and tested. The water tank is hanged by a chain passing over a non-circular sprocket wheel which is fixed to the rotating shaft along the first solar tracking axis. A counterweight is also hanged by another chain passing over a regular circular sprocket. In the morning, the tank is full and the water tank and the counterweight on either side of the shaft balance in such a way that the solar panel is facing the East as required. This study shows that the contour of the non-circular sprocket wheel can be designed taking into consideration the reduction of weight of water tank with time and the required rotation for solar tracking. In addition to the hourly tracking by the above mechanism, provision has been made to tilt the second tracking axis of the solar panel manually on a weekly basis to compensate for the seasonal variation of the Sun's declination. Results show that the additional cost involved in making this mechanism is justifiable when considering the increase of about 30% of more solar power obtainable by two-axis tracking. The paper published regarding this tracking system at Sri Lanka Association for the Advancement of Science (SLAAS) in 64th Annual Sessions held on 01-06 December 2008 shown in Appendix A.