Solar Trackers Using Spherical Mechanisms

Abstract

Abstract The power harvesting from a solar panel is maximized when its face is perpendicular to the solar ray. In order for a solar panel to face the sun during the daytime, its orientation has to be adjusted by a solar tracker. There are two relative motions between earth and sun. Compared with its daily east to west rotation, sun’s south-north movement is much smaller. If only sun’s east-west relative motion is considered for developing solar trackers, mechanisms with single degree of freedom can be adopted. If the orientation of a solar tracker with single degree of freedom is adjusted seasonally or monthly to cover sun’s small south-north relative movement, the solar tracker can effectively fulfill its solar tracking function. Single-axis solar trackers commonly consume less power to operate than their two-axis counterparts and cost less to fabricate and maintain, which brings their solar tracking merits. This research is on single-axis solar tracking mechanisms that are based on four-bar mechanisms. Because of their simple structure, high reliability, and easy maintenance, four-bar mechanisms have been extensively employed for various applications that include solar tracking. Four-bar solar tracking mechanisms currently have room for further improvement. The difficulties facing them include limited solar tracking motion, high solar tracking power consumption, and lacking self-locking function. Surmounting these difficulties makes designing four-bar solar tracking mechanisms challenging. Four-bar solar tracking mechanisms can be planar 4R, planar 3R1P, spherical four-bar mechanisms. Each of the three types has its unique solar tracking features. In this research, the performances of these four-bar solar tracking mechanisms are analyzed, simulated and compared with the motivation of improving them. The research results are tried to provide some guidelines for developing and promoting four-bar solar trackers.