Solar Trackers Using Six-Bar Linkages

Abstract A solar panel faces the sun or has the solar ray normal to its face to enhance power reaping. A fixed solar panel can only meet this condition at one moment. A solar panel’s orientation has to be adjusted in order to meet this condition during the daytime. A solar tracker is integrated with a single or a set of solar panels to make them better meet the condition and improve their solar power reaping. In addition to extra cost and maintenance, a solar tracker consumes power when it adjusts the orientation of its related solar panels. Only when the net power gaining from a set of solar panels that have their integrated solar tracker is considerably above that from the same set of solar panels without their solar tracker, it is then worthwhile for the solar tracker to be integrated with the solar panels. A solar tracker needs to have at least two degrees of freedom to make its solar panels face the sun during the daytime since there are two independent relative motions between earth and sun: rotation and revolution. If earth is considered as being stationary for developing solar trackers, sun then has its daily east-west rotation and yearly north-south tilting. It is evident that the sun’s east-west motion on any day is well above its north-south one. If the small north-south daily tilting is ignored for solar tracking, single-axis solar tracks have their advantages over two-axis or multi-axis counterparts because of relatively simple structure and low power consumption. A compromise among the current four-bar single-axis solar trackers is between solar tracking oscillation and self-locking function. Planar 4R solar trackers are capable of producing large solar tracking oscillation, but they lack self-locking function. On the other hand, planar 3R1P solar trackers have self-locking function, but they are incapable of producing large solar tracking oscillation. This compromise is surmounted by the 6R1P six-bar solar trackers that are studied in this research. They can not only generate reasonably large solar tracking oscillation, but also have self-locking function. The disadvantage of six-bar solar trackers is their structural complexity when compared with four-bar solar tracking counterparts. Six-bar solar tracking linkages are investigated in this research. Their solar tracking motion performance is analyzed. This research aims at improving single-axis solar tracking linkages.