An improved power free tracking system for box type solar cookers

An improved power free solar tracking system for box type solar cookers, suitable for up to six hours of cooking is being reported in this brief note. The requirement for solar tracking along the altitude has been eliminated by orienting a relatively larger booster mirror at a predetermined optimum angle for the day for a particular location. The requirement for tracking along the azimuth has been addressed by using the gravitational potential energy stored in a water container connected to a pair of springs. Discharge of water from the container at a constant predetermined rate drives a timing belt mounted wooden disc to rotate with the sun at a uniform rate. Experimental results indicate that the system faithfully tracks the sun for up to six hours, starting 3 h before solar noon and up to 3 h after it.