Development of High Temperature Solar Collector

Abstract

In the first year of the solar furnace project, we modified the old solar furnace built at the Department of Physics by replacing the support for the 4m x 3m flat mirror (heliostat) used to track the sun. The support consisted of three main parts: the hinge attached to the mirror to allow the mirror to move in the up-down direction, the vertical axle to allow the mirror to move in the left-right direction, and the base. Since the previous support used a small diameter (about 3.8cm) vertical axle with a length of only about 30cm, and galvanized steel pipe for the base which was not heavy, the old support was unstable, wobbly and not tall enough. When the mirror was lowered to a small altitude, the mirror hit the floor. Rotation in the left-right direction was by rotating the axle with the help of angular contact ball bearings (7004-B-TVR: d = 20 mm). The new support was designed to be taller, with an axle of 1.5m attached to a non-rotating base. The rotating part was the outer cover of the axle. The angular contact ball bearings were improved to be tapered bearings for the top and bottom bearings for freer motion. Boots made from Superlene Nylon6 were used around the axle to ensure the axle remained central in the outer cover. The base was made from thicker steel plate and a concrete slab added to make the mirror more stable. The axle attached to the back of the mirror, to allow it to rotate in the up-down direction, was also improved. The new support for the mirror was much stronger and stable. In addition, the motor used to rotate the mirror in the left-right direction was changed to one that was more powerful than the previous one. Testing showed that the mirror moved more easily in both the up-down and left-right directions and was more stable.