A novel design concept for a reflector of parabolic trough concentrator based on pure bending and correction principle

It is cost effective to manufacture a reflective surface of a solar parabolic trough concentrator in a parabolic cylinder shape by pure bending of a flat sheet. However, the surface manufactured by such an elastic bucking is only a coarse approximation of a parabola, which is not precise enough for meeting the demand of a high quality concentrator. A novel design concept was proposed to remove this error by applying an external force on both edge of a sheet, together with two additional forces: the edge torsion force and the pressing force. The optimal position and magnitude of two additional forces were figured out among various conditions, thereby a theoretically maximal concentration ratio up to 115 was found. Prototypes and engineering realizations of this method were also presented. This method provides a very attractive approach for low cost and high efficiency solar energy solutions.