A novel stationary concentrator to enhance solar intensity with absorber-only single axis tracking

Abstract

Enhancement of solar intensity is achieved through concentrator which focuses direct normal irradiance to a smaller area. Such redirection necessitates aligned movement of the whole assembly along the apparent motion of the sun. The motion of a bulky system consumes significant power during the operation, thereby reducing the effective energy collection efficiency. Therefore, a static geometry which does not require tracking the sun is desirable as concentrating optics. Here, we propose such a novel static concentrator based on cylindrical Fresnel lens. Only the absorber is given a single axis tracking motion. A systematic optimization is performed to select the geometrical parameters which maximize the solar intensity and minimize the intensity-non-uniformity. For a Silicone glass cylinder of 20 cm diameter, we find an absorber of width 5 cm, placed at a distance of 11 cm from the axis of the concentrator provides the maximum intensity and the minimum intensity-non-uniformity when the vertex angle of the Frensel lens is 37°. The study demonstrates that the procedure to perform such geometry optimization is straightforwardly extendable. We demonstrate that the annual average intensity on the absorber can be enhanced by over ∼50% with lower operational cost and a meagre increase in the initial cost.