Rotating Prism Array for Solar Tracking

Abstract

Solar energy has become one of the most promising renewable energies being the most widespread used nowadays. In order to achieve an optimum performance, both photovoltaic and solar thermal applications require the use of some kind of solar tracking technique. Every solar concentration system has to constantly reposition itself according to the Sun's position changes throughout the day. This movement must be done in the most effective way as possible to avoid a high negative impact on the system efficiency.The present paper attempts to describe in detail the design process of a state-of-the-art semi-passive solar tracking concentrator (SPSTC) in which, in order to track the sun, two independent arrays of acrylic prisms are implemented to refract sunlight by rotating said prisms, thus being able to redirect solar radiation as desired. The first set of PMMA prisms is responsible of eliminating one of the directional components of the solar radiation; the task is achieved by rotating the prisms within the array at a specific angle. The second set of “refractive heliostats” deals with another of the sunlight's directional components, transforming its direction into a completely perpendicular pattern to the array. Having downward vertical radiations makes possible to implement a stationary Fresnel lens to concentrate the solar radiation for any application desired.The system is designed and validated using simulation software to prove the feasibility of the concept.