Increase of solar harvest time with a double static concentration refractive-reflective system

Abstract

In static solar devices, the acceptance angle is limited by the entry angle and the sun movement. Hence, the solar harvesting time in them is short. To increase the collection time it is usually necessary to sacrifice the concentration factor. Several investigations have been made to increase the solar harvest time. Some of them using a primary and secondary optical system with different degrees of complexity in the optical devices. In this work, a new design, a double static concentrating system to increase the solar harvesting time is presented, Its performance is analyzed using CAD simulation. The device is based on a funnel type reflective concentration system as a secondary optical element with an on-top prism as primary optics. The device shows an acceptance angle of 60° with an effective maximum concentration factor of 3.3X. The mean optical efficiency is of 66%, having its best performance for incidence angles between $\pm 41.25^{\circ}$, allowing 5.5 hours of use. Furthermore, the design has the additional benefit of its ease to build.