Non-tracking solar concentration performance of triangular pyramid shape with mirrors

Abstract

This study proposes a photovoltaic(PV) module which is in the shape of triangular pyramids consisting of flat mirrors and PV cells. The mirrors provide not only solar concentration but also sun tracking function even though the module is fixed. It is expected to have the effects of increasing solar collection on to the cells and reducing installation area because the modules will be set on the ground without any space between them. The objectives of this study are to evaluate the performance of the proposed module in terms of annual solar collection and to derive appropriate design of the pyramid shape. Ray-tracing simmulation was employed to analyze the effect of the triangular pyramid design. Two kinds of index were defined, that is, solar collection per cell area and that per installation area. The results show that it is possible to find out the design cases to increase both indexes compared with a conventional PV panel setting. It is also found that there is pareto optimum set which gives the best performances with trade-off relationship between the two indexes. According to the results, the solar collection per cell area can be improved by 25% while that per installation area by 55% at the maximum. The strategies to design appropriate triangular pyramids were derived from the pareto optimum set. Another design strategy was also examined, which enhances the solar collection especially in the morning and late afternoon. Some design cases achieve the improvement in such point of view, which verifies the ability of sun tracking with fixed structure of the proposed module.