Optical characterisation and optimisation of a static Window Integrated Concentrating Photovoltaic system

In this work, three different geometrical properties have been considered to develop a new solar concentrator design for Window Integrated Concentrating Photovoltaic (WICPV). They are (i) elliptical entry aperture; (ii) hyperbolic profile section and (iii) square exit aperture. Due to the increasing demands for stationary solar concentrators for building integrated photovoltaic (BIPV), this new design focuses on the use as a stationary solar concentrator. The complete optical analysis of the concentrator is carried out via 3-D ray trace technique. The analysis is based on all necessary design parameters, i.e., elliptical entry axis, concentrator height and the exit aperture geometry, in order to obtain the optimal overall optical performance of the new 3-D solar concentrator. Four different geometrical low concentration ratios were investigated: 4×, 6×, 8× and 10×. Results of the computer simulation show that the designed concentrator of 4× concentration ratio gives the higher optical efficiency of 68% compared to the other low concentration ratios. The 6×, however, gives a higher optical concentration ratio, despite having a lower optical efficiency (55%) than the 4×. A prototype of the designed concentrator was manufactured and tested under indoors conditions. The experimental results have shown an agreement by a difference of 5% with the simulation results. These results highlight how different factors need to be taken into consideration when carrying out optimisation studies. Overall, the proposed concentrator looks promising with sound results to confirm its performance and validate it as a stationary solar concentrator and thereby promote its use in WICPV.

► A novel static solar concentrator designed: Square Elliptical Hyperboloid, SEH. ► The geometrical profile of the SEH was optimised for a low concentration ratio. ► The SEH has a large acceptance angle of 120° allowing 8 h of sun collection. ► A prototype of the SEH was made and tested in indoors conditions. ► The experimental results validate the optical model.