Modelling and experimental analysis of low concentrating solar panels for use in building integrated and applied photovoltaic (BIPV/BAPV) systems

Geometrically equivalent V-trough and compound parabolic concentrators (CPC) were simulated to characterise the variation in optical efficiency using ray tracing modelling with COMSOL Multiphysics. The effect of CPC truncation and V-trough side wall angles were studied. The truncated CPC demonstrated much improved light acceptance outside the designed angle of acceptance when compared to the original CPC design and V-trough-like characteristics past the original design acceptance angles, consequently reducing material consumption for the manufacture of truncated CPC and therefore reduction in the cost of the system. Truncated CPCs showed optical efficiency equal to their full height counterparts, but a lower concentration ratio (4 at full, 3.6 at half and 2.7 at 50 mm height) due to an equivalent reduction of the inlet aperture size. The V-trough had a higher optical concentration ratio over 15–30° angle of incidents (AoI), with the CPC taking over from 30° AoI upwards. Experiments were performed on a 50 mm truncated CPC and a 22° Trough Wall Angle (TWA) V-trough collector under outdoor conditions. Experimentally measured data showed good correlation with ray tracing simulation results. Both experimental and the ray tracing analyses showed the CPC concentrator achieving a 2.4% higher power output compared to the V-trough design.