Previous studies on vertical bifacial photovoltaic systems have explored ground sculpting, horizontal reflectors, and mirror assisted configurations; however, a controlled experimental comparison between symmetric flat and parabolic reflector geometries under tropical conditions remains limited. This study experimentally evaluates dual side flat and parabolic reflectors integrated symmetrically on a vertical bifacial module across multiple tilt angles. A geometric optical model based on angle of incidence and irradiance coverage length is validated using measured irradiance, surface temperature, power, and fill factor data. The optimized flat configuration S1-30 achieves 887 W/m 2 mean irradiance and 264 W mean power, outperforming the best parabolic case S2-30 at 249.73 W despite higher irradiance of 932.76 W/m 2 in the latter. Midday irradiance increase from 554 to 1067 W/m 2 in flat systems results in proportional power rise from 153 to 254.5 W, whereas parabolic reflectors show non proportional gains due to mismatch and thermal concentration effects. Strong irradiance power correlation is observed in S1 with R 2 values of 0.90 to 0.94 up to 30° tilt, while S2 shows reduced proportionality and higher thermal sensitivity with R 2 of 0.75 to 0.82, confirming that reflector geometry governs optical thermal coupling and electrical conversion efficiency under tropical outdoor conditions.
Shaikh et al. (Thu,) studied this question.