Enhancing electrical power output of bifacial photovoltaic modules through low-cost reflective materials: A multi-location experimental study under tropical conditions

The effect of three low-cost reflective materials (aluminum foil, mirror sticker, and white cladding) on the performance of bifacial photovoltaic (PV) modules was investigated in this study under tropical outdoor conditions. A paired experimental setup consisting of two identical 20 W bifacial PV modules was used to test the performance of the reflector-assisted module at two locations in Sri Lanka (Kandy and Kurunegala) with a non-reflective control module. The voltage, current, power, and module temperature were measured every 5 s using a low-cost ESP32-based sensor monitoring system. All reflective materials increased the measured operating voltage, current, and power relative to the paired control under the fixed-load condition, with mean power gains of 56.7–80.5%. The highest average gain was achieved with white cladding in Kurunegala and with aluminum foil in Kandy. The difference is due to the interaction between the optical characteristics of the reflectors and the local environmental conditions. The observed differences are consistent with the interaction between the optical characteristics of the reflectors and local environmental conditions. Diffuse reflection may provide more spatially distributed rear-side illumination, while the higher reflectance of aluminum foil may provide greater rear-side illumination under favorable direct-sunlight conditions. While the irradiance on the back side was not measured directly, the results show that low-cost reflector materials can enhance bifacial PV performance and that the choice of reflector material should be based on site-specific environmental conditions.