Experimental Analysis of the Old Solar Module Performance Degradation under Outdoor Weather Conditions in Bangladesh: A Visual and Electrical Investigation

This research investigates the performance degradation of six 10-watt photovoltaic (PV) modules after five years of exposure to the humid climate of Bangladesh. Employing a comprehensive approach, the research conducted visual and electrical analyses to provide a holistic understanding of the modules’ conditions. Visual inspection, involving top and rear views, revealed various degradation factors, including discoloration, delamination, back sheet damage, corrosion, and dust and soiling. Simultaneously, electrical performance was evaluated using an I-V tracer outdoors, and experimental results demonstrated the degradation of the modules over time. A 9.614-watt maximum and a 5.665-watt minimum output power were found for the old PV panel. The greatest yearly deterioration rate among the six panels was 8.67%, and the lowest degradation rate was 0.77%. The maximum and minimum percentage degradation rates over five years were 43.35% and 3.86%, respectively. We assessed the extent of performance decline by comparing the obtained data with the manufacturer's specifications. This work emphasizes the correlation between visual anomalies and electrical degradation, shedding light on the interplay of these factors.