Abstract
This research identifies solar photovoltaic (PV) energy losses under humid tropical conditions using a Performance Ratio Cascade Loss Model (PRCLM) at the 100 kW rooftop installation of the Kelappaji College of Agricultural Engineering and Food Technology (KCAEFT), Kerala Agricultural University. Field observations collected in November 2024, combined with inverter-based generation data for 2025, were used to estimate thermal, irradiance, soiling, orientation, and system losses in accordance with IEC 61724-1:2021. Results show that thermal losses (9–10%) constitute the dominant controllable loss component, while soiling losses increased from 3% to 6% over the post-monsoon period without cleaning intervention. The PRCLM showed strong agreement with the observed performance ratios, yielding a root-mean-square error (RMSE) of 0.003. A cost-effective lux-to-irradiance conversion protocol was validated as a replicable frugal monitoring methodology for resource-constrained agricultural campus installations. The cascade-based decomposition framework, which combines frugal monitoring inputs with IEC 61724-1:2021 standardization, represents the methodological novelty of this study. Targeted interventions, including scheduled bi-annual panel cleaning, rear-ventilation enhancement, and orientation correction, are recommended to restore measurable energy yield. Results should be interpreted within the limitations of the dataset and modeling assumptions.