An experimental investigation on the relationship between shading, dust accumulation, and the performance of building-integrated photovoltaic modules

Photovoltaic (PV) systems are increasingly deployed in urban and remote areas, but their performance is significantly affected by partial shading and dust accumulation. Understanding these effects is crucial for optimizing the design and maintenance strategies of PV systems. In Beijing, a 13.2 kW grid-connected experimental platform was built to monitor the temperature, power generation, and solar radiation intensity of PV modules in real-time. Through this platform, the effect of different shading methods on module performance under variable proportional shading and specific proportional shading was studied. To address the critical gap in region-specific dust impact studies, three representative soil types—laterite (iron-rich, simulating southern China's humid climate), loess (coarse-grained, typical of northwestern arid regions), and kaolin (dense clay, mimicking mineral-rich areas)—were systematically tested to simulate natural dust accumulation across diverse environments. Based on the experimental data, an optimal fitting model for the relationship between relative power generation efficiency and dust density was established. Key findings reveal that kaolin, due to its high-density particle composition, causes the most severe power loss (42.15% at 25 g/m2), followed by laterite (44.42%) and loess (37.98%), demonstrating how regional dust properties dictate PV performance degradation. Additionally, the effect of dust deposition in the powder form and after solidification by water spraying on the characteristics of PV arrays was explored. The results show that under 20% shading, different shading methods have varying effects on PV modules. Concentrated shading results in greater power loss compared to dispersed shading. In practical installations, horizontally arranged PV modules reduce power loss more effectively than vertically arranged ones due to less impact from shading. Three types of dust accumulation have minimal impact on open-circuit voltage (Voc) but significantly reduce short-circuit current (Isc), leading to a corresponding decrease in output power as dust density increases. The Isc and output power are most noticeably reduced when dust deposition occurs after solidification by water spraying. The quadratic polynomial model best describes the relationship between power generation efficiency and dust density, providing a tool for predicting region-specific PV performance losses caused by laterite, loess, or kaolin accumulation.