Enhancing sustainable urban development by combined application of bifacial PV and a high-reflectance roof coating: a case study

Mitigating climate change has become increasingly critical in the context of accelerating urbanization and rising energy demand. The long-term goal of effective and sustainable urban energy planning is to develop practical strategies that ensure access to affordable energy while enhancing thermal comfort and urban livability. This paper presents a technical evaluation of the energy performance of a bifacial PV system installed on the roof of a warehouse located in a suburban area (near Lodz airport). The efficiency of the system is assessed in comparison to traditional PV panels. To investigate the potential gains from reflected solar radiation, a high-reflectance exterior roof coating was applied to half of the monitored roof surface, allowing for direct performance comparison between coated and uncoated surfaces. The applied reflective membrane, a flexible and UV-resistant coating, also serves to reduce roof surface temperatures and enhance PV efficiency. The influence of the reflective surface on energy yield was assessed with the historical records: the documented yield of the examined scenario is almost 10%. Rather than relying on numerical modeling, this work presents a real-world case study that demonstrates a good practice example for urban sustainability.