Thermo-electric performance and seasonal adaptability of BIPV facades across five Chinese climatic regions

Building Integrated Photovoltaics (BIPV) challenges in performance prediction due to complex thermal-electrical coupling. This study proposes a “Mass flow-Electric-Thermal” coupled model. This model combines optimized electrical equations, three-dimensional thermal models, and the interaction mechanism between mass flow and temperature field, enabling high-precision (root mean square error <2.87 °C/0.004 kW) simultaneous prediction of thermo-electric performance. Comparative analysis across five climate regions reveals that closed BIPV exhibits superior insulation in heating season. It reduces heat loss by 39.64%∼51.13% compared to conventional wall and demonstrates significant thermal lag effects (up to 4 h) in cold regions. Conversely, in cooling season, ventilated BIPV reduces the thermal transfer coefficient by 7.42%∼15.10% compared to closed BIPV and possesses superior temperature wave attenuation capabilities, with decrement factors ranging from 0.116 to 0.184. Although cavity depth affects power generation by less than 5%, it drives net energy savings to exceed 25.01%. Furthermore, orthogonal optimization identified cavity depth as the primary factor for shading gain, while PV coverage and efficiency determine power and energy efficiency. The optimized design enhanced annual energy-saving efficiency by approximately 20%. This study provides a theoretical foundation and data support for the configuration selection and refined design of BIPV across different climatic regions.