Comparative Analysis of Thermal and Electrical Performance of BIPV Systems According to Building Envelope Type

This study comparatively analyzes the thermal and electrical performance characteristics of building-integrated photovoltaic (BIPV) systems according to the type of building facade.An insulated wall-type BIPV system using glass-to-backsheet modules and a curtain wall-type BIPV system using glass-to-glass modules were installed in a mockup building under identical conditions.The solar irradiance, ambient temperature, module front surface temperature, indoor-side surface temperature, and power generation were measured to analyze the thermal characteristics and power generation performance of the two systems.The operating temperature of the module depended on the facade structure.Under high-irradiance conditions, the front surface temperature of the module in the insulated wall-type BIPV system reached approximately 55 C, whereas that in the curtain wall-type system remained at approximately 50 C, indicating that the curtain wall system maintained a lower operating temperature.Correspondingly, the curtain wall-type BIPV system generally exhibited higher electrical performance, and its average efficiency was approximately 0.4-0.5 pp higher than that of the insulated wall-type system.In particular, although the rated efficiency of the curtain wall-type BIPV module was lower than that of the insulated wall-type module, the curtain wall system exhibited a higher efficiency under actual operating conditions, suggesting that differences in the module operating temperature associated with the facade configuration and rear thermal conditions may contribute to variations in the actual power generation performance.The results of this study suggest that the facade structure and rear-side thermal environment should be considered along with the rated module efficiency in the design and performance evaluation of BIPV facade systems.