Performance Comparison of Monocrystalline BIPV Curtain Wall and Double-Skin Facade Applications for Optimized Electricity Generation and Thermal Comfort in Hot Arid Climates

Global warming and energy scarcity are growing international crises, specifically in developing countries. These problems require sustainable and advanced solutions. Building Integrated Photovoltaics (BIPV) is a solution for generating renewable energy without occupying additional space. BIPV serves dual functions: it operates as the building envelope in the form of building materials and, additionally, as a renewable energy-generating system. The technology used in the BIPV system affects indoor environmental quality (IEQ), particularly daylight, and may additionally influence indoor air temperature. The BIPV's overall operation and efficiency depend on three distinct categories of numerous factors, which can be divided into Environmental, System/Technological, and Architectural/Operational, including solar radiation, panel orientation, outdoor temperature, shading, dust accumulation, the technology used in the photovoltaic cells, and fixation techniques. In accordance with Egypt's sustainable development goals and climate change mitigation, BIPV systems generate renewable energy, consequently reducing greenhouse gas emissions. The preliminary aim of this research is to identify the optimal BIPV retrofitting application for weather conditions in Egypt that generates more electricity while increasing thermal comfort. By applying a simulation-based analysis, a quantitative comparative framework was developed. This study utilized monocrystalline (Canadian Solar CS7L-610MS) BIPV technology and simulation software, such as DesignBuilder 6.1 and PVsyst, to evaluate and compare the performance of curtain wall versus a 30° tilted double-skin facade application in an educational building in Smart Village, Giza, Egypt. The simulation framework was validated against the building's actual electricity bills (2055 MWh), demonstrating high reliability with a 1.2% deviation. The study reveals that the double-skin facade significantly outperforms the vertical curtain wall in electricity generation, especially in summer, achieving an annual yield of 245,525 kWh/year for the double-skin facade versus 144,014 kWh/year generated by the curtain wall application. Using a double-wall application successfully achieved an 11% reduction in grid energy dependency. However, the results identify a critical thermal trade-off: despite the double-skin facade having the lowest thermal transmittance (U-value of 1.945 W/m²K), annual energy consumption increases by 7% (from 2080 MWh to 2200 MWh). An integrated cavity ventilation system is a technical necessity to mitigate the associated thermal-trap effect.