Dynamic evaluation of the effect of cavity depth in a double-skin façade with hybrid panels on seasonal energy performance

This study presents a comprehensive numerical analysis to investigate the impact of the air cavity depth in a Double-Skin Façade (DSF) integrated with Hybrid Photovoltaic/Thermal (PV/T) panels on the seasonal energy optimization of office buildings in Tehran's climate. The primary objective was to determine the optimal cavity depth to achieve minimal energy consumption and maximal utilization of solar energy throughout the year. For this purpose, a dynamic model of the system was developed using TRNSYS and MATLAB software, with real-world climatic data from Tehran employed as input boundary conditions. Within a parametric analysis framework, 22 different configurations with cavity depths ranging from 5 to 100 cm were evaluated. Key performance indicators, including heating and cooling loads, electrical energy balance (net production and consumption), and the reduction rate of carbon dioxide emissions, were calculated for each configuration. The simulation results demonstrated that varying the cavity depth has a significant impact on the system's thermodynamic behavior, including airflow patterns, heat transfer rates, and the overall efficiency of the solar system. Based on the results, the optimal cavity depth for Tehran's climatic conditions was determined to be 20 cm for warm seasons and 30 cm for cold seasons. Furthermore, increasing the depth to approximately 80 cm maximized electricity generation and reduced primary energy consumption by about 95% compared to the base case.