Integrating bioclimatic features in building energy modelling to study thermal performance of a naturally ventilated hostel building in the composite climate zone of India

Buildings account for 37% of energy demand globally, and cooling consumes more energy and contributes more emissions in hot climates. This study evaluates the thermal performance of a non-air-conditioned hostel room at Shiv Nadar Institution of Eminence, Delhi NCR, India, through an integrated approach combining 3D energy modelling (Google SketchUp), transient thermal simulations (TRNSYS 18), and simulating the dynamic movement of air, in and out of a building using TRNFLOW (Transient Network Flow). A calibrated model was developed using real-time sensor data and validated against two weather datasets to assess comfort hours (indoor temperatures: 18°C–27°C). Bioclimatic potential analysis guided passive cooling strategies, including optimized natural ventilation, enhanced thermal mass, and improved glazing. Heat flux analysis revealed that outward-facing insulation reduced peak heat gain by 27%. At the same time, double-glazed units minimized convective losses (decrement factor: 0.4). TRNFLOW simulations further refined airflow dynamics by incorporating wind pressure and temperature gradients, extending summer comfort hours by 18–28% though winter ventilation trade-offs were noted. The findings demonstrate that sequential heat flux-airflow analysis is critical. The study advances sustainable building practices by quantifying the efficacy of passive interventions and proposing a simulation-integrated design process for high-occupancy buildings.