Computational study of natural ventilation air flow and heat transfer for a room of different flow path and window configurations in Bangladesh

Abstract

Natural ventilation is an effective system to reduce the consumption of energy required to condition buildings and to improve the quality of indoor air. Buildings will construct such a way that can use natural energy more proficiently can lead to save energy, while maintaining comfort for occupants’. This study has been focused to airflow and heat transfer analyses in a room through opening(s)/awning opening(s) and then compare the results obtained from both different opening. Computational fluid dynamics (CFD) whose application is gaining popularity has been used to model single-sided and cross ventilation in a single room through window where door was closed. Two and Three-dimensional model has been calculated of a cubic room assuming twelve different opening configurations. In this research, Reynolds averaged Navier–Stokes equation (RANS) approach has been applied to wind driven natural ventilation in a cubic building. Two equation based k-ϵ model is used for stationary and unsteady solution. Moreover, turbulent air flow coupling with or without heat also has been considered and showed in different results. The mathematical model has been solved numerically with CFD/commercial software. The temperature fields, flow patterns, ventilation rate, heat transfer coefficients and temperature distribution effectiveness have been presented and discussed. The numerical results have been also compared with experimental data, showing a good agreement. The room heated up and reached its thermal comfort level, but the velocities exceeded the maximum acceptable level set by ASHRAE [15] guidelines. In the case of heat transfer and ventilation, Awning opening gives better result than opening.