Numerical assessment of the efficiency of fenestration system and natural ventilation mechanisms in a courtyard house in hot climate

摘要

This paper presents an assessment of the efficiency of the fenestration system in a courtyard house in hot climate. The empirical work draws better understanding of the wind behavior inside and outside the building and the manner of both the wind-driven and stack ventilation through conducting computational fluid dynamics (CFD) modeling. Numerous steady state simulations were applied for different time-steps to cover possible variations of boundary conditions to get aggregated results for airflow during summer in a couple of spaces in the house. The results were analyzed and values of the air change rates were extracted for the summer season. The role of each component involved in the natural ventilation process was identified through determination of the airflow pattern and break-down assessment. Simulations showed the stabilization of wind velocity inside the courtyard which protects the building against undesirable high velocities. The analysis demonstrated the efficiency of the distribution of openings as well as the role of the roof wind-escape in the enhancement of air circulation and the indoor air quality. For two different spaces, the wind escape device is found to increase the air change rates (ACH) as more as 25% and 60% than the 2-side ventilation case in which the ACH was increased as more as 45% and 27% than the single-side. The relationship between cross ventilation and indoor temperature was illustrated through the transient simulations.