Towards the new generation of courtyard buildings as a healthy living concept for post-pandemic era.

COVID-19 has laid a context for holistic research and practical approaches towards health issues in buildings. This study focuses on one particular residential building type, which is a combination of a modern apartment building with private double-oriented terraces, and a traditional courtyard building. This principle improves several aspects of healthy buildings and contributes to address indoor-outdoor interactions, daylighting, and the use of natural ventilation. The purpose of this study is to determine the factors underlying a particular type of semi-outdoor space within building forms and to explain their microclimatic behavior in buildings. One solid model and twelve porous apartment buildings with different numbers of porous sides, and terrace widths are evaluated using computational fluid dynamics. The k-ε turbulence model is adapted to simulate airflow in and around a four-story building. CFD simulations were validated against the wind-tunnel measurements. Investigations indicated that increasing the number of porous sides reduces the internal mean and maximum ages of air by -15.75 and -36.84%, which means improved ventilation performance. However, it leaves a negative trace on ventilation of the semi-outdoor spaces. Meanwhile, increasing the width of the terraces enhances the ventilation performance by reducing the mean age of air in units, courtyards, and terraces by -20%, -20%, and -9%, respectively.