Impact of vertical shading designs on the cross-ventilation performance of a high-rise office building

Historically, windows shading systems have been part of sustainable design elements that minimize solar heat gain while still allowing fresh air to pass through. However, there is a lack of comprehensive research on the impact of shading systems on natural ventilation in furnished indoor spaces. This study aimed to assess the efficacy of vertical shadings on the cross-ventilation performance in an office building through numerical analysis by utilizing computational fluid dynamics. Site measurements were conducted to compare with the numerical results and were used as boundary conditions for the numerical simulations. The results showed that incorporating vertical shadings with the window has the potential to enhance the ventilation rate when the wind direction ranges from 45 degrees to 90 degrees. Then, different vertical fin settings were applied for various specific window types for further analysis. The initial case (awning window) with central shading resulted in a 30.46 % increase in the airflow rate compared to that in the non-shading scenario. The implementation of vertical shadings for sash windows can be considered to be the most effective combination, which resulted in a 12.04 % increase in the ventilation rate, a reduction of 17.73 % in the velocity non-uniformity coefficient, and a decrease of 31.47 % in the percentage area of the dead zone. Lastly, a first attempt to demonstrate the potential of altering the furniture placement to improve the natural ventilation with window shading systems is presented. The ventilation rates were slightly affected by the placement of furniture, while the local age-of-air surrounding the occupant could be reduced by 56.21 %. This study provides a practical architectural strategy for enhancing indoor natural ventilation behavior through the implementation of window vertical shadings.