A holistic framework to utilize natural ventilation to optimize energy performance of residential high-rise buildings

A novel holistic framework was established using Building Information Modelling (BIM) to estimate accurately the potential of natural ventilation of residential high-rise buildings. This framework integrates Computational Fluid Dynamics (CFD) simulation, multi-zone-air-flow modelling, and Building Energy Simulation (BES) to calculate ventilation rates under the mechanisms of wind-, buoyancy- and wind and buoyancy-driven ventilation. The framework was applied to a 40-storey residential building in Hong Kong for estimating the potential of natural ventilation in residential high-rise buildings. The results show that the building can save up to 25% of the electricity consumption if the building employs wind-driven natural ventilation instead of mechanical ventilation. The electricity consumption can be further reduced up to 45% by facilitating the buoyancy-driven natural ventilation. However, natural ventilation is found to be effective only if the temperature difference between indoor and outdoor is less than 2 degrees C. The study suggests to orienting residential high-rise buildings at an oblique angle with the prevalent wind direction than positioning perpendicular to the prevalent wind direction. Furthermore, the framework recommends promoting the wind- driven natural ventilation at top floors of residential high-rise buildings and to facilitate wind and buoyancy- driven natural ventilation at middle and lower floors of the buildings.