Cfd Simulations Of Thermal Comfort For Naturally Ventilated School Buildings

A comfortable learning and teaching environment is one of the key concerns in the design of school buildings. In Singapore public school buildings, most of classrooms are naturally ventilated, for the sake of energy saving and sustainable design. It is necessary to study the impact of environmental conditions and design features to get some clues to facilitate the designers for naturally ventilated school designs. In this study, CFD simulations have been carried out to evaluate the natural ventilation condition of the classrooms and identify the plausible reasons causing thermal discomfort for an actual school in Singapore. The CFD approach adopted in this study is closely in reference to the CFD methodology outlined in Green Mark 2015 for Non Residential Building from Building and Construction Authority (BCA), subject to the four prevailing wind conditions available in Singapore. Meanwhile, some mitigation measures including the removal of incline roofs have been explored in order to enhance the natural ventilation for those classrooms. In addition, thermal comfort analyses have been performed with simulations including ceiling fans and heat loads. CFD simulations demonstrate that classrooms at higher levels experience weaker cross ventilation than those at lower levels for the three prevailing wind conditions from the north, northeast and south, respectively. This may due mainly to the fact that the school resides within the wake zone of the surrounding buildings. The flow directions across the classrooms of concern are found to be opposite to the prevailing wind direction under the three prevailing wind conditions. Thermally uncomfortable conditions in the classrooms at higher levels are well simulated and captured using the proposed thermal comfort analyses. All the observations match well with the feedback from the school. Besides, scenario-based studies with regard to plausible mitigation measures have shed the lights towards enhanced natural ventilation across the classrooms of the school of concern.