Evaluation of room air distribution systems using computational fluid dynamics

Computational fluid dynamics (CFD) is used to predict the indoor environment of a mechanically ventilated room and overall ventilation effectiveness of air distribution systems. The prediction of indoor thermal comfort is based on Fangerʹs comfort equations incorporated into the CFD model. A radiation heat exchange model is included for the calculation of mean radiant temperature as well as heat transfer through room boundaries. The overall ventilation effectiveness is related to the energy required for achieving indoor thermal comfort and good air quality. These indices were used to evaluate room air distribution systems for heating and cooling operations. It has been found that the most effective air distribution system for heating operation differs from that for cooling. It is shown that an air distribution system that results in upward displacement ventilation performs better than others in terms of indoor air quality and energy use but may cause local thermal discomfort.