Numerical study of two-axis adaptive HVAC vents in developing uniform thermal comfort and improving energy savings

Human thermal comfort in buildings is an increasingly important topic. Improvements to system efficiency will bring about considerable benefits to power consumption and thermal comfort of building occupants. This work examines the use of an adaptive vent system (AVS) within a university classroom. The system will use directional cooling to lower the temperatures of occupied regions, reducing cool air supply to unoccupied regions and thus waste. Computational fluid dynamics simulations were conducted to characterize the behavior of the AVS and compare it against a standard diffuser system. The simulations show that directed cooling from the adaptive vents reduces the temperature and relative humidity surrounding the occupants approximately 3.3 times faster than the standard system. However, the draft rate has also increased significantly. Despite this, the simulations indicate that the AVS is capable of greatly increasing the cooling efficiency of the overall system, especially if the supply airflow rate were to be lowered.