Mixing of conditioned air with room air is an essential factor for uniform comfort in homes. This can be achieved by creating the correct combinations of temperature and air motion in the occupied zone. Discomfort can be caused by excessive air motion, excessive room air temperature variations, or failure to deliver or distribute air according to load requirements. Effective mixing is even more challenging in low load homes with downsized HVAC systems because the design flow rates are lower.

We used computational fluid dynamics modeling to evaluate the performance of high sidewall air supply for residential applications in heating mode, and varied the supply velocity and supply temperature. We considered two configurations, corresponding to an unfurnished and furnished room and compared the results, then evaluate thermal comfort by determining the air diffusion performance index (ADPI). The higher the ADPI value, the more comfortable the space is for most occupants. High sidewall supply inlets can achieve good mixing and provide acceptable comfort levels. Recommendations are given for the system operating conditions to increase comfort.