Development of The Passive Air Mixing Chamber for an Air Handling Unit

Air mixing chamber in an air handling unit (AHU) is an important part to affect heat exchange efficiency and the controllability of AHU. In this study, the novel definition of air mixing ratio (AMR) is proposed, and several ideas to improve AMR has been investigated by computational fluid dynamics (CFD) simulation and experiment. In conventional air mixing chamber, airflow characteristics show that outdoor air flowing into the air mixing chamber is suppressed by a large volume of return air, and OA and RA are not mixed well. AMR of the conventional air chamber is quite low as 20
_~
50%. Among the cases investigated in this study, the case “Double inducing chamber / three slits on each side walls” shows the best mixing state. AMR of this case shows about 80%, and pressure loss around 20 Pa. These performance results have been validated through a separate experiments.