A study on the effect of the airflow rate of the ceiling type air-conditioner on the ventilation performance

We performed a study on the effect of the discharge airflow rate of the ceiling type airconditioneron ventilation performance in the lecture room with the mixing ventilation. Theexperiments and CFD were conducted for analyzing ventilation performance. The concept ofmean air age and indoor CO2 concentration were used for evaluating ventilation performance.We made the CO2 generation model in the simulation and calculated a lot of cases withrespect to the airflow rate of air conditioner and the ventilation flow rate. And the selectedexperimental measurements were performed in the lecture room of the same layout as thenumerical one for verifying simulation results. Mean air age is gradually increased, but CO2concentration is oppositely decreased in the occupied zone with the increment of thedischarge airflow rate of the ceiling type air-conditioner. This result shows that both of meanair age and residual life time must be considered for evaluating ventilation performance whenthe contaminants are generated indoors. And the increment of discharge airflow of the ceilingtype air-conditioner can induce the piston effect and push the contaminants out of theoccupied zone. From this result, it is found out that that ventilation performance can beincreased when the momentum source like an air-conditioner is used in the room with themixing ventilation.