Connection between Air Diffusion Performance Index (ADPI) and Ventilation Effectiveness (EV): Effects of Diffuser Adjustment and Return Air Placement

This presentation provides fundamental design data that supports optimal diffuser selection in mixing ventilation with heating and cooling operation. It shows how diffuser adjustment, room-supply air temperature differences and return air grille location impact ADPI and E_V. The study points out connections between ADPI and E_V and shows similarities and differences for heating and cooling operation. It presents the operation characteristic that provide good E_V while maintaining acceptable ADPI. Also, it shows how diffuser adjustment may improve E_V. Furthermore, the presentation shows the cases where return air location may have a significant effect on ADPI and E_V.