Numerical investigations into the performance of doorway vertical air curtains in air-conditioned spaces

The influence of wind velocity, jet width, jet angle and heat input on the efficiency of doorway air curtains in small air-conditioned spaces was investigated usical numerical simulation. Results show that proper design and installation of air curtain reduce air exchange between indoor and outdoor up to 90%. Optimum performance is obtained when the curtain air just reaches the floor. The corresponding critical air curtain velocity increases with external wind velocity normal to the doorway and with temperature difference between indoors and outdoors. Increase of the air jet velocity above this critical value leads to a reduction in the air curtain efficiency.