Shashi wanted to know about the water which gets expelled from the AC vent, while the AC is running. The work of an AC is to lower the temperature of the room, so the process is simple, when the temperature drops, the humidity, of the air is cooled and water is expelled, just like after boiled water is cooled, it leaves off water droplets in the lid, AC, after cooling the room, expels the hot air in the form of water.