The temperature difference between room air and refrigerant temperatures is normally about 35°F. In passing through the cold evaporator, air is not only cooled, but some moisture in the air condenses on the evaporator. This reduces both the absolute humidity and the relative humidity of the air. The amount of moisture removed by a room air conditioner varies, depending on a number of conditions. It may be as much as three pints of water per hour for a 1-ton unit. This water drips from the evaporator into a pan. It must be disposed of to a drain or to the outside. Frequently it is not convenient to pipe the condensate to a drain. Most room air conditioners are provided with “slingers,” “scoops,” or some other means of “throwing” the condensate on the condenser. There it is vaporized and carried outside by the air circulated through the condenser.
Refrigeration Service Engineers Society, The HVAC/R Training Authority