The evaporator essentially works the same way as a condenser, except in reverse. The idea is that once the pressurized refrigerant has been condensed into a liquid, then depressurized and cooled by the expansion valve, it enters the evaporator, which due to its construction allows the temperature of the coils inside to drop considerably. Usually, then a fan blows air over the evaporator. The oncoming air is cooled by the evaporator, then sent out the vents of the dashboard, and right onto your face.