The cold air that comes from your car's air conditioner comes from this core. A chemical is pumped through the evaporator core (which is much like a small radiator or heater core). The evaporator carries the cold chemical into the car where an interesting exchange takes place ... the chemical exchanges cold air for hot air! It literally saps the hot air out of the car by absorption. The cold air that is radiated from the evaporator is then blown into the car's ventilation system, cooling you down. Dehumidification also takes place during air conditioning. Ever wonder where all that water comes from that drips under your car? Now you know!