Nissan Repair: Leakage, evaporator coils, 7 wonders

Question
Hi,
The internal working of an automobile ranks with the 7 wonders of the world to me. I have no idea what is going on except for the part I can drive my car. Recently I noticed there is a leakage coming from underneath my car. It looks like water with no smell. Is there anything wrong with the air-conditioning in my car? Thanks alot!
Kim

Answer
Kim,

An automobile airconditioner is nothing more than a heat exchanger.  The condenser is in front of the radiator and the evaporator is under the dash.  Refrigerant is compressed through the condenser and changes state to a liquid.  Then, it runs through the system into the evaporator and changes state into a gas.  When the refrigerant turns into a gas it gets cold and a fan is used to blow air through the evaporator coils.  The result is cold air.  Now, this cold evaporator attracts the mositure out of the air and eventually enough moisture collects where it runs off into the bottom of the case where it drains out a tube onto the ground.  It is kind of like a cold drink that gets moisture on the outside of the glass.  Anyway, that is what you are observing under the car.