What is an Air cooled Chiller?

What is an Air cooled Chiller?
 
The function of an air cooled chilling unit may seem obvious since it is designed to cool its contents. Though the air cooled chilling process may seem simple, there is a great deal of engineering know-how that goes into producing the low temperatures of an air cooled chiller. The basic theory of the air cooled chiller relies on the transfer of heat or its removal from warm fluids such as water. 
 
The heat transfer process starts from an evaporator that has refrigerant in the tubes bundled around it. As fluid flows through the tubes, heat is absorbed from the contents of the tubes to form a Superheated Vapor. A compressor unit pulls the chilled vapors from the evaporator and sends it to the condenser that increases the temperature and pressure. In the tubes of the condenser, the refrigerant becomes a Sub Cooled Liquid, meaning that the heat has been rejected. 
 

The pressurized liquid moves through an expansion device and back to the evaporator where the pressure and temperature are reduced. The cycle is completed when the refrigerant flows back over the cooled water coils where more heat is absorbed.