A water cooled chilled water system works by using water to transfer heat from a building to an external cooling tower, where the heat is then dispersed into the atmosphere. The process involves:

1. 
   
2. 1. Cool water is pumped from the cooling tower to the chiller unit, where it is used to cool a refrigerant.
3. 2. The cooled refrigerant is then pumped through a series of heat exchangers, where it removes heat from the building's water supply.
4. 3. The warmed water from the building is then returned to the chiller unit, where the heat is transferred back to the refrigerant.
5. 4. The warm refrigerant is then pumped back to the cooling tower, where the heat is expelled into the atmosphere and the refrigerant is cooled again.
6. 5. The cooled water is then returned to the chiller unit to start the process again.