A chilled water HVAC system is a type of air conditioning system that uses a central chiller to cool water, which is then circulated through a network of pipes to air handlers throughout the building. The air handlers contain cooling coils that absorb heat from the air, transferring it to the chilled water. The cooled air is then circulated throughout the building, providing a comfortable environment for occupants. Chilled water systems are often used in large commercial buildings, as they are more efficient than traditional air conditioning systems.