Cooling towers are the heart of any district cooling plant. Cooling towers utilize cool dry air to absorb heat from the warm water entering the tower through evaporation process which brings the water temperature down to the wet bulb air temperature. the latter is lower than the air-dry bulb temperature. That's why the water could reach lower temperatures than the air used to cool it.

the cool water is then sent back to the chillers to absorb heat from the refrigerant and the cycle repeats.