A cooling tower is a device that removes waste heat from a coolant stream, usually water, by cooling it to a lower temperature and releasing the heat into the atmosphere. The key process is evaporative cooling, where a small amount of water evaporates as it comes into contact with air, cooling the remaining water. This cooled water is then recirculated back to industrial processes or air conditioning systems to absorb more heat. Cooling towers are commonly used in power plants, chemical plants, HVAC systems for buildings, and other industrial applications where large amounts of heat need to be dissipated. They can vary greatly in size—from small units on rooftops to massive hyperboloid structures seen at power plants. There are two main types:
- Natural draft cooling towers rely on natural air movement.
- Induced draft cooling towers use fans to pull air through the tower.
Water heated by industrial processes or air-conditioning condensers is pumped into the cooling tower, sprayed over fill material to maximize air-water contact, and cooled by evaporation before returning for reuse. This cycle helps maintain efficient cooling for large-scale equipment or building systems. In brief, a cooling tower is a specialized heat exchanger that uses air and water contact, mainly through evaporation, to reduce water temperature and expel heat to the atmosphere for use in many industrial and building cooling applications.
