What Is The Working Principle of Cooling Tower

A cooling tower works on the principle of heat rejection through evaporative cooling. Its main function is to remove unwanted heat from water used in industrial processes, HVAC systems, or power plants and release it into the atmosphere.

So What Is The Working Principle of Cooling Tower? Here’s the working principle step by step:

1. Hot Water Enters the Cooling Tower

Warm water from a condenser, chiller, or industrial process is pumped to the top of the cooling tower.

This hot water is distributed evenly over the fill media using spray nozzles.

2. Heat Transfer by Evaporation

As the water flows down the fill, it spreads into thin films or droplets, increasing the surface area.

At the same time, air is drawn or forced through the tower (depending on whether it’s induced draft, forced draft, or natural draft).

A small portion of the water (typically 1–2%) evaporates.

The evaporation process absorbs heat from the remaining water, cooling it down.

3. Air-Water Contact

Warm, moisture-laden air rises and exits through the tower outlet.

The cooled water collects at the bottom in the cold-water basin.

4. Recirculation

The cooled water is pumped back to the equipment (chillers, condensers, or industrial process) to absorb more heat.

The cycle repeats.

Key Points

Driving force: Evaporation and sensible heat transfer between water and air.

Efficiency depends on:

Wet bulb temperature of ambient air (limit of cooling).

Fill design (contact surface area).

Airflow (fan or natural draft).

Water distribution system.

In short: Cooling towers reject heat from water by evaporating a small part of it, using air circulation to carry away the heat, and recirculating the cooled water back to the system.