Working principle of Closed-Circuit cooling Tower
How It Works: A Two-Circuit System
The key to understanding it is that it has two completely separate circuits:
- The Closed Process Loop (Primary Circuit):
- This is the loop that needs cooling. It contains a clean fluid (e.g., heated water from a process, a chiller condenser, an industrial machine, or an engine).
- This fluid is pumped through a coil bundle (a series of pipes with fins to increase surface area) located inside the cooling tower.
- Crucially, this loop is closed. The process fluid never leaves these pipes.
- The Open Evaporative Loop (Secondary Circuit):
- This is a separate system that exists only within the cooling tower itself.
- A pump draws water from the tower’s cold water basin and sprays it evenly over the outside of the coil bundle that contains the hot process fluid.
- Simultaneously, a fan at the top of the tower draws ambient air across this wet coil bundle.
- A small portion of this spray water evaporates. The energy required for this evaporation (the latent heat of vaporization) is drawn as heat from the coil.
- This cools the coil, which in turn cools the process fluid inside it.