Cooling Tower Evaporation & Makeup Water Calculator

Calculate cooling tower evaporation rate (m³/h and GPM), blowdown discharge, drift losses, Cycles of Concentration (CoC), and required raw makeup water duty.

Circulating Water Flow & Range

Circulation Rate Q_circ (m³/h): Main condenser circulating water

Cooling Range ΔT (°C): Hot water in minus cold water out

Cycles of Concentration (CoC): Typical: 4.0 to 6.0 cycles

Drift Loss (% of Circulation): High-efficiency drift eliminators

Water Balance & Consumption

Required Makeup Water:

—

Evaporation Loss E:

—

Blowdown Discharge B:

—

Makeup Flow Rate (GPM):

—

Total Heat Dissipation Duty:

—

Recommended Tools & Equipment

Tested hardware and components for high reliability

100% Free Tool Zero Sign-Up

Frequently Asked Questions

What is Cycles of Concentration (CoC)?

CoC is the ratio of dissolved solids (such as chlorides or silica) in the circulating water basin compared to the raw makeup water. Increasing CoC from 2 to 5 cuts blowdown wastewater by over 70%.

Why is blowdown necessary in cooling towers?

Pure water evaporates, leaving behind dissolved minerals. Without blowdown, mineral concentrations exceed saturation solubility, precipitating calcium carbonate and silica scale onto condenser tubes.

How does cooling range affect evaporation rate?

Evaporation removes latent heat (~2400 kJ/kg). For every 10°C of temperature drop across the tower, roughly 1.5% to 1.8% of the total circulating water volume evaporates.