Inputs
Formula reference
Q = flow × ρ × cp × ΔT
E = Q × 3600 / (latent heat × 1000)
B = (E + D) / (CoC − 1)
M = E + D + B
What this calculator answers
It provides a transparent preliminary estimate for an open-recirculating cooling tower. The heat balance uses water density near 1,000 kg/m³, your selected specific heat, and the cooling-water range. The concentration balance treats drift as a water and dissolved-solids loss, so blowdown is calculated from evaporation plus drift.
Use measured inputs when possible
- Use the tower or condenser-water meter for circulating flow.
- Use actual return and supply temperatures for the range.
- Use the water-treatment target and chemistry review for CoC.
- Use the manufacturer’s certified drift rate instead of the default.
Boundaries
This is not a tower selection, pump selection, water-treatment, discharge, Legionella, cost, or permit decision. Leaks, overflow, basin volume, intermittent operation, and detailed air-side mass transfer are outside this simple balance.
Final design should use equipment data, water chemistry, local requirements, and qualified review.
FAQ
Does higher CoC always work?
No. Higher CoC reduces blowdown only while scaling, corrosion, biological control, and discharge limits remain acceptable.
Why is the result different from a percentage shortcut?
Evaporation depends on heat rejected and latent heat. A fixed percentage shortcut can be useful only when its operating assumptions are documented and applicable.