How to Calculate Cooling Tower
What is Cooling Tower?
Cooling tower sizing removes waste heat to atmosphere. It's determined by cooling load and approach temperature to wet-bulb.
Formula
Approach = outlet temp - wet-bulb temp (typically 2-4°C)
- C
- C value — Variable used in the calculation
Step-by-Step Guide
- 1Calculate: Q = m×cp×ΔT where ΔT is cooling temperature drop
- 2Approach = outlet temp - wet-bulb temp (typically 2-4°C)
- 3Size tower for required cooling capacity
Worked Examples
Input
Q = 500 kW, water flow 60 kg/s, approach 3°C, wet-bulb 25°C
Result
Tower outlet ≈ 28°C, inlet 36°C
6°C drop required
Common Mistakes to Avoid
- ✕Confusing dry-bulb with wet-bulb temperature
- ✕Over-sizing tower (reduces efficiency)
Frequently Asked Questions
How does wet-bulb affect cooling tower size?
Higher wet-bulb (humid climates) reduces cooling effectiveness; larger tower needed for same duty.
What's approach temperature?
Minimum difference between cooled water and wet-bulb; smaller approach requires larger (costlier) tower.
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