Dry Cooling Towers vs. Wet Cooling Towers: Key Differences
Cooling towers are essential for rejecting waste heat in industrial and HVAC systems. The two main types—dry (air-cooled) and wet (evaporative) cooling towers—differ in operation, efficiency, and applications. Below is a detailed comparison.
1. Basic Working Principle
Parameter
Dry Cooling Tower
Wet Cooling Tower
Heat Rejection Method
Uses air cooling only (no water evaporation).
Uses evaporative cooling (water + air).
Water Consumption
Zero water loss (closed-loop system).
High water loss (evaporation, drift, blowdown).
Cooling Medium
Ambient air (fans blow air over finned tubes).
Water spray + air (evaporation cools water).
Efficiency Driver
Depends on dry bulb temperature (DBT).
Depends on wet bulb temperature (WBT).
2. Efficiency & Performance
Parameter
Dry Cooling Tower
Wet Cooling Tower
Cooling Efficiency
Lower (limited by DBT).
Higher (WBT is lower than DBT).
Approach Temperature*
15–20°C above DBT (less efficient).
3–7°C above WBT (more efficient).
Energy Consumption
Higher (larger fans needed).
Lower (evaporation aids cooling).
Climate Suitability
Best in cold/dry climates.
Best in hot/humid climates.
*Approach Temp = Difference between cooled water and ambient (DBT/WBT).
