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Comparison: Dry Cooling Tower vs. Wet Cooling Tower

FeatureDry Cooling TowerWet Cooling Tower (Evaporative)
PrincipleSensible Heat Transfer (Air cools fluid)Latent Heat Transfer (Evaporation cools fluid)
Water UsageZero (except for occasional cleaning)High (continuous evaporation and blowdown)
Coolant CircuitClosed LoopOpen or Closed Loop
Cooling EfficiencyLower. Highly dependent on ambient dry-bulb temperature.Higher. More efficient as it depends on ambient wet-bulb temperature, which is lower.
Footprint & SizeLarger for the same cooling capacity.Smaller for the same cooling capacity.
Capital CostGenerally HigherGenerally Lower
Operational CostLower (no water/chemical costs, but higher fan power).Higher (continuous cost of water, water treatment chemicals, and pumping).
Environmental ImpactNo water consumption; no vapor plume.High water consumption; produces a visible vapor plume.
MaintenanceCleaning fins to prevent clogging.Combating scale, algae, and corrosion; water treatment.
Risk in Cold WeatherRisk of coolant freezing.Lower freezing risk due to constant movement.