Advantages and Challenges of Using a Coil
Advantages (Why it’s used):
- Zero Water Loss: The closed-loop system is its biggest advantage in water-scarce regions.
- Clean Process Fluid: No contamination from outside air or water treatment chemicals.
- Low Maintenance: No problems with scaling, algae, or Legionella bacteria inside the coil.
- Environmental Compliance: No visible vapor plume (in most conditions) and no chemical drift.
Challenges (Limitations of the Coil):
- Lower Efficiency: Heat transfer through a metal wall is less efficient than direct evaporative cooling. The coil’s performance is limited by the ambient dry-bulb temperature.
- Larger Size and Cost: To achieve the same cooling as a wet tower, a much larger (and more expensive) coil surface area is required.
- Weather Sensitivity: On very hot days, the cooling capacity drops significantly because the temperature difference between the hot fluid and the warm air is smaller. The coil cannot cool the fluid below the ambient air temperature.