When to Choose Closed Circuit cooling Tower?
Choosing a closed circuit cooling tower (often synonymous with a “fluid cooler” or “coil cooling tower”) is a strategic decision based on specific operational, maintenance, and environmental needs.
Primary Decision Factors: When a Closed Circuit Tower is the Best Choice
You should strongly consider a closed circuit cooling tower in the following scenarios:
1. To Protect Critical and Expensive Equipment
This is the most common reason. If the fluid being cooled is circulating through expensive or sensitive equipment (e.g., laser cutters, induction furnaces, medical imaging machines, CNC machines, large industrial process controllers), a closed circuit tower is essential.
- Why: It prevents fouling, scaling, and corrosion inside the equipment’s internal passages, which can lead to catastrophic failure, costly downtime, and expensive repairs.
When the Process Fluid Must Be Kept Clean and Contaminant-Free
If the process fluid itself must be kept pure, a closed loop is mandatory.
- Examples:
- Pharmaceutical Manufacturing: Prevents microbial or particulate contamination.
- Food & Beverage Production: Maintains hygienic standards (e.g., cooling water for pasteurization).
- Chemical Processes: Where fluid chemistry must be precisely controlled without contamination from minerals or airborne gases.
- High-Purity Water Systems: Used in semiconductor manufacturing or power plant steam loops.
3. For Freeze Protection in Cold Climates
Closed circuit towers are ideal for applications that operate in sub-freezing temperatures.
- Why: The process loop can be filled with a water-glycol mixture (antifreeze) that would be prohibitively expensive and environmentally problematic to use in an open tower where it would be lost to evaporation and drift. The glycol stays contained within the closed loop.
4. To Reduce Water and Chemical Treatment Costs (OPEX)
While the initial cost is higher (CAPEX), the operational savings can be significant.
- Water Savings: You only lose the spray water to evaporation, not the more expensive process fluid. If the process fluid is treated or expensive, this is a major saving.
- Chemical Savings: You only need to treat the spray water in the basin, which is a smaller volume and typically uses standard water. You do not need to treat the entire volume of the expensive process fluid, saving significantly on chemicals.
5. When Water Quality is Poor
If your make-up water source is hard (high mineral content) or has high suspended solids, an open tower would require constant blowdown and chemical treatment to prevent severe scaling.
- Why: In a closed circuit tower, this poor-quality water is only used on the outside of the coil for evaporation. Scaling on the coil’s exterior is easier to manage and clean than scaling inside the entire process piping system and your valuable equipment.