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NCT 60

OPERATIONAL & CONTROL STRATEGIES

11. Waterside Free Cooling (Water-Side Economizer)

•          Opportunity: When ambient wet-bulb is low enough, use the cooling tower directly to produce chilled water, bypassing the chiller.

•          Savings: Chiller energy drops to near-zero during suitable conditions. One of the largest ECOs in temperate climates.

12. Wet-Bulb Reset of Leaving Water Temperature

•          Opportunity: Automatically reset the tower’s setpoint (cold water temp) based on ambient wet-bulb, not a fixed value.

•          Mechanism: As WBT drops, allow tower to produce colder water. This lowers the chiller’s condenser temperature, improving chiller COP significantly (each 1°F drop in condenser water can improve chiller efficiency by 1-2%).

•          Savings: Primarily in chiller energy, with a slight increase in fan energy.

13. Optimal Approach Control

•          Opportunity: Dynamically balance fan energy against chiller energy. Find the point where fan energy increase = chiller energy savings.

•          Action: Use integrated control algorithms that vary tower fan speed to maintain the most cost-effective approach, not the smallest approach.

14. Reduce Parasitic Loads & Heat Gain

•          Opportunity: Insulate hot water lines to the tower and cold water lines in hot environments. Ensure sump is shaded/insulated to avoid solar heat gain.

V. MAINTENANCE & RETROFITS

15. Upgrade Fill Media

•          Opportunity: Replace old splash fill with modern, high-efficiency film fill (if water quality permits).

•          Savings: Improves heat transfer, allowing either reduced fan/pump energy for same duty or increased capacity in same footprint. 16. Ensure Airflow Integrity