Recommendations for Winterizing Cooling Towers




During the warmer months, cooling towers are a necessity for the function of your business. However, as winter approaches, there’s less of a need to keep your cooling systems on because of the low outside temperatures. Winterizing your cooling towers is the process of preparing your cooling towers to be shut down during these colder months. In this blog, we’ll discuss our recommendations for winterizing cooling towers, as well as:

  • How to winterize cooling towers

  • Recommended winterization techniques

  • Induced draft cooling tower procedures

  • Natural draft cooling tower procedures

How to Winterize Water Cooling Towers

Once temperatures begin to drop, it’s time to begin preparing for the proper shutdown of your cooling systems. Of course, we recommend general maintenance throughout the year to ensure your cooling towers are running smoothly, but it’s especially important to prioritize winterization tasks to avoid costly problems in the future. Delaying or ignoring these critical actions can cause issues such as:

  • Unsafe working conditions

  • Broken equipment

  • Higher energy costs

  • Code violations

Recommended Winterization Techniques for Cooling Towers

It goes without saying that proper winter operation of any water cooling system is heavily reliant upon operator inspection and control. A high degree of attention is essential for efficient performance during cooler months. If your ambient dry bulb temperatures reach 45° F, normal operating procedures should be suspended and an appropriate winter operational plan should be implemented. Below are several winterizing recommendations for different types of water cooling towers:

Induced Draft Cooling Towers

Counterflow

When the ambient temperature ranges from 20˚ to 45˚ F, a visual inspection of the cooling system should be made every two to four hours, especially in the louver and fill areas. Cooling towers in environments where the air temperature falls below 20˚ F should be visually inspected every two hours. Cold (return) water temperature from the cooling tower should be monitored continually and not allowed to drop below 50˚ F. To guard against ice formation, take the following precautions:

  • Maintain plant heat load at the highest possible level

  • Maintain circulating water flow at the highest possible rate

  • Regulate airflow to control ice formation

Crossflow

For induced crossflow cooling towers, the recommendations are similar to those advised for induced counterflow cooling towers. However, this type of cooling tower can be equipped with one or more of the following accessories to improve winter operation:

  • Longitudinal dam (weir) in hot water basins

  • Larger orifice nozzles on outboard row(s)

  • Ice retainer bar on top inboard edge of louvers

  • Variable-speed fan motors with reversing feature

  • Hydraulic or electric-driven variable speed fans with reversing feature

  • Total hot water bypass

  • Heavy-duty fill bars and fill hangers

Natural Draft Cooling Towers

Counterflow

If the ambient dry bulb temperature falls below 45˚ F, normal operating procedures should be halted. This is especially important for natural draft cooling systems because as ambient air temperatures drop, the air velocities increase which elevates the probability of ice formation. A visual inspection of the cooling system should be made every two to four hours, especially in the louver and fill areas, when the ambient temperature reaches 20˚ to 40˚ F. Cooling towers in environments where the air temperature falls below 20˚ F should be visually inspected every two hours. Cold (return) water temperature from the cooling tower should be monitored continually and not allowed to drop below 50˚ F.

Crossflow

For natural crossflow cooling towers, the recommendations are similar to those advised for natural counterflow cooling towers. However, this type of cooling tower can be equipped with one or more of the following accessories to improve winter operation:

  • Total hot water bypass

  • De-icing ring with large capacity nozzles

  • Ice retainer bar on top inboard edge of louvers

  • Ice screens behind louvers

  • Heavy-duty fill bars and fill hangers

Find More Winterization Information from CTI

Although these recommendations are directed toward industrial cooling towers, these principles are also valid when winterizing HVAC cooling towers. For more information regarding proper winterization techniques for cooling towers, browse our selection of papers on our website or purchase our chapter on winterization.


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