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Improve the efficiency and safety of your cooling tower

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Picture of two commercial cooling towers on top of a building
Certain cooling tower upgrades may be eligible for a rebate that will pay 50% of the project costs, up to a maximum of $5,000. Before starting your project, contact water efficiency staff to ensure that it qualifies for a rebate.
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A cooling tower is a heat removal device that uses water to transfer heat from a building or process into the atmosphere through evaporation. Cooling towers can be found in large multifamily buildings, some supermarkets, manufacturing facilities and wherever large amounts of cooling is required. Cooling towers can consume thousands of gallons of water every hour. Even small improvements in operational efficiency can save water, chemicals, and, of course, money!

Attention to maintenance and using efficient technology not only ensures efficient operation but can also reduce the risk of spreading the pathogen Legionella. When inhaled, Legionella can cause a severeform of pneumonia.  Evaporative cooling towers are an ideal breeding ground for Legionella which can then be aerosolized and inhaled by workers or the public. This is why developing and following a building management plan that includes proper treatment and maintenance of your cooling tower is essential.  Check out the CDC’s guide to controlling Legionella in your facility and cooling tower. 

Here are a few ways you can improve efficiency:  

Know your cooling tower’s cycles of concentration. Cycles of concentration refers to the number of times a cooling tower recycles water before the water needs to be discharged to the sewer system. A higher number of cycles means less water and chemicals are consumed. Our primary water source, the Bull Run Watershed, is a low-mineral water that can allow many properly maintained towers to operate at six to ten cycles. In the summer, Portland may blend Bull Run water with groundwater, which will impact the number of cycles. Sign up here if you would like to be notified when groundwater is being used so you can be sure that your cooling tower is optimized for the most efficient operation.

Install a conductivity controller to automatically control blowdown. Conductivity is a measure of water’s ability to conduct electricity. In cooling water, it indicates the amount of dissolved minerals in the water. As the name implies, a conductivity meter or controller continuously measures the conductivity and discharges water only when the conductivity set point is exceeded. 

Install a water submeter on the make-up water line and monitor water use.  Tracking water use with a submeter makes it easier to identify unintended water use. Commercial customers may also be able to use submeter readings to obtain an evaporation credit on the sewer volume fee. 

Choose your water treatment vendor carefully, emphasizing efficiency and safety.Always work with a certified cooling tower technician to ensure maximum efficiency is achieved while keeping the tower in good condition. 

Ensure that drift eliminators are installed and operating correctly. Drift is water lost as liquid droplets entrained in the exhaust air and is independent of the water lost by evaporation. Drift eliminators not only will this save water and chemicals, but it will also help reduce the chance of spreading Legionella

Regularly inspect or replace ballcock-style fill valves. Ballcock-style valves are prone to leakage and can get out of adjustment, resulting in a continuous overflow to drain, which may go unnoticed. Consider switching to more reliable fill valves, which do not use a ballcock-style float. 

Please call us at 503-823-4527 or email water conservation staff  with any questions!