AWT: GSA Guidance for Cooling Towers

From 2014 to 2017, the average water rates paid by the U.S. General Services Administration (GSA) increased 41%. Rapidly escalating costs, federally mandated water-reduction targets, and the fact that 80% of GSA floor space is conditioned with chilled water plant cooling towers led GSA's Proving Ground to select six alternative water treatment (AWT) technologies for in-field validation. This report summarizes the first four evaluations, which were conducted by the National Renewable Energy Laboratory (NREL). Two additional evaluations will be completed by 2021. View full-size infographic. [PDF - 282 KB]

GPG Findings 038, December 2018, Electrochemical Cooling Tower Water Treatment. Opportunity: How much water 
  do cooling towers routinely blow down? UP TO 50% of Cooling water is flushed To minimize scale build-up. Technology:How do Alternative Water Treatment (AWT) systems work? Increase CoC  (cycles of Concentration)while controlling scale & corrosion.AWT systems hold minerals in suspension at increased CoCs 
  Measurement and Verification. Where did M and V occur? National renewable energy Laboratory (NREL) has assessed four AWT systems, three at the Denver Federal Center and one in Savannah, Georgia. Two more assessments are underway with results due in 2020. Results: How did the four AWT systems  perform in M&V? 26% Average WATER SAVINGS Savings ranged from 23%-32%; blowdown reduced 94%-99%. 50% reduction in tower cleaning due to less scale and corrosion. MET GSA WATER STANDARDS Including controlling for legionella. 2-3 Year payback @ GSA avg. water/sewer $16.76/kgal Deployment: Where do the assessments recommend deploying AWT systems? CONSIDER FOR ALL COOLING TOWERS Anticipate changes needed to O&M contracts to transition from traditional chemical treatment to alternative water treatment systems [PDF - 282 KB]


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Last Reviewed: 2020-01-27