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GPG OUTBRIEF 33
AWT for Cooling Towers Guidance
If you missed the latest webinar on the AWT for Cooling Towers: GSA Water Conservation Guidance, the recording and slides are now available.
Many thanks to the presenters and to the participants for their thoughtful questions, some of which are answered below:
Q: How well do these remedies work to remove and prevent biofilm?
A: The evaluated AWT technologies met GSA water treatment standards. In addition, GSA’s Rocky Mountain Region (Region 8) and Pacific Rim Region (Region 9) reported that the installed AWT system had no impact, either negative or positive, on preventing biofilm. Region 8 noted the importance of optimizing the water flow to prevent stagnation.
Q: How effective are the AWT methods at specifically controlling Legionella growth?
A: There was no evidence of Legionella growth during any of the evaluations. Most of the systems included controllers that monitored water quality and, in addition, the National Renewable Energy Laboratory requested that local water treatment control subcontractors test for Legionella during the evaluations.
Q: Do you need to continue water management with these AWT systems?
A: Yes, water treatment is still required, along with ongoing monitoring and system maintenance. None of these AWT systems are set-and-forget. The water treatment vendor, operation and maintenance personnel, and local facility management staff must all understand the technology to preserve the system.
Q: Were any of the AWT systems tested in a region with higher humidity that can affect bacterial growth?
A: We evaluated an AWT system in Georgia, and one of the AWT technology vendors is based in Florida.
Q: What is the water rebate availability for AWT systems?
A: We do not know the entire rebate landscape but one AWT vendor reported that it has received rebates in California, Nevada, and Arizona. We recommend that the project team investigate the availability of water rebates before installation. To take advantage of rebates, it’s important to have metering in place for makeup and blowdown water to measure water savings. AWT for Cooling Towers: GSA Water Conservation Guidance provides best practices for metering cooling tower water use.
Q: Where can we find more information on the AWT technologies or solutions that GSA evaluated?
A: Appendix A of the AWT for Cooling Towers: GSA Water Conservation Guidance provides brief recaps of the six systems evaluated and links to the Green Proving Ground published results. These are still emerging technologies; consult with building ownership and facility management to make deployment decisions.
Reference to any specific commercial product, process, or service does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
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