Tuesday, April 13, 2010

ASHRAE Report Confirms Funk in Cooling Towers

ATLANTA –New research supported by ASHRAE indicates that non-chemical devices (NCD) marketed to control the growth of biological agents, such as Legionella in cooling towers, may not materially reduce biological growth.

Research project No. 1361, Biological Control in Cooling Towers Using Non-Chemical Water Treatment Devices, a two-year project recently completed by Dr. Radisav Vidic at the University of Pittsburgh, evaluated  five  non-chemical devices using different technologies to control biological activity in a model cooling-tower system.  The devices studied included a hydrodynamic cavitation device, pulsed and static electric field devices, an ultra-sonic device and a magnetic device.

In Dr. Vidic’s research, none of the non-chemical devices measurably reduced planktonic or sessile microbial populations in comparison to no-treatment tests and to a conventional chemical microbial control treatment protocol.  The findings appear to be inconsistent with previous research by non-chemical device manufacturers and some independent researchers on some of the same devices tested in the ASHRAE study.  Those other studies reported measurable degrees of biological control within the parameters of testing conducted.

“These results suggest that equipment operators, building owners and engineers should consider taking more frequent water sample tests for their systems that rely on NCDs for biological control. If the testing shows an issue, one possible measure is to add  chemical treatment capability to their system to prevent a potential health hazard from developing until additional research and field testing can resolve this question,” according to  Dr. Vidic .

The study results are still subject to final approval by the sponsoring technical committee, TC 3.6 – Water Treatment.  ASHRAE anticipates formal approval and the release of the final report for this project at its 2010 Annual Meeting Conference in June. Original link here.

1 comment:

Cooling Tower Chemicals said...

The purpose of a cooling tower or condenser system is to reuse water and reduce water usage. Determining the conductivity set point of the water systemis important to maximumyour water reuse. Conductivity is the electrical resistance measurement of the dissolved solids, suspended solids, and dissolved gases of the water and is expressed in mico ohms (uomhs).