US cooling body Ashrae has withdrawn a controversial report apparently questioning the effectiveness of non-chemical water treatment devices in cooling towers.
Ashrae said it had withdrawn the statement reported in last month’s RAC, “pending further review”.
The body said it had received “numerous” comments and questions concerning its report relating to the research project Biological Control in Cooling Towers Using Non-Chemical Water Treatment Devices.
It added that its Technical Committee, responsible for the project TC 3.6 Water Treatment, had not yet
reviewed the final report and was expected to vote on its approval before the end of June.
The review is likely to centre on the research project’s use of a “very small Plexiglas model of a cooling tower” in place of an actual full-scale cooling tower operating in a working cooling system.
Although Ashrae noted use of such models was common in such experiments, it noted “significant variances” between the preliminary results of the study - which concluded that nonchemical devices did not materially control biological growth - and actual field results recorded by non-chemical device manufacturers.
This aspect, the body concluded, may indicate the need for further research.