Predicting cooling tower plume dispersion

An assessment of the effects of visible cooling tower plumes on the local environment can be a necessary part of any proposal for a new large industrial process. Predictions of the dispersion of plumes from cooling towers are based on methods developed for chimney emissions. However, the kinds of criteria used to judge the acceptability of cooling tower plumes are different from those used for stack plumes. The frequency of long elevated plumes and the frequency of ground fogging are the two main issues. It is shown that events associated with significant plume visibility are dependent both on the operating characteristics of the tower and on the occurrence of certain meteorological conditions. The dependence on atmospheric conditions is shown to be fairly complex and simple performance criteria based on the exit conditions from the tower are not sufficient for assessments.