Evaporative cooling towers

Cooling towers are heat exchangers used for dissipating large quantities of heat into the atmosphere. They are important components in many industrial and commercial processes. The evaporative cooling towers use the latent heat of evaporation of water to exchange heat from the process and the air which flows within the tower. This kind of tower emits into the atmosphere large quantities of vapour and water drops of different sizes (drift) . The water drops contain, with varying concentrations, the same impurities contained in the cooling water, hence they are potentially dangerous when they deposit on a surface.

For example, if sea water is used for cooling, the drift water will contain salt. Therefore the greater drops, which will fall close to the tower, will be dangerous for the industrial plant, since they can generate corrosion of the equipments or short-circuit in the electric plants. On the other hand, the smallest drops, which will fall far from the tower, can be dangerour for the coltures.

Other environmental impacts of the cooling towers are due to the huge vapour quantity emitted into the atmosphere. The production of a large visible plume induces a decrease of the solar radiation below the plume itself, with possible damages for the coltures. The fog episodes can also increase, so as the episodes of ice formation on the roads.

Enviroware studies the atmospheric impact of cooling towers considering all the above mentioned problems. Enviroware uses simulation models capable to predict the deposition field of the impurities contained in the drift (WETPLUME, SACTI). The modelling results allow, for example, during the construction of a plant, to determine the safe distances for the installation of equipments (pumps, electric generators, ...) which could be damaged from the impurities contained in the water. The models also allow to determine the impact of the cooling tower emissions outside the plant perimeter, as for example the damages to the coltures and the probability of formation of fog and ice.