Plume Abatement

Conventional “wet” cooling towers generate visible condensation plumes that form when the hot saturated cooling tower exhaust plume cools in the atmosphere. Plume-abated cooling towers are installed in areas where a visible cooling tower plume is not desirable. Plume-abated cooling towers may be installed near airports or highways where plumes can reduce visibility and lead to safety concerns. Plume-abated towers may also be installed where visible plumes in scenic locations or in locations where industry and residential areas co-exist where visible plumes may be objectionable.

CleanAir performs tests of plume-abated towers under the guidelines of CTI ATC-150 to determine whether the tower will form a condensing plume at the thermal design point.


A typical plume-abated tower is a tower that has two inlet paths to the cooling tower fan. One air inlet path flows through a dry section similar to a car’s radiator, where water flows inside a heat transfer media but does not directly contact the air stream. Air flowing over this media remains dry and picks up heat before flowing into the plenum area below the cooling tower fan. In the plenum area, the hot dry air is mixed with the air coming through the conventional “wet” section of the tower. The two airstreams mix in the exhaust plenum before being exhausted to the atmosphere. The objective of the design is to mix the hot dry air with the saturated wet air from the conventional wet section of the tower so that the combined exhaust is below the saturation point and visible condensation does not occur.