Demonstration of adiabatic cooling to improve the performance of air-cooled heat exchangers

A demonstration of improved heat exchanger performance by adiabatically cooling the inlet air to an air-cooled heat exchanger was performed on a condenser that had a design heat rejection rate of 58 million Btu/hr. Pneumatic nozzles were used to inject atomized water into the inlet air stream. Mean droplet diameters ranged from 16 to 28 microns for all of the tests. Results of these experiments comparing conventional and adiabatic cooling show that adiabatic cooling does improve heat transfer performance in accordance with expectations. The operation of the system was simple and reliable. Visual observations of the heat exchanger showed that finned surfaces remained dry even when enough water was added to saturate the inlet air. With the use of efficient atomizers, adiabatic cooling improves efficiency at a steam-electric power plant without increasing dry cooling tower size, and thereby avoids the need to reduce plant output during hot weather.