Effects of Airflow Profile and Condensation Pressure on Performance of Air-Cooled Condensers

Abstract

The effect of airflow profile and condensation pressure on the performance of air-cooled condensers is investigated experimentally. Two large, flattened-tube air-cooled steam condensers are studied. The tube lengths are 10.7 and 5.7 m, with inner dimensions of 216 × 16 mm and aluminum fins on each side of the elongated-slot cross sections. Capacity and pressure drop are measured and discussed here. All tests are performed with a horizontal tube and co-current vapor and condensate flow. Four different profiles of cross-flowing air are tested: uniform air flowing upwards, uniform air flowing downwards, and two profiles of non-uniform air flowing upwards. For the 10.7 m tube, reversing airflow direction from upwards to downwards is found to significantly increase condenser capacity. Also for the 10.7 m tube, a favorable non-uniform air-velocity profile is shown to increase capacity in comparison to a uniform air-velocity profile. Both of these performance increases are shown to be the result of matching regions of maximum heat transfer coefficient on the air and steam sides. For the 5.7 m tube, a non-uniform airflow profile is shown to have no effect on capacity. Reducing condensation pressure is shown to decrease condenser capacity for both condenser tubes.