The Effect of Wind Screens on the Performance of an Induced Draft Air-Cooled Condenser Under Windless and Windy Conditions

Abstract

Wind generally reduces the thermal effectiveness of air-cooled condensers (ACCs). Therefore, this study investigates wind screens as a means to improve the performance of a 20-fan induced draft ACC under windy conditions. Two wind-screen configurations are tested: walls extending above the fan platform (termed wind walls), and walls extending below the fan platform (termed wind skirts). The performance of this five-by-four ACC is evaluated using the open-source computational fluid dynamics code, OpenFOAM. The performance is first analyzed under windless operating conditions and then when the ACC is subjected to wind speeds of 3, 6, and 9 m/s directed along the shorter and longer axes of the ACC. Under windless conditions, wind walls increase the ACC's thermal effectiveness by 1.0 %. Wind skirts, however, reduce the effectiveness by 1.8 %. Depending on the wind speed and direction, wind walls increase the mean thermal effectiveness of the ACC by 0.3 to 3.9 % under windy conditions. Wind skirts, on the other hand, are only beneficial at higher wind speeds: At 3 m/s, the effectiveness declines by 1.4 to 2.1 %; at 6 m/s, the change in effectiveness ranges from -0.4 to 2.2 %; and at 9 m/s, the effectiveness increases by 2.4 to 3.8 %. Wind walls are therefore considered more effective than wind skirts for the tested range of wind speeds.