Combined air-cooled condenser layout with in line configured finned tube bundles to improve cooling performance

Abstract

Air-cooled condensers (ACCs) are commonly arranged in the A-frame form to extend the heat transfer surface with some well-recognized design flaws that inhibit the cooling performance. For overcoming this geometric defect, the combined natural draft ACC is proposed with the horizontally in line arranged finned tube bundles inside the dry-cooling tower and vertically in line configured bundles outside the tower. A three dimensional CFD method with the realizable k-ε model, radiator model and porous media model is developed and experimentally validated. The thermo-flow characteristics of the proposed ACC are analyzed and compared with two types of traditional ACCs. Besides, the effects of the platform heights from 5 m to 50 m are also investigated for the novel ACC layout. The results show that the new proposed ACC can endow with splendid cooling performance at the wind speeds lower than 9 m/s, especially in the absence of winds with the heat transfer rate increased by nearly 20% in comparison with two conventional ones. While at high wind speeds, the traditional ACC with vertically arranged heat exchanger bundles shows the highest cooling efficiency, thus is applicable to the regions with strong prevailing winds. Moreover, for the novel ACC, there exist the optimal platform heights of 15 m and 40 m at the low wind speeds and high wind speeds respectively, which can contribute to the optimal design of natural draft air-cooled condenser in power plants.