The use of direct dry cooled condensers for condensing steam from a power station steam turbine, is prompted by the shortage of water in remote areas where rich coal fields often exist. Direct dry cooling can be accomplished by using a natural or a forced draught condenser system. Forced draught systems make use of fans and a finned tube heat exchanger to provide the cooling mechanism. The largest direct forced draught Air Cooled Condenser (ACC) in the world is situated in South Africa and consists of six 960 MW condensers. Ambient conditions such as temperature and wind speed have a major effect on the performance of such an ACC and in some instances can be detrimental to the reliability and availability of an ACC. Performance optimisation for such a system is extremely difficult due to the enormous size of the structure involved and the dynamics of the prevailing ambient conditions. This paper presents a numerical model which has been developed making use of Computational Fluid Dynamics (CFD) to model the ambient conditions and the effect which they have on the performance of an ACC system. The various components of the model are discussed and results are presented for a single case study.
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