Browsing by Author "Oosthuizen, Pieter Cornelis"
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- ItemPerformance characteristics of hybrid cooling towers(Stellenbosch : Stellenbosch University, 1995-09) Oosthuizen, Pieter Cornelis; Kroger, D. G.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: Different wet/dry and dry/wet cooling tower configurations are investigated and the advantages and disadvantages of separate and combined (hybrid) configurations are discussed. Some existing hybrid towers are also discussed. The different plume prediction models that are found in the literature are investigated and the psychrometries behind the formation of visible plumes are discussed. Psychrometric models are given for a few different plume abatement tower geometries. A theoretical model is developed with which the thermal performance of hybrid towers can be predicted. This theoretical model makes use of adapted wet and dry cooling tower theories. A computer program was developed to determine the thermal performance of a parallel path air flow and series path water flow rectangular hybrid tower. A sample calculation of the hybrid tower solution, in which the converged values are used, is given. A wet cooling tower fill for use in the hybrid tower was tested, from which correlations for the transfer characteristics and the pressure drop coefficients were generated. Sample calculations to show how the transfer characteristics and the pressure loss coefficients were obtained from the experimental data are given. The Chebyshev method of numerical integration, that was used to determine the transfer characteristics, is discussed. A method for determining a more appropriate and accurate pressure loss coefficient is derived. Experiments were done on cylindrical and rectangular model cooling tower sectors to determine the size of the inlet circulation areas. Correlations with which the size of the ineffective fill area in wet cooling towers can be predicted were obtained from the experimental data.