Modified Effectiveness Model for Crossflow Packed-Bed Humidifiers
Keywords:Humidifier, Cross-flow, Packed-bed, Effectiveness, Analytical model, Heat capacity ratio.
A model for the energy effectiveness of cross-flow packed-bed humidifiers is developed and compared with experimental data. The effectiveness of the humidifier is defined as the sensible and latent heat transferred to the air to the maximum total energy available to the humidified air. Simultaneous heat and mass transfer models; available in the literature and originally developed forwent counter flow cooling towers, are utilized to develop a modified model in this paper. The main modification added to that model is a definition of the heat capacity ratio that combines the simultaneous heat and mass transfer transport in that cross-flow packed-bed humidifiers. It was found that the mixed-mixed crossflow heat exchanger effectiveness relationship developed by Kays and London agrees well with the experimental data with an average deviation of less than 10%. The mixed-unmixed correlation developed by Kays and London  which was recommended by Jaber and Webb is found to have larger deviation from the experimental measurements occurred at higher heat capacity ratios.
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