Integrated theoretical model for performance evaluation of flat-sheet membrane-based absorptive dehumidification module using lithium chloride-water solution

This paper presents an integrated theoretical model to evaluate the performance of a flat-sheet membrane-based absorptive dehumidification module with different flow arrangements (i.e., cocurrent, countercurrent, and cross flow configurations) using an aqueous lithium chloride desiccant. The model results showed good consistency with experimental data, with a maximum relative error of approximately 7%. The performance of the flat-sheet dehumidification module was evaluated for various air and solution channel heights ranging from 1 to 5 mm at a constant Reynolds number in both channels, in terms of sensible, latent, and total effectivenesses. The sensible effectiveness increased with a decrease in the air channel height and an increase in the solution channel height; in particular, the effect of the solution channel height was more pronounced in the cocurrent flow configuration. In addition, the latent effectiveness increased with a decrease in both channel heights. Thus, there was a trade-off between the effects of the solution channel height on the sensible and latent effectivenesses; consequently, the effect of the solution channel height on the total effectiveness was mitigated. The total effectiveness was observed to decrease in the order of countercurrent, cross-, and cocurrent flow configurations; here, its value in the countercurrent flow configuration was approximately 0.788 when both channel heights were 1 mm.