Heat and mass transfer performance analysis of a compact, hybrid liquid desiccant absorber

Modeling and performance analysis of a compact hybrid liquid desiccant absorber is carried out in this work. The proposed absorber can be described as a direct contact heat and mass exchanger with several flow passages separated from each other by thin plates. Each thin plate, besides separating the water-air passage from the solution-air passage, also provides contact area for heat and mass transfer between the fluids flowing in each passage. A sensitivity analysis for process air at 32°C, 0.022 kg/kg and return air at 23°C, 0.009 kg/kg using a lithium chloride solution was performed in this study. Performance showed a strong dependence on the physical size of the absorber, the solution concentration, and the ratio of cooling to process air mass flow rate. However, negligible differences were found between the performance of a parallel and a counter flow arrangement. Finally, it was concluded that the proposed absorber will not offset both the latent and sensible load of the process air, and therefore an auxiliary cooler will generally be required to meet the sensible load in a typical comfort application