On the dimensional analysis of a cross-flow flat-plate membrane liquid desiccant dehumidifier

The membrane liquid desiccant dehumidification has been proposed to resolve the carry-over problem of the conventional liquid desiccant dehumidifiers (e.g. packed-bed, spray chamber, etc.). Many earlier studies have been devoted to developing different types of membranes and investigating the operating conditions to achieve sufficient dehumidification performance. However, the key governing factors that control the dehumidification process have never been explored and their impacts remain uncertain. In this paper, a dimensional analysis of the cross-flow flat-plate membrane liquid desiccant dehumidifier is carried out to promote in-depth understanding of the fundamental dehumidification process and to investigate its dominant physical mechanism. A membrane liquid desiccant dehumidifier prototype has been developed and tested under different conditions. A 3-D CFD model is formulated to predict the heat and mass transfer performance of the dehumidifier, and its dimensionless form is developed via an appropriate scaling analysis. The relative importance of the relevant dimensionless groups in the dehumidification process is discussed, and correlations are developed to predict and optimize the dehumidified air conditions.