A Simplified Model Of Heat And Mass Transfer Between Air And Falling-Film Desiccant In A Parallel-Plate Dehumidifier

A simplified model is developed to predict the heat and mass transfer between air and fallingilm liquid desiccant during dehumidification in a parallel-plate absorber. Compared to the second-order partial differential equations that describe fluid motion, first-order, non-coupled, ordinary differential equations are used to estimate the heat and mass transferred and explicit equations are derived from conservation principles to determine the exiting conditions of the absorber for different flow arrangements. The model uses a control volume approach that accounts for the change in desiccant film thickness and property values. The model agreed with a more complicated parallel flow model in literature. Using existing experimental data for a counterflow arrangement the model was validated over the range of input variables at the level of 8% for varying inlet desiccant flow rates and 10% for varying inlet air mass flow rates when an experimentally determined mass transfer coefficient was used in the model