Experimental and Theoretical Study of an Internally Cooled Liquid Desiccant Dehumidifier

Liquid desiccant dehumidifiers are useful for simultaneously recovering heat and water from flue gas. Internally cooled dehumidifiers are generally superior to adiabatic dehumidifiers in terms of the consumption of the desiccant and the size of the equipment required. This study examines the performance of a counter-flow dehumidifier through experiments and simulations under different operating conditions, and analyzes the moisture effectiveness and enthalpy effectiveness as performance indices. By applying correlations from the literature, the theoretical model can predict the performance of the dehumidifier within an acceptable range of accuracy. According to the experimental results, droplets were visible at a low desiccant flow rate when the velocity of the gas was above 4.88 m/s. Moreover, a higher cooling ratio and a higher temperature of the solution enhanced the effectiveness of the dehumidification. A temperature cross occurred between the gas and the solution when the mass transfer was sufficiently high, which reflects better heat transfer performance than the conventional convective heat exchanger.