Parameter analysis to improve rotary desiccant dehumidification using a mathematical modes

Waves analysis using psychrometric chart, a method aiming to evaluate the rotary desiccant dehumidification, is presented in this paper. The continuity and energy conservation equations for the transient coupled heat and mass transfer are established and solved using a finite differential model. The locus of points of outlet air states along the rotational direction may be plotted as two wave fronts and one breakthrough point for both dehumidification and regeneration processes. Thermal wave, concentration wave, and middle zone point are explained in terms of the different characteristics of their own. The rules to improve the performance of dehumidification according to the wave shape are proposed and some important parameters, such as heat capacity, adsorption heat, rotation speed, regeneration temperature, thickness of the desiccant matrix and the desiccant isothermal shape, are discussed in detail using psychrometric chart. It is demonstrated that the chart method is feasible and rapid in evaluating the performance of the rotary dehumidifier. (C) 2001 Editions scientifiques et medicates Elsevier SAS.