Studying the heat and mass transfer process of liquid desiccant for dehumidification and cooling

Abstract

Desiccant-based dehumidification has gained significant attention in recent years to develop the energy efficient hybrid air-conditioning systems particularly for the tropical climate. Thus far, complex and tedious theoretical models have been developed to analyze the heat and mass transfer phenomena involved in liquid desiccant dehumidification processes. In the present study, a simple theoretical model has been presented to quantify the heat and mass transfer rates of the water-cooled liquid desiccant dehumidification and cooling processes for air-conditioning applications. Seven coupled ordinary differential equations have been developed to describe the complex heat and mass transfer processes. As far as the solution approach and practical application are concerned, the governing equations are solved simultaneously using the numerically stable 4th order Runge-Kutta scheme while preserving its accuracy to 6% in construct to full-scale model simulation. The developed model is rationally modified to study the performance of adiabatic dehumidifiers. The dehumidification and cooling performances of the adiabatic and water-cooled dehumidifiers are analyzed over a wide range of operating conditions. Finally, the energy performance enhancement potentials of the hybrid liquid desiccant air-conditioning system have been demonstrated. By analyzing the dehumidification and cooling performance, an energy saving of up to 25% can be achieved using the hybrid air-conditioning systems.