Design and analysis of an original multi-bed dehumidifier used for air-conditioning prototype powered by solar energy

Abstract

This work deals with the mass and heat transfer of water/silica gel in both adsorption and desorption modes. An original dehumidifier system, based on a circular repetition of several silica gel beds, is proposed as a feasible alternative to the classical dehumidifier systems. Thanks to an appropriate working order ensuring an optimal synchronization between different beds, the proposed design permits regularization of the air humidity ratio and air temperature in the outlet of the dehumidifier system. The simulation of adsorption and desorption modes are carried out for one typical bed. Combined mass and energy differential equations are numerically implemented using the finite-volume method in order to simulate the effect of operating conditions on the temporal behavior of both silica gel moisture content, adsorbent temperature, and air humidity ratio. The obtained results are then presented and interpreted. The rise of humid air temperature (in adsorption mode) and its drop (in desorption mode), in return for each 1 g (0.0022 lbm) of adsorbed water vapor and desrobed water, are quantified. The specific heat gained (in adsorption mode) and lost (in desorption mode) by humid air is also evaluated.

Acknowledgments

Rached Nciri, PhD, PE, is Technologist. Chaouki Ali, PhD, PE, is Assistant Professor. Habib Ben Bacha, PhD, PE, is Associate Professor.