Experimental and theoretical investigations on the cyclic operation of TSA cycle for air dehumidification using packed beds of silica gel particles

Abstract

Dehumidification using desiccant beds provide a good alternative for the conventional vapor compression cooling system. Desiccant material in the desiccant dehumidification system should undergo both adsorption and desorption processes. In the present work, experimental tests have been carried out for thermal swing adsorption (TSA) cycle utilizing two packed beds of silica gel spherical particles. The pseudo gas side controlled (PGC) mathematical model has been presented for predicting the cycle performance. The mathematical model has been validated using the experimental results. The root mean square of errors ranges from 1.15% to 9.03% for the exit air humidity ratio and from 1.08% to 9.68% for exit air temperature. The dynamics of desiccant bed during the cyclic operation has been investigated numerically. In addition, it has been found from the parametric study that the cycle efficiency is maximum for a regeneration temperature of 90-95°C when the bed length varies from 50 to 300mm and for desiccant particle diameter ranging from 2 to 5mm. A sensible cooling for the process air before undergoing the dehumidification period is recommended for increasing the cycle efficiency and the dehumidification time which is an added advantage. © 2013 Elsevier Ltd.