Experimental results on adsorption beds for air dehumidification

• Experimental analysis on dehumidification performance of silica gel packed beds has been carried out.
• Pressure drop test of packed bed configurations and validation against Ergun model has been studied.
• High adsorption capacity can be achieved with very low regeneration temperature.
• Cooling during the adsorption process allows higher dehumidification performances.

Desiccant rotors are commonly used in large scale solar cooling open cycle applications. As is well known, adsorption heat sensibly reduces the dehumidification capacity of the desiccant material and results in lower system performance. The aim of this work is to describe an innovative solution that permits simultaneous mass and heat transfer. In particular, two components working with silica gel fixed beds were studied and compared. The first component is a simple packed bed containing silica gel grains. The second component is a fin and tube heat exchanger commonly used in several air conditioning applications wherein the spaces between the fins are filled with silica gel grains. In this case, the adsorption material is cooled through a recooling loop. For both solutions, results are presented in terms of dehumidification performances versus operation time, storage of adsorption capacity and energy required for the regeneration of the desiccant.