DEVELOPMENT AND EXPERIMENTAL TESTING OF A FIXED BED ADSORPTION SYSTEM FOR DEEP DEHUMIDIFICATION

Dehumidification of air is extremely important in several contexts. Elevated water vapor concentrations can create a variety of problems, including low thermal comfort, increased bacterial growth, and reduction of quality in daily products storage. In this context, there is a huge need of experimental proofs of devices that can achieve high dehumidification level, guaranteeing supply air with humidity ratio < 5 g/kg. The aim of the present work is to present the design and experimental realization of such a device. It includes 2 stages: an adsorption stage followed by a condensation stage. The adsorption stage consists of an air-water aluminium heat exchanger filled with a composite material composed by silica gel/CaCl2 25% realized by wet impregnation. The employed material has a cost lower than 2 €/kg and the production process can be easily scaled for large quantities. The condensation stage consists of an air-water aluminium heat exchanger connected to a reversible heat pump, which circulates water at temperatures of 2-15°C. The combination of both thermal and electric stages allowed reaching outlet air humidity ratio as low as 4 g/kg. A dedicated experimental campaign was carried out to evaluate the effect of air velocity, heat transfer fluid temperature in the condensation stage and adsorption temperature in the adsorption stage. Re-sults showed that low air flow rates improve the adsorption capacity, whereas temperatures for adsorption and condensation lower than 12°C do not yield any significant improvement in the system performance.