Preliminary experimental and numerical analysis of a silica gel packed bed humidification system

In this research, an innovative air humidification system based on two packed beds made of silica gel spherical particles is developed. Each bed is alternatively crossed by two airflows (regeneration and process). The first air stream, at outdoor conditions, after being heated and humidified through the sorption material, is supplied to the building. The second one, also at outdoor conditions, provides water vapour to the desiccant packed bed. The system design and optimization is carried out through a numerical and experimental approach. The developed phenomenological model is based on the Pseudo Gas-side Controlled (PGC) method, considering only the gas side resistance and, therefore, assuming uniform water content and temperature distribution within the desiccant particles. A test rig to evaluate performance of the packed bed humidification system has been realized and experimental results have been used to validate the model. Obtained performance highlights that the proposed system can provide adequate humidification and that it can be a valid alternative to conventional adiabatic and steam humidifiers.