Design and performance evaluation of a multilayer fixed-bed binder-free desiccant dehumidifier for hybrid air-conditioning systems: Part I – experimental

A novel multilayer fixed-bed binder-free desiccant dehumidifier (MFBDD) was designed as part of this study, to be operated in combination with a conventional vapor-compression system to attain higher moisture removal capacity with lower electricity consumption. Silica-based high-purity spherical gel, Micro Sphere Gel (M. S. Gel), of 2.7 nm pore diameter and exhibiting an S-shape isotherm was used as adsorbents during the experiment. Transient adsorption, heat transfer, and pressure drop characteristics of the proposed device were evaluated experimentally for varying process air velocity, process air humidity, and desiccant bed thickness. The results revealed that while the pressure drop of the proposed device was approx. 98% lower, the average dehumidification capacity (during first 10 min of adsorption) was approx. 36% higher compared to a conventional desiccant wheel. Multilayer desiccant beds with adequate process airflow channel height and the usage of adsorbents without polymer binders in innovative sheet-type beds has led to such lower pressure drop and improved dehumidification capacity of the device.