Dynamics of water vapour sorption on composite LiCl/(silica gel): An innovative configuration of the adsorbent bed

Adsorption Heat Conversion (AHC) is energy and environment saving alternative to conventional compression systems. The growth of specific power of AHC systems is a prerequisite for the wider spreading of AHC. To enhance the power, an innovative adsorbent bed configuration was suggested, namely, a compact adsorbent layer prepared by gluing to heat exchanger surface ready-made grains instead of uniform adsorbent coating. The main goal was a comparative study of water sorption dynamics on loose and glued grains of a composite LiCl/ (silica gel) to evaluate the power enhancement. The grains were glued to aluminium foil with various binders, both organic and inorganic, the effect of the binder nature was studied. The effective heat transfer coefficient was evaluated under typical conditions of adsorption chilling cycle. The main findings are: (a) the effective heat transfer coefficient is increased up to 1.5 times when using inorganic binders; (b) organic binders do not affect heat transfer; (c) heat transfer intensification leads to accelerating initial stage of the ad/desorption; (d) at longer times, a desorption slowdown is observed due to hindered mass transfer or LiCl crystallisation. The factors controlling the adsorption kinetics are determined and recommendations are formulated for designing innovative bed configuration.

Automated summary

Adsorption Heat Conversion (AHC) is an energy-saving and environmentally friendly alternative to conventional compression systems. The use of innovative adsorbent bed configurations, such as gluing ready-made grains to the heat exchanger surface, can enhance the power of AHC systems. Inorganic binders are found to increase the effective heat transfer coefficient, while organic binders have no effect on heat transfer. The findings provide insights into the factors controlling adsorption kinetics and offer recommendations for designing innovative bed configurations.