The dynamics of water vapour adsorption on silica gel coated on the metal pipe surface is studied. Those systems in which silica grains were used to coat the heat-exchanger pipes were utilized for heat-transfer enhancement in adsorption chillers. A mathematical model of this process, which takes into account the adsorption kinetics, is proposed. Experimental results for different gas velocities are presented in the form of breakthrough curves. They are used to verify the model and to determine the values of parameters characterizing the adsorption kinetics. The model is applied to predict the spatial and temporal variations of water concentration in the adsorbent layer (grains) covering the pipe and to determine the contribution of the internal mass transfer resistance (in grains) to the total mass transfer resistance (in both phases). It is revealed that the external resistance (in gas) is dominant over the internal resistance and that the contribution of the internal resistance increases with both time and gas velocity.
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