Desiccants are used in the process industry for the drying of technical gases. An emerging application is fresh water production from water vapor of atmospheric air using adsorbents in a day-night cycle. Water adsorption is performed at night and desorption using solar heat during daytime. In this paper a non-isothermal kinetic model of a packed bed of desiccant pellets is developed to determine possible uptake improvements by elucidating the complex mass and heat transfer interdependent resistances. Shallow beds thinner than 1 cm are required to handle bed diffusion and thermal conduction effects. Options for improvements regarding intragranular water vapor diffusion are limited. The adsorption process quickly becomes convection and radiation limited by the strong exothermicity of water adsorption.