Water loading lift and heat storage density prediction of adsorption heat storage systems using Dubinin-Polanyi theory-Comparison with experimental results

Simulating adsorption-based heat storage devices requires knowledge of both the adsorption equilibria and the adsorption enthalpies of the adsorbent materials involved. The Dubinin-Polanyi theory of micropore filling can be used as a tool to reduce the experimental work for the thermodynamical characterization of various adsorption working pairs. In particular it can be used for the deduction of adsorption enthalpies from adsorption equilibrium data. In this work we assess if this theory can be employed to predict the outcome of experiments performed on a lab-scale heat storage device. For that purpose, we present a numerical model of the sorption chamber, which describes the sorption behavior by means of the Dubinin-Polanyi theory. The simulated heat storage densities and water loading lifts are compared to experimentally determined data of two granulated zeolite samples, namely a zeolite Na-X and a zeolite Ca-X, under various humidity conditions.