Numerical modelling of water sorption isotherms of zeolite 13XBF based on sparse experimental data sets for heat storage applications. (15th October 2017)

• Record Type: Journal Article
• Authors: Semprini, Simone; Lehmann, Christoph; Beckert, Steffen; Kolditz, Olaf; Gläser, Roger; Kerskes, Henner; Nagel, Thomas
• Is Part Of: Energy conversion and management. Volume 150(2017)
• Page Start: 392
• Page End: 402
• Publication Date: 2017-10-15
• Subjects: Water/zeolite adsorption -- Equilibrium characterization -- Thermal energy storage -- Sparse experimental data; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2017.08.033
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Error analysis when using sparse experimental data to model zeolite 13X. Reconstruct all adsorption equilibria from only three adsorption isotherms. Temperature ranges for those three isotherms are recommended. Empirical equation fits zeolite 13X's characteristic curve accurately. Characterization of heat storage potential with reduced experimental effort. Abstract: This study analyzes the possibility of determining the parameters of an adsorption equilibrium model based on a reduced number of isotherms for the working pair water/zeolite 13X. The employed models rely on the Dubinin-Polanyi theory of micropore adsorption. The reliability of the adsorption equilibrium model based on sparse data is evaluated in terms of the error in the adsorption equilibrium and in terms of the error in loading lift and heat storage density for an adsorption cycle typical for heat storage applications. It is found that as little as three measured adsorption isotherms are sufficient to yield a description of the adsorption equilibrium of zeolite 13X in a wide pressure and temperature range, if the following criteria are obeyed: (i) the measured isotherms should cover the entire range of the characteristic curve and (ii) it is recommended to include isotherms at temperatures close to the working cycle limits. Based on these considerations, temperature ranges for the experimental determination of a reduced set of adsorption isotherms are recommended that yield a reliable description of the adsorption equilibrium in a wide pressure and temperature range. Thereby it is demonstrated that the experimental effort can be reduced significantly while maintaining the predictive capability of the theoretical model.