Finite Element Modeling of Atmospheric Water Extraction by Way of Highly Porous Adsorbents: A Roadmap for Solver Construction with Model Factor Sensitivity Screening

A finite element model (FEM) is developed for use in determining adsorption system performance. The model is intended to guide novel adsorbent structure fabrication and atmospheric water harvesting device design. We survey a variety of governing equation factor inputs and relationships which describe the interaction between zeolite 13X and water vapor. Mitigation strategies are discussed for detecting the breakdown of continuum modeling at the microscale wherein Knudsen effects and other anomalous behaviors emerge. Characterization of model factor inputs and the techniques for their sourcing is described with consideration to the construction of a high throughput multiscale shape optimized computational schema. Four objectives guided the development of this model. Our first objective was to understand the implementation of adsorption system equations and the assumptions that could prevent reliable predictability. The second objective was to assemble, reduce, and analyze model constants and approximations that express FEM coefficient calculations as physical forces and thermodynamic properties which could be derived from other computational methods. Third, we analyzed factor sensitivity of model inputs by way of a 2(k) factorial screening to determine which inputs are driving the physics of water harvesting adsorption systems. The fourth objective was to design the FEM solver for integration into a multiscale high throughput topologically optimized schema. The main finding of the solver factor screening indicates that total micropore volume has the highest value characteristics in relation to water uptake.

Automated summary

A finite element model is developed to determine the performance of adsorption systems and guide the design of novel adsorbent structures and atmospheric water harvesting devices. The interaction between zeolite 13X and water vapor is described using various equation factors and relationships. Mitigation strategies are discussed to address anomalous behaviors at the microscale. The sensitivity of model inputs is analyzed and the total micropore volume is found to have the highest correlation with water uptake.