InterPore2026

Multiscale Modeling of Vacuum Based Thermochemical Reactors for Residential Heat Storage Using In-Situ Micro-CT

20 May 2026, 10:05

1h 30m

Poster Presentation (MS09) Pore-Scale Physics and Modeling Poster

Speaker

Dr Amirhoushang Mahmoudi (University of Twente)

Description

Decarbonizing residential heating is a critical challenge in the energy transition, as the sector remains heavily reliant on fossil fuels. To enable a shift toward sustainable heating, efficient storage systems are required to bridge the gap between intermittent renewable supply and domestic demand. Thermochemical energy storage (TCES) using sodium sulfide (Na2S) offers a compelling solution, providing a high volumetric energy density of 2.79 GJ/m3. To maximize performance and stability, these systems are operated under vacuum conditions. This absence of non-condensable gases is crucial for Na2S, as it prevents unwanted secondary reactions with CO2. Additionally, the vacuum environment enhances vapor transport kinetics. However, a significant downside is the reduction in heat transport, as the lack of a gas medium limits conduction primarily to particle-particle contact points.
This trade-off is further complicated by the dynamic nature of the porous salt bed. The material undergoes substantial volume changes during hydration and dehydration, continuously altering the bed’s morphology and thus its transport properties. This work presents a comprehensive multiscale workflow to quantify these morphological effects on reactor performance.
First, a specialized vacuum-compatible reactor was developed for in-situ X-ray micro-computed tomography (micro-CT). This setup allows for the non-destructive visualization of the Na2S bed under realistic operating conditions (12 mbar vapor pressure), capturing the evolution of particle connectivity, porosity, and volume expansion during cycling.
Second, the acquired micro-CT images are directly used as the computational domain for pore-scale simulations to determine effective transport properties. Using GeoChemFoam we perform detailed physics simulations on the evolving pore geometry. The effective thermal conductivity is calculated by solving the steady-state heat equation, while the effective permeability is determined by solving the Darcy-Brinkman-Stokes equations for flow through the complex pore space.
Finally, these property values are upscaled into a more computationally efficient continuum model. This model solves for the reaction kinetics, heat transport, and vapor transport on the reactor scale. By integrating real-time morphological data into the reactor scale, this approach provides critical insights for optimizing high-density thermal batteries, supporting the development of efficient technologies for residential heat decarbonization.