TY - CHAP

T1 - Numerical investigations of a thermochemical heat storage system during the discharging

AU - Fopah Lele, Armand

AU - Hu, Jian

AU - Kuznik, Frédéric

AU - Osterland, Thomas

AU - Ruck, Wolfgang

PY - 2015/5/19

Y1 - 2015/5/19

N2 - Thermochemical materials, particularly salt hydrates, have a significant potential of use in storage systems. When a salt hydrate is heated to a critical temperature, a chemical reaction is initiated to dissociate it into its anhydrous form and water vapour. The anhydrous salt stores the sensible energy that was supplied for dehydration, which can be later extracted by allowing cooler water or water vapour to flow through the salt, transforming the stored energy into higher sensible heat. This work presents the modelling during the thermochemical hydration reaction in the reactive porous bed based MgCl2 in a closed system. An analytical sharp front model is also developed in order to determine the required hydration time and bed size. A sensitivity analysis helps identifying optimal parameters that more significantly influence the performance of the heat release process. Numerical heat and mass transfer through principal system components are studied using Comsol Multiphysics Software. Results show good concordance with the experiment. In this closed system, the inlet vapour pressure into the bed has no influence on the process conversion. The optimal porosity of around 0.76 has been taken based on the heat and mass transfer dilemma analysis. Optimal heat exchanger design reveals critical values to enhance the mass transfer issue in the reactive bed.

AB - Thermochemical materials, particularly salt hydrates, have a significant potential of use in storage systems. When a salt hydrate is heated to a critical temperature, a chemical reaction is initiated to dissociate it into its anhydrous form and water vapour. The anhydrous salt stores the sensible energy that was supplied for dehydration, which can be later extracted by allowing cooler water or water vapour to flow through the salt, transforming the stored energy into higher sensible heat. This work presents the modelling during the thermochemical hydration reaction in the reactive porous bed based MgCl2 in a closed system. An analytical sharp front model is also developed in order to determine the required hydration time and bed size. A sensitivity analysis helps identifying optimal parameters that more significantly influence the performance of the heat release process. Numerical heat and mass transfer through principal system components are studied using Comsol Multiphysics Software. Results show good concordance with the experiment. In this closed system, the inlet vapour pressure into the bed has no influence on the process conversion. The optimal porosity of around 0.76 has been taken based on the heat and mass transfer dilemma analysis. Optimal heat exchanger design reveals critical values to enhance the mass transfer issue in the reactive bed.

KW - Energy research

KW - Thermochemical materials

KW - Heat and mass transfer

KW - Engineering

KW - Heat exchanger

KW - Thermochemical heat storage

KW - Sustainability Science

KW - Efficiency

M3 - Article in conference proceedings

SN - 978-88-98273-17-1

BT - ASME-ATI-UIT 2015 Conference on Thermal Energy Systems: Production, Storage, Utilization and the Environment

PB - Unione Italiana Termofluidodinamica

CY - Napoli

T2 - Conference on Thermal Energy Systems - ASME-ATI-UIT 2015

Y2 - 17 May 2015 through 20 May 2015

ER -