Performance investigations on hydrogen-based thermochemical energy storage system through finite volume method and thermodynamic simulation

In the present work, thermodynamic simulation and numerical modelling (through a finite volume approach) are carried out to investigate the performance of hydrogen-based thermochemical energy storage (H-TCES) system with the application of LaNi4.6Al0.4-La0.9Ce0.1Ni5 metal hydride (MH) pair. Thermodynamic equations are used to evaluate the H-TCES performance whereas the continuity, energy and pressure equations are solved with the help of the computational fluid dynamics (CFD) approach to predict the heat and mass transfer behaviour of MH beds. The numerical code is validated by comparing the predicted pressure concentration isotherms (PCIs) with the experimentally measured PCIs, which are observed to be in good agreement. The experimental PCI data are used for the performance prediction of H-TCES system operating at 25 degrees C, 100 degrees C, 130 degrees C and 150 degrees C as ambient-, regeneration-, storage- and output temperature respectively. It is found that the energy storage density of the H-TCES system is 243.67 kJ with a COP of 0.48. The overall cycle time is predicted as 2200 seconds, which includes heat storage, heat output, sensible heating and sensible cooling processes. The generated temperature contours illustrate the effect of an increase and decrease in bed temperature during absorption and desorption processes.

Automated summary

In this study, thermodynamic simulation and numerical modelling were used to investigate the performance of a hydrogen-based thermochemical energy storage system using LaNi4.6Al0.4-La0.9Ce0.1Ni5 metal hydride pair. The results showed good agreement between predicted and experimentally measured performance. The H-TCES system had an energy storage density of 243.67 kJ, a COP of 0.48, and a predicted overall cycle time of 2200 seconds.