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Numerical and Theoretical Evaluation of Coupled Metal-Hydride-Based Thermal Storage System with Embedded Helical Tubes
Journal
Energy and Fuels
ISSN
08870624
Date Issued
2022-01-20
Author(s)
Tiwari, Saurabh
Sharma, Pratibha
Abstract
The effective way to sustainably meet the world’s growing need of energy is to harness solar energy. To overcome the intermittent nature of solar energy, a metal-hydride-based thermal energy storage system offers a viable and promising option over sensible and latent heat storage systems, because of its high storage density and lesser requirement of space. In this study, a metal-hydride-based thermal energy storage system is developed using Mg2Ni and LaNi5 as high-temperature (HTMH) and low-temperature metal hydride (LTMH) materials, respectively. The study is done for discharging cycle where hydrogen is desorbed from an LTMH reactor and absorbed in an HTMH reactor. Furthermore, the heat transfer fluid (HTF) therminol VP1 and water are used to recover and to supply heat to HTMH reactor and to LTMH reactor, respectively. The HTF is allowed to flow through helical tubes embedded inside these metal hydride reactors. A three-dimensional (3-D) mathematical model is developed and simulated using COMSOL 5.3 a to effectively study this thermal storage system. The effect of various parameters on the outlet temperature of HTF coming out of a helical tube embedded inside an HTMH reactor is analyzed. Furthermore, based on this parametric study, a detailed energy analysis of the system is also done to analyze its performance. The results showed that increasing the temperature of HTF flowing through a helical tube embedded inside an LTMH reactor increases the outlet temperature of HTF coming out from helical tube embedded inside an HTMH reactor. The system is able to deliver HTF at a temperature above 590 K for more than 5 h with a maximum increment in temperature of 41 K. The results also showed that the system recovered a total energy of 1.22 MJ with a storage density of 144.7 kWh/m3 and with an overall efficiency of 69% in a time period of 6 h.
Volume
36