A study of advanced magnesium-based hydride and development of a metal hydride thermal battery system

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Publication Type dissertation
School or College College of Engineering
Department Metallurgical Engineering
Author Zhou, Chengshang
Title A study of advanced magnesium-based hydride and development of a metal hydride thermal battery system
Date 2015-05
Description Metal hydrides are a group of important materials known as energy carriers for renewable energy and thermal energy storage. A concept of thermal battery based on advanced metal hydrides is studied for heating and cooling of cabins in electric vehicles. The system utilizes a pair of thermodynamically matched metal hydrides as energy storage media. The hot hydride that is identified and developed is catalyzed MgH2 due to its high energy density and enhanced kinetics. TiV0.62Mn1.5, TiMn2, and LaNi5 alloys are selected as the matching cold hydride. A systematic experimental survey is carried out in this study to compare a wide range of additives including transitions metals, transition metal oxides, hydrides, intermetallic compounds, and carbon materials, with respect to their effects on dehydrogenation properties of MgH2. The results show that additives such as Ti and V-based metals, hydride, and certain intermetallic compounds have strong catalytic effects. Solid solution alloys of magnesium are exploited as a way to destabilize magnesium hydride thermodynamically. Various elements are alloyed with magnesium to form solid solutions, including indium and aluminum. Thermodynamic properties of the reactions between the magnesium solid solution alloys and hydrogen are investigated, showing that all the solid solution alloys that are investigated in this work have higher equilibrium hydrogen pressures than that of pure magnesium. Cyclic stability of catalyzed MgH2 is characterized and analyzed using a PCT Sievert-type apparatus. Three systems, including MgH2-TiH2, MgH2-TiMn2, and MgH2-VTiCr, are examined. The hydrogenating and dehydrogenating kinetics at 300 C are stable after 100 cycles. However, the low temperature (25 C to 150 C) hydrogenation kinetics suffer a severe degradation during hydrogen cycling. Further experiments confirm that the low temperature kinetic degradation can be mainly related the extended hydrogenation-dehydrogenation reactions. Proof-of-concept prototypes are built and tested, demonstrating the potential of the system as HVAC for transportation vehicles. The performance of the concept-demonstration-unit show both high heating/cooling power and high energy densities. An extended cycling test shows degradation on the performance of the system. To solve this problem, a metal hydride hydrogen compressor is proposed for aiding the recharge process of the system.
Type Text
Publisher University of Utah
Subject Magnesium hydride; Metal hydride; Thermal energy storage
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © Chengshang Zhou 2015
Format Medium application/pdf
Format Extent 3,748,616 Bytes
Identifier etd3/id/3736
ARK ark:/87278/s67q26qk
Setname ir_etd
Date Created 2016-02-29
Date Modified 2018-04-30
ID 197287
Reference URL https://collections.lib.utah.edu/ark:/87278/s67q26qk
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