MgSO_(4)·7H_(2)O for thermochemical energy storage:Hydration/dehydration kinetics and cyclability  

作　　者：CHEN Jie MA Hongkun DING Yulong 

机构地区：[1]Birmingham Centre for Energy Storage,University of Birmingham,Edgbaston,BirminghamB152TT,UK

出　　处：《储能科学与技术》2024年第12期4259-4271,共13页Energy Storage Science and Technology

摘　　要：In recent decades,MgSO_(4)·7H_(2)O(epsomite)has attracted significant attention as a promising thermochemical-based thermal energy storage material due to its high theoretical energy density,wide availability,and affordability.Despite extensive research efforts,progress in achieving high-energy density has been limited,primarily due to inadequate understanding of its reaction mechanisms and unfavorable dehydration/hydration kinetics.This study systematically investigated the hydration/dehydration kinetics and cyclability of MgSO_(4)·7H_(2)O.The results reveal that the dehydration process is influenced by the heating rate,with an optimal rate of 5℃/min,resulting in a seven-step MgSO_(4)·7H_(2)O dehydration process with a dehydration heat close to the theoretical value.The reaction kinetic analysis indicated that the rate of hydration was approximately 50%lower than that of dehydration.In addition,thermal cycling tests of MgSO_(4)·7H_(2)O under the conditions of this study(small sample size)indicated good cyclability,with hydration rates increasing with increasing cycling numbers up to approximately 10 cycles where level-off occurs.These results are consistent with scanning electron microscopy analyses,which revealed the formation of cracks and channels in the salt hydrate particles,facilitating mass transfer and improved kinetics.

关 键 词：thermochemical energy storage thermal analysis thermal cycling MgSO_(4)hydration/dehydration kinetics 

分 类 号：TK02[动力工程及工程热物理]