Metal hydrides (MHs) are promising candidates as thermal energy storage (TES) materials for concentrated solar thermal applications. A key requirement for this technology is a high temperature heat transfer fluid (HTF) that can deliver heat to the MHs for storage during the day, and remove heat at night time to produce electricity. In this study, supercritical water was used as a HTF to heat a prototype thermochemical heat storage reactor filled with MgH₂ powder during H₂ sorption, rather than electrical heating of the MH reactor. This is beneficial as the HTF flows through a coil of tubing embedded within the MH bed and is hence in better contact with the MgH₂ powder. This internal heating mode produces a more uniform temperature distribution within the reactor by increasing the heat exchange surface area and reducing the characteristic heat exchange distances. Moreover, supercritical water can be implemented as a heat carrier for the entire thermal energy system within a concentrating solar thermal plant, from the receiver, through the heat storage system, and also within a conventional turbine-driven electric power generation system. Thus, the total system energy efficiency can be improved by minimising HTF heat exchangers.

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用于热能存储应用的金属氢化物反应器的热优化

金属氢化物（MH）有望成为集中太阳能热应用的热能存储（TES）材料。这项技术的关键要求是高温传热流体（HTF），它可以将热量传递给MH，以便在白天进行存储，并在夜间将热量散发出去，以产生电能。在这项研究中，将超临界水用作HTF，以在H ₂吸附过程中加热装有MgH ₂粉末的原型热化学储热反应器，而不是对MH反应器进行电加热。这是有益的，因为HTF流经嵌入MH床内的油管盘管，因此更好地与MgH ₂接触粉末。通过增加热交换表面积并减少特征性热交换距离，这种内部加热模式可在反应器内产生更均匀的温度分布。此外，超临界水可被实现为集中式太阳能热电厂内整个热能系统的热载体，从接收器到储热系统，再到传统的涡轮机驱动的发电系统。因此，可以通过最小化HTF热交换器来提高整个系统的能源效率。