Ma Binjian, Shin Donghyun, Banerjee Debjyoti
School of Mechanical Engineering and Automation, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
School of Engineering & Technology, Central Michigan University, Mount Pleasant, MI 48859, USA.
Nanomaterials (Basel). 2020 Nov 16;10(11):2266. doi: 10.3390/nano10112266.
Molten salts mixed with nanoparticles have been shown as a promising candidate as the thermal energy storage (TES) material in concentrated solar power (CSP) plants. However, the conventional method used to prepare molten salt nanofluid suffers from a high material cost, intensive energy use, and laborious process. In this study, solar salt-AlO nanofluids at three different concentrations are prepared by a one-step method in which the oxide nanoparticles are generated in the salt melt directly from precursors. The morphologies of the obtained nanomaterials are examined under scanning electron microscopy and the specific heat capacities are measured using the temperature history (T-history) method. A non-linear enhancement in the specific heat capacity of molten salt nanofluid is observed from the thermal characterization at a nanoparticle mass concentration of 0.5%, 1.0%, and 1.5%. In particular, a maximum enhancement of 38.7% in specific heat is found for the nanofluid sample prepared with a target nanoparticle mass fraction of 1.0%. Such an enhancement trend is attributed to the formation of secondary nanostructure between the alumina nanoparticles in the molten salt matrix following a locally-dispersed-parcel pattern. These findings provide new insights to understanding the enhanced energy storage capacity of molten salt nanofluids.
混合纳米颗粒的熔盐已被证明是一种很有前景的聚光太阳能发电（CSP）厂热能存储（TES）材料。然而，用于制备熔盐纳米流体的传统方法存在材料成本高、能源消耗大以及工艺繁琐等问题。在本研究中，通过一步法制备了三种不同浓度的太阳能盐-AlO纳米流体，该方法是在前体盐熔体中直接生成氧化物纳米颗粒。通过扫描电子显微镜观察所得纳米材料的形态，并使用温度历史（T-history）方法测量比热容。在纳米颗粒质量浓度为0.5%、1.0%和1.5%时，从热表征中观察到熔盐纳米流体的比热容有非线性增强。特别是，对于目标纳米颗粒质量分数为1.0%制备的纳米流体样品，发现比热容最大增强了38.7%。这种增强趋势归因于熔盐基质中氧化铝纳米颗粒之间按照局部分散包裹模式形成了二级纳米结构。这些发现为理解熔盐纳米流体增强的储能能力提供了新的见解。
