Microencapsulated Phase Change Materials in Solar-Thermal Conversion Systems: Understanding Geometry-Dependent Heating Efficiency and System Reliability

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• 作者：Zhaoliang Zheng ; Zhuo Chang ; Guang-Kui Xu ; Fiona McBride ; Alexandra Ho ; Zhuola Zhuola ; Marios Michailidis ; Wei LiRasmita Raval ; Riaz Akhtar ; Dmitry Shchukin
• 刊名：ACS Nano
• 出版年：2017
• 出版时间：January 24, 2017
• 年：2017
• 卷：11
• 期：1
• 页码：721-729
• 全文大小：598K
• ISSN：1936-086X

文摘

The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency and reliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the h-MPCMs is enriched with nanocarbons and has a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems.