title: Microencapsulated Phase Change Materials in Solar-Thermal Conversion Systems: Understanding Geometry-Dependent Heating Efficiency and System Reliability.
abstract: 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.
authors.affiliation: Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
authors.forename: Zhaoliang
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Centre for Materials and Structures, School of Engineering, University of Liverpool , Liverpool L69 3GH, United Kingdom.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Chang
authors.affiliation: International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University , Xi'an 710049, China.
authors.forename: Guang-Kui
authors.initials: GK
authors.lastname: Xu
authors.affiliation: Surface Science Research Centre, University of Liverpool , Liverpool L69 3BX, United Kingdom.
authors.forename: Fiona
authors.initials: F
authors.lastname: McBride
authors.affiliation: Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ho
authors.affiliation: Centre for Materials and Structures, School of Engineering, University of Liverpool , Liverpool L69 3GH, United Kingdom.
authors.forename: Zhuola
authors.initials: Z
authors.lastname: Zhuola
authors.affiliation: Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
authors.forename: Marios
authors.initials: M
authors.lastname: Michailidis
authors.affiliation: Chemical Engineering & Applied Chemistry, European Bioenergy Research Institute and Aston Materials Centre, Aston University , Birmingham B4 7ET, United Kingdom.
authors.forename: Wei
authors.identifier: 0000-0003-4036-467X
authors.initials: W
authors.lastname: Li
authors.affiliation: Surface Science Research Centre, University of Liverpool , Liverpool L69 3BX, United Kingdom.
authors.forename: Rasmita
authors.initials: R
authors.lastname: Raval
authors.affiliation: Centre for Materials and Structures, School of Engineering, University of Liverpool , Liverpool L69 3GH, United Kingdom.
authors.forename: Riaz
authors.initials: R
authors.lastname: Akhtar
authors.affiliation: Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
authors.forename: Dmitry
authors.identifier: 0000-0002-2936-804X
authors.initials: D
authors.lastname: Shchukin
keywords: PF-QNM; emulsification; encapsulation ratio; microencapsulation; nanocarbons; phase change materials; solar-thermal conversion