Numerical analysis of mechanical reliability of multi-coated phase change materials

Josep Forner-Escrig,Roberto Palma,Leonor Hernández,David Valdesueiro,Aristeidis Goulas,J Ruud Van Ommen,Damiano La Zara,Nuria Navarrete,Rosa Mondragón

doi:10.1051/e3sconf/202132102019

Josep Forner-Escrig, Roberto Palma + Show 7 more

Open Access

https://doi.org/10.1051/e3sconf/202132102019

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Abstract

Nanoencapsulated phase change materials (nePCMs) are nowadays under research for thermal energy storage purposes. NePCMs are composed of a phase change core surrounded by a shell that confines the core when molten. One of the main concerns of nePCMs when subjected to thermal processes is the mechanical failure of the passivation shell initially present in commercial metallic nanoparticles. In order to overcome this issue, multi-coated nePCMs, based on the synthesis of an additional coating by atomic layer deposition, appear to be as a candidate solution. With the objective of studying the influence of the composition and thickness of the additional nePCM shells on their probability of failure, a numerical tool combining a thermomechanical finite element model with phase change and Monte Carlo algorithms is developed. This tool also allows including the uncertainty of material and geometrical properties into the numerical analysis to account for their influence in the mechanical performance of nePCMs. In the present work, the mechanical reliability of SiO2 and Al2O3 coatings on Sn@SnOx nanoparticles is assessed by considering both deterministic and probabilistic failure criteria and Al2O3 coatings appear to have a better mechanical performance than their SiO2 counterparts.

Highlights

Energy generation and conversion is one of the major concerns that society is facing nowadays
Numerical studies performed by considering deterministic failure criteria show the need to consider probabilistic ones because by using a deterministic critetion slightly underestimates the Probability of Failure (POF) of nanoencapsulated phase change materials (nePCMs) shells, which may result in a remarkable loss of energy storage capability of nanofluids
This work presents a numerical tool combining a thermomechanical FE model with Monte Carlo (MC) techniques, which is used to assess the mechanical reliability of different nePCMs

Summary

Introduction

Energy generation and conversion is one of the major concerns that society is facing nowadays. In some previous works [6], it was found that the shell thickness as well as other material parameters such as the melting temperature or the thermal expansion coefficient of the core were some of the variables having more influence on the mechanical failure of nePCM shells. In order to systematically assess the mechanical performance of different nePCMs, to incorporate the measurement dispersion of material and geometrical parameters into the numerical analysis and to gain deeper insight into the causes of the failure of nePCMs, a numerical tool combining a thermomechanical finite element model with phase change with Monte Carlo (MC) simulations is presented in this work. The performance of the following nePCMs (core@inner_shell@outer_shell) experimentally synthesised by ALD is assessed: Sn@SnO, Sn@SnO2@SiO2 and Sn@SnO@Al2O3

Analysis and modelling

Results and discussion

Conclusions