Fast waste heat recovery in 100–150 °C using close-contact charging of nano-enhanced PCM composite

For fast waste heat recovery in 100–150 °C the unconstrained melting of phase change material (PCM) composite is investigated. The composite is based on Erythritol PCM with 2.5% volume fraction of copper nano-additive. This PCM composite is referred as nano-enhanced phase change material (NEPCM). Th...

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Bibliographic Details
Published in:Journal of molecular liquids 2019-07, Vol.285, p.347-361
Main Authors: Soni, Vikram, Kumar, Arvind, Jain, V.K.
Format: Article
Language:English
Subjects:
Close-contact melting
Energy storage
Erythritol
Nano-enhanced PCM
Solid sinking
Thermal performance
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Summary:For fast waste heat recovery in 100–150 °C the unconstrained melting of phase change material (PCM) composite is investigated. The composite is based on Erythritol PCM with 2.5% volume fraction of copper nano-additive. This PCM composite is referred as nano-enhanced phase change material (NEPCM). The unconstrained melting in presence of nano-additives is modelled by developing a novel continuum model that accounts for phase change, bulk solid sinking and close-contact melting. By using a modified form of conservative energy equation different solid and liquid phase thermal properties are employed in the model. The predicted sinking pattern of the bulk solid compares well with the benchmark experimental result on n-octadecane PCM. The thermal field because of solid sinking is analyzed, and a high melting rate at reservoir bottom is observed due to close-contact melting. The energy behavior is analyzed in detail by presenting a comparison of global and local thermal and flow fields, and melt fraction distribution in PCM and NEPCM. For the melting process, the effect of the operational parameter is found to be more deterministic than the geometrical parameter. Overall, NEPCM melting completes earlier than PCM melting, however, there is a trade-off between the charging rate and the storage capacity for the NEPCM. System's performance is analyzed with the help of thermal performance parameters. •Erythritol-Copper based NEPCM for fast waste heat recovery•Phase change model with bulk solid sinking, close-contact melting and nano-additive•Energy equation considers different solid and liquid phase thermal properties.•Thermal field, flow field and energy density analysis at local and global scale•Trade-off between of charging rate and storage capacity for NEPCM
ISSN:0167-7322
1873-3166
DOI:10.1016/j.molliq.2019.03.132