A Numerical Parametric Study of a Double-Pipe LHTES Unit with PCM Encapsulated in the Annular Space

Evdoxia Paroutoglou, Peter Fojan, Leonid Gurevich, Simon Furbo, Jianhua Fan, Marc Medrano, Alireza Afshari

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Latent heat thermal energy storage (LHTES) with Phase Change Materials (PCM) represents an interesting option for Thermal Energy Storage (TES) applications in a wide temperature range.
A tubular encapsulation model of an LHTES with PCM was developed, and the calculated data were analyzed. In addition, a parametric analysis for the preferable system geometry is presented. Organic paraffin RT18 with a melting point of 18 ◦C was utilized as PCM for different geometries of LHTES,
and the addition of internal and external fins and their influence on LHTES thermal conductivity was investigated. One-step heat exchange from outdoor air to PCM and from PCM to water characterizes the LHTES system in solidification and melting processes, respectively. A 2D axisymmetric model
was developed using Comsol Multiphysics 6.0. The LHTES unit performance with PCM organic paraffin RT18 encapsulated in electrospun fiber matrices was analyzed. The study results show that longer internal fins shorten the melting and solidification time. The phase change process was accelerated by 31.12% in the charging compared to the case with no fins of the same external tube
diameter. Direct contact of PCM electrospun fiber matrix with 23 ◦C water showed instant melting, and the phase change process was accelerated by 99.97% in the discharging cycle.
Original languageEnglish
Article number13317
Issue number20
Number of pages16
Publication statusPublished - 17 Oct 2022


  • Comsol Multiphysics
  • PCM
  • numerical simulation

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