Abstract
<jats:sec> <jats:title>Purpose</jats:title> <jats:p>The purpose of this study is to improve the numerical simulation of thermal energy storage systems based on phase change materials (TES–PCM). These systems involve strong nonlinearities due to phase change and natural convection, which makes their design challenging. This study focuses on enhancing computational efficiency and accuracy in modeling the phase transition process through an adaptive mesh strategy within the particle finite element method (PFEM).</jats:p> </jats:sec> <jats:sec> <jats:title>Design/methodology/approach</jats:title> <jats:p>The authors implement PFEM for the simulation of TES–PCM, allowing dynamic remeshing during computation. A new mesh adaptation strategy is proposed to optimize spatial discretization in the mushy zone, based on thermal gradients rather than distance fields. The methodology is validated using experimental data from the literature and verified through a fin-placement optimization problem.</jats:p> </jats:sec> <jats:sec> <jats:title>Findings</jats:title> <jats:p>The proposed method accurately reproduces experimental melting fronts for lauric acid and gallium while reducing computational time by up to 25% compared to classical mesh adaptation. The approach captures the influence of natural convection and fin placement, confirming its robustness and predictive capability for TES–PCM applications.</jats:p> </jats:sec> <jats:sec> <jats:title>Originality/value</jats:title> <jats:p>To the best of the authors’ knowledge, this is the first application of PFEM to TES–PCM problems. The new mesh adaptation criterion enhances efficiency without compromising accuracy, offering a promising alternative to classical fixed-mesh CFD methods. The findings highlight the potential of PFEM as a flexible and efficient tool for simulating phase change problems and guiding the design of TES devices.</jats:p> </jats:sec>