Heat transfer enhancement of phase change material (PCM) during the charging (melting) process is crucial in thermal energy storage (TES) systems. This study presents the enthalpy-based lattice Boltzmann method (LBM) simulation of ice melting enhanced through dispersion of Cu-nanoparticles in annuli. A double distribution function (DDF) model is used to solve the convection–diffusion equation including nonlinear convection and isotropic diffusion terms. The simulations are carried out under the following conditions: Pr=6.2,Ste=1,Ra=2×105. The effects of nanoparticles volume fraction and the position of the hot cylinder on the temperature contour, streamline and full melting time are illustrated.