This study presents a numerical investigation of the charging behavior of a vertical packed-bed latent heat thermal energy storage unit filled with spherical paraffin capsules. The capsule bed is modeled as a porous medium, and a local thermal non-equilibrium formulation is adopted to solve separate temperature fields for the water and PCM phases. The model includes porous flow resistance, interphase heat transfer, apparent heat capacity based on phase change, and heat loss from the insulated wall. The results indicate that the PCM temperature increases from about 54–55^∘ "C" at 200 min to the melting range near 60^∘ "C" at approximately 250 min. A clear latent-heat plateau is observed from about 250 to 490 min, after which the PCM temperature rises sharply, reaching approximately 66–68 ⸰C. The water temperature remains higher than the PCM temperature during melting and exceeds 64 ⸰C, confirming local thermal non-equilibrium. Phase-field contours show progressive melting from 300 to 900 min, with near-complete melting at 900 min. Flow-rate cases of 1.5, 2.5, 3.5, and 4.5 L/min demonstrate that the charging response depends strongly on the balance between convective transport and fluid residence time. The manuscript explicitly evaluates HTF temperature, PCM temperature, liquid fraction, pressure loss, and charging time as key model outputs.