For a packed bed latent heat thermal energy storage system (LHTES), the effects of mass flow rate, inlet temperature, porosity, and geometric orientation of pure silica as a PCM have been computationally studied. The thermal performance of PCM capsules has been investigated using ANSYS FLUENT®. The thermal performance was evaluated using the following metrics: heating capacity (Q_ch), charging rate (p), Thermal Energy Storage (TES) density (q), and TES rate density (w). In this study, the parameters were estimated and compared for three distinct PCM porosities−83.5%, 86.5%, and 88.5%; four different mass flow rates (0.08 kg/s, 0.10 kg/s, 0.12 kg/s, and 0.15 kg/s), four different fluid inlet temperatures (2000 K, 2100 K, 2200 K, 2300 K), and two different geometric orientations (Regular and Staggered). It takes 500s to charge each case. The turbulent flow condition was modeled using the solidification/melting equation. After 500s, higher inlet temperatures, less porosity, and regular orientation result in a larger average melt fraction of PCM. Although the inlet temperature has no impact on the energy transfer efficiency, higher mass flow rates and porosity have a negative impact on it. Both traditional and staggered PCM capsules have almost the same energy transfer efficiency. Heat storage capacity, TES density, charge rate, and rate density increase with mass flow rate. Reduced porosity increased heat storage capacity and charging rate but decreased TES density and rate density. Staggered PCM capsules provide faster charging and heat storage. Decreasing the mass flow rate, input temperature, and porosity increases charging efficiency.