The right method for overcoming the lack of conventional SWH is to use the Latent Heat Storage (LHS) method as Thermal Energy Storage (TES). Phase Change Material (PCM) has a high energy density but low thermal conductivity. Provision of copper powder on PCM can increase its thermal conductivity. In this study the PCM used was a mixture of paraffin wax with copper 10% mass fraction. However, the experimental TES research is expensive, therefore a Computational Fluid Dynamics (CFD) simulation study is needed. One of the objectives of this research is to determine the time of the melting and freezing of the paraffin wax mixture with copper 10% fraction mass. The geometry configuration consists of a tank as a Heat Transfer Fluid (HTF) and 32 copper pipes containing a PCM-Cu. This simulation is carried out using ANSYS Fluent 18.0 which consists of a charging and discharging discontinue. In the charging process has a water discharge of 0.9 LPM and a variation of heat flux 900 W and 1100 W. While the discharging discontinue with LPM and 2.5 LPM. Simulation objects include temperature evolution and melting and solidification of the PCM-Cu. The simulation results show that the greater the value of the heat flux, the faster the melting time and the greater the flowrate, the faster the solidification time. This is evidenced by the melting time in the 900 W charging process that is 4.2 hours and 1100 W which is 2.94 hours. While the time of solidification in the process of discharging discontinue in a variation of 1.5 LPM is 0.76 hours and 2.5 LPM is 0.5875 hours.