Saving energy or converting it to different forms requires a continuous technique to improve the applications’ thermal performance. The present investigation analyzed the thermal performance and temperature distribution of the Phase Change Material (PCM) discharging method numerically and experimentally inside an annulus of concentric tube. The inlet temperature of heat transfer fluid flow in the inner tube of the annulus was maintained to be lower than the solidification points of the PCM. The computational domain has been simulated as a 3D model for the coupled system. Under various flow rates, the local temperature is measured and computed. It is found that the computational predictions in a good matching with the acquired experimental data. Different mass flow rates have been considered varying in range of (0.0134-0.0952) kg/s. The experimental results showed that there is an inverse proportional relationship between the amount of mass flow rates and the time required for the solidification of paraffin wax. The optimum times (275, 220, 165, and 75) minutes are reached to obtain hot water for domestic use compared to the previously mentioned mass flow rates during the discharge process.