The study analyzed numerically and experimentally the thermal performance and temperature evolution during the period of melting case of a Phase Change Material PCM inside an annular space of concentric pipes. The inlet temperature of the working fluid, water, that flows to the inner pipe of the annulus was maintained at almost a constant temperature of 333 K higher than the melting point of the PCM. The mathematical model for the current 3D coupled system was solved numerically by ANSYS FLUENT 2021 R1. The temperature at different positions in the system was measured under different mass flow rates. The preliminary results indicated that there is a very good matching and agreement between the computational and the experimental findings relating to the temperature measurements. Different mass flow rate cases are considered in the experiments ranging from 0.0952 kg/s to 0.0134 kg/s. This range of flow rates was utilized in running the experiments to obtain the required data. The results showed that there is a maximum variation, ranging from 3.4% to 4.8%, between the numerical and experimental findings at the maximum mass flow rate. This error is an acceptable limit for comparing the computational and experimental results in the present investigation.