The latent heat energy storage using Phase Change Material (PCM) has an enormous appeal due to its profitable points associated with density and thermal characteristics. In this regard, a heat exchanger is modelled and analyzed to visualize the thermal behaviour and melting progression of PCM in a circular-shaped enclosed erect vessel via CFD tool. This work analyzes a multiphase transient study of a U-shaped copper tube placed in a closed cylindrical vessel through which heat transfer fluid flows for transferring heat to the PCM. This work shall be advantageous to the researchers to realize the thermal performance, time of PCM melting etc., to carry out research related to solar heat storage. The present study reports substantial decrease in the time taken to melt all the PCM filled in the container. Almost 32% of time is saved in the process of melting of PCM and thus improving the efficiency of the energy storage system.