Modeling and Simulation of a Helical-Finned Tube Integrated with Paraffin Wax in a Solar Water Heater System for Enhanced Thermal Energy Storage Performance is a research study authored by Mansour F. Yassen, Kadhim Hussein Suffer, Malek Khalaf Albezuirat, and Mohammed Alhagyan. The study investigates the enhancement of flat-plate solar water heater performance through the integration of paraffin wax as a phase change material (PCM) with helical half-fins surrounding the absorber tube. A Computational Fluid Dynamics (CFD) model based on the Finite Volume Method (FVM) was employed to simulate the melting process and analyze heat transfer characteristics. The numerical results demonstrated that the helical-fin configuration increased the average liquid fraction by 9.33% compared with the conventional PCM design, leading to faster melting and improved thermal energy storage. Furthermore, the enhanced system maintained a higher outlet water temperature during nighttime, confirming its superior thermal storage capability. The findings highlight the effectiveness of combining PCM and helical fins to improve heat transfer and the overall efficiency of solar water heating systems.