Abstract
This study investigated the comparative analysis of the performance and efficiency of heat transfer in parallel flow and counter flow double tube heat exchangers. The research adopted a laboratory-based experimental design in which a concentric tube heat exchanger was operated under controlled conditions to evaluate the influence of flow configuration on thermal performance. Hot and cold water were used as working fluids, and key parameters such as inlet and outlet temperatures, heat transfer rate, log mean temperature difference, overall heat transfer coefficient, and thermal effectiveness were determined for both configurations. The results revealed that the counter flow arrangement consistently exhibited superior thermal performance compared to the parallel flow configuration. This improvement was attributed to the sustained temperature gradient along the length of the heat exchanger, which enhanced heat transfer efficiency and effectiveness. In contrast, the parallel flow configuration showed a rapid reduction in temperature difference, leading to lower heat transfer performance. The findings of the study are consistent with established heat transfer theories and previous empirical studies. Overall, the study concludes that counter flow double tube heat exchangers provide better energy utilization and are more suitable for applications requiring high thermal efficiency.