The increasing demand for efficient energy utilization has intensified research on thermal energy storage (TES) systems, where heat exchangers play a critical role in enhancing heat transfer performance. This study presents the assembly and testing of a lab-scale heat exchanger designed for thermal energy storage applications. The objective was to develop a compact, cost-effective experimental setup capable of evaluating thermal performance under controlled operating conditions. The heat exchanger was assembled using readily available materials and configured to facilitate efficient heat transfer between the heat transfer fluid and the storage medium. Instrumentation, including thermocouples and flow measurement devices, was integrated to monitor inlet and outlet temperatures, flow rates, and overall heat transfer characteristics. Experimental testing was conducted under varying flow rates and temperature conditions to assess thermal efficiency, heat transfer rate, and system stability. Results demonstrate that the assembled system effectively stores and releases thermal energy, with performance strongly influenced by flow rate and temperature gradient. The experimental findings validate the suitability of the lab-scale setup for studying heat exchanger behavior in TES systems and provide a foundation for further optimization and scaling. This work contributes to the development of efficient, small-scale thermal energy storage solutions for renewable energy and waste heat recovery applications.