Integrating thermal energy storage (TES) systems with high-temperature heat pumps (HTHPs) combines two highly efficient technologies to develop a robust energy storage and flexible heat supply system. This integration package is predominantly valuable for industrial processes, renewable energy storage and supporting the grid where a consistent and intermittent demand for high-temperature heat (above 300 degrees C) exists. Stirling cycle-based heat pumps offer market readiness for high temperature applications with present capabilities attain above 250 degrees C with ongoing developmental campaigns to further increase the temperature thresholds. To achieve greater productivity in thermal storage processes, higher magnitudes of heat transfer temperature are preferred, wherein the heat transfer fluids such as molten salt (MS) are favoured. Molten salts TES is a mature and effective technology for storing large amounts of thermal energy for the emerging high temperature applications in concentrating solar power plants (CSP). In order to facilitate a sustainable operation of a seamlessly integrated TES and HTHP system, development of robust heat exchangers is key to withstand the high temperatures and maintain an effective heat transfer performance of the system. This study aims at optimizing the design of a Stirling cycle based HTHP integrated compact shell and tube heat exchanger that operates between pressurised helium gas from the HTHP side and a ternary molten salt from the TES side. A two-dimensional computational model is developed in ANSYS Fluent with a triangular tube pattern that enables the flow of pressurised helium gas while MS flows around the shell side. Numerical results are performed based on a geometric design optimization to identify the optimal values that influence the fluid and heat transfer characteristics of MS in a shell and tube heat exchangers with a heating capacity of up to 100 kW. A shell side heat transfer coefficient (hsh) and pressure drop (Delta P) are the key parameters of interest to analyse the heat exchanger characteristics with a primary focus on the shell side flow.