This thesis developed in collaboration with Leonardo Innovation Hub focuses on the preliminary design of an advanced Thermal Management System (TMS) for High-Power Pulsed Load (HPPL) applications. The growing demand for HPPL systems in industrial and defence applications has led to an increase in power density and associated thermal loads, transforming thermal management from a secondary consideration into a fundamental design constraint. In pulsed power operation, rapid energy dissipation results in significant heating of electrical components, making precise thermal regulation crucial for ensuring system reliability and optimal performance. To address the significant limitations of traditional cooling architectures, particularly as power densities continue to rise and stringent demands for compactness, scalability, and efficiency become more critical, this work introduces the development of a novel preliminary Thermal Management System tailored specifically for a high-performance power processing system.