Heat exchangers play a crucial role in modern thermal systems by enabling efficient heat transfer between fluids at different temperatures. Their performance significantly influences energy efficiency in industries such as power generation, chemical processing, refrigeration, and HVAC systems. The design parameters of heat exchangers—including geometry, flow configuration, baffle design, tube arrangement, and surface enhancement— strongly affect temperature distribution and heat transfer rate. This review paper investigates the influence of heat exchanger design on thermal performance and highlights recent developments in optimization techniques and predictive modeling. Particular emphasis is placed on shell-and-tube heat exchangers due to their widespread industrial application. The review also discusses modern design improvements such as helical baffles, computational fluid dynamics (CFD) analysis, and artificial intelligencebased prediction models. Studies by Prasad and Sinha (2023a; 2023b) demonstrate the potential of optimization algorithms and neural networks in enhancing heat transfer while reducing pressure drop. Through a systematic review of previous studies, this paper identifies the key factors affecting heat exchanger performance and outlines future research directions for improving thermal efficiency and energy sustainability.