###### Abstract  
In response to the growing need for efficient energy conversion technologies, this paper introduces an innovative Tubular Thermoelectric Generator (TTEG), specifically designed for the high-efficiency conversion of waste heat into electrical energy. Unlike conventional flat-plate thermoelectric generators (FTEGs), the TTEG incorporates full-ring thermoelectric elements within a tubular layout, offering a novel approach to thermal energy recovery from fluid-based systems. This design significantly enhances the heat transfer capabilities, thereby improving the efficiency of energy conversion. Moreover, it is optimally tailored for integration into any cylindrical pipe to recapture and repurpose waste heat. Comprehensive simulations and analyses form the core of this study, where the performance of the TTEG is rigorously compared with traditional FTEGs. Under identical conditions of heat exposure, volume, and properties of thermoelectric materials, the TTEG demonstrates a 62.5% increase in output power compared to the TGM1-127-1.0-0.8 thermoelectric module (FTEG). These comparisons highlight the advantages of the tubular design in terms of energy conversion efficiency and practical applicability in various scenarios. The findings reveal that the TTEG not only outperforms its flat-plate counterparts but also presents a scalable and adaptable solution for waste heat recovery in a wide range of industrial and automotive applications. This research contributes to the field of energy science and technology by presenting a detailed experimental setup, complete with reproducible procedures and results. It opens new pathways for the development of more sustainable and efficient energy conversion systems, aligning with the goal of harnessing renewable and sustainable energy sources. The potential applications of this technology in enhancing energy efficiency and reducing environmental impact are vast, making it a significant step forward in the quest for clean and sustainable energy solutions. [PERSON] and [PERSON] [2] observed that, in the industrial sector, over one-third of the energy used in U.S. manufacturing is released into the atmosphere or cooling systems as waste heat. [PERSON] and others [3] have suggested that the bulk chemical industry is the largest energy consumer, followed by the refining and mining industries. Although the utilization rate of waste heat has increased significantly in recent years, a large amount of waste heat is still discharged into the atmosphere. This widespread presence of waste heat in industrial processes underscores the pressing need for innovative solutions to harness this otherwise lost energy. Thermoelectric generators (TEGs) are well-suited for efficient waste heat recovery in limited areas such as aircraft, ships, and vehicles due to their straightforward design, compact size, lightweight, silent operation, longevity, reliability, and minimal maintenance needs [4]. However, the evolution of TEGs has faced challenges such as material optimization, device integration, and durability, necessitating ongoing research and development. The exploration of thermoelectric materials has been diverse, with bismuth telluride being one of the earliest to be widely studied and utilized. Over time, research has branched out to various materials, including but not limited to skutterudites and half-Heuslers. These materials have been recognized for their unique properties that potentially offer enhanced performance and efficiency in various applications, reflecting thermoelectric material research's evolving and multifaceted nature. Most commercially available waste heat recovery devices are designed specifically for flat-plate thermoelectric generators (FTEGs) using flat-plate heat exchangers or square-shaped thermoelectric elements (Figure 1) [5; 6; 7]. From analyzing energy fluxes and heat transfer to system development, research on TEGs is still being actively pursued in various aspects [8; 9; 10].