Progress in the design and development of thermoelectric generator heat recovery systems: A comprehensive review

The global energy transition emphasizes emission reduction, energy efficiency, and renewable integration. However, according to the second law of thermodynamics, all energy conversion systems inherently lose a portion of input energy as waste heat, representing a vast, underutilized resource for sustainable power generation and efficiency enhancement. Earlier studies focused solely on material-specific advancements or single-source applications. This study provides a comprehensive and integrative assessment of thermoelectric generator (TEG) heat recovery systems, encompassing artificial intelligence (AI) and machine learning (ML)-assisted materials design, techno-economic analysis, multi-physics modeling, dynamic system performance under different feasible heat sources, critical challenges and future approaches. The review begins with an in-depth assessment of diverse waste heat sources, including solar ponds, photovoltaic cells, cookstoves, biomass gasifiers, automotive engines, and industrial processes. It highlights suitable semiconductor materials across broad temperature ranges and systematically discusses recent advancements in TEG systems design, optimization, and performance enhancement for efficient waste heat recovery. The performance of TEGs highlights that Bi2Te3-based compounds remain ideal for low temperature heat sources while PbTe, skutterudites, and Mg3Sb2 alloys perform efficiently with mid-temperature sources. Integration of AI/ML, and multiphysics simulation has accelerated design optimization, improved prediction accuracy, and reduced computational cost. Hybrid configurations of TEGs with photovoltaic cells, biomass-driven systems, and automotive engines demonstrate strong potential in improving fuel efficiency, reducing emissions, and enhancing energy utilization. Despite the inherent advantages, commercialization remains limited by material costs and moderate conversion efficiencies. Therefore, future research needs to focus on scalable manufacturing, recyclable and non-toxic materials, and hybrid system integration. Aligning with circular economy principles, next-generation TEG systems will contribute significantly to global decarbonization and sustainable energy transitions. This review offers a unified roadmap connecting scientific, engineering, and economic insights toward real-life deployment of efficient, durable, and eco-friendly TEG technologies.