A regenerative concept for thermoelectric power generation

•A regenerative concept for TE based waste heat recovery systems is proposed.•Similar power output to high-T TEGs is achieved using only low-T TE materials.•Low-cost, reliable, and available low-T TEMs can be used for high-T applications. This paper presents a regenerative concept for thermoelectric (TE) based waste heat recovery systems called thermoelectric generators (TEGs). TEG is usually a modified heat exchanger with the addition of thermoelectric modules (TEMs) to recover waste heat for power generation. To utilize heat from high temperature heat sources, current researches have largely been focused on the development of high temperature TE materials. In this study, we describe a regeneration concept in which a precooler is used to lower the temperature of the hot gas and at the same time regenerate hot air from the cold air supply for Bi2Te3-based TEGs, avoiding the use of high-temperature thermoelectric materials. It is found that the regenerative TEGs can achieve a similar power output compared with TEGs using high temperature TE materials such as filled-skutterudites (combined filled skutterudites and Bi2Te3 TE materials) through obtaining a higher heat scavenging rate. Thus, the regenerative TEGs also have a similar absolute efficiency, defined according to the total available enthalpy from the hot gas. This could represent a paradigm shift in the TEG research and development, that much lower-cost, reliable, and readily available TE materials and modules can be used for high temperature applications, and will ultimately enable wide spread deployment of TEGs for real world waste heat recovery applications.