Thermoelectric generators: A case study in multi-scale thermal engineering design

Abstract In this chapter we review the fundamental principles of thermoelectric phenomena, devices, and optimization techniques, with a focus on the multi-scale design of thermoelectric energy generators (TEGs). TEG technology represents a fascinating case study of the interplay between thermal and electrical transport, with pronounced multi-scale impacts from nanoscale phonon and electron transport to the design of efficient heat exchangers in the optimization of a complete system. We explore several of these areas in detail, with particular attention given to the effects of temperature-dependent thermoelectric material properties on the optimal ratio of hot-to-cold side heat exchanger thermal resistances and the relation to the second law of thermodynamics in the macroscale system design. These conclusions are then connected to theory behind the design of thermoelectric materials through nanoengineering. Finally, we explore cost considerations related to TEG system heat exchanger design, offering a new perspective in the approach to the technoeconomic optimization of TEG power systems.