Abstract: This paper briefly describes the differences and similarities between solid-state thermoelectric generators and classical Carnot engines at the thermodynamic level. The reasons behind the irreversibility in solid-state thermoelectric conversion are summarized. Enhancing thermoelectric figure of merit can only push the energy conversion efficiency towards the ideal Carnot limit within a certain electric conductivity region. By comparing with the output power of endoreversible Carnot engines, this paper demonstrates the importance of contact thermal resistance and heat exchanging rate to the thermoelectric conversion performance.

Key words: solid-state thermoelectric generator, thermoelectric conversion efficiency, Carnot engine, thermodynamic cycle