Exergy Analyses on Thermoelectric Generators

Abstract

The second-law analysis or the exergy analysis on a thermoelectric generator (TEG) was made to explore actual power producing ability of the device. The TEG is a device that converts heat directly to electricity. This property is fascinating in recent worldwide circumstance of energy saving and is widely applicable to many situations existing temperature difference in our surroundings. However, its energy efficiency or electricity conversion efficiency is usually less than one percent presently: energy efficiency has been thought to be too low to use power production even though the cost problem would not be considered. In this study, exergy balance analysis disclosed that the TEG has almost equivalent exergy efficiency to the solar photovoltaic cell and the value increases with increase of lower working temperature despite the energy efficiency keeps almost constant. From this analysis, it could be concluded that the TEG is useful for heat sources that have small temperature difference with a large amount of capacities such as ocean thermal energy, waste heat in a city, etc., and is also available to the topping power generators for high temperature heat sources.