Abstract: Thermoelectric devices can realize the direct conversion of heat and electric energy, and have special advantages in the utilization of waste heat and the development of clean energy technology. But, improving the thermodynamic performance of thermoelectric devices has the more practical significance. In this paper, the thermodynamic characteristics of thermoelectric devices are studied by means of trade-off optimization method (also called Ω criterion). On the basis of constructing a trade-off objective function, the expressions of efficiency and coefficient of performance (COP) under trade-off optimization criterion are obtained, and the influence of thermoelectric figure of merit on efficiency COP is explained in detail. In comparison with the maximum power (maximum cooling power) method, it is found that the thermodynamic performance of thermoelectric devices under the trade-off optimization can easily be improved. 

Key words:  thermoelectric devices, trade-off optimization criteria, efficiency, coefficient of performance