Effect of Irreversibilities on the Performance of Thermoelectric Generator Investigated Using Exergy Analysis

Abstract

For a practical thermoelectric generator (TEG) system, the performance is affected by many irreversible processes. This study evaluates the effects of multi-irreversibilities on TEG performance using exergy analysis. Based on the exergy analysis, two performance indexes, the energy efficiency and exergy efficiency, are used. A finite element scheme is employed to model the TEG system. The heat loss from the TEG to the environment and temperature-dependent material properties are considered. The results suggest that when the application of the small electrical current is considered, decreasing the hot-reservoir temperature or increasing the cold-reservoir temperature can improve the TEG exergy efficiency. Although heat loss slightly decreases the maximum energy and exergy efficiency, it can improve energy and exergy efficiencies for a case with large electrical current. On the other hand, when the Seebeck coefficient or thermal conductivity is temperature-dependent, both the maximum energy efficiency and exergy efficiency increase with increasing hot-reservoir temperature. However, the temperature-dependence of the electrical resistivity reduces the maximum exergy efficiency when the hot-reservoir temperature increases even though the maximum energy efficiency is increased.