Investigation and Improvement of Performances of a Two-Stage Thermoelectric Generator

About 60–70% of fuel energy is wasted in automobile exhaust, and thus, to recover the heat from the exhaust gas, a theoretical model of a two-stage thermoelectric generator is developed in this paper. Sixteen thermoelectric modules were installed on the upper and lower sides of a rectangular exhaust gas channel. A water-cooling system is employed to absorb the liberated heat by TEG. The performance parameters of the thermoelectric generator were investigated at various hot gas temperatures, hot gas flow rates, water temperature, and water flow rate. The two-stage thermoelectric generator produces 24.41% more power and 22.26% more efficiency than a single-stage system. The system can generate a maximum power of 188.34 W with a corresponding conversion efficiency of 12.17%. When the exhaust flow rate increased from 10 g/s to 40 g/s, the maximum power and efficiency were increased by 42.57% and 14.12%, respectively.