THE POTENTIAL OF THERMOELECTRIC GENERATOR FOR ENGINE EXHAUST HEAT RECOVERY APPLICATIONS

Abstract

In this study, a thermoelectric generation (TEG) unit was designed and constructed to evaluate the technical potential of exhaust heat recovery system for automobile applications. The TEG system was made up of a commercial thermoelectric module of TEC1 12706 model, an aluminum duct, an aluminum fin heat sink, an electric heater, a cooling fan, AC and DC power supply, an external resistive load and data collection devices. The heater was used as an exhaust heat source simulator to supply heat energy to the hot side of the TEG module. The cooling fan was used for simulating airflow and maintaining uniform heat rejection from the heat sink to the ambient. The experimental investigation had been conducted to characterize the TEG’s performance. The tests were undertaken based on the measurements of temperature at both hot and cold sides of the TEG module, open circuit voltage, and output voltage and current under various external resistive loads. The test results showed that the highest temperature difference was 40.1 oC. This revealed a peak output power of 178.2 mW, a load voltage of 1156.3 mV, a load current of 220 mA and a conversion efficiency of 0.204%. The thermoelectric generation from waste heat energy of a simulated automobile exhaust is technically feasible, though the output power and the conversion efficiency of the TEG unit seem low. In general, it is found that the temperature difference between the hot and cold sides of the thermoelectric module has the most significant impact on the TEG’s performance.