Thermoelectric power generations from vehicle exhaust gas with TiO2 nanofluid cooling

Vehicle engine efficiency is considered low by approximately 30% only. More than half of the fuel energy from the engine is lost in exhaust piping and dissipated through cooling systems. One alternative approach to increase engine efficiency is by utilizing the waste heat recovery system that emphasizes on the conversion from heat to electrical energy. This is possible with the use of a thermoelectric generator (TEG). The challenges of using a TEG in the heat exchanger application is due to its low thermal conversion efficiency and low power output. To increase the efficiency of TEG, the nanofluid cooling, specifically titanium oxide (TiO2), was introduced into the system. Nanofluids have been tested in the past in many heat exchanger applications and have shown heat transfer improvements. This study had conducted testing using a TEG set-up that connected to a vehicle exhaust system. The TiO2-water nanofluid functioned as a cooling medium to remove the heat from the TEG cold surface. Engine speed in idling conditions varied during the testing between 700 and 1500 RPMs. This project aimed to investigate and conduct an experiment on TEG power generation using waste heat from vehicle exhaust gas with TiO2-water cooling. The experiment objective was to assess the effectiveness of TiO2-water nanofluids cooling, and its effect on the TEG power output and efficiency. TiO2 has positively enhanced TEG thermal conversion and electrical power output when compared to water cooling, through various engine speeds.