Economic and Environmental Analysis of Thermoelectric Waste Heat Recovery in Conventional Vehicles Operated in Korea: A Model Study

Thermoelectric (TE) waste heat recovery from automotive exhaust streams is a potential technology that can significantly increase the overall efficiency of vehicles and subsequently reduce the consumption of fossil fuels. By reducing the consumption of fossil fuels, vehicular application of TE generators may also potentially reduce the emission of greenhouse gases (GHGs) and other air pollutants from the transportation sector. In this study, we analyse the economic benefit and feasibility of TE waste heat recovery systems in conventional vehicles operated in Korea by analytically modeling related vehicle systems and by analyzing driving patterns in urban environments. The economic effects of the associated efficiency improvement and the reduction of GHGs and air pollutants are simultaneously considered. Vehicular application of a TE generator may reduce 0.15 kL/year for a mid-size sedan and 1.04 kL/year for a medium-duty truck through fuel savings at a typical driving speed of 80 km/h. Based on the benefit–cost ratio analysis, it is shown that the economically acceptable costs of TE waste heat recovery systems are 744 $/kW for the mid-size sedan and 2905 $/kW for the medium-duty truck, respectively, when an operation period of 10 years is assumed. In terms of GHGs and air pollutants, the reduction annually amounts to 0.334 tCO₂e of GHGs, 0.142 kg of CO, 0.00290 kg of VOC, 0.0150 kg of NO_X, 0.198 kg of NH₃, and 0.00006 kg of SO_X for the mid-size sedan, while 2.65 tCO₂e of GHGs, 1.974 kg of CO, 0.401 kg of VOC, 6.98 kg of NO_X, 0.00034 kg of NH₃, and 0.00229 kg of SO_X can be annually reduced by applying a TE generator in the medium-duty truck.