DOI: 10.1615/ICHMT.2017.CHT-7
ISBN Print: 9781-56700-4618
ISSN: 2578-5486
THERMOELECTRIC GENERATOR FOR ENERGY RECOVERY FROM THE EXHAUST GASES OF HEAVY-DUTY VEHICLES
RÉSUMÉ
The application of a thermoelectric generator (TEG) to recover energy from the exhaust gases in light and heavy-duty vehicles is addressed using a mathematical model and optimization methods. The TEG is placed downstream of the particle filter of a commercial vehicle of 3.5 tonnes and a heavy-duty vehicle of 40 tonnes. The exhaust is used as heat source and the cooling water as heat sink. Three different heat exchanger fin structures are investigated, namely plain fins, offset strip fins and triangular fins. The analysis is performed for steady state conditions based on typical driving conditions, mass flow rates and temperatures of the exhaust and cooling water. The influence of the fin spacing and fin height on the net and electrical power is studied, as well as the height of the thermocouple legs. Then, an optimization study is performed aiming at the maximization of the net power, for fixed size of the TEG. Two different optimization methods are used, namely a gradientbased search method and a direct search method. The analysis carried out shows that, for typical extra-urban driving conditions, the recovery efficiency is low. The best recovery efficiency found is approximately 2%. Although the ratio of the electrical energy generated by the TEG to the thermal energy of the exhaust gases is still very low, 2% of the 2015 European freight transport wasted energy represents 22 million MJ, which is a significant amount.