Computational and Experimental Evaluation of Thermoelectric Generator for Waste Heat Recovery in Internal Combustion Engine Applications

Much of the thermal energy derived from combustion of fuel is lost through exhaust gases. By effectively recovering waste heat energy in the form of electricity, it can be used to recharge batteries or power auxiliary systems thus improving both performance and fuel economy. In this work, the use of thermoelectric generators (TEG) for energy recovery were studied using both computational and experimental strategies. The efficiency of TEG (Ƞ_TEG) was analyzed through computational methods by changing temperature gradients, Seebeck coefficient (α), and dimensions of the P- and N-type plates individually. The results of computational analysis showed that in comparison to vertical and planar configuration, mixed-type thermocouple delivered 83.3% and 96% more power, respectively. Raising the α, enhanced the Ƞ_TEG by 57% and lowering α affected the Ƞ_TEG by 9.5% for mixed thermocouples. A marginal development in the Ƞ_TEG was achieved by increasing the length of the P- and N-type semiconductors but decreasing the length improved Ƞ_TEG by more than 95%. In the experimental approach, the Ƞ_TEG of a Peltier module-based TEG was studied under static and dynamic testing conditions on a motorcycle by connecting more than one module in series and parallel, respectively. The average power generated over a range of engine speeds was 10.9 W and 10.6 W for series and parallel configurations, respectively, under static test conditions. The average power obtained with dynamic tests was 10.5 W and 12.2 W for series and parallel configurations, respectively.