Experimental study of coupled heat transfer and thermoelectric performance in an exhaust waste heat recovery system for a stationary diesel generator

Waste heat recovery from internal combustion engine (ICE) exhaust gases represents an effective approach to improving overall energy utilization and reducing fuel consumption. Among available technologies, thermoelectric generators (TEGs) are attractive due to high reliability and direct conversion of heat into electricity. However, the practical performance of exhaust-mounted TEG systems is largely affected by the coupled heat-transfer processes between the exhaust gas, thermoelectric modules, and cooling system, which remain insufficiently understood under realistic operating conditions. In this study, an exhaust-mounted thermoelectric generator was experimentally developed and evaluated on a stationary diesel engine generator under various operating loads. Two TEG configurations were investigated to evaluate the influence of exhaust thermal conditions on electrical performance. The experimental results show that increasing engine load enhances the exhaust-gas temperature and the temperature difference across the thermoelectric modules, resulting in improved electrical output. The optimized configuration achieved a maximum electrical power of 72 W, while demonstrating stable performance throughout the investigated operating range. The results further indicate that efficient cooling and reduced thermal resistance are essential for maintaining a large temperature gradient and maximizing thermoelectric conversion efficiency. This work provides experimental insight into the heat-transfer characteristics governing exhaust-mounted thermoelectric generators and offers a practical foundation for the thermal design and optimization of waste heat recovery systems for stationary ICEs.