Modelling and Experimental Validation of a Thermoelectric Energy Recovery System for Exhaust Heat from Industrial Diesel Generators in Ogun State

Industrial diesel generators in Ogun State, South West Nigeria, reject 25 to 35 percent of fuel energy as exhaust heat, representing a significant recoverable energy resource that is currently wasted. This study develops and experimentally validates a thermoelectric generator module assembly for recovering electrical energy from diesel generator exhaust heat as a supplementary power generation system. A one-dimensional heat transfer model of the thermoelectric energy recovery system is developed, incorporating the temperature-dependent properties of Bi2Te3 thermoelectric modules, an exhaust heat exchanger, and a cold-side liquid cooling loop. Electrical output is optimized through maximum power point tracking control using a DC-DC boost converter. The model is validated against experimental measurements on a test rig integrating 48 Bi2Te3 thermoelectric modules mounted on a custom-fabricated exhaust heat exchanger installed on a 45 kVA Perkins diesel generator at an industrial facility in Sagamu. Experiments are conducted across four generator load conditions from 25 to 100 percent rated load. Model predictions of TEG electrical output agree with experimental measurements within 6.8 percent root-mean-square error across all load conditions. Maximum electrical output of the TEG system was 148 watts at full generator load, corresponding to a heat-to-electricity conversion efficiency of 4.2 percent. Annual energy recovery potential is estimated at 890 kWh for a generator operating 12 hours per day at average 60 percent load. The study analyses the economic viability of the recovery system and identifies material cost reduction targets for commercial competitiveness. Keywords: thermoelectric generator, waste heat recovery, diesel generator, energy efficiency, Ogun State