Converting Waste Heat into Usable Electrical Energy Using Thermoelectric Generator

Sadia Islam; S. C. Banik; Minhaz Uddin Midul; Marwa Asgar Tanha

doi:10.38032/scse.2026.4.76

Authors

Sadia Islam Department of Mechanical Engineering, Chittagong University of Engineering & Technology, Chattogram-4349, Bangladesh
S. C. Banik Department of Mechanical Engineering, Chittagong University of Engineering & Technology, Chattogram-4349, Bangladesh
Minhaz Uddin Midul Department of Mechanical Engineering, Chittagong University of Engineering & Technology, Chattogram-4349, Bangladesh
Marwa Asgar Tanha Department of Mechanical Engineering, Chittagong University of Engineering & Technology, Chattogram-4349, Bangladesh

DOI:

https://doi.org/10.38032/scse.2026.4.76

Keywords:

Thermoelectric Generator (TEG), Waste Heat Recovery, Temperature Gradient, Cooling Efficiency, Voltage Output

Abstract

This study explores the performance of thermoelectric generators (TEGs) in converting waste heat into usable electrical energy under different thermal conditions. Three experimental configurations were evaluated: a candle with ice cubes for cooling, a candle with a fan, and car exhaust with ambient air cooling. The candle–ice setup achieved the highest initial voltage output of approximately 2.38 V, attributed to the large temperature difference between the heat source and cooling surface; however, the voltage decreased gradually as the ice melted. The candle–fan setup produced a stable voltage in the range of 1.8–2.0 V, with continuous airflow maintaining a moderate but steady temperature gradient. The car exhaust–ambient air configuration generated the lowest output, between 1.2 and 1.5 V, but required no additional energy for cooling, making it the most practical for real-world applications. The results indicate that while high initial temperature differences yield greater peak voltages, sustaining a consistent gradient is more crucial for continuous power generation. These findings highlight the potential of simple, low-cost TEG systems for small-scale, off-grid, and passive energy recovery applications, such as in vehicles, rural cookstoves, or industrial exhaust systems, offering a clean, silent, and sustainable means of utilizing otherwise wasted heat.

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