Combustion and Power Generation Characteristics of a Thermoelectric Generator Fueled by Hydrogen-Enriched Compressed Natural Gas (HCNG)

Hydrogen-enriched compressed natural gas (HCNG) is a promising transitional fuel for residential-scale distributed power, yet its impacts on direct-combustion thermoelectric generator (TEG) systems remain insufficiently quantified. In this study, a micro-scale TEG integrated with a commercially available self-aspirating household burner was experimentally investigated under thermal inputs of 700–2500 W and hydrogen blending ratios of 0–20 vol%, using open-loop water cooling to maximize heat rejection. The hot- and cold-side temperatures exhibited negligible variation with a hydrogen addition, and the maximum electrical output was essentially preserved across all blending ratios; at 2500 W the system delivered 75.8 W with a system efficiency of 3.03%. In contrast, hydrogen blending substantially reduced pollutant emissions: at 2500 W, CO decreased from 52.7 to 1 mg/m3 and CO2 from 6.73% to 5.36% as the hydrogen fraction increased from 0 to 20 vol%. Meanwhile, combustion stability improved, indicated by a reduced coefficient of variation (0.77% → 0.49%). These results demonstrate that up to 20 vol% hydrogen blending can achieve significant emissions mitigation without compromising TEG power performance, supporting HCNG-fueled TEGs as a practical option for residential backup power.