Experimental and numerical investigation on multi-factors for improving thermal performance and energy efficiency of the H2/CH4 fueled thermoelectric generator

To enhance the energy conversion and efficiency of heat recovery system, a small hydrocarbon-fueled thermoelectric generator (TEG) with optimized modules is proposed. Effects of the operating parameters, heat sink fin geometry and combustion chamber settings, and two-stage TEG design on system performance are discussed and analyzed. Results show that CH4 blending ratio of 20 % and equivalence ratio of 0.9 optimize combustion heat release and energy conversion, yielding higher power output. Increasing mass flow rate boosts power but reduces efficiency due to elevated chemical energy input. Optimal fin dimensions are 14 mm length and 0.5 mm thickness, while a combustion chamber block of 26 mm length and 1.1 mm thickness enhances burner thermal performance. The two-stage TEG system is proposed to address the limitations of the single-stage module. Comparative analysis reveals that the two-stage TEG consistently outperformed the single-stage TEG across all mass flow rates and load resistances, delivering higher power output due to improved utilization of thermal gradients. The two-stage TEG system achieves the maximum power output of 1.16 W when mf = 3.6 × 10−5 kg/s, mCH4 = 20 % and Ф = 0.9. These findings provide valuable insights into the design and optimization of micro thermoelectric systems.