Performance investigation of a system hybridizing high-temperature polymer electrolyte membrane fuel cell with intermediate band thermoradiative device

Abstract

To enhance the efficiency of energy utilization, a novel combined system incorporating a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC), an intermediate band thermoradiative device (IBTRD), and a regenerator is established, where the IBTRD can efficiently exploit the exhaust heat from HT-PEMFC to produce extra power. Based on electrochemistry, semiconductor theory, and the non-equilibrium thermodynamics the mathematical expressions for power density and energy conversion efficiency (ECE) for the integrated device are gained. Meanwhile, considering the multiple irreversible losses, the relationship between the IBTRD voltage and the HT-PEMFC operating current is obtained, and the optimal working regions for key parameters about the presented model are identified. The numerical results demonstrate that the combined model's maximum power density (MPD) and its corresponding energy conversion efficiency are 0.49 W/cm2 and 24.57%, which are respectively 25.61% and 27.52% bigger than those of the single HT-PEMFC. Additionally, it is revealed how vital parameters affect the performance characteristics of the combined model, including the doping level, operating temperature, relative humidity, operating pressure, and the bandgap of IBTRD. The conclusion indicates that an enhancement in MPD from 0.428 W/cm2 to 0.538 W/cm2 and an increase in ECE from 0.224% to 0.255% as the temperature enhances from 423 K to 463 K. The outcomes acquired may be valuable for the design and development of such a true combination system.