Thermodynamic analysis and optimization of a hybrid power system using thermoradiative device to efficiently recover waste heat from alkaline fuel cell
Xin Zhang, Ehsanur Rahman
Abstract
Low-grade waste heat released from alkaline fuel cells (AFCs) contains enormous useful energy, which can be recycled for energy cascade utilization. However, the traditional heat energy harvesting techniques are limited by low power generation and conversion efficiency. In this work, an alkaline fuel cell/thermoradiative device hybrid system is proposed to address this challenge, where the thermoradiative device (TRD) recycles the waste heat from an AFC, thereby providing additional electrical power. A comprehensive mathematical model of the hybrid system is developed to investigate its general performance characteristics and optimal parameter designs. The hybrid system possesses better output performance than other previously proposed AFC-based hybrid systems, which indicates that the TRD can more efficiently harvest the waste heat produced from AFC than other conventional cogeneration devices. The maximum power density of the hybrid system can be as much as 1.75 times that of the single AFC, and hence, the hybrid system can offer a significant performance boost. Additionally, the optimal operating regime and the critical parameter designs are determined, offering theoretical guidance for improving system performance. The presented work shall pave new routes and provide essential guidelines for designing high-performance waste heat recycling devices.