Energy, exergy and ecology performance prediction of a novel SOFC-AMTEC-TEG power system

Abstract

• A novel triple-cycle power system is proposed. • Energy, exergy and ecology performance are analyzed. • Effectiveness and generic performance characteristics are demonstrated. • There is an optimum thermoelectric element number to optimize performance. In order to realize the cascade utilization of the waste heat for the solid oxide fuel cell, a novel triple-cycle system including a solid oxide fuel cell, an alkali metal thermal electric converter and a thermoelectric generator is proposed. In this system, the alkali metal thermal electric converter powered by the waste heat of the solid oxide fuel cell can drive the thermoelectric generator. The proposed system can efficiently generate electricity in a green and noiseless way, and Thomson effect is considered in the thermoelectric generator model. The results show that improving the number of the thermoelectric generator stages is not conducive to the improvement of the system performance. The maximum power density and ecology function density can result in 42.0% and 53.5% improvement over those of the sole solid oxide fuel cell system, respectively. Further sensitivity analysis confirms that there is an optimum element number of the thermoelectric generator to optimize the performance of the triple-cycle system. This work proves the feasibility of the triple-cycle system, and hints the broad prospect of high-grade heat recovery through an alkali metal thermal electric converter-thermoelectric generator unit.