Optimization of vapor anode multi-tube alkali metal thermoelectric converter based on an integrated model

The alkali metal thermal to electric converter (AMTEC) is a promising technology for direct conversion of heat to electricity. Design optimization and cell fabrication have been attracting wide interest to improve the cell performance. An integrated analysis model has been developed in this paper. The model includes three coupled parts of a thermal model, an electric model, and a pressure loss model, which are solved by numerical iteration method. All radiation view factors in the cell are calculated by the thermal radiation analysis software RadCAD based on Monte-Carlo ray-tracing technique to accurately and stably simulate the heat flux between the radiation surfaces to support design optimization. The integrated analysis model's predictions are in good agreement with experimental results of PX-3A cell for a wide range of external loads, which confirms the accuracy of the integrated analysis model and the rationality of the solution processes. After model validation, the effects of various parameters on the cell performance are investigated, including the cold end temperature, geometry of the heat shield, number of BASE tubes, heat loss through the cell wall, and electrode material. The optimization suggestion and optimal parameter range are given in the analyses. At last, an integrative optimization is performed using achievable parameters under current technology. The peak power and conversion efficiency have been improved from 4 W to 6.7 W and 13.5% to 18.1%, respectively.