Electrolyte-flow stirling electrochemical energy converter enabling continuous operation

As a novel configuration of electrochemical cycles, electrochemical energy converters (EECs) show great potential in efficient and versatile low-grade heat harvesting. Nevertheless, the complex construction and operation of the existing multi-cell EEC models pose a great challenge to their practical implementation. In this study, a novel electrolyte-flow Stirling EEC model is proposed by employing three stationary electrochemical cells with all-liquid redox couples, in which the complex entire cell motion in multi-cell EEC models is replaced by the circulating electrolytes among three cells. Accordingly, continuous operation is readily achieved with this significantly simplified design and operation. Notably, the cooling power and net power output properties of the electrolyte-flow EEC explicitly demonstrate three energy conversion and transport modes with flexible control to meet dynamic power and cooling loads. Due to the involvement of multiple energy forms, a more comprehensive performance assessment framework accounting for the energy grade difference is innovatively developed by introducing exergy analysis. Moreover, special attention is devoted to exploring the heat-refrigeration conversion performance of the electrolyte-flow EEC, from which optimal operation strategies and parameter impacts are determined. Additionally, the comparisons between the electrolyte-flow EEC and various existing heat-driven refrigerators are presented to emphasize its competitive performance.