Reverse Electrodialysis Characteristic of the LiBr-ethanol-water Ternary Solution

Reverse electrodialysis heat engine (REDHE) has a large potential to convert low-grade heat into electrical energy. Working fluids with low distillation temperature and excellent ion migration properties are essential for the performance improvement of the REDHE. Here, we propose an ethanol-assisted LiBr aqueous to simultaneously decrease the distillation temperature and improve the performance of the REDHE. However, the unclear reverse electrodialysis (RED) characteristics of the ternary working fluid greatly block the application of the REDHE system. To this end, the ternary working fluid of LiBr-ethanol-water is respectively applied to a single-stage RED and multi-stage RED (MS-RED) stacks experiments for the first time, which clearly unveil the RED characteristics of the LiBr-ethanol-water ternary solutions under various working conditions. Both the solution compositions (solvent ratio and concentration) and the working parameters (flow velocity and feed temperature) are systematic studied. The concentration has the most excellent effect on the output performance of the RED stack, followed by temperature and flow rate. The single-stage RED could achieve a power density of 1.17 W m 2. Furthermore, the cumulative energy conversion efficiency of the MS-REDs is increased by 6.73 times from 1.48% to 11.45% as the stage number is stacked from 1 to 22 in series.