Optimization of the number of cell pairs to design efficient reverse electrodialysis stack

Abstract

Reverse electrodialysis (RED) is an emerging electrochemical process for harnessing salinity gradient power. For the commercialization of the RED process, the development of a highly efficient RED stack at a given flow rate is crucial. For this purpose, we first evaluated the performance of a RED stack according to the number of cell pairs at a given flow rate to improve the net power and specific energy (SE). Integrating the number of cell pairs at a given flow rate caused an increase in the electrical potential, and the net power was converged to the limiting value. The net SE was 0.06 kWh/m3 with 100 cell pairs at a flow rate of 100 mL/min. The levelized cost of electricity (<0.02 USD/kWh), an economic parameter, used to evaluate RED performance. The LCOE of RED stack with the highest net SE became lower than the highest net power density on reducing the membrane cost to below 20 USD/m2.