Optimization of the Energy Extraction Process From Capacitive Deionization Cells

Capacitive deionization cells, already present in different industrial applications, can also be used to generate electrical energy by alternating salt and fresh water flows (CapMix cells). Unfortunately, the performance inherent to these cells gives rise to large losses when extracting the energy harvested. This article provides contributions to the appropriate characterization of CapMix cells and to the optimization of the energy-extraction process. The optimization analysis carried out concludes that the best strategy consists of extracting the energy by discharging the cell with a constant current to minimize cycle times. This determines the operation conditions of the power converter that will be eventually used for that task. A test bench has been developed that allows the theoretical analysis presented to be experimentally validated.