Energy Efficiency of Reverse Electro Dialysis

摘要

Reverse Electro Dialysis (RED) is the salinity gradient energy retrieved from the difference in the salt concentration between sea and river water. In Reverse Electro Dialysis (RED) is a salt solution and fresh water are let through a stack of alternating cation and anion exchange membranes. The chemical potential difference between salt water and fresh water generates a voltage over each membrane and the total potential of the system is the sum of the potential differences over all membranes. The procedure works through difference in ion concentration instead of an electric field, which has implications for the type of membrane needed. In reverse electro dialysis, as in a fuel cell, the cells are stacked. A module with a capacity of 250 kW has the size of a transport container. Reverse electro dialysis is practically a salt battery that uses the transport of ions through membranes. It consists of an array of alternating positively charged exchange and negatively charged exchange membranes. Each and every membrane has fresh water on one side and salt water on the other side.