Salinity Gradient Power Experiment Using Reverse Electrodialysis

Abstract

A relatively new form of alternative energy known as reverse electrodialysis (RED) appears to be one of the promising energy sources of the future. This technology harvests the energy stored in the salinity gradient between two different liquids, and converts it directly into electric power. This power is generated by pumping water through an array of alternating pairs of cation and anion exchange membranes called cells. An experimental system was designed and assembled with cells 61 cm × 16.5 cm. Along with having much larger dimensions than the prototype systems reported in the literature, the design has an adjustable number of cells in the stack, allowing users to obtain test results at a variety of settings. Comparing the output of systems with few cells to systems with a higher number of cells will help us to optimize the stack size in terms of hydrodynamic losses. Tests results have shown a voltage output of 1.98V, 83% of the predicted output. The current and power produced by the system did not meet theoretical output levels, but our group believes a redesign of the electrode rinse system will bring these values up to expectations. Future works will benefit from the learning experience.

Silent Waterfalls – A Review of Salinity Gradient Osmotic Energy Conversion Technologies

“…The area enclosed by these curves represents the net energy output from this batch process. A Reverse Electrodialysis (RED) experimental system was designed and assembled by a group of undergraduate students at Wentworth Institute of Technology using 61 cm x 16.5 cm cells in the stack [27]. The stack design is adjustable similar to the plate heat exchangers, to allow users to obtain test results at a variety of settings.…”