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FRINATEK-Fri prosj.st. mat.,naturv.,tek

Reverse ElectroDialysis; a Sustainable DC Power Source

Awarded: NOK 5.4 mill.

The energy of mixing between salt water (sea) and fresh water (river water) can be exploited in a salt power plant, by reverse electrodialysis or by pressure retarded osmosis. This projects concerns the first-mentioned technology. Ion-exchange membranes are used to control transport of sodium and chloride ions, to produce a cell voltage from change transport between different energy levels. We have also determined water transport and the heat that accompanies transport of ions and water. Both will effect the cell power. The electrolyte flow pattern with respect to the membranes is another variable we would like to investigate.

We propose to study a new way to exploit the energy source arising from mixing of sea water with brackish water, namely the reverse electrodialysis cell. This cell concept has been proposed for commercial use only very recently. A power density of almos t 1 W m^-2 membrane area has been reported. The project aims to raise this number by a factor three, by a systematic study of the cell's entropy production in combination with experimental tests. We propose to model the cell performance using membrane c haracteristic variables and typical flow fields, and to design and build a single cell power source accordingly. Based on this experience we want to build and test a cell stack. A successful cell will produce direct current power and may thus be ideal f or hydrogen production by water electrolysis, coping with both energy storage when power need is low (night-time) and transportation needs (supplying H2).

Funding scheme:

FRINATEK-Fri prosj.st. mat.,naturv.,tek