Electrodialysis reversal or pressure retarded osmosis cell with heat pump

Abstract

A method and system for generating electricity or hydrogen from thermal energy is disclosed. The method includes separating a first salt solution from a second salt solution by a selectively permeable membrane (104), receiving thermal energy from a heat source by the first salt solution and / or the second salt solution, mixing the first salt solution and the second salt solution in a controlled manner, and capturing at least a portion of the salinity gradient energy as electricity as the salinity difference between the first salt solution and the second salt solution decreases. The method further includes transferring thermal energy from the first salt solution to the second salt solution by a heat pump (320), increasing the salinity difference between the first salt solution and the second salt solution. The method and system can include regeneration processes such as membrane distillation, forward osmosis, electrodialysis, salt evaporation, and / or salt decomposition for further energy efficiency and power generation.

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