Temperature effects on energy production by salinity exchange
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AuthorAhualli, Silvia; Fernández, M. Mar; Iglesias, Guillermo R.; Delgado, Ángel V.; Jiménez Olivares, María Luisa
American Chemical Society
Electric double layerCapmixBlue energyCDLETemperature and salinity gradient
Ahualli, S.; et al. Temperature effects on energy production by salinity exchange. Environmental Science and Technology, (2014). [http://hdl.handle.net/10481/33397]
SponsorshipDepartamento de Física Aplicada; The research leading to these results received funding from the European Union 7th Frame-work Programme (FP7/2007-2013) under agreement No. 256868. Further Financial supports from Junta de Andalucía, project FQM 694, and Ministerio de Economía y Competitividad (Spain), project FIS2013-47666-C3-1-R.
In recent years, the capacitance of the interface between charged electrodes and ionic solutions (the electric double layer) has been investigated as a source of clean energy. Charge is placed on the electrodes either by means of ion-exchange membranes or of an external power source. In the latter method, net energy is produced by simple solution exchange in open circuit, due to the associated decrease in the capacitance of the electric double layer. In this work, we consider the change in capacitance associated with temperature variations: the former decreases when temperature is raised, and, hence, a cycle is possible in which some charge is put on the electrode at a certain potential and returned at a higher one. We demonstrate experimentally that it is thus viable to obtain energy from electric double layers if these are successively contacted with water at different temperatures. In addition, we show theoretically and experimentally that temperature and salinity variations can be conveniently combined to maximize the electrode potential increase. The resulting available energy is also estimated.