Development of Thermal Energy Storage Materials from Waste-Process Salts

TES is a technology that has been taken more importance in the last decades because of the increasing demand of clean energies, to avoid environment polluting by energy production from fossil sources. For that reason has been developed many materials for energy storage so far, but many of them are still much expensive and produce lesser energy than conventional fuels. In this research the potential use of waste-process salts, coming from the non-metallic mining industry in northern Chile, as heat storage materials were studied. The cost of these salts is low, and it corresponds to the transport cost to the application place mainly. The stability and thermophysical properties of two hydrated double salts, astrakanite and kainite, were determined by thermogravimetry and differential scanning calorimetry techniques. That information was useful to establish the range of application for these waste-salts as materials for sensible energy storage. The results proved that both salts are suitable for using as heat storage materials at low temperatures, 0 degrees C to 120 degrees C. Also it was found that the anhydrous phase of astrakanite can be used as solid TES material at higher temperatures, 350 degrees C to 530 degrees C. (c) 2014 The Authors. Published by Elsevier Ltd.