Abstract

Climate change is expected to have irreversible impacts if greenhouse gas emissions are not immediately reduced. Among direct ways to moderate CO2 emissions into the atmosphere, one option is to meet the electricity demand in a clean and environmentally friendly way, such as using solar energy. Intermittence and instability of solar energy could be solved by linking this technology with thermal energy storage (TES) systems, which can be classified as sensible heat, latent heat, and thermochemical heat storage. Search for new materials available as TES media still represents a challenge in energy research. Usage of by-products and wastes as TES materials, could promote implementation of sustainable and profitable thermal storage systems. These low-cost materials could also be considered ecofriendly, since they are not direct contributors to carbon dioxide emissions, and their use reduces material accumulation and, consequently, pollution due to non-metallic mining industry waste. Therefore, this chapter addresses basic concepts related to theory and applications of TES systems. Examples of problems and challenges for implementation of such technologies are also provided, especially progress in development of inorganic salt-based waste materials (bischofite, potassium carnallite, kainite, and astrakanite), produced from non-metallic mining activities in the North of Chile, as well as proposals related to potential optimization methods and future development perspectives of sustainable materials for TES technologies.