Inorganic Salt Hydrates as Phase Change Materials (PCM) for Thermal Energy Storage in Solar Installations

The authors present a general idea of using inorganic salt hydrates in solar installations. A key role in this selection is played by thermophysical parameters, so the authors review their test methods and in turn characterize them for the most promising salt hydrates. Next, the authors describe the advantages and disadvantages of inorganic salt hydrates and indicate possibilities for their improvement. The use of salt hydrate converters in PV installations significantly improves the efficiency of photovoltaic modules. We show that at least 18 salt hydrates are promising for solar applications with the best ones being Sodium Hydrogen Phosphate Dodecahydrate, Sodium Carbonate Decahydrate and Calcium Chloride Hexahydrate. The selection of a test method for determining the thermophysical parameters of salt hydrates should be individual depending on the research objective. Comparing the methods presented, we believe that it is the DSC and DTA methods that provide the most accurate and repeatable results.