Phase diagram of the system

The phase diagram of the quaternary system KNO3–LiNO3–Mg(NO3)2–H2O was simulated over the temperature range from 273 to 333 K by a Pitzer–Simonson–Clegg model, whose parameters were determined by fitting to experimental solubility and water activity data of the binary systems KNO3–H2O, LiNO3–H2O, Mg(NO3)2–H2O and the ternary systems KNO3–LiNO3–H2O, KNO3–Mg(NO3)2–H2O, LiNO3–Mg(NO3)2–H2O. Three new eutectic points with melting points within room temperatures were found in these systems, which could be used as candidates for storing heat from low temperature heat resources. Exothermal and endothermal behaviors of the predicted phase change materials were measured. Results show that the predicted phase change materials possess excellent heat storage and release ability.