Thermodynamic investigation of the Ca(NO3)(2)-NaNO3-KNO3 system for solar thermal energy storage

•The phase diagram of the Ca(NO3)2–NaNO3–KNO3 system is predicted.•The predicted ternary mixture is 32.4 % Ca(NO3)2–12.4 % NaNO3–55.2 % KNO3.•The predicted melting point of this system and that determined experimentally are in excellent agreement.•The predicted ternary mixture has a lower melting point.