Studies on Salt Hydrate for Latent Heat Storage, II. Eutectic Mixture of Pseudo-binary System CH3CO2Na·3H2O–CO(NH2)2

With a view of developing latent heat storage materials, mixtures of pseudo-binary system, CH3CO2Na·3H2O–CO(NH2)2 (sodium acetate trihydrate–urea) were subjected to differentital scanning calorimetry, and the partial phase diagram for ternary system CH3CO2Na–CO(NH2)2–H2O at ambient pressure was constructed. The eutectic mixture, containing 0.6 mass fraction of CH3CO2Na·3H2O and 0.4 mass fraction of CO(NH2)2, melts congruently at 31.5 °C with a heat of fusion of 226 J/g, which is larger than the heat of fusion of CaCl2·6H2O, 180 J⁄g. Thus, mixtures of system CH3CO2Na·3H2O–CO(NH2)2 are promising for solar energy storage.