Experimental Measurements and Thermodynamic Modeling of Melting Temperature of the Binary Systems n-C₁₁H₂₄-n-C₁₄H₃₀, n-C₁₂H₂₆-n-C₁₃H₂₈, n-C₁₂H₂₆-n-C₁₄H₃₀, and n-C₁₃H₂₈-n-C₁₅H₃₂ for Cryogenic Thermal Energy Storage

In this study, the phase diagrams for the binary systems of n-C₁₁H₂₄-n-C₁₄H₃₀, n-C₁₂H₂₆-n-C₁₃H₂₈, n-C₁₂H₂₆-n-C₁₄H₃₀, and n-C₁₃H₂₈-n-C₁₅H₃₂ were experimentally investigated to employ potential phase change materials (PCMs) for cryogenic applications. Besides, the phase diagrams were theoretically obtained on the basis of the ideal solubility and UNIFAC models, and the UNIQUAC, Wilson, and NRTL models were applied to build correlations between experimental and predicting values. The results show that the compositions of the eutectic points appear at 10 wt % C₁₄ for the C₁₁-C₁₄ system, 17.8 wt % C₁₃ for the C₁₂-C₁₃ system, 18 wt % C₁₄ for the C₁₂-C₁₄ system, and 10 wt % C₁₅ for the C₁₃-C₁₅ system with eutectic temperatures of 246.85, 257.75, 260.45, and 265.55 K, respectively. Moreover, the melting temperatures calculated using the theoretical models are in good agreement with the experimental results. The average relative deviations for the C₁₁-C₁₄ system and C₁₃-C₁₅ systems are merely 0.3814% and 0.3220%, respectively, by using the NRTL model. Simultaneously, the minimum relative deviations for the C₁₂-C₁₃ and C₁₂-C₁₄ binary systems are 0.3649% for the ideal solubility model and 0.4856% for the UNIFAC model. Finally, upon comparing the predicted results of the studied binary systems using the results of the five models, we find that the UNIFAC model provides the most accurate results for the melting temperatures.