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

Abstract

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.

The Influence of Composition Ratio on the Thermal Performance Parameters of Eutectic Phase Change Materials: Experimental Research and Theoretical Prediction

“…The NRTL model introduces multiple non-random parameters on the basis of the Wilson model to further simulate the actual mixed eutectic process [31,32]. The calculation equation is as follows:…”

Normal alkane evaporation under vacuum: chain-length dependency and distillation from binary systems

“…Further, the mechanism by which the chain lengths of normal alkanes affect the evaporation process under vacuum, as well as the ideal (or practical) temperature setting for distillation of the alkane mixtures under reduced pressures need further elucidation. Differential scanning calorimetry analysis is useful for measuring solid −liquid phase transitions, [27][28][29][30] as it can be performed with less material volume change; however, detecting evaporation dynamics is rather difficult because the molecules become gases with large free volume during evaporation or boiling. This difficulty increases when analyzing the evaporation behavior under vacuum.…”