Designing and Characterization of Low-Temperature Eutectic Phase Change Materials Based on Alkanes

Mikołaj Więckowski,Marek Królikowski

doi:10.1021/acs.jced.1c00783

Abstract

The research presented here focuses on investigating the relationship between the structure of components and the eutectic temperature of binary systems designed as phase change material (PCM). For two-component systems containing long-chain alkanes (n-tetradecane, n-pentadecane, n-hexadecane, or n-heptadecane) and decanoic acid or 1-decanol, experimental data of the solid–liquid equilibrium are presented. The collected data were used to determine the composition and temperature of eutectic mixtures that are promising PCMs with a narrow melting point range. An essential aspect of this work is to confirm the possibility of determining eutectics of similar systems using predictive models, mainly the modified Dortmund universal quasichemical functional group activity coefficients method, without the need to perform expensive and time-consuming experimental research. The experiments were supplemented with the physicochemical characteristics (density and viscosity) of the liquid mixtures. The obtained PCM was closed in a polymer matrix to prevent material leakage into the environment, and the obtained composite materials were characterized by using scanning electron microscopy and differential scanning calorimetry techniques.

Highlights

The unbridled development of technology requires new, more efficient energy sources and transformation or storage methods
E-phase change material (PCM) containing C14 and decanoic acid is distinguished by the highest enthalpy and fulfills the requirements for tissue storage, while all eutectic mixtures (EMs) possess a latent heat greater than 150 J·g−1 and fusion temperatures in the range of those used in commercial refrigeration
Each proposed system is characterized by positive deviations from ideality, which contribute to a higher value of latent heat

Summary

■ INTRODUCTION

The unbridled development of technology requires new, more efficient energy sources and transformation or storage methods. Experimental solubility data points (x1,T) of systems {nalkane (1) + 1-decanol (2)} and {n-alkane (1) + decanoic acid (2)} are listed in Tables S1 and S2, respectively. The high value of deviations results in a significant difference between the predicted and actual eutectic compositions, which indicates that using the ideal solubility model for predicting the SLE with alkanes and fatty acids or alcohols is unjustified and models involving activity coefficients are necessary. In the case of mixtures containing decanoic acid with a higher melting point, the eutectic composition is dominated by the alkane with a high enthalpy of melting

C14 C15 C16 C17

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES