Development of novel phase change materials based on methyl laurate and fatty acids for low-temperature applications

In response to the urgent need for latent heat thermal energy storage (LHTES) in the cryogenic field and the utilization of renewable energy sources, three novel eutectic phase change materials (PCMs) have been successfully developed. These materials, methyl laurate (ML)/lauric acid (LA), methyl laurate/myristic acid (MA), and methyl laurate/palmitic acid (PA), belong to the eutectic system of fatty acid methyl ester (FAME) and fatty acid. With a specific composition, these binary mixtures have desired melting temperatures, high melting enthalpy, and stable thermal performance. The phase diagrams of the eutectics were analyzed to obtain precise eutectic mass ratios. Theoretical predictions of the eutectic mass ratios and thermal properties were validated and determined through differential scanning calorimetry (DSC) and the hot-disk method. The ML-LA, ML-MA, and ML-PA mixtures had onset melting temperatures of 4.19°C, 5.45°C, and 5.69°C, respectively, with corresponding enthalpy of fusion values of 185.43, 190.47, and 194.39 J/g. The cycling stability test results showed that these mixtures had good thermal stability. The thermophysical properties and molecular structure of the mixtures were analyzed, indicating that these new mixtures of ML and fatty acids are suitable for low-temperature LHTES applications such as cold compresses and thermal-regulating textiles. This study provides insight into developing new PCMs that can meet the demand for LHTES in the cryogenic field and the utilization of renewable energy sources.