Effect of Fatty Acid on Melting and Solidification of Erythritol

Abstract One of the solutions to energy problems is the reuse of waste heat. One way to reuse waste heat is to use latent heat storage materials. Erythritol, of which melting point is the temperature range between 100 and 200°C, has attracted much attention as latent heat storage materials. However, as usual erythritol shows the large supercooling, its supercooling degree must be decreased to use for latent heat storage material. To achieve this, we have investigated the mixed erythritol with fatty acids as addition agents. Samples were prepared by physically mixing of erythritol and fatty acids such as (lauric acid, myristic acid, palmitic acid, and stearic acid). In this study, differential scanning calorimeter (DSC) was used (to evaluate the sample temperature program: 30→140→0→30°C, heating rate: 5°C/min, atmosphere: N 2 gas). The degree of supercooling was calculated from the DSC curve. And also, a camera was used to capture and discuss the freezing process. The erythritol physically mixed with fatty acids showed a higher freezing point and lower degree of supercooling than pure erythritol. The mixing myristic acid with erythritol significantly lowers the supercooling degree. The erythritol sample with palmitic acid or stearic acid did not show as low supercooling degree as that with myristic acid. Additionally, with lauric acid or myristic acid, the erythritol sample solidified simultaneously, while sample solidified separately with palmitic acid or stearic acid added. In summary, it was found that physical mixing of fatty acids and erythritol decreased in the supercooling degree. Furthermore, the crystallization temperatures of the sample with lauric acid or myristic acid were altered by changing the fatty acids.