Thermal Properties and Reliabilities of Lauric Acid-Based Binary Eutectic Fatty Acid as a Phase Change Material for Building Energy Conservation.

Thermal properties, stability, and reliability of lauric acid-based binary eutectic mixtures for building energy efficiency were studied. The eutectic points and phase change performance of these binary PCMs were obtained as follows: (1) For lauric acid-myristic acid, the mass eutectic point is 70 wt % LA/30 wt % MA. (2) For lauric acid-palmitic acid, the eutectic point is 79 wt % LA/21 wt % PA. (3) For lauric acid-stearic acid, the eutectic point is 82 wt % LA/18 wt % SA. The eutectic PCMs have a melting enthalpy of 166.18, 183.07, and 189.50 J·g and a melting temperature of 35.10, 37.15, and 39.29 °C for lauric-myristic acid, lauric-palmitic acid, and lauric-stearic acid binary eutectic PCMs, respectively. The experimental results are very close to the theoretical results. Moreover, from FT-IR and XRD investigations, we realized that during the preparation of the lauric acid-based binary eutectic fatty acids, no new functional groups were produced. Besides, the TG illustrated that the LA-MA eutectic PCMs, LA-PA eutectic PCMs, and LA-SA eutectic PCMs exhibit excellent thermal stability below 126.51, 135.7, and 110.08 °C, respectively. Finally, lauric acid-based binary eutectic PCMs still show excellent thermal properties and chemical structure after 500 hot and cold cycles. All in all, as a novel material for building energy conservation, lauric acid-based binary eutectic PCMs have broad prospects and good practicability.