Lauric-palmitic-stearic acid/expanded perlite composite as form-stable phase change material: Preparation and thermal properties

Based on theoretical calculation, lauric-palmitic-stearic acid ternary eutectic mixture (LA-PA-SA) with a suitable phase change temperature was prepared firstly. Then LA-PA-SA was incorporated with expanded perlite (EP) by vacuum impregnation method. The maximum mass ratio of LA-PA-SA retained in EP was found as 55 wt%. The microstructure and chemical characterization of LA-PA-SA/EP form-stable phase change material (PCM) was characterized by scanning electron microscope and Fourier transformation infrared spectroscope, and the results showed that LA-PA-SA was uniformly dispersed into the pores of EP by physical interaction. The melting and freezing temperatures and latent heats of LA-PA-SA/EP were measured by a differential scanning calorimeter as 31.8 degrees C, 30.3 degrees C and 81.5 J/g, 81.3 J/g respectively. The result of thermogravimetry analysis revealed that the form-stable PCM had a good thermal stability. Thermal cycling test showed that there was no significant change of the thermal property of LA-PA-SA/EP after 1000 thermal cycling. Moreover, the thermal conductivity of LA-PA-SA/EP was increased by 95% by adding 2 wt% expanded graphite, and the thermal energy storage/release rates were also increased. All results indicated that the prepared LA-PA-SA/EP form-stable PCM can be considered as a potential material for building energy conservation due to satisfactory thermal properties, high thermal conductivity, good thermal reliability and stability. (C) 2014 Elsevier B.V. All rights reserved.