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

• Ternary eutectic mixture of lauric–palmitic–stearic acid (LA–PA–SA) was prepared.
• LA–PA–SA/EP (expanded perlite) form-stable PCM was prepared with 55 wt% LA–PA–SA.
• LA–PA–SA/EP form-stable PCM showed a good thermal reliability and stability.
• Thermal conductivity of LA–PA–SA/EP increased by 95% by adding expanded graphite.

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 °C, 30.3 °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.