Study of a novel ceramsite-based shape-stabilized composite phase change material (PCM) for energy conservation in buildings

Abstract

Building envelope with phase change material (PCM) embedded is able to optimize the thermal utilization and reduce energy consumption in buildings. However, the leakage of molten PCM, the low thermal performances (latent heat and thermal conductivity) and the inappropriate melting temperature limit the application of PCM in buildings. This work aims to propose a novel shape-stabilized composite PCM with encouraging thermal performances and effective encapsulation for applying to the building envelope. Firstly, a binary PCM with appropriate thermal properties for buildings was studied by using lauryl alcohol, stearic acid and nanoparticles, marked as LA-SA/Al2O3. Then this prepared LA-SA/Al2O3 was absorbed into ceramsite and encapsulated by styrene-acrylic emulsion and dry cement powder for shape-stability, a ceramsite-based PCM (LA-SA/Al2O3/C) was formed. Finally, the thermal-physical performances of the mixture of LA-SA/Al2O3/C and concrete were tested. The thermal performances of LA-SA/Al2O3 and LA-SA/Al2O3/C were measured by differential scanning calorimetry (DSC), the chemical and thermal stabilities were tested by Fourier transform infrared (FT-IR) and thermogravimetric (TG). Results show that the optimal proportion for LA-SA/Al2O3 is 82 wt% LA + 18 wt% SA with 0.5 wt% Al2O3 nanoparticle, for which the melting temperature and latent heat are 21.3 °C and 205.9 kJ/kg respectively. The LA-SA/Al2O3/C has the ability to prevent the leakage of PCM, owning the excellent melting latent heat of 133.4 kJ/kg, which is relatively high comparing with the values in other references. The concrete based-CPCM with 15% LA-SA/Al2O3/C embedded shows satisfied mechanical performance and has great potential to reduce the indoor temperature fluctuation caused by outdoor ambient, and cut down the energy consumptions of heating and cooling devices in buildings.