Water evaporation inspired biomass-based PCM from daisy stem and paraffin for building temperature regulation

Abstract

The addition of phase change materials (PCMs) to building wall can effectively regulate building temperature. However, the preparation of inexpensive, easily available, and environmentally friendly composite PCMs with high enthalpy is still a great challenge. Herein, inspired by water transportation and capillary evaporation of natural plants, we selected the widely distributed and economically available wild daisy stem as the raw material for the first time to prepare form-stable composite PCMs for building temperature regulation. A hierarchical porous skeleton material was prepared by high temperature carbonization and chemical modification of wild daisy stem, and then it was impregnated with paraffin to obtain a composite PCM. The results show that the chemical modification using ethanol creates a richer pore structure and increases the PCM loading amounts. The obtained composite PCM was thermally, chemically and cyclically stable with the phase change enthalpy and phase change temperature of 213.6 J/g and 40.1 °C, respectively. Finally, the composite was applied to the temperature regulation of buildings, the center temperature of the phase change model was 5.1 °C lower than that of the ordinary house, indicating the building with the addition of the as-prepared PCM to the walls had significant thermal buffering effect under a simulated light compared to ordinary building with rapid temperature change. Thus, the excellent storage capacity of this composite material gives it great potential for application in building temperature regulation.