Investigation of a novel bio-based phase change material hemp concrete for passive energy storage in buildings

In latent heat storage, energy is stored through the change of state of a material and then released when the material returns to its original phase. Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The objective of this study is the fabrication and characterization of a biosourced PCM hemp concrete. Hemp shives are vacuum impregnated with CA with an incorporation rate of 53%. The resulting shape-stabilized hemp shives/CA composite is used to fabricate PCM hemp concrete. The morphology and thermophysical properties of the materials at all stages (from pure CA to hemp concrete PCMs) are characterized using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and compared to the reference state (hemp concrete without PCMs). Results of the DSC measurement indicated melting and solidification temperatures of hemp shives/CA composite of 28.9 degrees C and 23 degrees C, respectively and enthalpy of melting and solidification calculated as 78.7 and 76.4 J.g(-1), respectively. The TGA/dTG results showed that the form stable composite exhibits good thermal stability under 170 degrees C, making it suitable for building application. The thermal performances of PCM hemp concrete are evaluated in a climatic chamber and compared to those of a reference hemp concrete. Results showed a good thermoregulation capacity of the PCM hemp concrete with a maximum time shift of 30 min and a temperature difference between reference and PCM hemp concrete of about 4.6 degrees C. Featured Application: Passive latent heat storage for building applications, thermal comfort.