Incorporation of phase change material and carbon nanofibers into lightweight aggregate concrete for thermal energy regulation in buildings

摘要

A kind of electric thermal energy storage concrete (ETESC) was firstly developed by using encapsulated thermal storage aggregate (ETSA) and carbon nanofibers (CNFs). ETSA was fabricated by incorporating phase change materials (PCMs) into ceramite or pumice and coated by a multi-layer shell to prevent the leakage of PCMs. Scanning electron microscope (SEM), Fourier transformation infrared spectroscopy (FTIR) and diffusion-oozing grids testing results showed that PCMs can be well impregnated into pores and have good physical and chemical compatibility with porous supports. Furthermore, when ordinary lightweight aggregates were completely replaced by ETSA in concrete, the compressive strength of ETESC still exceeded 5 MPa, indicating that ETESC is suitable for being used as thermal insulation building envelopes. In comparison with the control lightweight aggregate concrete, the maximum increment of thermal conductivity with ETSA incorporated reached 15.8%. Moreover, the results of electric thermal storage performance indicated that the maximum temperature reductions of the center point in the room model equipped with ceramsite-based and pumice-based ETESC reached 4.7 °C and 8.7 °C, respectively. Therefore, this developed electric thermal storage concrete has a potential for being applicable as a self-heating and thermal energy regulation material in buildings.