Fabrication of a novel shape-stabilized composite phase change material based on multivariate supporting materials by using typical solid wastes

Abstract

In this study, palmitic acid (PA)/hybrid multivariate typical solid wastes (MTSW) phase change materials (PCMs) were fabricated by integrating PA into MTSW via a facile direct impregnation method to overcome the leakage of PA. The hybrid MTSW was composed of biomass solid wastes (BSW), iron tailings (IT) and diatomite (DT) at different mass ratios. Simultaneously, carbon nanotubes (CNT) was employed to enhance the thermal conductivity of the PCMs, and then the novel PA/MTSW/CNT composite was firstly prepared. The preparation, shape-stabilization level, morphologies, chemical compatibility, thermal properties and thermal conductivity of these composite PCMs were systematically characterized by tableting leakage tests, scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hot dist and cooling test method. It was found that the MTSW could adsorb 30 wt% PA without any PA leakage and the composites can keep form-stable with mass fraction proportion of 3:2:2:3 for PA, BSW, IT and DT, respectively. The SEM images showed PA was well infiltrated into pore structure of MTSW which had good loading capacity to adsorb PA. FTIR analysis indicated that no chemical reaction had occurred among the components of composite PCMs. The DSC results suggested that the melting points were 63.65 °C and 63.08 °C for PA/MTSW and PA/MTSW/CNT (4 wt%) form-stable phase change materials (FSPCM), respectively. Correspondingly, the latent heats were 55.36 J/g and 53.10 J/g for PA/MTSW and PA/MTSW/CNT FSPCM, respectively. The TGA results showed that PA/MTSW/CNT FSPCM exhibited better thermal stability than pure PA. Compared with pure PA, the thermal conductivities of PA/MTSW/CNT were increased by 25.71%, 36.44% and 91.35% by CNT doping 2, 4 and 6 wt%, respectively. In addition, the heat storage and discharge time of PA/MTSW/CNT were reduced appreciably. In Conclusion, the as-prepared FSPCM has very good properties and a good application prospect in the field of energy-saving building.