Clean production of biochar-based sustainable lightweight PCM composites: Effect of pyrolysis parameters on thermal and energy storage

In recent years, many strategies have been developed to prevent Phase change material (PCM) leakage, but it remains a major challenge to develop PCMs with the advantages of low production costs, sustainability, reusability, and the use of fillers made from waste biomass. Paraffin wax, an organic Phase change material, was used as a thermal storage material. To reduce the total cost of production and produce inexpensive biochar, biomass extracted from the root of the Prosopis juliflora plant was subjected to a pyrolysis process with low oxygen and without the use of inert gases. In order to investigate the PCM adsorption properties of the biochar, two types of biochars, PJR 400 and PJR 500, were prepared by varying the pyrolysis temperature to 400 °C and 500 °C. Then, using the direct impregnation technique, this biochar was blended with PCM at various weight percentages, i.e. 5%, 15%, 25%, 35%, and 45%. The surface area values of PJR500 and PJR400 biochars prepared at two different temperatures were found to be 4.451 and 2.423 m2/g, respectively. After Brunauer-Emmett-Teller (BET) analysis, SEM, XRD and FTIR measurements were used to analyze and verify the morphological and chemical properties of the PCM blends and biochars. DSC, thermal conductivity and leakage studies were conducted to determine the performance and heat storage capacity of the PCM, and the results were compared. In addition to preventing leakage, the PJR 500 biochar blend with PCM at 45% also had thermal conductivity and heat storage enthalpy values of 90.24 J/g and 0.463 W/mk, respectively.