Experimental Study on the Effect of Biochar Loaded With Paraffin Wax That Acts as a Phase Change Material and Epoxy-Coated Shape-Stabilized PCM Composite on Leakage Resistance and Shape Stability.

A significant problem in thermal storage is the leakage of phase-change materials (PCM) during their phase transitions. To overcome this, shape-stabilized composites were prepared by mixing biochar produced via an inert-gas-free pyrolysis process with PCM at weight percentages of 5%, 15%, 25%, 35%, and 45%. Then, only the top and bottom sides of the composites were coated with epoxy to a thickness of 1.5 mm, creating an epoxy-coated shape-stabilized paraffin composite. A scanning electron microscope (SEM) was used to examine the morphological alterations of these composite materials. Additionally, the bonding structure and chemical compatibility of the paraffin, biochar, and epoxy were examined using methods including Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). In the Brunauer-Emmett-Teller (BET) analysis, the biochar and non-leaching PJR500EPW35 composites yielded BET surface area values of 13.03 and 0.552 m 2 g -1 , respectively. The thermal conductivity values of the non-leakage PJR500EPW35 and PJR500EPW45 compositions were found to be 0.371 and 0.401 W m -1 k -1 , respectively. Similarly, the latent heat values were obtained as 40.06 and 13.69 J g -1 by Differential Scanning Colorimetry (DSC), respectively. In the Thermogravimetric analysis (TGA) test, PJR500EPW45, with the highest biochar weight percentage, exhibited 76.14% weight loss, demonstrating its thermal stability. In the Shore D hardness test, which assesses mechanical properties, the hardness values of the composites with 35% and 45% biochar were 64.0 and 64.8, respectively, indicating their strength. As the weight percentage of biochar in PCM raises, the thermal conductivity and thermal effusivity values begin to rise at regular intervals. Yet, even if the weight percentage of biochar in PJR500EPW25 is higher than in PJR500EPW05 and PJR500EPW15, the thermal conductivity and effusivity values in this composition decline. Biochar limits heat transfer in this composition, acting as a thermal insulator and lowering PJR500EPW25's efficiency. • PCM was injected into biochar and then epoxy-coated to prevent leakage of phase change material. Thermal properties and structural observations were examined. • Biochar was extracted successfully from the Prosopis juliflora plant's root • The fabrication of various samples designated PJR500EPW05, PJR500EPW15, PJR500EPW25, PJR500EPW35, and PJR500EPW45 was a combination of biochar and epoxy coated with PCM in the weight percentages of 5%, 15%, 25%, 35%, and 45%wt, respectively.