Valorization of waste biomass derived activated carbon @expanded graphite for intensification of thermal characteristics of RT24 phase change material through shape-stabilization

The basic philosophy of this work is to create cleaner energy alternative materials for solar thermal energy storage applications. This experimental evaluation focuses on elevating the thermal characteristics of Rubitherm paraffin (RT24) by incorporating a hybrid matrix for shape stabilization. The hybrid matrix was fabricated by infusing expanded graphite (EG) (5 wt% and 10 wt%) into carbonized sugar beet pulp and vinasse wastes (BAC). The shape-stabilization of RT24 was carried out in vacuum to achieve uniform dissipation. The synthesized hybrid supporting matrices were adequately porous with highest BET surface area of 411.25 m2/g after adding EG(5 wt%) to BAC. According to TGA analysis BAC/RT24, BAC@5%EG/RT24(45 %) and BAC@10%EG/RT24 (60 %) were highly resistant to heat with corresponding mass loss of 39.4 %, 44.7 % and 59.8 % at around 280 degrees C. In accordance with XRD and FTIR analysis PCM composites have not displayed structural or chemical transformation due to the presence of EG or BAC. The melting and solidifying latent heat values of BAC@10% EG/RT24(60 %) were measured as 132.15 J/g and 129.42 J/g respectively. Also, BAC/RT24, BAC@5%EG/RT24 (45 %) and BAC@10%EG/RT24(60 %) have revealed high thermal reliability after performing 1000 thermal cycles with a variation of about 3 % in melting latent heat, thus signifying their adaptability into latent heat storage (LHS) systems. Thermal conductivity of the shape-stable BAC/RT24 composite was increased by 300 % compared to pure RT24 PCM as a result of adding 10 wt% EG to the composite. Especially BAC@10%EG/RT24 (60 %) composite can be utilized as cleaner energy alternative material for building solar thermal implementation because it had relatively higher LHS capacity and thermal conductivity value.