An approach to utilize date seeds biochar as waste material for thermal energy storage applications

Abstract

Rapid industrialization as a consequence of the green revolution and population proliferation has resulted in massive solid waste generation as well as greater energy consumption demands. With increasing energy demand coupled with ever-increasing waste generation, the time has come to think about global sustainability. The practice of green technology which is ecologically benevolent might be the foothold of waste management that renders resolutions. Therefore, waste valorization in sustainable energy forms can bring up an economic and suitable solution for the sustainability of civilization. Contemplating that, an attempt has been made to utilize date seeds as waste material for shape stabilization of phase change materials (PCMs) for effective thermal energy storage applications. Date seeds (DS) are ground to powder and pyrolyzed into porous biochar, having high porosity and channel-like morphology with a BET surface area of 187.07 m2/g. The PCM composites are accomplished by introducing capric acid (CA) into synthesized biochar (DSB). CA has been incorporated in 2:1 and 3:1 ratios into DSB and the thermal stability along with performance of the synthesized DSCA composites have been evaluated for their suitable applications. The 3:1 CA to DSB ratio has been realized as optimum for the highest accommodation of CA into DSB. Higher heat charging and discharging enthalpies of 72.4 and 71.76 J/g are accomplished for 1–3 DSCA sample as well as encapsulation efficiency and ratio are found to be 43.79 % and 43.96 %, respectively. During phase transitions, excellent leakage resistance and congruent heat charging and discharging capabilities have been manifested by the DSCA samples. The extraordinary performances displayed by the DSCA PCM composites are attributed to the surface tension, capillary action, space confinement and surface functionalities offered by the porous biochar.