Metal, carbon and conducting polymer nanoparticles are blended with organic phase change materials (PCMs) to enhance the thermal conductivity, heat storage ability, thermal stability and optical property. However, the existing nanoparticle are expensive and need to be handle with high caution during operation as well during disposal owing to its toxicity. Subsequently handling of solid waste and the disposal of organic PCM after longevity usage are of utmost concern and are less exposed. Henceforth, the current research presents a new dimension of exploration by green synthesized nanoparticles from a thorny shrub of an invasive weed named Prosopis Juliflora (PJ) which is a agro based solid waste. Subsequently, the research is indented to decide the concentration of green synthesized nanoparticle for effective heat transfer rate of organic PCM (Tm = 35-40 °C & Hm = 145 J/g). Furthermore, an in-depth understanding on the kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM after usage via Coats and Redfern technique is exhibited. Engaging a two-step method, we fuse the green synthesized nanomaterial with PCM to obtain nanocomposite PCM. On experimental evaluation, thermal conductivity of the developed nanocomposite (PCM + PJ) increases by 63.8% (0.282 W/m⋅K to 0.462 W/m⋅K) with 0.8 wt% green synthesized nanomaterial owing to the uniform distribution of nanoparticle within PCM matrix thereby contributing to bridging thermal networks. Subsequently, PCM and PCM + PJ nanocomposites are tested using thermogravimetric analyzer at different heating rates (05 °C/min; 10 °C/min; 15 °C/min & 20 °C/min) to analyze the decomposition kinetic reaction. The kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM and its nanocomposite of PCM + PJ provides insight on thermal parameters to be considered on large scale operation and to understand the complex nature of the chemical reactions. Adopting thirteen different chemical mechanism model under Coats and Redfern method we determine the reaction mechanism; kinetic parameter like activation energy (Ea) & pre-exponential factor (A) and thermodynamic parameter like change in enthalpy (ΔH), change in Gibbs free energy (ΔG) and change in entropy (ΔS). Dispersion of PJ nanomaterial with PCM reduces Ea from 370.82 kJ/mol-1 to 342.54 kJ/mol-1 (7.7% reduction), as the developed nanomaterial is enriched in carbon element and exhibits a catalytic effect for breakdown reaction. Corresponding, value of ΔG for PCM and PCM + PJ sample within heating rates of 05-20 °C/min varies between 168.95 and 41.611 kJ/mol-1. The current research will unbolt new works with focus on exploring the pyrolysis behaviour of phase change materials and its nanocomposite used for energy storage applications. This work also provides insights on the disposal of PCM which is an organic solid waste. The thermo-kinetic profile will help to investigate and predict the optimum heating rate and temperature range for conversion of micro-scale pyrolysis to commercial scale process.
Effective utilization and conservation of freshwater is a global concern due to the rapid population growth and industrial usage. To address this challenge, various approaches have been developed and implemented to convert brackish water into freshwater and meet the global water demand. This study introduces hexagram-shaped aluminum fins attached to a powder-coated basin to improve the freshwater production rate of stepped solar still. The experiment involved testing the modified stepped solar still (MSSS) equipped with hexagram fins and the conventional stepped solar still (CSSS) without hexagram fins during summer days at the Sathyamangalam location (11.49° N, 77.27° E). A mathematical model was used to analyze the performance of the solar stills, and the simulation results were validated by comparing CSSS and MSSS in terms of their freshwater production. The results indicate that the productivity of CSSS increased by 40% using hexagram fins, and the MSSS with hexagram fins produced a maximum of 4.45 l/m2 of fresh water daily. The annual performance of MSSS and CSSS in the experimental location reveals a 12.6% reduction in the payback period of the solar still due to the presence of fins. The study recommends using fins in solar stills in hot climates for efficient and cost-effective water desalination applications to achieve sustainable development objectives while reducing carbon emissions.