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Background: High-temperature phase change materials (PCMs) are increasingly recognized for their potential in applications such as solar energy utilization, industrial waste heat recovery, and power load regulation. These materials can store and release significant amounts of latent heat, making them highly efficient for thermal energy storage. Purpose: This study aims to propose and analyze a novel structure to enhance latent heat energy storage using a graphite sheet combined with a PCM (KNO3-NaNO3) with a melting point of 220 K. The focus is on improving heat transfer efficiency and understanding the parameters affecting the exothermic process. Research Design: A numerical simulation approach was employed, using Fluent 7.1 software to analyze the exothermic process. The simulation method was validated with two examples before being applied to study the energy storage system incorporating graphite sheets. Study Sample: The study analyzed the performance of a high-temperature thermtotal energy storage (HTTES) system using graphite sheets of varying thicknesses, tube spacing, tube temperatures, and PCM thermal conductivities. Data Collection and/or Analysis: The study utilized numerical simulations to examine how different parameters i.e. thickness of graphite sheets, spacing between tubes, tube temperatures, and the thermal conductivity of PCM—affect heat transfer efficiency and exothermic time. Results: The integration of graphite sheets with a thickness of 2 mm was found to significantly improve heat transfer efficiency. The results indicated that increasing the spacing between graphite sheets and tube diameter influenced the total exothermic time. A logarithmic relationship was observed between the thermal conductivity coefficient and exothermic time, suggesting diminishing returns beyond 3.5 W/(m·K). Additionally, increasing the quantity of graphite sheets enhanced heat transmission and overall system efficiency. Conclusions: The study provides valuable insights into the performance of HTTES systems, demonstrating that incorporating graphite sheets can significantly enhance heat transfer and system efficiency. These findings guide the design of more effective thermal energy storage systems, supporting the broader adoption of HTTES technologies and contributing to the transition toward sustainable energy solutions. Further research and development in this field are essential to drive advancements and promote the widespread implementation of high-temperature thermal energy storage systems. Practical applications: The enhanced heat transfer techniques developed in this research offer practical applications across various sectors. These techniques, utilizing PCMs and innovative graphite structures, enhance the efficiency and reliability of high-temperature thermal energy storage systems. This advancement enables continuous power generation in concentrated solar power (CSP) plants, optimizes energy utilization in district heating and cooling systems, and improves industrial waste heat recovery. By implementing these techniques, energy costs can be reduced, system performance can be optimized, and greenhouse gas emissions can be lowered, contributing to a more sustainable energy future. [ABSTRACT FROM AUTHOR]

In this study, three representative materials, wood, paper, and cloth from municipal solid waste, were studied separately in an atmospheric fluidized bed gasifier. The effects of different feedstock, equivalence ratio, gasification temperature, and calcium carbonate presence on syngas composition, the lower heating value, and carbon conversion efficiency were investigated at different operating temperatures (800-950 °C), and the equivalence ratio range from 0.2 and 0.5. As the equivalence ratio increased, the yields of syngas and its lower heating value decreased, whereas the CO2 yield and carbon conversion efficiency increased generally from wood gasification. Higher gasification temperature favored enhancing the CO and H2 yield and lowering the CO2 yield while the lower heating value and carbon conversion efficiency of syngas increased. Different variations of CO2 yield and the lower heating value of syngas were observed in different feedstock gasification. CaCO3 was more supportive for enhancing the yields of syngas components (H2, CO, and CH4) and lowering the CO2 yield, while a lower heating value of syngas was also increased from different feedstock gasification. However, an optimum temperature of 900 °C was the highest lower heating value of syngas, reaching 8000 kJ/Nm3 from wood gasification. [ABSTRACT FROM AUTHOR]

This paper describes the influence of gas pressure on the conversion of O2 to O3 and the ozone production efficiency in a multichannel dielectric barrier discharge (DBD) reactor utilizing positive and negative pulses. Results show that conversion of O2 to O3 is continuously enhanced by the increase of gas pressure (0.1-0.24 MPa) while the rising speed of oxygen conversion with the increasing gas pressure at fixed specific input energy is reduced above 0.15 MPa. The maximum ozone generation efficiency is increased with increasing gas pressure (0-0.2 MPa) while positive pulse exhibits higher energy efficiency. The maximum ozone generation efficiency is suppressed with further increase of gas pressure (0.2-0.24 MPa) while no significant difference in ozone generation efficiency is observed for two unipolar pulse modes. Results also show that 0.2 MPa is the optimal working gas pressure to obtain the maximum ozone generation efficiency and increasing gas pressure would lead to remarkable increase of ozone generation efficiency for ozone production at high energy densities in multichannel DBD. [ABSTRACT FROM AUTHOR]