The Experts below are selected from a list of 6024 Experts worldwide ranked by ideXlab platform

Toshio Suzuki - One of the best experts on this subject based on the ideXlab platform.

  • melting and Solidification Point of fcc metal nanoparticles with respect to particle size a molecular dynamics study
    Chemical Physics Letters, 2010
    Co-Authors: Yasushi Shibuta, Toshio Suzuki
    Abstract:

    Abstract The phase transition between liquid droplets and solid nanoparticles of face-centered cubic (fcc) metals is investigated by the molecular dynamics simulation. Depression of both the melting and Solidification Points is negatively correlated with the inverse of particle radius. Polycrystalline nanoparticles are obtained by cooling and the polycrystalline structure causes a fluctuation in the trend of the melting Point with respect to particle size. It was found that the Gibbs–Thomson coefficient is proportional to the melting Point among various body-centered cubic (bcc) and fcc metals in the same matter, even though different interatomic potentials are employed between bcc and fcc metals.

  • effect of wettability on phase transition in substrate supported bcc metal nanoparticles a molecular dynamics study
    Chemical Physics Letters, 2010
    Co-Authors: Yasushi Shibuta, Toshio Suzuki
    Abstract:

    The phase transition between liquid and solid phases of the substrate-supported nanoparticles of iron, chromium, molybdenum and tungsten with size ranging from 2000 to 31 250 atoms was investigated by molecular dynamics simulation. Unidirectional Solidification and inward melting after surface melting occurred during cooling and heating, respectively. It was found that the depression of the melting Point due to size effect correlates with the shape of the nanoparticle (i.e. contact angle), whereas that for Solidification Point correlates with the interaction energy between the nanoparticle and substrate.

Yasushi Shibuta - One of the best experts on this subject based on the ideXlab platform.

  • melting and Solidification Point of fcc metal nanoparticles with respect to particle size a molecular dynamics study
    Chemical Physics Letters, 2010
    Co-Authors: Yasushi Shibuta, Toshio Suzuki
    Abstract:

    Abstract The phase transition between liquid droplets and solid nanoparticles of face-centered cubic (fcc) metals is investigated by the molecular dynamics simulation. Depression of both the melting and Solidification Points is negatively correlated with the inverse of particle radius. Polycrystalline nanoparticles are obtained by cooling and the polycrystalline structure causes a fluctuation in the trend of the melting Point with respect to particle size. It was found that the Gibbs–Thomson coefficient is proportional to the melting Point among various body-centered cubic (bcc) and fcc metals in the same matter, even though different interatomic potentials are employed between bcc and fcc metals.

  • effect of wettability on phase transition in substrate supported bcc metal nanoparticles a molecular dynamics study
    Chemical Physics Letters, 2010
    Co-Authors: Yasushi Shibuta, Toshio Suzuki
    Abstract:

    The phase transition between liquid and solid phases of the substrate-supported nanoparticles of iron, chromium, molybdenum and tungsten with size ranging from 2000 to 31 250 atoms was investigated by molecular dynamics simulation. Unidirectional Solidification and inward melting after surface melting occurred during cooling and heating, respectively. It was found that the depression of the melting Point due to size effect correlates with the shape of the nanoparticle (i.e. contact angle), whereas that for Solidification Point correlates with the interaction energy between the nanoparticle and substrate.

Zhengguo Zhang - One of the best experts on this subject based on the ideXlab platform.

  • a novel process for preparing molten salt expanded graphite composite phase change blocks with good uniformity and small volume expansion
    Solar Energy Materials and Solar Cells, 2017
    Co-Authors: Junwan Liu, Qianhao Wang, Ziye Ling, Xiaoming Fang, Zhengguo Zhang
    Abstract:

    Abstract Herein a novel process was explored for preparing molten salt/expanded graphite (EG) composite phase change material (PCM) blocks, which involves mixing a solid molten salt with EG thoroughly, compressing the mixture into a block with a designed shape and then heating the block to a temperature above the melting Point of the molten salt followed by cooling. An MgCl 2 -KCl eutectic salt was used as the PCM, and its EG-based composite PCM block was prepared by this process, in which the optimal mass fraction of the eutectic was determined to be around 85%. The microstructure of the MgCl 2 -KCl/EG composite PCM block containing 85% the eutectic shows a uniform distribution of the molten salt. The composite PCM block has a melting Point of 424.14 °C and a Solidification Point of 418.39 °C, and its latent heat values are 161.37 J/g for melting and 160.28 J/g for Solidification. Compared with the eutectic salt, the composite PCM block exhibits a reduction in supercooling by 3.7 °C and an enhancement in thermal conductivity by 11-fold. It has been verified that the composite PCM block possesses excellent thermal reliability. Furthermore, the composite PCM block has been compared with the one prepared by the conventional method (first adsorption and then compression). It is found that the composite PCM block fabricated by the novel process exhibits better uniformity and smaller volume expansion than the one obtained from the conventional method. The MgCl 2 -KCl/EG composite block shows great promise in high-temperature thermal energy storage systems, and this novel process is very suitable for preparing molten salt/EG composite PCM blocks.

Hlanze Philani - One of the best experts on this subject based on the ideXlab platform.

  • Integration of Phase Change Material-Based Storage in Air Distribution Systems to Increase Building Power Flexibility
    'Purdue University (bepress)', 2021
    Co-Authors: Hlanze Philani, Elhefny Aly, Jiang Zhimin, Cai Jie, Shabgard Hamidreza
    Abstract:

    This paper presents a novel energy storage solution by incorporating phase change material (PCM) in the building supply-air duct to increase a building’s thermal storage capacity. This solution has various advantages compared to PCM-integrated walls including more effective heat transfer (forced convection and greater temperature differentials). During off-peak hours, the system runs at a supply-air temperature below the material’s Solidification Point to charge the PCM with cooling energy. During on-peak hours, a higher supply-air temperature is utilized so that the stored energy can be discharged into the supply-air. This shifts a portion of the building’s cooling load from the on-peak hours to the off-peak hours. A numerical model for the melting and Solidification of PCM in the duct was developed and modified using experimental data. Whole building energy simulations were conducted by coupling the PCM model with EnergyPlus DOE prototypical building model in a Simulink co-simulation platform. Simulations were performed for three cities in different climate zones over a three-month cooling season (June to August), and the PCM storage reduced the on-peak energy consumption by 20-25%. The electricity cost and payback period were determined using current time-of-use electricity rates

  • Integration of phase change material-based thermal energy storage in air distribution systems to increase building power flexibility
    2020
    Co-Authors: Hlanze Philani
    Abstract:

    Thermal energy storage is one of the many strategies that are effective in alleviating the electrical power supply and demand imbalance issues on the electric grid, and buildings are a good place to implement such storage solutions because of their high electricity consumption. This thesis presents a novel energy storage solution by incorporating phase change material (PCM) in the building supply-air duct. The in-duct PCM storage has various advantages compared to PCMintegrated walls including more effective heat transfer (forced convection and greater temperature differentials). During off-peak hours, the system runs at a supply-air temperature below the material’s Solidification Point to charge the PCM with cooling energy. During on-peak hours, a higher supply-air temperature is utilized so that the stored energy can be discharged into the supply-air. This shifts a portion of building’s cooling load from the on-peak hours to the off-peak hours. A numerical model for the melting and Solidification of PCM in the duct was developed and modified using experimental data. Whole building energy simulations were conducted by coupling the PCM numerical model with EnergyPlus' DOE prototypical building model in a Simulink co-simulation platform. Simulations were performed for three cities in different climate zones over a three-month cooling season (June to August) and the PCM storage reduced the onpeak energy consumption by 20-25%. The electricity cost and payback period were determined using current time-of-use electricity rates

Junwan Liu - One of the best experts on this subject based on the ideXlab platform.

  • a novel process for preparing molten salt expanded graphite composite phase change blocks with good uniformity and small volume expansion
    Solar Energy Materials and Solar Cells, 2017
    Co-Authors: Junwan Liu, Qianhao Wang, Ziye Ling, Xiaoming Fang, Zhengguo Zhang
    Abstract:

    Abstract Herein a novel process was explored for preparing molten salt/expanded graphite (EG) composite phase change material (PCM) blocks, which involves mixing a solid molten salt with EG thoroughly, compressing the mixture into a block with a designed shape and then heating the block to a temperature above the melting Point of the molten salt followed by cooling. An MgCl 2 -KCl eutectic salt was used as the PCM, and its EG-based composite PCM block was prepared by this process, in which the optimal mass fraction of the eutectic was determined to be around 85%. The microstructure of the MgCl 2 -KCl/EG composite PCM block containing 85% the eutectic shows a uniform distribution of the molten salt. The composite PCM block has a melting Point of 424.14 °C and a Solidification Point of 418.39 °C, and its latent heat values are 161.37 J/g for melting and 160.28 J/g for Solidification. Compared with the eutectic salt, the composite PCM block exhibits a reduction in supercooling by 3.7 °C and an enhancement in thermal conductivity by 11-fold. It has been verified that the composite PCM block possesses excellent thermal reliability. Furthermore, the composite PCM block has been compared with the one prepared by the conventional method (first adsorption and then compression). It is found that the composite PCM block fabricated by the novel process exhibits better uniformity and smaller volume expansion than the one obtained from the conventional method. The MgCl 2 -KCl/EG composite block shows great promise in high-temperature thermal energy storage systems, and this novel process is very suitable for preparing molten salt/EG composite PCM blocks.