The Experts below are selected from a list of 6408 Experts worldwide ranked by ideXlab platform

Stella P. Jesumathy - One of the best experts on this subject based on the ideXlab platform.

  • an experimental study on heat transfer characteristics of paraffin wax in horizontal double pipe heat latent heat storage unit
    Journal of The Taiwan Institute of Chemical Engineers, 2014
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh, S Jegadheeswaran
    Abstract:

    Abstract An experimental study is conducted to investigate the Melting and solidification processes of paraffin wax as a phase change material (PCM) in horizontal double pipe heat latent heat storage unit. The present work on phase change process includes study of temperature variations along the axial distances in PCM, determination of heat transfer coefficient as well as the heat flow rate. A series of experiments was conducted to investigate the effect of increasing the inlet temperature and the mass flow rate of the heat transfer fluid (HTF) both on the charging and discharging processes of the PCM. The experimental results show that the PCM melts and solidifies congruently, and the Melting Front moves from the left to right side of the PCM container whereas the solidification Front moves from right to the left along the axial distances in the PCM container. The results indicate that natural convection dominates the Melting process in the liquid phase due to buoyancy effects. On the other hand, the solidification process is dominated by conduction. The flow rate and inlet temperature of the HTF in the experiment range has a significant effect on the phase change processes. The results also indicate that the heat transfer coefficient between the HTF and the PCM was affected by the Reynolds number more during the Melting process than during the solidification process. Heat flow rate during the Melting and solidification process increased by 25% and 11%, respectively, in the case of increase or decrease by 2 °C of the inlet HTF temperature. The results of this study show that by increasing the inlet water temperature from 70 °C to 74 °C, total Melting time can be decreased by 31%.

  • heat transfer characteristics in latent heat storage system using paraffin wax
    Journal of Mechanical Science and Technology, 2012
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh
    Abstract:

    An energy storage system has been designed to study the heat transfer characteristics of paraffin wax during Melting and solidification processes in a vertical annulus energy storage system. In the experimental study, three important issues are focused. The first one is temperature distribution in the phase change material (PCM) during the phase change processes. The second one is the thermal characteristics of the paraffin wax, which includes total Melting and total solidification times, the nature of heat transfer phenomena in melted and solidified PCM and the effect of Reynolds number as inlet heat transfer fluid (HTF) conditions on the heat transfer parameters. The final one is to calculate heat transfer coefficient and effectiveness during solidification process. The experimental results proved that the PCM melts and solidifies congruently, and the Melting Front moved from the top to the bottom of the PCM container whereas the solidification Front moved from bottom to the top along the axial distances in the PCM container. Experiment has been performed for different water flow rates at constant inlet temperature of heat transfer fluid for recovery and use of heat. Time-based variations of the temperature distributions were explained from the results of observations of Melting and solidification curves. Charging and discharging processes were carried out. Heat transfer characteristics were studied.

  • Heat transfer characteristics in latent heat storage system using paraffin wax
    Journal of Mechanical Science and Technology, 2012
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh
    Abstract:

    An energy storage system has been designed to study the heat transfer characteristics of paraffin wax during Melting and solidification processes in a vertical annulus energy storage system. In the experimental study, three important issues are focused. The first one is temperature distribution in the phase change material (PCM) during the phase change processes. The second one is the thermal characteristics of the paraffin wax, which includes total Melting and total solidification times, the nature of heat transfer phenomena in melted and solidified PCM and the effect of Reynolds number as inlet heat transfer fluid (HTF) conditions on the heat transfer parameters. The final one is to calculate heat transfer coefficient and effectiveness during solidification process. The experimental results proved that the PCM melts and solidifies congruently, and the Melting Front moved from the top to the bottom of the PCM container whereas the solidification Front moved from bottom to the top along the axial distances in the PCM container. Experiment has been performed for different water flow rates at constant inlet temperature of heat transfer fluid for recovery and use of heat. Time-based variations of the temperature distributions were explained from the results of observations of Melting and solidification curves. Charging and discharging processes were carried out. Heat transfer characteristics were studied.

S. Suresh - One of the best experts on this subject based on the ideXlab platform.

  • an experimental study on heat transfer characteristics of paraffin wax in horizontal double pipe heat latent heat storage unit
    Journal of The Taiwan Institute of Chemical Engineers, 2014
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh, S Jegadheeswaran
    Abstract:

    Abstract An experimental study is conducted to investigate the Melting and solidification processes of paraffin wax as a phase change material (PCM) in horizontal double pipe heat latent heat storage unit. The present work on phase change process includes study of temperature variations along the axial distances in PCM, determination of heat transfer coefficient as well as the heat flow rate. A series of experiments was conducted to investigate the effect of increasing the inlet temperature and the mass flow rate of the heat transfer fluid (HTF) both on the charging and discharging processes of the PCM. The experimental results show that the PCM melts and solidifies congruently, and the Melting Front moves from the left to right side of the PCM container whereas the solidification Front moves from right to the left along the axial distances in the PCM container. The results indicate that natural convection dominates the Melting process in the liquid phase due to buoyancy effects. On the other hand, the solidification process is dominated by conduction. The flow rate and inlet temperature of the HTF in the experiment range has a significant effect on the phase change processes. The results also indicate that the heat transfer coefficient between the HTF and the PCM was affected by the Reynolds number more during the Melting process than during the solidification process. Heat flow rate during the Melting and solidification process increased by 25% and 11%, respectively, in the case of increase or decrease by 2 °C of the inlet HTF temperature. The results of this study show that by increasing the inlet water temperature from 70 °C to 74 °C, total Melting time can be decreased by 31%.

  • heat transfer characteristics in latent heat storage system using paraffin wax
    Journal of Mechanical Science and Technology, 2012
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh
    Abstract:

    An energy storage system has been designed to study the heat transfer characteristics of paraffin wax during Melting and solidification processes in a vertical annulus energy storage system. In the experimental study, three important issues are focused. The first one is temperature distribution in the phase change material (PCM) during the phase change processes. The second one is the thermal characteristics of the paraffin wax, which includes total Melting and total solidification times, the nature of heat transfer phenomena in melted and solidified PCM and the effect of Reynolds number as inlet heat transfer fluid (HTF) conditions on the heat transfer parameters. The final one is to calculate heat transfer coefficient and effectiveness during solidification process. The experimental results proved that the PCM melts and solidifies congruently, and the Melting Front moved from the top to the bottom of the PCM container whereas the solidification Front moved from bottom to the top along the axial distances in the PCM container. Experiment has been performed for different water flow rates at constant inlet temperature of heat transfer fluid for recovery and use of heat. Time-based variations of the temperature distributions were explained from the results of observations of Melting and solidification curves. Charging and discharging processes were carried out. Heat transfer characteristics were studied.

  • Heat transfer characteristics in latent heat storage system using paraffin wax
    Journal of Mechanical Science and Technology, 2012
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh
    Abstract:

    An energy storage system has been designed to study the heat transfer characteristics of paraffin wax during Melting and solidification processes in a vertical annulus energy storage system. In the experimental study, three important issues are focused. The first one is temperature distribution in the phase change material (PCM) during the phase change processes. The second one is the thermal characteristics of the paraffin wax, which includes total Melting and total solidification times, the nature of heat transfer phenomena in melted and solidified PCM and the effect of Reynolds number as inlet heat transfer fluid (HTF) conditions on the heat transfer parameters. The final one is to calculate heat transfer coefficient and effectiveness during solidification process. The experimental results proved that the PCM melts and solidifies congruently, and the Melting Front moved from the top to the bottom of the PCM container whereas the solidification Front moved from bottom to the top along the axial distances in the PCM container. Experiment has been performed for different water flow rates at constant inlet temperature of heat transfer fluid for recovery and use of heat. Time-based variations of the temperature distributions were explained from the results of observations of Melting and solidification curves. Charging and discharging processes were carried out. Heat transfer characteristics were studied.

Vittorio Verda - One of the best experts on this subject based on the ideXlab platform.

  • Melting of pcm in a thermal energy storage unit numerical investigation and effect of nanoparticle enhancement
    International Journal of Energy Research, 2013
    Co-Authors: Adriano Sciacovelli, Francesco Colella, Vittorio Verda
    Abstract:

    SUMMARY The present paper describes the analysis of the Melting process in a single vertical shell-and-tube latent heat thermal energy storage (LHTES), unit and it is directed at understanding the thermal performance of the system. The study is realized using a computational fluid-dynamic (CFD) model that takes into account of the phase-change phenomenon by means of the enthalpy method. Fluid flow is fully resolved in the liquid phase-change material (PCM) in order to elucidate the role of natural convection. The unsteady evolution of the Melting Front and the velocity and temperature fields is detailed. Temperature profiles are analyzed and compared with experimental data available in the literature. Other relevant quantities are also monitored, including energy stored and heat flux exchanged between PCM and HTF. The results demonstrate that natural convection within PCM and inlet HTF temperature significantly affects the phase-change process. Thermal enhancement through the dispersion of highly conductive nanoparticles in the base PCM is considered in the second part of the paper. Thermal behavior of the LHTES unit charged with nano-enhanced PCM is numerically analyzed and compared with the original system configuration. Due to increase of thermal conductivity, augmented thermal performance is observed: Melting time is reduced of 15% when nano-enhanced PCM with particle volume fraction of 4% is adopted. Similar improvements of the heat transfer rate are also detected. Copyright © 2012 John Wiley & Sons, Ltd.

M Konczykowski - One of the best experts on this subject based on the ideXlab platform.

  • Vortex-lattice Melting Front in thin superconductors with pinning
    Physical Review B: Condensed Matter and Materials Physics, 2004
    Co-Authors: M V Indenbom, C J Van Der Beek, E. H. Brandt, M Konczykowski
    Abstract:

    Magneto-optical observations of a second flux Front, which occurs at the second peak in the magnetization of Bi2Sr2CaCu2Ox single crystals related to the known first-order "vortex-lattice Melting," are reconsidered. We show that, in thin samples, electrodynamics necessarily leads to an extended region in which the magnetic induction adopts a nearly constant value close to that at which the phase transition occurs at thermal equilibrium. In this region a dynamical phase mixture of vortex "solid" and "liquid" should exist. Interestingly, the observed second flux Front does not mark the "Melting" Front, as it was naively interpreted earlier, but indicates the disappearance of the last "solid droplets".

  • vortex Melting Front in thin superconductors with pinning
    arXiv: Superconductivity, 2002
    Co-Authors: M V Indenbom, E H Brandt, C J Van Der Beek, M Konczykowski
    Abstract:

    Magneto-optical observations of a second flux Front, which occurs at the second peak in the magnetization of Bi_2 Sr_2 CaCu_2 O_x single crystals related to the known first order ``vortex-lattice Melting'', are reconsidered. We show that, in thin samples, electrodynamics necessarily leads to an extended region in which the magnetic induction adopts a nearly constant value close to that at which the phase transition occurs at thermal equilibrium. In this region a dynamical phase mixture of vortex ``solid'' and ``liquid'' should exist. Interestingly, the observed second flux Front does not mark the ``Melting'' Front, as it was naively interpreted earlier, but indicates the disappearance of the last ``solid droplets''.

S Jegadheeswaran - One of the best experts on this subject based on the ideXlab platform.

  • an experimental study on heat transfer characteristics of paraffin wax in horizontal double pipe heat latent heat storage unit
    Journal of The Taiwan Institute of Chemical Engineers, 2014
    Co-Authors: Stella P. Jesumathy, M. Udayakumar, S. Suresh, S Jegadheeswaran
    Abstract:

    Abstract An experimental study is conducted to investigate the Melting and solidification processes of paraffin wax as a phase change material (PCM) in horizontal double pipe heat latent heat storage unit. The present work on phase change process includes study of temperature variations along the axial distances in PCM, determination of heat transfer coefficient as well as the heat flow rate. A series of experiments was conducted to investigate the effect of increasing the inlet temperature and the mass flow rate of the heat transfer fluid (HTF) both on the charging and discharging processes of the PCM. The experimental results show that the PCM melts and solidifies congruently, and the Melting Front moves from the left to right side of the PCM container whereas the solidification Front moves from right to the left along the axial distances in the PCM container. The results indicate that natural convection dominates the Melting process in the liquid phase due to buoyancy effects. On the other hand, the solidification process is dominated by conduction. The flow rate and inlet temperature of the HTF in the experiment range has a significant effect on the phase change processes. The results also indicate that the heat transfer coefficient between the HTF and the PCM was affected by the Reynolds number more during the Melting process than during the solidification process. Heat flow rate during the Melting and solidification process increased by 25% and 11%, respectively, in the case of increase or decrease by 2 °C of the inlet HTF temperature. The results of this study show that by increasing the inlet water temperature from 70 °C to 74 °C, total Melting time can be decreased by 31%.