The Experts below are selected from a list of 24924 Experts worldwide ranked by ideXlab platform

Eetong Pak - One of the best experts on this subject based on the ideXlab platform.

  • theoretical model of the Charging Process for stratified thermal storage tanks
    Solar Energy, 1993
    Co-Authors: Hoseon Yoo, Eetong Pak
    Abstract:

    Abstract In order to provide an upper limit of the performance for stratified thermal storage tanks, a theoretical model of the Charging Process is studied. First, by introduction of reasonable assumptions in addition to the perfect piston flow, an idealized model is developed. Governing equations derived from the model appear to be characterized by the only parameter, Peclet number. Application of the Laplace transform technique to the equations results in a simple closed-from solution for the transient temperature distribution. The model is validated by examining a distinction from a simpler one which is heat conduction between two semi-infinite regions in contact with a moving interface. Temperature profiles for representative cases as well as the effect of the Peclet number on them are illustrated and discussed. Also, the storage efficiency is analytically expressed in terms of the Peclet number. The efficiency by the present model presents similar trends, but is smaller in value in comparison to that by the semi-infinite case. Consequently, the feasible range of the storage efficiency by the present model, which is the difference between the upper and lower limits of the efficiency, becomes more specific. For the convenience of the usage, a simple correlation of the efficiency is proposed as a function of the Peclet number.

Younggy Shin - One of the best experts on this subject based on the ideXlab platform.

  • integral approximate solution for the Charging Process in stratified thermal storage tanks
    Solar Energy, 2011
    Co-Authors: Jae Dong Chung, Younggy Shin
    Abstract:

    Abstract This paper presents the approximate integral solutions to the one-dimensional model describing the Charging Process of stratified thermal storage tanks with fluid mixing at the inlet. The temperature is assumed to be a form of the Fermi–Dirac distribution function, which can be separated into two sets of cubic polynomials for the hot and cold sides of the thermal boundary layers. The proposed approximate integral solutions are compared with previous works on approximate analytic solutions and show reasonable agreement. This approach, however, benefits from reduced mathematical complexity as compared with the complicated solution form and unstable convergence of the series solution found in the previous analytic solutions. For the ideal case of no fluid mixing at the inlet, the thermocline thickness is proportional to the square root of time and reversely proportional to the flow rate. However, if the fluid is mixed perfectly in the region near inlet, the thermocline thickness could be thicker as the flow rate increases because of the increased mixing region caused by promoted flow mixing in this region. Thus the optimal flow rate depends on the relationship between the flow rate and the size of the mixing region.

Hoseon Yoo - One of the best experts on this subject based on the ideXlab platform.

  • theoretical model of the Charging Process for stratified thermal storage tanks
    Solar Energy, 1993
    Co-Authors: Hoseon Yoo, Eetong Pak
    Abstract:

    Abstract In order to provide an upper limit of the performance for stratified thermal storage tanks, a theoretical model of the Charging Process is studied. First, by introduction of reasonable assumptions in addition to the perfect piston flow, an idealized model is developed. Governing equations derived from the model appear to be characterized by the only parameter, Peclet number. Application of the Laplace transform technique to the equations results in a simple closed-from solution for the transient temperature distribution. The model is validated by examining a distinction from a simpler one which is heat conduction between two semi-infinite regions in contact with a moving interface. Temperature profiles for representative cases as well as the effect of the Peclet number on them are illustrated and discussed. Also, the storage efficiency is analytically expressed in terms of the Peclet number. The efficiency by the present model presents similar trends, but is smaller in value in comparison to that by the semi-infinite case. Consequently, the feasible range of the storage efficiency by the present model, which is the difference between the upper and lower limits of the efficiency, becomes more specific. For the convenience of the usage, a simple correlation of the efficiency is proposed as a function of the Peclet number.

Jae Dong Chung - One of the best experts on this subject based on the ideXlab platform.

  • integral approximate solution for the Charging Process in stratified thermal storage tanks
    Solar Energy, 2011
    Co-Authors: Jae Dong Chung, Younggy Shin
    Abstract:

    Abstract This paper presents the approximate integral solutions to the one-dimensional model describing the Charging Process of stratified thermal storage tanks with fluid mixing at the inlet. The temperature is assumed to be a form of the Fermi–Dirac distribution function, which can be separated into two sets of cubic polynomials for the hot and cold sides of the thermal boundary layers. The proposed approximate integral solutions are compared with previous works on approximate analytic solutions and show reasonable agreement. This approach, however, benefits from reduced mathematical complexity as compared with the complicated solution form and unstable convergence of the series solution found in the previous analytic solutions. For the ideal case of no fluid mixing at the inlet, the thermocline thickness is proportional to the square root of time and reversely proportional to the flow rate. However, if the fluid is mixed perfectly in the region near inlet, the thermocline thickness could be thicker as the flow rate increases because of the increased mixing region caused by promoted flow mixing in this region. Thus the optimal flow rate depends on the relationship between the flow rate and the size of the mixing region.

K Hassouni - One of the best experts on this subject based on the ideXlab platform.

  • hydrogen storage by adsorption on activated carbon investigation of the thermal effects during the Charging Process
    International Journal of Hydrogen Energy, 2007
    Co-Authors: Guillaume Hermosillalara, G Momen, Philippe Marty, Le B Neindre, K Hassouni
    Abstract:

    Abstract This paper presents an investigation of the thermal effects during high-pressure Charging of a packed bed hydrogen storage tank. The studied column is packed with activated IRH3 carbon, which has an average surface area of 2600 m 2 g - 1 and is fed with hydrogen or helium from an external high-pressure source. The temperature at six locations in the storage tank and the pressure value at the bottom of the tank are recorded during the Charging stage. Several experiments were carried out to investigate the effect of the initial flow rate on the temperature field in the reservoir and on the duration of the Charging Process. A study of the respective contribution of adsorption and mechanical dissipation effects to the thermal phenomena is done in the case of hydrogen. Experimental results are compared to those obtained with the commercial code Fluent. A fair agreement is found when comparing typical pressure and temperature evolutions during the tank filling.