The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform

Robert Pitz-paal - One of the best experts on this subject based on the ideXlab platform.

  • Advanced Concentrating Thermal Technologies for Power and Process Heat Generation
    2017
    Co-Authors: Robert Pitz-paal
    Abstract:

    Concentrating solar thermal technologies are in a phase of commercial implementation for about 10 years. Up to now parabolic trough systems using synthetic thermal oil as Heat Transfer Medium and a molten salt Heat storage system is the dominating technology in the market. In parallel smaller units to provide process Heat in a decentralized markets are evolving. Solar tower technology using molten salt as Heat Transfer Medium is currently emerging with the promise to reduce the cost for dispatchable power significantly. A variety of other new Heat Transfer fluids with different particular benefits have been developed in the past to enable further cost reductions. This range from new silicon based thermal, oil, direct steam generation, atmospheric air, advanced salt mixtures, liquid metals and ceramic particles. The talk will introduce the different concepts and evaluate the maturity and potential for both centralized power production and decentralized process Heat supply.

  • Modelling and optimization of transient processes in line focusing power plants with single-phase Heat Transfer Medium
    2016
    Co-Authors: Kareem Noureldin, L. M. González-escalada, Tobias Hirsch, Bijan Nouri, Robert Pitz-paal
    Abstract:

    A large number of commercial and research line focusing solar power plants are in operation and under development. Such plants include parabolic trough collectors (PTC) or linear Fresnel using thermal oil or molten salt as the Heat Transfer Medium (HTM). However, the continuously varying and dynamic solar condition represent a big challenge for the plant control in order to optimize its power production and to keep the operation safe. A better understanding of the behaviour of such power plants under transient conditions will help reduce defocusing instances, improve field control, and hence, increase the energy yield and confidence in this new technology. Computational methods are very powerful and cost-effective tools to gain such understanding. However, most simulation models described in literature assume equal mass flow distributions among the parallel loops in the field or totally decouple the flow and thermal conditions. In this paper, a new numerical model to simulate a whole solar field with sing...

  • Heat recovery concept for thermochemical processes using a solid Heat Transfer Medium
    Applied Thermal Engineering, 2014
    Co-Authors: Jan Felinks, Stefan Brendelberger, Martin Roeb, Christian Sattler, Robert Pitz-paal
    Abstract:

    Abstract The solar to fuel efficiency of a thermochemical water or carbon dioxide splitting process based on redox reactions with metal oxides and driven by concentrated solar energy highly depends on the Heat recovery of sensible Heat from the redox material. Today, no system exists that recovers Heat between two redox particles streams at a temperature of about 1400 °C without the risk of an undesired reoxidation of the particles. Furthermore, a counter-current principle is essential to reach satisfactorily high Heat recovery rates. In this work, we introduce a new concept utilizing a solid Heat Transfer Medium in the form of spheres for Heat recovery from particles. The mixing of redox particle and Heat Transfer spheres leads to a high surface area and enables an improved Heat Transfer. An appropriate connection of multiple Heat Transfer stages allows a quasi-counter-current Heat Transfer principle. A performance model of the system determines the Heat recovery rate to be reached by the system.

Hideo Inaba - One of the best experts on this subject based on the ideXlab platform.

  • Heat release characteristics of middle temperature latent Heat storage vessel by means of direct contact Heat exchange method
    TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 1999
    Co-Authors: Hideo Inaba, Akihiko Horibe, Koichi Ozaki, Kazuo Emoto, Hiroyuki Kakiuchi
    Abstract:

    Experiment has been performed of Heat Transfer characteristics of the middle temperature latent Heat storage system of the direct-contact Heat Transfer by using m-E (meso-Erythritol, melting point of 119°C, latent Heat of 375 kJ/kg) droplets as a latent Heat storage material and silicone oil as a Heat Transfer Medium. In the present study the liquid m-E was injected into the Heat tranfer Medium through a circular nozzle. The m-E droplets changed from liquid to solid phase during falling in the Heat Transfer Medium at low temperature. From the measuring results of m-E droplet diameter, falling velocity, and solidification rate, the nondimensional empirical equations of the arithmetic mean diameter of the droplets and falling velocity, the solidification rate and the overall Heat Transfer coefficient were derived as a function of the characteristic arithmetic mean diameter, the terminal velocity, temperature and physical properties.

  • Heat Storage Characteristics of an Inclined Rectangular Heat Storage Vessel Packed with Plate Type of Shape-Stabilized Phase Change Material.
    Transactions of the Japan Society of Mechanical Engineers. B, 1998
    Co-Authors: Hideo Inaba, Ping Tu, Akihiko Horibe, Koichi Ozaki
    Abstract:

    The present study deals with the Heat storage characteristics of the inclined rectangular vessel packed with spape-stabilized paraffin plates as a latent Heat storage material by numerical analysis. It was found that the Heat storage characteristics were remarkedly affected by the inclination angle of the rectangular vessel and the Heat Transfer Medium flow direction, due to the presence of natural convection in the fluid flow channel between the paraffin plates. Numerical results revealed flow patterns, temperature profiles and Heat storage characteristics for various inclination angles, inlet velocities and temperatures of the Heat Transfer Medium fluid, and widths of the fluid flow channel.

  • transient Heat characteristics of a rectangular Heat storage vessel packed with shape stabilized phase change material effect of various factors on Heat release process
    Transactions of the Japan Society of Mechanical Engineers. B, 1996
    Co-Authors: Hideo Inaba, T U Ping
    Abstract:

    Transient Heat release characteristics of a rectangular latent Heat storage vessel packed with shape-stabilized phase change (solid-liquid) material (PCM) are investigated numerically with the finite difference technique. It is found that the Heat release characteristics are greatly affected by the flow direction of the Heat Transfer Medium since natural and forced convections coexist in the Heat storage vessel. It is clarified that the thermal efficiency of the latent Heat storage system is obtained by an upward flow along the vertical PCM for Heat release process The effect of the inlet velocity and the inlet temperature of Heat Transfer Medium and the dimensions of the phase change material on transient Heat release characteristics of the latent Heat storage system are also revealed in the present study.

  • numerical study on transient Heat characteristics of a rectangular latent Heat storage vessel
    Memoirs of the Faculty of the Engineering Okayama University, 1995
    Co-Authors: Hideo Inaba, Koichi Ozaki
    Abstract:

    Transient characteristics of the rectangular latent Heat storage vessel packed with shape-stabilized phase change (solid-liquid) material (PCM) are investigated numerically by solving the governing equations of both the PCM and the Heat Transfer Medium(water) simultaneously as a conjugate problem with the finite difference technique. It's found that the Heat storage characteristics are greatly affected by the flow direction of the Heat Transfer Medium since the natural and forced convection coexists in the Heat storage vessel. That is, it is classified that the effectively thermal efficiency of the latent Heat storage system is obtained by the downflow along vertical PCM for Heat storage process and the upflow for Heat release process. The effect of the inlet velocity of Heat Transfer Medium(water) on transient Heat characteristics of the latent Heat storage system is also revealed in the present study.

Koichi Ozaki - One of the best experts on this subject based on the ideXlab platform.

  • Heat release characteristics of middle temperature latent Heat storage vessel by means of direct contact Heat exchange method
    TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 1999
    Co-Authors: Hideo Inaba, Akihiko Horibe, Koichi Ozaki, Kazuo Emoto, Hiroyuki Kakiuchi
    Abstract:

    Experiment has been performed of Heat Transfer characteristics of the middle temperature latent Heat storage system of the direct-contact Heat Transfer by using m-E (meso-Erythritol, melting point of 119°C, latent Heat of 375 kJ/kg) droplets as a latent Heat storage material and silicone oil as a Heat Transfer Medium. In the present study the liquid m-E was injected into the Heat tranfer Medium through a circular nozzle. The m-E droplets changed from liquid to solid phase during falling in the Heat Transfer Medium at low temperature. From the measuring results of m-E droplet diameter, falling velocity, and solidification rate, the nondimensional empirical equations of the arithmetic mean diameter of the droplets and falling velocity, the solidification rate and the overall Heat Transfer coefficient were derived as a function of the characteristic arithmetic mean diameter, the terminal velocity, temperature and physical properties.

  • Heat Storage Characteristics of an Inclined Rectangular Heat Storage Vessel Packed with Plate Type of Shape-Stabilized Phase Change Material.
    Transactions of the Japan Society of Mechanical Engineers. B, 1998
    Co-Authors: Hideo Inaba, Ping Tu, Akihiko Horibe, Koichi Ozaki
    Abstract:

    The present study deals with the Heat storage characteristics of the inclined rectangular vessel packed with spape-stabilized paraffin plates as a latent Heat storage material by numerical analysis. It was found that the Heat storage characteristics were remarkedly affected by the inclination angle of the rectangular vessel and the Heat Transfer Medium flow direction, due to the presence of natural convection in the fluid flow channel between the paraffin plates. Numerical results revealed flow patterns, temperature profiles and Heat storage characteristics for various inclination angles, inlet velocities and temperatures of the Heat Transfer Medium fluid, and widths of the fluid flow channel.

  • numerical study on transient Heat characteristics of a rectangular latent Heat storage vessel
    Memoirs of the Faculty of the Engineering Okayama University, 1995
    Co-Authors: Hideo Inaba, Koichi Ozaki
    Abstract:

    Transient characteristics of the rectangular latent Heat storage vessel packed with shape-stabilized phase change (solid-liquid) material (PCM) are investigated numerically by solving the governing equations of both the PCM and the Heat Transfer Medium(water) simultaneously as a conjugate problem with the finite difference technique. It's found that the Heat storage characteristics are greatly affected by the flow direction of the Heat Transfer Medium since the natural and forced convection coexists in the Heat storage vessel. That is, it is classified that the effectively thermal efficiency of the latent Heat storage system is obtained by the downflow along vertical PCM for Heat storage process and the upflow for Heat release process. The effect of the inlet velocity of Heat Transfer Medium(water) on transient Heat characteristics of the latent Heat storage system is also revealed in the present study.

Jan Felinks - One of the best experts on this subject based on the ideXlab platform.

  • Heat recovery concept for thermochemical processes using a solid Heat Transfer Medium
    Applied Thermal Engineering, 2014
    Co-Authors: Jan Felinks, Stefan Brendelberger, Martin Roeb, Christian Sattler, Robert Pitz-paal
    Abstract:

    Abstract The solar to fuel efficiency of a thermochemical water or carbon dioxide splitting process based on redox reactions with metal oxides and driven by concentrated solar energy highly depends on the Heat recovery of sensible Heat from the redox material. Today, no system exists that recovers Heat between two redox particles streams at a temperature of about 1400 °C without the risk of an undesired reoxidation of the particles. Furthermore, a counter-current principle is essential to reach satisfactorily high Heat recovery rates. In this work, we introduce a new concept utilizing a solid Heat Transfer Medium in the form of spheres for Heat recovery from particles. The mixing of redox particle and Heat Transfer spheres leads to a high surface area and enables an improved Heat Transfer. An appropriate connection of multiple Heat Transfer stages allows a quasi-counter-current Heat Transfer principle. A performance model of the system determines the Heat recovery rate to be reached by the system.

Jahar Sarkar - One of the best experts on this subject based on the ideXlab platform.

  • Research and development on composite nanofluids as next-generation Heat Transfer Medium
    Journal of Thermal Analysis and Calorimetry, 2019
    Co-Authors: Vivek Kumar, Jahar Sarkar
    Abstract:

    Nanocomposite is a nanotechnology-based multiphase, high-performance composite material having combination of properties, which has been emerged as one of the promising research and development activities. Recently, nanocomposites have shown significant application opportunities for several sectors of biotechnology, engineering, and medical sciences, and its dispersed fluids (composite nanofluids) have gained huge interest and demand in wide area of engineering applications, particularly for Heat Transfer intensification. The main aim of the present review is to summarize the recent advances in nanocomposite-dispersed nanofluids. The synthesized methods, characterization, and applications of nanocomposites as well as the preparation, stability analysis, thermophysical, optical and electrical properties, Heat Transfer and pressure drop characteristics and applications of nanocomposite-dispersed nanofluids are well-grouped and discussed. Present review reveals that the nanocomposite with proper combination of nanomaterials yields superior performance characteristics compared to the individual alone for application in nanofluids, although many related aspects are still unexplored. Hence, the challenges and opportunities for future research are also identified, which will be useful for the newcomers and manufacturers in this field.