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Reinout Heijungs - One of the best experts on this subject based on the ideXlab platform.

  • life cycle assessment for Energy Analysis and management
    Applied Energy, 2007
    Co-Authors: Helias Udo A De Haes, Reinout Heijungs
    Abstract:

    Life-cycle assessment (LCA) is a form of chain Analysis in which structural pathways in the economic system are delineated and connected to environmental problems. As such, it can be seen as an extension of, or a complement to, Energy Analysis. The main developments over the past 30 years are sketched in a perspective that puts an emphasis on standardization and scientific consensus creation. We end with a logical next development: a closer cooperation and harmonization with the domain of Energy Analysis, and an expected growing interest from the Energy-application side.

Rangan Banerjee - One of the best experts on this subject based on the ideXlab platform.

  • Net Energy Analysis of hydrogen storage options
    International Journal of Hydrogen Energy, 2005
    Co-Authors: A. Sarkar, Rangan Banerjee
    Abstract:

    Abstract Hydrogen storage is critical for developing viable hydrogen vehicles. This paper compares compressed hydrogen, cryogenic hydrogen and metal hydride (Mg and FeTi) options using net Energy Analysis. A simulation of an Indian vehicle with an urban drive cycle using a fuel cell stack is carried out to determine the total hydrogen required per km of travel. Net Energy Analysis is carried out considering the Energy requirements of the storage device and the Energy required to produce and store the hydrogen. From net Energy Analysis compressed hydrogen is the preferred option. The direct Energy requirement is more than 55% for magnesium hydride as compared to compressed hydrogen due to the combined effect of increase in weight and higher heat of desorption. In addition to volumetric and gravimetric storage density, it is felt that net Energy Analysis should be also included as an additional criteria for evaluating any storage option. For metal hydride storage the net Energy required to produce the tank should be minimum. This could be used as a selection criterion to design an optimum metal hydride storage. The performance of other materials like porous carbon, carbon nanotubes and hybrids can be evaluated using net Energy Analysis.

Nicolas Totaro - One of the best experts on this subject based on the ideXlab platform.

  • STATISTICAL Energy Analysis AND DIFFUSE FIELD
    2019
    Co-Authors: Alain Le Bot, Nicolas Totaro, Laurent Maxit
    Abstract:

    Statistical Energy Analysis (SEA) is a statistical theory of sound and vibration based on an analogy with thermodynamics. The main relationship of statistical Energy Analysis, the so-called coupling power proportionality, is intimately linked with the establishment of a diffuse vibration field in subsystems. In this study, we explore the conditions under which a diffuse field is enforced. We show that when the subsystem is excited by a point force, a low damping, a high frequency but also a ergodic billiard geometry are required conditions. Then, the Energy exchange between two weakly coupled subsystems is proportional to the difference of vibrational energies. But when the field is not diffuse, the exchange of Energy does not generally follow this proportionality. Numerical simulations are provided to support the discussion.

  • Statistical Energy Analysis, assumptions and validity
    2017
    Co-Authors: Alain Le Bot, Nicolas Totaro, Thibault Lafont
    Abstract:

    This study outlines the question of validity of statistical Energy Analysis with regard to its assumptions. We discuss the necessity of four assumptions: rain-on-the-roof excitation, weak coupling, large number of modes and light damping. We show that when all of these assumptions are satisfied, statistical Energy Analysis provides a satisfactory result but when one of these assumptions is violated, statistical Energy Analysis prediction presents a discrepancy compared to a reference calculation. The discussion is illustrated with a simple example of coupled plates.

  • MODal Energy Analysis
    2013
    Co-Authors: Nicolas Totaro, Jean-louis Guyader
    Abstract:

    The Modal Energy Analysis presented in this paper is a method to predict Energy exchanges between vibro-acoustic subsystems. As well-known methods like Statistical Energy Analysis (SEA) or Statistical modal Energy distribution Analysis (SmEdA), the proposed method is based on equations of motion of two coupled oscillators. However, these equations are here solved in narrow band. The net exchanged power between the two coupled oscillators is then proportional to the total energies of oscillators using a pure tone modal coupling loss factor. Extending it to the case of two continuous coupled subsystems (using dual modal formulation), it yields a system of linear equations linking modal injected power to modal energies of subsystems at a particular frequency. In that way, the non-resonant contribution of modes is intrinsically taken into account. In the present paper, the theoretical background of the proposed method will be explained and assumptions and domain of validity will be identified. Finally, numerical simulations on a plate/cavity and a cavity/plate/cavity test case will be addressed. A numerical example of a ribbed plate coupled to a cavity will be also presented.

  • MODal Energy Analysis
    Journal of Sound and Vibration, 2013
    Co-Authors: Nicolas Totaro, Jean-louis Guyader
    Abstract:

    Abstract Energy methods like Statistical Energy Analysis (SEA) or Statistical modal Energy distribution Analysis (SmEdA), based on the well-known equations of two coupled oscillators, are both limited when non-resonant contributions of modes are not negligible (typically in the case of cavity/structure/cavity coupling). In SEA, this non-resonant contribution can be taken into account introducing indirect coupling between subsystems. In SmEdA, the non-resonant contribution is more difficult to estimate as indirect coupling is not allowed. However, this issue can be a matter of importance to compute Transmission Loss (TL) of highly damped structures for example. The present work deals with an Energy method, developed within the framework of SmEdA, which solves the system of equations of two coupled oscillators at pure tone, taking thus intrinsically into account the non-resonant contributions of oscillators. As in SEA or SmEdA, the net exchanged power between two coupled oscillators is proportional to the weighted difference of total energies of oscillators. The expression of a critical coupling strength is also proposed and may be related to classical weak coupling criterion of SEA. Extending equations obtained for two coupled sets of oscillators to the case of two linear continuous subsystems, one can compute easily frequency dependent modal energies of modes, total energies of subsystems, power transmitted between two modes and power dissipated. The theoretical bases and assumptions of the proposed MODal Energy Analysis (MODENA) are first exposed and the case of two coupled oscillators is addressed. Then, plate/cavity and cavity/plate/cavity systems are treated with MODENA and compared to an exact solution. Finally, it is demonstrated that the non-resonant contribution of a highly damped plate is correctly represented by MODENA.

Helias Udo A De Haes - One of the best experts on this subject based on the ideXlab platform.

  • life cycle assessment for Energy Analysis and management
    Applied Energy, 2007
    Co-Authors: Helias Udo A De Haes, Reinout Heijungs
    Abstract:

    Life-cycle assessment (LCA) is a form of chain Analysis in which structural pathways in the economic system are delineated and connected to environmental problems. As such, it can be seen as an extension of, or a complement to, Energy Analysis. The main developments over the past 30 years are sketched in a perspective that puts an emphasis on standardization and scientific consensus creation. We end with a logical next development: a closer cooperation and harmonization with the domain of Energy Analysis, and an expected growing interest from the Energy-application side.

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

  • Net Energy Analysis of hydrogen storage options
    International Journal of Hydrogen Energy, 2005
    Co-Authors: A. Sarkar, Rangan Banerjee
    Abstract:

    Abstract Hydrogen storage is critical for developing viable hydrogen vehicles. This paper compares compressed hydrogen, cryogenic hydrogen and metal hydride (Mg and FeTi) options using net Energy Analysis. A simulation of an Indian vehicle with an urban drive cycle using a fuel cell stack is carried out to determine the total hydrogen required per km of travel. Net Energy Analysis is carried out considering the Energy requirements of the storage device and the Energy required to produce and store the hydrogen. From net Energy Analysis compressed hydrogen is the preferred option. The direct Energy requirement is more than 55% for magnesium hydride as compared to compressed hydrogen due to the combined effect of increase in weight and higher heat of desorption. In addition to volumetric and gravimetric storage density, it is felt that net Energy Analysis should be also included as an additional criteria for evaluating any storage option. For metal hydride storage the net Energy required to produce the tank should be minimum. This could be used as a selection criterion to design an optimum metal hydride storage. The performance of other materials like porous carbon, carbon nanotubes and hybrids can be evaluated using net Energy Analysis.