Non-iterative evaluation of multiphase thermal compliances in bond graphs

The optimal energy efficient operating conditions of a solid oxide fuel cell (SOFC) system needs to be studied by considering the whole closed circuit system rather than a standalone study of the cell efficiency. This study is performed in this paper with the aid of steady state models of the SOFC, the after-burner, and the heat exchanger. For the first time, a comprehensive steady state model of the SOFC is developed and validated. A recursive algorithm with two cascaded optimization loops is applied to maximize the SOFC system efficiency and also to obtain the corresponding cell operating conditions. The developed steady state model aids in the implementation of the optimization procedure. Controlling the SOFC system for maximum efficiency operation for variable loads requires complex control laws. However, it is found that an appropriately chosen constant fuel utilization (FU) operation closely approximates the maximum efficiency operation of the fuel cell in its operating range. This is validated through closed-loop dynamic simulations of a bond graph model of the complete SOFC system. Three different commonly used control strategies and their implications on the energy and exergy efficiencies of the system, as well as their transient load following capabilities, are investigated.

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“…The same factor appears in some other equations (e.g. equations (27) and (48)) in this paper precisely due to the same reason.…”

Section: The Dynamic Equations Of the Sofc Modelsupporting

confidence: 72%

On the rationale behind constant fuel utilization control of solid oxide fuel cells

Vijay

Samantaray

Mukherjee

2008

Proceedings of the Institution of Mechanical Engineers, Part I:

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“…7, the steam quality (X) and steam pressure (P s ) are solved iteratively using bisection method and the result is then used to calculate steam temperature (T s ). An alternative way of modelling storage of mixtures, which does not involve an iterative solution and uses different set of state variables, is given in [18].…”

Section: Bond Graph Model Of Condensermentioning

confidence: 99%

“…Some of the works on bond graph modeling of condensation phenomena assume bulk condensation (similar to cloud formation and its saturation) and base the analysis on the relative humidity [15][16] in the control volume. Other bond graph formulations for storage and transport of two-phase mixtures (water and steam mixture, here) may be consulted in [17][18]. Bond graph representations of film condensation on vertical tubes were developed in [10,[19][20].…”

Section: Introductionmentioning

confidence: 99%

Bond graph model of a vertical U-tube steam condenser coupled with a heat exchanger

Medjaher

Samantaray

Bouamama

2009

Simulation Modelling Practice and Theory

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A simulation model for a vertical U-tube steam condenser in which the condensate is stored at the bottom well is developed in this paper. The U-tubes carrying the coolant are partially submerged in the stored condensate and thus the bottom well acts as a heat exchanger. The storage of hydraulic and thermal energies is represented using a coupled pseudo-bond graph model. Advection effects are modelled by considering reticulated segments of the tubes carrying coolant, over which condensation takes place. The developed model is of intermediate complexity and it is intended for use in observer based real time process supervision, which works by comparing the process behaviour to the reference model outputs. The simulation results obtained from the bond graph model are validated with experimental data from a laboratory setup .

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“…It was used therein to model the heat transfer from the external environment to the inside of a building. Many authors have worked on the bond graph modelling of thermo-fluidic systems: general modelling framework development, thermo-fluid library for process engineering systems (Samantaray et al, 2004), multi-phase systems (Brown, 2002) and applications to steam generators (Ould Bouamama et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Thermal modelling, simulation and experimental validation of heat accumulation in a framed glass cabin

Bera

Dixit

Bhattacharya

et al. 2017

jtam

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The present work concerns prediction of the amount of heat accumulation within the interior of a framed glass cabin and proposes some remedial measures to reduce temperature in the cabin. Various configurations such as double layer glass box filled with static air, static argon gas and flowing argon gas within the space between the two glass-layers are considered to conduct the experiments. Multi-physics bond graph models for these configurations are developed considering thermo-fluidic aspects. The experimental results are compared with the simulations using bond graph models. Though, direct application to a vehicle is not made, without loss of generality, the modelling and experimental procedure can be extended to analyze the heat accumulation inside a vehicle cabin when the vehicle is parked under direct sunlight.

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Non-iterative evaluation of multiphase thermal compliances in bond graphs

Cited by 7 publications

References 5 publications

On the rationale behind constant fuel utilization control of solid oxide fuel cells

On the rationale behind constant fuel utilization control of solid oxide fuel cells

Bond graph model of a vertical U-tube steam condenser coupled with a heat exchanger

Thermal modelling, simulation and experimental validation of heat accumulation in a framed glass cabin

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