Energy Model Pemfc Ntedd Hcmv 16 Dec 2008

7/29/2019 Energy Model Pemfc Ntedd Hcmv 16 Dec 2008

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Stphan Astier, 11/2008

Fuel CellsEnergy Modelling

Bond Graph


Fuel cells

SOFC Stack

Stack PEMFC(1)

Works at 80C

SOFC Stack

at high

temprature

> 700 C

1 cell delivers very low voltage (0.7V)

serie connexion of mise en srie de Ns cells (Ns100) STACK

membraneBipolar plate


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AFC

PEMFC

PAFC

MCFC

SOFC

70-100C

70-100C

150-210C

600-800C

850-1100C

basses T

> 550C

OH-

CO32-

O22-

H+

alcalin

polymre

acidephosphorique

carbonate fondu

oxyde solide

< 200C

hautesT

H2

H2

H2

H2

H2O

H2O

H2OCO2

O2

O2

O2

O2

H2O

CO2

H2, H2O, CO2

Fuel : H2, (+C02 si MCFC)

O2, N2, H2O,

CO2

OXYDANT: O2, (+N2 si air) (+C02 si MCFC)

e-

FC name

Electrolyte Charges nature

Different types

of fuel cells

Temprature

+ Cogeneration


PEM Fuel CELL

Electricity

heatH2 + 1/2 02 H20

inverse electrolysis

water

Efficiency > 50 %

Show video

+


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Diffusion losses

Activation losses

Conduction losses

Electric

energyElectrochemical conversionChemical

energy

Electric

generator

or receptor

External environment = chemical and thermal energy stored

External

storings

Air,

oxygen

Thermal

use

Internal

storings

Flux of matter

(oxider, reductor, electrolyte)

Entropy fluxes

Thermal flux

2 internal storage

Electric double layer

flux electric charges

Electrochemical

component

Internal thermal storage

Energy modelling of electrochemical device


Energy appr oachEnergy appr oach

Bond Graph principlesBond Graph principles

Energy exchanges within a system are described by bonds which reEnergy exchanges within a system are described by bonds which represent power exchanges.present power exchanges.

eeenergy object11

energy object

22ff

eeenergy object11

energy object

22ff

EffortEffort eeand flowand flowffhave different interpretations in the different fields of physihave different interpretations in the different fields of physics.cs.

ds/dt: Entropy flow (J.K-1.s-1)T: Temperature (K)Thermal

dq/dt: Volume flow (m3.s-1)P: Pressure (Pa)Hydraulic

dn/dt: Molar flow (mol.s-1): Chemical potential (J.mol-1)Chemical

V: Velocity (m.s-1)F: Force (N)Mechanical

i: Current (A)v: Voltage (V)Electrical

f: flow (unit)e: Effort (unit)System

The causal bar indicates the effort direction.The causal bar indicates the effort direction.

p = e . f power


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Bond Graph elementsBond Graph elements

Only a limited number of elements are necessary to describe theOnly a limited number of elements are necessary to describe the majority of systems:majority of systems:

An elementAn element RSRS (entropy production) can be used for coupling to a thermal part of the model.can be used for coupling to a thermal part of the model.

Environment

Flow source

SSff

EnvironmentEffort source

SSee

Potential storage

Capacitance

CC: c

Inertial storage

Inductance

II: i

Dissipation

Friction

Resistance

RR: r

Equation without causalityRepresentsElement

0 rfe

0dt

dfie

0dt

decf

cste

cstf



Bond Graph junctionsBond Graph junctions

The exchanges between several elements or different fields of phThe exchanges between several elements or different fields of physicsysics

are implemented through junctions:are implemented through junctions:

GyratorGY

TransformerTF

Equality of efforts0

Equality of flows1

EquationRepresentsJunction

i

ie 0

i

if 0

1221 , rffree

1221 , rferfe

Causal rules:Causal rules:

only one element can fix the flow through a 1only one element can fix the flow through a 1 --junction ;junction ;

only one element can fix the effort through a 0only one element can fix the effort through a 0--junction.junction.


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EE: battery open: battery open--circuit voltagecircuit voltage

Electrochemical conversion and energy storageElectrochemical conversion and energy storage

Electrochemical conversionElectrochemical conversion

--G (J .molG (J .mol--11))

J (mol.sJ (mol.s--11))

E (V)E (V)

I (A)I (A)TFTF

Chemical fieldChemical field Electrical fieldElectrical field

GG: free enthalpy variation: free enthalpy variation

II: current in the battery: current in the battery

JJ: molar flow of lithium ions: molar flow of lithium ions

nn: number of lithium ions moles exchanged for one mole of electro: number of lithium ions moles exchanged for one mole of electrons (n=1)ns (n=1)

FF: Faraday constant: Faraday constant

nF

GE

JnFI

nF


Electricity

Fuel Cell

ElectrolyserH2

H2

H2O2

O2

O2

Heat

Fuel Cell

ElectrolyserH2

H2

H2O2

O2

O2

Heat

H2

O2

H2

O

HEAT

Principle of a H2/O2 Regenerative Fuel Cell RFC or URFC (Unitized )

Reversible eco-fuel / electricit y storage systems

System equivalent to a battery but decoupling ENERGY and POWER

H2 / O2 but also many other redox couples

(redox flow batteries, metal air fuel cells)


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Li t h iumLi t h ium--ion batt ery operat ion pr incip leion batt ery operat ion pr incip le

Elect rochemical pr ocessElect rochemical pr ocess

ionsLi ee--

LoadLoadII

zezLiH'LiH' LiHzezLiH

H'material

Insertion

Hmaterial

Insertion

material

conductor

Li

ionsLi ee--

LoadLoadIIII

zezLiH'LiH' LiHzezLiH

H'material

Insertion

Hmaterial

Insertion

material

conductor

Li


Li t h iumLi t h ium--ion batt ery modelion bat t ery model

Electrochemical conversion and energy storageElectrochemical conversion and energy storage

Energy storageEnergy storage

GG: free enthalpy variation: free enthalpy variation

GG00: reference free enthalpy variation: reference free enthalpy variation

GGstoragestorage: available amount of chemical stored energy: available amount of chemical stored energy

--G (J .molG (J .mol--11))


E (V)E (V)

I (A)I (A)TFTF11

--GG00 (J .mol(J .mol--11))


J(mol.s

J(mol.s--11))

--GG

storage

storage

(J.mol

(J.mol--11))

CCstoragestorage

--GG00nF

storage

0GGG


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Li t h iumLi th ium--ion batt ery modelion batt ery model

Activation and doubleActivation and double--layer phenomenalayer phenomena

Activation phenomenonActivation phenomenon

f

actact

IR

RRactact: linear activation resistance: linear activation resistance

actact: voltage drop due to activation phenomenon: voltage drop due to activation phenomenon

IIff: faradic current: faradic current

Li

Li

Li

Li

e

e

e

e

I

fI

dlI

Electrochemicaldouble-layer

Reactive process

Double layer capacitor

ElectrolyteElectrode

DoubleDouble--layer phenomenonlayer phenomenon

CCdldl


Proprits compares des moyens de stockage


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Proprits compares des moyens de stockage


Electricity - hydrogen reversible transformation,

two energy carriers with complementary properties

Electricity

(Solare, )

Flux carrier

Hydrogen

energy

Stock carrier

Electrolyser

I (A)

V (volt)

210,5 1,5

I (A)

Fuel cell

HYDROGEN + OXYGEN

Electrolyser

Fuel Cell

WATER + ELECTRICITY + HEAT HYDROGEN + OXYGEN

Electrolyser

Fuel Cell

WATER + ELECTRICITY + HEAT HYDROGEN + OXYGEN

Electrolyser

Fuel Cell

WATER + ELECTRICITY + HEAT


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Thierry ALLEAU



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Thierry ALLEAU


Thierry ALLEAU


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Centrale 250 kW PEM

Ballard Power Systems

Centrale domestique

7 kW PEM Plug Power

Stationary

Electricity

and

Heat

Cogeneration



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THE HYDROGENE FUEL

What sources of hydrogen ?

What storage devices and tanks ?

What specifical energies ?

A stock energy carrier

stored in a tank as gazoline

Energies spcifiques des combustibles

Meilleurs accumulateurs

actuels ( Li-ion)

150 Wh/kg

Essence

10 000 Wh/kg

Hydrogne

30 000 Wh/kg

Uranium

116 106 Wh/kg


H2gaz300

bars

H2gaz700

bars

H2liquide

Gaznat200

bars

Gaznatliqu

Mthanol

Essence

S

0

5

1 0

1 52 0

2 5

3 0

3 5

Specific energies of hydrogen storage devices

Energby volume

Energy by mass


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Thierry ALLEAU


Thierry ALLEAU


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A training device for a future power chain

Solar energy, Hydrogen, Electricity

Photographie NASA Aerovironment 2002

Energy Model Pemfc Ntedd Hcmv 16 Dec 2008

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Transcript of Energy Model Pemfc Ntedd Hcmv 16 Dec 2008