Component 82: Fuel Cell

In This Topic

Component 82 : Fuel Cell

Specifications

Line connections
1	Oxidation gas inlet (e.g. air, O2)
2	Off-gas (cathode)
3	Off-gas (anode)
4	Fuel gas inlet
5	Steam inlet(only for old version with reformer)
6	Cooling water inlet
7	Cooling water outlet
8	Generated electrical power

General User Input Values Characteristic Lines Physics Used Displays Example

General

For this component, there has been a complete redesign in Ebsilon Professional Release 6.0. If, for compatibility reasons, it is required to reproduce the results of former calculations, it is possible to switch to the old calculation mode by setting FSPEC = "old mode".

While in the old mode, the reformer was integrated to component 82, the new mode requires a separate modeling of the reformer. For this purpose, you can use component 95 which calculates the chemical equilibrium (instead of a global description by characteristic lines). Therefore, a more detailed consideration is possible.

In the new calculation mode, there is a classification of different types of fuel cells. Use the parameter FSPEC to switch between these types. They are different by the used fuel gas and by the substances that appear at the anode and the cathode. The types implemented in EBSILON^®Professional are PEM, PAFC, MCFC and SOFC.

For all types (in the new calculation mode), it is required to specify the mass flow, the temperature and the pressure of the inlet flows (fuel, oxidation gas and cooling water) and the chemical composition of fuel and oxidation gas. Steam, air or universal fluid may also be used as a cooling medium.
According to the specified fuel cell type, a chemical conversion is calculated. The conversion rates are determined by the specification parameters ECONH2 and ECONCO. The resulting reaction products are distributed to anode and cathode according to the picture above. Unused portions of the fuel gas are added to the anode outlet, unused portions of the oxidation gas are added to the cathode outlet.

The generated electrical powers and the temperature of anode and cathode off-gas are calculated using the specified efficiencies and losses:

electrical efficiency,
cooling efficiency,
cathode off-gas efficiency,
anode efficiency,
loss grade (for other losses, e.g. heat losses)
conversion efficiency DC/AC

For the first five of these quantities, a mass flow dependency can be specified by characteristic lines.

Specification of voltage, frequency and type of current in the component:

There is the option of specifying the voltage (VOLT), frequency (FREQ) and type of current (NPHAS) as the default value in the component.

The flags FVOLT and FFREQ are used to set whether the specification is to be made by the new specification values VOLT and FREQ respectively (0) or externally as a measured values on the electrical line (-1).

User Input Values

FMODE	Calculation mode Like in Parent Profile (Sub Profile option only) Expression =0: GLOBAL =1: Local off-design
FSPEC	Type of fuel cell: Like in Parent Profile (Sub Profile option only) Expression =0: Old mode (including reformer) =1: PEM =2: PAFC =3: MCFC =4: SOFC
ETAEN	Electrical efficiency = QEN/(NCV*M1N)
ETACN	Cooling efficiency = QCN/(NCV*M1N)
ETAON	Cathode off-gas efficiency = QON/(NCV*M1N)
ETALN	Degree of loss = QLOSS/(NCV*M1N)
ETAANN	Anode efficiency
ECONH2	Conversion rate H2
ECONCO	Conversion rate CO
EDCAC	Transformation efficiency DC to AC
FFUEL	Type of fuel (old mode only) Like in Parent Profile (Sub Profile option only) Expression =0: Hydrocarbon =1: Hydrogen
ALAM	Air ratio (air to air stoichiometric, old mode only)
DP12N	Pressure loss between line 1 and 2 (nominal)
DP67N	Pressure loss between line 6 and 7 (nominal)
FVOLT	Flag for the method for specification of voltage Like in Parent Profile (Sub Profile option only) Expression =0: Defined by specification value VOLT =-1: Voltage given externally on electrical outlet
VOLT	Voltage (on electric lines)
FFREQ	Flag for the method for specification of frequency Like in Parent Profile (Sub Profile option only) Expression =0: Use specification value FREQ =-1: Frequency given externally on electrical outlet
FREQ	Generator frequency
NPHAS	Type of current Like in Parent Profile (Sub Profile option only) Expression =0: Direct current =1: One-phase alternating =3: Three-phase alternating
M1N	Air mass flow (nominal)
M4N	Fuel mass flow (nominal)
M6N	Cooling water mass flow (nominal)
V1N	Specific volume of the oxidizer (nominal)
V6N	Specific volume of the cooling water (nominal)

The specification values marked in blue are reference values for the off-design calculations.

Generally, all inputs that are visible are required. But, often default values are provided.

For more information on colour of the input fields and their descriptions see Edit Component\Specification values

For more information on design vs. off-design and nominal values see General\Accept Nominal values

Characteristic Lines

Characteristic line 1: ETAE-characteristic line: ETAE/ETAEN = f (M4/M4N)

     X-axis         1         M4/M4N                     1^st point
                        2          M4/M4N                    2^nd point
                        .
                      N         M4/M4N                    last point

     Y-axis         1          ETAE/ETAEN               1^st point
                        2          ETAE/ETAEN             2^nd point
                        .
                        N         ETAE/ETAEN               last point

Characteristic line 2: ETAC-characteristic line: ETAC/ETACN = f (M4/M4N)

     X-axis          1         M4/M4N                     1^st point
                        2          M4/M4N                    2^nd point
                        .
                      N         M4/M4N                    last point

     Y-axis        1          ETAC/ETACN             1^st point
                        2          ETAC/ETACN             2^nd point
                        .
                        N         ETAC/ETACN             last point

Characteristic line 3: ETAO-characteristic line: ETAO/ETAON = f (M4/M4N)

     X-axis          1         M4/M4N                     1^st point
                        2          M4/M4N                    2^nd point
                        .
                      N         M4/M4N                    last point

     Y-axis          1          ETAO/ETAON           1^st point
                        2          ETAO/ETAON            2^nd point
                        .
                        N         ETAO/ETAON             last point

Characteristic line 4: ETAL-characteristic line: ETAL/ETALN = f (M4/M4N)

     X-axis          1         M4/M4N                     1^st point
                        2          M4/M4N                    2^nd point
                        .
                      N         M4/M4N                    last point

     Y-axis          1          ETAL/ETALN               1^st point
                        2          ETAL/ETALN               2^nd point
                        .
                        N         ETAL/ETALN               last point

Characteristic line 5: ETAAN-characteristic line: ETAA/ETAAN = f (M4/M4N)

     X-axis          1         M4/M4N                     1^st point
                        2          M4/M4N                    2^nd point
                        .
                      N         M4/M4N                    last point

     Y-axis          1          ETAA/ETAAN            1^st point
                        2          ETAA/ETAAN              2^nd point
                        .
                        N         ETAA/ETAAN              last point

Physics Used

Equations

Design case

(Simulation flag:

GLOBAL = Design case

and

FMODE = GLOBAL)

CORE=1

CORC=1

CORO=1

CORL=1

F1 = 1

F6 = 1

Off-design

(Simulation flag:

GLOBAL = Off-design

FMODE = Local Off-design)

CORE = f(M4/M4N) from characteristic line 1

CORC = f(M4/M4N) from characteristic line 2

CORO= f(M4/M4N) from characteristic line 3

CORL = f(M4/M4N) from characteristic line 4

F1 = (M1/M1N ** 2) * (V1/V1N)

F6 = (M6/M6N ** 2) * (V6/V6N)

All cases

QZU = D4*(Hu4+H4)+D1*H1

DQE = ETAEN*CORE*QZU

DQC = ETACN*CORC*QZU

DQO = ETAON*CORO*QZU

DQL = ETALN*CORL*QZU

DQA = QZU-(DQE-DQC-DQO-DQL)

Composition and mass flow line 2:

if FFUEL = Hydrocarbon then

composition owing to hydrogen combustion and DQE+DQO

mass flow owing to hydrogen combustion and DQE+DQO

else

composition owing to hydrogen combustion and DQE+DQO+DQC+DQL

mass flow owing to hydrogen combustion and DQE+DQO+DQC+DQL

endif

Composition line 3:

From combustion calculation line 1/ line 4

minus composition line 2

plus composition line 5

M1M4R = Mass flow ratio line 1/ line 4 from combustion calculation

M1 = M1M4R *M4

M3=M1+M4+M5-M2

DP12 = DP12N* F1

P2 = P1 DP12

P3 = P2

DP67 = DP67N* F6

P7 = P6 DP67

H8 = DQE

H7 = H6+DQC

H2 = DQO/M2

H3 = ((H5-2500.)*M5+DQA)/M3

Component Displays

Display Option 1

Example

Click here >> Component 82 Demo << to load a PAFC fuel cell example.

Click here >> Component 82 PEM << to load a PEM fuel cell example.

Click here >> Component 82 SOFC << to load a SOFC fuel cell example.

Click here >> Component 82 MCFC << to load a MCFC fuel cell example.