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Click to edit Master title style Simulation of Co-generation
system with a Molten Carbonate Fuel cell
Student: Niccolò Elia Sovico
Advisor: William A. Ryan, PhD.
1
Overview
n What is a Fuel Cell? Electrochemical system that converts chemical
energy into electric energy
2
NATURAL GAS
HEAT
ELECTRICITY
No combustion Low emissions
The fuel cells of the simulations
Molten carbonate fuel cells
3
NATURAL GAS
100% LOSSES
ELECTRICITY
HEAT
47%
26%
27%
Simulation 1 Simulation 2 Simulation 3 Simulation 4
300 kW 2x300 kW 3x300 kW 1400 kW
Simulation 4: 1400 kWel
4
Exhaust temperature cooled to (°F)
Energy available to be recovered (MMBTU/h)
600 0,6
400 1,6
200 2,7
100 4,9
PLA
NT
Simulation 4: 1400 kWel
5
400
600
800
1000
1200
1400
1600
0 2 4 6 8 10 12 14 16 18 20
Pow
er [
kWe
l an
d k
Wth
]
Operating years
ELECTRICAL POWER AND EXHAUST HEAT
Electric power Normalized electric power Exhaust heat Exhaust heat normalized
STA
CKS
6
y = -1E-07x2 + 0.0022x + 0.0027 R² = 1
1.3
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
600.0 700.0 800.0 900.0 1000.0 1100.0 1200.0 1300.0 1400.0
Re
co
vera
ble
He
at
(MM
BTU
/h)
Electrical power (kWel)
Heat recovered and partial load
Experimental Points
Poly. (Experimental Points)
y = -7E-21x2 + 1E-05x + 0.4317 R² = 1
43.6%
43.8%
44.0%
44.2%
44.4%
44.6%
600.0 700.0 800.0 900.0 1000.0 1100.0 1200.0 1300.0 1400.0
Ele
ctr
ica
l eff
icie
nc
y
Electrical power (kWel)
Electrical efficiency and partial load
Experimental points
Poly. (Experimental points)
Experimental curve
Interpolation
Equation
ALGORITHM
CU
RVES
Simulation 4: 1400 kWel
Simulation 4: 1400 kWel
7
0
500
1000
1500
2000
0 1000 2000 3000 4000 5000 6000 7000 8000
ELEC
TRIC
EN
ERG
Y [k
We
l]
Hours/year
CHRONOLOGICAL ELECTRICITY USAGE AND FUEL CELL PRODUCTION
96% of electric energy comes from the Fuel Cell
ELEC
TRIC
EN
ERG
Y
Simulation 4: 1400 kWel
8
0
2
4
6
8
10
12
14
16 1
304
607
910
1213
15
16
1819
21
22
2425
27
28
3031
33
34
3637
39
40
4243
45
46
4849
51
52
5455
57
58
6061
63
64
6667
69
70
7273
75
76
7879
81
82
8485
He
at
[MM
Btu
]
hours
HEATING LOAD, RECOVERED AND WASTED
51% of the heat demand comes from the Fuel Cell
HEA
T
9
Simulation 4: 1400 kWel
-6
-5
-4
-3
-2
-1
0
1
2
3
4
0 1000 2000 3000 4000 5000 6000 7000 8000
ELEC
TRIC
PO
WER
[kW
/min
]
Hours/year
CHRONOLOGICAL ELECTRICITY RAMP UP AND DOWN
MAXIMUM RAMP ALLOWED: 2.4 kW/
min
RAMP UP EXCEED 63 times/year
RAMP DOWN EXCEED 67 times/year
RA
MP
10
Simulation 4: 1400 kWel R
AM
P
n These fuel cells have been designed to work at full load
n A variation of electrical output power means a variation of the operating temperature
n The stacks and the fuel cell components can be damaged if the operating temperature change too quickly
This fuel cell cannot work under such conditions
Other sizes
11
RES
ULT
S
Fuel cell / other sources
25% 16%
75% 84%
0 Electricity Heat Wasted heat
SIMULATION 1: 300 kW
50% 32% 0.2%
50% 68%
Electricity Heat Wasted heat
SIMULATION 2: 2x300 kW
74% 45% 7%
26% 55%
Electricity Heat Wasted heat
SIMULATION 3: 3x300 kW
96%
51% 23%
4%
49%
Electricity Heat Wasted heat
SIMULATION 4: 1400 kW
Other sizes
12
1st 2nd 3rd 4th 300 kW
300 kW
300 kW
300 kW
300 kW
300 kW
1400 kW
Hours of operation 8760 8760 8760 8760 8760 8760 8760 Operation at full load 8760 8760 8760 8760 8760 7101 1603 Time at full load (%) 100% 100% 100% 100% 100% 81% 18%
N° times with ramp up over 2.4 kW/min 0 0 0 0 0 0 63
N° times with ramp down over 2.4 kW/min 0 0 0 0 0 0 67
RES
ULT
S
13
Ramp up and down 3rd Fuel Cell
RA
MP
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
4.00
0 1000 2000 3000 4000 5000 6000 7000 8000
ELEC
TRIC
PO
WER
[kW
/min
]
hours
CHRONOLOGICAL ELECTRICITY RAMP UP AND DOWN
MAXIMUM RAMP ALLOWED: 2.4 kW/
min
RAMP UP EXCEED 0 times/year
RAMP DOWN EXCEED 0 times/year
Other sizes
14
ELECTRIC ENERGY
[MWh/year]
HEAT [MMBTU/year]
HEAT WASTED [MMBTU/year]
FUEL CONSUMPTION [MMBTU/year]
ηCHP
CO2 EMISSIONS
[t/year]
CO2 REDUCTION
[%]
Baseload 10,015 31,001 - 49,363 - 25,284 -
1x300 kW 2,488 5,003 0 19,098 71% 20,753 18%
2x300 kW 4,976 9,986 21 38,203 71% 16,223 36%
3x300 kW 7,378 13,815 1,035 56,634 69% 11,943 53%
1400 kW 9,622 15,904 3,658 74,121 66% 8,092 68%
Conclusions and Future Plans
n The 1400 kW Fuel Cell gives the best results with the nearly all covered energy demand of the building but suffers from instability due to ramps
n The best compromise is the 3x300 kW. This system
does not suffer from instability and gives satisfying results
n Next step: Water thermal storage in order to
decrease the amount of wasted energy
15
OV
ERV
IEW
References and Acknowledgements
n Direct Fuel Cell, Application Guide, April 2015 n IEA, International Status of Molten Carbonate
Fuel Cell Technology, 2015 n Ryan Carter, Fuel Cell Power Plants, 2015 n Grace Pededrsen, Modeling Combined Heat
and Power in eQuest n ANSI/ASHRAE Standard 105-2014, Standard
Methods of Determining, Expressing, and Comparing Building Energy Performance and Greenhouse Gas Emissions
16
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