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