2004 usdoe hydrogen, fuel cells & infrastructure technologies … · 2004-06-04 · a u.s....

A U.S. Department of EnergyOffice of Science LaboratoryOperated by The University of Chicago

Argonne National Laboratory

Office of ScienceU.S. Department of Energy

Fuel Cell Systems AnalysisFuel Cell Systems Analysis2004 USDOE Hydrogen, Fuel Cells & Infrastructure Technologies Program ReviewPhiladelphia, PAMay 24-27, 2004

R. K. Ahluwalia, X. Wang, E. Doss, R. Kumar

The submitted manuscript has been created by the University of Chicago as Operator of Argonne National Laboratory (“Argonne”) under Contract No. W-31-109-ENG-38 with the U.S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

This presentation does not contain proprietary or confidential information

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Pioneering Science andTechnology

Office of ScienceU.S. Department

of EnergyHydrogen, Fuel Cells, & Infrastructure Technologies Program

ObjectiveObjectiveDevelop a validated system model and use it to assess design-point, part-load and dynamic performance of automotive fuel cell systems• Support DOE in setting R&D goals and research directions• Establish metrics for gauging progress of R&D activities

A. Compressors/ExpandersC. Fuel Cell Power System

BenchmarkingD. Heat UtilizationH. Start-up Time

I. Fuel Processor Start-up and Transient Operation

M. Fuel Processor SystemIntegration and Efficiency

R. Thermal and Water Mgmt

FY 2004 Budget: $400 K

Technical Barriers Addressed

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ApproachApproach

Develop, document & make available versatile system design and analysis tool• GCtool: Stand-alone code on PC platform• GCtool_ENG: Coupled to PSAT (MATLAB/SIMULINK)

Validate the models against data obtained in laboratory and at Argonne’s Fuel Cell Test Facility

Apply models to issues of current interest• Work with FreedomCAR Technical Teams • Work with DOE contractors as requested by DOE

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Project milestonesProject milestones

08/04Evaluate performance of PEFC systems for combined heat and power

05/04Assess the effect of humidity on high-temperature membrane FC systems

09/04

07/04

03/04

01/04

12/03

Date

Analyze FC systems for hybrid vehicles

Evaluate thermal and water management requirements and subsystem

Establish efficiency targets for membrane based fuel processors

Analyze data taken at ANL’s Fuel Cell Test Facility

Build models for components and systems

Milestone

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Reviewers’ commentsReviewers’ commentsFocus on hydrogen fuel-cell systems• Focus on hydrogen storage options (working with TIAX)• Resolve benefits of high temperature membranes withregard to efficiency, performance and BOP(presentations to Tech Team and HTMWG)

• Plan verification with subsystem and component datafrom contractors (Honeywell/Emprise)

Closer communications with FreedomCAR Fuel Cell and Vehicle Teams• Member of Fuel Cell Tech Team• Participating in hybridization study with Joint Team• Seek OEM validation of model results and proposedtargets (presentation on Start-up Energy Consumption)

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Code development in FY 2004Code development in FY 2004• Dynamic model of enthalpy wheel humidifier• Membrane humidifier model • Dynamic models of catalytic auto-thermal, shift and

PrOx reactors

Enthalpy Wheel Model Simulation Model Validation

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10 20 30 40 50 60Speed, RPM

FC In

let D

P Te

mpe

ratu

re, o C

60 g/s, 2.5 atm

30 g/s, 1.7 atm

37°C

118°C

78°C

170°C

Φ5.6" × 6.5"80 ° C Wet Air

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0 5 10 15 20Axial Node

Des

icca

nt T

empe

ratu

re, o C

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Vapo

r Upt

ake,

%

Wet Dry

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3 4

5

6

1 2 3 4 5 6

1 2 3 4 5 6

80 °C2.3 atm

107 °C2.5 atm

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Validated models against data taken at ANL’s Fuel Validated models against data taken at ANL’s Fuel Cell Test FacilityCell Test FacilityAnalyzed test data for two systems from Nuvera• Series SFAA 1A Fuel Cell System: 10 kWe, gasoline

powered fuel cell system• STAR System: 200 kWt

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100

50 75 100 125 150 175 200Input Thermal Power, kWt

%

Reformer System Efficiency

FPS EfficiencyFuel Utilization

True FPS Efficiency

Major conclusions• Possible to characterize FPS

performance in terms of S/C, O/C and COx selectivity

• True efficiency, which includes LHV of fuel burned in TGC, is a better measure of FPS performance

STAR Performance

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Efficiency of membrane reactorEfficiency of membrane reactor--based fuel processorsbased fuel processors• Why membrane reactors for WGS?

- Eliminate difficult-to-control PrOx reactors- Shrink WGS reactor, simplify lay-out, remove HXs- Not having to deal with CO in PEFC stack is a plus

Process Water

Fuel

Cathode Air

Process Air

Steam Generator

Membrane Reactor

Water

ATR

PEFC Stack

H2

Carrier SteamDemister

HX

Tail Gas Combustor

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Target efficiency needed for HTarget efficiency needed for H22 membrane reactor membrane reactor based FPS can be reduced to 68%based FPS can be reduced to 68%

• 100% H2 recovery not required • FPS will have to operate at elevated pressure• Development of new compressor/expander module• Maintaining efficiency at part load may be a challenge

O/C=1.04, S/C= 2

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25

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50 60 70 80 90 100Hydrogen Recovery, %

Syst

em E

ffici

ency

, %

P= 12 atmP= 10 atmP= 8 atmP= 6 atm

80% H 2 recovery

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4 6 8 10 12 14Reformer Pressure, atm

Syst

em E

ffici

ency

, %

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Car

rier S

team

Flo

w (E

quiv

. S/C

)

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Thermal & Water ManagementThermal & Water ManagementPressurized FCS with condenser and two coolant circuitsPressurized FCS with condenser and two coolant circuits

Exhaust

Demister

Electric Motor

Hydrogen

Humidifier Heater

PEFCStack

Air

Radiator

Process Water

Humidified Air

HT Coolant

Condenser

From TIM

LT Coolant to TIM

• Large radiator (30 kg, 13.6 cm depth) and fan (700 W)• Large heat duty on air pre-heater (20 kW, 90% RH) • Difficult to maintain stack at 80oC at low loads

High Temp. Low Temp.120 kW 5.4 4.5 21.9 65 kW 12 1.6 30.0Front Area 0.6 X 0.5 m2 Pitch 1.25 mm

Power 700 W Head 380 Pa

HT Radiator 70~80°C LT Radiator 55∼70°C

Radiator Fan

Coolant Inlet Temperature

FCS Rated Power

Radiator Depth (cm) Weight (kg)

0

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10 20 30 40 50 60 70 80 90 100Vehicle Speed, mph

Hea

t Dut

y, k

W

HT RAD

LT RAD6.5% Grade600 kg Payload

120 kW FCS for Mid-size Family Sedan

Condenser

Air Humidifier / Preheater

TIM

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Thermal & Water Management Thermal & Water Management Pressurized FCS with enthalpy wheel humidifierPressurized FCS with enthalpy wheel humidifier

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0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Relative Mass Flow Rate

Cat

hode

Inle

t Rel

ativ

e H

umid

ity, %

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Cat

hode

Inle

t Air

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pera

ture

, o C

Stack Temperatutre: 80 °COxygen Utilization: 50%

47 °C

47 °C

27 °C

27 °C

-20 °C

0 °C

0 °C

Demister

Electric Motor

Hydrogen

PEFCStack

Air Exhaust

Humidified Air

Coolant

Enthalpy Wheel

• 5.6”Φ x 6” enthalpy wheel can supply air at 50-70% RH• Only HT coolant loop needed • Can maintain stack at 80oC at all loads

P = 1~2.5 atm, 40 rpm

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Direct HDirect H22 fuel cell system with highfuel cell system with high--temperature temperature polymer membranepolymer membrane

Stack issues• Faster ORR kinetics• Reduced PGM loading• Higher power density

DryBlowerHTM (120oC)HTM-ADDryCEM (2.5 atm)HTM (120oC)HTM-PD

25% RHCEM (2.5 atm)HTM (120oC)HTM-PH90% RHCEM (2.5 atm)LTM (80oC)LTM-PH

HumidificationAir ManagementMembraneSystem

BOP issues• Air management system• Heat rejection system• Water recovery system

Effect of humidity on system architecture and size• Analyzed four systems

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High temperature membrane system BOP is High temperature membrane system BOP is unattractive if membrane must be humidifiedunattractive if membrane must be humidified• Why operate dry?

- Water recovery is difficult at 120oC stack temperature.- Stack cannot be maintained at 120oC below 50% of rated power

• Incentive to develop membrane whose ionic conductivity does not depend on moisture- Elimination of air and fuel humidifiers, pre-heaters become compact- Stack can operate at 120oC at all loads

• HTM option is attractive if FCS is operated at near ambient pressure- Replace compressor/expander with blower- Stack more compact than in pressurized systems w/o an expander

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7871

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0.71.2 1.1

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LTM-PH HTM-PH HTM-PD HTM-AD

Rad

iato

r Hea

t Loa

d (k

W)

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T (k

W/K

)

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dens

er H

eat L

oad

(kW

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T (k

W/K

)1

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r Hum

idifi

er/P

rehe

ater

(kW

)

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MTD

(kW

/K)

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Fuel economy of hybrid fuel cell vehiclesFuel economy of hybrid fuel cell vehiclesGCtool-PSAT model of load-following fuel cell vehicles

Results for mid-size family sedan • 65-kW sustained at 100 mph

120-kW peak for Z-60 in 10s• FCS/ICE FE multiplier

3.0 with 55 kW ESS vs. 2.5 withstand-alone FCS

Fuel Cell System

DC/DC Converter

DC Link

Li-ion Battery

DC/AC Inverter

Traction Motor

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68

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Adju

sted

Fue

l Eco

nom

y (m

pgge

)

FHDS FUDS Combined

ICE FCS 120kW FCS 100kW FCS 80kW FCS 65kW

50% FCS Efficiency at Rated Power

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Drive cycles affect improvement in fuel economy Drive cycles affect improvement in fuel economy with hybridizationwith hybridizationChange in fuel economy

FHDS: 3%FUDS: 30% US06: 7% J1015: 34% NEDC: 19%

Braking energy/traction energyFHDS: 13%FUDS: 50%US06: 34%J1015: 53%NEDC: 35%

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62

78

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Fuel

Eco

nom

y (m

pgge

)

FHDS FUDS US06 J1015 NEDC



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86

95

27

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64

81

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79

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Rec

over

able

Bra

king

Ene

rgy

(%)

FHDS FUDS US06 J1015 NEDC

ESS 20kW ESS 40kW ESS 55kW

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Fuel cell system efficiency at rated power has only Fuel cell system efficiency at rated power has only a small effect on overall fuel economya small effect on overall fuel economy

• FCS-1: 50% efficiency (680 mV, 780 W/kg) at rated power• FCS-2: 40% efficiency (560 mV, 1150 W/kg) at rated power• Less than 2 mpgge difference in FE on combined cycles• Differences in fuel economy are even smaller with larger

fuel cell systems

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Adju

sted

Fue

l Eco

nom

y (m

pgge

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FHDS FUDS Combined



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62

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63

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20

56

65

70

71

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59

64

67

67

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Adju

sted

Fue

l Eco

nom

y (m

pgge

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FHDS FUDS Combined



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Fuel cell systems for combined heat and powerFuel cell systems for combined heat and power

Mismatch between thermal and electric demands.• Summer: High electric but low thermal demand• Winter: Low electric but high thermal demand

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0 0.2 0.4 0.6 0.8 1Fraction of Rated Power

Effic

ienc

y (%

)

Electric

Thermal

Why heat pump with FC-CHP makes sense?• Natural gas (NG) furnace, ¢2/kWh ($0.60/therm)• Heat pump (HP) with central power (CP), ¢8/kWh• Heat pump coupled with fuel cell system (FCS)

AmbientTemp HP NG CP+HP FCS+HP NG CP+HP FCS+HP

oC COP % % % $ $ $10 3.6 80 119 171 100 86 470 3.0 80 100 152 100 103 53

-10 2.5 80 81 133 100 126 60-20 2.2 80 71 123 100 145 65

Thermal Efficiency Relative Energy Cost

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Used DOE2.1Used DOE2.1--120 and GCtool for a 1200 ft120 and GCtool for a 1200 ft22 Chicago Chicago single family homesingle family home

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 500 1000 1500 2000 2500 3000 3500 4000Hour

Elec

trici

ty, k

wh

Alternative

Baseline

NOV DEC JAN FEB MAR

1200 sf Chicago Residence

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Effic

ienc

y, %

Alternative

Baseline

1200 sf Chicago R id

NOV DEC JAN FEB MAR

Baseline: FCS + NG FurnaceLow utilization: 1.6 kWe peak powerPeak FC thermal eff: 46.9%Waste heat is insufficient even to meet DHW demandSH provided by NG furnaceOverall energy efficiency ~80%

Alternative: FCS + HPHigh utilization: 5.2 kW peak powerPeak FC thermal eff: 53.3%Waste heat used for DHW plus 37% of space heating (SH)63% of SH provided by HPOverall energy efficiency ~115%30% fuel saving in winter months

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Technology transfer and collaborationsTechnology transfer and collaborationsLicensed GCtool to many domestic and international private enterprises, universities, national labs, and government affiliated organizations.

Collaborations and Interactions• Enthalpy wheel humidifier: Emprise and Honeywell• Thermal and water management: Honeywell • Hydrogen storage: TIAX• Hybrid vehicles: ANL-PSAT, Joint Battery, Fuel Cell

and SEAT Tech Team• High Temperature Membrane FC Systems:

FreedomCAR Fuel Cell Tech Team and HTMWG• Validation: ANL Fuel Cell Test Facility, Nuvera

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Future workFuture work

• Fuel Cell – Battery Hybridization study with Joint TechTeam

• Initiate joint work with UTRC on ambient-pressure fuel cell systems

• Participate in validation effort • Initiate study on cold start of fuel cell systems• Fuel cell systems for combined heat and power• Support fuel processor engineering projects at ANL• Continue to support DOE/FreedomCAR development

efforts

2004 usdoe hydrogen, fuel cells & infrastructure technologies … · 2004-06-04 · a u.s....

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