Solid-State Energy Conversion Overvie · 2014-03-18 · Vehicle Technologies Program eere.energy.gov 1 Solid-State Energy Conversion Overview John W. Fairbanks. Department of Energy

Vehicle Technologies Program eere.energy.gov

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Solid-StateEnergy Conversion Overview

John W. FairbanksDepartment of EnergyVehicle Technologies

Annual Merit ReviewJune 11, 2010


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Overview

• Potential of Thermoelectric Applications in Vehicles

• Thermoelectric Materials

• Vehicular Thermoelectric Generators

• Vehicular Thermoelectric Air Conditioner/Heater

• Summary


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Vehicular ThermoelectricGenerators (TEG’s)

•Generate Electricity Without Introducing any Additional Carbon into the Atmosphere


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Vehicular Thermoelectric Air Conditioner/Heater (TE HVAC)

• Maintain Vehicle Occupant Comfort With Major Reduction of Fuel Use

• Eliminate Vehicular Use of R134a Refrigerant Gas which has 1300 times Greenhouse Gas Effect as CO2, the Primary Greenhouse Gas of Concern


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Front View Rear View

First Application of Thermoelectric Generator in Vehicle


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Modular HVACVariable speed compressor more efficient and serviceable3X more reliable compressor no belts,

no valves, no hoses leak-proof refrigerant lines instant electric heat

StarterGenerator

MotorBeltless engine

product differentiation improve systems design flexibility more efficient & reliable accessories

Shore Powerand InverterSupplies DC Bus Voltage from 120/240 Vac 50/60 Hz Input Supplies 120 Vac outlets from battery or generator power

Down ConverterSupplies 12 V Battery from DC Bus

AuxiliaryPower Unit

Supplies DC Bus Voltage when engine is not

running - fulfills hotel loads without idling main engine

overnight

Compressed Air ModuleSupplies compressed air for brakes and ride control

Electric WaterPump

Electric Oil PumpVariable speed

Higher efficiency

Truck ElectrificationElectrify accessories

decouple them from engineMatch power demand to real time need

Enable use of alternative power sources

Beltless or More Electric Engine

Higher reliability variable speedfaster warm-up less white smoke

lower cold weather emissions


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Current TE Materials

P-type TE material N-type TE material

Ref: http://www.its.caltech.edu/~jsnyder/thermoelectrics/


81017 1018 1019 1020 1021

α σ

Carrier Concentration

Tota

l ΚZT

insu

lato

r

met

al

semiconductor

Unusual Combinationof Properties

TE Materials Performance:Figure of Merit (ZT)

σ 2

ZT =α

(κe + κL)• T

Seebeck coefficientor thermopower

(∆V/∆T)

Electrical conductivity

Total thermal conductivity

σ α2α

σ

κ

ZTmax

κL

κe

σα2 = Power Factor

σ= 1/ ρ = electrical conductivity

ρ = electrical resistivity


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Nanoscale Effects for Thermoelectrics(courtesy Millie Dresselhaus, MIT)

PhononsΛ=10-100 nm

λ=1 nm

ElectronsΛ=10-100 nmλ=10-50 nm

Electron Phonon

Interfaces that Scatter Phonons but not Electrons

Mean Free Path Wavelength


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Atomic Structure of Skutterudites

Cobalt atoms form a fcc cubic latticeAntimony atoms are arranged as a square planar ringsThere are 8 spaces for the Sb4 units6 are filled and 2 are empty

CoSb3 [Co8(Sb4)6]

RxCoSb3

Atoms can be inserted into empty sites. Atoms can “rattle” in these sites – scatter phonons and lower the lattice thermal conductivity.


111. X. Shi, et al. Appl. Phys. Lett. 92, 182101 (2008)2. X. Shi, et al., submitted (2009)

T (K)200 400 600 800 1000 1200 1400

ZT

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Bi2Te3

PbTe SiGe

Ba0.24Co4Sb12

Ba0.08Yb0.09Co4Sb12

Triple-filled

Yb0.12Co4Sb12

ZTave = 1.2

• Ba0.08La0.05Yb0.04Co4Sb12.05ο Ba0.10La0.05Yb0.07Co4Sb12.16

Highest ZT Achieved withTriple-filled Skutterudites


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Key Element 1: Materials. Key Element 2: Thermal management. Key Element 3: Durability. Key Element 4: InterfacesKey Element 5: Heat sink design. Key Element 6: Metrology.

DOE/NSF Partnership inThermoelectrics

University/industry collaboration, $9M/yr over 3 yearsLOIs were due May 21, 2010Proposals due June 22, 2010


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Com

bust

ion 30%

Engine

Vehicle Operation10

0%

40% Exhaust

Gas

30%Coolant

5% Friction & Radiated

25Mobility &

AccessoriesGas

olin

e

Gas

olin

ega

solin

e

Typical Waste Heat from Gasoline Engine Mid Size Sedan


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ZT

0.1

0.2

1

700

500

300

Temperature [

C]

exhaust gas temperature

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0.10

1.00

10.00

100.00

500 1000 1500 2000 2500 3000 3500 4000 4500

-750

-550

-350

-150

50

250

450

650

0.5

400

600

ZT (1000W)

ZT (500W)

Distance behind three way catalyst [mm]500 1000 1500 2000 2500 3000 3500 4000 45000

0

BMW 530iA at 130 km/h, Exhaust gas back pressure limited to 30mbar at 130km/h

Max hot side temperature of a module

SI Engine Exhaust Temperature Profile with Potential TEG Locations

Slide courtesy of BMW


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TEG‘s are Ideally Compatible with Regenerative Braking

BSST TEG (prognosis)

BMW TEG 2007

Slide courtesy of BSST


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-

BMW X-6

Courtesy of GM

Demonstration TEGs In Ford Fusion,BMW X6 and Chevy Suburban

tatimbario

Sticky Note

OK to use ford pic?

tatimbario

Sticky Note

ok to use BMW pic?


17116i 530dA 750iA

190 W2%

330 W3,5%

390 W4%

750 W6%

1000 W8%

Average demand for electric power

Fraction of electricity on total FC.

NEDC customer NEDC customer NEDC customer

Thermoelectric Power Generation –The Next Step for CO2 Reductions

400W4%

Source: BMW Group

tatimbario

Sticky Note

ok to use pics?


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BMW integrating a TEG with the EGR cooler of a Diesel engine.

The infrastructure for a TEG (water cooling, by-pass, exhaust-flap) is available in today‘s EGR coolers

BMW Exhaust Gas Recirculation(EGR)-TEG

Source: BMW Group


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BMW Diesel Engine EGR TEG.

Source: BMW Group


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BMW EGR-TEG.

Source: BMW Group


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BMW EGR-TEG.

Source: BMW Group


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• Develop test protocols and metrics for real-world automotive TE HVAC system usage

• Use CAE, thermal comfort models, and subject testing to optimize heating/cooling node locations

• Develop high-efficiency advanced thermoelectric materials and assemblies

• Design, integrate, and validate performance of a production prototype TE HVAC in a demonstration vehicle

TE HVAC Approach


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Zonal Thermoelectric Air Conditioner/Heater (HVAC) Concept

Zonal TE devices located in the dashboard, headliner,A&B pillars and seats / seatbacks


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Thermoelectric HVAC Advantages for PHEV, HEV, EV or FC Vehicles

• Occupant Heating During Battery Propulsion(No Engine Heat)

– Resistance Heating InefficientOccupant Cooling– Electric Compressor Refrigerant Gases

> Need R134-a ReplacementThermoelectric HVAC Zonal Concept

> Cooling COP 1.5 Augment or Replace Compressed Gas Unit

> Heating COP 2.5Replace Resistive Heaters

Typical COP 1.0


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Battery Temperature Impacts PHEV, HEV and EV Performance and Service Life

Temperature affects battery operation• > Round trip efficiency and charge acceptance• > Power and energy• > Safety and reliability• > Life and life cycle cost

Battery temperature impacts vehicle performance, reliability, safety, and life cycle cost


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• Thermoelectric Generator providing nominal 5-6% fuel economy gain augmenting smaller alternator

• “Beltless” or more electric engines• Thermoelectric HVAC augmenting smaller A/C

• Thermoelectric Generators installed in diesel or gasoline engine exhaust– 55% efficient heavy duty truck engine– 50% efficient light truck, auto

• Thermoelectric Generators and HVAC w/o alternators or A/C

• Aluminum/Magnesium frame & body replacing steel(Process waste heat recovery) mass market cars

• 35% efficient Thermoelectrics w 500 0C ∆T– Replace Internal Combustion Engine (ICE)– Dedicated combustor burns any fuel

{

Near Term(3-5 yrs)

Mid Term(6-15 yrs)

{

Long Term(16-25 yrs) {

Vehicular Thermoelectric Application Possibilities

Documents

Solid-State Energy Conversion Overvie · 2014-03-18 · Vehicle Technologies Program eere.energy.gov 1 Solid-State Energy Conversion Overview John W. Fairbanks. Department of Energy