2005 Deer Krommenhoek

8/11/2019 2005 Deer Krommenhoek

1/28

High Efficiency Quantum Well

Thermoelectrics for Waste Heat PowerGeneration

Milliwatts to Kilowatts of PowerJohn C. Bass

Norbert Elsner

Saeid Ghamaty

Velimir Jovanovic

Daniel Krommenhoek

Hi-Z Technology, Inc.

San Diego, CA 92126

(858) 695-6660


2/28

Measured Power FactorQuantum well is Significantly Better than Bi2Te3

Comparison of Measured Power Factor2/

0

500

1000

1500

2000

2500

3000

0 50 100 150 200 250 300

Temperature C

PowerFac

torW/cm-

K2

P a2/r B4C/B9C

N a2/r Si/SiGe

P a2/r Bi2Te3

N a2/r Bi2Te3


3/28

Quantum Well & Substrate Thermal kKapton substrate reduces thermal loss to a small fraction

Published data used togenerate chart Bulk properties

QW film is expected at1/3 bulk thermal k fromliterature

Substrate couldrepresent large thermalloss 5 micron poly Si is

~50% loss with 11micron QW film

Kapton at 25 microns is3% loss in efficiencywith 11 micron QW film

Published Bulk Quantum Well and Substrate along with

Current B i2Te3Thermal Conductivity at 200C

0.1

1

10

100

1000

SiC

B4C

PolycrystalSi

B9C

Si0.8G

e0.2

CurrentBi2

Te3

SingleCry

stal

Si

PolycrystalSi

Si0.7

5Ge

0.2

5

Kapton

QW Film & Substrate Material

ThermalConductivityW/mK

Bulk QW Materials in Blue,

Current Bi2Te3 in Green,

Bulk Substrate in Orange


4/28

Quantum Effect in B4C/B9C & Si/SiGeQuantum well ZT >3x higher than other current materials

0.0001

0.0010

0.0100

0.1000

0 100 200 300 400 500

Temperature C

FigureofM

erit1/K

P B4C/B9C

N Si/SiGe

P Bi2Te3

N Bi2Te3

P PbTe

N PbTe

P SiGe

N SiGe

Comparison of P-type B4C/B9C & N-type Si/SiGe Quantum Well

materials using measured &

, & published bulk k

versus current Bi2Te3, PbTe & SiGe materials


5/28

Quantum Well Couple EfficiencyHighest Measured Thermoelectric Efficiency

Measured QuantumWell CoupleEfficiency Versustemperature at a TC =70C

Over 100 Data PointsWere Obtained N-

leg Si/SiGe, P-legB4C/B9C

Both Films 11 mThick and Deposited

on a 5 m Thick SiSubstrate


6/28

Thermal Stability of Quantum Well CoupleN-type Si/SiGe and P-type B4C/B9C

There are nochanges inSeebeck ()and Electrical

Resistivity ()after 1400 hours(July 2005)

Power Factor(2/) shown asP/P0


7/28

QW Films Parallel or Perpendicular

to Current FlowHi-Z uses parallel approach to give higher Zs

Hi-Z approach: Substrate andfilm parallel to c urrent flow Si s ubstrate

M ultilayer film

Current I

Substrate and filmperpendicular to current flow

M ultilayer filmCurrent I

ISi s ubstrate


8/28

Two Couples with Pressure ContactsApproach successfully used in PbTe TE Generator

Surfaces must be freeof oxides

Connect quantum wellfilm to metal Thermal expansion

must be accommodated Thermal spray technique

Recent data fabricationof Si/Si0.8Ge0.2 surfaces

metallized withmolybdenum Life tested to 1400 hours


9/28

Efficiency Depends Strongly on SubstrateEfficiency improves and cost is greatly reduced with Kapton substrate

Si substrate is 80% of materials cost and large heat leak

Kapton substrate is 12% of materials cost and very small (


10/28

Comparison of Quantum Well and CurrentThermoelectric Performance

Thermoelectric

Module Material

Temperature

Difference

C

Voltage at

Maximum

Power

Maximum

Efficiency

%

Maximum

Power

W

200 1.6 5.8 14

Hi-Zs Commercial Alloys

200

250

10.0

12.4

17

20.9

60

72

Under Development

450 22.6 32.5 338

Under Development

N type Si/SiC

and P-type

B4C/B9C

Quantum Well

SiGe Substrate~5m thick (too

hot for Kapton)

N type Si/SiC &

P-type B4C/B9CQuantum Well

Kapton

substrate 25 m

thick

N & P-type bulk

Bi2Te3


11/28

Predicted Efficiency of Quantum Well

Thermoelectric ModuleEfficiency >50% Carnot at higher temperatures

N-Type Si/SiC & P-type B4C/B9C

Cold side at 50C

Based on measured

& , and l iterature(bulk thermal

conductivity)

Efficiencies compete

with gasoline & dieselengines, & fuel cells.

0

20

40

60

80

200 300 400 500 600 700 800

Hot Side Tem per atur e C

Efficiency

Carnot

Quantum

WellBi2Te3


12/28

Hi-Z Quantum Well Thermoelectric

Module and Heat Exchanger

Heat Exchanger

Coolant In

50 Watt Quantum WellThermoelectric Module

TH 300C TC 100C

N & P legs


13/28

Kapton substrate for quantum well fi lms forms module in place of

eggcrate design

Quantum well efficiency 15% versus 5% Bi2Te3Module size 6.3 x 6.3 x 1.0 cm

HeatFlow

Pressure contact

showing 2 of 49 couples


14/28

Funneled Heat Flux ModuleIncreases power & reduces amount of QW material

Method to match module resistancewith heat flux of hot and cold sideswhile increasing power putput

Thick walls funnelheat flux

Kapton substrate

funnels heat flux


15/28

Predicted Power of Quantum Well ThermoelectricModule

Radiation coupling is practical design for high temperature;

conduction or convection higher power

N-Type Si/SiC & P-type B4C/B9C

Cold side at 50C

Module is 2.5 x 2.5 in.

Thickness changed tomatch heat flux from source

Conduction

Convection

Radiation Based on measured & , and

literature (bulk thermal

conductivity)

Requires high temperatureeggcrate

0

300

600

900

1200

200 300 400 500 600 700 800

Hot Side Temper ature C

ModulePowerW

Conduction

Convection

Radiation


16/28

Hi-Z Bi2Te3 Thermoelectric PowerGenerator at 200C Temperature Difference

Bi2Te3Module Performance

Tc=50 C, Th=250 C

0

1

2

3

4

5

6

7

8

0 2 4 6 8 10 12 14 16 18

Current A

VoltageV

Efficien

cy%

0

4

8

12

16

Powe

rW

V

%

W

Present Technology


17/28

Predicted Hi-Z Quantum Well Thermoelectric Power Generator at200C Temperature Difference

QW Module N-Type Si/SiC and P-Type B4C/B9C

on Kapton Substrate at Tc=50C, Th=250C

0

5

10

15

20

25

0 2 4 6 8 10 12 14

Current A

VoltageV

Efficien

cy%

0

15

30

45

60

75

Powe

rW

V

%

W

Under Development

P di t d Hi Z Q t W ll Th l t i P G t t


18/28

Predicted Hi-Z Quantum Well Thermoelectric Power Generator at250C Temperature Difference

QW Module N-Type Si/SiC and P-Type B4C/B9C

on Kapton Substrate at Tc=50C, Th=300C

0

5

10

15

20

25

0 2 4 6 8 10 12

Current A

Volt

ageV

Efficiency%

0

15

30

45

60

75

Pow

erW

V

%

W

Under Development


19/28

1 kWe Thermoelectric Generator

Installed in Place of Muffler

A li ti f Hi Z Th l t i


20/28

Applications of Hi-Z Thermoelctrics

1 kWe TE Mounted

under PACCAR

vehicle Tested for~500,000 equivalent

miles

20 WeSelf-

Powered

Heater

Rendering of 300 We Bi2Te3 TE Generator

Under test in Sierra pick-up truck


21/28

Army Stryker Vehicle


22/28

Five kWe Quantum Well Thermoelectric

GeneratorThermoelectric Modules and Assembly with Coolant Heat Exchangers

Exhaust

Exhaust

Quantum Well Thermoelectric Modules Heat Exchangers

Under Development


23/28

Stryker Vehicle and Underarmor Quantum Well

Thermoelectric Generators

Heat Exchangers

Quantum WellThermoelectricModules

Two 5 kWe QW Generators CanBe Placed Underarmor

Exhaust

Exhaust

St k V hi l H S f U d Q t W ll


24/28

Stryker Vehicle Has Space for Underarmor Quantum Well

Thermoelectric Generators

15% Efficiency Predicted with two 5 kWe QWTE Generators Driven by Vehicle Exhaust

Under Armor Space for

APU Burner to Provide

Quiet QW TE Operation

Stryker CAT 3126 300 hp Diesel Performance Data


25/28

Stryker CAT 3126 300 hp Diesel Performance Data

Predicted QW TE Generator Power

0

2

4

6

8

10

12

1400 1600 1800 2000 2200 2400

Engine Speed rpm

E

lectricPowerkW

0

100

200

300

400

500

600

1400 1600 1800 2000 2200 2400

Engine Speed rpm

Paramete

r

Tem p CFuel r ate L/hr

Flow m 3/minEngine k WExh m ax kW


26/28

Predicted Hi-Z Quantum Well Thermoelectric Performance

Operating Conditions Th = 300 C, Tc = 100 C

Heat Flux = 10 W/cm2 Quantum well films

N-type Si/SiGe P-type B4C/B9C

Kapton substrate Reduces parasit ic thermallosses & lowers costs

Module footprint squarewith 2.35 in./side

64 modules will produce 5kWe TE Generator

Gas exhaust - 5 in. ID QW arranged in 8 in. OD, &

28 in. long generator

0

4

8

12

16

20

24

0 2 4 6 8 10 12 14 16Current A

VoltageV,E

fficiency%

0

16

32

48

64

80

96

PowerW

V

%

W

Greater than 42% Carnot Efficiency

New Quantum Well Sputtering Machine at Hi-Z


27/28

New Quantum Well Sputtering Machine at Hi Z

Operational check-out in February 2005

The new Zero Footprintbatch coater has a 34inch diameter chamber

that processes up tosix(6) 8 inch wafers ornine(9) 6 inch wafers toincrease output by

100x Currently depositingQW films on mill iwattradial heat flow sensorpower supply

2 inch diameter Radial N QW on one

side and P QW onother side of

substrate

Application of Quantum Well Thermoelectrics


28/28

Application of Quantum Well Thermoelectrics

Price per Watt competitive in several years

Quantum well raw materials cost less than currentmaterials QW $0.11/Watt

Bi2Te3 ~$1.00/Watt Process improvements reduce costs

New substrate Increased sputtering area and rate > 40 /minute New design with module surrounding substrate

DOE five year effort on Cost Effective Fabrication Routesfor the Production of Quantum Well Materials for WasteHeat Recovery from Heavy Duty Trucks UTRC prime with Hi-Z, CAT, & PNNL

Documents

2005 Deer Krommenhoek