Thermoelectric Power Generation Systems and · 2009-10-28 · Thermoelectric Power Generation Systems Design, Testing, Modeling, and Optimization Madhav A. Karri Brian T. Helenbrook

Thermoelectric Power Generation Systems Design, Testing, Modeling, and Optimization

Madhav A. Karri Brian T. Helenbrook

Eric F. Thacher

Department of Mechanical and Aeronautical Engineering Wallace H. Coulter School of Engineering

Clarkson University Potsdam NY 13699

AETEG: System Design ��

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ClarksonU N I V E R S I T Y

� TEG design with Hi-Z

� GMC Sierra Truck donated by GM

� 16 Hi-Z HZ20 Modules

� Testing at Delphi-Harrison Automotive Wind Tunnels

40 50 60 70 80 90 100 110 1200

25

50

75

100

125

150

Vehicle speed (kph)

Pow

er g

ener

ated

by

AE

TE

G (

wat

ts)

B

D C

AETEG: Experimental Testing ��

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Results: TEG Power

40 50 60 70 80 90 100 110 120−5

−4

−3

−2

−1

0

1

2

3

4

Vehicle speed (kph)

Fue

l sav

ings

(%

)

D

C


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Results: Fuel Savings

40 50 60 70 80 90 100 110 120−50

0

50

100

150

200

250

300

Vehicle speed (kph)

Pow

er (

wat

ts)

Parasitc Power: Blow down work Parasitc Power: Additional coolant pumping

Parasitc Power: AETEG weight AETEG Power

D

C

B


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Results: Parasitic Losses


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Results: Exhaust Side Temperatures

0

100

200

300

400

500

600

700

800

Txc

Txi T

xo T

xm1T

xm4 T

xc T

xi T

xo T

xm1T

xm4 T

xc T

xi T

xo T

xm1T

xm4

Tem

pera

ture

( o C

)

Configuration BConfiguration C

48.28 kph

80.47 kph

112.65 kph

AETEG: System Modeling ��

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TEG model

Coolant system model

ADVISOR

thermostat condition

engine coolant temperature

mf

electrical power

1

additional coolant pumping power

power to overcome back pressure from exhaust heat exchanger &

transport TEG weight

engine rpm

Tf

me Te

parasitic losses

2

parasitic losses

1

2

�

�

�


��


TEG System Modeling

Solve for temperature distribution

Steady state energy balance equations

Newton-Raphson method

thermoelectric module

adiabatic symmetry plane

adiabatic

insulation

coolant heat exchangerTf , j

exhaust heat exchanger

wafer

Tf , j+1 , mf

Te , jTe , j-1 , me

Tc , j

Th , jsection

boundary


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Heat Exchangers

s

δ bFlow direction

L

h

s

s

L

hs

δγ

δδ

α

=

=′

=

δ

Flow direction

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Coolant System Modeling Based on coolant system in the vehicle used in experimental testing Objectives

To predict coolant flow through TEG

To predict pumping power needed to cool the TEG

To predict the change in flow rates through the other components of the coolant system

shaft

driven

pump

radiatorPCHX

by-pass

valve

kB kH

engine

kR heater

kT

Q

QHQB QR QT

Tp

pkE

TEG


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TEG Power

40 50 60 70 80 90 100 110 1200

50

100

150

200

250

300

350

400

450

500

Vehicle speed (km/h)

TE

G p

ower

(w

atts

)

HZ20M, γ = 107.6 m−1

HZQW, γ = 5158 m−1


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Fuel Savings

40 50 60 70 80 90 100 110 120−0.5

0.0

0.5

1.0

1.5

2.0

Vehicle speed (km/h)

Fue

l sav

ings

(%

)

HZ20M, γ = 107.6 m−1

HZQW, γ = 5158 m−1

�

�

�

�

�

�

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�

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System Optimization ��

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Objective function

Net Power = Total TEG Power − Parasitic Losses.

Parasitic losses:

Coolant pumping power

Blow down work

TEG weight (mobile application)

Design Variables:

Lx : length parallel to exhaust flow direction

Ly : length perpendicular to exhaust flow direction

mc : coolant mass flow rate

ρtec : thermoelectric couple density

γte : thermoelectric leg aspect ratio ( L )A

Constraints:

Th < 275C

Optimum Coolant Flow Rate ��

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10−7

10−6

10−5

10−4

10−3

10−2

0

5

10

15

20

25

30

35

40

Pow

er (

wat

ts)

10−7

10−6

10−5

10−4

10−3

10−20

10

20

30

40

50

60

70

80

TEG coolant flow (m3/s)

Cha

nge

in fl

ow r

ate

(%)

{1} Percent change total flow {2} Percent change by−pass flow {3} Percent change radiator flow {4} Percent change heater flow

TEG power

Net power

Additional coolant pumping power

{2}

{1}

{3}

{4}

Optimum Aspect Ratio ��

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100

102

104

106

108

1010

100

102

104

106

108

1010

! (1/m)

"c (

1/m

2)

Plot A: net power (Watts)

Lx = 0.05 (m), L

y = 0.05 (m), and m

c = 0.025 (kg/s)

0

2

4

6

8

10

12

14

16

10!10

10!5

100

105

1010

0

2

4

6

8

10

12

14

16

"c/! (1/m)

ne

t p

ow

er

(Wa

tts

)Plot B

100

102

104

106

108

1010

100

102

104

106

108

1010

! (1/m)

"c (

1/m

2)

Plot C: TEG power (Watts)

1e!007

1e!005

1e!003

1e!001

10!10

10!5

100

105

1010

10!7

10!5

10!3

10!1

101

"c/! (1/m)

TE

G p

ow

er

(Wa

tts

)

10!10

10!5

100

105

1010

0.3

0.31

0.32

0.33

0.34

0.35

0.36

tota

l p

ara

sit

ic l

os

se

s (

Wa

tts

)

Plot D

TEG powerparasitic losses

Preliminary Optimized Results ��

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0.2 0.4 0.6 0.8 10.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Lx (m)

L y (m)

teg power (Watts), −−− Ateg (m2)

0.1

0.2

0.2

0.3

0.4

0.5

0.6

0.7

0.8

300

350

400

450

500

550

600

650

700

0.2 0.4 0.6 0.8 10.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Lx (m)

L y (m)

net power (Watts), −−− Ateg (m2)

0.1

0.2

0.2

0.3

0.4

0.50.6

0.70.8

−600

−500

−400

−300

−200

−100

0

100

200

�

�

�

�

�

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Conclusions ��

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Designed, tested, simulated, and optimized a TEG

Heat transfer coefficients limit power density

In vehicles, weight is dominant loss, then pumping power

Optimization shows potential for improved designs

Need to increase number of variables in optimizer (heat exchangers)

Optimization code will be available

Documents

Thermoelectric Power Generation Systems and · 2009-10-28 · Thermoelectric Power Generation Systems Design, Testing, Modeling, and Optimization Madhav A. Karri Brian T. Helenbrook