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Introduction to Thermoelectric Effects And Their Applications in Energy and Environment Shang-Fen Ren Department of Physics, Illinois State University Normal, IL 61790-4560 [email protected]. Research Supported by National Science Foundation, Research Corporation, - PowerPoint PPT Presentation
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Introduction to Thermoelectric Effects
And Their Applications in Energy and Environment
Shang-Fen Ren Department of Physics, Illinois State University
Normal, IL 61790-4560
Research Supported by National Science Foundation,
Research Corporation, and Caterpillar, Inc
Main Research Collaborators
Wei Cheng (Beijing Normal University)Gang Chen (MIT)
Walter Harrison (Stanford)Peter Yu and Sam Mao (UC-Berkeley)
Andrew McGilvray, Bo Shi, and Mahmoud Taher (Caterpillar)
Research Students (1994-present)
David Rosenberg, Latanya Molone, Garnet Erdakos, Heather Dowd, Jason
Stanford, Maria A. Alejandra, Chad Johnson, Kim Goodwin, Joel Heidman,
Paul Peng, Josh Matsko, Brian Mavity, Rory Davis, Nathan Tovo, Victor Nkonga, Shelley Dexter, Scott Gay, Tim Hughes, Gabriel
Altay, Louis Little, Victor Nkonka, Benjamin Thompson, Jonathan Andreason, Zoe
Paukstys, Colin Connolly, Marcus Woo, Courtney Pinard, Danthu H.Vu, Valerie Hackstadt, Derek Wissmiller, Scott Whitney, Chris S.
Kopec, Erika Roesler, Elizabeth Williams,Trina Karim, Mike Morrissey,
Nick Jurasek, Nathan Bogue, Mid-hat Abdulrhman, Maggie Hansen, Jade Exley
Outline
Thermoelectric Effect
What is Thermoelectric Effect (TE)Potential Applications of TE
TE and Nanotechnology
TE Applications in Energy and Environment
Research Collaboration on TE with Caterpillar
Thermoelectric Effects
Discovered in 1821 by Thomas Johann Seebeck: observed a compass needle to move when placed in the vicinity of a closed loop of two dissimilar metal conductors joined together at the ends to make a circuit, when the junctions were maintained at different temperatures.
Introduction to Thermoelectrics
Heat in
Current out+-
TThh
TTcc
NN PP
Thermoelectric Couple Thermoelectric
elements (legs)
Two legs of a thermocouple. The magnitude of the thermoelectric voltage is proportional to the difference of two temperatures.
Most materials with good thermoelectricity efficient are semiconductors. Two legs are made by N-type and P-type of semiconductors respectively.
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Thermoelectrics Nomenclature
+
-
Thermoelectric Device
(Module)
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Thermoelectrics Nomenclature
Thermoelectric System/Application
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Commercial Bulk TE Modules
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Thermoelectrics Power Generation (Seebeck Effect)
+
-
+
-Electric Power out
Po
Thermal Power in
QhTThh
TTcc
h
o
h
cav
av
h
ch
Q
P
T
TZT
ZT
T
TT
1
11max
Carnot Efficiency
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Thermoelectrics Cooling (Peltier Effect)
in
c
av
c
hav
ch
c
P
Q
ZT
T
TZT
TT
TCOP
11
1
max
+
-
+
-Electric Power in
Pin
Thermal Power Out
Qc
TThh
TTcc
Peltier Effects was discovered 13 years later.
Applications of Thermoelectrics (I)
TE Power Generation (Seebeck)
Power generation for special applications
SpaceMilitary
Waste heat to energy (green energy)
Applications of Thermoelectrics (II)
TE Cooling (Peltier)High accuracy thermometer Environmentally-friendly refrigeratorNew air-conditioningCooling for electronics
Simple system, small volume, high accuracy, high sensitivity, highly reliable, long lifetime, environmentally friendly
Thermoelectric Efficient
ZT=
T 2
Figure of Merit Figure of Merit ZTZT
α is the Seebeck coefficient of the material (V/K)is the Seebeck coefficient of the material (V/K) is the electrical resistivity of the material (Ωm)is the electrical resistivity of the material (Ωm) is the thermal conductivity of the material (W/mK)is the thermal conductivity of the material (W/mK)
The heart of the research is to look for materials that conduct electricity well but conduct heat poorly (phonon glass and electron crystal (PGEC)).
Most materials have a ZT much less than 1. Thermoelectric systems in automobiles requires a ZT of about 2. To substitute conventional refrigerators requires a ZT of about 4
Performance of Thermoelectric Generator as Function of ZT
For above temperatures, the Carnot efficiency is about 61 percent, making the TE generator to be about 24 to 30 percent efficient with TE materials with ZT between 2 and 3.
Coefficient of Performance for Thermoelectric Cooling
as Function of ZT
Figure of Merit – Bulk
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Bulk Module Markets
Night visionNight vision
Radioisotope thermoelectric Radioisotope thermoelectric generatorgenerator
Electronics CoolingElectronics Cooling AutomobileAutomobilePortable FridgePortable Fridge DehumidifierDehumidifier
Offshore power generationOffshore power generationChillerChiller
In high end cars (GM, Ford, Toyota, Nissan, Lexus, etc) .
Huge market!!! Over 4 million units sold so far.
Climate Control Seat (CCS) System Vehicle Application
Solid state refrigerators may replace traditional compressor refrigerators in the future
Progress in Thermoelectric Efficiency ZT
0
0.5
1
1.5
2
2.5
3
3.5
4
1940 1960 1980 2000 2020
YEAR
FIG
UR
E O
F M
ER
IT (
ZT
) max
Bi2Te3 alloyPbTe alloy
Si0.8Ge0.2 alloy
Skutterudites(Fleurial)
PbSeTe/PbTeQuantum-dotSuperlattices(Lincoln Lab)
Bi2Te3/Sb2Te3
Superlattices(RTI)
Dresselhaus
(MichiganState)
Figu
re o
f Mer
it (
ZT)
max
Year
0
0.5
1
1.5
2
2.5
3
3.5
4
1940 1960 1980 2000 2020
YEAR
FIG
UR
E O
F M
ER
IT (
ZT
) max
Bi2Te3 alloyPbTe alloy
Si0.8Ge0.2 alloy
Skutterudites(Fleurial)
PbSeTe/PbTeQuantum-dotSuperlattices(Lincoln Lab)
Bi2Te3/Sb2Te3
Superlattices(RTI)
Dresselhaus
(MichiganState)
Figu
re o
f Mer
it (
ZT)
max
Year
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Thermoelectrics Materials: Bulk and Nano-Scale
Less than 5% conversion efficiency
BulkBulk
• More than 40 years
• Niche applications
• Well established product
Nano-ScaleNano-ScalePredicted with 30%
conversion efficiency
• Less than 10 years
• Potential for a wide variety of applications
• Still being incubated at small companies, universities and national labs
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
A World from Macro to Nanoscale
1 nm = 10-9
m
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Introduction: Nanoscience and Nanotechnology
What is a Nanostructure?The word “nano” means 10-9 . So a nanometer is one billionth of a meter. In general, nanostructures are objects in the size range from tens to hundreds of nanometers. Nanoscience concerns the study of objects in this size range, and nanotechnology is to fabricate and work on objects in this size range.
These materials also have tunable properties that makes them valuable for many different real world applications.
Why nano?The nanoworld provides scientists with a rich set of materials that can be useful of probing the fundamental nature of matter.
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Examples of Nanostructures
Carbon Nanotubes (Ren, et al., Stanford Science, 1998)
Chemical Etching of Porous Silicon
by Thomas Research Group
C60 discovered by Kroto in 1985
Self-assembled Ge pyramid 10nm
(www.nano.gov)
48 Fe atoms on Cu (111) surface, Quantum Corral, by
D. Eigler,IBM
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Properties of Nanostructures: Electron Density of States as a Function of Dimensionality
Quantum wires(QWR)
1-D
Quantum well (QW) 2-D
Quantum Dots (QD) 0-D
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Properties of Nanoscale Materials: CdSe Quantum Dots
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Properties of Nanoscale Materials: Size and Band Gap
Electrons: Blue shift of the electronic band gap
Uncertainty
Principle
US Energy Flow Trend (2002)
Massive Quantity of “Waste” Energy
97% Oil Dependent
Imported Oil
Massive Quantity of “Waste” Energy
97% Oil Dependent
Imported Oil
Unit: quads, (1quads =1 quadrillion BTU, 1
BTU=1055J)
Opportunities for Recovery of Waste Heat in Transportation
Co
mb
us
tio
n
30% Engine
100
%
40% Exhaust
Gas
30%Coolant
5% Friction & Radiated
25Mobility &
Accessories
Gas
olin
e
Gas
olin
e
Co
mb
us
tio
n
30% Engine
100
%
40% Exhaust
Gas
30%Coolant
5% Friction & Radiated
25Mobility &
Accessories
Gas
olin
e
Gas
olin
e
Gas
olin
eG
asol
ine
Gas
olin
eG
asol
ine
Distribution of Fuel Energy in Passenger Vehicles
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Goal for TE in Transportation, a Research Roadmap
By 2012, achieve at least 25% efficiency in advanced thermoelectric devices for waste heat recovery to potentially increase passenger and commercial vehicle fuel economy by 10%.
DOE Initiative for a Science-Based Approach to Development of Thermoelectric Materials for Transportation Applications, ORNL, Nov. 2007
Technical Barriers
Unusual combination of properties
Matching n- and p- type materials
Performance often dependent on doping
Difficult metrology and lack of standards
Scale up of synthesis and processing of thin-film materials from lab
scale
Cost effective thermoelectric materials and devices
System issues critical to operation of thermoelectric devices
Science-based Approach for TE material Discovery
Synthesis &Processing
Evaluation
Computation(Modeling & Simulation)
Characterization
New Materials
Synthesis &Processing
Evaluation
Computation(Modeling & Simulation)
Characterization
New Materials
Materials Technology Flow for Solid State Waste Heat Energy Recovery
We have developed a physics-based model that simulates the structure of multilayered nanostructures.
Our modeling tool is used to predict the TE property of various multilayered structures with different structural configurations and doping concentrations.
Our calculations have helped with the understating of the TE property of nanostructure affected by various conditions, and the results are used to guide the experimental research in developing nanostructured thin-film based materials for high-efficiency TE applications.
Collaboration with Caterpillar
Potential Location for TE Generator
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
Caterpillar’s 550 HP Heavy Truck Equipped with TEG
TE Generator for Light Vehicles
Introduction to TE and Their Applications in Energy and Environment By Shang-Fen Ren
TE Materials for Applications in Energy and Environment