Space probe to the Jupiter From JPL, NASA

Radioisotope Thermoelectric Generator (PbTe)

Introduction of Thermoelectric Materials and Moduels

1st Semester of 2012 2012.03.15, Thursday Department of Energy Science Sungkyunkwan University

Objective

The topic of energy conversion thermoelectric (TE) systems and Fundamental transport properties, Material syntheses, Efficiency evaluations, Module fabrications for practical applications etc. The physics of semiconducting thermoelectric phenomena, Seebeck and Peltier effects, Thermal conduction, the course will introduce The materials From the state-of-the-art bulk Bi-Te materials To newly developed nanostructured materials (low-dimensional systems) Hybrid system utilizing thermoelectric conversion

1 Thermoelectric Phenomena and Conversion Efficiency

2 Thermoelectric Transport Theory I : Electrical Properties

3 Thermoelectric Transport Theory II : Thermal Properties

4 Thermoelectric System : Current and Future of Modules

5 Materials Preparation : Bulk and Film

6 Measurement of Thermoelectric Properties

7 Applications : Power Generation and Heat Cooling

8 Mid-term Exam

9 Thermoelectric Materials : State-of-the-art

10 Thermoelectric Materials : Intermetallics

11 Thermoelectric Materials : Oxides

12 Thermoelectric Materials : Phonon Glass and Electron Crystal (PGEC) Materials

13 Theory and Modeling in Nanostructured Thermoelectrics

14 High efficiency in Low Dimensional Materials

15 Hybrid Energy Conversion Systems of Thermoelectrics

16 Final Exam

Plan

Textbooks

2. Thermoelectrics Handbook – Micro to Nano Edited by D. M. Rowe, 2006, Taylor & Francis.

1. CRC Handbook of Thermoelectrics Edited by D. M. Rowe, 1995, CRC Press Inc.

3. Heavily Doped Semiconductors Victor I. Fistul’, 1969, Plenum Press.

4. Thermal Physics Charles Kittel, 1969, John Wiley & Sons, Inc.

Seebeck Effect (1821) Temperature Difference Electrical Current Power Generation High Temperature Region

Peltier Effect (1834) Electrical Current Temperature Difference Heat Cooling Low Temperature Region

Thermoelectric Effect : Electrical Energy <---> Thermal Energy

Thomas Johann Seebeck (1770 – 1831)

Jean Charles Athanase Peltier (1785 – 1845)

Thermoelectric Effect : Seebeck Effect

Thermoelectric Materials

ZT=0.5

1950

1980

1990

2000

2010

ZT=2

Bi-Te, Bi-Se, Sb-Te

Pb-Te, Ge-Si, 3d Silicide

PGEC, Intermetallics, Oxide

Thin Film (Superlattice), Nanowire

Complex Structure Nanostructure Imbedded Bulk

ZT=1

ZT=0.8

Advantage

Compactness and Quietness

(No moving parts)

Available for localized heating and cooling

Environmentally friendly

Accurate Temperature control ( 0.01K )

= (T / Thot )[(1+ZTave )1/21] /

[(1+ZTave )1/2 + ( Tcold / Thot )]

Tave = (Tcold + Thot ) / 2

T = Thot Tcold

Energy Conversion Efficiency

Thermoelectric Module

Thermoelectric Materials : Efficiency

ellat

: Power Factor /2

lat : Lattice Thermal Conductivity

el : Electronic Thermal Conductivity

TZT

2

: Seebeck Coefficient (Thermoelectric Power)

: Electrical Resistivity

: Thermal Conductivity

Dimensionless Figure of Merit, ZT Trade-off

Thermoelectric Materials : Efficiency

• Black Box Cooling • Cold Chambers • Cold Plates • Compact Heat Exchangers • Constant Temperature Baths • Electronics Package Cooling • Heat Density Measurement • Integrated Circuit Cooling • Infrared Detectors • Infrared Seeking Missiles • Laser Diode Coolers • Microprocessor Cooling

• Microtome Stage Coolers • Power Generators (small) • Precision Device Cooling (Lasers and Microprocessors) • Refrigerators (Aircraft, Automobile, Boat, Hotel, Insulin, Portable/Picnic, Pharmaceutical, RV) • Semiconductor Wafer Probes • Thermal Viewers and Weapons Sights • Thermal Cycling Devices (DNA and Blood Analyzers) • Wafer Thermal Characterization • Water and Beverage Coolers • Wet Process Temperature Controller • Wine Cabinets

Blue : Cooling Red : Power Generation

Applications of Thermoelectrics

Niche Markets

Snyder, Toberer, Nat. Mater. 2008

Thermoelectric Research : Current Status

Target : High Conversion Efficiency of Thermoelectric Devices

Module : Accumulation of Elements, Contact Resistance (Welding), Shape Diversity for Micro-Scale (Thin Film)

System : Circumstance Suitability (Generation), Diversity of Mass Conversion System, Hybridization with other renewable energy system

Materials : High Efficiency (High ZT), New Materials and Various Categories (Limitation to Heavy Metal Compounds), Properties for Hybridization (Magnetic Semiconductor for Magnetocaloric) (Low Workfunction for Thermionic)

Thin Film

Cascade Conventional

Solar absorber + TE Custom Cooling Device D. Kraemer et al., Nat. Mater. 20011