Outline of new materials research and applications for thermoelectrics at CSIRO

1. Thermoelectrics Capabilities
CSIRO Materials Science and Engineering (CMSE)
Dr. Nick Savvides, Dr. Karl Müller, Dr. Haiyan Chen,
Jack Ling, Dr. Dong Chen, Sarah Miller, and Dr.
Howard Lovatt

2. Motivation
α 2σ
• Figure of merit for thermoelectrics ZT = T
κ
• Current best materials have ZT ~1
• Typical system efficiency 5 - 12%
• ZT ~ 2 would give up to 25% efficiency
• (For reference, current combustion engine efficiency ~25%!)
1.0
ZT: figure of merit
Bi2Te3
0.8 PbTe
0.6
BiSb Si1 xGex
0.4
0.2
0.0 Room temperature
0 200 400 600 800 1000 1200
Temperature (K)
CSIRO. Thermoelectric Capabilities

3. Materials Research
• Aims of present work
• Prepare fine Mg2Si, Mg2Ge, Mg2Sn and their solid solutions
• Characterize the microstructure, TE prop: α, σ, κ
• Optimize ZT by nanostructuring …..
• Processing
• Ingots & single-crystals
• direct-melting, Bridgman method, zone-melting…
• Dense compacts:
• Reduction to nano-powders, mechanical alloying, hot pressing…
• Characterization
• Microstructure & composition: XRD, SEM, TEM, EDX…
• TE properties: Seebeck, resistivity, thermal conductivity ….
• Device assembly & testing…..
CSIRO. Thermoelectric Capabilities

4. Seebeck Coefficient
Compound Literature CSIRO
Mg2Si 200 – 500 µV/K 330 – 350 µV/K
Mg2Ge 200 – 700 220 – 360
Mg2Sn 20 – 115 135 – 188
αy Isotropy
Mg2Sn
αx
CSIRO. Thermoelectric Capabilities

5. Electrical Conductivity
Dramatic increase in electrical conductivity with control of eutectic composition
CSIRO. Thermoelectric Capabilities

6. Theoretical Materials
Motivation
• No theoretical limit to performance
• Recent reports of experimental
materials with high ZT
CSIRO. Thermoelectric Capabilities

7. Theoretical Materials
Result
• CSIRO has a provisional patent on a novel material
- offers high ZT ~10
Nanoparticle
Electron Reservoir
~100 nm
Molecular
Quantum Dot
0D ~1 nm
CSIRO. Thermoelectric Capabilities

8. Genset Waste Heat Recovery
• 30 kW natural gas Genset
• Waste heat from exhaust 18kW
• Target electricity 500W
• FY 07/08: Demonstration unit
Electric Output Expander
+17kW
Condenser
Water Heater
Boiler
Thermoelectric 95°C
-34kW +34kW -30kW
90°C
520°C 150°C 85°C
+17kW
Pump
5.4 L/min
CSIRO. Thermoelectric Capabilities

9. TEG System in Construction
CSIRO. Thermoelectric Capabilities

10. Solar Thermoelectric Design and Analysis
• Motivation: To design and evaluate solar thermoelectric
systems suitable for urban, rural and remote locations
• Facilities and Capabilities:
• The National Solar Energy Centre in Newcastle has tracking solar
collector systems including parabolic troughs and heliostat array. A
solar dish is located at Lucas Heights
• The National Solar Energy Centre continuously records accurate
local weather data for system analysis
• Design and analysis of solar thermal systems using the latest tools
and techniques developed by, and in collaboration with, the
international solar thermal community
• Multidisciplinary team of physicists, electrical, electronic,
mechanical and chemical engineers with expertise in optics, fluid
dynamics and thermodynamics
CSIRO. Thermoelectric Capabilities

11. Concentrating Solar Facilities
CSIRO. Thermoelectric Capabilities

12. DET Thermoelectric Activities
• Engaging with major engineering company on feasibility of
harnessing energy from the environment, including a low
temperature, non-concentrating, solar powered thermoelectric
device ($70k)
• Performing an techno-economic appraisal of a solar
thermoelectric trough concept
• Evaluating technologies for harnessing energy from the
environment to power sensors. Literature review in progress
CSIRO. Thermoelectric Capabilities

13. Power Conditioning and Control
Power generation
• Convert/invert voltage
• Need to find maximum power point and convert/invert voltages
CSIRO. Thermoelectric Capabilities

14. Applications
• Medical hyperthermia/hypothermia
• Energy conservation
• Waste heat energy recovery
• Sensing
• Refrigeration
• Solar thermal power generation
CSIRO. Thermoelectric Capabilities

15. CSIRO Material Science and Engineering (CMSE)
Dr. Howard C Lovatt
Stream Leader - Energy Conversion Devices
Phone: +61 2 9413 7412
Email: howard.lovatt@csiro.au
Web: www.csiro.au
Thank You
Contact Us
Phone: 1300 363 400 or +61 3 9545 2176
Email: Enquiries@csiro.au Web: www.csiro.au