Thermionic Energy Conversion

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Thermionic Energy Conversion

• Dr Peter Tanner

Sustainable Energy Solutions 11 November 2003
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Emitter
Collector
Heat Out
Heat In
Electron Current
Load
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Problems to be overcome

• Find material with high enough emission
• Space charge

Sustainable Energy Solutions 11 November 2003
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Richard-Dushman Equation
J AT2e
Sustainable Energy Solutions 11 November 2003
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Types of TEC

• Closed space diode
• Caeisum diode
• TECs with auxiliary discharge

Sustainable Energy Solutions 11 November 2003
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EMITTER MATERIALS
1000
1000
LAD-Scandate

100
100
Scandate
Current density (A/cm²)
Optim. Alloy

10
M

Alloy Disp.
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Dispenser

SO
L S
1
1
Ba-Oxide
Th-W
Surface Analysis
Capabilities
0,1
W
0,1
1900 1920 1940
1960 1980 2000
Year
7
KARAT
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Two encouraging aspects

• Programs for computer simulation of plasmas now
  available
• Significant improvements in emitter materials
  over recent years

Sustainable Energy Solutions 11 November 2003
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TOPAZ-II TFE Cross Section
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MTC NEW HORIZON
Choose collector and emitter substrates
Install collector and emitter surfaces
(3)
(2)
(4) Etch collector surface
Bond collector to emitter substrate
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• Some applications
• Electric vehicles
• Topping cycle
• Cogeneration
• Solar cell
• Domestic heating and electricity supply
• In-pile system

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• SUMMARY
• Developments making TECs more feasible
• Advances in electronic emitter materials
• New methods of plasma analysis by computer
  simulation
• Application of microminiaturisation techniques