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Thermoelectric Device Enhancement
- f Heatsink Performance
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Thermoelectric Device Enhancement of Heatsink Performance 1 - - PowerPoint PPT Presentation
Thermoelectric Device Enhancement of Heatsink Performance 1 - - PowerPoint PPT Presentation
Thermoelectric Device Enhancement of Heatsink Performance 1 Introduction Thermoelectric devices as heat sink enhancement Thermoelectrics are often treated as commodity components little thought devoted to proper sizing
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Heat Absorbed Heat Rejected
Positive (+) Negative (-) Electrical Conductor (Copper) p-Type Semiconductor n-Type Semiconductor Electrical Insulator (Ceramic)
Thermoelectricity
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Typical thermoelectric system
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Problem – designing a thermoelectric into an application
( )
− − − =
C H C C
T T G I IT N Q κ ρ α
2
2
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Problem – designing a thermoelectric into an application
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Since TH and TC are unknown, QC and QH are also unknown From the QC equation, N and G are not yet known
( )
− − − =
C H C C
T T G I IT N Q κ ρ α
2
2
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- Existing methods
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Development of Method Assumptions
- QC, TC, θ, and I are predetermined
- Cold side thermal resistance is to
be ignored
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( )(
)
ave C H ave OPT OPT
ZT T T T I G + + − = 1 1 κ α
( )
ave ave C H OPT
T T T T G I α ρκ α κ + + − =
2
1 1 θ
H amb H
Q T T + =
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∆ − − = ) 2 2
2 OPT OPT OPT C OPT C OPT
TG G I T I Q N κ ρ α T N IR V ∆ + = α 2 Then solve for a new TH and start another iteration, solving for GOPT and NOPT. P Q Q
C H
+ =
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Q: Will a thermoelectric be an enhancement in my application? The iteration method provides the best possible TED – if this does not work, then a thermoelectric solution is not feasible with for this application.
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Results
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Thermal Resistance vs. TC
20 30 40 50 60 70 80 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Heat sink thermal resistance (°C/W) T C (°C)
Tc, heat sink without TED Tc, 3.5A Tc, 4A Tc, 8A
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