Thermoelectricity

THERMOELECTRIC POWER

GENERATION

BY:

P.KIRANMAYI

DEPARTMENT OF EEE

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CONTENTS

Introduction

Why Thermoelectricity ???

Principle

Working and Construction

Material of choice for TEG

Simulations

Advantages and Disadvantages

Applications

Conclusion

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INTRODUCTION:

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THERMOELECTRIC POWER GENERATION

USING WASTE - HEAT ENERGY AS AN

ALTERNATIVE GREEN TECHNOLOGY

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Why thermoelectricity ???

Increasing energy demand!!!

Increasing pollution!!!

Increasing IC heat!!!

Green energy production by

thermoelectricity.

Automobile waste heat thermoelectric

power generation.

On chip thermoelectric cooling.

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Why thermoelectricity ???

IEA,

WEO,

2008

Nasty Problems

Green energy

Production by

thermoelectricity

Automobile waste

heat thermoelectric

power generation

Choudhary et. al,

Nature nano. (2009)

On chip

thermoelectric

cooling (BiTe )

Green Solutions from thermoelectricity !!!

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PRINCIPLE

SEEBECK EFFECT, PELTIER EFFECT.

WORKING MECHANISM OF

A THERMOCOUPLE.

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SEEBECK EFFECT

S= dV / dT;

S is the Seebeck Coefficient with units of Volts per Kelvin

S is positive when the direction of electric current is same as the direction of thermal current

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PELTIER EFFECT:

П <0 ; Negative Peltier coefficient

High energy electrons move from right to left.

Thermal current and electric current flow in opposite directions.

(electronic)

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PELTIER COOLING

П >0 ; Positive Peltier coefficient

High energy holes move from left to right.

Thermal current and electric current flow in same direction.

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WORKING

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Fig: schematic diagram of TEG.

Thermoelectric Materials

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( )e g

TZT

- Seebeck Coefficient

- Electrical Resistivity

- Thermal Conductivity

e – Electronic

g – Lattice

Figure of Merit:

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Material of choice for

thermoelectricityTE Parameters

Materials

Metals

Insulators

Semiconductors

Semiconductors most suitable TE material.

Allow separate control of G (electrons) and κ (phonons).

Electrical

Conductivity

(G)

Seebeck

Coefficient

(S)

Thermal

Conductivity

(κ)

High~102 W/m-K

High

Moderate10-3S/m

High~120 μV/K

Very High~107 S/m

Low ~ 10μV/K

Low~10-2-10-4 W/m-K

Low~10 W/m-K

Extremely

low (~10-10S/m)

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SIMULATIONS

A TEG MODULE MODEL WITH INITIALLY 8

TEG MODULES WAS RUN

THEORETICAL POWER OBTAINED –

56.347W

POWER OBTAINED IN SIMULATION –

51.42W

TO INCREASE OUTPUT NUMBER OF TE

MODULES INCREASED TO 18

NEW OUTPUT – 122.67W 13

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ADVANTAGES AND

DISADVANTAGESADVANTAGES:

Environmentally friendly

Recycles wasted heat energy

Scalability, meaning that the device can be applied to any size

heat source from a water heater to a manufacturers equipment

Reliable source of energy

Lowers production cost

DISADVANTAGES:

TE material is expensive

Structural failure of TE element at high temperatures

Electrical resistivity increases 14

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APPLICATIONS

Water Cooler

Cooled

Car Seat

Electronic Cooling

Laser Cooling

TE

Si bench

1 kW Generator for Diesel Truck

Demonstrated capability to produce

1 kW of

electric power from Diesel engine

exhaust.

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CONCLUSION

THUS, BY USING TEG, THE WASTE HEAT CAN BE

USED TO GENERATE ELECTRICITY.

SIMULATIONS AND EXPERIMENTS HAS BEEN

CONDUCTED AND MORE EFFICIENT SYSTEMS CAN BE

DEVELOPED IN FUTURE WITH NANOCRYSTALLINE

APPROACH.

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REFERENCES:

1. Thermo-electrics: Basic principles and New Materials Development by Nolas, Sharp and Goldsmid

2. Thermoelectric Refrigeration by Goldsmid

3. Thermodynamics by Callen. Sections 17-1 to 17-5

4. Abram Joffe, “The Revival of Thermoelectricity,” Scientific American, vol. 199, pp. 31-37, November 1958.

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