thermoelectric applications thermoelectric...

Daniel CHAMPIER applications de la thermoélectricité GDR Thermoélectricité 2014 1

Thermoelectric applications

Thermoelectric generators

Université de Pau et des Pays de l'Adour France

Laboratoire des Sciences de l’Ingénieur Appliquées à la Mécanique

et au Génie Electrique (SIAME EA4581),

Fédération IPRA FR2952

CHAMPIER Daniel


Thermoelectric (TE) Generators TEG

Heat

Generator Heat

sink

TE modules

Electrical power

(<5%)

exchanger exchanger

Electronic

converter

Storage Battery

convert directly a very small part of the heat moving through them into electricity

Module efficiency

.TEWe T 1 zT 1

TcQh Th 1 zTTh

Th Tc Tsh Tsc

.TE

H C TE

RT Ts

R R R

efficiency, generator maximum power

.

. . .Max 2 2elec

NSW T

8L

Dependence upon the temperature

difference across the thermoelements

Construction :

number of thermoelements

cross-sectional area

length of each element.

‘‘power factor’’ :

type of TE material

Maximum Power

DC DC


3 International Energy Agency publication :2013 Keyworld energy statistic

World total final consumption from 1971 to 2011

by fuel (Mtoe)

***Other includes geothermal, solar, wind, etc

1Toe=tonne of oil equivalent =41.8 GJ =11.6 MWh = 1 Tep (français)


4 Gail Tverberg http://ourfiniteworld.com/2012/03/12/world-energy-consumption-since-1820-in-charts


173,000 terawatts

2014 Perez Massachusetts Clean Energy Center

Energy is not a problem

Sustainability is the problem

<0.00001 TW.y

TEG

y

Ocean Thermal Energy

0.005 TW.y

1 Billion cars with

a 250W TEG

I have a dream

Yes we can


6

Roadmap for climate and energy policies

2008 European Concil new environmental targets : "three 20 targets”

by 2020

To reduce emissions of greenhouse gases by 20%.

To increase energy efficiency to save 20% of EU energy consumption

To reach 20% of renewable energy in the total energy consumption in the EU.

January 2014 European Concil new environmental targets

by 2030

To reduce emissions of greenhouse gases by 40%.

To continue improvements in energy efficiency

To reach 27% of renewable energy in the total energy consumption in the EU.


7

Some Efficiency

. L’objectif « 20-20-20 » vise pour 2020 à :

Diminuer de 20 % les émissions de Gaz à

Effet de Serre (GES) par rapport aux

missions de 1990 ;

Réduire de 20 % la consommation

d'énergie par le biais de l'amélioration de

l'efficacité énergétique;

Atteindre 20 % d'énergies renouvelables

dans le bouquet énergétique.

Efficiency in Electricity Generation 2003

Union of the electricity industry

2013


The carbon footprint of Energy-Technologies


TE efficiency

.TEWe T 1 zT 1

TcQh Th 1 zTTh

Thermoelectricity has a chance only where other forms of energy production

are not cost effective.

Thermoelectricity : no chance for big power plant

0 50 100 150 200 250 3000

5

10

15

20

25

30

35

40

45

50

difference of temperature Th-Tc K

eff

icie

nc

y %

Carnot efficiency

ZT=3

ZT=2

ZT=1

ZT=0.8

ZT=0.5


Classification of generators

• recovery of thermal energy lost: optimization of wasted heat

• production in extreme environment: sources dedicated to TEG

• decentralized power generation: renewable energy sources

• microgeneration: all heat sources are acceptable

• thermoelectric solar: energy source : the sun.


Waste heat

1 quad=2.93 1011kWh=1.055x1018J


Secteur automobile

Thermoelectric technology

for automotive Waste Heat Recovery

Prototypes :

- FIAT

- FORD

- GM

- BMW

- Amerigon

- Renoter (Renault truck Volvo …)


Thermoelectric technology for automotive Waste

Heat Recovery

Opportunity for Waste

Heat Recovery with

Thermoelectrics


Thermoelectric technology for automotive Waste

Heat Recovery

Sankey diagram for diesel vehicle

light duty trucks

3% efficiency

mean 0.9kW


Economic context European Union

Emission target for passengers cars

130g/km for 2012

drastically reduced to 95g/km for 2020

Emission target for light duty trucks

175g/km for 2014

135g/km for 2020.

Fine and penalties to be paid by car

manufacturers that exceed EU CO2 limits

20€ per exceeding gram starting from 2012

95€ per exceeding gram starting from 2020

New CO2 emission performance standards


Comparison Alternator - TEG

400-500Wel means 6-7g/km CO2 reduction (Fiat Research Center)

small-medium gasoline engine at motorway driving condition is

characterized by a thermal power, in its exhaust gases, of 10kW at 600°C,

4-5% system conversion efficiency, which can be feasible with ZT=1-1.2

is enough to guarantee 400-500 Wel.

Conversion efficiency from fuel chemical energy to mechanical energy 25-27%

alternator efficiency from mechanical to electrical energy 60%

conversion efficiency from fuel chemical energy to electrical energy 15-16%

Electricity produced by alternator

Electricity produced by TEG


Automotive Requirements for a TE Generator

•Backpressure limit in TEG

•Exchanger must not disturb too much exhaust gases: pressure

drops very low (tens of a few millibars).

•Temperature limit for TE materials (add bypass for exhaust gases)

•Durability test requirements

•Assembly requirements

•Control and sensor requirements

•Power conditioning (DC/DC converter)

•Recycling

•Price and Performance

Requirements


Alternator Replacement by a TEG

A TEG must be able to provide necessary power ( about 3kw 220A

14V) to the vehicle under extremely challenging conditions:

• Idle

• City drive cycle (Start-Stop)

• +50°C to -30°C ambient conditions

• Full accessory loads, including current spikes

• Reduce TOTAL fuel consumption, weight, and cost compared to

an alternator/battery system


Ford

Half-Heusler + Bi2Te3segmented TE elements

Anticipated power: ~500 Watts (peak)

TEG on a Ford Fusion with 3.0L V-6 Engine

the exhaust


Ford Packaging for Prototype TEG

TEG

FlexCoupling

Underfloor Catalyst

To Exhaust

To Exhaust


FORD

C. Maranville “ Thermoelectric opportunities for light-duty vehicles.” Ford Motor Company 2012


FORD : TEG performances for a 100km/h cruise

C. Maranville “ Thermoelectric opportunities for light-duty vehicles.” Ford Motor Company 2012

A bypass is necessary to protect the TEG

Anticipated power: ~500 Watts (peak) !!!

Temperature of gas

Welec

105km/h


General Motor

2011Meisner advanced thermoelectric material and generator technology for automotive waste heat at GM.pdf


GM project may 2011

This module could capture waste heat in car's exhaust and convert it to energy, improving fuel economy in a

Chevy Suburban by 3%.

Computer models show the device could generate 350 to 600 watts for city and highway driving, respectively.

General Motors Thermoelectric Generator

Vehicle Selection : Chevy Suburban


Finalize design of prototype TEG

only Bi2Te3 modules by-pass valve set point temperature

for the heat exchanger is about 250°C.


GM : Instrumented TEG and Results

Temperature of the heat exchanger is

250°C for a temperature of exhaust gas

around 400°C


150°C



Temperature variation along the Teg //

to the exhaust gas flow is significant

Front 250° Middle 178° Rear 148°

Temperature variation transverse to

the exhaust gas flow is low < 3°C


Coolant

50°C

1,3 W avec

un HiZ20

209$ !!!!

150°C

11 W avec

un HiZ20




Open circuit voltage are consistent with a 50°C smaller ΔT than

measured between the heat exchanger and the coolant

Computer models show the device could

generate 350 to 600 watts


G. P. Meisner, “Skutterudite thermoelectric generator for automotive waste heat recovery,” in 3rd Thermoelectrics Applications Workshop 2012

GM : future work

Expected Output power 425 Watts !

Improved skutterudite TE materials

Refine TEG design :thermal and electrical interface, bonding …

Electrical power conditioning (avoid impedance mismatch)

First experiment 19W with few modules and small ΔT

extrapolated to 235 Watts in optimum conditions


BMW

BMW 2008

BMW 535i (US)

Bi2Te3TEG (2007)

High-temperature TEG

Pmax=300W (2009)

2012 Boris Mazar State of the Art Prototype Vehicle with a Thermoelectric Generator

Bi2Te3

Bi2Te3

PbTe


BMW

BMW 2008

BMW 535i (US)

Bi2Te3TEG (2007)

High-temperature TEG Pmax=300W (2009)

2011 Dr. Andreas Eder Efficient and Dynamic –The BMW Group Roadmap for the Application of Thermoelectric Generators


Possibles locations for TEG

Integration into the EGR (Exhaust Gas

Recirculation) for a diesel engine:

Advantages

Easier to integrate (existing exchanger)

Control for mass flow (EGR valve)

Cooling water already there

Disadvantages

Reduced recuperation potential (5 à 35%)

Integration in the exhaust system:

Advantages

•Highest recuperation potential

Disadvantages

•Exchangers : high integration effort

•Connection to cooling system

•Bypass : (flat possible but expensive)

A. Eder, BMW group, thermoelectrics applications 2011

Exhaust Gas Recirculation reduces

NOx emissions by reducing the

combustion temperature in Diesel

engines.

EGR works by recirculating a portion

of an engine's exhaust gas back to

the engine cylinders.

Gas must be cooled


BMW

The EGR-TEG unit consists of a TEG

section and a conventional cooler section.

conventional

cooler section.

TEG section


Renault Trucks, Volvo … Projet RENOTER

“Récupération d'ENergie à l'échappement d'un mOteur par ThERmoélectricité”


Renault Trucks, Volvo

Choice of Silicide's

- N-type : Mg2Si

- P-type : MnSi1.77

Advantages disadvantages

Non-toxic materials Moderate ZT

Light density (2-4) Mg2Si type P not

available

Abundant raw materials Current doping of Mg2Si

in project

Support high exhaust

temperature (> 600°C)

P and N have different

mechanical properties

Successful lab. production of the legs for

the project prototype

2012 Luc Aixala RENOTER project presentation


Renault Trucks Joint Company -Volvo Group

•original Design of TEG compatible with different TE materials

•aim 1kW (Truck) and 300W (car) possible this year (2011)

Results 350W 250W

Renoter2 10 000 cars equipped for 2018 100 000 for 2020


HeatReCar first light commercial vehicule equipped with a TEG

Vehicle

IVECO Daily, 2.3l Diesel engine

Design reference condition Vehicle @130kph

Exhaust gas temperature: 450°C

Gas flow : 70g/s (max torque), 140g/s (full load)

Target performance TEG electrical output 1kW

D. Magneto 3rd International Conference Thermal Management for EV/HEV Darmstadt 24-26 June 2013




Cross Flow architecture.

Material considered

•TAGS

•Segmented Bi2Te3-PTe

•Skutterudites: developed and manufactured at

Module level

•Bi2Te3: used for the full scale prototype

manufacturing with specific Module design

16 x 16 mm




Core size 500x100x100mm

Core weight 4kg

TEG architecture.

Air tank outlet

Air tank inlet .

By pass valve

Water

tank

Water

tank




Hot gaz flow: 90g/s

ΔP hot gaz: 30mbar

T hot gaz: 450°C

Cold liquid flow: 1200l/h

ΔP liquid flow: 0.15 bar

T cold flow 60°C

U: 32.1V

I : 15A

P: 482W

TEG performances on the test bench




TEG on board installation On board vehicle results summary

the WLTP test is expected to replace the

European NEDC procedure for testing of

light-duty vehicles

•Cycle NEDC, the TEG electric output is provided

mainly in the extraurban part of the Cycle.

•Cycle WLTP, the System reached a peak of about

220 W.

•In the last part of WLTC TEG power is sufficient

to provide the on-board electric need, thus

completely replacing the alternator

• 4% fuel economy improvement over the WLTP

cycle has been achieved

www.dieselnet.com/standards/cycles/wltp.php


GENTHERM ex AMERIGON ex BSST + BMW et Ford

Cylindrical TEG

TEGs were installed in a BMW X6 and a Ford Lincoln MKT with at least

450W of power output achieved in road tests for both vehicles.

D. Crane, “Thermoelectric generator performance for passenger vehicles” 2012


GENTHERM ex AMERIGON ex BSST + BMW et Ford

Bell, L.E. and Crane, D.T. and LaGrandeur, J. and van Heerden, D,

Thermoelectric-based power generation systems and methods, US Patent App. 12/843,804

cooling fluid

cold side

shunt

Hot side

shunt

ceramic

honeycomb Hot Exhaust

gas


AMERIGON BSST (BMW et Ford)

Tenneco’s booth at the 2013 Frankfurt IAA Motor Show

Hot side

Larger area

Best

exchange


AMERIGON BSST (BMW et Ford)

Tenneco’s booth at the 2013 Frankfurt IAA Motor Show


Aircraft Thermoelectric Applications

Aircraft engine waste heat harvesting has large potential payoffs

How can Thermoelectric Contribute?

Turboprop Turbine à gaz + hélice

Turboshaft Turbine à gaz + arbre de transmission

Turbofan Moteur à réaction

2009 James Huang,Boeing Research & Technology

Fuel Reduction

Preliminary analysis showed that 0.5% or more fuel reduction is achievable

Operating Cost Reduction

Average monthly fuel costs for U.S. commercial planes is $2.415B for the first

4 months of 2009 (Source: EIA)

A 0.5% fuel reduction : $12M monthly operating cost reduction

Advantages Disadvantages

•Provides electrical power from waste heat – no fuel

burn and no moving parts

• Operates over the entire aircraft flight envelope

• Operates independent of engines and does not

affect engine operations

•New technology and unproven

•Cost & efficiency; further development is needed

•Power output limited by available waste heat, space,

device efficiency.

Watt per kilo?

Acceptable 0.15 kW/kg

Tuyère adiabatique hélicoptère

Champier : 0.04kW/kg


Usage of Thermoelectric Generators on Ships

Ship transport generates a large amount of

waste heat

main engine (8-15 MW)

(heavy fuel oil)

auxiliary engines

incinerator

(waste oil : sludge representing 2% of oil

consumption of the main engine)

Workers at heavy cost .

Cold sink between 5°C and 28°C

available (seawater)

no problem with space and weight

Wasted heat used for

heating of heavy fuel oil

•Heating of accommodation areas

•freshwater generation

Work intermittently

Working time : 12h to 20h /day

Steam engine :

Needs a worker at

start and stop : heavy

cost

Thermoelectric

genrator

Kristiansen : incinerator 850kW, calculation : 38kW electric cost 2,7US$/W.


Usage of Thermoelectric Generators on Ships

Significant potential:

powerful engines

Cold source available

The weight is not a constraint

costly maintenance

Use of the systems developed for the

automotive or aircraft without weight

constraints.


Waste heat recovery : conclusion

Automotive

Alternator + TEG : imminent

Replacement of alternator : challenge

Airplanes

More research is necessary …

ships

Promising

Car 20€/kg Pizza 30€/kg!


Electricity production in extreme environment

critical applications: a power source extremely reliable over very long periods.

extreme climatic conditions:

• very hot

• very cold

• very wet

• very dry.

Maintenance as low as possible

• helicopter access

•several hour trip

Maintenance does not exist in the case of space expeditions.

operation in a vacuum

vibrations.

insensitive to radiation

The cost of watt is not essential


Space applications

First use of a thermoelectric generator (Pb -Te) : 1961

navigation satellite Transit (1961) of the U.S. Navy.

SNAP-3 (Space Nuclear Auxiliary Power)

Electrical power~2,7 watts

worked for more than fifteen years


Space applications

RTG Radioisotope Thermoelectric Generator

Radioisotope Thermoelectric Generators, or RTGs convert the heat generated by

the decay of plutonium-238 (plutonium dioxyde 238PuO2) fuel into electricity using

devices called thermocouples.

http://solarsystem.nasa.gov/rps/rtg.cfm

GPHS : General Purpose Heat Source module

238Pu fuel pellet


Space applications

T. Caillat et al 23rd rd Symposium on Space Nuclear Power and Propulsion STAIF 2006Jet Propulsion Laboratory/California Institute of Technology


Space applications

T. Caillat et al 23rd rd Symposium on Space Nuclear Power and Propulsion STAIF 2006 Jet Propulsion Laboratory/California Institute of Technology


Space applications


Cassini’ RTG before mounting


Space applications


Curiosity’s Radioisotope Thermoelectric Generator


Space applications

Radioisotope Thermoelectric Generator RTG

Electric Power at beginning

of mission per RTG

Number of RTG

Mission destination year design

lifetime lifetime

Space Nuclear Auxiliary Power SNAP-3 PbTe

2,7 Watts 1 Transit Navigation satellite 1961 15 years

SNAP-19B RTG PbTe-Tags 28.2 Watts 2 Nimbus III meteorological satellite 1969

SNAP-19 RTG PbTe-Tags

42.6 Watts 2 Viking 1 Mars landers 1975 90 days 6 years

2 Viking 2 Mars landers 1975 90 days 4 years

40.3 Watts 4 Pioneer 10 Jupiter, asteroid belt 1972 5 years 30 years

4 Pioneer 11 Jupiter Saturn 1973 5 years 22 years

SNAP-27 RTG PbSnTe

70 Watts Apollo 12, 14,

15, 16 , 17 Lunar Surface

1969-72

2 years 5-8 years

Multi-Hundred Watt (MHW) RTG SiGe

158 Watts 3 Voyager 1 & 2 edge of solar system 1977 still operating over 30 years

General Purpose Heat Source (GPHS) RTG

SiGe 292 Watts

2 Galileo Jupiter 1989 14 years

3 Cassini Saturn 1997 still operating after 14 years

1 Ulysses Jupiter 1990 21 years

1 New Horizons Pluto, Kuiper Belt 2006 still operating after 6 years

Multi-Mission Radioisotope Thermoelectric Generator

MMRTG PbTe-Tags 110 Watts 1 Curiosity

Mars Surface 5 Aug 2012

2011 Expected 14

years


Space applications

Radioisotope Thermoelectric Generator

• compact

• Continuous power sources

• Used in deep space for several decades

• reliable

• Use nuclear fuel relatively easy to manipulate Curium-244

and Plutonium-238

• Materials used: PbSnTe, PbTe, TAGS, SiGe

Conclusion

Current research:

Improved performance of materials: reduced thermal conductivity of the

network

Zintl, skutterudites, couples segmented.


Remote Power Solutions

REJECTED

HEAT

500 Watts 24 Volts

Natural Gas 48m3/day

Propane 76L/day or 38kg/day

COOLING

FINS

EXHAUST

OUT

LOAD

FUEL IN

T

E

G

F

L

A

M

E

Oil or gas pipelines

Well sites

Offshore platforms

Telecommunications sites

Communications systems

….

Critical application requiring highly reliable power

Low maintenance required

Long life

Extreme climatic conditions (hot, cold, wet, dry)

Remote locations

Propane 38kg/day

Heating Value 50MJ/kg Energy per day= 1900MJ=527kW.h

500 W electric Energy per day= 12 kW.h Efficiency : 2.2 %

April 1, 2014

Engine generator: efficiency 16 % and price …!



500 Watts 24 Volts

Natural Gas 48m3/day

Propane 76L/day or 38kg/day

Pipeline: 550 watts

communications system

Andes Mountains, Chile

Off shore: 200 watts

communications and safety

equipement, multiple systems

- Thailand

Critical application requiring highly reliable power

Low maintenance required

Long life

Extreme climatic conditions (hot, cold, wet, dry)

Remote location Telecommunications:50 watts

helicopter access only,

emergency communications system

- Rocky Mountains, Canada

Pipeline:

5000 watts for SCADA

communications and cathodic

protection of gas pipeline - India

Niche market for TEG



electrical output of a Model 5060 TEG

Maximum Power for an

electrical load between

0.4 and 0.9 ohm


Biomass stoves

Combined Heat and Power (CHP)

Decentralized electricity generation

Developing countries

Biomass primary energy source

(cooking, heating, domestic hot water)

Developed countries

Connection to the network is not always

economically attractive


• Biomass energy is used for basic needs : cooking and heating

• They needs electricity for light, cellular phone and radio

• Biomass is burnt through open fire stoves – low efficiency forest destruction and global warming contribution

– high emissions of air pollutants health damaging

• “Planète Bois” is developing an improved multifunction biomass fired stove. combustion chamber is designed to achieve almost complete combustion of wood

A fan is necessary to increase the air/fuel ratio

Smoke can be extracted with a horizontal pipe avoiding the building of a vertical chimney

• Connecting these households to the power grid cost of building new landlines from US$300 to more than US$4000

cost of distribution of electricity from US$0.07 to US$5.1 per kWh

• thermoelectric generators are cost-effective options for these specific off-grid households.

1.2 billion people

without electricity

in developing countries

Thermoelectric power generator for Biomass

Stoves


Review of thermoelectric generators

for cooking stoves

Author Heat sink (cold side) Type of module * Power per

module

Nuwayhid 2003 Natural air cooling Peltier 1W

Nuwayhid 2005 Natural air cooling Seebeck 4.2W

Nuwayhid 2005 Heat pipes cooling Seebeck 3.4W

Lertsatitthanakorn 2007 Natural air cooling Seebeck 2.4 W

Mastbergen 2007 Forced air cooling (1W) Seebeck + 4W regulated

“BioLite” 2009 Forced air cooling (1W) Seebeck + 2 W

Champier “TEGBioS “ 2009 Water cooling Seebeck 5W

Champier “TEGBioS II“ 2010

Water cooling

Seebeck

9.5W

7.5 W regulated

Rinalde 2010 Forced water cooling (?W) Seebeck 10 W

O'Shaughnessy 2014 Forced air cooling (?W) Seebeck 5.9W regulated

Bismuth Tellurid (Bi2Te3)

* Peltier :

The temperature difference is limited due to the maximum temperature supported by the solder

The geometry is optimized for cooling and not for power generation.

* Seebeck

The hot side work at a temperature as high as 300°C continuously.

The geometry is optimized for power generation

Heat source : hot gas


Open fire vs cooking stove

Open fire

very low efficiency (5-10%)

emission of harmful black fumes

increase pressure on natural forests

85 % global efficiency

maxi CO level of 200 g/GJ

reduce the fuelwood consumption by two

uses cut branches (length 40 cm, diameter between 4 and 8 cm)

Simultaneous cooking of 2 dishes

Important production of domestic hot water:

showering, cleaning, laundry, dishes.

Cumulus effect: available hot water between 2 sessions

available hot water for morning ablutions.

low temperature radiant heating

mechanical extraction (electric fan) no chimney

less expensive and easier installation

Planète bois

cooking stove

clean household

woodstove

Rocket stove

T-LUD (Top Lid UpDraft)

efficiency (40%) efficiency (35%)


“Planète Bois” Cooking stove and TEG

Biomass stove

A) pyrolyzing chamber

B) hot incoming combustion gas

D) cooking plate

E) water tank 18 liters

F) fan

Electric fan

Pyrolysis

chamber

Mixing zone

(shaker)

Flaming

chamber

Water

tank

TEG

Smoke

box

Forced draft

Primary air

entrance

Secondary air

entrance

Power 6 kW

Domestic hot water production

30L each 30 min

Wood consumption 1,5kg per hour

Outside Dimensions (L,w,h) 110x60x85 cm

Life expectancy 15 years

Average efficiency More than 80% 10 kW wood consumption

2.4 kW are used in heating the water 4.5 kW are used in heating the room and inertia

0.9 kW is used for cooking

The idea is to put the TEG in a cogeneration system which

simultaneously provides electric power and heat for the hot water


“Planète Bois” Cook stoves

Primary air

entrance Secondary air

entrance


TEG for stoves

T2

T1

T3

T8

T4 T5

T9 T7 T6

Heat flow

TE

module

Aluminium heat exchanger

Water tank

Thgi1

Thgo

Tw2

Thgi2

TE modules

Heat exchanger

TE modules

Tank Wall

Thermocouple Aluminum

Water

Water tank

67


Maximum Power Point Tracking Boost converter.

Converter

+ -

Battery

DC

DC TE modules

Heat exchanger

Tank

Hot gas

Water

Vin

Iin

MPPT

Microcontroller

MC9SO8

Vout

Iout

Eoc

Ri

TE

Generator DC/DC convertor Battery + Load

Virtual load

Pulse Width Modulation

Ri

Eoc

T Cold

THot

R v

TE module

Virtual Load

V in

I in

0

1

2

3

4

5

6

7

8

0 1 2 3 4 5 6 7

Po

wer

(

W)

Voltage Vin (V)

Thot=250 ° C Thot=200 ° C Thot=150 ° C Thot=100 ° C

Tcold =50 °C

E oc /2 E oc

Maximum power point Vin est contrôlé par le rapport cyclique dc

Fraction de période pendant laquelle l’interrupteur est ouvert

Vin=Vout (1-dc)=Vbatterie (1-dc)


Maximum Power Point Tracking Boost converter.

Converter

+ -

Battery

DC

DC TE modules

Heat exchanger

Tank

Hot gas

Water

Choix correct de l’incrément de Dc

0,988

0,990

0,992

0,994

0,996

0,998

1,000

0 5 10 15 20

effic

ienc

y

Input Power Pe

Measured efficiency of the MPPT algorithm

Efficiency : Pin/Pmax

Measure Iin

Measure Vin

Calculate Pin

Change duty cycle

Compare with

previous Pin

Vin and Iin change

Measure Iin

Measure Vin

Calculate Pin

Change duty cycle

Compare with

previous Pin

Vin and Iin change

Algorithm Perturb and Observe

On est sur d’être au moins à 99% de la

puissance max

Avec les pertes du convertisseur :90%



Temperatures fluctuate a lot



D) cooking plate


F) fan

Power 6 kW


30L each 30 min




Average efficiency More than 80%



Output Electrical Power : 23.7 W.h

Fan consumption : 15.3 W.h



D) cooking plate


F) fan

Power 6 kW


30L each 30 min




Average efficiency More than 80%

Heat flow

B

Aluminium heat exchanger

Water tank

Thgi1

Tgo

Thgi2

B

A

A

D

C

C


TEG results. Cycle one cooking

1h30min

Day 1

2 cookings

Electrical energy

produced

23.7Wh 47,4Wh

Average electric Power 15.8 W

Fan consumption 15.3Wh 30,6Wh

Extra Use

Use’s exemple*

one phone charge

1 hours of light

1 phone charge almost

4 hours of light

Major Advantage - Wood consumption divided by two

- Healthy (less black fumes)

- More comfort for women

- low CO

* Phone battery of 3.7V, 1050mAh and light consummation of 4W

TE generators are cost-effective solutions for off-grid households with low income.

Cost one sample Big quantity

Aluminium 60€ 30€

electronic part 31€ 15€

TE modules 75€ x6 27€ x 6

TE generator 541€ 207€


Advantages of TEG’s

The advantages of thermoelectric generator are :

It does not need extra energy from the stove.

• It will use the heat flux between the gas and the water tank

• It will only convert a small part into electrical energy.

It is incorporated into the cook stove:

• it requires no electrical link with the outside world, unlike solar panels, or

manipulation of battery.

The maintenance is very light:

• nothing is moving,

• everything is inside the house,

• only the battery needs to be changed at the end of its life.

The generator produces when the stove is on, day and night in good or in rainy

weather (monsoon period) unlike solar panel.

The battery does need to be oversized as each use of the stove recharges the battery

unlike solar system where you need to store energy for the cloudy days.


Today Tomorrow

with TEG

Somewhere in a village


thermoelectric generators for cooking stoves

Biolite

USB

2W 5V


Biolite

HomeStove and CampStove

Ghana

Lake Brassua (Maine)

129$


Combined Heat and Power (CHP) with TEG

Automatic Pellet Furnaces, especially Small Scale Combustion Units

Market

East of Europe and North-America

because of unreliable Electric Power Grids

Stove with TEG 400

Max: 8 kWth, 100 Wel

Air cooling

Boiler with TEG 400

Max: 12 kWth, 300 Wel

Water cooling

Outlook BIOENERGY 2020+


Combined Heat and Power (CHP) with TEG

Module 8cmx8cm

TEG

Biomass CHP

(pellets)

BIOENERGY 2020+

Location Wieselburg 100km from Vienna !

Decentralized production for decentralized utilization

Production of electricity during periods of high heat demand

and low offer of other renewable energies:

• During winter

• Whilst twilight or night

• During times without sun and wind

Fuel heat output: 10 kW

Nominal electric power: 200 - 400 W

• 8 plates, each with 2 modules

• Positioned around flame

• Heated from inside, cooled from outside


Autonomous Gas Heaters

2011 M. Codecasa Design and development of a teg cogenerator device integrated in self standing gas heaters

Heater 8kW

Thot 305°C

Tcold 125°C

Power 7.8W


Energy Harvesting for Low Power Electronics

http://www.micropelt.com

Modern wireless sensor modules require only ~100 W -10mW

Micropelt thermogenerator offers a high density of up to 100

thermoelectric leg pairs per mm2

200 C max.

Electrical:

•Thermo-Voltage: uTEG = 0.14 V/K

•Electrical Resistance: RTEG ~ 350

•Thermal Resistance: Rth = 12,5 K/W

Take a small portion of a lost flow of ‘primary’ energy, and convert it into a small flow of USEFUL

electrical energy.

Every technical process produces waste heat

4.2mmx3.3mmx1mm

5mW is enough for most microsensor

Micropelt MPG-D751



http://www.micropelt.com

Emerson WiHART

Differential Pressure Transmitter

ABB Technology Demonstrator

•Self-powered WirelessHART temperature

transmitter

•Fully integrated thermogenerators

•Powered by Micropelt TEG & boost technology

Applications :

Wireless sensors

Data loggers

Direct valve control

Wireless pneumatic control

Use heat from 15 mm pipe

Output power 3.5mw

at 60°C and ambiant 25°C



www.nextreme.com

thermobility™ wpg-1

wireless power generator

D. Samson, “Aircraft-specific thermoelectric

generator module, 2010

Phase changing material

H2O

40 minutes of electrical

power after take-off !!

Temperature outside -20°

Laird technology


Solar Thermal to Thermoelectricity

Solar Thermoelectricity STEG

5 21001 10 W/m

0.001

q Tk

A L

-1 -11 W.m Kk

100T K

0.001L m

Heat flux through a thermoelectric leg

Solar insulation: ~ 1 000 W/m2

Need to concentrate heat by ~100 times


Solar Thermoelectrics

1000°C

SiGe


Solar Thermoelectrics STEG

Kraemer High-performance flat-panel solar thermoelectric generators with high thermal concentration Nat mat 2011

The developed solar thermoelectric generators (STEGs) achieved a peak

efficiency of 4.6% under AM1.5G (1 kW m−2) conditions.

Photovoltaic: efficiency 20 %


Design of thermoelectric generator


An example of TEG

Hot exchanger

Cold exchanger

87

Thermoelectric modules

Bi2Te3 Thermonamic


Thermoelectric Generator

TEG

Hot fin exchanger Cold exchanger

88


Numerical model

Diagram of a half exchanger

• Standard equations of thermoelectricity, heat

transfers

Steady state

89

Convective exchange correlations


Numerical model

-Electrical equivalent model calculated for each k secondary cutting.

-All parameters are temperature

dependent.

- Newton-Raphson method for convergence.

90


-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

300

320

340

360

380

400

420

440

460

480

500

y (en mètres)

T (

en

K)

T hot gas

Thot wall

Thot couple

Tcold couple

Tcold wall

Tcold liquid

Results and Experiment

Puissance

mesurée (W)

Puissance

estimée (W)

37 W 38,8 W

T TEcouple T system

thermoelectric applications thermoelectric...

Documents