Trade-off in Thermoelectric Generator design for vehicle application - - PowerPoint PPT Presentation

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www.DLR.de Chart 1 > K. Oetringer 2015-08-11 > K. Oetringer 2015-08-11 Trade-off in Thermoelectric Generator design for vehicle application ECM 2015 Aberdeen, 2015-08-11 Institute of Vehicle Concepts K. Oetringer M.

SLIDE 1

> K. Oetringer • 2015-08-11 > K. Oetringer • 2015-08-11

Trade-off in Thermoelectric Generator design for vehicle application

ECM 2015 Aberdeen, 2015-08-11 Institute of Vehicle Concepts

K. Oetringer M. Eng.
M. Kober Dipl. Ing. (FH)

www.DLR.de • Chart 1

SLIDE 2

> K. Oetringer • 2015-08-11

Outline

Introduction
Motivation
Basics
TEG Evolution at DLR
Optimization
Design-Point
Simulative Results
Validation by Measurement
Outlook

www.DLR.de • Chart 2

SLIDE 3

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 3 1) Treffinger P., Häfele Ch., Weiler T. DLR e.V. Stuttgart; Eder A., Richter R., Mazar B. BMW Group München: Energierückgewinnung durch Wandlung von Abwärme in

Nutzenergie. 2008 VDI Tagung „Innovative Fahrzeugantriebe“, Dresden

About 2/3 of the chemical energy is transferred to heat

Motivation for waste heat recovery Basic combustion engine

SLIDE 4

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 4

thermal diffusion of electrons respectively

holes to cold side

Electric potential is proportional to ΔT:
Dimensionless figure of merit ZT:
Efficiency TE:

S Seebeck-coefficient

heiß kalt

n p +

Kühlmittel Abgas heiß kalt

n p +

Kühlmittel Abgas

T S ZT  



h k h k h in el

T T ZT ZT T T T Q P         1 1 1   T U S  

σ electrical conductivity Κ thermal conductivity T temperature

Basics of thermoelectricity

SLIDE 5

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 5

Electric potential is proportional to ΔT:
Dimensionless figure of merit ZT:
Efficiency TE:

S Seebeck-coefficient

heiß kalt

n p +

Kühlmittel Abgas heiß kalt

n p +

Kühlmittel Abgas

T S ZT  



h k h h h k h in el

T T T ZT T T T Q P 2 2 4 1         

T U S  

σ electrical conductivity Κ thermal conductivity T temperature

Basics of thermoelectricity in application

SLIDE 6

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 6

SLIDE 7

> K. Oetringer • 2015-08-11

Outline

Introduction
Motivation
Basics
TEG Evolution at DLR
Optimization
Design-Point
Simulative Results
Validation by Measurement
Outlook

www.DLR.de • Chart 7

SLIDE 8

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 8

electrical TEG input power ( ) back pressure / cooling of exhaust ( ) cooling load ( ) (el. power for cooling water pump and cooling fan, quick heat-up phase) rolling resistance ( ) (weight increase)

P 

Optimize the benefit for the application

SLIDE 9

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 9

Choosing a Design-Point Basic for Vehicle testing => WLTC

SLIDE 10

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 10

Choosing a Design-Point Which Design-Point contains most energy?

15 g/s 400°C possible Design-Point

SLIDE 11

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 11

Choosing a Design-Point Which Design-Point contains most energy?

15 g/s 400°C possible Design-Point

SLIDE 12

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 12

Choosing a Design-Point Which Design-Point contains most energy?

15 g/s 400°C ⋅ ⋅

: Energy contained by Design Point
: usable Massflow

: heat capacity of exhaust

: usable Temperature
: coldside Temperature of TEG

possible Design-Point

SLIDE 13

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 13

Choosing a Design-Point Which Design-Point contains most energy?

Design-Point: 17g/s 855 K

SLIDE 14

> K. Oetringer • 2015-08-11

weight < 8 kg (without bypass)
volume < 3 dm³ (without bypass and diffusers)
el. peak power > 400 W
el. power at Design-Point > 160 W
gravimetric power density > 50 W/kg
volumetric power density > 133 W/dm³

www.DLR.de • Chart 14

Simulative results Characteristics of the optimized TEG

SLIDE 15

> K. Oetringer • 2015-08-11 www.DLR.de • Chart 15

Measured results Validation of simulation

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> K. Oetringer • 2015-08-11 www.DLR.de • Chart 16

Measured results Validation of simulation

0,00 5,00 10,00 15,00 20,00 25,00 300,0 350,0 400,0 450,0 500,0 550,0 600,0 650,0 700,0 750,0 800,0 1 2 3 electric power TEM2 [W] temperature [K] Design‐Point maximum Point Th_TEM2 [K] Tc_TEM2 [K] Th_sim [K] Tc_sim [K] P.el_TEM2 [W] P.el_sim [W]

SLIDE 17

> K. Oetringer • 2015-08-11

Outline

Introduction
Motivation
Basics
TEG Evolution at DLR
Optimization
Design-Point
Simulative Results
Validation by Measurement
Outlook

www.DLR.de • Chart 17

SLIDE 18

> K. Oetringer • 2015-08-11

Philosophy to success:
Maximizing the benefit for OEM and Driver

=> taking into account negative effects

Not maximizing the el. power output
Reached goals:
Successful integration of high temperature modules
Validation of thermal simulation
Outlook:
Dynamic simulation to simulate a whole driving cycle
Improve / research at high temperature modules

www.DLR.de • Chart 18

Outlook / Summary

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> K. Oetringer • 2015-08-11 www.DLR.de • Chart 19

Potentials
Measuring vehicle
Materials
Concept development
Simulation
Functioning mock up
Validation

Project aim: Developing a new kind of Thermoelectric Generator increasing the efficiency of Range Extender and Hybrid Vehicles Ministry of Finances and Economics Baden-Württemberg

The Project RExTEG

SLIDE 20

> K. Oetringer • 2015-08-11

Thank you for your attention!

Institute of Vehicle Concepts

Pfaffenwaldring 38‐40 70569 Stuttgart Kerstin Oetringer M. Eng. Phone: 0049 ‐ 711 6862 ‐516 kerstin.oetringer@dlr.de www.DLR.de/fk