Turbines, Engines, and Fuel Cells(and also Thermoelectrics!)

Technology of Energy

Seminar 3

Presented by Alex Dolgonos and Jonathan E. Pfluger1

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Thermoelectric Materials

Jonathan E. Pfluger

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Why Energy?

1. https://www.llnl.gov/news/americans-using-more-energy-according-lawrence-livermore-analysis

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Energy Lost is a Big Deal 2004 – U.S. DOE1

Almost 2 Quads of energy could be recovered from industrial heat waste

50-60% of energy is rejected 55 Quads = 58 EJ = 482.6 BILLION gallons of gas 1526 gallons for each American 36.35 barrels/person at $53/barrel = $1926

1. Pellegrino J. et al., ACEEE Summer Study on Energy Efficiency in Industry, ACEEE/DOE (2004)

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What about the environment?

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What are Thermoelectric Generators? Convert heat directly

to electricity Applications in:

Power generation Solid-state

refrigeration Solid-state heating

Benefits: Modular devices Small form factors No moving parts

Wikimedia Commons

Disadvantages: Low efficiencies Toxic elements Expensive/rare elements

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Applications Power Generation

Radioisotope Thermal Generators Waste Heat Recovery

Consumer Geothermal

Active Cooling/Warming Localized Cooling

CPUs Biological Specimens

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Extraterrestrial Applications

1. Google Image Search (left to right): Voyager 1, Mars Curiosity

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Extraterrestrial Applications

1. http://thermoelectrics.matsci.northwestern.edu/thermoelectrics/history.html

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Radioisotope Thermoelectric Generator (RTG)

1. Google Image Search (left to right): Radioisotope thermoelectric generator

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Terrestrial Applications

1. Google Image Search (clockwise from top left): Thermoelectric power, Power pot, Thermoelectric car, Seiko Thermic

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Seebeck Effect

Material B Material B

Material A

V

T T + T

abVα =

ΔT

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P N P N

Power Generation Mode Cooling Mode

Heat Sink Heat Rejection

Active Cooling

I I

Heat Source

Operating Modes of a Thermoelectric

CoupleModules

T. M. Tritt, Science 31, 1276 (1996) www.marlow.com

TE Couple and Module

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Figure of Merit :

High Seebeck coefficient α/S: Energy per K (μV/K) High electrical conductivity σ Low thermal conductivity κl

TS

ZTle

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Improving Thermoelectrics Through Phase Separation

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Balance of Parameters

1. Snyder, Nature 7, 105 (2008)

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Typical Materials

1. Snyder, Nature 7, 105 (2008)

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Areas of Research Bulk

Easily scalable Methodic progress

Nano Novel properties Maximum manipulation of scientific theory

Organic/Oxide Advantageous properties Earth-abundant materials Form factor

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Recent Advancements Northwestern – SnSe1

ZT ~ 2.6 at 923 K

Caltech – PbTe2

ZT ~ 1.8 for PbTe1-xSex

1) Zhao, L.D. et al., Nature 508, 373 (2014)2) Pei, Y.Z. et al., Nature 473, 66 (2011)

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Cost Prohibits Breadth

1. S. LeBlanc et al., Renewable and Sustainable Energy Reviews 32, 313 (2014)

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Scale-Up Concerns

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Outlook Thermoelectric modules show potential

Efficiency concerns for widespread use Materials concerns

Abundancy Cost

1. Vining, C.B., Nature Materials 8, 83 (2009)

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Questions?

1. Google Image Search (left to right): European Telco Orange Power Wellies, Power Felt

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(2)

Improving the ZT of PbTe

Na added to dope PbTe p-type

PbS nanostructures are formed in PbTe by phase separation

Nanostructures improve ZT by reducing κlat

Adding Na

(1)

(3)

Adding PbS

(4)

1) Pei, et al., Eng. Environ. Sci. (2011).2) Leute and Volkmer, Z. Phys. Chem.

(1985).

3) Girard, et al., Nano Lett. (2010).4) Girard, et al., JACS (2011).

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Turbines, Engines, and Fuel Cells

Alex Dolgonos

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Alternator Mechanical Energy Electrical Energy Faraday’s Law of Induction

dt

dN B

Generated Voltage

# of Coils

Rate of Change in Magnetic Flux

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Carnot Engine

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Carnot Engine

Hot Reservoir(T = THot)

Magic Box

Cold Reservoir (T = TCold)

Heat In

Heat Out

Useful Work

Hot

Cold

T

TEfficiency 1

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Pressure-Volume Diagram

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Power Cycles Rankine Cycle (steam turbines)

Brayton Cycle (gas turbines)

Combined Cycle (both!)

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Rankine Cycle (Steam)

1.Pump

2.Boiler

3.Turbine

4.Condenser

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Improvements

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Brayton Cycle (Gas)

http://cset.mnsu.edu/engagethermo/components_gasturbine.html

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Gas Turbine Schematic

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Regeneration

1. http://www.wiley.com/college/moran/CL_0471465704_S/user/tutorials/tutorial9/tut9n_parent.html

http://www.pandafunds.com/assets/img/combined_cycle_layout_diagram.jpg

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Combined Cycle

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Combined Cycle1. Fresh air intake

2. Combustor

3. Air compressor

4. Expansion gas turbine

5. Generator

6. Turbine exhaust

7. HRSG

8. Exhaust stack

9. Superheated steam

10. Steam turbine

11. Transformer

12. Electrical grid

13. Steam condenser

14. Cooling tower

15. Boiler feed water pump

16. Boiler feed water

17. Natural gas fuel

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Projections Coal: 37%32% Natural gas:

30%35%

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Jet Turbine (Turbofan)

A. Low pressure spool

B. High pressure spool

C. Stationary components

1. Nacelle

2. Fan

3. Low pressure compressor

4. High pressure compressor

5. Combustion chamber

6. High pressure turbine

7. Low pressure turbine

8. Core nozzle

9. Fan nozzle

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Rolls Royce Trent 900

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Turbine Blade Technology

2500°F!!! Nickel-based superalloys Thermal barrier coatings Processing improvements Cooling

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Internal Combustion Engines Standard 4-stroke engine

Diesel engine

Surprise engine

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Otto Cycle

IntakeCompressionPowerExhaust

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Partial Power Problem

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Partial Power Problem

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Partial Power Problem

Power is controlled by throttle opening Lower power Higher vacuum Lower efficiency

Solutions Smaller engine

Turbochargers HEVs

Deactivation of cylinders More gears or CVT

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Running Lean

http://www.britannica.com/EBchecked/topic/290504/internal-combustion-engine

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Diesel Engines

No spark required—fuel injection No partial power

problem

High T for self-ignition More particulates More NOX

Particulate filters Catalytic reducers NOX adsorbers Low-sulfur fuel (clean

diesel)

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Case Study: Wankel (Rotary) Engine

Fewer moving parts High reliability High power:weight

Sealing problems Lower fuel efficiency Lubricating oil—higher

running costs

http://pesn.com/2011/04/14/9501810_Wave_Disk_Engine_Sips_Fuel/

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Wave Disk Engine

Spinning motion causes shock waves

Shock waves cause combustion

Combustion drives blades

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Wave Disk Engine

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O2-

O2-

Fuel Cells

ENERGYOHOH 222 22

O

O

ee e e

OH

H

OH

H

H

H

H

H

ee

e e

Cathode Electrolyte Anode

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Fuel Cells

54Brett, et al., Chem. Soc. Rev., 37 (1568-1578) 2008

No combustion Not limited to Carnot

efficiency No moving turbine engines

Maximum efficiency = 83% Fuel cell vehicles

Tank-to-wheel efficiency = 45%

Where does the H2 gas come from? Methane gas Water splitting Plant-to-wheel efficiency

22% (compressed H2)

17% (liquid H2)

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Solid Oxide Fuel Cells

High Efficiency Solid State No Moving Parts High Temp (800-1000 °C)

Fuel flexibility Expensive materials Quicker degradation Need materials with high

conductivity at lower temp

ENERGYOHx

COOx

CH x

222 2

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Solid oxide fuel cells 76 patents

Electrode and electrolyte materials

Interconnects Device architecture

$400 million in VC funding 50% efficient 8.6 years break even

period

Case Study:

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Case Study:

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Questions?

Internal Combus-tion Engine

Gas Turbine Steam Turbine Combined Cycle Fuel Cell0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

19%

40% 42%

60%

83%

Co

nve

rsio

n E

ffici

en

cy

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Alternator Mechanical Energy Electrical Energy Faraday’s Law of Induction

dt

dN B

Generated Voltage

# of Coils

Rate of Change in Magnetic Flux

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Rimac Automobili: 877 hp, 115 kg

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Rimac Automobili: Concept_One

1088 hp0-100 km/h (0-62 mph) in 2.8 s