Turbines, Engines, and Fuel Cells
(and also Thermoelectrics!)
Technology of Energy
Seminar 3
Presented by Alex Dolgonos and Jonathan E. Pfluger
1
Thermoelectric Materials
Jonathan E. Pfluger
2
Why Energy?
3
1.
https://www.llnl.gov/news/americans-using-more-energyaccording-lawrence-livermore-analysis
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




4
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)
What about the environment?
5
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:



6
Low efficiencies
Toxic elements
Expensive/rare elements
Applications
Power Generation



Radioisotope Thermal Generators
Waste Heat Recovery


Consumer
Geothermal
Active Cooling/Warming
Localized Cooling




7
CPUs
Biological Specimens
Extraterrestrial Applications
8
1.
Google Image Search (left to right): Voyager 1, Mars
Curiosity
Extraterrestrial Applications
9
1.
http://thermoelectrics.matsci.northwestern.edu/ther
moelectrics/history.html
Radioisotope Thermoelectric Generator
(RTG)
10
1.
Google Image Search (left to right): Radioisotope
thermoelectric generator
Terrestrial Applications
11
1.
Google Image Search (clockwise from top left): Thermoelectric
power, Power pot, Thermoelectric car, Seiko Thermic
Seebeck Effect
Material A
Vab
α=
ΔT
T + T
T
Material B
Material B
V
12
TE Couple and Module
Heat Source
P
N
Heat Sink
I
Power Generation Mode
Active Cooling
P
N
Heat Rejection
I
Cooling Mode
Operating Modes of a
Thermoelectric Couple
T. M. Tritt, Science 31, 1276 (1996)
13
Modules
www.marlow.com
Improving Thermoelectrics Through Phase
Separation
S 2
ZT 
T
e  l

Figure of Merit :

High Seebeck coefficient α/S: Energy per K (μV/K)
High electrical conductivity σ
Low thermal conductivity κl


14
Balance of Parameters
15
1.
Snyder, Nature 7, 105 (2008)
Typical Materials
16
1.
Snyder, Nature 7, 105 (2008)

Areas of Research
Bulk



Nano



Easily scalable
Methodic progress
Novel properties
Maximum manipulation of scientific theory
Organic/Oxide



Advantageous properties
Earth-abundant materials
Form factor
17
Recent Advancements

Northwestern – SnSe1


ZT ~ 2.6 at 923 K
Caltech – PbTe2

18
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)
Cost Prohibits Breadth
19
1.
S. LeBlanc et al., Renewable and Sustainable Energy
Reviews 32, 313 (2014)
Scale-Up Concerns
20
Outlook

Thermoelectric modules show potential


Efficiency concerns for widespread use
Materials concerns


21
Abundancy
Cost
1.
Vining, C.B., Nature Materials 8, 83 (2009)
Questions?
22
1.
Google Image Search (left to right): European Telco
Orange Power Wellies, Power Felt
Improving the ZT of PbTe
(1)

Na added to dope
PbTe p-type

PbS nanostructures are
formed in PbTe by
phase separation

Nanostructures
improve ZT by
reducing κlat
23
1) Pei, et al., Eng. Environ. Sci. (2011).
2) Leute and Volkmer, Z. Phys. Chem. (1985).
Adding
Na
(2)
(3)
(4)
Adding
PbS
3) Girard, et al., Nano Lett. (2010).
4) Girard, et al., JACS (2011).
24
Turbines, Engines, and Fuel Cells
Alex Dolgonos
25
Alternator


Mechanical Energy  Electrical Energy
Faraday’s Law of Induction
# of Coils
d B
  N
dt
Generated
Voltage
26
Rate of Change in
Magnetic Flux
Carnot Engine
27
Carnot Engine
Hot Reservoir
(T = THot)
Heat In
Useful Work
Magic Box
Heat Out
Cold Reservoir
(T = TCold)
28
TCold
Efficiency  1 
THot
Pressure-Volume Diagram
29
Power Cycles

Rankine Cycle (steam turbines)

Brayton Cycle (gas turbines)

Combined Cycle (both!)
30
Rankine Cycle (Steam)
1. Pump
2. Boiler
3. Turbine
4. Condenser
31
Improvements
32
Brayton Cycle (Gas)
33
Gas Turbine Schematic
34
1.
http://cset.mnsu.edu/engagethermo/components_gas
turbine.html
Regeneration
35
1.
http://www.wiley.com/college/moran/CL_047146570
4_S/user/tutorials/tutorial9/tut9n_parent.html
Combined Cycle
36
1.
http://www.pandafunds.com/assets/img/combined_cy
cle_layout_diagram.jpg
Combined Cycle
1.
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
37
Projections

Coal: 37%32%
38

Natural gas: 30%35%
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
39
Rolls Royce Trent 900
40
Turbine Blade Technology

2500°F!!!




41
Nickel-based superalloys
Thermal barrier coatings
Processing improvements
Cooling
Internal Combustion Engines

Standard 4-stroke engine

Diesel engine

Surprise engine
42
Otto Cycle
Intake
Compression
Power
Exhaust
43
Partial Power Problem
44
Partial Power Problem
45
Partial Power Problem

Power is controlled by throttle opening




Lower power
Higher vacuum
Lower efficiency
Solutions

Smaller engine




46
Turbochargers
HEVs
Deactivation of cylinders
More gears or CVT
Running Lean
47
Diesel Engines

No spark required—fuel
injection

No partial power problem

High T for self-ignition


More particulates
More NOX




48
1.
Particulate filters
Catalytic reducers
NOX adsorbers
Low-sulfur fuel (clean diesel)
http://www.britannica.com/EBchecked/topic/290504/i
nternal-combustion-engine
49
Case Study: Wankel (Rotary) Engine

Fewer moving parts



High reliability
High power:weight
Sealing problems


50
Lower fuel efficiency
Lubricating oil—higher
running costs
Wave Disk Engine

Spinning motion causes
shock waves

Shock waves cause
combustion

Combustion drives blades
51
1.
http://pesn.com/2011/04/14/9501810_Wave_Disk_E
ngine_Sips_Fuel/
Wave Disk Engine
52
Fuel Cells
2H 2  O2  2H 2O  ENERGY
e
e
e
e
e
O
O
O
O2O2-
e
O
Cathode
53
Electrolyte
e
H
H
H
H
e
H
H
Anode
H
H
Fuel Cells

No combustion




Not limited to Carnot
efficiency
No moving turbine engines
Maximum efficiency = 83%
Fuel cell vehicles

54
Tank-to-wheel efficiency = 45%
Brett, et al., Chem. Soc. Rev., 37 (1568-1578) 2008

Where does the H2 gas come
from?



Methane gas
Water splitting
Plant-to-wheel efficiency


22% (compressed H2)
17% (liquid H2)
54
Solid Oxide Fuel Cells
x
x 
CH x    1O2  CO2  H 2O  ENERGY
2
4 




High Efficiency
Solid State
No Moving Parts
High Temp (800-1000 °C)




55
Fuel flexibility
Expensive materials
Quicker degradation
Need materials with high
conductivity at lower temp
Case Study:

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
56
Case Study:
57
Questions?
100%
90%
Conversion Efficiency
80%
83%
70%
60%
60%
50%
40%
40%
42%
30%
20%
10%
19%
0%
Internal
Combustion Engine
58
Gas Turbine
Steam Turbine
Combined Cycle
Fuel Cell
59
Alternator


Mechanical Energy  Electrical Energy
Faraday’s Law of Induction
# of Coils
d B
  N
dt
Generated
Voltage
60
Rate of Change in
Magnetic Flux
Rimac Automobili: 877 hp, 115 kg
61
Rimac Automobili: Concept_One
1088 hp
0-100 km/h (0-62 mph) in 2.8 s
62