Transcript Pyroelectric energy harvesting devices

Pyroelectric Energy Harvesting
Devices
Student Design Team:
Trent Borman1, John Etherington2, Thomas Geske1, Joshua Grindeland2
Faculty Advisors & Clients:
Scott Beckman1 and Sumit Chaudhary2
Donor:
Pete Onstad (to foster EE/MSE senior design collaboration)
1
1
Department of Material Science and Engineering; Iowa State University; Ames, Iowa; USA
2
Department of Electrical and Computer Engineering; Iowa State University; Ames, Iowa; USA
MAY14-25
Problem Statement
Convert waste thermal energy to electricity.
Design a system to utilize the pyroelectric
effect in materials with high entropy
transitions.
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Market Survey
• Waste heat is abundant
• No clear industry leader in thermal energy to
electric energy conversion
• Modern high entropy materials exceed bulk
ceramics in performance
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Background &
Motivation
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Coupling Thermal and Dielectric
Properties
A pyroelectric crystal
spontaneously changes
polarization when its
temperature is changed
The electrocaloric
effect is when a crystal
spontaneously changes
temperature when its
polarization changes
The pyroelectric effect allows us to
convert between thermal energy
and electrical energy
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Basic Operation of Engines and
Refrigerators
Refrigerator
Thermal
Reservoir
(Hot)
System
Thermal
Reservoir
(Cold)
Work
Environment
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Basic Operation of Engines and
Refrigerators
Engine
Thermal
Reservoir
(Hot)
System
Thermal
Reservoir
(Cold)
Work
Environment
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Engine & Refrigerator in Phase
Space
Refrigerator
Pressure
Pressure
Engine
Volume
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Volume
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Common Engineering Principles
• A material is used to transfer heat between
thermal reservoirs
• Complementary adiabatic processes facilitate the
thermodynamic cycle
Adiabatic Transformation
Equilibrate with hot
thermal reservoir
Equilibrate with cold
thermal reservoir
Adiabatic Transformation
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Example: Perovskite pyroelectric crystal:
ABO3
-ΔT
BaTiO3
-ΔT
-ΔT
Figure courtesy of Dr. Beckman
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Polarization
Electric work
Tlow
Thigh
Electric Field
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Why does this work?
The ordering of atomic scale dipoles causes a change in
the entropy
-ΔT
Field Direction
The change entropy requires a change in heat
DS =
ò
dq
T
In an adiabatic system, this causes a change in
temperature
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Pyroelectric vs. Thermoelectric
• Oscillating thermal
cycle
• Dipole orientation
• Applied electric field
• Exhibited by few
materials
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• Static thermal gradient
• Charge carrier motion
• No applied field
• Exhibited by all
materials
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What can we use to get a
larger change in entropy?
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Polymers
Liquid Crystals
Nanostructures
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Figure from
Longyi Bao
Nanotechnology
(2013)
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Polarization
Material Effect
Electric Field
Figure from Yyang340 Wikipedia
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Goals & Progress
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Functional Requirements
• Demonstrate the pyroelectric effect in liquid
crystals and polymers
• Convert waste heat to electrical work
• Measure properties of specimens
• Design a switching and harvesting circuit
• Expose pyroelectric device to a thermal cycle
• Withstand 400V across element
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Non-functional Requirements
• Well documented for future work
• Modular for varying pyroelectric materials
• Scalable to significant current and power levels
• Safety
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Deliverables
• Pyroelectric specimens
• Liquid crystal cells
• P(VDF-TrFE) films
• Characterization circuit
• Electrical property measurements
• Harvesting circuit
• Microcontroller code
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Risks
• High risk project utilizing new, unproven materials
and techniques
• Potentially transformative for thermal energy
harvesting industry
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Work breakdown
Trent Borman
John Etherington
-Group leader
-Project timeline
-Liquid crystal device fabrication
-Communication (weekly report)
-P(VDF-TrFE) device fabrication
-Control systems and control code
-Material electrical property curves
-Circuitry design
-Management of bill of materials
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Tommy Geske:
Joshua Grindeland
-Bibliography and Sourcing
-Web page design
-Liquid crystal device fabrication
-Circuitry design
-P(VDF-TrFE) device fabrication
-Pspice circuit design
-Thermodynamic curve generation
-Electrical device research
MAY14-25
System Block Diagram
Independent
Frequency Adjustment
ΔQ
Source/Load
Switching
Circuit
Contact
Pyroelectric Material
Produced Energy
Contact
Temp
Reading
Switching
Heat Transfer System
Control
(pyroelectric device housed
within)
VHigh
VLow
Microcontroller
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Design Stages
1
1. Pyroelectric specimens
2. Characterization circuit
3. Harvesting circuit
2
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3
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Polymer Specimens
•
•
•
•
P(VDF-TrFE)
Spin coating
1.2 micron thickness
ITO substrate
• Pinholing shorts ITO to top
electrode
• Process being refined
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Polymer Specimen Troubleshooting
•
•
•
•
Solvents
Atmospheric conditions
Contacts
Thickness
Currently in contact with a group which creates PVDF
films at Nebraska
Purchasing commercial polymer films to test concepts
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Barium Titanate Multi-layer
Capacitors
• Backup if high risk organic materials do not work
• Confirm functionality of harvesting circuit
• Well documented in literature
• Preliminary testing of BaTiO3 MLCs show high
breakdown resistance
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Liquid Crystal Specimens
• Commercial cells
• 5CB liquid crystal
• Increasing polarization
with electric field
• Frequency tuning
Instec Inc. Type SA and SB Liquid Crystal Cell
Structure of 5CB Liquid Crystal
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Liquid Crystal Specimens
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Liquid Crystal Troubleshooting
• Applying 210V results in breakdown preventing the
voltage from rising above 150V in the future
• 400V breakdown observed by other groups
• Solutions investigated
•
•
•
•
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New liquid crystals (hygroscopic)
Other liquid crystals (longer chain length)
External contacts (prevent conduction)
Increase temperature (phase change)
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Liquid Crystal Troubleshooting
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Characterization: Sawyer-Tower
8MΩ
V
0.1µF
22kΩ
V
The values of the resistors and capacitor will be modified to
match the various pyroelectric samples.
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Harvester: Switch-level Model
Increase Applied
Voltage
1
VLow
Cool &
Connect to
Voltage
VLow
Pyroelectric
Harvesting
Load
2
VHigh
Pyroelectric
Heat
Pyroelectric
3
4
Pyroelectric
Harvesting
Load
VHigh
Harvesting
Load
Pyroelectric
Beyond
Curie Temp
Harvesting
Load
Connect to Load
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Harvesting Circuit
PWR
100
USB
TMP
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Arduino UNO
ANALOG
A0
A1
A2
A3
A4
A5
POWER
RESET
3.3v
5v
GND
GND
VIN
DIGITAL (PWM~)
100
RESET
ICSP
AREF
GND
13
12
~11
~10
~9
8
7
~6
~5
4
~3
2
Tx> 1
Rx< 0
1k
100µ
Vs
Vcontrol
+
v
-
Device
Temp
330k
Offset
Null
RL
100k
10k
+
-
47k
10k
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5M
Vs
1µ
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Results
Device Characteristics
Voltage
Current
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Future Work - Concept Sketch
The device consists of three
subsystems:
Mechanical/Heat Transfer – Piston,
stepper motor, silicone oil, heat sink,
heating band.
Material – Pyroelectric material and
contacts.
Electrical – Thermocouples,
harvesting circuit, switching circuit,
and motor controller.
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Conclusion
• Electrical characterization has preliminary results,
but is an ongoing project
• Preliminary circuits designed
• Heat transfer system will be explored later
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Acknowledgements
• We would like to thank Scott Beckman and Sumit
Chaudry for their role as our advisors
• We would like to thank our client Pete Onsted for
his generous donation to foster collaboration
between materials science and electrical
engineering
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Additional Information
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Safety
• High voltages
• Lockout tag out
• Insulating gloves
• Temperatures
• Heat resistant gloves
• Oil resistant clothing
• Safety goggles
• Chemicals
•
•
•
•
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Chemical resistant gloves
Storage and disposal plan
Fume hood
Safety goggles
MAY14-25
Cost Analysis – Liquid Crystals
Supplier
Name
4’-PentylSigma Aldrich 4biphenylcarbonitrile
4’-HexylSigma Aldrich 4biphenylcarbonitrile
4’-OctylSigma Aldrich 4biphenylcarbonitrile
Homeotropic
Instec Inc.
alignment LC cells
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Unit Quantity
Price
Subtotal
Gram
1
$ 72.30 $ 72.30
Gram
1
$ 90.20 $ 90.20
Gram
1
$ 84.80 $ 84.80
Holders
20
$ 14.00 $ 280.00
Total $ 527.30
MAY14-25
Cost Analysis – Polymer
Supplier
Name
Delta
ITO coated glass
Technologies slides
Piezotech
PVDF-TrFE 70/30
N,NSigma Aldrich Dimethylformamide
1oz/30mL
Fisher
Polypropylene
Scientific
Bottles
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Unit
Quantity Price
Subtotal
Piece
Gram
20
2
$ 8.00 $ 160.00
$ 10.00 $ 20.00
Liter
1
$ 85.40 $ 85.40
12ct Pack
2
$ 12.53 $ 25.06
Total $ 290.46
MAY14-25
Cost Analysis – Lab Supplies
Supplier
Fisher
Scientific
Fisher
Scientific
Fisher
Scientific
Fisher
Scientific
Name
Unit
Acetone (Certified
ACS)
4L Bottle
Methanol (Certified
ACS)
4L Bottle
Best Butyl II Gloves Pair
4.4 x 8.4 Lint Free
Wipers
280ct Box
Cotton-Tipped
Fisher
Wooden
Scientific Applicators
1000ct Pack
Fisher
Graduated
Scientific Disposable Pipettes 500ct Box
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Quantity
Price
Subtotal
1
$ 22.06 $ 22.06
1
$ 16.12 $ 16.12
1
$ 50.47 $ 50.47
2
$ 3.82 $
7.64
1
$ 7.71 $
7.71
1
$ 14.29 $ 14.29
MAY14-25
Cost Analysis – Lab Supplies
Supplier
Chem
Stores
Ted Pella
Inc.
Ted Pella
Inc.
Ted Pella
Inc.
Ted Pella
Inc.
Ted Pella
Inc.
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Name
Unit
Disposable Nitrile
Gloves 50pr/box Box
Carbon Conductive
Sheet
Pack/10
Copper Conductive
Tape
Roll
Double Sided
Kapton Tape
Roll
PELCO Water Based
Carbon Paint
50g Bottle
PELCO Colloidal
Silver Paste
25g Bottle
Quantity
Price
Subtotal
2
$ 6.04 $ 12.08
1
$ 39.75 $ 39.75
1
$ 41.25 $ 41.25
1
$ 52.10 $ 52.10
1
$ 9.95 $
1
$ 59.50 $ 59.50
TOTAL $ 332.92
9.95
MAY14-25
Cost Analysis - Electrical
Supplier
Name
Unit
Quantity Price
Sparkfun
Arduino Uno
Board
1
Digkey
35V - 1uF - MLC - X7R Capacitor 5
$
Digikey
DC/DC 1kV converter Unit
1
$ 189.02 $ 189.02
Digikey
Transistor Optocoupler 6-DIP
10
$
Digikey
3 Row solderless BB
Board
1
$ 122.04 $ 122.04
Digikey
Unit
3
$
Digikey
Temperature Sensor
K-type Temperature
Probe
Unit
3
$ 14.95 $ 44.85
Digikey
K-type Thermocouple
female sockets
Unit
3
$
7.10
$ 21.30
Digikey
AC/DC wall pack
1
$
4.68
$
Unit
$ 29.95 $ 29.95
0.23
0.94
1.42
TOTAL
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Total
$
$
$
1.13
9.40
4.26
4.68
$ 426.63
MAY14-25
Adiabatic Electrocaloric Effect
-1 E2 ¶P
DT =
T dE
ò
Cv E1 ¶T
Pyroelectric Coefficient
¶P
p=
¶T
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Manual Heat Transfer System
• Manual rotation between cold and hot plates.
Figure from Olsen Journal of Energy (1982)
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Regenerative Heat Transfer System
Utilize a series of materials with a gradient of
transition temperatures to maximize efficiency
Figure from Olsen Journal of Energy (1982)
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Automated Heat Transfer System
Figure from Olsen, Bruno, Briscoe, Dullea
Ferroelectrics (1984)
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Polymer Spin Coating
• 3-4 drops of solution.
• 5 wt% at 750-1250 rpm for
30-45s.
• 10 wt% at 2000-3000 rpm for
30s, and 750 rpm for 60s.
• 10 wt% at 3000 rpm for 30s
has uniform 1.2 micron
thickness.
• Annealed for 30m at 80°C
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Preliminary Polymer Characterization
P(VDF-TrFE) Polarization - Electric Field
1.8
1.6
Polarization (μC/cm2)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
100
200
300
Electric Field (kV/cm)
250 kV/cm
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400
500
600
150 kV/cm
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Polymer Micrographs
• Presence of pinholes and photoresist.
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Liquid Crystal Material
• Nematic liquid crystals were chosen due to their
significant entropy change.
• 4'-Pentyl-4-biphenylcarbonitrile (5CB) was chosen
due to literature on electrocaloric effect.
• 4’-Hexyl-4biphenylcarbonitrile, and
4’-Octyl-4biphenylcarbonitrile were also purchased
for their higher transition temperature.
Structure of 5CB Liquid Crystal
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Preliminary Liquid Crystal
Characterization
22.5
20
17.5
15
Polarization (μC/cm2)
• Shows increasing
polarization with
increasing field as
expected.
• Max polarization
should occur at max
field.
5CB Polarization vs Electric Field
12.5
10
7.5
5
2.5
0
-2.5
-600
-400
200 kV/cm
500 kV/cm
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-200
0
200
400
Electric Field (kV/cm)
300 kV/cm
600
800
400 kV/cm
600 kV/cm
MAY14-25
Ceramic Nanosheets
• Liquid crystal holders
• Preliminary characterization in
progress
Nakato et al.
Journal of Physical
Chemistry C (2011)
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Microcontroller
Isolator Trigger &
Stepper Control
• Arduino Uno
• Meets our specification
• Low cost
• Large user community,
base code
• Compatible with our
stepper motor and
driver
Thermocouples
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Thermocouple Testing
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