Transcript pptx

Energy Harvesting
Wilburt Geng, Jonathan Mountford,
Leah Schrauben
Agenda
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What is energy harvesting?
Classes of energy harvesting systems
Anatomy of an energy harvesting system
Common mechanisms and applications
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Kinetic/inertial
Piezoelectric
Solar
Thermal
• Summary
• Questions
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What is it, and why do we care?
Free energy!
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What is it, and why do we care?
• Small amounts of energy from ambient sources
• Power devices without connection to power grid
• Low power, low energy, low maintenance
• Little to no environmental footprint
• Ideally allow for ‘perpetual operation’ embedded systems
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Classes of Energy Harvesting Systems
Continuous
⇁ Low leakage, high capacity power
container
⇁ Transitions between low power
sleep and high power usage states
⇁ Always powered, always harvesting
Pulse
⇁ Unpowered until burst of energy is
received and stored
⇁ Powers on and performs simple
task using energy burst
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Perpetually Powered Sensor
Ambient Energy:
Motion, light,
heat
Environment:
Temperature,
position, status
Energy
Harvester
Energy
Storage &
Power Mgmt
Sensor(s)
Ultra Low
Power
Microcontroller
Low Power
Transceiver
Adapted from: http://focus.ti.com/graphics/mcu/ulp/energy_harvesting_embedded_systems_using_msp430.pdf
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Energy Harvesting Mechanisms
• Kinetic/Inertial
• Piezoelectric
• Solar
• Thermal
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Energy Harvesting Mechanisms
• Kinetic/Inertial
• Piezoelectric
• Solar
• Thermal
http://cdn.intechopen.com/pdfs-wm/45931.pdf
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Application: Kinetic
Powering watches using natural
motion
• Utilizes natural motion of arm
• Normal batteries need to be
replaced regularly
• Allows for more accurate quartz
timing, without the need of
replacement batteries
• Doesn’t need to be rewound like a
traditional watch
http://www.seiko-cleanenergy.com/images/img_kinetic07.gif
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Application: Kinetic
Inertia Energy Harvester
• General concept to convert natural
oscillations to electrical energy
• Most applicable to wearable
technology
http://cdn.intechopen.com/pdfs-wm/45931.pdf
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Energy Harvesting Mechanisms
• Kinetic/Inertial
• Piezoelectric
• Solar
• Thermal
http://dev.nsta.org/evwebs/2014102/images/piezoelectric_effect.jpg
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Applications: Piezoelectric
Monitoring pavement year-round
deterioration
• Concept proposed by Federal
Highway Administration
• Too many roads to easily
monitor manually
• Surface wear not indicative of
internal wear
• Higher upfront cost
https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/12072/12072.pdf
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Energy Harvesting Mechanisms
• Kinetic/Inertial
• Piezoelectric
• Solar
• Thermal
https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQ0MyONnfsRKJCl-VfW-DHX6sNxBx-qgeV__uMTDKixXqoCLPHawaCI7fbH
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Applications: Solar
Measuring and displaying travel
speeds of cars
• Allows autonomous
monitoring of car speeds
• Operation without
difficult/tedious connections to
power grid
• Internal batteries allow for
nearly continuous operation
https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/12072/12072.pdf
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Energy Harvesting Mechanisms
• Kinetic/Inertial
• Piezoelectric
• Solar
• Thermal
http://electronicdesign.com/sitefiles/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig3.jpg
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Applications: Thermal
Monitoring bearing health in
airplane turbine engines
• Running wires is expensive
• Hard to reach places for
humans
• Limited space
• Low maintenance
http://electronicdesign.com/sitefiles/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig4.jpg
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Summary
• Free, reusable energy
• Main energy harvesting
mechanisms:
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Kinetic
Piezoelectric
Solar
Thermal
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Classes of harvesting systems:
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Pulse
Continuous
Primarily used to power wireless
sensors
Supplies low power, low
efficiency, and low maintenance
solutions
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Resources
General:
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https://www.eia.gov/tools/faqs/faq.cfm?id=667&t=3
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4494336
http://www.silabs.com/Support%20Documents/TechnicalDocs/implementing-energy-harvesting-in-embedded-system-designs.pdf
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https://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/photovoltaics-report-slides.pdf
http://science.howstuffworks.com/environmental/energy/solar-cell1.htm
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http://www.explainthatstuff.com/piezoelectricity.html
http://www.piceramic.com/applications/piezo-energy-harvesting.html
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http://www.seiko-cleanenergy.com/images/img_kinetic07.gif
http://cdn.intechopen.com/pdfs-wm/45931.pdf
http://www.extremetech.com/extreme/161079-kinetic-energy-harvesting-everyday-human-activity-could-power-the-internet-of-things
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http://www.mouser.com/thermal_energy_harvesting/
http://www.digikey.com/en/articles/techzone/2011/oct/thermoelectric-energy-harvesting
http://electronicdesign.com/energy/use-thermal-energy-harvesting-supply-your-sensor-s-power
Solar:
Piezoelectric
Kinetic:
Thermal:
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Questions?
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appendix
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Traditional Energy Generation
• Transformation of chemical to electrical energy
• Amount of fuel needed to generate 1 kWh of energy
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Coal = 1.04 lbs
Natural gas = 0.01 Mcf
Petroleum = 0.07 gallons
• Cheap, efficient, but requires connection to power grid
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Why we are interested
• Ambient background energy usable energy
• Easy energy for low power devices
• Indefinite functionality without attachment to power grid or reliance on
batteries
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4494336&tag=1
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Application
• 6V 2W Solar Panel - $29 - Medium Solar Panel
• 4V 10µW Solar Panel - $1.95 - CPC1822
• 9VOC 4W Optimal TEG - $23.73 - TG12-4-01LS
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Kinetic
• Capture mechanical motion and
converts it to electrical energy
• Most applicable to wearable
technology
• Due to low power production, usually
used in minimal power operations or
to extend battery power
http://www.seiko-cleanenergy.com/images/img_kinetic07.gif
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Kinetic: Watch
http://www.seiko-cleanenergy.com/images/img_kinetic07.gif
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Kinetic: Basic Concept
• A magnet is attached to a spring
• Walking and other motions cause the magnet
to bounce through a coil solenoid
• The motion produces small amounts of
current
http://cdn.intechopen.com/pdfs-wm/45931.pdf
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Piezoelectric
• Mechanical deformation of piezo crystal via tension or pressure
generates electric charge imbalance
• Applications in structural health/maintenance, product monitoring during
transport, etc.
http://dev.nsta.org/evwebs/2014102/images/piezoelectric_effect.jpg
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Solar
• Applications in space
exploration and general
power generation
• Efficiencies between 1520% for most solar
panels
• Doped silicon material
converts solar to
electrical power
http://ecofriend.com/wpcontent/uploads/2012/07/ichargeeco_Znii5_69.jpg
http://www.radarsign.com/wpcontent/gallery/neighborhoodapplications/radarsign-solar-powered-driverfeedback-sign-concord-oh.jpg
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Solar: In Depth Mechanism
https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQ0MyONnfsRKJCl-VfW-DHX6sNxBx-qgeV__uMTDKixXqoCLPHawaCI7fbH
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Thermal
• Voltage output is proportional to
temperature difference
• 5-8% efficiency
• Thermal circuit:
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Current = heat flow
Voltage = temperature
• Heat Source:
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Hot surfaces such as pipes, exhaust
gas, direct sunlight, or human body
• Heat Sink:
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Typically convection to the air
http://electronicdesign.com/sitefiles/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig1.jpg
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Thermal: Why is it useful?
• Usually produces < 1V
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Boost converters bump voltage up
• Supplies power to ultra-low
power wireless sensors
• Very little maintenance
• Extremely reliable
http://electronicdesign.com/sitefiles/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig4.jpg
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