Wilburt Geng, Jonathan Mountford, Leah Schrauben Energy Harvesting Wilburt Geng, Jonathan Mountford, Leah Schrauben

Agenda What is energy harvesting? Classes of energy harvesting systems Anatomy of an energy harvesting system Common mechanisms and applications Kinetic/inertial Piezoelectric Solar Thermal Summary Questions http://www.silabs.com/Support%20Documents/TechnicalDocs/implementing-energy-harvesting-in-embedded-system-designs.pdf

What is it, and why do we care? Free energy! PICTURES: http://ecx.images-amazon.com/images/I/511aMrtVbWL._SY300_.jpg https://www.westsussex.gov.uk/media/4178/halnaker_windmill.jpg?anchor=center&mode=crop&width=1500&height=900&rnd=130679684350000000 https://static.dezeen.com/uploads/2011/02/dzn_Sol-by-Shin-Azumi-at-Dezeen-Watch-Store-1.jpg http://assets.inhabitat.com/wp-content/blogs.dir/1/files/2010/04/shoe.jpg http://www.digikey.com/-/media/Images/Article%20Library/TechZone%20Articles/2014/December/Evaluating%20energy-harvesting%20technologies%20for%20wearable%20designs/article-2014december-evaulating-energy-harvesting-fig2.jpg?la=en&h=289&w=500&ts=51a9c293-4e10-4715-a93b-d7a8bab8bb5b

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 http://www.silabs.com/Support%20Documents/TechnicalDocs/implementing-energy-harvesting-in-embedded-system-designs.pdf

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

Perpetually Powered Sensor Ambient Energy: Motion, light, heat Energy Harvester Energy Storage & Power Mgmt Environment: Temperature, position, status Sensor(s) Ultra Low Power Microcontroller Low Power Transceiver http://www.silabs.com/Support%20Documents/TechnicalDocs/implementing-energy-harvesting-in-embedded-system-designs.pdf Adapted from: http://focus.ti.com/graphics/mcu/ulp/energy_harvesting_embedded_systems_using_msp430.pdf

Energy Harvesting Mechanisms Kinetic/Inertial Piezoelectric Solar Thermal

Energy Harvesting Mechanisms Kinetic/Inertial Piezoelectric Solar Thermal http://cdn.intechopen.com/pdfs-wm/45931.pdf

Powering watches using natural motion 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

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

Energy Harvesting Mechanisms Kinetic/Inertial Piezoelectric Solar Thermal http://dev.nsta.org/evwebs/2014102/images/piezoelectric_effect.jpg

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 https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/12072/12072.pdf

Energy Harvesting Mechanisms Kinetic/Inertial Piezoelectric Solar Thermal https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQ0MyONnfsRKJCl-VfW-DHX6sNxBx-qgeV__uMTDKixXqoCLPHawaCI7fbH

Measuring and displaying travel speeds of cars 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 http://www.radarsign.com/wp-content/uploads/2012/06/Radarsign-TC-1000-Radar-Speed-Sign-Spec-Sheet-16v1.pdf

Energy Harvesting Mechanisms Kinetic/Inertial Piezoelectric Solar Thermal http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig3.jpg

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/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig4.jpg

Summary Free, reusable energy Classes of harvesting systems: Main energy harvesting mechanisms: Kinetic Piezoelectric Solar Thermal Classes of harvesting systems: Pulse Continuous Primarily used to power wireless sensors Supplies low power, low efficiency, and low maintenance solutions

Resources General: Solar: Piezoelectric Kinetic: Thermal: 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 Solar: https://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/photovoltaics-report-slides.pdf http://science.howstuffworks.com/environmental/energy/solar-cell1.htm Piezoelectric http://www.explainthatstuff.com/piezoelectricity.html http://www.piceramic.com/applications/piezo-energy-harvesting.html Kinetic: 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 Thermal: 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

Questions?

appendix

Traditional Energy Generation Transformation of chemical to electrical energy Amount of fuel needed to generate 1 kWh of energy Coal = 1.04 lbs Natural gas = 0.01 Mcf Petroleum = 0.07 gallons Cheap, efficient, but requires connection to power grid https://www.eia.gov/tools/faqs/faq.cfm?id=667&t=3

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

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 Solar Panel - https://www.adafruit.com/products/200

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

Kinetic: Watch http://www.seiko-cleanenergy.com/images/img_kinetic07.gif

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 http://www.bloomberg.com/news/articles/2012-04-23/charge-your-phone-just-by-walking 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

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://www.piceramic.com/applications/piezo-energy-harvesting.html http://dev.nsta.org/evwebs/2014102/images/piezoelectric_effect.jpg

Solar Applications in space exploration and general power generation Efficiencies between 15-20% for most solar panels Doped silicon material converts solar to electrical power http://ecofriend.com/wp-content/uploads/2012/07/icharge-eco_Znii5_69.jpg http://www.radarsign.com/wp-content/gallery/neighborhood-applications/radarsign-solar-powered-driver-feedback-sign-concord-oh.jpg https://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/photovoltaics-report-slides.pdf http://science.howstuffworks.com/environmental/energy/solar-cell1.htm

Solar: In Depth Mechanism https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQ0MyONnfsRKJCl-VfW-DHX6sNxBx-qgeV__uMTDKixXqoCLPHawaCI7fbH

Thermal Voltage output is proportional to temperature difference 5-8% efficiency Thermal circuit: Current = heat flow Voltage = temperature Heat Source: Hot surfaces such as pipes, exhaust gas, direct sunlight, or human body Heat Sink: Typically convection to the air http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig1.jpg http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig1.jpg

Thermal: Why is it useful? Usually produces < 1V Boost converters bump voltage up Supplies power to ultra-low power wireless sensors Very little maintenance Extremely reliable http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig4.jpg http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63655/63655-fig4.jpg