1. Energy Harvesting Technology and Applications
Team 2
AFRL WSN Health Diagnostic
Energy Harvesting Technology and Applications

2. Introduction What is energy harvesting? Why use energy harvesting?
The process by which energy is derived from external sources
Why use energy harvesting?
Renewable source
Allows for remote charging in applications

3. Energy Harvesting Background
Energy harvesters provide a very small amount of power for low-energy electronics
The energy source for energy harvesters is present as ambient background and is free
As opposed to large-scale energy generation which costs money

4. Why Use Energy Harvesting Technology?
Converted energy can be stored in a capacitor for short-term use or a battery for long-term use.
Allows for the battery (or a charger) to be taken out of the equation of an application since it sources energy from the environment

5. Ways to Harvest Energy Materials Other Piezoelectric Pyroelectric
Photovolatics
Other
Kinetic Energy
RF Energy

6. Piezoelectric Effect (Pressure)
Converts mechanical strain to electric current
Produces power on the order of mW
Useful for small applications
Handheld devices
Light bulbs
Human Motion
Acoustic Noise
Vibrations
Pressure

7. Pyroelectric Effect
Converts changes in temperatures to electric current
Stable for temperatures above 1200 ⁰C
High thermodynamic efficiency
Used in
Power Plants
Automobiles
Pyroelectricity (from the Greek pyr, fire, and electricity) is the ability of certain materials to generate a temporaryvoltage when they are heated or cooled.[1] The change in temperature modifies the positions of the atoms slightly within the crystal structure, such that the polarization of the material changes

8. Other Kinetic Energy
Converts human and/or natural motion into electric current
Found in
Wind Turbines
Ocean Wave Buoys
Human Motion

9. Photovoltaic Effect Also known as solar power
Converts solar radiation into DC
Found just about everywhere and gaining more popularity

10. RF Energy Harvesting Converts RF signal energy into DC power
RF energy is available in a wide array of frequency bands due to everyday technologies
Cell Phones
Radio Towers
WiFi Routers
Laptops
TV Signals
Only a tiny amount of power can be harvested, good for low power applications (Ex: A WiFi router can transmit mW)
Usually very short distance, however Powercast demonstrated energy harvesting at 1.5 miles

11. Energy Harvesting and Wireless Sensor Networks
Our project uses RF power harvesting technologies

12. Why RF Energy Harvesting?
Ultra-low power, battery free applications
Perfect for wireless sensor networks

13. RF Power Sources Intentional Sources Anticipated Ambient Sources
Powercast utilizes a direct RF energy source, dedicated to providing RF energy for harvesting
Anticipated Ambient Sources
Routers, cell phone transmitters
Unknown Ambient Sources
Microwave radio links, mobile radios

14. A Closer Look at a Powercast Sensor Node
Module Components & Features
Powercast P2110 Powerharvester™ Receiver
MCU: Microchip PIC24 XLP
Radio module
Microchip MRF24 ( )
RF Powerharvester
System power: 3.3V
Capacitor
50mF (as low as 3300uF)
Discrete sensors: Temp, Humidity, Light
Wireless protocol: MiWi™ P2P

15. Sensor Module System Voltage

16. Powercaster Transmitter
Center Frequency = 915MHz
Intentional RF Source
Directional Antenna

17. Complete RF Energy Transmission

18. P2110 Powerharvester Receiver Efficiency

19. Packet Frequency vs. Distance from RF Source

20. Powercast Sensor Performance Overview
Optimized RF Powerharvesting for the transmitter frequency
RF Powerharvesting allows for remote placement of sensor nodes
Great performance due to a design that focuses on minimizing power consumption in each node
Proprietary wireless protocol

21. Conclusion
Power harvesting technologies are everywhere and efficiencies are vastly improving
Simply look at solar efficiencies
Most of the world’s energy in the future will be generated using power harvesting technologies