P. R. POTE (PATIL) COLLAGE OF ENGINEERING & MANAGEMENT, AMRAVATI.

ENERGY HARVESTING THROUGH REVERSE ELECTROWETTING

SEMINAR ON

byVAIBHAV.B.VAIDYA

FINAL YEARELECTRICAL ENGINEERING DEPARTMENT

GUIDE

Prof. T.A.MOHAMMADASSISTANT PROFESSOR

ELECTRICAL ENGINEERING DEPARTMENT

HEAD

Prof. S.B.WARKDHEAD OF DEPARTMENT

ELECTRICAL ENGINEERING DEPARTMENT

1. What is energy harvesting ?

2. What is electrowetting ?

3. Surface energy

4. Contact angle

5. Reverse electrowetting

6. How it works ?

7. Arrangements of REWOD

8. How to make it efficient ? & challenges

9. Interesting application

10. References

Contents

WHAT IS ENERGY HARVESTING ?

Energy Harvesting is a simple phenomenon that deals withthe conversion Of the freely available environmental energyinto the electrical power

Methods of Energy Harvesting:• Reverse Electrowetting• Piezoelectric • Electrostatic • Electromagnetic

WHAT IS ELECTROWETTING?

• Electrowetting is a microfluidic phenomenon that changes the surface tension of the liquid on the solid surface on application of voltage.

• ELECTROWETTING ON DIELECTRIC(EWOD) – Liquid spreading on the dielectric surface is facilitate by

electrically induced increase in the dielectric surface wettability.

Motion of a conductive liquid on a dielectric-coated conductive substrate.

Wettability change arises from the extra electrostatic energy that is associated with electrically charged liquid-solid interface.

SURFACE ENERGY• Surface energy may be defined as the excess energy at the

surface of the material compared to the bulk.

CONTACT ANGLE• The contact angle is the angle measured through the liquid, where

a liquid/vapor interface meets a solid surface.

REVERSE ELECTROWETTING• Converting mechanical energy of liquid motion into electrical

current, thus achieving reverse electrowetting (REWOD).

• Constant bias voltage between droplet and electrode.• External mechanical actuation - moves the droplet to force the

decrease of its overlap with the di-electric film coated electrode.

• Converts pressure energy into electrical energy.

• Liquid metal alloy- Galinstan.

• Instep Nano power- research.

HOW IT WORKS?• Cmax----->Cmin because of change in effective contact area.

ARRANGEMENTS OF REWOD

HOW TO MAKE IT EFFICIENT?• More energy is generated when the conductivity of the fluid is

more.

• Electrode material of low conductivity is preferable.

• Using more droplets thereby increasing the effective contact area.

• Making the channel length more.

CHALLENGES• Energy produced is very less.

• Device manufacturing for practical purposes.

INTERESTING APPLICATION• When we walk our body produces 40 watts of mechanical power as

heat when our feet strike the ground. • A special electricity-generating cushion placed inside the soles of a

regular pair of shoes can transform some of that footfall power into several watts of electricity.

• Over the course of a single day, the generated energy, which gets stored in a small battery in the sole, provides enough electricity for a pedestrian to extend her smartphone’s battery life.

CONCLUSION• As a fact only 11% of renewable energy

contributes to our primary energy. If this project is deployed then not only we can overcome the energy crises problem but this also contributes to create a healthy global environmental change.

• The researchers are working for large amount of power generation by using reverse electrowetting. Since the energy generated by this technic is not much to come in commercial power stations but we can view this method as secondary source of power for light load.

REFERENCES 1) Tom Krupenkin & J. Ashley Taylor, Reverse electrowetting as a

new approach to high-power energy harvesting. Nature Communications, 2011, pp. 1-4.

2) Fusayo Saeki, Jean Baum, Hyejin Moon, Jeong-Yeol Yoon, Chang-Jin “CJ” Kim and Robin L. Garrell Electrowetting on Dielectrics (EWOD): Reducing Voltage Requirements for Microfluidics. University of California, Los Angeles, 2012.

3) Michael George Pollack Electrowetting-Based Microactuation of Droplets for Digital Microfluidics. Department of Electrical and Computer Engineering Duke University, 2001, pp. 7-14.

4) Gordon F. Christopher and Shelly L. Anna. Microfluidic methods for generating continuous droplet streams. Journal of Physics D: Applied Physics, 2007, pp. 319–336.

THANK YOU