A New renewable Energy Generating Power from EPAM (Electroactive Polymer Artificial Muscle)

1. A New renewable EnergyGenerating Power from EPAM (Electroactive Polymer Artificial Muscle) Professor Kesheng Wang Department of Production and Quality EngineeringNorwegian University of Science and TechnologyN-7491 Trondheim, Norway Tel. 47 73 59 7119, Fax 47 73 59 7117E-mail: kesheng.wang@ipk.ntnu.no KDL, IPK NTNU

2. ACTUATOR W E EAP ENERGY (ELECTRICAL) MECHANICAL WORK GENERATOR OR SENSOR A New renewable Energy Generating Power from EPAM (Electroactive Polymer Artificial Muscle) KDL, IPK NTNU

3. Traditional Renewable Energy • Photovoltaic power generation • Wind power generation • Wave power generation • Biomass power generation KDL, IPK NTNU

4. Problems for Traditional Renewable Energy Generation • Complex mechanical devices • Big place to install devices • Difficult maintenance • High cost • Long time to make them be main energy production • …… KDL, IPK NTNU

5. New Renewable Energy • A new power generation method • Ecological and practical energy • EPAM method • Generating energy by the movement of any objects • Large-scale power generation (wind, Wave) • Small-scale power generation (human movement) KDL, IPK NTNU

6. ACTUATOR EAP W E MECHANICAL WORK ENERGY (ELECTRICAL) GENERATOR OR SENSOR What is an Electroactive Polymer Artificial Muscle? • EAP converts electrical energy to mechanical work and vice versa. KDL, IPK NTNU

7. Electrostrictive Polymer Many Types of EPAMs Dielectric elastomers are particularly promising Dielectric Elastomer a.k.a. Electroelastomers Conducting Polymers IPMC “Artificial Muscle” Thermal and Others Gels Nanotubes KDL, IPK NTNU

8. Advantages of EPAM • Lighter – low density, high performance, multifunctional polymers (Polymers are 1/8 the density of common materials used in engines and generators) • Cheaper – inexpensive materials, fewer parts, no precision machining • Quieter – high energy density and compliance of polymers allows quiet primarily sub-acoustic operation with few moving parts • Softer – rubbery materials are impedance matched to large motions (e.g. human motion, engines) • Versatile – polymers are scale-invariant; systems can be made in variety of form factors (conformal, elongated, etc.) KDL, IPK NTNU

9. Compliant Electrodes (2) +Vin (low) +Vout (high) + + + + + _ _ _ _ _ Dielectric Elastomer +Vin (low) +Vout (high) + + + + + _ _ _ _ _ Dielectric Elastomers: Principle of Operation Polymer film Voltage off Compliant electrodes (on top and bottom surfaces) • Dielectric elastomers are a type of EAP that uses an electric field across a rubbery dielectric with compliant electrodes • Variable capacitor generator– energy generated as nearly incompressible polymer layers increase in area and decrease in thickness when stretched V Voltage on BASIC FUNCTIONAL ELEMENT EAP STRETCHED Energy = ½ Qo2 (1/Cf - 1/Ci) C = ereox film area/film thickness KDL, IPK NTNU EAP RELAXED

10. V V DIAPHRAGM TUBE EXTENDER Active Electrode Area V V V1 BIMORPH STACK V2 V V UNIMORPH ROLL Many Possible EAP Transducer Configurations KDL, IPK NTNU

11. .45 Latest Acrylic Energy Density Tests .40 .35 .30 Specific Energy Density [J/g] .25 .20 .15 .10 End of 1999 Acrylic Tests Verification of Phenomena .05 Initial Acrylic Tests HS3 Silicone 2186 Silicone 0 Time 12/98 6/99 12/99 Demonstrated Specific Energy Density Polymer Dielectric Elastomer Materials • Several elastomers work well • Acrylic and silicone are most promising and have shown exceptional energy density • Acrylic has greater energy density but also greater damping and electrical leakage • Silicone has exceptional temperature range (–60 to 260 C) KDL, IPK NTNU

12. Voltage Step-Up Voltage Step-Down Output Polymer Device Battery Power Conversion and Management • Power available from dielectric elastomer EAPs is at a high voltage (e.g., 2 kV) • For most applications we would like to charge batteries at a low voltage (3–48 volts) • Some applications can use high voltage directly (e.g. night vision optics, in-boot actuators) • High-voltage is not all bad: low current can allow for thinner, lighter wires and simpler connectors • Battery or capacitor energy storage is needed to smooth output KDL, IPK NTNU

13. Multifunctionality ACTUATOR or GENERATOR SENSOR Dielectric elastomers can combine several functions STRUCTURE: Support, Transmission, Spring, Damper • Simpler • Lighter • Higher Performance KDL, IPK NTNU

14. Artificial Muscle: Dielectric Elastomer Actuation Artificial Muscle Roll Dielectric elastomers have already shown unique capabilities in a variety of actuator applications Bending Rolls Mirror Shape Control Insect-inspired Robot Snake Robot Segment KDL, IPK NTNU

15. Engine Generators Applications of EPAM Many power generation applications can benefit from the advantages of EAPs Shoe and other Human-Powered Generators Parasitic Energy Harvesting Wave & Tidal Power Pumps and valves for fuel management Wind Power KDL, IPK NTNU

16. Harvesting Human Movement Several possibilities that do not excessively burden the wearer: Heel Strike and Shoe Flexure 2–20w Backpack Suspension and Padding 0.5–5w Limb Swing 0.2–3w Chest or Torso Expansion From Breathing or Routine Movement 0.1–1w Hand or Leg Cranked Generator for Emergency Back-up (Short-term) 10–100w KDL, IPK NTNU

17. Enabling a Heel-strike Generator • Energy from the heel strike is “free” - it would otherwise be dissipated as heat • Energy converted per step with reasonable heel compression can be up to 5 J • Power generated (both feet) during walking is 1W to 10 W • The amount of electrostrictive polymers needed to convert 5 J is less than 50 g or 50 cc. • Electromagnetic or piezoelectric devices would weigh more than 10 times this weight Conventional technology (“direct drive”; including piezoelectrics) EAP-based design Relative Mass, Size, or Cost for boots with equivalent performance and functionality KDL, IPK NTNU

18. + Dielectric Elastomer (EAP) + + _ _ _ +Vout + _ + _ +Vin Base Compliant Electrodes (2) EXPANDED + + + +Vout +Vin _ _ + _ + _ _ CONTRACTED Heel-strike Generator • Developed a heel-strike generator to capture free energy while walking • Demonstrated up to 0.8 J per heel strike • Developed multi-layer polymer fabrication techniques • Demonstrated 15 layer device Heel-Strike generators are expected to produce 1W of power under normal walking conditions KDL, IPK NTNU

19. Applications of a Heel-strike Generator • Boot generator can assist the dismounted soldier in several distinct ways • Power source or battery recharger to reduce battery weight for a mission • Smart Shoes, Multifunctional Footwear - simplify logistics by reducing the number of separate batteries or devices required • power an instrument that should logically be located in a boot for best operation: • personal navigation system, medical status monitor, foot warmer • power a device that could be located in a boot for weight or space savings • Friendly ID beacon, comm link, magnetometer, chem/bio detector, special battery or capacitor for high-voltage device such as night vision scope • Dynamic Footwear - Actuation or Adaptability for enhanced performance • reduced injury • improved comfort • more efficient load carrying OFW Concept Source: Natick KDL, IPK NTNU

20. MAVs, Land Robots & Vehicles need efficient and quiet Electrical + Mechanical Power Future Soldier Systems need efficient and quiet Electrical + Mechanical Power Can EPAMs overcome limitations of Small Portable Power Sources? • Current small fuel-burning engines/generators: • Noisy • Inefficient (typically 5-7%) • Require special fuel mixtures • Not inherently hybrids or multifunctional - Need separate components for both mechanical and electrical energy production • Batteries: • Electric only • Low energy density (heavy) • Slow to recharge, hard to dispose • Fuel cells: • Electric only • Limited to certain types of fuel and cannot run on dirty fuel • Require additional components and warm-up time KDL, IPK NTNU

21. Engine is Too Noisy! Specific Example: Mentor Micro Air Vehicle • DARPA TTO project for a MAV capable of operation in cluttered environments Vehicle Specifications: Total Weight (Wet):550 g Engine 140 g Fuel & Tank 75g Batteries for electronics 30g and servos Power required (hover): 98 W Performance: Hover Duration 8 min. (50g fuel) Payload Capacity: 30 to 70g Superfly 2.5 “World’s First Hovering Ornithopter” University of Toronto Institute for Aerospace Studies with SRI KDL, IPK NTNU

22. Palm-Power Program • Specific Needs can be seen in Palm Power Program Goals: • Convert chemical energy of common fuels to mechanical / electrical energy for needs • 20 Watt average power level at 12 Volts DC • Typical Missions : • Three-hour MAV reconnaissance mission - 1000 Wh/kg • Three-day Land Warrior mission - 2000 Wh/kg • Ten-day special operations reconnaissance mission - 3000 Wh/kg KDL, IPK NTNU

23. Electromagnetic Generator Crankshaft Conditioning Piston Electronics Electrical Output Cylinder Cylinder Conventional Generator System An All-polymer Engine: The Answer? • Light: Uses lightweight electroactive polymers instead of metallic piston/cylinders + electromagnetic generator • Can operate sub-acoustically or with quieter external combustion cycles • Unlike fuel cells and many small engines, can run efficiently on dirty logistics fuels • Low cost and rugged – eliminates parts and bearings • Can be made in a wide variety of shapes and sizes Dielectric elastomer Conditioning Electronics Electrical Output Comparable Polymer Engine System KDL, IPK NTNU

24. 1 P 4 2 3 V Practical Cycles Only Approximate Ideal Cycle Stirling Cycle High Efficiency? • Polymer engines can potentially be much higher efficiency than IC or other conventional engines: • Lower thermal conductivity of polymer walls • No sliding surface friction • No leakage of expanding fluid • Can exploit resonance • Opportunity to use novel or optimally tuned thermodynamic cycles • Expansion pressure controlled electronically; ability to draw power at virtually any point in cycle • Low inertia 20% or more? KDL, IPK NTNU

25. Hybrid Power • Many DoD applications (e.g. robotics, MAVs) require both mechanical and electrical power • Polymer engine with mechanical and electrical output can eliminates entire transducer steps • Fuel cells: chemical  electrical  mechanical • IC Engine + generator + motor: chemical  mechanical  electrical  mechanical • Polymer engine: chemical  mechanical + electrical • Hybrid polymer engine saves parts, weight and is more efficient Combustion inside EAP roll causes linear 23% expansion that could be used for both electrical and mechanical output KDL, IPK NTNU

26. By the Numbers • Polymer engines promise better overall performance than existing electrical and mechanical power sources KDL, IPK NTNU

27. Can it be done?:Polymer Engine First Steps DARPA/ARO program aimed at addressing the key technical challenge – Can a polymer “cylinder” survive combustion? • Successful demonstration of polymer engines operating with high temperature combustion gases (>1000 ºC) for over 3 hrs at 3 Hz • High temperature operation allows for high thermodynamic efficiency • Micro-pitting observed, coatings could prevent pitting • Energy density already similar to batteries (500 Whr/g) • Multiple fuels demonstrated (butane, propane, hydrogen) • External combustion cycle also demonstrated Roll-based Diaphragm-based KDL, IPK NTNU

28. Other Power Applications of EPAMs • Polymer actuators may offer advantages for other power systems • Valves & pumps for fuel cells • Actuated valves for engines, air controls, fuel pumps, etc. Polymer diaphragms can provide large displacements for lightweight pumps Proof-of-principle diaphragm array pump. Dielectric elastomer actuator for direct control of engine valving KDL, IPK NTNU

29. Simple Sensors • Simple low-cost large-strain sensor is a simple embodiment of a generator • Well suited for: • Human motion (Plethysmography, Kinesiology) • Computer input devices for virtual reality applications etc. • General purpose displacement detector for low-cost instrumentation and measurement • Low-cost position, force or pressure sensors for actuators, generators, etc. Large variety of sensors can be based on dielectric elastomers KDL, IPK NTNU

30. Power from EPAM? • EPAMs are promising for addressing a variety of power generation challenges • First proof-of-principle devices made and tested • Variety of transducer configurations • Heel-strike generator • Polymer engine • Improved devices are under development • Lifetime issues are being addressed • Electronics for power management is a key challenge KDL, IPK NTNU

31. Linear generator PISTON MULTILAYER STACK OF ELECTROSTRICTIVE POLYMER ELEMENTS Human-Powered Generators • Large-strain capability of electrostrictive polymers allows for simple and efficient integration into generators • efficiency is not speed dependent • device can weigh 10x less than an electromagnetic generator with the same output rating • Novel generator designs with few moving parts are possible • Similar devices can also be couple to non-human power sources (e.g. engines, wind turbines) HAND CRANK SLIDER MULTILAYER STACK OF ELECTROSTRICTIVE POLYMER ELEMENTS Rotary generator KDL, IPK NTNU

32. MULTILAYER STACK OF ELECTROSTRICTIVE POLYMER ELEMENTS PISTON SLIDER ROTARY ENGINE ENGINE CRANKSHAFT MULTILAYER STACK OF ELECTROSTRICTIVE POLYMER ELEMENTS Linear generator/piston engine combination Rotary generator/engine combination Lighter Generators for Engines • High energy density and large strain capability of EAPs allows for simple, lightweight and efficient integration with combustion engines • Novel engine/generator designs are may be a higher risk/higher payoff alternative KDL, IPK NTNU

33. Wave-powered generators • In August, 2007, the prototype of the buoy type power generation device has been completed and the first experiment has been done in Tampa, Florida. (SRI, EAPM company and Hyper Drive) • Single layer, 58cmx20cm and 100μm in thickness EPAM (40g) can generate 1.8 W electrical energy from a wave 12 cm in height which is repearted once every three seconds (the generation energy from one wave is 5.4J). The energy conversion effiency at this time was about 46%) • It is easy to get more energy using many layers construction. • Advantages: device is simple, no complex mechanical devices, low cost, high efficiency and easy maintenance. KDL, IPK NTNU

34. The buoy for wave-powered generation floating off the coast of Florida. EPAM units are mounted in the center (photo: courtesy of Hyper Drive and SRI International). The black portions are cylindrical EPAMs (photo: courtesy of Hyper Drive and SRI International) KDL, IPK NTNU

35. New wave-powered generators in North Sea • New type of wave-powered generators • New type of tide-powered generators • New wind-powered generators KDL, IPK NTNU

36. Idea for the wave-powered generator(EPAM array) KDL, IPK NTNU

37. Challenges • Low cost, ecological and practical power generation methods. • NTNU’s competence in the field of EPAM both in international and national. • Research and development in actuator, sensors and power generator • Industry applications of EPAM • New materials in EPAM • Electronic system design KDL, IPK NTNU

38. New Renewable Energy Projects • New design • New material • New companies • New applications KDL, IPK NTNU

39. Research and development alliances • NTNU • SINTEF • NN (Norwegian Industries) • SRI (USA) • Hyper Drive (Japan) • Shanghai University (China) • etc KDL, IPK NTNU

40. Funding for pre-project • NTNU • SINTEF • Innovation Norway • NFR • Industries • EU • ? KDL, IPK NTNU

41. Thanking further!! • New revolution or innovation? KDL, IPK NTNU