Ocean Energy

1. Ocean Energy Kelley Fletcher Dustin Eseltine Ryan Sargent Group 5

2. Ocean Energy • The Need: • With the constant rise in cost of non-renewable energy sources, alternative sources of renewable energy are becoming more important • Energy produced by ocean waves is constant. • Constant energy = infinite supply • Infinite supply = Lower Cost • Objective: • Design a device that converts ocean waves into useable electrical energy

3. Current Solutions • Heaving Floats • Rise and fall of waves causes float to rise and fall creating energy. • Pitching Device • Rise and fall or waves causes the float to pitch • Pitching motion is then converted to energy. Wave Direction

4. Current Solutions • Oscillating Water Column • Waves cause a pressure change inside a chamber. • Oscillating air or water drives energy device (eg. turbine) • Surge Device • -Ocean Waves flow into narrowing chamber • -Water forced into reservoir • -Energy flows through turbine back into ocean.

5. Current Solutions Cont. Archimedes Wave Swing • Passing Waves causes the top chamber to rise and fall • Rise and fall of top chamber cause pressure difference inside device • Pressure difference runs hydraulic motor

6. Current Solutions Cont. Oscillating Water Column • Waves coming into coast cause rise and fall inside chamber • Rise and fall of water in chamber pushes air through turbine. • Dual cycle, needs bi-directional turbine

7. Design Goals • After researching current designs the following design goals were created: • Not a coastal based system. • Not a hydraulic based system. • Make the system scalable. • Design system to be relatively safe from natural occurrences such as storms

8. Anchor System • D-Rings attach buoy to anchoring cables. • The three cables from the buoy are attached to the single cable using a turnbuckle. • This system allows for minor height adjustments after installation. • Single cable attaches to buried concrete anchor.

9. How It Works • Passing waves cause a differential pressure change in a submerged chamber. • The pressure change causes an airflow through a nozzle. • The airflow is used to run a Pelton Turbine. • ½-wave = 1stroke • 2 strokes in a cycle: • Compression • Suction Compression Suction

10. Ocean Hydrodynamics L= Wave Length H= Wave Height D= Water Depth • Note: • One wave = Crest to Crest –or- Trough to Trough • Particle depth is considered a negative value • Design calculations based upon ½wave

11. Ocean Hydrodynamics Cont. • Deep Water • Circular velocity profile • Shallow-Transitional • Elliptical velocity profile • Underwater particle velocities are related to: • Wave Height(H) • Wave Length(L) • Water Depth(d) • Particle depth(z) • Wave Period(T) Particle Velocity Equations

12. Calculating Volumetric Airflow Equation of State – P1V1 = P2V2 -Bernoulli’s Eq. Allowed Psite to be solved. -Once Psite was known the particle velocity equations were substituted for surface and site velocities. Bernoulli’s Equation Substituting for Velocity

13. Volumetric Airflow Cont. Volumetric Airflow -Once Psitewas known, volumetric airflow could be derived. Volumetric Airflow – Q-Bar -Integrating Q gave us Q-bar. Allowing t to be replaced by T/2 (one cycle time.) Q-Bar = Volumetric air flow for one cycle

14. Water Data • Using the National Oceanic and Atmospheric Administration’s website buoy #46212 was chosen. • Data was downloaded from the NOAA website for Wave Height, Wave Period, and Atmospheric Pressure.

15. Ocean Wave Data • Water data was compiled using excel, equations, and buoy data. • Average values were tabulated for each day and then for each month.

16. Volumetric Airflow Data • Volumetric airflow data compiled from buoy data • Average values were compiled daily, monthly, and then yearly. • Yearly values were used for turbine calculations. • Daily values allowed the group to calculate the turbines power output for any day of the year.

17. Power Conversion • Double Acting Turbine • Bi-direction turbine • Possibly self starting • Wells Turbine • Bi-directional Turbine • Not self starting • Blades symmetric to rotation axis • Paddle Wheel Design • Simplistic in operation and construction • Self starting

18. Pelton Turbine • Advanced paddle wheel design • ”Buckets” increase amount of energy extracted from jet stream • Scalable design • Self Starting • Turbine is up to 91% efficient

19. Turbine Calculations • Volumetric air flow was used to calculate the following: • Pitch Circle Diameter (PCD) • Jet Diameter • Jet Area • Jet Velocity Pitch Circle Diameter - PCD determines turbine size Jet Diameter -Jet diameter = Nozzle Diameter Jet Velocity Jet area = cross sectional area of nozzle -Jet velocity is determined from average flow rate and jet diameter.

20. Power Output Turbine Power Output -Shaft work = Theoretical power Output • At 100% efficiency and Flow the Turbine Produces 56.85 Watts • Normal overall system efficiency for Pelton Turbines is 60% • About 40 Watts would be produced at 60% efficiency • Generator is only capable of handling 18 Watts of Continuous power. 12 volts x 1.5 amps

21. Turbine Analysis Using COSMOSWorks, material data, and calculated values a brief analysis was completed. Turbine Max. Deflection – 0.003 in. Max. Stress - 485 PSI Turbine Blades Max. Deflection – 4.2e-04 in. Max. Stress – 56.69PSI Safety Factor - 111 Infinite Life – SLA Model

22. The Prototype Design • Fully scalable turbine system • Submerged design protects device • Power output of one “buoy” = 18 Watts

23. Prototype Design Cont.

24. Project Future The prototype design concept is complete. The next steps in the project are: • 1) Build a prototype model • 2) Prototype would be tested for: • Turbine efficiency, Air vs. Water • Stability • Actual power output • Actual volumetric flow rate • 3) Safety mechanisms may need to be designed to prevent water entering system.

25. Questions? • Thank you for your time.