IntroductionThere is a tremendous amount of energy available in ocean waves (est. 250 TWh/year off the West Coast of the United States), but it is a resource that has yet to be fully explored. All of the current wave energy machines only use the up and down motion of waves to produce energy.

Project Statement: Construct and test a wave energy machine to capture the full elliptical motion of near-surface waves and convert the kinetic energy of the waves to electrical energy.

Motion of fluid particles in ocean waves (source: Essentials of Oceanography, Trujillo)

ResultsGoal #1

Force of Wave On Paddle Body.

A spring scale was attached to the paddle body while it was held in the wave. A drag force of 110 Newtons was measured on the

paddle body head.Goal #2

Verify motion of paddle body in the waves

Success! Motion of paddle body was verified during testing. The paddle follows an elliptical path in the wave

Goal #3Measure the power of the wave energy machine.

The power output can be approximated using force on the paddle body which is translated to torque and the angular velocity of the

input shaft.

𝑃𝑜𝑤𝑒𝑟 = 𝑇 ∗ 𝜔 = 27.5 N*m * 2.7 rad/s = 74 watts

𝑃𝑎𝑑𝑑𝑙𝑒 𝐵𝑜𝑑𝑦 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑃𝑜𝑤𝑒𝑟 𝐶𝑎𝑝𝑡𝑢𝑟𝑒𝑑

𝑃𝑜𝑤𝑒𝑟 𝐴𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒= 30%

Goal #4Prevent Un-Wanted Rotation of the Paddle Body

Because of the conversion from elliptical motion to rotational motion, the paddle body is required to rotate with respect to the

transmission. It was necessary to constrain this rotation so that the paddle body can not freely spin as a result of the waves, as that would cause a decrease in efficiency. The fabricated anti-rotation

bracket was successful in constraining the paddle body.

Design

Paddle-Body• Extends into water

to interact with wave motion

• Multiple fins for increased drag force

Transmission• Convert irregular

motion from paddle body to pure shaft rotation

• Sliding mechanism allows for multiple different shapes of wave capture

Generator• Convert rotation of

transmission shaft to electricity

• Power meter reliably measures power output

Shell and Frame

• Enclose generator for underwater application

• Provide support for machine

Testing the Machine• Conducted at Layton Surf-n-Swim’s Wave Pool• Wave Properties:

Wave period: 2.3 secAmplitude: 0.25 mLength of Paddle: 0.45 m

Poweravailable = 𝜌𝑔2𝐴2𝑇𝐿𝑝𝑎𝑑𝑑𝑙𝑒

8𝜋= 248 Watts

The wave energy machine was tested in the wave pool at Layton Surf-n-Swim. The machine was placed on a cart and then rolled into that water so that it was completely submerged. The waves will ideally push the paddle body into a circular motion which is converted to shaft work through our transmission system and then to electricity using the WindBlue DC-440 generator.

Recommendations1. Because of the massive power of waves the machine needs to be completely fixed in order for the paddle body to move with respect to the machine. The machine will need to be securely anchored in a testing facility so that the waves can be accurately tested.

2. The power output of the generator increases exponentially with rotational speed so a higher gear ratio would be optimal.

3. Orient the machine so it is perpendicular to all incoming waves.

Wave Energy MachineJordan Johnson, Cory Pymm, Sean Troyner, Brian Willhard

Advisor: Dr. Meredith MetzgerDepartment of Mechanical Engineering, University of Utah

Anti-Rotation Bracket

• Keeps paddle body from freely spinning in the wave

• Increases paddle body efficiency