1. CITRIS sponsored WAVE ENERGY CONVERTER 2013
UC Davis Mechanical Engineering
Alex Beckerman, Kevin Quach, Nick Raymond,
Tom Rumble, Teresa Yeh

2. Contents Introduction Technical Review Construction Next Stage
An overview of the CITRIS Renewable Energy Grant proposal, and project’s scope
Preliminary Design and Research
Technical Review
Terminology and main features of our WEC design.
Subsystems
Buoy
Spar
PTO
Hydraulics
Electronics
Heave Plate
Construction
A comparison of the two hydraulic motors regarding power performance, efficiency, and cost.
Next Stage
Testing in Bodega Bay
Instruction Manual

3. Project Introduction

4. CITRIS introduction 2012 CITRIS Sustainability Competition Winners
$10,000 Renewable Energy Research Grant
(+ $5,400 funding for testing)
Complete project within one year from award

5. Objectives introduction
1. Design and fabricate a Wave Energy Converter (WEC)
2. Use standard parts and components to build the PTO
3. Create a set of instructions and share information over website

6. Preliminary Designs and Research

7. Preliminary design & Research
Potential Test Site: Bodega Bay, Ca
Exposed to Pacific ocean waves and wind swell
Local university facility to assist with deployment
Steep ocean floor topography (bathymerty)
Close proximity to UC Davis
Team has personal knowledge of area
Image: googlemaps.com

8. Preliminary design & Research
Bodega Bay Marine Lab
Source: OceanGrafix.com

9. Preliminary design & Research
Significant Wave Height
NOAA Buoy 46013
NOAA provides ocean data for last 28 years
Buoy anchored 14 miles off shore
Dominant wave period remains constant
Wave height expected to increase closer to shore
Dominant Wave Period
KEY

10. Preliminary design & Research
Bond graph Modeling
Transfers system from mechanical translational domain to the electrical domain
Determines hydraulic damping coefficient for given electrical resistance
Damping coefficient used in state space dynamic modeling

11. Preliminary design & Research
State Space Modeling
Model to represent the dynamics of our physical system in ocean
Linear wave model: approximation of ocean waves as sinusoids. [1]
Equations developed within state space using a free body diagram.
The system is modeled as a two body system with individual forces acting on each
body.
MatLab Simulation for Different Heave plate sizes used in Iteration Process
Free Body Diagram of Buoy- Heave Plate Dynamics

12. Preliminary design and research
[ WEC_001]
[ WEC_002 ]
[ WEC_003 ]

13. Technical Background

14. PTO Buoy Spar Have Plate [ WEC_004 ]
Technical background
PTO
Buoy
Spar
47.3 ft
Have Plate
[ WEC_004 ]

15. SUB-SYSTEMS (BUOY)

16. Buoy

17. buoy Preliminary testing of foam
Fabricated one cubic foot mold out of plywood and wood screws
Filled mold with two part expanding polyurethane foam
Results From Initial Foam Test

18. Buoy
Lining the mold with plastic to assist with releasing the foam from the mold
Positioning the PVC pipes

19. Buoy Marine grade polyurethane foam
Mixture come in two parts, expands when mixed
Final volume is 15 times the original volume after 20 minutes of curing

20. Releasing the foam from the mold
Buoy
Releasing the foam from the mold

21. The foam was cut with a chainsaw to form the 45°chamfer
Buoy
The foam was cut with a chainsaw to form the 45°chamfer

22. The buoy was then sanded down and coated with a pigmented epoxy resin

23. Buoy Steel plates mounted on the upper and lower surfaces of the buoy
All thread compresses the plates and secures buoy to the spar

24. SUB-SYSTEMS (SPAR)

25. spar
Hydraulic

26. spar

27. spar
The bolt holes were drilled on the mill to assist in accurate alignment.
Welded components into framework

28. spar Housing for springs and hydraulic shaft
Wire rope alignment housing

29. SPAR
Addition of strut members

30. SPAR
Strut members welded to the spar
Secured to the buoy bottom plate

31. Spring alignment

32. Alignment brackets
5 spring alignment brackets to keep the 6 springs inline

33. Alignment brackets
Bushing doubles as spring alignment and linear guide for hydraulic rod extension

34. Alignment brackets
Cylinder alignment bracket

35. SUB-SYSTEMS (POWER TAKE OFF SYSTEM)

36. Power take-off system

37. Power take-off system Hydraulic Subsystem elements: Hydraulic Ram
Bladder Type Accumulator
Piston Type Motor
Standard hydraulic hoses and fittings
System Operation:
Direct drive
Reverses direction with each stroke
Accumulator displaces cylinder rod volume

38. Power take-off system Hydraulic Motor Drain Port By-pass: Check valves
Swagelok fittings
Hydraulic subsystem waterproof housing

39. Power take-off system
Power take-off systems conveniently contained within water proof boxes

40. Power take-off system Boxes mount to frame Frame mounts to top of buoy
Easy to access and maintain

41. Power take-off system Permanent Magnet DC Motor:
Operated mechanically to function as a generator
Microcontroller:
Logs system data from voltage and current sensors in 16 MB SD card

42. Power take-off system Waterproof microcontroller housing
Power dissipates in 1500 Watt
1 ohm resistor

43. Power take-off system

44. SUB-SYSTEMS (HEAVE PLATE)

45. Heave plate

46. Heave plate Steel square tubing arranged into framework .
Test fitting before final welding of sheet steel
Supported from spar by connections of steel cables

47. Heave plate Sheet steel limits water flowing around steel frame
Hydrodynamic damping
“Added mass” effect
Sheet steel welded to frame using plug and bead welds

48. Heave plate
Use of four individual modules advantageous for transportation and storage
Plug welds
Bead welds

49. Heave plate Steel cable, clips, and thimbles
Steel cable threads through eyelets welded on steel frame

50. Heave Plate

51. NEXT STAGE (TESTING)

52. Ocean testing
Mooring site at depth of 100 feet

53. Ocean testing Lifting with crane
Ring hoists mounted to bottom of buoy, and section of steel frame
Allows for lifting and transportation

54. Ring Hoists Ocean testing
Ring hoist selected due to ability to lift angled loads
Capacity of 5,000 lbs each

55. Transporting WEC Ocean testing List with 1 Ton crane in EFL
Placed onto trailer provided by EFL
Tow trailer and WEC with a FORD F-550

56. Ocean testing
UC Davis Bodega Bay Marine Laboratory

57. BML Crane BML Boat Ocean testing 3 Ton lifting capacity
15 foot boom span
Drive trailer directly onto dock
BML Boat
Mussel Point Research Vessel
Boat: 42 foot long, with winch system
Specifically designed operate in demanding waters nearshore and offshore

58. Example of a Float Bag and 2,000 lbs Anchor
Ocean testing
2,000 lbs Anchor
Plan A: train axel
(vendor not responding)
Plan B: purchase scrap steel
$0.15/lbs and cut and weld
Plan C: purchase scrap steel
$0.40/lbs and vendor will weld
Float Bag
Plastic bag filled with air
Provided by BML
Can float 3,000 lbs
Will float anchor behind boat
Image provided by BML:
Example of a Float Bag and 2,000 lbs Anchor

59. Data and results Collect data and analyze power output Compile results
Create a manuscript and instruction manual
Upload the instruction manual onto team website
Upload informational videos to website (x5)
Submit final report to CITRIS
Team website
Project Wiki

60. References
A Review of Wave Energy Converter Technology. Drew, B, Plummer, AR and Sahinaya, MN. s.l.: Department of Mechanical Engineering, University of Bath, Bath, UK.
Frequently Asked Questions. US Energy Information Administration. [Online] US Department of Energy, July 9, [Cited: November 20,
Department, Minerals Management. Technology White Paper on Wave Energy Potential on the U.S.Outer Continental Shelf. s.l. : U.S. Department of the Interior, 2006.
Hydraulics: 2X72X1.25 DA HYD CYL Item# Surplus Center. [Online] [Cited: 02 18, 2013.] 72&catname=hydraulic.
McMaster- Carr Supply Company. Plastic Material Properties: More About Plastics. McMaster-Carr. [Online]
McMaster-Carr Supply Company. More About Steel Alloys. McMaster-Carr. [Online]
More About Aluminum and Aluminum Alloys. [Online] [Cited: 04 22, 2013.]
NOAA. NOAA Marine Environmental Buoy Database. National Oceanic and Atmospheric Administration. [Online]
NOAA Ocean Facts. National Oceanic and Atmospheric Administration. [Online] 2011 йил 17- November. [Cited: 2012 йил 10-November.]
Surplus Center. Hydraulics: 4X96X2.25 DA HYD CYL HEAVY DUTY CROSSTUBE. Surplus Center. [Online] [Cited: 02 12, 2013.]
Urethane Technologies Inc. Floating Devices Catalog. Denham Springs, Louisiana, USA : s.n.
US Energy Information Administration. Annual Energy Outlook Renewable Energy Generating Capacity and Generation. Washington DC : US Department of Energy, 2012.
US Energy Information Administration. The Electric Power Monthly with Data for August Washington DC : US Department of Energy, 2012.
Willis, H. L., Welch, G. V., and Schrieber, R. R. Aging Power Delivery Infrastructures. New York : Marcel Dekker, Inc, 2001.

61. Thank you for the opportunity to present our project
Thank you for the opportunity to present our project. We hope you found this information useful. If you have any questions or comments, please feel free to ask.