CITRIS sponsoredWAVE ENERGY CONVERTER

2013UC Davis Mechanical

Engineering

Alex Beckerman, Kevin Quach, Nick Raymond, Tom Rumble, Teresa Yeh

CONTENTS Introduction

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

Project Introduction

INTRODUCTION

CITRIS2012 CITRIS Sustainability Competition Winners

$10,000 Renewable Energy Research Grant(+ $5,400 funding for testing)

Complete project within one year from award

INTRODUCTION

Objectives

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

Preliminary Designs and Research

PRELIMINARY DESIGN & RESEARCH

• 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

Potential Test Site: Bodega Bay, Ca

Image: googlemaps.com

PRELIMINARY DESIGN & RESEARCH

Source: OceanGrafix.comhttp://www.oceangrafix.com/chart/zoom?chart=18643

Bodega Bay Marine Lab

PRELIMINARY DESIGN & RESEARCHSignificant Wave Height 1981-

2008

Dominant Wave Period 1981-2008

KEY

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

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

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 eachbody.

MatLab Simulation for Different Heave plate sizes used in Iteration Process

Free Body Diagram of Buoy- Heave Plate Dynamics

PRELIMINARY DESIGN AND RESEARCH

[ WEC_001] [ WEC_002 ] [ WEC_003 ]

Technical Background

TECHNICAL BACKGROUND

Spar

Have Plate

PTO

Buoy

[ WEC_004 ]

47.3

ft

SUB-SYSTEMS(BUOY)

BUOY

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

BUOY

Positioning the PVC pipes

Lining the mold with plastic to assist with releasing the foam

from the mold

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

BUOY

Releasing the foam from the mold

BUOY

The foam was cut with a chainsaw to form the

45°chamfer

BUOY

The buoy was then sanded down and

coated with a pigmented epoxy

resin

BUOY

Steel plates mounted on the upper and lower surfaces of the buoy

All thread compresses the plates and

secures buoy to the spar

SUB-SYSTEMS(SPAR)

SPAR

Hydraulic

SPAR

SPAR

Welded components into framework

The bolt holes were drilled on the mill to assist in accurate alignment.

SPAR

Housing for springs and hydraulic shaft

Wire rope alignment housing

SPAR

Addition of strut members

SPAR

Strut members welded to the spar

Secured to the buoy bottom plate

SPRING ALIGNMENT

ALIGNMENT BRACKETS

5 spring alignment brackets to keep the 6 springs inline

ALIGNMENT BRACKETS

Bushing doubles as spring alignment and linear guide for hydraulic rod extension

ALIGNMENT BRACKETS

Cylinder alignment bracket

SUB-SYSTEMS(POWER TAKE OFF SYSTEM)

POWER TAKE-OFF SYSTEM

POWER TAKE-OFF SYSTEM

System Operation:

• Direct drive• Reverses direction

with each stroke• Accumulator displaces

cylinder rod volume

Hydraulic Subsystem elements:

• Hydraulic Ram• Bladder Type

Accumulator• Piston Type Motor• Standard hydraulic

hoses and fittings

POWER TAKE-OFF SYSTEM

Hydraulic Motor Drain Port By-pass:

• Check valves• Swagelok fittings

• Hydraulic subsystem waterproof housing

POWER TAKE-OFF SYSTEM

Power take-off systems conveniently contained within water proof boxes

POWER TAKE-OFF SYSTEM

• Boxes mount to frame

• Frame mounts to top of buoy

• Easy to access and maintain

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

POWER TAKE-OFF SYSTEM

Power dissipates in 1500 Watt 1 ohm resistor

Waterproof microcontroller housing

POWER TAKE-OFF SYSTEM

SUB-SYSTEMS(HEAVE PLATE)

HEAVE PLATE

HEAVE PLATE

Steel square tubing arranged into framework .

Test fitting before final welding of sheet steel

Supported from spar by connections of steel cables

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

HEAVE PLATE

1. Plug welds2. Bead welds

Use of four individual modules advantageous for transportation and storage

HEAVE PLATE

Steel cable, clips, and thimbles

Steel cable threads through eyelets welded on steel frame

HEAVE PLATE

NEXT STAGE(TESTING)

OCEAN TESTING

Mooring site at depth of 100 feet

OCEAN TESTING

• Ring hoists mounted to bottom of buoy, and section of steel frame

• Allows for lifting and transportation

Lifting with crane

OCEAN TESTING

Ring HoistsRing hoist selected due to ability to lift angled loads

Capacity of 5,000 lbs each

OCEAN TESTING

Transporting WEC

• List with 1 Ton crane in EFL

• Placed onto trailer provided by EFL

• • Tow trailer and WEC with a FORD

F-550

OCEAN TESTING

UC Davis Bodega Bay Marine Laboratory

OCEAN TESTING

BML Boat• Mussel Point Research Vessel

• Boat: 42 foot long, with winch system

• Specifically designed operate in demanding waters nearshore and offshore

BML Crane• 3 Ton lifting capacity

• 15 foot boom span

• Drive trailer directly onto dock

OCEAN TESTING

Image provided by BML: Example of a Float Bag and 2,000 lbs

Anchor

2,000 lbs AnchorPlan 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

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

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, 2012. [Cited: November 20, http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3.

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# 9-7707-72 . Surplus Center. [Online] 2010. [Cited: 02 18, 2013.] http://www.surpluscenter.com/item.asp?item=9-7707 72&catname=hydraulic.

McMaster- Carr Supply Company. Plastic Material Properties: More About Plastics. McMaster-Carr. [Online] 2012. http://www.mcmaster.com/#8574kac/=llhc8n.

McMaster-Carr Supply Company. More About Steel Alloys. McMaster-Carr. [Online] 2010. http://www.mcmaster.com/#88645kac/=llhola.

More About Aluminum and Aluminum Alloys. [Online] 2010. [Cited: 04 22, 2013.] http://www.mcmaster.com/#8975kac/=llhszc.

NOAA. NOAA Marine Environmental Buoy Database. National Oceanic and Atmospheric Administration. [Online] http://www.nodc.noaa.gov/BUOY/.  NOAA Ocean Facts. National Oceanic and Atmospheric Administration. [Online] 2011 йил 17- November. [Cited: 2012 йил 10-November.]

http://oceanservice.noaa.gov/facts/population.html.

Surplus Center. Hydraulics: 4X96X2.25 DA HYD CYL HEAVY DUTY CROSSTUBE. Surplus Center. [Online] 2012. [Cited: 02 12, 2013.]

Urethane Technologies Inc. Floating Devices Catalog. Denham Springs, Louisiana, USA : s.n.

US Energy Information Administration. Annual Energy Outlook 2012- 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 2012. 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.

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.