11/01/05Wave Energy Power Generator2 Presentation Agenda Proposal Feedback –Project Scope...

11/01/05 Wave Energy Power Generator 2

Presentation Agenda• Proposal Feedback

– Project Scope– Target Values

• Concept Evaluation– Concept Screening / Scoring– Design Selection

• Technical Approach– Wave Data Statistics– Mathematical Model & Simulation– Product Architecture / Geometric Layout

• Subsystems– Cable / Reel– Mechanical Rectifier / Gearbox– Generator / Alternator

• Project Budget• Conclusion


Project Scope/Objective• Project Focus: Device that harnesses wave

energy to generate electrical power on a buoy– Off-shore location requires buoy to be self-sustaining

– Power output in the 100’s of Watts range

• Power will be stored in batteries to be drawn from when needed

• Benefits of wave over solar– Higher Energy Densities

– Availability / Reliability


Target ValuesMetric

No.Need Nos.

Metric UnitsMarginal

ValueIdeal

Value

1 1 Power output per cost of unit Watts / $ >.25 >.5

2 2 Power Output Watts > 100 >300

3 3,4 Working Period Months >6 >12

4 3,4,6 Number of moving components Number <6 <4

5 5 Maximum height of wave allowed Feet >2 >6

6 6,8 Number of components Number <8 <5

7 7 Cost of Repair at catastrophic failure Dollars <500 <100

8 6,8 Weight Pounds <200 100

9 8 Size Volume (ft3) <15 <8


Concept Screening1a 1b 2 3 4a 4b 5

NeedCost EffectivenessPower OutputMaintenanceReliability / RobustnessMaximum Wave ConditionsAssembly TimeCost of FailureTransportability

Sum +Sum 0Sum -

Net ScoreRank

Selection Criteria

Reference

Concepts

Relative Performance Rating

Worse than Reference -

Equal to Reference 0

Better than Reference +


Concept Groups (1a & 1b)Buoy

Rotary Generator

Inverted Reduction

Device

Mechanical Rectifier

Reel+ -

Cable

Buoy

Rotary Generator

Inverted Reduction

Device

Mechanical Rectifier

Reel+ -

Cable

Cable

Anchor

Rot. Gen.

Inv. Red. Dev.

Mech. Rect.

Reel + -Buoy

Concept Group 1a

• Reel, Mech. Rectifier, Reduction Device, and Rotary Generator

• Reference

Concept Group 1b

• Device integrated into buoy


Concept Screening

1a 1b 2 3 4a 4b 5

NeedCost Effectiveness 0 +Power Output 0 0Maintenance 0 +Reliability / Robustness 0 +Maximum Wave Conditions 0 0Assembly Time 0 +Cost of Failure 0 -Transportability 0 0

Sum + 0 4Sum 0 8 3Sum - 0 1

Net Score 0 3Rank

Selection Criteria

Reference

Concepts


Concept Groups (2 & 3)Buoy

Crank

Rotary Generator

Inverted Reduction

Device

+ -Crank Arm

Guide

Side View

Buoy

Permanent Magnet Direct Drive Linear Generator

Anchor

Concept Group 2

• Crank, Reduction Device, and Rotary Generator

Concept Group 3

• Piston and Direct Drive Linear Generator


Concept Screening

1a 1b 2 3 4a 4b 5

NeedCost Effectiveness 0 + + -Power Output 0 0 - +Maintenance 0 + 0 +Reliability / Robustness 0 + 0 +Maximum Wave Conditions 0 0 - -Assembly Time 0 + 0 -Cost of Failure 0 - - -Transportability 0 0 0 0

Sum + 0 4 1 3Sum 0 8 3 4 1Sum - 0 1 3 4

Net Score 0 3 -2 -1Rank

Selection Criteria

Reference

Concepts


Concept Groups (4 & 5)Buoy

TurbineConnected to Rotary Generator

Anchor

Check valves

Piston

Anchor

Buoy

Turbine with Rotary Generator

Concept Group 4a&b

• Piston, Fluid, System of Valves, Turbine, and Rotary Generator

• 4a – Closed Turbine

• 4b – Open Turbine

Concept Group 5

• Air Camber, Oscillating Air, Turbine, and Rotary Generator


Concept Screening

1a 1b 2 3 4a 4b 5

NeedCost Effectiveness 0 + + - - - 0Power Output 0 0 - + 0 0 -Maintenance 0 + 0 + 0 - +Reliability / Robustness 0 + 0 + - - +Maximum Wave Conditions 0 0 - - - - -Assembly Time 0 + 0 - 0 0 +Cost of Failure 0 - - - - - -Transportability 0 0 0 0 0 0 0

Sum + 0 4 1 3 0 0 3Sum 0 8 3 4 1 4 3 2Sum - 0 1 3 4 4 5 3

Net Score 0 3 -2 -1 -4 -5 0Rank 2 1 5 4 6 7 2

Continue? Yes Yes No Yes No No Yes

Selection Criteria

Reference

Concepts


Concept Scoring

Relative Performance Rating

Much Worse than Reference 1

Worse than Reference 2

Equal to Reference 3

Better than Reference 4

Much better than Reference 5

Need Weight

Rating Weighted Score




Cost Effectiveness 0.3758 3 1.1274 4 1.5032 1 0.3758 3 1.1274Power Output 0.2695 3 0.8085 3 0.8085 5 1.3475 2 0.539Maintenance 0.1277 3 0.3831 5 0.6385 4 0.5108 4 0.5108Reliability / Robustness 0.1064 3 0.3192 4 0.4256 5 0.532 4 0.4256Maximum Wave Conditions 0.0496 3 0.1488 3 0.1488 2 0.0992 2 0.0992Assembly Time 0.0355 3 0.1065 4 0.142 1 0.0355 4 0.142Cost of Failure 0.0213 3 0.0639 1 0.0213 1 0.0213 1 0.0213Transportability 0.0142 3 0.0426 3 0.0426 3 0.0426 3 0.0426

Total Score (normalized)

RankContinue?

0.969

4No

5

No

1.000 1.244 0.988

2 1 3No Yes

Selection Criteria 31a 1bReference

Concepts


Final Design Selection

• Spring-Reel Buoy Design

• Scored best in top 3 needs– Cost Effectiveness– Power Output– Maintenance

Cable

Anchor

Rot. Gen.

Inv. Red. Dev.

Mech. Rect.

Reel + -Buoy


Two Possible Design Location: 1. Hudson River2. Raritan Bay (Coney Island)

Wave Data Analysis

1

2


Wave Heights Over A Period of 8 days

Period (seconds)

Wave Heights (inches)

Hudson River Data

Histogram of Wave Periods During Typical Hours

Period (seconds)

Frequency (No of Wave Occurrence)

• Mean height is about 6 inches• Maximum is around 20 inches• Minimum is around 1 inch• Mostly ferry-generated waves

•Mean Period is about 2~3 sec•Maximum, 10 sec•Minimum, 1 sec•Majority of data falls between

1~6 seconds

Wave Height

Wave Period


Coney Island, Raritan Bay:Histogram of Significant Wave Heights

0

2000

4000

6000

8000

Wave Height (inches)

Freq

uenc

y

Coney Island, Raritan Bay:Histogram of Significant Wave Periods

0

1000

2000

3000

4000

5000

Wave Period (seconds)

Fre

qu

ency

Raritan Bay DataWave Height

Wave Period

• Hs = 4.0 * sqrt(m0)• Mean Height, 12.2 inches• Maximum, 81.5 inches• Minimum, 1.1 inches• 95% C.L.: 3.94~27.95• 99% C.L.: 2.76~43.30

• Period of the significant waves.• Mean Period, 7.14 sec• Maximum, 19 sec• Minimum, 2.6 sec• 95% C.L.: 3.1~12.8• 99% C.L.: 2.9~14.2


Mathematical Model & Simulation

• Three major design segments relate to several system models• Capturing / following wave motion model developed• In the process of developing mechanical system & electrical system models

Linear to rotary

oscillation

Oscillatory to Unidirectional

Flywheel & Inverted Reduction

Wave

Line

ar O

scill

atio

n

Rot

ary

Osc

illat

ion

Uni

dire

ctio

nal R

otat

ion

Unc

ondi

tione

d E

lect

rical

Pow

er

Hig

her

Spe

ed R

otat

ion

Electrical Conditioning

Con

ditio

ned

Ele

ctric

al P

ower

Motion Capturing

Device

Wave Motion

Mechanical Motion

Mechanical Motion

Electrical Energy

Generator/Alternator

Capture the wave motion

Electricity Generating

DeviceMotion Conversion Device(s)

Flow Chart of Wave Energy Generator

System Model for Simulation

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6 7-8

-6

-4

-2

0

2

4

6

8

0 1 2 3 4 5 6 7

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6 7

)sin( tyw


Assumptions:1. Wavelengths of waves are larger than buoy diameter2. Spring coefficient is constant3. Cable always remains tight4. Generating force is a quadratic function of speed. 5. Damping/drag force similar to an object moving in a

fluid.

yw y’w y’’w

yb y’b y’’b

Fb

W

FgenFspr

Arbitrary reference for yw and yb

FdragAbuoy

Water Line

Wave Motion Model

Force of Buoyancy, Fb

gAyygVF OHbuoybwOHsubb 22 )(

Force of Spring, Fspr.

)( preloadbpreloadbspr yykFkyF

Force from Generator, Fgen

cybyaF bbgen ')'( 2

gengen TF ,

RPMyb ,'

"bdragsprgenb yg

WFFFWF

2)''(2

1bwbuoywaterdragdrag yyACF

Damping/Drag Force, Fdrag0

Governing Equations


Wave Motion Simulation

• Compare Sinusoidal wave input to buoy displacement output

• Model Showed• Overall weight had little effect• Radius of device & reel spring

constant had a greater affect on output

time, sec

Wa

ve

he

igh

t, i

nc

he

s

time, sec

Bu

oy

dis

pla

ce

me

nt,

in

ch

es


PRODUCT ARCHITECTURE

ControlReel

Control Mechanism

Reel

Convert linear motion into two way rotational motionEnclose

Device

Waterproof Device

Casing

Chassis

Provide Structural Support

Hold Device

Store Batteries

Harness wave Energy

Buoy

Rectifier

Rectify Motion into unidirectional rotation

Flow of Force

Flow of signal or Data

Flow of Energy

Gear Box

Speed up rotation of shaft

Rotary Generator

Convert Kinetic Energy into Electrical Energy

Charge Batteries

Anchored cable

Secure buoy position


GEOMETRIC LAYOUT

Anchor

Casing

Cable

Buoy

Gear Box

Rectifier

Batteries

Reel

Rotary Generator


INCIDENTAL INTERACTIONCasing

Chassis

Buoy

RectifierReel

Gear Box Rotary Generator

Anchored cableVibration Vibration, coupling

Thermal ExpansionVibration, shaft

Vibration, coupling

Styling

Friction

Sealing

Control

Torque, RPM

Torque, RPM

Torque, RPM


System Integration: Requirements

Functional Requirements:

1. The device shall charge 12V batteries.

2. The device shall be able to withstand 1 meter waves.

3. The device shall be able to produce at least 100 Watts at average wave conditions.

Non-functional Requirements:

1. The total weight of the device shall be under 200 lbs.

2. The center of gravity shall be at the center of the buoy.

Technical Performance Metrics:

1. Total efficiency of the device (%)

2. Total weight of the device (lbs)

3. The location of center of gravity from bottom center of buoy (inches)

4. Total number of moving parts (number)


Reel Design Considerations• The length of maximum cable

payout will be determined by site conditions.

• The spring must be strong enough for high waves, but not too strong to kill the small waves.

• An oscillating guide may be used to line the cable up.

Reel with a guide even out the cable

Reel Diameter

Large

Less sensitive to radius change

Larger inertia

More need for gearing up

Small

Sensitive to radius change

Less inertia

Less need for gearing up

vs.

http://www.jerseycoastbnt.com/cabo_trolling.htm


What it Does How It Works

Unidirectional Clutch Bearings

Simple gearing mechanism utilizing one-way clutch bearings

Mechanical Rectifier Design

Input

Output

Engages w/ input of CCW

Engages w/ input of CW


Mechanical Rectifier CAD ModelIsometric View

Exploded Top View


Gearbox Concepts & ConsiderationsPlanetary Gearing

• Compact, highly efficient and reliable

Parallel Shaft Gearing• Low part count

Worm Gears• High ratio, compact, very low efficiency

Belt• Inexpensive, low reliability

Optimal gear ratio dependent on generator RPM range

Need for a Flywheel:• Will allow generator to remain around the operational

range where the efficiency is maximum.


Generator/AlternatorMajor Concerns:

• Operate at high RPM

• Low efficiency at low speeds

• High gearing ratio required

• Lower operational RPM is preferred

Alternator is lighter, cheaper and more efficient than generators.

600-W AlternatorAlternator Efficiency vs. RPM


Project BudgetComponent Qty/Unit High ($ ea.) Low ($ ea.) High Total ($/Unit) Low Total ($/Unit)Motor / Generator 1 200 100 200 100Industrial size buoy 1 200 100 200 100Bolted Anchor 1 100 50 100 50Platform 1 90 20 90 20Waterproof Casings 1 100 50 100 50Cable-Reel:

Steel ¼” cable (ft) 20 1 0.5 20 10Reel 1 50 40 50 40

Mechanical RectifierGears 10 5 3 50 30Steel Shafts (ft) 15 20 15 300 225One-way Clutch 2 10 5 20 10Gear and Shaft Grease (tube) 1 8 5 8 5

Gearing SystemPlanetary Gearbox 1 100 50 100 50Bevel Gearing 2 7 5 14 10

Electrical ComponentsMicroprocessor 1 10 5 10 5Wiring (ft) 12 0.1 0.02 1.2 0.24Transformer 1 40 5 40 512V battery for power storage 1 70 50 70 50

O-rings / Sealers 12 0.75 0.5 9 6Check valves 4 8 5 32 20Nuts and Bolts 30 0.25 0.05 7.5 1.5Brackets 6 3 2 18 12

Assembly time at $15/hr (hr) 6 4 90 60Overhead at 20% of Direct Cost 152.97 85.974Totals 1,682.67$ 945.71$


Gantt Chart


Conclusion

• What’s Next– Continue Detailed System Design– Assembly (CAD) Drawing & FEM Analysis– Final Weight and Cost Estimation– Final Report and Presentation

• Team is currently meeting project schedule objective

• Prepare for ME 424


Questions or Comments?

11/01/05Wave Energy Power Generator2 Presentation Agenda Proposal Feedback –Project Scope...

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