Global Warming and Impact on ITTC Activities -Energy Saving by Ship Hydro-Aero Dynamics-

National Maritime Research InstituteDirector of Project Teams of Ship Performance Index

Noriyuki Sasaki

Contents

1. CO2 Emission Index - Japanese Proposal -

2. Trend of performance of ships

3. Energy saving devices

4. Simple evaluation method of actual sea performance at initial design phase

5. Conclusions

排出量(百万トン)0 2,000 4,000 6,000 8,000

アメリカ

中国

ロシア

日本

インド

ドイツ

船舶

イギリス

カナダ

韓国

イタリア

メキシコ

フランス

オーストラリア

CO2 Emission from Ships at Operation

•出典）EDMC／エネルギー・経済統計要覧2007年版

・CO2 emission from all ships in the world corresponds to emission from Germany

・CO2 emission from ships tends to increase with growing market of world shipping trade

MEPC57 agreed that the intersessional working group meeting on GHG in Oslo, Norway, should discuss the development of a CO2 design index for new ships.

CO2 Emission Index- Japanese Proposal to IMOANNEX 5

Draft Guidelines on the Method of calculation ofthe new ship design CO2 index

The attained new ship design CO2 index is a measure of ships CO2 efficiency and is:

Wref

NAE

iAEiAEiFAEi

L

kk

NME

iMEiMEiFMEi

M

jj

fVCapacity

PSFCCfPSFCCfindexCOdesignshipNew

××

⎟⎠

⎞⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟

⎠

⎞⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛

=∑∏∑∏==== 1111

2

CO2 from main engine

CO2 from auxiliary engine

• dead weight

• total volume of cargo tanks

• gross tonnage

design ship speed speed loss

actual speed performance

9 fW is a non-dimensional coefficient indicating the decrease of speed in representative sea conditions of wave height, wave frequency and wind speed (e.g., Beaufort Scale 6), and should be determined as follows:

. 1 It can be determined by conducting the ship-specific simulation of its performance at representative sea conditions. The simulation methodology shall be prescribed in the Guidelines developed by the Organization and the method and outcome for an individual ship shall be verified by the Administration or an organization recognized by the Administration.

2 In case that the simulation is not conducted, fW value should be taken from the “standard fW ” table/curve. A “Standard fW ” table/curve, which is to be contained in the Guidelines, is given by ship type (the same ship as the “baseline” below), and expressed in a function of the parameter of Capacity (e.g., DWT). The “Standard fW ” table/curve is to be determined by conservative approach, i.e., based on the data of actual speed reduction of as many existing ships as possible under the representative sea conditions

CO2 Emission Index- Japanese Proposal to IMO

Similar System to Car FOCR Index

Measure Fuel Oil Consumption Rate under metropolitan driving modes

Trend of CO2 Emission from Ships

• 170 vessels built by Japanese Shipyards• Categorized by ship 8 types (Tanker,Container,PCC,BC,etc)• Fuel oil consumption per traffic volume (FOC/(Capacity*Vs))

are investigated

0

50,000

100,000

150,000

200,000

250,000

300,000

0 100 200 300

DW

Loa

bulk

car

cargo

container

oil

ore

ro-ro

その他

Relation between Loa(m) and DW(ton)

container

tanker

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

0 50,000 100,000 150,000 200,000 250,000 300,000

MC

R(kw

)

DW

bulk

car

cargo

container

oil

ore

ro-ro

その他

Relation between DW(ton) and PMCR (kw)

Relation between DW(ton) and PMCR (kw)

(Container)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

0 20,000 40,000 60,000 80,000 100,000 120,000

DW(ton)

PMCR (kw)

0

50

100

150

200

250

300

350

1973 1978 1983 1988 1993 1998 2003 2008

100

150

200

250

300

350

400

1973 1978 1983 1988 1993 1998 2003 2008

Tanker

Container

Trend of Ship Length (Lpp) 1975-2005

VLCC

AFRAMAX

PANAMAX

ULCC

13.5

14

14.5

15

15.5

16

16.5

17

1970 1975 1980 1985 1990 1995 2000 2005 2010

Tanker

15

20

25

30

1973 1978 1983 1988 1993 1998 2003 2008

Container

Trend of Ship Speed (kts) 1975-2005

Trend of Design Froude Number 1975-2005

0.150 

0.200 

0.250 

0.300 

0.350 

1973 1978 1983 1988 1993 1998 2003 2008

0.1

0.125

0.15

0.175

0.2

1970 1975 1980 1985 1990 1995 2000 2005 2010

Tanker

Container

ULCC

0

0.05

0.1

0.15

0.2

1973 1978 1983 1988 1993 1998 2003 2008

Trend of FOC Index of Large Tankers built by Japanese Ship Yards

sec)/(*/mtondaykg

turbine

13.5

14

14.5

15

15.5

16

16.5

17

1970 1975 1980 1985 1990 1995 2000 2005 2010

Tanker

Correction of Vs

Correction of Vs + ship length

0.100 

0.150 

0.200 

0.250 

0.300 

0.350 

0.400 

0.450 

1973 1978 1983 1988 1993 1998 2003 2008

Trend of FOC Index of Large Containers built by Japanese Ship Yards

sec)/(*/mtondaykg

15

20

25

30

1973 1978 1983 1988 1993 1998 2003 2008

Container

Conclusions 1

• Both container ships and tankers, FOC index trend is almost the same except 1995 after

• The different tendency may be brought by the fact that there are no effective energy saving devices for high speed containerships.

• It is also obvious that design ship speed of container ship is not so reliable compared with tanker’s case.

total loss

Energy Loss of a conventional ship

wave resistance

momentum lossviscous lossrotational loss

rudder resistance

viscous resistance

momentum lossviscous lossrotational loss

rudder resistance

Energy Loss of a conventional ship

propulsion loss

Recovered by PropellerThrust deduction

Energy Loss at Ship Navigation

wind resistance

So complicated !

LV-Fin (IHI) 1995DPF (Sumitomo) 1992

Horizontal Fin in front of a propeller

1. Pressure recovery by preventing down flow

2. Induction of bilge vortex to propeller disc

SSD (Universal) SILD (Sumitomo )

Accelerating duct in front of a propeller

1. Pressure recovery by preventing down flow

2. Thrust due to duct

3. Induction of bilge vortex to propeller disc

Scale effect on SILD Performance

-0.01

0.00

0.01

0.02

0.03

0.02 0.04 0.06

Δw

Δ(1

-t)

Small Model

Large Model

SHIP

Scale Effect of energy saving duct

Lpp=2m

Lpp=8m

Lpp=250m

1-2%

4-5%

7%

Improvement of (1-t) may be originated from reduction of section drag of duct due to Rn effect.

(average of 12ships with & 10 ships w/o)

Magnitude of Energy Saving for each device

Recovery of Propeller Energy Loss

Red

uctio

n of

Hul

l/Rud

der r

esis

tanc

e &

Duc

t Thr

ust

２

％

３

％ ４

％

５

％

６

％

７

％

８

％

Energy saving device in future

Conclusions 2

•Owing to effective energy saving devices invented by shipyards, FO index of tankers/bulk carriers were much improved in these 20 years.

•Energy saving device in future will have multifunction such as a duct installed in front of a propeller

•CFD will be a good tool to investigate mechanism however, it will be another several years to utilize as a design tool.

•It is very regrettable that there are no effective energy saving devices for containerships which are the most important ships from a global warming view point.

0

4

2 4 Wave height（ｍ）

Spee

d L

oss(

Kno

t

）

◆

Shipyard A▲

Shipyard B○

Shipyard C■

Shipyard D

Calm Sea

Example of Ship Performance at Actual Sea

• Speed loss is not the same even if the ships was designed under the same specification

0

2 Due to ship design

速力変更

ハイブリッド計算手法

Detail of Computation Flow

Tank test

Calculation

Design Index

SHP = constant

Yes

Resistance/Propulsion Test

in still water

Resistance in still water

air resistance

Total resistance

Required thrust

thrust deduction

Propeller loading

Propeller Efficiency

Propeller efficiency

relative rotative efficiency

Hull efficiency

Propulsive Effciency

Delivered Power

Shaft Power

SHP(wave)＝SHP

Speed Loss

Ship motion in regular wave

Resistance in regular wave spectrum

Resist. in short crest irregular wave

Effective horse power

M/E performance

Fuel Oil Consumption

Ship Speed =const

BFSpeed Loss)

Iterated Process

Linearization 2

Simplified Method

波浪中抵抗増加計算

船体斜行・あて舵計算

波浪中自航計算

波浪中馬力計算

波浪中船速低下計算

主機燃料消費

理論計算の補正

Cal. of Resistance in Waves

Effect of Wind Resistance

Propulsive Efficiency

Required Power in Waves

Speed Loss due to Waves

Fuel Oil Consumption

Correction based on Model Test

Design Index of Ship Performance

Linearization 1

hull Form

J

KT

KQ

POWC

Simplified Method can be used at initial design phase where we hardly get the detailed information for the designed vessel.

平水中模型試験

正面規則波抵抗試験

Resistance Test

Resistance Test in Regular WaveEmpirical Formula

)1(21* 8.0

22

1 Ba FnCBBfcpgCRaw += ζρ

Simplified Method by EXCEL Calculation

Head Wind

13.50

14.00

14.50

15.00

15.50

16.00

16.50

1 2 3 4 5 6 7 8

Beaufort Sca le

Ship

Speed(k

ts)

Voyage Data

CAL by Hope

Simplified Method of Added Resistancein Wavekind of Ship ContainerCapacity 6500 TEULpp 300 mB 40 mD 24 mｄ 14 mCb 0.65Disp 111930 tonCp 0.658LCB 0.59 %Lpp

Af 1548 m**2

Dp 8.8 m

1-t 0.831-w 0.73Vs 26.0 24.7 23.4 ktsEHP 37,735 30,926 26,064 KWBHP 51,786 41,981 35,195 KWCal of Ship Speed in actual seaVs 26.0 24.7 23.4Ro 287790 248268 220864Cp 0.658δCp 0.0285Cpf 0.644Bfcp2 0.034Fnb 0.676 0.642 0.608C1 1.00C2 31.28Raw(regular) 37210 35776 34328Raw 18605 17888 17164C0 0.60Raa 28370 27406 26442To 345403 297970 265080To+δT 401782 352331 317415Ct 1.140 1.090 1.080Ct' 1.326 1.289 1.293ηo'/ηo 0.975 0.973 0.971 929.8008BHP' 61762 51004 43388δVs -1.19Vs (result) 24.8δP'/P 19% 21% 23%fw 0.954

Power Curves(calm)

Input items

(1) Principal dimensions of ship

(2) Power curves (3 points)

(3) Self propulsion factors

(4) Frontal area of superstructure

Effect of measurement position on wind velocity

Conclusion

• Design Index of CO2 emission for individual ship was proposed to IMO and this proposal will be accepted

• Simulation or prediction tool for CO2 emission at actual sea is very important and the tool should be simple and robust.

• New idea of energy saving device for high speed ship such as containership is burning issue.

• Energy saving devices for slow speed vessels such tankers should be deeply investigated. Especially, scale effect and performance in wave are important.

• Resistance increment due to wind at navigation is not clear and full scale measurement will help us to understand.