technical report ver08 final - cds€¦ · b final version project team crs/anh cds 18-11-2015 a...

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GREEN SHIP OF THE FUTURELOW EMISSION ROPAX FERRY STUDY

Technical report

Technical Report

“Low emission Ro-Pax ferry study”

Author(s): Project team

Edited by: Magnus Gary & Christian Schack

Date: November 2015

Approved by: Claus Daniel Simonsen

B Final version Project

team CRS/ANH CDS 18-11-2015

A DRAFT – issued for comments Project team

MAGA/CRS CDS 03-11-2015

Revision Description By Checked Approved Date

Keywords:

Classification:

Open

Internal

Confidential

Green Ship of the Future

MAGA/CRS Green Ship of the Future Low emission Ro-Pax ferry study

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INDHOLD SIDE

1.INTRODUCTION ...................................................................................................................... 1

2. OBJECTIVE ............................................................................................................................ 1

3.PROJECT PARTNERS ............................................................................................................... 2

4.REFERENCE VESSEL ................................................................................................................ 2

5.ROUTE, OPERATION AND SPEED PROFILE ............................................................................. 4

6.ASSUMPTIONS ........................................................................................................................ 7

6.1 Emissions ................................................................................................................... 7 6.2 Optimum fuel based on availability and price .................................................................. 7

7.GENERAL DESIGN OF THE NEW LOW EMISSION RO-PAX FERRY .......................................... 9

7.1 Main Particulars ........................................................................................................... 9 7.2 Fuel and propulsion ..................................................................................................... 9 7.3 Cargo handling ........................................................................................................... 11

8.HULL OPTIMISATION ........................................................................................................... 13

8.1 Method ...................................................................................................................... 13 8.1.1 RANS based CFD calculations ................................................................................... 13 8.1.2 Parametric optimisation by the FRIENDSHIP framework............................................... 14 8.2 Results for original hull form ........................................................................................ 14 8.3 Results for optimised hull form ..................................................................................... 15 8.4 Speed and power prediction ......................................................................................... 17 8.5 Environmental impact.................................................................................................. 18

9.WEIGHT OPTIMISATION GROUP ......................................................................................... 19

9.1 Methodology .............................................................................................................. 19 9.1.1 Moveable decks’ weight and space requirements ........................................................ 19 9.1.2 Deck girder and transverse heights ........................................................................... 20 9.1.3 Steel superstructures ............................................................................................... 20 9.1.4 Vehicle decks .......................................................................................................... 21 9.1.5 Hull steel weight ..................................................................................................... 22 9.2 Environmental impact.................................................................................................. 24

10.MACHINERY AND FUEL SELECTION ................................................................................... 25

10.1 Method and calculations .............................................................................................. 25 10.1.1 Route, operation and speed profile ............................................................................ 25 10.1.2 Safe Return to Port ................................................................................................. 25 10.2 Fuel alternatives, benefits and disadvantages................................................................. 26 10.2.1 HFO with scrubber .................................................................................................. 27 10.2.2 Marine Gas Oil (MGO) .............................................................................................. 27 10.2.3 Liquefied Natural Gas (LNG) ..................................................................................... 28 10.2.4 Methanol ................................................................................................................ 29 10.2.5 Dimethyl Ether (DME) .............................................................................................. 30 10.2.6 Optimum fuel based on availability, price and emissions .............................................. 30 10.3 Fuel storage and treatment requirements ...................................................................... 30 10.3.1 Heavy fuel Oil (HFO) ............................................................................................... 30 10.3.2 Liquefied Natural Gas (LNG) ..................................................................................... 30 10.3.3 Methanol ................................................................................................................ 31 10.4 Machinery selection..................................................................................................... 32 10.5 Machinery alternative 3 – DE Azipod CRP ...................................................................... 36 10.6 Power supply in harbour .............................................................................................. 38



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10.6.1 Shore power ........................................................................................................... 38 10.6.2 Harbour generator................................................................................................... 39 10.7 Waste Heat Recovery (WHR) ....................................................................................... 39 10.7.1 Waste heat available ............................................................................................... 39 10.7.2 Thermal power ....................................................................................................... 39 10.7.3 Electrical power ...................................................................................................... 40 10.7.4 Combined cycles ..................................................................................................... 40 10.7.5 Rankine cycle (steam turbine generator) .................................................................... 40 10.7.6 ORC Organic Rankine Cycle (turbine generator driven by an organic fluid) ..................... 41 10.7.7 TCS-PTG (Turbo Compound System with Power Turbine and Generator) ....................... 42 10.8 LNG charge air cooling ................................................................................................ 44 10.9 Variable Speed Drives (VSDs) ....................................................................................... 45 10.9.1 Technical description of temperature and load controlled VSD for cooling water systems . 45 10.9.2 Design data ............................................................................................................ 46 10.9.3 Savings with temperature and load controlled VSD...................................................... 47 10.9.4 Technical description of VSD controlled engine room ventilation system ........................ 48 10.10 DC-Grid .................................................................................................................. 48 10.11 Fuel costs and CAPEX .............................................................................................. 51 10.12 Emissions ............................................................................................................... 52 10.13 EEDI ...................................................................................................................... 53 10.14 Results and conclusion ............................................................................................. 54 10.14.1 LNG as fuel ......................................................................................................... 54 10.14.2 CRP propulsion .................................................................................................... 55 10.14.3 Shore power ....................................................................................................... 56 10.14.4 Harbour generator ............................................................................................... 56 10.14.5 Waste Heat Recovery (WHR) ................................................................................ 56 10.14.6 LNG cooling ........................................................................................................ 56 10.14.7 Variable speed drives (VSDs) ................................................................................ 57 10.14.8 DC-Grid .............................................................................................................. 57 10.15 Environmental and economic impact ......................................................................... 58

11.HVAC OPTIMISATION ......................................................................................................... 59

11.1 Correct system design ................................................................................................. 61 11.2 Correct product design ................................................................................................ 61 11.3 Accommodation results ............................................................................................... 61 11.3.1 AC 1, Deck 9, MVZ 3................................................................................................ 62 11.3.2 AC 2 and 5, Deck 9 and 8, MVZ 2.............................................................................. 63 11.3.3 AC 3, Deck 9, MVZ 1................................................................................................ 64 11.3.4 AC 4, Deck 8, MVZ 3................................................................................................ 65 11.3.5 AC 6, Deck 8, MVZ 1................................................................................................ 66 11.3.6 AC 7, Deck 7, MVZ 3................................................................................................ 67 11.3.7 AC 8, Deck 7, MVZ 2................................................................................................ 68 11.3.8 AC 9, Deck 7, MVZ 1................................................................................................ 69 11.3.9 Technical cooling .................................................................................................... 70 11.3.10 Accommodation and cooling systems in total .......................................................... 71 11.4 Engine room ventilation ............................................................................................... 73 11.5 Cargo fans (trailer deck ventilation) .............................................................................. 74 11.6 Environmental impact.................................................................................................. 75

12.LIGHT OPTIMISATION ....................................................................................................... 76

12.1 Methods .................................................................................................................... 76 12.2 Environmental impact.................................................................................................. 77

13.TECHNICAL CONCLUSION .................................................................................................. 78

14.COLLABORATIVE DEVELOPMENT ....................................................................................... 80



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14.1 The project ................................................................................................................ 80 14.2 The process ............................................................................................................... 80 14.3 Workshop 1 ............................................................................................................... 82 14.4 Workshop 2 ............................................................................................................... 82 14.5 Workshop 3 ............................................................................................................... 83 14.6 Workshop 4 ............................................................................................................... 83 14.7 Summary ................................................................................................................... 84

15.ACKNOWLEDGEMENT ......................................................................................................... 85

16.REFERENCES ....................................................................................................................... 86

17.TABLE OF TABLES ............................................................................................................... 87

18.TABLE OF FIGURES ............................................................................................................. 88



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1. Introduction In the spring 2011, the private-public partnership Green Ship of the Future initiated a 'low-emission' ferry study. It was agreed to carry out the study as a collaborative development study involving partners from the entire maritime industry working together on optimising a ferry for a given operation. In order to achieve this, a facilitator was brought in and given the task of obtaining the desired synergies within the project group In order to benchmark the findings, the existing Ro-Pax ferry M/F VISBY was used. This ferry is currently operated by Gotlandsbolaget between the harbour in Visby at the Swedish island Gotland and mainland Sweden. Gotlandsbolaget has several years’ experience with operating this route and has an extensive database of energy consumption on board the vessels whereby benchmarking of potential emission reductions is possible.

During the study, the study partners have contributed through subgroups where their technical expertise could contribute. Finally, the main findings obtained through the group efforts are presented in this technical report.

2. Objective The overall objective of the study has been to provide an insight into what can be done in order to reduce emissions from ferries. In this regard, the study has aimed at utilising and sharing technical and operational expertise among all the study partners. The technical target of the study has been to reduce the CO2 emissions by 25% compared to the (well-designed) ferry already in operation between Gotland and Sweden. The technological and political environment in the maritime world continuously changes the possibilities and requirements. Therefore, the design aim of this environmentally friendly Ro-Pax concept has been to be ready for order before 2020. In this context, it is relevant to mention that some findings can be implemented as retro-fit in existing vessels. Technically speaking, the study has focused on elements relating to design, machinery, propulsion, alternative fuels and other areas affecting emissions. But in order to combine the technical findings in the best way possible, a certain focus on the “softer” issues such as knowledge sharing and collaboration has been necessary. In this regard, focus has been on exchanging knowledge among the partners and utilising the shared knowledge in the optimisation process. This might seem elementary, but given the borders between businesses, this has been a greater obstacle which has demanded extra focus. The study partners have not been promised any payback on their contributions. But the Danish Maritime Fund has been supporting the coordination of the study financially.



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3. Project partners The study has been performed by the following Danish companies which are all members of the Danish private public initiative Green Ship of the Future:

� ABB � Cavotech � Danfoss � Desmi � DNV � FORCE Technology � Johnson Controls � Lloyd's Register � Maskinmesterskolen i Aarhus � Novenco � OSK-ShipTech � RockWool � Scanel � SPX (APV)

Furthermore, the project has received valuable input and support from Rederi AB Gotland.

4. Reference vessel The reference vessel is a Ro-Pax vessel delivered in 2002 by the Chinese shipyard Guangzhou Shipyard International (GSI) and designed in 1998 by Knud E Hansen A/S in Denmark

Figure 1 M/F Gotland – The reference vessel



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The original vessel was designed with the following main particulars and main engines (diesel):

Length 195,0 m Breadth 25,0 m Draught 6,4 m Speed 28,5 knots Passenger capacity 1500 PAX Trailer Capacity 1750 Lane meter

Main engines 4 x Wärtsila 12V46 Installed ME power 50,400 kW Aux. engines 3 x Wärtsila Installed Aux. power 4,560 kW

Table 1 Main particulars and engine data This vessel has been used for benchmarking in this study as the new design is to replace the existing vessels on the route between Nynäshamn and Visby (Gotland) and the route between Oskarshamn and Visby.



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5. Route, operation and speed profile In order to find the operational profile of the Ro-Pax ferry, the schedule throughout a full year was analysed with departures from both Nynäshamn and Oskarshamn to Visby.

Figure 2 Map of routes

Date Nynäshamn-Visby Oskarshamn-Visby

Distance [nm] 78 65

Departures per year [-] 788 465

Table 2 Distance and compilation of route schedule This is taken directly from the route schedule of the two vessels going in traffic to Visby. Speed plots of the Nynäshamn-Visby route (78 nm) are displayed below. The Oskarshamn-Visby route (65 nm) takes approximately the same time, but at lower speed. The cruising speed for the Nynäshamn-Visby route is approximately 28.5 kn.

Figure 3 Speed plot of Nynäshamn-Visby route



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From the speed plot, it is possible to see that the vessel spends around 15 minutes manoeuvring on departure before reaching its transit speed and on arrival slows down before docking. This gives the following operational profile.

Figure 4 Operation profile Nynäshamn-Visby route The propulsion power and the electric power have been estimated according to the below table. The propulsion power is derived from the speed-power curve of the vessels, and the electric power is the shipowner’s own measurements. We have assumed that the vessel will have 360 operation days every year as there will be some maintenance requirements from time to time.

Time spent in mode while active

Operation days a year

Time [%]

Time [h]

Propulsion Power [kW]

Electric Power [kW]

Transit 360 39% 3,404 38,000 2,100 Manoeuvring 360 7% 601 20,000 2,500 Port Operations 360 54% 4,635 0 1,200 Total 360 100% 8,640

Table 3 Operation modes and power requirements Five days are estimated off-hire due to maintenance activities. With this operational profile and power consumption, the following power consumption profile could be observed. This means that approximately 94% of the fuel is consumed by the main engines with connected shaft generators (transit + manoeuvring).

39%

7%

54%

Transit

Manoeuvring

Port operations

Operation profile



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Figure 5 Power consumption profile As the ferry is serving an island, the volume of cargo varies over the year. During the summer, the vessel is fully loaded, and in offseason, the load is considerably lower. With the current operation, the vessels are more than half the time in port and sailing only 39% of the time.

86%

8%6%

Fuel Consumption Profile

Transit

Manoeuvring

Port Operations



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6. Assumptions The findings in this report are dependent on a set of assumptions. These assumptions are described below.

6.1 Emissions The emission calculations have been based on the IMO conversion factors for different fuels. This means that one tonne of Heavy fuel oil will emit 3.114 tonne of CO2. As this carbon conversion factor was not available for methanol, a molar mass calculation has been made in order to find the correct factor.

Type of fuel Reference Conversion factor

Diesel/Gas Oil ISO 8217 Grades DMX through DMB 3.206

Heavy Fuel Oil ISO 8217 Grades DMX through DMB 3.114

LNG ISO 8217 Grades DMX through DMB 2.75

Methanol Molar mass calculations 1.373

Table 4 IMO carbon conversion factors /8/ Just by using the conversion factors for LNG, the emissions would be reduced by more than 14%. In addition, LNG and dual fuel engines will have a lower specific fuel consumption which will reduce the CO2 emissions further to around 25%. The CO2-equivalent reduction will be lower due to the methane slip in the dual fuel engines.

6.2 Optimum fuel based on availability and price The graph below shows the relative price difference per energy unit ($/MJ) between the different alternatives. In addition, the relative volume requirements for the same energy content are shown as the green line on the secondary y-axis. Please note that the volume on the secondary y-axis includes the extra volume required by the tank insulation, the tank space requirements and the cold box for LNG or the cofferdams for methanol or the cofferdams and methanol conversion space for DME.



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Figure 6 Price and volume of different fuel alternatives

* An assumption of 10% mark-up has been calculated for DME compared to methanol as methanol is the feedstock. This is due to the energy loss in the conversion process between DME and methanol. This figure is not an exact reference.

HFO and scrubber, LNG and methanol will be investigated further in the project. These are also the three cheapest fuels in this comparison.

Fuel HFO LNG Methanol

Price $/MT 700 840 440 LHV MJ/MT 40.5 49.2 19.93 Price $/MJ 0.017 0.017 0.022

Table 5 Fuel prices used in calculations

0,0

0,5

1,0

1,5

2,0

2,5

60%

70%

80%

90%

100%

110%

HFO MGO LNG Methanol DME

Volume

Price

Price compared to MGO* Volume requirements compared to MGO



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7. General design of the new low emission Ro-Pax ferry The purpose of the group General Design has been to coordinate and distribute knowledge related to the layout and operation of the existing vessel. The group have further been responsible for updating the General Arrangement to the new requirements from Gotlandsbolaget and implementing findings by the working groups into the design. Participants in this sub group was:

� DNV � OSK-ShipTech

7.1 Main Particulars Gotlandsbolaget required that the new design included an increased number of passengers, hence the accommodation area was to be increased in the new design. This as well as requirements in relation to alternative fuel required an increased length. Further, the additional accommodation space led to an increased centre of gravity for the vessel. Initially in the study, the team expected the vessel’s breadth to be 0.6 m wider than the existing vessel due to stability requirements including new rules such as safe return to port. But as a consequence of the weight group’s work and identification of possible savings, it was possible to keep the vessel’s breadth at the original 25 m.

Existing vessel Low emission vessel design

Length m 195,00 198,54 Breadth m 25,00 25,00 Draught m 6,40 6,40 Speed knots 28,5 28,3 Passenger capacity PAX 1500 1930 Trailer Capacity Lane meter 1750 1746

Table 6 Main particulars for existing vessel and new low emission vessel design

7.2 Fuel and propulsion The new design has tanks for operation on both Methanol and LNG and is fitted with a diesel electric propulsion system including a counter rotating Azipod unit aft of the centre line main propeller.



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Figure 7 The counter rotating Azipod unit version of the vessel Fuel tanks are arranged below the main deck in two compartments in front of the main engine’s methanol tanks. This requires a cofferdam protection which is arranged starboard and portside of the LNG tanks.

Figure 8 The counter rotating Azipod unit version of the vessel – MA in profile The savings identified made it possible to reduce the power requirement and arrange the new design with only 4 main engines and no auxiliary power. The layout has the 4 main engines arranged in two separate compartments for fulfilling safe return to port and stability requirements.

Figure 9 The counter rotating Azipod unit version of the vessel – MA in planview



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Figure 10 The counter rotating Azipod unit version of the vessel – MA in planview – tank top

7.3 Cargo handling The Azipod solution required a service space on the main deck. This, however, was in conflict with the original ramp layout. Consequently, access to the upper deck is now handled via land based ramps as the existing design included ramps between main deck and upper deck in both starboard and port side of the main deck. By changing the ramp philosophy, it is possible to accommodate the Azipod service space and have access to the main deck via ramps in both port and starboard side.

Figure 11 Ramp arrangement - Upper deck



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Figure 12 Ramp arrangement - Main deck Based on the general design as presented above, the remaining subgroups have worked on finding the most efficient technical solutions. These are presented below.



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8. Hull optimisation Normally, hull forms are designed and optimized for operation at one speed and one draught. But in reality, however, most ship types are not constantly operating at the design point as the speed and loading conditions vary during operation. This is important to take into account in the hull optimisation process as the hull form must perform well in all conditions. If this is neglected, the shipowner will pay a ‘penalty’ in terms of disproportionally high fuel consumption. To avoid this ‘penalty’, FORCE Technology optimised the hull form on the basis of the operational profile, the requirements from Gotlandsbolaget and the assumptions implemented in the study.

Participants in group: FORCE Technology Support and dialogue with: General Design group, i.e. OSK-Shiptech and DNV

8.1 Method FORCE Technology has performed a viscous CFD study and parametric optimisation of the flow around the Ro-Pax ferry. Information from Gotlandsbolaget was used to optimise the hull form, taking into account the large differences between draughts during summer and winter operation. By weighting the results from the different draughts, an optimised hull geometry could be selected.

8.1.1 RANS based CFD calculations The viscous CFD calculations were conducted with the RANS code STAR-CCM+ 7.06.009. The calculations were done in model scale (1:26.67). The condition was a bare hull condition, and further, only one side of the hull was considered due to centre plane symmetry. A symmetry boundary condition was applied at the centre plane.

The RANS calculation was conducted for three draughts selected based on the existing ferry operation. The considered draughts are 5.87 m, 6.05 m (design, highest weight in operational profile) and 6.23 m. The calculations at all draughts were carried out at one speed equal to 28.3 knots. Calculations have also been made for the existing vessel to serve as a reference, but these calculations will not be presented in this report. These calculations are performed at 28.5 knots as this is the operational speed for the existing ferry. The results of the calculations have been evaluated by means of:

� Hull surface pressure � Wave pattern � Limiting streamlines on hull � Estimated resistance and power



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8.1.2 Parametric optimisation by the FRIENDSHIP framework The optimisation by the FRIENDSHIP framework is performed by setting up a partially parametric model. The model is based on the initial hull form (model 20). A number of design variables are then defined controlling the automatically generated hull forms. The deformations are performed both in the aft- and fore-body. The generated hull forms are evaluated by the RANS CFD code STAR-CCM+, see further information above. The calculations performed in conjunction with the FRIENDSHIP optimisation are run with a coarse mesh approach in order to reduce calculation time. Calculations were performed at 3 draughts and 1 speed for all generated hull forms. The following weighting was used:

Draught [m] Weighting [%] 5.87 25.5 6.05 48.2 6.23 26.3

Table 7 Draughts and weighting The weighted effective power is defined as: PE,weighted = 0.255 PE,T=5.87m + 0.482 PE,T=6.05m + 0.263 PE,T=6.23m First, the initial hull form is evaluated to serve as a basis for the optimisation. This initial hull form is a modified version of the existing ferry, slightly longer and aft body changed to have a different propulsive layout, now having a centre propeller with contra rotating Azipod behind. The initial hull form (model 20) is then optimised by the FRIENDSHIP framework coupled to the RANS solver STAR-CCM+.

8.2 Results for original hull form Three RANS CFD calculations were made for the initial hull form (model 20) at 5.87 m, 6.05 m and 6.23 m even keel, all for a speed of 28.3 knots. Looking at the plot in Figure 13, it can be seen that the bulbous bow is actually performing quite well. A fairly large stern wave pattern can be seen which is typical for the quite high Froude number. The results of the RANS CFD calculations are shown below:



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Version Model 20 Model 20 Model 20 Speed [knots] 28.3 28.3 28.3 Draught [m] 5.87 6.05 6.23 Water Depth [m] Infinite Infinite Infinite Dyn. Trim [deg] -0.098 -0.122 -0.136 Dyn. Sinkage [m] -0.406 -0.398 -0.393 RT,model [N] 100.901 103.489 106.001 RT,ship [kN] 1347.2 1382.1 1414.1 PE,ship [kW] 19613.3 20121.8 20587.4 Ca [-] 1.50E-04 1.50E-04 1.50E-04 Form factor [-] 1.00 1.00 1.00

Table 8 Calculated (RANS CFD) resistance, effective power and dynamic sinkage and trim* *Model resistance extrapolated to full scale using ITTC-57 method. Analysed with a form factor as indicated in the table and a correlation allowance factor of 1.50E-4. A negative value of trim corresponds to ‘bow down’ trim.

Figure 13 Example of CFD plot. Initial hull form (Model 20), wave pattern, 5.87 m draught

8.3 Results for optimised hull form A large number of different hull forms have been investigated by RANS CFD utilizing the FRIENDSHIP framework for hull form generation and search for optimal hull form. Below the results for the most promising hull form are summarized. Looking at the plots in Figure 14 and Figure 15, it can be seen that the wave making has been slightly reduced compared to model 20, especially the trough at the forward shoulder is reduced. The results of the RANS CFD calculations are shown below and show that the resistance is reduced



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between 3.8% and 1.2%. Including the weighting presented above, the weighted effective power has been reduced by 2.4% corresponding to an effective power of 492.2kW.

Version Des0032 Des0032 Des0032 Speed [knots] 28.3 28.3 28.3 Draught [m] 5.87 6.05 6.23 Water Depth [m] Infinite Infinite Infinite Dyn. Trim [deg] -0.086 -0.106 -0.120 Dyn. Sinkage [m] -0.409 -0.403 -0.399 RT,model [N] 99.059 101.742 104.286 RT,ship [kN] 1295.9 1348.1 1397.6 PE,ship [kW] 18866.0 19626.6 20347.7 Ca [-] 1.50E-04 1.50E-04 1.50E-04 Form factor [-] 1.00 1.00 1.00 Difference PE vs. model 20 [%]

-3.8% -2.5% -1.2%

Table 9 Calculated (RANS CFD) resistance, effective power and dynamic sinkage and trim* *Model resistance extrapolated to full scale using ITTC-57 method. Analysed with a form factor as indicated in the table and a correlation allowance factor of 1.50E-4. A negative value of trim corresponds to ‘bow down’ trim.

Figure 14 Example of CFD plot. Optimized hull form (Des 032), wave pattern, 5.87 m draught



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Figure 15 CFD plot comparing initial and optimised hull forms (Model 20 and Des 032), wave pattern, 5.87 m draught

8.4 Speed and power prediction Based on the RANS CFD calculations, a speed and power prediction was made for the optimised hull form. The prediction of the residual resistance coefficient Cr was done by performing RANS CFD calculations at 1 speed (28.3 knots) at T=6.05 m. On the propulsive side, open water data provided by ABB was used. The wake fraction was based on the RANS CFD calculations. Thrust deduction and relative rotative efficiency were estimated based on the FORCE in-house database. The power split between the forward and aft propeller was determined by the machinery layout. The speed and power predictions were made for ideal trial conditions (calm water, clean hull and propellers). The speed and power prediction show that 28.3 knots can be achieved at T=6.05 m with a required propeller power of 16,913 kW and 12,722 kW on the front and aft propeller, respectively, in total a required propeller power of 29,635 kW. Compared to a similar speed and power prediction for the existing ferry at T=6.05 m and 28.3 knots, the predicted results for the optimised hull form show a propeller power saving of 17.5%.



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Figure 16 Speed and power curves.

8.5 Environmental impact In the most promising of the optimized hull forms, the wave making was slightly reduced as compared to the original hull form, especially wave making around the forward shoulder was reduced. Using the optimized hull form as input, a speed and power prediction was made for ideal trial conditions (calm weather, clean hull and propellers), resulting in a total propeller power saving of 17.5% corresponding to a saving of 6281 kW. Based on the emission calculations mentioned above, the following reductions are gained:

Isolated emission reductions

Measure CO2 NOx SOx PM

Hull form optimisation 17.5% 17.5% 17.5% 17.5%

Table 10 Emission reduction list of different measures

0

5000

10000

15000

20000

25000

30000

35000

40000

19 20 21 22 23 24 25 26 27 28 29 30

Pro

pe

ller

Po

wer

[kW

]

Speed [kn]

Existing Ferry T=6.05

New Ferry T=6.05



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9. Weight optimisation group Weight is an important design parameter in Ro-Pax ferry designs due to its effect on stability in terms of vertical centre of gravity and payload limits. Therefore, the ‘Weight optimisation group’ did not expect to identify huge weight savings when evaluating the possible savings on the optimised ferry design as compared to the existing ferry design, /1/. But the group did, however, identify three measures for saving weight and/or reducing the vessel's vertical centre of gravity. Participants in group: OSK-ShipTech A/S Lloyd's Register EMEA ROCKWOOL A/S

9.1 Methodology The weight optimisation group decided to focus on a number of different possibilities for reducing the overall weight. In the following, both methods and results of the different possibilities are presented. For applied rules and and analysis tool, see /2/ and /3/.

9.1.1 Moveable decks’ weight and space requirements Can moveable decks’ weight and space requirements be reduced? If the car deck weight is reduced by using electrical winch instead of being hydraulically operated, the weight can be reduced to 100 kg/m² (existing Vessel 130 kg/m²). It will be more efficient to redesign the car deck in such way as to be more flexible and reduce the weight. Instead of having one car deck on each side with 4 lanes, it is preferable to divide it into two parts with 2 lanes on each panel. The car deck height can be reduced to 300-320 mm if the above mentioned alternative solutions are chosen, and the panels’ steel structures are built up with u profiles so as to reduce the deck height. Implications Extra cost due to double hoisting system. The hoisting system size will, however, be reduced, and by this means the cost will not be doubled but approx. 50% higher. The benefit will be that the owner will get a vessel with a more flexible car deck, and likewise the panels’ weight can be reduced. All design parameters have to be provided to the designer to optimise the structure:

� Maximum UDL � Vehicle load incl. axle load, distance between axles � Needed free height in loaded position and in stowed position



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The total weight will be reduced by approx. 30 kg/m², and the vessel will have an efficient, economic and safe car deck with flexibility and an environmentally better solution:

� Lightweight car deck � Cable wiring is easier and cheaper � Energy saving as no continuous running is needed � No change in operation time in cold condition � No pump unit needed � Maintenance friendly

9.1.2 Deck girder and transverse heights Can deck girder and transverse heights be reduced by changing ventilation ducts? In order to answer this, the worst actual axle loads are examined. From a structural aspect, the reduction will be as follows:

� Transverse below deck 3 can be reduced by 50 mm � Transverse below deck 5 can be reduced by 40 mm � Transverse below deck 7 can be reduced by 40 mm

Simple beam calculations have been performed to check that the stress level is still in compliance with Lloyd’s Register’s requirement after the reduction of the web depth. The car deck panel depth is actually 350 mm which can be reduced to 300-320 mm. Implications The solution is both economically and environmentally feasible, and according to existing blocks weight calculation and the transverse height reduction mentioned above, the light weight centre of gravity can be reduced by 4 cm.

9.1.3 Steel superstructures Which possibilities are there for replacing steel superstructures with GRP or aluminium? A: The possibilities for using alternative materials are being compared to the reference vessel for decks 8, 9 and 10 and the bulkheads from above deck 7. By changing the structure from steel to aluminium or to composite, a weight saving potential of approx. 45% was calculated, from 480 tons to approx. 270 tons. The weight savings by using aluminium or GRP is estimated to be at the same level due to the higher requirement for insulation in case of GRP. Compared to a traditional steel construction, the change might create a more complicated working process. Especially for GRP material, the experience is as yet limited as well as the number of suppliers, working experience and certificated solutions. Based on the analysis, it should be possible to obtain a significant weight reduction, and it is recommended to change the structure of the upper part of the ship from steel to the well-known solution with aluminium.



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Implications Changing from steel constructions might increase the material cost which, of course, will influence the project in a negative way. On the other hand, the possible weight savings should improve the overall economy as well as the environmental impact of the vessel.

9.1.4 Vehicle decks Can weight of vehicle decks be reduced by optimising the spacing of longitudinals? The attained weight relative to the frame spacing for deck 3 and deck 5, respectively, is as shown in the following graphs:

Figure 17 Required steel weight for different wheel loads The general spacings of longitudinals in Ro-Pax vessels are in the range of 600 to 750 mm. One or two additional longitudinals can reasonably be arranged within the standard frame spacing with the only implication being the additional welding of the intermediate longitudinals. Hence, it should be possible to implement these at an insignificant additional cost. In case the frame spacing on the vehicle decks is chosen not to be a fraction of the vessel's general spacing of longitudinal, then connections at transverse bulkheads become more complex, but the affected area is still limited, and no significant cost increase is therefore anticipated.



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Thereby, the preferable vehicle deck frame spacing should be a fraction of the vessel's general longitudinal spacing, but if a significant weight saving can be obtained, alternative frame spacings are possible. Implications It is seen from the summary graphs that the weight per area is relatively constant from 325 to 575 mm spacing on deck 3 and from 275 to 500 mm spacing on deck 5. It is therefore concluded that no considerable weight savings can be obtained by optimizing the vehicle deck frame spacing more than the already well-known measure of applying intermediate longitudinals in the wheel loaded areas. It is further noted from the summary graphs that the different vehicles require quite different steel weights for the vehicle deck. Henceforth, it is worth considering restricting access for certain vehicles on deck 5 or on both decks to obtain a general weight saving on the vehicle decks. This should, of course, be carefully balanced with the transportation clients' needs for a flexible loading arrangement.

9.1.5 Hull steel weight Can hull steel weight be reduced by optimising the effective height of the hull girder? It has been considered that the main particulars for the chosen existing Ro-Pax ferry provide a length of the vessel of about 190 m and a height from the keel to the uppermost continuous deck of about 30 m. Hence, the length/height ratio of the hull girder is about six. As a rule of thumb, the optimum length/height ratio of a steel girder is in the range of 15 to 20. This figure is based on end supported steel girders; however, this is of course not the reality for the hull girder. The considerable difference, though, indicates to the weight group a weight saving potential worth investigating. The length of the vessel is generally fixed by the desired speed and cargo capacity, and an increase in length/height ratio is hence to be obtained by reducing the height of the hull girder. Small reductions in the hull girder height can be obtained by optimising deck girders, ceiling panels and moveable decks, however for a significant reduction, other measures are needed. The deck layout of the vessel can be changed to reduce the number of decks and thereby the hull girder height, but a number of implications are apparent. Instead, it is chosen to render the upper decks ineffective in longitudinal strength aspect by assuming a number of flexible partitions along the decks. The effect of rendering the decks ineffective is investigated by Lloyd's Registers Midship Section analysis tool RulesCalc. First a Midship section analysis for the existing ship is carried out. Then the uppermost deck is rendered ineffective. The uppermost deck's scantlings are reduced to the minimum allowable, and remaining scantlings are adjusted to obtain the required section modulus of the hull girder. The result is compared to the Midship section analysis for the existing ship. The process is subsequently repeated, step by step, rendering more upper decks ineffective. The following four Midship Sections have been investigated:



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Longitudinal effectiveness Concept 1* Concept 2 Concept 3 Concept 4 Deck 10 Yes No No No Side (26326 to 29250 m) Yes Yes No No Deck 9 Yes Yes No No Side (23500 to 26325 m) Yes Yes Yes No Deck 8 Yes Yes Yes No Side (20500 to 23500 m) Yes Yes Yes No

Table 11 Midship sections (* Concept 1 - Full Effective Midship Section)

The obtained change in steel weight for the hull girder cross section (i.e. longitudinal elements) is as shown in the following table:

ID Midship Concept Unit Weight [kg/m] Difference [%] 1 Concept 1 24366 0.0 2 Concept 2 24600 1.0 3 Concept 3 24718 1.4 4 Concept 4 25015 2.7

Table 12 Steel weights for the different concepts As seen, the steel weight will be slightly increased while the upper decks are rendered longitudinally ineffective.

Implications In order to be confident that the introduced flexible partitions will actually prevent longitudinal hull girder stresses, it will probably be necessary to include investigations of this within the hull girder. Finite element analysis is normally required by the vessel's Classification Society. It is estimated that this extended scope of the FE analysis will increase its cost by about EUR 60,000. Introducing flexible partitions within a steel superstructure will require careful design of these. The cost of this is, however, not considered as it will not be feasible to do this. The true potential of this investigation, however, is that the weight is only slightly increased while the upper decks are rendered longitudinally ineffective. This provides the possibility to replace the upper steel superstructure with lightweight materials as these lightweight materials typically are not well suited for being part of the vessel's longitudinal strength. According to this investigation, though, it is possible to gain a significant weight reduction of the upper superstructure by utilizing lightweight materials while at the same time only needing a minor weight increase of the remaining hull girder. Other investigation areas Further, it was investigated whether it was possible to neglect corrosion of vehicle decks by applying superior coating, if the weight of interior wall panels could be reduced, if interior ceilings’ weight and space requirement could be reduced, and if recent technology developments generally reduced the weight of fire insulation. These topics did not hold any relevant possibilities, and therefore they are not presented above.



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9.2 Environmental impact It has been found that the height of the transverse beams on decks 3, 5 and 7 can be reduced by 40-50 mm. By using two 2-lane decks instead of a single 4-lane deck, the car deck panel depth can be reduced by 30-50 mm. Weight savings can be achieved on the car deck by using electrical instead of hydraulic hoists. The savings in weight are negligible; the real results are the lowering of the centre of gravity by 4 cm which are very interesting from a stability point of view. Additionally, superstructures of decks 8 to 10 can be constructed in aluminium to reduce their weight. This, however, renders them longitudinally ineffective. The longitudinal strength must thus be ensured by increasing the longitudinal structures in the remaining hull of an overall 2.7% by weight. The increase in steel weight for the remaining hull is, however, worth the reduction in weight that is achievable from deck 8 to 10.

Table 13 Weight optimization results Environmentally, the reduction of weight can be transformed into a saving of fuel and emissions. Change in displacement of 214 ton or 209 m3 together with a water plane area of 3,499 m2 results in an estimated change in draught of 0.06 m. The displacement and draught changes are relatively small, so it is assumed that the admiralty coefficient can be used to estimate the change in power and consequently the change in fuel consumption and emissions. For T=6.05 m the displacement for the optimized hull in chapter 8 is 15887 m3, and the propulsive power is 29,635 kW at 28.3 kn. With a displacement of 15678 m3 for the lighter vessel, the admiralty calculation gives a reduced power of 29375 kW which means a reduction in power of 0.9% and consequently a saving of fuel and emissions of 0.9%. Based on the emission calculations mentioned above the following reductions are gained:



Hull form optimisation 0.9% 0.9% 0.9% 0.9%


Area of investigation Weight reduction [ton] Weight reduction [%] Moveable car deck 89 0.76 Transverse girder reduction ~0 ~0 Superstructure in aluminium and hull girder increase 125 1.06

Total 214 1.82



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10. Machinery and fuel selection The fuel and propulsion group has been focused on finding the most suitable fuel and propulsion system for the operation profile of the Ro-Pax ferry from Sweden mainland to Visby, Gotland. With a starting point from an existing Ro-Pax ferry with a known operation profile and from the many possible machinery and fuel selection measures, the machinery and fuel selection group participants decided to investigate the following topics:

1. Optimum fuel based on availability, price, emissions and innovation (please see section 6.2).

2. Optimum machinery configuration 3. Optimum selection of propulsion units 4. Waste Heat Recovery 5. Variable Speed Drives 6. Other fuel saving technologies

The findings of these topics are presented below. Participants in group: ABB Danfoss Desmi DNV Johnson Controls Maskinmesterskolen i Aarhus Novenco OSK-ShipTech SPX (APV)

10.1 Method and calculations The selected topics have been assessed as described in the following chapters.

10.1.1 Route, operation and speed profile Please see section 5 earlier in the report.

10.1.2 Safe Return to Port The vessel is applicable under the Safe Return to Port (SRtP) requirements laid out in SOLAS Reg. II-2/21, Reg. II-2/22 and Reg. II-1/8.1. for passenger ships constructed on or after 2010-07-01, having a length of 120 m or more or having three or more main vertical zones.



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When fire damage does not exceed the casualty threshold indicated in paragraph 3, the ship shall be capable of returning to port while providing a safe area as defined in regulation 3. To be deemed capable of returning to port, the following systems shall remain operational in the remaining part of the ship not affected by fire:

1. Propulsion; 2. Steering systems and steering-control systems; 3. Navigational systems; 4. Systems for fill, transfer and service of fuel oil; 5. Internal communication between the bridge, engineering spaces, safety centre, fire-

fighting and damage control teams, and as required for passenger and crew notification and mustering;

6. External communication; 7. Fire main system; 8. Fixed fire-extinguishing systems; 9. Fire and smoke detection system; 10. Bilge and ballast system; 11. Power-operated watertight and semi-watertight doors; 12. Systems intended to support "safe areas" as indicated in paragraph 5.1.2; 13. Flooding detection systems; and 14. Other systems determined by the Administration to be vital to damage control efforts.

This means that the propulsion and the 13 other systems specified above must function in 6 knots at BF 8 and be able to return to port with the following fire or flooding scenarios:

1. Fire. Loss of space of origin up to the nearest "A" class boundaries, which may be a part of the space of origin, if the space of origin is protected by a fixed fire extinguishing system; or

2. Fire. Loss of the space of origin and adjacent spaces up to the nearest "A" class boundaries, which are not part of the space of origin.

3. Flooding. Loss of any single watertight compartment. The SRtP requirements will be part of the design process and limit the number and configuration of different machinery alternatives.

10.2 Fuel alternatives, benefits and disadvantages

The possible alternatives for fuel selection are:

1. Heavy Fuel Oil (HFO) with scrubber 2. Marine Gas Oil (MGO) 3. Liquefied Natural Gas (LNG) 4. Methanol 5. DME

At the moment, there is a 1.0% sulphur limit for all operation in the Baltic Sea. This limit will be further decreased in 2015 to 0.1%. This eliminates the use of low sulphur without abatement such as low sulphur HFO (LSHFO). If the vessel is constructed after 2016-01-01, NOx Tier III



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requirements will not apply. LNG or methanol as fuel or NOx abatement technology will need to be deployed in order to fulfil these requirements.

10.2.1 HFO with scrubber

Benefits Disadvantages Cheap Needs SOx abatement Readily available Price dependent on oil price Low investment costs Innovation level is low Space efficient compared to LNG and MeOH (methanol)

Could need SCR or NOx abatement

Known technology Changing quality, additives and impurities Salinity level in Baltic may challenge the use

of wet scrubber (w/sea water) Maintenance cost and cost of consumables

Table 15 Benefits/Disadvantages – HFO with scrubber HFO will still be one of the most important fuels in the years to come, but with SOx abatement technology installed in ECAs. Scrubber is possible to refit at a later stage if space is set aside for this purpose. Adoption of scrubbers can particularly be expected for the global fleet of vessels operating only a limited amount of time in ECA zones once the global sulphur cap of 0.5% will come into force, hence by 2020 or alternatively not before 2025. Scrubber consumable like e.g. NaOH will also have a negative impact on the operating cost.

10.2.2 Marine Gas Oil (MGO)

Benefits Disadvantages Readily available High price Low investment costs Price dependent on oil price Space efficient Innovation level is low Known technology Could need SCR or NOx abatement

Table 16 Benefits/Disadvantages – MGO MGO will for many vessels be an easy alternative, especially for older vessels currently under operation where it is not financially sound to invest in scrubbers or LNG or methanol tanks and engine technology. However, distillate fuel will be a very price sensitive alternative. MGO has not been chosen as a future fuel due to the potentially high fuel costs associated.



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10.2.3 Liquefied Natural Gas (LNG)

Benefits Disadvantages Potentially cheaper than oil Infrastructure - Only available in Nynäshamn

(presently) Tier III compliant fuel High space requirements (around 3-4x) Known technology High investment costs No scrubber needed Price uncertainty Lower emissions of SOx, NOx, PM and CO2 than MGO/HFO

Training and crew familiarisation

Lower maintenance cost Cleaner engine room / less noise Reduced lube oil consumption

Table 17 Benefits/Disadvantages – LNG LNG is known technology on board ships today. Not only does LNG solve the immediate emission regulations, but there is a trend towards cheaper LNG and more expensive oil on a global scale which makes LNG an interesting alternative as future fuel for shipping. Natural gas is still not easily available in most ports, but an LNG terminal has been built in Nynäshamn offering bunkering. If the extra cost could be defended, LNG will be a viable option for the new Ro-Pax design. For using LNG as fuel, machinery, equipment and tanks could be refitted, but this will require that there is space for the tanks. This solution is, however, not suitable as the investment costs would most likely be too high. Hence adoption with newbuilding design will be beneficial and much more cost efficient. Dual fuel engines running on LNG will need approx. 1-2% pilot fuel. This percentage is dependent on the load of the engines. This could be HFO or MGO.

Figure 18 LNG terminal under construction in Nynäshamn (May 2010, Linde Group)



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10.2.4 Methanol

Benefits Disadvantages Cheaper than MGO High space requirements (around 3-4x) Price not dependent on oil price Unknown technology for marine application Results indicate Tier III compliance achievable More costly fuel than HFO and LNG Readily available industrial product No infrastructure for marine application No scrubber needed Low flash point (12 degrees C) Medium investment costs Easy storage at ambient temperature and pressure versus LNG

Methanol can be produced in a “green” way Table 18 Benefits/Disadvantages – Methanol Methanol as a marine fuel is still in a test phase with some small scale tests done on board ships and test bed. Results show that dual-fuel engines could run on methanol with some modifications. Methanol is typically produced from natural gas which makes it less energy dense than LNG, and it is likely to be more expensive than LNG on a global scale. However, methanol production at a local site with access to a natural gas source will possibly have different competitiveness. As opposed to LNG, methanol can also be produced in a “green” process by gasification of organic feedstock. If crops would be used for the purpose of producing marine fuel, this would naturally raise an ethical debate. However, one of the advantages of employing methanol as a sustainable source of fuel is the diverse array of feedstock from which it can be produced. Besides industrial production from natural gas and coal, methanol can be made from anything organic. Timber waste, landfill gas, trash, pulp mill black liquor, and agricultural waste can be converted into methanol as a way to store and distribute the energy from each source. For this particular project with origin in Sweden, black liquor waste from the pulp mills makes it very interesting as a sustainable solution which could be adopted locally. Since decomposition of black liquor is required, methanol production could potentially also see political and financial goodwill in the local case. Raw methanol includes approximately 10% more water than chemical methanol which is the product applied by industry today. The process of producing raw methanol should be both simpler and consume less energy. Marine engines are suitable for burning raw methanol, and a benefit is that reduced Nox emissions could be expected. Hence raw methanol could potentially be worth investigating for further marine applications. Since storage is also much simpler and less expensive than e.g. for LNG, methanol has been chosen for further studies due to quite easy refit of needed equipment and storage, compatibility to ECA (SOx and NOx) and a relatively low price. Methanol as fuel could be refitted, but will require medium investments. Tanks will need to be provided with cofferdams, and piping will need to be double walled. Engines will need to be modified for methanol.



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10.2.5 Dimethyl Ether (DME)

Benefits Disadvantages

Cheaper than MGO High space requirements (around 3-4x) Price not dependent on oil price Unknown technology Results indicate Tier III compliance Achievable

More costly fuel than HFO and LNG

No scrubber needed Medium to high investment costs Pressurised main fuel tank is not needed Some energy is lost in methanol-DME OBATE Methanol-DME converter necessary – Higher

CAPEX Low flash point (-41 degrees C) Pressurised service tanks required

Table 19 Benefits/Disadvantages – DME DME is made from methanol and could be used in dual-fuel engines with small modifications. Methanol could be carried in ship tanks and converted to DME before entering a pressurized service tank. As DME is made from methanol, and methanol is typically made from natural gas, DME will always be more expensive than both methanol and LNG. A solution for an onboard conversion of Methanol to DME is available from Haldor Topsø as OBATE (On Board Alcohol-to-Ether). However, this is a costly add on feature. Considering these facts, it was concluded that adoption of pure methanol as fuel before DME will be more beneficial for the total application. DME as fuel could be refitted, but will require medium to high investments. Tanks will need to be provided with cofferdams, a DME conversion plant needs to be installed, and piping will need to be double walled. Engines will need to be modified for DME, but this conversion is regarded as minor.

10.2.6 Optimum fuel based on availability, price and emissions

Please see section 6.2.

10.3 Fuel storage and treatment requirements

10.3.1 Heavy fuel Oil (HFO) HFO is to be stored in normal fuel tanks with normal fuel treatment system.

10.3.2 Liquefied Natural Gas (LNG) LNG as fuel is to be stored in approved tanks according to DNV Ship Rules Part 5 Chapter 5 Liquefied Gas Carriers. The fuel treatment, ventilation and gas piping system are regulated by DNV Ship Rules Part 6 Chapter 13 Gas Fuelled Ship Installations. The rules provide technical requirements on how gas can be used as a fuel. The rules cover design requirements for LNG fuel tanks, and how and where tanks can be arranged and located in the ship, how engine rooms must be arranged to avoid that flammable natural gas can be ignited, how bunkering stations shall be arranged, how gas piping going through the ship has to be arranged and so on. They also provide detailed design requirements for piping and components, requirements for gas detection systems, shut down systems, and other necessary safety boundaries.



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The main features are special gas fuel tanks, ventilation requirements, double walled piping and dangerous gas zones. The applicable tank volume for this vessel is 500 m3. This is based on enough fuel for 3 days of operation at average consumption.

10.3.3 Methanol Methanol is to be stored in tanks built according to DNV Ship Rules Part 5 Chapter 7 Section 8 Offshore service vessels for transportation of low flashpoint liquids. The fuel treatment, ventilation and gas piping system are regulated by DNV Ship Rules Part 6 Chapter 13 Gas Fuelled Ship Installations. The main features are fuel tanks made of stainless steel with cofferdams, ventilation requirements, double walled piping and dangerous gas zones. New rules from DNV for Methanol fuelled installations were made available July 2013.

Figure 19 Sketch of methanol tank configuration



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10.4 Machinery selection To find the optimum machinery configuration for the vessel, the total fuel consumption has been the designing parameter for the machinery configuration selection. A number of different machinery configurations have been assessed based on fuel consumption and the propulsion and electric power requirements laid out in chapter 10.1.1.

Alt no

Alt name ME Gear FPP CPP AE PTO

1 Diesel Mechanical 4 2 2 2 2

2 Diesel Electric Azipod 4 2 (1)

3 Diesel Electric Azipod CRP 4 2 (1)

4 Diesel Mechanical Azipod CRP 4 1 1 1 (1)

5 Diesel Electric Azipod 6 2

6 Diesel Electric Azipod CRP 6 2

7 Diesel Electric 4 2 (1)

8 Diesel Electric 6 2

9 Diesel Electric Double Azipod CRP 4 4

Table 20 Initial machinery configuration alternatives Selection criteria:

� Fuel consumption and emissions � CAPEX � Maintainability and redundancy

Alt no Fuel consumption

and emissions CAPEX Maintainability and

redundancy 1 ++ +++ ++

2 ++ ++ +++

3 +++ ++ +++

4 +++ ++ ++

5 ++ + +++

6 ++ + +++

7 + ++ ++

8 + ++ +++

9 ++ + ++

Table 21 Pros and cons of different machinery alternatives (+ indicates more benefit)



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The following alternatives were discarded due to:

4. Maintenance issues (should have the possibility to maintain one engine while in transit with slightly reduced speed) and not having the flexibility of a DE system.

5. Higher fuel oil consumption and higher CAPEX of 6 engines than the solution with 4 engines.

6. Higher fuel oil consumption and higher CAPEX of 6 engines than the solution with 4 engines.

7. Higher fuel oil consumption than alternative 1 and 2. 8. Higher fuel oil consumption and CAPEX than the solution with 4 engines. 9. Lower efficiency and higher CAPEX than alternative 3.

The group went forward with machinery configurations 1, 2 and 3. This is due to the reasons mentioned above. The dual-fuel (DF) engines have been selected at this stage to be able to compare LNG, methanol and diesel operation. More detailed calculations will follow in the later design steps. The machinery configuration should be optimised for the given operational profile and is not suitable to be altered after delivery of vessel.



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Alternative 1 DM

4 x Wärtsilä 12V50DF 3 x Wärtsilä 6V34DF 2 x reduction gears 2 x CP propellers 2 x rudders 2 x 2 MW Bow thrusters Total installed power: 54.9 MW

Alternative 2 DE Azipod

4 x Wärtsilä 12V50DF 2 x 17.5 MW Azipods 2 x FP propellers 2 x 2 MW Bow thrusters Total installed power: 46.8 MW

Alternative 3 DE Azipod CRP

4 x Wärtsilä 12V50DF with generators 1 x ABB Azipod XO2100 15 MW 1 x FP propeller 1 x Electro motor 20MW 1 x FP propeller 2 x Auxiliary rudders 2 x 2 MW Bow thrusters Total installed power: 46.8 MW

Table 22 Machinery configuration alternatives



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Concept Diesel Mechanical Diesel Electric

Azipod Diesel Electric Azipod - CRP

Azipod type - 2 x XO2100 1 x XO2100

Propulsion power 2 x 19MW 2 x 17,5 MW 15 MW + 20 MW

Efficiency ++ ++ +++

Layout flexibility ++ +++ ++

Manoeuvrability + +++ ++

Redundancy ++ +++ +++

Ship price +++ ++ ++

Life cycle cost + ++ +++

Table 23 Pros and cons of different machinery alternatives (+ indicates more benefit) From this qualitative analysis of the machinery alternatives, the best option is the CRP solution. The financial, quantitative analysis shows that alternative 1 and 2 consume more than 10% and 6% additional fuel compared to alternative 3.

Figure 20 Machinery alternative 3 - DE Azipod CRP



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10.5 Machinery alternative 3 – DE Azipod CRP Alternative 3 consists of:

� 4 x Wärtsilä 12V50DF with generators � 1 x ABB Azipod XO2100 15 MW � 1 x FP propeller � 1 x Electro motor 20MW � 1 x FP propeller � 2 x Auxiliary rudders � 2 x 2 MW Bow thrusters

The new GSF hull design has been subjected to CFD hydrodynamic optimisation and wake field optimisation to fit the CRP solution. FORCE Technology has performed the CFD calculation and used open water data input from ABB on the CRP propellers. The transit speed of 28.5 kn for MF Visby has been challenged slightly due to expected increased manoeuvrability with the powerful steering thruster. A limited time saving potential during manoeuvring in port operations has indicated some minutes’ (app.4 min) saving which results in a slight top speed reduction in transit of around 0.2 kn. Hence, with this in mind, the GSF optimisation was done at a target transit speed of 28.3 kn. Furthermore, hull optimisation has been based on an assessment of the loading and hence the operational draught profile seen over a year of typical loading conditions of the vessel. This identified a draught of 6.05 m to be the most applicable design point rather than optimising the hull resistance at full design draught 6.40 m. The vessel typically spends around 40% of the loaded time around 6.05 m and is almost never loaded to 6.4 m! Accordingly, the optimised hull and CRP has proven the following propeller power requirement.

Figure 21 Propeller power requirement comparison vs. speed

0

5000

10000

15000

20000

25000

30000

35000

40000

19 20 21 22 23 24 25 26 27 28 29 30

Pro

pe

ller

Po

wer

[kW

]

Speed [kn]

Existing Ferry T=6.05

New Ferry T=6.05



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Speed [kn] Existing ship Total propeller power [kW]

GSF new total propeller power [kW]

Difference [%]

28.3 35916 29635 -17,5 28.5 36890 30590 -17,1

Table 24 Propeller power requirement comparison The power split on the CRP has for the project been concluded as 16.9 MW front and 12.7 MW aft (at 28.3 kn). Including a sea margin of 15%, the 20 + 15 MW propulsion units layout provide sufficient operational margin. For direct comparison of the actual engine power rating, mechanical losses of the existing design and all electrical losses for the gas electrical configuration and electrical drive units etc. have been included, altogether resulting in an engine power requirement as indicated in the table below.

Speed [kn] Existing ship Total Engine power [kW]

GSF new total Engine power [kW]

Engine power saving incl. losses [kW]

Difference [%] Fuel saving potential

28.3 37325 32184 5141 -13.8% 28.5 38337 33221 5116 -13.3%

Table 25 Engine power requirement including mechanical and electrical losses In fact, fuel saving potential could be justified as engine power consumption comparison between the existing design at transit speed 28.5 kn versus the new GSF design at 28.3 kn due to the improvement potential in port manoeuvring time. This would result in a power saving of 6153 kW, i.e. 16%. However, for clean comparison it was decided to apply the power differential at 28.3 kn for both ships. This resulted in a power and fuel saving of 5141 kW = 13.8%.



CRP propulsion and hull form 12.7 % 12.7% 12.7% 12.7%

Table 26 Emission reduction for CRP and hullform This figure is, of course, only applicable for full transit speed, hence the full operational profile and fuel consumption must be assessed resulting in an isolated fuel saving potential of 12.7% only due to optimised hull and CRP propulsion. The auxiliary rudders are needed due to the SRtP requirements. If the Azipod unit should fail, the vessel needs steering capabilities to get back to port. The small rudders will also allow light directional steering control during high speed transit. Hence fixation of the pod in centre line will optimise propulsion during transit.



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The Azipod unit was too high for the initial RoRo deck design on the vessel. The solution is to penetrate the RoRo deck to be able to fit and accommodate the height of the Azipod drive unit in way of the centre line. In order to facilitate efficient loading of the main deck, new shore logistics have been proposed by applying land based ramps to facilitate direct to shore load and offload of the upper car deck. There are also possibilities to lower the standard height of the Azipod unit. The CRP solution has the lowest fuel costs and emissions, increased manoeuvrability and lowest life cycle costs.

10.6 Power supply in harbour When the vessel is docked, there are two alternatives to using the vessels’ auxiliary engines to generate the needed power on board:

� Shore power from existing power grid (including wind/hydro power) � Dedicated harbour generator

The two alternatives will be described in the below sections

10.6.1 Shore power The vessels spend much of the time and a significant amount of fuel in port. With a shore power system, the harbour generator could be replaced, and the cost of fuel would be significantly reduced. Of the total fuel consumption, 6% is consumed in port. To be able to cover the needed power requirement, a power connection module needs to be installed in the vessel’s switchboard room and on the vessel side or aft. If the vessel grid frequency is 60 Hz, it is necessary with a 2.5 MW, 690 V frequency converter with sinus filter to convert from the 50 Hz shore power. In addition to the equipment needed on board, shore power systems in the three ports need to be installed. A 6.6 kV shore based system should be able to cover the needed electric loads for the vessel and provide a suitable and manageable cabling solution for easy connection. Accordingly, a transformer 6.6 kV to 690 V, 50 Hz will also be necessary on board. Clean shore power from wind turbines or hydro power has been proposed by the Gotlands Energy Bolag AB and would make the shore power solution even more sustainable and green. The power price used in this project is 0.07 USD/kWh. This is one third of the cost of power generated on board.



Shore power 3.6% 3.6% 3.6% 3.6%

Table 27 Emission reduction from shore power



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10.6.2 Harbour generator By installing a harbour generator, the load on the engines could be increased considerably from around 10-15% which is the case with large main engines. Getting an average load up to 50% would decrease the SFOC by around 35%. This again would lead to a reduction in the total annual fuel consumption of around 580 MT of fuel. This means that the harbour generator will be paid back in less than 3 years with today’s fuel prices.



Harbour generator 2.2% 2.2% 2.2% 2.2%

Table 28 Emission reduction from harbour generator

10.7 Waste Heat Recovery (WHR)

10.7.1 Waste heat available Based on the total fuel oil consumption, the optimum propulsion machinery has been identified as four-stroke dual fuel diesel engines operated on LNG. The main engines selected for this study are 4 x Wärtsilä 12V50DF (gas/diesel engines) running on LNG with approx. 2 percent diesel oil. To ensure sufficient propulsion power when running the ship at full speed, the engine load is calculated to 85%. (Engine output at 100% is 11.700 kW). The dual fuel four-stroke diesel engines operated in diesel electric mode will have an efficiency of about 48%, and therefore a high amount of energy is lost in the exhaust gas and engine cooling water. In order to save fuel and lower emissions, it should be determined if the use of a Waste Heat Recovery system would be possible. The waste heat could make up as much as 52% of the fuel oil consumption. The exhaust gas represents 31.8% with a temperature of 400oC (LNG mode). The remaining thermal losses will consist of 1.3% radiation loss which cannot be recovered and 18.9% low temperature loss in cooling water and lubrication oil. A large variety of waste heat recovery technologies have been available for many years, and new future systems are being discussed based on what is technically possible, economical aspects and application feasibility. The utilization of the diesel engine waste heat can be divided into the use for thermal, electrical and mechanical power.

10.7.2 Thermal power Primarily, the exhaust gas waste heat can be used for heating purposes, and the vessel is designed to be fitted with two 1,750 kW thermal fluid heaters. The thermal fluid heaters will provide heating for the accommodation, potable hot water system and the main- and auxiliary engine LNG system. Waste heat from the exhaust gas can be utilized for air condition purposes by installing an absorption refrigeration system which will supply cooling for the air condition systems. An absorption refrigeration system in combination with exhaust gas waste heat has been found both economically and technically feasible in studies involving gas turbines instead of internal combustion engines. This study will not look closer into this opportunity, but it could be an interesting technology, especially for a passenger vessel which consumes a significant amount of



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power for air conditioning of the accommodation. Due to the low temperature of the cooling water and lubricating oil, the remaining waste heat will not find much use unless an ORC system is installed.

10.7.3 Electrical power The most interesting method used to recover waste heat is the conversion from heat to electrical power. Extra electrical power can normally always be utilized to substitute power produced by the auxiliary engines. In this project, the extra power generated can also be useful for the diesel electrical propulsion system and potentially save propulsion fuel costs.

10.7.4 Combined cycles Combined cycles for electrical power production have been used for many years on board larger vessels powered by large two stroke engines. Combined cycle plants employ more than one thermodynamic cycle, normally a large two stroke diesel engine in combination with a steam turbine generator.

10.7.5 Rankine cycle (steam turbine generator) The exhaust gas from the propulsion and auxiliary engines is used to produce steam which is used to power a steam turbine generator.

Figure 22 General flow diagram of a typical steam turbine system Due to the relatively low exhaust gas temperature, the steam turbine efficiency will be low. The dimensions of the turbine and auxiliary equipment will require much space, and the complete steam turbine generator plant including boilers, condenser, feed water system and pumps will result in



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high investment costs. Earlier studies have shown that the payback time will exceed 15 years, /8/. It is estimated that the total electrical efficiency can be increased by 4% by installing a steam turbine generator system in combination with a four stroke dual fuel engine. The main problem will be to design a ferry with enough engine room space to fit large boilers which has been found difficult with the current ferry design.

10.7.6 ORC Organic Rankine Cycle (turbine generator driven by an organic fluid) The Organic Rankine Cycle (ORC) has been well known for many years but has not yet found its break through on the maritime market. The system can be compared to a Rankine Cycle (steam turbine generator) as the technical setup is similar. The main difference is the medium used for the expansion in the turbine. An organic fluid (gas, refrigerant or similar) replaces water in order to be able to evaporate the medium at lower temperatures. The lower point of evaporation makes it possible to utilize the waste heat in the lower grade cooling water and lubricating oil system.

Figure 23 ORC system from Turboden S.r.l. The turbine generator uses the hot temperature thermal oil to pre-heat and vaporize a suitable organic working fluid in the evaporator (8→3→4). The organic fluid vapour powers the turbine (4→5) which is directly coupled to the electric generator through an elastic coupling. The exhaust vapour flows through the regenerator (5→9) where it heats the organic liquid (2→8). The vapour is then condensed in the condenser (cooled by the water flow) (9→6→1). The organic fluid liquid is finally pumped (1→2) to the regenerator and then to the evaporator, thus completing the sequence of operations in the closed-loop circuit.



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Investigation into the possibility to recover exhaust gas heat in ferries has been carried out, concluding that the project is not yet interesting for several reasons:

� The engine room space needed for the whole ORC installation is exceeding what a ferry can provide.

� The available ORC equipment is produced with different norms and standards than the ones used in the maritime industry.

� The most commonly used process mediums are flammable fluids and would require special design and approval from the classification society.

The technical obstacles listed above can all be solved in future design of the ferry and the ORC system. Since we are already installing thermal fluid heaters in the engine room, we have decided to investigate the economical side of installing an ORC system. Calculations are carried out based on data available for the dual fuel main engines, (4 x 12V50DF), and a standard ORC system supplied by Turboden and fed by the thermal oil circuit. The calculations show that approximately 2.9 MWe can be produced from the waste heat from the four main engines running on 85% load. The investment cost for a complete installation (including heat recovery exchangers, thermal oil circuit, ORC system with turbine generator) is estimated to be in the range of 2,000 – 2,500,-€/kWe. Earlier studies of medium speed engines have shown that the ORC plant has 15% lower annual costs than a conventional steam turbine generator plant, and the payback time exceeds 12 years, /6/ and /8/.

Calculation of fuel savings and payback time:

� Electrical power from the ORC system: 2,900 kWe � Total power consumption at 85 %: 83,000 kW � LNG Price: 840 $/ton � Gas LHV: 49,620 kJ/kg (Wärtsila product guide) � Operation time: 4,001 hours/year (hours in transit and manoeuvring per year) � Fuel savings: 720,000 US$/year � ORC system installation price: 7,800,000 US$ � Payback time for investments: 11 years � Total engine efficiency raised by: 3.5%

10.7.7 TCS-PTG (Turbo Compound System with Power Turbine and Generator) The power turbine generator is available from MAN Diesel & Turbo in the output range of 700 kW-4.700 kW. The current design is working in combination with larger two stroke diesel engines with rated outputs above 20 MW, but it is not yet available for use with four stroke engines. It could be a both technically and economically feasible solution, and the system would require less space in the engine room than the steam turbine and ORC systems. Up to 5% of additional power can be extracted from the gas, and the payback time is estimated to 3-5 years /7/.



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Figure 24 MAN Diesel & Turbo TCS-PTG

SteamTrac/SteamDrive from Voith (Piston expander waste heat recovery system) It would be possible to use the exhaust gas waste heat to produce mechanical power which would increase the total diesel engine efficiency.

Figure 25 Voith SteamTrac/SteamDrive system, /5/. This is possible by using the waste heat as heat source for the operating medium of a piston expander which is mechanically attached to the crankshaft and/or an electric generator. Exhaust gas heat is used to produce superheated steam in the heat exchanger and forward it to the piston expander. The steam expands in the cylinders of the expander, and the produced power is either forwarded directly to the diesel engine drive system through a coupling or converted into electrical energy in a generator. The system has been found suitable for both new ship developments and for retrofits. The fuel consumption can be reduced significantly, but no data supporting this statement is currently available to the public.



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10.8 LNG charge air cooling It is possible to utilise the LNG cold to cool down the charging air in the engines. Low temperature air is denser than high temperature air and thus allows more air to enter the combustion process in the engines. Normal charge air temperature is usually around 40-50 ̊C. By cooling this down to 15-20 ̊C with the help of the cold LNG, the SFOC will be reduced by 1.5% at all engine loads. This will give a reduction of 1.5% in the total fuel consumption. The calculation steps come from ISO 3046, /4/.

Figure 26 Fuel savings due to colder charge air (ISO 3046) Heating of LNG is needed before the natural gas can be supplied to the engines. Heating is also needed in the heat exchangers used to build up pressure in the LNG tanks. Thereby large amounts of energy have to be transported away. The LNG heating/cooling circuit is the key to utilising the low LNG temperatures for additional fuel savings as this circuit will be used to transport the low temperature from the LNG to systems where this cooling is useful. A glycol water mix is used as heat carrier in the circuit, this is kept above -40 ̊C to avoid freezing. We have evaluated how the low temperature can be most useful, and concluded on scavenging air cooling and possibly also FW cooling for machinery and air conditioning. Each element in the system is equipped with a temperature controlled bypass loop in order to regulate the heat exchange of the element. All in all, the system is designed to be robust and adaptable to all operational conditions with sufficient redundancy to not depend on a single system to be able to operate. In addition to the glycol, the charge air cooling system needs one or two sea water heat exchangers to cool down the glycol in case the engines are running in diesel mode without the cold of the LNG.

1,50%

1,00%

0,50%

0,00%

0,50%

1,00%

1,50%

2,00%

10 15 20 25 30 35 40 45 50 55

Charge air temperature

Fuel savings due to colder charge air



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It should be noted that the idea of cooling the charge air and evaluating the actual efficiency gain remains to be proven in practice for various engine types and combustion principles. Hence for this project, this innovation is assessed based on a theoretical consideration.

10.9 Variable Speed Drives (VSDs) All around the world, vessels operate every day at conditions that are very different from the specifications for which they were designed. The classification society requirement for all sea going vessels is that the cooling systems are designed to be able to operate in up to 32°C sea water and at 100% load on the main engine.

10.9.1 Technical description of temperature and load controlled VSD for cooling water systems The analysed solutions below are based on technology provided by Desmi OptiSaveTM and Danfoss Power Electronics. The main goal of optimised temperature and load controlled VSD systems is to maintain adequate cooling capacity at all times. Secondary, this modern technology reduces power consumption of the ship’s installed sea water and fresh water cooling pumps. This is when the required cooling is lower than the design criteria, meaning that excess cooling is produced. This situation will occur when sea water temperature is low, and when the vessel is sailing at low speed. The temperature and load controlled VSD system is the implementation of the well-known and widely used technology of controlling electrically driven pumps with frequency converter drives. The system also includes additional functionality as well as additional controllability compared to the usage of only Variable Speed Drives (VSD). Each pump has its own individually mounted VSD for pump speed/flow regulation. The VSDs can actually calculate the motor temperature (without a sensor) in order to prevent motor overheating. This is also a useful feature for retrofitting applications. Each installed sea and fresh water cooling pump is to be connected to its own VSD. Each VSD is coupled to the Control Panel which in turn is being fed with process information from the system’s temperature and pressure transmitters.



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Figure 27 Capacity and head of different pump alternatives The intention with the optimised VSD solution is to ensure that the delivered flow always fits the required cooling capacity. The system will operate between the red pump curve (two pumps run full speed) and the blue pump curve (one pump runs half speed). Case stories have proven that the solution will optimize the cooling system by up to 80%.

10.9.2 Design data 3 LT SW pumps: 1 Harbor pump: Flow Q= 900 m3/h Flow Q= 290 m3/h Pressure H= 2.5 mLC Pressure H=2.5 mLC Power consumption = 90 kW Power consumption = 36 kW 3 LT FW pumps: 1 Harbor pump: Flow Q= 750 m3/h Flow Q= 240 m3/h Pressure H= 2.0 mLC Pressure H=1.5 mLC Power consumption = 66 kW Power consumption = 13,2 kW The optimised system consists of the following parts:

� VSD for controlling the speed of the cooling pumps � OptiSave™ Control Panel; for adding functionality and controllability to the cooling pump

and cooler system. � Operator Interface Panel; a graphic human <–> machine interface touch screen for ease

of use. � Temperature and Pressure Transmitters; for measuring process values to be used with

the OptiSave™ Control Panel. � Control valve; for measuring 3-way valve set point value. � Automatically operated valve actuators; for controlling flow through sea water coolers.

Hea

d [

mL

C ]

Capacity [ m3/h ]

One pump normal reduced speed Pipe curve

One pump min rpm Two Pumps in parellel

Two pumps half speed



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10.9.3 Savings with temperature and load controlled VSD In the following, a basic description is given of the potential cost savings that can be made on the main cooling sea and fresh water pumps. The savings can be achieved by applying temperature and load controlled VSD pumps and thereby adjusting the flow so that it matches the actual requirements. Case 1: HFO as fuel – Traditional Ro-Pax vessel

� Fresh water cooling is required � Sea water cooling is required

Case 2: HFO as fuel – With temperature and load controlled VSD

� Fresh water cooling is required � Sea water cooling is required, calculations are based on a sea water temperature of 15 ̊C

Case 3: LNG as fuel – With temperature and load controlled VSD

� Fresh water cooling is required � Sea water cooling is not required

Case 4: Methanol as fuel – With temperature and load controlled VSD

� Fresh water cooling is required � Sea water cooling is required, calculations are based on a sea water temperature of

15 ̊C Results and conclusion Based on above operation profile and a sea water temperature of 15 ̊C, the following results are obtained.

Figure 28 Total fuel expenses per year isolated for cooling with or without optimized VSDs Based on the above figure, it is concluded that the total cooling costs with LNG as fuel is the solution that creates the highest savings of 79% compared to the traditional Ro-Pax vessel.

$0

$50.000

$100.000

$150.000

$200.000

$250.000Total cooling costs

Case 1: HFO as fuelTraditional RO-PAX vessel

Case 2: HFO as fuel withDESMI OptiSave

Case 3: LNG as fuel withDESMI OptiSave

Case 4: Methanol as fuelwith DESMI OptiSave



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The investment in LNG as fuel also has the shortest payback time combined with the highest payoff after seven years in operation.

10.9.4 Technical description of VSD controlled engine room ventilation system The ventilation fans in the engine room must be dimensioned for full load on all engines and auxiliary systems as well as maximum weather temperatures. By using VSD controlled fans based on actual engine room temperature and air pressure, the power consumption can typically be reduced by 30-50%. Payback time: 1-2 years.

10.10 DC-Grid The onboard Direct Current (DC)-Grid is an innovative technology amended to the marine industry which gives new and improved performance and operational opportunities on board ships. The technology uses DC as a means of transporting power and energy to different consumers on board the vessel, thus enabling variable speed operation of the generator sets. In comparison to today’s Alternating Current (AC) distribution technology on vessels, the onboard DC-Grid provides additional advantages such as significantly reduced fuel oil consumption, emission reduction, reduced maintenance and new operational modes with a more responsive vessel system. Moreover, onboard DC-Grid will offer a more flexible vessel outline with minimized electrical equipment layout in relation to effort and utilisation of new space prospects for larger fuel or gas tanks or, if preferred, an increased workspace area. The onboard DC-Grid is not only a solution that addresses today’s ambiguous topics on board ships, but is also a technology that is prepared for connection of future solutions such as new generations of equipment, new renewable energy sources or new propulsors. System description In traditional electrical propulsion systems, variable-frequency drives typically account for more than 80 percent of the installed power. The onboard DC-Grid concept utilizes a reworked and distributed multi-drive system where distributed rectifiers, transformers and switchgears are eliminated. As seen in the figure, the system merges the various DC links around the vessel and distributes power through a single medium voltage DC link, thereby eliminating the need for main AC switchboards, distributed rectifiers and converter transformers. The elimination of the AC distribution equipment opens new possibilities when discussing vessel layout and flexibility. Further, all generated electric power is fed either directly or via a rectifier into a common DC bus that distributes the electrical energy to the onboard consumers. Each main consumer is then fed by a separate inverter unit. When an AC distribution network is still needed, for example with a 230 V hotel load, it is fed using island converters developed by ABB to feed clean power to these more sensitive circuits. Benefits - fuel savings When operating marine combustion engines at constant speed, the fuel consumption is lowest at a very small operating window, typically around 85 percent of rated load. With the introduction of variable-speed operation of the engine, this window of optimal efficiency can be extended as far down as 50 percent, depending on the engine. If the engine is operated at loads below this, the engine efficiency remains significantly higher than that of the traditional fixed speed equivalent.



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The end result is that a vessel operating with high transient load pattern like e.g. anchor handlers and tugs can achieve fuel savings of up to 20% with the onboard DC-Grid solution. For this vessel with stable operation area in transit, the potential is much less. The main effect of a DC-Grid solution in this project is during manoeuvring and port operations, hence a very limited operational window to justify the investment. Benefits - reduced maintenance and emission reduction by more efficient operation With onboard DC-Grid, the system is no longer obliged to run the generators at fixed speed. With the feasibility of running the generators at variable speed, the fuel consumption is always at its optimal point and provides the opportunity to reduce fuel consumption by up to 20%. Running generators more optimally will not only prolong the maintenance intervals, but prolong the generators’ life-span and reduce emission impact generated by fuel consumption. Benefits - increased space and flexibility Due to removal of AC distribution equipment, a significant increase of space for payload or larger tanks through lower electrical footprint and more flexible placement of electrical components is achieved.

Benefits - enables implementation of future technology The onboard DC-Grid is based on an open standard which gives shipowners and operators a more competitive solution to the AC distribution in the future by enabling new and improved operational modes and conditions. The technology is no restriction on today’s technology and problems, but it allows connection of new generating sources or different types of propulsion solutions in the future. Additional converters for energy storage in the form of batteries or super capacitors for levelling out power variations can be added to the DC-Grid in order to achieve e.g. zero emission operation, power peak shaving or power back-up. Energy storage media are today predicted as a new technology that will affect the marine industry with its advantages.

Figure 29 MVDC grid single line diagram For this project, a single line diagram as illustrated above has been proposed by ABB to facilitate a future MVDC solution. The medium voltage DC-Grid is today not a shelf solution, however ABB expects that this technology will be available for future ship designs within the next few years. So



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far experience is gained from low voltage (typically <1000 VDC) DC-Grid solutions already applied with promising results in a few ships. The largest potential for fuel savings through DC-Grid for this vessel type and operational profile is, of course, during port operations. Experience with diesel engines operating at a very low load is that on variable speed (DC-Grid), the SFOC is just below 200 gKW/h when comparing with fixed speed (about 20%). Thus based on the operational profile below, we would consider the following. Annual fuel savings mainly from port operations can be estimated as follows: 5,560,000 kW.h/year x (248 g/kW.h – 200 g/kW.h) = 267 Metric Ton/year

Figure 30 Example of SFOC curve for with and without DC-Grid



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10.11 Fuel costs and CAPEX The annual fuel cost of the vessel for the three alternatives and comparison between Heavy fuel oil (HFO), Liquefied Natural Gas (LNG) and Methanol.

Figure 31 Fuel costs comparison first year The fuel costs and the CAPEX of the vessel have been assessed for a vessel life of 20 years. Included in this cost is the CAPEX of engine plant and propulsion equipment, scrubber for HFO operation, fuel storage and distribution systems, steering equipment and thrusters. Maintenance of equipment is not included in the calculations.

Figure 32 Fuel costs and CAPEX for machinery and fuel alternatives over 20 years

0

5.000.000

10.000.000

15.000.000

20.000.000

25.000.000

30.000.000

DM DE Pod DE Pod CRP

Fuel Cost - HFO

Fuel Cost - LNG

Fuel Cost - Methanol*

0

50.000.000

100.000.000

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200.000.000

250.000.000

300.000.000

350.000.000

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DM DE Pod DE Pod CRP

Fuel costs and CAPEX 20 years HFO

Fuel costs and CAPEX 20 years LNG

Fuel costs and CAPEX 20 years Methanol



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Measure Monetary fuel savings Payback time

LNG 6.2% Less than 2 years

CRP Propulsion 12,7% Less than 2 years

Shore power 3.6% 2 years

Harbour generator 2.2% 3 years

WHR 3.5% 11 years

LNG Cooling 1.5% Less than 1 year

VSD 0.9% 1.2 years

DC-Grid 0.9% -

Table 29 Payback time list of different measures

10.12 Emissions Based on the emission calculations mentioned earlier, the following reductions are possible by choosing LNG as fuel:

LNG fuelled solution Isolated emission reductions


LNG as fuel due to higher LCV 15.2% - - -

LNG as fuel due to lower carbon content 11.7% - - -

LNG Total 25.1%* ~92% 98% 98%

CRP Propulsion + hull optimisation 12.7 % 12.7% 12.7% 12.7%

Shore power 3.6% 3.6% 3.6% 3.6%

Harbour generator 2.2% 2.2% 2.2% 2.2%

WHR 3.5% 3.5% 3.5% 3.5%

LNG Cooling 1.5% 1.5% 1.5% 1.5%

VSD 0.9% 0.9% 0.9% 0.9%

Table 30 Emission reduction list of different measures *If CO2—equivalents were used instead of CO2, some of this emission reduction will be negatively impacted by a certain methane slip in the dual fuel engines. Methane has a very high impact on the environment due to its powerful properties as a greenhouse gas. Methane is a 25 times more powerful greenhouse gas than CO2, /9/. Even small emissions will have a high impact on the CO2—equivalent emissions. The reduction in CO2—equivalents should be in the order of 10-20% depending on the methane slip of the Wärtsilä 12V50DF. The highest methane slip will occur in the low load operation ranges, i.e. the methane slip will not be very high in transit due to the high loads.



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Table 31 Relative savings - Environmental and economic effect of measures Total absolute fuel cost saving potential for the selected solutions is: 22,9%.

Methanol fuelled solution Isolated emission reductions

Measure CO2 NOX SOX PM

Methanol Tier II-III 98% 98%

DC-Grid 0.9% 0.9% 0.9% 0.9%

Table 32 Methanol and DC-Grid solution

10.13 EEDI

MEPC 62 adopted a new Chapter 4 to MARPOL Annex VI that includes a package of mandatory technical and operational energy efficiency measures for international shipping. The technical instruments include the Energy Efficiency Design Index (EEDI) aiming to improve the energy efficiency for ships through improved design and propulsion technologies. Presently Chapter 4 only applies to bulk carriers, gas carriers, tankers, containerships, general cargo ships, refrigerated cargo ships and combination carriers. However, it is expected that the EEDI framework for ro-ro passenger ships will be finalized during MEPC 65. A number of submissions for the calculation of required and attained EEDI have been forwarded to MEPC for their consideration. These proposals can basically be divided into three groups:

-100%

-90%

-80%

-70%

-60%

-50%

-40%

-30%

-20%

-10%

0%Fuel CO2 NOx SOx

Red

uct

ion

fro

m b

ase

cas

e va

lues

Relative savings - Environmental and Esonomic effect of measures

LNG

CRP Propulsion

Shore power

VSD

LNG Cooling



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MEPC 64/4/14 MEPC 65/4/4 (“fine-tuning” of MEPC 64/4/14) MEPC 64/4/9, MEPC 64/4/10, MEPC 64/4/11, MEPC 64/4/20 For this particular project, we have calculated EEDI values for the GSF design and compared it to MF Visby. EEDI values and comparison between the various submissions are shown in the table below. Green colour indicates compliance, and red colour indicates non-compliance with EEDI-requirements.

Table 33 EEDI values comparison between GSF and Visby The conclusion from the study is obviously that the GSF low emission design is in every way better EEDI-wise as compared to Visby. Even when using the most stringent submission, MEPC 64/4/(9+10+11+20), the GSF low emission study is in compliance with phase 1 and can possibly, with few modifications, also comply with phase 2.

10.14 Results and conclusion The following results are obtained:

10.14.1 LNG as fuel Results At the time the project was carried out, with the then CAPEX and OPEX for the LNG fuelled alternative, installation of LNG as fuel for engines and equipment was a favourable investment. The fuel price of LNG and oil was not unlikely to further decouple, i.e. LNG could very well become cheaper than oil. With improved LNG infrastructure and more competition for LNG bunkering, the prices were expected to remain stable or even decrease while oil prices were expected to increase. The isolated CO2 emissions from an LNG fuelled vessel are 25% lower than for an HFO fuelled vessel.

MEPC 64/4/14

MEPC 65/4/4

MEPC 4/4/(9+10+11+20)

Visby GSF Visby GSF Visby GSF EEDI reference 33 35 29 30 113 126 EEDI attained 27 19 19 14 144 105 EEDI compliance (%) Phase 0 81 54 67 46 128 84 Phase 1 81 54 70 48 135 88 Phase 2 95 64 83 57 160 105 Phase 3 116 77 95 65 183 120 Phase 0 January 1 – December 31, 2014 Phase 1 January 1 - December 31, 2019 Phase 2 January 1 - December 31, 2014 Phase 3 January 1, 2025 and onwards



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Implications The system represents extra costs due to engines, tanks and equipment. Due to the smaller size of the tanks, the vessel will need to refuel more often than a vessel running on HFO. LNG as fuel will require a gas safety zone on deck where no passengers or crew members are allowed to be present. LNG as fuel will require additional training of the engineers. LNG fuel is less available throughout the world than HFO, so it could be more difficult to change the sailing location of the vessel.

10.14.2 CRP propulsion Results With the current CAPEX for the machinery systems, the CRP system will be profitable in the two first years of operation. Hydrodynamic hull optimisation and wake field optimised to fit the CRP propulsion solution have proven a very promising fuel saving potential of 13.8% in full transit speed and 12.7% for the full operational profile. CRP propulsion will increase the manoeuvrability of the vessel and lead to reduced time in the manoeuvring phase and hence have an impact on the marginal top speed reduction in transit. The power split on the CRP propellers proved to have room for variation and flexibility in combination without compromising efficiency. For instance, a smaller unit aft could be investigated to provide a smaller drive unit under the main deck. Implications There will be an extra cost of the system compared to a direct driven shaft solution. It has not been possible to accommodate the size of a CRP thruster drive unit below the main deck, and hence we have chosen to propose an alternative ramp arrangement in order to allow penetration of the main deck in the CL area above the thruster. The auxiliary rudders installed to fulfil the SRtP requirements could be a hindrance and create more drag than necessary. It is somewhat unclear whether these rudders will provide the necessary steering capabilities at low speed. They are, however, an emergency solution only. The CRP solution will require additional navigation training of the officers.



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10.14.3 Shore power Results A shore power connection is an alternative to the harbour generator. The 6.6 kV, 50 Hz shore power at each port is converted to 690 V 60 Hz using a transformer 6.6 kV to 690 V and a 2.5 MVA 690 V static frequency converter system on board the vessel. The harbour generator can be eliminated if a shore power connection is established. Implications The attractiveness of the shore power connection depends on the cost per kWh of the shore power compared to the cost per kWh of the power from a harbour generator. It is assumed that the infrastructures in the 3 ports allow a shore power connection.

10.14.4 Harbour generator Results A harbour generator should be fitted in one of the engine rooms. It will save 2% per year and have a payback time of less than 3 years. In addition, the vessel will reduce the running hours on the large engines which will have a positive effect on the maintenance costs. Implications Space in the engine room needs to be set aside for this purpose. An engine with a different bore is introduced which makes more spares necessary.

10.14.5 Waste Heat Recovery (WHR) Results A WHR system will save around 3.5% fuel with a payback time of 11 years. The relatively long payback time does not place this on the prioritised list of possible upgrades. Implications WHR systems are not practicable to refit. This would require much off hire and significant CAPEX involved. WHR systems take much space in the engine room and casing area which could limit the cargo space.

10.14.6 LNG cooling Results Cooling of the charge air could potentially reduce the SFOC of the engines. If the average drop in charge temperature is 25 ̊C, i.e. from 40 ̊C to 15 ̊C, the reduction in SFOC is 1.5%. This will on average lead to an isolated reduction in costs and emissions of 1.5%. Implications It remains to be practically proven how this applies in practice for e.g. DF engines and various fuel types.



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10.14.7 Variable speed drives (VSDs) Results VSDs are typically saving energy by adjusting the liquid flow from pumps and the airflow from fans to match the requirements.

� SW cooling pumps: Are already speed controlled on existing vessel. It is no additional energy saving, and the SW cooling pumps will not be used with LNG operation when the engines are cooled by LNG.

� FW cooling pumps: Estimated 30-50% energy savings using VSDs. Payback time: 1-2 Years

� Engine room ventilation: Estimated 30-50% energy savings using VSDs based on engine room pressure. Payback time: 1-2 Years.

� Other potential VSD applications: Engine lubrication pumps, Water supply pumps, waste water pumps.

Implications VSDs reduce the electric power consumption but contribute to the harmonics distortion of the ship’s grid. Harmonic distortion filters must be installed if the total harmonic voltage distortion (THvD) exceeds class rules.

10.14.8 DC-Grid Results The fuel savings arising from the DC-Grid are mainly coming from port operations. The system’s main feature is the transport of electricity in DC which in turn eliminates the problems associated with the AC frequency. Although the generators produce electricity in AC, there is no need to maintain a fixed frequency, and therefore the generators can run at variable speed. This allows the system to optimize the Specific Fuel Oil Consumption by selecting the most appropriate engine speed taking into consideration the power demand. This feature can lead to considerable fuel savings when the engines are operating in low load. Taking into consideration the operational profile of this vessel, there is potential for significant fuel savings during port operations where the engine load is particularly low. Implications The DC-Grid is a new concept, and its use for medium voltage systems (>10 MW) is still at the conceptual level. Therefore, it is not yet possible to ascertain the price difference between the DC-Grid and a conventional AC system. The system has an inherent “plug-in” capability of different sources of energy, namely renewables like solar, batteries and fuel cells. Because the electricity is transported on DC, the harmonic voltage distortions originated by the consumers are not transmitted into the grid through the main DC bus.



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Considering the vessel’s operational profile, the overall fuel savings provided by the DC-Grid do not justify a large investment differential should that be the case when comparing to a conventional AC system.

10.15 Environmental and economic impact Due to incompatibility between some energy efficiency measures, it was chosen to go forward with the best business cases. WHR was not chosen due to a too long payback time, and harbour generator was not chosen due to a better business case for shore power.

LNG fuelled solution Isolated emission reductions Monetary fuel savings

Payback time

Measure CO2 NOx SOx

LNG Total 25.1% ~92% 98% 6.2% <2 years

CRP Propulsion/hull form 12.7% 12.7% 12.7% 12.7% <2 years

Shore power 3.6% 3.6% 3.6% 3.6% 2 years

LNG Cooling 1.5% 1.5% 1.5% 1,5% <1 year

VSD 0.9% 0.9% 0.9% 0,9% 1.2 years

Table 34 Environmental impact The total savings are as follows for the chosen alternatives:

Figure 33 Relative savings Total absolute fuel cost saving potential for the selected solutions is: 22.9%.

-100%

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11. HVAC optimisation The objective of the HVAC group was to design a system which provides optimized energy consumption for the specific operation area of the ferry. Participants in group: ABB Danfoss Desmi Johnson Controls Maskinmesterskolen i Aarhus Novenco OSK-ShipTech RockWool SPX (APV) The HVAC group has used well-known methods to document that it is rather easy to find energy savings when evaluating the possibilities through a new HVAC system against the existing system. However, a system on an operating vessel is rarely used without manual adaption, meaning that the crew on board the existing vessel turn off systems to save energy, e.g. at night when the systems are not in use and so on. Therefore, the group focused on documenting the saving potential by selecting the correct system design and the correct product design.

We have based our calculations on actual weather conditions for this vessel and used temperatures as per the two below figures:

Figure 34 Temperature distribution - Gotland



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Figure 35 Temperature distribution - Nynashamn (Stockholm) These temperatures provide the basis for calculating the energy consumption for the HVAC system on board the vessel. The temperatures from these locations give us the following temperature profile:

Figure 36 Temperature distribution – operation hours at each temperature

Other data used in the calculations: Motor

Generator efficiency 97%

Specific CO2 generation 3.17 kg CO2/kg diesel (default 3.17)

CO2 generation 0.645 kg CO2/kWh

Fuel boiler (heating):

Efficiency 80% Table 35 Input for the calculation The selected topics have been assessed as described in the following.



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11.1 Correct system design In general, we start the HVAC system design in a “wrong” way. The vessel is made to operate on one route. The weather condition on this route is well known, and for an idealized system we would only use these temperatures as design values. The ship must have a set of worldwide conditions. One of our tasks regarding this issue is to make a system for worldwide operations, but fitted to operate in an energy efficient way under actual conditions. This is also the reality for other projects and interesting for us to look into. By correct system design we mean:

� Location of AC room. To minimize ducts in and out of the vessel and to have as short as possible duct routing inside the hull

� Reduce pressure loss � Use systems with high energy recovery rate � Enthalpy exchanger � Oversized units where possible � Correct calculations � Heat transmission calculations � Correct data from heat loads installed in the vessel � Automation system fitted to the actual need � VAV systems to fit the actual conditions and not run with design conditions in normal

operation

11.2 Correct product design Correct product design comes down to choosing products fitted to the actual operation. This is especially for chillers where the operation load will be different from a design (world wide) value and actual load. In general, this is important for all products.

� Chillers with max EER for as many hours as possible through the year � High-efficient enthalpy exchanger � High-efficient fans

11.3 Accommodation results The following results are obtained system by system. A short description of the parameters included in the calculations follows for each system:



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11.3.1 AC 1, Deck 9, MVZ 3 This area has cabin and day rooms, including fitness and dining room. We have not received the specification from the existing Gotland ferry, but show the savings compared to a system also based on enthalpy exchanger. Changes we have made to this specific system:

� AHU is oversized, meaning we use an AHU one size larger than necessary. This is to reduce the internal pressure drop and increase the efficiency of the enthalpy exchanger.

� In addition, a very simple automation system is implemented. We use a VAV system for the public spaces to reduce the air volume to the volume needed to ensure the temperature as well as the proper amount of fresh air in each room. Since this vessel is made for a world wide condition, the full air volume is not needed, and we can reduce the air volume to 3300 m3/h for 12 hours per day.

� Cooling. Standard chillers and standard chiller configuration are normally not adapted to actual loads. We have made a chiller configuration of 4x25% chillers which also ensures high efficiency for low loads. Chiller EER is increased from 2.6 to 3.7.

Results for AC 1, Deck 9, MVZ 3 can be seen in the below table:

Accommodation Chiller

Heating Fan Hum. Units Total Original Energy consumption

kWh / year

121,946 115,971 17,931 2,392 258,240

CO2 production Ton /year 58 75 12 2 146

Green Ship Design Energy consumption

kWh / year 88,479 91,541 12,570 1,504 194,093


Green Ship Savings Energy savings

kWh/year 33,468 24,430 5,361 888 64,147

CO2 savings

Ton/year 14 16 3 1 34

CO2 life time savings Ton

287 315 69 11 682

Table 36 Environmental impact for AC 1, Deck 9, MVZ 3



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11.3.2 AC 2 and 5, Deck 9 and 8, MVZ 2 This area has crew and passenger cabins. Also, the system in this area is compared to a system design based on enthalpy exchanger in a reference vessel. Changes we have made to this specific system:

� AHU is oversized. � VAV system is implemented. The VAV system gives us different types of savings depending

on where the system is used. In crew cabins, we have calculated the air volume according to what is needed to fulfil the temperature demands. In passenger cabins, we have a more sophisticated VAV function. When the cabin is “not in use”, the temperature span will be wider, and we will use less energy for cooling and heating. When the booking system indicates to the system that this cabin will be occupied from the next trip, the room goes into “normal” temperature regulation. We have not simulated this function and have not calculated this saving. Only savings related to air volume to fulfil temperature demands are calculated.

� Chiller EER is increased from 2.6 to 3.7 Results for AC 2 and 5, Deck 9 and 8, MVZ 2 can be seen in the below table:



kWh / year

254,924 158,939 37,408

10,012 461,283



kWh / year 173,473 96,796 24,137 4,740 299,146



kWh/year 81,451 62,143 13,270 5,272 162,137

CO2 savings

Ton/year 34 40 9 3 86


681 802 171 68 1,722

Table 37 Environmental impact for AC2 and 5, Deck 9 and 8, MVZ 2



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11.3.3 AC 3, Deck 9, MVZ 1 This area has crew cabins. Also, the system in this area is compared to a system design based on enthalpy exchanger in a reference vessel. Changes we have made to this specific system are the same as for the system above. Results for AC 3, Deck 9, MVZ 1 can be seen in the below table:



kWh / year

101,160 118,774 15,131 5,247 40,312



kWh / year 59,982 77,913 8,090 4,258 150,242



kWh/year 41,178 40,861 7,040 990 90,070

CO2 savings

Ton/year 16 26 5 1 47


319 527 91 13 950




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11.3.4 AC 4, Deck 8, MVZ 3 This area has passenger cabins only. Same changes as for the system above. Results for AC 4, Deck 8, MVZ 3 can be seen in the below table:



kWh / year

168,219 125,516 24,549 7,070 325,355



kWh / year 103,264 83,025 14,100 5,442 205,830



kWh/year 64,956 42,491 10,449 1,629 119,525

CO2 savings

Ton/year 28 27 7 1 63


553 548 135 21 1,257




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11.3.5 AC 6, Deck 8, MVZ 1 This area is a lounge for passengers. In this area, we have changed the design totally from a system based on cooling and heating from a centralized system to a centralized system serving the area with fresh air only. Heating and cooling are provided by locally mounted fan coils. This reduces the fresh air treatment to a minimum and is the best system to save energy. Fresh air is controlled by CO2 sensors regulating to a minimum when the area is not in use. The average passenger load for the vessel is 624 passengers, meaning that this area can easily be set to no passengers while there will still be plenty of space in other areas. The only purpose of the ventilation system is then to keep the temperature within “reasonable” limits. In this calculation, we have compared a standard system to a fan coil system, and the load on the room to be half capacity on average (24 hours, 365 days a year). These figures can easily be improved by making an easy “use” or “no use” function in the automation system. This gives us the following saving methods:

� Oversized AHU � Design changed from centralized air treatment to fan coil system. � Automation system regulates according to fresh air demand inside the room � Chiller EER is increased from 2.6 to 3.7

Note: These savings can be difficult to compare to the original system. In old systems, the crew very often turn of the system completely when the area is not in use. Results for AC 6, Deck 8, MVZ 1 can be seen in the below table:

Accommodation Chillers Heating Fan Hum. Units Total

Original Energy consumption

kWh/year 392,981 239,929 58,595 16,917 708,423

CO2 production Ton/year 185 155 38 11 388


kWh / year 130,378 84,959 17,776 5,156 238,269



kWh/year 262,603 154,970 40,819 11,762 470,154

CO2 savings

Ton /year 117 100 26 8 251

CO2 life time savings

Ton 2,342 1,999 527 152 5,020




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11.3.6 AC 7, Deck 7, MVZ 3 This system serves 3 lounge zones. The “old” system we compare this system to is enthalpy exchanger. The new design is based on fresh air and heating/cooling by fan coils. The large savings will also in this system occur when the location is in “not in use” mode and can operate in a wider temperature span. It is hard to simulate how much we can close down one area without a detailed passenger number. We have therefore made a simple simulation where we run PS Aft Lounge 1/3 of the time (closed area 2/3) and let the rest of this system run according to temperature needed. This gives us the following saving methods:

� Oversized AHU � Design changed from centralized air treatment to fan coil system. � Automation system regulates according to human fresh air needs inside the room � Automation system closes down when not in use � Chiller EER is increased from 2.6 to 3.7




kWh/year 259,573 162,641 38,151 6,882 467,247



kWh / year 143,063 87,931 19,629 5,493 256,117



kWh/year 116,510 74,710 18,522 1,389 211,131

CO2 savings

Ton /year 50 48 12 1 111


Ton 1,008 964 239 18 2,229




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11.3.7 AC 8, Deck 7, MVZ 2 This system serves serving area and restaurant in the centre of the room and lounges at the sides. It is important for this room to have a solid air volume to make sure that the smell from the food does not spread in the room. This area is vital and will be used when the vessel is in operation. We assume the air volume can be reduced during the night between 0100 and 0700. Between these hours, the air volume is reduced to the air volume needed to maintain operation temperature. The original system is based on enthalpy exchanger. The new design is based on the same, but some of the air volume is reduced, and fan coil systems take some of the load from this area. This gives us the following saving methods:

� Oversized AHU � Design changed from centralized air treatment to fan coil system for some of the volume � Automation system regulates according to closed between 0100 and 0700 � Chiller EER is increased from 2.6 to 3.7


Accommodation

Chillers


kWh/year 296,529 159,509 43,113 1,978 501,129



kWh / year 229,072 124,079 32,748 1,141 387,039



kWh/year 67,458 35,430 10,365 837 114,090

CO2 savings

Ton /year 31 23 7 1 61


Ton 611 457 134 11 1,212




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11.3.8 AC 9, Deck 7, MVZ 1 This system serves Front lounge with 610+50 seats. The system design is based on the below design features. 1. Oversized AHU 2. Design changed from centralized air treatment to fan coil system 3. Automation system regulates according to fresh air demand inside the room 4. Chiller EER is increased from 2.6 to 3.7

Results for AC 9, Deck 7, MVZ 1 can be seen in the table below:



kWh/year 87,284 49,985 12,876 2,309 152,453



kWh / year 37,606 22,462 5,178 1,552 66,799



kWh/year 49,677 27,522 7,697 758 85,655

CO2 savings

Ton /year 22 18 5 0 45


Ton 445 355 99 10 909




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11.3.9 Technical cooling We have based the energy consumption on a maximum technical load like 146 kW. The consumption will be lower when the vessel is berthed, and maximum when the generator load is operating at maximum. We have therefore made an average load based on the vessel operation profile and use, and we have used 146 kW X 46% (average load)= 67 kW. This gives us a saving in energy consumption for chillers by increasing the EER from 2.6 to 3.7: Results for technical cooling can be seen in table below

Accommodation

Chillers


kWh/year 0 0 0 226,278 226,278



kWh / year 0 0 0 159,006 159,006



kWh/year 0 0 0 67,272 67,272

CO2 savings

Ton /year 0 0 0 43 43


Ton 0 0 0 868 868

Table 44 Environmental impact for Technical cooling



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11.3.10 Accommodation and cooling systems in total The savings from the total of AC units inside accommodation will be

Accommodation

Chillers


kWh/year 1,682,666 1,131,264 247,754 279,085 3,114,442

CO2 production Ton/year 802 731 161 179 1,725


kWh / year 965,317 668,706 134,228 188,292 1,797,535

CO2 production Ton/year 490 431 86 123 1,028


kWh/year 717,301 462,557 113,523 90,797 1,316,909

CO2 savings

Ton /year 312 298 74 59 698


Ton 6,246 5,967 1,465 1,172 13,981

Table 45 Environmental impact for accommodation and cooling in total Heating: Heating is obviously important for a vessel travelling this distance. The energy consumption from heating comes from an oil boiler which heats up the air to 18oC and electrical heaters to meet requirements according to the outside temperature. In this calculation, we have not used free heat from the engines when the vessel is at sea. This may reduce the power consumption even more. Fan: The fan energy consumption is reduced by a variable air volume function. Some of this comes from an automation system shutting down areas when possible. Humidification: Normal practice is that humidification will be used less than specified in the building specification. The total kWh/year will therefore normally be too high. We can see that the humidification system uses a lot of energy on this vessel as a result of the operation area. The savings come from the reduced air volume from the original system. Chiller units: The chiller units only have a small impact on the energy consumption. Note that this is only regarding accommodation cooling. The savings come from reduced airflow (VAV) and better EER (energy efficiency ratio) on the chillers. We have for this vessel made an alternative chiller configuration based on 4 chillers, each rated at 25% capacity. The vessel can still operate under World Wide conditions, but the important aspect is the operation in a given operation area. Note: The cooling capacity will be higher when the ship is in operation. We have not been able to implement the heat gain from the sun in these calculations. For the warmest days during the summer, the energy consumption from the chillers will be increased.



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Figure 37 Energy consumption for the accommodation and technical cooling From the graph above, it can be seen that the energy consumption from heating is really important for this system. The potential of using “free heat” from the motors is not included in these calculations.

0

200.000

400.000

600.000

800.000

1.000.000

1.200.000

1.400.000

1.600.000

1.800.000

Acc Heating Acc Fan Acc Hum Chiller ER Fans

Accommodation Summary (kWh)



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11.4 Engine room ventilation The engine room ventilation is also designed to operate at design condition, meaning that a large saving potential is related to variable air volume control according to engine load and temperature outside. This type of demand control has been available for engine rooms for many years, and we can only assume that this is also the case for the existing vessel. Therefore, we will not pay attention to the automation system, but show how much the product design can affect the energy consumption. It is important to highlight that these savings are based on a system with demand control according to temperature and pressure and not a full/half speed system. We have based our calculations on a total air volume like 280,000 m3/h (design volume). We use 4 fans. In this calculation, we have used only supply fans. Engine room “operation” temperature set point for temperature controller is set at 30oC. The same efficiency is used for motor and frequency converter in all calculations. In engine room calculations, it is not easy to estimate the total power consumption. What we focus on here is the difference. Both calculations have the same parameters, and the difference comes only from changing the efficiency of the fan. Fan efficiency is changed from an original efficiency such as 65% to a fan with 87% efficiency. Results for the engine room ventilation can be seen in the table below:

ER

Fans Total


kWh/year 116,461 116,461

CO2 production Ton/year 75 75

Green Ship Design Total Energy consumption

kWh / year 87,011 87,011


Green Ship Savings Total Energy savings

kWh/year 29,450 29,450

CO2 savings

Ton /year 19 19


Ton 380 380

Table 46 Environmental impact for the engine room ventilation For this result, it is better to look at savings in % as we do not try to estimate the energy consumption. By choosing better fans, the potential savings are approximately 25%.



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11.5 Cargo fans (trailer deck ventilation) According to rules, this area needs to be ventilated according to air changes per hour. During loading and unloading, the demand is 30 air changes per hour. During sailing, the demand is 15 air changes per hour. For this vessel:

� Loading/ unloading: 972,000 m3/h � Sailing: 486,000 m3/h

In this calculation, we have used 19 hours’ sailing time and night time (half speed), and 5 hours’ loading/unloading per day. The largest savings for this system can be achieved if we ventilate according to the specific need. The air change rate is now the same for the trailer deck whether one car is loaded or 200. We do not have enough information to carry out this calculation. We will, therefore, show the savings only achieved by fan efficiency. In this calculation, we use half speed 19 hours per day and 5 hours with full speed. Fan efficiency is changed from an original efficiency such as 65% to a fan with 87% efficiency. Results for the optimization of the cargo fans can be seen in the table below:

Cargo Fans

Total


kWh/year 758,077 758,077



kWh / year 566,379 566,379



kWh/year 191,698 191,698

CO2 savings

Ton /year 124 124


Ton 2,473 2,473

Table 47 Environmental impact for the cargo fans. By choosing a better fan, the potential savings are approx. 25% on the cargo fans.



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11.6 Environmental impact In total, the minimum saving potential is more than 1.6 mill kWh per year. These savings can be achieved by using a modern system design, making correct calculations, locating the HVAC rooms on ideal locations, adapting the system to make it fit the actual temperature requirements (and not design temperature) and using high-efficient products. The process starts with correct calculations! HVAC is a wide discipline. There are other important factors, not discussed in this report, which affect the power consumption on a vessel. Insulation factor and reflection factor on windows, insulation of deck heads and bulkheads, colour on shipside/deck head. Our conclusion is to also prioritize the HVAC discipline from an early stage of a project.


Measure CO2 NOx SOx

HVAC Accommodation 42,3% 42,3% X

42,3%

Engine Room Ventilation 25,3% 25,3% 25,3%

Cargo Fans (Trailer deck ventilation) 25,2% 25,2% 25,2%




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12. Light optimisation

By using the existing Ro-Pax lighting drawings, the lighting group could determine the amount and types of light fittings. Afterwards, the challenge was to find new energy saving lighting products and make an energy saving calculation. The lighting group used a well-known lighting technology and a DNV approved calculation system. This calculation system has been used for energy saving projects approved by “NOx fonden” and DNV in Norway. Participants in group: Scan-El

12.1 Methods For the lighting calculations, the following energy saving products have been used. Below are some of the lighting types used for the lighting energy saving calculation. 1. The existing fluorescent light fittings with T8 tubes and magnetic ballast have been replaced with fluorescent T5 tubes with electronic ballast. The lumen output of the light fitting will be the same or increased with the T5 replacement as with the existing T8 light fitting. 1.1: The 2x18W light fitting with T8 fluorescent tubes with magnetic ballast can be replaced

with 1x24W light fitting with electronic ballast. 1.2: The 2x36W light fitting with T8 fluorescent tubes with magnetic ballast can be replaced

with 1.1 1x54W light fitting with electronic ballast. 1.3: The 1x18W downlights with PL tubes and magnetic ballast have been replaced with 1x13W

with PL tubes, electronic ballast and new reflector technology. The lumen output will be the same or increased with the 1x13W light fitting.

1.4: The 100W incandescent bulbs are replaced with 15W LED bulbs. The lumen output will be

the same or increased with the 15W LED bulbs. 1.5: The 1x1000W halogen floodlights have been replaced with 150W LED floodlights The lumen output will be the same, or increased with the 1x150W LED floodlight.

Table 49 Lighting optimizationn savings The lighting calculation is based on T5 technology, PL technology and partly LED technology. The lighting calculation will, in future, be based on a full LED solution. The LED technology is developing so fast so that the watt effect is being reduced, and the lumen output remains the same.

Lighting optimization savings Energy

savings [%] Cost & maintenance, lifetime [EUR]

1. T5 fluorescent tubes, and LED 61 362,416

2. Full LED 71 429,530



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When the new building takes place, there will be much better energy saving possibilities with the newest LED technology than the above mentioned lighting calculation. It is also possible to dim the light in some places on board the ship and to use sensor technology in corridors, store room etc. where there could be minimum or no light when there are no people in the areas. This will also increase the savings.

12.2 Environmental impact Changing to T5 fluorescent tubes and full LED reduces the energy consumption from lights by 61% and 71%, respectively. This corresponds to a saving of 307,208 kWh/year or 4.48 ton NOx/year and 154 ton CO2/year. In this calculation, savings on the cooling system due to lower heating from the fitting is included. These savings are not included in the results from the HVAC group.


Measure CO2 NOx SOx

Light optimization 67.0% 67.0% 67.0%

Table 50 Emission reduction for ligt optimization



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13. Technical conclusion

Figure 38 Rendering of the final design From the project was initiated, there were two goals – one was the cooperation and knowledge sharing among the participating stakeholders, the other was a technical optimisation of the vessel’s design. The project has been concluded with significant difficulties. The project execution has suffered from lack of resources among some of the participating companies, and especially in coordinating this large group of stakeholders, the long execution time has led to a reduced interest among the stakeholders. This process had been foreseen from the beginning of the project, but it has surprised all the participants. The knowledge sharing among the companies participating has reflected their involvement during the project. The stakeholders contributing to the process have also gained a high degree of knowledge and improved their network. From a technical perspective, it can, however, be concluded that it is possible to reduce the fuel consumption considerably by introducing new technologies without changing the operational parameters. The effects of the optimisation and the selected technologies have led to a fuel cost saving of 22.9%. The stated pay back period/return on investment (ROI) is naturally strongly depending on the bunker costs and the spread between HFO/MGO/LNG. This saving is significant though very dependent on the future cost of fuel. Hence, the comparison of the technologies has been made based on the existing vessel’s operation on HFO. The price of HFO and LNG have been set at 0.017 $/MJ for both types of fuel.



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All the technologies included in the design have a payback time of less than 5 years, and hence all investments can be depreciated during the owner’s contract period. The overall goal of the project was to save more than 25% CO2.



LNG Total 25.1%%

~92% 98% 98%

CRP Propulsion/hullform optimization 12.7% 12.7% 12.7% 12.7%

Shore power 3.6% 3.6% 3.6% 3.6%

LNG Cooling 1.5% 1.5% 1.5% 1.5%

VSD 0.9% 0.9% 0.9% 0.9%

HVAC Accommodation 42.3% 42.3% 42.3% 42.3%

Engine Room Ventilation 25.3% 25.3% 25.3% 25.3%

Cargo Fans (Trailer deck ventilation) 25.2% 25.2% 25.2% 25.2%

Light optimization 67.0% 67.0% 67.0% 67.0%




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14. Collaborative development

14.1 The project The project was unique because those who participated had a variety of competences and came from a variety of organisations. In the project, they worked together to map possible energy and operation synergies. The project had several phases. In the first phase, each subproject calculated possible energy savings in relation to the existing Ro-Pax ferry on the Gotland-Visby route, and on the basis of these calculations, they, i.e. the participants in the subprojects, recommended possible solutions to the design of the new ferry. The next phase was a design phase in which a preliminary design was developed that reflected and integrated the solutions from the first phase. This phase was carried out by the subproject Design. In the following phase, the subprojects calculated possible energy savings and came up with new solutions based on the design of the new Ro-Pax ferry. In the last phase, solutions and calculations were to some extent integrated into the design of the new ferry, and a report for Green Ship of the Future was written. Originally the project had 7 subprojects:

� Design � Heat, Insulation, Ventilation and Cooling � Electrical Systems, Lights and Control � Weight � Machine and Components � Logistics and Onshore Operation � Water

It was not possible to find participants for two of the subprojects; consequently they have not been part of the project. These subprojects were:

� Logistics and Onshore Operations � Water

14.2 The process The project was divided into phases with the intention of enhancing the continuous updating of the participants’ knowledge. Four workshops have been held during the project to enable networking and cooperation. In the workshops, the participants have met to work and calculate in cooperation, and there have been many opportunities for discussing the project and the challenges in it. The process had been planned to provide the participants with the opportunities for cooperative work besides the workshops. In each of the subprojects, a group leader had been responsible for the work within the subproject and for the continuous dialogue with the project manager. The intention was that reporting from each of the subprojects would take place at the two workshops



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that ended phase 1 and 3, whereas the two other workshops should kick-start the work in the subprojects. A facilitator from Including People had been responsible for the planning and facilitation of the workshops. The intention with the kick-starting workshops was to:

� Provide the participants with opportunities for meeting participants from the other subprojects

� Provide input from the existing Ro-Pax ferry connection Gotland-Visby � Provide input to the improvement potential in relation to energy consumption on the

existing ferry connection � Provide input to the suggested improvements in relation to energy consumption on the

new ferry connection � Meetings in the subprojects to agree on the work tasks and schedule until the next

workshop The intention with the reporting workshops was to:

� Provide status of the subprojects � Provide input to the work in the subprojects including improvement suggestions � Provide coherency between the subprojects � Provide opportunities for knowledge sharing about the project and in general

Figure 39 Development process In relation to each of the phases, there have been challenges and advantages. The most important advantage has been that the participants have gained a more extensive understanding of the



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possibilities for reduction of energy consumption for each individual solution, and also how each solution can influence other energy consumption areas. This has provided more extensive and enhanced solutions in relation to energy reduction as more conditions have been researched and evaluated. Another advantage in this project has been that the participants have gained more insight into the competences in the other companies and have shared knowledge in the subprojects. Moreover, the participants have felt involved in the design process and thereby have felt that they have contributed to the final solution. In a project with many subprojects and participants from different companies, there are many challenges. One of the challenges has been that the participants are from different companies and physically distanced from each other in the subprojects. Another large challenge has been that the group leaders have not had authority in relation to reward and punishment of the participants, and thereby it has been difficult to motivate some of the participants to contribute to the project. This challenge has also been part of the overall project manager’s challenges in relation to the project. Another challenge that influences the participants’ contributions is that the tasks in the project have been non-profit and thereby something that had to be done between profit-making work tasks in the participants’ respective companies. The two workshops have been characterised by the fact that not all participants have been able to participate. Some participants in the projects have participated only in one or none of the workshops, thereby being less familiar with the other participants. This can impede the knowledge sharing for all participants. Moreover, some of the participants in the project changed jobs and thereby left the project which also caused problems in relation to completion and knowledge sharing. All the workshops have been facilitated to ensure that the participants had opportunity to contribute to and benefit from the project.

14.3 Workshop 1 In the first workshop, the participants gained an understanding of the content and ideas of the projects. The workshop created a shared understanding of the design of the existing Ro-Pax ferry and its advantages and challenges. The participants were divided into smaller groups and discussed from a positive point of view what worked and what could be improved on the existing Ro-Pax ferry. In the last part of the workshop, each subproject started their cooperative work through distribution of work tasks and agreements on how to keep contact between the workshops.

14.4 Workshop 2 In the second workshop, the facilitator used graphic facilitation, partly to present the process of the project, partly as a starting point for the work in the groups. Each subproject created short presentations after which the participants went to different tables to hear the presentations and provide input to further improvements. The method is called café presentations. As there were more than one presentation at the same time, and the participants walked around, there was energy in the room, and the participants could hear that something happened at the other tables. In plenum, the facilitator collected the inputs to each subproject and ideas on how to make the subprojects contribute to results for the overall project.



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In this workshop, there was also focus on the boundaries between the subprojects. This was done to provide the group leaders and the project manager with an overview of the areas where coordination between subprojects was necessary. As a result of the first reporting workshop, another coordination mechanism was included in the project, i.e. group leader meetings. The meetings were used to coordinate between the subprojects and subprojects and the Design project. The meetings were also used to report on progress in each of the subprojects and as a decision-making arena. These meetings were partly physical and partly telephone meetings which created some challenges in relation to participation in, and contribution to, the meetings.

14.5 Workshop 3 The second workshop to kick-start a new phase in the project was about the design of the new Ro-Pax ferry. In groups that once more were composed of participants from different subprojects, the participants worked with ideas on how the Ro-Pax ferry could be adapted to a varied load, and how this would influence the design. Some questions were not clarified in relation to propellers and pods, and these made up an extensive part of what the participants worked with in the groups as no solution would reduce energy consumption sufficiently. In the group presentations, the groups described their solutions to other energy reduction areas, but even though two groups had discussed different solutions to the problem of propellers and pods, these solutions were not presented in plenum. The facilitator invited the groups to present their solutions. These solutions had a large impact on the final solution for propellers and pods and thereby the design of the Ro-Pax ferry.

14.6 Workshop 4 In the last workshop, the project and the process were evaluated. The expectations to the cooperation between the project managers from OSK-Shiptech and Green Ship of the Future, respectively, were raised as problematic as there had been little cooperation, and because neither had presented their expectations. The participants suggested that, in future projects, project management and Green Ship of the Future agreed on how the cooperation should be and presented their respective expectations to the project, process and cooperation. Project management was another issue raised as some felt that the communication between project management and the participants could have been better. Project management did present a project plan, but most participants felt that the project plan as well as changes in the project plan and milestones should have been communicated better. Another issue raised was role expectations, i.e. how Green Ship of the Future could participate more actively in the project and how group leaders should be drivers of their groups. External communication was another area of criticism as there has been no external communication about the projects except what the project manager and the group leader of the machine group had presented at conferences and in articles in magazines. In the future, updates on Green Ship of the Future’s website would enhance the communication.



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There was a more positive attitude towards other parts of the project and process. The participants in the workshop found that knowledge sharing in the project had been excellent, especially those who had been group leaders and those who had participated actively in the project and in the workshops. In some groups and in the workshops, the participants had been active and committed in the process and the project. The shipowner had provided the necessary information when asked, which had made the technical discussions and solutions possible.

14.7 Summary The facilitated and planned workshops have been an important part of the process. The planned workshops made the interaction easier and provided an arena for knowledge sharing. The facilitator made sure the meeting plans were followed, and that interaction between participants was enhanced. The process with workshops and subprojects that work in between and during workshops has provided an enhanced knowledge sharing between the subprojects and the participants. The facilitated workshops have provided opportunities to work with the subprojects and ensured knowledge sharing together with the opportunity to comment on and contribute to other subprojects than the one of which each participant had been a part. A facilitator with focus on the process and not the content enabled the knowledge sharing and work in the workshops. In this project, the facilitator planned the workshops with the intent to:

� Ensure knowledge sharing in the project and about the competences in each of the participating companies

� Ensure that the subprojects coordinated their contributions � Ensure that the participants worked with solutions � Ensure that the necessary decisions were made in relation to:

o What work tasks the subprojects should continue to work with o The design o The process in the project, e.g. the introduction of group leader meetings

The facilitator has ensured that, during the workshops, the participants have worked with solutions or commented on existing solutions, i.e. the groups have worked with the tasks provided in the workshops. The role of the facilitator has, at the same time, been to ensure that relevant solutions and comments not related to the work tasks in a given context were collected. An example was the solutions to the placement of propellers and pods that was discussed at the second workshop to kick-start a phase as these solutions had a decisive influence on the final solution. Cooperation in a project with many stakeholders and where most participants cannot invoice the hours they work on the project provides challenges in relation to completion of the work tasks in the subprojects. In this project, we experienced that even though the group leader meetings made coordination and reporting easier, the deliveries agreed on were still delayed.



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Workshops planned and facilitated by a facilitator made room for cooperative work on challenges in the subprojects in each of the workshops. This provided an opportunity for a more coherent understanding of the project and the subprojects for those participating in the workshop and the opportunity to share knowledge between participants from different subprojects. Unfortunately, some participants did not participate in the workshops, others only participated in some of them. The facilitator ensured that solutions and comments were collected to give the project manager an overview of decisions and the extent of the completion of subprojects.

15. Acknowledgement Green Ship of the Future wishes to thank the Danish Maritime Fund for financial support to partly fund this project. Furthermore, Green Ship of the Future wants to thank the maritime industry in Denmark for the encouragement and support in both the present project and in all our work towards greener shipping.



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16. References

/1/ Rederiaktiebolaget Gotland, Ro-Pax 2000, Building specification. /2/ Lloyd's Register's Rules and Regulations for the Classification of Ships, Part 3 and 4. /3/ Lloyd's Register's software for design assessment, RulesCalc. /4/ ISO 3046-1 – Reciprocation internal combustion engines – Performance – Declarations of

power, fuel and lubricating oil consumptions, and test methods – Additional requirements for engines for general use

/5/ http://www.voithturbo.com/applications/vt-

publications/downloads/1881_e_g_2247_e_steamtrac_steamdrive_2012-08_screen.pdf /6/ http://www.wartsila.com/file/Wartsila/1278511902083a1267106724867-engine-

combined-cycle-with-internal-combustion-engines.pdf /7/ http://www.mandieselturbo.com/files/news/filesof17326/TCS-

PTG%20Savings%20with%20Extra%20Power.pdf /8/ THE FUTURE SHIP: A STUDY BY WARTSILA DIESEL, Schip en Werf 56 (1989), p.282 (Aug.)

[4 pp., 12 fig.] /9/ IPCC, Working Group I: The Science of Climate Change, IPCC Fourth Assessment

Report : Climate Change, 2007.



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17. Table of tables

Table 1 Main particulars and engine data ................................................................................... 3 Table 2 Distance and compilation of route schedule ................................................................... 4 Table 3 Operation modes and power requirements .................................................................... 5 Table 4 IMO carbon conversion factors /8/ ................................................................................. 7 Table 5 Fuel prices used in calculations ..................................................................................... 8 Table 6 Main particulars for existing vessel and new low emission vessel design....................... 9 Table 7 Draughts and weighting ............................................................................................... 14 Table 8 Calculated (RANS CFD) resistance, effective power and dynamic sinkage and trim* .. 15 Table 9 Calculated (RANS CFD) resistance, effective power and dynamic sinkage and trim* .. 16 Table 10 Emission reduction list of different measures ............................................................. 18 Table 11 Midship sections (* Concept 1 - Full Effective Midship Section) .................................. 23 Table 12 Steel weights for the different concepts ..................................................................... 23 Table 13 Weight optimization results ........................................................................................ 24 Table 14 Emission reduction list of different measures ............................................................. 24 Table 15 Benefits/Disadvantages – HFO with scrubber ............................................................. 27 Table 16 Benefits/Disadvantages – MGO .................................................................................. 27 Table 17 Benefits/Disadvantages – LNG ................................................................................... 28 Table 18 Benefits/Disadvantages – Methanol............................................................................ 29 Table 19 Benefits/Disadvantages – DME ................................................................................... 30 Table 20 Initial machinery configuration alternatives................................................................. 32 Table 21 Pros and cons of different machinery alternatives (+ indicates more benefit) ............. 32 Table 22 Machinery configuration alternatives .......................................................................... 34 Table 23 Pros and cons of different machinery alternatives (+ indicates more benefit) ............. 35 Table 24 Propeller power requirement comparison .................................................................. 37 Table 25 Engine power requirement including mechanical and electrical losses ........................ 37 Table 26 Emission reduction for CRP and hullform .................................................................. 37 Table 27 Emission reduction from shore power ........................................................................ 38 Table 28 Emission reduction from harbour generator ............................................................... 39 Table 29 Payback time list of different measures ...................................................................... 52 Table 30 Emission reduction list of different measures ............................................................. 52 Table 31 Relative savings - Environmental and economic effect of measures .......................... 53 Table 32 Methanol and DC-Grid solution .................................................................................. 53 Table 33 EEDI values comparison between GSF and Visby ..................................................... 54 Table 34 Environmental impact................................................................................................. 58 Table 35 Input for the calculation ............................................................................................. 60 Table 36 Environmental impact for AC 1, Deck 9, MVZ 3 .......................................................... 62 Table 37 Environmental impact for AC2 and 5, Deck 9 and 8, MVZ 2 ...................................... 63 Table 38 Environmental impact for AC 3, Deck 9, MVZ 1 ......................................................... 64 Table 39 Environmental impact for AC 4, Deck 8, MVZ 3 ......................................................... 65 Table 40 Environmental impact for AC 6, Deck 8, MVZ 1 ......................................................... 66 Table 41 Environmental impact for AC 7, Deck 7, MVZ 3 ......................................................... 67 Table 42 Environmental impact for AC 8, Deck 7, MVZ 2 ......................................................... 68 Table 43 Environmental impact for AC 9, Deck 7, MVZ 1 ......................................................... 69 Table 44 Environmental impact for Technical cooling ............................................................... 70 Table 45 Environmental impact for accommodation and cooling in total ................................... 71 Table 46 Environmental impact for the engine room ventilation ................................................ 73 Table 47 Environmental impact for the cargo fans. ................................................................... 74 Table 48 Emission reduction list of different measures ............................................................. 75 Table 49 Lighting optimizationn savings ................................................................................... 76



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Table 50 Emission reduction for ligt optimization ...................................................................... 77 Table 51 Emission reduction list of different measures ............................................................. 79

18. Table of figures

Figure 1 M/F Gotland – The reference vessel ............................................................................. 2 Figure 2 Map of routes ............................................................................................................... 4 Figure 3 Speed plot of Nynäshamn-Visby route.......................................................................... 4 Figure 4 Operation profile Nynäshamn-Visby route .................................................................... 5 Figure 5 Power consumption profile ........................................................................................... 6 Figure 6 Price and volume of different fuel alternatives .............................................................. 8 Figure 7 The counter rotating Azipod unit version of the vessel ................................................ 10 Figure 8 The counter rotating Azipod unit version of the vessel – MA in profile ........................ 10 Figure 9 The counter rotating Azipod unit version of the vessel – MA in planview .................... 10 Figure 10 The counter rotating Azipod unit version of the vessel – MA in planview – tank top .. 11 Figure 11 Ramp arrangement - Upper deck ............................................................................. 11 Figure 12 Ramp arrangement - Main deck ................................................................................ 12 Figure 13 Example of CFD plot. Initial hull form (Model 20), wave pattern, 5.87 m draught ...... 15 Figure 14 Example of CFD plot. Optimized hull form (Des 032), wave pattern, 5.87 m draught 16 Figure 15 CFD plot comparing initial and optimised hull forms (Model 20 and Des 032), wave pattern, 5.87 m draught ............................................................................................................ 17 Figure 16 Speed and power curves. ......................................................................................... 18 Figure 17 Required steel weight for different wheel loads ........................................................ 21 Figure 18 LNG terminal under construction in Nynäshamn (May 2010, Linde Group)............... 28 Figure 19 Sketch of methanol tank configuration ...................................................................... 31 Figure 20 Machinery alternative 3 - DE Azipod CRP ................................................................ 35 Figure 21 Propeller power requirement comparison vs. speed ................................................. 36 Figure 22 General flow diagram of a typical steam turbine system ........................................... 40 Figure 23 ORC system from Turboden S.r.l. ............................................................................. 41 Figure 24 MAN Diesel & Turbo TCS-PTG ................................................................................ 43 Figure 25 Voith SteamTrac/SteamDrive system, /5/. ................................................................ 43 Figure 26 Fuel savings due to colder charge air (ISO 3046) ..................................................... 44 Figure 27 Capacity and head of different pump alternatives ..................................................... 46 Figure 28 Total fuel expenses per year isolated for cooling with or without optimized VSDs ..... 47 Figure 29 MVDC grid single line diagram ................................................................................. 49 Figure 30 Example of SFOC curve for with and without DC-Grid ............................................... 50 Figure 31 Fuel costs comparison first year ............................................................................... 51 Figure 32 Fuel costs and CAPEX for machinery and fuel alternatives over 20 years ................ 51 Figure 33 Relative savings ........................................................................................................ 58 Figure 34 Temperature distribution - Gotland ........................................................................... 59 Figure 35 Temperature distribution - Nynashamn (Stockholm) ................................................. 60 Figure 36 Temperature distribution – operation hours at each temperature ............................. 60 Figure 37 Energy consumption for the accommodation and technical cooling........................... 72 Figure 38 Rendering of the final design .................................................................................... 78 Figure 39 Development process ................................................................................................ 81

technical report ver08 final - cds€¦ · b final version project team crs/anh cds 18-11-2015 a...

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