The optimal load profile for the nieuw statendam

THE OPTIMAL LOAD PROFILE

FOR THE NIEUW STATENDAM A thesis concerning the most effective way of

Sailing

Authors: Michael Spaan

Study year /semester: 2020 semester 8

HZ University of Applied Sciences

Coach: B. Ooms

Place: Vlissingen

Date: 26-05-2020

Version number: 1

The optimal load profile for the

nieuw statendam

A thesis concerning the most effective way of

Sailing

Thesis

Place: Vlissingen

Date: 26th of May, 2020

Studentnumber: 71090

Study year: 4th

Semester: 8th

Hz University of Applied Sciences

Coach: B. Ooms

Version number: 1.1

Preface In order to graduate from the University of Applied Sciences and obtain my

bachelors degree, I had to conduct research into a subject of my choosing. This

research would be conducted on board of the Nieuw Statendam, the newest fleet

member of the Holland America Line. The results of this research would have to be

displayed in a report, a Thesis.

Finding a subject was difficult at first. There are many different ways of conducting

research on board and I wanted to do something original, not something that was

done before. I reached out to the Chief Engineer of the Nieuw Statendam, at the

time being Peter Massolt, who supplied me with a subject that peaked my interest. I

discussed the subject with my coach B. Ooms who thought it was a great idea. After

writing my research proposal and getting it approved I was off to the Nieuw

Statendam to execute my very own research project.

Most of my previous projects were done in a group, so having to do this alone was

both exciting and challenging. It was a lot more difficult to find every thing I needed

and to put all of that found data on paper, but after many hours, my Thesis was

done.

I would like to thank Peter Massolt for supplying me with this subject. I would also like

to thank Chief Engineer Bonni Galema, Staff Chief Engineer Wim Akkerman and the

entire engine room crew of the Nieuw Statendam for helping and guiding me with

this project. I have enjoyed sailing with these crewmembers and this ship immensely.

Thank you to my coach B. Ooms, who always helped me as soon as possible and

helped guide me in the introduction phases of this research.

Abstract The Nieuw Statendam is equipped with a program called ENIRAM. This program

calculates the optimal engine configuration and load expressed in revolutions per

minute of the propellers. The issue with this program is that it only looks at he main

power plants and does not take the waste heat recovery system into consideration.

This can lead to a drop in waste heat recovery, which can lead to a loss of overall

efficiency.

When the engine loads drops below a certain point, the heat extracted from the HT

system and the exhaust gasses becomes so little that certain systems, such as the

evaporators, need to be shut off. The auxiliary oil fired boiler would also need to start

burning fuel in order to produce more steam.

The purpose of this research was to calculate the minimal operational loads for

optimal waste heat recovery. This was done by calculating the amount of heat

stored in the HT system and in the exhaust gasses flowing through the exhaust gas

boiler. By calculating the amount of heat in these systems under different engine

loads, a graph was created using Microsoft Excel, clearly showing a drop in waste

heat recovery beneath a certain load.

Measurements were taken under eight different loads and compared between one

another. Results were both taken in a two engine configuration and a three engine

configuration. All results were obtained in summer conditions, as the vessel was

sailing in the Caribbean at the time of data collection.

All results were placed in a graph. The results showed a significant drop in waste heat

recovery below 70%. Both engine configurations showed the same results. It could

therefore be concluded that the minimal operational load for optimum waste heat

recovery lies at 70%.

It is recommended to continue this research on other vessels working with the

ENIRAM program.

Table of contents 1.0 Introduction ................................................................................................................... 1

2.0 Theoretical Framework ................................................................................................. 2

2.1 ENIRAM ....................................................................................................................... 2

2.2 Waste heat recovery ................................................................................................. 2

2.3 Exhaust gas boilers ..................................................................................................... 3

2.4 Optimal loads ............................................................................................................ 4

2.5 Minimal loads ............................................................................................................. 4

2.6 Optimal engine parameters ..................................................................................... 5

2.7 Conceptual framework ............................................................................................ 6

2.8 Abbreviations ............................................................................................................. 6

3.0 Research Method ......................................................................................................... 7

4.0 Results ............................................................................................................................. 8

4.1 HT system heat calculations ..................................................................................... 8

4.2 Exhaust gas energy calculations .............................................................................. 9

4.3 Waste heat recovery baseline ................................................................................11

4.4 Two engines configuration.......................................................................................12

4.5 Three engines configuration ....................................................................................15

5.0 Discussion ......................................................................................................................17

6.0 Conclusion ....................................................................................................................19

6.1 Waste heat recovery conclusions ...........................................................................19

6.2 recommendation .....................................................................................................19

Reference list ......................................................................................................................20

Appendix 1: Fresh Water Generator Technical Data .....................................................21

Appendix 2: Diesel Engine Acceptance Test Records ...................................................22

Appendix 3: Exhaust Gas Data Diesel generator ............................................................23

Appendix 4: Steam Flow and Thermal Balance sheet ....................................................24

Appendix 5: Two engine configurations Two engine configuration at 80% load .........25

Two engine configuration at 75% load .........................................................................26







Appendix 6: Three engine configuration .........................................................................33

Three engine configuration at 80% load ......................................................................33








1

1.0 Introduction The Holland America Line fleet is equipped with a management tool for vessel and

fleet efficiency. This tool, called Eniram, is a software platform which calculates the

most efficient configuration for a certain passage expressed in the revolutions per

minute (RPM) of the propeller. In order to calculate this configuration, many different

parameters such as the weather and current information are gathered. A display on

the bridge shows a certain “bandwidth” indicated in a green colour with a red

border on either side. The objective is to sail the ship “in the green”, for optimum fuel

efficiency. The software is developed by Eniram, which has recently been acquired

by Wartsila. (Wartsila, 2020)

The problem however, arises when the Eniram system has calculated a passage to

be sailed with an RPM not completely compatible with the overall optimal efficiency

of the power plant. For example, if the suggested RPM for fuel savings is 90, the

electrical load of the diesel generators (DG’s), may be around 65% while running

three DG’s. The power plant, its cooling and waste heat recovery system has been

designed for an 85% load for the optimum amount of heat available for use. When

the electrical load drops below a certain level, the steam production of the exhaust

gas boilers (EGB’s) drops significantly, as well as the amount of available waste heat

in the cooling system. This may lead to a shutdown of the evaporators and the heat

being used for air conditioning (AC) reheating and potable water heating. When this

happens the auxiliary boiler will need to start running, which results in higher fuel

costs. (Line, 2018)

The goal of this research is to establish a matrix in which a maximum allowable

minimum load can be selected, at the edge of where waste heat recovery

becomes unmanageable without the boiler starting up. When this research is

concluded, the optimal way of sailing, in terms of the overall efficiency of the power

plant will be calculated.

The main question of this research is; “Which engine load profile, considering the

operation of the entire plant, is the most fuel and cost effective?”. To answer this

question, the following sub questions have been answered;

- What is the minimum operational load for optimal effective waste heat

recovery concerning the HT cooling circuit?

- What is the minimum operational load for the most effective steam

production of the exhaust gas boilers?

This thesis will consist of a theoretical framework, which includes a conceptual

framework. The followed by the explained methods for gathering information for the

answers to the sub and main questions. After which the results will be displayed, the

results will be discussed and finally, concluded.

2

2.0 Theoretical Framework

2.1 ENIRAM

Eniram was founded in 2005 by a Finnish software engineering company specializing

in marine energy management products. The company provides these products for

operators of different commercial vessels, such as cruise ships, bulk carriers, container

ships and tankers. The energy management systems provide operators with some

insight into reducing emissions, increasing fuel efficiency and optimizing the overall

ship and fleet performance. It is currently owned by Wärtsilä. Wärtsilä explains the

program increases efficiency by collecting data from different areas, such as the

weather, hull and propeller performance, the optimum trim model and the

parameters of the running power plant. (Eniram, 2020) (Wartsila, 2020)

Figure 1: The different data collected by the Eniram software (Wartsila, 2020)

2.2 Waste heat recovery

Despite the high brake efficiency of diesel engines, the engines waste large amounts

of heat to the environment, especially in exhaust gasses (Francesco Baldi, 2014). By

implementing waste heat recovery (WHR) system, this wasted energy can be used to

increase the overall efficiency of the power plant and therefore reduce the costs

and the environmental impact of the entire power plant. It is also stated that the

employment of a WHR system results in reducing the fuel consumption. As an effect

of an WHR system, there is a lowered cost of purchased fuel, a lower amount of

emitted exhaust gas components and an extended operational period of machines

and devices on a ship (Behrendt, 2019). (Min-Hsiung Yang, 2014) Also states; “To

increase energy efficiency and to reduce fuel consumption, WHR is a significant

method for energy saving.”

(Ouyang, 2019) Also states that WHR technology is widely used in large ships usually

applying waste heat boilers (WHB), also known as economisers. Utilizing the steam

produced in the WHB’s, heat for sustaining daily life can be provided, as well as

Heavy Fuel Oil (HFO) tank heating, purifier heating, fresh water evaporator

3

preheating, laundry and galley heating and even swimming pool heating. (Line,

2018)

2.3 Exhaust gas boilers

Exhaust gas boilers, known as economisers (ECO), are used to extract heat from the

exhaust gasses emitted by the main diesel engines and utilize that heat to produce

energy. This energy is usually stored in superheated water, steam, which can then be

used for multiple applications in the overall power plant. (Laval, 2020)

The ECO can be optimized by

ensuring the maximum amount of

energy is transferred from the

exhaust gasses to the medium, in

this case water, which needs to

be superheated. By pre-heating

the feeding water supplied to the

ECO more steam can be

generated. (Behrendt, 2019)

found that each temperature

increment of 10 Kelvin of the

feeding water increases the

amount of steam generated by

3%, regardless of the steam

pressure. This can be seen in

figure 2.

A significant factor limiting the use of waste heat contained in exhaust gasses is low

temperature corrosion (LTC). LTC is the result of the oxidation process of sulphur,

which is found in the exhaust gasses (Behrendt, 2019). Condensation of the acids

created during the oxidation process results in metal wastage, boiler tube failure and

air preheater corrosion (Sathyanathan, 2012).

Figure 2: The relation between the temperature of the feeding water and the generated steam (Behrendt, 2019)

4

2.4 Optimal loads

All ECO’s and other waste heat recovery systems are designed to run at an optimal

load. Usually for a marine diesel engine system operating with a WHR system, this is a

85% load (Line, 2018). The load of the system can drastically change the output of

the WHR system. Two main factors contributing to a lower WHR energy output are a

decrease in the mass flow of the

exhaust gasses from the diesel

engines and a decrease in the

temperature of the exhaust gasses

(Ouyang, 2019).

Figure 3, gathered from the

research of (Ouyang, 2019), clearly

shows the decreased thermal

efficiency of an engine operating

at lower loads. It can therefore be

concluded that the thermal

efficiency is at its best around a

85% load.

2.5 Minimal loads

When the engine load drops below a certain level, the WHR systems will see a drop

in efficiency (Line, 2018). It can therefore be said that the minimal effective load of

the WHR system is found just before the steep decrease in efficiency.

When the waste heat supplied by the engines is not sufficient enough to supply the

auxiliary systems with the required amount of heat, the auxiliary boiler will need to be

started (Line, 2018). Starting the auxiliary boiler will require more fuel to be burned,

resulting in higher total fuel costs.

Figure 3: Engine load percentage compared to the

thermal efficiency percentage of an Economiser

5

2.6 Optimal engine parameters

Engines are designed to run at a high load to run at the highest possible efficiency

(Ouyang, 2019). When an engine is running at low loads for an extended period of

time, severe fouling may occur on the turbocharger and ECO. When the engine is

running at low loads, the turbocharger runs on a lower RPM. This causes less air to be

supplied to the engine, thereby causing inefficient combustion (Frozee, 2014).

Inefficient of incomplete combustion will occur when there is not sufficient oxygen

during the combustion process to allow for all the fuel to be burned. This causes

carbon and carbon monoxide to be formed instead of carbon dioxide. The carbon

produced during an incomplete combustion may stick to the inside of a

turbocharger or ECO, causing loss of efficiency (BBC, 2020).

(Koster, 2015) Claims that harmful emissions such as carbon based particles, are

produced when incomplete combustion occurs. These carbon based particles get

expelled into the turbocharger and ECO, causing fouling. A number of faults

occurring due to fouling are reluctant starting, constant surging of the turbocharger

and the charge air pressure being too high (Quruvignesh, 2020).

(Woodyard, 2004) Also claims that particle matter (PM) consisting of inorganic and

organic compound is produced by incomplete combustion, partly unburned lube

oil, ash in the fuel and lube oil, sulphates and water. More than half of the total

particle mass is soot, whose visible evidence is smoke. PM can cause a build-up of

soot which can have negative effects on the efficiency of the turbocharger and the

EGB.

Imperfect combustion due to an engine running at low loads may lead to an

increase in carbon monoxide and hydrocarbons. The hydrocarbons can be

damaging for your engine and reduce the efficiency of the turbocharger due to

fouling. When the turbocharger is running at a lower efficiency, less air is getting

supplied to the engine and the combustion process effectiveness declines. This

causes even more hydrocarbons and harmful gasses to be expelled from the

engine. (Kuiken, 2008)

6

2.7 Conceptual framework

The main question; “Which engine load profile, considering the operation of the

entire plant, is the most fuel and cost effective?”, is shown at the top of figure four.

From the main question the following sub questions are formulated;

- What is the minimum operational load for optimal effective waste heat

recovery concerning the HT cooling circuit?

- What is the minimum operational load for the most effective steam

production of the exhaust gas boilers?

2.8 Abbreviations

The following is a list of abbreviations used in the thesis.

RPM Revolutions per minute

DG Diesel generator

EGB Exhaust gas boiler

AC Air conditioning

WHR Waste heat recovery

WHB Waste heat boiler

HFO Heavy fuel oil

ECO Economiser

LTC Low temperature corrosion

PM Particle matter

Figure 4: The conceptual framework

7

3.0 Research Method

In order to gather all the information required to answer the main and sub questions,

a quantitative research method was used. The reason being, all questions relate to

data which can be gathered at different operational loads. All sub questions need

different data sets to be answered and will therefore all be researched quantitively.

The data was collected on board the MS Nieuw Statendam. The research method

can be applied to all ships running the Eniram program although the found results

only apply to the Nieuw Statendam. The required data was obtained by taking

measurements of the in and outlet temperature of the HT water and the exhaust

gasses. These measurements were taken at different engine loads and then

compared to each other. Different engine configurations were also considered. The

following loads were used as measurements;

- 80%

- 75%

- 73%

- 70%

- 69%

- 60%

- 55%

- 52%

The data collected at these loads was then used in multiple calculations, which are

explained in more detail in chapter 4.1 and chapter 4.2. Microsoft Excel was used as

a platform to visualize all calculations made. All these excel sheets can be found in

appendix five and appendix six. Due to complications arising from the COVID-19

outbreak, not all data gathered was so called “Live data”. Older data sheets

containing all necessary information were used. More information about this issue

can be found in chapter 5.0

Any sensitive and confidential information gathered during this research is not and

will not be published or shared with any third party.

8

4.0 Results

4.1 HT system heat calculations The results were acquired by different calculations. In order to determine the amount

of heat stored in the HT cooling system, the following calculations were made.

𝑄 = 𝑐 ∗ �̇� ∗ ∆𝑇

Q = The amount of energy in KW

c = the specific heat of water in kJ/KgK

m = The mass of water flowing through the engine in Kg/s

ΔT = The difference in temperature of the HT water flowing through the engine in °C

The Temperatures were taken from the DG’s mimics. The DG’s have temperature

sensors located at the entrance and exit of the HT water system, showing the exact

temperature difference at any given time. As the load of the DG’s increased, so did

the temperatures of the HT water, therefore containing more energy, which could

then be used by consumers.

The amount of water flowing through the engine was kept at a constant flow. The

engine has an engine powered centrifugal HT pump, meaning the pump is powered

by gears connected to the crankshaft of the engine. The engine is always running at

the designed RPM, in this instance being 514 RPM. Therefore, the pump will also

always be running at a constant speed, therefore producing a constant flow. The

flow was found to be approximately 442 m3 per hour, as seen in appendix 1. The flow

used in the calculations was formulated in Kg’s per second. Therefore, the following

calculation was made.

𝑀 = (𝑚

3600) ∗ 1000 ∗ 𝜌

M = The flow of water in Kg/s

m = The flow of water in m3/h

ρ = The specific mass of the HT water

In order to get from hours to seconds, the flow is divided by 3600. In order to get from

m3’s to Kg’s, the mass is multiplied by 1000 (because there are 1000 liters of water in

one cubic meter of water) and then by the specific mass of the water. This gives us a

constant flow of around 125,85 Kg/s.

Now that the mass has been calculated, the formula can be used for different

engine loads, as the specific heat consumption of water does not change and had

been set for 4,19 KJ/KgK. The different temperatures indicate the amount of waste

heat available in the HT water system.

9

4.2 Exhaust gas energy calculations In order to calculate the amount of heat used in the EGB’s, a couple variables have

to be found. These variables include the exhaust gas flow and the in – and outlet

temperatures of the exhaust gasses flowing through the EGB. The calculation is as

follows.

𝑄 = �̇� ∗ 𝑐 ∗ ∆𝑇

Q = The amount of energy stored in the exhaust gasses in KW

�̇� = The mass of the exhaust gas flow in Kg/s

c = The specific heat in KJ/KgK

ΔT = The difference in temperature of the exhaust gasses at the in - and outlet of the

EGB

The different temperatures were taken from the mimics of the EGB’s. These

accurately display the change in temperatures under different engine loads. The

specific heat for the exhaust gasses was chosen as 1,006 KJ/KgK.

To calculate the mass of air flow through the EGB, the engine fuel consumption and

air flow had to be determined. The amount of fuel burned was found using the Diesel

Engine Acceptance Test Records, found in appendix 2.

Unfortunately, the turbocharger attached to the DG is from a different manufacturer

than the DG itself. Therefore, no curves or graphs displaying the amount of air flowing

through the engines was found. So it had to be calculated. In order to do this, the

amount of air flowing through the engine at 21900 Turbo RPM’s was found in the

Diesel Engine Technical Data, found in appendix 3. Then, the amount of air was

divided by the amount of RPM’s, which showed the approximate amount of air per

turbocharger RPM. Although this is not completely accurate, as the charge air

pressure varies under different loads, this was the only available option. This issue is

explained further in chapter six. The calculation used is as follows.

�̇� = (�̇�

21900) ∗ 𝑛

�̇� = The flow of air in Kg/h

�̇� = The flow of air at 21900 RPM’s

𝑛 = The RPM’s of the turbocharger at a certain load

10

By multiplying the amount of air per RPM times the RPM’s of the turbocharger under

different loads, the amount of air flowing through the DG was found. The results of

these calculations can be found below, in table 1 and in figure 5.

(Table 1: Amount of air flowing through DG at different loads)

Engine Load RPM Amount of air (kg/s) Amount of air (kg/h)

80% 21900 22,51944444 81070

75% 20936,66667 21,5288631 77503,90715

73% 20406,66667 20,98387198 75541,93912

70% 20340 20,91531963 75295,15068

69% 20210 20,78164257 74813,91324

60% 19140 19,68137747 70852,9589

55% 18350 18,86903222 67928,51598

52% 17780 18,28290969 65818,47489

Figure 5: The amount of air flow under different engine loads

14

15

16

17

18

19

20

21

22

23

50% 55% 60% 65% 70% 75% 80%

Am

ou

nt

of

air (

kg

/s)

Engine load (%)

Amount of air per engine load (Kg/s)

11

4.3 Waste heat recovery baseline In order for the optimal engine configuration to be calculated, a baseline had to be

established. This baseline was found in the Steam Flow and Thermal Balance

diagram, found in appendix 4. This baseline serves as a guideline as to how much

recovered waste heat energy is used in full operation. It can therefore be used as a

reference when calculating the amount of heat recovered by the HT cooling water

and the EGB’s, compared to the amount of heat required to run at full operation.

The baseline shows the minimal required heat for certain heat recovery systems such

as Potable water HT heat recovery, A.C. HT heat recovery, Laundry service HT heat

recovery and HT heat evaporator recovery. The potable water, A.C., and laundry

service always requires a certain amount of heat when running a full operation. The

amount of heat left in the HT heat recovery is used to heat up the feedwater of the

evaporator. When the HT heat used for the evaporator is not enough, steam will be

used for the leftover required heat. This steam can be produced using the EGB’s or

using the auxiliary boiler.

The baseline also shows the steam consumption when running at full operation. The

amount of steam needed for the evaporator, the hotel users and the engine room

users is displayed. The engine room users consist mostly of tank, purifier and fuel

module heaters, whereas the hotel users consist mostly of galley, accommodation,

laundry and swimming pool heating.

For the purpose of this research, the amount of heat required was set for full

operation, with the average users requiring as follows;

- The fresh water production → 5146 kW per evaporator

- The potable HT heat recovery → 801 kW

- The A.C. HT heat recovery → 1530 kW

- The laundry HT heat recovery → 219 kW

- The heat consumption of the engine room and hotel users → 7000 kW

These numbers can be found in the Steam Flow and Thermal Balance sheet, found in

appendix 4, and the evaporator technical data sheet found in appendix 1.

12

4.4 Two engines configuration In order to find the optimal engine configuration, the amount of running engines had

to be considered. When sailing at cruising speed, the Nieuw Statendam sails on

either two, or three engines. The amount of waste heat recovered varies greatly

when sailing on two or three engines. So multiple configurations had to be

calculated. Firstly, a two engine configuration. The Nieuw Statendam always sails on

a shared load mode, meaning both engines are running with the same load.

When calculating the WHR of two engines, only one of the evaporators is running at

any given time. This is due to the fact that the evaporators were designed to run

using the waste heat of two engines, in order to meet the heat requirements of

running at full operation.

The data was gathered from two engines running at the following loads;

- 80% load

- 75% load

- 73% load

- 70% load

- 69% load

- 60% load

- 55% load

- 52% load

The data was put into Microsoft Excel, and by using the calculations found in chapter

4.1 and 4.2, the results displayed in Table 2 and Figure 6 were found.

(Table 2; Waste heat recovery per engine load)

Engine Load (%)

Heat in HT system (kW)

Heat in EGB's (kW)

Total WHR (kW)

80 6116,68 4191,09 10307,77

75 6011,22 3898,45 9909,66

73 5958,49 3419,78 9378,27

70 5483,92 3492,77 8976,69

69 4956,62 3261,39 8218,01

60 4429,32 2969,92 7399,24

55 2900,15 2961,23 5861,38

52 1845,55 2538,18 4383,73

13

Figure 6: Waste heat recovery of a two engine configuration

As seen in figure six, the amount of waste heat available drops significantly around

70%. This would indicate the most effective way of sailing on two engines would be

at 70% engine load or higher.

The results were compiled into the following tables.

(Table 3: Amount of HT heat used for services)

Potable recovery (kW) A.C. recovery (kW) Laundy recovery (kW) Evaporator recovery (kW)

801 1503 219 3593,68

801 1503 219 3488,22

801 1503 219 3435,49

801 1503 219 2960,92

801 1503 219 2433,62

801 1503 219 1906,32

801 1503 219 377,15

801 1503 219 0,00

(Table 4: Steam required for evaporator and engine room/hotel users)

As seen in table 4 and table 5, the amount of heat required for the evaporator to run

at full capacity cannot be supplied by the two engines running at low loads.

Therefore the evaporator will be shut off when the engines are running at low loads.

This has to be done in order to provide the laundry, potable water and A.C. recovery

system with the required amount of energy to run at full capacity.

1500,00

2500,00

3500,00

4500,00

5500,00

6500,00

7500,00

8500,00

9500,00

10500,00

0,52 0,57 0,62 0,67 0,72 0,77 0,82

WH

R e

ne

rgy (

kW

)

Engine Load %

Waste Heat Recovery

Heat in HT system Heat in EGB's Total WHR

14

The lower the engine loads, the more steam has to be produced by the oil fired

boiler. This is seen in table 5. With the evaporator shut off, a lot less energy will have to

be provided, but for the sake of this research, the evaporator is seen as always

running at full capacity.

The exact calculations for the two engine configuration can be found in appendix 5.

15

4.5 Three engines configuration When running on a three engine configuration, there are two important things to

consider. First, the amount of running evaporators. The evaporators of the Nieuw

Statendam require the heat of two engines running at high loads in order to run at

full capacity. Therefore, trying to run two evaporators on a three engine

configuration would mean either a high amount of heat supplied from the steam

system would be necessary, or the evaporators would not be producing their optimal

amount of distilled water. For the purpose of this research, only one evaporator will

be running at full capacity while the vessel is powered by three engines.

Secondly, the Nieuw Statendam is equipped with two Exhaust Gas Cleaning Systems,

or EGCS’s for short. This means that two out of three engines will be running on Heavy

Fuel Oil (HFO), and one engine will be running on Marine Gas Oil (MGO). The

different average caloric values of the fuels were set at 43140 KJ/Kg for HFO and

43700 KJ/Kg for MGO. These values were taken into consideration when calculating

the amount of waste heat recovered from the running engines.

The data of the three engine configuration was used in Microsoft Excel in the same

way as the two engine configuration data, whilst also running at the same loads. The

results of these calculations can be found in Table 6 and figure 3. All three engine

configuration calculations can be found in appendix 6.

(Table 5: Waste heat recovered with a three engine configuration)

Engine Load (%)

Heat in HT system (kW)

Heat in EGB's (kW)

Total WHR (kW)

80 9122,287597 6275,313428 15397,60103

75 8964,097639 5847,669795 14811,76743

73 8542,25775 5108,565601 13650,82335

70 8014,957889 5239,162077 13254,11997

69 7382,198056 5122,051444 12504,2495

60 6802,168208 4435,080325 11237,24853

55 4271,128875 4441,84566 8712,974535

52 2636,499306 3807,26968 6443,768985

16

Figure 7: Waste heat recovery of a three engine configuration

The results seen in figure seven are similar to those seen in figure six. The amount of

waste heat recovered sees a significant drop around 70%. This would mean the most

optimal way of sailing, considering the WHR system, is at 70% load or higher.

The results were compiled into the following tables.

(Table 6: Amount of HT heat used for services )

Potable recovery (kW) A.C. recovery (kW) Laundy recovery (kW) Evaporator recovery (kW)

801 1503 219 6599,29

801 1503 219 6441,10

801 1503 219 6019,26

801 1503 219 5491,96

801 1503 219 4859,20

801 1503 219 4279,17

801 1503 219 1748,13

801 1503 219 113,50

(Table 7: Steam needed for evaporator and engine room/hotel users)

As seen in table six, the amount of HT heat supplied by three running engines is more

than enough to supply heat to the potable water, A.C. and laundry recovery. At

higher loads, the three running engines also supply enough heat to run the

evaporator at full capacity. Below 70% load the engines stop supplying enough HT

heat for the evaporator and steam has to be used. The amount of steam produced

by the EGB’s drops significantly between 69% and 60%, suggesting the optimal load

for steam recovery lies at or above 69%.

2500

4500

6500

8500

10500

12500

14500

16500

52 57 62 67 72 77 82

Wa

ste

he

at

rec

ove

ry e

ne

rgy (

kW

)

Engine load (%)

Waste Heat Recovery

HT heat Heat EGB Total heat

17

5.0 Discussion

Evaporators

The Nieuw Statendam is equipped with two Wärtsilä type MSF 650/6 evaporators.

These evaporators were designed to run at full capacity requiring 5146 kW to

operate. This amount of energy could only be supplied by two engines running at

high loads, with extra steam being supplied by the EGB’s or auxiliary boilers. During

normal operations, the evaporator does not run at full capacity, supplying between

20 to 22 tons per hour. The Nieuw Statendam is also equipped with two reverse

osmosis plants, which are also able to produce potable water. Therefore, the

evaporators don’t need to run at full capacity. The evaporators are used to produce

distilled water and provide cooling for the DG’s, although this cooling can also be

provided by seawater heat exchangers. The results are based on the evaporator

needing 5146 kW of energy, although the amount of energy provided to the

evaporator is always less. For the sake of this research the maximum amount of

energy was used to provide clear results, but the amount of steam required to run

the evaporator will be less during actual normal operations.

Data collected using older data sheets

Unfortunately due to events relating to the COVID-19 outbreak, the Nieuw

Statendam did not sail according to schedule. Therefore, the data needed for this

research was acquired by looking at older data sheets. The older data sheets

contained most of the information necessary for this research, but was not actual

and therefore might not be as reliable as data gathered during normal operations.

The hotel and engine room users vary greatly during trips, as the vessel is not always

fully booked. The data collected from the older data sheets does not show the

amount of energy used by the engine room and hotel users. Assumptions needed to

be made concerning the hotel and engine room users which may cause some

unreliability.

Engines running at same loads

The engine configurations of the Nieuw Statendam are setup in such a way, that all

running engines share the same amount of load. If this was not the case, WHR might

be able to able to be regulated more carefully. Calculations for this research were

made under the impression of all engines running under the same load, the results of

this research would have been different if the different loads were applied to

different engines.

The flow of HT water

The amount of waste heat recovered for the HT system was based upon information

gather from appendix one. The HT pump connected to the engine, was supplied by

a different company that the engine manufacturer. Unfortunately, no pump

characteristics were found relating to the exact flow of the HT pump. Therefore the

results based on the flow found in appendix one, may differ from the actual results.

The difference is not very significant, when the results found in table two and table

five are compared to the results found in the baseline, found in appendix four.

18

The flow of the exhaust gasses

As previously discussed in chapter 4.2, the flow of the exhaust gasses was calculated

using the known flow at 21900 RPM’s and the actual RPM’s of the turbocharger.

However, the flow of air entering the engine is also affected by the ambient air

temperature, which varies from day to day, and by the charge air pressure. Because

the turbocharger was supplied by a company called ABB, and not the engine

manufacturer itself, no flow characteristics relating to charge air pressure were

found. This lead to the air flow being calculated by a self-constructed calculation,

which is not as accurate as an actual flow diagram. When compared to the

baseline found in appendix four, the difference in results are not large enough to be

unusable. The results would have been more reliable and accurate if the air flow

diagram was found.

19

6.0 Conclusion

6.1 Waste heat recovery conclusions In order to determine the optimal way of sailing with the main concern being the

amount of waste heat recovered, both in the form of heat found in the HT water,

and heat recovered from the exhaust gasses by the EGB’s, a look at the results found

in chapter 4.4 and 4.5 gives a clear answer. Below approximately 69 to 70% engine

load, the WHR system sees a significant drop. This means more energy can be

extracted from the WHR system when running at higher loads.

To answer the main question; Which engine load profile, considering the operation of

the entire plant, is the most fuel and cost effective? Both a two engine configuration

and a three engine configuration were calculated. The results were the same. Below

70% load, the drop in WHR is significant enough to conclude that the optimal load

profile would be at an engine load of 70% or higher.

6.2 recommendation It is recommended to sail at higher loads to gain the greatest benefits from the WHR

system. However, if sailing with multiple engines running at different loads would be

possible, this may need to be considered. Further investigation concerning the

optimal engine configurations and loads will have to be done in order to gain a

larger understanding of the subject. Some information, such as the exact amount of

HT water flowing through the system and the exact amount of exhaust gas flow

through the EGB was missing. Therefore, it is recommended to repeat this research

with the correct data, in order to validate the found results.

The calculations in this research are subjective to change, as the amount of heat

required to run the vessel at full capacity changes when sailing and when in port.

The amount of hotel and engine room users also varies from day to day. In order to

get the most reliable results, all engine room and hotel consumers would need to be

monitored separately and continuously.

20

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Behrendt, C. (2019). CONDITIONS OF WASTE HEAT RECOVERY IN MARINE WASTE HEAT.

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Francesco Baldi, C. G. (2014). A feasibility analysis of waste heat recovery systems for

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Koster, A. (2015). Dieselmotoren. Hoofdplaat: Adviesbureau de Koster.

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Quruvignesh. (2020, Januari). Operating faults in turbochargers. Opgehaald van

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Wartsila. (2020, Januari). Voyage and vessel efficiency. Opgehaald van Wartsila:

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Appendix 1: Fresh Water Generator Technical Data

22

Appendix 2: Diesel Engine Acceptance Test Records

23

Appendix 3: Exhaust Gas Data Diesel generator

24

Appendix 4: Steam Flow and Thermal Balance sheet

25

Appendix 5: Two engine configurations

Two engine configuration at 80% load

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Appendix 6: Three engine configuration Three engine configuration at 80% load

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Three engine configuration at 75% load

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The optimal load profile for the nieuw statendam

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