YMATES16 - Plimsoll 2021
Otto Vuorinen
ARRANGEMENT FOR
RECOVERING AND UTILIZING THE WASTE HEAT
GENERATED ONBOARD A
SHIP IN DISTRICT HEATING
2021 | Total number of pages 95
Otto Vuorinen
ARRANGEMENT FOR RECOVERING AND UTILIZING THE WASTE HEAT GENERATED ONBOARD A SHIP IN DISTRICT HEATING
The objective for this thesis was to study the feasibility of an idea behind a Finnish patent to utilize the waste heat generated onboard a ship by it’s engines and to use it in an onshore application to reduce the fuel consumption and the CO2 emissions of district heating in a port town. The thesis was set up to determine if commercially adequate amount of heat could be extracted from the waste streams of a ships engines, stored onboard and used onshore. Further the thesis aimed to determine if such waste heat production would make commercial sense as a conventional project.
Research method used was quantitative method for identifying recoverable waste heat energy content and to calculate the commercial feasibility of utilizing it in an onshore application as district heating energy source. One part of the study was to determine if it was achievable to heat the ballast mass adequately in a voyage timeframe onboard ships parting from Finnish seaports. The analysis part of the thesis studied energy pricing, CO2 emissions and the commercial feasibility of the system. One part of the study was also to draft the system description and PI configuration for the proposed waste heat recovery system. In the beginning of the study a mass of 1000mt of water was chosen as the basic set up for the calculations. This was estimated to be adequate for energy storing and yet practical for the port logistics for the ferries with fast turnaround in the ports. The study indicates that the suitable waste heat streams are available in way of cooling water and in way of exhaust gas. These streams allow the thermal medium to be heated to 98°C.
This temperature would put the waste heat in the valuable range for district heating.
The study was able to produce the answers for the research questions it was set out for. The study indicates that there are engine configurations available that would allow extracting adequate amount of waste heat energy, i.e. 61,68 MWh of heat in way of 1000m3 of water at 98°C temperature in ten hours sea voyage. This however is academic assumption and doesn’t reflect the technical features or operational profiles of the ships currently sailing from the Finnish seaports. Further the study indicates that even with less optimistic waste energy yields and moderate waste energy prices the system would be economically feasible way of producing district heating energy from waste heat generated at the sea.
The conclusion for the study is that the waste heat utilization system described in the patent could make a feasible way of producing district heating energy from waste heat in port towns. It would be one of the technologies to tap the waste heat sources in way of reducing the need for burning fuel for the district heating purposes. The largest gains would be when the district heating needs are low when one ship could supply large percentage of the daily consumption.
KEYWORDS:
Waste heat, Carbon neutrality, CO2 emission, District heating, Energy storage, Marine diesel engine, REDII
2021 | Sivumäärä 95
Otto Vuorinen
JÄRJESTELY LAIVALLA SYNTYVÄN HUKKALÄMMÖN TALTEENOTTAMISEKSI JA SEN KÄYTTÖ KAUKOLÄMMÖNTUOTANNOSSA
Opinnäytetyön tavoitteena oli selvittää suomalaissa patentissa kuvatun järjestelmän toteuttamiskelpoisuutta. Patentin idea on käyttää laivalla sen koneista syntyvää hukkalämpöä maissa. Pyrkimyksenä on vähentää polttoaineen kulutusta ja CO2 päästöjä satamakaupungin kaukolämmöntuotannossa. Opinnäytetyön lähtökohtana oli selvittää, onko aluksen koneiden hukkalämmön lähteistä mahdollista saada kaupallisesti riittävä määrä lämpöenergiaa, säilyttää se aluksella ja purkaa maihin hyötykäyttöä varten. Lisäksi selvitettiin, onko kyseinen hukkalämmöntuotanto kaupallisesti järkevää perinteisenä projektina.
Tutkimusmenetelmänä käytettiin kvantitatiivista menetelmää hyödynnettävän hukkalämmön energiasisällön määrittämiseksi ja kaupallisen toteuttamiskelpoisuuden laskemiseksi. Osa tutkimusta oli selvittää, onko Suomalaisesta satamasta lähtevällä laivalla mahdollista lämmittää vesimassaa riitävästi merimatkan aikana. Työn analyysiosassa tutkittiin energian hinnoittelua, CO2 päästöjä ja järjestelmän kaupallista toteuttamiskelpoisuutta. Osa työtä oli myös luonnostella järjestelmä kuvaus ja PI-kaavio esitetystä hukkalämmön hyödyntämisjärjestelmästä. Työn alussa valittiin laskennan lähtökohdaksi 1000 tonnia vettä. Tämän arvioitiin olevan riittävä energian varastoimiseen ja mahdollinen toteutettavaksi satamalogistiikan osalta lautta-aluksille, joiden kääntöaika satamissa on lyhyt. Tutkimus osoittaa, että laivalla on saatavilla soveltuvaa hukkalämpöä jäähdytysvedestä ja pakokaasuista. Näillä hukkalämmönlähteillä on välittäjäaine lämmitettävissä 98°C lämpötilaan. Tämä asettaa hukkalämmön arvokkaaseen luokkaan kaukolämmöntuotannossa.
Opinnäytetyössä onnistuttiin vastaamaan asetettuihin tutkimusongelmiin. Työ osoittaa, että on olemassa voimalaitoskonfiguraatioita, jotka mahdollistaisivat riittävän hukkalämmön tuoton, 61,68 MWh lämpöä sitoutuneena 1000m3 vettä 98°C lämpötilassa, kymmenen tunnin merimatkan aikana. Tämä on kuitenkin vain teoreettinen arvio, eikä suoraan viittaa minkään nykyisen Suomen satamiin seilaavan aluksen teknisiin ominaisuuksiin tai operointiprofiiliin. Tutkimus osoittaa lisäksi, että jopa hieman alemmalla energian saannolla ja maltillisemmilla energian hinnoilla järjestelmä olisi kaupallisesti toteuttamiskelpoinen tapa tuottaa kaukolämpöenergiaa merellä syntyvästä hukkalämmöstä.
Opinnäytetyön johtopäätös on, että patentissa kuvattu hukkalämmönhyödyntämismenetelmä saattaisi olla toteuttamiskelpoinen tapa tuottaa kaukolämpöenergiaa hukkalämmöstä satamakaupungeissa. Se olisi yksi hukkalämpöä hyödyntävistä menetelmistä vähentää polttoon perustuvan kaukolämmöntuotannon tarvetta. Merkittävimmät hyödyt syntyisivät tilanteissa, joissa kaukolämmön tarve on pieni, tällöin yksi laivakin voisi tuottaa merkittävän osan päivittäisestä kaukolämpöenergian tarpeesta.
ASIASANAT:
Hukkalämpö, CO2 päästöt, Energian varastointi, hiilineutraali, hukkaenergia, kaukolämpö, laiva diesel kone, RED II
LIST OF ABBREVIATIONS AND SYMBOLS 9
1 INTRODUCTION 6
1.1 Introduction of the research problem 6
1.2 Patent 6
1.3 Research question 8
1.4 Research method 8
1.4.1 Data analyzing target 8
1.4.2 Literature review 9
1.4.3 Method for data collection 10
2 SHIP HEAT RECOVERY ANALYSIS 12
2.1 System arrangement facilitating heat recovery onboard 12 2.2 Identifying probable waste heat reception counterparts in Finland for reference 13
2.3 Energy balance calculations 14
2.4 Estimations for recovered energy 14
2.4.1 Available energy for utilization 15
2.4.2 Selection of the engine and heat balance of diesel engine 16 2.4.3 Added plant efficiency to the total installed diesel system 27 2.4.4 Efficiency of the recovery and utilization system 29 2.5 Indications on recovery heat pricing and payback time estimation of the plant
onboard 33
2.6 Indications on energy and CO2 emission savings for the district heating operator 37
3 TECHNICAL PRINSIPLE OF THE SYSTEM 42
3.1 Operational functions of the system in Phase 1 loading cooled district heating water
onboard 46
3.2 Operational functions of the system in Phase 2 charging heat to district heating
water by waste heat onboard 47
3.3 Operational functions of the system in Phase 3 discharging heat laden district
heating water to shore heat accumulator 48
4 ONBOARD ENERGY RECOVERY SYSTEM DESCRIPTION 49
4.1 System onboard 49
4.4 System main losses 56
5 FEASIBILITY OF THE SYSTEM 57
5.1 Variables with effect to the feasibility of the system 58 5.2 Market for district heating energy in Helsinki and Turku 58
5.2.1 District heating utilization and the energy potential of ship borne waste heat 58
5.2.2 Carbon neutral future and CO2 reduction effect on the district heating
production 60
5.2.3 Changes in the market expectations in the CO2 emissions accepted for the
generation of district heating 61
5.3 Technical and operational feasibility of the system 62
5.3.1 Technical cost of the ships systems 62
5.3.2 Port operation cost 62
5.3.3 Onshore installation cost 63
5.4 Investment cost for the system 63
5.5 Investment calculations 65
5.5.1 Net Present Value – NPV 65
5.5.2 Net Present Value (NPV) conclusions 67
5.5.3 Internal Return Rate – IRR 67
5.5.4 Internal Return Rate (IRR) Method conclusions 69
5.5.5 Payback Period Method 70
5.5.6 Payback Period Method conclusions 71
5.6 Project feasibility check list 71
5.7 Possible hinders in the way of implementing waste heat recovery system 72 5.7.1 Investment category and required rate of return 72 5.7.2 Planned life cycle expectancy of the ship on the route planned for energy
recovery 73
5.7.3 Space allowance onboard 73
5.7.4 District heating system availability in the ships trading port and required
piping building costs 73
5.7.5 Technical compatibility problems 74
6 CONCLUSION 75
6.1.2 Research problem 77
6.2 Validity and reliability of the study 79
6.3 Development and action proposals for the Thesis principle 80
6.4 Further studies 80
REFERENCES 82
APPENDICES
Appendix 1. Steam generation potential from exhaust gases with different engine configurations
Appendix 2. Investment feasibility check list Appendix 3. Investment calculations
FIGURES
Figure 1 Daily revenue projected as function of the energy yield of the waste heat
recovery system. 34
Figure 2 District heating energy price in new real estates. Energia teollisuus -
kaukolämmön hinta 1.7.2020 (Energiateollisuus Ry, 2020) 34 Figure 3 District heating energy real price development. Energia teollisuus -
Kaukolämmön hinta 1.7.2020 (Energiateollisuus Ry, 2020) 35 Figure 4 District heating and heating production fuel price development. Index Jan 2004. Energia teollisuus - kaukolämmön hinta 1.7.2020 (Energiateollisuus Ry, 2020) 35 Figure 5 Daily revenue with price estimation 35% of energy price projected as function of the energy yield of the waste heat recovery system. 36 Figure 6 Annual revenue projected as function of the energy yield of the waste heat
recovery system. 37
Figure 7 Daily fuel cost savings comparing to DH production using coal 38
Figure 8 Daily CO2 reductions compared to coal usage 39
Figure 9 Annual fuel cost savings comparing to DH production using coal 40 Figure 10 Annual CO2 reductions compared to coal usage 40
EQUATIONS
Equation 1 Specific Heat Formula. 15
Equation 6 Flow type application steam consumption rate 24
Equation 7 Pump power demand 29
Equation 8 Pump motor power 30
Equation 9 for the energy efficiency of energy storing 31 Equation 10 Net Present Value (NPV) formula (Source
https://www.investopedia.com/terms/n/npv.asp) 66
Equation 11 Net Present Value (NPV) in easier way to remember (BERK, 2017) 66 Equation 12 Formula for Internal Rate of Return (IRR) calculation (FERNANDO, 2020)
68
PICTURES
Picture 1 Heat recovery arrangement in the patent (JURVANEN, 2012) 7 Picture 2 Waste heat recovery system principle illustrated in port of Helsinki. Waste heat is recovered during sea voyage and discharged for utilization in the city district
heating system during the port stay. 14
Picture 3 Sankey diagram of marine diesel engine; Source Pounder's Marine Diesel
Engines and Gas Turbines (WOODYARD, 2009) 17
Picture 4 Thesis Internal combustion engine powered power plant sankey diagram
(HUHTINEN, 2000) 28
Picture 5 Sankey diagram of a diesel engine CHP powerplant (Wärtsilä Energy, 2020) 28 Picture 6 District heating supply and return temperatures CHP plant (Wärtsilä Energy,
2019) 28
Picture 7 Energy recovery and storage Sankey diagram (KARA, 1987) 33 Picture 8 Ship energy use Sankey diagram, DNVGL (DINOPOULOS, 2014) 42 Picture 9 Typical heat balance of a marine Diesel engine 43 Picture 10 Diagram indicating the energy waste and utilization percentage 44 Picture 11 Diagram indicating the reduced wasted energy streams and increased
utilization rate of energy 44
Picture 12 System PI diagram 45
Picture 13 Schematic picture of diesel CHP system with the main (Wärtsilä Energy,
2019, pp. 4-5) 46
Picture 14 Phase 1 - Loading cooled district heating water onboard the ships energy recovery ballast tank no. 1 (thermal storage tank) is loaded with 1000m3 of DH water 46 Picture 15 Phase 2 - Charging heat to district heating water by waste heat onboard, the ship is in operation – Cooling water for ME is pumped from Energy recovery ballast tank no. 1 through ME HT heat exchanger and steam heating heat exchanger. Hot water is returned to Energy recovery ballast tank no. 2 at 98°C 47 Picture 16 Phase 3 - Discharging heat laden district heating water to shore, the heat accumulator Ships Energy recovery ballast tank no. 2 is discharged by 1000m3 of
heated district heating water at 98°C 48
Picture 17 Shipboard system PI diagram 49
Picture 18 Example diagram for multiple main engines (Wärtsilä. Marine Solutions,
2019, pp. 9-4). 51
Picture 21 Typical arrangement of steam heating system utilizing plate heat exchanger.
(Endress+Hauser, 2020) 53
Picture 22 Typical arrangement of steam heating system utilizing shell and tube heat
exchanger. (Endress+Hauser, 2020) 53
Picture 23 Onshore system PI diagram 54
Picture 24 Energy storage tank principle drawing (KARA, 1987, p. 48) 55
TABLES
Table 1 Heat balance of the selection of engines; Source Wärtsilä and MAN product guides available on the internet (Wärtsilä. Marine Solutions, 2019), (Wärtsilä. Marine
Solutions, 2019), (MAN Energy Solutions, 2010) 18
Table 2 Energy content available to be transferred to the District heating 19 Table 3 Time for energy transfer [h] matrix continues to next page 20
Table 4 Change in HT water temperature 21
Table 5 Steam generation potential from exhaust gases with different engine
configurations. Values are without Selective catalytic reactor (SCR) 23
Table 6 Selection of potential engines 26
Table 7 Fuel specific CO2-emission factors. Kivihiili = Coal (Source Motiva
Yhteenvetojen CO2-päästöjen laskentaohjeistus sekä käytettävät CO2-päästökertoimet
12/2012) (Motiva Oy, 2012) 41
Table 8 Potential ships for DH energy production and the percentage they could produce of the total district heating production of Helsinki and Turku (Energiateollisuus Ry, 2019), (Port of Helsinki, 2020), (Port of Turku, 2020) 59 Table 9 The assumed investment needs for onboard and onshore systems 64 Table 10 Cash flow present value using Present value factor of individual payments - Energy Yields 50% and 95% and 6%, 12% and 24% interest rates. 67 Table 11 IRR estimates of profitability of waste heat system with different energy yield
and prices 69
Table 12 Payback period for energy Yield 50% and 95% with different energy prices 71
Table 13 Investment feasibility check list 72
Abbreviation Explanation of abbreviation
c Specific heat (units J/kg∙K)
CHP Combined Heat and Power (power plant type)
𝐶0 Total initial investment costs
CO2 Carbon dioxide - a chemical compound
𝐶𝑡 Net cash inflow during the period 𝑡
DH District heating
DWT Deadweight tonnage, measure of a vessel's weight carrying capacity
g Gravitational constant 9.81 (m/s2)
GWh Giga watt hour
H Head
h Hour, 1h = 3600s
ℎ𝑓𝑔 Specific enthalpy of evaporation of steam (KJ/kg) HT High temperature (cooling water of a diesel engine)
𝑖 Discount rate or return that could be earned in alternative investments
IRR internal rate of return (Financial)
J Joules, 1J = 1Ws
kg Kilogram, base unit of mass
kgCO2/MWh Kilograms CO2 per MWh of energy
m Mass of a substance (kg)
m3 Cubic meter (volume)
𝑚̇ Mass flow of a substance (kg/s)
MCR Maximum Continuous Rating (of an engine)
ME Main (diesel) engine of the ship
MGO Marine gas oil (low sulphur fuel used onboard ships)
𝑚𝑆𝐹 Mass of secondary fluid (kg)
𝑚̇𝑆𝑇𝐸𝐴𝑀 Mean steam consumption rate (kg/s)
mt Metric ton, unit of mass
MWh Megawatt hour
NPV Net Present Value (Financial)
P1 Pump motor electrical power (W)
P2 Pump shaft power (W)
PI PI diagram - Piping and instrumentation diagram
Q Heat energy (Joules, J) – in Energy
q Heat transfer (kJ/s, kW)
Q Volumetric flow (m3/s) – in pumps 𝑄̇ Mean heat transfer rate (kW (kJ/s))
𝑅𝑡 Net cash inflow-outflows during a single period 𝑡
SCR Selective catalytic reactor
𝑡 Number or time periods
∆ Symbol meaning "the change in"
∆T Change in temperature - Temperature difference
€/a € - EURO’s (currency) per year
𝜂𝑚 Electric motor efficiency (%)
𝜂𝑝 Pump efficiency (%)
𝜂𝑠 Electric motor control efficiency (%)
K Degree on Kelvin scale (temperature), 1K = 1C
ρ Density, units typically (kg/m3)
1 INTRODUCTION
This thesis is about harnessing untapped waste energy source for use in a new way to be able to save resources and limit emissions in district heating in cities that have regular liner ship traffic and available district heating system in place for utilizing this new source of waste energy.
1.1 Introduction of the research problem
Research problem is the feasibility of the use of waste heat generated onboard a ship in an onshore application.
The problem is two folded: if it is technically feasible to extract and to store the adequate amount of waste heat from ships engines onboard in to a tank of water and if it is commercially feasible to utilize the stored energy in an onshore application.
The research problem is limited to the mentioned items and this thesis will not consider the capabilities of a ship nor to the problems arising from the ballast control of a ship operating a system described in this thesis. The ballast mass of 1000mt with density of 1000 kg/m3 is used for the convenience for two reasons: It is easily comprehendible and it is theoretically possible amount to be processed onboard and onshore in the assumed timeline of ferry shipping traffic. Also the mass of water needs to be sufficient for storing considerable amount of heat energy for the system ever to be considered feasible.
1.2 Patent
This thesis is based on Finnish patent FI 122804 B, (JURVANEN, 2012)
”Järjestely aluksen moottorin kehittämän hukkalämmön talteenottamiseksi”
Patent owner is the principal of the Thesis.
Basic principle of the system described in the patent is to utilize the excess heat generated by a diesel engine installed onboard a ship and to utilize the same energy in
an application onshore. The heat recovery arrangement in the patent is illustrated in the picture 1 below.
The idea of heat recovery is a hot topic as the energy production is moving towards coal neutral production methods hence it will be more attractive to implement methods to transfer waste heat to valuable utility energy source and thus eliminate the need for producing the same energy with fossil fuel. Utilization of waste heat instead of fossil fuel production will give the energy producing companies competitive advantage and goodwill among the customers and the communities.
Picture 1 Heat recovery arrangement in the patent (JURVANEN, 2012)
Heat recovery is made at sea from heat recovery units to fluid stored in ship tanks.
Recovered heat in fluid is transferred to heat recovery unit onshore to be utilized ashore.
Heat recovery unit may consist of tank and or heat exchanger unit.
1 ship operating at sea
2 engine (primary source for heat recovered 3 exhaust gas heat exchanger
4 & 5 pumps
6 & 7 heat exchangers (primary / secondary fluid)
8 tank with fluid used for storing recovered heat (energy storage onboard) 9 reception facility onshore (energy storage onshore)
10 transportable tank holding heated medium (not applicable in this study) 11 heat exchanger unit onshore utilizing the heated medium
12 heat exchanger in the shore tank utilizing the heated medium
1.3 Research question
What is the recoverable waste heat energy content and the processing method for diesel engine generated waste heat energy conserved to thermal storage tank onboard in passenger traffic from and to Helsinki and Turku.
1.4 Research method
Research method used is quantitative method for identifying recoverable waste heat energy content and to calculate the commercial feasibility of utilizing it in an onshore application as district heating energy source.
One part of the study is to determine if it is achievable to heat the ballast mass with adequate ∆T in voyage timeframe.
The analysis part of the thesis will study energy pricing, CO2 emissions and the commercial feasibility of the system.
1.4.1 Data analyzing target
1) Analyzing the heat energy available on two way route from Finland to Sweden.
Aim is to identify engine combination that will provide adequate amount of waste
heat to heat 1000m3 of water to a sufficient temperature (98C) allowing feasible heat source for district heating.
2) Analyzing potential traffic density in Finnish ports to identify potential users for the waste heat source. Further to identify if there are any low hanging fruits in this field that are more prepared for implementing such energy source.
3) Analyzing the financial feasibility of such system by analyzing the energy prices in district heating and by analyzing the amount of fuel saved by the use of waste heat from ships in potential harbor town.
4) Analyzing the CO2 saving potential provided by the use of waste heat from ships in potential harbor town.
1.4.2 Literature review
Literature review for this thesis was done for identifying if such subject was already been studied and what were the results of such studies if found. Further literature was reviewed to identify potential reference literature, research papers, publications and thesis work. These were supplemented by the review of reference literature in the fields relevant to the scope the thesis.
The initial review revealed that the subject scope was unique. The combination of energy recovery onboard with onboard storing of energy and the utilization of the same outside the ship had not been studied. Parts of the scope have been studied independently.
Search for district heating heat energy storing brings up several publications and number of studies and thesis work (Motiva; HEIKKILÄ, I. and KIURU, T, 2017), (Motiva Oy;
HEIKKILÄ, I., KIURU, T., 2014) , (RAATIKAINEN, 2015), (VTT; RÄMÄ, M. and KLOBUT, K., 2020), (PORKKA, 2013), (ESTERINEN, 2019), (KORPELA, 2018), (KONG, 2014), (LEE, 2013) (LIU, 2014), (MAKARTCHOUK, 2002), (WOODYARD, 2009), (THARMARATNAM, 2018), (TURUNEN, 2019), (VILKKILÄ, 2019), (WALLIN, 2014), (ZOLKOWSKI, 2009), (Pöyry Oy; MUUKKONEN, H., 2014) These publications and studies provide insight that that energy storing is well established technology and that the feasibility of such systems is dependent on the energy price and the scale of the storage facility (KARA, 1987), (Gaia Consulting Oy; BRÖCKL, M., IMMONEN, I., VANHANEN, J., 2014), (KOIVUNIEMI, 2014), (SENTHILKUMAR, 2016). It may also be noted that energy storing is far from new idea. The references that are still useful are dating back many decades.
Energy recovery from marine diesel engines is common place and references to this is found in every engine manufacturers project guides (Wärtsilä. Marine Solutions, 2019), (Wärtsilä. Marine Solutions, 2019), (Wärtsilä. Marine Solutions, 2018), (MAN Energy Solutions, 2019), (MAN Energy Solutions, 2010) and from boiler manufacturers project guides (Global maritime energy efficiency partnerships, 2020), (Alfa Laval Corporate AB, 2020), (Alfa Laval Nordic Oy, 2020) . Hardest part of the literature review was searching reference material for research papers made for studying the possibilities of heating large mass of water onboard using the diesel engine waste heat. Few were found (BALAJI, 2012), (BALAJI, 2017), (CHINNAPANDIANA, 2011). The most important and most closely parallel studies were the analysis of shipboard waste heat availability for ballast water treatment, by R. Balaji & O. Yaakob, Journal of Marine Engineering & Technology, 11:2, 15-29 01.12.2014, and the experimental investigation of storing engine waste heat using phase change material in Experimental Investigation of Cascaded Latent Heat Storage System for Diesel Engine Waste Heat Recovery by M. Chinnapandian. General utilization of waste heat were more easily available but research on the time and heat needed for the required ∆T were hard to come by. For this I concluded that that this needs to be studied in this thesis.
The feasibility study required to review the subject matter with wider scope. Energy pricing and emission data were available in form of reports, presentations and analysis mostly made by the research organisations linked to district heating (VTT; RÄMÄ, M.
and KLOBUT, K., 2020) (Energiateollisuus ry, 2020), (Helen Oy, 2019), (Motiva Oy, 2012). These papers and presentations were great source for emission data and for gaining the idea on the district heating energy pricing levels in effect at the time of the reports. The open source data available on the Helen website (Helen Oy, 2016) provides valuable insight of the variable nature of the district heating energy during different seasons and times of the day.
The feasibility study also demanded the review of the investment finance reference material. Such material was available in the field of economics and reference is made to some good reference books when the feasibility of an investment is discussed.
1.4.3 Method for data collection
Most of the data used in the analyses for the potential waste heat energy available in
Calculus is done using equations that are very well established in the field of marine engineering and can be found in many reference and text books of the subject matter (HÄKKINEN, 1993), (WOODYARD, 2009), (HUHTINEN, 2000) and physics (YOUNG, 1996), (HÄNNINEN, 2001).
District heating system water temperatures and prices for the energy have been obtained from internet. Data has been collected from the websites of well-known district heating providers, energy expert entities and official statistics in Finland. CO2 emission information is obtained from Motiva provided CO2 calculation method brochures for district heating applications that are available on the internet (Helen Oy, 2016), (Energiateollisuus Ry, 2020), (Vantaan Energia Oy, 2020), (Energiateollisuus Ry, 2019), (Energiateollisuus Ry, 2020).
2 SHIP HEAT RECOVERY ANALYSIS
2.1 System arrangement facilitating heat recovery onboard
Reference material provides little references to marine heat recovery applications where the heat recovered from the diesel engines is used for other purposes than using the energy onboard the ship in way of heat for domestic services, ballast water treatment, deck heating or generating electricity. Studies and literature references were available regarding storing heat energy to water in heat accumulators or thermal storage tanks in district heating systems. These were all for shore applications however. Thermal storage tank technology is well established method for storing energy in district heating systems utilizing available energy to heat the stored water when the district heating demand is low and to use the energy when the demand is high in peak shaving configuration.
It is easy to find applicable arrangement for harvesting the waste heat onboard however.
These systems have been in place for as long as ships have been using engine power.
The high temperature water (HT-water) has been used for heating different consumers onboard. The exhaust gas stream has been used to produce steam in way of economizers. Both applications for harvesting the primary waste heat are readily available in the project catalogues of the engine and boiler manufacturers. The same are used in the system described in this thesis.
The system set up for land based applications where diesel engine(s) are used for prime movers for combined heat and power (CHP) generation even with thermal storages is common place and may be found from the project manuals of diesel makers. The major system difference in this thesis is that the system is storing energy first onboard and then transferring the mass of heat energy enriched water to the shore for utilization comparing to using the waste heat locally near a shore power plant.
These references give strong support for the idea that such shipboard CHP power plant with thermal storages is technologically possible to be built and operated using existing technologies and operating models of marine engineering and district heating systems.
Full system PI diagram is show in picture 12 in chapter 3 Technical principle of the system in the patent. Picture 2 below illustrates principle of the total system using two 1000m3 tanks in the onboard system and also on two 1000m3 tanks in the shore side
system. One for energy enriched hot water and one for cooler return water. These are to provide minimum change in the ships weight in the water and to isolate the heat enriched district heating (DH) water and the cooler return DH water in different tanks.
2.2 Identifying probable waste heat reception counterparts in Finland for reference
Quick study to ship operation database data available on the internet (TallinkSilja, 2020), (Viking line, 2020), (Port of Turku, 2020), (Port of Helsinki, 2020) indicates the ports that have liner traffic going through the port. Out of this data it is possible to identify the ports where district heating facilities are presently available in the ports or in close proximity of the same. This way a list of potential ports has been drawn up. List promotes two strong candidates: Helsinki and Turku. Other candidates could be Kotka, Rauma and Vaasa.
These ports and ships are only identified in this study due to the fact that they both have district heating system in vicinity of the liner ports and that the ships operating from those ports have adequate installed main engine power onboard to be able to heat 1000mt of water as is the scope of this thesis. This thesis does not take to consideration any of these existing ships technical capabilities for harvesting the waste heat nor if the ships are capable of carrying and perform the port operations of the 1000mt ballast water mass however.
Picture 2 Waste heat recovery system principle illustrated in port of Helsinki. Waste heat is recovered during sea voyage and discharged for utilization in the city district heating system during the port stay.
2.3 Energy balance calculations
This study is restricted to make a hypothetical case, however rough estimate is drawn to allow for an idea of heat energy available from liner traffic in some of the busiest ports in Finland.
Calculus is based on that the Main engine power and generated waste heat respectively is adequate to heat 1000m3 of water onboard the ship(s) on the round trip that the ship(s) operating from the said port execute annually.
2.4 Estimations for recovered energy
The calculus will provide with the amount of energy one ship may provide on a round trip in MWh’s, the amount of energy the system of ships operating from the said port may provide annually in GWh’s and the percentage that energy would provide from the cities
Study is focused on Turku and Helsinki as both cities have district heating piping readily available in proximity of the liner port facilities.
2.4.1 Available energy for utilization
The amount of energy estimated to be transferable is based on assumption that a volume of 2000m3 is available for water ballast to be utilized for energy recovery. This will allow 1000 metric tons of water to be energy enriched with the heat energy recovered from the diesel engines onboard. Second assumption is that the water is heated to 98C as a maximum temperature for the water to avoid boiling and subsequent pressure built up in the ballast tanks.
Hence the amount of energy to be recovered and utilized onshore will be the heat energy stored to 1000 tons of water at 98C. District heating water temperature in the return pipe usually varies between 40C and 60C (Energiateollisuus Ry, 2020) in this study 45C return water temperature has been used and total system ∆T 53C respectively.
It is assumed that the energy shall be recovered during a single voyage on liner traffic between Turku – Stocholm – Turku with total sea voyage length of 20 hours. (Viking line, 2020) (TallinkSilja, 2020). This route has been taken as the basic route as it is the shortest, hence the most challenging for the system to accumulate adequate energy in the given sailing time.
The basic question is how much heat energy may be recovered onboard and transferred to shore for utilization? To answer this we use the
Equation 1 Specific Heat Formula.
𝑸 = 𝒎𝒄∆𝑻 (1)
Q = heat energy (Joules, J) m = mass of a substance (kg) c = specific heat (units J/kg∙K) ρ = density, units typically (kg/m3)
∆ is a symbol meaning "the change in"
∆T = change in temperature (Kelvins, K)
District heating return water temperature fluctuates between 40 - 60C. It is assumed to be 45C. District heating water is returned to shore in 98C.
Specific heat capacity c of water = 4190 J/kg*K.
1K = 1C 1J = 1Ws 1h = 3600s ρ = 1000kg/m3
Heat energy in 1000m3 of DH water when temperature is raised with 53C is 222070MJ or in other way 61,68 MWh
2.4.2 Selection of the engine and heat balance of diesel engine
Sankey diagram of typical marine diesel engine energy balance shows the fact that even the Diesel engine is fuel efficient in way of internal combustion engines it still has remarkable losses. These losses are heat that escapes from utilization mainly to exhaust gases and to cooling water. Sankey diagram of marine diesel engine is shown in picture 3.
Picture 3 Sankey diagram of marine diesel engine; Source Pounder's Marine Diesel Engines and Gas Turbines (WOODYARD, 2009)
It is assumed that the most simple and cost effective mechanism to recover energy from the diesel engine system at adequate temperature is to utilize the excess heat from the diesel engine high temperature (HT) cooling system and from the exhaust gas system in way of an exhaust gas economizer. These systems allow the energy to be recovered at appropriate temperature directly from the systems without additional heat energy to be added to the equation. Both energy recovery methods are commonplace and technologies are widely available.
Table 1 Heat balance of the selection of engines; Source Wärtsilä and MAN product guides available on the internet (Wärtsilä. Marine Solutions, 2019), (Wärtsilä. Marine Solutions, 2019), (MAN Energy Solutions, 2010)
Heat balance [kW]
Wärtsilä W8V31
Wärtsilä W12V31
Wärtsilä W14V31
MAN L32/40 9cyl
MAN V32/40 14cyl
MAN V32/40 16cyl
Wärtsilä W8L50DF gas
Wärtsilä W8L50DF oil Generator set
power, kW 4880 7320 8540 4500 7000 8000 7600 7600
Jacket water,
HT-circuit 494 742 865 699 971 1110 872 1304
Charge air,
HT-circuit 926 1388 1620 1214 1640 1900 1040 1632
Charge air, LT-
circuit 1230 1844 2152 639 855 1002 576 864
Lubrication
oil, LT-circuit 522 784 914 587 982 1122 616 976
Total heat
balance kW 3172 4758 5551 3139 4448 5134 3104 4776
Total heat
MJ/h 11419,2 17128,8 19983,6 11300,4 16012,8 18482,4 11174,4 17193,6 Total heat to
HT water, kW 1420 2130 2485 1913 2611 3010 1912 2936
Heat to HT
water MJ/h 5112 7668 8946 6886,8 9399,6 10836 6883,2 10569,6
Number of
gen sets 2
Total heat
balance kW 6344 9516 11102 6278 8896 10268 6208 9552
Total heat
MJ/h 22838,4 34257,6 39967,2 22600,8 32025,6 36964,8 22348,8 34387,2 Total heat to
HT water, kW 2840 4260 4970 3826 5222 6020 3824 5872
Heat to HT
water MJ/h 10224 15336 17892 13773,6 18799,2 21672 13766,4 21139,2
Number of
gen sets 3
Total heat
balance kW 9516 14274 16653 9417 13344 15402 9312 14328
Total heat
MJ/h 34257,6 51386,4 59950,8 33901,2 48038,4 55447,2 33523,2 51580,8 Total heat to
HT water, kW 4260 6390 7455 5739 7833 9030 5736 8808
Heat to HT
water MJ/h 15336 23004 26838 20660,4 28198,8 32508 20649,6 31708,8
Number of
gen sets 4
Total heat
balance kW 12688 19032 22204 12556 17792 20536 12416 19104 Total heat
MJ/h 45676,8 68515,2 79934,4 45201,6 64051,2 73929,6 44697,6 68774,4 Total heat to
HT water, kW 5680 8520 9940 7652 10444 12040 7648 11744 Heat to HT
Engine selection for the study began with survey of the power range and types of engines in use on the ferry ships operating in liner traffic from Finnish ports. Main type of the engines are medium speed four stroke turbocharged diesel engines. Usual configuration is a multi-engine installation turning generators or shaft lines via transmission. Existing engine makers and selection was studied and few examples were compared in way of finding the engine type to be used as an example In this study. For the sake of comparability all the engine sets are assumed to be diesel generator sets that allow power management. The engine heat balances were compared to each other focusing on two main characteristics, namely: heat to HT water and exhaust gas mass flow and temperature after turbo charger.
The heat balances for the selection of engines shows that there is considerable source of heat energy available in the HT water. The heat is in the right temperature range i.e.
85°C – 98 °C and makes it good source of waste heat. The next step is to refine the selection in way of identifying the most suitable engine for this study. This was done by checking what engines would emit enough waste heat to HT water during 10 hours allowing adequate ∆T for the application. The adequate ∆T was tested for the whole
∆T=53°C and for more practicable ∆T=10°C. Lower ∆T allows the most simple heat exchanging arrangement for the engine cooling.
Table 2 Energy content available to be transferred to the District heating
1000 m3 DH water
4190J/kgC
Q=cm Temperature raise and needed heat
45-55C 45-98C
T T=10C T=53C
Q= 41900000000 2,2207E+11
Q [MJ] 41900 222070
Q[MWh] 11,639 61,686
The time for the energy transfer was studied for different arrangement of engine sets in use. It shows that reaching the ∆T=10°C for the district heating water is easily available, even the high ∆T=53°C seems attainable for some engine configurations. The Table 3 shows that all the engine arrangements allow for the lower ∆T=10°C even with only one
engine in use and that the more high power engine configurations seem to allow for the higher ∆T=53°C when running three or four units in parallel.
Table 3 Time for energy transfer [h] matrix continues to next page
Time for energy transfer [h]
Number of gensets
T=10C (45-55C)
T=53C (45-98C)
W8V31 - 4880kW h h
1 8,20 43,44
2 4,10 21,72
3 2,73 14,48
4 2,05 10,86
W12V31 - 7320kW
1 5,46 28,96
2 2,73 14,48
3 1,82 9,65
4 1,37 7,24
W14V31 - 8540kW
1 4,68 24,82
2 2,34 12,41
3 1,56 8,27
4 1,17 6,21
Time for energy transfer [h]
Number of gensets
T=10C (45-55C)
T=53C (45-98C)
MAN L32/40 9cyl - 4500kW h h
1 6,08 32,25
2 3,04 16,12
3 2,03 10,75
4 1,52 8,06
MAN V32/40 14cyl - 7000kW
1 4,46 23,63
2 2,23 11,81
3 1,49 7,88
4 1,11 5,91
MAN V32/40 16cyl - 8000kW
1 3,87 20,49
2 1,93 10,25
3 1,29 6,83
4 0,97 5,12
Time for energy transfer [h]
Number of gensets
T=10C (45-55C)
T=53C (45-98C)
W8L50DF gas - 7600kW
1 6,09 32,26
2 3,04 16,13
3 2,03 10,75
4 1,52 8,07
W8L50DF diesel - 7600kW
1 3,96 21,01
2 1,98 10,51
3 1,32 7,00
4 0,99 5,25
Matrix indicates the time energy transfer of needed heat will take with different engine configurations.
Green indicates the heat transfer is obtainable in ten hours or less, engines running on 100% load.
It would be too easy to conclude that adequate amount of waste heat would be available easily by tapping in the HT cooling system of multi-engine installation available on the ships. Unfortunately that is not the case, one needs to consider the cooling pump capacity of the engines also to realize that the temperature change in conventional cooling arrangement of the ships is considerably lower than the required ∆T=53°C. This is due to the pumping capacity of the HT water, the greater capacity the lower Change in temperature ∆T °C is available with conventional arrangements.
Table 4 Change in HT water temperature
Heat balance [kW]
Wärtsilä W8V31
Wärtsilä W12V31
Wärtsilä W14V31
MAN L32/40 9cyl
MAN V32/40 14cyl
MAN V32/40 16cyl
Wärtsilä W8L50DF gas
Wärtsilä W8L50DF oil
Generator set power, kW 4880 7320 8540 4500 7000 8000 7600 7600
Jacket water, HT-circuit 494 742 865 699 971 1110 872 1304
Charge air, HT-circuit 926 1388 1620 1214 1640 1900 1040 1632
Charge air, LT-circuit 1230 1844 2152 639 855 1002 576 864
Lubrication oil, LT-circuit 522 784 914 587 982 1122 616 976
Total heat balance kW 3172 4758 5551 3139 4448 5134 3104 4776
Total heat MJ/h 11419,2 17128,8 19983,6 11300,4 16012,8 18482,4 11174,4 17193,6
Total heat to HT water, kW 1420 2130 2485 1913 2611 3010 1912 2936
Heat to HT water MJ/h 5112 7668 8946 6886,8 9399,6 10836 6883,2 10569,6
HT cooling pump capacity M3/h 96 110 130 54 84 96 180 180
Change in HT water temperature ∆T °C 12,7 16,6 16,4 30,4 26,7 26,9 9,1 14,0
Heat available from HT system
The change in temperature of the HT water in above table is calculated with the basic formula.
Equation 2 Change in temperature
∆𝑻𝑯𝑻= 𝑸
𝒄𝒎 (2)
Q = heat energy (Joules, J) m = mass of a substance (kg) c = specific heat (units J/kg∙K)
∆ is a symbol meaning "the change in"
∆T = change in temperature (Kelvins, K)
Specific heat capacity c of water = 4190 J/kg*K.
The change in temperature indicates that different engine type have different characteristics that shall be taken to account when choosing the engine types for a new building. For the sake of this study, temperature change of 10°C is chosen. This low
∆THT=10°C is easily comprehendible and allows that the most rigorous performance demand for the exhaust gas heat recovery is set in the study. With low ∆THT=10°C the rest from the total ∆TTOT=53°C is left to be achieved from the waste heat in the exhaust gases. The ∆T for the exhaust gas recovery is ∆TEXH=43°C. This energy is extracted from the exhaust gases in way of exhaust gas economized. This technology is common place in the marine engineering and is widely used onboard ships.
First the available power in kW in the exhaust gas must be calculated using Equation 3 Heat transfer
𝒒 = 𝒎̇𝒄∆𝑻 (3)
q = heat transfer (kJ/s, kW)
𝑚̇ = mass flow of a substance (kg/s) c = specific heat (units J/kg∙K)
∆ is a symbol meaning "the change in"
∆T = change in temperature (Kelvins, K)
Specific heat capacity c of Exhaust gases = 1050 J/kg*K
Mass flow of the exhaust gases is available in the engine product guides in kg/s. As on kJ/s equals kW the equation result is in kW. After that a rule of thumb factor of 1,5 is used for steam production estimation in kg/h for marine waste heat recovery boiler applications. The rule of thumb factor and specific heat capacity value of 1050 J/kg*K allows for approximately 3% losses.
Equation 4 Rule of thumb for steam production
𝒎̇𝑺𝑻𝑬𝑨𝑴= 𝟏, 𝟓 ∗ 𝒒 (4)
Table 5 Steam generation potential from exhaust gases with different engine configurations. Values are without Selective catalytic reactor (SCR)
Steam generation potential from exhaust gases
Wärtsilä W8V31
Wärtsilä W12V31
Wärtsilä W14V31
MAN L32/40 9cyl
MAN V32/40 14cyl
MAN V32/40 16cyl
Wärtsilä W8L50DF gas
Wärtsilä W8L50DF oil
Generator set power, kW 4880 7320 8540 4500 7000 8000 7600 7600
Exhaustgas systems
Flow at 100% kg/s 8,7 13,3 15,3 8,7 13,5 15,4 11,9 15,1
Flow at 100% t/h 31,4 48,0 54,9 31,3 48,6 55,5 42,8 54,4
Temperature after TC at 100% 285,0 273,0 285,0 365,0 364,0 364,0 401,0 337,0
Temperature after Economizer (saturated
steam temperature at 7barG) 170,0 170,0 170,0 170,0 170,0 170,0 170,0 170,0
Heat content kW 1052,9 1440,6 1842,6 1780,2 2750,0 3140,4 2886,3 2647,8
Total heat MJ/h 3790,6 5186,0 6633,5 6408,7 9899,8 11305,4 10390,8 9532,0
Steam kg/h (rule of thumb) 1579,4 2160,8 2764,0 2670,3 4124,9 4710,6 4329,5 3971,7
Total Steam generation kg/h
Number of gen sets 1 1579,4 2160,8 2764,0 2670,3 4124,9 4710,6 4329,5 3971,7
Number of gen sets 2 3158,8 4321,7 5527,9 5340,6 8249,9 9421,1 8659,0 7943,4
Number of gen sets 3 4738,2 6482,5 8291,9 8010,8 12374,8 14131,7 12988,6 11915,0
Number of gen sets 4 6317,6 8643,3 11055,9 10681,1 16499,7 18842,3 17318,1 15886,7
= C ( − C) Heating the mass using 6 bar (gauge) saturated dry steam
= C ( − C) Heating the mass using 6 bar (gauge) saturated dry steam
= C ( − C) Continuous heating using 6 bar (gauge) saturated dry steam
= C ( − C) Continuous heating using 6 bar (gauge) saturated dry steam
Once the available steam production has been estimated it is the time to use steam consumption calculations in order to identify the feasibility of the system. In the feasibility estimation it is assumed that ∆TTOT=53°C is required to achieve the 98°C discharge temperature for the district heating water, further it is assumed that low ∆THT=10°C is recovered from the HT water leading to a need for additional ∆T=43°C to be transported to the water using steam heating. In this study two applications have been studied, the non-flow type application where the product to be heated is a fixed mass and a single batch within the confines of a vessel. The other application is the flow type application where heated fluid (DH water) constantly flows over the heated transfer surface (SpiraxSarco, 2020).
Equation 5 Non-flow type application steam consumption mean heat transfer rate 𝒎̇𝑺𝑻𝑬𝑨𝑴 ∗ 𝒉𝒇𝒈= 𝑸̇ =̇ 𝒎𝑺𝑭∗𝒄∗∆𝑻𝒕 (5)
𝑄̇ = Mean heat transfer rate (kW (kJ/s)) 𝑚𝑆𝐹 = Mass of secondary fluid (kg)
c = Specific heat capacity of the secondary fluid
∆T = Temperature raise of the secondary fluid t = Time for heating process (seconds) 𝑚̇𝑆𝑇𝐸𝐴𝑀 = Mean steam consumption rate (kg/s)
ℎ𝑓𝑔 = Specific enthalpy of evaporation of steam (KJ/kg)
Non-flow type application steam consumption is 7714kg/h 6bar gauge saturated steam for heating secondary fluid mass of 1000mt with ∆T of 43ºC.
Equation 6 Flow type application steam consumption rate 𝒎̇𝑺𝑻𝑬𝑨𝑴 =𝒎𝑭𝑹∗𝒄∗∆𝑻
𝒉𝒇𝒈 (6)
𝑚̇𝑆𝑇𝐸𝐴𝑀 = Mean steam consumption rate (kg/s) 𝑚𝐹𝑅 = Mean flow rate of secondary fluid (kg/s) c = Specific heat capacity of the secondary fluid
∆T = Temperature raise of the secondary fluid t = Time for heating process (seconds)
ℎ𝑓𝑔 = Specific enthalpy of evaporation of steam (KJ/kg)
𝑚̇𝑆𝑇𝐸𝐴𝑀 = 10028𝑘𝑔 ℎ
Flow type application steam consumption is 10028kg/h 6bar gauge saturated steam secondary fluid mean flow rate of 36,1kg/s (130m3/h).
The calculations provide with criteria that needs to be implemented in the selection of the engines in a ship and in this study it provides with the criteria that allows the answer for the research question – it is feasible to collect adequate waste heat energy from the ships engine on 10 hour timeline to heat a 1000 ton mass of water by 53°C. The feasibility is depending on number of features in the machinery arrangement and in the possible arrangement of the heat recovery system. The main variables effecting the results in the machinery arrangement and the engines are the engine cooling system capability to provide as high ∆T from HT water as possible and the exhaust gas waste heat recovery boiler capability to provide as high steam production as possible. In a new building ship the selection of engines may be considered to optimize these features, namely:
HT water pump capacity – the lower capacity the higher ∆T
Implementing multi stage heat exchangers to HT water allowing the secondary fluid to have higher ∆T
Selecting engine with high temperature after turbo charger to provide high ∆T for the waste heat recovery boiler.
Optimizing the waste heat recovery boiler
For this study the main question remains if there is adequate potential for waste heat recovery for 1000m3 of district heating water on ten hour sailing pattern. For this to be
used as indication for what engine types may prove potential, the above calculations are used to identify what engine type from the selection would be capable of recovering the heat adequately. The results are visible in the Table 6 below.
Table 6 Selection of potential engines
Adequate potential for waste heat recovery for 1000m3 of district heating water
Wärtsilä W8V31
Wärtsilä W12V31
Wärtsilä W14V31
MAN L32/40 9cyl
MAN V32/40 14cyl
MAN V32/40 16cyl
Wärtsilä W8L50DF gas
Wärtsilä W8L50DF oil
Generator set power, kW 4880 7320 8540 4500 7000 8000 7600 7600
Total heat to HT water, kW per unit 1420,0 2130,0 2485,0 1913,0 2611,0 3010,0 1912,0 2936,0 Exhaust gas Heat content kW per unit 1052,9 1440,6 1842,6 1780,2 2750,0 3140,4 2886,3 2647,8 Steam kg/h (rule of thumb) per unit 1579,4 2160,8 2764,0 2670,3 4124,9 4710,6 4329,5 3971,7
Number of gen sets 1
Number of gen sets 2
Number of gen sets 3
Number of gen sets 4
No potential
Potential in non-flow type steam heating if higher HT water ∆T is attainable Potential in non-flow type steam heating
Potential in flow type steam heating if higher HT water ∆T is attainable Potential in flow type steam heating
For the criteria in the calculations the most rigorous option has been chosen in way to prevent the estimations to be too optimistic. Examples of these selections are that the low ∆THT=10°C is assumed to be recovered from the HT water. This was due to choosing the largest volume HT pump capacity from the engine selection. This left the rest of ∆TTOT=53°C to be recovered from the exhaust gases. This led to the finding that even the engines have similar total power ratings they, due to the efficiency of the engine, may not allow as much waste heat to be recovered. From the Table 6 above it is possible to find that the potential for the waste heat recovery needed to satisfy the research question are engine configurations with 3 – 4 engine units of 7000 – 8000kW Maximum continuous output and above 337°C exhaust gas temperature after turbocharger.
From that it is possible to note that existing ships with installed engine power ranging above 21000kW may be potential waste heat producers for district heating purposes.
2.4.3 Added plant efficiency to the total installed diesel system
Assuming the engine consumption doesn’t increase due to utilization of it’s waste streams an additional efficiency may be calculated by dividing the consumption with the added energy utilization from the waste heat pumped to the shore reduced by the energy needed for its harvesting, losses during the process and storing and the energy needed for moving the mass of water between the ship and shore.
The total system may be referenced to a diesel engine powered Combined Heat and Power plant. This type of plants are available from diesel engine manufacturers project portfolios. The project manuals for such plants indicate high total efficiency for such plants as may be seen on the Picture 4 below. The major difference between these plants is the fact that on a shipboard waste heat recovery plant the waste heat is stored onboard to tanks and pumped to shore for utilization and on pure CHP plant the district heating water is used for straight cooling purposes.
Picture 5 is showing the sankey diagram an Internal combustion engine powered power plant and it’s energy and waste streams. Picture 6 from Wärtsilä project guide (Wärtsilä Energy, 2020) indicates that the plant fuel efficiency rate may be raised by 46% when the waste heat is utilized instead of pure engine shaft power.
Picture 4 Thesis Internal combustion engine powered power plant sankey diagram (HUHTINEN, 2000)
Picture 5 Sankey diagram of a diesel engine CHP powerplant (Wärtsilä Energy, 2020)
Picture 6 District heating supply and return temperatures CHP plant (Wärtsilä Energy, 2019)
