Comparative Analisys Of Energy Efficiency Indicators For A Crude Oil Super Tanker Ship

COMPARATIVE ANALISYS OF ENERGY EFFICIENCY INDICATORS FOR A CRUDE OIL SUPER-TANKER SHIP

Inginer Cătălin Faitar, Conf. Univ. Dr. Ing. Iordan Novac

Constantza Maritime University

ABSTRACT

Main ideea of this paper is not only the study of the Energy Eficiency Design Index for a crude oil super tanker ship, witch is a mandatory technical measure for the new ships, but also the study of Energy Eficiency Operațional Indicator whitch is a voluntary mesurement for ships in service.

Keywords: energy eficiency design index, energy eficiency operațional indicator, technologies

1. INTRODUCTION

This paper aims is to improve the energy performance of a crude oil super tanker ship of 305000 dwt, by studying the possibility of introducing alternative energy sources and improving existing equipment onboard.

Initialy, the ship has no energy efficiency technologies but, for this papaer, our purpose is to introduce alternative technologies on board like shaft generators and motors, wind turbines and photovoltaic pannels. After that we calculate efficiency operational index and indicator for both states of ship and conclude the results.

2. CONSIDERATIONS ON ENERGY EFFICIENCY OPERATIONAL INDEX – EEOI AND ENERGY EFFICIENCY DESIGN INDEX – EEDI

2.1.Energy Eficiency Design Index – EEDI

Energy Efficiency Design Index (EEDI) is a measure of ships energy efficiency (g/t∙nm) and is calculated by the following formula:

(1)

CF – is a non dimensional conversion factor for fuel consumption, measured in g and CO2 emission,

Vref – is the ship speed, measured in nautical miles per hour (knot),

Capacity – is deadweight of the ship,

P – is the power of the main and auxiliary engines, measured in kW,

PME(i) – is 75 per cent of MCR for each main engine,

(2)

PPTO(i) – is 75 per cent of nominal power of each shaft generator,

PPTI(i) – is 75 per cent of the rated power consumption of each shaft motor divided by the weighted average efficiency of the generators,

Peff(i) – is the output of the innovative mechanical energy efficient technology for propulsion at 75 per cent main engine power,

PAEeff(i) – is the auxiliary power reduction due to innovative electrical energy efficient technology measured at PME(i),

PAE – is the required auxiliary engine power to supply normal maximum sea load including necessary power for propulsion machinery / systems and accommodation,

For the reference crude oil super tanker, main engine has a power up to 10000 kW, and PAE is writted:

(3)

SFC – is the certified specific fuel consumption, measured in g/kWh, of the engines,

fj – is a correction factor which for the crude oil super tank is written:

(3)

fw – is a non-dimensional coefficient indicating the decrease of speed in representative sea conditions of wave height,

feff(i) – is the availability factor of each innovative energy efficient technology,

fi – is the capacity factor for any technical / regulatory limitation on capacity, and should be assumed to be one (1.0) if no necessity of the factor is granted:

(4)

2.2.Energy Eficiency Operational Indicator – EEOI

The Energy Efficiency Operational Indicator is defined as the ratio of mass of CO2 (M) emitted per unit of transport work.

The Energy Efficiency Operational Indicator is calculated with this formula:

(4)

The unit of EEOI depends on the measurement of cargo carried or work done, e.g., tonnes CO2 / (tonnes ∙ nautical miles), tonnes CO2 / (TEU ∙ nautical miles), tonnes CO2 / (person ∙ nautical miles), etc

3. CALCULATION OF ENERGY EFFICIENCY INDICATORS FOR TWO KIND OF POWER SYSTEM CONFIGURATIONS

3.1.Calculation of Energy Eficiency Design Index for crude oil super tanker in design version

To calculate the EEDI will adopt a number of parameters for the main engine, auxiliary engines, innovative technology and transport parameters according to the formulas below.

Parameters for main engine:

1.Conversion factor for heavy fuel oil:

(5)

2.Main engine power:

(6)

3.Specific fuel consumption:

(7)

Parameters for auxiliary engines:

1.Necesary power for auxiliary engines:

(8)

2.Conversion factor for marine diesel oil:

(9)

3.Specific fuel consumption:

(10)

4.Corection factor:

(11)

5.Power for shaft generator (for design ship there is no shaft generators):

(12)

6. Availability factor of each innovative energy efficient technology.

At design ship there is no efficiency technology.

(13)

7. Auxiliary power reduction due to innovative electrical energy efficient technology.

At design ship there is no efficiency technology.

(14)

Parameters for inovatie technology:

At design ship there is no efficiency technology.

Parameters for ship transport work:

1.Capacity factor:

(15)

2. Factor for decrease of speed in representative sea conditions of wave height:

(16)

3. Ship speed:

(17)

4.Ship deadweight:

(18)

After these parameters, we can calculate Energy Eficiency Design Index for crude oil super tanker in design version:

(19)

(20)

(21)

Figure 1 Value and interpretation of EEDI for ship initial design

After calculation is concluded that value of EEDI are within the tier 1 and tier 2 (figure 1). So, for design ship we have a good result.

3.2.Parameters for calculation of Energy Eficiency Design Index for crude oil super tanker with energy efficient technologies.

For crude oil super tanker ship we adopt three type of energy efficient technologies onbord:

shaft generator

wind turbines

photovoltaic pannels

Against 1.1 paragraph we have some parameters for efficient ennergy:

1.Power for shapt motor:

(22)

(23)

2.Power for shaft generator:

(24)

(25)

3.Availability factor of each innovative energy efficient technology (we have the same factor for wind turbines and photovoltaic pannels).

(26)

4.Auxiliary power reduction due to innovative electrical energy efficient technology.

This time, we have wind turbines ennergy and photovoltaic pannels ennergy like electrical energy efficient technology:

(27)

(28)

3.3.Calculation of EEDI (option 1, we use shaft motor, wind turbines and photovoltaic pannels)

(29)

(30)

(31)

At point 3.3. we had a value of 2.14 .

So, like result, was a drop with 0.11.

Figure 2 Value and interpretation of EEDI for ship with efficient energy and shaft motor

3.4.Calculation of EEDI (option 2, we use shaft generator, wind turbines and photovoltaic pannels)

(32)

(33)

(34)

At point 3.4. we had a value of 1.93 , so like result was a drop with 0.21.

Figure 3 Value and interpretation of EEDI for ship with efficient energy and shaft generator

3.4.Calculation of Energy Eficiency Operational Indicator for crude oil super tanker without efficiency energy technologies

To calculate EEOI we will adopt a ship voyage of 30 days. So, we have parameters below.

1.Fuel consumed (tones):

(35)

(36)

2.Carbon factor for each type of fuel:

(37)

(38)

3.Crude oil transported:

(39)

4.Distance during ship vayage (miles):

(40)

(41)

In conclusion we observe that EEOI value is 2.253 gCO2/t x mile. In figure no. 4 we had good result.

Figure 4 Interpretation of EEOI for ship without efficient techologies

3.5.Calculation of Energy Eficiency Operational Indicator for crude oil super tanker with efficient energy technologies

We calculate EEOI for a voyage of 30 days. To calculate the operational index we adopt the parameters below.

1.Fuel consumed (tones):

(42)

(43)

2.Carbon factor for each type of fuel:

(44)

(45)

3.Crude oil cargo:

(46)

4.Distance during ship travel (miles):

(47)

(48)

In conclusion we observe that EEOI value is 2.15 gCO2/t x mile. In figure no. 5 we had a very good results.

Figure 5 Interpretation of EEOI for ship with efficient technologies

4. COMPARATIVE ANALISYS OF ENERGY EFFICIENT TECHNOLOGIES RESULTS

4.1.Comparative analisys of Energy Eficiency Design Index.

In conclusion, comparative results for the values ​​of EEDI are:

1.for option no.1 with shaft motor, wind turbines and photovoltaic pannels, we had a value of 2.03 , against 2.14 with ship without energy afficient technologies. So, was a drop with 0.11 ;

2.for option no.2 with shaft generator, wind turbines and photovoltaic pannels, we had a value of 1.93 , against 2.14 with ship without

energy efficient technologies. So, was a drop with 0.21 .

Figure 6 Interpretation of EEDI

4.2.Comparative analisys of Energy Eficiency Operational Indicator

Calculating EEOI, we observe that value is 2.15 gCO2/t x mile against the ship voyage without efficient ennergy technologies with value of 2.253 gCO2/t x mile. So was a drop of 0.10 gCO2/t x mile.

Figure 6 Interpretation of EEOI for ship with efficient technologies

5. CONCLUSIONS

By calculating energy efficiency indicators for two kind power configuration of a crude oil super tanker ship, we try to show witch is the difference between a ship with and without inovative technologies onboard.

In design state, power configuration of ship was only the main engine, auxiliary engines and boiler.

Also, we adopt efficient technologies onboard like shaft motor and generator, wind turbines and photovoltaic pannels.

In modern state, power configuration of ship was the main engine, auxiliary engines, boiler, shaft motor or shaft generator, wind turbines and photovoltaic pannels.

After calculation of energy efficiency indicators we had results with a difference of 0.11 and 0.21 for Energy Efficiency Design Index – EEDI and 0.10 gCO2/t x mile for Energy Efficiency Operational Indicator – EEOI.

6. REFERENCES

[1] NOVAC, I., Ship theory and construction, Part 2 – Ship hydrodynamics, Universitatea Maritimă, Constanța, 2013.

[2] TAIRA, K., NAKATA J. Sphelar cell array module, Japan, 2013.

[3]MUSCATO, D., GANDE E.BAUER Z., Photovoltaic Technology in the Shipping Industry A feasibility study on the use of solar energy for diesel abatement in Handymax class cargo vessels, Japan, 2011.

[4] MAN Diesel Ltd., Shaft Generators for Low Speed Main Engines, 2011.

[5] FAITAR C. Concepte de modernizare energetică a unui VLCC de 305000 tdw. Calculul și proiectarea sistemelor energetice auxiliare. Universitatea Maritimă Constanța, 2014.

[6] www.pveducation.org/pvcdrom/modules/module-circuit-design, accessed at 22.11.2015