development of ship engine heat driven absorption ... · sea going results the target roro ship...
TRANSCRIPT
Dawei Wu
Aitor Juando
Tony Roskilly
Guohong Tian
DEVELOPMENT OF SHIP ENGINE HEAT DRIVEN ABSORPTION REFRIGERATION AND COOLING
STORAGE SYSTEM
SusTEM Special Sessions
on
Thermal Energy Management
1
Overview
1. Introduction and background
2. Methodology
3. Absorption chiller modelling
4. Ice slurry cooling storage
5. Results and discussion
6. Conclusion
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1. Introduction and background
Energy cost has entitled about 50% of the ship running cost
Ship energy system:
propulsion, electricity,
heating, cooling
Massive heat available
in engine exhaust gas
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1. Introduction and background
This presented paper comes from part of an EU FP7 project
“TEFLES” – tefles.eu
A RoRo ship has been chosen for this particular study
Aim is to study the feasibility of
utilising exhaust gas heat to drive
absorption chiller and corresponding
cooling storage from a system point
of view
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2. Methodology
Sea going measurement
Engine performance
Existing refrigeration layout
Travel schedule
New refrigeration system development
Absorption chiller modelling
Ice slurry storage CFD modelling
Estimation of carbon abatement
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Sea going results
The target RoRo ship runs between Vigo and St Nazaire ports, 44 times a
year
Sea going schedule is very important for system design
Cooling requirement is 190kW, consumes 43kW of electricity
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OPERATIONAL PROFILE
14,5
15
15,5
16
16,5
17
17,5
18
18,5
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
time [min]
speed [
kn]
Trip time draft speed
[1] Vigo- St Nazaire 40.8 6.7 m 15 kn
[2] Vigo-St Nazaire 26.8 6.7 17.9/18 kn
[3] St Nazaire-Vigo 29.8 6.2 16.3 kn
[4] St Nazaire- Vigo 40.8 6.7 m 15.5 kn
3. Absorption chiller modelling
Utilising exhaust gas heat after dry scrubber
Ice slurry tank designed for cooling energy storage - at port application
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3. Absorption chiller modelling
Single stage absorption cooling cycle was modelled
Ammonia/water couple were chosen as working fluids
Ideal thermodynamic absorption cycle
Model built in EES
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4. Ice slurry cooling storage
Ice slurry cooling storage was chosen to provide stable cooling for a
target of 15 hours continuous cooling for the ship
15% Ethylene Glycol was used as working fluid
CFD was used to predict the performance of the ice slurry tank
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5. Results and discussion
Absorption chiller modelling
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COP versus heating temperature Heat transfer in the major heat exchangers
Ammonia mass fraction difference in the desorber COP versus ice making temperature
5. Results and discussion
Ice slurry mixing tanks CFD prediction
11 Small mixing tank Large mixing tank
5. Results and discussion
Cooling storage durability
After 15 hours, the 25 m3 ice
slurry tank inside temperature is
about -5oC, which sufficiently
meets the design target
The new designed system can
reduce CO2 emissions for nearly
1200 ton per year for this ship
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6. Conclusion.
A feasibility study of utilising waste heat from ship engines to drive
absorption refrigeration and ice slurry cooling storage system was
presented.
Optimised ideal absorption refrigeration heating source temperature was
identified as 110oC; that can be matched by the ~300oC exhaust
temperature to provide sufficient cooling.
Ice production could potentially decrease the COP but achieve lower
evaporating temperature.
The proposed system could bring both energy saving and carbon
abatement for nearly 1200 tCO2 annually.
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Acknowledgement
• This research is sponsored by EU project TEFLES and the authors would also like to thank all the project partners for their contribution in this paper.
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