Energy and Exergy Analysis of a Cruise Ship

Artikel i vetenskaplig tidskrift, 2018

In recent years, the International Maritime Organization agreed on aiming to reduce
shipping’s greenhouse gas emissions by 50% with respect to 2009 levels. Meanwhile, cruise ship
tourism is growing at a fast pace, making the challenge of achieving this goal even harder.
The complexity of the energy system of these ships makes them of particular interest from an
energy systems perspective. To illustrate this, we analyzed the energy and exergy flow rates of a
cruise ship sailing in the Baltic Sea based on measurements from one year of the ship’s operations.
The energy analysis allows identifying propulsion as the main energy user (46% of the total) followed
by heat (27%) and electric power (27%) generation; the exergy analysis allowed instead identifying
the main inefficiencies of the system: while exergy is primarily destroyed in all processes involving
combustion (76% of the total), the other main causes of exergy destruction are the turbochargers,
the heat recovery steam generators, the steam heaters, the preheater in the accommodation heating
systems, the sea water coolers, and the electric generators; the main exergy losses take place in the
exhaust gas of the engines not equipped with heat recovery devices. The application of clustering of
the ship’s operations based on the concept of typical operational days suggests that the use of five
typical days provides a good approximation of the yearly ship’s operations and can hence be used
for the design and optimization of the energy systems of the ship.