Innovative engine configurations and waste heat recovery solutions employed on large cruise ship to meet new environmental regulations

Due to recent regulations imposed by IMO (Int. Maritime Org.), pollution emissions produced by large ships are now under strict control, and a widening part of the seas (called SECA) is now accessible only by ships with a limited SOx and NOx output. To meet the new regulations, ships propelled by HFO burning Internal Combustion Engines (ICEs) can be equipped with abatement devices such as scrubbers and SCR systems. Although the employment of those devices seems to be the route ship-owners will prefer, other methods can be considered such as the use of MGO, a more expensive fuel but with lower sulphur content. The use of MGO allows considering a further and more drastic modification of the power system, namely the use of Gas Turbines (GTs) in place of ICEs. Gas Turbines, despite of being less efficient, are much lighter, more compact, and can easier reach low NOx emissions than ICEs. Even if these aspects are theoretically well known, there are still difficulties in finding studies reporting quantitative analysis (weight, dimensions, fuel consumption) that compare GTs and ICEs power systems employed on board. The present thesis aims at providing these data by analyzing different solutions applied to a real case. Unlike other studies, the work is focused on a cruise ship rather than on a cargo ship, because cruise ship’s operation profile is more variable during the trip. Finally, solutions to minimize the gap of fuel consumption between GTs and ICEs is also discussed.