Bi-Level Optimization of the Energy Recovery System from Internal Combustion Engines of a Cruise Ship
Round 1
Reviewer 1 Report
The paper presents a bi-level and multi-objective optimization procedure for an on-board energy system a a cruise ship. Even though the optimization methodology itself does not represent a novelty to the scientific community, the case study analysed is different to those typically analysed using this approach and is of great interest. The paper is in general well structured and quite suitably written. However, there are some issues related to the article that should be faced in order to improve its quality:
- A Nomenclature section is indispensable for understanding the paper; lots of acronyms and nomenclature are introduced throughout the paper
- Avoid lumped references as far as possible. Highlight the core of those references and indicate which are your contributions with respect to those cited
- A deep revision of the document should be carried out in order to correct English mistakes and errata
- P MANOUV, power for the maneuvering propellers in the port entry / exit phases, is defined in line 160, but it is not contemplated in Figures 1 and 2
- Does P HVAC only refer to cooling (as stated in line 161) or it also includes the thermal necessities satisfied by the so-called steam vector and is considered within P pump-galley-lights? It should be clarified.
- What does Evaporat. “A” + “B” in Figures 3 and 4 refer to? Is that the heat recovery from the cooling circuit of the ICEs? Once again, this nomenclature should be conscientiously defined and properly used.
- Are the steam user demands constant throughout a whole week, as depicted in Figures 3 and 4?
- The terms defined do not always correspond to those employed in Figures 1 to 4 (eg. Hotel ONLY-Hot water in Figure 3)
- In Figure 5, shouldn’t the steam line (green line) be connected to the HTWS boiler according to what is explained in line 239 in page 8?
- The format of Figure 8 should be adapted to that of the other figures
- Which are the average insolation values of a typical day mentined in line 449? Are losses due to orientation of the solar technologies (thermal and PV) considered?
- The quality of Figure 9 should be improved
- Which are the storage conditions (level of storage) before and after the week analysed takes place? It should be specified and properly justified.
- Why modeFRONTIER software? Why not open access tools such as OpenSolver, for instance? The suitability of the selected software over other options should be further discussed and better justified.
- Taking into account the differences existing between the optimum solutions for the two operation weeks selected, since the ship will work under both summer and winter conditions, it would be very interesting, in order to complete the work, to address the joint global optimization
Author Response
Dear Reviewers,
the full Rebuttal is attached.
Kind Regards,
Mauro REINI
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Reallly nice job. Motivation of the paper clearly introduced and enough references of previous work and current state of art are provided. The strategy followed is interesting in this scope where size of the systems increases computational complexity of the optimization procedures. Clonclusions are acurate and well argumented.
Nevertheless, some minor improvements shoud be required:
Some minor errors have been detected in language (as in line 207 where ‘has defined’ should be ‘has been defined’).
Figures should be clarified. For instance:
- Figures 1 and 2. Pelect at this point seems to be Pelect the total produced power, nevertheless, for clarity purposes should be defined. Also in figure 1, P HVAC, even when it is zero, could be included in accordance with figure 2.
- Legends in figures 3 and 4 are different that data series defined in lines 178 – 193.
- Figure 5. Naming conventions should be clarified. Footnote of this figure and the explanation given in lines 199 and 200.
Author Response
Dear Reviewers,
the full Rebuttal is attached.
Kind Regards,
Mauro REINI
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have addressed the suggestions previously made and the quality of the paper has improved notably. No further modifications are proposed.
