Experimental Investigation of the Performance of a Tuned Heave Plate Energy Harvesting System for a Semi-Submersible Platform

Round 1

Reviewer 1 Report

The proposed paper presents detailed experimental investigation on the performance of what the authors call ‘the THPEH system’, which was proposed and numerically investigated by the same authors.

I think the idea itself is interesting, but I have questions and comments as shown below, to which, I recommend, the authors pay due consideration and revise the manuscript accordingly.

1. I understand the proposed concept assumes that the harvested power is provided as part of the power consumed by the corresponding semi-submersible. Then, my question is if the power harvested by the proposed system could be not-negligible portion of the total power consumed by the corresponding semi-submersible. Otherwise, it is interesting but practically no use. In page 2, it is said that ‘the THPEH system could reduce up to 20% heave motion and provide annual 25-40KW energy for the platform’, but I cannot understand what ‘annual 25-40KW’ means. It doesn't make sense. It should be like ‘it provides xxx kWh annually’.

2. The term ‘tuned heave plate’ appears frequently in the manuscript, but it is not clear what is tuned to what. I suspect, for example, it might mean that the natural frequency of the heave plate is tuned to the frequency of the heave motion of the corresponding semi-submersible. Supposing that this is what the authors mean by ‘tuned heave plate’, then although the harvested energy could be large in regular waves of the corresponding motion frequency, but what about in irregular waves?

3. Miscellaneous matters

(1) Page 1, Lines 41-42

It is said that ‘However, due to its small water plane area and the draft, its heave motion is much larger than other type platforms’, but I understand one of the features of a semi-submersible is that its heave motion is quite subdued in relevant waves observed in real seas.

(2) Page 3, Lines 110-111

It is said that ‘Four tuned heave plates also can be considered as a multi-TMD system, and they will offer control moment for the platform to achieve the anti-roll or anti-pitch control’, but how can it be achieved?

(3) Page 5, Line 149

‘Fig.2.b.’ cannot be found.

(4) The term ‘control performance’ appears repeatedly in the manuscript, but what does ‘control performance’ mean? Is the THPEH supposed to be controlled? Then, how is it controlled?

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The paper "Experiment Investigation on the Performances of a Tuned Heave Plate Energy Harvesting System of a Semi-submersible Platform"  with Manuscript ID jmse-1484818 has been recommended for minor corrections.

The tunning and energy harvesting system are two unique approaches used and they show novelty and but the methodology needs to be better discussed on how it has been well applied. It is also an Original Submission and well prepared by the authors but requires some improvements on its quality. However, there are some technical observations.

STRENGTHS
1. The paper has good structure and outline.
2. The authors are technically sound in the subject area.
3. The analysis has been well conducted by the authors.
4. The authors have done a good introduction but should be improved upon. Link it together to get 3-4 paragraphs, as against the current 5  paragraphs.
5. Good references and well placed in the paper, but must be improved upon.
6. The paper has good highlight.
7. Good description of the model.
8. Good signposting. But could be improved.

9. The authors have done a good presentation of results.

The Weaknesses:
1. The paper requires some English Language editing and minor proof reading.

2. The paper has an sisue with signposting. At the last paragraph in introduction (Section 1), authors should do well to add an outline of what the paper will be discussing briefly for each section.
3. Improve the quality of some images as some figures should be bigger and more legible with better quality and better resolution.
4. Make sure that all abbreviations are defined. I recommend updating an the abbreviations and defining them or adding an abbreviations list at the end of paper, before references. Abbreviations like PTO should all be in the Abbreviations List.
5. In the discussion of results, more explanation and backing with relevant references should be carried out.
6. Add a new section- Section 5 to be Discussion and make Section 6 Conclusion. However, the present conclusions made in Conclusion section are good. It gives good summary but it should also highlight the main things.
   7. The study has an issue with validation. How did you calibrate the tunning system used and the heave plates? What controls were considered in the experiment? However, how did the authors validate the model? Add reference or website for documentation for the devices used in the setup and instrumentation.
   8. Can the authors include references to the governing equations for each rationale on the in their study? Most of the equations are not original to the authors but none was cited... add the references, please. It will improve the quality of the technical paper. Also reference any equation that is not original to the authors.
   9. What are the limitations of the framework for the study? Authors should include it 
   10. Authors should include the novelty of this research and some discussions on the theoretical framework- something to show or illustrate the uniqueness and advantage of the model, and highlight the key areas inside the paper. Authors should look at existing MDPI's JMSE journal papers and see how the highlights are presented. 
   11. After Section 5, authors should add acknowledgement after Informed Consent Statement and Institutional Review Board Statement, if applicable.
   12. Paper lacks any graphical abstract but it is recommended.
   13. The references need to be improved upon for better citeability, significance and higher impact. Add some MDPI's JMSE journal papers as this will help it not look like it was not prepared for JMSE.

 

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I have no further comments nor questions.

I judge the revised manuscript can be published in JMSE.