Fault Detection and RUL Estimation for Railway HVAC Systems Using a Hybrid Model-Based Approach
Round 1
Reviewer 1 Report
An interesting work. The manuscript presents interesting research and appropriate for the journal.
The abstract is clear and to the point, stressing both the specific application and the generic aspects of the work.
Mathematical relationships are correctly.
The description of the experimental methodology, the presentation of results and the discussion of these are clear and rigorous.
From the scientific point of view, the paper is interesting; is suitably prepared for publication in the Sustainability Journal.
The general idea of the paper is appealing.
The formal level of the manuscript is followed according to the journal template.
The content of the manuscript has an adequate and very good explanatory value.
Minor revision:
Authors should improve the readability of figures (Fig. 5, Fig. 6, Fig. 7).
Author Response
Dear reviewer,
Thank you for your comments. Please, find attached the document where I describe how your comments are added to the updated paper.
Thank you very much.
Warmest,
Antonio
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors presented an article on the validation of the hybrid model-based approach to maintaining railway HVAC systems. The article is not well presented. Authors should consider and work through several points:
- The literature review presented in the introduction is quite poor. The authors ignored the issues related to maintaining the temperature and CO2 limit in passenger carriages. There is no such research? How are now such problems being dealt with today?
2. In the introduction, there is no presentation of the research gap, that this article fills.
3. In the discussion, there is no presentation of reference to the research results of other authors.
4. Conclusions should present the answer to the purpose of the article and not summarize the research description.
5. One should answer the question about the purpose of the article, is it really as described by the authors in the abstract?
6. It seems that the title of the article does not correspond to its content, you should consider what is presented with the greatest emphasis in the research part of the article.
7. The purpose of the article is presented as: "This paper proposes a hybrid model-based approach (HyMA) to overcome the lack of failure data on an HVAC system installed in a passenger train carriage". The text lacks the description of "the lack of failure data" - what type, in what quantity?
8. Abstract - "The model obtains remarkable accuracy." and "Both models obtain a remarkable accuracy." - the wording is not correct. What is "remarkable"? "In relation to" what? "Remarkable" is how much?
9. Figure 4. Principal items considered in the studied HVAC system. - the drawing is illegible.
10. Figure 5. Principal components of the modeled HVAC system. - the drawing is illegible.
11. Section 2.2.2. Synthetic data generation - "... data related to a simulation are individually saved in a table." - in what table? What is its structure? What was included?
12. Section 2.2.2. Synthetic data generation - "The data-driven model presented in this research is trained, validated, and tested to detect fi ve different faults: ..." - how is it trained, tested, and validated? What Authors used the methods?
13. Section 2.2.3. Extraction Feature - "The data-driven model developed in this research uses supervised learning methods." - what methods of supervised learning did the authors use?
14. The authors repeat the information "The data-driven model is trained, validated, and tested by real data and synthetic data." In several places, but authors do not write how and with what methods they perform these activities. Section 2.3. The data-driven model contains a theoretical description of the methods of supervised learning that can be applied, but the authors did not indicate what the authors used in the research.
Author Response
Dear reviewer,
Thank you for your comments. Please, find attached the document where I describe how your comments are added to the updated paper.
Thank you very much.
Warmest,
Antonio
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper is structured well in writing and content.
However, the authors should revise following some small comments below:
1) Should provide more experiment results on other HVAC datasets and then compared with their method result.
2) Should provide more experiment result on other prior methods on their dataset and compare to their proposed method results.
Author Response
Dear reviewer,
Thank you for your comments. Please, find attached the document where I describe how your comments are added to the updated paper.
Thank you very much.
Warmest,
Antonio
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors addressed all comments of the reviewer. The revised manuscript became more readable. The article in its current form is much better and is suitable for printing.
