A Review of Energy Overconsumption Reduction Methods in the Utilization Stage in Compressed Air Systems

Round 1

Reviewer 1 Report

The paper presents the literature review in the area of energy efficiency of pneumatic systems. This review summarizes methods and approaches for improving oversizing and energy overconsumption. This topic is very relevant, because the current level of efficiency of pneumatic systems is very low. The review is quite wide. Out of 90 works, more than 60 were published in the last 5 years. The article is well organized and clearly presented. It analyzes the shortcomings of the methods used to increase the efficiency of pneumatic systems and shows the problems of their implementation. In conclusion, the most promising directions for further work and the difficulties of their implementation are noted.

The review article is of undoubted interest to readers, I recommend it for publication after the minor correction.

Remarks.

1. Figure 4 is the same as Fig. 3b which has already been discussed.

2. Lines 348-350: In the sentence, both references [44] and [46] are the same publication.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The topic of the paper as stated in the title and abstract seems to be quite relevant and interesting. Nevertheless, while reading the article, it is a little harder to find an adequate structure and elements to allow a proper understanding of the authors' original contribution to knowledge and their work's relevance.

The paper can therefore be accepted after a major revision of its structure and organization.

In particular:

- According to title and abstract, I would be expecting the paper's structure to resemble the following: Introduction (highlighting the importance of the topic and the need for the work presented), Methodology (explaining the methodology used for the review), Results (highlighting results from the review and maybe adding a paragraph on the method of exergy analysis of pneumatic systems if needed), Discussion and conclusions. The current structure is more suitable to a technical report rather then to a scientific paper.

- The introduction to the paper and the introduction to chapter 2 are too general and give information that is so well-known it could be just omitted.

- The literature review needs some extending and updating. There are some papers quite relevant to the topic that are missing (e.g. 10.1016/j.energy.2019.115879).

- According to title and abstract the paper should focus on the utilisation stage, while it actually gives the same relevance to other stages.

- The need for the exergy analysis method proposed is not very clear, as it is its originality and novelty.

- The results of the review related to the utilisation stage should be better highlighted and distinguished by those solely related to oversizing. In addition, it could be useful to distinguish between efficiency improvement suggestions that are state-of-the-art and those that are currently being developed or under study.

-Please make some effort to ensure all pictures are relevant (e.g. picture 4 is exactely the same as picture 3b).

Please proceed with and in-depth proofreading of the paper, as there are several minor shortcomings.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors have done a nice job in reorganizing the paper. Nevertheless, the structure does still seem a little confusing. In particular, it is not very clear how all the exergy-methodology-related bit fits with the rest of the paper. If all that bit is removed, in fact, it looks like a review paper on energy overconsumption reduction methods in the utilisation stage in compressed air systems (coherently with title and abstract) missing the methodology chapter (how was the review conducted? what keywords used? what search engines? from which year? how were the paper selected?). If we only look at the exergy-methodology-related bit it looks like a paper where an original application of a methodology is presented, with adequate review of previouly proposed methodologies on the same topic. Basically, I think authors are trying to merge two papers in one, where they could actually focus on one of the two and use the rest of the material in another paper. If they anyway wish to present both research themes in this paper, I would suggest to accurately separate them as two different sub-sections including a review and methodology chapter in each of them.

Some shortcomings are still present in the paper. Some examples (just examples, there are several in the paper):

- "Pneumatic systems use the energy of compressed air to realise manufacturing automation processes by implementation of complex handling and motion tasks" --> improper use of the verb "realise";

- "In addition, a method of exergy analysis of pneumatic systems will be presented" --> use of "of" instead of "for";

- Therefore, scientists and researchers are quite well-respected on the topic of compressed air systems, investigating the possibilities of improving energy efficiency, reducing noise, and increasing operational precision" --> this phrase does not make sense, there might be a verb or preposition missing.

Author Response

Please look at the attachment.

Author Response File: Author Response.pdf