Design and Numerical Study of Magnetic Energy Storage in Toroidal Superconducting Magnets Made of YBCO and BSCCO
Round 1
Reviewer 1 Report
In this manuscript, the authors want to express that “Regarding the design of the modular torus, it was obtained that for a 1.25 times increase in the critical current for a superconducting material, the dimensions of the torus were reduced by 7% to store the same amount of energy. Also, following a numerical parametric analysis, it resulted that for to maximize the amount of energy stored, the thickness of the torus modules must be as small as possible, without exceeding the critical current. Another numerical analysis showed that the energy stored is maximum when the major radius of the torus is minimum, i.e. for a torus as compact as possible.”
The literature and motivation are described.
The method section requires modification, making it easy for readers to understand.
The result and discussion require modification, making it easy for readers to understand. For example, some statements should be given in the figure caption instead of one-word (see Fig. 7, only one word “YBCO”).
In summary, the manuscript can be reviewed after major revision.
Some major and minor suggestions are listed below.
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The suggestions are structured as shown below.
[Suggested point][Position]
Descriptions.
[[Major suggestions]]
1. [Manuscript structure][Introduction]
There are two paragraphs in the introduction section. The second paragraph provides “In this work” information, while the other information is given in the first paragraph. The first paragraph becomes a huge one, causing dyslexia for readers easily. A good way to solve this problem is to separate history literature, motivation, etc.
2. [Manuscript structure][Conclusion]
Where is the conclusion section?
There are several sentences “In conclusion,…” at the end of the discussion section.
It is better to provide a conclusion section for readers.
3. [Missing information][Author contributions]
Please give information. It is necessary for the publisher.
4. [Missing information][Conflicts of Interest]
Please give information. It is necessary for the publisher.
[[Minor suggestions]]
1. [Terminology][Line 9, Abstract]
“The Superconducting Magnet Energy Storage (SMES)…” should be modified to “the superconducting magnet energy storage (SMES)….” Using uppercase is unnecessary.
2. [Terminology][Line 16, Abstract]
“…Bismuth strontium calcium copper oxide (BSCCO)…” should be modified to “…bismuth strontium calcium copper oxide (BSCCO)….” Using uppercase is unnecessary.
3. [Terminology][Line 17, Abstract]
“…Yttrium barium copper oxide (YBCO)…” should be modified to “…yttrium barium copper oxide (YBCO)….” Using uppercase is unnecessary.
4. [Abbreviation][Line 37]
The abbreviation (HTS) should be stated with the full name before using it.
5. [Abbreviation][Line 37]
The abbreviation (SMES) has been mentioned in line 32. It is unnecessary to declare the abbreviation again.
6. [Abbreviation][Line 41]
The abbreviation (GM) should be stated with the full name before using it.
7. [Abbreviation][Line 52]
The abbreviation (LTS) should be stated with the full name before using it.
8. [Terminology][Line 62]
The term J(B) should be stated with the full name before using it.
9. [Talk about other researchers’ work][Line 66]
It is better to write “Shi and Liang [11] present...” instead of “Paper [11] present...”
10. [Missing information][Line 69]
It seems something missing in the sentence “Therefore, in superconducting wires the current densities are not uniformly distributed because the screening currents, affected its.”
11. [Redundant information][Line 69]
The words “In the paper [11]” in the sentence “In the 69 paper [11], different methods for determining anisotropy are presented.” could be eliminated, since the authors are talking about the paper [11] (from Line 66).
12. [Talk about other researchers’ work][Line 66]
It is better to write “Also, Nugteren [12] presents...” instead of “Also, the paper [12] presents...”
13. [Terminology][Line 73]
“…Bismuth strontium calcium copper oxide (BSCCO)…” should be modified to “…bismuth strontium calcium copper oxide (BSCCO)….” Using uppercase is unnecessary.
14. [Terminology][Line 74]
“…Yttrium barium copper oxide (YBCO)…” should be modified to “…yttrium barium copper oxide (YBCO)….” Using uppercase is unnecessary.
15. [Abbreviation][Line 75]
The abbreviation (2G) should be stated with the full name before using it.
16. [Terminology][Line 78]
The term Jc should be stated with the full name before using it.
17. [Terminology][Line 84]
Please modify the term $YBa_2Cu_3O_{7-x}$.
18. [Terminology][Line 97]
The term $W_{mag}$ is suggested to be stated with the full name before or after using it. Statement text should not be too far from where the symbol appears, causing readers to spend a lot of time looking for symbol explanations.
19. [Terminology][Line 104]
What is $beta_t$? The term should be given explicitly.
20. [Strange expression][Line 110]
It is strange to write “Their close form expressions are [14]:”
What did it mean?
21. [Terminology or typo problem][Line 116]
What is $beta$? Is it $beta_t$?
22. [Strange term][Line 127]
What is the term [Hass] in the sentence “The total cost of conductor is directly proportional to the Ampere-meters of conductor and is independent of current [Hass].”?
23. [Notation consistency][Line 134]
Wmag or $W_{mag}$?
For example, in line 264~265
There should be a comma after the equation.
There should be no indent before the sentence "where ?? is the current density and ? is the magnetic vector potential (Wb/m)."
Many other examples are given in the "Comments and Suggestions for Authors."
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is devoted to the design and the numerical study of magnetic energy storage in toroidal superconducting magnets made of YBCO and BSCCO. In my opinion, the paper lacks novelty. However, it can be published after some refinement. Here are some comments:
1. Please, provide a figure showing the geometric parameters used in the paper. It will simplify understanding the paper.
2. Expressions 19-22 are superficial. The referring to Comsol implementing FEM is enough.
3. Is there any interaction between modules. Is it taken into account?
4. Describe the physical reason of increasing the stored energy with an increase of the number of modules.
5. I am not sure that efficiency is a good term in this context. Maybe, something like specific energy is better.
6. Check the figure numbers. I can’t find Fig. 6. Fig 5a is blurred.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
Review on manuscript entitled “Design and numerical study of magnetic energy storage in toroidal superconducting magnets made of YBCO and BSCCO”.
Recently announced discovery of LK-99 makes this work to be situated in very attractive topic. This is the reason I am considering this work as interesting for publication, however many drawbacks can be pointed, therefore a major revision must be performed.
1) Introduction may be enlarged. You may cover more direction, including new materials, magnetic modeling, thermal modeling, mechanical modeling, new designs, novelties in insulation. Some recent works are:
doi.org/10.3390/molecules28145522
doi.org/10.3390/ma16145111
doi.org/10.3390/su151310736
doi.org/10.3390/coatings13061093
doi/10.1109/TASC.2023.3251948
2) HTS are not optimal for SMES, they are composites as presented in Figure 1, they have problems for very long coils.
3) Describe your SMES design carefully. Make a schematic drawing of the toroidal coil in the beginning of section “2. Toroidal superconducting coil”. Indicate all design symbols there. Explain better Qt. Lorentz force expression uses coil radius not torus radius. Check all expressions carefully. Equations (1) and (2) are unusable without FEM.
4) Figures 1-3 are very poor. Improve them. At the end of the section “2.2. YBCO vs. BISCCO 2223 superconductors” provide a Table with material constrains that appears and are used in your design process – extract them from last rows of Table 1, add forces, Tc, Bm, etc. Current Table 1 will be Table 2.
5) Comsol modeling looks redundant. Don’t get why it is used here? You get all design requirements from the initial expressions. You can keep FEM modeling, it is good to have. Figure 5/a are very similar, indicate the differences, include size bar for the scale. Second Figure 5 (there are two!) is not clear where in the design is acquired?
6) MVP modeling formulation is not very suitable for superconducting applications, there are exclusions for HTS, which are not bulk superconductors. Comparison on usability of available modeling formulations could be found here
doi/10.1109/SIELA49118.2020.9167073
doi/10.1109/TASC.2018.2801322
7) Flowchart on Figure 4 must be redrawn with typical for algorithm symbols.
8) Figure 7 results are not explained. What is g there?
9) There is no Conclusion section.
English must be improved.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
In the revised manuscript, much missing information has been added to clear the descriptions. Some additional descriptions have been added to enhance the major statements.
In summary, the revised manuscript fits the journal’s criteria for publication.
Author Response
Thank you for your support !
Reviewer 3 Report
I am partially satisfied with the improvements made so far. Direction of work is clear, but methodology and results are not presented in an optimal way. In my opinion, some more efforts are needed:
1) Please check with the editor if copyrighted figures, from other authors, could be used in this journal.
Figure 1a -> [26]
Figure 1b -> [27]
Figure 3a -> [28]
Figure 3b -> [29]
2) Section “2. Toroidal superconducting coil” needs better description of the SMES design.
3) Figure 4 is not easy to follow, Energy Wmag is calculated before the COMSOL modeling? After it is calculated two more times? If this is an optimization problem, it is nor well defined and algorithm is not well explained.
4) Equation (4) is not well explained. Is it used for the optimization instead of COMSOL model? Please, define all symbols there.
5) Comparison of results from model is very difficult (Figure 5 a-b, Figure 6 a-b, Figure 7 a-b). Use text labels to indicate interesting differences and optimal values.
6) Make a table with the best SMES designs proposed by you here.
In my opinion English must be improved.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
