A Comprehensive Review on the Nucleate/Convective Boiling of Low-GWP Refrigerants: Alternatives to HFC Refrigerants
Round 1
Reviewer 1 Report
Work is original and can be published by revising the paper with suggested comments.
Comments for author File: 
Comments.pdf
Author Response
Author Response File: Author Response.pdf
Reviewer 2 Report
- The quality of the manuscript require improvement before and also general English and removal of typos. A few observations are listed below which needs to be addressed adequately.
- Why authors have selected R410A? I guess this is not relevant wrt R134a.
- Author considered R134a alternatives for this paper, however introduces R123 alternatives in Table 1. Need to be clarify in abstract, introduction etc. if author proposes to contrast properties of R123 alternatives also.
- Authors may want to clarify heat fluxes range in contrast to the type of application to make the data more usable for design engineers
- Many typos, needs corrections, for example line 196 to line 200 etc.
- R1234ze shows lower HTC than R134a, authors may want to validate this observation from other published data.
- Fig. 11 shows R404A alternatives, authors may want to introduce this earlier in introduction section and add relevant literatures.
- Authors have presented conclusion which are general in nature and lacks appropriate future directions.
- Further this article lacks comparison of observed HTC for various refrigerants wrt fundamental correlations/concepts for better clarity for design engineers.
Author Response
Response to Reviewer # 2 Comments
Dear Reviewer thank you for your kind and wise comments for the improvement of our draft and enhance the quality of our paper. we have responded to your comments below and modified it in the paper as well.
1. Why have authors selected R410A? I guess this is not relevant wrt R134a.
Response: Thank you for pointing out this error and the authors have included this in the abstract and introduction. Several significant low global warming potential substitutes for regularly used high global warming potential substances including R-134a, R404A, and R410A are discussed in this study.
2. Author considered R134a alternatives for this paper, however, introduces R123 alternatives in Table 1. Need to be clarify in abstract, introduction etc. if author proposes to contrast properties of R123 alternatives also.
Response: In Table 1 R-123 is introduced as a low-pressure low global warming potential (GWP<79) substitute to R-134a itself. The authors didn’t attempt to introduces R-123 alternatives in Table 1 separately.
3. Authors may want to clarify heat fluxes range in contrast to the type of application to make the data more usable for design engineers
Response: For the needs of design engineers, the authors have briefly and duly motioned all the operating conditions, such as heat fluxes, mass fluxes, saturation temperatures ranges, and the geometric aspects of the heat exchanger being discussed in the respective tables.
4. Many typos, needs corrections, for example line 196 to line 200 etc.
Response: Thank you for pointing out this issue and the authors have refined the draft.
5. R1234ze shows lower HTC than R134a, authors may want to validate this observation from other published data.
Response: From (Ji et al., 2021), the HTC of R-134a and R-1234ze(E) for enhanced tubes are found to be about the same. At some higher heat fluxes, HTCs are independent of the surface structures, meaning nucleate boiling is in control. The HTC of R-1233zd(E) is 40% lower than those of R-134a for both tubes at identical conditions.
6. Fig. 11 shows R404A alternatives, authors may want to introduce this earlier in introduction section and add relevant literatures.
Response: Thank you for pointing out this issue and the authors have incorporated this into the abstract and introduction.
7. Authors have presented conclusion which are general in nature and lacks appropriate future directions.
Response: Thank you for pointing out this issue and the authors have refined the draft.
8. Further this article lacks comparison of observed HTC for various refrigerants wrt fundamental correlations/concepts for better clarity for design engineers.
Response: For the need of design engineers, the authors have briefly discussed comparison of the observed HTC for various refrigerants with respect to fundamentals and the correlations in the respective tables. This will make engineers easier to access the alternative refrigerants.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors have revised the manuscript with given suggestions. Now it is acceptable for publication in this journal.
Author Response
Dear Reviewer,
I would like to express my gratitude for the thoughtful and considerate remarks you provided in order to help us improve our draft and the overall quality of our paper.
Thank you Sir / ma'am
Reviewer 2 Report
1. Many typos still remains in the revised manuscript
2. Table 2 observations looks incorrect, need to revisit
3. Line 215 to 218, Please rephrase as they are confusing
4. Line 239 to 242, introducing irreversibility vs R410A looks abrupt, need to rephrase and state the conditions of observations
5. Fig 12, can be divided in three subsets, not readable in current format
6. Table 3, Kim C,H and Kim N,H, is same as (67)?
7. Table 5, geometries of BPHE not clear, information is not consistent, suggestion to revise the Table and provide details of BPHE in a structured format
8. Line 538 to 539, High speed Vapor...? Need to explain in detail the reason
9. Conclusion still do not have heat fluxes and mass fluxes ranges for which the review has been conducted, this would be very helpful for designers
Author Response
Dear Reviewer thank you for your kind and wise comments for the improvement of our draft and enhance the quality of our paper. we have responded to your comments below and modified it in the paper as well.
- Many typos still remains in the revised manuscript.
Response: Thank you for bringing this to our attention; the authors have updated the draft.
- Table 2 observations looks incorrect, need to revisit.
Response: Thanks for your comment. The authors have presented only key summary in this table and the authors attempt to stay concise. Please note that this is a review, not a research article.
- Line 215 to 218, Please rephrase as they are confusing.
Response: Thank you for bringing this to our attention; the paragraph has been revised the text accordingly.
- Line 239 to 242, introducing irreversibility vs R410A looks abrupt, need to rephrase and state the conditions of observations.
Response: The authors have now revised the manuscript. Before selecting a refrigerant, the energy input to the compressor, systemic irreversibility, and the condenser duty are important considerations to the authors of “Shen, B. and M. R. Ally (2020). "Energy and Exergy Analysis of Low-Global Warming Potential Refrigerants as Replacement for R410A in Two-Speed Heat Pumps for Cold Climates." Energies 13(21): 5666.”.
- Fig 12 can be divided in three subsets, not readable in current format.
Response: The authors had already converged from three different figures presented in the paper (Evaporation heat transfer of the low GWP alternative refrigerants (R-448A, R-449A, R-455A, R-454C) for R-404A in a micro-fin tube." International Journal of Refrigeration 128: 118-128.). Please take into consideration that this is a review article, which means that a more comprehensive understanding of the relevant research is prioritized.
- Table 3, Kim C, H and Kim N, H, is same as (67)?
Response: Kim C, H and Kim N, H, have published two different papers (i.e., “Kim, C.-H. and N.-H. Kim (2021). "Evaporation heat transfer of the low GWP alternative refrigerants (R-448A, R-449A, R-455A, R-454C) for R-404A in a micro-fin tube." International Journal of Refrigeration 128: 118-128.” and “Kim, C.-H. and N.-H. Kim (2022). "Evaporation heat transfer and pressure drop of low GWP R-404A alternative refrigerants in a multiport tube." International Journal of Heat and Mass Transfer 184: 122386.”) with the same geometry that’s why the authors mentioned “is same as (67)”.
- Table 5, geometries of BPHE not clear, information is not consistent, suggestion to revise the Table and provide details of BPHE in a structured format
Response: The draft has been changed in response to your suggestions, which the authors really appreciate.
- Line 538 to 539, High speed Vapor...? Need to explain in detail the reason.
Response: Here the term high speed refers to the frequency of the vapor flow. A tremendous number of liquid droplets are produced when a fast-moving vapor flows through a sophisticated chevron structure.
- Conclusion still do not have heat fluxes and mass fluxes ranges for which the review has been conducted, this would be very helpful for designers.
Response: For the convenience of designers, the authors have properly and succinctly outlined in the corresponding tables all the working conditions, including heat fluxes, mass fluxes, saturation temperature ranges, and the geometric characteristics of the heat exchangers.
Author Response File: Author Response.pdf
