Proposals for Next-Generation Eco-Friendly Non-Flammable Refrigerants for a −100 °C Semiconductor Etching Chiller Based on 4E (Energy, Exergy, Environmental, and Exergoeconomic) Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors, thank you for your high quality work and good presentation.

1. The main question of this paper is effectivness of the eco-friendly non-flammable refrigerants for a 100 °C semiconductor etching chiller.

2. Topic is original.

3. This results gives optimal configurations of conventional MR and eco-friendly MR were identified for use in the CMRC, where the HTC evaporation temperature ranged from .40 °C to .20 °C. This analysis was based on the original methodology of authors which was presented like previous study. Methodology incorporating both energy and exergy analyses. Methodology don’t need corrections.   4. The conclusions are consistent with the evidence. It has answer to the main question.

5. References are appropriate.

Best regards, reviewer

Author Response

Thank you so much for your favourable review of my paper. I have made some changes that other reviewers have suggested, and I hope you will take a look at my paper as well. Thank you again.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Cryogenic etching minimizes chemical reactivity, thereby reducing byproduct formation and enhancing etching rates at temperatures below −70 °C. This technique not only preserves the yield by eliminating the need for separate cleaning processes owing to its non-deposition characteristics but also improves anisotropy when performed at temperatures around −100 °C. To achieve temperatures of −100 °C or lower, a mixed refrigerant (MR) should be used. However, it is challenging to find high-performance MR. Herein, Jung et al. introduced a −100 °C chiller using a mixed refrigerant (MR) with a GWP of 150 or less, aiming to comply with stricter environmental standards and contribute to environmental preservation. Comprehensive analyses—energy, exergy, environmental, and exergoeconomic—were conducted to evaluate the feasibility of replacing conventional refrigerants. The results revealed that using eco-friendly MRs increased the coefficient of performance by 52%, enabling a reduction in compressor size owing to significantly decreased discharge volumes. The reported results are useful to the design of refrigerants for low-temperature control. The manuscript could be published in Energies after some minor revisions.

1.      Lines 140-141, “Most research in this field has focused” should be corrected to “Most researches in this field have focused”.

2.      The corresponding relation of natural numbers in Figures 1 and 2 should be illustrated in the captions of the figures.

3.      Lines 301-302, “T_0 = 25°C and P_0 = 101.325 kPa” should be corrected to “T0=25℃ and P0=101.325 kPa” where “0” is a subscript.

4.      Lines 390-391, “〖∆T〗 _LMTD” should be corrected to “∆TLMTD” where “LMTD” should be a subscript.

5.      In Conclusion Section, the authors should clearly disclaim what is the proposed eco-friendly non-flammable MR. What is the optimized composition of the proposed eco-friendly MR due to that it is a mixture of two or more refrigerants?

6.      Cases 5 to 8 represent eco-friendly MR. After 4E analyese, which case would be recommend for the semiconductor application working under temperatures lower than -100℃? In other words, the investigation target should be pinpointed.

7.      Line 688, “4” and “2” in “CH4/H2/Ar” should be subscripts.

8.      In Refs. 7, 9, 25 and 28, “2” in “CO2” should be a subscript.

9.      In Ref. 32, “2” in “N2O/CO2-Mixtures” should be subscripts.

10.   Please read the manuscript carefully and make a revision to assure the sentences in the main text are concise and clear.

Comments on the Quality of English Language

The quality of English Language should be improved to avoid grammar errors and make the sentences concise and clear.

Author Response

First of all, thank you for your in-depth advice on the paper. In order to improve the quality of the paper, everything that Reviewer 2 said was fully reflected in the text. We've prepared a PDF file to reflect your suggestions. Please check the PDF file.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript, titled “Proposals for Next-Generation Eco-Friendly Non-Flammable Refrigerants for a −100 °C Semiconductor Etching Chiller Based on 4E (Energy, Exergy, Environmental, and Exergoeconomic) Analysis”, explores the potential for integrating eco-friendly refrigerants into semiconductor cryogenic etching processes. It emphasizes the feasibility of using the proposed mixed refrigerants as alternatives to conventional refrigerants through a comprehensive 4E analysis—focusing on energy, exergy, environmental, and exergoeconomic aspects.

Dear Authors,

1.             The paper is relevant to the scope of the journal.

2.             The writing quality is sufficiently high.

3.             The title of the paper reflects sufficiently and clearly the topic.

4.             The abstract contains a sufficient summary of the work.

5.             The introduction presents the relevancy of the topic, and clear objectives.

6.             The analysis and model are clearly presented.

7.             The illustrations and tables are informative, well-presented, and needed.

8.             The writing style is sufficiently clear and concise.

9.             The manuscript's length is commensurate with the information conveyed.

This paper proposes a great concept that the industry really needs. It is also very well written. However, there are some gaps that I believe need to be addressed before publication.

1.              The authors should emphasize in the abstract and conclusion that the results have been obtained from a simulation model.

2.             Section 1: Introduction is too lengthy. Please divide it into two subsections: (i) Literature Review, and (ii) Research Gap, Novelty, and Paper Structure.

3.             The term eco-friendly refrigerant should be defined and explained in more detail to provide clearer context.

4.             The authors should pay attention to the typo mistake like CO2 instead of CO₂

5.             The clarity and conciseness of Section 1 should be enhanced. The research gaps and novelties need improvement and should be presented in a bullet-point or list format for better readability.

6.             The structure of the paper should be briefly outlined at the end of Section 1.

7.             The paper lacks a Methodology Section, which makes the overall logic less clear. A subsection should be added before Section 2 to clarify the research methodology and the relationship between the sections.

8.             Section 2 should be improved by ensuring that figures are introduced first in the text before being presented in the paper.

9.             It would be beneficial if the authors described the characteristics of CMRC components used in the simulation model in a table format for clarity.

10.         The creation of the Thermodynamic Model in Section 4 is a core part of the study. It is recommended that a flowchart be added to describe the modeling process in detail.

11.         Table 8 in Section 5 is not clearly presented. Please improve its clarity.

12.         The mixing ratio of the refrigerants in Table 8 is not defined. Are the Refrigerants mixed in equal ratios? Additionally, thermophysical properties, NBP, ASHRAE safety group, and ODP of the new mixed refrigerants mentioned in the table should be specified.

13.         In section 6, the terms case 4-1 and case 7-1 are used. Please clarify what these terms represent, are they representing case 4 and case 7 or what.

14.         The authors noted that this paper replicates the methodology adopted in [31]. Can the novelty of this paper be highlighted in relation to [31]? Is the only difference the study of eco-friendly refrigerants? The authors should also assess and compare the findings of the previous paper with the results in this study.

15.         The limitations of the study should be discussed in the Conclusion.

I recommend a "Major Revision" for the manuscript and hope to read an improved version in the foreseeable future.

Comments on the Quality of English Language

The writing quality is sufficiently high and writing style is sufficiently clear and concise

Author Response

First of all, thank you for your in-depth advice on the paper. In order to improve the quality of the paper, everything that Reviewer 3 said was fully reflected in the text. We've prepared a PDF file to reflect your suggestions. Please check the PDF file.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have taken all the suggested recommendations into consideration, and these have been fully incorporated into the text to enhance the quality of the paper.

Dear Authors,

1. The paper is relevant to the scope of the journal.
2. The writing quality is sufficiently high.
3. The title of the paper clearly and accurately reflects the topic.
4. The abstract provides an adequate summary of the work.
5. The introduction effectively highlights the relevance of the topic and sets clear objectives.
6. The analysis and model are presented clearly.
7. The illustrations and tables are informative, well-presented, and essential.
8. The writing style is clear and concise.
9. The length of the manuscript is appropriate for the content presented.

This paper proposes a valuable concept that the industry truly needs. It is also very well written. The authors have successfully addressed all the gaps in the previous version of the manuscript.
I recommend accepting the revised manuscript without any further revisions.