Evaluation of the Thermal Performance and Energy Efficiency of CRAC Equipment through Mathematical Modeling Using a New Index COP WEUED

Round 1

Reviewer 1 Report

It is reported an accurate evaluation of the

Thermal performances of CRAC.

It is established a method  to do it.

The paper is for some aspect interesting, moreover I suggest that the

Author must add in the conclusion or in the introduction the

Following discussion.

The main item is to remark that the problem of the thermal efficiency

could be improved  if the power dissipation in the computer is reduced.

Moreover they have remarks new ideas and innovative systems to do it, for example

devices based on microfluids components.

I therefore suggest to include some references about one of these should be:

Experimental Thermal and Fluid ScienceVolume 76, Pages 34 - 44September 01, 2016

Experimental study on the slug flow in a serpentine microchannel

• Cairone F.,
• Gagliano S.,
• Bucolo M.

Author Response

Response to Editor:

We would like to thank the Editor and Reviewers for carefully examining our work and for providing us with the opportunity of revising and improving the manuscript. We have addressed all the comments and suggestions of Reviewers and modified the paper accordingly. All modifications are marked in blue colour in the revised manuscript in order to facilitate the review process. Thank you very much. The improvements made in the paper are listed below.

Please see below our detailed responses to every single comment raised. The authors are thanking again for the attention given to this work, we look forward to hearing from you soon.

Yours sincerely,

The Authors

Reviewer 1/Comment 1: It is reported an accurate evaluation of the thermal performances of CRAC.

It is established a method to do it.

The paper is for some aspect interesting, moreover I suggest that the author must add in the conclusion or in the introduction the following discussion.

The main item is to remark that the problem of the thermal efficiency could be improved if the power dissipation in the computer is reduced. Moreover they have remarks new ideas and innovative systems to do it, for example devices based on microfluids components.

I therefore suggest to include some references about one of these should be:

Cairone, F., Gagliano, S., Bucolo, M. Experimental study on the slug flow in a serpentine microchannel. Experimental Thermal and Fluid Science 2016, 76, 34 – 44.

Answer: The authors of the paper thank you for this comment. Your support significantly strengthened the paper content, We appreciate the reference that was included in our article, and also emphasize the importance of reducing heat dissipation on DCs. (see lines 289 to 295).

Reviewer 2 Report

The paper is focused on the s the need for Computer Room Air Conditioning type equipment. The paper is good but some questions could improve the paper.

 

• The relevance to energy related issues should be enhanced. Please note Applied Science is focused on energy related topics with emphasis on application.
• The abstract is not clear. It should answer the questions: What problem did you study and why is it important? What methods did you use? What were your main results? And what conclusions can you draw from your results? Please include in your abstract more specific and quantitative results when it suits broader audiences.
• Explain if the methodology has been validated
• Highlight how this methodology can be useful for further study.
• The analysis section is really poor. Please provide a better description of the results. All data shall be carefully presented with consistent accuracy. Uncertainty of input data/assumptions shall be addressed.

Author Response

Dear Reviewer,

We would like to thank the Reviewer for carefully examining our work and for providing us with the opportunity of revising and improving the manuscript. We have addressed all your comments and suggestions and modified the paper accordingly. All modifications are marked in blue colour in the revised manuscript in order to facilitate the review process. Thank you very much. The improvements made in the paper are listed below.

Please see below our detailed responses to every single comment raised. The authors are thanking again for the attention given to this work, we look forward to hearing from you soon.

Yours sincerely,

The Authors
Reviewer 2/Comment 1: The paper is focused on the s the need for Computer Room Air Conditioning type equipment. The paper is good but some questions could improve the paper.

    The relevance to energy related issues should be enhanced. Please note Applied Science is focused on energy related topics with emphasis on application.

Answer: The authors of the paper thank you for this comment. Your support significantly strengthened the paper content. The main purpose of this article is linked to increasing the adherence of energy efficiency of CRAC equipment with the real world of Data Centers, since the current method stipulates temperatures to test the machines and even choose the most efficient CRAC equipment in situations with less than 5% of the real outdoor temperatures that a Data Center operates. We improved the abstract and followed your suggestions, see Lines 11 to 25.

 

Reviewer 2/Comment 2: The abstract is not clear. It should answer the questions: What problem did you study and why is it important? What methods did you use? What were your main results? And what conclusions can you draw from your results? Please include in your abstract more specific and quantitative results when it suits broader audiences.

Answer: The authors of the paper thank you for this comment. The abstract was changed. The reasons for the new method were better explained, and it was also explained that the current method has less than 5% adherence with the reality of temperatures in the 29 largest cities in the world, leading to an inaccuracy and not benefiting CRAC equipment with variable frequency. (see lines 11 to 25).

 

Reviewer 2/Comment 3: Explain if the methodology has been validated

Answer: The authors of the paper thank you for this comment. For the validation of the method, simulation of Scroll Inverter compressors in Bitzer's software and temperature data from ASHRAE Data Weather Viewer was performed. (see lines 216 to 222).

 

Reviewer 2/Comment 4: Highlight how this methodology can be useful for further study.

Answer: The authors of the paper thank you for this comment. It was addressed how this methodology can be useful for further studies at the conclusion. (see lines 11 to 25).

 

Reviewer 2/Comment 5: The analysis section is really poor. Please provide a better description of the results. All data shall be carefully presented with consistent accuracy. Uncertainty of input data/assumptions shall be addressed.

Answer: The authors of the paper thank you for this comment. The analysis and discussion were better addressed, and the difference between WCOP EUED and the NCOPEUED of São Paulo, for example, was even better explained. (see lines 271 to 282).

Round 2

Reviewer 2 Report

The paper has been improved.