Assessment of Aircraft Surface Heat Exchanger Potential
Round 1
Reviewer 1 Report
This paper describes a first-order analysis of the potential of using the surface of an aircraft for cooling of the internal heat load. It concludes that it may be possible to dissipate enough heat, presuming that the aircraft surface can be kept uniformly at a temperature of ~370K.
This paper does a good job considering the relevant features, providing assumptions of the model, and examining its sensitivities. I am now left wondering how much loss in potential due to actual heat exchanger implementation would be typical, and encourage the authors to take a brief foray there (estimate expected effectiveness, estimate expected weight increase assuming state of the art high effectiveness compact HEX) to make the study more complete.
However, this is a well-written study that is easy to follow and provides good analysis for the first-order potential. I have no required changes.
Please correct some typos (see the attachment).
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer
Thank you for the review of our work. We corrected all the typos highlighted by you and also screened the entire work for additional ones.
We agree with your comment that a more detailed analysis of the surface cooler would be necessary to quantify the impact on aircraft level. However we are of the opinion that a quick estimation would not do this rather complex topic justice. As mentioned in our outlook we would like to compare different solutions for the thermal management system to each other to evaluate their advantages and disadvantages and identify a possibly superior candidate on aircraft level. The modeling of a conventional TMS with a compact heat exchanger for heat loads of this magnitude has to be done carefully. Instead of a quick estimation, we would prefer to dedicate more time to it and publish well-reasoned results with comprehensive modeling depth. This will allow a fair comparison of the weight of a surface cooling system and a conventional cooling system. Therefore, the focus of this work is solely on the question whether a TMS employing surface heat exchangers can actually provide the required cooling power and leave the optimization and comparison on aircraft level for future work.
Best regards
Hagen Kellermann
Reviewer 2 Report
Dear Authors,
Many thanks for your good paper. I really found your paper interesting. It has a very good structure and all aspects have been investigated carefully. This paper contains enough results regarding numerical simulations. Maybe some minor revision is needed for some typos.
Author Response
Dear reviewer
Thank you for the revision of our work. We screened the entire document for typos and corrected everything that we found.
Best regards
Hagen Kellermann
