Optimization of the Beef Drying Process in a Heat Pump Chamber Dryer
Round 1
Reviewer 1 Report
Paper Code: Energies-1328734
Paper Title: Optimization of the beef drying process in a heat pump chamber dryer
The authors have presented a numerical study aiming to optimize the drying process of beef in a heat pump convection chamber dryer. According to the authors, a critical analysis of the drying literature has indicated that the optimization could be achieved by upgrading a standard heat pump drying chamber.
Table 1 presents important modifications that enable computer simulations of the drying medium flows with the Ansys software (i.e. the drying chamber under test has been modified as shown in Table 1).
The main conclusions of the present manuscript have revealed that (i) in drying chambers used in beef processing technologies, non-uniform distribution of drying medium streams has conducted to non-uniform degree of meat drying, which present dependency on the placement in the drying chamber; (ii) CFD simulations have enabled optimization of the drying process through identification of possible modifications to the design of the drying chamber; and (iii) CFD simulation in chamber 5 has showed a significant improvement in meat drying, both in terms of activity and water content after 10 hours of the process.
The work is reasonably well organized and well written. In my opinion, the manuscript could be published as Energies’ paper after attending the following revision:
(i) It is unclear into the Abstract the main contribution/originality of the present work. The readers will be beneficiated with that information and the paper context will be completed.
(ii) With respect the present numerical approach, in section 1, I would like to recommend a short commentary concerning Lagrangian manner to solve the present problem. I think that is very interesting to point some alternative methodology. Four reference papers, recently published in Energies, can be cited by the authors aiming to enrich their work:
[1] Slama, M.; Choma Bex, C.; Pinon, G.; Togneri, M.; Evans, I. Lagrangian Vortex Computations of a Four Tidal Turbine Array: An Example Based on the NEPTHYD Layout in the Alderney Race. Energies 2021, 14, 3826. https://doi.org/10.3390/en14133826
[2] Choi, S.K.; Choi, Y.S.; Jeong, Y.W.; Han, S.Y.; Nguyen, Q.V. Simulation of the Fast Pyrolysis of Coffee Ground in a Tilted-Slide Reactor. Energies 2020, 13, 6605. https://doi.org/10.3390/en13246605
[3] Oliveira, M.A.d.; Moraes, P.G.d.; Andrade, C.L.d.; Bimbato, A.M.; Alcântara Pereira, L.A. Control and Suppression of Vortex Shedding from a Slightly Rough Circular Cylinder by a Discrete Vortex Method. Energies 2020, 13, 4481. https://doi.org/10.3390/en13174481
(iii) The section 2 makes clear the methodology presented by authors. However, I would like to recommend the inclusion of the main governing equations and boundary conditions, which turn viable the CFD analysis.
(iv) On page 8, line 240, the authors have commented that “… The conducted CFD simulations of streamlines, velocity fields and velocity vectors revealed that there is a large variation of airflow in the unmodified chamber. The greatest variation of the fields occurs in the middle and upper sections of the chamber, where the values of the streamlines, vectors and velocity fields are significantly smaller than in the lower section of the chamber.”
I would like to recommend a complementation concerning that analysis including some physical sense. It is very important to approximate the numerical results with the associated physics. The results are very interesting!
(v) Another recommendation. On page 8, line 244, the authors have also commented that “… CFD simulations have demonstrated that the proposed modifications 4 and 5 can beneficially affect the drying process. For these solutions, the calculated distributions of streamlines, velocity vectors and velocity fields in the entire chamber are more uniform compared to the calculated distributions in the unmodified chamber. Based on the CFD simulations performed, the chamber was upgraded to be structurally identical to the chamber used in simulations 4 and 5.”
I think those three sentences can be supported by interpretations of the associated physical phenomenon.
(vi) Please, on page 10, lines 284 and 289, “Table 1” must be replaced by “Table 2”
(vii) Please, starting page 11, line 292, the titles “Chart 1” until “Chart 14” must be replaced by “Figure 9” until “Figure 23”. All figures need presentation/analysis/interpretation into the manuscript. The manuscript must contain 23 figures numbered from Figure 1 until Figure 23.
(viii) On page 17, line 359, the word “chamber V” must be written as “chamber 5”. Please, revise that situation along all manuscript.
(ix) There are various words written in orange into the manuscript. Why? I would like to recommend an extensive revision in all parts of the manuscript (please, see on page 12, lines 304-305 and lines 314-315).
(x) In section 4, the authors have provided satisfactory conclusions about their research. However, it is important to clarify the main contribution of the present research for the specialized literature. Are there suggestions for future work? It is important to finish the section 4 with new perspectives for the work.
Author Response
The Authors want to thank for all suggestions that have enriched the manuscript. All modifications and responses are presented in green (in text) as well as the answers for each question.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The presented article deals with the issue of optimizing the meat drying process. This method of meat processing is known and in the past was one of the few options for preserving and storing meat. The process took place in natural weather conditions. At present, such a method is unsuitable, mainly due to hygienic requirements, and industrial drying is preferred, which guarantees the quantity and also the quality of the dried meat, while maintaining hygienic standards.
The authors could provide more detailed information on the simulation process.
The parameters of meat drying over time, in individual zones of the drying device, were quantified. The measurement methodology was chosen correctly and allows you to repeat the experiment and verify the results. The proposed modification of the device made it possible to achieve uniform drying, which was also confirmed by experimental measurements.
The last chapter, the conclusions, presents the 3 main benefits of the article. This chapter is very short and concise. It might be appropriate to add some comparison with other authors who have tackled a similar problem.
Please, add some more informations about numerical simulation – for example used mesh, mesh quality, size etc.
Please add some informations about modification nr. 5 – You mentioned the rotating disc, but there are only few informations in the text, how was this simulated and how this contributed to changing flow characteristics.
Chart 2, 3 – another font color
Please add some more informations, why the 5th modification showed the best results, maybe Your opinion, why is this modification the best and why was the meat uniformly dried.
Author Response
The Authors want to thank for all suggestions that have enriched the manuscript. All modifications and responses are presented in red (in text) as well as the answers for each question.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Paper Code: Energies-1328734-V2
Paper Title: Optimization of the beef drying process in a heat pump chamber dryer
The revised version of the paper addressed most of the questions raised in the review process. It is clear that many comments/corrections were included in the text, which helps the reader to better understand what was done in this research. Also, the issues concerning the methodology/governing equations were clarified and figures/text have been corrected. This kind of research is extremely applicable and the readers/interested will be beneficiated with the work. In my opinion, there is no major objection to the manuscript in its current form, which leads to the recommendation of its publication as Energies ‘paper.
