A State of the Art Review on Sensible and Latent Heat Thermal Energy Storage Processes in Porous Media: Mesoscopic Simulation

Round 1

Reviewer 1 Report

The paper presents a review of thermal storage systems and their numerical simulations using Lattice Boltzmann method. In my opinion, the quality of the work is not suitable enought to justify its publication. The section on the application of LBM to thermal storage systems is indeed of interest to the readership of Applied Sciences but it is not treated deeply enough. All the first sections present generic information on storage materials that are available in several other publications. In general, it is not clear what the authors want to achieve with this review: in order for it to be interesting, a more thorough description of the equations, the software to be used, the typical application conditions, grid size, advantages and disadvantages over other numerical methods should be given.

Moreover, English needs deep revision. 

Ref. [27] is Cabeza et al, not Gabeza et al, as mentioned multiple times in the manuscript.

Author Response

Please see attached file "Answers-referee#1_paper_Appl. Sci_VHN_April 02, 2022.docx"

Author Response File: Author Response.pdf

Reviewer 2 Report

The present manuscript is a review about thermal energy storage systems coupled with porous media. In particular, the authors gave some emphasis to mesoscopic simulation procedures, with particular references to models derived with approaches based on Lattice-Boltzmann method, Volume-Averaging techniques or pore-scale simulation. The reviewer thinks that this is a very interesting review article, that could be considered for publication only if the following points are addressed by the authors.

• In the abstract and also in the text please avoid double parenthesis as occurs for (PCMs))
• Please check Figure 1 y-axis; are the authors refer to Energy in kWh?
• In Table 2, how did the authors define the efficiencies of these TES techniques? Besides, which is the meaning of kWh/t?
• Please revise typos. For instance, in Table 4 "Kg" should be written as "kg"
• Could the authors provide a better description of the packed bed storage tank depicted in Fig. 7?
• In Figs. 8 and 9, didn't the authors stress the melting temperature range, also known as Tsolidus - Tliquidus? Please report some comments about this aspect, since it is widely known that the melting temperature range is something really important especially for PCM modeling by means of the apparent heat capacity method
• Some more comments about supercooling (Fig. 9) are suggested. PCMs usually present different melting and solidification temperatures; this is not a simple task as it is especially from a predictive point of view.
• 10 looks to be too thin, please expand this in order to stretch text (same thing happens for Fig. 11)
• When describing techniques to improve thermal conduction in phase change materials, the authors forgot to mention that nowadays employing PCM together with both fins and porous structure could be a very interesting solution nowadays [1]. This should be mentioned since the objective of a review is to collect the current state-of-art of a research
• In Table 7, isn't "Heat transfer time" more appropriate than "Heat transmission interval"
• In Table 7, "K" should be "k" for kg and kWh
• It is strongly suggested to have a final check of equations and so on. In Eq. (20), is porosity a multiplier for the Buoyancy term?
• In Eq. 22, did the authors defined the liquid fraction function (from 0 to 1) in the last term on the right side of the equation?
• This is a well-presented review, but from the reviewer's point of view some effort is mandatory from the authors in order to improve subsection 5.4. This is a review article, so it might be a reference for whom wants to discover this particular subject. For instance, it has been shown that natural convection might be negligible in some circumstances in order to simplify the mathematical model [2], which an aspect that should be mention in this review in order to underline how much convection is relevant in modeling. Other aspect that are relevant and should be mentioned here are that pore-scale are well-representative of volume-averaged model if one wants to compute aspects like volume fraction evolution [3], that porosity is the variable with the highest effect compared to other variables like pore density (PPIs), orientation, or gravity.

[1] Bianco, N., Busiello, S., Iasiello, M., & Mauro, G. M. (2021). Finned heat sinks with phase change materials and metal foams: Pareto optimization to address cost and operation time. Applied Thermal Engineering, 197, 117436.

[2] Andreozzi, A., Iasiello, M., & Tucci, C. (2021). Numerical Investigation of a Phase Change Material Including Natural Convection Effects. Energies, 14(2), 348.

[3] Feng, S., Shi, M., Li, Y., & Lu, T. J. (2015). Pore-scale and volume-averaged numerical simulations of melting phase change heat transfer in finned metal foam. International Journal of Heat and Mass Transfer, 90, 838-847.

Comments for author File: Comments.pdf

Author Response

Please see attached file "Answers-referee#2_paper_Appl. Sci_VHN_April 02, 2022.docx"

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper conducted a comprehensive review of sensible and latent heat storage. The paper is interesting and includes valuable results. A minor revision is recommended. The following items need to be addressed before publication.

1. The authors have made a detail description about the LBM method from Eqs. 1 to 18. This part could be simplified as the main MS focus on thermal heat storage method.

Author Response

Please see attached file "Answers-referee#3_paper_Appl. Sci_VHN_April 02, 2022.docx"

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have only partially addressed the comments raised, since they have only slightly extended section 5, but a deep analysis of LBM methods is still missing, as well as a systematic comparison with other methods (e.g. a table summarising the main studies in the literature, the findings, the main features etc). Therefore, the concerns on the novelty and usefulness of such a paper still remain.

Author Response

Answers to the referee#1

We would like to thank referee #1 for once again spending some of their time reviewing the latest version of the manuscript (round 2) and issuing a favourable opinion. Also, we thank the editor for always encouraging the revision of the manuscript.

Again, we took this opportunity to fix the few errors that still inadvertently remained in the text. Also, styling improvements, as well as some clarifications, have been added. Such revision work has been highlighted directly (in light blue) in the current manuscript.

Below, we present, point by point, the responses to the questions and comments raised by the referee#1.

Some responses to comments and corrections or slight edits are provided directly in the revised manuscript and are highlighted in light blue in the revised manuscript.

Note that the letters Q, A and C stand for question, answer and comment respectively.

C1: The authors have only partially addressed the comments raised, since they have only slightly extended section 5, but a deep analysis of LBM methods is still missing, as well as a systematic comparison with other methods (e.g. a table summarizing the main studies in the literature, the findings, the main features etc.). Therefore, the concerns on the novelty and usefulness of such a paper still remain.

A1: We are sorry that our previous answers didn't fully satisfy referre #1. We simply did not fully understand the comment that was made during the first review. Now, we have analyzed and compared the LBM approach while comparing it to classical methods such as the so-called finite volume and finite difference methods (see Section 1, penultimate paragraph, lines 150 to 155 and Section 5, paragraphs 2 and 3, lines 602 to 645 including the Table 8).

We would like to inform the referee that a) 6 new refs. have been added to support our comments, b) from there, the tables, figures and Refs. have been renumbered as appropriate, and c) all contributions have been colored light blue throughout the revised manuscript.

Yours sincerely,

On behalf of my co-authors

1. NAJI, Corresponding author

Univ. Artois, IMT Nord Europe, Junia, Univ. Lille, ULR 4515, Laboratoire de Génie Civil et géo-Environnement (LGCgE), F-62400 Béthune, France.

[email protected]

[1]    Corresponding author.

*Univ. Artois, IMT Nord Europe, Junia, Univ. Lille, ULR 4515, Laboratoire de Génie Civil et géo-Environnement (LGCgE), F-62400 Béthune, France.

E-mail address:[email protected]

ORCID iD:https://orcid.org/0000-0002-5994-7958

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper can be accepted as it is

Author Response

Answers to the referee#2

We would like to thank referee #2 for once again spending some of their time reviewing the latest version of the manuscript (round 2) and issuing a favourable opinion. Also, we thank the editor for always encouraging the revision of the manuscript.

Again, we took this opportunity to fix the few errors that still inadvertently remained in the text. Also, styling improvements, as well as some clarifications, have been added. Such revision work has been highlighted directly (in light blue) in the current manuscript.

Below, we present, point by point, the responses to the questions and comments raised by the referee#2.

Some responses to comments and corrections or slight edits are provided directly in the revised manuscript and are highlighted in light blue in the revised manuscript.

Note that the letters Q, A and C stand for question, answer and comment respectively.

C1: The paper can be accepted as it is.

A1: We are very grateful to the referee for being fully satisfied with our revised manuscript from its first review (round 1) and for recommending it for publication as it was.

Yours sincerely,

On behalf of my co-authors

NAJI, Corresponding author

Univ. Artois, IMT Nord Europe, Junia, Univ. Lille, ULR 4515, Laboratoire de Génie Civil et géo-Environnement (LGCgE), F-62400 Béthune, France.

E-mail address: [email protected]

[1]    Corresponding author.

*Univ. Artois, IMT Nord Europe, Junia, Univ. Lille, ULR 4515, Laboratoire de Génie Civil et géo-Environnement (LGCgE), F-62400 Béthune, France.

E-mail address:[email protected]

ORCID iD:https://orcid.org/0000-0002-5994-7958

Author Response File: Author Response.pdf