Review Reports

Round 1

Reviewer 1 Report

The aim of this work is to evaluate the IEQ performance of a two-sided windcatcher fitted with anti short circuit device (ASCD) to improve its performance in low wind speeds. The 3D steady Reynolds-Averaged Navier-Stokes (RANS) simulations were performed using the commercial CFD software, ANSYS Fluent. The Standard k-e model was chosen for the calculations.

The topic of the work is very interesting and current, but I still have some critical comments:

• In chapter 2 (line 98) is stated: The computational model will be validated by comparing the simulation results with wind tunnel experiment data. The only comparison is in the supply and exhaust airflow velocity (Subchapter 3.1, Fig. 4 and 5), where specific experimental data were taken from the literature [24]. I do not see further verification of the results in the presented work. If they are, they should be highlighted with reference to resources. If they are not, it must be admitted that in the following points of the study it is only a CFD analysis. It is also necessary to justify why the authors consider only this comparison with the experiment to be sufficient.
• In subchapters 2.3 Mesh generation and1. Validation and grid adoption of CFD simulation. For better orientation, I consider the description and the scheme to be slightly confusing. I recommend at least adding the number of elements for fine, medium and coarse mesh in the text (line 208) and in Figure 6.
• As mentioned above, from Subchapter 3.2 onwards, it should be noted that this is only a CFD analysis.
• Conclusions and Future Works, line 414: you should provide relevant information on the verified results and explain why only these presented comparisons are considered sufficient.

Formal comments:

• Subchapter a 2.2. Solver Settings: fix numbering
• 9: unify the units in Figure and its description
• From Fig 12 onwards correct the numbering of all figures
• Line 341: fix Error references

Comments for author File: Comments.pdf

Author Response

The authors would like to thank the reviewer for the comments and suggestions. The comments and suggestions were very helpful. We have implemented all of them and believe that our work has improved significantly. See enclosed the response to review comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript describes the results of a parametric numerical study of fluid flow and heat transfer of anti short circuit device (ASCD) configuration fitted in a two-sided windcatcher fitted subjected to different wind speed and direction. These numerical predictions are used to evaluate the Indoor environmental quality (IEQ) provided by the device. The CFD results are validated with experimental data collected in a wind tunnel facility. Numerical predictions indicate that a 45° incident angle of the ASCD provides better results in terms of fresh air supply rate and specific air change rates.

In general, the manuscript is clear and its references are fully adequate. A minor revision is needed to improve the manuscript and increase its clearness:

p.2, l.53: text should not be broken

p.3, l.115. It was buoyancy considered? How the state equation was implemented?

p.5, l.154. Describe convergence criteria per scalar and vector parameter. What were the residuals when solution converged?

p.7, l.208. The mesh size should not be evaluated also inside the windcatcher model with ASCD?

p.10, Fig.9. What configuration provides better results, ASCD with 15cm or 20cm? From the analysis of Fig.9, it seems that 20cm provides better results. If yes, why 15cm ASCD was chosen for further studies?

p.11, Fig. 10. A vertical centered velocity plane comparing the results presented in Fig.9 should be included.

p.12, Fig. 11. A horizontal centered velocity plane comparing the results presented in Fig.11 should be included.

p.13, Fig 2. It is Figure 12

p.14, Fig.3. It is Figure 13

p.15, Fig.4. It is Figure 14

p.15, l.337. “14” is lacking after “Figure”

p.15, l.306. Reference source error. Correct

p.16, Fig.5. It is Figure 15

p.15, Fig. 15. A vertical centered velocity plane comparing the results presented in Fig.15 should be included.

p.17, Fig.6. It is Figure 16

p.17, Fig.7. It is Figure 17

p.19,l.411. Authors state that ventilation performance of the windcatcher in 45° wind incident angle was improved as compared to the 0° wind incident angle. But how can authors control wind incident angle?

Author Response

The authors would like to thank the reviewer for the comments and suggestions. The comments and suggestions were very helpful. We have implemented all of them and believe that our work has improved significantly. See enclosed the response to review comments.

Author Response File: Author Response.pdf

Reviewer 3 Report

Scientifically, this study appears to be well-done and appropriate, however there seems to be a large number of errors regarding the figures and a few other typos:

Several references to figures in the text of the document are missing figure numbers: Lines 263, 278 and 337 are just a few spots where I noticed this. Line 291 references figure 2, but there are two figure 2's? Needs to be addressed.

The figure numbering appears to start over midway through the document, needs to be fixed to avoid duplicate figure numbers

Bar graphs on p.14 are quite blurry

Each bar graph appears to have a different format and style? Paper would be improved by unifying the styles in some way

Line 53 starts a new paragraph in the middle of a sentence

Beyond formatting/typo concerns I do have two scientific questions for the authors:

1) In Fig. 8, the 15cm ASCD has a smaller stagnation (low velocity) region on the outlet side of the room (circled), but there does appear to be more stagnation of the inlet side of the room (uncircled). Do the authors account for both sides of the room when choosing the 15cm ASCD over other ASCD designs?

2) In Fig. 10, it appears that the short-circuiting may be affected by wind speed, is this true? How does the choice of windspeed affect the optimum ASCD length? Why was the wind speed in Fig. 8 chosen for selecting the optimum ASCD geometry?

Overall, this paper is interesting and well-explained, but that is undercut by some of the figure sloppiness.

 

Author Response

The authors would like to thank the reviewer for the comments and suggestions. The comments and suggestions were very helpful. We have implemented all of them and believe that our work has improved significantly. See enclosed the response to review comments.

Author Response File: Author Response.pdf