GIS Retrofitting Technique for Hong Kong Sports Center with a Large Hall
Round 1
Reviewer 1 Report
This paper proposes the Green Air Distribution System (GIS) to reduce energy consumption and optimise the thermal comfort of a large sports centre in Hong Kong to achieve carbon neutrality.
The topic is interesting and in line with the scope of the Journal.
The paper is well organised, findings are discussed, and figures are informative. However, I am not an expert in CFD and cannot assess the reliability of the result. The description of the model is complete, even if I do not see the reason to report the formula if the author has used what is already validated.
The introduction lacks appropriate reference, and a literature review of similar works must be integrated.
The research question must be funded on the analysis of prior work, pointing out the originality of the work.
At this moment, I do not see where this originality lies. Or better this originality is not well documented.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Reviewer 2 Report
- The work takes an interesting perspective, though not very original. The Case study, even though just a numerical simulation, could have been an interesting study. But the way the problem statement, results, and discussions have been presented leave a lot to be desired and means the text requires serious improvements.
- Overall, the English needs to improve a lot, as does the organization. Right now, the work is put together in a very confusing manner and there is lack of continuity. Each paragraph seems tobe its own story.
- The building sector, which accounts for around 90% of electricity consumption and approximately 66% of GHG emissions- these values seem off.
- It is not clear why the supply air temperature could be increased by 1.5 C - why the increase and why specifically 1.5 C
- Grid independence is typically analyzed against a series of continuous increase in cell numbers, not a categorical data like meshing level. This kind of categorical analysis is harder to understand and the plot trends make less sense
There is little coherence in narration.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Reviewer 3 Report
This study used CFD simulations to compare the performance of green air distribution and traditional air distribution in a large space. This study is interesting, and this paper was written well. The results derived from this study can contribute the energy-saving design of air conditioning system in a large space. The detailed comments are as follows.
1. Section 1 Introduction: In this study, only twenty references were cited. This section should provide a comprehensive literature review as a number of previous studies had been conducted to investigate air distribution.
2. Section 2 Methodology: (1) Since a number of indexes were used to evaluate the performances of air distributions, it was suggested to describe these indexes in details; (2) Please the grid numbers for grid-independent analysis.
3. The experimental validation of CFD simulations was lacking. At least, some references should be cited to demonstrate the accuracy of CFD simulations used in this study.
4. An elevation of supply air temperature can result in energy saving. However, energy saving was not quantified. It is suggested to use an index for quantifying the potential of energy saving of GIS system, e.g. energy utilization coefficient.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
thank you for having improved your paper.
Best wishes
Author Response
thank you for having improved your paper.
Thanks for your appreciation of my improved paper.
Reviewer 2 Report
Highlight number 4 is not really a highlight.
Minor English edits still required. Like spelling of Solidworks
One thing the authors are still missing to clarify their system vis a vis something more used like displacement ventilation system.
Some portions of Section 3, like figure 7, belong in Methodology section.
It has improved a lot, some minor corrections needed.
Author Response
Comments and Suggestions for Authors
Highlight number 4 is not really a highlight.
The highlight number 4 is deleted.
Minor English edits still required. Like spelling of Solidworks
The spelling of Solidworks is corrected. The overall English edits are done. The presentation of some contents is improved in readability, such as the description of item 4 “For item 4 in Table 5, the cost-effectiveness study in large space installation is more significant than the small-to-medium application. In this large space study, there is still much research feasibility on the practical consideration of integrating with other ventilation systems to achieve a dual-purpose usage of system components. For example: using the return air duct at the ceiling as the smoke ductwork of the smoke extraction system, which can reduce the installation cost and space to achieve cost-effectiveness results, for example, using dual-purpose ductwork design as mentioned in the above Section 3.3 and illustrated the actual installation in Tai Wan Station in Appendix C. In addition, this GIS can be used during the epidemic by providing more fresh air in the occupied zone.”
One thing the authors are still missing to clarify their system vis a vis something more used like displacement ventilation system.
In large & high spaces, displacement ventilation is best suited in comparison with mixing and stratum ventilation. Mixing ventilation is better suited for smaller spaces where air quality is not as great a concern, such as single-occupant offices, and where the room height is not tall. Stratum ventilation by elevated supply air temperature is suited for small-to-medium-sized spaces without mitigating the thermal comfort at the occupied zone. For sports centers, larger air output is required, and displacement ventilation is hard to control indoor humidity due to the higher supply of air temperature [30&31]. This GIS can take advantage of Stratum and displacement ventilation, as shown in this Sports Center from the above simulation results.
Some portions of Section 3, like figure 7, belong in Methodology section.
Figure 7 moves to Methodology Section and renames it as Figure 1.
Comments on the Quality of English Language
It has improved a lot, some minor corrections needed.
Minor corrections on the quality of the English language are done and highlighted in the attachment for your easy reference.
Overall, English is polished up. Minor corrections are highlighted in the revised paper by “Track Changes.”
Author Response File: Author Response.pdf