Coupling Computational Fluid Dynamics and EnergyPlus to Optimize Energy Consumption and Comfort in Air Column Ventilation at a Tall High-Speed Rail Station
Round 1
Reviewer 1 Report
In this research, the EnergyPlus and CFD simulation coupling method was employed to investigate three ventilation schemes, side jet ventilation, column attached with side jet ventilation for the waiting hall of a high-speed railway station in Guangzhou. The research focused on analyzing the airflow characteristics, thermal comfort, and cooling energy consumption associated with each ventilation method. Comments can be found below,
1. There are numerous researches before, the novelty of this study should be further emphasized in the abstract, introduction and conclusion part.
2. What are the original works in the aspect of EnergyPlus and Fluent, or just adopting these softwares?
3. Thermal comfort indicators of Eq. 1 and 2 should be evaluated and explained in detail.
4. The numerical methods should be verified by comparing with the experimental data and the existing theoretical works, not only compare the results, the discrepancy in Fig. 7 should be described.
5. The air temperature distribution cloud in Figs. 10 and 11 are very low quality and meaningless, the authors should modify them to a large extent.
6. The main body of the article always describes the data, but rarely explains why the phenomenon occurs. Modifications are recommended.
Extensive editing of English language required
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this research, the EnergyPlus and CFD simulation coupling method was employed to investigate three ventilation schemes (column attached ventilation (CAV), side jet ventilation (SJV), column attached with side jet ventilation (CASJV)) for the waiting hall of a high-speed railway station in Guangzhou. It is found that the CASJV is more suitable for application in high-speed railway station waiting hall by analyzing the airflow characteristics, thermal comfort, and cooling energy consumption. However, the research method, the data analysis, and the conclusion are needed to be improved. Here are the detailed comments:
1. The results showed that the cooling energy conversation of CAV and CASJV is 11.89% and 9.25%, respectively, compared with SJV. So, how to get the conclusion that the CASJV is more suitable for application in high-speed railway station waiting hall?
2. Actually, the EnergyPlus and CFD simulation was not enough coupled in this study. The CFD model was simulated only at 16:00 of a typical day in the hottest moth of summer. Therefore, it is suggested to modify the Title of paper and the relevant statements in the text.
3. It is suggested to give the reference basis for these boundary conditions in Table 2.
4. What is the unit of LPD in Table 5, 1% or 1? and, why the difference between LPD1 and LPD2 is so big in Table 5?
Minor editing of English language required.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The authors have presented their research effectively. However, to further enhance the manuscript's clarity and impact, I recommend addressing the following concerns. Once these aspects are appropriately revised, the paper has the potential to be accepted for publication.
1. Title: Please shorten it slightly and avoid including "research on." Since this is a research article, it is already understood.
2. Section 2.3: Please provide more references, particularly for equations 1 and 2. Some terms are confusing, such as "airflow rate" which appears to refer to velocity. Similarly, what does "local" mean in some of the parameters? Is it an average value over the domain? While it's the author's choice, using "t" to denote temperature instead of the conventional "T" could be confusing. Also, both LPD1 and LPD2 denote the "local dissatisfaction rate." What does LPD stand for, and why are they different if they convey the same thing? I recommend revising and simplifying lines 160-163 for better clarity.
3. Please correct the typo: In lines 153 and 154, the abbreviation is LPD2, while it's written as "LDP2" in lines 159 and 162.
4. Please change the caption for Table 2.
5. Suggestion: Briefly discuss mesh independence, mesh quality, and Y+ values instead of dedicating a whole subsection solely to mesh independence.
6. In line 301, remove the hyperlink (underlined text).
7. Consider merging the "Results and Discussion" sections and add the "Conclusion" section.
8. For Figure 9, provide separate subsections for both parts "a" and "b."
9. The results (Turbulence intensity, LPD1) for CAV at the foot (ankle) differ significantly (by 40% or more) from the other two cases, as shown in Table 5. Please explain the physical phenomenon behind these results and provide reasoning to support them. Integrate this discussion into lines 168-170.
10. Suggestion: Include additional contours, velocity streamlines, and diverse results for radiation and convection. Provide details about how natural convection was modeled and the approach used for modeling Radiation losses. Given the CFD analysis performed, maximize the insights obtained from it.
Minor changes are required.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
In this paper, the coupling method of Energyplus and CFD simulation was used to study the airflow characteristics, thermal comfort and cooling energy consumption of a high speed railway station waiting hall in Guangzhou under three ventilation schemes: CAV, SJV and CASJV. There are some defects and problems in the paper, which need to be paid attention to by the author. The main problems are as follows:
1. Chapter numbering is repeated in the article. There are two third chapters in the article.
2.It is pointed out in the abstract that the coupling method of Energyplus and CFD simulation is used to study the waiting hall of a high-speed railway station in Guangzhou. However, the method combining BEM and CFD simulation is used in the introduction.What is the explanation?
3.Partial improvements were made to the CFD modeling in the paper. Please add detailed improvements.
4.In order to compare the differences between the three ventilation modes in air distribution and cooling energy consumption, the wind speed of each ventilation mode was adjusted, so that the active area showed the same temperature distribution characteristics. However, adjusting the wind speed will affect the hourly ventilation volume of each scheme, which may affect the calculation result of refrigeration energy consumption. How does the author deal with the above problems?
5.Refrigeration energy consumption is related to thermal conductivity, the correlation coefficient is not given in the paper, and the numerical simulation parameters need more detailed information, please list the simulation parameters in detail.
6.The expression of Figure 9 in the paper is not clear, the meaning of Figure 9 (b) and the content expressed are not explained in detail, and the author does not give the position of the stratified cloud map of temperature in Figure 10.
7.The local evaluation in the paper pointed out that there was a temperature difference between the head and the ankle in the three schemes, and all the changes were less than 3°C, which was inconsistent with Table 5.
8.In the calculation of refrigeration energy consumption, it is pointed out that the refrigeration energy consumption of SJV is significantly higher than that of the other two ventilation modes during the periods of 0:00-10:00 and 20:00-24:00. This is due to the lower temperature in the non-air-conditioned areas of SJV, resulting in correspondingly higher cooling energy consumption. What is the explanation?
9.In the numerical simulation verification, no ventilation scheme was specified, and the flow field in the area attached to the ventilation column changed along the height of the ventilation column, the author did not provide the basis and location for the value of the wind speed.
10. In this paper, SST K-ω turbulence model was used for numerical simulation. Did the author consider the influence of different turbulence intensity on air distribution, thermal comfort and cooling energy consumption of the waiting hall?
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The comments have been replied properly.
Reviewer 2 Report
All the comments have been addressed.
Reviewer 4 Report
The author has provided thoughtful and detailed replies to the comments put forward by the reviewers, and has revised the article. The revised article is obviously clearer and more complete.
