Exploring the Benefits and Limitations of Digital Twin Technology in Building Energy

Reviewer’s comments

Authors’ Reply

Section 1.2 has many repeat paragraphs, which shall be removed.

Thank you for bringing the issue in the article, we have already deleted this repetitive content.

Table 1 & 2 shows a lot of effort from the authors’ side. But the discussion following them is not very well organized. Few suggestions for the same,

a)       Time-line-based listing

b)      Outcome-based grouping

c)       Process-based categorisation etc.

After discussion, we decided to adopt your suggestion on organizing the table by time.

The discussions in Section 5.1 need further improvement so that a few observations can be the outcome of this section; this section currently lacks the review comments and any guided sequence.

Thank you for your suggestions for section 5.1. You mentioned that you would like to see more observations and conclusions in that section, as well as a review of the comments and a guided sequence. I recognise that there may be some problems with the organisation and clarity of this section and that improvements need to be made. However, given the multitude of energy analysis software included in section 5.1, and the fact that each study subject has a different purpose, there is a real difficulty in developing a clear categorisation.

Our original intention was to provide tabular information so that readers could quickly find the application areas they are interested in. Therefore, in our categorisation of section 5.1, we have mainly classified the different software in terms of their energy application areas, with a special emphasis on Energy Plus because of its wide applicability. Thank you again for your valuable suggestions, which have helped me to improve the article.

Section 5.2 is a comparative more organized, though it also has enough scope to improve.

We appreciate your suggestions for Section 5.2. However, after careful consideration, we believe that the existing structure best supports the coherence and objectives of the study. We therefore intend to maintain the section as it currently stands.

At the present state, to keep alive readers' interest in informative observations is difficult.

We understand your concern about the length potentially detracting from the reader's interest, primarily in sections 5.1 and 5.2, we've endeavoured to condense these sections.

Reviewer’s comments

Authors’ Reply

The authors need to improve the abstract. Therefore, the abstract should answer these questions about your manuscript: What was done? Why did you do it? What did you find? Why are these findings useful and important? Answering these questions lets readers know the most important points about your study and helps them decide whether they want to read the rest of the paper. Make sure you follow the proper journal manuscript formatting guidelines when preparing your abstract.

Thank you for your reviewing. We have thoroughly compared these questions with our abstract, and we believe that our abstract already encompasses the answers to these inquiries.

The introduction section needs improvement. It is important to clearly state the following aspects in the introduction:

*       The main research questions

*       Hypothesis, if applicable

*       Main objective of the study

*       Gap in the literature that this study aims to address

*       Motivation behind the research

*       Relevance and significance of the topic

*       Innovations and novel contributions of the study compared to existing work

*       Unique contribution of this study to the field of investigation.

Thank you for your feedback and suggestions. We have carefully reviewed it based on your advice and made the corresponding adjustments. We hope that this revised version meets with your satisfaction.

The method section could benefit from further improvement. It is important to provide a clear justification for the methodology approach used, explaining why it was chosen and how it is appropriate for the research question at hand. Additionally, it would be helpful to reference prior studies that have successfully used this methodology approach to strengthen the argument for its use in this particular study.

- The data section requires improvement. The authors must address several key questions to provide a better understanding of their approach. Specifically, why were these variables selected for the model? What does the existing literature say about these variables? Additionally, it's important to provide information on previous authors who have used these variables. Without this information, readers may find it difficult to fully comprehend the approach and results presented in te study.

We have revised the methodology section as per your suggestions, providing clearer justifications for our approach and referencing prior studies that have used similar methodology. Furthermore, we have expanded the data section to explain the selection of variables, their significance in existing literature, and previous studies that utilized them.

section of Digital Twin Technology for energy sector development. Although the section is well-structured and well-organized, the novelty of this paper should be further justified by highlighting main contributions to the existing introduction and literature review. This could be clearly presented in your related work. in the table 1 [line 472, page 11-13], and table 2 [line 1052, page 23-25], Please consider citing following papers entitled “Forecasting Energy Demand in China and India: Using Single-linear, Hybrid-linear, and Non-linear Time Series Forecast Techniques”, and entitled“Forecasting US Shale Gas Monthly Production Using a Hybrid ARIMA and Metabolic Nonlinear Grey Model”, next entitled “Uncovering the impact of the COVID-19 pandemic on energy consumption: New insight from difference between pandemic-free scenario and actual electricity consumption in China”, and entitled “Does urbanization redefine the environmental Kuznets curve? An empirical analysis of 134 Countries”, and entitled “Modeling carbon emission trajectory of China, US, and India”, and entitled “, and entitled “The impact of the COVID-19 pandemic on the energy market–A comparative relationship between oil and coal”. There has already been a large number of literatures related to your research. Therefore, it should be better elaborate the contribution of the work to the existing literature, so as to further bridge the gaps between the research background and research purposes.

Thank you for your valuable suggestions and for providing relevant literature. We have improved the thesis and introduced the literature you recommended to strengthen the theoretical basis of the study. These literatures have certainly provided a broader context and deeper understanding of our study.

section of Challenges and Future Directions. Please make sure your conclusions' section underscore the scientific value added of your paper, and/or the applicability of your findings/results, as indicated previously. Basically, you should enhance your contributions, limitations, underscore the scientific value added of your paper, and/or the applicability of your findings/results and future study in this session.

The conclusion part is updated with a more detailed description regarding Challenges and Future Directions.

There are still some occasional grammar errors through the revised manuscript especially the article ''the'', ''a'' and ''an'' is missing in many places, please make a spellchecking in addition to these minor issues. In addition, some sentences are too long to be easy to read. It is recommended to change to short sentences, which are easier to read.

Thank you for pointing out the grammatical problems in our paper. We have double-checked and fixed the grammatical errors throughout the paper.

References. Please check the references in the text and the list; You should update the reference. Please read the latest published papers carefully and format your references according to the format required by the Applied Sciences (SCI Q2 journal). If this revised paper is sent to me for re-review, the first thing I will check the references.

we'll go through again the references thoroughly and update if necessary– we understand how crucial this is. Thanks!

Reviewer’s comments

Authors’ Reply

Digital Twins and BIM are not new, but their applications are limited. I am glad to see a paper which describe the details of their possible applications. In fact, the paper would be of immense interest to the practical engineers. I therefore recommend it to be published. The review is also extensive. 

Thank you for your positive feedback and recommendation for publication; we appreciate your recognition of the paper's detailed applications and extensive review, which will indeed be of great interest to practical engineers.

The paper is quite easy to read and with only few grammatical errors.

Thanks for your comments.

Reviewer’s comments

Authors’ Reply

In Section 1.2, line 112-117 authors mention that “Through this innovative technology, managers can gain a detailed understanding of building energy consumption patterns by monitoring the energy usage of building facilities, including lighting, electricity, and HVAC systems, thereby improving, and optimizing energy use within the facility. The commercial and office sectors account for 71% of all global energy consumption, at least 18% of which is spent on lighting, accounting for 20% of global energy consumption [10].” – electricity is not at the same level with other building systems like lighting and HVAC systems, in fact, it is included as part of lighting consumption. Therefore, I suggest to replace the word “electricity” with “plug loads” to make the same level comparison among the building systems in this paragraph. It should be reflected as “including lighting, plug loads and HVAC systems, thereby improving, and optimizing energy use within the facility”. Also, in the next sentence please include a supporting reference for the potential plug load consumption as well, which is reported up to 33% [https://doi.org/10.1016/j.apenergy.2020.115391].

Thank you for your feedback and suggestions regarding our paper. We have now adjusted the term in the text and added the recommended citation as per your guidance.

Under section 1.2, the same ending sentence has been used for two paragraphs (3rd , line 115 onwards and 5th paragraph line 132 onwards) and referenced differently. Please keep only one of them.

Thank you for your reply, we've changed the similar section.

Occupancy detection, occupancy prediction technologies along with ML approaches and the connection between occupancy and DT technology should be covered more clearly. Occupancy is important for annual energy use calculations, and DT technology can be absolutely useful for occupancy prediction in real-time. Section 5.2 or related others in Table 2 should also briefly mention this. More specifically, how established wireless technologies such as Wi-Fi [https://doi.org/10.1016/j.enbuild.2018.06.040] and BLE [https://doi.org/10.1016/j.buildenv.2020.106681] as well as sensor fusion approaches [https://doi.org/10.1016/j.buildenv.2022.109689] can be used for occupancy detection/predictions along with various ML models to support DT should be discussed as part of Section 5.2 with the supporting occupancy literature.

After careful consideration of the paper and discussion, we have incorporated the last two references into our article as they are highly relevant to our topic, while the other two do not demonstrate strong relevance despite their use of machine learning.

Similarly for Section 5.2, among the deep learning technologies, reinforcement learning for the use of HVAC control is currently very popular and seems a bit rushed in the manuscript. In line 1215, one of these studies mentioned that there are more advanced approaches which combine time-series forecasting with reinforcement learning available [https://doi.org/10.1016/j.apenergy.2023.120936]. Please briefly cover the recent advancements and update it in Table 2.

 Minor Comments,

-        Line 99,106, and all other related lines, please change CO2 to “CO2”.

-        Missing space in line 1215 between the reference and the word “[156]used”.

-        Missing space in line 1160 between the reference and the word “[181]adopted”.

-        Missing space in line 1187 between the reference and the word “[161]used”.

-        The issue of missing space is also available in line 1190,1120,1104,1077,1088 and others. Please carefully check the entire manuscript and remove them accordingly.

Thank you for your valuable suggestions on our paper. Your attention to detail has undoubtedly contributed to the enhancement of our work's quality. We have checked and adjusted the text as per your recommendations. Once again, we appreciate your constructive feedback. If you have any further observations or suggestions, please do not hesitate to share them with us.

The level of English is satisfactory, my only comment is addressing the minor comments related to the editing.

Thank you for your feedback, we appreciate it. We have addressed all minor comments and make the necessary edits to improve the manuscript's clarity.