Experimental Investigation of Wind Effect on Roof Configurations with Photovoltaic Panel Systems for Sustainable Building Design

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this manuscript, the author studied the aerodynamic behavior of roof structures under wind-induced forces, focusing on buildings equipped with photovoltaic panels. They highlighted the impact of roof geometry and PV panel placement on the pressure distribution, with notable variations due to flow separation and vortex formation around the panels. The idea is good, and the work is conducted well, thus, it could be considered for publication in Sustainability, but after major revisions.

• The introduction section is very short. The authors need to provide further, latest developments in this area. The last paragraph also needs to be discussed further, comprehensively, to convince the readers about the novelty and importance of this article.
• Equations are without references, which restricts the reproducibility of this work.
• In Sections 2.2, 2.3, and 3, the authors should avoid using bullet points and instead write the discussion in a paragraph. This style shouldn’t be used for research articles; instead, only be used for reports, assignments, books, presentations, etc.
• In sections 3 and 4, the author provided very brief details about the parameters used. They should have extensively discussed these things to provide all relevant details comprehensively.  
• Figures and table captions are too short. These should be extended to provide ease for the readers.
• The added headings for sections are not appropriate regarding publication perspective; these should be revised, such as 5.2, 5.3
• The conclusion section needs further improvements regarding the manuscript's key achievements and importance.

Author Response

Response to Reviewer 1 Comments

1. Summary

We would like to thank Reviewer 1 for their constructive and detailed feedback. We have revised the manuscript thoroughly, addressing all comments and suggestions. The revised version includes improvements to the introduction, methodology, conclusions, formatting of headings and captions, and strengthened discussion on the article's contribution to sustainability. All changes have been marked in the revised manuscript using track changes.

 

3. Point-by-point Response to Comments and Suggestions for Authors

Comment 1:
The introduction section is very short. The authors need to provide further, latest developments in this area. The last paragraph also needs to be discussed further, comprehensively, to convince the readers about the novelty and importance of this article.

Response 1:
Thank you for this observation. We have substantially expanded the introduction by including recent developments in the field of wind effects on photovoltaic systems and by reinforcing the novelty of our approach. In particular, a new paragraph was added to highlight the connection with sustainable building practices and renewable energy integration. The final paragraph of the introduction was revised to clearly articulate the aims, originality, and relevance of our experimental work.
Changes can be found on page 2, paragraphs 3–5.

 

Comment 2:
Equations are without references, which restricts the reproducibility of this work.

Response 2:
We fully agree. References have now been added for all equations used in the manuscript, particularly in Sections 2.1–2.5.
These references are clearly indicated near the equations on pages 3–7.

 

Comment 3:
In Sections 2.2, 2.3, and 3, the authors should avoid using bullet points and instead write the discussion in a paragraph. This style shouldn’t be used for research articles; instead, only be used for reports, assignments, books, presentations, etc.

Response 3:
Thank you for your valuable suggestion. All bullet points in the mentioned sections have been removed and rewritten in paragraph form for improved academic tone and consistency.
Changes are located on pages 4, 5, and 7.

 

Comment 4:
In sections 3 and 4, the author provided very brief details about the parameters used. They should have extensively discussed these things to provide all relevant details comprehensively.

Response 4:
We agree that further elaboration was needed. Therefore, Sections 3 and 4 have been significantly expanded to provide detailed information about the experimental setup, model geometry, sensor placement, measurement parameters, and wind tunnel conditions.
Changes are reflected in pages 8–12.

 

Comment 5:
Figures and table captions are too short. These should be extended to provide ease for the readers.

Response 5:
Thank you for this remark. All figure and table captions have been reviewed and rewritten to provide complete, self-explanatory descriptions that improve clarity and reader understanding.
Changes are visible in the captions throughout the manuscript, e.g., Figures 7–12, Tables 2–4.

 

Comment 6:
The added headings for sections are not appropriate regarding publication perspective; these should be revised, such as 5.2, 5.3.

Response 6:
We appreciate this observation. The subheadings have been revised for clarity and better alignment with journal conventions.

 

Comment 7:
The conclusion section needs further improvements regarding the manuscript's key achievements and importance.

Response 7:
We thank the reviewer for this helpful suggestion. The conclusion section has been revised to emphasize the key findings of the study and their implications for safe, efficient, and sustainable integration of PV systems on buildings. A new closing paragraph was also added to stress the relevance of the research to sustainable development and climate-resilient infrastructure.
See page 22, Conclusion, paragraphs 2–3.

 

4. Response to Comments on the Quality of English Language

We have carefully reviewed and edited the manuscript to improve clarity, grammar, and academic style. Minor revisions have been applied throughout the text. The language has been checked using both internal review and automated tools.

 

5. Additional Clarifications

We have also revised the Title, Abstract, and Keywords as requested by the Editorial Team to better reflect the contribution of this work to sustainability. These changes highlight the connection with sustainable building design and renewable energy integration, consistent with the scope of the journal.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article focuses on the analysis of the aerodynamic behavior of roofs with photovoltaic (PV) panels installed under wind load conditions. The main research question concerns the influence of roof geometry and PV panel layout on the distribution of dynamic pressure under the influence of different air flow angles. This is an important topic for civil engineering and renewable energy, especially in the context of the growing demand for PV systems and the need to ensure their stability in various weather conditions. The work fills a research gap concerning the specific interactions of wind with pitched roofs, which are a common form of construction in residential and commercial buildings. The article provides important information on the differences in pressure distribution between gable, hipped, and multi-pitched roofs. Nevertheless, despite the valuable experimental data, the article has several significant shortcomings:

1. Both the literature review and the article lack references to other similar studies and comparisons of their results.
2. A more extensive analysis of existing wind load standards for roofs with PV panels is missing. The references are correct, but in some places there is no explanation of why the sources were used.
3. The study was conducted in a wind tunnel using 1:100 scale models, which is a standard technique in this type of analysis, but there is no information on how the results were scaled to real conditions.
4. Figures 7 and 8 are visually identical, therefore I believe that Figure 8 does not add anything significant and there is no need to present both. The same applies to Figures 9, 10, and 11, 12.
5. The conclusions of the article are generally consistent with the data presented, but do not include sufficient discussion of the practical implications of the results. The limitations of the study, such as the influence of turbulence, which cannot be fully reproduced in a wind tunnel, are also not addressed. Suggestions for future research, such as experiments in real atmospheric conditions, would be welcome.

Author Response

Response to Reviewer 2 Comments

We thank Reviewer 2 for the time and effort invested in reviewing our manuscript and for the insightful comments that helped us improve the quality and clarity of the paper. We have addressed each point carefully and incorporated the suggested revisions. Below we provide a point-by-point response.

 

Comment 1:

Both the literature review and the article lack references to other similar studies and comparisons of their results.

Response 1:
Thank you for this observation. We have expanded the literature review in the Introduction and in Section 2.4 to include relevant studies that have addressed similar aerodynamic phenomena in the context of rooftop PV systems. Comparative analysis with prior research by Aly and Rone, Banks et al., Kopp and Morrison, and Shen et al. has been added. In addition, direct comparisons with literature findings were included at the end of each result subsection (Sections 5.1–5.3), contextualizing our findings with previous experimental data.
(See: Introduction, pages 2–3; Sections 5.1–5.3, pages 17–21.)

 

Comment 2:

A more extensive analysis of existing wind load standards for roofs with PV panels is missing. The references are correct, but in some places there is no explanation of why the sources were used.

Response 2:
We agree and have now elaborated on this point in Section 2.5 – Implications for structural design. A detailed discussion was added explaining the limitations of Eurocode 1 and ASCE 7-22 in relation to complex or pitched roofs with elevated PV systems. The absence of detailed guidelines in these standards has been connected to the need for studies like ours. The following reference was added to support this discussion:
ASCE. Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE/SEI 7-22); American Society of Civil Engineers: Reston, VA, USA, 2022.
(See: Section 2.5, page 7; new reference [23].)

 

Comment 3:

There is no information on how the results were scaled to real conditions.

Response 3:
Thank you for pointing out this important aspect. We have included a new subsection titled 3.3. Scaling and dimensional analysis that explains how pressure coefficients, being dimensionless, enable extrapolation to full-scale behavior. The limitations related to Reynolds number mismatch and turbulence replication in wind tunnels are acknowledged, and the applicability of the results to real structures is discussed.
(See: Section 3.3, pages 13–14.)

 

Comment 4:

Figures 7 and 8 are visually identical, therefore I believe that Figure 8 does not add anything significant and there is no need to present both. The same applies to Figures 9, 10, and 11, 12.

Response 4:
We appreciate the reviewer’s observation. While Figures 7–8, 9–10, and 11–12 share similar visual patterns due to the direct mathematical relationship between the pressure coefficient and the calculated dynamic pressure, we respectfully suggest keeping both figures for each model. This is because they communicate different physical quantities that are relevant to distinct engineering applications: the pressure coefficient is useful for comparative aerodynamic analysis across configurations and scales; the dynamic pressure provides absolute values necessary for structural design and load calculations.

 

Comment 5:

The conclusions of the article are generally consistent with the data presented, but do not include sufficient discussion of the practical implications of the results. The limitations of the study, such as the influence of turbulence, which cannot be fully reproduced in a wind tunnel, are also not addressed. Suggestions for future research, such as experiments in real atmospheric conditions, would be welcome.

Response 5:
We agree with this valuable suggestion. The Conclusion section has been expanded to discuss specific practical implications of our findings, such as recommendations for PV panel mounting systems on pitched and multi-surface roofs. Furthermore, we have added a paragraph acknowledging the limitations of the wind tunnel method—particularly the limited representation of real atmospheric turbulence—and the need for future validation through full-scale field studies and CFD simulations.
(See: Conclusion, page 22.)

 

Additional Clarifications

We have also revised the Title, Abstract, and Keywords as requested by the Editorial Team to better reflect the contribution of this work to sustainability. These changes highlight the connection with sustainable building design and renewable energy integration, consistent with the scope of the journal.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

 

1          Structure of the paper. Please improve the structure of this paper with the following suggestions:

Introduction - State the objectives of the work and provide an adequate background, avoiding a detailed literature survey or a summary of the results.

• Material and methods - Provide sufficient details to allow the work to be reproduced by an independent researcher. Methods already published should be summarized and indicated by a reference. If quoting directly from a previously published method, use quotation marks and cite the source. Any modifications to existing methods should also be described.
• Theory/calculation - A theory section should extend, not repeat, the background of the article already dealt with in the introduction and lay the foundation for further work. In contrast, a Calculation section represents a practical development from a theoretical basis.
• Results - Results should be clear and concise.
• Discussion - This should explore the significance of the results of the work, not repeat them. A combined Results and Discussion section is often appropriate. Avoid extensive citations and discussion of published literature.
• Conclusions - The study's main conclusions may be presented in a short Conclusions section, which may stand alone or form a subsection of a Discussion or Results and Discussion section.
• References – the most essential papers about your topic from the last five-ten years.

2          In this paper, the Authors should underline the novelty in the introduction. The state of the art is really poor, thus, please improve this aspect in the paper about the structures with vulnerability to the wind (e.g. lightweight structures)

3          Please use the correct units – line 53 (please review all text)

4          What is the next step of your research?

Comments on the Quality of English Language

Please check all the text by Native speakers

Author Response

Response to Reviewer 3 Comments

We would like to thank Reviewer 3 for the valuable feedback and constructive suggestions that helped improve the scientific clarity, structure, and relevance of our manuscript. We have addressed each comment carefully and revised the manuscript accordingly. Below is a point-by-point response.

 

Comment 1:

Structure of the paper. Please improve the structure of this paper with the following suggestions… [Introduction, Methods, Theory, Results, Discussion, Conclusions].

Response 1:
Thank you for this detailed structural guidance. We have reorganized and refined the manuscript structure to align with the recommended format. The Introduction now focuses on contextual background and study objectives, without summarizing results. A dedicated section for theoretical considerations has been maintained (Section 2), clearly separated from the experimental methodology (Section 3). A combined “Results and Discussion” section (Section 4) has been developed to provide integrated interpretation of the data. The Conclusions (Section 5) now summarize the key findings and include a note on future research directions. References were updated and focused on recent literature from the last 5–10 years.

(See: Sections 1–5, pages 1–22)

 

Comment 2:

In this paper, the Authors should underline the novelty in the introduction. The state of the art is really poor, thus, please improve this aspect in the paper about the structures with vulnerability to the wind (e.g., lightweight structures).

Response 2:
We agree with this valuable observation. The Introduction has been revised to emphasize the novelty of our study — specifically the experimental comparison of three pitched roof geometries with PV panels under identical wind tunnel conditions, a topic not extensively addressed in current literature. The state of the art has been expanded with references to recent studies addressing lightweight structures and wind vulnerability, including gable, hip, and irregular roof shapes with PV systems. The vulnerability of lightweight roofs has also been explicitly discussed in Section 2.3 and the Introduction.

(See: Introduction, pages 1–3; Section 2.3, page 5)

 

Comment 3:

Please use the correct units – line 53 (please review all text).

Response 3:
Thank you for pointing this out. We have thoroughly reviewed the manuscript and corrected all units to comply with SI formatting.

(See: all sections, throughout the manuscript)

 

Comment 4:

What is the next step of your research?

Response 4:
We appreciate this question. A paragraph has been added to the Conclusions section outlining the future direction of our research. This includes computational fluid dynamics (CFD) simulations to validate the wind tunnel results under more complex flow conditions, as well as planned full-scale experimental studies in real environments to account for atmospheric turbulence and real-world variability.

(See: Section 5 – Conclusions, page 22)

 

Comment 5 – Language:

Please check all the text by native speakers.

Response 5:
The manuscript has been carefully revised for clarity and academic English. Grammar, syntax, and terminology were reviewed throughout the document to improve readability and ensure consistency of technical expressions. Particular attention was paid to complex phrasing in the Introduction, Theoretical Background, and Results sections.

(See: full manuscript)

Additional Clarifications

We have also revised the Title, Abstract, and Keywords as requested by the Editorial Team to better reflect the contribution of this work to sustainability. These changes highlight the connection with sustainable building design and renewable energy integration, consistent with the scope of the journal.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version is fine and could be considered for publication. 

Author Response

We would like to thank Reviewer for his constructive and detailed feedback

Reviewer 2 Report

Comments and Suggestions for Authors

All my comments and questions have been clarified and corrected in the text of the article, so I believe it is ready for publication in present form.

Author Response

We would like to thank Reviewer for his constructive and detailed feedback

Reviewer 3 Report

Comments and Suggestions for Authors

Please add more papers to the references. In my opinion, the number of papers is too small.

Author Response

We would like to thank Reviewer for his constructive and detailed feedback

We improved our reference list according to recommendations. All changes have been marked in the revised manuscript.