Estimation of the Optimum Tilt Angle of Solar PV Panels to Maximize Incident Solar Radiation in Libya^†

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. where is the work's novelty, and is the used method known?

2. why did the authors not use an optimization algorithm for determining the tilt angle?

3. The review part needs to be enlarged.

4. solar radiation used in the experiment as mentioned in the abstract" the measured data", what is the period for measurement?

5. Figure 4 discusses a comparison between this work and reference [11], the authors should explain the difference in the results in terms of solar radiation to clarify the effect of tilt angle.

6. Figure 3 needs to be cleared.

 

 

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This  article titled “Estimation of the optimum tilt angle of solar PV panels to maximize incident solar radiation in Libya”

The study aims to optimize the tilt angle of solar photovoltaic (PV) systems, which is a crucial parameter for their design as it determines the amount of radiation incident on PV panels.

·        Methodology: The authors seem to have conducted empirical studies and used statistical analysis to arrive at their conclusions

·        Findings: The results indicate that both third-order polynomial and Fourier model presented better efficiency in estimating the optimum tilt angle where R² = 0.9934.

·        The paper well written

·        My comments, suggestions, and views on this article are as follows:

- Nomenclature section should be added.

- I think the abstract could be better than now. A good quality abstract should include the purpose, methods, findings, conclusions, and recommendations of the research without details.

- Introduction

This section should provide a more relevant literature, an introduction to the methods used in this study.

- All equations and numbers should be revised

- I think it is better if the title will be improved to be more technically sound.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This paper aims to estimate the optimum tilt angle of solar PV panels to exploit the maximum daily solar radiation on the inclined surface. Six empirical models were established to estimate the optimum tilt angle of PV panels. Their empirical coefficients were determined using non-linear regression technique. Overall, the paper is written well, however, there are a few concerns that need to be fixed while preparing the revisions.

1)     It is recommended to expand the introduction section by adding more recent studies on the "optimum tilt angle" for the same region.

2)     Organization of the manuscript at the end of introduction section is recommended.

3)     It is recommended to expand the description of the system given in Figure 2.

4)     What was the source(s) of the metrological data used in the study?

5)     The main equation to calculate the actual solar radiation gain on a tilted solar collector is missing.

6)     It is recommended to add brief explanation of the derivation of the of the equation and/or add references to the presented equations.

7)     It is also recommended to briefly explain the variables used in the equations at the appropriate location within the text.

8)     It is recommended to add a figure showing the variation of optimal monthly angle of tilt as a function of latitude for Libya. This would signify a trend for the optimal angle of tilt for varying latitudes in different climatic zones of the Libya.

9)     What was the percentage increase in seasonal solar radiation gains due to optimal tilt compared with annual fixed tilt for different locations? It is recommended to present (in a tabular form) the percentage increase in the amount of solar radiation falling on the collector surface, obtained for seasonal and monthly optimum tilt compared to annual fixed tilt.  

10) Conclusions should be curtailed summarizing only key points. Further study limitations should be added.

11) The linguistic quality of the paper also warrant improvement.

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

In my opinion, the proposed manuscript is not ready for publication. However, it may be potentially interesting for readers when you improve the quality of the paper. Below you can find some suggestions:

1) The English language requires significant improvements.

2) The paper structure should be reorganized. Please use the IMRaD structure (i. Introduction, ii. Materials and Methods, iii. Results and Discussion, iv. Conclusions).

3) At the end of the "Introduction" section, please clearly explain the novelty of your works (which gap in the current knowledge was solved by the discussed studies).

4) Please check the literature review. Many sources used in the paper are older than a few years.

5) The "Materials and Methods" section should be rewritten to show step-by-step the most important information regarding your research, including a more detailed description of the research procedure, experimental rig, etc.

6) The "Results and Discussion" section should include the presentation and discussion of the research. All theoretical information and equations should be presented in the "Materials and Methods" section.

7) Furthermore, the "Results and Discussion" section should be rewritten to clearly show and discuss step-by-step the achieved results. Actually, the organization of this section is a bit chaotic.

7) As the measurements of solar irradiations are quite obvious, I suggest performing further investigations, for example:

- the simulation of the performance of the solar installation,

- the assessment of potential improvements in energy production resulting from the introduction of the new knowledge obtained during your investigations.

Comments on the Quality of English Language

Please carefully check the English language. There are many parts, when English requires improvements.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript has undergone significant improvement, and I recommend it for publication.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

thank you for the improvements made to the manuscript. However, it requires some further modifications. Please include in the paper the following suggestions:

1. Nomenclature should be moved (it should be placed at the end of the paper or at the beginning of the paper). 

2. Please include information regarding the measurement accuracy of the meteorological station and analysis of measurement errors.

3. Please check the "Results and Discussion" section and move some information to the "Materials and Methods" section. For example, lines 241-256 include a description of the experiments, not a discussion of the results.

4. Consider moving some tables and/or figures to the appendix to clarify the paper structure (you can hold the core discussion in the paragraphs, but place detailed numbers in the appendix). 

Author Response

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Author Response File: Author Response.pdf

Round 3

Reviewer 4 Report

Comments and Suggestions for Authors

Thank you for improving your paper according to suggestions.