Experimental Study of Phase Change Microcapsule Suspensions Applied in BIPV Construction
, Kuan Wang 3, Feng Han 3, Xiaoge Li 3 and Yuqiang Zhao 2Round 1
Reviewer 1 Report
This paper conducted an experimental study on PV-PCM system in the May of Nanjing. Results show the PCM can effectively reduce the PV temperature. Then a simple simulation was conducted to prove the PCM can also benefit the building energy saving. Overall, the paper is poorly organized and written. Major problems include:
- Lack of novelty. The concept of integrating PCMs with PV panels is not new. It is obvious that PCMs can flatten the cell temperature curve during daytime and improve the PV performance. Is it a new material or fabrication method that no one ever reported? It is not clear in this manuscript. The simulation method is oversimple, which simply estimates constant PCEs for both cases.
- Lack of material characterization. The authors mentioned several important PCM parameters, such as latent heat, specific heat, phase change temperature range, etc. However, none of them was mentioned in Table 1.
- Lack of simulation details. Many factors can affect the overall building energy, such as window and wall properties, HVAC systems, equipment loads, etc. The author should specify the modeling details so that readers know the comparison is reasonable. I assume the authors used the weather data of Nanjing for simulations. It would be better to compare the overall performance under different climates.
- Lack of a comprehensive literature review.
- Language needs to be improved.
Based on the reasons above, I have to reject this paper. In the future, a meaningful comparison could be between the cost of integrating PCM and the extra PV generation due to lower temperature + building energy saving. Feasibility of PV-integrated PCM should also be discussed, e.g., extra weight, lifetime, waterproof, fireproof, etc. Some small issues deserve the authors' attention in future submission:
- Figure 1 contains non-English characters.
- Pinyin like T_{beibanwendu} should be avoided.
- Space should be added between numbers and units, e.g., 114 min.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript covers an interesting R&D topic and fits the scope of the Journal. Nonetheless, the paper requires extra efforts to improve its quality and presentation. A set of comments are expounded hereafter.
- The manuscript is, in general, well organized. However, there are some mistakes or improvements to introduce regarding the format of the document, as commented below.
The parentheses are not required in the affiliation.
The acronym BIPV should be decomposed the first time that it appears in the Abstract.
The template of the journal must be strictly followed.
Figure captions lack the terminal period (punctuation). The same issue occurs for titles of tables.
The information about funding of the work should be placed before the References in the section named as Funding.
- About the content of the manuscript, as aforementioned, it covers an interesting topic. The comments after a careful revision are the following:
A desirable keyword is “Renewable energy”, if the authors agree with the suggestion.
At least a brief sentence should be included in the sections before the subsections that compose them. This facilitates the reading and is applicable to sections 2 and 3.
The cited references seem old, the most recent corresponds to 2017. In this regard, it is suggested adding recently published articles which serve to highlight the relevance of temperature in photovoltaic energy generation as well as to clearly state that the topic of the manuscript is a current research field. Some recent papers that the authors could consider are now given:
- Photovoltaic Thermal Collectors Integrated with Phase Change Materials: A Comprehensive Analysis. Electronics 2022, 11, 337. https://doi.org/10.3390/electronics11030337
- Assessment of PV Module Temperature Models for Building-Integrated Photovoltaics (BIPV). Sustainability 2022, 14, 1500. https://doi.org/10.3390/su14031500
- Photovoltaic Panels Temperature Regulation Using Evaporative Cooling Principle: Detailed Theoretical and Real Operating Conditions Experimental Approaches. Energies 2021, 14, 145. https://doi.org/10.3390/en14010145
- Monitoring System for Tracking a PV Generator in an Experimental Smart Microgrid: An Open-Source Solution. Sustainability 2021, 13, 8182. https://doi.org/10.3390/su13158182
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A common practice in scientific papers consists on indicating the structure of the rest of the manuscript at the end of the Introduction, so the reader knows its layout.
In the third section, what type of irradiation sensor is used?
The fact of providing experimental results is a positive feature.
What is the version of the DesignBuilder software? This information could be useful for the interested reader.
The Conclusions should include some future guideline derived from the reported research.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
This article provides quite interesting presentation and analysis of the phase change microcapsule suspensions.
There are few very good points which are pointed out by the author and bring following related questions. I could appreciate very much the fact, that the author works with quite wide range of the references, so the article is supported by sufficient literature background.
The only weak part of the article id the Conclusion, which is quite short and basically too general, without any information about current movement of the regulator status regarding the relations to the fintech credit providers.
The scientific soundness is quite high, but without any doubt it brings lot of interest from the side of the non-expert readers.
There are very many authors opinions and suggestions, which brings higher scientific standards for the article quality.
Overall merit is very good, and this article is ready to be published even without any prolongation of the conclusion.
Author Response
More perfect conclusions are added, three conclusions are subdivided, and the development of phase change system in experimental research is explained.
Reviewer 4 Report
Please see the attached file.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have substantially improved the manuscript. However, the language still needs further improvement to avoid misunderstanding. I suggest asking a native English speaker to revise the paper. The authors seem overlooking my previous comments on a further comparison:
"…In the future, a meaningful comparison could be between the cost of integrating PCM and the extra PV generation due to lower temperature + building energy saving. Feasibility of PV-integrated PCM should also be discussed, e.g., extra weight, lifetime, waterproof, fireproof, etc. "
I suggest the authors to add some discussions to the last section.
The authors claimed "the suspension can also make photovoltaic modules photoelectric conversion efficiency increased by about 10%" in the abstract. However, I read through the manuscript and cannot find where the 10% result come from. In the simulation, the authors simply assume a PCE of 15% for BIPV and 16% for BIPV-MPCMS. So the conclusion of 6.7% improvement of PCE is meaningless, which equals (16-15)/15*100%. Since the PCE highly depends on the module temperature in this study, the PCE improvements are also changing with time of day and day of the year. A meaningful comparison can be found on annual energy yield instead of PCE.
Some small issues:
1. PCE and temperature coefficients of the PV module is not mentioned in Table 2
2. The authors use "photovoltaic conversion efficiency"(Line 224) and "photoelectric conversion efficiency" (Line 226). I cannot tell the difference. Usually, we use "power conversion efficiency" (PCE) in PV communities.
3. Units kwh and mwh in figure 10 and 11 should be kWh and MWh, respectively.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The new version has properly addressed the provided suggestions.
Author Response
Thank you for your comments and suggestions.
Reviewer 4 Report
The authors have revised the manuscript by incorporating issues raised in my review. I am happy with the revised manuscript.
Author Response
Thank you for your comments and suggestions.
Round 3
Reviewer 1 Report
The authors addressed my concerns in the revised manuscript, however, left several small issues to be fixed.
Table 2
A silicon-based PV module usually has a negative temperature coefficient. Probably -0.4 is correct.
Regarding the added two rows, units should stay in the first column, consistent with the row above.
Figure 10-11
Unites are wrong. Capital W stands for watt.
Discussion
"…, changing structural stability, pay attention to waterproof and fireproof. these increase the cost of integrating PCM more or less." The authors should rephrase the sentence.
"…the development of BIPV-MPCMS system is an inevitable trend…". The word "inevitable" is too strong. Unsupported conclusions should not appear in discussions.
Author Response
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Author Response File: Author Response.pdf
