Analysis of Nanofluids Behavior in Concentrated Solar Power Collectors with Organic Rankine Cycle

Round 1

Reviewer 1 Report

Review of the paper

Title: Analysis of Nanofluids Behavior in Concentrated Solar Power Collectors with Organic Rankine Cycle

By: S. Sami

Submitted to: applied system innovation

Manuscript ID: asi-538496

This paper presents a study on the effect of nanofluids characteristics and performance in concentrated solar power collectors with organic Rankine cycle system. The scope of the journal fully covers this research subject. On its actual form, the paper looks more like a conference paper or a draft summary report, rather than a scientific paper. The main goal of the article and the novelty of the work should be clearly defined in the introduction. Introduction section should be revised since it does not contain the last references in the field. The description of the methodology and discussion of the results lack attention to details and were not clearly described. There is no ground-breaking outcome from a stated research objective. The whole paper needs to be re-written to include a comprehensive discussion on the used methodology, compare it with other methods, explanation, and discussion of results. In addition, the paper requires significant improvement in the manner in which it is written. This paper does not meet the expectations of an ASI journal paper and cannot be recommended for publication in its current form.

Below I have listed the following main issues:

1. The introduction can be more focused in my opinion, authors should improve it. It does not provide sufficient background. The author should also include the specific objectives in the introduction.

2. In addition, the author should make clear what the real benefit to science is. Please clarify the novelty of the submitted manuscript and refer to previous frameworks and guidelines. Explain the value of this research.

3. In Section 2, line 121, provide a summary table with the main properties of the quaternary mixture. Provide also the thermodynamic graphs such as the T-s diagram.

4. In Section 2, list the main assumptions pertaining to the different models as per Eqs. 1-23. Provide the physical, thermodynamic and chemical properties and input parameters.

5. Provide details on the numerical procedures used to solve Eqs. 1-23 and parameter settings in Matlab.

6. Section 3 needs more details on the experimental measurement, input data and specifications of the systems.

7. In Section 3, the author should propose tentative interpretation, potential physical reasons behind the described behaviour of his results.

8. In Section 3.1 there is a large discrepancy between measured and model data. The discrepancy between the measured and predicted data, is attributed also to real data uncertainty: what is the uncertainty on the measured data.

9. The conclusion is abbreviated, the limitations of this study, suggested improvements and future direction of this work should be highlighted; the main findings resulting from the study should be clearly identified.

10. Improve the Abstract.

11. There are many spelling and grammar mistakes. Run the spelling and grammar tool.

12. Check the references. The format is not adequate.

13. Improve the quality/presentation of the figures.

Author Response

The paper has been revised according to the reviewer #1 comments and suggestions;

The following is our response to the comments made by the reviewer;

Introduction has been revised.

Benefits to the science has been added

Thermodynamic properties P-H diagram has been added

Main assumptions and chemical properties have been added

Details of the numerical solution are provided in Figure .2

No experimental measurements were conducted in this research work, however, our model was compared to experimental data reported by references [31] and [35]. Details of these experimental data are provided in references [31] and [35].

Interpretation of the numerical and model validation were in the paper

Discrepancy between experimental data reported in other references and model results were explained and the discrepancies are within acceptable levels and less that 10%.

Conclusion was improved

Abstract was also improved. 

  11, 12 and 13 were addressed

Reviewer 2 Report

This is an interesting study coupling behaviour of nanofluids in CSP and linked ORC system.

Introduction is appropriate but list of references is excessive. 

Perhaps a list of symbols would be more appropriate then giving definition for each parameter in the mathematical model section. 

Figure 2 is impossible to read. 

Results presented in figures 3-10 overly simplistic and reflects the irradiance pattern. Authors could present one set of figures and give the rest in a more comprehensive (table, cummulative graph) format. 

Overall presentation of graphs (titles, unit, subscripts, legends) can be improved.

Figures 18-28 show difference is estimated output as a function of nanofluid concentration; surely there is a better way of presenting the data and capturing the behaviour numerically rather than having this many graphs!

Finally (and this is my biggest criticism), model validation section shows poor correlation of data with the model, and hardly any explanation has been given for this.

Please consider the points above and make suitable changes and improvements.

Author Response

Dear reviewer #2

Greatly appreciate your comments and please note our response;

Introduction is revised according to your comments and other reviewers

The paper includes symbols definitions in the list of symbols and in-text sections

Figure .2 has been improved

Results are presented in form of graphs to clearly demonstrate the impact of the different nanofluids and solar radiations on the behavior of the CSP, ORC and hybrid system, Tables forms do not present a clearer picture of the cummulative behavior of the CSP hybrid system and the dependent parameters

We improved the presentations of some of the graphs as recommended 

We presented impact of the nanofluids on the performance of the CSP system as a function of the % concentrations of nanofluids and solar radiations since those are the most important and critical operation parameters, a designer should be concerned with. Other references also presented the impact of nanofluids on system behavior in the same manner as presented by us.

The model validation was the difficult part of this paper due to the limited number of experimental data available in the literature on CSP systems. The two references found provided limited experimental data with little details. Therefore, we had to consult additional references mentioned in the two references to gain more in-depth and in particualar for the HTC. However, the discrepancies are within acceptable levels and under 10% taking into consideration the limited details provided about the experimental data by in particular the reference [35].   

Round 2

Reviewer 1 Report

Authors addressed somewhat the comments in the revised version of the paper.

There are still some spelling and grammar mistakes and format of the references and all the paper in general need to be corrected.

Reviewer 2 Report

I am satisfied that you implemented my suggestions. I still have reservations regarding the quality of some figures, but I will leave this to the editorial team. I don't need to see the amended version as these are formatting amendments.