Internal Heat Exchanger Influence in Operational Cost and Environmental Impact of an Experimental Installation Using Low GWP Refrigerant for HVAC Conditions

Round 1

Reviewer 1 Report

1. P5, in addition to providing the capacity of the plate heat exchanger, please provide the geometric parameters including plate number, length, width, etc.
2. P9, Eqs. 4-14 should be explained. All the symbols should be specified.
3. Table 6, what is the nominal cooling capacity of the three systems?
4. Figure 4, the legend is not straightforward. Please improve. The experimental data should be extended.
5. Figure 4, What are the relevant operating pressures? What are the states at the outlet of the condenser and evaporator? Please quantify.
6. Table 7, the compression work should be presented.
7. Figure 5, why the compressor has the largest losses?
8. The improvement of cycle performance with IHX should be explained relevant to fluid properties.

Author Response

Response to reviewer 1.

 

• P5, in addition to providing the capacity of the plate heat exchanger, please provide the geometric parameters including plate number, length, width, etc.

Thank you for your comment. We have added Table 3 with the information as you request.

• P9, Eqs. 4-14 should be explained. All the symbols should be specified.

In attention to your request, we have explained eqs. 4-14 and we have specified all symbols in the paper.

• Table 6, what is the nominal cooling capacity of the three systems?

Thanks for your observations. The information that you request has been added in bottom of Table 7.

• Figure 4, the legend is not straightforward. Please improve. The experimental data should be extended.

For Figure 4 (now Figure 5) legend was modified. Also, the experimental data was extended.

• Figure 4, What are the relevant operating pressures? What are the states at the outlet of the condenser and evaporator?

Information about operating pressures and states at the outlet of the condenser and evaporator was included in a new Table (Table 8) of this paper.

• Table 7, the compression work should be presented.

We have added a new column in Table 9 (before Table 7) with the information as you request.

• Figure 5, why the compressor has the largest losses?

The compressor is the component that presents the highest exergy destruction ratio for each cycle configuration, due to the high-pressure ratio values that lead to a higher compression power requirement for all the conditions evaluated. This explanation was included in Pag. 15 lines 541-544 in the paper.

• The improvement of cycle performance with IHX should be explained relevant to fluid properties.

The explanation of the improvement of cycle performance with IHX was included in the paper in page 14, lines 510-513.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Review comments

Article: sustainability-1668540

Title: Internal Heat Exchanger Influence in Operational Cost and Environmental Impact of an Experimental Installation Using Low GWP Refrigerant for HVAC Conditions.

The main idea of the work is to evaluate the HVAC performance using R1234ze(E) as a Refrigerant fluid in an internal heat exchanger to improve the HVAC systems performance. The work is done by the experimental method.

 

1. GWP in the title should be full words.
2. The title is too long. Should be a maximum of 15 words
3. Abstract line 10 to line 13 is very poor. Revise to address the problem statement.
4. Too many abbreviations in the abstract are not advised. Re-consider.
5. The units used in table 1 are not correct. Use kJ/kgK instead of kJ/kg-K. However, the characterization is very good effort.
6. In section 2.1, add qualitative values to support the claims of the environmental effect analysis.
7. I am confused. Explain if you have an experimental setup or simulation? Have you gotten the results from experimental measurements or simulation prediction?
8. If you have an experimental setup, add a photo and label all the items on the photo.
9. Table 2. You may also add the flow rates and power measuring instruments. In the table, you showed the characteristics of the instruments. What are the uncertainties of the parameters?
10. The section on the integral analysis is very useful for other researchers. Good for you.
11. Figure 4 is not correct. When you have three data points, they are like cases. So, we cannot produce a graphical correlation between 3 data points. Results like this can be presented as a table or histogram, similar to figure 5.
12. Write sub-Heading in full. No abbreviation in the headings.
13. Revise the conclusion and reduce. Don’t repeat statements from results. Highlight only the findings that are different from previous studies.
14. Revise the list of nomenclature. You have included many abbreviations in the symbols. Take them, like ALR, RFD, SLCCP…, to the abbreviation.

There is room for English language improvement. Revise and utilize professional proofreading.

The article is wealth to be considered for publication if the review comments are considered.

Author Response

Response to reviewer 2:

 

1. GWP in the title should be full words.

We have removed GWP acronym of title of paper.

2. The title is too long. Should be a maximum of 15 words.

We have reduced the long of title, the maximum words are now of 15.

3. Abstract line 10 to line 13 is very poor. Revise to address the problem statement.

Thank you for your comments. We have reviewed the abstract and we modified line 9-12 content.

4. Too many abbreviations in the abstract are not advised. Re-consider. Respect to your comment, we think the abbreviations are necessary because are words used in all paper.
5. The units used in table 1 are not correct. Use kJ/kgK instead of kJ/kg-K. However, the characterization is very good effort. Thank you for your comments. We have made the correction according to your proposed.
6. In section 2.1, add qualitative values to support the claims of the environmental effect analysis.

According to your suugestions, in page 4, lines 196-200 we have added qualitative values to support the claims of the environmental effect analysis.

7. I am confused. Explain if you have an experimental setup or simulation? Have you gotten the results from experimental measurements or simulation prediction? Sorry for confused you. We have added photos, tables and text in section 3 where is easy to observe that the paper is based in experimental results making use of theoretical equations of Thermodynamics, environmental aspects, and theory exergy cost.
8. If you have an experimental setup, add a photo and label all the items on the photo. We appreciate your comments. In this sense, we have included Figure 1 which shows photos of experimental installation. Also, in this Figure are indicated labels and items for each circuit.
9. Table 2. You may also add the flow rates and power measuring instruments. In the table, you showed the characteristics of the instruments. What are the uncertainties of the parameters? Thank you for your observations. We have added in Table 2 both flow rate and power measuring instruments. Also, we have included the sensitivity of each equipment which are offers by each supplier.
10. The section on the integral analysis is very useful for other researchers. Good for you. Thank you very much for your comments.
11. Figure 4 is not correct. When you have three data points, they are like cases. So, we cannot produce a graphical correlation between 3 data points. Results like this can be presented as a table or histogram, similar to figure 5. Thank you for your comments. Respect to your suggestion, we have modified Figure 4 (now Figure 5) according to your comments.
12. Write sub-Heading in full. No abbreviation in the headings. Thank you for this observation. We have written sub-heading in full.
13. Revise the conclusion and reduce. Don’t repeat statements from results. Highlight only the findings that are different from previous studies. Thank you for your observations. We have corrected and reduced the conclusions section.
14. Revise the list of nomenclature. You have included many abbreviations in the symbols. Take them, like ALR, RFD, SLCCP…, to the abbreviation. We appreciate your comments. We have included the significance of all abbreviations in nomenclature section.

 

Finally, we have reviewed the paper fully and we have made grammar corrections. Thank you very much for your valuable comments which will serve to improve the quality of paper.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Accept