Using Green Energy Sources in Trigeneration Systems to Reduce Environmental Pollutants: Thermodynamic and Environmental Evaluation
, Shayan Sharafi Laleh 1, Saeed Soltani 1,*, Mortaza Yari 1,* and Marc A. Rosen 2
Round 1
Reviewer 1 Report
Dear Sir, I have very thoroughly read and considered the manuscript ID as Sustainability2517954, entitle: "Using green energy sources in trigeneration to reduce environmental pollutants: Thermodynamic and Environmental Evaluation. This manuscript represents a novel dual-source trigeneration cycle based on a biogasfueled gas turbine and geothermal cycles and clean water production. For my opinion, I feel very satisfy for the results obtained together with objectives and a novel of work were achieved. Therefore, I have concluded that this article is accepted to public in Sustainability Journal.
Here they are, some more questions and comments;
1. For the keyword of HDH, what is HDH stand for? and also in the abstract for the
technic term of EES software.
2. For Fig.1 Schematic of trigeneration system, it should be better if the authors could
improve whole Figure especially the labels should expand to make it clear. In
addition a cited reference for the fig. should be added.
3. The authors should discuss the capacity or the efficiency among 4 cycles of
trigeneration system.
4. Figs.2-Figs.9, the authors should make more comparisons the results obtained and
Previous studies.
5. List of the main findings, indicated in the section of conclusion, should move to the
section of results and the authors should make a discussion for the results obtained
and make a comparison among previous studied.
6. Please rewritten the section of conclusion to make it in one passage and also
conclude that how the trigeneration system worked.
7. Others; equations should be done in the same pattern as well as all nomenclature
should be added.
Author Response
Dear reviewer #1,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
Dear Sir, I have very thoroughly read and considered the manuscript ID as Sustainability2517954, entitle: "Using green energy sources in trigeneration to reduce environmental pollutants: Thermodynamic and Environmental Evaluation. This manuscript represents a novel dual-source trigeneration cycle based on a biogasfueled gas turbine and geothermal cycles and clean water production. For my opinion, I feel very satisfy for the results obtained together with objectives and a novel of work were achieved. Therefore, I have concluded that this article is accepted to public in Sustainability Journal.
Here they are, some more questions and comments;
- Comment: For the keyword of HDH, what is HDH stand for? and also in the abstract for the
technic term of EES software.
Response: The abbreviation of these words was added to the nomenclature section. However, HDH stands for humidification and dehumidfication, and EES stands for Engineering equation solver.
- Comment: For Fig.1 Schematic of trigeneration system, it should be better if the authors could improve whole Figure especially the labels should expand to make it clear. In addition a cited reference for the fig. should be added.
Response: The schematic of the proposed system was modified and improved in terms of quality. (Please see line 116 and line 118).
- Comment: The authors should discuss the capacity or the efficiency among 4 cycles of
trigeneration system.
Response: Table 4 shows the amount of energy efficiency, exergy efficiency and net output power of each system. (Please see line 262-269).
- Comment: 2-Figs.9, the authors should make more comparisons the results obtained and
Previous studies.
Response: In section 5, the comparative table of the present work with previous studies is shown. The results of this table show that the current proposed system is better.(please see conclusion section and table5).
- Comment: List of the main findings, indicated in the section of conclusion, should move to the
section of results and the authors should make a discussion for the results obtained
and make a comparison among previous studied.
Response: The list of main findings was added to the results and discussion section under the overall performance results title.
- Comment: Please rewritten the section of conclusion to make it in one passage and also
conclude that how the trigeneration system worked.
Response: The conclusion section was modified.
- Comment: Others; equations should be done in the same pattern as well as all nomenclature
should be added.
Response: All abbreviations used in equations are available in the nomenclature section.
Dear reviewer #1,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
Dear Sir, I have very thoroughly read and considered the manuscript ID as Sustainability2517954, entitle: "Using green energy sources in trigeneration to reduce environmental pollutants: Thermodynamic and Environmental Evaluation. This manuscript represents a novel dual-source trigeneration cycle based on a biogasfueled gas turbine and geothermal cycles and clean water production. For my opinion, I feel very satisfy for the results obtained together with objectives and a novel of work were achieved. Therefore, I have concluded that this article is accepted to public in Sustainability Journal.
Here they are, some more questions and comments;
- Comment: For the keyword of HDH, what is HDH stand for? and also in the abstract for the
technic term of EES software.
Response: The abbreviation of these words was added to the nomenclature section. However, HDH stands for humidification and dehumidfication, and EES stands for Engineering equation solver.
- Comment: For Fig.1 Schematic of trigeneration system, it should be better if the authors could improve whole Figure especially the labels should expand to make it clear. In addition a cited reference for the fig. should be added.
Response: The schematic of the proposed system was modified and improved in terms of quality. (Please see line 116 and line 118).
- Comment: The authors should discuss the capacity or the efficiency among 4 cycles of
trigeneration system.
Response: Table 4 shows the amount of energy efficiency, exergy efficiency and net output power of each system. (Please see line 262-269).
- Comment: 2-Figs.9, the authors should make more comparisons the results obtained and
Previous studies.
Response: In section 5, the comparative table of the present work with previous studies is shown. The results of this table show that the current proposed system is better.(please see conclusion section and table5).
- Comment: List of the main findings, indicated in the section of conclusion, should move to the
section of results and the authors should make a discussion for the results obtained
and make a comparison among previous studied.
Response: The list of main findings was added to the results and discussion section under the overall performance results title.
- Comment: Please rewritten the section of conclusion to make it in one passage and also
conclude that how the trigeneration system worked.
Response: The conclusion section was modified.
- Comment: Others; equations should be done in the same pattern as well as all nomenclature
should be added.
Response: All abbreviations used in equations are available in the nomenclature section.
Dear reviewer #1,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
Dear Sir, I have very thoroughly read and considered the manuscript ID as Sustainability2517954, entitle: "Using green energy sources in trigeneration to reduce environmental pollutants: Thermodynamic and Environmental Evaluation. This manuscript represents a novel dual-source trigeneration cycle based on a biogasfueled gas turbine and geothermal cycles and clean water production. For my opinion, I feel very satisfy for the results obtained together with objectives and a novel of work were achieved. Therefore, I have concluded that this article is accepted to public in Sustainability Journal.
Here they are, some more questions and comments;
- Comment: For the keyword of HDH, what is HDH stand for? and also in the abstract for the
technic term of EES software.
Response: The abbreviation of these words was added to the nomenclature section. However, HDH stands for humidification and dehumidfication, and EES stands for Engineering equation solver.
- Comment: For Fig.1 Schematic of trigeneration system, it should be better if the authors could improve whole Figure especially the labels should expand to make it clear. In addition a cited reference for the fig. should be added.
Response: The schematic of the proposed system was modified and improved in terms of quality. (Please see line 116 and line 118).
- Comment: The authors should discuss the capacity or the efficiency among 4 cycles of
trigeneration system.
Response: Table 4 shows the amount of energy efficiency, exergy efficiency and net output power of each system. (Please see line 262-269).
- Comment: 2-Figs.9, the authors should make more comparisons the results obtained and
Previous studies.
Response: In section 5, the comparative table of the present work with previous studies is shown. The results of this table show that the current proposed system is better.(please see conclusion section and table5).
- Comment: List of the main findings, indicated in the section of conclusion, should move to the
section of results and the authors should make a discussion for the results obtained
and make a comparison among previous studied.
Response: The list of main findings was added to the results and discussion section under the overall performance results title.
- Comment: Please rewritten the section of conclusion to make it in one passage and also
conclude that how the trigeneration system worked.
Response: The conclusion section was modified.
- Comment: Others; equations should be done in the same pattern as well as all nomenclature
should be added.
Response: All abbreviations used in equations are available in the nomenclature section.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article presents an interesting and innovative concept for a renewable energy system that combines geothermal power with a gas turbine, biogas, waste heat utilization, and freshwater production. Overall, it appears well-structured and provides a clear overview of the proposed system and its benefits.
1. Overall, the text is well-written, but it is suggested to improve the clarity and flow of the content.
2. It is suggested to include a more detailed cost-benefit analysis: While the proposed system appears promising from a thermodynamic perspective, it would be beneficial to conduct a detailed cost-benefit analysis. Assessing the economic feasibility and potential return on investment will help determine if the system is economically viable for implementation.
3. Environmental Impact Assessment: The paper mentions that biogas is considered a viable replacement for fossil fuels to mitigate pollutant gas emissions. However, a comprehensive environmental impact assessment of the entire system, including the extraction and utilization of biogas, is necessary to understand its true environmental benefits.
4. Real-World Performance Validation: To validate the theoretical results obtained using EES software, it is essential to conduct real-world performance tests on a small-scale prototype or pilot plant. This will provide more confidence in the system's efficiency and performance metrics. This recommendation may provide a better understanding of the proposed. If is not possible, it is recommended to state some real-world considerations in order to place the proposal into a more realistic scenario.
5. It is suggested to include some practical approaches to consider the safety and reliability of the proposal: The safety and reliability of the proposed system must be thoroughly evaluated. Operating multiple power cycles and heat recovery systems in tandem could present operational challenges and potential safety risks that need to be carefully managed.
6. In order to make use of quantitative approaches, it is suggested to mention some tools such as Life Cycle Assessment, to offer altiernatitves to comprehensively evaluate the sustainability of the proposed system, a life cycle assessment should be conducted. This assessment should consider the environmental impacts associated with the entire life cycle of the system, from material extraction to decommissioning.
Author Response
Dear reviewer #2,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
The article presents an interesting and innovative concept for a renewable energy system that combines geothermal power with a gas turbine, biogas, waste heat utilization, and freshwater production. Overall, it appears well-structured and provides a clear overview of the proposed system and its benefits.
- Comment: Overall, the text is well-written, but it is suggested to improve the clarity and flow of the content.
Response: We addressed your comment.
- Comment: It is suggested to include a more detailed cost-benefit analysis: While the proposed system appears promising from a thermodynamic perspective, it would be beneficial to conduct a detailed cost-benefit analysis. Assessing the economic feasibility and potential return on investment will help determine if the system is economically viable for implementation.
Response: Thank you. We are producing another article with economic and environmental analyses.
- Comment: Environmental Impact Assessment: The paper mentions that biogas is considered a viable replacement for fossil fuels to mitigate pollutant gas emissions. However, a comprehensive environmental impact assessment of the entire system, including the extraction and utilization of biogas, is necessary to understand its true environmental benefits.
Response: Thank you. We are producing another article with economic and environmental analyses.
- Comment: Real-World Performance Validation: To validate the theoretical results obtained using EES software, it is essential to conduct real-world performance tests on a small-scale prototype or pilot plant. This will provide more confidence in the system's efficiency and performance metrics. This recommendation may provide a better understanding of the proposed. If is not possible, it is recommended to state some real-world considerations in order to place the proposal into a more realistic scenario.
Response: Thank you. Unfortunately, due to theoretical analysis, we were not able to find a real power plant. However, we compared this present work with other similar studies, and the results depict the reliability of our study. Please notice the added Table 5.
- Comment: It is suggested to include some practical approaches to consider the safety and reliability of the proposal: The safety and reliability of the proposed system must be thoroughly evaluated. Operating multiple power cycles and heat recovery systems in tandem could present operational challenges and potential safety risks that need to be carefully managed.
Response: Thank you. We have studied the reliability of this system by monitoring the flue gas emission chart and the system’s overall performance. This system is an improvement compared to other similar studies, adding operational and maintenance simulation only deviates the study from its main goal which is a comprehensive thermodynamic evaluation.
- Comment: In order to make use of quantitative approaches, it is suggested to mention some tools such as Life Cycle Assessment, to offer alternatives to comprehensively evaluate the sustainability of the proposed system, a life cycle assessment should be conducted. This assessment should consider the environmental impacts associated with the entire life cycle of the system, from material extraction to decommissioning.
Response: Thank you. Utilizing renewable energy sources such as geothermal energy cycles and biogas is proven to be a very sustainable approach to power cycle designing. We will consider the life cycle assessment in our next study which is comprehensively evaluating this system’s economic and environmental aspects.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript was investigated a biogas-fueled gas turbine coupled with a double-expansion geothermal cycle for heat recovery, combustion product gases to run a Kalina cycle. EES software was applied to study the thermodynamic perspective, but no such details information in the methodology.
In general, the results and discussion need improvement in terms of technical writing and explanation. The current manuscript was insufficient of technical scientific discussion. Authors merely provided the trend of the results in section 4.1 modelling validation, section 4.2 system analysis as well as section 4.3 parametric study without a detailed exploration on the possible reasons for the trend that obtained. How each performance i.e. energy efficiency, exergy efficiency, net power output, CO2 emission index were determined? All these should be defined clearly in the methodology. Authors also did not provide the error bars for the results that obtained such as how many runs that authors conducted to obtain the performance values for trigeneration cycle.
Besides, the grammatical and structure English need significant improvement or at least checked by an English native speaker.
Need improvement. Significant structure or grammar mistakes could be spotted easily throughout the manuscript.
Author Response
Dear reviewer #3,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
Comment: The manuscript was investigated a biogas-fueled gas turbine coupled with a double-expansion geothermal cycle for heat recovery, combustion product gases to run a Kalina cycle. EES software was applied to study the thermodynamic perspective, but no such details information in the methodology. In general, the results and discussion need improvement in terms of technical writing and explanation. The current manuscript was insufficient of technical scientific discussion. Authors merely provided the trend of the results in section 4.1 modelling validation, section 4.2 system analysis as well as section 4.3 parametric study without a detailed exploration on the possible reasons for the trend that obtained. How each performance i.e. energy efficiency, exergy efficiency, net power output, CO2 emission index were determined? All these should be defined clearly in the methodology. Authors also did not provide the error bars for the results that obtained such as how many runs that authors conducted to obtain the performance values for trigeneration cycle.
Response: please notice the changes in yellow color throughout the manuscript.
Author Response File: Author Response.docx
Reviewer 4 Report
The novelty of this paper is not acceptable for publication in this journal.
The present paper is similar to many articles that have been published in this field and innovation is not seen in it.
The mentioned items regarding the presentation of a new system are not acceptable.
The background of the research is very weak and the recent works in this field have not been comprehensively and accurately reviewed
Research gaps are not stated correctly and the novelty is not mentioned properly.
In the results section, simple and very similar parameters have been examined with other works, and written results have not been presented
Therefore, due to the lack of sufficient justifications for the new cycle, the article is not accepted.
The quality of English Language is good.
Author Response
Dear reviewer #4,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript. The comments and our responses are as follows:
Comment: The novelty of this paper is not acceptable for publication in this journal.
The present paper is similar to many articles that have been published in this field and innovation is not seen in it.
The mentioned items regarding the presentation of a new system are not acceptable.
The background of the research is very weak and the recent works in this field have not been comprehensively and accurately reviewed
Research gaps are not stated correctly and the novelty is not mentioned properly.
In the results section, simple and very similar parameters have been examined with other works, and written results have not been presented
Therefore, due to the lack of sufficient justifications for the new cycle, the article is not accepted.
Response: We are sorry that this paper was not satisfactory for you. This system is a new approach to combining a biogas-fueled gas cycle with a double-expansion geothermal cycle as a secondary energy source as well as a heat recovery subject. We have compared the results of this study with other similar articles which show promising and interesting results at newly added Table 5. Written results in conjunction with a deeper discussion about the performance of the system are added in Table 4 and section 4.3.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
The comparative results with the literature should be presented in the section before conclusion i.e. section 5. Overall performance results. This section 5 should be presented in paragraph instead of point form. Some minor typo error i.e. comparesof could be spotted in the revised version of the manuscript.
Please check again the english grammar mistake. Some minor typo error i.e. comparesof could be spotted in the revised version of the manuscript.
Author Response
Dear reviewer #3,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript in yellow. The comments and our responses are as follows:
Comment: The comparative results with the literature should be presented in the section before conclusion i.e. section 5. Overall performance results. This section 5 should be presented in paragraph instead of point form. Some minor typo error i.e. comparesof could be spotted in the revised version of the manuscript.
Response: Thank you for your comments. We addressed the required changes, please notice section 5.
Comment: Please check again the english grammar mistake. Some minor typo error i.e. comparesof could be spotted in the revised version of the manuscript.
Response: Thank you for your comments. We have fixed some grammatical issues throughout the manuscript.
Reviewer 4 Report
The novelty of the present study in not enough.
The similar studies be done more than 6 recent years and I didn’t find any real novelty or contribution in this study. Therefore, I must reject it.
Author Response
Dear reviewer #4,
We appreciate your useful comments, which have helped us improve our manuscript. We carefully considered all the comments and addressed them appropriately in the manuscript in blue. The comments and our responses are as follows:
Comment: The novelty of the present study in not enough.
The similar studies be done more than 6 recent years and I didn’t find any real novelty or contribution in this study. Therefore, I must reject it.
Response: We are sorry that our work wasn’t satisfactory to you. We believe our present work has some interesting aspects in terms of the design and novelty of a multi-generation cycle, which is highlighted in section 1.
Round 3
Reviewer 4 Report
1. The novelty of this paper is not acceptable for publication in this journal. The respond of authors is not enough and no innovation has been seen in the paper. It is similar of many paper in this field.
2. literature review still is weak and not acceptable. There are many recent publication in this field and not mentioned correctly.
3. The results and sensitivity analysis are not acceptable as mentioned in the old comments.
4. Generally, due to lack of novelty, literature review, and quality of the results, I must reject the revised version.
