A Novel Electricity and Freshwater Production System: Performance Analysis from Reliability and Exergoeconomic Viewpoints with Multi-Objective Optimization

Round 1

Reviewer 1 Report

Dear Authors,
thanks for your contribution firstly. The paper provides an exergoeconomic, reliability and optimization analysis of a combined electricity and freshwater production system.
The abstract is well written, it briefly summarizes the purpose of the article, the methods used and the results obtained.
However, although I believe that the paper includes solid content, but the presentation need to be improved, with better structure this manuscript can have its own value and impact. It could be better reorganized by distributing the various paragraphs in the chapters: Introduction / Materials & Methods / Results / Discussion / Conclusions.
For example, I suggest moving the "System description", "Modeling and Assumptions" and "Validation" part within the Materials and Methods section.
Also, the text inside the tables is entirely bold; I suggest leaving only the row / column names in bold.
The figures on the other hand are clear and I like that the conclusions are in a bulleted list.
Finally, I suggest to insert a small paragraph in the introductions that deals the efforts made in the literature of the various sustainable renewal proposals made by researchers in order to make the water infrastructure more efficient, self-sufficient and respectful of the environment; in this way you could further enrich the references of your paper. To this end I suggest the following studies, the first describes different energy production, recovery and saving measures which can be applied in an integrated urban water system (https://doi.org/10.1063/1.5012471) while the second and third present a decision support tool able to analyze the water and energy balance in the water service, in order to achieve a sustainable use of water and energy resources (DOI: 10.1021 / acs.est.6b01559; https://doi.org/10.1016/j .proeng.2015.08.952).
In conclusion, re-organize the content and improve the structure, it can be a good publication. I hope that these recommendations are helpful to the authors and wish good luck for the further reviewing process.

Author Response

Reviewer #1:

Dear Authors,

Thanks for your contribution firstly. The paper provides an exergoeconomic, reliability and optimization analysis of a combined electricity and freshwater production system.
The abstract is well written, it briefly summarizes the purpose of the article, the methods used and the results obtained.

We thank the respected reviewer for the comments that he/she raised that helped us to enhance the quality of the paper.

However, although I believe that the paper includes solid content, but the presentation need to be improved, with better structure this manuscript can have its own value and impact. It could be better reorganized by distributing the various paragraphs in the chapters: Introduction / Materials & Methods / Results / Discussion / Conclusions. For example, I suggest moving the "System description", "Modeling and Assumptions" and "Validation" part within the Materials and Methods section. Also, the text inside the tables is entirely bold; I suggest leaving only the row / column names in bold.

Response: Thank you for pointing this out. As you recommended, the structure of the paper is modified. Also, the bold sections in the tables are modified.

The figures on the other hand are clear and I like that the conclusions are in a bulleted list.
Finally, I suggest to insert a small paragraph in the introductions that deals the efforts made in the literature of the various sustainable renewal proposals made by researchers in order to make the water infrastructure more efficient, self-sufficient and respectful of the environment; in this way you could further enrich the references of your paper. To this end I suggest the following studies, the first describes different energy production, recovery and saving measures which can be applied in an integrated urban water system (https://doi.org/10.1063/1.5012471) while the second and third present a decision support tool able to analyze the water and energy balance in the water service, in order to achieve a sustainable use of water and energy resources (DOI:10.1021/ acs.est.6b01559; https://doi.org/10.1016/j .proeng.2015.08.952).

Response: Thank you for pointing this out. As you recommended, the proposed papers in a separate paragraph are added to the revised manuscript.

In conclusion, re-organize the content and improve the structure, it can be a good publication. I hope that these recommendations are helpful to the authors and wish good luck for the further reviewing process.

Thank you for positive insight over the proposed manuscript.

Reviewer 2 Report

The authors propose “Availability, reliability, and exergoeconomic analysis and multi-objective optimization of novel electricity and freshwater production system.” The title should be concise and reflect the main contribution of this work. The term novel should be brought at the beginning part of the title. For example, “A novel electricity and freshwater production system and its availability, reliability, exergoeconomic analysis with multi-objective optimization ”. Also, the term availability does not fit with the title. Please recheck and rewrite the appropriate title.  

 

1. The novelty is not clearly mentioned in the abstract. Please write at least 2/3 sentences to describe the novelty of the work. Most of the abstract part discusses the results. The authors should, instead, discuss the novelty and methodology.
2. Artificial neural network (ANN), the multi-objective particle swarm optimization (MOPSO) algorithm, biomass gasification system, electricity production, and freshwater production are not novel things. Thus, the authors must clearly show the novelty of the work.
3. The introduction section is very long. Some paragraphs are too long. The first paragraph of the introduction section discusses the aspect of renewable energy integration which is incomplete as the challenges and solutions of renewable energy are not discussed well. Please check the reference: 1109/ACCESS.2020.3031481 Also, The section “1.1. Main novelties and contributions” is still unable to show the novelty. Since hybridizing several methods is not a novelty. Please update this section.
4. Many terms in the equations are not defined. All the equations and the related terms should be updated accordingly.
5. The optimization flowchart in Fig. 4 should be given separately in another Figure.
6. The practical aspect of the proposed approach should be discussed? Is it possible to implement it in practice? If so, please add a cost analysis of the proposed method. Then, compare the cost-benefit with the existing methods.
7. Grammatical and spelling should be rechecked. 

Overall, the topic presented is interesting. However, the authors are requested to put effort to rebuild the work in order to show the novelty clearly.  

Author Response

Reviewer #2:

The authors propose “Availability, reliability, and exergoeconomic analysis and multi-objective optimization of novel electricity and freshwater production system.” The title should be concise and reflect the main contribution of this work. The term novel should be brought at the beginning part of the title. For example, “A novel electricity and freshwater production system and its availability, reliability, exergoeconomic analysis with multi-objective optimization”. Also, the term availability does not fit with the title. Please recheck and rewrite the appropriate title.  

1. The novelty is not clearly mentioned in the abstract. Please write at least 2/3 sentences to describe the novelty of the work. Most of the abstract part discusses the results. The authors should, instead, discuss the novelty and methodology.

Response: Thank you for your detailed comments on our presented manuscript. As you recommended, the “Abstract” section is modified, and the main novelties, contributions, and methodologies are mentioned.

2. Artificial neural network (ANN), the multi-objective particle swarm optimization (MOPSO) algorithm, biomass gasification system, electricity production, and freshwater production are not novel things. Thus, the authors must clearly show the novelty of the work.

Response: Thank you for raising this point. We confirm that the proposed system may not be a novel system simultaneous power and drinkable water production, but as described in the manuscript, the devised system's main novelties lie in the integration of biomass gasification and a regenerative gas turbine with intercooling and a syngas combustor, where the syngas produced in the gasifier is burnt in the combustion chamber and directly fed to a gas turbine. In most previously published papers, the combusted syngas is used indirectly through heat recovery systems for various commodity production aims. Also, in the devising our proposed system, we considered the applicability of the plant in the real-world for construction. Most of the works presented in this field are conceptual. 

Also, despite various studies on IGCC-based cogeneration systems from multiple viewpoints, the availability and reliability of IGCC-based cogeneration plants have not been studied extensively. Accordingly, a discrete Markov process model to analyze the reliability and availability of the target system is developed.

3. The introduction section is very long. Some paragraphs are too long. The first paragraph of the introduction section discusses the aspect of renewable energy integration which is incomplete as the challenges and solutions of renewable energy are not discussed well. Please check the reference: 1109/ACCESS.2020.3031481 Also, The section “1.1. Main novelties and contributions” is still unable to show the novelty. Since hybridizing several methods is not a novelty. Please update this section.

Response: Thank you! As you mentioned, the first paragraph of the introduction is modified and the proposed paper is added to discuss the aspects of using renewable energies.

Moreover, as mentioned earlier, the novelty of proposed system is the integration of biomass gasification and a regenerative gas turbine with intercooling and a syngas combustor, where the syngas produced in the gasifier is burnt in the combustion chamber and directly fed to a gas turbine. Mostly, the combusted syngas is used indirectly through heat recovery systems for various commodity production aims. Also, in the devising our proposed system, we considered the applicability of the plant in the real-world for construction. Most of the works presented in this field are conceptual. 

4. Many terms in the equations are not defined. All the equations and the related terms should be updated accordingly.

Response: Thank you for pointing this out. It’s been tried to define all terms in the equations in the revised manuscript.

5. The optimization flowchart in Fig. 4 should be given separately in another Figure.

Response: Thank you! As you recommended, Fig. 4 is separated into two figures; a) Schematic diagram of the modeling and optimization process, and b) MOPSO flowchart.

6. The practical aspect of the proposed approach should be discussed? Is it possible to implement it in practice? If so, please add a cost analysis of the proposed method. Then, compare the cost-benefit with the existing methods.

Response: Thank you! In the designing of the proposed system, the complexity of the plant is not concerned, but the practicality matters. As mentioned earlier, the proposed system can be constructed in real-world applications since the sustainability and renewability of the energy source is a big concern. The management of biomass ((such as microalgae, crop residues, animal waste, food processing waste, municipal solid waste, sludge waste, and wood­wood waste) is a big concern today for city authorities and planners due to increasing population, urbanization, and limited land space. MSW is one of the major concerns to environmental health. The traditional treatment and dumping of solid waste have some key environmental challenges, such as leachate generation and air pollution. Such environmental challenges, combined with political, social, and economic issues and the availability of land, are major concerns to be addressed in land evaluation and management. On the other hand, increasing population leads to increased fossil fuel consumption and the corresponding increase in energy and fuel demands and greenhouse gas (GHG) emissions. Converting biomass to energy provides an option to produce cleaner energy and contributes to offsetting GHG emissions. Also, renewable energy generation systems are considered clean and cheaper compared to traditional power generation systems. Thus, governments and several agencies are forced to increase the renewable energy generation to replace fossil fuel-based power generation. However, the efficiency of the fossil fuel-based power generation systems may be higher than the renewable energy generation systems.

Moreover, since the proposed system is analyzed from different aspects and economic aspects, the economic analysis may not represent itself in the results. The proposed system is analyzed from the economic viewpoint and the results of which are presented in the SUCP index. The unit cost of production by onshore wind power plants, in geothermal and hydropower, and based on biomass is equal to or lower than the cost of generation at coal, gas and diesel power plants, even without financial support and with falling oil prices.

Also, The sum unit cost of products (SUCP) for the proposed cycle is evaluated as , which is lower than compared works: 1. https://doi.org/10.1016/j.energy.2021.119980 by , and 2. https://doi.org/10.1016/j.jclepro.2020.125639 by .

7. Grammatical and spelling should be rechecked. 

Response: Thank you! grammatical and spelling errors are addressed in the revised manuscript.

Overall, the topic presented is interesting. However, the authors are requested to put effort to rebuild the work in order to show the novelty clearly.  

Thank you for positive insight over the proposed manuscript.

 

Round 2

Reviewer 1 Report

Dear Authors,

the suggested changes have been made.  In my opinion, now, the paper is ready for publication.

Author Response

We thank the respected reviewer for the comments that he/she raised that helped us to enhance the quality of the paper. 

Reviewer 2 Report

The authors propose “Availability, reliability, and exergoeconomic analysis and multi-objective optimization of novel electricity and freshwater production system.” The following comments have not been addressed properly.

1. The title should be concise and reflect the main contribution of this work. The term novel should be brought at the beginning part of the title. For example, “A novel electricity and freshwater production system and its availability, reliability, exergoeconomic analysis with multi-objective optimization”. Also, the term availability does not fit with the title. Please recheck and rewrite the appropriate title.

Author Response

Reviewer #2:

Dear Authors,

The authors propose “Availability, reliability, and exergoeconomic analysis and multi-objective optimization of novel electricity and freshwater production system.” The following comments have not been addressed properly.

We thank the respected reviewer for the comments that he/she raised that helped us to enhance the quality of the paper.

1. The title should be concise and reflect the main contribution of this work. The term novel should be brought at the beginning part of the title. For example, “A novel electricity and freshwater production system and its availability, reliability, exergoeconomic analysis with multi-objective optimization”. Also, the term availability does not fit with the title. Please recheck and rewrite the appropriate title.

Response: Thank you for pointing this out. As you recommended, the title is modified to “A novel electricity and freshwater production system; Performance analysis from reliability and exergoeconomic viewpoints with multi-objective optimization”.