Optimization of Heat Pump Systems in Buildings by Minimizing Costs and CO₂ Emissions

Round 1

Reviewer 1 Report

1.       More latest research works are recommended to be added in the literature.

2.       There are too many references come from website which is not recommended.

3.       The authors are suggested to simplified and make a conclusion of the assumptions at the end of Section 3.2. The description of assumption is too long. Please point out what kind of assumptions are made in the model.

4.       The model validation is required for the proposed model.

5.       The more specific description of the results for the figures need to be added. What is the comparing results between renovated and unrenovated buildings?

6.       The figures in the results need more explanations. How much does the EHs power consumption account for the total energy consumption?

7.       The colour distinction in the figures is not enough.

8.       The discussion and results are suggested to be combined.

9.       The key findings are suggested to be listed in conclusions.

Author Response

Dear Reviewer,

We are grateful for your supportive comments on this work, and for agreeing to review a particularly long and detailed manuscript. We would like to express our sincere appreciation for reading this paper. The authors have revised the present paper according to the reviewer’s valuable suggestions and comments. The authors hope their revision has improved the paper to a level of reviewer’s satisfaction. In the following, the comments from the reviewer are provided in the box with our responses and changes below the box. Our responses are as follows.

 

1. More latest research works are recommended to be added in the literature.

Response:

As suggested by the reviewer, some latest relevant references were included in the revised manuscript. However, it should be noted that almost 80% of the references are from academic papers published within the last 5 years.

 

2. There are too many references come from website which is not recommended.

Response:

The references from websites include information from official European Commission sites, and some references serve as sources for the data and assumptions used in the simulations. However, all relevant references used in the literature review are taken from academic papers published in journals with citation indexes, and not from websites, which, in authors’ opinion, is sufficient.

 

3. The authors are suggested to simplified and make a conclusion of the assumptions at the end of Section 3.2. The description of assumption is too long. Please point out what kind of assumptions are made in the model.

Response:

The detailed and long description of assumptions used in the simulation has two reasons. First, the proposed model is composed of many constraints and variables, so in order to justify them, the assumptions were extensively described. Second, the readers of the paper might not be experts in the field. To make the assumptions understandable to a wider audience, an effort was made to provide detailed description of these assumptions. Therefore, the authors would like to keep Subsection 3.2. as it is.

 

4. The model validation is required for the proposed model.

Response:

The authors agree that model validation is an important aspect of any modelling study. However, in this particular case, to the best of authors’ current knowledge, no similar models have been created or published in the academic literature. Additionally, there is no experiment made in the buildings of the case study against which the authors can compare the results of the proposed model. Therefore, the authors cannot perform model validation in the traditional sense.

However, a comparison of the proposed model results with the actual data was performed in the revised manuscript by emphasizing the savings in operating costs that can be achieved by using the proposed heating system instead of the district heating.

The authors hope that this clarifies the proposed approach and demonstrates the validity of the proposed model to the extent possible given the constraints of the study.

 

5. The more specific description of the results for the figures need to be added. What is the comparing results between renovated and unrenovated buildings?

Response:

As suggested by the reviewer, more specific descriptions of the results in the figures were added where appropriate.

 

6. The figures in the results need more explanations. How much does the EHs power consumption account for the total energy consumption?

Response:

As suggested by the reviewer, more specific descriptions of the results in the figures were added where appropriate.

 

7. The colour distinction in the figures is not enough.

Response:

The figures in the Results Section were revised.

 

8. The discussion and results are suggested to be combined.

Response:

The guidelines for authors and the template of the journal paper recommend to include Discussions Section as a separate Section. Additionally, Discussions Section in the paper is quite long, thus joining it with the Results Section will make it too extensive. Therefore, the authors would like to keep the Discussion Section as it is.

 

9. The key findings are suggested to be listed in conclusions.

Response:

The authors would like to keep the conclusions section as a text that provides a clear and concise summary of the paper’s main results, rather than simply listing the key findings. The reason for this is that the conclusions section should serve as a summary of the paper’s main arguments and results, and should not simply restate what has already been presented in the discussion or results sections. Listing the key findings in the conclusions section would not provide any new information or insight for the reader. Instead, the authors believe that the conclusions section should be a cohesive and logical text that ties together the results presented in the paper and provides the reader with a clear understanding of the significance and implications of the research.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper proposes a method to optimize heat pump operation in order to minimize cost and CO2 emissions. The paper is well-organized and presented clearly, and appropriate references are included. However, there are some comments that can be found below:  

1.      It is important to provide a clear source for any equations used in the paper. If an equation is derived from a specific reference, please provide the reference. If the equation is derived by the author, please explain the derivation in the paper. This will help readers better understand the reasoning behind the equations used in the paper.

 

2.      Including a diagram of the considered system in Section 3 would be helpful to readers. A diagram can help to illustrate the various components of the system and how they interact with each other. This can make it easier for readers to follow the discussion in the paper and understand the proposed method

 

3.      Providing more detailed names for each section can help to give readers a better idea of what to expect in each section. For example, instead of simply labeling a section "Method," consider labeling it "Proposed Method for Optimizing Heat Pump Operation." This can help to make the paper more organized and easier to navigate.

 

4.      All abbreviations and notations should be introduced at the beginning of paper.

 

5.      Because you proposed a method to optimize the heat pump operation, it would be useful to compare the effectiveness of the proposed algorithm with similar methods.

Other than that, the paper should be good to be published.

Author Response

Dear Reviewer,

 

We are grateful for your supportive comments on this work, and for agreeing to review a particularly long and detailed manuscript. We would like to express our sincere appreciation for reading this paper. The authors have revised the present paper according to the reviewer’s valuable suggestions and comments. The authors hope their revision has improved the paper to a level of reviewer’s satisfaction. In the following, the comments from the reviewer are provided in the box with our responses and changes below the box. Our responses are as follows.

 

The paper proposes a method to optimize heat pump operation in order to minimize cost and CO2 emissions. The paper is well-organized and presented clearly, and appropriate references are included. However, there are some comments that can be found below:

Response:

The authors would like to extend their gratitude to the reviewer for the comments. They have made every effort to improve the clarity and quality of the manuscript. Responses to the specific reviewer‘s comments are provided further.

 

1. It is important to provide a clear source for any equations used in the paper. If an equation is derived from a specific reference, please provide the reference. If the equation is derived by the author, please explain the derivation in the paper. This will help readers better understand the reasoning behind the equations used in the paper.

Response:

The authors confirm that the goal functions and constraint inequalities used in the manuscript were derived by the authors. However, the methodology used is based on classical optimization problem theory, but was applied to the particular task and problem being solved. Additionally, some references have been added in the Methodology Section to clarify the methods used.

 

2. Including a diagram of the considered system in Section 3 would be helpful to readers. A diagram can help to illustrate the various components of the system and how they interact with each other. This can make it easier for readers to follow the discussion in the paper and understand the proposed method

Response:

The main focus of the proposed model is to minimize the costs and reduce the CO₂ emissions of the heating system. However, the model does not examine the detailed operations and processes of heat pump and electric heater technologies, for which a diagram with various components could be an option. The primary aim of the model is to optimize the selection of heat pumps and electric heaters, such as determining which heat pumps operate in the most cost-effective and environmentally friendly way while meeting the heat demand. However, a thorough technological operation with various components of the proposed heating system is not analysed.

Additionally, the case study includes 11 different buildings, each of which may have a different installed heating system. Thus, the diagram for each building may also differ. Providing a diagram for each analysed case would not be an option.

 

3. Providing more detailed names for each section can help to give readers a better idea of what to expect in each section. For example, instead of simply labeling a section "Method," consider labeling it "Proposed Method for Optimizing Heat Pump Operation." This can help to make the paper more organized and easier to navigate.

Response:

The authors have used the recommended titles for Sections from the journal template, such as Introduction, Methodology, Results, Discussion, Conclusion, etc. which are commonly used in scientific papers. To improve navigation, the titles for Subsections only were revised in the revised manuscript.

 

4. All abbreviations and notations should be introduced at the beginning of paper.

Response:

As suggested by the reviewer, a list of abbreviations was included in the revised manuscript. However, the guidelines for authors and the template of the journal paper require that the list of abbreviations be included at the end of the paper, not at the beginning.

 

5. Because you proposed a method to optimize the heat pump operation, it would be useful to compare the effectiveness of the proposed algorithm with similar methods.

Response:

It should be noted that the main focus of the proposed model is to optimize not a heat pump operation, but to optimize (minimize) the costs and reduce the CO₂ emissions of the heating system with heat pumps and electric heaters. This reflects to a problem of the optimal selection of heat pumps and electric heaters, such as determining which heat pumps operate in the most cost-effective and environmentally friendly way while meeting the heat demand.

The authors agree that it would be useful to compare the effectiveness of the proposed model with similar model which is an important aspect of any modelling study. However, in this particular case, to the best of authors’ current knowledge, no similar models have been created or published in the literature. Additionally, there is no experiment installed in the buildings of the case study against which the authors can compare the results of the proposed model. Therefore, the authors cannot perform model validation in the traditional sense.

However, a comparison of the proposed model results with the actual data was performed in the revised manuscript by emphasizing the savings in operating costs that can be achieved by using the proposed heating system instead of the district heating.

The authors hope that this clarifies the proposed approach and demonstrates the validity of the proposed model to the extent possible given the constraints of the study.

 

Other than that, the paper should be good to be published.

Response:

The authors thank for the positive comment.

Author Response File: Author Response.docx