Selection of the Energy Performance Indicator for Hotels Based on ISO 50001: A Case Study
, Andrés Lorenzo Álvarez González 2, Juvenal Rodríguez-Reséndiz 3,* and José Manuel Álvarez-Alvarado 3,*Round 1
Reviewer 1 Report
This research aims to develop the energy performance indicator (EnPI) and Energy Baseline (EnB) for hotels in accordance with ISO 50001. The suggestions and comments for improving the study are as follows:
1- The latest version of ISO 50001 was published in 2018, thus ISO 50001:2019 is incorrect. The authors shall correct it throughout the paper.
2- Page 1, Line 6: Quadratic Correlation Coefficient is indicated by R. R2 (R-squared) represents the coefficient of determination.
3- The literature review should include related studies in the fields of EnMS, EnPI and EnB based on ISO 50001:2018. Also, the authors should clearly address and discuss how the EnMS requirements were developed in the introduction section and compare their study with existing research findings.
4- The main objective of the article is not clear. If the authors intend to cover two sections of the ISO 50001 i.e. energy review and energy performance indicator, they shall consider all the requirements of ISO 50001. For instance, the following requirements must be detailed for developing the energy review process:
a) analyze energy use and consumption based on measurement and other data.
b) based on the analysis, identify significant energy uses (SEUs);
c) for each SEU: 1) determine relevant variables; 2) determine current energy performance;
d) determine and prioritize opportunities for improving energy performance.
5- The materials and methods presented in this study (such as Figure 1 and Figure 2 and related statements) are based on the obsolete version of the standard (ISO 50001:2011). Therefore, it is not attractive and practical for the audience of this field.
6- The methods applied in the research for developing EnPIs and EnBs and related results are also based on the ISO 50001:2011. The authors can read and reference this article https://doi.org/10.1080/15567036.2021.2011989 for adjustment of the EnPIs. In accordance with ISO 50001:2018 the multivariable linear regression method can be used for developing EnPIs and EnBs in the case studies (hotels).
Author Response
We would like to thank the reviewers for their efforts and interest in our work. Your comments will improve the quality of this manuscript and give us the opportunity to clarify these comments. We will try our best to respond to all the comments raised by the reviewers.
We have carefully reviewed and attended to all comments raised by the reviewers, as listed below, highlighted in the manuscript.
Reviewer#1, Concern # 1: The latest version of ISO 50001 was published in 2018. Thus ISO 50001:2019 is incorrect. The authors shall correct it throughout the paper.
Author response: We appreciate your comment; The year of publication of the standard used in the text of the article was updated.
Author action: The year of publication of the standard used in the text of the article was updated.
Reviewer#1, Concern # 2: Page 1, Line 6: Quadratic Correlation Coefficient is indicated by R. R2 (R-squared) represents the coefficient of determination.
Author response: Thanks for your observation. The term quadratic coefficient of correlation was replaced by the coefficient of determination according to the suggestion given by the reviewer.
Author action: The term quadratic coefficient of correlation was replaced by the coefficient of determination according to the suggestion given by the reviewer in all the places where it was present in the article.
Reviewer#1, Concern # 3: The literature review should include related studies in the fields of EnMS, EnPI and EnB based on ISO 50001:2018. Also, the authors should clearly address and discuss how the EnMS requirements were developed in the introduction section and compare their study with existing research findings.
Author response: Thank you so much for the comments. The document was supplemented with information.
Author response: Texts and references were added in the introduction (lines 50-61) where what was requested by the reviewer is argued.
Also, We added a paragraph (lines 62-68) that review the disadvantages of not considering the indicators for energy performance as follows:
…Some studies based on the ISO 50001:2018 standard \cite{barrera2021propuesta, alvarado2021estrategias, duric2021role, salem2020energy, dibene2021energy}, where energy performance indicators are determined for hotel facilities, did not have into account the influence of the outside temperature, the differences between the rooms, services provided to non-guests, and differences between the services and activities offered to tourists. Although numerous studies demonstrated that parameters such as the level of occupancy and weather conditions strongly influence energy consumption, yet most indicators of energy efficiency discussed in the literature do not consider the outside temperature…
In addition, in the discussion section, a comparison is made of the indicators used in these types of studies with those obtained in this research (Table 1).
Reviewer#1, Concern # 4: The main objective of the article is not clear. If the authors intend to cover two sections of the ISO 50001 i.e. energy review and energy performance indicator, they shall consider all the requirements of ISO 50001. For instance, the following requirements must be detailed for developing the energy review process:
- a) analyze energy use and consumption based on measurement and other data.
- b) based on the analysis, identify significant energy uses (SEUs);
- c) for each SEU: 1) determine relevant variables; 2) determine current energy performance;
- d) determine and prioritize opportunities for improving energy performance.
Author response: We appreciate your observation. The introduction and results sections have been updated.
Author action: The objective of our research was rewritten for better clarity in the research topic in lines 73-75:
…For this context, this study aims to develop the stage of energy planning, including the implementation of an energy management system based on the standard ISO 50001:2018, to define the baseline and goal energy lines and the energy performance indicator. ..
Also, we explain the requested points as follows:
- a) In the results section, first, a description of the use and consumption of energy in the facility is made according to the equipment it has and the services it provides.
- b) According to Figures 3, 4, and 5, based on the Pareto diagrams, the most used energy carrier is identified and, in turn, the areas with the highest consumption of the same and it ends with an analysis using a graph of the consumption behavior of said carrier and the production variable, which in this case, being a hotel, is rooms occupied per day.
- c) Through figures 6,7,8, and 9, it was determined that the relevant variables are consumption and product RDO*DG. Which are justified by Table 1, which is compared with other indicators used in similar studies.
- d) In the results section, the savings opportunities are presented by areas. A lighting change proposal was also made with its respective economic analysis, and the use of renewable energy sources was proposed with a proposal for the sizing of a photovoltaic solar system on the roof of the building.
Reviewer#1, Concern # 5: The materials and methods presented in this study (such as Figure 1 and Figure 2 and related statements) are based on the obsolete version of the standard (ISO 50001:2011). Therefore, it is not attractive and practical for the audience of this field.
Author response: Thanks for the observation.
Author action: We consider that figures 1 and 2 are generic figures of the ISO 50001 standard. The objective of showing them is to give the reader an idea of which part occupies the planning stage within said standard and the other indicates how the stage is developed.
The text was added (lines 106-107) (Figure 1): As previously mentioned, the objective of the investigation is to focus on the planning stage, which can be seen reflected in the figure within the ISO 50001 standard.
The text (lines 107-111) was modified for a better understanding of figure 2.
Reviewer#1, Concern # 6: The methods applied in the research for developing EnPIs and EnBs and related results are also based on the ISO 50001:2011. The authors can read and reference this article https://doi.org/10.1080/15567036.2021.2011989 for adjustment of the EnPIs. In accordance with ISO 50001:2018 the multivariable linear regression method can be used for developing EnPIs and EnBs in the case studies (hotels).
Author response: We appreciate your observation. The objective of the research is to determine an energy performance indicator that presents a good correlation between its variables in comparison with other traditional indicators in this field that present lower correlations practically and simply.
Author action: The article recommended by the reviewer was cited in the text.
Reviewer 2 Report
Overall, the present work has enough contributions, the results are comprehensive with very good presentation. Only inaccuracy in the use of some mathematical terms is there. I recommend to change the Quadratic Correlation Coefficient (R2)" to the coefficient of determination R2.
Author Response
Reviewer#2, Concern # 1: Overall, the present work has enough contributions, the results are comprehensive with very good presentation. Only inaccuracy in the use of some mathematical terms is there. I recommend to change the Quadratic Correlation Coefficient (R2)" to the coefficient of determination R2.
Author response: Thanks for the observation. The term quadratic coefficient of correlation was replaced by the coefficient of determination according to the suggestion given by the reviewer.
Author action: The term quadratic coefficient of correlation was replaced by the coefficient of determination according to the suggestion given by the reviewer in all the places where it was present in the article.
Reviewer 3 Report
Introduction. The introduction needs to be more related to the research topic, it is too general. Other standards, methods and indicators that have been used to study energy management in hotels and what knowledge they have provided could be added. In this way, the contributions made by the research would be more noticeable and it would be understood why statistics were chosen for the analysis.
It is useful to add the motivation.
In materials and methods, it is convenient how the methodology will be followed and what new knowledge will be added. Figure 2 does not say how the diagnosis will be carried out and what methodology will be used to study the causes and effects of energy management. The hypotheses or objectives of the research need to be added.
Indicators are given but it is not clear whether they are appropriate for the research.
The metrics are very simple and it is not clear whether they are sufficient for the research.
A description of the process is missing.
Results. This section describes a case but does not observe an investigation. There is a need to apply some method or methodology that generates new knowledge with the correlations and indicators used.
As the method and objectives of the research are not clear, it is difficult to see if the results are relevant.
Discussion. Other characteristics of the papers could be identified in Table 1 to help identify, for example, which methods are used and how they manage energy. The application of the 50001 standard is not enough.
A more detailed, literature-based discussion is needed.
Conclusion. The conclusions need to be improved, as only results from the application of indicators are presented. How do these results generate new knowledge?
Bibliography. Select those that relate to the research.
Author Response
Reviewer#3, Concern # 1: Introduction. The introduction needs to be more related to the research topic, it is too general. Other standards, methods and indicators that have been used to study energy management in hotels and what knowledge they have provided could be added. In this way, the contributions made by the research would be more noticeable and it would be understood why statistics were chosen for the analysis. It is useful to add the motivation.
Author response: Thank you so much for the comments. The document was supplemented with information.
Author response: Texts and references were added in the introduction (lines 50-61) where what was requested by the reviewer is argued.
Also, We added a paragraph (lines 62-68) that review the disadvantages about not considering the indicators for energy performance as follows:
…Some studies based on the ISO 50001:2018 standard \cite{barrera2021propuesta, alvarado2021estrategias, duric2021role, salem2020energy, dibene2021energy}, where energy performance indicators are determined for hotel facilities, did not have into account the influence of the outside temperature, the differences between the rooms, services provided to non-guests, and differences between the services and activities offered to tourists. Although numerous studies demonstrated that parameters such as the level of occupancy and weather conditions strongly influence energy consumption, yet most indicators of energy efficiency discussed in the literature do not consider the outside temperature…
The objective of our research was rewritten for better clarity in the research topic in lines 73-75:
…For this context, this study aims to develop the stage of energy planning, including the implementation of an energy management system based on the standard ISO 50001:2018, to define the baseline and goal energy lines and the energy performance indicator. ..
Reviewer#3, Concern # 2: In materials and methods, it is convenient how the methodology will be followed and what new knowledge will be added. Figure 2 does not say how the diagnosis will be carried out and what methodology will be used to study the causes and effects of energy management. The hypotheses or objectives of the research need to be added. Indicators are given but it is not clear whether they are appropriate for the research. The metrics are very simple and it is not clear whether they are sufficient for the research. A description of the process is missing.
Author response: Thanks for the observation. We consider that figures 1 and 2 are generic figures of the ISO 50001 standard. The objective of showing them is to give the reader an idea of which part occupies the planning stage within the standard, and the other indicates how the stage is developed.
Author action: The text was added to lines 105-106 in Figure 1 as follows:
As previously mentioned, the objective of the investigation is to focus on the planning stage, which can be seen reflected in the figure within the ISO 50001 standard.
As previously mentioned, the objective of the investigation is to focus on the planning stage, which can be seen in Figure 1 within the ISO 50001 standard.
The text (lines 107-111) was modified for a better understanding of figure 2:
The methodology followed in this work is based on the planning stage of the ISO 50001 standard, see Figure 2, specifically focused on the energy review to analyze energy uses and consumption, identify areas of significant energy use, and identify the main opportunities for energy improvements. This figure is a synthesis of the standard at that stage, and a better understanding of it is expected.
We added the description of the performance process in lines 112-130.
Reviewer#3, Concern # 3: Results. This section describes a case but does not observe an investigation. There is a need to apply some method or methodology that generates new knowledge with the correlations and indicators used. As the method and objectives of the research are not clear, it is difficult to see if the results are relevant.
Author response: Thanks for the observation. The aim of the manuscript is to determine the energy performance indicator for hotel facilities that combines meteorological variables with traditional indicators in the sector. It obtained the correlation record with it, where it is defined through an analysis of the planning stage of the standard ISO 50001 applied to a case study. According to the literature consulted (specialized in the subject), the indicator is new and has very good results in its use.
Author action:
The objective of our research was rewritten for better clarity in the research topic in lines 73-75:
…For this context, this study aims to develop the stage of energy planning, including the implementation of an energy management system based on the standard ISO 50001:2018, to define the baseline and goal energy lines and the energy performance indicator...
Reviewer#3, Concern # 4: Discussion. Other characteristics of the papers could be identified in Table 1 to help identify, for example, which methods are used and how they manage energy. The application of the 50001 standard is not enough. A more detailed, literature-based discussion is needed.
Author response: Thanks for the observation.
Author action: In the Discussion section, Table 1 compares similar investigations that are based on the ISO 50001 standard, the most important factor, which is the energy performance indicator. It also highlighted its virtues and compared its deficiencies with others.
Reviewer#3, Concern # 5: Conclusion. The conclusions need to be improved, as only results from the application of indicators are presented. How do these results generate new knowledge?.
Author response: Thanks for the observation. The Conclusion section was improved.
Author action: We highlighted the limitations when performing this investigation and how we achieved the objective (430-437).
…In determining the energy performance indicator of this research, the limitation of the types of services provided by the hotel was detected, which are very varied, and it is highly complex to find an indicator that covers them. To cover this deficiency of indicators of this type, the variables with a greater correlation in consumption were sought, and that more encompassed the services provided by the hotel, considering the influence of the air temperature of the zone and the inner temperature by the air conditioning. By considering these variables, it is possible to determine the higher point of consumption of the installation, and the variable degrees days was introduced in the indicator…
Also, We mention future works on this topic in lines 446-449:
…This indicator serves as a base for future research, in which artificial intelligence techniques could be used, to more accurately predict its behavior over time, starting from it, new variables could also be introduced to cover more services and areas of the hotel and thus have a better correlation and reliability of the results to be obtained…
Reviewer#3, Concern # 6: Bibliography. Select those that relate to the research.
Author response: Thanks for the observation.
Author action: We reviewed and updated the bibliography with works related to the manuscript. All bibliographies used in the research are related to it. It has been added certain references along the Introduction Section to enhance this point.
Round 2
Reviewer 1 Report
Comments and suggestions are provided in the attached document.
Comments for author File: 
Comments.pdf
Author Response
Reply to the reviewer’s comments
We would like to thank the reviewers for their efforts and interest in our work. Your comments will improve the quality of this manuscript and give us the opportunity to clarify these comments. We will try our best to respond to all the comments raised by the reviewers.
We have carefully reviewed and attended to all comments raised by the reviewers, as listed below, highlighted in the manuscript.
Reviewer#1, Concern # 1: - In my opinion, in the revised manuscript, the materials and methods presented (such as Figure 1 and Figure 2 and related statements) are still based on the obsolete version of the standard (ISO 50001:2011). Therefore, the following Figures and statements are suggested for applying in the article, if desired.
Author response: We appreciate your comment; The text of the work was updated.
Author action: For a better understanding and adjustment of the ISO 50001:2011 standard to ISO 50001:2018, the text of lines 96 to 107 was modified. Figures 1 and 2 were also modified.
Reviewer#1, Concern # 2: The methods applied in the research for developing EnPIs and EnBs and related results are also based on the ISO 50001:2011. In accordance with ISO 50001:2018 the multivariable linear regression method can be used for developing EnPIs and EnBs in the case studies (hotels).
Thank you for your observation. Your proposal was taken into consideration, and the coefficient of determination was calculated using the multivariable linear regression method.
Author action: In the manuscript, section 3.2 was added where the analysis of the multivariable linear method for this hotel is carried out, where relevant results were obtained. It was exposed through tables 1 and 2, and figure 11 shows this behavior of the result. Table 3 was also modified, comparing the new results, and a bibliography on the subject was added.
Reviewer#3, Concern # 1: Introduction. The motivation is still not well understood, nor how new knowledge is generated with the application of ISO 50001:2018 in the pilot case. It adds the objective and more references but it is not understood why research in this area is needed nor what is the contribution.What other mathematical methods can be applied?
Author response: Thank you so much for the comments. The document was supplemented with information.
Author Action: A text was added to the introduction with the most used mathematical methods in this field and references in this regard (lines 73-76):
…..The analysis of variance are methods typical of the experimental designs. They allow us to know if there is a dependency relationship between the variables under study, and they allow us to know the statistical significance of the factors involved in each energy performance index \cite{torres2021modelos,laayati2020smart}......
The objective was modified by restructuring the text of lines 77-81:
…….For this context, this study aims to develop the energy planning stage, including the implementation of an energy management system based on the ISO 50001:2018 standard, to define the baseline and energy goal and, from this propose an indicator of energy performance with a high correlation between its variables, which allows evaluating the energy consumption of the company and predicting its behavior………
In the manuscript, section 3.2 was added, where the analysis of the multivariable linear method for this hotel is carried out where relevant results were obtained, it was exposed through tables 1 and 2, and figure 11 shows this behavior of the result. Table 3 was also modified, comparing the new results and adding a bibliography on the subject.
Reviewer 3 Report
1. Introduction. The motivation is still not well understood, nor how new knowledge is generated with the application of ISO 50001:2018 in the pilot case. It adds the objective and more references but it is not understood why research in this area is needed nor what is the contribution.What other mathematical methods can be applied?
2. Figure 1. The PDCA stages are general, it would be convenient to add more detail and specify which are the ones to be studied in the work.
3. In materials and methods it is not necessary to list so many sub-sections. In the description of the hotel, the process with its stages could be included, so that the problem and the need to apply metrics would be better understood.
4. It remains to be said from where or what method is used to extract the data for the graphs and what is the sample. Do all hotels using this standard have the same energy management? It gives the impression that a particular case is studied.
5. Calculating the correlation alone is not enough; hypothesis tests or other methods could be applied.
6. In 3.2, the risks or impacts that generate advantages and disadvantages for energy management could be added. Only advantages are written. In addition, it is necessary to explain how they generate benefits and why these factors are chosen for the analysis.
If a process had been added, this part would be better understood.
7. Discussion. Other characteristics of the papers could be identified in Table 1 to help identify, for example, which methods are used and how they manage energy. The application of the 50001 standard is not enough. A more detailed, literature-based discussion is needed.
8. It is necessary to add conclusions that show how new knowledge is generated, only an analysis of indicators and correlation is observed.
Author Response
Reply to the reviewer’s comments
We would like to thank the reviewers for their efforts and interest in our work. Your comments will improve the quality of this manuscript and give us the opportunity to clarify these comments. We will try our best to respond to all the comments raised by the reviewers.
We have carefully reviewed and attended to all comments raised by the reviewers, as listed below, highlighted in the manuscript.
Reviewer#3, Concern # 2: Figure 1. The PDCA stages are general, it would be convenient to add more detail and specify which are the ones to be studied in the work.
Author response: We appreciate your comment; The text of the work was updated.
Author action: For a better understanding and adjustment of the ISO 50001:2011 standard to ISO 50001:2018, the text of lines 96 to 107 was modified. Figures 1 and 2 were also modified.
Reviewer#3, Concern # 3: In materials and methods it is not necessary to list so many sub-sections. In the description of the hotel, the process with its stages could be included, so that the problem and the need to apply metrics would be better understood.
Author response: We appreciate your comment; The text of the manuscript was updated.
Author action: The text of lines 121-141 was modified for a better comprehension of the process carried out. Also, an update of the new results was obtained.
The materials and methods section was restructured where its sections were eliminated, figure 3 was added for a better understanding of the process carried out and consequently the text of line 155.
Reviewer#3, Concern # 4: It remains to be said from where or what method is used to extract the data for the graphs and what is the sample. Do all hotels using this standard have the same energy management? It gives the impression that a particular case is studied.
Author response: Thanks for the observation. In the manuscript it is mentioned that the data obtained are measurements made in the hotel, said facility has a database to which we were given access for said study
Author action: In lines 179-193 that the data obtained are measurements made in the hotel, said facility has a database to which we were given access for said study. We base ourselves on ISO 50001 as it is the international standard norm that governs energy management, for which the energy performance indicator obtained is valid for any hotel facility, as well explained in the research.
Reviewer#3, Concern # 5: Calculating the correlation alone is not enough; hypothesis tests or other methods could be applied.
Author response: Thank you for your observation. Your proposal was taken into consideration and the coefficient of determination was calculated using the multivariable linear regression method.
Author action: The correlation analysis between the variables in question was carried out using two RDO and DG 0.90 were obtained. In the manuscript, section 3.2 was added where the analysis of the multivariable linear method for this hotel is carried out, where relevant results were obtained, it was exposed through tables 1 and 2, figure 11 shows this behavior of the result. Table 3 was also modified comparing the new results and bibliography on the subject was added.
Reviewer#3, Concern # 6: In 3.2, the risks or impacts that generate advantages and disadvantages for energy management could be added. Only advantages are written. In addition, it is necessary to explain how they generate benefits and why these factors are chosen for the analysis. If a process had been added, this part would be better understood.
Author response: Thanks for the observation. Regarding the impact that these savings opportunities will have directly on the energy consumption of the company and consequently on the economy of the company, these opportunities are proposed with a positive character and only the economic analysis of the lighting change is carried out, which It would bring economic and environmental advantages for the company, in turn the proposal of a photovoltaic solar system is made.
Author action: These factors were selected because they are the ones that most influence the company's consumption as shown in the Pareto principle and in the new figure 3 that was added.
Reviewer#3, Concern # 7: Discussion. Other characteristics of the papers could be identified in Table 1 to help identify, for example, which methods are used and how they manage energy. The application of the 50001 standard is not enough. A more detailed, literature-based discussion is needed.
Author response: Thanks for the observation. Modified the discussion section.
Author action: Table 1, which is now table 3, was modified, references and new columns were added for a better comparison.
Reviewer#3, Concern # 8: It is necessary to add conclusions that show how new knowledge is generated, only an analysis of indicators and correlation is observed.
Author response: Thanks for the observation. Modified the conclusions section.
Author action: The conclusion section was updated to highlight the new generated knowledge and the novelty of the work.
Round 3
Reviewer 1 Report
The authors made the suggested corrections. From my point of view, paper can be considered for publishing.
Reviewer 3 Report
I notice that an effort has been made to improve the paper, congratulations.
