Environmental Impacts of Energy Saving Actions in an Academic Building

Round 1

Reviewer 1 Report

The paper discusses the environmental impacts of building environment and provides a case study of an educational building in Mexico and impacts from retrofitting lighting and air-conditioning. There are several issues with this paper. Firstly, the English is not appropriate for publication and needs considerable revision to align to the standards of international publications. The structure of the manuscript is as such that it has no Methods section, and the original research part is so small that it offers no level of innovation. The type of changes in the educational building are small, so the changes in the impacts are also small. There is no attempt to integrate solar, or provide changes to materials, which would give more extensive benefits. The results section presents "preliminary results" only. The journal Sustainability should not be used for publication of preliminary work and should include a more extensive work. The calculations are presented twice, once in a table and then as equations, which repeats what has already presented. Some of the parameters, such as those presented in Table 3 are for US conditions and not actual conditions of the power plant used to power the educational building. The conclusions are only 3 lines.

Author Response

Response to Reviewer 1

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic font and our replies are written in normal font. All the reviewers’ points and responses are included in the file.

Point 1: The paper discusses the environmental impacts of building environment and provides a case study of an educational building in Mexico and impacts from retrofitting lighting and air-conditioning. There are several issues with this paper. Firstly, the English is not appropriate for publication and needs considerable revision to align to the standards of international publications.

Response 1: We have made changes to the manuscript following the suggestions and queries raised by all the reviewers. We have also corrected some typos and language issues. We believe the paper is now improved. We hope it can be more understandable and hope that the reviewer finds it suitable for publication.

Point 2: The structure of the manuscript is as such that it has no Methods section. The original research part is so small that it offers no level of innovation. The type of changes in the educational building are small, so the changes in the impacts are also small.

Response 2: The method’s section is implicit in section 5. Specifically, it is located in the subsection Metrics of the project. On the other hand, the actions reported in this paper represent the first step in a project to become an energy-wise institution. We believe this is a valuable paper as it combines the lamp replacement with the implementation of a Building Automation and Control System. Moreover, the lamp replacement also includes a new lamp distribution that complies with the Mexican standard. Although these changes may seem small, the results show a significant impact in energy saving and the reduction on the emission of greenhouse gasses to the atmosphere (pollutants not sent to the atmosphere due to energy savings). We have included in the introduction and the conclusions sections some sentences in order to clarify this.

Point 3: There is no attempt to integrate solar, or provide changes to materials, which would give more extensive benefits.

Response 3: Thank you for your suggestion, we have included some of our plans to improve the impact of this project in the conclusion section. These plans include the integration of solar panels to generate clean energy, as long-term actions due to funding; and energy harvesting from the HVAC system.  

Point 4: The results section presents "preliminary results" only. The journal Sustainability should not be used for publication of preliminary work and should include a more extensive work.

Response 4: After looking at the comments of the reviewers we agree that the use of “preliminary results” is misleading. The original intention was to say that these were the first actions and that other actions would follow such as the generation of energy using other clean sources. We believe this paper presents extensive analysis in the retrofit actions and the implementation of the Building Automation and Control System. The analysis presented includes environmental impacts, indirect economic impacts, and direct economic impacts. Following Reviewer 2’s suggestion, we have also added the return of investment of the project in order to complement the analysis. In the revised paper we have rewritten some parts of the manuscript and we have suppressed the term “Preliminary” in order to avoid confusion.

Point 5: The calculations are presented twice, once in a table and then as equations, which repeats what has already presented.

Response 5: We have suppressed Table 1 of the first version of the paper in attention to this comment. The remaining tables do not display information/calculations that have already been presented as equations.

Point 6: Some of the parameters, such as those presented in Table 3 are for US conditions and not actual conditions of the power plant used to power the educational building.

Response 6: The reviewer is correct, the parameters presented in Table 3 (Table 2 of the revised paper) are for US Power Plants. These values were used because at the time of the drafting of the paper, no values for Mexico were found. However, further search in official Mexican websites provided data of the intake fraction values for Mexico.

Point 7: The conclusions are only 3 lines.

Respons 7: We have extended the conclusion section by adding discussion on the results and future work.

Author Response File: Author Response.pdf

Reviewer 2 Report

There are statements that are probably need referencing, and if those are authors opinions, it should be cleared in text (for ex. 107-109; 87-89, 115-117)

Referencing in some places should be corrected for ex line 59 I suggest [14-17]

section 2

I think general message of the section is interesting, but it might be so that it needs either re- arrangement with text or/and subheadings. I think at this stage the section feels unstructured and bit confusing.

line 208-212

I would like to propose that authors specify/clarify in this section why the energy consumption average/base line is being created in such a way. (the purpose)

line 225-229 it would be interesting if authors could specified the stages they refer to.

line 234-236 and the fig 5 - the figure is not informative. what are the energy goals exactly? how those solutions contribute to achieving the goals, how the mixed solutions are complementing each other? 

The authors are presenting calculations only for one site of the equation. The costs of the retrofit and operation must be taken under consideration. 

Conclusion section is rather short. I would suggest authors to bring more discussion  in this section.

Author Response

Response to Reviewer 2

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic and our replies are written in normal font. All the reviewers’ points and responses are included in the file.

Point 1: There are statements that are probably need referencing, and if those are authors opinions, it should be cleared in text (for ex. 107-109; 87-89, 115-117).

Response 1: Thank you for your comment we have added references where it applies and clarified where are the authors’ opinions.

Point 2: Referencing in some places should be corrected for ex line 59 I suggest [14-17].

Response 2: We have corrected it.

Point 3: Section 2. I think general message of the section is interesting, but it might be so that it needs either re-arrangement with text or/and subheadings. I think at this stage the section feels unstructured and bit confusing.

Response 3: We have added a paragraph at the beginning of this section in order to present its organization. We believe it is better structured and readable now.

Point 4: Line 208-212. I would like to propose that authors specify/clarify in this section why the energy consumption average/base line is being created in such a way. (the purpose).

Response 4: The energy base-line is calculated in this way in order to avoid taking into account the contribution of the air conditioners in the energy consumption. For this, the months where the air conditioners are not used were selected, there is regular occupation of the classrooms and the lighting is normally used.

Point 5: Line 225-229 it would be interesting if authors could specified the stages they refer to.

Response 5: The stages are (i) the retrofitting of the lighting, (ii) the implementation of a Building Automation and Control systems and (iii) the implementation of a robust power generation system. We have clarified this in the text.

Point 6: Line 234-236 and the fig 5 - the figure is not informative. what are the energy goals exactly? how those solutions contribute to achieving the goals, how the mixed solutions are complementing each other?

Response 6: The figure has been suppressed and we have included the energy goals and how the proposed solution contributes to them.

Point 7: The authors are presenting calculations only for one site of the equation. The costs of the retrofit and operation must be taken under consideration.

Response 7: Thank you very much for your observation. The reviewer is correct, there exists a cost for this retrofitting and the implementation of the Building Automation and Control System. In order to complement the direct economic impact, we have included the financial cost and the internal rate of return in the subsection 7.2.3.

Point 8: Conclusion section is rather short. I would suggest authors to bring more discussion in this section.

Response 8: We have extended the conclusion section by adding discussion on the results and future work.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper presents an example of energy renewal of an academic building. 

Renewal of lighting system and a BACS for controlling HVAC and lighting are proposed and evaluated for reducing the energy demand of the building. Moreover a calculation of the reduction of gaseous emission due to the expected energy savings is proposed, together with the consequent indirect cost reduction. 

The whole paper describes only a preliminary study for a single renewal work. 

The proposed energy renewal is presented in short. The proposed LED lighting system seems to be insufficient with a reduction of illumination near the walls. This is not discussed. 

The calculation of the indirect cost due to the HB through equations 10-13 is not discussed thoroughly.

Author Response

Response to Reviewer 3

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic and our replies are written in normal font. All the reviewers’ points and responses are included in the file.

Point 1: The paper presents an example of energy renewal of an academic building. Renewal of lighting system and a BACS for controlling HVAC and lighting are proposed and evaluated for reducing the energy demand of the building. Moreover, a calculation of the reduction of gaseous emission due to the expected energy savings is proposed, together with the consequent indirect cost reduction.

The whole paper describes only a preliminary study for a single renewal work. The proposed energy renewal is presented in short.

Response 1: The actions reported in this paper represent the first step in a project to become an energy wise institution. We believe this is a valuable paper as it combines the lamp replacement with the implementation of a Building Automation and Control System. Moreover, the lamp replacement also includes a new lamp distribution that complies with the Mexican standard norms. Although these changes may seem small, the results show a significant impact in energy saving and the reduction on the emission of greenhouse gasses to the atmosphere (pollutants not sent to the atmosphere due to energy savings). We have included in the introduction and the conclusions sections some sentences in order to clarify this.

On the other hand, after looking at the comments of the reviewers we agree that the use of “preliminary results” is misleading. The original intention was to say that these were the first actions and that other actions would follow such as the generation of energy using other clean sources. We believe this paper presents extensive analysis in the retrofit actions and the implementation of the Building Automation and Control System. The analysis presented includes environmental impacts, indirect economic impacts, and direct economic impacts. Following Reviewer 2’s suggestion we have also added the return of investment of the project in order to complement the analysis. In the revised paper we have rewritten some parts of the manuscript and we have suppressed the term “Preliminary” in order to avoid confusion.

Point 2: The proposed LED lighting system seems to be insufficient with a reduction of illumination near the walls. This is not discussed.

Response 2: In effect, the gray-shadowed area of the image is the region where the light is below 300 lx which is the minimum illumination level that should be in handling areas, classrooms, and offices according to the Mexican Standard NOM-025-STPS-2008. However, it does not mean that this area is dark, the room has a minimum illumination of 200 lx in the darkest point. Moreover, this less illuminated area is outside the working area, near the walls of the room as the reviewer correctly pointed out. This has been clarified in the text.

Point 3: The calculation of the indirect cost due to the HB through equations 10-13 is not discussed thoroughly.

Response 3: The estimation of the Health Benefits (HB) is based on the Harvard’s Six Cities Study by Dockery [43]. In this study, the authors estimated the effects of air pollution on mortality, while controlling for individual risk factors. Equations 10-13 are based in these estimated effects. We have clarified this in the text and put a reference for details.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have responded to a number of the comments but still need to address few other items:

Table 1 and Equation 8 present the same information and should be used either one or the other.

Table 3 has too many insignificant decimal points that need to be reduced.

Kg should be kg.

All chemical formulas should use the appropriate subheadings.

The Conclusions should be refined in its language and the use of scientific expressions.

Author Response

Response to Reviewer 1

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic font and our replies are written in normal font.

Point 1: The authors have responded to a number of the comments but still need to address few other items:

Table 1 and Equation 8 present the same information and should be used either one or the other.

Response 1: We have suppressed Table 1, and the sentence before the Table 1 was modified in order to have connection with equation (8). 

Point 2: Table 3 has too many insignificant decimal points that need to be reduced.

Response 2: Decimal points have been reduced in the numbers below 1,000; and they are eliminated in the numbers above 1,000.

Point 3: Kg should be kg.

Response 3: This has been corrected in equation (28), and all the manuscript was reviewed for other occurrences without other occurrences of this mistyping. 

Point 4: All chemical formulas should use the appropriate subheadings.

Response 4: All the chemical formulas used have been corrected.

Point 5: The Conclusions should be refined in its language and the use of scientific expressions.

Response5: We have revised the conclusions and polished the language and scientific expressions.

Author Response File: Author Response.pdf

Reviewer 2 Report

The presented project is interesting and caries a novelty value. 

I have just a minor comment:

line-69-75 I suggest authors explain why those 3 programs will be described in such detail. How those cases relate to the case study. 

Author Response

Response to Reviewer 2

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic and our replies are written in normal font.

Point 1: The presented project is interesting and caries a novelty value.

I have just a minor comment:

line-69-75 I suggest authors explain why those 3 programs will be described in such detail. How those cases relate to the case study.

Response 2: A paragraph has been added to address this comment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Author Response

Response to Reviewer 3

First of all, we would like to express our sincere gratitude to the anonymous reviewers for their valuable comments and recommendations. These comments have helped us to improve the new version of the manuscript. Hereafter, the reviewer comments are given in italic and our replies are written in normal font.

Point 1: The improvements made by the authors are not sufficient to overcome the issues that have been highlighted in the previous review. The explanation provided in the response letter are not included in the text. There are no results from the implementation. All data are from design calculations.

Response 1: We feel sorry but we do not fully understand what the reviewer is looking for here. In his/her past report on our paper, he/she raised three comments/queries that we answered in a response letter and, we surely modified the manuscript accordingly in order to make the ideas clearly. Now we will try to further improve these to the best of our understanding on what the reviewer might be looking for. These comments were:

(1)  The whole paper describes only a preliminary study for a single renewal work. The proposed energy renewal is presented in short.

(2)  The proposed LED lighting system seems to be insufficient with a reduction of illumination near the walls. This is not discussed.

(3)  The calculation of the indirect cost due to the HB through equations 10-13 is not discussed thoroughly.

The first comment was also a comment from Reviewer 1. In the response letter we explained the contribution of our paper, in the manuscript we emphasized the contributions in the abstract, the introduction and the conclusions. We also stated in the response letter that we agree that the term “Preliminary work” was misleading and therefore we eliminated that term from the manuscript and we left it as “Results”. We feel that this comment has been addressed in the first revision.

The second comment might be the one that the Reviewer 3 refers to when he/she says that “the explanation provided in the response letter is not included the text”. Therefore, we have extended this explanation in the paper in order to address this comment. We have basically explained that, although the gray-shadowed area of the image is the region where the light is below 300 lx which is the minimum illumination level that should be in handling areas, classrooms, and offices according to the Mexican Standard NOM-025-STPS-2008 the average lighting was above 300lx and this does not mean that this area is dark, the room has a minimum illumination of 200 lx in the darkest point. Moreover, this less illuminated area is outside the working area, near the walls of the room as the reviewer correctly pointed out.

For the third comment, in this second revised manuscript, we included a sentence to explain the nature of the equations 10-13 and we provided a reference. We still believe that this part of the manuscript should not get in deep discussion of these formulas and is better to refer to the reader to the original source.

Point 2: There are no results from the implementation. All data are from design calculations.

Response 2: Once again, we feel sorry because it seems we were not clear enough to state how the measurements of illumination and power consumptions were obtained; we included additional text describing that in section 5.1 and 6.1. Please note that the results are presented in Section 6 and Section 7. Specifically, Section 6 presents the implementation of the retrofit and the implementation of the BACS; Section 7 presents the results in terms of the environmental, (direct and indirect) economic impacts and following the Reviewer 2’s suggestion we also added the financial analysis.

Author Response File: Author Response.pdf

Round 3

Reviewer 3 Report

The revised version of the paper includes some improvements but is not sufficient. 

The whole research approach should be revised.

If measured results are available (energy consumption of each building and service), these should be clearly presented explaining the periods in which they were measured. Climate data and information on the use of the buildings should be provided for the same period, in order to evaluate the performance of the energy saving actions. 

I wasn’t able to find reference 43, so I can’t understand how eq. (12) is defined. In the equation, the reduction of concentration of pollutants is stated to be linear to the reduction of emission according to a so called “intake fraction of pollutant”. As far as I know (but it is not my main field of study) the variation in the concentration of a pollutant in a specific area depends on wind, rain and so on. So the proposed method is too simple to provide a trustable evaluation of indirect cost reduction due to energy savings. Moreover, the proximity of the power plant doesn’t imply that a reduction in energy consumption at the building would induce a reduction in power generation. The power may be generated elsewhere, or the generation may be reduced elsewhere, according to the management of the power grid. 

If the authors want to present a case study, they should provide more information on the design process and the way they chose and implemented the energy saving actions. So that other designers may use this experience. 

If the authors want to study the evaluation of indirect cost reduction due to energy saving actions, they should study (and proof) the method. 

At present the paper doesn’t provide enough details on the design of the energy saving actions. There are no data on the results of the actions. The explanation of the methods for the evaluation of the indirect costs reduction is not provided.