Multi-Energy Interplay in a Planned District Community with a Large Share of PV-Produced Electricity in a Nordic Climate
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors- Resaerch gaps need to explored further
2.Operative household energy demand and its estimation can be shown by a flow chart for the better understanding for the readers.
3.All abbreviations used should be included in the nomenclature section.
- Methodology section that is section 4 should be made concise and to be restructured for better readability
- Resolution of Figure 4 needs improvement.
5.the entire paper looks as a report rather than a journal paper. drawbacks of the system for nighttime and rainy days, and other shortcomings should be discussed.
6. Conclusions should be made concise and can be bullet-pointed rather than explained
Author Response
- Research gaps need to explored further
Response: Research gaps have been identified to highlight the significance of this manuscript and its uniqueness.
2.Operative household energy demand and its estimation can be shown by a flow chart for the better understanding for the readers.
Response: That is a good point that the coauthors and I have discussed internally. A diagram has been prepared but to constrain the size of the section, it was not added to the paper. Conversely, the text that describes the process was changed to improve readability.
3.All abbreviations used should be included in the nomenclature section.
Response: Abbreviations that were missing from the nomenclature section were appended.
- Methodology section that is section 4 should be made concise and to be restructured for better readability
Response: The section was improved for readability.
- Resolution of Figure 4 needs improvement.
Response: Figure 4’s resolution has been improved. Even higher resolution images are also provided to the journal at submission.
- the entire paper looks as a report rather than a journal paper. drawbacks of the system for nighttime and rainy days, and other shortcomings should be discussed.
Response: The structure and the explanations have been kept rather simple and sometimes overexplained so that researchers and other readers outside the field can fully understand the subject matter. Nighttime and rainy days are both included in the monitored irradiance and the discussion regarding battery systems has been expanded.
- Conclusions should be made concise and can be bullet-pointed rather than explained
Response: A bullet point section was added to the conclusion together with the current explanation.
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper presents energy interactions in a planned residential district in Sweden. It focuses on photovoltaic (PV) systems, district heating and cooling, and heat pumps. The study is well-organized and well-written. However, several revisions are needed to improve the clarity of future versions of the manuscript.
Abstract: The current abstract lists factors (e.g., more balanced use/production of electricity) but does not succinctly state how this study advances prior work. Please specify the quantitative findings (e.g., % improvement in energy efficiency metrics) to strengthen impact.
Introduction: Please expand on the gap in literature. The transition to RES in Nordic climates is mentioned, but the specific challenges (e.g., low solar irradiance and high heating demand) need emphasis. Please clearly state the research questions.
Methodology:
Data Sources: Please justify the use of datasets from Gävle Energy AB. Were these datasets representative of the planned district? Address potential biases (e.g., excluded apartments with zero demand).
Modeling Assumptions: The COP for cooling heat pumps is adapted from a source that advises against simplified methods ([41]). This limitation should be explicitly discussed, and sensitivity analyses suggested.
Also clarify how shading effects were quantified in PVsyst simulations. Were 3D building models used, or were simplifications applied?
Dynamic SCOP: The When2Heat method is well-described, but the validation of its application to DHW heat pumps needs elaboration. Were ground temperatures measured or estimated?
Results:
Energy Performance (EP): The EP results (Table 5) show minor variations (e.g., 64.53 vs. 63.97 kWh/m²). Please discuss whether these differences are statistically or practically significant.
Also explain why no configuration achieved an "A" grade despite PV integration. Is this due to Sweden’s climate, or are there design limitations?
Self-Consumption/Sufficiency: Figure 7 shows self-sufficiency at ~24%. Compare this to benchmarks from similar Nordic studies to contextualize the findings.
Also, the trade-off between self-consumption and system size (Figure 9) is insightful but should be tied to economic viability (e.g., cost of exported electricity vs. storage), if possible.
Please improve the quality of figures and tables in general.
Conclusions: Please answer: what is the potential future development of this study?
Author Response
This paper presents energy interactions in a planned residential district in Sweden. It focuses on photovoltaic (PV) systems, district heating and cooling, and heat pumps. The study is well-organized and well-written. However, several revisions are needed to improve the clarity of future versions of the manuscript.
Abstract: The current abstract lists factors (e.g., more balanced use/production of electricity) but does not succinctly state how this study advances prior work. Please specify the quantitative findings (e.g., % improvement in energy efficiency metrics) to strengthen impact.
Response: The self-sufficiency and self-consumption metrics were added to the abstract when applying the different scenarios. Energy Efficiency metrics were criticized in this context, and their improvement is not the overarching conclusion of the paper.
Introduction: Please expand on the gap in literature. The transition to RES in Nordic climates is mentioned, but the specific challenges (e.g., low solar irradiance and high heating demand) need emphasis. Please clearly state the research questions.
Response: The Aim and Novelty section was modified to include the specific challenges as well as to highlight the unique aspects of the manuscript.
Methodology:
Data Sources: Please justify the use of datasets from Gävle Energy AB. Were these datasets representative of the planned district? Address potential biases (e.g., excluded apartments with zero demand).
Response: Regarding the representativeness of the dataset, a calculation could be added, but the additional complexity would make the paper less clear. A Z-test was considered, but instead, additional text was added to discuss why the datasets were applied and potential biases.
Modeling Assumptions: The COP for cooling heat pumps is adapted from a source that advises against simplified methods ([41]). This limitation should be explicitly discussed, and sensitivity analyses suggested.
Response: This problem is explicitly stated in the paper in the methodology, as well as suggesting the topic for future research. Sensitivity analysis suggestions and expected outcomes have been added to the discussion section.
Also clarify how shading effects were quantified in PVsyst simulations. Were 3D building models used, or were simplifications applied?
Response: That is a methodological step that was overlooked. The question was addressed with new text in the relevant methodology section.
Dynamic SCOP: The When2Heat method is well-described, but the validation of its application to DHW heat pumps needs elaboration. Were ground temperatures measured or estimated?
Response: As the comment suggests, a different source (which is the same used by the When2Heat method) is used in the calculations. A sentence regarding the source of the temperatures and its implications was added to the paper, making this explicit.
Results:
Energy Performance (EP): The EP results (Table 5) show minor variations (e.g., 64.53 vs. 63.97 kWh/m²). Please discuss whether these differences are statistically or practically significant.
Response: Yes, those minor variations are indeed insignificant in the context of assumptions. But the lack of change is a result. A sentence was added to reflect this in the text. The results are presented to show what does and does not affect the EP metric. Fewer decimal points were presented to reflect uncertainty.
Also explain why no configuration achieved an "A" grade despite PV integration. Is this due to Sweden’s climate, or are there design limitations?
Response: That is a good question. Text regarding postulating why the buildings did not achieve the highest grade was added to the relevant section. However, a further analysis of factors that lead to a high grade is beyond the scope of this paper.
Self-Consumption/Sufficiency: Figure 7 shows self-sufficiency at ~24%. Compare this to benchmarks from similar Nordic studies to contextualize the findings.
Response: A comparison of another study and a review paper on the subject has been added to the discussion section.
Also, the trade-off between self-consumption and system size (Figure 9) is insightful but should be tied to economic viability (e.g., cost of exported electricity vs. storage), if possible.
Response: A careful discussion was added to reflect the relationship between solar self-consumption and the pricing scheme of electricity in Sweden, as well as the system size and the scaling capital costs.
Please improve the quality of figures and tables in general.
Response: Thank you for the opportunity to improve the figures and tables. Several improvements were made to the figures and tables and their respective captions and headings.
Conclusions: Please answer: what is the potential future development of this study?
Response: Some future study avenues were already present in the conclusion, but those were reformulated and broken into their own paragraph.
Reviewer 3 Report
Comments and Suggestions for AuthorsIt is recommended that the following comments be evaluated by the authors;
1) There are instances of repetitive phrasing (e.g., “It is shown that…”) which could be varied for better flow. Consider using more active constructions where appropriate.
2) It is recommended to check the article thoroughly by someone whose native language is English.
3) The expression "as in [12]" in the sentence "Datasets of monitored household electricity consumption of existing buildings were applied to estimate the same for the planned buildings as in [12]" is insufficient for proper attribution. In academic writing, it is preferable to name the author(s) when referencing a prior methodological framework, particularly when it plays a central role in the current study.
“...such as ‘Following the methodology of Kayayan et al. [12]’.”
4) Several figures (e.g., Figure 6, Figure 8, Figure 11, Figure 13, and Figure 14) present values with the unit “kWh/h,” which is dimensionally equivalent to kW, but this notation is non-standard and potentially confusing. I suggest revising all such occurrences for consistency and clarity.
5) The Methods section currently includes only a single explicit equation, despite the study involving multiple energy flows, conversions, and performance metrics. I recommend including additional equations where relevant to better support the underlying methodology.
6) Figure 5 should be presented in a more readable manner, as the current version of the figure is very difficult to read.
7) It is written as “Table 5 average EP results (kWh/m2) and in parentheses the corresponding energy efficiency grade.”
It should be “Table 5. Average EP results (kWh/m2) and in parentheses the corresponding energy efficiency grade.
8) All the words "Table" and "Figure" used in the titles should be written in bold.
9) Attention should be paid to the consistent use of subscripts and superscripts throughout the article. It is recommended to thoroughly check and revise the manuscript accordingly.
In Figure 5: kWh/m2
Comments on the Quality of English LanguageThe language is mostly understandable but needs some minor revision.
1) There are instances of repetitive phrasing (e.g., “It is shown that…”) which could be varied for better flow. Consider using more active constructions where appropriate.
2) It is recommended to check the article thoroughly by someone whose native language is English.
Author Response
1) There are instances of repetitive phrasing (e.g., “It is shown that…”) which could be varied for better flow. Consider using more active constructions where appropriate.
Response: Coauthors and I have reread with a focus on repetitive phrases and changed passive constructions to improve the text.
2) It is recommended to check the article thoroughly by someone whose native language is English.
Response: The text was reread with a focus on the language and changes made where relevant.
3) The expression "as in [12]" in the sentence "Datasets of monitored household electricity consumption of existing buildings were applied to estimate the same for the planned buildings as in [12]" is insufficient for proper attribution. In academic writing, it is preferable to name the author(s) when referencing a prior methodological framework, particularly when it plays a central role in the current study.
“...such as ‘Following the methodology of Kayayan et al. [12]’.”
Response: Authors were named when their contributions were part of the methodological framework.
4) Several figures (e.g., Figure 6, Figure 8, Figure 11, Figure 13, and Figure 14) present values with the unit “kWh/h,” which is dimensionally equivalent to kW, but this notation is non-standard and potentially confusing. I suggest revising all such occurrences for consistency and clarity.
Response: kWh/h is dimensionally equivalent to kW. Writing out the redundant hour explicitly communicates that power fluctuations were only analyzed at the hourly scale and not in a higher temporal resolution. For the sake of clarity changed to the standard notation.
5) The Methods section currently includes only a single explicit equation, despite the study involving multiple energy flows, conversions, and performance metrics. I recommend including additional equations where relevant to better support the underlying methodology.
Response: The equations for self-sufficiency and self-consumption were added as presented as indicators. The thermal-mass balance equations were not added since they are explained in the text and are variations of a well-understood analysis technique.
6) Figure 5 should be presented in a more readable manner, as the current version of the figure is very difficult to read.
Response: Figures should be easy to parse. The text size was increased for readability, the attribution text in the map (which is necessary for sharing the map publicly) was reduced to not disturb the image, and the picture caption was rewritten to improve understanding.
7) It is written as “Table 5 average EP results (kWh/m2) and in parentheses the corresponding energy efficiency grade.”
It should be “Table 5. Average EP results (kWh/m2) and in parentheses the corresponding energy efficiency grade.
8) All the words "Table" and "Figure" used in the titles should be written in bold.
Response: The words Table and Figure were bolded in all the headings and captions.
9) Attention should be paid to the consistent use of subscripts and superscripts throughout the article. It is recommended to thoroughly check and revise the manuscript accordingly.
In Figure 5: kWh/m2
Response: We changed to have the correct superscript. Subscripts and superscripts were checked for consistency.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsCompared to the initial draft of this manuscript, the authors have addressed the reviewer's comments.
