Data-Center Farming: Exploring the Potential of Industrial Symbiosis in a Subarctic Region
, Mattias Vesterlund 3, Andreas Johansson 4 and Marcus Sandberg 1,*
Round 1
Reviewer 1 Report
The presented article is a socio-technical study aimed at assessing the possibility and feasibility of using heat removed from data centers for heating greenhouses. The direction of the study is very relevant, since the digitalization of society and the economy dictates the requirements for the constant increase in the capacity of data centers, and the course towards sustainable and environmentally friendly development of mankind directs towards the rational and conscious use of all resources. The topic of the article will be of interest to specialists and researchers in the fields of agriculture, sustainable development, sociology and information technology. The article has already been completed at a fairly high level, but as some remarks to strengthen its content, several not so critical points can be noted:
1. Due to what sources is the power supply of the data centers under consideration and planned for use - most likely the prevalence of wind turbines? Is it possible to use frost-resistant solar PV modules with an extended service life for power supply of data centers and greenhouses (for example, DOI: 10.4018/IJEOE.2020040106 doi:10.1088/1755-1315/317/1/012002)? During a global transition, such an energy supply will be relevant - perhaps it is worth adding a mention in the literature review.
2. The authors should indicate more clearly the technical risks in the operation of such a system and the methods of their leveling, since data centers are very responsible and demanding systems in terms of the parameters of the environment of the equipment.
3. What is the estimated cost of a system that ensures air movement and control of its parameters - in how many years will it pay off?
4. Is it planned to introduce the results obtained to compare the experimental values ​​with the calculated ones - at which facility?
5. Is it possible to use natural gas/biogas or hydrogen for heating greenhouses? It is interesting to compare them with peat in the table on the level of carbon dioxide emissions. This energy transition is very relevant due to global trends.
6. A reference to figure 6 should be made with a figure (see Figure "6") and the description of the figure should be transferred before the figure itself. Table 2 is not referenced in the text.
7. Is the calculation method proposed by the authors applicable to mining equipment, which is now also popular - perhaps the authors will touch upon this topic in future studies - in the presented work, a little attention can be paid to this issue as well.
8. At the end of the article, the authors should add the separate section "Directions for further research", where they more clearly and openly indicate their plans for the further development of the topic under consideration and the implementation of the results.
In general, the presented article leaves a positive impression, and after taking into account these recommendations, it can be recommended for publication in the journal Sustainability.
Author Response
Our response is attached as a file.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper has improved and seems adequate now.
Author Response
Our response is attached as a file.
Author Response File: Author Response.docx
Reviewer 3 Report
I am honoured to have read this article.
The following additions are needed for improvement:
Chapter 2.1: Clarify the criteria used to invite stakeholders to workshops and interviews - why certain stakeholders were selected as most relevant. The workshop and interview protocol should also be described - what activities were carried out, how many questions were asked in the interview - it should also be explained what type of interview it was - standardised, non-standardised. After the review, I suggest that the authors take a look at this research: https://hrcak.srce.hr/file/307136/
Chapter Conclusion: it only presents a classic type of conclusion, but does not give a future view based on the research conducted - so it is necessary to add how the research will contribute to the profession and how to the authors' future work in this field.
Author Response
Our response is attached as a file.
Author Response File: Author Response.docx
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Considering the core objective of the journal, I don't find the novelty and reliability of the work are adequately justified and described. The manuscript is not well written in terms of detailed methodology, critical analysis, and comparison with present literature/other findings. As a result, in the current form, the paper is not suitable for publication in Sustainability.
1) There is no link between the conducted study and Covid-19. The studied issues were important before the pandemic. The manuscript can do without pandemic excuses.
2) The organization of the manuscript makes it difficult to read.
3) What is the reason for introducing the virtual reality model? It doesn't seem to convey any findings.
4) The heat pump model is based on [36]. Do the authors provide any new contributions?
5) No experimental work to verify the numerical results. How the proposed heat pump model was validated?
6) The optimization section is not clear. Addressing more details in the next publication is not a justification.
Reviewer 2 Report
Please find attached reviewer comments.
Comments for author File: 
Comments.pdf
Reviewer 3 Report
This paper deals with Data center-farming: Industrial symbiosis for post-pandemic cities in subartic climates. The subject of the manuscript falls within the scope of the journal Sustainability. The abstract and keywords are proper although some adjustments seem to be required. Figures and Tables are proper with clear captions, but some improvements in the contents and organization are desirable, as they do not convey solid information sometimes. The organization of the article can be improved, and its structure has to undergo modifications to better deploy the study and presents its relevance, which is not clearly determined. References are recent, but they need to be improved in quantity, as they do not support the findings in a certain way.
Broad points to be addressed are:
- Novelty must be presented more clearly, highlighted, and academic and professional applications need to be indicated;
- The structure of the paper should be revised in a way that the research developed and its presentation can be clear and smooth. A classic method format is recommended;
- The paper does not present a clear method. A general framework or a flowchart presenting the general steps of the study is highly necessary. A better description of the method employed and the whole methodology used in the paper is recommended;
- Further discussion of the results needs improvement. Proper geographical distribution of the references will broaden the study and allow it to be compared and extended to other places;
- The discussion part could reference the hypotheses and assumptions, which are missing;
- The study performed and the validation method need clarification as the paper is somehow difficult to follow;
- Conclusions need to be highlighted and clarified.
Detailed points to be addressed:
-An Instruments Section is recommended to be explained in the paper.
- The figure explaining the scenarios considered needs to be clarified and referenced in Methods section.
- Correct the words “desalination”- and “biomass-” in line 62 and 63.
- Name the authors for reference [32] in line 160
Reviewer 4 Report
- I do not judge about this paper. It is not a formal format of conventional Journal.
- Also I do not know why interview and workshop are described in scientific journal paper.
- please list and define your symbols in nomenclature.
- Please indicate your equations in numbers.
- In each equations, I doubt what the equations means. In your equations, airflow is multiplied by mass flow. What this means? This is not energy flow.
- Symbols in equations are not usual.
- Please explain your calculation logic to obtain your results presented in paper.
- Conclusion (discussion) should be summarized based on your results.
- I doubt whether Figure 5, 6, 7 are experimental results or not. It is not clear.
- I understood that your idea is based on heat exchanging model between GH and DC based on climate conditions. Then means that you should describe your model to connect the calculation model.
- Your presentation and explanation is so vague. Please present your model clearly.
