Thermo-Economic Analysis of Near-Surface Geothermal Energy Considering Heat and Cold Supply within a Low-Temperature District Heating Network
Round 1
Reviewer 1 Report
Dear Authors,
please consider the aspects listed below that require to be addressed for rising the quality of your paper.
1) The state of the art is actually not focused on the aim of the paper. It requires to be centred on the references mostly connected with the presented work to clearly show the lacks of the current knowledge. In particular, the different approaches for district heating should be classified and commented, highlighting their aspects of strength and weakness. This, in turn, would show the novelty of the proposed research. Moreover, the paper is too long for the contents. Thus, removing the references not directly connected with the scope of the research would increase the readability of the text.
2) The description of the application of the proposed procedure would require a more detailed and clear identification of the possible applications considered. The implications of the choices and their influence on the achieved results should be discussed. At present, these aspects are just briefly mentioned.
3) The simplifications imposed by the modelling presented need to be indicated and discussed.
4) The results obtained require better explanation and physical motivation. Currently, the discussion is limited to a description of the data presented and lacks in detailing the motivations undergoing the achieved results. In particular, for Figures 1, 5, 7, 9, and 11 the discussion is poor. It does not provide to the reader information regarding the motivations of the different behaviours of the applications.
5) In general, a comprehensive explanation on the achieved results should be provided alongside with the discussion of the single tables and graphs.
6) The quality of Figures and tables is not at a journal level. Furthermore, the Guidelines for the Authors should be considered to be compliant with the requirements.
7) The interval of confidence of the results should be indicated. Please, carefully discuss and motivate this aspect.
8) A validation of the results, a comparison to the results obtained by others and an error analysis of the study method should be included in the work.
9) The conclusions section needs to be extended to present the key aspects of the model and the achieved results. In addition, all the statements should be supported by numerical data. A clear identification of the advantages and disadvantages of Horizontal GHE and Vertical GHE is missing while it is a key aspect of the present research.
10) The highlights of the paper should be included.
Kind regards.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I recommend the article presented for publication, I see it as interesting for this type of work, with a good scientific contribution and a topic that is currently at the forefront.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Recommendation: Minor revision needed as noted.
In the manuscript entitled “Thermo-Economic Analysis of Near-Surface Geothermal Energy Under Consideration of Heat and Cold Supply Within a Low-Temperature District Heating Network”, the authors proposed a transient model of a geothermal low-temperature district heating (LTDH) system to simulate the entire energy system. The work performed a holistic simulation of the heating network, consumers and geothermal heat sources. Heat sources (vertical and a horizontal ground heat exchanger) were investigated and evaluated under thermodynamic and economic aspects. The manuscript is well written and I recommend publication after minor revision.
Table 2
The value of “Share of ethylene glycol” is 20. Is it a weight percentage or volume percentage?
Page 5, line 206
The “COP” should be defined before its first usage.
Nomenclature, line 566
The authors need to check if this is correct: tyear = Current time (day)
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Authors,
all the aspects of criticism that were highlighted during the review process were correctly addressed and the text was accordingly modified.
Kind regards.
