An Overview of Sandbox Experiment on Ground Heat Exchangers

Round 1

Reviewer 1 Report

This overview, but I think it will be better to call it a review, is really good prepared. It is really interesting with photos and examples. It is not boring review although it has about 50 pages. The only thing I could pick on is the grouping of citations in introduction, e.g. 42-46 or 51-55. It is better to write at least one sentence about each literary item than to group literature artificially.

Congratulations to the authors, great job 

Author Response

Reply to the comments of reviewer #1:

 

-The only thing I could pick on is the grouping of citations in introduction, e.g. 42-46 or 51-55. It is better to write at least one sentence about each literary item than to group literature artificially.

Thanks for your valuable suggestion. Now We have explained some points which are supported by Ref 39, Ref 40, Ref 41, Ref 44, Ref 45, Ref 46, Ref 54, Ref 55, as follows:

(e.g., numerical simulation^[37-38]by using two model order reduction (MOR) methods^[39], COMSOL environment^[40], FORTRAN language^[41]and analytical calculation^[42-43] by considering thermophysical parameters and temperature distribution^[44], non-uniformity of the ground^[45], temperature response^[46] ) and experiment (e.g., sandbox experiment ^[47-50] field test about energy piles^[51-53] under groundwater flow^[54], equipped with steel pipe heat exchangers^[55]). 

The corrections are highlighted with a yellow background in the revised manuscript for your convenience.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript provides a good overview of sandbox experiment of ground heat exchangers. The authors systematically summarized the work of other researchers by different types of the ground heat exchangers and discussed the existing problems and prospects. Some cited images are not of good quality. Some numbers are difficult to read.  I suggest the authors to replace some images with high resolution, e.g. Fig 3a, 14. In Table 1, the years of horizontal seepage experiments and multi-layer soil experiments are in bold, is there a reason for that?

Author Response

Some cited images are not of good quality. Some numbers are difficult to read.  I suggest the authors to replace some images with high resolution, e.g. Fig 3a, 14.

Thanks for your valuable suggestion. Now We have improved the quality of the Figure 14, as shown in the figure below:

(a) 30 °C heat source

(b) 35 °C heat source

(c) 40 °C heat source

The corrections are highlighted with a yellow background in the revised manuscript for your convenience.

 

-In Table 1, the years of horizontal seepage experiments and multi-layer soil experiments are in bold, is there a reason for that?

Thanks for your valuable suggestion. We have changed these words not bold.

The corrections are highlighted with a yellow background in the revised manuscript for your convenience.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments for author File: Comments.pdf

Abstract:

It needs to have some numbers from the results.

Figure 14. needs to be clearer to read numbers, it may be put in vertically and makes bigger and clearer.

References:

 

It is too much, and needs to be more concentrated for the last 10 years, there are some of it more than 10 years ago.

Author Response

Reply to the comments of reviewer #3:

 

-Abstract: It needs to have some numbers from the results.

Thanks for your valuable suggestion. Now We have added some quantitative results in the abstract, as follows:

It was observed that the heat transfer efficiency of a single spiral tube is only 80% compared to that of a double spiral tube.

It was revealed that the heat transfer distance of a Single U-shaped energy pile in the radial direction is three times greater than in the vertical direction.

The corrections are highlighted with a yellow background in the abstract for your convenience.

 

-Figure 14. needs to be clearer to read numbers, it may be put in vertically and makes bigger and clearer.

Thanks for your valuable suggestion. Now We have placed Figure 14 vertically.

(a) 30 °C heat source

(b) 35 °C heat source

(c) 40 °C heat source

The corrections are highlighted with a yellow background in the revised manuscript for your convenience.

 

-References: It is too much, and needs to be more concentrated for the last 10 years, there are some of it more than 10 years ago.

Thanks for your valuable suggestion. Now We removed some old references and replaced them with Ref 1, Ref 2, Ref 3, Ref 7, Ref 8, Ref 12, Ref 13, Ref 14, Ref 18, Ref 23, Ref 26, Ref 27, Ref 28, Ref 29, Ref 32, Ref 33 published in nearly last decade.

[1]  Pomianowski M, Johra H, Marszal-Pomianowska A, et al. Sustainable and energy-efficient domestic hot water systems: A review. Renewable and Sustainable Energy Reviews, 2020, 128: 109900.

[2]  Wu W, Skye H. Residential net-zero energy buildings: Review and perspective. Renewable and Sustainable Energy Reviews, 2021, 142: 110859.

[3]  Amasyali K, El-Gohary N. A review of data-driven building energy consumption prediction studies. Renewable and Sustainable Energy Reviews, 2018, 81: 1192-1205.

[7]  Mui K, Tsang T, Wong L. Bayesian updates for indoor thermal comfort models. Journal of Building Engineering, 2020, 29: 101117.

[8] Cao X, Dai X, Liu J. Building energy-consumption status worldwide and the state-of-the-art technologies for zero-energy buildings during the past decade. Energy and buildings, 2016, 128: 198-213.

[12] Self S, Reddy B, Rosen M. Geothermal heat pump systems: Status review and comparison with other heating options. Applied energy, 2013, 101: 341-348.

[13] Liang B, Chen M, Orooji Y. Effective parameters on the performance of ground heat exchangers: A review of latest advances. Geothermics, 2022, 98: 102283.

[14] Menegazzo D, Lombardo G, Bobbo S, et al. State of the art, perspective and obstacles of ground-source heat pump technology in the European building sector: A review. Energies, 2022, 15(7): 2685.

[18] Fang L, Diao N, Shao Z, et al. A computationally efficient numerical model for heat transfer simulation of deep borehole heat exchangers[J]. Energy and Buildings, 2018, 167: 79-88.

[23] Gaur A, Fitiwi D, Curtis J. Heat pumps and our low-carbon future: A comprehensive review. Energy Research & Social Science, 2021, 71: 101764.

[26] Aresti L, Christodoulides P, Florides G. A review of the design aspects of ground heat exchangers. Renewable and Sustainable Energy Reviews, 2018, 92: 757-773.

[27] Aranzabal N, Martos J, Steger H, et al. Temperature measurements along a vertical borehole heat exchanger: A method comparison. Renewable Energy, 2019, 143: 1247-1258.

[28] Spitler J, Bernier M. Vertical borehole ground heat exchanger design methods Advances in ground-source heat pump systems. Woodhead Publishing, 2016: 29-61.

[29] Liu X, Spitler J, Qu M, et al. Recent developments in the design of vertical borehole ground heat exchangers for cost reduction and thermal energy storage. Journal of Energy Resources Technology, 2021, 143(10): 100803.

[32] Cunha R, Bourne-Webb P. A critical review on the current knowledge of geothermal energy piles to sustainably climatize buildings. Renewable and Sustainable Energy Reviews, 2022, 158: 112072.

[33] Rotta Loria A, Laloui L. Thermally induced group effects among energy piles. Géotechnique, 2017, 67(5): 374-393.

The corrections are highlighted with a yellow background in the references for your convenience.

Author Response File: Author Response.docx

Reviewer 4 Report

dear Author, 

This paper is supposed to be a literature review of experimental setups to test the thermal behaviour of a ground heat exchanger.

However, 

the paper structure is very difficult to follow and reading the paper is not easy. 

the paper is not an overview for the toic it looks to me as just summerising other peoples research in section without any clarification for the text. 

the language of the paper requires major English revision.

the introduction of the paper the author used to refer to a huge number of papers to cite information which I believe is not genuine. 

instead of discussing the relevant parts of the test scheme and the theory behind that, He/they split the paper to section summarising previous test setup without a discussing how this links to the other parts of the paper. 

this psper requires a extinsive english revision. 

Author Response

Reply to the comments of reviewer #4:

 

-the paper structure is very difficult to follow and reading the paper is not easy.

Thanks for your helpful suggestion. We have made enhancements to the purpose and content of the experiment to improve the overall structure of the article. Moreover, we have refined the presentation of each experimental result by highlighting the main research findings at the beginning and providing comprehensive descriptions thereafter. In order to facilitate your reading, we can see the last reply to the reviewer's opinion.

The supplement is highlighted with a yellow background in section 2, section 3 and section 4 for your convenience.

 

-the paper is not an overview for the toic it looks to me as just summerising other peoples research in section without any clarification for the text. 

Thanks for your helpful suggestion. We have added some general introductions and summaries in each section, which are similar to the links, so we put the specific content in the last reply reviewer's opinion, please see below.

The supplement is highlighted with a yellow background in section 2, section 3 and section 4 for your convenience.

 

-the language of the paper requires major English revision.

Thanks for your helpful suggestion. We have revised the article based on your suggestions. Specifically, we have refined the language, substituted some inappropriate words, and adjusted sentence structures to improve the overall coherence and completeness of the content.

 

-the introduction of the paper the author used to refer to a huge number of papers to cite information which I believe is not genuine. 

Thanks for your valuable suggestion. Now We have explained some points which are supported by Ref 39, Ref 40, Ref 41, Ref 44, Ref 45, Ref 46, Ref 54, Ref 55, as follows:

(e.g., numerical simulation^[37-38]by using two model order reduction (MOR) methods^[39], COMSOL environment^[40], FORTRAN language^[41]and analytical calculation^[42-43] by considering thermophysical parameters and temperature distribution^[44], non-uniformity of the ground^[45], temperature response^[46] ) and experiment (e.g., sandbox experiment ^[47-50] field test about energy piles^[51-53] under groundwater flow^[54], equipped with steel pipe heat exchangers^[55]). 

The corrections are highlighted with a yellow background in the revised manuscript for your convenience.

 

-instead of discussing the relevant parts of the test scheme and the theory behind that, He/they split the paper to section summarising previous test setup without a discussing how this links to the other parts of the paper. 

Thanks for your helpful suggestion. Based on the classification of different experiments in Sections 2 and 3 of the article, we have added how it differs from the previous experiment at the beginning of each introduction, and included summary paragraphs at the end of each section to investigate the connections between these experiments as well as their respective strengths and limitations.

Author Response File: Author Response.docx

Round 2

Reviewer 4 Report

thanks for updating the text and working on the comments provided