Nanotechnology Applications in Ground Heat Exchanger Pipes: A Review

Round 1

Reviewer 1 Report

Dear Authors,

 

A very interesting approach regarding the use of nanomaterials and nano-fluids for the GHEs.

I would propose to consider changing the title to better describe your review. (See suggestion within the attached file).

The literature review is well organised presenting in detail several theoretical and numerical studies on HEP using nanofluids and nanomaterials. However, the review's results are being stated mainly as percentages rather than actual numbers. this would have added more value to your work. I understand it is difficult to obtain actual figures, but please do so, where is possible.

A relation between cost and efficiency has been mentioned in terms of implementing and improving the heat transfer which is very positive in GSHP systems.

The conclusion chapter should be further developed once you are mainly referring to your future steps instead of concluding your thorough review.

 Please have a native speaker brush up on your manuscript to eliminate some grammar errors.

You will also find highlighted some more suggestions within the attached manuscript.

 

Comments for author File: Comments.pdf

Author Response

The reply of the reviewer 1 is attached in a PDF file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The topic of the manuscript is a review of scientific articles on nanotechnology trends for heat exchanger pipes for ground source heat pumps. The authors focused on two important elements related to heat exchange: composition of the working liquids and pipe materials of the ground heat exchanger. The overview of the articles for each topic there is divided into two groups: theoretical and numerical simulations and experimental works.

The authors selected about fifty the most characteristic and well-known articles in the field of GHEP nanomaterials and nanoliquids, which were briefly discussed. At the end of the chapters, tables were created that present the types of nanoliquids or nanomaterials, as well as the applications and results that were the subject of these articles. The articles in question appeared in the last 20 years, but most of them are from the last 10 years.

In the "Conclusions", the authors prepared another two tables. In Table 5, the references are assigned to the given parameters of nanomaterials and nanoliquids within the discussed articles. The second one (Table 6.) assigned the type of theoretical-computational or experimental article discussed in the manuscript to the molecular material that was the subject of the discussed article.

The overview is valuable work as it provides a structural and supportive contribution to the field of ground source heat pumps and also presents the current state of the art in the field.

Author Response

The reply of the reviewer 2 is attached in a PDF file.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper presents the analysis and summarizes of theoretical, numerical, and experimental studies of the solutions implemented to improve heat transfer in a GSHP systems using nanotechnology. The subject is interesting and the review can be helpful to the researchers. However, the English of the text needs major modifications and needed to be polished. Some of the examples are mentioned in the following. Also, there are some other questions and modifications that are needed to be answered or implemented which are also mentioned in below:

• In lines 139-140, in sentence “The results show indicated that when the fluid is static”, what do you mean by “The results show” ?
• In lines 190-191, please delete this sentence “All information was reviewed and summarized in tables.” This is not an important result or achievement of the mentioned reference to report.
• In lines 201-202, in sentence “Similarly, the paper [20] summarizes works with the use of suspended nanoparticles to enhancement the heat transfer”, please replace the word “enhancement” with the word “enhance”.
• In lines 208-210, the sentence “A preliminary evaluation of the potential of nanofluids as heat carrier (based on the mathematical model developed by [21]) that asses the vertical temperature of heat carrier in the borehole was performed in [22].” is not clear and meaningful. Please rephrase this sentence.
• In line 218, please replace the word “lenght” with “length”.
• I suggest to add one column to tables 1 and 3 mentioning the model or methods used for the theoretical or the numerical studies.
• Also, for sections 2.1.1 and 2.2.1 explaining a bit about the theory and the main equations used for the theoretical parts will be helpful.
• A few numbers of articles are surveyed in section 2.1.2. Could you explain the reason? Also, the references used for this section are rather old. Please add some references from more recent years meaning 2019-2022.
• In line 567, please replace the phrase “This review aim” with either “The aim of this review” or “This review’s aim”.
• In line 577, please replace the phrase “have a aim” with “have an aim”.

Author Response

The reply of the reviewer 3 is attached in a PDF file.

Author Response File: Author Response.pdf

Reviewer 4 Report

Report

 

      This is a review for the Manuscript Number: applsci-1644760 "Nanotechnology Trends for Ground Heat Exchanger Pipes "

 

   In this paper the authors used of Ground Source Heat Pumps (GSHP) systems has exponentially grown around  the world during the last decades. GSHP offers important benefits such as a cheaper system than direct electric heating systems and oil boilers; they demand for lower power consumption and  require less maintenance than combustion-based heating systems. Moreover, CO2 emissions by  GSHP are lower than other systems such as those based on burning oil, gas, or biomass. However, the principal obstacle for the massive use of GSHP is the high cost of Ground Heat Exchanger  (GHE) installation and low thermodynamic efficiencies. Over the past decade, research has been  conducted to improve heat transfer in GHE pipes using traditional working fluids, developing new  pipe materials, or designing new heat exchanger configurations. This paper summarizes outcomes  of theoretical, numerical and experimental studies on the heat transfer improvement in the GHEP using nanotechnology. The authors development of new fluids (nanofluids) and new materials (nanoparticles  and nanocomposites) applied to heat exchanger pipes, up to designs and configurations of GHEP is  analyzed. As a result, the authors present review renders a perspective for future research regarding the use of nanotechnology to reduce the costs involved in GHEP for GSHP improvement.

 

Comments and Suggestions for Authors:

   The topic of this paper is interesting, and the results seem to be correct and interesting. Therefore, it can be published subject to the following minor modifications:

1. 1. The original papers should be much better presented.
2. 2. The abstract should be improved by mentioning the major contributions.
3. 3. English is good but should be checked for some grammar.
4. 4. What is the novelty of the proposed work? Please list the motivation and contribution in the introduction section.
5. 5. It takes into account the formulation and writing the abbreviations in a more coordinated manner
6. I suggest clarifying the comparison between the new work used and the previous methods
7. 7. As this paper “Nanotechnology Trends for Ground Heat Exchanger Pipes’’ can be interesting for the researchers in many field of applied mathematics. So, the authors can improve the introduction by the recent developments in this field. Also, the reference section can strengthen by including some of the following papers

1- Numerical Simulation of Heat Mass Transfer Effects on MHD Flow of Williamson Nanofluid by a Stretching Surface with Thermal Conductivity and Variable Thickness, Coatings, 2021, 11, 684, 1-20.

2- Evaluating the Unsteady Casson nanofluid Over a Stretching Sheet with Solar Thermal Radiation: An Optimal Case Study, Case Studies in Thermal Engineering , 26, 2021, 101160, 1-15.

3- Galerkin Finite Element Analysis of Magneto Two-Phase Nanofluid Flowing in Double Wavy Enclosure Comprehending an Adiabatic Rotating Cylinder, Scientific Reports, 2021, 11:16494, 1-15.

4- Irreversibility process characteristics of variant viscosity and conductivity on hybrid nanofluid flow through Poiseuille microchannel: A special case study, Case Studies in Thermal Engineering, 27, 2021, 101337,1-12.

Recommendation: After my careful reading, the topic discussed is novel, interesting, significant and important for the related areas. Scientific sound and the problems in the paper is solved in a successful way. Therefore, I recommend the publication of this paper in '' Applied Sciences journal  " after these minor modifications. So, I want to read the revised version of paper after publishing.

With many thanks and best regards.

Comments for author File: Comments.pdf

Author Response

The reply of the reviewer 4 is attached in a PDF file.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Dear Editor,
The paper is properly modified compared to its previous version. I have no further comments and I suggest the paper for publication.