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Effect of groundwater forced seepage on heat transfer characteristics of borehole heat exchangers
Qian Jiang
School of Energy Safety Engineering, Tianjin Chengjian University, Tianjin, China
Corresponding Author
ORCiD: https://orcid.org/0000-0001-8955-5499
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A borehole heat exchangers (BHEs) combined with pumping-injection well is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of the BHEs. According to the three-dimensional unsteady state heat transfer model in aquifer, we derive the convection-dispersion analytical solution of excess temperature in aquifer that considers groundwater forced seepage and thermal dispersion effects in aquifer and the axial effect of the BHEs. Then, we use dimensional analysis method and similarity criteria to build a controllable forced seepage sandbox. The theoretical analysis is combined with the indoor experiment test to verify the correctness and accuracy of the numerical simulation software FEFLOW7.1. On this basis, we perform the numerical simulation calculation to explore the effects of different pumping-injection flow volume on the Darcy flow velocity of the aquifer where the BHEs are located, the average heat transfer efficiency and the heat transfer rates per unit borehole depth of the BHEs. The results show that when the pumping flow volume is increased from 200 m3∙d-1 to 1200 m3∙d-1, the Darcy velocity correspondingly increases to about 10 times the previous velocity. The average heat efficiency coefficient of the BHEs increases by 11.5% in cooling stage, and by 7.5% in heating stage. When the pumping-injection flow volume is 400~600 m3∙d-1, the increment of heat transfer rates per unit borehole depth of the BHEs reaches 12.8~17.9 W∙m-1 and 3.6~4.2 W∙m-1 during the cooling stage and heating stage respectively, and then decreases as the flow volume increases gradually.
Keywords
borehole heat exchangers, groundwater forced seepage, analytical solution, laboratory experiment, numerical simulation calculation, pumping-injection well
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CURRENT STATUS: Under Review
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Posted 01 Feb, 2021
Editorial decision: Minor revision
On 01 Feb, 2021
Review #1 received
Received 28 Jan, 2021
Reviewer #1 agreed
On 24 Jan, 2021
Reviewers invited
Invitations sent on 23 Jan, 2021
Editor assigned
On 21 Jan, 2021
Submission checks complete
On 21 Jan, 2021
Editor invited
On 21 Jan, 2021
First submitted
On 21 Jan, 2021
This version was not preprinted
No community comments so far
Editor assigned
On 21 Jan, 2021
Submission checks complete
On 21 Jan, 2021
Editor invited
On 21 Jan, 2021
Version 2
Posted 11 Dec, 2020
No comments provided
Editorial decision: Minor revision
On 03 Jan, 2021
Editor assigned
On 01 Dec, 2020
Submission checks complete
On 01 Dec, 2020
Editor invited
On 01 Dec, 2020
No comments provided
Editorial decision: Major revision
On 26 Oct, 2020
Review #2 received
Received 22 Oct, 2020
Review #1 received
Received 25 Sep, 2020
Reviewer #2 agreed
On 21 Sep, 2020
Reviewers invited
Invitations sent on 17 Sep, 2020
Reviewer #1 agreed
On 17 Sep, 2020
Editor assigned
On 03 Aug, 2020
Submission checks complete
On 02 Aug, 2020
Editor invited
On 02 Aug, 2020
First submitted
On 01 Aug, 2020
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Subject Areas
Food Science & Technology
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This preprint is under consideration at Geothermal Energy. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Effect of groundwater forced seepage on heat transfer characteristics of borehole heat exchangers
Qian Jiang
School of Energy Safety Engineering, Tianjin Chengjian University, Tianjin, China
Corresponding Author
ORCiD: https://orcid.org/0000-0001-8955-5499
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version (no preprint)
Posted 01 Feb, 2021
Editorial decision: Minor revision
On 01 Feb, 2021
Review #1 received
Received 28 Jan, 2021
Reviewer #1 agreed
On 24 Jan, 2021
Reviewers invited
Invitations sent on 23 Jan, 2021
Editor assigned
On 21 Jan, 2021
Submission checks complete
On 21 Jan, 2021
Editor invited
On 21 Jan, 2021
First submitted
On 21 Jan, 2021
This version was not preprinted
No community comments so far
Editor assigned
On 21 Jan, 2021
Submission checks complete
On 21 Jan, 2021
Editor invited
On 21 Jan, 2021
Version 2
Posted 11 Dec, 2020
No comments provided
Editorial decision: Minor revision
On 03 Jan, 2021
Editor assigned
On 01 Dec, 2020
Submission checks complete
On 01 Dec, 2020
Editor invited
On 01 Dec, 2020
No comments provided
Editorial decision: Major revision
On 26 Oct, 2020
Review #2 received
Received 22 Oct, 2020
Review #1 received
Received 25 Sep, 2020
Reviewer #2 agreed
On 21 Sep, 2020
Reviewers invited
Invitations sent on 17 Sep, 2020
Reviewer #1 agreed
On 17 Sep, 2020
Editor assigned
On 03 Aug, 2020
Submission checks complete
On 02 Aug, 2020
Editor invited
On 02 Aug, 2020
First submitted
On 01 Aug, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Food Science & Technology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
The most recent version of this article is available here.
A borehole heat exchangers (BHEs) combined with pumping-injection well is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of the BHEs. According to the three-dimensional unsteady state heat transfer model in aquifer, we derive the convection-dispersion analytical solution of excess temperature in aquifer that considers groundwater forced seepage and thermal dispersion effects in aquifer and the axial effect of the BHEs. Then, we use dimensional analysis method and similarity criteria to build a controllable forced seepage sandbox. The theoretical analysis is combined with the indoor experiment test to verify the correctness and accuracy of the numerical simulation software FEFLOW7.1. On this basis, we perform the numerical simulation calculation to explore the effects of different pumping-injection flow volume on the Darcy flow velocity of the aquifer where the BHEs are located, the average heat transfer efficiency and the heat transfer rates per unit borehole depth of the BHEs. The results show that when the pumping flow volume is increased from 200 m3∙d-1 to 1200 m3∙d-1, the Darcy velocity correspondingly increases to about 10 times the previous velocity. The average heat efficiency coefficient of the BHEs increases by 11.5% in cooling stage, and by 7.5% in heating stage. When the pumping-injection flow volume is 400~600 m3∙d-1, the increment of heat transfer rates per unit borehole depth of the BHEs reaches 12.8~17.9 W∙m-1 and 3.6~4.2 W∙m-1 during the cooling stage and heating stage respectively, and then decreases as the flow volume increases gradually.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.