Explicit multipole formulas and thermal network models for calculating thermal resistances of double U-pipe borehole heat exchangers
(2019) In Science and Technology for the Built Environment 25(8). p.980-992- Abstract
Double U-pipe boreholes are the second most used type of ground heat exchangers after single U-pipe boreholes. The borehole thermal resistance is a key design and performance parameter for the double U-pipe boreholes. Another parameter that is particularly important for double U-pipe boreholes is the internal thermal resistance between the U-pipes. There is, however, a general lack of methods that can be used to calculate the thermal resistances of the double U-pipe boreholes. This article presents explicit multipole formulas for calculating thermal resistances of double U-pipe boreholes with symmetrically positioned pipes. The presented formulas include zeroth- and first-order expressions for the borehole thermal resistance and the... (More)
Double U-pipe boreholes are the second most used type of ground heat exchangers after single U-pipe boreholes. The borehole thermal resistance is a key design and performance parameter for the double U-pipe boreholes. Another parameter that is particularly important for double U-pipe boreholes is the internal thermal resistance between the U-pipes. There is, however, a general lack of methods that can be used to calculate the thermal resistances of the double U-pipe boreholes. This article presents explicit multipole formulas for calculating thermal resistances of double U-pipe boreholes with symmetrically positioned pipes. The presented formulas include zeroth- and first-order expressions for the borehole thermal resistance and the internal thermal resistance. The internal thermal resistance formulas cover various possible flow configurations of the heat carrier fluid in the double U-pipes. The accuracy of the presented zeroth- and first-order formulas is established by comparing them to the original 10th-order multipole method. The article also presents thermal network models for computing effective borehole thermal resistance of double U-pipe boreholes from the multipole resistances. Formulas for calculating effective borehole thermal resistance of double U-pipe boreholes are presented for two idealized cases of uniform heat flux and uniform average wall temperature along the borehole.
(Less)
- author
- Claesson, Johan LU and Javed, Saqib LU
- organization
- publishing date
- 2019
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Science and Technology for the Built Environment
- volume
- 25
- issue
- 8
- pages
- 13 pages
- publisher
- Taylor & Francis
- external identifiers
-
- scopus:85073575586
- ISSN
- 2374-4731
- DOI
- 10.1080/23744731.2019.1620565
- language
- English
- LU publication?
- yes
- id
- 882f032e-7864-412d-aa58-04de0ff0b726
- date added to LUP
- 2019-10-29 09:54:14
- date last changed
- 2025-04-04 14:40:56
@article{882f032e-7864-412d-aa58-04de0ff0b726,
abstract = {{<p>Double U-pipe boreholes are the second most used type of ground heat exchangers after single U-pipe boreholes. The borehole thermal resistance is a key design and performance parameter for the double U-pipe boreholes. Another parameter that is particularly important for double U-pipe boreholes is the internal thermal resistance between the U-pipes. There is, however, a general lack of methods that can be used to calculate the thermal resistances of the double U-pipe boreholes. This article presents explicit multipole formulas for calculating thermal resistances of double U-pipe boreholes with symmetrically positioned pipes. The presented formulas include zeroth- and first-order expressions for the borehole thermal resistance and the internal thermal resistance. The internal thermal resistance formulas cover various possible flow configurations of the heat carrier fluid in the double U-pipes. The accuracy of the presented zeroth- and first-order formulas is established by comparing them to the original 10th-order multipole method. The article also presents thermal network models for computing effective borehole thermal resistance of double U-pipe boreholes from the multipole resistances. Formulas for calculating effective borehole thermal resistance of double U-pipe boreholes are presented for two idealized cases of uniform heat flux and uniform average wall temperature along the borehole.</p>}},
author = {{Claesson, Johan and Javed, Saqib}},
issn = {{2374-4731}},
language = {{eng}},
number = {{8}},
pages = {{980--992}},
publisher = {{Taylor & Francis}},
series = {{Science and Technology for the Built Environment}},
title = {{Explicit multipole formulas and thermal network models for calculating thermal resistances of double U-pipe borehole heat exchangers}},
url = {{http://dx.doi.org/10.1080/23744731.2019.1620565}},
doi = {{10.1080/23744731.2019.1620565}},
volume = {{25}},
year = {{2019}},
}