Explicit multipole formulas for calculating thermal resistance of single utube ground heat exchangers
(2018) In Energies 11(1). Abstract
Borehole thermal resistance is both an important design parameter and a key performance characteristic of a ground heat exchanger. Another quantity that is particularly important for ground heat exchangers is the internal thermal resistance between the heat exchanger pipes. Both these resistances can be calculated to a high degree of accuracy by means of the wellknown multipole method. However, the multipole method has a fairly intricate mathematical algorithm and is thus not trivial to implement. Consequently, there is considerable interest in developing explicit formulas for calculating borehole resistances. This paper presents derivation and solutions of newly derived secondorder and higherorder multipole formulas for calculating... (More)
Borehole thermal resistance is both an important design parameter and a key performance characteristic of a ground heat exchanger. Another quantity that is particularly important for ground heat exchangers is the internal thermal resistance between the heat exchanger pipes. Both these resistances can be calculated to a high degree of accuracy by means of the wellknown multipole method. However, the multipole method has a fairly intricate mathematical algorithm and is thus not trivial to implement. Consequently, there is considerable interest in developing explicit formulas for calculating borehole resistances. This paper presents derivation and solutions of newly derived secondorder and higherorder multipole formulas for calculating borehole thermal resistance and total internal thermal resistance of single Utube ground heat exchangers. A new and simple form of the firstorder multipole formula is also presented. The accuracy of the presented formulas is established by comparing them to the original multipole method. The superiority of the new higherorder multipole formulas over the existing formulas is also demonstrated.
(Less)
 author
 Claesson, Johan ^{LU} and Javed, Saqib ^{LU}
 organization
 publishing date
 2018
 type
 Contribution to journal
 publication status
 published
 subject
 keywords
 Borehole thermal resistance, Boreholes, Calculation, Ground source heat pump (GSHP) systems, Internal thermal resistance, Multipole method, Secondorder, Thirdorder
 in
 Energies
 volume
 11
 issue
 1
 article number
 en11010214
 publisher
 MDPI AG
 external identifiers

 scopus:85054925820
 ISSN
 19961073
 DOI
 10.3390/en11010214
 language
 English
 LU publication?
 yes
 id
 c0f3b36443114999ac5443792558c693
 date added to LUP
 20181109 09:16:12
 date last changed
 20211006 03:33:18
@article{c0f3b36443114999ac5443792558c693, abstract = {<p>Borehole thermal resistance is both an important design parameter and a key performance characteristic of a ground heat exchanger. Another quantity that is particularly important for ground heat exchangers is the internal thermal resistance between the heat exchanger pipes. Both these resistances can be calculated to a high degree of accuracy by means of the wellknown multipole method. However, the multipole method has a fairly intricate mathematical algorithm and is thus not trivial to implement. Consequently, there is considerable interest in developing explicit formulas for calculating borehole resistances. This paper presents derivation and solutions of newly derived secondorder and higherorder multipole formulas for calculating borehole thermal resistance and total internal thermal resistance of single Utube ground heat exchangers. A new and simple form of the firstorder multipole formula is also presented. The accuracy of the presented formulas is established by comparing them to the original multipole method. The superiority of the new higherorder multipole formulas over the existing formulas is also demonstrated.</p>}, author = {Claesson, Johan and Javed, Saqib}, issn = {19961073}, language = {eng}, number = {1}, publisher = {MDPI AG}, series = {Energies}, title = {Explicit multipole formulas for calculating thermal resistance of single utube ground heat exchangers}, url = {http://dx.doi.org/10.3390/en11010214}, doi = {10.3390/en11010214}, volume = {11}, year = {2018}, }