Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers
Given that the issue of variations in geometrical parameters of the borehole heat exchanger (BHE) revolves around the phenomenon of thermal resistance, a thorough understanding of these parameters is beneficial in enhancing thermal performance of BHEs. The present study seeks to identify relative ch...
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| Format: | Article |
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MDPI AG
2020-06-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/12/3275 |
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| author | Aminhossein Jahanbin Giovanni Semprini Andrea Natale Impiombato Cesare Biserni Eugenia Rossi di Schio |
| author_facet | Aminhossein Jahanbin Giovanni Semprini Andrea Natale Impiombato Cesare Biserni Eugenia Rossi di Schio |
| author_sort | Aminhossein Jahanbin |
| collection | DOAJ |
| description | Given that the issue of variations in geometrical parameters of the borehole heat exchanger (BHE) revolves around the phenomenon of thermal resistance, a thorough understanding of these parameters is beneficial in enhancing thermal performance of BHEs. The present study seeks to identify relative changes in the thermal performance of double U-tube BHEs triggered by alterations in circuit arrangements, as well as the shank spacing and the borehole length. The thermal performance of double U-tube BHEs with different configurations is comprehensively analyzed through a 3D transient numerical code developed by means of the finite element method. The sensitivity of each circuit configuration in terms of the thermal performance to variations of the borehole length and shank spacing is investigated. The impact of the thermal interference between flowing legs, namely thermal short-circuiting, on parameters affecting the borehole thermal resistance is addressed. Furthermore, the energy exchange characteristics for different circuit configurations are quantified by introducing the thermal effectiveness coefficient. The results indicate that the borehole length is more influential than shank spacing in increasing the discrepancy between thermal performances of different circuit configurations. It is shown that deviation of the averaged-over-the-depth mean fluid temperature from the arithmetic mean of the inlet and outlet temperatures is more critical for lower shank spacings and higher borehole lengths. |
| first_indexed | 2024-03-10T18:54:02Z |
| format | Article |
| id | doaj.art-32b878ae3e1a44f4a154934bfd10731e |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T18:54:02Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-32b878ae3e1a44f4a154934bfd10731e2023-11-20T04:52:51ZengMDPI AGEnergies1996-10732020-06-011312327510.3390/en13123275Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat ExchangersAminhossein Jahanbin0Giovanni Semprini1Andrea Natale Impiombato2Cesare Biserni3Eugenia Rossi di Schio4Department of Industrial Engineering (DIN), Alma Mater Studiorum—University of Bologna, Viale Risorgimento 2, 40136 Bologna, ItalyDepartment of Industrial Engineering (DIN), Alma Mater Studiorum—University of Bologna, Viale Risorgimento 2, 40136 Bologna, ItalyDepartment of Industrial Engineering (DIN), Alma Mater Studiorum—University of Bologna, Viale Risorgimento 2, 40136 Bologna, ItalyDepartment of Industrial Engineering (DIN), Alma Mater Studiorum—University of Bologna, Viale Risorgimento 2, 40136 Bologna, ItalyDepartment of Industrial Engineering (DIN), Alma Mater Studiorum—University of Bologna, Viale Risorgimento 2, 40136 Bologna, ItalyGiven that the issue of variations in geometrical parameters of the borehole heat exchanger (BHE) revolves around the phenomenon of thermal resistance, a thorough understanding of these parameters is beneficial in enhancing thermal performance of BHEs. The present study seeks to identify relative changes in the thermal performance of double U-tube BHEs triggered by alterations in circuit arrangements, as well as the shank spacing and the borehole length. The thermal performance of double U-tube BHEs with different configurations is comprehensively analyzed through a 3D transient numerical code developed by means of the finite element method. The sensitivity of each circuit configuration in terms of the thermal performance to variations of the borehole length and shank spacing is investigated. The impact of the thermal interference between flowing legs, namely thermal short-circuiting, on parameters affecting the borehole thermal resistance is addressed. Furthermore, the energy exchange characteristics for different circuit configurations are quantified by introducing the thermal effectiveness coefficient. The results indicate that the borehole length is more influential than shank spacing in increasing the discrepancy between thermal performances of different circuit configurations. It is shown that deviation of the averaged-over-the-depth mean fluid temperature from the arithmetic mean of the inlet and outlet temperatures is more critical for lower shank spacings and higher borehole lengths.https://www.mdpi.com/1996-1073/13/12/3275geothermal energyground-source heat pumpsborehole heat exchangersground heat exchangersdouble U-tubecircuit arrangement |
| spellingShingle | Aminhossein Jahanbin Giovanni Semprini Andrea Natale Impiombato Cesare Biserni Eugenia Rossi di Schio Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers Energies geothermal energy ground-source heat pumps borehole heat exchangers ground heat exchangers double U-tube circuit arrangement |
| title | Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers |
| title_full | Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers |
| title_fullStr | Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers |
| title_full_unstemmed | Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers |
| title_short | Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers |
| title_sort | effects of the circuit arrangement on the thermal performance of double u tube ground heat exchangers |
| topic | geothermal energy ground-source heat pumps borehole heat exchangers ground heat exchangers double U-tube circuit arrangement |
| url | https://www.mdpi.com/1996-1073/13/12/3275 |
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