Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields
Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For th...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2015-12-01
|
Series: | Sustainability |
Subjects: | |
Online Access: | http://www.mdpi.com/2071-1050/8/1/35 |
id |
doaj-676c9138197e4fcabdb21cdfa4a2ecdf |
---|---|
record_format |
Article |
spelling |
doaj-676c9138197e4fcabdb21cdfa4a2ecdf2020-11-24T20:51:31ZengMDPI AGSustainability2071-10502015-12-01813510.3390/su8010035su8010035Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger FieldsChaofeng Li0Jinfeng Mao1Zheli Xing2Jin Zhou3Yong Li4Institute of Military Environmental Teaching and Research, PLA University of Science and Technology, Nanjing 210007, ChinaInstitute of Military Environmental Teaching and Research, PLA University of Science and Technology, Nanjing 210007, ChinaInstitute of Military Environmental Teaching and Research, PLA University of Science and Technology, Nanjing 210007, ChinaInstitute of Military Environmental Teaching and Research, PLA University of Science and Technology, Nanjing 210007, ChinaInstitute of Military Environmental Teaching and Research, PLA University of Science and Technology, Nanjing 210007, ChinaIntermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposition principle. The model takes into account the heat transfer along the borehole, thermal interference between BHEs, and the influence of groundwater flow. The accuracy of the model is validated through comparison with an experiment carried out under intermittent operation. The model makes it possible to analyze the geo-temperature restoration performance and its influencing factors, such as BHE spacing, heat flow rate, operation mode, and groundwater flow. The main conclusions of this work are as follows. The heat transfer along the borehole should be considered when analyzing the geo-temperature restoration performance. When the BHE spacing increases, the soil temperature change decreases and the heat recovery improves. Therefore, adequate borehole separation distance is essential in the case of a multiple BHE system with unbalanced load. The presence of groundwater flow is associated with interference between the BHEs, which should not be ignored. In the case of long-term operation, the groundwater flow is beneficial to the geo-temperature recovery process, even for downstream BHEs. Finally, a greater groundwater flux leads to a better geo-temperature recovery.http://www.mdpi.com/2071-1050/8/1/35soil temperature recoveryintermittent operationborehole heat exchanger fieldsinfluence factors |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Chaofeng Li Jinfeng Mao Zheli Xing Jin Zhou Yong Li |
spellingShingle |
Chaofeng Li Jinfeng Mao Zheli Xing Jin Zhou Yong Li Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields Sustainability soil temperature recovery intermittent operation borehole heat exchanger fields influence factors |
author_facet |
Chaofeng Li Jinfeng Mao Zheli Xing Jin Zhou Yong Li |
author_sort |
Chaofeng Li |
title |
Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields |
title_short |
Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields |
title_full |
Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields |
title_fullStr |
Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields |
title_full_unstemmed |
Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields |
title_sort |
analysis of geo-temperature restoration performance under intermittent operation of borehole heat exchanger fields |
publisher |
MDPI AG |
series |
Sustainability |
issn |
2071-1050 |
publishDate |
2015-12-01 |
description |
Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposition principle. The model takes into account the heat transfer along the borehole, thermal interference between BHEs, and the influence of groundwater flow. The accuracy of the model is validated through comparison with an experiment carried out under intermittent operation. The model makes it possible to analyze the geo-temperature restoration performance and its influencing factors, such as BHE spacing, heat flow rate, operation mode, and groundwater flow. The main conclusions of this work are as follows. The heat transfer along the borehole should be considered when analyzing the geo-temperature restoration performance. When the BHE spacing increases, the soil temperature change decreases and the heat recovery improves. Therefore, adequate borehole separation distance is essential in the case of a multiple BHE system with unbalanced load. The presence of groundwater flow is associated with interference between the BHEs, which should not be ignored. In the case of long-term operation, the groundwater flow is beneficial to the geo-temperature recovery process, even for downstream BHEs. Finally, a greater groundwater flux leads to a better geo-temperature recovery. |
topic |
soil temperature recovery intermittent operation borehole heat exchanger fields influence factors |
url |
http://www.mdpi.com/2071-1050/8/1/35 |
work_keys_str_mv |
AT chaofengli analysisofgeotemperaturerestorationperformanceunderintermittentoperationofboreholeheatexchangerfields AT jinfengmao analysisofgeotemperaturerestorationperformanceunderintermittentoperationofboreholeheatexchangerfields AT zhelixing analysisofgeotemperaturerestorationperformanceunderintermittentoperationofboreholeheatexchangerfields AT jinzhou analysisofgeotemperaturerestorationperformanceunderintermittentoperationofboreholeheatexchangerfields AT yongli analysisofgeotemperaturerestorationperformanceunderintermittentoperationofboreholeheatexchangerfields |
_version_ |
1716802016841302016 |