Quantitative evaluation of improper backfilling in vertical borehole
Vertical ground heat exchanger (GHE) is widely being used to exchange heat into the ground by using the system of ground source heat pump (GSHP). The stability and thermal performance of GHE mainly relate to the grout, the advantages of GHE can be negated if the grout is not backfilled properly. In...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
The Japan Society of Mechanical Engineers
2016-06-01
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| Series: | Journal of Thermal Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jtst/11/1/11_2016jtst00018/_pdf/-char/en |
| _version_ | 1828876733854515200 |
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| author | Shangyuan CHEN Jinfeng MAO |
| author_facet | Shangyuan CHEN Jinfeng MAO |
| author_sort | Shangyuan CHEN |
| collection | DOAJ |
| description | Vertical ground heat exchanger (GHE) is widely being used to exchange heat into the ground by using the system of ground source heat pump (GSHP). The stability and thermal performance of GHE mainly relate to the grout, the advantages of GHE can be negated if the grout is not backfilled properly. In order to study the influence of grout backfilling in a vertical GHE, this study established a 2D steady-state heat conduction model, which simulated 4 cases as follows: (1) fine backfilling, (2) porous backfilling, (3) hole-wall delaminating and (4) pipe-wall delaminating. The thermal resistances inside borehole in 4 cases were estimated by using numerical and analytical methods. It has been observed that improper backfilling generates heat barriers, prolongs the time required for heat transfer and reduces heat exchange capacity. The pipe-wall delaminating greatly increases the thermal resistance and brings the worst impact to a GHE. |
| first_indexed | 2024-12-13T08:26:48Z |
| format | Article |
| id | doaj.art-4bd7342c67e548f0a40d382673e05fec |
| institution | Directory Open Access Journal |
| issn | 1880-5566 |
| language | English |
| last_indexed | 2024-12-13T08:26:48Z |
| publishDate | 2016-06-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Thermal Science and Technology |
| spelling | doaj.art-4bd7342c67e548f0a40d382673e05fec2022-12-21T23:53:52ZengThe Japan Society of Mechanical EngineersJournal of Thermal Science and Technology1880-55662016-06-01111JTST00018JTST0001810.1299/jtst.2016jtst00018jtstQuantitative evaluation of improper backfilling in vertical boreholeShangyuan CHEN0Jinfeng MAO1Institute of Military Environmental Teaching & Research, PLA University of Science & TechnologyInstitute of Military Environmental Teaching & Research, PLA University of Science & TechnologyVertical ground heat exchanger (GHE) is widely being used to exchange heat into the ground by using the system of ground source heat pump (GSHP). The stability and thermal performance of GHE mainly relate to the grout, the advantages of GHE can be negated if the grout is not backfilled properly. In order to study the influence of grout backfilling in a vertical GHE, this study established a 2D steady-state heat conduction model, which simulated 4 cases as follows: (1) fine backfilling, (2) porous backfilling, (3) hole-wall delaminating and (4) pipe-wall delaminating. The thermal resistances inside borehole in 4 cases were estimated by using numerical and analytical methods. It has been observed that improper backfilling generates heat barriers, prolongs the time required for heat transfer and reduces heat exchange capacity. The pipe-wall delaminating greatly increases the thermal resistance and brings the worst impact to a GHE.https://www.jstage.jst.go.jp/article/jtst/11/1/11_2016jtst00018/_pdf/-char/envertical ground heat exchangersimproper backfillingthermal resistanceheat transfer |
| spellingShingle | Shangyuan CHEN Jinfeng MAO Quantitative evaluation of improper backfilling in vertical borehole Journal of Thermal Science and Technology vertical ground heat exchangers improper backfilling thermal resistance heat transfer |
| title | Quantitative evaluation of improper backfilling in vertical borehole |
| title_full | Quantitative evaluation of improper backfilling in vertical borehole |
| title_fullStr | Quantitative evaluation of improper backfilling in vertical borehole |
| title_full_unstemmed | Quantitative evaluation of improper backfilling in vertical borehole |
| title_short | Quantitative evaluation of improper backfilling in vertical borehole |
| title_sort | quantitative evaluation of improper backfilling in vertical borehole |
| topic | vertical ground heat exchangers improper backfilling thermal resistance heat transfer |
| url | https://www.jstage.jst.go.jp/article/jtst/11/1/11_2016jtst00018/_pdf/-char/en |
| work_keys_str_mv | AT shangyuanchen quantitativeevaluationofimproperbackfillinginverticalborehole AT jinfengmao quantitativeevaluationofimproperbackfillinginverticalborehole |