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Improvements of U-p...
Improvements of U-pipe Borehole Heat Exchangers
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- Acuña, José, 1982- (författare)
- KTH,Tillämpad termodynamik och kylteknik,Energiteknik
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- Palm, Björn, Professor (preses)
- KTH,Tillämpad termodynamik och kylteknik
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- Gehlin, Signhild, Dr. (opponent)
- EMTF, Luleå Tekniska Universitet
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(creator_code:org_t)
- ISBN 9789174156607
- Stockholm : KTH, 2010
- Engelska 97 s.
- Relaterad länk:
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http://www.energy.kt...
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visa fler...
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https://kth.diva-por... (primary) (Raw object)
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- The sales of Ground Source Heat Pumps in Sweden and many other countries are having a rapid growth in the last decade. Today, there are approximately 360 000 systems installed in Sweden, with a growing rate of about 30 000 installations per year. The most common way to exchange heat with the bedrock in ground source heat pump applications is circulating a secondary fluid through a Borehole Heat Exchanger (BHE), a closed loop in a vertical borehole. The fluid transports the heat from the ground to a certain heating and/or cooling application. A fluid with one degree higher or lower temperature coming out from the borehole may represent a 2-3% change in the COP of a heat pump system. It is therefore of great relevance to design cost effective and easy to install borehole heat exchangers. U-pipe BHEs consisting of two equal cylindrical pipes connected together at the borehole bottom have dominated the market for several years in spite of their relatively poor thermal performance and, still, there exist many uncertainties about how to optimize them. Although more efficient BHEs have been discussed for many years, the introduction of new designs has been practically lacking. However, the interest for innovation within this field is increasing nowadays and more effective methods for injecting or extracting heat into/from the ground (better BHEs) with smaller temperature differences between the heat secondary fluid and the surrounding bedrock must be suggested for introduction into the market.This report presents the analysis of several groundwater filled borehole heat exchangers, including standard and alternative U-pipe configurations (e.g. with spacers, grooves), as well as two coaxial designs. The study embraces measurements of borehole deviation, ground water flow, undisturbed ground temperature profile, secondary fluid and groundwater temperature variations in time, theoretical analyses with a FEM software, Distributed Thermal Response Test (DTRT), and pressure drop. Significant attention is devoted to distributed temperature measurements using optic fiber cables along the BHEs during heat extraction and heat injection from and to the ground.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Naturresursteknik -- Annan naturresursteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Environmental Engineering -- Other Environmental Engineering (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences (hsv//eng)
- TEKNIK OCH TEKNOLOGIER -- Samhällsbyggnadsteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Civil Engineering (hsv//eng)
Nyckelord
- Borehole Heat Exchanger
- Distributed Thermal Response Test
- Ground Source Heat Pumps
- Environmental engineering
- Miljöteknik
- Earth sciences
- Geovetenskap
- Civil engineering and architecture
- Samhällsbyggnadsteknik och arkitektur
Publikations- och innehållstyp
- vet (ämneskategori)
- lic (ämneskategori)
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