Design and Monitoring of borehole heat exchangers using distributed temperature measurements KTH Royal Institute of Technology José Acuña
Design and Monitoring of borehole heat exchangers using distributed
temperature measurements
KTH Royal Institute of TechnologyJosé Acuña
www.svepinfo.sewww.pemtec.se
Fiber inne i borrhålen
TnTn‐1
T1 T2 T3 T4 ……….
Distributed Temperature Sensing
DTS Instrument
DTS Instrument
Measurement example: U-pipe BHEs
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9 11 13 15 17 19 21 23 25
Djup
[m]
Temperatur [C]
0,5 l/s0,4 l/s0,2 l/s0,14 l/s
Dep
th[m
]
time[°C] 0
260
Measurement example: DTRT
Example of results from DTRT
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2.5 3 3.5Djup
[m]
λberg [W/mK]
‐250
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‐50
03 3,2 3,4 3,6 3,8 4
Djup [m]
Värmelednings förmåga [ W/mK]
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9.0 11.0 13.0 15.0 17.0 19.0
Dju
p [
m]
Temperatur [°C]
Stockholms University
130 boreholes230 m deep
Winter: 1400 kW2,5 / 6,0 ºC
Summer: 2500 kW31 / 25 ºC
Hesselmannskastiftelsen
How to include DTS in design and monitoring of large bore fields ?
Installationsite
Optical fiber cables outside the BHE pipes
Some g-functions in zone 12
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‐11 ‐9 ‐7 ‐5 ‐3 ‐1 1 3 5
g‐functio
n
ln (9FoH)
Single borehole
Two boreholes
Manifold 12
Whole Installation
Theory and practice
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9 11 13 15 17 19 21 23 25
Djup
[m]
Temperatur [C]
0,5 l/s0,4 l/s0,2 l/s0,14 l/s
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150
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300
9.0 11.0 13.0 15.0 17.0 19.0
Dju
p [
m]
Temperatur [°C]
Measured data vs.models byPatricia Monzóand Alberto Lazzarotto
First DTRT: Frescati
Preliminary results
KTH team: FRESCATI PROJECT
KTH energiteknikKTH byggnadsteknik
KTHs team:Patricia Monzó, doktorandDavide Rolando, researcherAlberto Lazarotto, doktorand (PhD tomorrow !!)José Acuña, researcherProf. Björn PalmProf. Folke Björk
An example from USA
Borehole Thermal Energy Storage (BTES)
• Albany, GA• BTES• 306 boreholes• About 64 m deep
DTS at the BTES
DTS
X
X
Monitoring borehole, splice box
First DTS measurement (raw data)
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Tempe
rature [ºC]
Signal strength
Measured length [m]
Stokes
anti‐Stokes
temperature (°C)
DTRT0
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19 24 29 34 39 44
Depth [m
]
Temperature [ºC]
A DTRT has been recentlycarried out in order to get a better insight about the geology
TACK!
Contact:
José Acuña, PhDKTH Royal Institute of Technology, Sweden
Mob: 076 232 00 08Email: [email protected]
www.energy.kth.se/energibrunnar