when does a fracture matter for a borehole heat exchanger€¦ · the university of southampton...
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Engineering and the Environment
The University of Southampton
GSHPA technical seminar
Leeds, 24 May 2018
When does
a fracture matter
for a borehole
heat exchanger ?
Sasha PedchenkoFleur LoveridgeNick WoodmanWilliam Powrie
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
460 research papers
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Apparent
thermal
conductivity
dispersivity tensor
heat capacity of fluid
Darcy velocity
(Sauty et al., 1982)
= +Effective
thermal
conductivity ∗∗
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Fracture distance
Fracture aperture
Dehkordi et al., 2015
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Fracture distance
Fracture aperture
Dehkordi et al., 2015
Fracture in impermeablematrix
apparent thermal conductivity
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
fracture influence
groundwater & uncertainty
effective parameters
Concept
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Workflow
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Numerical model
2D
Validation
MILS
One-factor-at-a-time
sensitivity analysis
Uncertainty analysis
30 000 runs
Example
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Distance 0.5 m
after 30 years
2K
Example
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Distance 0.5 m
Distance 10 m
after 30 years
2K
2K
Effects
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
distance 10 m
0.05 m/day in matrix
Effects
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
0.05 m/day in matrix0.005 m/day in matrix
distance 10 m
Groundwater
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
~7 K
Groundwater
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
~100m
Uncertainty
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Uncertainty
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
☺
Uncertainty
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
☺
Sensitivity
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
0.05 m/day in matrix
0.005 m/day in matrix
☺
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Apparent thermal conductivity
Slow local groundwater flow
Slow local groundwater flow
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Apparent thermal conductivity Fast local
groundwater flow
Oleksandra PedchenkoEngineering and the EnvironmentUniversity of Southampton
Thank youQuestions & advice welcome
Q&A supplements
Sensitivity
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
0.05 m/day
0.005 m/day
Uncertainty
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
0.05 m/day in matrix
0.005 m/day in matrix
Intro
Intro Methods Fracture Groundwater Uncertainty Sensitivity Conclusion
Apparent thermal conductivity
𝜆𝑎 = 𝜆𝐴 + 𝛼 𝛾𝐹 𝑣
effectivethermal conductivity of porous medium
dispersivitytensor
heat capacity of fluid
Darcy velocity
(Sauty et al 1982)