A case study of a long-duration thermal response test in borehole heat exchangers

TY - GEN

T1 - A case study of a long-duration thermal response test in borehole heat exchangers

AU - Radioti, Georgia

AU - Cerfontaine, Benjamin

AU - Charlier, Robert

AU - Nguyen, Frederic

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Shallow closed-loop geothermal systems are worldwide applied providing economical and environmental benefits. This paper presents an in-situ study of four Borehole Heat Exchangers of 100 m long, installed in an heterogeneous bedrock in the campus of the University of Liege (Liege, Belgium). A Thermal Response Test (TRT) of a heating phase of 7 months was conducted in one of the boreholes. During this test, temperature was measured at the pipe inlet and outlet, as well as along the four boreholes by the fiber optics. To further investigate the measured data, the test was simulated by 3D numerical modeling. The comparison of the measured data with the numerical results allowed to detect the critical parameters for the behavior of the BHE and for the temperature evolution in the surrounding rock mass. In this case study, the behavior of the BHE could be predicted based on the results of a typical-duration TRT (of a few days), considering the ground an homogenous and isotropic material. However, the thermal plume in the surrounding ground seems to be influenced by several factors, such as the bedrock heterogeneity, the distance to the heating source, air temperature variations and thermal effects at the borehole bottom end.

AB - Shallow closed-loop geothermal systems are worldwide applied providing economical and environmental benefits. This paper presents an in-situ study of four Borehole Heat Exchangers of 100 m long, installed in an heterogeneous bedrock in the campus of the University of Liege (Liege, Belgium). A Thermal Response Test (TRT) of a heating phase of 7 months was conducted in one of the boreholes. During this test, temperature was measured at the pipe inlet and outlet, as well as along the four boreholes by the fiber optics. To further investigate the measured data, the test was simulated by 3D numerical modeling. The comparison of the measured data with the numerical results allowed to detect the critical parameters for the behavior of the BHE and for the temperature evolution in the surrounding rock mass. In this case study, the behavior of the BHE could be predicted based on the results of a typical-duration TRT (of a few days), considering the ground an homogenous and isotropic material. However, the thermal plume in the surrounding ground seems to be influenced by several factors, such as the bedrock heterogeneity, the distance to the heating source, air temperature variations and thermal effects at the borehole bottom end.

KW - Geothermal systems

KW - High-resolution temperature profiles

KW - Numerical modeling

KW - Thermal response test

UR - https://www.scopus.com/pages/publications/85060340657

U2 - 10.1007/978-981-10-6713-6_63

DO - 10.1007/978-981-10-6713-6_63

M3 - Conference contribution

AN - SCOPUS:85060340657

SN - 978-981-10-6712-9

T3 - Lecture Notes in Civil Engineering

SP - 637

EP - 643

BT - Proceedings of the 4th Congrès International de Géotechnique - Ouvrages -Structures

A2 - Tran-Nguyen, Hoang-Hung

A2 - Wong, Henry

A2 - Ragueneau, Frederic

A2 - Ha-Minh, Cuong

PB - Springer Verlag

CY - 978-981-10-6713-6

ER -