First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger
Abstract Here, we present the first application of a temperature sensor module (TSM) for deducing groundwater flow velocity and direction at borehole heat exchangers (BHEs). The TSM maps the horizontal temperature distribution around a BHE. As groundwater flow distorts this temperature distribution,...
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Online Access: | https://doi.org/10.1186/s40517-019-0152-5 |
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doaj-ab0f7216bd014915a90297c4f158bef92020-12-13T12:20:51ZengSpringerOpenGeothermal Energy2195-97062019-12-017111610.1186/s40517-019-0152-5First field application of temperature sensor modules for groundwater flow detection near borehole heat exchangerAlexander Michalski0Norbert Klitzsch1Applied Geophysics and Geothermal Energy, E.ON ERC, RWTH Aachen UniversityApplied Geophysics and Geothermal Energy, E.ON ERC, RWTH Aachen UniversityAbstract Here, we present the first application of a temperature sensor module (TSM) for deducing groundwater flow velocity and direction at borehole heat exchangers (BHEs). The TSM maps the horizontal temperature distribution around a BHE. As groundwater flow distorts this temperature distribution, flow velocity and direction can be inferred from the measured temperatures. As modular systems, TSMs can be attached to a BHE at any depth. For the studied BHE, the depths of interest are 82 m and at 94 m. We recorded TSM data for 2 weeks before and during the operation of the BHE. After simulating the working fluid temperature, we model the horizontal temperature distributions using the working fluid temperatures at the depths of interest as input. We use the latter simulations for inferring groundwater flow by minimizing the root mean square error between the measured and simulated temperatures. We obtain a groundwater flow of 0.4 m/day in the NW direction and groundwater flow below the detection limit of 0.01 m to 0.02 m/day at 82 m and 94 m depths, respectively. A flow meter measurement in a nearby groundwater well confirms the flow direction at 82 m but gives an order of magnitude higher velocity, which we attribute to the measurement principle. Moreover, long-term monitoring of a BHE equipped with multiple TSMs could provide information on seasonal variations in groundwater flow, changes in the thermal properties of the BHE filling or changes in the thermal resistance between BHE and ground.https://doi.org/10.1186/s40517-019-0152-5Borehole heat exchangerBHEGroundwater flowAdvective heat transportEnhanced geothermal response testTemperature sensor module |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Alexander Michalski Norbert Klitzsch |
spellingShingle |
Alexander Michalski Norbert Klitzsch First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger Geothermal Energy Borehole heat exchanger BHE Groundwater flow Advective heat transport Enhanced geothermal response test Temperature sensor module |
author_facet |
Alexander Michalski Norbert Klitzsch |
author_sort |
Alexander Michalski |
title |
First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
title_short |
First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
title_full |
First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
title_fullStr |
First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
title_full_unstemmed |
First field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
title_sort |
first field application of temperature sensor modules for groundwater flow detection near borehole heat exchanger |
publisher |
SpringerOpen |
series |
Geothermal Energy |
issn |
2195-9706 |
publishDate |
2019-12-01 |
description |
Abstract Here, we present the first application of a temperature sensor module (TSM) for deducing groundwater flow velocity and direction at borehole heat exchangers (BHEs). The TSM maps the horizontal temperature distribution around a BHE. As groundwater flow distorts this temperature distribution, flow velocity and direction can be inferred from the measured temperatures. As modular systems, TSMs can be attached to a BHE at any depth. For the studied BHE, the depths of interest are 82 m and at 94 m. We recorded TSM data for 2 weeks before and during the operation of the BHE. After simulating the working fluid temperature, we model the horizontal temperature distributions using the working fluid temperatures at the depths of interest as input. We use the latter simulations for inferring groundwater flow by minimizing the root mean square error between the measured and simulated temperatures. We obtain a groundwater flow of 0.4 m/day in the NW direction and groundwater flow below the detection limit of 0.01 m to 0.02 m/day at 82 m and 94 m depths, respectively. A flow meter measurement in a nearby groundwater well confirms the flow direction at 82 m but gives an order of magnitude higher velocity, which we attribute to the measurement principle. Moreover, long-term monitoring of a BHE equipped with multiple TSMs could provide information on seasonal variations in groundwater flow, changes in the thermal properties of the BHE filling or changes in the thermal resistance between BHE and ground. |
topic |
Borehole heat exchanger BHE Groundwater flow Advective heat transport Enhanced geothermal response test Temperature sensor module |
url |
https://doi.org/10.1186/s40517-019-0152-5 |
work_keys_str_mv |
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