Simulation of a geothermal aquifer storage in Brussels showing the need for a better balanced system with regards to the local hydrogeological conditions

An Aquifer Thermal Energy Storage (ATES) system was started in 2014 in the center of Brussels using the Landenian confined aquifer for heat and cold needs of an administrative building. Unfortunately, the imbalance between the injection of warm and cold water combined with the local hydrogeological conditions, has led rapidly to thermal interferences between the heat plume and the cold wells. A second ATES system located nearby started to operate around August 2017 for the heat and cold needs of another large administrative building. In the scope of the MUSE project (GeoERA/ERA-NET program), a numerical model was built using FEFLOW® to simulate groundwater flow and heat transport in the confined aquifer. After calibration on the available piezometric and temperature data, realistic scenarios were simulated to determine possible interferences and to image the year after year persisting and growing heat plume in the aquifer. Results show that even if the heat plumes of the two systems had come into contact, the influence of the second system on the first one was negligible during the first two years of joint operation. Indeed, for a longer period, simulated results pointed out that due to the thermal imbalance and the limited advection in the aquifer, the groundwater temperature would rise inexorably in the warm and cold wells of both systems. A business as usual scenario will lead to a decrease in efficiency for both systems. This case-study is showing how it could be difficult to find an optimum with regards to the local hydrogeological conditions. If advection is very important, thermal energy cannot actually be stored locally as heat and cold plumes are transported far away from the wells. On the contrary, if advection is limited, a global thermal balance is required for hot and cold injections. If advection is moderate (as in this case study), a detailed simulation of the groundwater flow and heat transport in the aquifer is required to find out if the annual imbalance can be managed in relation to the specific local hydrogeological conditions

Geomechanical modeling of the recent post-industrial uplift in Brussels and comparison with geodetic InSAR measurements

Radar interferometry (InSAR) measurements have provided recent evidence of ground movements, particularly a slight uplift in north-western areas near the center of Brussels in response to changes in groundwater pumping and drainage linked to decreased industrial activities within the city. Historical potentiometric head changes between 1970 and 2020 are translated in water pressures transmitted to 1D vertical models coupling the vertical flow (and subsequent water pressure variations) with geomechanical swelling/consolidation calculations. The discretization of the 1D model is refined in the most compressible layers to obtain an accurate transient propagation of the water pressure changes and thus a better estimation of the swelling/consolidation values. The total uplift (or subsidence) is compared to the estimations obtained from the InSAR data processing. A detailed interpretation of such a comparison is not straightforward. Many factors and uncertainties can also play an important role in the estimated values from the processing of the InSAR measurements, as in the calculated values from the coupled hydrogeological-geotechnical models.LASUGEO project—monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements11. Sustainable cities and communitie

Modeling recent uplift caused by decreased groundwater extraction and revealed by geodetic InSAR measurements in the Brussels area

peer reviewedRadar interferometry (InSAR) measurements have provided recent evidence of ground movements, particularly a slight uplift in north-western areas near the center of Brussels in response to changes in groundwater pumping and drainage. A 3D transient groundwater model is developed and calibrated to simulate the historical potentiometric head changes between 1970 and 2020. The corresponding water pressures are then transmitted to 1D vertical models coupling the vertical flow (and subsequent water pressure variations) with geomechanical swelling/consolidation calculations. The discretization of the 1D model is refined in the most compressible layers to obtain an accurate transient propagation of the water pressure changes and thus a better estimation of the swelling/consolidation values. The total uplift (or subsidence) is compared to the estimations obtained from the InSAR data processing. A detailed interpretation of such a comparison is not straightforward. Many factors and uncertainties can also play an important role in the estimated values from processing the InSAR measurements, as in the calculated values from the coupled hydrogeological-geotechnical models.LASUGEO: monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements9. Industry, innovation and infrastructur

La psychopathologie: Une approche cognitive et neuropsychologique

La psychopathologie cognitive est un champ d'investigation nouveau qui se propose d'utiliser les concepts et les méthodes de la neuropsychologie cognitive - et, plus largements des sciences cognitives et des neurosciences - afin d'étudier les dysfonctionnements de la cognition qui accompagnent les troubles psychiatriques. L'objectif de cet ouvrage, issu du forum thématique annuel de la Société de Neuropsychologie de Langue Française, est de présenter les objectifs et les méthodes de cette approche et de l'illustrer dans différents domaines de la psychopathologie. Les domaines abordés concernent les hallucinations, les illusions et croyances, l'anxiété, la dépression, le trouble obsessionnel compulsif, l'autisme, la schizophrénie, le stress post-traumatique, les troubles dissociatifs, l'ictus amnésique, la psychopathie et la sociopathie (...). Ce livre s'adresse à tous les cliniciens et chercheurs, en formation ou confirmés, confrontés à l'étude, l'évaluation et la prise en charge des troubles psychiatriques (psychiatres, neurologues, psychologues, orthophonistes, ergothérapeutes)

Modelling interactions between three Aquifer Thermal Energy Storage (ATES) systems in Brussels (Belgium)

peer reviewedShallow open-loop geothermal systems function by creating heat and cold reserves in an aquifer, via doublets of pumping and reinjection wells. Three adjacent buildings in the center of Brussels have adopted this type of aquifer thermal energy storage (ATES) system. Two of them exploit the same aquifer consisting of Cenozoic sands, and started operation in 2014 and 2017, respectively. A previous hydrogeological model developed by Bulté et al. (2021) has shown how the thermal imbalance of one of the systems jeopardizes the thermal state of this upper aquifer. Here, the interactions with a more recent third ATES system located in the deep aquifer of the Palaeozoic bedrock are studied and modelled. After being calibrated on groundwater flow conditions in both aquifers, a 3D hydrogeological model was used to simulate the cumulative effect of the three geothermal installations in the two exploited aquifers. The results of the simulations showed that although the hydraulic interactions between the two aquifers are very weak (as shown by the different observed potentiometric heads), heat exchanges occur between the two aquifers through the aquitard. Fortunately, these heat exchanges are not sufficient to have a significant impact on the efficiency of the individual geothermal systems. Additionally, this study shows clearly that adding a third system in the lower aquifer with a mean power of 286 kW for heating between October and March and an equivalent mean cooling power between April and September is efficient.7. Affordable and clean energ

Numerical modeling of the interference of thermally unbalanced Aquifer Thermal Energy Storage systems in Brussels (Belgium)

A numerical model was built using FEFLOW® to simulate groundwater flow and heat transport in a confined aquifer in Brussels where two Aquifer Thermal Energy Storage (ATES) systems were installed. These systems are operating in adjacent buildings and exploit the same aquifer made up of mixed sandy and silty sublayers. The model was calibrated for groundwater flow and partially for heat transport. Several scenarios were considered to determine if the two ATES systems were interfering. The results showed that a significant imbalance between the injection of warm and cold water in the first installed ATES system led to the occurrence of a heat plume spreading more and more over the years. This plume eventually reached the cold wells of the same installation. The temperature, therefore, increased in warm and cold wells and the efficiency of the building’s cooling system decreased. When the second ATES system began to be operational, the simulated results showed that, even if the heat plumes of the two systems had come into contact, the influence of the second system on the first one was negligible during the first two years of joint operation. For a longer modeled period, simulated results pointed out that the joint operation of the two ATES systems was not adapted to balance, in the long term, the quantity of warm and cold water injected in the aquifer. The groundwater temperature would rise inexorably in the warm and cold wells of both systems. The heat plumes would spread more and more over the years at the expense of the efficiency of both systems, especially concerning building’s cooling with stored cold groundwater

Predicting interactions between three neighbor open-loop Aquifer Thermal Energy Storage (ATES) systems in two overlaying aquifers in Brussels (Belgium)

peer reviewedShallow open-loop Aquifer Thermal Energy Storage (ATES) systems have been adopted by three large adjacent buildings in the centre of Brussels. The doublets of pumping and reinjection wells of two administrative buildings are located in a shallow aquifer made of Cenozoic mixed sandy and silty sublayers and operations started in 2014 and 2017. A third ATES system located in the underlying deep aquifer made of Palaeozoic fractured phyllites and quartzites, was started recently (2020) to provide the needed heating and cooling power to a large multi-service building. Groundwater levels variations in these two aquifer systems are different and pumping tests performed in the upper aquifer system have shown no impact on the groundwater levels in the Palaeozoic bedrock aquifer. After being calibrated on groundwater flow conditions in both aquifers, a 3D hydrogeological model using Feflow© was developed to simulate the cumulative effect of the three geothermal installations in the two exploited aquifers. In terms of heat interactions, a previous model has shown how the thermal imbalance of the ATES system started in 2014 was jeopardising the thermal state of the upper aquifer (Bulté et al. 2021). Here, interactions with the third ATES system located in the deep aquifer are studied and modelled with different operational scenarios. Even though hydraulic interactions between the two aquifers are very limited, heat exchanges occur between the two aquifers, through an aquitard formed by low permeability Cretaceous base deposits and the weathered top of the bedrock. The simulation results show that despite the unbalanced ATES system affecting mainly the shallow groundwater conditions, an adjacent but deeper ATES system can operate without significant interactions. Acquisition of additional measured data (i.e., piezometric heads, groundwater temperatures, detailed pumping, injection flow rate, etc.) will be crucial to improve the reliability of the simulated results for different operational scenarios. This will be particularly useful for the future management of the three ATES systems in order to avoid losses in both efficiency and durability.7. Affordable and clean energ