## 3 Results
### Heat Transport Simulations
#### 3.2.2 Scenario Simulation Results  
Ongoing and future conditions for the three ATES systems are calculated from 1 January 2014 until 31 March 2040, with no evolution in time of the power used for heating or cooling. For scenario 1 (reference scenario), the temperature increases year after year in the warm (WW) and in the cold wells (CW) of Buildings 1 and 2 (Figure 7). As commented by [PERSON] et al. [3]: _\"a step increase was simulated in the hot wells at each spring period corresponding to the start of each building cooling period and thus to injection of hot water in the hot wells'_. The simulated temperature increases systematically during the whole summer period in the hot wells. This is also the case in the cold pumping wells, and after 2016, the coldest spring temperatures continued to shift higher and thus continued to rise during the summer. As indicated previously [3], the Building 1 imbalance (i.e., requiring less energy for heating than cooling), is causing this trend for both Buildings 1 and 2. A step temperature decrease is also simulated in the cold injection wells at the beginning of the winter, and the temperature decreased during the whole period. Then, the temperature also decreases slightly near the hot wells but never reaches back to the initial natural temperature. In the long term, the coldest simulated temperatures that can be found at the beginning of the summer period in the hot wells continue to increase each year from 12.4 and reach 21 \({}^{\circ}\)C in 2039. Figure 7: Simulated long-term evolution of the mean temperature in the hot and cold wells starting from the natural background temperature of groundwater around 12.4 \({}^{\circ}\)C for Buildings 1 (**above**) and 2 (**below**). For Building 3, starting from the initial 12.4 \({}^{\circ}\)C in the deep aquifer, the simulated evolution of the mean temperature in the hot and cold wells does not show any trend (Figure 8). This results from the well-balanced power needs for heating and cooling combined with the limited influence of the shallow aquifer changes on the deep aquifer conditions. This is indeed very positive for the current and future efficiency of the ATES. Simulated heat and cold plumes in the shallow aquifer show the negative thermal interferences between the heat plume and the cold wells of the Building 1 and 2 systems (Figure 9) and the progressive temperature increase in the cold wells. Consequently, in this aquifer, the cold storage becomes less efficient year after year. In the deep aquifer, heat plumes are logically seen around the hot wells at the end of the summer. Slight heat plumes are also simulated in this aquifer and are located just below the hot wells of Buildings 1 and 2 in the upper aquifer. This shows that the hot plumes in the shallow aquifer induce only a limited influence on the deep aquifer. The heat and cold plumes are simulated for more than 20 years for operation with the power use maintained at current levels (Figure 10). On 1 October 2039, it appears that the large heat plume generated in the upper aquifer (Figure 10, left) does not impact the cold wells in the deep aquifer (Figure 10, right). From the reverse perspective, the hot and cold plumes generated in the deep aquifer by the ATES system of Building 3 do not have a significant effect on the shallow aquifer and hot and cold wells of Buildings 1 and 2. Figure 8: Simulated long-term evolution of the mean temperature at the hot and cold wells for Building 3. However, as expected, in the shallow aquifer, the cold wells of Building 1 and to a lesser extent also those of Building 2, are affected by the large heat plume from the hot wells of Building 1. Figure 10: Simulated heat and cold plumes for 1 October 2039 in the shallow (**left**) and in the deep (**right**) aquifer. Figure 9: Simulated heat and cold plumes for 1 October 2020 (end of the first cooling period of Building 3) in the shallow (**left**) and the deep (**right**) aquifer.