Applying coupled numerical model in the design of ATES facility in a contaminated urban environment

Within the KONATES project, an Aquifer Thermal Energy Storage (ATES) system is planned in the scientific park of Leipzig, where the groundwater is contaminated with chlorinated volatile organic compounds (Cl-VOCs). Supported by the SpeicherCity project, corresponding numerical model is being further developed and applied to study the environmental impact of ATES operation.

From the regulatory perspective, the operation of ATES system in the urban area should not induce temperature changes beyond a few degrees Celsius at the boundary of the properties. The challenge faced in the KONATES project is that this temperature limit will be quickly exceeded, as the injection temperature is planned to be ca. 80°C. This requires a careful planning on the timing, duration, and location of the injection, as well as the pumping rate.

To satisfy the regulatory requirements and facilitate the understanding of such impacts, a 3D numerical model has been constructed, simulating both hydraulic and heat transport process in the aquifer. The model is capable of predicting the propagation of the thermal plume in response to different design of injection temperature and flow rate. Due to the high groundwater velocity, it shows that at a pumping rate of 600 l/h, injection can only be carried out for 12 days continuously without increasing the groundwater temperature more than 2°C at the boundary.

The next step of model development is to include feature that reflects the elevated mobility of the Cl-VOCs, which is relevant to the quantification of extracted contamination in the surface treatment facility.