Optimizing energy storage and reproduction for Aquifer Thermal Energy Storage. A scientific approach in enhancing ATES system performance at Achmea Apeldoorn through application of smart extraction and infiltration strategies.

Abstract

In the subsurface beneath the campus of Apeldoorn Achmea, the groundwater flow velocity is high. This causes a problem for its Aquifer Thermal Energy Storage (ATES) system: Infiltrated water with thermal energy may be lost from the systems range if it is extracted with the accustomed control strategy. In this research project, an analytical model was built in an Excel work sheet, to quantify the thermal energy distribution within the subsurface under influence of infiltration and extraction by 2 hot wells and 2 cold wells. This quantification should help to gain insight in how to smartly manage thermal energy distribution through varying infiltration and extraction rates. Studying the physical processes concerning ATES, geohydrological subsurface characteristics, and ATES system characteristics led to the creation of the analytical model in which a variety of problem related parameters can be adjusted and ultimately the infiltration and extraction rates can be adapted. The analytical model is validated qualitatively and with the numerical groundwater modeling program PMWIN. Optimization of the accustomed infiltration and extraction rates is performed according to 3 strategies. The results of these 3 strategies are judged on its quality with a set of assessment criteria. This resulted in a chosen 'useful optimized control strategy' which reduced energy loss from the system through varying the infiltration and extraction rates. This 'optimized control strategy' showed to be very robust.