Fig. 1From: Potential of low-temperature aquifer thermal energy storage (LT-ATES) in GermanySchematic operation principle of ATES in cooling mode (left) and in heating mode (right). The hydrogeological criteria aquifer productivity, iron and manganese contents in groundwater and groundwater flow velocity as well as the climatic criterion represented by cooling degree days (CDDs) and heating degree days (HDDs) are included for illustration purposesBack to article page