Design of an ATES system in a heterogeneous aquifer to supply a small urban site with high demand: Imperial College London’s South Kensington campus

Aquifer Thermal Energy Storage (ATES) systems offer a promising way to decarbonise heating and cooling in dense urban environments, but their performance depends on reliable operation within geologically heterogeneous aquifers and under time-varying building demand. Beneath central London, the Chalk aquifer is highly heterogeneous, which leads to complex thermal plume behaviour and potential for significant thermal interference when multiple boreholes are deployed on a confined urban site. This study presents the design of a large ATES system proposed for Imperial College London’s South Kensington campus, a small site (dimensions) with high heating demand. 

The simulated system configuration and operating limits are based on previously developed probabilistic scoping scenarios (Jackson et al., 2026, EGU26).  Monte Carlo sampling of uncertain design and operational parameters was used to define feasible ranges of ATES performance. In the present work, we choose to take forward selected probabilistic scenarios for detailed numerical simulation to investigate their behaviour under realistic geological and operational constraints. 

A bespoke dynamic flow-rate controller is implemented in the simulator through explicit time-dependent borehole boundary conditions. The controller continuously adjusts individual doublet flow rates to meet heating and cooling demand derived from campus load profiles, while also accounting for evolving production temperatures and heat-pump performance. Flow is allocated across a ranked subset of doublets ordered by inter-borehole distance: the most widely spaced doublets are activated first, and progressively closer doublets are only activated as demand increases. Partial loading of marginal boreholes is allowed, and automated temperature-based shut-downs are applied to borehole doublets whenever production temperatures fall below (warm boreholes) or exceed (cool boreholes) the ambient groundwater temperature, to manage thermal breakthrough. 

The base-case simulation represents a P50 probabilistic scenario and includes five active ATES doublets. Lateral plume spreading through high permeability karst intervals in the Chalk aquifer leads to thermal interference and, in some boreholes, thermal breakthrough, which is managed using the borehole flow-rate control system. Despite the complex plume development in the aquifer, the system can deliver the target heating and cooling demand. This would not be possible if the boreholes had been spaced based on multiples of the thermal radius, as is commonly done. Here, allowing thermal interference reduced thermal recovery but supplied higher heating and cooling that could be achieved by a system designed to avoid interference. Thermal breakthrough was managed by monitoring borehole temperature and controlling production in response to this. Our results suggest that high borehole density coupled with active borehole monitoring and control may be preferable in dense urban environments to maximize energy supplied.