An upscaling procedure for the optimal implementation of open-loop geothermal energy systems into hydrogeological models

Different aspects of management policies for shallow geothermal systems are currently under development. Although this technology has been used for a long time, doubts and concerns have been raised in the last years due to the massive implementation of new systems. To assess possible environmental impacts and manage subsurface energy resources, collecting data from operating shallow geothermal systems is becoming mandatory in Europe. This study presents novel advances in the upscaling of operation datasets obtained from open-loop geothermal energy systems for an optimal integration in hydrogeological models. The proposed procedure allows efficient numerical simulations to be performed at an urban scale. Specifically, this work proposes a novel methodology to optimize the data treatment of highly transient real exploitation regimes by integrating energy transfer in the environment to reduce more than 90% registered raw datasets. The proposed methodology is then applied to and validated on five different real optimization scenarios in which upscaling transformation of the injection temperature series of 15-min sampling frequency has been considered. The error derived from each approach was evaluated and compared for validation purposes. The results obtained from the upscaling procedures have proven the usefulness and transferability of the proposed method for achieving daily time functions to efficiently reproduce the exploitation regimes of these systems with an acceptable error in a sustainable resource management framework.