The relevance of energy efficiency in the world and, especially, in the European Union, is growing steadily. European Directives have been oriented towards the goal of reaching climate neutrality for 2050; requiring not only measures to increase the energy efficiency of future facilities, but also existing infrastructures. The building energy sector represents around 34% of final energy consumption, according to data from 2021 [1]. In this context, the idea of using low-temperature ground heat sources (between 40ºC and 60ºC) coupled to heat pumps or buried tube heat exchangers for powering urban heat district systems becomes attractive [2]. In the recent years, there has been a research interest in using the ground for thermal applications, ranging from using the temperature gradient as a heat source to use the ground as a thermal energy storage. Applications are numerous: urban heating, industrial heat, geothermal power production, or agriculture and food sectors. Implementing these buried systems requires forecasting their operating conditions, so the development of numerical models for predicting the thermal behaviour of the system components becomes necessary. Ground characteristics, materials, layers, number of exchanger tubes and their arrangement are factors that must be considered in the analysis [3,4]. In this work, a numerical model for simulating the thermal behaviour of the ground and heat transfer between it and a set of vertical buried tube heat exchangers, has been developed using ANSYS Fluent. These heat exchangers, known as Borehole Heat Exchangers (BHE), are typically used for heating and cooling applications in buildings. The numerical model has been validated using experimental results from previous experiments performed at the Gijón Solar Cooling Laboratory (GSCL) in the context of the Rehabilita Geosol project. The model can simulate the interaction between the heat exchanger and the ground, predicting the thermal power exchanged in both directions when the facility is operating; as well as underground heat dissipation, allowing to determine the efficiency of underground thermal energy storage.