This Ph. D. thesis begins with the development of the European project GeoCool, aimed at the introduction of ground coupled heat pump systems into the Southern European markets. This project has been the first that has integrated different fields of engineering involved in the design and implementation of such systems operating in reversible mode, being one of the first monitored installations that works in both modes, heating and cooling. The main objective of this work is to validate the tools for the design of ground coupled heat pump systems, whose efficacy depends not only on the accuracy of their calculations but on the skills of designers to choose appropriate models and their input parameters. Hereby GeoCool installation model has been done with the TRNSYS simulation software and it has been validated experimentally. The model validation has been performed by comparing the results of the seasonal performance factor obtained in the simulation with the calculated from experimental data. The results show that the predictions of the simulation approach rather accurately to the experimental data, especially if the model incorporates aspects of the actual functioning of the installation as the use of the heat pump at partial load.