The integration of geothermal heat exchangers into structural foundation elements offers an attractive opportunity to reduce the installation costs of ground source heat pump (GSHP) systems while improving the energy performance of buildings. Among these technologies, energy piles (or thermo-active piles) combine the structural function of foundation piles with the ability to exchange heat with the ground, eliminating the need for separate borehole heat exchangers in many applications. However, the interaction between thermal cycles and structural loads must be thoroughly understood before these systems can be widely adopted in engineering practice.
The PITERM project was launched within the Spanish INNPACTO 2011 programme to investigate the thermo-mechanical behaviour of geothermal foundation piles and develop new design methodologies for their implementation in buildings. The project brought together CEDEX, the Universitat Politècnica de València (UPV) and the industrial partners Rodio-Kronsa and Energesis in a public-private collaboration aimed at advancing the scientific and technical knowledge of thermo-active foundations.
A central achievement of the project was the design, construction and instrumentation of a full-scale precast geothermal pile installed at the UPV campus. The experimental pile was subjected simultaneously to controlled mechanical loading and programmable heating and cooling cycles, enabling researchers to evaluate the combined effects of structural, geotechnical and thermal actions under realistic operating conditions. An extensive monitoring system recorded temperatures, strains, displacements and mechanical loads throughout the testing campaign, providing one of the first comprehensive experimental datasets for thermo-active piles in Spain. The experimental results were complemented by numerical modelling to validate new design approaches and improve the prediction of long-term pile performance. The knowledge generated by PITERM demonstrated that geothermal energy piles can provide efficient renewable heating and cooling while maintaining their structural integrity and load-bearing capacity. The project established important design criteria for thermo-active foundations and contributed to the development of engineering guidelines that support the wider implementation of shallow geothermal systems in buildings. Moreover, PITERM laid the scientific foundation for subsequent geothermal research activities at ITACA-UPV, reinforcing its expertise in innovative ground heat exchanger technologies and energy geostructures.
“PITERM” was funded by the National Plan for Scientific Research, Development and Technological Innovation (2008–2011).
