Satisfying demand for heating and cooling
Thermoactive geostructures provide an innovative renewable energy solution to heat and cool buildings.
They involve integrating heat exchanger tubes into geotechnical structures (deep foundations or piles, reinforced earth, tunnels, etc.). The limited depth of these structures (a few tens of metres) enables the geothermal system to help satisfy a building’s demands for both heating and cooling.
This scientific mission forms part of an ongoing strategy to both provide buildings with thermoactive foundation pile instrumentation (implemented and currently monitored by Cerema), and deliver a wide range of software and methodological solutions, designed to assess the particular thermomechanical behaviour of thermoactive foundations. It was also the result of the varied range of research and methodology work detailed below (list non-exhaustive):
LCPC research on very low energy geothermal solutions (2009-2014)
Participation in the ANR GECKO geostructures and solar storage project (2011-2015)
Co-authoring of French recommendations for the design and delivery of thermoactive geostructures (CFMS, 2015-2017)
Participation in the European cooperation in science and technology (COST) GABI project (shallow geothermal energy applications in buildings and infrastructures, 2015-2019)
Feedback from Cerema, tailored to the local climate
Cerema  was able to share its experience from the field at Sao Paulo University’s (USP) geotechnical engineering department in Sao Carlos, taking the particularities of the local climate into account.
The hot, temperate climate meant that thermoactive foundations would be intended solely to cool buildings, a significant departure from already completed French projects, which always include a heating system (air-conditioning is limited to a small number of projects).
Despite this difference, the analysis methods developed in France still proved suitable to analyse and understand results from the first life-size experiments conducted in Brazil, on the USP campus.
Furthermore, technical exchanges made it possible to understand the technical challenges revealed in Brazil’s first thermoactive pile project. Indeed, the Sao Paolo Centre for Innovation in Sustainable Construction (CICS), which incorporates a range of innovative sustainable construction techniques (for which the technical studies are currently being finalised), will be built atop thermoactive foundation piles. Under the aegis of this project, a presentation of French practices was delivered, covering the thermal and mechanical design of this process, as well as its practical applications.
 Cerema North-Picardy