Terrendis geothermal probes chosen for a tertiary sector eco-renovation project - a first in Europe


Elydan Group Terrendis geothermal probes chosen for the KTR France positive impact eco-renovation project - a first in Europe

Terrendis, a subsidiary of the Elydan Group specialising in heating and renewable energies was chosen to supply 4 geothermal probes as part of the first tertiary sector eco-renovation with positive energy and storage, designed and installed by Diagonal Concept on behalf of KTR France. The solar heat energy produced by the hybrid solar panels is stored in the rock at a depth of 150 m by the vertical probes and recovered by them to heat and cool the 854 square metres of the building.

A tertiary sector positive energy eco-renovation project unique in Europe

KTR France is a subsidiary of the German industrial company specialising in high technology mechanical components and focussed on innovation. In 2016, KTR acquired a somewhat run-down 1970s building in Dardilly on the western outskirts of Lyon with the intention of transferring its head office to France. Pierre Martin, KTR France Director, mindful of the well-being of his staff, wanted to carry out an exemplary eco-renovation to reflect the values and image of the Group. The idea was to obtain a building that produced more energy than it consumed and aim for energy self-sufficiency. Marc Campesi, Director of Diagonale Concept consultants and architects took up the challenge of refurbishing the building with the following goals:

  • Create a positive energy building combining high-performance insulation with an energy mix of solar, geothermal, heat pumps and so on
  • Incorporate a low-carbon ethos by using biosourced or recycled materials, choosing local suppliers, providing charging points for electric vehicles, etc.
  • Create a smart, connected building to provide performance indicators
  • Promote biodiversity by installing beehives, choosing local species, providing bird shelters, etc.
  • Create a building that imparts knowledge and showcases the technology (company training, school visits, etc.)
  • Put the well-being of the users and their quality of life at work at the heart of the project by providing planted areas, a bright environment, sit/stand desks, a shared vegetable garden, etc.

After 18 months of planning and construction work, the building was handed over in 2018 and meets all its objectives by producing 42 MWh and only consuming 26 MWh.

The Group Elydan Terrendis geothermal probes used to store energy in the rock

As part of the positive energy eco-renovation, Diagonale Concept chose the geothermal solution that was most suitable in ecological terms. The process stores solar heat energy in the rock at a depth of 150 m via a battery of 4 geothermal probes. The energy is then retrieved by a glycolated water/ordinary water heat pump and used to heat or cool the entire building.

At present, people are happy with passive buildings, but more needs to be done! Geothermal energy is vital to this all-encompassing project. We chose Terrendis geothermal probes as they provide extreme resistance to impacts, cracking, scratching, etc. and have an estimated service life of over 60 years.

Geoforage took two weeks to install the battery of 4 French-made, special polymer resin, 32 mm diameter Terra Extrem vertical probes at a depth of over 150m.
Elydan Group Terrendis geothermal probes were chosen for:
– Their geothermal heat capture performance
– Their burial depth: 60 m to 150 m
– Their technical performance that reduces thermal fluid resistance and load losses

Terrendis products contribute to better energy performance in the construction sector. We strive to provide our customers with solutions that respect the environment and products whose quality is beyond reproach, just as we did when the KTR France head office was refurbished.

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