The first reproducible green office buildings
with positive energy

An innovative project par excellence, Solaris already figures as a benchmark for the future RT 2020 sustainability framework. The initial idea was to erect a building which generates more electricity than it consumes.

To achieve such high performance, SERCIB has formed a multi-disciplinary team of outstanding experts, including architectural design by the “Architecture et Environnement” practice, thermal, static and thermodynamic design offices, and economics and innovation consultants.

Solaris is a concept that can be reproduced on demand for units of 5,000 sqm. In the present case, the Clamart municipality will take delivery of the first Solaris green building (31,000 sqm), 25,000 sqm of which have just been rented by Kraft Foods France. Schedule delivery end-2013.


Key figures

  • 31,000 sqm.
  • App. 4,000 sqm of solar roof panels.
  • 116 geothermal probes going down to a depth of 100 m.
  • The structure comprises two separate buildings, A and B, each with a surface area of 15,000 sqm.
  • Average module size of 5,000 sqm.
  • Average depth of modules: 18 metres.
  • Floor clearance: 2.70 metres.
  • 876 car parking places, 88 places for motorcycles and bicycle  parking.
  • 1,000 sqm of interior gardens.
  • Terraces on upper floors.

Saving to produce more efficiently

Before it starts to generate electricity, a building must start by cutting down on energy use. The first objective in the design of Solaris was thus to achieve even more exacting cuts in energy consumption than those required by France’s BBC low energy-consumption building standard.

This was made possible by:

  • A north-south layout and an optimized building shape.
  • Insulation via the outer shell of the building by abolishing thermal bridges, combined with energy-efficient glazing.
  • The use of thermal inertia (internal mass).
  • Night-time over-ventilation.
  • Regulation GTB.
  • Use of geothermal energy.
  • A garden creating a microclimate.

Smart Management

About the lighting:

  • The light fittings are equipped with low-consumption bulbs.
  • Lights go on only when users are present.
  • The lighting adapts to exterior lighting levels using dimmers.

About temperature control:

  • The energy is stored in the floors using a network of water coils incorporated in the slabs.
  • The heat generated during daytime building use is absorbed.
  • In winter, 120 thermal probes tap the heat generated by the enormous mass of earth 100 metres underground and inject it inside the building. In summer, the opposite happens.
  • The dual regulation system is computer controlled.
  • During mid-seasons, night-time over ventilation is used to store cold in the building’s interior structures.

This combination of technologies will enable Solaris to halve its energy bill, taking energy costs (before solar panel generation) to around €7/sqm/year, compared with €16/sqm/year for an equivalent RT 2005 building.


Transparent, self-regulating Texlon® roofing used to create a microclimate at garden level.



Solar and temperature sensors cause the upper air chamber to be pressurised allowing light to penetrate through the gestalt graphics.



As internal temperatures in solar gains increase, the lower air chamber is pressurised reducing the level of light and solar gain penetrating the space.

The Earth and the Sun at the heart of Solaris

Once it has managed to reduce its energy consumption, Solaris can generate renewable energy.
This is how it can become a positive energy building according to French RT 2005 calculation rules. To achieve this degree of performance, Solaris takes its energy from two natural sources: the sun and the earth, by combining:

  • A roof installation comprising about 4,000 sqm of solar panels (the biggest roof installation in the Greater Paris region on a service building).
  • 116 geothermal probes 100 metres deep, for a total of 12 km!

Combining these two systems enables Solaris to offset its energy requirements and make substantial CO2 savings.


for further details: contact us

Positive energy green building concept

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