Bouygues Immobilier launches first large positive-energy building, the Green Office project in Meudon - 25 October 2007

Bouygues Immobilier, which won the top 2007 Eco Building Performance prize for the Mozart Tower in Issy-les-Moulineaux, is initiating a new generation of sustainable commercial buildings with the launch of the Green Office project in Meudon outside Paris.

The architectural and energy-related choices made for this building, backed by a new company approach to user behaviour, will help minimise the building's energy consumption. Furthermore, the building will produce more energy than it consumes on a daily basis.

The first large positive-energy building, Green Office was designed by architectural firm 2M. The 23,300 sq.-metre building will accommodate 400 Bouygues Immobilier employees over half the total surface area. The building permit was granted in August 2007 and work will start on the project in 2008.

• Energy consumption will be reduced to the strict minimum as a result of the bioclimatic design of the building and a high-performance natural ventilation system:
  - advantage has been given to a north-south building orientation;
  - the outer walls have enhanced external insulation, with wood and aluminium joinery for improved performance, and motor-controlled vents for natural ventilation;
  - the open-plan office space is 13.50 metres deep, making it easier to make full use of natural lighting and ventilation;
  - air circulating fans enhance comfort levels in summer;
  - motor-controlled external blinds provide good solar protection;
  - the thermal inertia of the floor slabs is made more readily accessible by dispensing with false ceilings and raised floors.

• Lighting in the building has been designed to contribute to energy savings while still providing maximum comfort levels. The office floors will have diffuse ambient lighting complemented by a system of lighting concentrated on work areas (desk lamps, standard lamps). Control of lighting has been optimised to reduce power consumption by automatically turning lights off when the office is not occupied.

• The design of the stairs (spacious, abundance of natural light, etc.) will incite the building occupants to use the stairs instead of the lifts.
  

Relying exclusively on renewable energies, the building will produce 64 kWh/sq. metre/year and consume 61 kWh/sq. metre/year, all uses combined. Green Office will reduce power consumption by 60% compared to a standard building constructed to the RT 2005 thermal regulations, and by 30% relative to the most energy-efficient buildings on the market today.

More than 5,000 sq. metres of solar panels will produce energy for the building. They will be installed:
- on walls (as spandrel panels, brise-soleil sun fins, and on the roof);
- as “car ports” in outdoor parking areas.

The building will also use a biomass combined heat and power system fuelled by wood or oil. The heat produced will cover the building's entire heating requirement, and the electricity produced will cover power needs above and beyond the capacity of the solar panels.

The architectural and power arrangements implemented will cover power consumption for heating, lighting, lifts and car parks. The building will also be provided with latest-generation technological equipment enabling it to cover the power consumption of office systems as well.

Compensating the building’s energy consumption by generating renewable energy means the project is carbon-neutral. In addition, special attention will be given to reducing its carbon footprint by limiting carbon emissions during construction.

A supervisory building management system will also be installed to check the energy balance and control the thermal comfort of the building throughout the year.

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Green Office is destined to be the benchmark commercial building in terms of energy savings and sustainable development.

Through this exemplary project, Bouygues Immobilier is set to be at the cutting edge of environmental innovation.