Contractor

Name : SNC AER 2 – AMO ORFEO DEVELOPPEMENT

Construction Manager

Name : Maîtres d'œuvre principaux : Agences Viguier et Sisto Studios - Setec tpi MOE structure - Atys MOE fluides - Artelia MOEX – AE75 Economiste

Stakeholders

Function : Contractor

SNC AER 2

Function : Assistance to the Contracting Authority

ORFEO DEVELOPPEMENT

Morgane Koenig

Function : Assistance to the Contracting Authority

G-ON (étude carbone)

Function : Designer

Agence Viguier

Laure Barthelot, Thomas Poletti

Function : Designer

Sisto Studios

Function : Construction Manager

Artelia Bâtiment Ile-de-France

Function : Structures calculist

setec tpi

François Lebrun

Function : Other consultancy agency

Atys Engineering

Function : Other consultancy agency

Bollinger Grohmann

Function : Others

AE75 (économiste)

Function : Others

SOCOTEC (Bureau de contrôle)

Function : Others

Petit (groupe Vinci)

Energy consumption

• Primary energy need : 74,38 kWhep/m².an
• Primary energy need for standard building : 149,68 kWhep/m².an

Calculation method : RT existant

Breakdown for energy consumption : 71 kWhEP/m²/year. Heating and DHW are produced via connection to the Enertherm heating network, air conditioning by connection to the cooling network of the same name and the rest of the uses consume electricity. In addition to these consumptions on the regulatory uses of energy, other electricity consumptions should be taken into account (office automation, servers, elevators, common areas, etc.). These consumptions are estimated at approximately 31 kWhEF/m²/year thanks to the ratios of the E+C- method.

• Initial consumption : 157,59 kWhep/m².an

Systems

Heating system :
• Urban network
Hot water system :
• Urban network
Cooling system :
• Urban network
Ventilation system :
• Double flow
Other information on HVAC :

Heating and DHW are produced via connection to the Enertherm heating network, air conditioning by connection to the cooling network of the same name and the rest of the uses consume electricity.

Urban environment

The Aurore complex is located in the town of Courbevoie, west of Paris, in the Hauts-de-Seine department, in the Gambetta district. It takes place in a dense urban fabric, made up of towers, on the edge of the slab, and adjoins the city of Courbevoie and the circular boulevard. The set proposes a complete redevelopment of the site thanks to its new influence and the deconstruction of slabs and buildings in its immediate environment. Thus, it frees up public spaces at the foot of the Tower, at the level of the slab of La Défense and Courbevoie. It actively participates in the opening up of commercial sectors in the immediate vicinity through the removal of portions of slabs. It promotes access from the circular boulevard, which will benefit the whole district, simplifying its service. And finally, the stairs built around the project reconnect the city of Courbevoie and the different pedestrian levels of La Défense.

Product

Biomass heating network Idex La Défense (formerly Enerthem)

https://www.idex.fr/

Product category : Génie climatique, électricité / Chauffage, eau chaude

The new Aurore Tower is connected to the business district's heating network for the production of heating and domestic hot water.

In 2021, this heating network began its transformation: the biofuel originally used to power the boiler room was replaced by agropellets. Made from raw materials of agricultural origin (green waste, rapeseed or corn straw, miscanthus, walnut shells, olive pits, vine shoots), this solution will ultimately significantly reduce the energy impact of the neighborhood , reducing CO2 emissions by 54,000 tonnes per year.

Construction and exploitation costs

• Total cost of the building : 99 984 650 €
Additional information on costs :

The restructuring of the Aurore tower allowed a cost reduction of 30 to 40% compared to a new reconstruction.

The site was completed more quickly and therefore the promoter was able to rent his tower more quickly, which represents a significant saving.

Reuse : same function or different function

Batches concerned by reuse :
• Structural works

For each batch : Reused Materials / Products / Equipments :

Batch affected by reuse: structural work

The concrete volume preserved thanks to the extension of the life of the existing tower is estimated at approximately 15,310 m3. A quantification of the materials of the structure was carried out by crossing data from the plans of the project, the plans of the existing (DOE of 1967) and the digital model.

Environmental assessment

Impacts avoided : water, waste, CO2 :

Given the specificity of this project (conservation of a concrete structure but no reuse/reuse in situ or external sourcing of materials), the tool for calculating avoided impacts was not suitable and was therefore not used.

An environmental study conducted by G-ON quantified the benefit of preserving the structure instead of demolishing it. When only the CO2 emissions from the Environmental and Health Declaration Sheets of the materials making up the structure of the Tour Aurore are counted, the difference between the project and its variant (which consists of demolishing the structure to rebuild a news). The difference between the two variants includes the following steps:

1. Demolition of the structure and disposal or recycling of materials;
2. Construction of a new structure.

The environmental data used are those of the FDES when a sheet has been selected from the INIES database. For certain categories of concrete not appearing in the INIES database, the BETIE software was used to generate a specific FDES. The quantification of the environmental impact was a driving force in the choice of preservation.

The life cycle GHG emissions of the Aurore tower structure correspond to 5,621 tonnes of CO2 equivalent. These emissions emitted during construction had a considerable impact on the environment, hence the importance of its preservation. Impacts on the climate, to which the material impact should have been added: the management of approximately 42,400 tonnes of waste generated by the demolition (approximately 1,500 semi-trailers), as well as significant nuisances on the environment near the tower during of the construction site.