The project belongs to a larger urban intervention with the new Grand Parc in Bordeaux, with green area and public spaces, and it occupies a central place in redefining the neighbourhood. It also has an identity vocation because it constitutes a visual catch from the perspective created by the plot where it is located. The volume, simple but slightly decomposed, expresses the public and private use of the building and highlights a forecourt that opens on the urban project of the Grand Parc.
The building has around 3000 m2 of dwellings distributed on 4 floors and further public spaces in the other two floors (ground/first floor). The diversity of the outdoor spaces and the perforations of the facades individualizes each apartment and accentuates the desired effect of lightness. Balconies, terraces and loggias provide privileged, diverse and intimate outdoor spaces for residents. The project is subject to strict environmental specifications, demanding in particular compliance with the Agenda 21régional and Aquitain Plan Climat and obtained Habitat & Environment certification.
The envelope is prefabricated with wood frame walls from a company located in the South-West. These modules have reduced the carbon impact by the quality of assembly, saving time of implementation and reducing waste on site. The facades have been designed to protect from the sun in summer and naturally ventilate the building. The envelope contains perforated parts, behind which are the joinery. These openings give the hand to users to manage their comfort. Air brewers are installed in the meeting rooms and relax to offer a better ambient temperature during warm periods.
The air Tightness Value measured with the blower door test account for 0.48 kg/ m s Pa
Concerning the heating system, the radiators installed in the building are "Q.rad": it is an innovative technology able to use the heat generated by the cores of processors making calculations to heat homes and offices (energy fatally produced). These Q.rad offer free heating but they also offer services such as wifi (which removes any additional equipment) and feedback on the comfort and consumption of the building. This innovation is developed by a French company, it offers a real technical simplification of the building: no water, no valves, no leaks, no external maintenance. The stakeholder aims to reach the Positive Energy Building target, an ambition to which was added a large number of performance constraints on the part of Gironde Habitat, including the significant reduction in the energy bill for tenants. The project management team then took a proactive approach to find an economical and innovative solution. Instead of a conventional photovoltaic installation analyzed the operation and consumption of existing achievements of the department before proposing a relevant heating technology. Thus was proposed the Qarnot Computing system, Q.rad radiators that generate energy called "fatal", that is to say the energy produced by a process whose purpose is not the production of this same energy which, if it is not recovered and / or recovered, is lost.
All the actors of the Department (energy, IT, heritage services) have been deeply involved in understanding this new technology and its business model, the beginnings of the connected building of tomorrow. As for housing in Gironde Habitat, this technology will provide tenants with free heating and internet access; a step forward in the fight against energy and digital poverty. But this technological and innovative choice was not a technical answer alone. It served as a lever to change the way we designed and built a building. Concretely, this one was conceived around its heating system and not the opposite. In close consultation with the Department, the designers used the Q.rad machine to make the pole more technically frugal and therefore easier to maintain and evolve over time.
Concerning the building management system, based on the digital skeleton and sensors offered by the Q.rad, it is possible to better monitor and control building consumption, the indoor air quality of the premises and the occupancy of meeting rooms; tools to improve the quality of use of the building and provide more comfort to users. An installed application centralizes this information and is made available to users in common areas.
According to the technologies installed, the primary energy need accounts for 56.10 kWhpe/m2 year, significantly lower than the 151 kWhpe/m2 year of a standard building. The measurements of real energy consumption allowed to breakdown as following:
- Heating: 58 400 kWh
- Domestic Hot Water: 2500 kWh
- Lighting: 19,000 kWh
- Auxiliaries: 9000 kWh
- Process: 19 200 kWh
- Parking: 3176 kWh