The new headquarters of NSI, a true Liège-based gem offering IT solutions and services, is currently under construction in Droixhe (Liège). Located between the urban boulevard and Liège Expo, this complex is designed to accommodate up to 400 people. The first building, with a surface area of approximately 8,000 m² spread over four floors, mainly houses offices and numerous IT facilities. On the ground floor, a two-level space allows for conferences and training sessions. The second open building, approximately 7,000 m² over three floors, is dedicated to parking: a bicycle parking area coexists with the car park, equipped with numerous charging stations.
An energy design focused on sustainable performance
To move towards carbon neutrality – an ambition of the CEGEKA group to which NSI belongs – the greisch engineering office was commissioned to carry out studies on building services, structural engineering, energy design, BREEAM certification and sustainability.
The project notably included life cycle cost (LCC) analyses, the use of low-carbon concrete, and the implementation of open-loop geothermal energy. It aims to achieve BREEAM EXCELLENT certification.
A 403 kWp photovoltaic installation covers 80% of the complex’s electricity needs. Some panels are conventionally installed on the roof. Others are integrated into the façade in the form of an architectural canopy, serving a dual function: electricity production and solar shading. This solution was optimized by the greisch office to maximize natural daylight while protecting the spaces from overheating. The steel supporting structure was specifically designed to bear the additional load associated with photovoltaic panels.
Thermal energy production is ensured by heat pumps. As with the Libération complex, the proximity of the groundwater table, located at -6 m relative to ground level, allows connection to an open-loop geothermal system. The heat pumps supply reversible active ceilings, which heat or cool the spaces through convection and radiation. In addition to these functions, this aesthetic solution integrates acoustic insulation, ventilation outlets and lighting fixtures. Cooling of the main IT room is ensured by a water-source heat pump and a direct expansion system, each capable of covering 100% of the demand (redundancy). Interior and exterior lighting studies were carried out by the greisch office.
These various systems are monitored over a one-year period using a tool developed by the greisch office. This monitoring ensures the proper functioning of the installations.
Built on the former Electrabel power plant site, the two buildings – offices and parking – feature a standard structural system of columns / beams / hollow-core slabs. The floors act as diaphragms to resist horizontal loads (instability and wind actions), transferring them to the structural cores that form the “backbone” of the building. The presence of numerous deep underground remnants, sometimes beyond 5 m, prevents the use of deep foundations. The selected solution consists of soil improvement through lime stabilization over a depth of 4 to 6 m, combined with a raft foundation ensuring load distribution and overall structural stability.
This new headquarters contributes to the redevelopment of the district, alongside projects such as the urban boulevard, Liège Expo and the tram line terminus.
The actors of the project
- Client: NSI
- Delegated client: Noshaq Immo
- Architect: Syntaxe – AAST (Atelier d’Architecture du Sart Tilman)
- Engineering offices
- Structural engineering – building services, EPB manager, energy design, sustainability, BREEAM certification: Bureau greisch
- Acoustics: ATS
- Health and safety coordinator: Génie Tec
- Contractor: SM – Galère – Moury
- HVAC: Close
- Electrical works: SM Balteau-Newelec
