Brussels, 20 December 2023 – An office complex powered by no fossil fuels: Immobel, Belgium’s largest listed property developer, is responding to growing ecological awareness in the dynamic European quarter with office complex Commerce 46. To carry out this project, the developer called on the expertise of Cegelec, a VINCI Energies brand. Cegelec specialises in consultancy, design, engineering, installation and maintenance of tertiary/industrial buildings and infrastructure projects. Thanks to Cegelec’s optimisation of the HVAC systems, Immobel has succeeded in reducing the annual CO2 emissions generated by the Commerce 46 building by 60.6 tonnes. As a result, the building has been awarded a BREEAM Outstanding certificate.

Commerce 46, developed by property specialists Immobel, is an innovative office complex with 12 above-ground levels, 3 underground levels and a total surface area of 14,200 m². Located on the corner of Rue Belliard and Rue du Commerce in Brussels, the building offers large workspaces, an archive area, a private garden, spacious roof terraces and parking spaces for cars and bicycles. The main objective of the project was to create a building that does not use fossil fuels, in line with the growing ecological awareness in the European quarter.

Cegelec, the VINCI Energies brand, is responsible for the HVAC installations and energy monitoring of the systems. Immobel chose Cegelec following previous positive experiences. Following an initial study by the CES engineering office, Cegelec installed a 6-pipe heat pump for heating and cooling, a 4-pipe heat pump for heating and another air-to-water heat pump as a back-up solution for peak heat demand. At the same time, Cegelec installed a 600 kW variable-speed screw chiller with condenser, combined with a 750 kW cooling tower to cope with heat peaks. This solution avoids overloading the geothermal system, balances the ground temperature and meets the requirements of low-consumption, and therefore environmentally-friendly, buildings.

The building is air-conditioned with a system of radiant ceilings, providing optimum comfort thanks to an even distribution of heat or cold, notably reducing temperature variations and eliminating draughts. Occupants benefit from a stable, pleasant environment, while saving energy.

Cegelec Fire Solutions, which specialises in fire safety installations, is responsible for integrating the fire detection systems with the centralised technical management system (GTB). For its part, ITB – another VINCI Energies brand – is in charge of the power supply and the installation of photovoltaic panels. In total, all these solutions helped to save 60.6 tonnes of CO2 emissions.

Considerable technical challenges

“The biggest challenge was the limited space available in the basement to install all the HVAC technical installations. We also had to find an innovative solution for placing the cooling tower in the basement rather than outside the building or on the roof, which is often the case for such systems“, explains Ludovic Godon, Energy and Technical Manager at Cegelec Belgium.

After an in-depth study, working with experts and adjusting the control system, Cegelec was able to bring all the technical equipment together in the basement. This involved revising the functional analysis, paying particular attention to potential corrosion problems and the meticulous choice of equipment. This innovative solution is a first, both for Cegelec and at national level. It has also freed up space to install photovoltaic panels on the roof. These panels supply the heat pumps with green energy.

BREEAM Outstanding

In collaboration with CES and using the IES VE Pro software, Cegelec calculated that a basic system complying with EPB standards and used in particular for heating, cooling and lighting the offices would generate almost 110 tonnes of CO2 each year. The technical improvements made to the HVAC installations and the photovoltaic panels have reduced these emissions by 60.6 tonnes per year. Apart from the consumption of the heat pump, partially offset by the solar panels, HVAC production does not contribute to CO2 emissions. The extremely sustainable nature of the building, to which other partners have also contributed, has earned it a BREEAM Outstanding certificate.

A sustainable future

Eventually, the building will be occupied by the European Commission, for which some rental accommodation is planned. Because of the addition of meeting rooms, their lighting and the regulation required by these new developments, Cegelec has to review the hydraulic and aeraulic distribution for the heating and cooling of the new meeting rooms.

“We always take into account a reserve when sizing our installation, with a view to future extensions or ecological developments. With climate change in mind, for example, we need to prepare our buildings for more extreme situations. Our partners will also have to make adjustments in the areas of electricity and fire. The project will inspire the dynamic European quarter of Brussels and serve as a benchmark for tomorrow’s offices. We’re proud to be able to make our contribution to this project,” concludes Ludovic Godon.