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Discover the achievements of TopTech Engineering.


Discover in more detail the decisions that were made as part of the “Berlaymont – European Commission” Project and what systems were installed.



The calculations for required heat energy and power were made by considering that an inside temperature of 18°C to 24°C would need to be attained when the outside temperature was 30°C. If the outside temperature increased by 1°C over 30°C, then the inside temperature would also need to increase by the same amount.

The quality and flow rate of air renewal within the different premises was determined according to the number of occupants on these premises as well as the quality of outside air. As the front of the building required a high-performing energy-saving plan, as far as the building’s general air-conditioning was concerned, we needed to use precise state-of-the-art system solutions whilst still considering the general restrictions of the existing structure.


The boiler room is located on the roof level (14th floor). There are three gas boilers here, one of which is a condensing boiler. There are also three steam generators used to humidify the air.

The refrigeration system can be found in the building’s framework and includes four cooling machines. Two absorption refrigerators that are powered by cogeneration heat complete the facility. The cooling towers for these refrigeration systems can be found on two roof wings.

The total output for this heating system is 7,800 kW. The refrigeration system has an output of 10,000 kW.


Regarding the offices, we turned to an air-conditioning system that helps to save energy and provides maximum comfort without noise or drafts and without taking up space. Our choice was to use ceiling cooling systems. This type of ceiling system works by installing a copper coil inside the perforated sheet metal ceiling panels. The coil has fluid flowing through it and has a coating of heat insulation. Six radiant heating panels have been planned for each section, two of which (on the front facade) can both heat and cool depending on the weather conditions. To avoid drafts and cold coming in from the windows in winter, the radiant heat panels placed along the front of the building are powered by hot water. In summer, they work alongside four other panels, powered by cold water, to assist with cooling.

35m3 fresh air is pumped into the offices every hour, per section, by a comfort fan. Air-conditioning units to pump and remove air were planned for each wing and for each set of two floors. Fresh air for these units is retained through systems located on the roof where there is less air pollution. The air that is extracted from the office is reused to ventilate other rooms in the basement (stock rooms, archives, car park, etc.).

The European Commission needed each office to have windows that could be opened. It was therefore essential that in order to avoid wasting any energy and having condensation issues, these windows were fitted with an electrical shut-off that would automatically cut off air-conditioning in the office if the windows were opened.

It should be noted that an automatic adjusting device can allow the temperature in each office to be regulated automatically. This provides a 2-degree change in the temperature setting when an in-room detector signals that a room is unoccupied.


For meeting rooms and TV studios with high ceilings, the choice of air-conditioning depends on how the air is distributed.

This system works by pumping air at low speeds into the lower levels of the building at a temperature that is a few degrees lower than room temperature (2 to 5°C). The recirculated air then flows through the upper levels of the building.

By calculating the cooling capacities of the equipment, this system can differentiate between the power produced in the occupied areas and what is produced at the higher levels. The output and flow rate required is lower than what is needed by traditional air-conditioning systems. Therefore, a significant amount of energy is saved.

For other areas, such as lobby gardens, restaurants, cafes, and spaces next to newsrooms, a VAV (Variable Air Volume) system is used. The flow rate in this system is regulated via a thermostat according to the heat load inside a room. This device also saves substantial amounts of energy, as it only starts to work when the flowrate requires it to do so.

The interpretation booths that are located around the edge of the meeting rooms are ventilated using perforated ceilings. Other areas have fan coil units, and some specific rooms use individual air-conditioning units.

For areas that did not need either air-conditioning or a fan, heating was installed using static radiators or underfloor heating.


For its power supply, the building was connected at 11 kV on the public network. The high voltage cabin has 12 transformers adding up to 13,000 kVA of power. This cabin was left in its original location, in the middle of the building on the second basement level.

The low voltage switchboard room (3 x 400 V + N) was installed above the cabin (1st basement level). The supply lines lead from these switchboards to secondary distribution boards (general electric supply) and to other users. All connections are subject to the TN-S distribution system (4 wires).

To optimise the supply line features and to control short circuit currents, the systems were split up into different independent units:

  • HVAC supply systems (two units, each of 2 x 1.250 kVA)

  • systems that control lifting equipment (lifts, freight elevators, escalators) and controlling kitchens (one unit of 2 x 1.000 kVA)

  • general supply systems (lighting + low power supply, two units, each of 2 X 1.000 kVA),

  • “vital” devices and equipment (one unit of 2 x 1.000 kVA). Including firemen’s lifts, elevator recall to evacuation level, emergency lighting, hydrophore units, and smoke removal devices.


We used high-performing lighting systems which provided solutions that deliver comfort and save energy.

The level of lighting ranges from 300 to 500 lux via a dimmer. The lights are controlled automatically using light and occupancy sensors. Artificial lighting adjusts to daylight, so when the office is unoccupied, the artificial light turns off.

If the office is partitioned, the system can allow for light-circuit adjustments simply by changing the software.


Apart from the usual equipment required in an office building, we also used equipment that was aimed at saving energy and took environmental issues into account.

The drains underneath the building and rainwater were harvested to feed lavatory flushes and urinals. Rainwater was also harvested to feed the irrigation networks on the forecourt and terraced gardens.


Would you be interested in finding out more about our skills and knowledge? Get in touch with TopTech Engineering in Liedekerke to discuss your project!

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