[The testimonies: Is it CUBE or not CUBE?] Fonds Belval, a Luxembourg administrative building

2473 Last modified by the author on 01/10/2019 - 08:35
[The testimonies: Is it CUBE or not CUBE?] Fonds Belval, a Luxembourg administrative building

Here is a candidate who has a lot to teach us. This candidate, who had been in contact with our Luxembourg partner NEOBUILD, presented the project to his management during an internal meeting on technical management. Dossier validated, they embarked in the third edition of the CUBE 2020 competition! After 8 months of competition, this building saved more than 21% of energy at the end of August, and it is not finished! The excellent work on the consumption stubs will bear fruit until the end of the competition.

Semi-industrial buildings category

Gross useful floor area: 11,200 m²

Building in R+15

30 indoor parking spaces

Construction: 2009-2012

Average number of occupants: 249

Mode of occupation: Owner

Internal operator


1, avenue du Rock’n Roll, 4631 Esch-sur-Alzette


  Fonds Belval

What they did in the year

Technical aspects 

  • Optimisation of heating and cooling parameters,
  • Reflection on the need for light and switching off the lighting at the end of the day,
  • Working on the need for ventilation in laboratories.

On the Awareness side

  • Launch meeting,
  • Dialogue with department managers on new settings,
  • Posters to display the results,
  • Newsletter and specific e-mail address.

Their objectives for 2017

Occupying a building delivered in 2012, Guy Spenner, engineer in charge of the CUBE 2020 competition on the site, aimed to use CUBE this year to look at ways of improvement and implement corrective actions, with the main concern being to preserve the comfort of users.

Optimising technical management 

Through an initial analysis of the building, three classic areas of optimisation have been defined: heating/cooling, lighting and ventilation. On the last point, the building has the particularity of housing more than 2,000 m² of laboratories with an air extraction system that operated 24 hours a day. An important optimisation work was carried out, including switching to reduced mode by default (users switch to nominal mode when performing experiments), closing the valves on movable suction arms and increasing the humidity limit in agreement with the users.

On the heating side, work was carried out to optimise setpoint temperatures and operating ranges. Finally, an important reflection on lighting has been undertaken. While the switch to LED bulbs for individual lighting in offices is a fairly common action, our correspondent looked for other ways of optimising emergency lighting (BAES) in a non-permanent mode (in areas that do not receive public) or by adapting the lighting level to the brightness in traffic areas on the second day, which were previously poorly regulated. The lighting of the outdoor car park has been better controlled. Finally, the extinction of the entire site following the last security round at 10pm ensures that no area remains lit during the night.

Lesson learned: the ventilation requirements concern a volume of air to be renewed per person and not per m². By focusing on room occupancy, air exchange and indirectly the need for heating or cooling can be optimised. A reflection on the real use allows adjusting to the nearest one.

Raising awareness: Customised communication

While great efforts have been made on the technical side, the user's comfort has remained central to the optimisation process in order to maximise their acceptance. After a launch phase via a meeting with all the managers, communication was established through various channels: newsletters, posters in elevators, specific e-mail address for all questions related to the competition.

Service meetings were always an opportunity to review the building's performance.

Energy savings Fonds Belval 

Prepare the next step

During this year of the competition, fundamental issues were resolved while placing the occupant at the centre of the discussions. By working on the consumption stub, the Fonds Belval building ensures that savings will continue well beyond the competition phase. If the actions implemented are sustainable, the candidate is already working on the format that awareness will take beyond the competition period.

The successes:

  • Put the comfort of the occupant at the centre of the reflection,
  • Fundamental questions on ventilation, evacuation indicators to go beyond the usual recommendations,
  • Significant savings at no cost by working on the optimisation of existing installations,
  • Occupants who work on themes related to the environment and who find meaning in this concrete case.


The challenges still to be met: 

  • Implement this approach on other buildings,
  • Continue mobilisation beyond the competition period.


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