Office building "Souverain 25"

Client: Cofinimmo
Advisors: Aluminium Centrum (study stability joinery) 
Location: Oudergem 
Timing: 2012 – 2013 
Status: realized

Technical renovaton support I Energetic renovations

Feasibility examination for an energy renovation of the office building
"Souverain 25", located in Oudergem.

The study investigated the feasibility of a thorough façade renovation to make the office building passive. This study only focused on the building envelope. In parallel with our research, another study was held on the optimization of the technical installations based on dynamic simulations of the energy consumption.

The objective of this sub-study was to define the actions to level of the façade detailing so that the building would achieve a K16 insulation quality. We were asked to work out different scenarios ranging from a visually dramatic façade renovation to a renovation in which the façade aspect could be fully preserved. The report served as a tool for discussions with the Building Heritage Agency. An estimate for the construction costs of the various façade scenarios was also requested.

In addition to investigating potential thermal optimisations, we were also asked to conduct a study on the solar heat burdens and daylight usage in order to determine a sun protection strategy and choice of glass.

Building envelope
The largest part of the investigation was a very thorough analysis of the present building envelope through examining the as-built file, tours on site, dismantling and soundings. The support structure of Corten steel and concrete is located on the outside. The impact of perforating this support structure through the building envelope was investigated by thermographic recordings.

Furthermore, the joinery designed by Chamebel was thoroughly investigated: thermal insulation value, structural support capacity of the joinery for the application of triple glazing by the Aluminium Centre.

The total K-level of the current situation was K93. So, the façade needed to be 82% more thermal efficient after the renovation.

Within the predefined scenarios, we examined the possibilities to thermally optimize each of the building envelopes. TRISCO-software has been an important tool to resolve the thermal bridges caused by the external support structure. Principle-detail drawings were made of the scenarios to visualize the complex and calculated matters.

Due to the higher quality insulation and air-tightness of the building envelope after the renovation, the energy consumption for heating will be reduced, but the cooling season will be extended, thus increasing the cooling-costs significantly. A correct choice of glass with sufficient sun shielding characteristics is therefore important. By means of SunEye 210 (Solmetric), the shading of the exterior support structure on the façade was mapped on site. For different types of glass, the cooling load, passive solar gains and economies for artificial lighting were analysed. Based on this, it was advised not to choose too much sun-shielding glass, but rather glass with a good ratio of daylight to reflective glass. We did not recommend a glass type with the same golden glass aspect.

Our study showed that a K16 insulation quality was not feasible within the specified scenarios. But, even in the most conservative scenario in which the aspect remained completely untouched, a K28 was feasible.

Team BB: ir. arch. Katrien Van Goethem, ing. Martijn Vyncke