Renovating historic buildings sustainably while preserving their character and authenticity is often a challenge. For the renovation of Hal 9, on the corner of Karel Schurmansstraat and Werkhuizenstraat, it was clear from the outset that the city of Leuven would go for a 100% fossil-free design in any case. But the city wants to take things a step further. On top of making the building itself fossil-free, the hall will be equipped with technologies that not only power the building itself, but can also support the surrounding neighbourhood.

More solar panels than are needed for the building

One of the first steps towards an energy-efficient Hal 9 is an extensive solar panel installation on the roof. This installation will be overdimensioned, in other words larger than the building itself requires. As a result, excess green electricity can eventually either be stored in a battery for use within the hal itself during the night, or shared with other nearby users. To be able to accommodate the installation, the supporting structure of the roof will be reinforced.

District heating for the neighbourhood

An extensive BTES (Borehole Thermal Energy Storage) field will be located under the hall, which will not only provide heat and cooling for Hal 9 itself, but also has the potential to supply heat and cooling to a possible future heat network for the surrounding neighbourhood. By providing sufficient boreholes under the building now, more capacity than necessary is therefore already provided, with a fossil free future in mind. After all, once the renovation work is over, drilling holes underneath the hall is no longer an option.

In addition, the city is exploring the option of using sewage heat by extracting heat from wastewater from a nearby Aquafin collector. This collector collects wastewater from about 8,000 residents. This heat could be used to feed the heat network and balance out the BTES field.

Circular materials

In the design and material choices, the focus was on circularity and renewable materials. Where possible, construction materials are placed in such a way that they can be reused later without loss of value or functionality. Whenever possible, the city also prefers to opt for renewable materials. Non-renewable materials are - where they were deemed necessary - incorporated in the basic structure of the building, for stability reasons. However, the use of these non-renewable construction materials is partly compensated by the fact that the structure has a long lifespan.

In addition, renovating an existing building is in itself partly a sustainable choice, because by restoring the deteriorated hall and reusing it for a new function, new construction elsewhere is avoided.

The GRO sustainability meter as a guide

In order to take a systematic and structured approach to sustainability, the city has also been using the GRO sustainability meter as a guide during design.

Future-proof infrastructure

The City of Leuven is looking at this renovation project with a view to 2030, and beyond. The foundations for a sustainable heat network are being laid, solar panels are being maximised and the infrastructure is being prepared for further innovations, such as energy sharing. The challenge: turning Hal 9 into an energy hub for the neighbourhood. What now looks like a renovation could become the construction of an innovative sustainable energy hub for the city.

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