Stockholm's Concert hall has just been fitted with a completely new ventilation system. Hopefully, it will allow the creation of an acoustic environment that will make the building one of the best concert halls in the world. The unique diffusers that cover the rear wall of the stage do not just provide an excellent indoor climate, they also contribute to vastly improved acoustics.
The reconstruction of the Concert hall actually started in 2006. Hans Adler, who is responsible for technology and property management at the Concert hall, realised that it might be possible to claim an energy subsidy to help rebuild the failing ventilation system. The system was old (built in 1973) and wasn't at all suited to the way in which the Concert hall is used today.
When the Concert hall was inaugurated in 1926 it was intended entirely for concerts. Today it is used for events such as the Nobel Prize ceremony, weddings and wedding dinners as well as small exhibitions and large rock concerts in the blue house at Hötorget. The foyers that were previously only passages are now used for exhibitions, buffets and mingle parties, which place completely different demands on the indoor environment.
Hans Adler took contact with Lars Palmgren, who has been a technical consultant for the Concert hall during the last 15 years, and they performed a rapid investigation. The result showed that by rebuilding the ventilation system, they could reduce energy consumption by around 35 per cent.
“Anything that is done in the concert halls must take many other things into consideration. If we had only wished to improve the indoor climate, it would have affected both the acoustics and architecture negatively. Our mission was to create a really good indoor climate for many different activities, while at the same time hopefully improving the acoustics and not affecting the architecture. The building is profoundly beautiful and must remain so,” says Lars Palmgren.
Jan Nilsson from EnergoRetea is the person who created the ventilation system and who selected special diffusers from Fläkt Woods. “What we did was to create a very flexible system. In the large concert hall, the entire rear stage wall is covered by diffusers hidden behind perforated openable covers, which work extremely well visually with the old stone walls. Irrespective of what happens on the stage, if it's a violin concert with five violinists, a rock concert or a full symphony orchestra, we can create the best environment for each occasion.”
Hans Adler, Lars Palmgren and Jan Nilsson all take up the very special questions that arise in a project like this. Hans Adler formulates it very clearly: “How does one create a climate that suits ladies in shoulderless dresses, gentlemen in dress suits and the wind instruments section of an orchestra whose physical efforts compare with those of athletes? In the same place? At the same time?”
These three together have found some both unusual and creative solutions to the many differing problems. A few examples:
- Doors that are no longer used but have been left in place in the foyers are now blind doors with diffusers behind them. The fronts will be painted so that at first glance, it will not be possible to tell them from the real doors.
- The greatly increased quantities of air created new problems. How should all this air be transported away? Building new extraction channels was not acceptable. The solution was to use two stairwells that are behind the public section of the building. The stairwells are still stairwells – but also extraction channels of gigantic proportions.
The new system will provide 10 litres of air per person per second in the halls. Ten ventilation plants have been replaced and there are 360 new diffusers in the auditorium. The complete system is to be up and running by January 2009.
“We visited many concert halls around the world to find the best solution. We haven't found it anywhere, so we created it ourselves,” says Hans Adler.
|
