With thousands of people passing through them, trains and buses pulling in, and shops and food outlets open for business, stations are hives of activity. That makes them very energy intensive places, but what if you could harness all that activity and put it to work?
That’s the theory behind Kungsbrohuset, the new office building that has been described as the greenest building in Stockholm – itself a pretty green city. Built by Sweden’s national station operator Jernhusen, the building has Stockholm’s central subway station underneath. Above it is a hotel and an office block that houses Alstom, two newspapers, and various other businesses.
With over 200,000 people passing through the station every day, there is a lot of body heat. It needs to be actively cooled, so the heat is captured and piped up to the offices above. That accounts for a sizeable percentage of the building’s heating needs, and the rest is drawn from a ground source heat system. (In the course of drilling the deep holes for the heating system, they accidentally discovered a secret network of military tunnels under Stockholm)
In hot summers the offices need cooling, and this is done by pumping water up and through the building from a nearby lake – a much less energy intensive alternative to air conditioning.
Other environmental specifications include triple-glazing and big green switches on each floor so that the last person to leave can switch off all the lights in one go. Fibre optics channel daylight down through the building to stairwells with no windows. How people work in the building has also been considered. To encourage sustainable transport there are limited car spaces, but a generous bike parking area with showers and changing rooms. All these extras and efficiency measures were expensive, but they will pay for themselves in five to eight years, while the building is expected to last for 120.
All that’s missing, in my opinion, is a kinetic floor that generates electricity from people walking over it. I was hoping more stations would have those by now.