Never before in my life have I encountered revolving doors so often as in Germany, and every time I have to use one, I wonder what’s exactly the point.
Any ideas? The only think I can think of is that they slow down people on purpose, for crowd control.
Likely also for energy efficiency, but then the double doors system that I’m use to seems more efficient and probably cheaper than revolving doors.
It’s not a great photo, but basically you have two doors (manual, automatic, or slide) in a series, with an “airlock” space between. You open the outside door, step in the space, the outside door closes behind you, then you open the inside door and step into the building.
Perhaps because I’m far more used to them, they seem more efficient to me.
PS. This system is used in Germany too, but in very few spaces. I’ve seen it mostly in restaurants.