150 years ago the elevator made the skyscraper possible; buildings have been getting higher ever since. But now elevators, instead of enabling buildings to go higher, have become a limitation; they take up a lot of space, up to 40% of a building’s area. Until now, there were only three things that elevator designers had to play with: speed (too fast and people complain) cab size (too big and it takes forever to load and people feel like they are in a bus) and number (too many and it gets really expensive and takes up a lot of space). With only one or at best two cabs in a shaft, it is much like a track between cities with only one train on the whole line, hugely expensive and inefficient. And the higher they go, the heavier the cable; they are often working to move as much cable as cab. When the building sways (all do) the cable starts swaying too.
This is about to change big time. Thyssen Krupp has developed a new elevator that is much like a train running up a shaft, with a track on the wall and little cabs running up the track, each powered by its own set of linear induction motors. The cable is gone. Like a commuter train, if you miss one, there is another coming along in 15 to 30 seconds. So the cabs can be smaller, (they come more often) slower (nobody is waiting so it seems fast) but you can put as many into the shaft as will fit without running into the rear of the cab ahead.
It’s a lot like the old Paternoster elevators that used to be common in Europe, where you jump on a moving cab on one floor and jump off at the next; they were a lot of fun, but dangerous and now pretty much gone (except for this fun ride I had at Thyssen Krupp HQ). It ran at one speed, like a conventional chair lift at a ski resort. The new MULTI acts a bit like a high speed ski lift; you come to the stop and you see another chair coming up your rear end but the lift starts going again before it hits your back.
Elevator cabs go left and right as well as up and down
Then, when it gets to the top, the magic happens: the elevator cab goes sideways and down the down shaft. In fact it can go sideways anywhere; Expect to see a lot of very strange looking buildings, now that vertical shafts aren’t keeping architects from getting totally silly.
Don’t expect to see a lot of these in North America or Europe; it is really designed for very tall buildings, over 1000 feet high, with these acting as shuttle elevators serving sky lobbies at least 150 feet apart. This gives enough headway time for the next cab to sneak up your rear. Don’t expect to yell “hold that door” either; there is going to be a whole lot of re-education about how people use elevators. But then if there is another one every 15 seconds, who cares about waiting?
There are a lot of challenges ahead in making this work. Cabs have to be very light (think carbon fibre) because linear induction motors are expensive. Servicing them will be interesting; if something breaks down it’s not just one shaft and cab knocked out, it could be the majority of the elevators since the cabs are all in one shaft. Fortunately, like a train on a track, a cab can be shunted to a sideline for service.
This has serious implications for building and urban design.
There are serious building and urban design implications of this concept. Elevators no longer limit the height of buildings so those vertical cities could really be around the corner. A lot less embodied energy is wasted in making all those shafts; this system could reduce the footprint of buildings by as much 50%. Shafts and cabs are smaller, too. That smaller envelope, and not having to move all those cables as well as the elevator cabs might save a lot of energy. It will also save a lot of construction time; because conventional elevators are hung from the top of the building, they are often the last thing finished and can seriously delay opening. Here, the linear motor’s track is installed as the building goes up. Plan it right and they might be servicing occupied lower floors before the building even tops out.
It’s like a subway system on the wall.
Because the elevator runs up and down a track and can be switched from one to another, it could become part of a new kind of mass transit system, shunting cabs from building to building to higher capacity transit hub. Research Head Markus Jetter notes: “Basically, you have to imagine a metro, like the Circle Line in London, and put it on the wall. The trains, then, become carriages travelling on vertical tracks in the elevator shafts.”
(They laughed when I quoted Markus in London, and suggested he find another analogy; The Circle Line no longer runs in a circle and is notorious for breaking down all the time.)
Lloyd Alter at press conference, ThyssenKrupp/CC BY 2.0
I was surprised that ThyssenKrupp brought so many writers and journalists to Essen for the announcement of a system that is at such an early stage of development, but Markus Jetter explains that buildings take so long to get designed and built that they had to announce the system now, so that it could be designed into buildings that might not start construction for 5 years. Although there is a lot of work to be done, ThyssenKrupp is devoting three shafts in their new 800 foot tall test tower to this system and could have it running in three years.
Buildings are becoming like vertical cities, and they need a flexible transport system similar to a metro.
There are a lot of readers of this site who are skeptical about super-tall buildings and the idea of vertical cities, but the fact remains, the distances people have to travel vertically are a whole lot less than horizontal. Cities have to accommodate another 2.5 billion people in the next thirty years. Going tall can stop sprawl and keep people close to work and schools, reducing travel distance and the energy used in transportation. The real limitation has been the vertical transport system, with only one car in each shaft; it just got too expensive and inefficient and slow to go really tall.
Markus Jetter notes that “Buildings are becoming like vertical cities, and they need a flexible transport system similar to a metro. Speed alone does not solve the challenges posed by tall buildings.” In fact, it is like comparing sports car to a streetcar; it is mass transit that carries the bulk of the population most efficiently. It’s not as fast, but it scales.
ThyssenKrupp has essentially just turned mass transit on its side,and made it run vertical. This has implications that even they have not thought of; this isn’t just an incremental improvement like all the others in elevators over the last 150 years; this changes everything.
Here is a longer video explaining the elevator, and see also their new website, Urban Hub.
Lloyd Alter’s trip to the press conference in Essen, Germany, was paid for by ThyssenKrupp.