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Earlier quoted context omitted.
The space isn't wasted if it's used to transport people, though.
In an n floor building, nobody is being transported in n-1 floors.
Plus, in this system all the elevators are centrally scheduled and therefore there won't be any concern about human drivers fouling up the system :)
The big benefit is that you get more than one elevator per shaft. For skyscrapers the amount of floor space wasted by elevators grows exponentially by the number of floors. Say you have a 5 story building that needs a one shaft elevator. 5 floors tiles 100 sqft per floor is 500 sqft of wasted shaft space. Then say you have a 10 story building that needs two shafts. Now you are wasting 10 floors times two shafts or 2,…
Sorry to sound stupid, but how is that exponential? Isn't it O(mn) where m = number of floors and n = number of shafts? EDIT: Unless there's some dependence between m and n, like if taller buildings always need more shafts or something.
It's really rough in convention center hotels when a huge convention comes to town a lot of the time it's practically impossible to get an elevator down from the middle floors because it's already full from the floors above you.
My ideal elevator would accelerate at a pleasant 4 m/s^2 and have a jerk not exceeding 4 m/s^3. It would have doors that close instantly when the doorway is clear, and start right away. That would be able to take me up a 100 yard high building in 11 seconds. Why can't real elevators be like that? Why must the doors move slowly, and wait for 5 seconds before even starting moving? Why does the elevator reach a sluggish…
Doors have to close slowly for safety. There's a limit on how much kinetic energy (7 foot-pounds, from memory) can be in a closing door. Opening can be much faster, and on high-speed elevators, it usually is.
At the destination floor, there's often a delay for precise leveling. Position feedback for leveling is just limit switches until you get to the really fancy high-speed elevators, so it works by shifting to slow speed and inching until the switch trips. Fancier elevators used analog optical systems and inductive systems that gave an analog signal of leveling error. Here's a modern elevator position sensor, with a bar code strip running the height of the shaft.[1]
Precision position and speed control of large motors was really hard in the 20th century.
[1] https://www.cedes.com/documents/produkte/Broschueren/108783e...
Earlier quoted context omitted.
Sorry to sound stupid, but how is that exponential? Isn't it O(mn) where m = number of floors and n = number of shafts? EDIT: Unless there's some dependence between m and n, like if taller buildings always need more shafts or something.
> like if taller buildings always need more shafts or something The dependence is on keeping wait times reasonable. Taller buildings mean each shaft's elevator spends more time travelling, i.e. less time being available.
Am I the only one who noticed that the first elevator shown in the video, while the narrator discussed the birth of the elevator in 1854, is gear-based and hence rope-free?!
That's Otis's original safety elevator, and it was a rope system. The innovation was that it had a mechanism to stop it if the rope broke.
Earlier quoted context omitted.
> like if taller buildings always need more shafts or something The dependence is on keeping wait times reasonable. Taller buildings mean each shaft's elevator spends more time travelling, i.e. less time being available.
At this point you start doing locals (multiple elevators per shaft traversing only a subset of the entire building) and express (elevators skipping floors, usually between ground floors and various "sky lobbies" at 30~40 floors interval).
The big benefit is that you get more than one elevator per shaft. For skyscrapers the amount of floor space wasted by elevators grows exponentially by the number of floors. Say you have a 5 story building that needs a one shaft elevator. 5 floors tiles 100 sqft per floor is 500 sqft of wasted shaft space. Then say you have a 10 story building that needs two shafts. Now you are wasting 10 floors times two shafts or 2,…
Schedulers for Multi must be fun - I'm sure they must have employed a whole research group for solving this problem. Scheduling simple elavator systems is still a problem nowadays, this one? It's so much harder.
This will be how we build towers twice as tall as existing megatowers. As beautifully explained by xkcd[0], "If your building has lots of floors, you need lots of different elevators, since there would be so many people trying to come and go the same time. If you make a building too tall, the whole thing gets taken up by elevators and there's no space for regular rooms." But if one elevator shaft can have multiple in…
The car motion is not independent and it's hard to use the capacity well. Consider the morning rush in a big office tower when everyone starts on the ground floor. You can only use the bottom car to move these people. You need a sideways dimension of movement to avoid this problem.
you mean like the elevator system being discussed here?