As architects continue to design taller and taller buildings, a certain limitation of elevators is going to become more of a problem – using traditional steel lifting cables, they can’t go farther than 500 meters (1,640 ft) in one vertical run. Any higher, and the weight of all the cable required is simply too much. Currently in the world's few buildings that are over 500 meters tall, passengers must transfer from one elevator line to another, part way up. Thanks to a new lightweight material known as UltraRope, however, elevators should now be able to travel up to one kilometer (3,281 ft) continuously.
UltraRope was created by Finnish elevator manufacturer Kone, and was unveiled this Monday in London. Instead of having the same cross-sectional shape as cable, it’s more ribbon- or tape-like in form. It’s composed of a carbon fiber core, covered in a high-friction plastic coating. An individual elevator car is lifted and lowered by multiple reels of UltraRope, that run into a hoisting machine at the top of the shaft.
According to Kone, on an elevator traveling 500 meters, UltraRope would reduce the total moving mass by up to 60 percent as compared to steel cables. That percentage would increase with the distance traveled.
This also means that even in buildings standing 500 meters or shorter, where steel cable could still be used, the use of UltraRope would result in substantial energy savings. For that same hypothetical 500-meter elevator, a 15 percent reduction in energy consumption would be realized. Increase the height to 800 meters (2,625 ft), and the claimed energy savings rise to 45 percent.
Additionally, UltraRope is said to be twice as strong as steel, plus it doesn’t require any lubrication, and it’s less sensitive to building sway – something that can cause elevators to shut down. However, there’s currently no word on how the initial cost of UltraRope and the associated machinery compares to that of steel cables.
More information is available in the video below.
Source: Kone via New Scientist
I was thinking linear motor tech,as well, but harder to energy recover as efficiently as with a counterweight. (with a counterweight the only energy used is to move the people, (and goods) not the lift itself, except for overcoming inertia and friction. )
Such a system could allow for horizontal and vertical shafts to honeycomb a building without complex cabling.
The reason cables are used is that they are the most efficient and reliable. Yes, linear motors could be used, but I think energy recuperation from descending lifts with this method would be far less efficient than using a simple counterweight in a standard cable design.
The counter weight limits the weight the motor/generator has to lift but it also limits the energy that the motor/generator has for generating electricity on the down run and there is a lot of unnecessary friction with the counter weight. Also using a tram system you can run dozens of cars in the same 2 shafts moving people at a more natural flow.