Circular elevators have been around for many years. Either in the form of classic “Paternosters” or as its derivatives like the planned “Hitachi multi-car circulating elevator“. These devices improved the capacity of elevator shafts in busy low buildings and are well-known to the industry. However this concept present a number of crucial disadvantages; it is relatively slow, geometrically limited and considered unsafe to install in many parts of the world.
Independent Multi-car Circular Elevators (IMCE) from the other end, is the concept where the cars move along a circulating path independently so that they don’t depend on the movement of their counter-weighting cars. The cars can ride freely on the circular path and stop without effecting the other traveling cars.
There is no limitation to the number of cars deployed on these systems as long as congestion will not form. The kinetic energy from descending cars can be distributed back to the ascending cars and so to create an equal energy cycle like with the classic counterweights.
Here are some favorable architectural designs:
Circular elevator design by Unsangdong Architects
Helical elevator design by Various Architects