First, I must say that a search shows me that the general idea of capturing power fron an elevator has already been posted here, I will provide the link to that idea when I figure out how.
This version hopes to recoup a bit of the power thats been used to lift the elevator.
In taller buildings
when the transport is near the upper floors, a sensor would detect that and relay a message to the top of the elevator box where there is located a mechanical device that slides four solid strips out very close to the walls of the shaft to nearly close off all air rushing past.
At the top of the shaft is located an intake turbine that will be spun up by the vacuum as the elevator descends. When the elevator is near the lower levels, the strips will retract so not to reverse the process on the way back up.
The power might not be great, but some could be reclaimed, possibly cycled into batteries for emergency lighting systems.
Might make for a smoother ride on the way down and ease the wear and tear of other parts.