Currently lifts (elevators) use counterweight, which acts as battery, in the sense that it stores gravity energy. But it stores energy required for only one upward move of the lift. Whenever lift goes down with people in it, from top to ground, counter weight moves from ground to all the way to top, thus storing energy ( gravity-potential) in the counterweight which now resides at the top. Each downward move of the lift is energy genearting move and each upward move, an energy consuming move. Whenever lift has to be pulled up from bottom to top, this counterweight moves from top to bottom, thus moving lift upward possibly without any electricity at all or minuscale one.

What if it is a residential building and in the morning lot of people are going to ground floor. How we can store all of the energy released in all those SUCCESSIVE downward moves instead of storing just one downwerd move energy.

I suggest, a much larger counter weight, say, 20 times larger. Whenever, lift goes from top floor to bottom, the counter weight moves upward only 1/20th the regular distance.

This arrangement can store energy required for 20 upward moves (from bottom to top) of the lift.

This will require proper gearing.

This is analogous to car hydraulic jack. Small force moves through large distance to move much heavier weight through small distance.
-- VJW, Mar 25 2011

On the one hand I'm sure there's a nifty way to store energy in large office buildings to more efficiently handle the imbalance of up vs. down during rush hours, however, even if I understood what you said, I'm not sure that's it. [ ] pending English translation.
-- FlyingToaster, Mar 25 2011


Edited: I hope it is clearer.
-- VJW, Mar 25 2011


Your weight is going to move 1/20th as much, but it's still going to move up and down the same amount every time the elevator does.

What you want is the total mass x distance in the car to exactly equal mass x distance of the counterweight. The trick would be using a transmission so the mechanical advantage (that's what we call the whole car jack thing) is adjusted to match the load. Thusly: If the car weighs 1000kg, and goes up 100 m, the 10,000kg weight drops 10m. Then people get on that weigh 500 kg. The total weight going down is now 1500kg for 100m. The transmission adjusts such that weight is raised 15m. It all balances, and you've stored an extra 24.5kJ less transmission and frictional losses for use the next morning.
-- MechE, Mar 25 2011


I'm sure I've seen a hydraulic energy storage system in a lift in a Cambridge shopping centre. Rather than using a huge counterweight, it is simpler to pump water to a roof tank.
-- Twizz, Mar 25 2011


sp: 'bettery', 'downwerd,' 'genearting', 'analogus'
-- RayfordSteele, Mar 25 2011


Any links on hydraulic energy storage for lifts ?
-- VJW, Mar 27 2011


Hmm, how about you make the counterweight *the same* weight as the lift - i.e. make it capable of *countering* the weight of the lift, enabling you to install a motor that uses much less energy that it would otherwise have to?

This is how lifts currently work, which is good as it would mean you wouldn't have to change anything.

You could improve on the counterweight design, by making the weight sensitive to the weight of the people in the lift. This would enable you to install an even lighter, more cost effective motor, saving even more energy.

OR, you could collect rainfall on the roof, and then whenever the lift needs to go up, you trickle enough rain into the counterweight to make it outweigh the lift. Then, when the lift is at the desired height, you let out some of the counterweight's water, further adding to or taking from the counterweight as the day goes on.

I'm not sure how much water you'd need on any given day, but you could dig your office into the ground, and just collect surface water from a convenient aquifier.
-- zen_tom, Mar 31 2011


Or you could have a variable density counterweight. Cover the weight in a membrane and have arms that stick out and stretch it.

When the lift is full, the arms retract inwards and the density decreases, reducing the air-buoyancy and effectively making the weight heavier.

When the lift is empty they protrude to their fullest and the weight balloons outwards, the air-buoyancy giving maximum lift and effectively making the weight lighter.
-- mitxela, Mar 31 2011


Or have it heat powered! A fire at the bottom of the elevator provides the temperature gradient.

At the cold top, the balloonweight cools and contracts causing it to fall, and at the hot bottom, the balloonweight expands and wafts upwards.

This entire setup could be self-sufficient and go up and down all day like a lava lamp.
-- mitxela, Mar 31 2011



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