The idea of capturing the energy of people moving about is not new. It seems to me that the problem is often how to generate and store the small amount of energy thus produced.

Consider the (non-automatic) doors of public buildings such as school halls and courthouses. It would be nice to capture some of the energy needed to open these doors thousands of times a day.

It seems to me that winding a spring or lifting a counterweight is the way to go--from time to time, the spring discharges or the counterweight falls, generating energy in more convenient batches.
-- partdavid, Jul 30 2007

The Elevator Wheel The_20Elevator_20Wheel
maybe combine this with the elevator... [gtoal, Aug 02 2007]

Revolving Door Power Generator Revolving_20Door_20Power_20Generator
[Ander, Aug 04 2007]

Unexpected extra resistance might lead to a few face smashes, so pad the door slightly and put grips on the floor to avoid slippage. I'd imagine this would be easy to hook up on revolving doors, but those are sometimes powered, not the other way around.

The total power generated is most likely insignificant, even for large volumes of traffic, unfortunately. Instead use the rotational energy to power a modern sculpture garden (device for making one huge potato orbit another, anyone?) in front of the building, so the sculptures move faster when the building is in use and not at all at night. You might pump water for the sprinkler system.

Regardless of the application, I'd suggest direct mechanical connection, rather than involving electricity. Ooh, I thought of another: use the coiled-spring energy to open the automatic handicapped door! Yes, regulations are a bit socialist.
-- Ketchupybread, Jul 31 2007


Yes, Ketchupybread, I thought it probably would not be very much, so I was thinking of various in-building ways to use the mechanical energy. A sculpture garden and the handicapped door are two good suggestions.
-- partdavid, Jul 31 2007


Hook two doors up together electrically for much evil door fun.
-- Worldgineer, Jul 31 2007


I know someone has posted this before. The problem was pointed out that this would simply make the door a whole lot harder to open.
-- acurafan07, Jul 31 2007


It should open easily and then generate electricity on the in-swing.
-- 2 fries shy of a happy meal, Jul 31 2007


Yes, [2 fries]. Harder to close does seem better than harder to open.
-- globaltourniquet, Jul 31 2007


Why do you want to generate doors?
-- BJS, Jul 31 2007


Automatic door-closers already do this - they capture some of the energy expended in opening a door and use it to close the door.
-- hippo, Jul 31 2007


This would work even better using a revolving door! In some buildings those doors almost never stop turning.
-- J1, Jul 31 2007


// The problem was pointed out that this would simply make the door a whole lot harder to open. //

Well, it could be a little or a lot, depending how much energy you wanted to capture. It's up to the designer, and presumably it would be driven by studies of door-opening effort.
-- partdavid, Jul 31 2007


// It should open easily and then generate electricity on the in-swing. //

There's no difference, [2 fries]. The effort has to be expended to open it, whether the "extra" is recovered when the door is opened or closed. If the door does sufficient work in closing to recover extra energy, the same amount of work must be done to open it. You are doing the work (lifting a weight, coiling a spring) when you open it, regardless. It's just that in your scenario, the weight being lifted is the door.
-- partdavid, Jul 31 2007


Most building engineers see it as in their best interest to make doors that open with little to no effort. This seems the perfect door for your country cottage that has an exercise bike powering the TV in the living room.
-- k_sra, Jul 31 2007


//Most building engineers see it as in their best interest to make doors that open with little to no effort//

Ah, but due to buildings being generally positively pressurized, and due to doors generally swinging out for reasons of life safety, doors are generally harder to open than they could be. Otherwise air pressure would always keep them open (wasting energy).
-- Worldgineer, Aug 09 2007



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