Creating Electricity Using Fan Lighting Up LEDs

Er, why not just connect over-the-counter LED lighting to the supply that operates the fan?

You're not serious, are you? You are converting electricity into fan energy in the first place. To try to generate electricity from this is ignoring all the laws of physics. The losses are intolerable.

Just power the LED's with the electricity that you would use to drive the fan in the first place.

Think! Please!

Okay, I'll pretend there is some crazy reason you want to do this.

How about this: Glue tiny magnets to the tips of the fan blades, and place a series of small wire coils just outside the fan tips (almost, but not quite touching), so that as each magnet passes by a coil, it generates a small surge of electricity. Then connect your LEDs to the coils. You may need to re-balance the fan afterward to minimize vibration.

You'll probably need to experiment with the optimum orientation of the magnets, and the optimum size of the coils to get the right surge of current. Remember that LEDs work with a DC current input, not AC, so depending on how you wire this up you may need a rectifier. Most LEDs run off 1.5 to 3.5 VDC, using an average current in the 50 to 1000 milli-amp range, but you need to check the specs on your LEDs to know for sure.

Do as USBPORT says and the use the pulsed DC through an inverter to create usable AC to power your fan. Now, use the supply you were using for your fan to power your LED's. P.S. If this turns out to be the first workable perpetual motion fan ever invented, I want a piece of the pie!

Yeah, that should work. Then use photocells to capture the light emitted by the LEDs and store that energy in a battery.

Maybe these guys can help: http://www.fasterthanthewind.org/

You guys are really funny

I think you need to look at your question and then read the answers again and you will see that people are trying to help you in your very unusual quest.

Of course your idea will work given enough time & experimentation.

There is plenty of ways to get what you want.

You have a rotating item which can always be made to produce electrical energy.

It is part of the laws of physics ( See Flemings left and right hand rules.)

The term fan-energy is confusing.Actually wind energy can generate electricity.If you mount a turbine ventilator on the roof and connect a generator to its shaft you will get a voltage.

While that is true, and wind energy generators work that way, the reason for the original poster wanting to do this with the driver being an electrically-operated fan remains a total mystery. Why not use the electrical supply that is already present at the fan and cut out the rather lossy pneumatic coupling and the generator that it drives (rhetorical question)?

All of the good natured teasing aside, what I perceive you are thinking is that air movement is 'free", so why not use it to generate "free" lighting? Is that right?

If so, there is a big hole in this idea from the outset. Air movement from a fan is not "free". If you restrict it in any way, no matter how small, it will result in one of two things, probably both; less air movement and more energy used by the fan that is delivering the air in the first place.

So if, using your example, you have little holes in the ceiling with little fans running little LEDs, the aggregate decrease in air flow from having to push air though all those little fans will result in less air conditioning flow (assuming that's what it is) which means higher heat gain in the room air. Then someone will complain and to compensate, someone else will increase the air flow from the big fan. This will ultimately consume MORE energy than if you just plugged the LED lights into the wall, because there are a lot of other losses in the air delivery and little fan/generator system.

Net result: failure.

Keep thinking outside the box though, you never know when one idea will spawn another one that ends up being valuable.

But if you insist on pursuing this, here are some design ideas!

Hamster Powered Night Light

I think our guest is not challenging physics rules, he is trying to recover some energy from the air blower of an AC system.

As I understood from his question, as he is talking about holes in false ceiling, he want to use the air flow energy on the return duct to generate some energy he thought it is wasted to light some leds...

Yes this is feasable but with no benefits, when he isntalls his turbines to generate this small amount of energy, the pressure drop will increase on his fan and the energy consumed by the fan motor also, what he generates on the return duct he will pay on the fan supply... what he will gain is very small and never justify what he is going to invest...

one more method is possible only in kitchens having gud ventilators....

generally,because of opposite high wind pressure sumtimes....the exhAUST fan starts giving the wind blow inside the kitchen itself if not suitably placed keeping the surroundings in mind....

if a mechanical fan is placed ahead of this exhaust fan which is connected by bevel pinion nd worm wheel with an alternator the exhaust wind flow can easily rotate the outside fan nd in turn help to rotate the worm wheel and alternator.

although sounds strange but we need to calculate the actual thrust given by the fan using its blade angles and the rpm with which it is rotating.

can sumone please suggest the formule which we may need to use while calculating the force exerted by th fan at a particular rpm.