How can I connect bicycle to a exhaust fan to make it work?

Question

we have a SIP(science investigatory project) and we need to make a exhaust fan work with the use of a bicycle. how can i do these?

Answer 1

The first two answers are good.

If you only need to operate the exhaust fan while pedaling the bike, the most efficient way to power the fan is through a direct mechanical connection.  Set up a fan that connects to the pedal's spocket through a direct chain drive, basically turn the fan by pedaling instead of the rear wheel.

If you need to store energy, to run the fan when you are not pedalling, the idea of setting up the bike in a stationary position and turning a generator that charges a battery used to drive an electric fan works fine too.  Note that in the conversion process from mechanical energy, to electrical energy, and back to mechanical energy when the fan is turning, will always have some efficiency losses.

Heres another thought, especially if the user is an avid biker:

Why not add a rechargeable battery and a generator to your bicycle that you drive every day? Something not extremely heavy, maybe a Lithium Ion battery pack from a laptop.  Flat enough that it could be mounted unobtrusively on the bike frame.  And can provide substantial current.

Whenever you take your bike out for a drive, you will be charging the battery.  When you get home, remove the charged battery and connect it to the fan.  

On Bad weather days you could come up with a mechanical stand for the bike, and pedal indoors.

When doing this pedaling the bike will take more energy on your part, actually, equivalent to the energy that is stored in the battery, and a little extra for the losses in the generation process.

You could have two or more batteries, so when one is being used to power the fan, you could be charging the other when out riding.  If you had a family of 4 who all like to bike, you could all be charging batteries when out riding, and potentially, depending on the power needed for the fan, keep it running constantly by switching out the various batteries.  The switching process could easily be set up for "hot swapping" the batteries, where you connect the freshly charged battery before the first is completely run out, and then remove the first for re-charging.

The added benefit here is that yes, you will be pedaling a bit harder carrying the battery and charging it while biking, and that will just be a bit more exercise for you.

Interestingly enough, you could implement an adjustable charge current regulator on your bike generator.  This would allow you to start out charging the batteries initially at a slower pace and less of an added pedalling burden, and over time, adjust it up to the full charge rate.  This would allow the biker to slowly increase the added burden, and work his way up to the full rate, and he will not even notice the extra effort.  At the same time it will be building up his pedaling endurance!

Good luck!

Answer 2

Two ways I can think of:

Place bike on a bike stand (raises the rear wheel off the floor so the bike will not move). Then try one of the following:

a. Get a DC generator available in any bike shop (used to power lights). Mount generator to rear tire. Get a DC motor of the same volts as the generator. Install the DC motor in an exhaust fan and wire to the generator. Pedaling the bike will produce the electricity via the generator to run the fan motor.

b. Use a drive mechanism such as a chain or belt attached to the rear tire via a pulley or hub. Connect the drive directly to the exhaust fan. This may be a bit more complicated than the above method.

Answer 3

the best and least expensive way is to use a chain. building the stuff to generate power, store it and then transmit it to the fan is very costly and expensive. that is deffeinatly not the way to do it. a chian is best but that is not very cool is it?

a cool way is hydraulics! more efficant, easier to understand and cheaper than electricity. you will also be the only person with one like it. everybody else will waste their time trying to generate electricity use two water pumps and two hoses. use the bike to turn the first pump. the first pump sends water to the second pump which turns the fan.  this is the best way to do it if the fan is not located near by to the bike. if you are actually going to build this, be careful, you will need to locate pumps that can build a pressure. most pumps are circulating pumps. they can not generate enough pressure to turn the second pump. pressure reservoir can also be used to store the pressurize water until it is needed.

Answer 4

you need something like recharging a battery with bicycle and then running the exhaust fan with it.