Light up aquarium using water wheel?

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Hi,
Is it possible to light up an aquarium bulb by the use of the filtered water hitting a water wheel?
If so, how long would it take to store enough energy to power the bulb?
Would it be safe to do this in a fish tank?
And would adding magnets somehow produce more energy?

Thanks,
Ryleigh Dundon

[deleted-249560]

Hi Ryleigh. The answer is basically no, since lighting takes a lot more energy than pumping water. In standard sort of home aquarium the air/water pump mechanism typically uses between 5 and 10 watts of power. Assuming that none is lost to heat (which is an incorrect assumption), that energy goes to moving air and water around. If you tap into that by putting a generator on the water wheel, you can harvest some percentage of the original energy input. If you were lucky enough to get back half, that's still 5 watts or less. You could run an LED flashlight from that, but that's all. Aquarium bulbs are still incandescent or fluorescent and consume a lot more power than that.

You could harvest and store the power somewhere but then you lose even more to inefficiency. Ignore that though, and figure that if you could harvest 5 watts and you want to light a 40 watt bulb, you can only light it 1/8 of the time. In a perfect world then, you could use your water wheel generator to charge up a battery and then light the lamp for 3 hours a day. In the real world you won't get anything close to that and I doubt you'll get any usable amount of power from the water wheel. You'd be much better off switching the aquarium lighting to LED (if that's even good for the fish and your plants) and just plugging that in separately. The system you're proposing is simply transferring energy through the water's motion and it's going to be much less efficient than just using the wall power directly. Adding more magnets won't help because it doesn't change the amount of power that goes in.

Howard