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Underwater Power Generation?
An anonymous reader writes:
"We keep seeing stories here about tidal power, and that's cool, but I don't see how it can be done without a column rising all the way to the surface. So here are the ideas I've got right now." Read on for some interesting thoughts on the subject...
"Keep in mind that the device will probably be housed in a length of 4-inch PVC or ABS pipe, and it needs about 0.5 ma at 1.5 volts:
- Surge power. Put a couple of funnels back-to-back with a CPU cooling fan-sized turbine and generator in the middle, and run the output through a rectifier and capacitor. But how reliable will those moving parts be after years underwater?
- Self-winding watch concept. Float the thing tethered to the bottom and install some sort of pendulum inside with a magnet on it, moving through a coil. The moving parts are protected, but will it be enough power?
- Yank the chain. Again, tether it, but use the varying tension on the tether to drive a dynamo of some sort. Not sure how this would work.
- Magnetohydrodynamic generator. Like the surge power thing, but using the flow of cunductive seawater through a magnetic field to generate a current. I have no idea how much power this would generate, if any, or how to deal with ion accumulation at the electrodes.
- Nukes. Anyone got a spare radioisotope thermoelectric generator? Any idea how many smoke detectors I'd need to cannibalize to get enough Americium-241?
piezo electric rods placed along the coast to capture the energy of wave motion and tidal effects. Unstable airfoils could be placed on top to "play" the rod even during relativly calm periods. In vast mumbers, They would provide two benifits: Act as bariers to coastline erosion because they would absorb the energy of coastal wave action and The generation of electricity of course.
If voting were effective, it would be illegal by now.
The currents through some channels are well known and steady. Put underwater "windmills" in the channel and sit back and collect the "juice". This is similar to sailboats that tow small electric generators or put magnets on the propeller shaft to trickle charge the batteries.
I've hit Karma 50 and gotten a Score:5, Troll... I win!
If your circuit could tolerate voltage droop, a single D-cell would run it for a few years. But voltage droop is probably annoying, so put in a few D-cells and a voltage regulator.
Alkaline batteries aren't rated to last more than 8 years or so, so use lithium batteries if you need something good for decades.
We need to know how many years this should work to give you more precise advise.
I can think of lots of ways to produce 0.75 milliwatts, just none of them will be more reliable than a lithium battery.
The idea would be to use the temperature differential (which can be significant - 10 degrees Faranheit isn't unusual) to generate current. A decent thermocouple would be able to do this without too much difficulty.
The difficulty, of course, is getting the thermocouple on either side of the thermocline. If the device can be of sufficient length (describing it as housed in a pipe suggests as much) this shouldn't be an issue. However, remaining on the thermocline could be difficult. Perhaps some sort of diaphram that would maintain position at the boundary? Tricky.
IP is just rude.
Is there any torture so subl