Tide power generator... need ideas

[beaufort-fj60]

I'm helping someone coble together a tide power generator for a "fish camp". The plan is to lower the generator down during the outgoing tide. There is a large propeller that will rotate pulleys to a generator. that is one pulley on the shaft of the propeller, one pulley on the joint, and one pulley at the alternator. For a visual think of the electric trolling motor. The alternator will charge a battery.

First question, is there an alternator that will work in low rmp? will the alternator need to be geared to get up to rpm?

second question, do you think a gm one wire is the best choice of alternator?

any comments appreciated.

 

[FJ40_owner]

How many Watts does the end user require? AC or DC?

Why not invest in a quality solar panel, charge controller, battery and sine wave inverter?

No Rube-Goldberg effect.

 

[beaufort-fj60]

How many Watts does the end user require? AC or DC?

Why not invest in a quality solar panel, charge controller, battery and sine wave inverter?

No Rube-Goldberg effect.

he said he wanted 12v power. I think his goal was to run some lights off the batteries. There already are a few solar panel on the dock's roof that run one light. I don't think he's to happy with the solar panels performance.

 

[FJ40_owner]

he said he wanted 12v power. I think his goal was to run some lights off the batteries. There already are a few solar panel on the dock's roof that run one light. I don't think he's to happy with the solar panels performance.

Many thing affect Photovoltaic performance. Proper orientation to the sun, panel cleanliness and panel temperature.

Other issues are voltage drop from the panel to the load. Always upsize your wire.
Connections need to be well made up and free of corrosion.

And if using only 12 volts convert lighting loads to LED.

And select the proper charge controller Algorithm for the proper battery.

 

[chet]

do some searching for windmills the generators they use kick in at low RPM and some can be made from DC motors. I cobbled together a windmill and a pulley system to a GM alt I had for an experiment for our cabin and it didn't work too well. to get the RPM I needed the drag from the pulleys was too much unless it was really windy. It may work better in the tide though. more force. I would leave the prop in the water to get the in and out tides. Does he have a channel to put it in?

 

[Fast Eddy]

The reason there's not more of these in use in the world is that it's hard to find a tide that moves fast enough in a place where you can place a large enough prop.

In an 8kt current you're going to need a 20' prop to light a light bulb. (Guessing...) Easy enough to test off the side of a boat.

Ocean? Are there waves or surge? A fixed bouy that spun a flywheel as the surge pulled it up and down could work.

 

[fsusteve]

yeah I don't see the current running fast enough consistently or convienently. It's a nice idea mr wizard but tell him to bring some gas to the camp.

 

[SINCITY100]

It sounds like FJ40 knows his stuff when it comes to solar power

I like the idea of generating power from tidal changes, but...

For general lighting and to occasionally run/charge 12-110 volt accessories, a pair of (80watt+) solar panels, an inexpensive charge controller and a set of good batteries should be able to supply more than enough power. It would be much more reliable than a TG too.

With 6-8 hours of decent sunlight daily... Using a 50w panel, a single 24-series 12v battery and an inexpensive 500 watt inverter I can illuminate a large campsite as bright as day , usually for as many days or weeks as I want to.

I use 110v CF bulbs in the 40-75 watt range in conjunction with a small inverter. The CF bulbs use so little energy that I can substantially extend my nightly hours of usage compared to using standard incandescent bulbs. IMO, the slight power "loss" from the inverter is minimal compared to the CF bulbs` increase in available light ( compared to many LEDs or low voltage fluorescents ) .

If the current solar set-up isnt working very well , my guess is that it just needs to be tweaked a little bit in order to supply more power (and thus more light).

 

[beaufort-fj60]

yeah I don't see the current running fast enough consistently or convienently. It's a nice idea mr wizard but tell him to bring some gas to the camp.

the tide rips through this creek. It's a pinch point with a humongous tidal flat behind it.

 

[beaufort-fj60]

I'll take a look at the solar panels next time I'm out there. I'm not sure which ones they are of if he even has a charge controller or a battery and sine wave inverter

 

[fsusteve]

the tide rips through this creek. It's a pinch point with a humongous tidal flat behind it.

ok if that's the case, what about a paddle wheel? Got to be easy to build and mills used them for years..

 

[beaufort-fj60]

I tried selling the paddle wheel idea, but the guy is hell bent on a prop. He picked up a 24" aluminum 4 blade high pitch prop.. not sure what its from but I don't think it will work well.

 

[fsusteve]

that's a big ass prop froma big ass motor, make a paddlewheel out of plywood it'll work.

 

[Fast Eddy]

He picked up a 24" aluminum 4 blade high pitch prop.. not sure what its from but I don't think it will work well.

That's a big-ass prop. It might turn an alternator with enough current. You're going to need some gears or belt-drive reduction to get enough RPMs.

It would be damn cool if it works.

 

[sparkplug]

Like mentioned above, I don't think the prop will work. Has he thought about micro-hydro with a turbine? I think the turbine would be the most efficient. But again, the paddle wheel is a good cheap way too.

 

[C6H12O6]

The prop idea is going to be very tough. OSU and U of O here in Oregon are working on tide power, as well as some power companies down in Cali. The props needed are ginormous and they need lots and lots of them to do much. The scale of your project would probably be a bit smaller, but it isn't very efficient. Also, if you fill up a tidal river feeding water to a floodplain with a big propeller, expect enviro-troubles when you start chopping marine life up in the prop.

If you have a bobbing tide to work with, you might play with a permanent magnet linear generator. OSU is working on building buoys with the generators (like the shake flashlights) to pass the magnets over a generator coil everytime the buoy goes up and down. Very cool, but very cutting edge and also not all that efficient yet.

 

[Duane]

I saw an acreage owner a couple summers ago that had a creek running from the back of their property down to a lake. They had a screened catch pool with an adjustable gate to allow a certain volume of water down a pipe quite a ways down to a water turbine sheaved with a drive belt to an old industrial generator which produced power for his whole farm.

I wouldn't think an automotive GM alternator would be the best choice as it would need to be spun in the hundreds of rpm. It's all about the shaft speed, number of magnets/poles and the number of windings. The less poles and windings the faster the shaft speed needed. Not sure where to source a low rpm generator.

I can think of lots of hazards of a 2 foot prop spinning away. i would perhaps create a reservoir from the tide, screen the water and control the amount and perhaps house/enclose this prop into a pipe with the drive shaft coming out of a seal with a sheave attached to adapt to a proper speed for the generator.

I tend to think the non mechanical solution of solar being the preference and generally less cash to setup and maintain especially for a smaller load such as just lighting.

We set this sort of thing up for lots of sites with a low power requirement. A solar panel, a voltage regulator, a couple 12 volt batteries designed for cycling and then 12volt dc lighting or loads. If you need more generation or capacity you add panels and batteries as required. Lots of interest in LED lighting and the lower power consumption. Having to supply ac loads and using an inverter just adds cost and complexity especially where the load is close to the source.
just my 2 cents