Author Topic: Windscreen wiper for Wave energy  (Read 6079 times)

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O_Walker

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Windscreen wiper for Wave energy
« on: March 22, 2016, 10:48:32 PM »
Hello,
I'm trying to make a wave energy generator, there seems to be lots of power in those waves... just think how easily they can rock a whole boat when you're standing on the side, lifting your body up and down every second or so.

I recently had the idea to use either a car window or wiper motor and connect it directly to a boat, because they are strongly geared, and already have a linear motion.

I understand from reading up on it that electric windows have systems built into them to (logically enough) stop them being moveable by an outside forcce (i.e pushing against them).

But I was hoping a windscreen wiper, with a diode (sadly I don't know which one, I guess I'll ask in the shop), should create electricity if I push against it - turning the motor built into it?

What do you think people, could it work? Are any windscreen wiper better than others for this? I am in Japan, so if you're making suggestions, try to talk in general terms and not US/European car companies (or of course Japanese car companies if you know!). 

Thank you!

frackers

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Re: Windscreen wiper for Wave energy
« Reply #1 on: March 23, 2016, 02:02:59 AM »
Most wiper motors use a worm drive which has a very high ratio and really only works as a speed reducing gear - it is very inefficient the other way. Also the backwards and forwards motion of a wiper is from a crank on a wheel which will only allow it to turn half a turn before it stops. Best thing is to find a local scrap yard, pick up a couple for a few dollars and experiment with moving them by hand!

Without the crank (just geared down) they are very good at driving a threaded rod to open and close the windows on a greenhouse ;)
Robin Down Under (Or Are You Up Over)

electrondady1

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Re: Windscreen wiper for Wave energy
« Reply #2 on: March 23, 2016, 05:37:40 AM »
i live near the water  so i know what your talking about . i always thought something that worked along the lines of a small motor pull starter would work .  a float to lift it up on the wave,  but a spring to return it to position when the wave passes.


Bruce S

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Re: Windscreen wiper for Wave energy
« Reply #3 on: March 23, 2016, 07:16:09 AM »
O_Walker;
Welcome aboard!
There was somewhere on this forum a person who was working on a wave device.
I've actually seen in the tech-forums where some are forsale and seem to work pretty good too.
I agree with Frackers, the window motors will be geared for speed reduction. grab a few from the local you-pull places and have a look see.
Of the ones I've replaced in autos, vans, etc they are 12Vdc and that's a pretty universal voltage or autos.
Cheers
Bruce S
A kind word often goes unsaid BUT never goes unheard

Mary B

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Re: Windscreen wiper for Wave energy
« Reply #4 on: March 23, 2016, 02:55:34 PM »
I would think a linear motor would be a better choice. Like an axial flux made in a long line instead of round, use diodes to send the power pulses the right direction...

O_Walker

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Re: Windscreen wiper for Wave energy
« Reply #5 on: March 23, 2016, 09:33:15 PM »
Thanks frackers, electrondady Bruce and Mary,
It's good to have some ears out there.

Yesterday I bought a wiper motor complete with wipers, checked it worked, and visited some harbour spots.

I managed to move the wiper once when mounted, but it didn't seem to want to udge after that.

The hrabour has an interesting feature - a floating pier. This bobs up and down, and handily has rubber wheels keeping the pier in place in relation to the post into the seabed. This means I have a nice vertical motion if I want, and also a (more inconsistent) rotational motion. This is of course not fast, moving up and down just 14 times per minute (around 15 cm each time, so double that if power is produced in both directions). Although it's a very small distance, the power is essentially limitless - whatever I attach to it will give way before before it is hindered from moving the whole pier.

I still want to try with the wiper motor... maybe I'll need a big capacitor to store some of the energy before transfering it to a battery or device?

And I'd like to have a go with this pier and wheel, either using the wheel, or the pier post.

I don't know where to get a linear motor, but that's clearly a good idea.

MattM

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Re: Windscreen wiper for Wave energy
« Reply #6 on: March 24, 2016, 01:43:42 AM »
A scotch yoke would give you better results with a locking cog lever to create unidirectional movements on the crank.

https://www.youtube.com/watch?v=_K4PSV4MO70

MattM

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Re: Windscreen wiper for Wave energy
« Reply #7 on: March 24, 2016, 01:59:48 AM »

DamonHD

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Re: Windscreen wiper for Wave energy
« Reply #8 on: March 24, 2016, 03:02:27 AM »
I think it's worth bearing in mind that extracting energy from waves has been about the least successful commercially of marine energy sources, coming well after tidsl / tidal stream and wind.

But take a look at the sort of work going on here:

http://www.emec.org.uk/research/

Rgds

Damon

O_Walker

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Re: Windscreen wiper for Wave energy
« Reply #9 on: March 24, 2016, 09:08:50 PM »
Hi all,
It's really interesting that wave energy has been so unsucessful commercially. I think lack of investment is the main reason. Looking at some of the devices that are being developed around the world, they are really different, and some so primitive when you think what technology we have. And there are many stories of them going bust too... if only nuclear went bust!

Anyway, the wiper did generate a little electricity, but seems to block at a certain angle.

I bought some small motors with inbuilt gearing, and developed a little rig to hopefully get the boat's swaying to power it... it's a tiny charge though. The motors have an rpm of around 35. I also need to learn about capacitors and bdrige rectifiers, because at the moment it's only getting power on the up wave!

I really ideally need a much more powerful motor, with a slower rpm still.

electrondady1

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Re: Windscreen wiper for Wave energy
« Reply #10 on: March 30, 2016, 08:54:32 PM »

Valalvax

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Re: Windscreen wiper for Wave energy
« Reply #11 on: May 02, 2016, 06:06:14 PM »
i live near the water  so i know what your talking about . i always thought something that worked along the lines of a small motor pull starter would work .  a float to lift it up on the wave,  but a spring to return it to position when the wave passes.

Why not just use a heavy float? I mean boats are heavy but float due to buoyancy. Water moves it up, and gravity moves it down, no spring to replace/wear out

Unless I'm misunderstanding what you're thinking of

O_Walker

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Re: Windscreen wiper for Wave energy
« Reply #12 on: May 03, 2016, 04:58:48 AM »
Thanks for the video tip with the TV show, that's great to see.

I don't want to use a heavy float because I then have to build a heavy float, and it needs space. Boats already exist, so it's a kind of parasite generator.

Thanks for your thoughts though.

tanner0441

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Re: Windscreen wiper for Wave energy
« Reply #13 on: May 03, 2016, 02:53:06 PM »
Hi

As a point of reference 1 cubic foot of air has a buoyancy factor of 70 pounds. ie. It will take 70 pounds of downward force to push 1 cubic foot of air below the surface. That is at atmospheric pressure. Pumping 2 cu/ft of air into a 1 cu/ft box will not give you any more buoyancy.

It may help to do dry runs on your project without getting your feet wet.

Brian.

electrondady1

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Re: Windscreen wiper for Wave energy
« Reply #14 on: May 03, 2016, 07:00:27 PM »

 i like  the use of that "special'' blade ,  it allows the oscillating water movement to become a constant rotating motion.
the faster you spin an alternator the more electricity it produces.
you need to design something like a bellows on the dock that is powered by the boats movements
but you better batten down .
or you will need the power  to bail out the boat.
the alternative is to have the bellows on board and you can get energy where ever you dock or anchor.
 

 
 

george65

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Re: Windscreen wiper for Wave energy
« Reply #15 on: August 22, 2016, 03:04:37 AM »

Do you have an actual location to install this or are you just theorising at this stage?
The application will depend on the best sort of generator to use.

If you were going to attach this to a floating which was lineal motion, then I'd be using that with a linear generator. Could be as simple as securing coils to the pier and having the magnets moving up and down on the pontoon. Although the travel would be short, the area you have to work with would be relatively huge in terms of space for windings so I can't see why you couldn't get decent power output.

As for the rocking motion of a boat, that's going to be lineal and axial as I see it and you are also going to have to deal with different angles from the rising and falling tide.

And the big question would be how much power you want?
If you just want to see if you can do it, fine but bear in mind other than the ability and curiosity factor, it may be pointless.
You could well find while you can make power, the power you make per watt may be pointless from the POV that you could make more with a simple and cheaper wind turbine or solar panels. They would also likely have a lot less maintenance issues.

That eco warrior show annoys the guts out of me.  They are supposed to be saving the planet yet their stupid, and they are invariably, stupid, creations always use more resources and cost more than they could ever return over their short lifetime.
On that wave power one I see them rolling out a great long cable back to the van. I can't see them getting away with that in any first world country nor having that box sitting by the breakwater.  The local authorities would be all over them the very next day.

They WOULD have done infinitely better from a cost let alone practicability POV with solar panels and batteries or even a small wind turbine as it was evident where they were had no shortage of that resource. 

Ability to do something is one thing. The practicabilities and cost efficiency's are something else.