Air Temp Nitinol

[gadgetmall]

I haven't actually held or used one of those Nitinol Thermobile "toys" but somehow they just don't look as though one could develop much torque or power - like maybe you could bring it to a halt just by resting a finger on one of the wheels.

For example, in this YouTube video of a Thermobile type FAN:

http://www.youtube.com/watch?v=mlxrOHD49ZQ

OK, it turns the little fan, but the guy can stop it to change the direction of rotation, apparently quite easily, just by putting his finger in the way of the fan blade and pushing it in the other direction. Is this a deception ? Is it just because the wheels are made of plastic and not conducting much heat ? Somehow it doesn't look like 50 tons / square inch of force. Why no videos of this stuff actually generating even a little power. Like this "Drinking Bird" toy:

http://www.youtube.com/watch?v=Rq3K6Ma0wIU

Now that's impressive. At least it is shown to be generating some kind of meter-able energy. I would like to see something like that with a Nitinol Thermobile.

On the other hand, if Nitinol has been measured to have 50 TONS of force or pressure per square inch, what would be the force of a .020 wire ? Like 1 ton or something ? 

Has anyone ever tried attaching a small Permanent Magnet DC Motor/generator to one of these Thermobiles to see if, or how much electricity it could generate ? It seems like this would be an easy enough experiment to try.

Anyway, how about an Air-Temperature Nitinol Irrigation pump for third world farmers.

You could probably get a grant. It seems like all the nifty "appropriate technology" stuff is going overseas to some desert country somewhere.

Just set the engine over any body of water that is a few degrees cooler than the air and it will run from the temperature differential. No need for burning all that valuable cow dung needed for heating and cooking to run a Stirling Engine or something. It should work best when it is most needed; (when the air is hot and dry and the fields need irrigating).

Have you tried running your modified air-temperature Thermobile with some COOL tap water. Not ice water but just water relatively cooler than air, with a temperature differential similar to what it would be between any body of standing water or well water and the air ?

Hi . Tom . there is a Build for 1hp out there . I will have to dig through a bunch of ebooks to find it .

I don't need torque at all . All i want is to Spin Magnets on a small flywheel . I am Using air core coils so there is no cog at all .

O yes cold well water here @ 44f .water on the other end just makes it spin faster   . I played with it this morning outside and it was 46 degrees . warmed it in my hands (brass pulley) and it took off.

I am actually trying some various methods of annealing that other wires i have besides the good stuff(i call it) . so far that other wires on ebay suck . it takes below zero to make it soft , it pretty well stays springy even in cold water so don't waste you money on anything that says "Magic tricks wire" it don't work . looks like any wire kelloggs is selling needs freeze spray or liquid nitrogen to get soft. his air temp wire is just that . it stays stiff as steel in 33f and above  Air.. His body temp stay stiff also at 35f and above . useless .He sells rods also that are .20 dia and 8 inches long for 20 bucks . you need freeze spray for them too.

The 50 foot roll that  are selling on ebay   0.016 are stiff as hell too but  i can get it  to bend in ice water but just as soon as it leaves the water it's springy so it might have some winter value to me..

Now the Good Stuff 0.020 from my seller can be tuned anywhere . it can be soft @74f and below and i can bend it and warm it a bit with my hand and it springs . Wide ranges after tuning . I am glad i got a lot of it before it's gone .

Also the Dental thermal wires (rectangle) 0.21 x .0.025 are excellent . I snagged 4 bags of 10 per pak for 6 bucks . they are pure medical nitinol and can be bent in air below 74 and spring right back to shape in 70 f and above . perfect U shape every time .

As far as power just single straight pieces about 1 1/2 inch provide mass move power especially on lever type motors . i have seen some easy designs that just flip and flop and turn a flywheel and a couple that just move a lever up and down . so a one inch piece when set up in that condition can move 30 lbs. 30 inches with the phase change . Also forgot to mention that this wire is also called Flexinol . It has the ability not only to spring back to a set shape but a straight piece of it with hooks on the ends of this wire expands when cold and contracts when hot so it will lift up heavy objects pulling them up with  just the phase change with the weight of the object on the end with one strand . Up and down . about 8 percent of the length of your strand.

Now that don't sound like much but when i make a one inch spring i make it with about 12-14 inches of nitinol.
that spring can be stretched out cool about 8 inches without damaging its shape and it will pull up a pound or so back to the spring position when warmed back up to room temps.  .

ok gone playing some more

gadget

[gadgetmall]

if the dunking bird put out 1 ua and cost 5 dollars each he needs 1000 birds to make 1 milliamp.

5 dollars of Nitinol can spin a wheel of magnets and light lights and charge batteries .

I am working on it . I already see wheels turning ..

[Mark69]

Excellent work Gadget, looking forward to your progress 

[moflint]

Hi,

This is my first post so I might have missed a previous mention of this but... maybe the best way of getting work out of NiTI is Elastocaloric Cooling, ie, putting the stuff under stress and using the difference in heat (condense) and cold (expand) to run a heat pump.

The following paper in Applied Physics Letters details an available COP of around 11 (eleven). Here is the link:

http://apl.aip.org/resource/1/applab/v101/i7/p073904_s1?bypassSSO=1

I just clicked on PDF download and got the whole thing.

[Tom Booth]

Hi,

This is my first post so I might have missed a previous mention of this but... maybe the best way of getting work out of NiTI is Elastocaloric Cooling, ie, putting the stuff under stress and using the difference in heat (condense) and cold (expand) to run a heat pump.

The following paper in Applied Physics Letters details an available COP of around 11 (eleven). Here is the link:

http://apl.aip.org/resource/1/applab/v101/i7/p073904_s1?bypassSSO=1

I just clicked on PDF download and got the whole thing.

It looks like that article was just published a few months ago this year. Very interesting. So the idea of using Nitinol in a refrigeration cycle has already been explored, with apparently very promising results.

It also seems, according to this article, that the stressed Nitinol does cool down to ambient/room air temperature eventually, though this takes several minutes.