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Author Topic: Air Temp Nitinol  (Read 206142 times)

Paul-R

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Re: Air Temp Nitinol
« Reply #90 on: September 23, 2012, 03:44:54 PM »
hello Paul-R . the Volts will drop but the current is still there.
The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?

Cherryman

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Re: Air Temp Nitinol
« Reply #91 on: September 23, 2012, 03:47:41 PM »
The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?


I've heard that a lot of those hand powered (crank, shake etc ) flash lights use capacitors instead of batteries, so you might want to look in those circuits. As they also need a slow discharge.


example:



http://www.modernoutpost.com/shop/flashlights/335-lightstorm-cl1.html

gadgetmall

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Re: Air Temp Nitinol
« Reply #92 on: September 23, 2012, 06:27:19 PM »
The snag is that many devices need a constant voltage. Is there a circuit that one could
hang off it to supply a steady voltage as the power is drawn?

Hi . paul . sure there is solid state regulators that can do that . I have build a few for lasers because the need 4.5 volts . Most every circuit i have designed or replicated is 1.5 - 1.2 volts  They run constant down to less than .3 volts so the Bcaps serve me well with just a pot in series . My point was they can Anneal Nitinol Wires in a controlled way because the resistance in that wire is almost as high as nichrome wire. takes a lot of current to heat them up properly and evenly . You can't do that with a torch and an oven is only good for shaping the Niti. you can shape it in an oven but the phase change will be wide .I need very narrow for Air temp Phases .

Tom Booth

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Re: Air Temp Nitinol
« Reply #93 on: September 23, 2012, 08:04:21 PM »
Thanks for the info on the capacitors, I wasn't aware of these advances.

I'm actually 100% off the grid using photovoltaic panels and  replacing worn out deep-cycle batteries every so many years has been something of a nuisance and expense.

Getting back to the hot and cold thing. I thought of one possible explanation.

Perhaps when bent, the Nitinol takes on a characteristic something like aluminum. That is, it becomes a heat "reflector" of sorts, quickly absorbing and releasing ones own body heat when touched. I've sometimes felt what seemed like heat coming off some aluminized insulation but of course it was only reflecting heat from my hand.

When straightened perhaps it becomes more of a heat conductor drawing heat away and so feels cold.

Just a guess. On the other hand you say that this is more than subjective. i.e. causes color changes when a liquid crystal strip thermometer is applied.

At any rate it seems strange that you say heat is felt but not conducted to your hand. I'm not sure what that means really, as the sensation or feeling of heat is (usually) a result of actual heat exchange, except something like a chemical heat, hot pepper sauce or something.

I'm wondering if any extensive research has been done to figure out what exactly is going on, how long does the effect last. (How long does it stay hot after being bent) etc.

If it continues giving off heat for a long time (or seemingly indefinitely) does it then get that much colder when released the longer it has been previously stressed ?

Also I'm wondering if it isn't doing something like conducting heat when bent.

That is, I've only seen this in the video where someone is actually holding and bending the Nitinol with their hands. Theoretically, I suppose the heat could be absorbed at the ends where it is being held in the hand and the heat released at the point where it is bent. That would make it a sort of heat-pump when stressed.

If that were the case it would probably do the same thing even if mechanically bent - absorbing heat from the environment at the unstressed ends and releasing it at the point where stressed. Again that would make it a kind of heat-pump with no moving parts. Even if it were only transporting or conducting heat instead of actually generating heat, that seems incredible enough in itself.

If you (or anyone) know of or come across any additional information/research on this please let me know. It kind of begs some sort of explanation.

gadgetmall

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Re: Air Temp Nitinol
« Reply #94 on: September 24, 2012, 01:22:06 PM »
there is a nitinol pdf that was on the Internet and can't find it any more. maybe fbi took it out . they seem to want to control the Internet now.

I really think once you feel the power and strength of the work it can do you will understand that that heat cold thing to me interesting but not useful as a motor . loops of this stuff on the  right size pulleys(small) look like the key and lever motors using small pieces straight on a spoke looks promising . It is cooler now and my nitinol is soft outside so i will be testing  a small model out side in a small hole with water bowl insulated from the air  and  brass pulley above ground to test the winter cycle and see if the ground will give me heat instead of cold . if it does give me that 25 30 degree difference the phase change will happen and the flywheel should turn .The flywheel will have magnets on it and capture the field in an air core pickup  and charge a B-cap. Hopefully that b-cap can charge and switch on lights outside .

gadgetmall

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Re: Air Temp Nitinol
« Reply #95 on: September 25, 2012, 02:23:33 PM »
Notes:The successful development of
commercial heat engines would challenge
at least three competing energy systems in
which considerable money and effort have
long been invested: photovoltaic cells,
solar-power towers and organic-fluid
Rankine turbines. All three systems could
be rendered obsolete by Nitinol heat
engines. According to the latest Navy
figures, a Nitinol heat engine could convert
energy for a mere six percent of the current
cost of photovoltaic conversion. And while
photovoltaic cells are fragile, Nitinol is
tough, and it gets tougher. “Nitinol never
wears out,” says McMillan. “It just keeps
getting better and better.

Liquid Crystal paint supplier http://www.scientificsonline.com/thermal-liquid-crystal-paints.html

My Nitinol supplier   $19.99  http://www.ebay.com/itm/Super-Elastic-Nitinol-Niti-New-Power-Technology-/330696040468?pt=LH_DefaultDomain_0&;hash=item4cff052014

Specs of this Nitinol: 40 feet of  .020" diameter super elastic nitinol wire. Ideal for power conversion. It is unformed and requires forming before use. This wire can lift 30 pounds almost 30 inches with a ~30 degree F change.  40 feet weight 16.54 grams.  If you want to drive yourself crazy, try to figure out why this stuff is not over unity.  Here's a design that can run your car.  http://www.pacificsites.com/~snyder/Ebay/Nitinol/high_efficiency_power_conversion.htm
 
Shipping outside the U.S. is $1.00 He ships it in an envelope and i get it in 2 days after i pay .
« Last Edit: September 25, 2012, 07:51:17 PM by gadgetmall »

Paul-R

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Re: Air Temp Nitinol
« Reply #96 on: September 25, 2012, 04:19:05 PM »
there is a nitinol pdf that was on the Internet and can't find it any more.
NASA has done some stuff on it:
http://ntrs.nasa.gov/search.jsp?N=0&Ntk=All&Ntt=nitinol&Ntx=mode%20matchallpartial

The fourth item, "the effects of thermomexchanicla history..." might interest you.

Cherryman

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Re: Air Temp Nitinol
« Reply #97 on: September 25, 2012, 04:43:55 PM »
Hi gadget,


I couldn't resist and ordered some as well.


The same as in your link above. 


Now I can play along ;-)




gadgetmall

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Re: Air Temp Nitinol
« Reply #98 on: September 25, 2012, 04:44:21 PM »
Thanks Paul-R--reading it now .

Awsome CherryMan  . Make sure when you get it to not anneal the whole roll at once . I will help if you need advice
I have had a Lot of Cool Gadgets and Stuff in my days but nothing compares to Nitinol . I don't have anything bad to say about it and Neither do the people who invented(NOL) it except that it would blow the  energy Giants out of business if it caught on..


I was trying to find that info about bending it when its austinite  it give heat and cold when released in that state ..can't find it but did find this :

Stress Induced Transformation Experiment using a Liquid Crystal
The solid-solid phase transformation displayed by SMAs such as NiTi is at the heart of their unique behavior. Students are able to easily grasp the concept of the transformation event when they are able to observe it visually. A dramatic method to observe the NiTi transformation is by employing a liquid crystal that changes color in the appropriate temperature range. In fact, if phase change is the topic of class discussion, the liquid crystal itself is an excellent additional example to consider.
If an austenite wire is loaded in tension, transformation to martensite can be induced. Accompanying this transformation is the release of latent heat. Thermocouples mounted at intervals along the wire can be used to measure the temperature, or a liquid crystal can be used to visualize the transformation front and watch its movement. In a temperature sensitive liquid crystal, an environmental effect such as temperature change impacts the orientation of the liquid crystals. The subtle change in molecular structure affects the wavelength of light that is Figure 3. NiTi wire during absorbed or reflected by the liquid crystal, resulting in an transformation from austenite noticeable change in color of the material. to martensite is shown. The
wire has been painted with a temperature sensitive liquid
To conduct the experiment, acquire NiTi wire (alloy type SE-
crystal so that the
508 (austenite) straight, black oxide finish, diameter 0.02 in.,
transformation front can be
from Nitinol Devices and Components, www.nitinol.com) and
distinguished by the color
liquid crystal (liquid crystal BM/R25C5W/C17-10, 15 g; and
change seen.

Tom Booth

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Re: Air Temp Nitinol
« Reply #99 on: September 25, 2012, 05:03:15 PM »
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 ?

gadgetmall

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Re: Air Temp Nitinol
« Reply #100 on: September 25, 2012, 07:22:34 PM »
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
« Last Edit: September 25, 2012, 08:50:17 PM by gadgetmall »

gadgetmall

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Re: Air Temp Nitinol
« Reply #101 on: September 25, 2012, 09:12:02 PM »
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 ..
« Last Edit: September 26, 2012, 04:55:47 AM by gadgetmall »

Mark69

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Re: Air Temp Nitinol
« Reply #102 on: September 25, 2012, 10:09:54 PM »
Excellent work Gadget, looking forward to your progress  8)

moflint

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Re: Air Temp Nitinol
« Reply #103 on: October 06, 2012, 06:17:59 PM »
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

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Re: Air Temp Nitinol
« Reply #104 on: November 04, 2012, 06:49:19 PM »
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.