Nitinol: Free And Virtually Unlimited Fuel To Heat Your Home

[deejaaa]

i apologize if this has been discussed before but after a search, nothing came up ,so thought i'd post it. stumbled upon it during a search. interesting but seems to have gone nowhere. has there been anything to have come from this metal?

https://www.youtube.com/watch?v=-o0-QhLJSk4&spfreload=1

sounds like one of those unbelievable video stories.

[ThermionicScott]

I'm struggling to figure out how the video title and teaser shot relate to what's actually in the video. (Cynically, I guess it may be simple: gain subscriptions to their channel and get people to view banner ads.)

Wikipedia says it's not so easy to make, but does have some uses: https://en.wikipedia.org/wiki/Nickel_titanium

[deejaaa]

Originally Posted by ThermionicScott

I'm struggling to figure out how the video title and teaser shot relate to what's actually in the video. (Cynically, I guess it may be simple: gain subscriptions to their channel and get people to view banner ads.)

Wikipedia says it's not so easy to make, but does have some uses: https://en.wikipedia.org/wiki/Nickel_titanium

i had the same thought. never got to it so quit watching.

[ThermionicScott]

Taken on its own merits, the video clip was interesting, though. I had never heard of nitinol before. Seems to behave somewhat like a bimetallic spring, but in the form of a homogenous alloy. And it's good to see discussions about making use of waste heat -- we need more of that. So thanks for posting it anyway.

[RedDevil]

The video shows how nitinol can be used to convert a temperature difference into motion.
It is in effect a heat engine.

It all depends on the temperature range for the phase transformation.
While the phase transformation can occur in a temperature difference window of just 20 degrees Celsius, the boundaries of that window are fixed
(the height of the range depends on the titanium/nickel ratio in the alloy).

Even if the range is not that big, the cooling temperature need to be at or below the fully flexed threshold and the heating at or above the fully recovered state. So you do need a well controlled stable heat and cold source.

Stirling engines, to name one other type of heat engine, do not have those limitations.
They work if there is a temperature difference and are usually not very sensitive to the absolute temperatures. A Stirling engine that runs when one side is scorching hot and the other just boiling hot may run just as well if one side is at room temperature and the other side freezing cold.
Nitinol can't do that.

There are pros, though.
As the material itself is the actuator, nitinol engines can be mechanically simpler than other heat engines. Some machines have no moving parts other than the nitinol itself, rendering them 'solid state' machines.
Nitinol is very deformable and very resilient; it can generate large pressure when heated mildly.
It seems to improve with age, as repeated use seems to help it perfect its alloy structure by forcing misplaced atoms into position. That also makes it very stable and long-lasting.

If the goal is to generate electricity, it still has to run a dynamo.
Seebeck generators do the same and are true solid state devices. They are not very effective though.

Anyhow, all these devices do more or less the same: convert a temperature difference to another form of energy.
The problem is not the heating side but the cooling side. The less hot you want it, the larger the cooling area needs to be; exponentially so. Yes we can get a few hundred Watts from tapping exhaust or coolant heat. But we need radiators about as big as the one used for the engine.

Likewise the A/C system has a radiator that is fairly large while the heat it sheds is just a tiny fraction of the heat that the engine produces. It needs to return colder fluid, so it needs to be relatively big.
We do not need a second A/C radiator just to gain back a few hundred Watt. The extra weight and cost would kill the benefit.

Nitinol is a nice material, but not likely to make it into cars for power scavenging purposes.

[Logic]

https://www.youtube.com/shorts/sCIGSCqojWk

https://www.youtube.com/watch?v=Mk1pu5-M7DE

So where are the Nitinol Car bodies???

[Logic]

Originally Posted by Logic

https://www.youtube.com/shorts/sCIGSCqojWk

So where are the Nitinol Car bodies???

So you have a little 'Fender Bender' accident.
You pour boiling water on the bent bits and they go back to their original shape.
Perhaps some paint touch-up is required and then it's like it never happened.

ie: Very easy, DIY fix car bodies.
Yet 'we' don't find that interesting!?
Do 'We' prefer the old hundreds of $$ and weeks of waiting, or/and the scrap and replace method??

[RedDevil]

I'd love to have a car made of nitinol. But I fear I could not afford one.

It depends on who you'd ask and the quality of the material but nitinol is priced at over $100 dollar per pound. So if you'd replace a steel body with nitinol you'd add tens of thousands to the cost.

Even if you change just the most vulnerable parts several thousands would be added to the price. If you don't get involved in a good number of fender benders you'd never recoup the cost. And if the accident shears off or rips part of the nitinol then the repairs would be far more costly than if it would have been steel.

[Logic]

Originally Posted by RedDevil

I'd love to have a car made of nitinol. But I fear I could not afford one.

It depends on who you'd ask and the quality of the material but nitinol is priced at over $100 dollar per pound. So if you'd replace a steel body with nitinol you'd add tens of thousands to the cost.

Even if you change just the most vulnerable parts several thousands would be added to the price. If you don't get involved in a good number of fender benders you'd never recoup the cost. And if the accident shears off or rips part of the nitinol then the repairs would be far more costly than if it would have been steel.

Good point!
I wonder what economies of scale would do for nitinol prices?

Then there's the question of what is the lifetime and ecological cost of:
1 car per ~50 years (thumb suck average, with Boric Acid lubricant)
vs
1 car per ~5 years..?

As car makers want to sell as many cars as they possibly can, we'll never know.

[RedDevil]

Batteries get better and cheaper, the point where an EV is cheaper to make than a conventional car is very near.
EVs are mechanically much less complex, with little to fail and maintain, so they'll be kept on the road for much longer - until the battery fails, but state of the art batteries seem to last up to or over a million miles.

That will make the economics of collision damage repairs even more important than it used to be. Whether nitinol can play a role needs to be seen.

I think the smart approach is to design for damage-prone parts to be cheap and easy to replace.
Tesla did so with the rear hatch of the refreshed Model Y: the diffuser (a single-mould piece of plastic) now acts as first-impact bumper as it sticks out further and higher up. The hatch is now recessed and segmented in smaller parts, just like the corners of the car. In the old version a slight hit on the bumper could require the whole hatch needing replacement.