a new type of heat engine.

[billswan]

Well not really......

Has anyone here heard of the metal Nitinol?

Seams it is an alloy of nickel and titanium.

Was loitering through youtube and ran onto an old news clip that caught my eye.

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

Seams as back quite a few years ago people had figured out how to use this stuff to make power from low grade heat.

Wounder why we don't see anything like was in the news clip in use?

Here is a second clip about the nitinol metal.    http://www.youtube.com/watch?v=Y7jjqXh7bB4

Billswan

[squarebob]

You can buy one on Amazon:

http://www.amazon.com/Images-SI-HE-01-Nitinol-Engine/dp/B000796XU0

[billswan]

You can buy one on Amazon:

http://www.amazon.com/Images-SI-HE-01-Nitinol-Engine/dp/B000796XU0

Well that is a toy.....

Was meaning something more useful.

In the first video it was mentioned that 600$ worth of nitinol would build a devise that would yield 1000 watts per hour. That probably does not include all the supporting parts and or structure but 1000 watts is nothing to blow off. That is significant power. Pumped into a battery it would be all the power most small homes would need for lighting and then some......
Even here in southern Minnesota on a hot clear day a small solar hot water heater would power it. Or so it would seam to me............Maybe I did not understand the explanation. Seams some one in the video said the efficiency beat photovoltaic cells..........

Billswan

[Tom Reed]

I used to make that metal alloy. It is not east to make! It works outstanding for stents too.

[BruceM]

The comparisons to PV were in the 70s when PV prices were sky high.  I suspect that there were problems in scaling or longevity, as otherwise many industrial settings could have used this for waste heat recovery.  Few "breakthroughs" in laboratory settings make it to the real world.

[Henry W]

Ran into this again.
What do you think?

Here is a more recent clip on the stuff: https://youtu.be/wI-qAxKJoSU

[mobile_bob]

iirc the first time i saw reference to this stuff "nitronol" was in the early 90's
being used in robotics to make up metal muscles

they also made mention of its use in surgical instruments, where a surgeon could bend something like a scalpel to
get it in somewhere tight, and then when placed in an autoclave for disinfection/santization  the blade would return to its original shape

pretty cool stuff

probably expensive too?

bg

[Tom Reed]

Yup, I think robot muscles are where this material will shine. Think of 2 opposing shapes, contracted and relaxed, and apply a small voltage to heat for the direction desired.

When making Nitonal the Ti and Ni really don't want to mix so they tend to separate while molten. We would place a large conductor around the copper crucible that the electricity for the torch flowed through. This would couple to the molten material and it would spin. Fascinating to watch. The other issue is that this material tends to expand when cooling (another unique feature) and stick to copper. We were one of the few places in the world that could make it reliably.