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Posted by John Nagle on July 7, 2008, 4:09 pm
Larry Snyder wrote:
>> HI All. I am developing a motor using super elastic nitinol wire and have
>> problems.
...
>> I am hoping to put this on a bicycle and operate
>> with solar power.
This is one of the more inefficient schemes for converting
thermal to mechanical energy ever developed. Only a tiny fraction
of the energy in the water bath (on a bicycle?) will be transferred
to a thin wire running through it. Nitinol only converts a few
percent of the heat energy to mechanical energy. So you get to
multiply the efficiencies of two low-efficiency processes to get
a very tiny number.
Nitinol is mostly a solution looking for a problem.
> HI All. I posted this on several newsgroups and got a lot of responses.
Please don't do that.
John Nagle
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> problems.
> Picture at: http://www.pacificsites.com/~snyder/motor.jpg The most
> frustrating problem is joining the wire together. I bought some tiny
> stainless steel tubing from Ebay. The idea is to use this as a sleeve and
> solder/braze it together. It hasn't arrived yet. I have been unable to
> find small high pressure crimp fittings.
> The second problem is the wire slipping on the pulleys. I will send
> anyone coming up with a solution to either of these problems a piece of
> wire to play with, assuming it is something I can use. Wire description
> at: http://www.pacificsites.com/~snyder/Ebay/Flexinol%20Test%20Data.htm
> This wire has a transition temp ~100C. This helps resolving the cooling
> side. The heating side can be easily insulated with cheap
> materials(styrofoam). I am hoping to put this on a bicycle and operate
> with solar power. Any comment/suggestions are welcome. Thanks in advance.
> Larry