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low temp engine question

Posted: Mon May 20, 2013 3:21 pm
by tapkoote
I've ordered one of those cheap coffee cup engines.
I've got an old black cast iron pot in the sun in the window
it registers 87.5 degrees, think that motor will run on that?
Pat :question)

Re: low temp engine question

Posted: Mon May 20, 2013 5:08 pm
by theropod2
tapkoote wrote:I've ordered one of those cheap coffee cup engines.
I've got an old black cast iron pot in the sun in the window
it registers 87.5 degrees, think that motor will run on that?
Pat :question)
Yep, BUT there must be a temperature difference, so the cool end might need to be shaded some.

If these little engines will run off the heat from a computer monitor surely your solar collector iron pot will suffice as a heat source. Is this one that's supposed to run off the heat of your hand?

Take and upload pictures!

R

Re: low temp engine question

Posted: Tue May 21, 2013 3:46 am
by Hopper
Best solar LT Stirling I have seen had a clear Perspex top disc instead of the usual aluminium.
The top of the displacer piston was covered in matt black aluminium foil or thin sheet.
So the sun shone through the top of the displacer chamber and heated the black alum. on top of the displacer piston.
Cold end was the usual aluminium disc, but at the bottom of the displacer chamber, sat on a paving stone for cooling.

But the problem you face is the heat coming up from the cast iron pot and the heat coming down from the sun. You will need to somehow shade the cold end of the engine but leave the iron pot in sunshine.

Re: low temp engine question

Posted: Wed May 22, 2013 2:06 pm
by tapkoote
Thanks if I get it to work I'll post a pic
Pat

Re: low temp engine question

Posted: Mon May 27, 2013 11:45 pm
by tapkoote
While working on my POP can engine, I received my low temp engine.
It ran over an hour on a cup of nuked water, 3 hour 50 minutes on one quart nuked (2 min)
H2O.
Haven't the sun to heat the black pot, but did get it on the wood stove.
Not enough heat differential.
How ever I'm going to super glue some cooling fins on the spokes.
Thinking the fan action will over come the force of the fan blades.
Probably nuts- HUH?
I've got -128 rpm-135rpm-127 rpm (in that order) on the thermos.
Thats about an hour into it.
I'll do some tests with hot 2:30 min water with and without cooling fan blades.
And I'm thinking on a way to concentrate the heat off the wood stove/plus the
fan action may get this to work on the stove. (however summer is almost here)
I think.
Here's 3 hours 50 minutes----- excuse the quality, I'm learning the vid thing.
http://www.youtube.com/watch?v=Rv19AtBH ... cg&index=1