Thermoacoustic engine from trash

[Free_WiFi]

This man is just a genius

[cdev]

I recognized Helmholtz resonance!  I don't speak Russian, unfortunately.

So, what exactly is going on, I suppose I should just look up thermoacoustic engine.. okay..


https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine

>> https://en.wikipedia.org/wiki/Rijke_tube

He has what appears to be a large neodymium magnet, the tubes appear to be sealed (?) except for where the magnet is?

This is a fairly efficient generator that is easier to build than an electromagnetic one.

[Free_WiFi]

The tube is completely sealed,the magnet is glued on the top of the rubber of tube.

[jpanhalt]

There is some similarity to the "acoustic laser" built at Pennsylvania State University (aka Penn State) about a decade ago:

http://www.acs.psu.edu/thermoacoustics/refrigeration/Demo_Inst5(no_specials).pdf

I bought the kit at that time and it is neat.   The link still lists it, but I didn't check to see if orders were still being taken.

John

[IanMacdonald]

Would seem to use the same principle as the free piston Stirling engine, with the sound acting as the displacer piston.

Stirling engines are/were used to power electronics in areas with no mains. They are not very efficient but are highly reliable and need little maintenance. They will run off just about any heat source. These days they've mostly been replaced by thermocouple generators or solar PV and batteries.

[jmelson]

Would seem to use the same principle as the free piston Stirling engine, with the sound acting as the displacer piston.

Stirling engines are/were used to power electronics in areas with no mains. They are not very efficient but are highly reliable and need little maintenance. They will run off just about any heat source. These days they've mostly been replaced by thermocouple generators or solar PV and batteries.

Yup, it definitely looks like an acoustic Sterling engine (no solid displacer).  Does anybody have a drawing for this thing?
Looks like one of of the tubes he used is made of glass.  Does it have to be?  Is the stuff at one end of the glass tube steel wool?
That would be the regenerator material. That improves efficiency as it retards heat loss from the hot side to the cold side.

This unit seems to be delivering a fair bit of energy, seems you can draw a couple Watts off it without killing the resonance, which is pretty good.
There are lots of micropower Sterling designs out there, but this one delivers at least a bit of real power.

Jon

[jpanhalt]

Does anybody have a drawing for this thing?
Jon

Did you miss something in the PSU link?