Solar-powered home-built Stirling engine

I designed my little testbed engine so it can be inverted and heated from above, and I finally got the opportunity to try it out using solar energy.

I had an old Fresnel lens from a large screen TV that I mounted in a frame and then put the engine hot end at the focus. I was pleased to see that it runs very well, over 1,000 rpm.

Features of the engine: wood frame, ball bearing crank, $1 water bottle cylinder, tuna can cooling jacket, inner tube and PVC power diaphragm, stainless steel wool moving regenerator. Cooling water provided by tiny submersible pump from Harbor Freight. Stay tuned - next generation engine coming soon. This one has about served its purpose.

Category:

Science & Technology

Tags:

• Stirling
• engine
• hot
• air
• motor
• external
• combustion
• appropriate
• technology
• solar
• energy
• heat
• thermal
• AT
• regenerator
• simple
• cheap
• inexpensive
• diy
• home
• built
• Fresnel
• lens
• concentrator
• alternate
• sustainable
• renewable

[leandrojwfolha]

I wonder if you manufacture this lens? which material! I am also interested in having one of these.

[approtechie]

@leandrojwfolha This fresnel lens is from an old large screen 60" projection TV. People get rid of those old TV's when they break since they're so large and heavy, but you can scrounge the lenses from them for all kinds of solar projects.

[gaiatechnician]

Very good work. Could You check my videos for the tracking solar accumulator ?

As you know, solar tracking is the next step for your solar powered stirling engine.

The accumulator videos show how you can do it on equatorial mount

"Model: Fresnel lens on equatorial mount. Burning leaves" is one of them and another useful one is "Model solar concentrator. It works without the focus moving."

Once a stirling entusiast makes one of these, solar powered stirling will become common.

[approtechie]

@gaiatechnician I'd say the one difficulty with your system is that it's best to heat all sides of a Stirling engine heater head equally and the only way I can see that happening is by tracking the engine as well. Uneven heating lowers efficiency and power and can weaken the material. What I did in this video was just a test, not the ideal situation. Any suggestions?

[revolt81]

@leandrojwfolha they can be made from plexiglass...

[Rasta8889]

@approtechie

Yes, the hot end of your engine does seem to be just black metal. I learned that you need a selective coating, that means one that absorbs normal light well and is bad at emmiting infrared light.

These can be bought as a spray.

Black painted metal absorbs normal light well, but emits infrared light because it heats up. If it would be heated up enough, it would glow and even emit normal light that humans can see.

[nazifdaniel]

use motor oil to spread the heat

[MegaMalek95]

wooooooooow

good job

[c5ea]

Use a 10 foot diameter satellite dish to get heat focused on all sides

[gaiatechnician]

@approtechie Thanks for the quick reply. Maybe if it is a metal ball as the heat collector with a flat "hotplate" at one end and the Stirling head goes against the hotplate? The heat will even out as it goes through the metal.

I found the idea (dual parabolic dish solar or one dish and counterweight) by accident. I think it applies to Fresnel too. And I think a fresnel and counterweight is easier to design than the half parabolic dish method.