Solar powered Gamma Stirling Engine

Discussion on Stirling or "hot air" engines (all types)
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Marco
Posts: 6
Joined: Fri Oct 03, 2014 8:01 am
Location: Germany, Kleinwenden

Solar powered Gamma Stirling Engine

Post by Marco »

Hello,

I would like to show you my last stirling engine. At the moment I try to optimize the power output by machining a new displacer. Later I will show some details. The Engine is mounted in the focal point of a parabolic mirror. The mirror follows the Sun automatically.

[youtube]https://m.youtube.com/watch?v=dFGvRSGn7Y8[/youtube]



Best regards.
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Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Solar powered Gamma Stirling Engine

Post by Ian S C »

Marco, does your motor drive an alternator or something with the belt drive. A well made motor, you better get your fingers out of the focal point.
The solar power I'v used was with a large Freznel lens 600 mm x 400 mm, the temperature was hot enough to etch a line on the hot cap.
Ian S C
Triangle.Stirling
Posts: 133
Joined: Mon Sep 09, 2013 8:29 am

Re: Solar powered Gamma Stirling Engine

Post by Triangle.Stirling »

That looks really good!
I'd like to see some video footage of that!
How did you make the parabolic mirror?
It seems to me you glued very many little mirrors on a dish or something?

Regards,

Krijn
Marco
Posts: 6
Joined: Fri Oct 03, 2014 8:01 am
Location: Germany, Kleinwenden

Re: Solar powered Gamma Stirling Engine

Post by Marco »

Hello,

yes, it drives an alternator, output 10V, so far. On the picture the mirror was not fully aligned and it was cloudy. On sunny days, the mirror is very powerfull and dangerous, I always wear protection goggles. Meanwhile I canged the mirror to a commercially buyed one. It is a bit better than my hand made. Diameter of the mirror is 63 cm. On the pictures you can see the new mirror and my new designed displacer.
Krijn your are right, my first mirror was made of small mirrors which I glued on a rooftop dish.

Here is a video of my engine:

[BBvideo 425,350]http://www.youtube.com/watch?v=dFGvRSGn7Y8[/BBvideo]

Best Regards
Marco
Attachments
New Displacer with Graphit and improved air flow.
New Displacer with Graphit and improved air flow.
Displacer_Final.jpg (99.74 KiB) Viewed 5682 times
Stainless steel cap, not machined.
Stainless steel cap, not machined.
Displacer_with_Cap_not_fully_machined.jpg (104.04 KiB) Viewed 5682 times
Aluminium base of the displacer.
Aluminium base of the displacer.
Displacer_without_Cap_and_Graphit.jpg (104.19 KiB) Viewed 5682 times
Marco
Posts: 6
Joined: Fri Oct 03, 2014 8:01 am
Location: Germany, Kleinwenden

Re: Solar powered Gamma Stirling Engine

Post by Marco »

Some more picture:
Testing the new displacer and increased heat exchange surface.
Testing the new displacer and increased heat exchange surface.
Test_Displacer_improved_heat_exchanging_surface.jpg (115.1 KiB) Viewed 5682 times
Testing the new mirror.
Testing the new mirror.
Solar_Stirling_new_mirror.jpg (181.75 KiB) Viewed 5682 times
Marco
Posts: 6
Joined: Fri Oct 03, 2014 8:01 am
Location: Germany, Kleinwenden

Re: Solar powered Gamma Stirling Engine

Post by Marco »

Hi everyone,

I would like to show you two more pictures. On the first one you can see the parts of my stirling engine. One the left side you can see the first design of the displacer.
The generator was also changed to an stepper motor which generates more power output.

The second picture shows a simply fixture which I needed to get the mounting pad installed at the mirror. It is bonded with silicon.





Best Regards
Marco
Attachments
Solar Stirling Parts.jpg
Solar Stirling Parts.jpg (177.85 KiB) Viewed 5654 times
Mirror Mounting Pad Installation Fixture.jpg
Mirror Mounting Pad Installation Fixture.jpg (121.75 KiB) Viewed 5654 times
Triangle.Stirling
Posts: 133
Joined: Mon Sep 09, 2013 8:29 am

Re: Solar powered Gamma Stirling Engine

Post by Triangle.Stirling »

Marco,

That is extremely beautiful!
New mirror is awesome! I watched the video and it runs really nice. Very beautiful engine and setup.
It looks really professional designed. I assume it is your own design? Did you draw it i a CAD program first?
Hope you can get some more electrical power out this, would be really cool.
Is this pure for a hobby purpose? It seems there is a lot of time in designing and building this, i assume you're an engineer?
The solar tracking system is also from Greenpowerscience? Their mirrors are really nice, but a bit expensive.

Regards from the Netherlands,

Krijn
Marco
Posts: 6
Joined: Fri Oct 03, 2014 8:01 am
Location: Germany, Kleinwenden

Re: Solar powered Gamma Stirling Engine

Post by Marco »

Hello Krijn,

thank you for you comment.
Engine and solar mirror mounting are by my own design. Most parts I draw with a CAD (Solid Edge) program to see if and how it works when assembled.
Yes, your are right I work as an repair engineer. But building stirling engines is only for fun.
The tracking system is also from Greenpowerscience. You can find equivalent systems from chinese traders however I decided for this product because it seems of a higher quality.
It has a lot of additional functions which I not use at the moment. It works very well, I am very satisfied with it.

At the moment, I improve some of the parts of the gamma stirling engine which I use at the solar mirror. I want to finish it by the end of the year. However, I think it is not the best engine.
Along the way I started to design and build an alpha stirling engine for the solar mirror. First parts are finished and I will show them in one of my next post. Hopefully it can be finished and tested next summer.

Best Regards
Marco
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