Author Topic: Stirling power?  (Read 9288 times)

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SatyrTN

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Stirling power?
« on: December 07, 2010, 05:34:23 PM »
Wanted to ask here to see if anyone has tried this already, and what their experience(s) were.

I ran across this video:
http://www.youtube.com/watch?v=DHqYjLbuHxk

The only input seems to be heat from a small alcohol flame.  And the speed of the wheel looks to be simply awesome.

Has anyone tried putting neodymium magnets along the side of this wheel to see what an electrical output might be?  Or anyone see any reason that wouldn't work?

Thanks!
--Ian

Madscientist267

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Re: Stirling power?
« Reply #1 on: December 07, 2010, 08:09:34 PM »
Like computers, GIGO.

What you put in, comes out.

Stirlings are a fascination for sure. Every once and a while you'll find a multi-cylinder version that can use solar/ground water. To me, that would seem like the combo.

As far as trying it myself, no. Does it seem feasible, yes. Throw a Dan/Dan PMA at it, design it right, and I'd bet it would produce some serious juice. Just look at their steam engine generator. 2KW from a little bit of wood. Very promising.

Break the mold and try it dude! I'd LOVE to see the results. I think it's a promising technology. Even NASA has considered a modified stirling for use in space. Do it before they get a lock down on it LOL.

Steve
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SatyrTN

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Re: Stirling power?
« Reply #2 on: December 08, 2010, 10:18:02 PM »
I've got one ordered, so I'm gonna see what I can do with it :)

The next question is about the copper wire.  I'm pretty sure I can glue magnets to the flywheel, alternating their polarity.  But what's the best way to put the copper wire next to the flywheel?  Wind it in a coil?  Any thoughts on that?

Thanks :)
--Ian

Madscientist267

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Re: Stirling power?
« Reply #3 on: December 09, 2010, 06:58:31 AM »
Haven't built one myself, but there are people floating all over this board that could tell you exactly how to do it. Check in the 'Wind' department.. there's plenty of good pics and such. For example:

http://fieldlines.com/board/index.php/topic,144312.0.html

Scroll down past the blades and you'll see just about step by step how that particular alternator was made. Granted, a small stirling isn't going to be capable of 2KW, but the concepts are exactly the same, just would be scaled down a bit.

Steve
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kensue49

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Re: Stirling power?
« Reply #4 on: December 09, 2010, 07:09:48 AM »
My youngest daughter and I built this version in 1990 for a Science Fair project.

Scientific American, v262 n1 p140-44 Jan 1990
The Amateur Scientist. A Backyard Version of a Stirling Engine Can Be Built with Common Materials.

It cost about $ 40.00 at the time because we bought all new material.

I don't think that one would have produced any power but it would crank along at about 120 rpm as long as you could keep the cycle temps hot/cold enough.
Here is what we built -http://www.science-project.com/_members/science-projects/1990/01/1990-01-body.html
That was a fun time. ;D
« Last Edit: December 09, 2010, 07:13:23 AM by kensue49 »

kensue49

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Re: Stirling power?
« Reply #5 on: December 09, 2010, 11:55:07 AM »
Sorry, I should have said 12 rpm NOT 120 rpm.

Madscientist267

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Re: Stirling power?
« Reply #6 on: December 09, 2010, 02:53:39 PM »
Yeah from what I understand, the gap between the cylinder and the displacement piston is critical to good efficiency. Some of the more precision 'tuned' engines can hit upwards of 1000 RPM. I'd imagine with very large versions, the speed wouldn't be all that high, but you could probably get a good amount of torque. Maybe even a multiple cylinder design. Then, when you have the torque, make the disc on your alternator with a larger diameter to make the angular velocity work in your favor.

There also seem to be two types of displacement systems - gap between cylinder and piston, and hole-in-piston. I haven't even so much as attempted to build either one, but people from both crowds claim advantages/disadvantages to both.

Good luck either way. I know one thing, they're cool to watch. And if they're designed right, they don't really require much input to run (freewheeling that is).

Steve


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Ungrounded Lightning Rod

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Re: Stirling power?
« Reply #7 on: December 09, 2010, 07:18:27 PM »
Yeah from what I understand, the gap between the cylinder and the displacement piston is critical to good efficiency. Some of the more precision 'tuned' engines can hit upwards of 1000 RPM. I'd imagine with very large versions, the speed wouldn't be all that high, but you could probably get a good amount of torque. Maybe even a multiple cylinder design. Then, when you have the torque, make the disc on your alternator with a larger diameter to make the angular velocity work in your favor.

There also seem to be two types of displacement systems - gap between cylinder and piston, and hole-in-piston. I haven't even so much as attempted to build either one, but people from both crowds claim advantages/disadvantages to both.

Even more critical to efficiency is a "regenerator" in the displacement path.  You can put it inside the piston in the hole-in-piston version or in the path around it.  (With the regenerator inside the piston you don't actually have to displace the gas appreciably.  The temperature change from pushing the regenerator through it does the job.

= = = =

Another way to do a sterling is as a 90-degree V-2.

You extend the leading/hot piston and its cylinder head upward with something not too heat conductive (so the main part of the cylinder and piston can be near ambient temperature), stack the cold heat exchanger and the regenerator in the cylinder head of the lagging/cold piston, and connect the headspaces of the two pistons with plumbing through the hot heat exchanger.

Might be interesting to try converting a two-cylinder four-cycle motorcycle engine for this service.  Or better convert a V4 and double up, so you don't pump air in and out of the crankcase on every cycle and do get a smooth power output.

Madscientist267

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Re: Stirling power?
« Reply #8 on: December 09, 2010, 10:04:02 PM »
LOL Point in case, vis-a-vis, I knew someone would really know about this stuff somewhere around here.

Got me thinking, but damn lightning, hahaha wait until I have my other projects completed first before you get me too piqued  :o

ETA: June 7, 2031. hahaha

Steve
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WindriderNM

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Re: Stirling power?
« Reply #9 on: December 11, 2010, 10:59:23 AM »
You could put neos in the piston with coils around it as the piston goes back and forth it would produce AC power.
In the parking lot of the Belen, NM city hall there are 3 large dishes with Stirling generators. I think they work this way.
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Madscientist267

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Re: Stirling power?
« Reply #10 on: December 11, 2010, 11:26:34 AM »
Wow thats friggin awesome dude... Did you check out the specs on those things?

http://www.belen-nm.gov/news/Stirling_Power.htm

"Each engine is capable of producing as much as 3kW of power at 240 VAC." !!!  :o

They're basically mounted on modified 'old-school' satellite dishes for crying out loud! 3KW from a 15 foot dish? SWEET!!!

Cool find man! Might have to reconsider my PV direction into more of a wayward stirling instead! hahaha

Steve
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How much magic smoke it contains does !

Ungrounded Lightning Rod

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Re: Stirling power?
« Reply #11 on: December 13, 2010, 07:12:06 PM »
Wow thats friggin awesome dude... Did you check out the specs on those things?

http://www.belen-nm.gov/news/Stirling_Power.htm

"Each engine is capable of producing as much as 3kW of power at 240 VAC." !!!  :o

They're basically mounted on modified 'old-school' satellite dishes for crying out loud! 3KW from a 15 foot dish? SWEET!!!

Cool find man! Might have to reconsider my PV direction into more of a wayward stirling instead! hahaha

Steve


Those look like the coaxial resonant stirling engines - where the power piston drives the displacer via a spring and the whole thing runs at the frequency where the displacer lags by 90 degrees.  They can have an integral linear PMG and a resonance chosen to be at line frequency or an even integer fraction of it, so the coils can be hooked right to the power line (to give it a kick start and keep it synchronized).

Two moving parts.

Kinda like a moving-parts heat-engine version of the pushed-faster-than-synchronous-speed induction-motor-as-grid-tied-generator hack.

I'd seen articles on these some years back.  It's good to see that somebody actually built and deployed a few.

Madscientist267

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Re: Stirling power?
« Reply #12 on: December 13, 2010, 08:10:43 PM »
I put in for a price quote for a single unit, both installed and 'do-it-myself', just to get a ballpark for comparison to a similar array of PV... IF they respond to me, I'll relay the info.

Steve
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troy

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Re: Stirling power?
« Reply #13 on: January 19, 2011, 11:45:43 AM »
Just to throw some numbers around.

A nicely designed Stirling genset of under 20 hp could be 33% efficient.  A steam powered genset of the same size would be lucky to be 20% efficient.

The Stirling engine concept has been right on the verge of "The Next BIG Thing" for 30 years or more.  It seems to have a hard time making it to market after overcoming all the design/engineering/manufacturing/investment hurdles.

Whispergen I think is the only one to end up with a product you could buy. 

http://www.whispergen.com/

I think there is a boat version that you might be able to acquire, although they might all be set up for that funny european electricity, ie 50 hz.

I built a toy version low Delta engine just to satisfy my curiosity.

There's some interesting youtube footage of the famous Phillips portable generator stiriling, like here:

http://www.youtube.com/watch?v=M9UKu-AP02k

A youtube search for Stirling Engine will get some interesting hits.

Good luck!

troy

WindriderNM

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Re: Stirling power?
« Reply #14 on: January 19, 2011, 02:29:49 PM »
I'm hopping the city decides they don't want them anymore and I can bay them at a surplus auction
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BigBreaker

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Re: Stirling power?
« Reply #15 on: February 16, 2011, 10:06:42 AM »
Stirling engines are difficult to engineer.  They need an efficient heat exchanger that operates at high pressure and high heat.  They need a regenerator with just the right mix of heat retention and low pressure drop.  You want as high a frequency as possible to generate usable amounts of power for a given weight and volume of engine.  Finally you need a way of extracting the power while preserving the seal of the pressure vessel.  Ouch...

If you go down this road, please be mindful of how challenging a stirling is to make, at least one that produces usable amounts of power.  It might be easier to do cogen with a diesel running bio-d or wood gas.

Tritium

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Re: Stirling power?
« Reply #16 on: February 16, 2011, 10:19:53 AM »
Just to throw some numbers around.

A nicely designed Stirling genset of under 20 hp could be 33% efficient.  A steam powered genset of the same size would be lucky to be 20% efficient.

The Stirling engine concept has been right on the verge of "The Next BIG Thing" for 30 years or more.  It seems to have a hard time making it to market after overcoming all the design/engineering/manufacturing/investment hurdles.

Whispergen I think is the only one to end up with a product you could buy. 

http://www.whispergen.com/

I think there is a boat version that you might be able to acquire, although they might all be set up for that funny european electricity, ie 50 hz.

I built a toy version low Delta engine just to satisfy my curiosity.

There's some interesting youtube footage of the famous Phillips portable generator stiriling, like here:

http://www.youtube.com/watch?v=M9UKu-AP02k

A youtube search for Stirling Engine will get some interesting hits.

Good luck!

troy

I contacted Whispergen a few months ago.  Here is what they told me.


Thank you for your interest in the availability of the DC WhisperGen™.

The current DC product is available for marine installations in very limited regions. Whisper Tech is not expanding the distribution network of the DC product at this stage and therefore we are not able to supply our product for your application.

 Kind regards.

Info@whispergen.com
Whisper Tech Limited
PO Box 13 705, 224 Armagh Street
Christchurch, New Zealand
Phone +64 3 363 9293
Fax +64 3 363 9294
www.whispergen.com

Thurmond


Madscientist267

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Re: Stirling power?
« Reply #17 on: February 16, 2011, 10:44:14 AM »
Crazy that it should come up again just as it did...

I was just poking around, and ran across this. Looks like something I personally wouldn't mind messing with.

Who knows how close his numbers are, but it's obviously doing something and i'd imagine a PMA hot-glued/epoxied/welded/bubble-yummed to the flywheel would produce a fairly usable amount of power.

The only thing that gets to me a little bit is the noise... but hey...

http://www.youtube.com/watch?v=5pdqDQwehlk&feature=related

The guy messing with it is apparently not the brightest bulb in the chandelier, but who cares, the thing runs.

I'd be willing to bet that if you set it up with a black-body heat collector, and some cooling coils to circulate groundwater through, this thing would put out even more torque than it is in the video.

Asked him where he got it, haven't received a reply yet.

Steve


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WindriderNM

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Re: Stirling power?
« Reply #18 on: February 21, 2011, 10:34:45 PM »
I saw a prototype nuclear powered car in the 1970s that used a stirling engine. I think it was made in Loveland Co.











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redtick

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Re: Stirling power?
« Reply #19 on: February 22, 2011, 03:25:36 PM »
Crazy that it should come up again just as it did...

I was just poking around, and ran across this. Looks like something I personally wouldn't mind messing with.

Who knows how close his numbers are, but it's obviously doing something and i'd imagine a PMA hot-glued/epoxied/welded/bubble-yummed to the flywheel would produce a fairly usable amount of power.

The only thing that gets to me a little bit is the noise... but hey...

http://www.youtube.com/watch?v=5pdqDQwehlk&feature=related

The guy messing with it is apparently not the brightest bulb in the chandelier, but who cares, the thing runs.

I'd be willing to bet that if you set it up with a black-body heat collector, and some cooling coils to circulate groundwater through, this thing would put out even more torque than it is in the video.

Asked him where he got it, haven't received a reply yet.

Steve


Steve


Look into Andy Ross Stirling Engines. I think it is one of his kits.

Madscientist267

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Re: Stirling power?
« Reply #20 on: February 22, 2011, 04:45:01 PM »
Andy Ross it would be... unfortunately, they don't appear to be available as kits anymore.

I'd really like to see one running a 'fieldlines style' PMA. I'd think it would be possible to directly drive the alternator.

Fresnel lens (or parabolic dish) tracking the solar disk on the hot side, ground loop cooled water circulating in the cooled side.

The engine used in those videos would produce enough power to call it 'worthy' of doing if you ask me.

~50-100W? Sounds good to me.

Steve
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redtick

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Re: Stirling power?
« Reply #21 on: February 23, 2011, 11:11:01 AM »

Harold in CR

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Re: Stirling power?
« Reply #22 on: February 23, 2011, 02:00:51 PM »

 I may have posted this info earlier, but, what y'all are describing is not a new idea.  My Dad was an old time engine, collector. He was given a "Rider-Ericsson" HOT AIR engine.

 We ran it many times. It had a 4" X 6" bore and stroke. Under the bottom of the engine, was a Can shaped device. Could have been a cylinder, you built a fire , or, in our case, put a hot water heaterburner in there, and ran on LPG. There was another "Cylinder"?? above the engine base, and that is where the valve mechanisms were. This unit weighed around 250 pounds, and was 5½' tall.

 It ran a single bore piston water pump, pushing water up into a tank, above the roof of a house or barn. Output was 2 Gallons or so, per minute

 I seriously doubt you could get more than 50 watts out of this rig. It had a flywheel that weighed, probably, 75 pounds or more.

 I just ran a Google and them clicked "Images" on the upper left of the screen, and, there are several photos and Youtubes of those engines.

 As a lot of y'all, I would LOVE to have one that runs off Solar, but, it would probably need water cooling on the cool side, to get sufficient power, IF a Fresnel lens was used to concentrate the suns heat on the bottom side.

 My Son is searching TV repair shops, for a Projection TV. They have large Fresnels in them.

Madscientist267

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Re: Stirling power?
« Reply #23 on: February 23, 2011, 02:25:32 PM »
Oh by far, not a new idea. But 'new' to the DIY crowd.

Stirling engines in terms of what is available to the public, are mostly just novelty items, which is fine, but they can't produce any real power.

You're right about the cooling, mentioned it previously in an earlier post... ground loop cooled water circulating to keep the cool side cool...

It's a tossup in my head ATM if a fresnel lens or a parabolic dish would be better.

One of the demo videos I saw, the guy damaged one of his stirlings using a fresnel because he wasn't using tracking, and he got distracted for just long enough for the heat to focus on parts that shouldn't be heated.

Parabolic dish would solve this, as even without tracking, the dish would simply focus the rays away from the input head, but reflect them before they could hit other parts of the engine.

Drawback to parabolic dish, is you'd have to track the entire engine, not just the lens.

I'd still like to get my hands on one of these and see just exactly what is possible. I'd try to build one myself, but from what I understand, the higher power units require tighter and tighter tolerances, something I don't have the equipment to design for. :(

Steve
 
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Harold in CR

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Re: Stirling power?
« Reply #24 on: February 23, 2011, 03:35:42 PM »

 Somewhere on the 'net, I ran across a guy that had video of running a generator on a Stirling, and getting 1KW or so output. Iy was a homebuilt, meaning, not manufactured in bulk. Guy was probably a machinist.

 Computer puked the Hard drive, and I lost the link. Sound about right.  ::) ::) ::) ::)

 It was a 2 cylinder opposed, I believe. If your search skills are better than mine, try searching. Maybe you will stumble across it and post a link ???  MY search skills are terrible.  ::) ::) ::)

BigBreaker

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Re: Stirling power?
« Reply #25 on: February 24, 2011, 01:59:40 PM »
Anyone interested in Stirling and DIY Stirling would be well served to check out this website:

http://web.me.com/allan.j.o/Communicable_Insight/Welcome.html

It discusses in great detail the optimal dimensions to use in various parts of the engine to achieve a particular set of design goals- RPM, temperature, HP, working fluid, etc... It's a gold mine.

Madscientist267

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Re: Stirling power?
« Reply #26 on: February 24, 2011, 06:55:01 PM »
Excellent, Smithers. ;)

Will check it out for sure...

Steve
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How much magic smoke it contains does !