[bower]

Has anyone tried scaling one of the "Coffee Cup" LTD engines up to see if any real effort can be realized over and above operational friction, just curious.
I'd love to see pic's of an LTD of the "Coffee Cup" variety scaled up to say the size of a 5 gallon Paint can.
Is anyone experimenting?

[nick.gilling]

Interesting ... like you say, it should work providing the frictional losses can be kept to a minimum and everything is balanced nicely.

[bower]

I'm hoping someone gives me a tin of butter cookies this Xmas, I've already got the foam to make the displacer.........

[yetiman]

Just curious, has anyone done anymore work on any prototypes? I got interested in stirling engines and started doing some research and found this thread right here on the zone. Didn't realize that there was a stirling engine section to the forums here.

My ideas seem to be running toward the same direction as everyone else. Tie in a solar heating system to a stirling and produce electricity as well heat in the winter then just the electricity in the summer months.

[greybeard]

Hi Yetiman.
Just to let you know that my own project is only on hold until some of the others I have get a little more advanced, or the spring sun comes out, whichever is the soonest.
Once I've built the new greenhouse it will need the under soil heating pipes laid in the beds. That will be a good incentive to get the solar mirror built. Then comes the stirling engine to act as an alternative output source for the mirror, and so on........
Somewhere in the queue is a cnc machine and a tricycle tandem !

Regards
John

[CJL5585]

John,
You are not the only one with the project on hold.

I too have a good solid list of things to do, and a reason for the delay on my Stirling Engine project.

My problem is that the aluminum round stock that I purchased to make the pistons will not fit in my 3 jaw chuck on my mini-lathe. In addition, the material for the cylinders is even larger, so that is my situation.

In the meantime, I am building a vacuum table in order to do some photographs in wood that were promised last summer. Also, I am thinking about building a touch-probe (another scratch design), trying to get my building cleaned out and cleaned up, installing some new flourescent lights and so forth, and on and on.

Just to up-date the thread.
Jerry

[yetiman]

Thanks for the replies guys. Not trying to irritate anyone was just curious. This stuff is fascinating to me, but with the situtation right now I won't be doing any building myself for a while. Hunting a job right now. So I'm just kicking ideas around house for now and doing quite a bit of hen scratching on the graph paper. I'll keep an eye on this thread to see where it goes and add to it when I can.

[yetiman]

I've been doing some more research and came across these
This link mentions the sunpower stirling generator
http://www.ent.ohiou.edu/~thermo/me3...tirlCogen.html

and this one has some more specifics on it.
http://www.sunpower.com/lib/sitefile...ns/Doc0098.pdf

These types of engines are the ones used by nasa and were mentioned earlier in the thread but I didn't remember any links.

[rickharris]

Effective Stirlings often use exotic and hard to confine gases to improve heat transfer.

Most of the model designs will scale up withe the exception of the Low temp family (imagine the size of the coffee cup).

A lot of museums have examples of 1800s Farm engines.

http://freeenergynews.com/Directory/...ine/index.html

May help.

[BobWarfield]

It's a pitty this one didn't get further. It's a fascinating project. A Stirling similar to the Sunpower unit affixed at the focus of a surplus C-band satellite dish with mylar "space blanket" reflector seems very doable for a talented home machinist.

Cheers,

BW

[greybeard]

Hi Bob.
For my part I need to build the cnc to rout the ribs to make the solar dish to hold the stirling...........
....and a bit of sunshine would be encouraging

John

[BobWarfield]

greybeard, my appologies! The rumors of the thread's demise were greatly exaggerated.

I had been pondering this sort of thing quite a while since reading an article about a study showing a dish on 2 normal sized house lots could feed 100 houses with electricity. My interest was in whether a C-Band (old school) satellite dish would produce useful amounts of power.

Reading this thread was sufficient impetus for me to finally gather up my old notes and put together a page on my web site about it:

http://www.thewarfields.com/cnccookb...gGenerator.htm

I'll be watching this all with interest. From my perspective, the Stirling is the hard part. I don't think the solar reflector would be difficult at all to build, with or without a surplus satellite dish. The free-piston linear generator designs seem ideal for this purpose, but I've never seen an amateur constructed Stirling of that kind. I also ordered several Stirling books for research, so we'll see whether I find anything helpful. There's tons of useful data on the Sunpower site as was mentioned above.

Cheers,

BW

[greybeard]

Please keep us posted Bob, and thanks for the link to your pages.
It's been quite some time since I visited this thread, so my knowledge base needs updating. It's going to take me some time to read through all your info, but it will focus the grey matter somewhat while waiting for epoxy to set
However, my original plans to use a stirling as part of improving our energy situation here in the wilds of Norfolk UK are still important to us, if not even more so now with the way things are going, so thanks for the prompting.
Regards
John

[Geof]

....I had been pondering this sort of thing quite a while since reading an article about a study showing a dish on 2 normal sized house lots could feed 100 houses with electricity. My interest was in whether a C-Band (old school) satellite dish would produce useful amounts of power.....Cheers, BW

Go all the way back to post #5 in this thread. As it says the record for efficiency in solar to electric is held by a focussing collector Stirling system. The post doesn't mention the efficiency and I couldn't find it in the links but I think it was 20 or 27%.

Solar energy is approximately 1000 watts per square yard at full noon day sun so you can figure out what you can get if you can build something with this efficiency. I think the 100 houses from the area of two lots may be optimistic.

[BobWarfield]

Go all the way back to post #5 in this thread. As it says the record for efficiency in solar to electric is held by a focussing collector Stirling system. The post doesn't mention the efficiency and I couldn't find it in the links but I think it was 20 or 27%.

Solar energy is approximately 1000 watts per square yard at full noon day sun so you can figure out what you can get if you can build something with this efficiency. I think the 100 houses from the area of two lots may be optimistic.

Perhaps they're counting on some sort of load sharing scheme to require less power?

Here is a more recent article (couldn't find the original, doh!):

http://www.sprol.com/?p=265

Their claim is 37 foot dish is good for 8-10 homes. That would not be that crazy to squirrel away one of those for every 8-10 homes. People pay a premium today for housing developments with features like golf courses and air strips. Perhaps there's enough green sentiment to want a solar community.

In any event, I'm more interested in something more feasible for the amateur to fiddle with.

[greybeard]

Bob, can you suggest why the high(?) level of noise from that system your link describes? I've not come across noise levels as a problem of stirlings before.
John

[BobWarfield]

Bob, can you suggest why the high(?) level of noise from that system your link describes? I've not come across noise levels as a problem of stirlings before.
John

Sorry John, no good ideas on that. The mechanism doesn't seem to me would be loud at all, and it's hermetically sealed to boot!

Cheers,

BW

[greybeard]

OK Bob, you've got me thinking again !
This is slightly off topic, but I would be very grateful if someone could point me towards the necessary source of the maths for the following.
It occurs to me that while it would be nice to have a huge dish, the physical appearance of say a 10ft diameter paraboloid at the bottom of the garden might not be seen as particularly neighborhood friendly.
(I'm just going with the idea of a dish, and not considering a long parabolic trough.)
So in order to reduce the visual impact, I thought of an oval(?) paraboloid. I'm sure there must be a proper name for it, but I have in mind a shape with the same collecting power as the 10ft dish, but vertically challenged ie about 12ft wide but only 8ft high.
As the framework for the dish will be plotted and cut by cnc, the additional complication of the shape is more conceptual than practical. (He said hopefully)
The more I think about it, the more I like the aesthetics of the shape I have in mind, so thanks in advance to anyone who can help.
Yes, I know it's crazy, but you have to make allowances.
John

[Geof]

Rather than an ellipsoidal parabola why not a trough collector? These focus the solar radiation to a line not a point and are less complicated because they only need to track the sun vertically by rotating around the axis of the parabola which runs along the trough. Here are some links (which may be a bit repetitive.


http://www.powerfromthesun.net/chapter1/Chapter1.htm

http://www.ingenia.org.uk/ingenia/ar...aspx?Index=244

http://thefraserdomain.typepad.com/e...parabolic.html

http://www.cogeneration.net/paraboli...collectors.htm

[greybeard]

Rather than an ellipsoidal parabola why not a trough collector?

Quote my post yesterday ......"(I'm just going with the idea of a dish, and not considering a long parabolic trough.)"