Stirlings?

[nick.gilling]

Hello,

I am currently designing a simple stirling engine and will post up some pics soon. Not sure where I'll put them but probably in here! If they get removed, so-be-it but I'm sure it'll be of some interest to somebody.

In the past I've only made model steam engines but want to try a stirling engine before I attempt an IC engine.

Nick

[balsaman]

A great idea. I am working on adding a Stirling Engines section to the forums...Won't be long.

Eric

[epineh]

Send those pics Nick, I for one am quite interested in seeing a working engine, but I must resist the temptation to have a go myself, I found I get more achieved if I limit myself to 100 unfinished projects at a time... once I get my router made then that will be a different story, can't have only 99 things going at once hehe

I get the theory of the engine now but still find it hard to believe it actually works

Russell.

[nick.gilling]

I know what you mean, I still have a problem seeing how the air is cooled and heated so fast! What's even more baffling is the low temperature differential ones, they only need a delta T of a few degrees to work.

I have to confess to actually buying one of these from e-bay, just to get an idea of dimensions used etc. It works from the heat absorbed from your hand.

The first one I am going to attempt though, will hopefully run off a tea light. I presume it will be easier to get a hot air engine to run if it's got a bigger temperature differential.

No doubt we will soon find out!

Good idea Eric to add a Stirling section, there are whole societies for Stirling engines and I'm sure people will find it interesting.

Nick

[RepairmanSki]

I'm glad there is interest. I for one am certainly interested, obviously since i posted =)

I have found these forums as a whole to be full of useful information and even more packed with interesting, helpful members. I am also quite glad to hear about a new subforum being created for the Stirling, thanks Eric!

[pminmo]

If you start running though Sterlings and heat differential engines, there are some amazing configurations. The one thing that has me stumped, I kind of thought there would be some references to utilizing R134 or R22, ammonia, etc for gas, and thus helping the heat/cool cycle.

"Liquid ammonia boils at any temperature greater than -28°F and will expand to 850 times its liquid volume. One gallon of liquid will expand to 850 gallons or 113 cubic feet of gas."

Look up "icy ball".......

[Geof]

If you start running though Sterlings and heat differential engines, there are some amazing configurations. The one thing that has me stumped, I kind of thought there would be some references to utilizing R134 or R22, ammonia, etc for gas, and thus helping the heat/cool cycle.

"Liquid ammonia boils at any temperature greater than -28°F and will expand to 850 times its liquid volume. One gallon of liquid will expand to 850 gallons or 113 cubic feet of gas."

Look up "icy ball".......

Did you not find anything about using helium. I seem to remember reading something a long time ago about the idea of using helium because it has a high heat conductivity so the gas can cool and warm quicker.

[jans123]

Did you not find anything about using helium. I seem to remember reading something a long time ago about the idea of using helium because it has a high heat conductivity so the gas can cool and warm quicker.

You are right about helium and it is used in the most efficient Stirlings. Helium is also a very small gas molecule that has a low mass and moves very fast. The other heavier gases mentioned in the beginning of this line of the thread (like the coolant media in refrigerators) are less suitable in a Stirling engine. They have a high weight and change easily phase and might be better of(???) in a sealed steam engine. By the way, I experimented with propane in a low temperature sealed steam engine… let’s say that that experiment will not go any further… and please all of you, avoid such adventures.
/jan

[pminmo]

Can't say I looked into helium, never thought about gas weight.

Jan
I've wondered about low temp sealed steam engines, can you give me some insite?

[One of Many]

You know something has potential when military applications people take notice and further the progress that will eventually trickle down. For the length of time these have been a limited viable resource, not much change has taken place to eek out every last ounce of efficiency they can muster.

One tidbit article that mentions these advances.

DC

[40fordcoupe]

Our Swedish navy use them in their submarines and those engines are very complex, /jan

Here are a couple of links that tell more about these amazing submarines.
http://www.kockums.se/Submarines/aipconversion.html
http://www.kockums.se/

[jderou]

They are low power/low efficiency and can therefor be a pain to get a model running properly.

Had to point this out because I don't want newcomers getting the wrong idea. They are actually much more efficient than any ic engine.