How I built a hot air engine almost entirely from junk. I've wanted to build one of these ever since discovering stirling engines in about 2003. Spending the weekend making things in Steveastrouk's workshop gave me the opportunity to make the precision parts I'd need, and I knew most of the engine was going to be made of improvised materials, so decided to see if I could make the entire thing out of scrap or unwanted materials.
If you aren't familiar with how Stirling engines work, there are plenty of resources online- the Wikipedia page is a good place to start.
If you aren't familiar with how Stirling engines work, there are plenty of resources online- the Wikipedia page is a good place to start.
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The "core" of a gamma stirling engine of this design is a large cylinder that holds the displacer, connected to a smaller power cylinder providing the power strokes. I decided to follow Darryl Boyd's "walking beam" design, where the power cylinder sticks out of the side of the dis[placer cylinder, because it suited the materials I had and it looks cool :)
I found that an aluminium drinks can would fit neatly inside a steel soup can, so decided to use that for the displacer on the grounds of being cheap, light and easy to work with. The steel soup can provides a sturdy body for the engine and also meant I could ake the bottom removable to allow maintenance.
I found some decking to use as the base, some 1" x 1/2" pine to use as supports for the moving parts, and a piece of 3/4" aluminium strip to use as the beam. The engine is a messy combination of metric and imperial units- that's what happens when you use scrap materials!
I found that an aluminium drinks can would fit neatly inside a steel soup can, so decided to use that for the displacer on the grounds of being cheap, light and easy to work with. The steel soup can provides a sturdy body for the engine and also meant I could ake the bottom removable to allow maintenance.
I found some decking to use as the base, some 1" x 1/2" pine to use as supports for the moving parts, and a piece of 3/4" aluminium strip to use as the beam. The engine is a messy combination of metric and imperial units- that's what happens when you use scrap materials!
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There is only one piston, which has to be a very close fit in the small cylinder but slide freely, and the displacer inside the engine which needs a small gap around the sides. To understand how the engine works I'd suggest reading the Wikipedia page about them. Briefly, the displacer is there to move air around inside the engine, and the piston is pushed in and out by air pressure. This explains why the parts need to fit the way they do, but to understand the entire cycle you should read more about Stirling engines- there is plenty of information on the internet about them.
thanks for ur response! This is the only thing thats bothering me, otherwise i'm really looking forward to making this!!!
Unless you can make the cylinder and piston perfectly smooth you are aiming for the best compromise between it being too loose (and leaking air) and too tight (and friction taking power away from the engine). I believe loose is generally better for a hand-made first engine. How you do this is entirely up to you, there are a number of possible approaches- check out the many other Instructables on stirling engines.
The displacer pushes the air in the engine to the hot end, where it heats up and expands. This expansion pushes the power piston outwards, because it's the only part of the engine that can move to let the air inside expand. The power piston moving outwards turns the rotating parts around, which moves the displacer and so moves the air inside the engine to the cold end. The air cools down and contracts, and so sucks the power piston back inwards.
The power piston itself needs to be able to move in the cylinder freely, but also to move in the cylinder with a change of air pressure. The simple way to do this is to just glue a cut-out circle of balloon rubber over a hole in the engine, so it will move in and out with changing air pressure. I did it by making a smooth brass tube and a piston to fit very closely in that tube. That way is more fun and can make a more powerful/efficient engine but needs workshop tools whereas the balloon method might only need a knife and some pliers. Check out reukpower's instructables for more on how you can build stirling engines without precision engineering tools.
I picked up some at a camping store
Ideally the displacer should be light, so if you can find one an aluminium drinks can might be better than a thicker steel soup can, but I don't see any reason the soup can wouldn't work.
I can't seem to find any drink cans around, so I'm going to use these cans instead, now that I know that it should work. I shall inform you on how well it runs.
I think it was overheating at the time- with better cooling and a more suitable generator I figure I could get perhaps one or two hundred milliwatts out of it.
Efficiency is pretty poor, I think an average candle puts out something like a hundred watts of heat so we are talking about something like 0.1%. Not great!
That was only running on one candle, though. Heating it with a small cup of meths, it will run at several revolutions per second- it might go faster but I'm afraid to let it run that fast in case something gets damaged in the process. I'll take a video of it running fast and post it in the comments when I have time.
I do oil the crank bearings and the sliding displacer rod- it's possible I hadn't done that when I recorded the video, but it doesn't squeak as much now.
just go to YouTube and search for KS90 and you will see some nice examples!
They also start running when the upper surface of the displacer cylinder is being heated by just letting the sun shine on it!
But they are a bit difficult to align and when building one, you have to avoid everthing which could cause some unneeded friction.
Europe has a lot of CHPs (Combined Heat and Power plants) installed, using biomass to generate heat and electrical energy in housing areas, based on stirling engines. Of course these engines by no way can be compared to the ones you will find at instructables.com, but these are real hitech products, running 30,000 hours and more needing only a small amount of maintenance.
There are small CHPs (15 kW heat and 3 kW electrical energy), just take a look at http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=laymanReport&fil=LIFE99_ENV_D_000452_LAYMAN.pdf
Hungary based FlexEnergy is builing a generator (38 kW output) running on landfill gas (methane) only.
Now you can continue to state "...Stirling engines are at best a curiosity though..."
A 40kW diesel generator isn't newsworthy, its a pallet item.
http://www.google.com/images?um=1&hl=en&safe=off&tbs=isch:1&&sa=X&ei=s7FrTY7PPIO88gaU4LyQCw&ved=0CC8QBSgA&q=40+kW+diesel+generator
About 153,000 results ...
I think we need to distinguish between fantasy and reality but that's just me.
Yes, it most certainly does. It's called proof, and it's not an opinion. You have been proven wrong.
[pfred2: There is likely more steam piston engines still in operation than Stirling engines today.]
Of course there is. Steam is still one of the most efficient and most powerful systems there is. If there wasn't a problem with steam production and storage we'd still be using them in our cars. You're not making a case for yourself. How exactly do you think nuclear power plants work? That's right...steam...
[pfred2: I think we need to distinguish between fantasy and reality but that's just me.]
I guess the sources that Hebinho mentioned are fantasy and not reality? I don't think "we" need to distinquish between fantasy and reality, I think just "you" do.
You may now continue to post opinion...
No I'm not making a case with you! Because you are an unreasonable individual.
I'm supposed to accept a few sources but it is OK for you to ignore the overwhelming number I present? At this point I really don't care what you think.
Fusion isn't even done at a stable level yet. Once fusion reactors are perfected it will be extremely practical and will take the place of current nuclear reactors. You're still wrong in your example.
[I'm supposed to accept a few sources but it is OK for you to ignore the overwhelming number I present?]
Overwhelming number of what? You have produced zero evidence that "stirling engines are at best a curiosity".
Here are 153,000 examples
http://www.google.com/images?um=1&hl=en&safe=off&tbs=isch:1&&sa=X&ei=s7FrTY7PPIO88gaU4LyQCw&ved=0CC8QBSgA&q=40+kW+diesel+generator
That took all of a tenth of a second for our favorite search engine to cough up but you conveniently choose to ignore. Go argue something you've a chance with like extra terrestrials or the Easter Bunny. That ought to be a good one, least you'll have baskets pretty soon as proof!
& Don't argue the stupid position of proposing ethanol, that would require energy to make energy, wasting time & power.
No, it's not. You're basically saying so in the latter part of your statement. Will you ever stop being wrong(Apparently not)? It's not supposed to take a continual energy feed to keep the reaction going. It's only supposed to take energy to start the reaction, and it should keep going for as long as it's stable. You understand what stable means right? ITER is expected to produce a minimum stable reaction of 480 seconds but could be as much as 1,000 seconds, producing 5(on the low end) to 10(on the high end) times as much energy as was needed to start the reaction.
[pfred2: That took all of a tenth of a second for our favorite search engine to cough up but you conveniently choose to ignore.]
You posted the same exact useless link again? That's proving that stirling engines are a curiosity how?(I'll give you a hint: it's not) With the national average for diesel being $3.716 per gallon and some places as high as $3.964, tell me again which one you think is actually more practical? Do you have to keep paying the sun to receive and convert it's energy? A link to diesel generators proves nothing about stirling engines. You'd have to be delusional to think the diesel generator is more practical.
You just choose not to see the relationship. They pointed out one example of a 37kW generator I pointed out 153,000 of similar in just one other technology. Now if diesel wasn't more practical then how come there are so many more examples?
By the same example 100 years ago you would be saying coal powered steam engines were the only solution earth ever needs, claiming petrol engines were a fad.
100 years before that, you would be mocking anyone even thinking anything but a horse could move a cart.
You would probably also be saying that since 90% of carts were drawn by horses, that those carrying heavier loads which required bullocks to pull them should be regarded as imaginary?
It's starting to seem like when you're wrong on one part of a subject you try to bring the attention to a different part, hoping you'll eventually be right about something. Don't change the subject. Where's your proof/argument that current fusion reactors are stable(self sustaining for a significant period of time)? Is this you conceding defeat?
[pfred2: Now if diesel wasn't more practical then how come there are so many more examples?]
How about I answer your question with more questions? If diesel is more practical, why are there more gasoline engines on the road today? Why are hybrids just now being sold when the technology necessary to develope them has been around for at least 30 years?
The reasons are political, not reasons of practicality...
LMAO
Yep. Every single topic, every argument shot down and decimated. All you can say is nu uh but take an entire paragraph to do so. Sorry, couldn't help pointing out you take so long to say so little.
Your lack of intelligence is overwhelming. You've been spewing out nothing but opinion, and the only useless fact you did point out helped your argument in no way what so ever. You might as well have pointed out that light bulbs exist. It would have the same relevance.
[pfred2: You're obviously a coward who made up this "Vengence" account merely to attack me being as you've done nothing else with it as all. Another easily discernible FACT!]
Like I said, the idiocy is overwhelming. You still don't seem to know what facts are, and you're still just wrong. Are you ever right about anything in life? The real fact is you can't even do something as simple as count. You do know Sep 24, 2007 comes way before Apr 14, 2009 right? Of course you don't; that was the point I was making.
Decimated.
How this site is formatted I did not notice you had more than 2 comments beyond the ranting you've done in this thread. But viewing them all now I see you're always that way. You must also excuse my difficulty reading white text on a white background. Fact is you're really not worth looking at too closely. The less I know about you the better off I am!
Decimate
Like I said you're being a bit too optimistic. The only point you have is the one on top of your head.
White on white? Not only can you not count, you don't know your colors. It's white on orange. Is there something wrong with your computer too?
Way to use the obsolete definition of decimate. In fact, I'm sure the word decimate has never been used in that context, only decimatus. The first definition from dictionary.com
1. to destroy a great number or proportion of:
Also from wiktionary.org
The Cambridge Guide to English Usage states that the nonspecific use of this word to mean devastate or severely reduce the numbers of is ‘nowadays the commonest use of the word in both British and American English, and it’s registered without comment in modern dictionaries.’ It also advises against using numbers with the term, as ‘They are redundant where it means “reduce by one tenth,” and where it doesn't they confound the arithmetic.’The 23 occurrences of decimate in the British National Corpus — compare decimates, decimated, and decimating — almost all clearly accord with the nonspecific sense. The only references to the historical sense are two complaints about modern usage and its critics. Neither of these actually uses the term to mean "reduce by one-tenth".
You're seriously never right. That must be frustrating to you.
Even in your definition, that was AFTER the battle was already won. He would kill 10% more people as a lesson to the opponents; which I guess still fits well with what I'm doing now.
Decimated yet again.
http://en.wikipedia.org/wiki/Stirling_engine
It talks about their practical applications in there as well. You might learn something.
And normally makes sense when it replies to something, not spouting meaning gibberish which wastes everyone's time.
I am very curious, how the Diesel generator would be run, when there is no Diesel available (now please don't say "sunflower oil", as this would be too "green" for you, and - depending on the motor's technology - could lead to fast damages)?
There are small companies evolving, already producing series of Striling engine generators which can be run by anything producing heat AND already can be bought: http://www.genoastirling.com/pdf/Specifiche_3Kw_bicilindro.pdf
There are new types of Stirling engines (free piston engines), which even need less maintenance than the "normal" ones (which do NOT need lubrification).
And btw: Philips already had built a series of working Stirling generators back in the 50ies (!), but - one of the most remarkable "features" of man - they abandoned the idea and went the way of the "least resistance".
It is really astonishing, that mankind always starts to think of new technologies only when getting at a point where something - in this case fossile fuels - will no longer be available or - in the case of Japan - secure nuclear technology proves to not be as secure as being planned.
This discussion is getting pretty ridiculous!
We are not discussing about something like "Perendev motors" or "Overunity", we are talking about a kind of technology, which is existent and which is being developed more and more (due to the fact that the so very much easier way to use petrol-based technology will by the best meaning of the words "run out of fuel" in the not so very far future. Would you do a little more research in the internet, you would find, that actual Striling engines have an efficiency (fuel input to mechanical output) which is at least as high as modern Diesel engines (internal combustion).
And concerning your "impressive number" of Diesel generators: how many of those are really "green", having a particle filter and using an additive like "AdBlue"? Don't tell stories by quantity, switch to quality!
http://www.mackboring.com/CMFiles/Docs/Product_Brochure.pdf made by http://www.whispergen.com
Btw: When I experimented with battery-operated tubes in 1960,integrated circuits also were just a curiosity. SMD LEDs emitting white light and 1 W of power, nobody had an idea that this will be realized! Or do you really believe that the kind of camera module you will find in modern smart phones (1 sqcm incl. "flash LED" and 3 MP resolution) could have been dreamed of in the early seventies?
For the last decade the rule has been, that technological knowledge at university level has doubled every 5-6 years at an accelerating tendency.
Just wait less than a decade and you will see, what development Stirlings will go through. Or maybe someone really will show the proof of overunity engines .... ;-)
Greetz from Brazil!
http://en.wikipedia.org/wiki/Perpetual_motion
Too bad they only work if you lubricate them with snake oil. But until such a day they are curiosities at best I'm afraid.
You said above an Overwhelming number? 20 years ago there were far more petrol cars by comparison to today, does that mean they are better technology?
No, and they are worse for the environment. That is why despite the best efforts of the car companies there are more electric/hybrid/more efficient cars today.
What is the combined engine size of your cars?
Global warming? Didn't your tree hugger buddies send you the memo? Global warming is out today, now you're supposed to say Global Climate Change! I see insufficient proof that human activity is related to any change in the planet's climate. Those politics sound like nothing but hot air to me.
I've heard of no effort made by any car manufacturer to block the development or manufacture of electric or hybrid vehicles. Though many are resistant to fuel economy regulation that would strain their business.
Like many people today I own more trucks, SUV,s and vans than passenger vehicles. I'm down to just one car now. It is a 2.2L it does have 2 dual 45mm Weber sidedrafts on it though if that helps you out any :)
Take in your diesel generator, and an electric heater/fan.
All the food you want.
Now stay in there for two weeks. I wonder how long you could last in such a micro-climate. Maybe you will see that we *do* have an impact?
Now in mine I will have translucent solar cells on the roof and lots of trees inside, emulating the planet before man, a little.
Which would you prefer? Which could you survive in!?
How many trucks vans etc do you own!? The biggest engine in any vehicle I have ever owned is 2L.
You must not have seen the documentary "Who Killed the Electric Car". It's been on the Discovery channel a few times. Basically GM is responsible for NiMH batteries essentially(not formally) being banned from use in electric cars. GM used to own the patent, now Chevron does...
thanks!
Just realize that this power source it a very viable power source.
After all, it's simplicity provides a very simple source of power and makes it very efficient.
Hobby to you or not, theres great possibilities in this machine.
I'm sure the wheel was just pushed around for giggles and grins before someone realized they could use that thing.
The temperature a stirling engine runs at determines how much of the heat you put in gets converted to work output- its efficiency. For a commercial solar-powered engine, that might be 25%, but for the low temperature engines that run from the heat of someone's hand it's below 1%.
The useful output of an engine like this might be enough to run a few LEDs or a radio but it's never going to power your house. There are more efficient, less junky engines around which can produce useful amounts of power but they need a machine shop to build and a wood stove or large solar dish to power them, not a few candles.
Two thumbs up!
Jerry
Get it entered in the 3rd Epilog Challenge.
I am in the process of gathering parts to built a large sterling something like this to run off my wood stove, I have my second VCR just ready to crack open to see what goodies are inside.
My solenoid beam engine is a practice piece before I attempt to build a flash aluminium sterling.
Can you post any info more info or links to the design as this looks exactly the kind of design i have been looking for, I really like walking beams.