# Stirling Engines



## -TWO- (Mar 25, 2008)

I built a steam engine in H.S. metals shop, Mid 70's. While researching steam engines I first come across the concept of the Stirling engine. Over the years I've had an off & on interest in them & am always seeing practical applications for them, but I've never "known" one in person. I've googled them & know they're still in use in a limited capacity. Has any one had any experiance with Stirlings? Or have any opiniuns?


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## Argono (Apr 8, 2008)

I know over at www.otherpower.com I've read posts about how people use them to power fans for their wood stoves. They even had links to retailers selling them.


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## ace admirer (Oct 5, 2005)

wellll, they don't throttle too well, but could be good for constant loads.. there were several pumping companies at the turn of the last century that offered heat engines to power water pumps. the water also acted as the heat sink. i can't for the life of me remember the name of the pumper. redding? anyway. i always wanted to build a larger engine just for the heck of it.


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## OntarioMan (Feb 11, 2007)

There is a very neat heat engine video somewhere on the net - I think its youtube.com



ace admirer said:


> wellll, they don't throttle too well, but could be good for constant loads.. there were several pumping companies at the turn of the last century that offered heat engines to power water pumps. the water also acted as the heat sink. i can't for the life of me remember the name of the pumper. redding? anyway. i always wanted to build a larger engine just for the heck of it.


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## ET1 SS (Oct 22, 2005)

I have not dealt with them.

I do know that modern conventional submarines are powered by Sterling engines, so among the industry they are seen as the best non-nuclear choice.


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## ace admirer (Oct 5, 2005)

they are used on some of the subs because there is little noise generated with heat engines


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## artificer (Feb 26, 2007)

Once I get a bunch of projects out of the way, and the machine shop set up, I want to build something like the following:
Jim Dandy #6

Powered by a wood firebox, connected to a generator.

After that, I want to investigate a duplex stirling engine that uses wood or biomass to provide refrigeration.

Too many projects, not enough time...

Michael


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## Windy in Kansas (Jun 16, 2002)

New Zealand seems to lead in use of Stirling engines. NASA has worked with them quite a bit, partially for refrigeration.

There are kits available that aren't too expensive which allows you to build a small unit that will operate off of the heat from a cup of coffee, also the heat of your hand if I remember the advertisement correctly.

Here is but one company that offers a kit: http://www.stirlingengine.com/ Their list of engines shows the hand and coffee engine are different.


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## ace admirer (Oct 5, 2005)

i've got one of the coffie cup deals,,,it turns a little toy air plane propeller..

lets remember, energy out = energy in - inefficiencies. 

it works for nasa, because of the extreams of temperature. very hot on a surface facing the sun, very cold on a surface away from sun. since the heat engines are heat transfer engines you need a hot and a cold sink. 

not to change the thread, but remember the freon wheel that mother earth news had back in the seventies. used solar heat very slow rpm, but an interesting idea.


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## Windy in Kansas (Jun 16, 2002)

ace admirer said:


> not to change the thread, but remember the freon wheel that mother earth news had back in the seventies. used solar heat very slow rpm, but an interesting idea.


Yes I certainly remember the Wally Minto water wheel as it was called at the time. I still have 1970s literature from him or his company. A very brief brochure.
http://www.linux-host.org/energy/btempw.htm

When regulations were changed for propane bottles and overfill protective devices were required I had actually planned to buy up a bunch of old style bottles for next to nothing and finally proceed to build one. Nope, companies simply replaced the valve--often charging more than a new bottle would cost. 
So there went my experiment.

My local landfill nearly always has 50 to 100 propane bottles setting in a specific area. By law no scavenging is allowed. Still, I inquired about the bottles. Many are ones that were stolen and used to transport ammonia for meth manufacturing so would be too dangerous to use. Sigh! No freebies even if I could get the county to allow a one time scavenging.

I hauled and delivered propane for 7 years so have a fair idea of its properties. I had intended to use propane rather than freon due to input expense. With the price of freon today I doubt the project would be feasible at all. Still very intriguing though.


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## MELOC (Sep 26, 2005)

why would they be dangerous to use?


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## SolarGary (Sep 8, 2005)

Windy in Kansas said:


> Yes I certainly remember the Wally Minto water wheel as it was called at the time. I still have 1970s literature from him or his company. A very brief brochure.
> http://www.linux-host.org/energy/btempw.htm
> 
> When regulations were changed for propane bottles and overfill protective devices were required I had actually planned to buy up a bunch of old style bottles for next to nothing and finally proceed to build one. Nope, companies simply replaced the valve--often charging more than a new bottle would cost.
> ...


Hi,
I suppose this is not very scientific, but I remember seeing a Mythbusters episode in which they tried to get one of these wheels to work. They were able to get it to rotate, but useful power output was next to nothing. It seemed like they did a credible job of building it to me.

Gary


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## MELOC (Sep 26, 2005)

i saw that episode. i think they concluded it would have to be huge to generate useful power.


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## -TWO- (Mar 25, 2008)

lets remember, energy out = energy in - inefficiencies. 

it works for nasa, because of the extreams of temperature. very hot on a surface facing the sun, very cold on a surface away from sun. since the heat engines are heat transfer engines you need a hot and a cold sink. 


Waste heat out the stove pipe on a cold winter day. Argono made referance to running a fan In the link he posted. (Great link, by the way) Manys the time I've thought a stirling would really "shine" under those conditions. As I understand the princable, the power output is similar to an electric motor.


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## OntarioMan (Feb 11, 2007)

The "machines that don't work" - there is an entire website devoted to these - ala perpetual motion. Whether its gravity, properties of gas or whatever - the machines are rather useless, but they're still very interesting. Many of the designs have been around forever, yet they appear to be "re-invented" every so often. 



SolarGary said:


> Hi,
> I suppose this is not very scientific, but I remember seeing a Mythbusters episode in which they tried to get one of these wheels to work. They were able to get it to rotate, but useful power output was next to nothing. It seemed like they did a credible job of building it to me.
> 
> Gary


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## ET1 SS (Oct 22, 2005)

It also works underwater, as their primary concern is quite machinary taht can produce power.


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## Windy in Kansas (Jun 16, 2002)

SolarGary said:


> Hi,
> I suppose this is not very scientific, but I remember seeing a Mythbusters episode in which they tried to get one of these wheels to work. They were able to get it to rotate, but useful power output was next to nothing. It seemed like they did a credible job of building it to me.
> 
> Gary


I don't know what Mythbusters even is, but yes I have read of a number of homebuilt trials of the water wheels and none were successful. However quite a number of the builders spoke of doing things a little differently, etc than the original.

I think while Mr. Minto was still living he proposed that a unit needed to have 20 foot spokes making the wheel 40 feet in diameter. I expect for efficiency there needs to be a lot of spokes as well to get as weight moving as possible.

We know they work from the experiences of others, just not successfully.


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## ET1 SS (Oct 22, 2005)

http://www.kockums.se/Submarines/gotland.html

The Gotland Class - one of the world's most modern classes of submarine. It was the world's first submarine class in operation with a Stirling air independent propulsion (AIP) system.

Three submarines of the Gotland class, HMS Gotland, HMS Uppland and HMS Halland are now in service with the Royal Swedish Navy, and 2 SÃ¶dermanland Class submarines. All use stirling engines.


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## ace admirer (Oct 5, 2005)

yeah, the fan for the wood stove is on sale at the local northern tool store for $139.00.

if i remember correctly, the myth buster thing used a vat of hot water (am i remembering this correctly?) if so ...the experiment was in error. the differential in temperature cannot occur at top and bottom, but slightly off center of top and bottom, so the wheel has a defined heating and cooling bias either leading the top or lagging the top and bottom. but again,,,its a slow speed thing not very usefull for power making,,,,it is useful to automatically open and shut vent shutters and to make solar arrays tilt and follow the sun using the transfer of liquid to vapor in opposing chambers....reminds me of the little red headed water bobbing glass birds...

so yeah, if you have waste heat going up a stack and a cold junction,,,it could make some use of the wasted heat... but to think that an engine will run making 2 hp of power for 24 hours on an arm load of wood,,,,,the math will not work out. 

i remembered the name of the antique hot air ,water pumping engine: rider-ericsson , the few examples left in the usa sell for over two thousand....i have plans for a model one in a book around here somewhere. 

i still want to make a big (not model stuff) heat engine.....just too lazy to do the detailed machining...wished i knew enough to knock together one from fabrications.


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## -TWO- (Mar 25, 2008)

Seems like I read somewhere, awhile back that Woodmizer had in the works, a sawdust burner that powered a stirling, haven't heard anymore about it. Wouldn't mind building one myself, but it'd help to see one in action. I'll checkout the one northern tool has for sale.


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## watcher (Sep 4, 2006)

The Mythbuster's set up showed it worked. But they build a very small one using propane tanks. IIRC, it was only about 4' tall. That would give them a lever of only about 2 feet long with a few pounds. Not going to get much energy out of it.

I'm looking into it but I'm not looking at using propane because my end project (as planned now) is going to be 10-20 foot tall and that would be way too much propane to be playing with. One small leak and a spark and bad things could happen. 

Currently I'm looking at using one of the new 'ozone friendly' refrigerants and water in AL tanks.

My biggest problems are wind loads (I live in a hurricane area) and gearing. Most of these wheels run at one (1) rpm. There's going to be a lot of loss trying to get any usable rpm out of it.


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