# Stirling engine



## Homely (Aug 22, 2007)

http://en.wikipedia.org/wiki/Stirling_engine
Does anyone have one? How much do they run? What are the cons?
I saw a thing on the Discovery channel about the solar energy farm in California, I think. It was my first time hearing about Stirling engines. They seem really intriguing and to have a lot of potential.


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## ET1 SS (Oct 22, 2005)

Germany has been using them in manufacture of submarines for two decades.


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## bluetick (May 11, 2002)

I have a small one on top of my woodstove to help circulate the heated air. It is called Heat Wave, and is similar to the Eco fan. It was a gift, but I think it may cost more than the Eco fan.

The stove top temperature needs to reach at least 400 to 425 degrees before I give it a light spin to activate it. It's an interesting gadget!


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## Metcalf (Feb 15, 2007)

There is some really interesting work being done with free piston sterling engines with linear alternators. They don't have any rotating parts and can be sealed to use a working gas like hydrogen or helium effectively. 

There was some work done a few years ago that built a few prototypes. They where biomass co-generation units that used wood chips or sawdust. They produced about 1kw or electricity per hour and 4kw/hr of recoverable heat for hot water or space heating. If I remember right they used about 1.5kg of wood an hour. 

I always wanted to build a unit for myself....very neat technology.

I think I have a PDF somewhere if anyone would like to see more information.


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## Homely (Aug 22, 2007)

I saw a wood chip version at the sunmachine website. They have solar and gas versions, too.


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## Windy in Kansas (Jun 16, 2002)

The thing I find interesting about Stirling engines is how long they have been around and are used so little. I understand about a century ago there were quite a number of them in use, but without modern technology and science they often seized up and went to the scrap pile.

NASA has been researching Stirling uses for a long time. 
http://www.grc.nasa.gov/WWW/tmsb/stirling.html
http://www.sti.nasa.gov/tto/spinoff1998/hm7.htm

The country of New Zealand seems to be a proponent of Stirling engine use. 
http://www.mech.canterbury.ac.nz/research/stirlingcycle.shtml

The WhisperGen work is usable and interesting. I'm not aware of US importers.
http://www.whispertech.co.nz/ I believe these units are often used on boats and at remote cabins.

As mentioned submarines belonging to a number of countries use Stirling technology.


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## Windy in Kansas (Jun 16, 2002)

The thing I find interesting about Stirling engines is how long they have been around and are used so little. I understand about a century ago there were quite a number of them in use, but without modern technology and science they often seized up and went to the scrap pile.

NASA has been researching Stirling uses for a long time. 
http://www.grc.nasa.gov/WWW/tmsb/stirling.html
http://www.sti.nasa.gov/tto/spinoff1998/hm7.htm
I seem to recall reading that they are using them in sort of a reverse manner to act as refrigerators in one application.

The country of New Zealand seems to be a proponent of Stirling engine use. 
http://www.mech.canterbury.ac.nz/research/stirlingcycle.shtml

The WhisperGen work is usable and interesting. I'm not aware of US importers.
http://www.whispertech.co.nz/ I believe these units are often used on boats and at remote cabins.

As mentioned submarines belonging to a number of countries use Stirling technology.

Amazon lists some books on the technology.
http://www.amazon.com/Next-Great-Thing-Stirling-Engine/dp/0393036197


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## YoungOne (Aug 22, 2006)

http://www.stirling-tech.com/stirlingengine.htm

5HP comercialy produced sterling engine. Go figure that there no longer sold in the US.
If I can get a model working (2HP+) I hope to go with a dual fuel (???) A fresnel lens on a tracker (24X36 can melt Copper, thats well over the 900degree estimate), and a closed burner for for those not so sunny days (probably propane).


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## MN Mom (May 19, 2003)

Problem with Hot air engines is they are heavy for their output. 

A 5hp briggs weighs 30lbs and a 5 hp hot air engine weights 200lbs.

Here are some links if you want to play out in the shop.


http://www.boydhouse.com/ 

http://www.bekkoame.ne.jp/ 

The fan on your wood stove is not a hot air engine. It is a electric motor ran by some sort of heat sensity diode.


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## dcross (Aug 12, 2005)

I believe the UK is using them in homes as a co-gen unit.


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## Dahc (Feb 14, 2006)

Stirling engines are for the rich but can be made by the poor. They are not promoted here because they do not offer the govt any revenue. Plain and simple the US gov doesn't want you disconnected from the grid. Just like the super efficient diesel powered gens available to any third world country which will never make it through customs and arrive at your house in the US.

I have tried to promote this idea on this forum many times in the last two years but there seems to be little interest. A stirling engine doesn't take a certain temperature to operate but instead, requires a temperature differential.

I have posted Lenz's machine here before and here it is again:

http://www.windstuffnow.com/main/stirling_generator.htm

It's a homemade permanent magnet alternator run by a sterling engine. There are many sources of heat that we have access to always that are not being utilized. Various forms of engine exhaust, roof heat, solar radiation. The fresnel lens someone else mentioned was also an idea I had. I still believe it's an awesome idea for the one who has the ingenuity, equipment and finances to make it happen. One could probably build a very nice set-up for less than $1500. Maybe a little more if he/she had to have their parts fabricated by someone else.

P.S. If you search for stirling engines on youtube, you'll see lots and lots of homemade engines used in various applications. Some just for show but others that are very handy and well engineered tools.


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## Dahc (Feb 14, 2006)

MN Mom said:


> The fan on your wood stove is not a hot air engine. It is a electric motor ran by some sort of heat sensity diode.


Actually, if it is not a stirling (which it is very possible it is), it would be a thermo-electric generator which is also powered by a temperature differential. Two dissimilar metals, one exposed to heat, the other remains cooler, each producing a positive or negative charge from it's state.

Cellphone GPS units and non electric exit signs are good examples of this. The exit signs for industrial use (prisons, factories, schools and hospitals) use tritium, a low grade radioactive element, for their heat source. One can produce a thermo-electric generator by using copper and a ferrite material (iron). Attach leads and cool the iron or steel and heat the copper and you will produce usable low amperage power. 

Todays most common applications are Seebeck generators, peltier modules and thermopiles which are all basically thermoelectric generators used in different ways. The peltier is a cooler, the seebeck is a heater and the thermopile is a generator. The peltier and seebecks use electric current which is applied to produce certain temps, cooler or hotter and the thermopile is to get power from the temps already present. All very neat stuff and very hidden from the eyes of commoners such as myself.


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## longshadowfarms (Nov 27, 2002)

Wanted to bump this as alternative energy has come a long way in the last couple of years. We're looking at building, quite likely off-grid (currently living off-grid but we don't own this) and have some ideas roaming about our brains about producing electric off of the same system we're using to heat the house. Initial idea is to have underfloor radiant with the fluid heated by wood, possibly using the same wood heat to run the electric in winter. Possibly combine with some solar for summer use. Any thoughts?

http://www.tegpower.com/products.html


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## ||Downhome|| (Jan 12, 2009)

I was checking out sterling engines recently. 

the guy at green power science , Dan Rojas has a few videos on them.

he is working on converting a Air compressor into one.

[ame]http://www.youtube.com/watch?v=yX8d78b45M4&feature=results_main&playnext=1&list=PLDA953E21634E09D7[/ame]

personally I would machine new pistons for the application instead of what he has going on.


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