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Why doesn't anyone sell a Stirling that produces power?

Posted: Mon Oct 13, 2008 11:09 am
by jgposner
Come On!!! There are a million people experimenting with Stirling
engines but no one selling them that can produce power. I want one
that I can hook up to my wood burning stove to use as a generator. Is
it just not practical? Why won't one of you geniuses build one to
sell. It doesn't have to be pretty, it doesn't have to be small, it
can even have multiple cyllinders. Give me an estimate?

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Mon Oct 13, 2008 12:48 pm
by bptdude___2569
HA HA HA HA HA


Ok, serious now.
Be nice, please.
Many of us want exactly what you are saying.
Finally, it looks like small working engines will become avaible in the next year or two, after perhaps decades of people pouring their hearts into this.

Here is your estimate.
In three years you will see a working engine in the 2 - 5 horsepower range available on the mass market.

I have learned that I too had ideas like you, but stand down now, because of the people who put real time and money into this.

- Joe

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Mon Oct 13, 2008 1:40 pm
by cchagnot
Modern Stirling Engines are complex thermodynamic machines that are very difficult to
translate into a simple, reliable mechanical device for mass production. Sure, it's easy to
build one that goes..'Clanka, clanka, clanka', but produces no real work. A number of
good, high tech companies (and that's what it takes) have been working for years on a
number of different models for different markets. The price of oil has finally made these
machines more than competitive with conventional internal combustion power. It takes a
VERY large investment to set up to produce in mass quantities to make the engines
affordable. A number of groups are now in that process. Joe is right. In a few years you'll
finally be able to buy a Stirling Engine.

Stay tuned....

Catherine

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Mon Oct 20, 2008 7:07 am
by rtopf
Joel,

The question should read "Why doesn't anyone sell a Stirling that produces power for cheap?"

They are out there, they are not cheap.
Sunpower has offered a 1 Kw freepiston in the past for $10 grand.

You may also ask "why are they so expensive?" That is a much more complicated answer but there is some underlying basic truths.

The Phillips company, who are largley responsible for reviving Stirling engine design in the last century said that the cost is closley tied to the cost of the hot end materials. In their studies they found that the cost to produce the hot end was 60% of the total cost of the engine development. Once a design goes to production, that percent is even higher.

Simply put, it's the same problem the Rev, Stirling ran into. If you can find a material that can remain strong at red-hot temperataures, it is probably expensive to buy and very difficult to machine into the needed shape.

Rick

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Mon Jan 26, 2009 9:45 pm
by goel.tx
Has anyone tried using ceramic materials for the hot end? There are
sintered ceramics that are very cost effective, but likely not
lightweight. Also, some new nanomaterials are very strong at high
temperatures.

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Tue Jan 27, 2009 9:56 am
by stan.hornbaker
BECAUSE no one will buy one at the price that will give the manufacturer a reasonable return on the cost of design and manufacture!

You can't buy a silk purse at the price of a sow's ear.

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Tue Jan 27, 2009 12:23 pm
by ralphmarlow
Look on youtube. There are videos of Stirling fans and you can see them run. Stirling engines that produce power are very expensive and only work well for limited applications. Some are even solar powered.

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Tue Jan 27, 2009 10:55 pm
by jgposner
Hi everybody. It looks somebody is doing exactly what I was really after, which was a generator from the heat of a wood burning stove. Except they don't use a Stirling engine. Instead they have a steam engine with several small cyllinders. The site http://www.cyclonepower.com/ has made an external combustion engine that can run off of waste heat of a vehicle or from a fireplace. They have a 10kw generator. They will be available in the summer 2009. Although I am facinated with the Stirling engine, these people have a product small and relatively cheap almost ready for market. Check them out. I plan on at least buying a lawn mower with this engine on and probably the generator too.
Thanks for all the replies. I am still interested in more replies about the Stirling engine.
Joel

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Thu Jan 29, 2009 7:36 am
by stan.hornbaker
If you ill go to the Waste Heat Forum and look for the latest posts on "The Ultimate Hot Air External Combustion Engine?" You will find an example of such a engine (scam).

Thermal Engines in Alabama sell two models of Stove Top Stirling Engine FANS.

Response to Why doesn't anyone sell a Stirling that produces power?

Posted: Fri Jan 30, 2009 6:09 am
by jgposner
Thanks for your input William. I like the fan and I'm glad this company is producing something useful but I am really looking forward to the day when these engines get powerfull enough to produce electricity.

About your comment on the External combustion engine. If it is a scam, it won't last very long. One person in the forum you pointed me to expressed doubt that Cyclonepower's engine can produce as much power as an internal combustion engine of the same size. We'll see. Aren't there simple tests for that. And if they can't, they won't get pattents. Bottom line is, if they can produce a lawnmower that cuts grass then I'll buy it. If they can produce a 10k generator that runs off the heat from my wood burning stove, I'll buy that too. I guess I'll call the pattent office before I make my purchase this summer.