# Most efficient Steam Engine?



## Greebe (Jan 30, 2010)

Just curious as to what the most efficient steam engine design is. I know this depends on the usage of the engine, but overall what would be the most efficient?

The reason that I ask is because I am interested in possibly building a mid sized steam engine that could act as a PTO for running several different pieces of equipment in a remote location. I know this might sound lofty, but that is why I want to start building some small models. To get the hang of the steam concept.

Living in Alaska made me think a lot about this concept. Shuttling in gas is a major pain, one which my wife and I did for some time. Wood and water are an abundance in Alaska, so the thought of a small steam engine that can be flown or carried by snowmachine in the winter seemed like a neat concept.

Thanks a lot,
Greebe


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## Jared (Jan 30, 2010)

I don't know a lot about it but it seems like a good question to ask is what kinds of rpms are you looking for? I like the idea. Several pieces of equipment in a remote location? Sounds like gold mining to me.


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## bearcar1 (Jan 30, 2010)

I believe that the engines incorporating the Corliss type of valving were heralded as some of the most efficient designs. However, they are a bit involved as far as setting up. When you are speaking of portability, what exactly did you have in mind as far as physical size/HP etc. The 'D' valve type engines were documented as having high frictional losses. There certainly are a myriad of possibilities to choose from. Also, what size of boiler?

BC1
Jim


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## QMAN56 (Jan 31, 2010)

Maybe off topic, but if energy to run things is your overall objective, is any of that watter running down a steep grade ? If yes, might be more straigth forward to set your self up to generate electrcity via hydro electric as water is in such abundance.


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## Kermit (Jan 31, 2010)

Also consider using flash boiler tubes instead of a traditional 'tank' type boiler. They suffer less from mineral deposits. Are much safer if they blow up, and can be run on any type of heat source you can imagine. 

Wind and Hydro are also very viable options. Three phase induction motors can be wired to generate electricity by simply adding some motor run capacitors between phases. The scheme is on the internet if you search for it.

Efficient and 'portable' seldom are seen in the same package.
Kermit


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## Richard1 (Jan 31, 2010)

Efficient and portable don't usually go together as Kermit said. If I was building it I would look to steam car engine designs as they have to be light and portable. For a boiler there was a Babcock and Wilcox style water tube boiler in the Model Engineer 10th July 1958 over all size 21 inches by 27 inches 31 inches high made out of 1/2 in and 3/4 inch tube with a steam and water barrel of 4 inches. If you are interested I can scan this for you. I would consider a single acting 4 cylinder 90 degree vee with poppet valves would probably be a good engine. I am perfectly prepared to have someone tell me I'm wrong.

Richard


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## Greebe (Jan 31, 2010)

Thanks for the replies. I guess my concept is one that could be portable in the sense that it would be small enough to easily transport via ATV, snowmachine, or a SuperCub(small plane), but have the power to do useful tasks. If I were using a gas engine it would probably be in the 5-hp. range. 

Hydro, as a few of you mentioned, is not a very viable option in Alaska due to the long cold winters. Plus I would like for this concept to be used anywhere, including places where you would only have a lake or standing water as well.

I know that steam engines can produce more torque than gasoline engines so I honestly dont know if that could mean that you could use a smaller horse steam engine. Maybe you guys could tell me how may HP I would need for the following tasks. Also I know that the more HP you want the larger the boiler so that would be a consideration as well.

The first use would be for power generation. All that would be needed is just enough to charge some 12V batteries. This would be for more or less low demand appliances such as 12V lights and communications in the form of CB radios. It would also be useful to be able to run an inverter to operate some 120V equipment such as power tools and possibly a laptop.

Other uses that I see would be for water pumping to get water to a cabin and for the steam engine. Also this could be used with a trash pump for sluicing.

A log splitter would be a big one. This could be either in old fashion guillotine version or screw splitter, or possibly to run a hydraulic pump for a hydraulic splitter?

Another big one would be for running a heavy-duty winch for moving logs and pulling logs up to position when building cabins.

If you guys have any suggestions on boiler size and engine size for such a concept please let me know. I would be very interested in what you guys have to say.

Thanks again,
Greebe


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## Greebe (Jan 31, 2010)

Kermit-- Do you have any links on info for flash tube boilers? Safety is obviously a concern. I do not want anything blowing up.  

Richard-- Yes, I would be very interested in that article. That would be awesome if you could scan it for me, I would be very grateful. 

Any info and plans would be much appreciated at this point.

Thanks'
Greebe


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## Kermit (Jan 31, 2010)

here is a link to a simple but understandable flash-mono-tube boiler.

http://www.dangerouslaboratories.org/genboiler.html


Take the design for what its worth, noting the web site name of course. No picture is shown of the generator driving an engine - so. Use this for info only.

There. I legally feel much better.  8)

Kermit


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## hammers-n-nails (Feb 1, 2010)

well greebe i like a steam engines just as much as the next guy but. if your just wanting an exuse to build a steam engine id go for somethng of the corliss type for efficieny but how you fire the boiler and how well its designed has just as much to do with it as anything. if you got plenty of wood around go for something simpler, D valve fixed cutoff and just throttle it.

the problem(s) your going to have using it for the things your talking about is that someone as to man the engine and boiler the entire time its bein operated. also by some rough calculation i believe you coud expect to get about 48 hours of operation from one chord of wood, i assume you would be burning some sort of pine. also a 5 hp engine with suitable base may weight.. 300lbs?? plus boiler. the traction engine were building has some added weight for the running gear but the whole thing should weigh about 2500-3000lbs and make about 10hp continuously. this being a fire tube boiler of course, much heavier than the flash type thats being discussed.

anyway the point im trying to make is that you can haul ALOT of gas for the time and energy you will spend building, operating, cutting wod for, maintainig and moving a steam engine.

i you want a steam engine ill help you any way i can but i think you will find it much less practical than a gas genertor.


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## Philjoe5 (Feb 1, 2010)

Heres a company that is currently selling plans and engines that are meant for useful work:

http://www.greensteamengine.com/

and another that sells engines only, I think, but may offer some assistance:

http://www.mikebrownsolutions.com/1hpapic.htm

I have no affiliation with these companies nor experience with them so caveat emptor

Cheers,
Phil


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## Bernd (Feb 1, 2010)

Greebe,

Check out logging books that show the logging industry of the 1800's and early 1900's for idea's on getting the logs out of the woods. For some ideas of the type of steam engines used do a search on "donkey engines". That's what they were called in the logging industry.

Bernd


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## Mainer (Feb 1, 2010)

Strictly in terms of efficiency, a steam turbine hooked to a generator might be the best, but I tend to agree with hammers-n-nails, it's REALLY hard to beat a gasoline engine for practicality.


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## Bernd (Feb 2, 2010)

I see a few members are suggesting using gas. Take a look at the OP's last paragraph in the original post. You might see why he wants to use steam. Also sounds like he has the time do all that too. 

Bernd


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## Noitoen (Feb 2, 2010)

Wouldn't a small steam launch engine with a vertical boiler do the job? If you have steam you don't need an engine to make a log splitter, you could use a cylinder with a wedge like those hydraulic ones (I think)


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## hammers-n-nails (Feb 2, 2010)

yeah bernd i see what hes saying but what i got from that was that he was under the impression that a steam engine setup would no be much bigger or heavier than a gas motor of the same power. a 5 hp steam engine is going to be more than 2 people can load by hand.

noitoen i thought about building a splitter like you say exept that to make the 64000lbs splitting force that a common gas/hydraulic splitter has a steam cylinder would have to be 23.5" diameter at 150 psi.


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## Noitoen (Feb 3, 2010)

You can still do the splitter with a smaller cylinder. Have you seen those pneumatic actuated oil pumps? With 7 Bar of air they make 200 Bar of oil pressure.


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## Blogwitch (Feb 3, 2010)

Noitoen, you will find they are called pressure intensifiers, and have been around longer than I can remember, they work on the principle of surface area, in your example, an air piston surface area of approx 30 sq ins driving an oil piston with a surface area of 1 sq in. A simple example is the use in pneumatic/hydraulic pop rivet guns.


With regards to efficiency, steam engines in the normal sense of the word just are aren't, that is why we are all not driving around in steam cars and flying in steam driven aircraft, although nuclear processes still use steam for their output, but I don't think that is a practical idea.

During WW2, Stuart Turner were making a small generating set that you could run by burning twigs etc in the boiler. They were designed for clandestine operations for 'spies' to recharge their transmitter batteries, and could be classed as portable. You can still pick them up today if you search deep enough, mainly on UK steam sites, the ones that sell old steam plants and generators. They are usually fairly expensive though, as they have become a collectors item. 

The most efficient 'standard' sort of steam engine is an expansion engine, where the steam is used at different pressures as it goes thru the engine, so in a triple expansion, the first to be fed would be the small high pressure cylinder, then the steam is passed from that to the medium pressure then to the low pressure, extracting as much energy from the steam as it can. There are still a few bulk carriers on the high seas that use them, and are just about competing with older low efficiency diesel engined ships. You can buy and make expansion engines from plans and usually castings in various sizes, but they definitely wouldn't be cheap to make.

It might pay you to have a look at Ray Hasbrooks offerings (now sadly departed), where his engines, although not super efficient, were fairly cheap to make from barstock and things like cylinder liners from cars. There are a couple of plans in the offering that might suit some of your ideas.

http://hasbrouck.8m.com/index.htm

There was a discussion on here a fair while ago about this topic, so a good search might bring it up. In that, it shot down in flames the 'new' engines on the block, like the so-called 'green engine'.

I hope that this can give you maybe another channel to follow.


Blogs


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## AlanHaisley (Feb 3, 2010)

hammers-n-nails  said:
			
		

> yeah bernd i see what hes saying but what i got from that was that he was under the impression that a steam engine setup would no be much bigger or heavier than a gas motor of the same power. a 5 hp steam engine is going to be more than 2 people can load by hand.



This is not strictly true. Granted, with boiler, firebox, plumbing and all, the weight is too much. I would assume though that the components would come in in pieces. Referring to
http://www.mikebrownsolutions.com/20hpse.htm
gives a weight of 150 pounds for a 20 HP engine. Brown's one cylinder mill engine weighs in at 50 pounds. I see the bulk and weight of the boiler as being more serious. 
By the way, Brown states that his two cylinder engine will require 20 pounds of wod per hour to run.



			
				hammers-n-nails  said:
			
		

> noitoen i thought about building a splitter like you say exept that to make the 64000lbs splitting force that a common gas/hydraulic splitter has a steam cylinder would have to be 23.5" diameter at 150 psi.



Only if you wanted to split the wood on one stroke of the engine. I'd assume rather that the engine would drive a low volume hydraulic pump. If necessary, the engine could rotate hundreds of cycles to drive the ram. With hydraulics you can trade off any feasable movement with pressure to get the job done.

Alan


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## Kermit (Feb 4, 2010)

Flash Steam Boiler - Google Book Result(2pgs)

Kermit


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## Bernd (Feb 4, 2010)

Not to knock Alan's link to the Mike Brown's steam engine, but have any of you checked out the rest of his web site: "Mike Brown Solutions". It makes me a bit leary. He also advertised a few times in Live Steam. I don't know if anybody has ever tried his steam engines. My instinct tells me "Buyer Beware"

Here's the link to the main page: http://www.mikebrownsolutions.com/index.html

Make up your own mind after browsing the site.

Bernd


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## mu38&Bg# (Feb 5, 2010)

The 20HP steam engine is exactly 20HP based on 200PSIG for ~50 percent of the stroke at 700RPM. Not being to familiar with steam, I can't say if the claim is realistic. If the valves and supply lines allow for 200PSI in the cylinder during that part of the stroke at 700RPM, then it should make rated power.


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## Maryak (Feb 6, 2010)

Dp,

Your calc, (a SWAG by me), is probably the theoretical Indicated Horespower. It takes no account of steam losses in the cylinder or the frictional losses of the moving parts. Even if you are producing an actual IHP of 20 you will lose at least a further 12-15% driving the engine itself before you do any work on the load.







Hope this helps


Best Regards
Bob


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## mu38&Bg# (Feb 6, 2010)

I understand there is loss between burning the fuel and turning the shaft. This is not different than an IC engine. The question I have is if you supply 200PSIG to the valves on this engine will it make 20 HP at 700RPM? The calc I did was BMEP, just like used in IC engines. To my surprised the figures were exactly 20HP, with no losses. So I wonder if the power spec is based on theory or if it was actually dynoed to rate it.

But, you're right. There is no way 100% of the 200PSI supplied can be converted to shaft power. I was thinking of it in terms of how it's used for IC engines. It is calculated based on the shaft power so all losses are already accounted for. So if the claim is based on input pressure and physical size of the engine, we can expect less than 20HP at the shaft. Any idea how much less?


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## Maryak (Feb 6, 2010)

Dp,

Off the top of my head around 25%.

Unknowns such as quality of steam, quality of insulation, length-size-no.of bends of pipes between boiler and engine. The list goes on.

Best Regards
Bob


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## shred (Feb 6, 2010)

I'd suggest that people/companies that did haul steam engines and boilers around the wilderness "back in the day", using wood for fuel, seemed to settle on the "donkey engine", which might say something still valid today about size, weight, and useful power output. I'd check into the various sizes those came in.


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## Richard1 (Feb 7, 2010)

Just random thoughts on your problem:-

1). Having driven this hand fired wood burning steamer 
	

	
	
		
		

		
		
	


	




 for a living in the past I don't think you can keep a sufficiently even firebox temperature hand firing wood to run a flash boiler. The less water you have in the boiler the more the fluctuations of hand firing will show up in the steam pressure. This isn't to say build a boiler with tons of water in it either but it is something to keep in mind.

2). The other point is the higher the pressure you have the smaller the engine can be for the same power which is why steam cars have been built to run on 1000PSI or more. Stanley were using 600PSI in 1911

3). Points 1 and 2 are probably incompatible.

Richard


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## Maryak (Feb 7, 2010)

Richard.

Which paddler is that, can't quite read the name.  ???

I have relieved aboard PS Marion out of Mannum South Aust.

The Shearer Steam car at the National Motor Museum in Birdwood SA operates at 350 psi using a coal fired Yarrow 3 drum water tube boiler. From memory the steam drum is about 10" OD and the whole thing is about 3ft tall. The two water drums are split in half to facilitate tube removal/replacement and the bottom 1/3 of the steam drum is a wrapper/tube plate. Quite a neat semi portable design.

Best Regards
Bob


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## Richard1 (Feb 7, 2010)

Bob,

PS Emmylou based in Moama works out of the port of Echuca, engine is a twin cylinder portable originally from a saw mill I think, 4.5 to 1 spur gear reduction to the paddleshafts if I remember correctly. I know of the PS Marion I think she was based at Echuca when I was working there, it was a long time ago. A year or two before that I had an interview for Chief (only) Engineer on the PS Melbourne which was a twin cylinder compound portable

Shearer steam car, I didn't know that one. I sent a scan of a B&W style water tube of similar size and pressure to a couple of people in this thread. This would seem to me to be a reasonable size for the job, reasonabley portable, have enough water capacity to smooth out the steam flow rate and of high enough pressure to make the engine of manageable size.


Best Regards

Richard


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## Kermit (Feb 7, 2010)

Something currently being manufactured as a high pressure water tube boiler. Forced draft combustion etc. etc.   I believe they indicated approx. 20-40 BHP for these models depending on pressure. About 5 feet tall.

They had a pdf of the boiler series I have attached for your inspection. not much info there though. 

Kermit 

View attachment Bryan_Pressure Vessels.pdf


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## Greebe (Feb 7, 2010)

Lots of good info in this post.

I still like the idea of this concept. I know that it might be hard to get things to the proper weight and size though. How much HP do you guys think would be needed for such a project?

The other thing that I have thought about is a Stirling type engine, but from what I understand is that they are not capable of producing very much power. The Stirling would be a much better type of engine as you could just supply heat via you wood fire and cold via a supply of stream water in the summer and ice or snow in the winter.

Is there a Stirling engine that could be feasibly sized so as to work for these types of task that I am looking for?

Thanks
Greebe


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## hammers-n-nails (Feb 8, 2010)

well i guess i was wrong about the weight. but as for how big of engine you need its really a matter of how fast you want it to do these things, a small motor will do just as heavy of work as a big one with proper gear reductions. its going to be hard to guess, you might just have to try something and see how it works for you. as for comparing gas to steam, horsepower is horsepower, the steam engine is going slow with alot of torque, the gas engine is going fast with less torque, with gear reduction its a wash.
i dont know much about stirling engines but from what i understand they are hard to build, hard to maintain, in efficient, and have a terrible power/ weight ratio.


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## marttin (Feb 11, 2010)

I usually don't horn in before reading all the posts on threads, but I read the first question. But let me ask you this,

have you research a wood gassifier? That's on my 'to-do' list. It doesn't seem that complicated, but I'm still to build the prototype. There's a few sites I visited and it does seem like a good alternative to hauling gas.

Run a search, I have a few links I can dig out if you can't find it.


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