Most efficient Steam Engine?

[Greebe]

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

 

[Jared]

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.

 

[bearcar1]

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

 

[QMAN56]

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.

 

[Kermit]

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

 

[Richard1]

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

 

[Greebe]

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

 

[Greebe]

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

 

[Kermit]

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

 

[hammers-n-nails]

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.

 

[Philjoe5]

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

 

[Bernd]

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

 

[Mainer]

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.

 

[Bernd]

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

 

[Noitoen]

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)

 

[hammers-n-nails]

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.

 

[Noitoen]

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.

 

[Blogwitch]

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

 

[AlanHaisley]

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.

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

 

[Kermit]

Flash Steam Boiler - Google Book Result(2pgs)

Kermit