I wrote a long reply about the challenges of steam and deleted it. If a person wants to play around with steam engines… have at it. I expect you’ll have tons of fun building the engine and supporting systems. If you are very skilled and persistent… you might end up with a working engine. I would expect that engine would create a lot of heat and a little motive power but don’t let that stop you.
Steam is only efficiency at high temps and pressures… that’s just physics. High temperature and pressure steam is dangerous. Be safe.
750F/750psi sounds like murder machinery to me. 140F/60psi is more my speed. I get the Carnot number is going to be in the bilges, and I’ll be extremely lucky if I even get a quarter of that. But so what? The waste heat will heat the house. I can also make a Stirling engine out of old soup cans. So stiff competition between Newcomen, Stirling and thermal electric generator (TEG) is the way I see it.
Rindert
It isn’t useful to say micro steam is a waste of time and money for the individual interested in it,
but it is true to say that micro steam is inherently less efficient and a MUCH more complicated and expensive path to using biomass than gasification. I think we are all clear on that.
Here is the main problem with micro steam as I see it;
The lure of simplicity inherent in the Rankine cycle is almost never realized.
What could be more simple than boiling water over a fire, right? Lol!
By the time you have a working system it is twice as complicated as an Otto cycle gasifier setup, and you had to build everything yourself:)
But I still couldn’t say, ‘Don’t Bother’. By all means, go for it. Just make sure you understand what you are in for… which I’d guess MarkG does.
I’d guess you could get about 1.5 shaft hp out of that Amazon coil.
**Expander:
Uniflow, piston, POV (piston operated valve, aka ‘bash valve’) poppet valve.
Convert an air compressor. Use a Detroit diesel two stroke cylinder and piston set. Use a two stroke engine in a pinch. I used a valve out of a high pressure piston water pump for the POV.
I converted a Honda clone, which was more work than it was worth (but it worked well).
Here is a video of a converted V-twin air compressor I made. It was easy to get it to the ‘running’ stage, but it was far from done. Notice the oil/water problem (solved with cross head construction usually).
**Burner:
A wood stove won’t work. You need to leave all the energy in the smoke. Maybe a gasifier design or some other stoker or chip burner. Leave lots of room in your design budget for this element.
I built a smaller version of the old Greenwood furnace.
Eight hours of clean combustion per load, don’t have to split the wood.
**Water pump:
use a belt driven high pressure piston water pump with electric clutch. Simple on/off control.
**Regulation:
How do you control the thing? Throttle the steam with a governor? Let it work as hard as it can against a large load?
There is a lot of room for clever engineering in micro steam and if you can make it work, more power to you:) (ha ha)
You will probably have to make:
The boiler, the expander and valve gear, the burner, the safety valve, the boiler control system, the governor system, the water supply system, the exhaust heat exchanger, the lubrication system, etc.
Other people exploring steam. Pretty much the same as when us Mother Earther’s were looking for Alt energy in the late 60’s early 70’s. Never found a way for it to provide efficient motive power for homesteading. A few years back there was a website promoting little steam engines powering low rpm-high output alternators that I was interested in until people who tried building them couldn’t get the claimed results. I can’t find the site now. Seems like it was Blue Steam power or something similar but searching that comes up with with steam cleaning sites.
Have you looked into rocket stoves? I’ve built a few test models. They actually produce very little smoke. My favorite is the batch box rocket stove that Peter van den Berg has come up with. LINK
Rindert
The fire box / heat source for a steam boiler is a critical area for efficiency. As Chuck says, you can’t let all the smoke and heat out of the chimney and hope for a fuel-efficient process. The hot exhaust gases should preheat the intake air to keep more of that heat inside the system, like a condensing home heater/furnace. I’ve seen an advanced Stirling engine with that kind of combustion heater used to good effect. Related… don’t get me started on the Stirling engine rabbit-hole.
But please don’t take that comment/suggestion as encouragement. I’m solidly in Tom’s camp above on steam - have fun but don’t expect much!
Chuck… you have taken steam engines impressively far, still… I think lawn mower engine + gasifier is a much better starting place for off-grid motive power.
Hey Rindert,
Yeah ‘rocket stove’ combustors are a great way to meter the fuel and ensure complete combustion in that riser tube. I’ve built quite a few including an outdoor cook top for canning. My first steam boiler had one.
Aprovecho did a good job popularizing the low smoke cooker for the third world and the principles of efficient combustion necessary for biomass burners.
I like your build! Is it a horizontal feeder? I’ve seen people use various ways to make the horizontal feeders automatic.
Anthony, no doubt about it, steam is the hard way.
Nothing original in my experiments… it all came from the Steam Automobile folks. They collected the ‘doer’s’ in steam for awhile and still have some of the best ‘modern’ steam information. http://www.kimmelsteam.com/
Tom Kimmel bought up all the old guys projects over time and has a bit of a steam museum that is worth perusing for anyone interested in ‘modern’ steam.
Some philosophizing:
Everyone has to follow their own path, but just like gasification, we tend to re-invent the wheel. Rediscovering what was already done so long ago is a great (though expensive) education, but I think a lot of us would like to see enduring value in these things.
The premise is simple; take ubiquitous biomass and effectively use it to fuel a modern lifestyle.
Most of this forum knows how to use sticks to make an engine go (steam or woodgas).
But the value is something far more elusive and complicated… the things SteveU talks about.
The end to end system that includes labor and cost and convenience and how dirty it is and whether the wife can make it go and how long it will last and how dangerous it is perceived to be.
How difficult is it to make it part of your everyday life?
These questions, in the end, seem to be more important than what technology is actually involved.
If someone offered a micro steam system that could run unattended for eight hours on firewood, generated 200-300 watts electrical, heated my house and hot water, and had a reasonable service interval… for less than $10k, I’d buy it.
I wouldn’t care if it was gasification or steam…
I never thought to call it a horizontal feeder, but I guess that’s a good descriptive name. I like it.
The fire box allowed me to put about an 8x20 inch log in there with space for little stuff under it to start the burn. I after lighting I didn’t have to tend it for about 30 minutes. The firebox cooks a new log down into a pile of charcoal that is perfect for cooking the next log. I’ve thought about making the firebox bigger to allow larger logs, larger charges and longer intervals between tending. Maybe I could even load it with the full 40lbs of wood it would need to heat my house for a day. But I haven’t done it yet. Still room for development.
Rindert
Something like that might not be that not be that far away.
What if we set up a rocket mass heater with an eight inch riser, easily able to burn 60 lbs of wood in two hours? Thermal energy would be stored in black basalt gravel. The type used as road base for railroads. Copper tubing would be run through part of the thermal mass to heat your hot water. A sheet metal shroud and duct work would deliver heated air for space heating. A clothes dryer might be modified to draw heated air directly from the thermal mass. Electricity for lights, washer, refrigerator, dryer motor etc. might come from TEGs via battery and inverter. That leaves the cooking range. We might have to do propane for that. And maybe my imagination is getting tired. Your ideas?
Depending on where you live a solar furnace might supplement the rocket stove.
The idea would be to have you tend your energy system not more than two hours a day.
Rindert
Sadly, thermodynamics is against it, lol! At least the electricity part…
You need the 1600F gases directly off the fire in order to have the delta T for running an engine. If you dissipate that high temp gas into a large mass you end up with a lot of low grade heat and Carnot jumps up and says ‘qu’est-ce que?, no no!’.
At the risk of derailing this thread, you could use a LTD (low temperature differential) hot air engine but in order to generate any useful power you would need to process a ton of air like these guys.
The ultra slow speed is nice. You are back to designing and building your own everything.
The point is that Carnot is all about delta T. 2nd law makes low grade energy unavailable. This is the foundational problem with steam, very low delta T compared to internal combustion engines.
About 10 years ago I was involved with a couple that were working on producing steam with concentrating collectors that were daisy chained. They were able to produce steam but the pressure was to low to do any work other than space heating.
Mais ce n’est pas comme ça. L’orthographe est non, non, monsieur. Et nous sommes ridicules.
Yes I’m talking about large quantities of low quality, low delta T, thermal energy. So just put aside whatever you learned in engineering school and use what you learned on the farm. Get the job done the easiest way you can. Use heat directly when ever possible. Avoid all engines (energy converters) whenever possible. A hot rock might not be what you call technology, but it will sure keep a space warm.
Rindert
Hmm. Yes true about the mass low quality, low delta T, benefits in thermal energy for habitual/occupiable and concentrated grow areas heating RindertW.
Think instead of dense black basalt quarry rock of just using sized screened round stones river drain rock for you mass. You will get better predictable air transfer flow.
Now on the engine energy converters I have to beg to differ when it comes to making useable shaft power and useable amount of electricity.
Same, same reasoning as your wood heated mass thermal concept.
The base energy was solar origination. That collected and concentrated stored one cell at time over many trillions of cells over a months time period. To make actual concentrated wood density takes years of this part-year concentration.
Air oxygen combusting the wood we are rapidly releasing this low quality, long-time accumulated solar energy.
Thank you very much plants.
And it is this long time accumulation rapidly released, that allows us the high delta T’s in real-time.
So really it becomes a choice then of the best available at the present time energy converter.
It is not the 1860’s. It is not the 1910’s or even 1920’s. We are strong still in the quick ramping-up leap-forwards that was the 1940’s. Except refined decade by decade to be better, step by step; improved.
Anyone with just a small percentage of their annual working incomes can just buy a new production small IC piston Otto cycle engine. And these thourally modern available internal combustion engines have proven easily able to fuel on all grades types of commercial pump fuels.
Adaptable to many, many types of home DIY fuels too. Alcohols; esters; wood and char gasses, and more.
On that All Powered Labs sponsored “Escape from Berkley by Any Means Not Using Petroleum” time trial race to Nevada the #1 and #2 place winners used modern IC engines.
The custom built steam car even with all of the accumulated knowledge in the early 2000’s was reported to not even be able to make it out of the Berkley metro area.
My dumb, dumb in the last 18 years was initially going with a big heavy 950 pound 12 horsepower on diesel; engine. Son-of-a-bugger actually did need a true 2000 pound base mass added to not hop away running. The Wife would not get within 150 feet of its dual big external scary flywheels. The booming exhaust was hearable accross the whole one mile by five miles home valley. Dumb-dumb me going back to an all-must-be-brought-to-it 1870’s-1930’s type statioanry power system.
My second attempt was at least portable. Under 300 pounds. With factory electric starting. And the Wife would get up close and personal to turn key start and operate it. A “Changfa” 7.5 horsepower on diesel clone. 1940’s German engine techknowlegy transfered to → Japan → then placed in China by the Japanese occupational forces. The Chinses later copied, improved and made these by the millions.
Still got this one. Eco-Greens forced regulations that these could no longer be imported new into the USofA. No more complete engines. Parts only spotty available by direct importing. The part received often wrong. Needing hand fitting modifying to actually fit and work.
So the reasonable choice is then what is in current available production. Not 7500 or 20,000 hours life ideal. 2000 hours life at best. So get 2-3-4-5 like I have now.
10,000 hours of service possible than before having to fix and restore.
Ha! And extreme portability. Very discrete quiet. And now able to at collected points of use have invididual power converter units.
A steam energy converter for shaft power and you will realistically only be able to have one point of power source. Have to make up your own homestead grid distribution. What the gone big PV solar folks have to do.
Money. Time. And efforts.
You will only have so much to work with.
The patience and understanding of others in the household being your most limited resource of all.
I do not like having a crazy-man cone-hat placed onto me by my immediately live-with family.
So choose the hat you would have to wear carefully.
Steve Unruh
Hey Steve,
That is probably the most important grouping of words I’ve seen written on alt energy in a long time. I loved my 53 ferguson with the gasifier on the front but the reality was nobody but me would touch it. Same with the 65 Massey industrial. My very limited free time was being eaten up operating older finikey machinery alone. The 25 HP New holland that replaced them can be used by my 13 year old daughter with no problem. Come the apocalypse? well we will talk. I still have the skills to create power from biomass but its on the back burner. I love reading all the posts on projects though. My thoughts on steam have not changed much since the thread was originated but hey, everyone seems to need to do the same learning experiments to understand its limits and why a very smart generation that understood it perfectly put it aside 100 years ago.
Cheers, David
