I am a fairly complete “newbie” and have just in the last few months started my exploration of steam with a view in mind of applying it to a low-pressure solar-driven system to capture power to rechargeable (nickel-iron) batteries. I have found the comments fascinating reading.

I was pleased to find the “Green Steam” engine, but from what I’ve seen of the “Green Steam” videos, I was highly skeptical of the 10HP assertions for the 2-cylinder engines. It would appear my skepticism is well founded.

That said, I am looking to explore two discreet applications.

First, is a relatively low-powered “flash tube” system driven by sunlight to power my “battery charger”

Second, is a low-powered system to use to convert a Mazda B2200 to multi-fuel steam, preferably in the 30 HP range. The truck doesn’t need to go more than 100KPH/60MPH I figure; I just want it to be able to haul the same load effectively that it does now – a maximum of about 450KG/1000 lbs. Obviously, not filling the bed with boiler is important

I have access immediately to a drill press and band saw, and via various machinist friends, lathes of different sizes. I’m open to most any recommendation for how to approach these problems.

“nearly friction free.”
The design with rubber o-rings is definitely not friction free and unless you slather rubber lube the o-rings stick to the cylinder walls.

“The 12 cylinder still has only 1 bearing!”
Each cylinder has a bearing at either end. The swivel the steam enters by and the bearing connecting the con rod to the spider that connects to the crank. There is another bearing there plus the bearings supporting the drive shaft. Please look at the videos before commenting.

Pistons attached to a mechanism that turns a flywheel. The multi-piston approach is worse because the more mechanical pieces you have the more friction there is. There are Rankine cycle turbines that can efficiently gather waste heat right now. Its just that they cost a lot and very little energy is recovered.

Bottom line… Bob Greens inventions work and work well for not a lot of cost. His process and tech is always brilliant in simplicity.

Thanks JT and Mark for the discussion. I had high hopes for the green steam, but it is not sounding so great now….. Although I still may tinker around with recovering some energy from a shunt loop on a solar water heating system and trying to recover heat from the condenser. I was thinking of a closed loop (boiler-engine- condenser-pump ) that would contain a fluid with a boiling point of around 120 F. Any recommendations for a fluid with that kind of a working temp? As you can probably tell I’m new to the concept so any tips and pointers would be great.

Thank you!

I have a way to generate incredible amounts of heat to drive the steam engine.

I wish I were an engineer so I could build a prototype.

How does a person go about obtaining a grant from the govt?

The only overhead involved is the original outlay of money for the engine, the generator and the land to place the units upon.

It’s hard to trust anyone these days. I am afraid that if I share my thoughts that my idea will be stolen and I will get nothing for the invention.

Having much experience with small generation systems and steam machinery, I must agree with virtually all of what Mark Stacey has presented.

Fred Rosse

I am Rachin.UR B.Tech final year student. I am interested in taking a seminar about GREEN STEAM ENGINE. Please give me more detail about this engine. My email is “rachu0423[AT]yahoo.co.in”

Thank you,
rachin.ur

Anyhow, I have an unlimited suuply of wood.

I need at least 2 steam engines which are 35 hp.

Can anyone give me info on building them???

Thanks!

Monotube boilers (flash steam) don’t need certification by the way and don’t need to run at high pressures. They do need some experimentation as there is little hard information about them. The most famous monotube was in the Doble steam cars. A great deal of info is available in older model engineering publications as flash steam boats used to hold all the speed records

I’ve got myself a fairly small boiler that is “awaiting restoration” – see http://www.loligo.com/projects/steam/boiler/ and follow the obvious links for pictures. It’s not a tube boiler, and it’s terribly inefficient, but it’s a start – I’ll build a Yarrow boiler or something better after I get some more soot under my fingernails.

I’d never leave a boiler alone, no worries about that. My goal would be 75psi. And I’d treat the water in the boiler for anti-rust mixture, but being able to recycle the water without running it through an oil separator would be ideal. So I’m encouraged by your comments about running your engine without lubrication, but that goes against what I’ve learned and read.

Ideally, I’d like to use rainwater to avoid mineral buildup. I’d like to recycle the water without gumming up the boiler, since rainwater is a limited resource. This implies running without lube oil or getting an oil removal system, and I’m trying to avoid complexity and cost, hence my interest in the Green design.

Thanks for your comments on the Green steam engine. I’ll put my efforts first into my single-cylinder horizontal before I experiment with the Green system, but it sounds like you have little faith that the Green design could be used to efficiently get ~10hp.

JT

It sounds like you have a lot of experience with steam engines.

I am interested in the sites you mentioned and also any information you might be able to provide about converting another engine to a steam engine. I am interested in making an engine in the 5hp range or so.

Thanks

I quoted piston diameter, not piston area in square inches in my preamble. (easier for me to visualize) so 3″ = 7.07 Sq inch.

And no I wouldn’t scale it up, the design is marginal at best and even at the as drawn size at 50psi it will simply flog out.

You don’t need lubrication in the steam at 120 psi as long as you have no super heat. I run our steam boat with no lube but I do lubricate at shut down to keep the rust worms away (Can’t afford an all bronze engine!). The boiler water no matter what pressure should be treated other wise you will lose the boiler to the corrosion worms at an appalling pace and even 20 psi is a boiler. A boiler at 20psi producing enough steam to run 5 hp is going to be a big piece of kit just to get enough heating surface, and will still hold a lot of energy. You don’t ever want it to let go. I’ve dealt with a 200L oil drum idiots had got up to about 10 psi due to chemical reactions inside it very very scary and it was only lukewarm.

There are ways round this ie monotube but to get then to run stably requires a LOT of faffing about, and probably sacrifices of virgin stokers over James Watts grave at midnight.

Do you have local steam boaters? regattas you can travel to? You can find a lot of hands on and any steam boat owner will happily bore your ears off. We love to talk steam

Thanks for the figures. I didn’t quite get the same numbers as you, though:

IHP=PALN/33000

IHP=( (10)*(3)*(2/12)*(500) )/33000

IHP= (0.076 per piston) * 2 = 0.152 for 2 pistons

Is my calculation for the “stroke in feet” off? 2 inches is .167 feet.

A rough re-calc says that at 50psi avg pressure, 9 cubic inches of piston area per piston, 4 inches of stroke, and 1000 RPM would give 9.09 IHP. Quite an increase in size/speed/pressure to get to that number.

Anyway, the calculation is kind of beside the point. Would you say that this engine method, even with larger pistons and stroke, is a lost cause? The two benefits I see (no lubrication required, saturated low pressure steam) might outweigh the detractions, but only if it actually -works- as advertised.

The Strath Steam stuff is interesting, but as as Mike Brown’s engines. However, they both require fairly high pressure and lubrication, which requires expensive certified boilers and non-recyclable feedwater respectively. I understand the efficiency problems with creating the steam – I’m not thinking that this system is any magic bullet for exceeding any Carnot ‘brick wall’ efficiency barriers.

Would it be worth scaling this engine up to a reasonable size (5-8 hp) or is it not worth the time in your opinion?

JT

Sorry for the slow reply I hadn’t ticked the follow up comments box.

Lets skip to a bit of theory.
IHP = PALN/33000
This is a tool to figure out the theoretical (Indicated) Horse Power of a stream engine per cylinder
P is mean effective pressure
A is piston area in square inch
L is stroke in feet
N is rpm

If we plug in some numbers 3″ diameter bore 2″ stroke 500 rpm Mean effective pressure 10psi (assuming steam admission shuts of at 50% stroke) and 2 cylinders we end up with about 0.35 hp. Which seems about right. It would push a canoe along.

The next step it to determine what water rate this occurs at which determines the fuel consumption and thus the efficiency. A good unit say 4 hp at 120 psi with a little super heat would be lucky to do 10% fuel to shaft hp. Have a look at Strath steam http://www.strathsteam.com/ they supply units for remote area power to give you an idea of what a unit looks like. You need a good supply of fire wood and preferably a way to use a bucket load of hot water.

If you want some sites to visit (expect to do a LOT of reading) and some references sing out.

Cheers, Mark

I’m interested on your thoughts on this engine not as “designed” (since it sounds like there are no designs provided on the CD, only vague drawings) but on this engine as a concept. While 6mm may be insufficient to handle >20psi, is there a design modification that would make this more feasible? Can the pistons or entire engine be easily insulated to retain heat losses? Is it that the idea of this engine at any “reasonable” efficiency is impossible, or are there modifications that would make it at least useful?

It seems to me that this engine has three main features that are appealing:

1) Low pressure operation (I know that means low power, but if you increase piston size and stroke, maybe this gets better.)
2) Ability to use saturated steam (see #1)
3) No requirement for piston lubrication in the oil, allowing for closed-loop (or nearly closed-loop) recirculation without an oil separator

Other benefits (not primary)
A) No high-precision parts
B) Can be started from cold without petcock valves or risk of condensation damaging the piston
C) Apparently simple and inexpensive construction and maintenance

For a small (<6kw) powerplant, this actually might be reasonable. Capturing and converting ANY high-heat source into DC power as an adjunct to other power input sources seems like a win for me, even if it’s only run for a few hours a day. Certainly, not having to build a high-pressure boiler (and get certification for same) also seems like a win.

However, if there is no way to modify this engine to work at better than let’s say 10% efficiency, then it’s not much better than the refrigeration compressor route.

Are there solutions which compare favorably to the Green design with the 3 criteria listed above? Is it completely hopeless or is it just poor implementation in the designs you were provided?

JT