New millenium steam power

[Kermit]

Anyone else seen this? I'm still trying to understand how it works. Might be interesting to the pressure-phobic, as it runs on very low pressure.

http://www.greensteamengine.com/index.html

Puzzling, eh?

[Mad Scientist]

Interesting little engine!

The bearing at the flywheel end looks like it might be something like a 'swash plate' - an alternative to a crankshaft for converting reciprocating motion (pistons) to rotary motion (crankshaft).

I'll bet that the 2-cylinder version isn't self-starting - just spin the flywheel in the desired direction, so reversing is a simple matter of stoping the engine and then spinning the flywheel in the opposite direction.

I suspect that we'll see more interesting engines, just like back in the 70's when the 'energy crisis' occurred. You can't beat a steam engine for the ability to burn easily-obtainable renewable fuels, and I can't wait to see what the inventors will come up with!

Tom

[Jay Greer]

Kind of reminds me of a hydraulic pump motor; the kind that runs off of an eccentric plate. It might be a real breakthrough though.
Jay

[George Roberts]

"extremely efficient"

I thought high efficiency required high temperature differentials and high pressure differentials.

[B&W]

the efficiency is probably relating to the Mechanical efficiency rather than the efficiency obtained from the steam cycle

Since there seems to be little parts moving in bearings after the pistons and before the flywheel i would imagine this area would be more efficient than a regular recipricotating engine?

Also it looks like the steam has to condense inside the engine to "pull" the piston back down so this again would reduce the amount of heat wasted in a conventional condenser in a steam cycle?

I am actually dying to know more about this engine?

[hokiefan]

"extremely efficient"

I thought high efficiency required high temperature differentials and high pressure differentials.


Quite right. This is basic thermodynamics. Without a large energy drop (pressure differential) most of the input energy is simply exhausted to the atmosphere. You can't get high efficiency with a low pressure design, its just not possible.

Pretty neat mechanical design though.

Cheers,

Bobby

[moTthediesel]

"extremely efficient"

I thought high efficiency required high temperature differentials and high pressure differentials.


Yeah, therein lies the rub! That's thermo dynamics 101 :)

The interesting thing about this to me though is how simple it is. Even if it works (and granted, that's a BIG IF) only as well as a conventional low pressure steam engine, it could be a godsend in third world areas. I could imagine lots of uses (local electrical generation, water pumping, etc) where it could be fired by waste stream (cane stalks, coconut husks, etc) materials. It looks like it could be built and repaired in almost any boondock machine shop too.

Could be pure snake oil though, -- somebody here should make one and try it!

I love those copper pipe cap cylinders! Like the Guiness Boys say -- "BRILLIANT!" :D

moT

[Bob Cleek]

Fascinating energy transfer system and it seems that's what's patented. The steam piston part of it isn't really all that remarkable, or efficient, as noted above. Note that while he has a lot of neat pictures of the engines, some animated, he doesn't show us what it looks like actually operating under steam, except in one picture of the thing adapted as an outboard on a canoe. I'd expect you'd be seeing a whole lot of leakage out of those cylinders... maybe like "stand back" amounts! That sure seems to be the case with the canoe picture. I'd sure like to see that linkage hooked up to pistons machined to the usual tolerances as in a comparable regular steam engine. It seems to make sense that the spring loaded linkage would permit operation at lower pressures, but what's the torque output.

Notice that, as with a lot of hobby developed "toy" engines, the guy doesn't give us any technical data on the engines, such as load and horsepower curves, weight of steam consumed per HP and so on. He could have said a lot with adequate technical data.

Now, what also isn't addressed as far as I could see is always the biggest issue with all these "better mousetrap" steam engines, the designing of which has been an active hobby for many years. That issue is torque power. You can make a "steam engine" that will spin an axle very fast with little or no effort. Hero's orignal steam engine used this principle, as do modern steam turbines. That is fine if you want to spin a small little prop, but doing that, as in an internal combustion boat engine spinning a high speed prop, isn't all that efficient. What you want for steamboat efficiency, which is to say transfering the maximum amount of heat energy into the maximum amount of forward movement of the boat, is the torque power to spin a large wheel. That is what this engine must be able to do if it is ever to serve as a useful marine engine.

As for the use of small steam engines in underdeveloped countries, as usual, Mahatma Ghandi beat us to it, or so it seems.

http://www.tinytechindia.com/steamengine.htm

The Indian technology is merely a knock off of any number of stock marine engines from a hundred years ago, and likely every bit as useful and efficient. Keep in mind, though, that the efficiency "kicker" with steam engines isn't so much the engine, but the boiler. It's a lot easier to find a traditional steam engine with a relatively high efficiency rating, than it is to find a traditional boiler with a relatively high efficiency rating. That said, I have a new furnace at home that is something like ninety percent plus efficient, or so they claim. It does direct enough of the heat it generates to the inside of the house that it only needs a piece of two inch PVC pipe for a flue! I take "Energy Star" efficiency ratings with a grain of salt, but I thought a PVC chimney was pretty impressive. It only gets warm to the touch when the furnace is going full blast. If it were possible to apply that insulation technology to steam generation in a package suitable for a small boat, we'd have something to sink our teeth into!

[B&W]

He could have said a lot with adequate technical data.


I sure would love to see him take a draw card on the unit with those "conrods"(?) going everywhere. :)

I still like the design - excuse the pun but the eccentricity of it seems to touch the very essence of steam engineering.

[Nicholas Scheuer]

Rotary steam engines are not exactly new. I recall seeing something similar years ago. Consider how vibration from repiricating pistons has been reduced to virtually zero with the pair of pistons moving in opposite directions.

Moby Nick

[ssor]

Too many subjective superlatives concerning simplicity and efficiency.

[Bob Cleek]

Right on about the superlatives! The one thing that has always impressed me about the steamboating fraternity is their acceptance of the fact that "good enough" is just that. They are inveterate tinkerers, always looking to improve their mechanical systems, but they don't seem to get obsessive about it. Basically, as long as the damn boiler doesn't blow up, they all seem to have fun. And, since we are on the subject, it bears noting that modern boilers (we're not talking 1850 racing riverboats here) a statistically one hell of a lot safer than a gasoline, or even a diesel engine in a boat.

The other thing that the guy touting this new engine design isn't talking about is the fact that you have to judge the "steam plant," not just the steam engine. It's all of a piece. The boiler has to be just right for the engine, the engine just right for the wheel, the wheel just right for the hull, the hull just right for steam propulsion. A steam engine isn't like an outboard you can just hang on any hull, pull the cord and go... unless it's a steam outboard!

http://www.nmpproducts.com/dgtw04b.jpg

http://www.nmpproducts.com/dgtw03.jpg

Those steamboat guys are pretty crazy!

[George Roberts]

I guess my work is done...

[SamSam]

Her is what the patent is for...

The present invention is a device for converting rotary movement into reciprocating movement.This seems to be the black tube in the middle which is

a flexible rod made of helically wound wires It doesn't sound as if it's a new steam engine, just a slightly different way of transmitting power.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6647813.PN.&OS=PN/6647813&RS=PN/6647813

[Kermit]

See 'em running:
http://www.youtube.com/watch?v=GZ41rKx8XoM&feature=related

[Ross Faneuf]

An inventive little engine. Overall thermal efficiency (based on joules/BTUs released by fuel burning) are going to be low - I bet below 10%. Historically, reciprocating steam engine efficency maxed out in the first third of the 20th century in the 40% range. That's with medium-quality steam with the engine exhausting into a condenser.

This engine would have higher efficiency exhausting into a condenser (so that the exhaust pressure is below atmospheric pressure), but that's something of a challenge to construct with a hobbyist-built setup. And I still bet it wouldn't top 10%.

If people want real numbers, I can always dig out my old copy of Keenan's Steam Tables and check it out. The real catch with steam is all the energy you have to put into the liquid phase to turn it to a gas, which you then lose when the steam exhausts from the engine.

That's one of the reasons gas turbines or diesels have/are supplanting steam turbines - they don't have a phase change which sucks up energy. (And of course, both are way simpler than a steam turbine plant).

[heimlaga]

Tor has some interresting things going on:

Block your credit card before you look at the link. I warned you.:rolleyes:

http://www.bjorklundsteam.com/